[PATCH RFC 01/77] PCI/MSI: Fix return value when populate_msi_sysfs() failed

[PATCH RFC 01/77] PCI/MSI: Fix return value when populate_msi_sysfs() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/pci/msi.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index d5f90d6..b43f391 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -719,7 +719,7 @@ static int msix_capability_init(struct pci_dev *dev,
 
 	ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
 	if (ret)
-		goto error;
+		goto out_avail;
 
 	/*
 	 * Some devices require MSI-X to be enabled before we can touch the
@@ -732,10 +732,8 @@ static int msix_capability_init(struct pci_dev *dev,
 	msix_program_entries(dev, entries);
 
 	ret = populate_msi_sysfs(dev);
-	if (ret) {
-		ret = 0;
-		goto error;
-	}
+	if (ret)
+		goto out_free;
 
 	/* Set MSI-X enabled bits and unmask the function */
 	pci_intx_for_msi(dev, 0);
@@ -746,7 +744,7 @@ static int msix_capability_init(struct pci_dev *dev,
 
 	return 0;
 
-error:
+out_avail:
 	if (ret < 0) {
 		/*
 		 * If we had some success, report the number of irqs
@@ -763,6 +761,7 @@ error:
 			ret = avail;
 	}
 
+out_free:
 	free_msi_irqs(dev);
 
 	return ret;
-- 
1.7.7.6

Re: [PATCH RFC 01/77] PCI/MSI: Fix return value when populate_msi_sysfs() failed

[Ben Hutchings]

On Wed, 2013-10-02 at 17:39 -0700, Jon Mason wrote:
> On Wed, Oct 02, 2013 at 12:48:17PM +0200, Alexander Gordeev wrote:
> > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> 
> Since you are changing the behavior of the msix_capability_init
> function on populate_msi_sysfs error, a comment describing why in this
> commit would be nice.
[...]

This function was already treating that error as fatal, and freeing the
MSIs.  The change in behaviour is that it now returns the error code in
this case, rather than 0.  This is obviously correct and properly
described by the one-line summary.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [PATCH RFC 01/77] PCI/MSI: Fix return value when populate_msi_sysfs() failed

[Jon Mason]

On Thu, Oct 03, 2013 at 10:46:21PM +0100, Ben Hutchings wrote:
> On Wed, 2013-10-02 at 17:39 -0700, Jon Mason wrote:
> > On Wed, Oct 02, 2013 at 12:48:17PM +0200, Alexander Gordeev wrote:
> > > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > 
> > Since you are changing the behavior of the msix_capability_init
> > function on populate_msi_sysfs error, a comment describing why in this
> > commit would be nice.
> [...]
> 
> This function was already treating that error as fatal, and freeing the
> MSIs.  The change in behaviour is that it now returns the error code in
> this case, rather than 0.  This is obviously correct and properly
> described by the one-line summary.

If someone dumb, like me, is looking at this commit and trying to
figure out what is happening, having ANY commit message is good.  "Fix
the return value" doesn't tell me anything.  Documenting what issue(s)
would've been seen had the error case been encountered and what will
now been seen would be very nice.

> 
> Ben.
> 
> -- 
> Ben Hutchings, Staff Engineer, Solarflare
> Not speaking for my employer; that's the marketing department's job.
> They asked us to note that Solarflare product names are trademarked.
> 

[PATCH RFC 02/77] PCI/MSI/PPC: Fix wrong RTAS error code reporting

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 arch/powerpc/platforms/pseries/msi.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 6d2f0ab..009ec73 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -467,7 +467,7 @@ again:
 	list_for_each_entry(entry, &pdev->msi_list, list) {
 		hwirq = rtas_query_irq_number(pdn, i++);
 		if (hwirq < 0) {
-			pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
+			pr_debug("rtas_msi: error (%d) getting hwirq\n", hwirq);
 			return hwirq;
 		}
 
-- 
1.7.7.6

[PATCH RFC 03/77] PCI/MSI/s390: Fix single MSI only check

[Alexander Gordeev]

Multiple MSIs have never been supported on s390 architecture,
but the platform code fails to report single MSI only.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 arch/s390/pci/pci.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index f17a834..c79c6e4 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -427,6 +427,8 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 	pr_debug("%s: requesting %d MSI-X interrupts...", __func__, nvec);
 	if (type != PCI_CAP_ID_MSIX && type != PCI_CAP_ID_MSI)
 		return -EINVAL;
+	if (type == PCI_CAP_ID_MSI && nvec > 1)
+		return 1;
 	msi_vecs = min(nvec, ZPCI_MSI_VEC_MAX);
 	msi_vecs = min_t(unsigned int, msi_vecs, CONFIG_PCI_NR_MSI);
 
-- 
1.7.7.6

Re: [PATCH RFC 03/77] PCI/MSI/s390: Fix single MSI only check

[Martin Schwidefsky]

On Wed,  2 Oct 2013 12:48:19 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

> Multiple MSIs have never been supported on s390 architecture,
> but the platform code fails to report single MSI only.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  arch/s390/pci/pci.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index f17a834..c79c6e4 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -427,6 +427,8 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
>  	pr_debug("%s: requesting %d MSI-X interrupts...", __func__, nvec);
>  	if (type != PCI_CAP_ID_MSIX && type != PCI_CAP_ID_MSI)
>  		return -EINVAL;
> +	if (type == PCI_CAP_ID_MSI && nvec > 1)
> +		return 1;
>  	msi_vecs = min(nvec, ZPCI_MSI_VEC_MAX);
>  	msi_vecs = min_t(unsigned int, msi_vecs, CONFIG_PCI_NR_MSI);
> 

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

[PATCH RFC 04/77] PCI/MSI/s390: Remove superfluous check of MSI type

[Alexander Gordeev]

arch_setup_msi_irqs() hook can only be called from the generic
MSI code which ensures correct MSI type parameter.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 arch/s390/pci/pci.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index c79c6e4..61a3c2c 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -425,8 +425,6 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 	int rc;
 
 	pr_debug("%s: requesting %d MSI-X interrupts...", __func__, nvec);
-	if (type != PCI_CAP_ID_MSIX && type != PCI_CAP_ID_MSI)
-		return -EINVAL;
 	if (type == PCI_CAP_ID_MSI && nvec > 1)
 		return 1;
 	msi_vecs = min(nvec, ZPCI_MSI_VEC_MAX);
-- 
1.7.7.6

Re: [PATCH RFC 04/77] PCI/MSI/s390: Remove superfluous check of MSI type

[Martin Schwidefsky]

On Wed,  2 Oct 2013 12:48:20 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

> arch_setup_msi_irqs() hook can only be called from the generic
> MSI code which ensures correct MSI type parameter.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  arch/s390/pci/pci.c |    2 --
>  1 files changed, 0 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index c79c6e4..61a3c2c 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -425,8 +425,6 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
>  	int rc;
> 
>  	pr_debug("%s: requesting %d MSI-X interrupts...", __func__, nvec);
> -	if (type != PCI_CAP_ID_MSIX && type != PCI_CAP_ID_MSI)
> -		return -EINVAL;
>  	if (type == PCI_CAP_ID_MSI && nvec > 1)
>  		return 1;
>  	msi_vecs = min(nvec, ZPCI_MSI_VEC_MAX);

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

[PATCH RFC 05/77] PCI/MSI: Convert pci_msix_table_size() to a public interface

[Alexander Gordeev]

Make pci_msix_table_size() to return a error code if the device
does not support MSI-X. This update is needed to facilitate a
forthcoming re-design MSI/MSI-X interrupts enabling pattern.

Device drivers will use this interface to obtain maximum number
of MSI-X interrupts the device supports and use that value in
the following call to pci_enable_msix() interface.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 Documentation/PCI/MSI-HOWTO.txt |   13 +++++++++++++
 drivers/pci/msi.c               |    5 ++++-
 drivers/pci/pcie/portdrv_core.c |    2 ++
 3 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index a091780..35b2d64 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -255,6 +255,19 @@ MSI-X Table.  This address is mapped by the PCI subsystem, and should not
 be accessed directly by the device driver.  If the driver wishes to
 mask or unmask an interrupt, it should call disable_irq() / enable_irq().
 
+4.3.4 pci_msix_table_size
+
+int pci_msix_table_size(struct pci_dev *dev)
+
+This function could be used to retrieve number of entries in the device
+MSI-X table.
+
+If this function returns a negative number, it indicates the device is
+not capable of sending MSI-Xs.
+
+If this function returns a positive number, it indicates the maximum
+number of MSI-X interrupt vectors that could be allocated.
+
 4.4 Handling devices implementing both MSI and MSI-X capabilities
 
 If a device implements both MSI and MSI-X capabilities, it can
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index b43f391..875c353 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -928,11 +928,12 @@ int pci_msix_table_size(struct pci_dev *dev)
 	u16 control;
 
 	if (!dev->msix_cap)
-		return 0;
+		return -EINVAL;
 
 	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
 	return msix_table_size(control);
 }
+EXPORT_SYMBOL(pci_msix_table_size);
 
 /**
  * pci_enable_msix - configure device's MSI-X capability structure
@@ -962,6 +963,8 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
 		return status;
 
 	nr_entries = pci_msix_table_size(dev);
+	if (nr_entries < 0)
+		return nr_entries;
 	if (nvec > nr_entries)
 		return nr_entries;
 
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 31063ac..b4d86eb 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -80,6 +80,8 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
 	u32 reg32;
 
 	nr_entries = pci_msix_table_size(dev);
+	if (nr_entries < 0)
+		return nr_entries;
 	if (!nr_entries)
 		return -EINVAL;
 	if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES)
-- 
1.7.7.6

Re: [PATCH RFC 05/77] PCI/MSI: Convert pci_msix_table_size() to a public interface

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 02:10:43PM -0400, Tejun Heo wrote:
> On Wed, Oct 02, 2013 at 12:48:21PM +0200, Alexander Gordeev wrote:
> > Make pci_msix_table_size() to return a error code if the device
> > does not support MSI-X. This update is needed to facilitate a
> > forthcoming re-design MSI/MSI-X interrupts enabling pattern.
> > 
> > Device drivers will use this interface to obtain maximum number
> > of MSI-X interrupts the device supports and use that value in
> > the following call to pci_enable_msix() interface.
> 
> Hmmm... I probably missed something but why is this necessary?  To
> discern between -EINVAL and -ENOSPC?  If so, does that really matter?

pci_msix_table_size() is kind of helper and returns 0 if a device does
not have MSI-X table. If we want drivers to use it we need return -EINVAL
for MSI-X incapable/disabled devices. Nothing about -ENOSPC.

> tejun

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

[PATCH RFC 06/77] PCI/MSI: Factor out pci_get_msi_cap() interface

[Alexander Gordeev]

This update is needed to facilitate a forthcoming re-design
MSI/MSI-X interrupts enabling pattern.

Device drivers will use this interface to obtain maximum number
of MSI interrupts the device supports and use that value in the
following call to pci_enable_msi_block() interface.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 Documentation/PCI/MSI-HOWTO.txt |   15 +++++++++++++++
 drivers/pci/msi.c               |   33 +++++++++++++++++++++------------
 include/linux/pci.h             |    6 ++++++
 3 files changed, 42 insertions(+), 12 deletions(-)

diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index 35b2d64..1f37ce2 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -169,6 +169,21 @@ on any interrupt for which it previously called request_irq().
 Failure to do so results in a BUG_ON(), leaving the device with
 MSI enabled and thus leaking its vector.
 
+4.2.5 pci_get_msi_cap
+
+int pci_get_msi_cap(struct pci_dev *dev)
+
+This function could be used to retrieve the number of MSI vectors the
+device requested (via the Multiple Message Capable register). The MSI
+specification only allows the returned value to be a power of two,
+up to a maximum of 2^5 (32).
+
+If this function returns a negative number, it indicates the device is
+not capable of sending MSIs.
+
+If this function returns a positive number, it indicates the maximum
+number of MSI interrupt vectors that could be allocated.
+
 4.3 Using MSI-X
 
 The MSI-X capability is much more flexible than the MSI capability.
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 875c353..ca59bfc 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -812,6 +812,21 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
 	return 0;
 }
 
+int pci_get_msi_cap(struct pci_dev *dev)
+{
+	int ret;
+	u16 msgctl;
+
+	if (!dev->msi_cap)
+		return -EINVAL;
+
+	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
+	ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
+
+	return ret;
+}
+EXPORT_SYMBOL(pci_get_msi_cap);
+
 /**
  * pci_enable_msi_block - configure device's MSI capability structure
  * @dev: device to configure
@@ -828,13 +843,10 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
 int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
 {
 	int status, maxvec;
-	u16 msgctl;
 
-	if (!dev->msi_cap)
-		return -EINVAL;
-
-	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
-	maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
+	maxvec = pci_get_msi_cap(dev);
+	if (maxvec < 0)
+		return maxvec;
 	if (nvec > maxvec)
 		return maxvec;
 
@@ -859,13 +871,10 @@ EXPORT_SYMBOL(pci_enable_msi_block);
 int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
 {
 	int ret, nvec;
-	u16 msgctl;
 
-	if (!dev->msi_cap)
-		return -EINVAL;
-
-	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
-	ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
+	ret = pci_get_msi_cap(dev);
+	if (ret < 0)
+		return ret;
 
 	if (maxvec)
 		*maxvec = ret;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index da172f9..2fa92ef 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1144,6 +1144,11 @@ struct msix_entry {
 
 
 #ifndef CONFIG_PCI_MSI
+static inline int pci_get_msi_cap(struct pci_dev *dev)
+{
+	return -1;
+}
+
 static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
 {
 	return -1;
@@ -1185,6 +1190,7 @@ static inline int pci_msi_enabled(void)
 	return 0;
 }
 #else
+int pci_get_msi_cap(struct pci_dev *dev);
 int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec);
 int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec);
 void pci_msi_shutdown(struct pci_dev *dev);
-- 
1.7.7.6

Re: [PATCH RFC 06/77] PCI/MSI: Factor out pci_get_msi_cap() interface

[Alexander Gordeev]

On Thu, Oct 03, 2013 at 10:52:54PM +0100, Ben Hutchings wrote:
> On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> >  #ifndef CONFIG_PCI_MSI
> > +static inline int pci_get_msi_cap(struct pci_dev *dev)
> > +{
> > +	return -1;
> [...]
> 
> Shouldn't this also return -EINVAL?

Yep, all inliners here are better to return -EINVAL.
Will do unless someone speaks out against.

> Ben.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

[PATCH RFC 08/77] PCI/MSI: Get rid of pci_enable_msi_block_auto() interface

[Alexander Gordeev]

As result of recent re-design of MSI/MSI-X interrupts enabling
pattern pci_enable_msi_block_auto() interface became obsolete.

To enable maximum number of MSI interrupts for a device the
driver will first obtain that number from pci_get_msi_cap()
function and then call pci_enable_msi_block() interface.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 Documentation/PCI/MSI-HOWTO.txt |   30 ++----------------------------
 drivers/pci/msi.c               |   20 --------------------
 include/linux/pci.h             |    7 -------
 3 files changed, 2 insertions(+), 55 deletions(-)

diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index 40abcfb..4d0525f 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -133,33 +133,7 @@ static int foo_driver_enable_msi(struct foo_adapter *adapter, int nvec)
 	return rc;
 }
 
-4.2.3 pci_enable_msi_block_auto
-
-int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *count)
-
-This variation on pci_enable_msi() call allows a device driver to request
-the maximum possible number of MSIs.  The MSI specification only allows
-interrupts to be allocated in powers of two, up to a maximum of 2^5 (32).
-
-If this function returns a positive number, it indicates that it has
-succeeded and the returned value is the number of allocated interrupts. In
-this case, the function enables MSI on this device and updates dev->irq to
-be the lowest of the new interrupts assigned to it.  The other interrupts
-assigned to the device are in the range dev->irq to dev->irq + returned
-value - 1.
-
-If this function returns a negative number, it indicates an error and
-the driver should not attempt to request any more MSI interrupts for
-this device.
-
-If the device driver needs to know the number of interrupts the device
-supports it can pass the pointer count where that number is stored. The
-device driver must decide what action to take if pci_enable_msi_block_auto()
-succeeds, but returns a value less than the number of interrupts supported.
-If the device driver does not need to know the number of interrupts
-supported, it can set the pointer count to NULL.
-
-4.2.4 pci_disable_msi
+4.2.3 pci_disable_msi
 
 void pci_disable_msi(struct pci_dev *dev)
 
@@ -175,7 +149,7 @@ on any interrupt for which it previously called request_irq().
 Failure to do so results in a BUG_ON(), leaving the device with
 MSI enabled and thus leaking its vector.
 
-4.2.5 pci_get_msi_cap
+4.2.4 pci_get_msi_cap
 
 int pci_get_msi_cap(struct pci_dev *dev)
 
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 583ace1..1934519 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -849,26 +849,6 @@ int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
 }
 EXPORT_SYMBOL(pci_enable_msi_block);
 
-int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
-{
-	int ret, nvec;
-
-	ret = pci_get_msi_cap(dev);
-	if (ret < 0)
-		return ret;
-
-	if (maxvec)
-		*maxvec = ret;
-
-	nvec = ret;
-	ret = pci_enable_msi_block(dev, nvec);
-	if (ret)
-		return ret;
-
-	return nvec;
-}
-EXPORT_SYMBOL(pci_enable_msi_block_auto);
-
 void pci_msi_shutdown(struct pci_dev *dev)
 {
 	struct msi_desc *desc;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2fa92ef..13bf88d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1154,12 +1154,6 @@ static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
 	return -1;
 }
 
-static inline int
-pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
-{
-	return -1;
-}
-
 static inline void pci_msi_shutdown(struct pci_dev *dev)
 { }
 static inline void pci_disable_msi(struct pci_dev *dev)
@@ -1192,7 +1186,6 @@ static inline int pci_msi_enabled(void)
 #else
 int pci_get_msi_cap(struct pci_dev *dev);
 int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec);
-int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec);
 void pci_msi_shutdown(struct pci_dev *dev);
 void pci_disable_msi(struct pci_dev *dev);
 int pci_msix_table_size(struct pci_dev *dev);
-- 
1.7.7.6

[PATCH RFC 09/77] ahci: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/ata/ahci.c |   56 ++++++++++++++++++++++++++++++++-------------------
 1 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 9d715ae..f1c8838 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1091,26 +1091,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 {}
 #endif
 
-int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv)
+int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
+			 struct ahci_host_priv *hpriv)
 {
-	int rc;
-	unsigned int maxvec;
+	int rc, nvec;
 
-	if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
-		rc = pci_enable_msi_block_auto(pdev, &maxvec);
-		if (rc > 0) {
-			if ((rc == maxvec) || (rc == 1))
-				return rc;
-			/*
-			 * Assume that advantage of multipe MSIs is negated,
-			 * so fallback to single MSI mode to save resources
-			 */
-			pci_disable_msi(pdev);
-			if (!pci_enable_msi(pdev))
-				return 1;
-		}
-	}
+	if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+		goto intx;
+
+	rc = pci_get_msi_cap(pdev);
+	if (rc < 0)
+		goto intx;
+
+	/*
+	 * If number of MSIs is less than number of ports then Sharing Last
+	 * Message mode could be enforced. In this case assume that advantage
+	 * of multipe MSIs is negated and use single MSI mode instead.
+	 */
+	if (rc < n_ports)
+		goto single_msi;
+
+	nvec = rc;
+	rc = pci_enable_msi_block(pdev, nvec);
+	if (rc)
+		goto intx;
 
+	return nvec;
+
+single_msi:
+	rc = pci_enable_msi(pdev);
+	if (rc)
+		goto intx;
+	return 1;
+
+intx:
 	pci_intx(pdev, 1);
 	return 0;
 }
@@ -1277,10 +1291,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];
 
-	n_msis = ahci_init_interrupts(pdev, hpriv);
-	if (n_msis > 1)
-		hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
 	/* save initial config */
 	ahci_pci_save_initial_config(pdev, hpriv);
 
@@ -1335,6 +1345,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	 */
 	n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
 
+	n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
+	if (n_msis > 1)
+		hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
 	host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
 	if (!host)
 		return -ENOMEM;
-- 
1.7.7.6

[PATCH RFC 10/77] ahci: Check MRSM bit when multiple MSIs enabled

[Alexander Gordeev]

Do not trust the hardware and always check if MSI
Revert to Single Message mode was enforced. Fall
back to the single MSI mode in case it did. Not
doing so might screw up the interrupt handling.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/ata/ahci.c |   17 +++++++++++++++++
 drivers/ata/ahci.h |    1 +
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index f1c8838..3a39cc8 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1091,6 +1091,14 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 {}
 #endif
 
+static int ahci_get_mrsm(struct ahci_host_priv *hpriv)
+{
+	void __iomem *mmio = hpriv->mmio;
+	u32 ctl = readl(mmio + HOST_CTL);
+
+	return ctl & HOST_MRSM;
+}
+
 int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 			 struct ahci_host_priv *hpriv)
 {
@@ -1116,6 +1124,15 @@ int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 	if (rc)
 		goto intx;
 
+	/*
+	 * Fallback to single MSI mode if the controller enforced MRSM mode 
+	 */
+	if (ahci_get_mrsm(hpriv)) {
+		pci_disable_msi(pdev);
+		printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n");
+		goto single_msi;
+	}
+
 	return nvec;
 
 single_msi:
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 1145637..19bc846 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -91,6 +91,7 @@ enum {
 	/* HOST_CTL bits */
 	HOST_RESET		= (1 << 0),  /* reset controller; self-clear */
 	HOST_IRQ_EN		= (1 << 1),  /* global IRQ enable */
+	HOST_MRSM		= (1 << 2),  /* MSI Revert to Single Message */
 	HOST_AHCI_EN		= (1 << 31), /* AHCI enabled */
 
 	/* HOST_CAP bits */
-- 
1.7.7.6

[PATCH RFC 11/77] benet: Return -ENOSPC when not enough MSI-Xs available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/emulex/benet/be_main.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index 100b528..3e2c834 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -2378,6 +2378,8 @@ static int be_msix_enable(struct be_adapter *adapter)
 					 num_vec);
 		if (!status)
 			goto done;
+	} else (status > 0) {
+		status = -ENOSPC;
 	}
 
 	dev_warn(dev, "MSIx enable failed\n");
-- 
1.7.7.6

[PATCH RFC 12/77] benet: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/emulex/benet/be_main.c |   38 ++++++++++++++------------
 1 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index 3e2c834..84d560d 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -2366,29 +2366,23 @@ static int be_msix_enable(struct be_adapter *adapter)
 	else
 		num_vec = adapter->cfg_num_qs;
 
-	for (i = 0; i < num_vec; i++)
-		adapter->msix_entries[i].entry = i;
+	status = pci_msix_table_size(adapter->pdev);
+	if (status < 0)
+		goto fail;
 
-	status = pci_enable_msix(adapter->pdev, adapter->msix_entries, num_vec);
-	if (status == 0) {
-		goto done;
-	} else if (status >= MIN_MSIX_VECTORS) {
-		num_vec = status;
-		status = pci_enable_msix(adapter->pdev, adapter->msix_entries,
-					 num_vec);
-		if (!status)
-			goto done;
-	} else (status > 0) {
+	num_vec = min(num_vec, status);
+	if (num_vec < MIN_MSIX_VECTORS) {
 		status = -ENOSPC;
+		goto fail;
 	}
 
-	dev_warn(dev, "MSIx enable failed\n");
+	for (i = 0; i < num_vec; i++)
+		adapter->msix_entries[i].entry = i;
+
+	status = pci_enable_msix(adapter->pdev, adapter->msix_entries, num_vec);
+	if (status)
+		goto fail;
 
-	/* INTx is not supported in VFs, so fail probe if enable_msix fails */
-	if (!be_physfn(adapter))
-		return status;
-	return 0;
-done:
 	if (be_roce_supported(adapter) && num_vec > MIN_MSIX_VECTORS) {
 		adapter->num_msix_roce_vec = num_vec / 2;
 		dev_info(dev, "enabled %d MSI-x vector(s) for RoCE\n",
@@ -2400,6 +2394,14 @@ done:
 	dev_info(dev, "enabled %d MSI-x vector(s) for NIC\n",
 		 adapter->num_msix_vec);
 	return 0;
+
+fail:
+	dev_warn(dev, "MSIx enable failed\n");
+
+	/* INTx is not supported in VFs, so fail probe if enable_msix fails */
+	if (!be_physfn(adapter))
+		return status;
+	return 0;
 }
 
 static inline int be_msix_vec_get(struct be_adapter *adapter,
-- 
1.7.7.6

[PATCH RFC 13/77] bna: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/brocade/bna/bnad.c |   34 ++++++++++++------------------
 1 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
index b78e69e..d41257c 100644
--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -2469,21 +2469,11 @@ bnad_enable_msix(struct bnad *bnad)
 	if (bnad->msix_table)
 		return;
 
-	bnad->msix_table =
-		kcalloc(bnad->msix_num, sizeof(struct msix_entry), GFP_KERNEL);
-
-	if (!bnad->msix_table)
+	ret = pci_msix_table_size(bnad->pcidev);
+	if (ret < 0)
 		goto intx_mode;
 
-	for (i = 0; i < bnad->msix_num; i++)
-		bnad->msix_table[i].entry = i;
-
-	ret = pci_enable_msix(bnad->pcidev, bnad->msix_table, bnad->msix_num);
-	if (ret > 0) {
-		/* Not enough MSI-X vectors. */
-		pr_warn("BNA: %d MSI-X vectors allocated < %d requested\n",
-			ret, bnad->msix_num);
-
+	if (ret < bnad->msix_num) {
 		spin_lock_irqsave(&bnad->bna_lock, flags);
 		/* ret = #of vectors that we got */
 		bnad_q_num_adjust(bnad, (ret - BNAD_MAILBOX_MSIX_VECTORS) / 2,
@@ -2495,15 +2485,19 @@ bnad_enable_msix(struct bnad *bnad)
 
 		if (bnad->msix_num > ret)
 			goto intx_mode;
+	}
 
-		/* Try once more with adjusted numbers */
-		/* If this fails, fall back to INTx */
-		ret = pci_enable_msix(bnad->pcidev, bnad->msix_table,
-				      bnad->msix_num);
-		if (ret)
-			goto intx_mode;
+	bnad->msix_table =
+		kcalloc(bnad->msix_num, sizeof(struct msix_entry), GFP_KERNEL);
+
+	if (!bnad->msix_table)
+		goto intx_mode;
 
-	} else if (ret < 0)
+	for (i = 0; i < bnad->msix_num; i++)
+		bnad->msix_table[i].entry = i;
+
+	ret = pci_enable_msix(bnad->pcidev, bnad->msix_table, bnad->msix_num);
+	if (ret)
 		goto intx_mode;
 
 	pci_intx(bnad->pcidev, 0);
-- 
1.7.7.6

[PATCH RFC 14/77] bnx2x: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c |   54 ++++++++++-------------
 1 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 61726af..edf31d2 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -1564,7 +1564,7 @@ void bnx2x_free_irq(struct bnx2x *bp)
 
 int bnx2x_enable_msix(struct bnx2x *bp)
 {
-	int msix_vec = 0, i, rc;
+	int msix_vec = 0, nvec, i, rc;
 
 	/* VFs don't have a default status block */
 	if (IS_PF(bp)) {
@@ -1590,60 +1590,52 @@ int bnx2x_enable_msix(struct bnx2x *bp)
 		msix_vec++;
 	}
 
+	rc = pci_msix_table_size(bp->pdev);
+	if (rc < 0)
+		goto no_msix;
+
+	nvec = min(msix_vec, rc);
+	if (nvec < BNX2X_MIN_MSIX_VEC_CNT(bp))
+		nvec = 1;
+
 	DP(BNX2X_MSG_SP, "about to request enable msix with %d vectors\n",
 	   msix_vec);
 
-	rc = pci_enable_msix(bp->pdev, &bp->msix_table[0], msix_vec);
+	rc = pci_enable_msix(bp->pdev, &bp->msix_table[0], nvec);
+	if (rc)
+		goto no_msix;
 
 	/*
 	 * reconfigure number of tx/rx queues according to available
 	 * MSI-X vectors
 	 */
-	if (rc >= BNX2X_MIN_MSIX_VEC_CNT(bp)) {
-		/* how less vectors we will have? */
-		int diff = msix_vec - rc;
-
-		BNX2X_DEV_INFO("Trying to use less MSI-X vectors: %d\n", rc);
+	if (nvec == 1) {
+		bp->flags |= USING_SINGLE_MSIX_FLAG;
 
-		rc = pci_enable_msix(bp->pdev, &bp->msix_table[0], rc);
+		bp->num_ethernet_queues = 1;
+		bp->num_queues = bp->num_ethernet_queues + bp->num_cnic_queues;
+	} else if (nvec < msix_vec) {
+		/* how less vectors we will have? */
+		int diff = msix_vec - nvec;
 
-		if (rc) {
-			BNX2X_DEV_INFO("MSI-X is not attainable rc %d\n", rc);
-			goto no_msix;
-		}
 		/*
 		 * decrease number of queues by number of unallocated entries
 		 */
 		bp->num_ethernet_queues -= diff;
 		bp->num_queues = bp->num_ethernet_queues + bp->num_cnic_queues;
+	}
 
+	if (nvec != msix_vec)
 		BNX2X_DEV_INFO("New queue configuration set: %d\n",
 			       bp->num_queues);
-	} else if (rc > 0) {
-		/* Get by with single vector */
-		rc = pci_enable_msix(bp->pdev, &bp->msix_table[0], 1);
-		if (rc) {
-			BNX2X_DEV_INFO("Single MSI-X is not attainable rc %d\n",
-				       rc);
-			goto no_msix;
-		}
-
-		BNX2X_DEV_INFO("Using single MSI-X vector\n");
-		bp->flags |= USING_SINGLE_MSIX_FLAG;
-
-		BNX2X_DEV_INFO("set number of queues to 1\n");
-		bp->num_ethernet_queues = 1;
-		bp->num_queues = bp->num_ethernet_queues + bp->num_cnic_queues;
-	} else if (rc < 0) {
-		BNX2X_DEV_INFO("MSI-X is not attainable  rc %d\n", rc);
-		goto no_msix;
-	}
 
 	bp->flags |= USING_MSIX_FLAG;
 
 	return 0;
 
 no_msix:
+	BNX2X_DEV_INFO("MSI-X is not attainable rc %d\n", rc);
+
 	/* fall to INTx if not enough memory */
 	if (rc == -ENOMEM)
 		bp->flags |= DISABLE_MSI_FLAG;
-- 
1.7.7.6

[PATCH RFC 15/77] bnx2: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/broadcom/bnx2.c |   27 ++++++++++++++-------------
 1 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2.c b/drivers/net/ethernet/broadcom/bnx2.c
index e838a3f..c902627 100644
--- a/drivers/net/ethernet/broadcom/bnx2.c
+++ b/drivers/net/ethernet/broadcom/bnx2.c
@@ -6202,25 +6202,26 @@ bnx2_enable_msix(struct bnx2 *bp, int msix_vecs)
 	 *  is setup properly */
 	BNX2_RD(bp, BNX2_PCI_MSIX_CONTROL);
 
-	for (i = 0; i < BNX2_MAX_MSIX_VEC; i++) {
-		msix_ent[i].entry = i;
-		msix_ent[i].vector = 0;
-	}
-
 	total_vecs = msix_vecs;
 #ifdef BCM_CNIC
 	total_vecs++;
 #endif
-	rc = -ENOSPC;
-	while (total_vecs >= BNX2_MIN_MSIX_VEC) {
-		rc = pci_enable_msix(bp->pdev, msix_ent, total_vecs);
-		if (rc <= 0)
-			break;
-		if (rc > 0)
-			total_vecs = rc;
+	rc = pci_msix_table_size(bp->pdev);
+	if (rc < 0)
+		return;
+
+	total_vecs = min(total_vecs, rc);
+	if (total_vecs < BNX2_MIN_MSIX_VEC)
+		return;
+
+	BUG_ON(total_vecs > ARRAY_SIZE(msix_ent));
+	for (i = 0; i < total_vecs; i++) {
+		msix_ent[i].entry = i;
+		msix_ent[i].vector = 0;
 	}
 
-	if (rc != 0)
+	rc = pci_enable_msix(bp->pdev, msix_ent, total_vecs);
+	if (rc)
 		return;
 
 	msix_vecs = total_vecs;
-- 
1.7.7.6

[PATCH RFC 16/77] cciss: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/block/cciss.c |   17 +++++++----------
 1 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index d2d95ff..80068a0 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4079,7 +4079,11 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 		goto default_int_mode;
 
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
-		err = pci_enable_msix(h->pdev, cciss_msix_entries, 4);
+		err = pci_msix_table_size(h->pdev);
+		if (err < ARRAY_SIZE(cciss_msix_entries))
+			goto default_int_mode;
+		err = pci_enable_msix(h->pdev, cciss_msix_entries,
+				      ARRAY_SIZE(cciss_msix_entries));
 		if (!err) {
 			h->intr[0] = cciss_msix_entries[0].vector;
 			h->intr[1] = cciss_msix_entries[1].vector;
@@ -4088,15 +4092,8 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 			h->msix_vector = 1;
 			return;
 		}
-		if (err > 0) {
-			dev_warn(&h->pdev->dev,
-				"only %d MSI-X vectors available\n", err);
-			goto default_int_mode;
-		} else {
-			dev_warn(&h->pdev->dev,
-				"MSI-X init failed %d\n", err);
-			goto default_int_mode;
-		}
+		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
+		goto default_int_mode;
 	}
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		if (!pci_enable_msi(h->pdev))
-- 
1.7.7.6

[PATCH RFC 17/77] cciss: Update a misleading comment on interrupt usage

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/block/cciss.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 80068a0..bf11540 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4103,7 +4103,10 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 	}
 default_int_mode:
 #endif				/* CONFIG_PCI_MSI */
-	/* if we get here we're going to use the default interrupt mode */
+	/*
+	 * If we get here we're going to use either the
+	 * default interrupt mode or single MSI mode
+	 */
 	h->intr[h->intr_mode] = h->pdev->irq;
 	return;
 }
-- 
1.7.7.6

[PATCH RFC 18/77] cciss: Fallback to single MSI mode in case MSI-X failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/block/cciss.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index bf11540..0eea035 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4081,7 +4081,7 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
 		err = pci_msix_table_size(h->pdev);
 		if (err < ARRAY_SIZE(cciss_msix_entries))
-			goto default_int_mode;
+			goto single_msi_mode;
 		err = pci_enable_msix(h->pdev, cciss_msix_entries,
 				      ARRAY_SIZE(cciss_msix_entries));
 		if (!err) {
@@ -4093,8 +4093,8 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 			return;
 		}
 		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
-		goto default_int_mode;
 	}
+single_msi_mode:
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		if (!pci_enable_msi(h->pdev))
 			h->msi_vector = 1;
-- 
1.7.7.6

[PATCH RFC 19/77] csiostor: Do not call pci_disable_msix() if pci_enable_msix() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/csiostor/csio_isr.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_isr.c b/drivers/scsi/csiostor/csio_isr.c
index 7ee9777..91ba91d 100644
--- a/drivers/scsi/csiostor/csio_isr.c
+++ b/drivers/scsi/csiostor/csio_isr.c
@@ -529,10 +529,8 @@ csio_enable_msix(struct csio_hw *hw)
 			csio_reduce_sqsets(hw, cnt - extra);
 		}
 	} else {
-		if (rv > 0) {
-			pci_disable_msix(hw->pdev);
+		if (rv > 0)
 			csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
-		}
 
 		kfree(entries);
 		return -ENOMEM;
-- 
1.7.7.6

[PATCH RFC 20/77] csiostor: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/csiostor/csio_isr.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_isr.c b/drivers/scsi/csiostor/csio_isr.c
index 91ba91d..abf20ab 100644
--- a/drivers/scsi/csiostor/csio_isr.c
+++ b/drivers/scsi/csiostor/csio_isr.c
@@ -533,7 +533,7 @@ csio_enable_msix(struct csio_hw *hw)
 			csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
 
 		kfree(entries);
-		return -ENOMEM;
+		return -ENOSPC;
 	}
 
 	/* Save off vectors */
-- 
1.7.7.6

[PATCH RFC 21/77] csiostor: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/csiostor/csio_isr.c |   18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_isr.c b/drivers/scsi/csiostor/csio_isr.c
index abf20ab..b8a840e 100644
--- a/drivers/scsi/csiostor/csio_isr.c
+++ b/drivers/scsi/csiostor/csio_isr.c
@@ -512,6 +512,16 @@ csio_enable_msix(struct csio_hw *hw)
 	if (hw->flags & CSIO_HWF_USING_SOFT_PARAMS || !csio_is_hw_master(hw))
 		cnt = min_t(uint8_t, hw->cfg_niq, cnt);
 
+	rv = pci_msix_table_size(hw->pdev);
+	if (rv < 0)
+		return rv;
+
+	cnt = min(cnt, rv);
+	if (cnt < min) {
+		csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
+		return -ENOSPC;
+	}
+
 	entries = kzalloc(sizeof(struct msix_entry) * cnt, GFP_KERNEL);
 	if (!entries)
 		return -ENOMEM;
@@ -521,19 +531,15 @@ csio_enable_msix(struct csio_hw *hw)
 
 	csio_dbg(hw, "FW supp #niq:%d, trying %d msix's\n", hw->cfg_niq, cnt);
 
-	while ((rv = pci_enable_msix(hw->pdev, entries, cnt)) >= min)
-		cnt = rv;
+	rv = pci_enable_msix(hw->pdev, entries, cnt);
 	if (!rv) {
 		if (cnt < (hw->num_sqsets + extra)) {
 			csio_dbg(hw, "Reducing sqsets to %d\n", cnt - extra);
 			csio_reduce_sqsets(hw, cnt - extra);
 		}
 	} else {
-		if (rv > 0)
-			csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
-
 		kfree(entries);
-		return -ENOSPC;
+		return rv;
 	}
 
 	/* Save off vectors */
-- 
1.7.7.6

[PATCH RFC 22/77] cxgb3: Do not call pci_disable_msix() if pci_enable_msix() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
index b650951..9bd3099 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
@@ -3097,9 +3097,6 @@ static int cxgb_enable_msix(struct adapter *adap)
 	while ((err = pci_enable_msix(adap->pdev, entries, vectors)) > 0)
 		vectors = err;
 
-	if (err < 0)
-		pci_disable_msix(adap->pdev);
-
 	if (!err && vectors < (adap->params.nports + 1)) {
 		pci_disable_msix(adap->pdev);
 		err = -1;
-- 
1.7.7.6

[PATCH RFC 23/77] cxgb3: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
index 9bd3099..915729c 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
@@ -3099,7 +3099,7 @@ static int cxgb_enable_msix(struct adapter *adap)
 
 	if (!err && vectors < (adap->params.nports + 1)) {
 		pci_disable_msix(adap->pdev);
-		err = -1;
+		err = -ENOSPC;
 	}
 
 	if (!err) {
-- 
1.7.7.6

[PATCH RFC 24/77] cxgb3: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c |   29 ++++++++++++-----------
 1 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
index 915729c..bf14fd6 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
@@ -3090,25 +3090,26 @@ static int cxgb_enable_msix(struct adapter *adap)
 	int vectors;
 	int i, err;
 
-	vectors = ARRAY_SIZE(entries);
+	err = pci_msix_table_size(adap->pdev);
+	if (err < 0)
+		return err;
+
+	vectors = min_t(int, err, ARRAY_SIZE(entries));
+	if (vectors < (adap->params.nports + 1))
+		return -ENOSPC;
+
 	for (i = 0; i < vectors; ++i)
 		entries[i].entry = i;
 
-	while ((err = pci_enable_msix(adap->pdev, entries, vectors)) > 0)
-		vectors = err;
-
-	if (!err && vectors < (adap->params.nports + 1)) {
-		pci_disable_msix(adap->pdev);
-		err = -ENOSPC;
-	}
+	err = pci_enable_msix(adap->pdev, entries, vectors);
+	if (err)
+		return err;
 
-	if (!err) {
-		for (i = 0; i < vectors; ++i)
-			adap->msix_info[i].vec = entries[i].vector;
-		adap->msix_nvectors = vectors;
-	}
+	for (i = 0; i < vectors; ++i)
+		adap->msix_info[i].vec = entries[i].vector;
+	adap->msix_nvectors = vectors;
 
-	return err;
+	return 0;
 }
 
 static void print_port_info(struct adapter *adap, const struct adapter_info *ai)
-- 
1.7.7.6

[PATCH RFC 25/77] cxgb4: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index c73cabd..9425bc6 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -5732,9 +5732,11 @@ static int enable_msix(struct adapter *adap)
 		}
 		for (i = 0; i < want; ++i)
 			adap->msix_info[i].vec = entries[i].vector;
-	} else if (err > 0)
+	} else if (err > 0) {
 		dev_info(adap->pdev_dev,
 			 "only %d MSI-X vectors left, not using MSI-X\n", err);
+		err = -ENOSPC;
+	}
 	return err;
 }
 
-- 
1.7.7.6

[PATCH RFC 26/77] cxgb4: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c |   62 +++++++++++++----------
 1 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 9425bc6..e5fbbd3 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -5699,9 +5699,6 @@ static int enable_msix(struct adapter *adap)
 	unsigned int nchan = adap->params.nports;
 	struct msix_entry entries[MAX_INGQ + 1];
 
-	for (i = 0; i < ARRAY_SIZE(entries); ++i)
-		entries[i].entry = i;
-
 	want = s->max_ethqsets + EXTRA_VECS;
 	if (is_offload(adap)) {
 		want += s->rdmaqs + s->ofldqsets;
@@ -5710,34 +5707,45 @@ static int enable_msix(struct adapter *adap)
 	}
 	need = adap->params.nports + EXTRA_VECS + ofld_need;
 
-	while ((err = pci_enable_msix(adap->pdev, entries, want)) >= need)
-		want = err;
+	err = pci_msix_table_size(adap->pdev);
+	if (err < 0)
+		return err;
 
-	if (!err) {
-		/*
-		 * Distribute available vectors to the various queue groups.
-		 * Every group gets its minimum requirement and NIC gets top
-		 * priority for leftovers.
-		 */
-		i = want - EXTRA_VECS - ofld_need;
-		if (i < s->max_ethqsets) {
-			s->max_ethqsets = i;
-			if (i < s->ethqsets)
-				reduce_ethqs(adap, i);
-		}
-		if (is_offload(adap)) {
-			i = want - EXTRA_VECS - s->max_ethqsets;
-			i -= ofld_need - nchan;
-			s->ofldqsets = (i / nchan) * nchan;  /* round down */
-		}
-		for (i = 0; i < want; ++i)
-			adap->msix_info[i].vec = entries[i].vector;
-	} else if (err > 0) {
+	want = min(want, err);
+	if (want < need) {
 		dev_info(adap->pdev_dev,
 			 "only %d MSI-X vectors left, not using MSI-X\n", err);
-		err = -ENOSPC;
+		return -ENOSPC;
 	}
-	return err;
+
+	BUG_ON(want > ARRAY_SIZE(entries));
+	for (i = 0; i < want; ++i)
+		entries[i].entry = i;
+
+	err = pci_enable_msix(adap->pdev, entries, want);
+	if (err)
+		return err;
+
+	/*
+	 * Distribute available vectors to the various queue groups.
+	 * Every group gets its minimum requirement and NIC gets top
+	 * priority for leftovers.
+	 */
+	i = want - EXTRA_VECS - ofld_need;
+	if (i < s->max_ethqsets) {
+		s->max_ethqsets = i;
+		if (i < s->ethqsets)
+			reduce_ethqs(adap, i);
+	}
+	if (is_offload(adap)) {
+		i = want - EXTRA_VECS - s->max_ethqsets;
+		i -= ofld_need - nchan;
+		s->ofldqsets = (i / nchan) * nchan;  /* round down */
+	}
+	for (i = 0; i < want; ++i)
+		adap->msix_info[i].vec = entries[i].vector;
+
+	return 0;
 }
 
 #undef EXTRA_VECS
-- 
1.7.7.6

[PATCH RFC 27/77] cxgb4vf: Do not call pci_disable_msix() if pci_enable_msix() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 .../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c    |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index 40c22e7..87a82fc 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -2468,7 +2468,6 @@ static int enable_msix(struct adapter *adapter)
 		for (i = 0; i < want; ++i)
 			adapter->msix_info[i].vec = entries[i].vector;
 	} else if (err > 0) {
-		pci_disable_msix(adapter->pdev);
 		dev_info(adapter->pdev_dev, "only %d MSI-X vectors left,"
 			 " not using MSI-X\n", err);
 	}
-- 
1.7.7.6

[PATCH RFC 28/77] cxgb4vf: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 .../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c    |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index 87a82fc..11cbce1 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -2470,6 +2470,7 @@ static int enable_msix(struct adapter *adapter)
 	} else if (err > 0) {
 		dev_info(adapter->pdev_dev, "only %d MSI-X vectors left,"
 			 " not using MSI-X\n", err);
+		err = -ENOSPC;
 	}
 	return err;
 }
-- 
1.7.7.6

[PATCH RFC 29/77] cxgb4vf: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 .../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c    |   49 ++++++++++++--------
 1 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index 11cbce1..48bb33b 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -2437,13 +2437,10 @@ static void reduce_ethqs(struct adapter *adapter, int n)
  */
 static int enable_msix(struct adapter *adapter)
 {
-	int i, err, want, need;
+	int i, err, want, need, nqsets;
 	struct msix_entry entries[MSIX_ENTRIES];
 	struct sge *s = &adapter->sge;
 
-	for (i = 0; i < MSIX_ENTRIES; ++i)
-		entries[i].entry = i;
-
 	/*
 	 * We _want_ enough MSI-X interrupts to cover all of our "Queue Sets"
 	 * plus those needed for our "extras" (for example, the firmware
@@ -2453,26 +2450,38 @@ static int enable_msix(struct adapter *adapter)
 	 */
 	want = s->max_ethqsets + MSIX_EXTRAS;
 	need = adapter->params.nports + MSIX_EXTRAS;
-	while ((err = pci_enable_msix(adapter->pdev, entries, want)) >= need)
-		want = err;
 
-	if (err == 0) {
-		int nqsets = want - MSIX_EXTRAS;
-		if (nqsets < s->max_ethqsets) {
-			dev_warn(adapter->pdev_dev, "only enough MSI-X vectors"
-				 " for %d Queue Sets\n", nqsets);
-			s->max_ethqsets = nqsets;
-			if (nqsets < s->ethqsets)
-				reduce_ethqs(adapter, nqsets);
-		}
-		for (i = 0; i < want; ++i)
-			adapter->msix_info[i].vec = entries[i].vector;
-	} else if (err > 0) {
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		return err;
+
+	want = min(want, err);
+	if (want < need) {
 		dev_info(adapter->pdev_dev, "only %d MSI-X vectors left,"
 			 " not using MSI-X\n", err);
-		err = -ENOSPC;
+		return -ENOSPC;
 	}
-	return err;
+
+	BUG_ON(want > ARRAY_SIZE(entries));
+	for (i = 0; i < want; ++i)
+		entries[i].entry = i;
+
+	err = pci_enable_msix(adapter->pdev, entries, want);
+	if (err)
+		return err;
+
+	nqsets = want - MSIX_EXTRAS;
+	if (nqsets < s->max_ethqsets) {
+		dev_warn(adapter->pdev_dev, "only enough MSI-X vectors"
+			 " for %d Queue Sets\n", nqsets);
+		s->max_ethqsets = nqsets;
+		if (nqsets < s->ethqsets)
+			reduce_ethqs(adapter, nqsets);
+	}
+	for (i = 0; i < want; ++i)
+		adapter->msix_info[i].vec = entries[i].vector;
+
+	return 0;
 }
 
 static const struct net_device_ops cxgb4vf_netdev_ops	= {
-- 
1.7.7.6

[PATCH RFC 30/77] hpsa: Update a misleading comment on interrupt usage

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/hpsa.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 891c86b..393c8db 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -4141,7 +4141,11 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 	}
 default_int_mode:
 #endif				/* CONFIG_PCI_MSI */
-	/* if we get here we're going to use the default interrupt mode */
+	/*
+	 * If we get here we're going to use either the
+	 * default interrupt mode or single MSI mode
+	 */
+
 	h->intr[h->intr_mode] = h->pdev->irq;
 }
 
-- 
1.7.7.6

[PATCH RFC 31/77] hpsa: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/hpsa.c |   28 +++++++++++++---------------
 1 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 393c8db..eb17b3d 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -4103,34 +4103,32 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 	int err, i;
 	struct msix_entry hpsa_msix_entries[MAX_REPLY_QUEUES];
 
-	for (i = 0; i < MAX_REPLY_QUEUES; i++) {
-		hpsa_msix_entries[i].vector = 0;
-		hpsa_msix_entries[i].entry = i;
-	}
-
 	/* Some boards advertise MSI but don't really support it */
 	if ((h->board_id == 0x40700E11) || (h->board_id == 0x40800E11) ||
 	    (h->board_id == 0x40820E11) || (h->board_id == 0x40830E11))
 		goto default_int_mode;
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
 		dev_info(&h->pdev->dev, "MSIX\n");
+
+		err = pci_msix_table_size(h->pdev);
+		if (err < ARRAY_SIZE(hpsa_msix_entries))
+			goto default_int_mode;
+
+		for (i = 0; i < ARRAY_SIZE(hpsa_msix_entries); i++) {
+			hpsa_msix_entries[i].vector = 0;
+			hpsa_msix_entries[i].entry = i;
+		}
+
 		err = pci_enable_msix(h->pdev, hpsa_msix_entries,
-						MAX_REPLY_QUEUES);
+				      ARRAY_SIZE(hpsa_msix_entries));
 		if (!err) {
 			for (i = 0; i < MAX_REPLY_QUEUES; i++)
 				h->intr[i] = hpsa_msix_entries[i].vector;
 			h->msix_vector = 1;
 			return;
 		}
-		if (err > 0) {
-			dev_warn(&h->pdev->dev, "only %d MSI-X vectors "
-			       "available\n", err);
-			goto default_int_mode;
-		} else {
-			dev_warn(&h->pdev->dev, "MSI-X init failed %d\n",
-			       err);
-			goto default_int_mode;
-		}
+		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
+		goto default_int_mode;
 	}
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		dev_info(&h->pdev->dev, "MSI\n");
-- 
1.7.7.6

[PATCH RFC 32/77] hpsa: Fallback to single MSI mode in case MSI-X failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/hpsa.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index eb17b3d..252b65d 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -4112,7 +4112,7 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 
 		err = pci_msix_table_size(h->pdev);
 		if (err < ARRAY_SIZE(hpsa_msix_entries))
-			goto default_int_mode;
+			goto single_msi_mode;
 
 		for (i = 0; i < ARRAY_SIZE(hpsa_msix_entries); i++) {
 			hpsa_msix_entries[i].vector = 0;
@@ -4128,8 +4128,9 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 			return;
 		}
 		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
-		goto default_int_mode;
+		goto single_msi_mode;
 	}
+single_msi_mode:
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		dev_info(&h->pdev->dev, "MSI\n");
 		if (!pci_enable_msi(h->pdev))
-- 
1.7.7.6

[PATCH RFC 33/77] ioat: Disable MSI-X in case request of IRQ failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/dma/ioat/dma.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 5ff6fc1..acee3b2 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -937,6 +937,7 @@ msix:
 				chan = ioat_chan_by_index(device, j);
 				devm_free_irq(dev, msix->vector, chan);
 			}
+			pci_disable_msix(pdev);
 			goto msix_single_vector;
 		}
 	}
-- 
1.7.7.6

[PATCH RFC 34/77] ioat: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/dma/ioat/dma.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index acee3b2..b352ee6 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -915,15 +915,19 @@ int ioat_dma_setup_interrupts(struct ioatdma_device *device)
 
 msix:
 	/* The number of MSI-X vectors should equal the number of channels */
+	err = pci_msix_table_size(pdev);
+	if (err < 0)
+		goto msi;
+	if (err < device->common.chancnt)
+		goto msix_single_vector;
+
 	msixcnt = device->common.chancnt;
 	for (i = 0; i < msixcnt; i++)
 		device->msix_entries[i].entry = i;
 
 	err = pci_enable_msix(pdev, device->msix_entries, msixcnt);
-	if (err < 0)
+	if (err)
 		goto msi;
-	if (err > 0)
-		goto msix_single_vector;
 
 	for (i = 0; i < msixcnt; i++) {
 		msix = &device->msix_entries[i];
-- 
1.7.7.6

[PATCH RFC 35/77] ipr: Do not call pci_disable_msi/msix() if pci_enable_msi/msix() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/ipr.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 36ac1c3..fb57e21 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -9255,10 +9255,8 @@ static int ipr_enable_msix(struct ipr_ioa_cfg *ioa_cfg)
 	while ((err = pci_enable_msix(ioa_cfg->pdev, entries, vectors)) > 0)
 			vectors = err;
 
-	if (err < 0) {
-		pci_disable_msix(ioa_cfg->pdev);
+	if (err < 0)
 		return err;
-	}
 
 	if (!err) {
 		for (i = 0; i < vectors; i++)
@@ -9278,10 +9276,8 @@ static int ipr_enable_msi(struct ipr_ioa_cfg *ioa_cfg)
 	while ((err = pci_enable_msi_block(ioa_cfg->pdev, vectors)) > 0)
 			vectors = err;
 
-	if (err < 0) {
-		pci_disable_msi(ioa_cfg->pdev);
+	if (err < 0)
 		return err;
-	}
 
 	if (!err) {
 		for (i = 0; i < vectors; i++)
-- 
1.7.7.6

[PATCH RFC 36/77] ipr: Enable MSI-X when IPR_USE_MSIX type is set, not IPR_USE_MSI

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/ipr.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index fb57e21..762a93e 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -9527,7 +9527,7 @@ static int ipr_probe_ioa(struct pci_dev *pdev,
 		ipr_number_of_msix = IPR_MAX_MSIX_VECTORS;
 	}
 
-	if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSI &&
+	if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSIX &&
 			ipr_enable_msix(ioa_cfg) == 0)
 		ioa_cfg->intr_flag = IPR_USE_MSIX;
 	else if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSI &&
-- 
1.7.7.6

Re: [PATCH RFC 36/77] ipr: Enable MSI-X when IPR_USE_MSIX type is set, not IPR_USE_MSI

[Brian King]

On 10/02/2013 05:48 AM, Alexander Gordeev wrote:
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/scsi/ipr.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
> index fb57e21..762a93e 100644
> --- a/drivers/scsi/ipr.c
> +++ b/drivers/scsi/ipr.c
> @@ -9527,7 +9527,7 @@ static int ipr_probe_ioa(struct pci_dev *pdev,
>  		ipr_number_of_msix = IPR_MAX_MSIX_VECTORS;
>  	}
> 
> -	if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSI &&
> +	if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSIX &&
>  			ipr_enable_msix(ioa_cfg) == 0)
>  		ioa_cfg->intr_flag = IPR_USE_MSIX;
>  	else if (ioa_cfg->ipr_chip->intr_type == IPR_USE_MSI &&
> 

Nack. ioa_cfg->ipr_chip->intr_type gets initialized from the ipr_chip table
at the top of the driver which never sets intr_type to IPR_USE_MSIX, so this
will break MSI-X support for ipr. 

We indicate at the chip level only whether we want to force LSI or whether
we want to enable MSI / MSI-X and then try enabling MSI-X and fall back to
MSI if MSI-X is not available or does not work. We then set intr_flag to indicate
what we are actually using on the specific adapter.

Thanks,

Brian

-- 
Brian King
Power Linux I/O
IBM Linux Technology Center

[PATCH RFC 37/77] ipr: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/ipr.c |   46 +++++++++++++++++++++++-----------------------
 1 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 762a93e..86ed0a2 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -9247,45 +9247,45 @@ static int ipr_enable_msix(struct ipr_ioa_cfg *ioa_cfg)
 	struct msix_entry entries[IPR_MAX_MSIX_VECTORS];
 	int i, err, vectors;
 
-	for (i = 0; i < ARRAY_SIZE(entries); ++i)
-		entries[i].entry = i;
+	err = pci_msix_table_size(ioa_cfg->pdev);
+	if (err < 0)
+		return err;
 
-	vectors = ipr_number_of_msix;
+	vectors = min_t(int, err, ipr_number_of_msix);
 
-	while ((err = pci_enable_msix(ioa_cfg->pdev, entries, vectors)) > 0)
-			vectors = err;
+	BUG_ON(vectors > ARRAY_SIZE(entries));
+	for (i = 0; i < vectors; ++i)
+		entries[i].entry = i;
 
-	if (err < 0)
+	err = pci_enable_msix(ioa_cfg->pdev, entries, vectors);
+	if (err)
 		return err;
 
-	if (!err) {
-		for (i = 0; i < vectors; i++)
-			ioa_cfg->vectors_info[i].vec = entries[i].vector;
-		ioa_cfg->nvectors = vectors;
-	}
+	for (i = 0; i < vectors; i++)
+		ioa_cfg->vectors_info[i].vec = entries[i].vector;
+	ioa_cfg->nvectors = vectors;
 
-	return err;
+	return 0;
 }
 
 static int ipr_enable_msi(struct ipr_ioa_cfg *ioa_cfg)
 {
 	int i, err, vectors;
 
-	vectors = ipr_number_of_msix;
-
-	while ((err = pci_enable_msi_block(ioa_cfg->pdev, vectors)) > 0)
-			vectors = err;
-
+	err = pci_get_msi_cap(ioa_cfg->pdev);
 	if (err < 0)
 		return err;
 
-	if (!err) {
-		for (i = 0; i < vectors; i++)
-			ioa_cfg->vectors_info[i].vec = ioa_cfg->pdev->irq + i;
-		ioa_cfg->nvectors = vectors;
-	}
+	vectors = min_t(int, err, ipr_number_of_msix);
+	err = pci_enable_msi_block(ioa_cfg->pdev, vectors);
+	if (err)
+		return err;
+
+	for (i = 0; i < vectors; i++)
+		ioa_cfg->vectors_info[i].vec = ioa_cfg->pdev->irq + i;
+	ioa_cfg->nvectors = vectors;
 
-	return err;
+	return 0;
 }
 
 static void name_msi_vectors(struct ipr_ioa_cfg *ioa_cfg)
-- 
1.7.7.6

[PATCH RFC 38/77] ixgbe: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c |   62 +++++++++++++------------
 1 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index 90b4e10..2444a4d 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -711,37 +711,39 @@ static void ixgbe_acquire_msix_vectors(struct ixgbe_adapter *adapter,
 	 * Right now, we simply care about how many we'll get; we'll
 	 * set them up later while requesting irq's.
 	 */
-	while (vectors >= vector_threshold) {
-		err = pci_enable_msix(adapter->pdev, adapter->msix_entries,
-				      vectors);
-		if (!err) /* Success in acquiring all requested vectors. */
-			break;
-		else if (err < 0)
-			vectors = 0; /* Nasty failure, quit now */
-		else /* err == number of vectors we should try again with */
-			vectors = err;
-	}
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		goto err_alloc_msix;
 
-	if (vectors < vector_threshold) {
-		/* Can't allocate enough MSI-X interrupts?  Oh well.
-		 * This just means we'll go with either a single MSI
-		 * vector or fall back to legacy interrupts.
-		 */
-		netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
-			     "Unable to allocate MSI-X interrupts\n");
-		adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
-		kfree(adapter->msix_entries);
-		adapter->msix_entries = NULL;
-	} else {
-		adapter->flags |= IXGBE_FLAG_MSIX_ENABLED; /* Woot! */
-		/*
-		 * Adjust for only the vectors we'll use, which is minimum
-		 * of max_msix_q_vectors + NON_Q_VECTORS, or the number of
-		 * vectors we were allocated.
-		 */
-		vectors -= NON_Q_VECTORS;
-		adapter->num_q_vectors = min(vectors, adapter->max_q_vectors);
-	}
+	vectors = min(vectors, err);
+	if (vectors < vector_threshold)
+		goto err_alloc_msix;
+
+	err = pci_enable_msix(adapter->pdev, adapter->msix_entries, vectors);
+	if (err)
+		goto err_alloc_msix;
+
+	adapter->flags |= IXGBE_FLAG_MSIX_ENABLED; /* Woot! */
+	/*
+	 * Adjust for only the vectors we'll use, which is minimum
+	 * of max_msix_q_vectors + NON_Q_VECTORS, or the number of
+	 * vectors we were allocated.
+	 */
+	vectors -= NON_Q_VECTORS;
+	adapter->num_q_vectors = min(vectors, adapter->max_q_vectors);
+
+	return;
+
+err_alloc_msix:
+	/* Can't allocate enough MSI-X interrupts?  Oh well.
+	 * This just means we'll go with either a single MSI
+	 * vector or fall back to legacy interrupts.
+	 */
+	netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
+		     "Unable to allocate MSI-X interrupts\n");
+	adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
+	kfree(adapter->msix_entries);
+	adapter->msix_entries = NULL;
 }
 
 static void ixgbe_add_ring(struct ixgbe_ring *ring,
-- 
1.7.7.6

[PATCH RFC 39/77] ixgbevf: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 59a62bb..fa0537a 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -1773,7 +1773,7 @@ static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 	}
 
 	if (vectors < vector_threshold)
-		err = -ENOMEM;
+		err = -ENOSPC;
 
 	if (err) {
 		dev_err(&adapter->pdev->dev,
-- 
1.7.7.6

[PATCH RFC 40/77] ixgbevf: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   18 +++++++-----------
 1 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index fa0537a..d506a01 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -1749,8 +1749,7 @@ void ixgbevf_reset(struct ixgbevf_adapter *adapter)
 static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 					int vectors)
 {
-	int err = 0;
-	int vector_threshold;
+	int err, vector_threshold;
 
 	/* We'll want at least 2 (vector_threshold):
 	 * 1) TxQ[0] + RxQ[0] handler
@@ -1763,18 +1762,15 @@ static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 	 * Right now, we simply care about how many we'll get; we'll
 	 * set them up later while requesting irq's.
 	 */
-	while (vectors >= vector_threshold) {
-		err = pci_enable_msix(adapter->pdev, adapter->msix_entries,
-				      vectors);
-		if (!err || err < 0) /* Success or a nasty failure. */
-			break;
-		else /* err == number of vectors we should try again with */
-			vectors = err;
-	}
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		return err;
 
+	vectors = min(vectors, err);
 	if (vectors < vector_threshold)
-		err = -ENOSPC;
+		return -ENOSPC;
 
+	err = pci_enable_msix(adapter->pdev, adapter->msix_entries, vectors);
 	if (err) {
 		dev_err(&adapter->pdev->dev,
 			"Unable to allocate MSI-X interrupts\n");
-- 
1.7.7.6

Re: [PATCH RFC 40/77] ixgbevf: Update MSI/MSI-X interrupts enablement code

[Keller, Jacob E]

On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   18 +++++++-----------
>  1 files changed, 7 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> index fa0537a..d506a01 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> @@ -1749,8 +1749,7 @@ void ixgbevf_reset(struct ixgbevf_adapter *adapter)
>  static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
>  					int vectors)
>  {
> -	int err = 0;
> -	int vector_threshold;
> +	int err, vector_threshold;
>  
>  	/* We'll want at least 2 (vector_threshold):
>  	 * 1) TxQ[0] + RxQ[0] handler
> @@ -1763,18 +1762,15 @@ static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
>  	 * Right now, we simply care about how many we'll get; we'll
>  	 * set them up later while requesting irq's.
>  	 */
> -	while (vectors >= vector_threshold) {
> -		err = pci_enable_msix(adapter->pdev, adapter->msix_entries,
> -				      vectors);
> -		if (!err || err < 0) /* Success or a nasty failure. */
> -			break;
> -		else /* err == number of vectors we should try again with */
> -			vectors = err;
> -	}
> +	err = pci_msix_table_size(adapter->pdev);
I would prefer to use something other than "err" here since the value
isn't really an error if it's greater than 0. However, it's not really a
big issue, since you immediately conver to using vectors on the next
line of code.. I think its alright overall.

Regards,
Jake

> +	if (err < 0)
> +		return err;
>  
> +	vectors = min(vectors, err);
>  	if (vectors < vector_threshold)
> -		err = -ENOSPC;
> +		return -ENOSPC;
>  
> +	err = pci_enable_msix(adapter->pdev, adapter->msix_entries, vectors);
>  	if (err) {
>  		dev_err(&adapter->pdev->dev,
>  			"Unable to allocate MSI-X interrupts\n");

[PATCH RFC 41/77] lpfc: Do not call pci_disable_msix() if pci_enable_msix() failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/lpfc/lpfc_init.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 647f5bf..0803b84 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -8080,7 +8080,7 @@ lpfc_sli_enable_msix(struct lpfc_hba *phba)
 	if (rc) {
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
 				"0420 PCI enable MSI-X failed (%d)\n", rc);
-		goto msi_fail_out;
+		goto vec_fail_out;
 	}
 	for (i = 0; i < LPFC_MSIX_VECTORS; i++)
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
@@ -8158,6 +8158,8 @@ irq_fail_out:
 msi_fail_out:
 	/* Unconfigure MSI-X capability structure */
 	pci_disable_msix(phba->pcidev);
+
+vec_fail_out:
 	return rc;
 }
 
@@ -8646,7 +8648,7 @@ enable_msix_vectors:
 	} else if (rc) {
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
 				"0484 PCI enable MSI-X failed (%d)\n", rc);
-		goto msi_fail_out;
+		goto vec_fail_out;
 	}
 
 	/* Log MSI-X vector assignment */
@@ -8698,9 +8700,10 @@ cfg_fail_out:
 			 &phba->sli4_hba.fcp_eq_hdl[index]);
 	}
 
-msi_fail_out:
 	/* Unconfigure MSI-X capability structure */
 	pci_disable_msix(phba->pcidev);
+
+vec_fail_out:
 	return rc;
 }
 
-- 
1.7.7.6

[PATCH RFC 42/77] lpfc: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Note, in case just one MSI-X vector was available the
error message "0484 PCI enable MSI-X failed 1" is
preserved to not break tools which might depend on it.

Also, not sure why in case of multiple MSI-Xs mode failed
the driver skips the single MSI-X mode and falls back to
single MSI mode.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/lpfc/lpfc_init.c |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 0803b84..d83a1a3 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -8639,13 +8639,17 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 
 	/* Configure MSI-X capability structure */
 	vectors = phba->cfg_fcp_io_channel;
-enable_msix_vectors:
-	rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
-			     vectors);
-	if (rc > 1) {
-		vectors = rc;
-		goto enable_msix_vectors;
-	} else if (rc) {
+
+	rc = pci_msix_table_size(phba->pcidev);
+	if (rc < 0)
+		goto msg_fail_out;
+
+	vectors = min(vectors, rc);
+	if (vectors > 1)
+		rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
+				     vectors);
+	if (rc) {
+msg_fail_out:
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
 				"0484 PCI enable MSI-X failed (%d)\n", rc);
 		goto vec_fail_out;
-- 
1.7.7.6

[PATCH RFC 43/77] lpfc: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/lpfc/lpfc_init.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index d83a1a3..0ec8008 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -8645,9 +8645,13 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 		goto msg_fail_out;
 
 	vectors = min(vectors, rc);
-	if (vectors > 1)
-		rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
-				     vectors);
+	if (vectors < 2) {
+		rc = -ENOSPC;
+		goto msg_fail_out;
+	}
+
+	rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
+			     vectors);
 	if (rc) {
 msg_fail_out:
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
-- 
1.7.7.6

[PATCH RFC 44/77] lpfc: Make MSI-X initialization routine more readable

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/lpfc/lpfc_init.c |   23 +++++++++++------------
 1 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 0ec8008..0cfaf20 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -8633,10 +8633,6 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 {
 	int vectors, rc, index;
 
-	/* Set up MSI-X multi-message vectors */
-	for (index = 0; index < phba->cfg_fcp_io_channel; index++)
-		phba->sli4_hba.msix_entries[index].entry = index;
-
 	/* Configure MSI-X capability structure */
 	vectors = phba->cfg_fcp_io_channel;
 
@@ -8650,14 +8646,14 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 		goto msg_fail_out;
 	}
 
+	/* Set up MSI-X multi-message vectors */
+	for (index = 0; index < vectors; index++)
+		phba->sli4_hba.msix_entries[index].entry = index;
+
 	rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
 			     vectors);
-	if (rc) {
-msg_fail_out:
-		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
-				"0484 PCI enable MSI-X failed (%d)\n", rc);
-		goto vec_fail_out;
-	}
+	if (rc)
+		goto msg_fail_out;
 
 	/* Log MSI-X vector assignment */
 	for (index = 0; index < vectors; index++)
@@ -8697,7 +8693,7 @@ msg_fail_out:
 	}
 
 	lpfc_sli4_set_affinity(phba, vectors);
-	return rc;
+	return 0;
 
 cfg_fail_out:
 	/* free the irq already requested */
@@ -8710,8 +8706,11 @@ cfg_fail_out:
 
 	/* Unconfigure MSI-X capability structure */
 	pci_disable_msix(phba->pcidev);
+	return rc;
 
-vec_fail_out:
+msg_fail_out:
+	lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
+			"0484 PCI enable MSI-X failed (%d)\n", rc);
 	return rc;
 }
 
-- 
1.7.7.6

[PATCH RFC 45/77] megaraid: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c |   20 +++++++++-----------
 1 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 3020921..b5973e4 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3727,18 +3727,16 @@ static int megasas_init_fw(struct megasas_instance *instance)
 					     (unsigned int)num_online_cpus());
 		for (i = 0; i < instance->msix_vectors; i++)
 			instance->msixentry[i].entry = i;
-		i = pci_enable_msix(instance->pdev, instance->msixentry,
-				    instance->msix_vectors);
-		if (i >= 0) {
-			if (i) {
-				if (!pci_enable_msix(instance->pdev,
-						     instance->msixentry, i))
-					instance->msix_vectors = i;
-				else
-					instance->msix_vectors = 0;
-			}
-		} else
+		i = pci_msix_table_size(instance->pdev);
+		if (i < 0) {
 			instance->msix_vectors = 0;
+		} else {
+			if (!pci_enable_msix(instance->pdev,
+					     instance->msixentry, i))
+				instance->msix_vectors = i;
+			else
+				instance->msix_vectors = 0;
+		}
 
 		dev_info(&instance->pdev->dev, "[scsi%d]: FW supports"
 			"<%d> MSIX vector,Online CPUs: <%d>,"
-- 
1.7.7.6

[PATCH RFC 46/77] mlx4: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx4/main.c |   17 ++++++++---------
 1 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 60c9f4f..377a5ea 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -1852,8 +1852,16 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)
 	int i;
 
 	if (msi_x) {
+		err = pci_msix_table_size(dev->pdev);
+		if (err < 0)
+			goto no_msi;
+
+		/* Try if at least 2 vectors are available */
 		nreq = min_t(int, dev->caps.num_eqs - dev->caps.reserved_eqs,
 			     nreq);
+		nreq = min_t(int, nreq, err);
+		if (nreq < 2)
+			goto no_msi;
 
 		entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
 		if (!entries)
@@ -1862,17 +1870,8 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)
 		for (i = 0; i < nreq; ++i)
 			entries[i].entry = i;
 
-	retry:
 		err = pci_enable_msix(dev->pdev, entries, nreq);
 		if (err) {
-			/* Try again if at least 2 vectors are available */
-			if (err > 1) {
-				mlx4_info(dev, "Requested %d vectors, "
-					  "but only %d MSI-X vectors available, "
-					  "trying again\n", nreq, err);
-				nreq = err;
-				goto retry;
-			}
 			kfree(entries);
 			goto no_msi;
 		}
-- 
1.7.7.6

Re: [PATCH RFC 46/77] mlx4: Update MSI/MSI-X interrupts enablement code

[Jack Morgenstein]

On Wed,  2 Oct 2013 12:49:02 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

NACK.  This change does not do anything logically as far as I can tell.
pci_enable_msix in the current upstream kernel itself calls
pci_msix_table_size.  The current code yields the same results
as the code suggested below. (i.e., the suggested code has no effect on
optimality).

BTW, pci_msix_table_size never returns a value < 0 (if msix is not
enabled, it returns 0 for the table size), so the (err < 0) check here
is not correct. (I also do not like using "err" here anyway for the
value returned by pci_msix_table_size().  There is no error here, and
it is simply confusing.

-Jack

> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/net/ethernet/mellanox/mlx4/main.c |   17 ++++++++---------
>  1 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c
> b/drivers/net/ethernet/mellanox/mlx4/main.c index 60c9f4f..377a5ea
> 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/main.c
> @@ -1852,8 +1852,16 @@ static void mlx4_enable_msi_x(struct mlx4_dev
> *dev) int i;
>  
>  	if (msi_x) {
> +		err = pci_msix_table_size(dev->pdev);
> +		if (err < 0)
> +			goto no_msi;
> +
> +		/* Try if at least 2 vectors are available */
>  		nreq = min_t(int, dev->caps.num_eqs -
> dev->caps.reserved_eqs, nreq);
> +		nreq = min_t(int, nreq, err);
> +		if (nreq < 2)
> +			goto no_msi;
>  
>  		entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
>  		if (!entries)
> @@ -1862,17 +1870,8 @@ static void mlx4_enable_msi_x(struct mlx4_dev
> *dev) for (i = 0; i < nreq; ++i)
>  			entries[i].entry = i;
>  
> -	retry:
>  		err = pci_enable_msix(dev->pdev, entries, nreq);
>  		if (err) {
> -			/* Try again if at least 2 vectors are
> available */
> -			if (err > 1) {
> -				mlx4_info(dev, "Requested %d
> vectors, "
> -					  "but only %d MSI-X vectors
> available, "
> -					  "trying again\n", nreq,
> err);
> -				nreq = err;
> -				goto retry;
> -			}
>  			kfree(entries);
>  			goto no_msi;
>  		}

Re: [PATCH RFC 46/77] mlx4: Update MSI/MSI-X interrupts enablement code

[Jack Morgenstein]

On Wed,  2 Oct 2013 12:49:02 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

UPDATING THIS REPLY.
Your change log confused me. The change below is not from a "recent
re-design", it is required due to an earlier patch in this patch set.
From the log, I assumed that the change you are talking about is already
upstream.

I will re-review.

-Jack

NACK.  This change does not do anything logically as far as I can tell.
pci_enable_msix in the current upstream kernel itself calls
pci_msix_table_size.  The current code yields the same resultswill
as the code suggested below. (i.e., the suggested code has no effect on
optimality).

BTW, pci_msix_table_size never returns a value < 0 (if msix is not
enabled, it returns 0 for the table size), so the (err < 0) check here
is not correct. (I also do not like using "err" here anyway for the
value returned by pci_msix_table_size().  There is no error here, and
it is simply confusing.

-Jack

> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/net/ethernet/mellanox/mlx4/main.c |   17 ++++++++---------
>  1 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c
> b/drivers/net/ethernet/mellanox/mlx4/main.c index 60c9f4f..377a5ea
> 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/main.c
> @@ -1852,8 +1852,16 @@ static void mlx4_enable_msi_x(struct mlx4_dev
> *dev) int i;
>  
>  	if (msi_x) {
> +		err = pci_msix_table_size(dev->pdev);
> +		if (err < 0)
> +			goto no_msi;
> +
> +		/* Try if at least 2 vectors are available */
>  		nreq = min_t(int, dev->caps.num_eqs -
> dev->caps.reserved_eqs, nreq);
> +		nreq = min_t(int, nreq, err);
> +		if (nreq < 2)
> +			goto no_msi;
>  
>  		entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
>  		if (!entries)
> @@ -1862,17 +1870,8 @@ static void mlx4_enable_msi_x(struct mlx4_dev
> *dev) for (i = 0; i < nreq; ++i)
>  			entries[i].entry = i;
>  
> -	retry:
>  		err = pci_enable_msix(dev->pdev, entries, nreq);
>  		if (err) {
> -			/* Try again if at least 2 vectors are
> available */
> -			if (err > 1) {
> -				mlx4_info(dev, "Requested %d
> vectors, "
> -					  "but only %d MSI-X vectors
> available, "
> -					  "trying again\n", nreq,
> err);
> -				nreq = err;
> -				goto retry;
> -			}
>  			kfree(entries);
>  			goto no_msi;
>  		}

Re: [PATCH RFC 46/77] mlx4: Update MSI/MSI-X interrupts enablement code

[Jack Morgenstein]

On Wed,  2 Oct 2013 12:49:02 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>

New review -- ACK (i.e., patch is OK), subject to acceptance of patches
05 and 07 of this patch set.

I sent my previous review (NACK) when I was not yet aware that
changes proposed were due to the two earlier patches (mentioned above)
in the current patch set.

The change log here should actually read something like the following:

As a result of changes to the MSI/MSI_X enabling procedures, this driver
must be modified in order to preserve its current msi/msi_x enablement
logic.

-Jack

[PATCH RFC 47/77] mlx5: Fix memory leak in case not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index b47739b..3573ba4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -142,6 +142,7 @@ retry:
 	}
 
 	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
+	kfree(table->msix_arr);
 
 	return 0;
 }
-- 
1.7.7.6

[PATCH RFC 48/77] mlx5: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 3573ba4..5e5c9a3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -122,7 +122,7 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
 	nvec = dev->caps.num_ports * num_online_cpus() + MLX5_EQ_VEC_COMP_BASE;
 	nvec = min_t(int, nvec, num_eqs);
 	if (nvec <= MLX5_EQ_VEC_COMP_BASE)
-		return -ENOMEM;
+		return -ENOSPC;
 
 	table->msix_arr = kzalloc(nvec * sizeof(*table->msix_arr), GFP_KERNEL);
 	if (!table->msix_arr)
@@ -144,7 +144,7 @@ retry:
 	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
 	kfree(table->msix_arr);
 
-	return 0;
+	return -ENOSPC;
 }
 
 static void mlx5_disable_msix(struct mlx5_core_dev *dev)
-- 
1.7.7.6

[PATCH RFC 49/77] mlx5: Fix minimum number of MSI-Xs

[Alexander Gordeev]

The minimum number of MSI-Xs is (MLX5_EQ_VEC_COMP_BASE + 1) in
one check and 2 in another check. Make the checks consistent and
assume the minimum number is (MLX5_EQ_VEC_COMP_BASE + 1).

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 5e5c9a3..adf0e5d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -136,7 +136,7 @@ retry:
 	err = pci_enable_msix(dev->pdev, table->msix_arr, nvec);
 	if (err <= 0) {
 		return err;
-	} else if (err > 2) {
+	} else if (err > MLX5_EQ_VEC_COMP_BASE) {
 		nvec = err;
 		goto retry;
 	}
-- 
1.7.7.6

[PATCH RFC 50/77] mlx5: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c |   18 +++++++++---------
 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index adf0e5d..5c21e50 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -119,8 +119,13 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
 	int err;
 	int i;
 
+	err = pci_msix_table_size(dev->pdev);
+	if (err < 0)
+		return err;
+
 	nvec = dev->caps.num_ports * num_online_cpus() + MLX5_EQ_VEC_COMP_BASE;
 	nvec = min_t(int, nvec, num_eqs);
+	nvec = min_t(int, nvec, err);
 	if (nvec <= MLX5_EQ_VEC_COMP_BASE)
 		return -ENOSPC;
 
@@ -131,20 +136,15 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
 	for (i = 0; i < nvec; i++)
 		table->msix_arr[i].entry = i;
 
-retry:
-	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
 	err = pci_enable_msix(dev->pdev, table->msix_arr, nvec);
-	if (err <= 0) {
+	if (err) {
+		kfree(table->msix_arr);
 		return err;
-	} else if (err > MLX5_EQ_VEC_COMP_BASE) {
-		nvec = err;
-		goto retry;
 	}
 
-	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
-	kfree(table->msix_arr);
+	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
 
-	return -ENOSPC;
+	return 0;
 }
 
 static void mlx5_disable_msix(struct mlx5_core_dev *dev)
-- 
1.7.7.6

Re: [PATCH RFC 50/77] mlx5: Update MSI/MSI-X interrupts enablement code

[Eli Cohen]

On Wed, Oct 02, 2013 at 12:49:06PM +0200, Alexander Gordeev wrote:
>  
> +	err = pci_msix_table_size(dev->pdev);
> +	if (err < 0)
> +		return err;
> +
>  	nvec = dev->caps.num_ports * num_online_cpus() + MLX5_EQ_VEC_COMP_BASE;
>  	nvec = min_t(int, nvec, num_eqs);
> +	nvec = min_t(int, nvec, err);
>  	if (nvec <= MLX5_EQ_VEC_COMP_BASE)
>  		return -ENOSPC;

Making sure we don't request more vectors then the device's is capable
of -- looks good.
>  
> @@ -131,20 +136,15 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
>  	for (i = 0; i < nvec; i++)
>  		table->msix_arr[i].entry = i;
>  
> -retry:
> -	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
>  	err = pci_enable_msix(dev->pdev, table->msix_arr, nvec);
> -	if (err <= 0) {
> +	if (err) {
> +		kfree(table->msix_arr);
>  		return err;
> -	} else if (err > MLX5_EQ_VEC_COMP_BASE) {
> -		nvec = err;
> -		goto retry;
>  	}
>  

According to latest sources, pci_enable_msix() may still fail so why
do you want to remove this code?

> -	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
> -	kfree(table->msix_arr);
> +	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
>  
> -	return -ENOSPC;
> +	return 0;
>  }
>  
>  static void mlx5_disable_msix(struct mlx5_core_dev *dev)
> -- 
> 1.7.7.6
> 
> --
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> the body of a message to majordomo@vger.kernel.org
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Re: [PATCH RFC 50/77] mlx5: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

On Thu, Oct 03, 2013 at 10:14:33AM +0300, Eli Cohen wrote:
> On Wed, Oct 02, 2013 at 12:49:06PM +0200, Alexander Gordeev wrote:
> >  
> > +	err = pci_msix_table_size(dev->pdev);
> > +	if (err < 0)
> > +		return err;
> > +
> >  	nvec = dev->caps.num_ports * num_online_cpus() + MLX5_EQ_VEC_COMP_BASE;
> >  	nvec = min_t(int, nvec, num_eqs);
> > +	nvec = min_t(int, nvec, err);
> >  	if (nvec <= MLX5_EQ_VEC_COMP_BASE)
> >  		return -ENOSPC;
> 
> Making sure we don't request more vectors then the device's is capable
> of -- looks good.
> >  
> > @@ -131,20 +136,15 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
> >  	for (i = 0; i < nvec; i++)
> >  		table->msix_arr[i].entry = i;
> >  
> > -retry:
> > -	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
> >  	err = pci_enable_msix(dev->pdev, table->msix_arr, nvec);
> > -	if (err <= 0) {
> > +	if (err) {
> > +		kfree(table->msix_arr);
> >  		return err;
> > -	} else if (err > MLX5_EQ_VEC_COMP_BASE) {
> > -		nvec = err;
> > -		goto retry;
> >  	}
> >  
> 
> According to latest sources, pci_enable_msix() may still fail so why
> do you want to remove this code?

pci_enable_msix() may fail, but it can not return a positive number.

We first calculate how many MSI-Xs we need, adjust to what we can get,
check if that is enough and only then go for it.

> > -	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
> > -	kfree(table->msix_arr);
> > +	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
> >  
> > -	return -ENOSPC;
> > +	return 0;
> >  }
> >  
> >  static void mlx5_disable_msix(struct mlx5_core_dev *dev)

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

[PATCH RFC 51/77] mthca: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/infiniband/hw/mthca/mthca_main.c |   16 +++++++++++-----
 1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_main.c b/drivers/infiniband/hw/mthca/mthca_main.c
index 87897b9..3d44ca4 100644
--- a/drivers/infiniband/hw/mthca/mthca_main.c
+++ b/drivers/infiniband/hw/mthca/mthca_main.c
@@ -854,17 +854,23 @@ static int mthca_enable_msi_x(struct mthca_dev *mdev)
 	struct msix_entry entries[3];
 	int err;
 
+	err = pci_msix_table_size(mdev->pdev);
+	if (err < 0)
+		return err;
+	if (err < ARRAY_SIZE(entries)) {
+		mthca_info(mdev, "Only %d MSI-X vectors available, "
+			   "not using MSI-X\n", err);
+
+		return -ENOSPC;
+	}
+
 	entries[0].entry = 0;
 	entries[1].entry = 1;
 	entries[2].entry = 2;
 
 	err = pci_enable_msix(mdev->pdev, entries, ARRAY_SIZE(entries));
-	if (err) {
-		if (err > 0)
-			mthca_info(mdev, "Only %d MSI-X vectors available, "
-				   "not using MSI-X\n", err);
+	if (err)
 		return err;
-	}
 
 	mdev->eq_table.eq[MTHCA_EQ_COMP ].msi_x_vector = entries[0].vector;
 	mdev->eq_table.eq[MTHCA_EQ_ASYNC].msi_x_vector = entries[1].vector;
-- 
1.7.7.6

Re: [PATCH RFC 51/77] mthca: Update MSI/MSI-X interrupts enablement code

[Jack Morgenstein]

On Wed,  2 Oct 2013 12:49:07 +0200
Alexander Gordeev <agordeev@redhat.com> wrote:

> Subject: [PATCH RFC 51/77] mthca: Update MSI/MSI-X interrupts
> enablement code Date: Wed,  2 Oct 2013 12:49:07 +0200
> Sender: linux-rdma-owner@vger.kernel.org
> X-Mailer: git-send-email 1.7.7.6
> 
> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---

ACK.

-Jack

[PATCH RFC 52/77] niu: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/sun/niu.c |   20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index f28460c..54c41b9 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -9051,26 +9051,28 @@ static void niu_try_msix(struct niu *np, u8 *ldg_num_map)
 		    (np->port == 0 ? 3 : 1));
 	BUG_ON(num_irqs > (NIU_NUM_LDG / parent->num_ports));
 
-retry:
+	err = pci_msix_table_size(pdev);
+	if (err < 0)
+		goto fail;
+
+	num_irqs = min(num_irqs, err);
 	for (i = 0; i < num_irqs; i++) {
 		msi_vec[i].vector = 0;
 		msi_vec[i].entry = i;
 	}
 
 	err = pci_enable_msix(pdev, msi_vec, num_irqs);
-	if (err < 0) {
-		np->flags &= ~NIU_FLAGS_MSIX;
-		return;
-	}
-	if (err > 0) {
-		num_irqs = err;
-		goto retry;
-	}
+	if (err)
+		goto fail;
 
 	np->flags |= NIU_FLAGS_MSIX;
 	for (i = 0; i < num_irqs; i++)
 		np->ldg[i].irq = msi_vec[i].vector;
 	np->num_ldg = num_irqs;
+	return;
+
+fail:
+	np->flags &= ~NIU_FLAGS_MSIX;
 }
 
 static int niu_n2_irq_init(struct niu *np, u8 *ldg_num_map)
-- 
1.7.7.6

[PATCH RFC 53/77] ntb: Fix missed call to pci_enable_msix()

[Alexander Gordeev]

Current MSI-X enablement code assumes MSI-Xs were successfully
allocated in case less than requested vectors were available.
That assumption is wrong, since MSI-Xs should be enabled with
a repeated call to pci_enable_msix(). This update fixes this.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/ntb/ntb_hw.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index 1cb6e51..de2062c 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1075,6 +1075,10 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 			 "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
 			 rc);
 		msix_entries = rc;
+
+		rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
+		if (rc)
+			goto err1;
 	}
 
 	for (i = 0; i < msix_entries; i++) {
-- 
1.7.7.6

Re: [PATCH RFC 53/77] ntb: Fix missed call to pci_enable_msix()

[Jon Mason]

On Wed, Oct 02, 2013 at 12:49:09PM +0200, Alexander Gordeev wrote:
> Current MSI-X enablement code assumes MSI-Xs were successfully
> allocated in case less than requested vectors were available.
> That assumption is wrong, since MSI-Xs should be enabled with
> a repeated call to pci_enable_msix(). This update fixes this.

Good catch, I'll pull it in for my next NTB release.

Thanks,
Jon

> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/ntb/ntb_hw.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index 1cb6e51..de2062c 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -1075,6 +1075,10 @@ static int ntb_setup_msix(struct ntb_device *ndev)
>  			 "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
>  			 rc);
>  		msix_entries = rc;
> +
> +		rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> +		if (rc)
> +			goto err1;
>  	}
>  
>  	for (i = 0; i < msix_entries; i++) {
> -- 
> 1.7.7.6
> 

[PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/ntb/ntb_hw.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index de2062c..eccd5e5 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 		/* On SNB, the link interrupt is always tied to 4th vector.  If
 		 * we can't get all 4, then we can't use MSI-X.
 		 */
-		if (ndev->hw_type != BWD_HW) {
+		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
 			rc = -EIO;
 			goto err1;
 		}
-- 
1.7.7.6

Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Jon Mason]

On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/ntb/ntb_hw.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index de2062c..eccd5e5 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
>  		/* On SNB, the link interrupt is always tied to 4th vector.  If
>  		 * we can't get all 4, then we can't use MSI-X.
>  		 */
> -		if (ndev->hw_type != BWD_HW) {
> +		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {

Nack, this check is unnecessary.

Also, no comment in the commit on why it could be necessary.


>  			rc = -EIO;
>  			goto err1;
>  		}
> -- 
> 1.7.7.6
> 

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Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Alexander Gordeev]

On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
> On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > ---
> >  drivers/ntb/ntb_hw.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> > index de2062c..eccd5e5 100644
> > --- a/drivers/ntb/ntb_hw.c
> > +++ b/drivers/ntb/ntb_hw.c
> > @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> >  		/* On SNB, the link interrupt is always tied to 4th vector.  If
> >  		 * we can't get all 4, then we can't use MSI-X.
> >  		 */
> > -		if (ndev->hw_type != BWD_HW) {
> > +		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
> 
> Nack, this check is unnecessary.

If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
to enable less than maximum MSI-Xs in case the maximum was not allocated.
Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Jon Mason]

On Sat, Oct 05, 2013 at 11:43:04PM +0200, Alexander Gordeev wrote:
> On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
> > On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> > > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > > ---
> > >  drivers/ntb/ntb_hw.c |    2 +-
> > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> > > index de2062c..eccd5e5 100644
> > > --- a/drivers/ntb/ntb_hw.c
> > > +++ b/drivers/ntb/ntb_hw.c
> > > @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> > >  		/* On SNB, the link interrupt is always tied to 4th vector.  If
> > >  		 * we can't get all 4, then we can't use MSI-X.
> > >  		 */
> > > -		if (ndev->hw_type != BWD_HW) {
> > > +		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
> > 
> > Nack, this check is unnecessary.
> 
> If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
> to enable less than maximum MSI-Xs in case the maximum was not allocated.
> Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.

Per the comment in the code snippet above, "If we can't get all 4,
then we can't use MSI-X".  There is already a check to see if more
than 4 were acquired.  So it's not possible to hit this.  Even if it
was, don't use SNB_MSIX_CNT here (limits.msix_cnt is the preferred
variable).  Also, the "()" are unnecessary.

Thanks,
Jon

> -- 
> Regards,
> Alexander Gordeev
> agordeev@redhat.com

Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 09:50:57AM -0700, Jon Mason wrote:
> On Sat, Oct 05, 2013 at 11:43:04PM +0200, Alexander Gordeev wrote:
> > On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
> > > On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> > > > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > > > ---
> > > >  drivers/ntb/ntb_hw.c |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > 
> > > > diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> > > > index de2062c..eccd5e5 100644
> > > > --- a/drivers/ntb/ntb_hw.c
> > > > +++ b/drivers/ntb/ntb_hw.c
> > > > @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> > > >  		/* On SNB, the link interrupt is always tied to 4th vector.  If
> > > >  		 * we can't get all 4, then we can't use MSI-X.
> > > >  		 */
> > > > -		if (ndev->hw_type != BWD_HW) {
> > > > +		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
> > > 
> > > Nack, this check is unnecessary.
> > 
> > If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
> > to enable less than maximum MSI-Xs in case the maximum was not allocated.
> > Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.
> 
> Per the comment in the code snippet above, "If we can't get all 4,
> then we can't use MSI-X".  There is already a check to see if more
> than 4 were acquired.  So it's not possible to hit this.  Even if it
> was, don't use SNB_MSIX_CNT here (limits.msix_cnt is the preferred
> variable).  Also, the "()" are unnecessary.

The changelog is definitely bogus. I meant here an improvement to the
existing scheme, not a conversion to the new one:

	msix_entries = msix_table_size(val);

Getting i.e. 16 vectors here.

	if (msix_entries > ndev->limits.msix_cnt) {
		rc = -EINVAL;
		goto err;
	}

Upper limit check i.e. succeeds.

	[...]

	rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);

pci_enable_msix() does not success and returns i.e. 8 here, should retry.

	if (rc < 0)
		goto err1;
	if (rc > 0) {
		/* On SNB, the link interrupt is always tied to 4th vector.  If
		 * we can't get all 4, then we can't use MSI-X.
		 */
		if (ndev->hw_type != BWD_HW) {

On SNB bail out here, although could have continue with 8 vectors.
Can only use SNB_MSIX_CNT here, since limits.msix_cnt is the upper limit.

			rc = -EIO;
			goto err1;
		}

		[...]
	}

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

[Jon Mason]

On Mon, Oct 07, 2013 at 08:38:45PM +0200, Alexander Gordeev wrote:
> On Mon, Oct 07, 2013 at 09:50:57AM -0700, Jon Mason wrote:
> > On Sat, Oct 05, 2013 at 11:43:04PM +0200, Alexander Gordeev wrote:
> > > On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
> > > > On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> > > > > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > > > > ---
> > > > >  drivers/ntb/ntb_hw.c |    2 +-
> > > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> > > > > index de2062c..eccd5e5 100644
> > > > > --- a/drivers/ntb/ntb_hw.c
> > > > > +++ b/drivers/ntb/ntb_hw.c
> > > > > @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> > > > >  		/* On SNB, the link interrupt is always tied to 4th vector.  If
> > > > >  		 * we can't get all 4, then we can't use MSI-X.
> > > > >  		 */
> > > > > -		if (ndev->hw_type != BWD_HW) {
> > > > > +		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
> > > > 
> > > > Nack, this check is unnecessary.
> > > 
> > > If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
> > > to enable less than maximum MSI-Xs in case the maximum was not allocated.
> > > Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.
> > 
> > Per the comment in the code snippet above, "If we can't get all 4,
> > then we can't use MSI-X".  There is already a check to see if more
> > than 4 were acquired.  So it's not possible to hit this.  Even if it
> > was, don't use SNB_MSIX_CNT here (limits.msix_cnt is the preferred
> > variable).  Also, the "()" are unnecessary.
> 
> The changelog is definitely bogus. I meant here an improvement to the
> existing scheme, not a conversion to the new one:
> 
> 	msix_entries = msix_table_size(val);
> 
> Getting i.e. 16 vectors here.
> 
> 	if (msix_entries > ndev->limits.msix_cnt) {

On SNB HW, limits.msix_cnt is set to SNB_MSIX_CNT (4)
http://lxr.free-electrons.com/source/drivers/ntb/ntb_hw.c#L558

> 		rc = -EINVAL;
> 		goto err;
> 	}
> 
> Upper limit check i.e. succeeds.
> 
> 	[...]
> 
> 	rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> 
> pci_enable_msix() does not success and returns i.e. 8 here, should retry.

Per the above, since our upper bound is 4.  We will either have this
return 0 for all 4 or a number between 1 and 3 (or an error, but
that's not relevant to this discussion).

> 	if (rc < 0)
> 		goto err1;
> 	if (rc > 0) {
> 		/* On SNB, the link interrupt is always tied to 4th vector.  If
> 		 * we can't get all 4, then we can't use MSI-X.
> 		 */
> 		if (ndev->hw_type != BWD_HW) {
> 
> On SNB bail out here, although could have continue with 8 vectors.
> Can only use SNB_MSIX_CNT here, since limits.msix_cnt is the upper limit.

Since we can guarantee that rc is between 1 and 3 at this point (on
SNB HW), we should error out.

Thanks,
Jon


> 
> 			rc = -EIO;
> 			goto err1;
> 		}
> 
> 		[...]
> 	}
> 
> -- 
> Regards,
> Alexander Gordeev
> agordeev@redhat.com

[PATCH RFC 55/77] ntb: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/ntb/ntb_hw.c |   41 +++++++++++++----------------------------
 drivers/ntb/ntb_hw.h |    2 --
 2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index eccd5e5..7776429 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1032,23 +1032,26 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 	struct msix_entry *msix;
 	int msix_entries;
 	int rc, i;
-	u16 val;
 
-	if (!pdev->msix_cap) {
-		rc = -EIO;
+	rc = pci_msix_table_size(pdev);
+	if (rc < 0)
 		goto err;
-	}
 
-	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
-	if (rc)
+	/*
+	 * On SNB, the link interrupt is always tied to 4th vector.  If
+	 * we can't get all 4, then we can't use MSI-X.
+	 */
+	if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
+		rc = -ENOSPC;
 		goto err;
-
-	msix_entries = msix_table_size(val);
-	if (msix_entries > ndev->limits.msix_cnt) {
+	}
+	if (rc > ndev->limits.msix_cnt) {
 		rc = -EINVAL;
 		goto err;
 	}
 
+	msix_entries = rc;
+
 	ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
 				     GFP_KERNEL);
 	if (!ndev->msix_entries) {
@@ -1060,26 +1063,8 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 		ndev->msix_entries[i].entry = i;
 
 	rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
-	if (rc < 0)
+	if (rc)
 		goto err1;
-	if (rc > 0) {
-		/* On SNB, the link interrupt is always tied to 4th vector.  If
-		 * we can't get all 4, then we can't use MSI-X.
-		 */
-		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
-			rc = -EIO;
-			goto err1;
-		}
-
-		dev_warn(&pdev->dev,
-			 "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
-			 rc);
-		msix_entries = rc;
-
-		rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
-		if (rc)
-			goto err1;
-	}
 
 	for (i = 0; i < msix_entries; i++) {
 		msix = &ndev->msix_entries[i];
diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
index 0a31ced..50bd760 100644
--- a/drivers/ntb/ntb_hw.h
+++ b/drivers/ntb/ntb_hw.h
@@ -60,8 +60,6 @@
 #define PCI_DEVICE_ID_INTEL_NTB_SS_HSX		0x2F0F
 #define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD		0x0C4E
 
-#define msix_table_size(control)	((control & PCI_MSIX_FLAGS_QSIZE)+1)
-
 #ifndef readq
 static inline u64 readq(void __iomem *addr)
 {
-- 
1.7.7.6

Re: [PATCH RFC 55/77] ntb: Update MSI/MSI-X interrupts enablement code

[Jon Mason]

On Wed, Oct 02, 2013 at 12:49:11PM +0200, Alexander Gordeev wrote:
> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/ntb/ntb_hw.c |   41 +++++++++++++----------------------------
>  drivers/ntb/ntb_hw.h |    2 --
>  2 files changed, 13 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index eccd5e5..7776429 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -1032,23 +1032,26 @@ static int ntb_setup_msix(struct ntb_device *ndev)
>  	struct msix_entry *msix;
>  	int msix_entries;
>  	int rc, i;
> -	u16 val;
>  
> -	if (!pdev->msix_cap) {
> -		rc = -EIO;
> +	rc = pci_msix_table_size(pdev);
> +	if (rc < 0)
>  		goto err;
> -	}
>  
> -	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
> -	if (rc)
> +	/*
> +	 * On SNB, the link interrupt is always tied to 4th vector.  If
> +	 * we can't get all 4, then we can't use MSI-X.
> +	 */
> +	if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {

Please check for the HW type first, and then compare to
ndev->limits.msix_cnt (which will be SNB_MSIX_CNT on SNB HW).  Also,
put the comment inside the if statement and remove the unecessary "()"
around the comparisons.  OCD on my part, but I like it that way.  

> +		rc = -ENOSPC;
>  		goto err;
> -
> -	msix_entries = msix_table_size(val);
> -	if (msix_entries > ndev->limits.msix_cnt) {
> +	}

else if...

> +	if (rc > ndev->limits.msix_cnt) {
>  		rc = -EINVAL;
>  		goto err;
>  	}
>  
> +	msix_entries = rc;
> +
>  	ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
>  				     GFP_KERNEL);
>  	if (!ndev->msix_entries) {
> @@ -1060,26 +1063,8 @@ static int ntb_setup_msix(struct ntb_device *ndev)
>  		ndev->msix_entries[i].entry = i;
>  
>  	rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> -	if (rc < 0)
> +	if (rc)
>  		goto err1;
> -	if (rc > 0) {
> -		/* On SNB, the link interrupt is always tied to 4th vector.  If
> -		 * we can't get all 4, then we can't use MSI-X.
> -		 */
> -		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
> -			rc = -EIO;
> -			goto err1;
> -		}
> -
> -		dev_warn(&pdev->dev,
> -			 "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
> -			 rc);
> -		msix_entries = rc;
> -
> -		rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> -		if (rc)
> -			goto err1;
> -	}
>  
>  	for (i = 0; i < msix_entries; i++) {
>  		msix = &ndev->msix_entries[i];
> diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
> index 0a31ced..50bd760 100644
> --- a/drivers/ntb/ntb_hw.h
> +++ b/drivers/ntb/ntb_hw.h
> @@ -60,8 +60,6 @@
>  #define PCI_DEVICE_ID_INTEL_NTB_SS_HSX		0x2F0F
>  #define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD		0x0C4E
>  
> -#define msix_table_size(control)	((control & PCI_MSIX_FLAGS_QSIZE)+1)

Good riddance!  :-)

> -
>  #ifndef readq
>  static inline u64 readq(void __iomem *addr)
>  {
> -- 
> 1.7.7.6
> 

[PATCH RFC 56/77] nvme: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/block/nvme-core.c |   48 +++++++++++++++++++++++---------------------
 1 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index da52092..f69d7af 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1774,34 +1774,36 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	/* Deregister the admin queue's interrupt */
 	free_irq(dev->entry[0].vector, dev->queues[0]);
 
-	vecs = nr_io_queues;
+	result = pci_msix_table_size(pdev);
+	if (result < 0)
+		goto msi;
+
+	vecs = min(result, nr_io_queues);
 	for (i = 0; i < vecs; i++)
 		dev->entry[i].entry = i;
-	for (;;) {
-		result = pci_enable_msix(pdev, dev->entry, vecs);
-		if (result <= 0)
-			break;
-		vecs = result;
-	}
 
-	if (result < 0) {
-		vecs = nr_io_queues;
-		if (vecs > 32)
-			vecs = 32;
-		for (;;) {
-			result = pci_enable_msi_block(pdev, vecs);
-			if (result == 0) {
-				for (i = 0; i < vecs; i++)
-					dev->entry[i].vector = i + pdev->irq;
-				break;
-			} else if (result < 0) {
-				vecs = 1;
-				break;
-			}
-			vecs = result;
-		}
+	result = pci_enable_msix(pdev, dev->entry, vecs);
+	if (result == 0)
+		goto irq;
+
+ msi:
+	result = pci_get_msi_cap(pdev);
+	if (result < 0)
+		goto no_msi;
+
+	vecs = min(result, nr_io_queues);
+
+	result = pci_enable_msi_block(pdev, vecs);
+	if (result == 0) {
+		for (i = 0; i < vecs; i++)
+			dev->entry[i].vector = i + pdev->irq;
+		goto irq;
 	}
 
+ no_msi:
+	vecs = 1;
+
+ irq:
 	/*
 	 * Should investigate if there's a performance win from allocating
 	 * more queues than interrupt vectors; it might allow the submission
-- 
1.7.7.6

[PATCH RFC 57/77] pmcraid: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/pmcraid.c |   23 +++++++++++------------
 1 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 1eb7b028..5c62d22 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -4680,24 +4680,23 @@ pmcraid_register_interrupt_handler(struct pmcraid_instance *pinstance)
 
 	if ((pmcraid_enable_msix) &&
 		(pci_find_capability(pdev, PCI_CAP_ID_MSIX))) {
-		int num_hrrq = PMCRAID_NUM_MSIX_VECTORS;
 		struct msix_entry entries[PMCRAID_NUM_MSIX_VECTORS];
+		int num_hrrq = ARRAY_SIZE(entries);
 		int i;
-		for (i = 0; i < PMCRAID_NUM_MSIX_VECTORS; i++)
-			entries[i].entry = i;
-
-		rc = pci_enable_msix(pdev, entries, num_hrrq);
-		if (rc < 0)
-			goto pmcraid_isr_legacy;
 
 		/* Check how many MSIX vectors are allocated and register
 		 * msi-x handlers for each of them giving appropriate buffer
 		 */
-		if (rc > 0) {
-			num_hrrq = rc;
-			if (pci_enable_msix(pdev, entries, num_hrrq))
-				goto pmcraid_isr_legacy;
-		}
+		rc = pci_msix_table_size(pdev);
+		if (rc < 0)
+			goto pmcraid_isr_legacy;
+
+		num_hrrq = min(num_hrrq, rc);
+		for (i = 0; i < num_hrrq; i++)
+			entries[i].entry = i;
+
+		if (pci_enable_msix(pdev, entries, num_hrrq))
+			goto pmcraid_isr_legacy;
 
 		for (i = 0; i < num_hrrq; i++) {
 			pinstance->hrrq_vector[i].hrrq_id = i;
-- 
1.7.7.6

[PATCH RFC 58/77] qib: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/infiniband/hw/qib/qib_pcie.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/qib/qib_pcie.c b/drivers/infiniband/hw/qib/qib_pcie.c
index 3f14009..9580903 100644
--- a/drivers/infiniband/hw/qib/qib_pcie.c
+++ b/drivers/infiniband/hw/qib/qib_pcie.c
@@ -218,10 +218,6 @@ static void qib_msix_setup(struct qib_devdata *dd, int pos, u32 *msixcnt,
 	if (tabsize > *msixcnt)
 		tabsize = *msixcnt;
 	ret = pci_enable_msix(dd->pcidev, msix_entry, tabsize);
-	if (ret > 0) {
-		tabsize = ret;
-		ret = pci_enable_msix(dd->pcidev, msix_entry, tabsize);
-	}
 do_intx:
 	if (ret) {
 		qib_dev_err(dd,
-- 
1.7.7.6

[PATCH RFC 59/77] qla2xxx: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/scsi/qla2xxx/qla_isr.c |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index df1b30b..6c11ab9 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -2836,16 +2836,20 @@ qla24xx_enable_msix(struct qla_hw_data *ha, struct rsp_que *rsp)
 	for (i = 0; i < ha->msix_count; i++)
 		entries[i].entry = i;
 
-	ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
-	if (ret) {
+	ret = pci_msix_table_size(ha->pdev);
+	if (ret < 0) {
+		goto msix_failed;
+	} else {
 		if (ret < MIN_MSIX_COUNT)
 			goto msix_failed;
 
-		ql_log(ql_log_warn, vha, 0x00c6,
-		    "MSI-X: Failed to enable support "
-		    "-- %d/%d\n Retry with %d vectors.\n",
-		    ha->msix_count, ret, ret);
-		ha->msix_count = ret;
+		if (ret < ha->msix_count) {
+			ql_log(ql_log_warn, vha, 0x00c6,
+			    "MSI-X: Failed to enable support "
+			    "-- %d/%d\n Retry with %d vectors.\n",
+			    ha->msix_count, ret, ret);
+			ha->msix_count = ret;
+		}
 		ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
 		if (ret) {
 msix_failed:
-- 
1.7.7.6

Re: [PATCH RFC 59/77] qla2xxx: Update MSI/MSI-X interrupts enablement code

[Saurav Kashyap]

Acked-by: Saurav Kashyap <saurav.kashyap@qlogic.com>


>As result of recent re-design of the MSI/MSI-X interrupts enabling
>pattern this driver has to be updated to use the new technique to
>obtain a optimal number of MSI/MSI-X interrupts required.
>
>Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
>---
> drivers/scsi/qla2xxx/qla_isr.c |   18 +++++++++++-------
> 1 files changed, 11 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/scsi/qla2xxx/qla_isr.c
>b/drivers/scsi/qla2xxx/qla_isr.c
>index df1b30b..6c11ab9 100644
>--- a/drivers/scsi/qla2xxx/qla_isr.c
>+++ b/drivers/scsi/qla2xxx/qla_isr.c
>@@ -2836,16 +2836,20 @@ qla24xx_enable_msix(struct qla_hw_data *ha,
>struct rsp_que *rsp)
> 	for (i = 0; i < ha->msix_count; i++)
> 		entries[i].entry = i;
> 
>-	ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
>-	if (ret) {
>+	ret = pci_msix_table_size(ha->pdev);
>+	if (ret < 0) {
>+		goto msix_failed;
>+	} else {
> 		if (ret < MIN_MSIX_COUNT)
> 			goto msix_failed;
> 
>-		ql_log(ql_log_warn, vha, 0x00c6,
>-		    "MSI-X: Failed to enable support "
>-		    "-- %d/%d\n Retry with %d vectors.\n",
>-		    ha->msix_count, ret, ret);
>-		ha->msix_count = ret;
>+		if (ret < ha->msix_count) {
>+			ql_log(ql_log_warn, vha, 0x00c6,
>+			    "MSI-X: Failed to enable support "
>+			    "-- %d/%d\n Retry with %d vectors.\n",
>+			    ha->msix_count, ret, ret);
>+			ha->msix_count = ret;
>+		}
> 		ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
> 		if (ret) {
> msix_failed:
>-- 
>1.7.7.6
>
>--
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>More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH RFC 60/77] qlcnic: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index c4c5023..c6018bb 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -620,7 +620,7 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 				 num_msix);
 			if (qlcnic_83xx_check(adapter)) {
 				if (err < (QLC_83XX_MINIMUM_VECTOR - tx_vector))
-					return err;
+					return -ENOSPC;
 				err -= (max_tx_rings + 1);
 				num_msix = rounddown_pow_of_two(err);
 				num_msix += (max_tx_rings + 1);
@@ -636,6 +636,7 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 					 num_msix);
 				goto enable_msix;
 			}
+			err = -ENOSPC;
 		} else {
 			dev_info(&pdev->dev,
 				 "Unable to allocate %d MSI-X interrupt vectors\n",
-- 
1.7.7.6

[PATCH RFC 61/77] qlogic: Return -EINVAL in case MSI-X is not supported

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index c6018bb..ff6a78b 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -568,7 +568,7 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 {
 	struct pci_dev *pdev = adapter->pdev;
 	int max_tx_rings, max_sds_rings, tx_vector;
-	int err = -1, i;
+	int err = -EINVAL, i;
 
 	if (adapter->flags & QLCNIC_TX_INTR_SHARED) {
 		max_tx_rings = 0;
-- 
1.7.7.6

[PATCH RFC 62/77] qlcnic: Remove redundant return operator

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index ff6a78b..b94e679 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -613,7 +613,6 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 				adapter->max_sds_rings = max_sds_rings;
 			}
 			dev_info(&pdev->dev, "using msi-x interrupts\n");
-			return err;
 		} else if (err > 0) {
 			dev_info(&pdev->dev,
 				 "Unable to allocate %d MSI-X interrupt vectors\n",
-- 
1.7.7.6

[PATCH RFC 63/77] qlcnic: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |   56 ++++++++++++---------
 1 files changed, 32 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index b94e679..a137c14 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -590,7 +590,37 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 	adapter->flags &= ~(QLCNIC_MSI_ENABLED | QLCNIC_MSIX_ENABLED);
 
 	if (adapter->ahw->msix_supported) {
- enable_msix:
+		err = pci_msix_table_size(pdev);
+		if (err < 0)
+			goto fail;
+
+		if (err < num_msix) {
+			dev_info(&pdev->dev,
+				 "Unable to allocate %d MSI-X interrupt vectors\n",
+				 num_msix);
+			if (qlcnic_83xx_check(adapter)) {
+				if (err < (QLC_83XX_MINIMUM_VECTOR - tx_vector))
+					return -ENOSPC;
+				err -= (max_tx_rings + 1);
+				num_msix = rounddown_pow_of_two(err);
+				num_msix += (max_tx_rings + 1);
+			} else {
+				num_msix = rounddown_pow_of_two(err);
+				if (qlcnic_check_multi_tx(adapter))
+					num_msix += max_tx_rings;
+			}
+
+			if (!num_msix) {
+				err = -ENOSPC;
+				goto fail;
+			}
+
+			dev_info(&pdev->dev,
+				 "Trying to allocate %d MSI-X interrupt vectors\n",
+				 num_msix);
+			}
+		}
+
 		for (i = 0; i < num_msix; i++)
 			adapter->msix_entries[i].entry = i;
 		err = pci_enable_msix(pdev, adapter->msix_entries, num_msix);
@@ -613,30 +643,8 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 				adapter->max_sds_rings = max_sds_rings;
 			}
 			dev_info(&pdev->dev, "using msi-x interrupts\n");
-		} else if (err > 0) {
-			dev_info(&pdev->dev,
-				 "Unable to allocate %d MSI-X interrupt vectors\n",
-				 num_msix);
-			if (qlcnic_83xx_check(adapter)) {
-				if (err < (QLC_83XX_MINIMUM_VECTOR - tx_vector))
-					return -ENOSPC;
-				err -= (max_tx_rings + 1);
-				num_msix = rounddown_pow_of_two(err);
-				num_msix += (max_tx_rings + 1);
-			} else {
-				num_msix = rounddown_pow_of_two(err);
-				if (qlcnic_check_multi_tx(adapter))
-					num_msix += max_tx_rings;
-			}
-
-			if (num_msix) {
-				dev_info(&pdev->dev,
-					 "Trying to allocate %d MSI-X interrupt vectors\n",
-					 num_msix);
-				goto enable_msix;
-			}
-			err = -ENOSPC;
 		} else {
+fail:
 			dev_info(&pdev->dev,
 				 "Unable to allocate %d MSI-X interrupt vectors\n",
 				 num_msix);
-- 
1.7.7.6

RE: [PATCH RFC 63/77] qlcnic: Update MSI/MSI-X interrupts enablement code

[Himanshu Madhani]

> -----Original Message-----
> From: Alexander Gordeev [mailto:agordeev@redhat.com]
> Sent: Wednesday, October 02, 2013 3:49 AM
> To: linux-kernel
> Cc: Alexander Gordeev; Bjorn Helgaas; Ralf Baechle; Michael Ellerman;
> Benjamin Herrenschmidt; Martin Schwidefsky; Ingo Molnar; Tejun Heo; Dan
> Williams; Andy King; Jon Mason; Matt Porter; linux-pci; linux-mips@linux-
> mips.org; linuxppc-dev@lists.ozlabs.org; linux390@de.ibm.com; linux-
> s390@vger.kernel.org; x86@kernel.org; linux-ide@vger.kernel.org;
> iss_storagedev@hp.com; linux-nvme@lists.infradead.org; linux-
> rdma@vger.kernel.org; netdev; e1000-devel@lists.sourceforge.net; Dept-
> Eng Linux Driver; Solarflare linux maintainers; VMware, Inc.; linux-scsi
> Subject: [PATCH RFC 63/77] qlcnic: Update MSI/MSI-X interrupts enablement
> code
> 
> As result of recent re-design of the MSI/MSI-X interrupts enabling pattern
> this driver has to be updated to use the new technique to obtain a optimal
> number of MSI/MSI-X interrupts required.
> 
 "We will test this change for the driver and provide feedback."

> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>

Thanks,
Himanshu

[PATCH RFC 64/77] qlcnic: Make MSI-X initialization routine bit more readable

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |  112 +++++++++++-----------
 1 files changed, 56 insertions(+), 56 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index a137c14..8510457 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -568,7 +568,7 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 {
 	struct pci_dev *pdev = adapter->pdev;
 	int max_tx_rings, max_sds_rings, tx_vector;
-	int err = -EINVAL, i;
+	int err, i;
 
 	if (adapter->flags & QLCNIC_TX_INTR_SHARED) {
 		max_tx_rings = 0;
@@ -589,68 +589,68 @@ int qlcnic_enable_msix(struct qlcnic_adapter *adapter, u32 num_msix)
 	adapter->max_sds_rings = 1;
 	adapter->flags &= ~(QLCNIC_MSI_ENABLED | QLCNIC_MSIX_ENABLED);
 
-	if (adapter->ahw->msix_supported) {
-		err = pci_msix_table_size(pdev);
-		if (err < 0)
+	if (!adapter->ahw->msix_supported)
+		return -EINVAL;
+
+	err = pci_msix_table_size(pdev);
+	if (err < 0)
+		goto fail;
+
+	if (err < num_msix) {
+		dev_info(&pdev->dev,
+			 "Unable to allocate %d MSI-X interrupt vectors\n",
+			 num_msix);
+		if (qlcnic_83xx_check(adapter)) {
+			if (err < (QLC_83XX_MINIMUM_VECTOR - tx_vector))
+				return -ENOSPC;
+			err -= (max_tx_rings + 1);
+			num_msix = rounddown_pow_of_two(err);
+			num_msix += (max_tx_rings + 1);
+		} else {
+			num_msix = rounddown_pow_of_two(err);
+			if (qlcnic_check_multi_tx(adapter))
+				num_msix += max_tx_rings;
+		}
+
+		if (!num_msix) {
+			err = -ENOSPC;
 			goto fail;
+		}
 
-		if (err < num_msix) {
-			dev_info(&pdev->dev,
-				 "Unable to allocate %d MSI-X interrupt vectors\n",
-				 num_msix);
-			if (qlcnic_83xx_check(adapter)) {
-				if (err < (QLC_83XX_MINIMUM_VECTOR - tx_vector))
-					return -ENOSPC;
-				err -= (max_tx_rings + 1);
-				num_msix = rounddown_pow_of_two(err);
-				num_msix += (max_tx_rings + 1);
-			} else {
-				num_msix = rounddown_pow_of_two(err);
-				if (qlcnic_check_multi_tx(adapter))
-					num_msix += max_tx_rings;
-			}
+		dev_info(&pdev->dev,
+			 "Trying to allocate %d MSI-X interrupt vectors\n",
+			 num_msix);
+	}
 
-			if (!num_msix) {
-				err = -ENOSPC;
-				goto fail;
-			}
+	for (i = 0; i < num_msix; i++)
+		adapter->msix_entries[i].entry = i;
 
-			dev_info(&pdev->dev,
-				 "Trying to allocate %d MSI-X interrupt vectors\n",
-				 num_msix);
-			}
-		}
+	err = pci_enable_msix(pdev, adapter->msix_entries, num_msix);
+	if (err)
+		goto fail;
 
-		for (i = 0; i < num_msix; i++)
-			adapter->msix_entries[i].entry = i;
-		err = pci_enable_msix(pdev, adapter->msix_entries, num_msix);
-		if (err == 0) {
-			adapter->flags |= QLCNIC_MSIX_ENABLED;
-			if (qlcnic_83xx_check(adapter)) {
-				adapter->ahw->num_msix = num_msix;
-				/* subtract mail box and tx ring vectors */
-				adapter->max_sds_rings = num_msix -
-							 max_tx_rings - 1;
-			} else {
-				adapter->ahw->num_msix = num_msix;
-				if (qlcnic_check_multi_tx(adapter) &&
-				    !adapter->ahw->diag_test &&
-				    (adapter->max_drv_tx_rings > 1))
-					max_sds_rings = num_msix - max_tx_rings;
-				else
-					max_sds_rings = num_msix;
-
-				adapter->max_sds_rings = max_sds_rings;
-			}
-			dev_info(&pdev->dev, "using msi-x interrupts\n");
-		} else {
-fail:
-			dev_info(&pdev->dev,
-				 "Unable to allocate %d MSI-X interrupt vectors\n",
-				 num_msix);
-		}
+	adapter->flags |= QLCNIC_MSIX_ENABLED;
+	if (qlcnic_83xx_check(adapter)) {
+		adapter->ahw->num_msix = num_msix;
+		/* subtract mail box and tx ring vectors */
+		adapter->max_sds_rings = num_msix - max_tx_rings - 1;
+	} else {
+		adapter->ahw->num_msix = num_msix;
+		if (qlcnic_check_multi_tx(adapter) &&
+		    !adapter->ahw->diag_test && (adapter->max_drv_tx_rings > 1))
+			max_sds_rings = num_msix - max_tx_rings;
+		else
+			max_sds_rings = num_msix;
+
+		adapter->max_sds_rings = max_sds_rings;
 	}
 
+	dev_info(&pdev->dev, "using msi-x interrupts\n");
+	return 0;
+
+fail:
+	dev_info(&pdev->dev,
+		 "Unable to allocate %d MSI-X interrupt vectors\n", num_msix);
 	return err;
 }
 
-- 
1.7.7.6

[PATCH RFC 65/77] qlge: Remove a redundant assignment

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlge/qlge_main.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlge/qlge_main.c b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
index 2553cf4..ac54cb0 100644
--- a/drivers/net/ethernet/qlogic/qlge/qlge_main.c
+++ b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
@@ -3287,7 +3287,6 @@ static void ql_enable_msix(struct ql_adapter *qdev)
 			qdev->msi_x_entry = NULL;
 			netif_warn(qdev, ifup, qdev->ndev,
 				   "MSI-X Enable failed, trying MSI.\n");
-			qdev->intr_count = 1;
 			qlge_irq_type = MSI_IRQ;
 		} else if (err == 0) {
 			set_bit(QL_MSIX_ENABLED, &qdev->flags);
-- 
1.7.7.6

[PATCH RFC 66/77] qlge: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/qlogic/qlge/qlge_main.c |   39 +++++++++++--------------
 1 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlge/qlge_main.c b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
index ac54cb0..d6fdd93 100644
--- a/drivers/net/ethernet/qlogic/qlge/qlge_main.c
+++ b/drivers/net/ethernet/qlogic/qlge/qlge_main.c
@@ -3258,45 +3258,40 @@ static void ql_enable_msix(struct ql_adapter *qdev)
 
 	/* Get the MSIX vectors. */
 	if (qlge_irq_type == MSIX_IRQ) {
+		err = pci_msix_table_size(qdev->pdev);
+		if (err < 0)
+			goto msix_fail;
+
+		qdev->intr_count = min_t(u32, qdev->intr_count, err);
+
 		/* Try to alloc space for the msix struct,
 		 * if it fails then go to MSI/legacy.
 		 */
 		qdev->msi_x_entry = kcalloc(qdev->intr_count,
 					    sizeof(struct msix_entry),
 					    GFP_KERNEL);
-		if (!qdev->msi_x_entry) {
-			qlge_irq_type = MSI_IRQ;
-			goto msi;
-		}
+		if (!qdev->msi_x_entry)
+			goto msix_fail;
 
 		for (i = 0; i < qdev->intr_count; i++)
 			qdev->msi_x_entry[i].entry = i;
 
-		/* Loop to get our vectors.  We start with
-		 * what we want and settle for what we get.
-		 */
-		do {
-			err = pci_enable_msix(qdev->pdev,
-				qdev->msi_x_entry, qdev->intr_count);
-			if (err > 0)
-				qdev->intr_count = err;
-		} while (err > 0);
-
-		if (err < 0) {
-			kfree(qdev->msi_x_entry);
-			qdev->msi_x_entry = NULL;
-			netif_warn(qdev, ifup, qdev->ndev,
-				   "MSI-X Enable failed, trying MSI.\n");
-			qlge_irq_type = MSI_IRQ;
-		} else if (err == 0) {
+		if (!pci_enable_msix(qdev->pdev,
+				     qdev->msi_x_entry, qdev->intr_count)) {
 			set_bit(QL_MSIX_ENABLED, &qdev->flags);
 			netif_info(qdev, ifup, qdev->ndev,
 				   "MSI-X Enabled, got %d vectors.\n",
 				   qdev->intr_count);
 			return;
 		}
+
+		kfree(qdev->msi_x_entry);
+		qdev->msi_x_entry = NULL;
+msix_fail:
+		netif_warn(qdev, ifup, qdev->ndev,
+			   "MSI-X Enable failed, trying MSI.\n");
+		qlge_irq_type = MSI_IRQ;
 	}
-msi:
 	qdev->intr_count = 1;
 	if (qlge_irq_type == MSI_IRQ) {
 		if (!pci_enable_msi(qdev->pdev)) {
-- 
1.7.7.6

[PATCH RFC 67/77] rapidio: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/rapidio/devices/tsi721.c |   27 +++++++++++++++++----------
 1 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index ff7cbf2..5edd920 100644
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -734,6 +734,16 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 	int err;
 	int i;
 
+	err = pci_msix_table_size(priv->pdev);
+	if (err < 0)
+		goto err_out;
+	if (err < ARRAY_SIZE(entries)) {
+		dev_info(&priv->pdev->dev,
+			 "Only %d MSI-X vectors available, not using MSI-X\n",
+			 err);
+		return -ENOSPC;
+	}
+
 	entries[TSI721_VECT_IDB].entry = TSI721_MSIX_SR2PC_IDBQ_RCV(IDB_QUEUE);
 	entries[TSI721_VECT_PWRX].entry = TSI721_MSIX_SRIO_MAC_INT;
 
@@ -769,16 +779,8 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 #endif /* CONFIG_RAPIDIO_DMA_ENGINE */
 
 	err = pci_enable_msix(priv->pdev, entries, ARRAY_SIZE(entries));
-	if (err) {
-		if (err > 0)
-			dev_info(&priv->pdev->dev,
-				 "Only %d MSI-X vectors available, "
-				 "not using MSI-X\n", err);
-		else
-			dev_err(&priv->pdev->dev,
-				"Failed to enable MSI-X (err=%d)\n", err);
-		return err;
-	}
+	if (err)
+		goto err_out;
 
 	/*
 	 * Copy MSI-X vector information into tsi721 private structure
@@ -833,6 +835,11 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 #endif /* CONFIG_RAPIDIO_DMA_ENGINE */
 
 	return 0;
+
+err_out:
+	dev_err(&priv->pdev->dev,
+		"Failed to enable MSI-X (err=%d)\n", err);
+	return err;
 }
 #endif /* CONFIG_PCI_MSI */
 
-- 
1.7.7.6

[PATCH RFC 68/77] sfc: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/sfc/efx.c |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 07c9bc4..184ef9f 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1261,21 +1261,24 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 		n_channels += extra_channels;
 		n_channels = min(n_channels, efx->max_channels);
 
-		for (i = 0; i < n_channels; i++)
-			xentries[i].entry = i;
-		rc = pci_enable_msix(efx->pci_dev, xentries, n_channels);
-		if (rc > 0) {
+		rc = pci_msix_table_size(efx->pci_dev);
+		if (rc < 0)
+			goto msi;
+
+		if (rc < n_channels) {
 			netif_err(efx, drv, efx->net_dev,
 				  "WARNING: Insufficient MSI-X vectors"
 				  " available (%d < %u).\n", rc, n_channels);
 			netif_err(efx, drv, efx->net_dev,
 				  "WARNING: Performance may be reduced.\n");
-			EFX_BUG_ON_PARANOID(rc >= n_channels);
 			n_channels = rc;
-			rc = pci_enable_msix(efx->pci_dev, xentries,
-					     n_channels);
 		}
 
+		EFX_BUG_ON_PARANOID(n_channels > ARRAY_SIZE(xentries));
+		for (i = 0; i < n_channels; i++)
+			xentries[i].entry = i;
+
+		rc = pci_enable_msix(efx->pci_dev, xentries, n_channels);
 		if (rc == 0) {
 			efx->n_channels = n_channels;
 			if (n_channels > extra_channels)
@@ -1293,6 +1296,7 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 				efx_get_channel(efx, i)->irq =
 					xentries[i].vector;
 		} else {
+msi:
 			/* Fall back to single channel MSI */
 			efx->interrupt_mode = EFX_INT_MODE_MSI;
 			netif_err(efx, drv, efx->net_dev,
-- 
1.7.7.6

[PATCH RFC 69/77] tg3: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/broadcom/tg3.c |   24 +++++++++++++-----------
 1 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 12d961c..2e842ef3 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -11241,6 +11241,10 @@ static bool tg3_enable_msix(struct tg3 *tp)
 	int i, rc;
 	struct msix_entry msix_ent[TG3_IRQ_MAX_VECS];
 
+	rc = pci_msix_table_size(tp->pdev);
+	if (rc < 0)
+		return false;
+
 	tp->txq_cnt = tp->txq_req;
 	tp->rxq_cnt = tp->rxq_req;
 	if (!tp->rxq_cnt)
@@ -11256,6 +11260,14 @@ static bool tg3_enable_msix(struct tg3 *tp)
 		tp->txq_cnt = 1;
 
 	tp->irq_cnt = tg3_irq_count(tp);
+	if (tp->irq_cnt > rc) {
+		netdev_notice(tp->dev, "Requested %d MSI-Xs, available %d\n",
+			      tp->irq_cnt, rc);
+		tp->irq_cnt = rc;
+		tp->rxq_cnt = max(rc - 1, 1);
+		if (tp->txq_cnt)
+			tp->txq_cnt = min(tp->rxq_cnt, tp->txq_max);
+	}
 
 	for (i = 0; i < tp->irq_max; i++) {
 		msix_ent[i].entry  = i;
@@ -11263,18 +11275,8 @@ static bool tg3_enable_msix(struct tg3 *tp)
 	}
 
 	rc = pci_enable_msix(tp->pdev, msix_ent, tp->irq_cnt);
-	if (rc < 0) {
+	if (rc)
 		return false;
-	} else if (rc != 0) {
-		if (pci_enable_msix(tp->pdev, msix_ent, rc))
-			return false;
-		netdev_notice(tp->dev, "Requested %d MSI-X vectors, received %d\n",
-			      tp->irq_cnt, rc);
-		tp->irq_cnt = rc;
-		tp->rxq_cnt = max(rc - 1, 1);
-		if (tp->txq_cnt)
-			tp->txq_cnt = min(tp->rxq_cnt, tp->txq_max);
-	}
 
 	for (i = 0; i < tp->irq_max; i++)
 		tp->napi[i].irq_vec = msix_ent[i].vector;
-- 
1.7.7.6

[PATCH RFC 70/77] vmci: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/misc/vmw_vmci/vmci_guest.c |   22 +++++++++++++++-------
 1 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c
index b3a2b76..af5caf8 100644
--- a/drivers/misc/vmw_vmci/vmci_guest.c
+++ b/drivers/misc/vmw_vmci/vmci_guest.c
@@ -377,19 +377,27 @@ static int vmci_enable_msix(struct pci_dev *pdev,
 {
 	int i;
 	int result;
+	int nvec;
 
-	for (i = 0; i < VMCI_MAX_INTRS; ++i) {
+	result = pci_msix_table_size(pdev);
+	if (result < 0)
+		return result;
+
+	nvec = min(result, VMCI_MAX_INTRS);
+	if (nvec < VMCI_MAX_INTRS)
+		nvec = 1;
+
+	for (i = 0; i < nvec; ++i) {
 		vmci_dev->msix_entries[i].entry = i;
 		vmci_dev->msix_entries[i].vector = i;
 	}
 
-	result = pci_enable_msix(pdev, vmci_dev->msix_entries, VMCI_MAX_INTRS);
-	if (result == 0)
-		vmci_dev->exclusive_vectors = true;
-	else if (result > 0)
-		result = pci_enable_msix(pdev, vmci_dev->msix_entries, 1);
+	result = pci_enable_msix(pdev, vmci_dev->msix_entries, nvec);
+	if (result)
+		return result;
 
-	return result;
+	vmci_dev->exclusive_vectors = true;
+	return 0;
 }
 
 /*
-- 
1.7.7.6

[PATCH RFC 71/77] vmxnet3: Return -EINVAL if number of requested MSI-Xs is not enough

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 7e2788c..5b8ea71 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2738,7 +2738,7 @@ static int
 vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
 			     int vectors)
 {
-	int err = 0, vector_threshold;
+	int err = -EINVAL, vector_threshold;
 	vector_threshold = VMXNET3_LINUX_MIN_MSIX_VECT;
 
 	while (vectors >= vector_threshold) {
-- 
1.7.7.6

[PATCH RFC 72/77] vmxnet3: Fixup a weird loop exit

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 5b8ea71..3518173 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2750,7 +2750,7 @@ vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
 		} else if (err < 0) {
 			dev_err(&adapter->netdev->dev,
 				   "Failed to enable MSI-X, error: %d\n", err);
-			vectors = 0;
+			return err;
 		} else if (err < vector_threshold) {
 			break;
 		} else {
-- 
1.7.7.6

[PATCH RFC 73/77] vmxnet3: Return -ENOSPC when not enough MSI-X vectors available

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3518173..3df7f32 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2752,7 +2752,10 @@ vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
 				   "Failed to enable MSI-X, error: %d\n", err);
 			return err;
 		} else if (err < vector_threshold) {
-			break;
+			dev_info(&adapter->pdev->dev,
+				 "Number of MSI-Xs which can be allocated "
+				 "is lower than min threshold required.\n");
+			return -ENOSPC;
 		} else {
 			/* If fails to enable required number of MSI-x vectors
 			 * try enabling minimum number of vectors required.
@@ -2764,9 +2767,6 @@ vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
 		}
 	}
 
-	dev_info(&adapter->pdev->dev,
-		 "Number of MSI-X interrupts which can be allocated "
-		 "is lower than min threshold required.\n");
 	return err;
 }
 
-- 
1.7.7.6

[PATCH RFC 74/77] vmxnet3: Limit number of rx queues to 1 if per-queue MSI-Xs failed

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3df7f32..00dc0d0 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2814,12 +2814,14 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 
 		err = vmxnet3_acquire_msix_vectors(adapter,
 						   adapter->intr.num_intrs);
-		/* If we cannot allocate one MSIx vector per queue
-		 * then limit the number of rx queues to 1
-		 */
-		if (err == VMXNET3_LINUX_MIN_MSIX_VECT) {
-			if (adapter->share_intr != VMXNET3_INTR_BUDDYSHARE
-			    || adapter->num_rx_queues != 1) {
+		if (!err) {
+			/* If we cannot allocate one MSIx vector per queue
+			 * then limit the number of rx queues to 1
+			 */
+			if ((adapter->intr.num_intrs ==
+			     VMXNET3_LINUX_MIN_MSIX_VECT) &&
+			    ((adapter->share_intr != VMXNET3_INTR_BUDDYSHARE) ||
+			     (adapter->num_rx_queues != 1))) {
 				adapter->share_intr = VMXNET3_INTR_TXSHARE;
 				netdev_err(adapter->netdev,
 					   "Number of rx queues : 1\n");
@@ -2829,8 +2831,6 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 			}
 			return;
 		}
-		if (!err)
-			return;
 
 		/* If we cannot allocate MSIx vectors use only one rx queue */
 		dev_info(&adapter->pdev->dev,
-- 
1.7.7.6

[PATCH RFC 75/77] vmxnet3: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c |   68 ++++++++++++++++++-------------------
 1 files changed, 33 insertions(+), 35 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 00dc0d0..8d3321b 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2724,49 +2724,47 @@ vmxnet3_read_mac_addr(struct vmxnet3_adapter *adapter, u8 *mac)
 
 #ifdef CONFIG_PCI_MSI
 
-/*
- * Enable MSIx vectors.
- * Returns :
- *	0 on successful enabling of required vectors,
- *	VMXNET3_LINUX_MIN_MSIX_VECT when only minimum number of vectors required
- *	 could be enabled.
- *	number of vectors which can be enabled otherwise (this number is smaller
- *	 than VMXNET3_LINUX_MIN_MSIX_VECT)
- */
-
 static int
 vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
 			     int vectors)
 {
-	int err = -EINVAL, vector_threshold;
+	int err, vector_threshold;
+
 	vector_threshold = VMXNET3_LINUX_MIN_MSIX_VECT;
+	if (vectors < vector_threshold)
+		return -EINVAL;
 
-	while (vectors >= vector_threshold) {
-		err = pci_enable_msix(adapter->pdev, adapter->intr.msix_entries,
-				      vectors);
-		if (!err) {
-			adapter->intr.num_intrs = vectors;
-			return 0;
-		} else if (err < 0) {
-			dev_err(&adapter->netdev->dev,
-				   "Failed to enable MSI-X, error: %d\n", err);
-			return err;
-		} else if (err < vector_threshold) {
-			dev_info(&adapter->pdev->dev,
-				 "Number of MSI-Xs which can be allocated "
-				 "is lower than min threshold required.\n");
-			return -ENOSPC;
-		} else {
-			/* If fails to enable required number of MSI-x vectors
-			 * try enabling minimum number of vectors required.
-			 */
-			dev_err(&adapter->netdev->dev,
-				"Failed to enable %d MSI-X, trying %d instead\n",
-				    vectors, vector_threshold);
-			vectors = vector_threshold;
-		}
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		goto err_msix;
+	if (err < vector_threshold) {
+		dev_info(&adapter->pdev->dev,
+			 "Number of MSI-X interrupts which can be allocated "
+			 "is lower than min threshold required.\n");
+		return -ENOSPC;
+	}
+	if (err < vectors) {
+		/*
+		 * If fails to enable required number of MSI-x vectors
+		 * try enabling minimum number of vectors required.
+		 */
+		dev_err(&adapter->netdev->dev,
+			"Failed to enable %d MSI-X, trying %d instead\n",
+			vectors, vector_threshold);
+		vectors = vector_threshold;
 	}
 
+	err = pci_enable_msix(adapter->pdev, adapter->intr.msix_entries,
+			      vectors);
+	if (err)
+		goto err_msix;
+
+	adapter->intr.num_intrs = vectors;
+	return 0;
+
+err_msix:
+	dev_err(&adapter->netdev->dev,
+		"Failed to enable MSI-X, error: %d\n", err);
 	return err;
 }
 
-- 
1.7.7.6

[PATCH RFC 76/77] vxge: Sanitize MSI-X allocation routine error codes

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/neterion/vxge/vxge-main.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
index 5a20eaf..b81ff8b 100644
--- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
+++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
@@ -2352,7 +2352,7 @@ start:
 			"%s: MSI-X enable failed for %d vectors, ret: %d",
 			VXGE_DRIVER_NAME, vdev->intr_cnt, ret);
 		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
-			ret = -ENODEV;
+			ret = -ENOSPC;
 			goto enable_msix_failed;
 		}
 
@@ -2365,10 +2365,8 @@ start:
 		vxge_close_vpaths(vdev, temp);
 		vdev->no_of_vpath = temp;
 		goto start;
-	} else if (ret < 0) {
-		ret = -ENODEV;
+	} else if (ret < 0)
 		goto enable_msix_failed;
-	}
 	return 0;
 
 enable_msix_failed:
-- 
1.7.7.6

[PATCH RFC 77/77] vxge: Update MSI/MSI-X interrupts enablement code

[Alexander Gordeev]

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
 drivers/net/ethernet/neterion/vxge/vxge-main.c |   36 ++++++++++-------------
 1 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
index b81ff8b..b4d40dd 100644
--- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
+++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
@@ -2297,7 +2297,21 @@ static int vxge_alloc_msix(struct vxgedev *vdev)
 	int msix_intr_vect = 0, temp;
 	vdev->intr_cnt = 0;
 
-start:
+	ret = pci_msix_table_size(vdev->pdev);
+	if (ret < 0)
+		goto alloc_entries_failed;
+
+	if (ret < (vdev->no_of_vpath * 2 + 1)) {
+		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
+			ret = -ENOSPC;
+			goto alloc_entries_failed;
+		}
+		/* Try with less no of vector by reducing no of vpaths count */
+		temp = (ret - 1)/2;
+		vxge_close_vpaths(vdev, temp);
+		vdev->no_of_vpath = temp;
+	}
+
 	/* Tx/Rx MSIX Vectors count */
 	vdev->intr_cnt = vdev->no_of_vpath * 2;
 
@@ -2347,25 +2361,7 @@ start:
 	vdev->vxge_entries[j].in_use = 0;
 
 	ret = pci_enable_msix(vdev->pdev, vdev->entries, vdev->intr_cnt);
-	if (ret > 0) {
-		vxge_debug_init(VXGE_ERR,
-			"%s: MSI-X enable failed for %d vectors, ret: %d",
-			VXGE_DRIVER_NAME, vdev->intr_cnt, ret);
-		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
-			ret = -ENOSPC;
-			goto enable_msix_failed;
-		}
-
-		kfree(vdev->entries);
-		kfree(vdev->vxge_entries);
-		vdev->entries = NULL;
-		vdev->vxge_entries = NULL;
-		/* Try with less no of vector by reducing no of vpaths count */
-		temp = (ret - 1)/2;
-		vxge_close_vpaths(vdev, temp);
-		vdev->no_of_vpath = temp;
-		goto start;
-	} else if (ret < 0)
+	if (ret)
 		goto enable_msix_failed;
 	return 0;
 
-- 
1.7.7.6

Re: [PATCH RFC 77/77] vxge: Update MSI/MSI-X interrupts enablement code

[Jon Mason]

On Wed, Oct 02, 2013 at 12:49:33PM +0200, Alexander Gordeev wrote:
> As result of recent re-design of the MSI/MSI-X interrupts enabling
> pattern this driver has to be updated to use the new technique to
> obtain a optimal number of MSI/MSI-X interrupts required.
> 
> Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> ---
>  drivers/net/ethernet/neterion/vxge/vxge-main.c |   36 ++++++++++-------------
>  1 files changed, 16 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
> index b81ff8b..b4d40dd 100644
> --- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
> +++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
> @@ -2297,7 +2297,21 @@ static int vxge_alloc_msix(struct vxgedev *vdev)
>  	int msix_intr_vect = 0, temp;
>  	vdev->intr_cnt = 0;
>  
> -start:
> +	ret = pci_msix_table_size(vdev->pdev);
> +	if (ret < 0)
> +		goto alloc_entries_failed;
> +
> +	if (ret < (vdev->no_of_vpath * 2 + 1)) {
> +		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
> +			ret = -ENOSPC;
> +			goto alloc_entries_failed;
> +		}
> +		/* Try with less no of vector by reducing no of vpaths count */
> +		temp = (ret - 1)/2;
> +		vxge_close_vpaths(vdev, temp);
> +		vdev->no_of_vpath = temp;
> +	}

The original code was ugly (not my code, so I can say that).  I'd like
to see it a little stream lined.  Something like:


        vdev->intr_cnt = pci_msix_table_size(vdev->pdev);

        if (vdev->intr_cnt % 2 == 0)
                vdev->intr_cnt--;

        if (vdev->intr_cnt < 3 || max_config_vpath != VXGE_USE_DEFAULT)
                goto alloc_entries_failed;

        if (vdev->intr_cnt != vdev->no_of_vpath * 2 + 1) {
                vxge_close_vpaths(vdev, vdev->intr_cnt / 2);
                vdev->no_of_vpath = vdev->intr_cnt / 2;
        }


> +
>  	/* Tx/Rx MSIX Vectors count */
>  	vdev->intr_cnt = vdev->no_of_vpath * 2;
>  
> @@ -2347,25 +2361,7 @@ start:
>  	vdev->vxge_entries[j].in_use = 0;
>  
>  	ret = pci_enable_msix(vdev->pdev, vdev->entries, vdev->intr_cnt);
> -	if (ret > 0) {
> -		vxge_debug_init(VXGE_ERR,
> -			"%s: MSI-X enable failed for %d vectors, ret: %d",
> -			VXGE_DRIVER_NAME, vdev->intr_cnt, ret);
> -		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
> -			ret = -ENOSPC;
> -			goto enable_msix_failed;
> -		}
> -
> -		kfree(vdev->entries);
> -		kfree(vdev->vxge_entries);
> -		vdev->entries = NULL;
> -		vdev->vxge_entries = NULL;
> -		/* Try with less no of vector by reducing no of vpaths count */
> -		temp = (ret - 1)/2;
> -		vxge_close_vpaths(vdev, temp);
> -		vdev->no_of_vpath = temp;
> -		goto start;
> -	} else if (ret < 0)
> +	if (ret)
>  		goto enable_msix_failed;

Nit, space here please.

>  	return 0;
>  
> -- 
> 1.7.7.6
> 

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Thu, Oct 03, 2013 at 11:49:45PM +0100, Ben Hutchings wrote:
> On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> > This update converts pci_enable_msix() and pci_enable_msi_block()
> > interfaces to canonical kernel functions and makes them return a
> > error code in case of failure or 0 in case of success.
> [...]
> 
> I think this is fundamentally flawed: pci_msix_table_size() and
> pci_get_msi_cap() can only report the limits of the *device* (which the
> driver usually already knows), whereas MSI allocation can also be
> constrained due to *global* limits on the number of distinct IRQs.

Even the current implementation by no means addresses it. Although it
might seem a case for architectures to report the number of IRQs available
for a driver to retry, in fact they all just fail. The same applies to
*any* other type of resource involved: irq_desc's, CPU interrupt vector
space, msi_desc's etc. No platform cares about it and just bails out once
a constrain met (please correct me if I am wrong here). Given that Linux
has been doing well even on embedded I think we should not change it.

The only exception to the above is pSeries platform which takes advantage
of the current design (to implement MSI quota). There are indications we
can satisfy pSeries requirements, but the design proposed in this RFC
is not going to change drastically anyway. The start of the discusstion
is here: https://lkml.org/lkml/2013/9/5/293

> Currently pci_enable_msix() will report a positive value if it fails due
> to the global limit.  Your patch 7 removes that.  pci_enable_msi_block()
> unfortunately doesn't appear to do this.

pci_enable_msi_block() can do more than one MSI only on x86 (with IOMMU),
but it does not bother to return positive numbers, indeed.

> It seems to me that a more useful interface would take a minimum and
> maximum number of vectors from the driver.  This wouldn't allow the
> driver to specify that it could only accept, say, any even number within
> a certain range, but you could still leave the current functions
> available for any driver that needs that.

Mmmm.. I am not sure I am getting it. Could you please rephrase?

> Ben.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[David Laight]

> > It seems to me that a more useful interface would take a minimum and
> > maximum number of vectors from the driver.  This wouldn't allow the
> > driver to specify that it could only accept, say, any even number within
> > a certain range, but you could still leave the current functions
> > available for any driver that needs that.
> 
> Mmmm.. I am not sure I am getting it. Could you please rephrase?

One possibility is for drivers than can use a lot of interrupts to
request a minimum number initially and then request the additional
ones much later on.
That would make it less likely that none will be available for
devices/drivers that need them but are initialised later.

	David




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Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Fri, Oct 04, 2013 at 09:31:49AM +0100, David Laight wrote:
> > Mmmm.. I am not sure I am getting it. Could you please rephrase?
> 
> One possibility is for drivers than can use a lot of interrupts to
> request a minimum number initially and then request the additional
> ones much later on.
> That would make it less likely that none will be available for
> devices/drivers that need them but are initialised later.

It sounds as a whole new topic for me. Isn't it?

Anyway, what prevents the above from being done with pci_enable_msix(nvec1) -
pci_disable_msix() - pci_enable_msix(nvec2) where nvec1 < nvec2?

> 	David

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Ben Hutchings]

On Fri, 2013-10-04 at 10:29 +0200, Alexander Gordeev wrote:
> On Thu, Oct 03, 2013 at 11:49:45PM +0100, Ben Hutchings wrote:
> > On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> > > This update converts pci_enable_msix() and pci_enable_msi_block()
> > > interfaces to canonical kernel functions and makes them return a
> > > error code in case of failure or 0 in case of success.
> > [...]
> > 
> > I think this is fundamentally flawed: pci_msix_table_size() and
> > pci_get_msi_cap() can only report the limits of the *device* (which the
> > driver usually already knows), whereas MSI allocation can also be
> > constrained due to *global* limits on the number of distinct IRQs.
> 
> Even the current implementation by no means addresses it. Although it
> might seem a case for architectures to report the number of IRQs available
> for a driver to retry, in fact they all just fail. The same applies to
> *any* other type of resource involved: irq_desc's, CPU interrupt vector
> space, msi_desc's etc. No platform cares about it and just bails out once
> a constrain met (please correct me if I am wrong here). Given that Linux
> has been doing well even on embedded I think we should not change it.
>
> The only exception to the above is pSeries platform which takes advantage
> of the current design (to implement MSI quota). There are indications we
> can satisfy pSeries requirements, but the design proposed in this RFC
> is not going to change drastically anyway. The start of the discusstion
> is here: https://lkml.org/lkml/2013/9/5/293

All I can see there is that Tejun didn't think that the global limits
and positive return values were implemented by any architecture.  But
you have a counter-example, so I'm not sure what your point is.

It has been quite a while since I saw this happen on x86.  But I just
checked on a test system running RHEL 5 i386 (Linux 2.6.18).  If I ask
for 16 MSI-X vectors on a device that supports 1024, the return value is
8, and indeed I can then successfully allocate 8.

Now that's going quite a way back, and it may be that global limits
aren't a significant problem any more.  With the x86_64 build of RHEL 5
on an identical system, I can allocate 16 or even 32, so this is
apparently not a hardware limit in this case.

> > Currently pci_enable_msix() will report a positive value if it fails due
> > to the global limit.  Your patch 7 removes that.  pci_enable_msi_block()
> > unfortunately doesn't appear to do this.
> 
> pci_enable_msi_block() can do more than one MSI only on x86 (with IOMMU),
> but it does not bother to return positive numbers, indeed.
> 
> > It seems to me that a more useful interface would take a minimum and
> > maximum number of vectors from the driver.  This wouldn't allow the
> > driver to specify that it could only accept, say, any even number within
> > a certain range, but you could still leave the current functions
> > available for any driver that needs that.
> 
> Mmmm.. I am not sure I am getting it. Could you please rephrase?

Most drivers seem to either:
(a) require exactly a certain number of MSI vectors, or
(b) require a minimum number of MSI vectors, usually want to allocate
more, and work with any number in between

We can support drivers in both classes by adding new allocation
functions that allow specifying a minimum (required) and maximum
(wanted) number of MSI vectors.  Those in class (a) would just specify
the same value for both.  These new functions can take account of any
global limit or allocation policy without any further changes to the
drivers that use them.

The few drivers with more specific requirements would still need to
implement the currently recommended loop, using the old allocation
functions.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Fri, Oct 04, 2013 at 10:29:16PM +0100, Ben Hutchings wrote:
> On Fri, 2013-10-04 at 10:29 +0200, Alexander Gordeev wrote:
> All I can see there is that Tejun didn't think that the global limits
> and positive return values were implemented by any architecture.

I would say more than just that :) I picked few quotes which in my
reading represent the guys positions:

Tejun Heo: "...do we really
care about possible partial success?  This sort of interface is
unnecessarily complex and actively harmful.  It forces all users to
wonder what could possibly happen and implement all sorts of nutty
fallback logic which is highly likely to be error-prone on both the
software and hardware side.  Seriously, how much testing would such
code path would get both on the driver and firmware sides?"

Bjorn Helgaas: "I agree, that would be much simpler.
I propose that you rework it that way, and at least find out what
(if anything) would break if we do that."

Michael Ellerman: "I really think you're overstating the complexity here.
Functions typically return a boolean   -> nothing to see here
This function returns a tristate value -> brain explosion!";
"All a lot of bother for no real gain IMHO."

> But you have a counter-example, so I'm not sure what your point is.

I concur with Tejun. I think we need to get rid of the loop.

As of the counter-example I think we could honour the pSeries quota by
inroducing an interface to interrogate what you call global limits -
pci_get_msix_limit(), i.e.:

	rc = pci_msix_table_size(pdev, nvec);
	if (rc < 0)
		return rc;

	nvec = min(rc, nvec);

	rc = pci_get_msix_limit(pdev, nvec);
	if (rc < 0)
		return rc;

	nvec = min(rc, nvec);

	for (i = 0; i < nvec; i++)
		msix_entry[i].entry = i;

	rc = pci_enable_msix(pdev, msix_entry, nvec);
	if (rc)
		return rc;

The latest state of those discussion is somewhere around Michael's:
"We could probably make that work." and Tejun's: "Are we talking about
some limited number of device drivers here? Also, is the quota still
necessary for machines in production today?"

So my point is - drivers should first obtain a number of MSIs they *can*
get, then *derive* a number of MSIs the device is fine with and only then
request that number. Not terribly different from memory or any other type
of resource allocation ;)

> It has been quite a while since I saw this happen on x86.  But I just
> checked on a test system running RHEL 5 i386 (Linux 2.6.18).  If I ask
> for 16 MSI-X vectors on a device that supports 1024, the return value is
> 8, and indeed I can then successfully allocate 8.
> 
> Now that's going quite a way back, and it may be that global limits
> aren't a significant problem any more.  With the x86_64 build of RHEL 5
> on an identical system, I can allocate 16 or even 32, so this is
> apparently not a hardware limit in this case.

Well, I do not know how to comment here. 2.6.18 has a significantly
different codebase wrt MSIs. What about a recent version?

> Most drivers seem to either:
> (a) require exactly a certain number of MSI vectors, or
> (b) require a minimum number of MSI vectors, usually want to allocate
> more, and work with any number in between
> 
> We can support drivers in both classes by adding new allocation
> functions that allow specifying a minimum (required) and maximum
> (wanted) number of MSI vectors.  Those in class (a) would just specify
> the same value for both.  These new functions can take account of any
> global limit or allocation policy without any further changes to the
> drivers that use them.

I think such interface is redundant wrt the current pci_enable_msix()
implementation.. and you propose to leave it. IMO it unnecessarily blows
the generic MSI API with no demand from drivers.

> The few drivers with more specific requirements would still need to
> implement the currently recommended loop, using the old allocation
> functions.

Although the classes of drivers you specified indeed exist, I do believe
just a single interface is enough to handle them all.

> Ben.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Benjamin Herrenschmidt]

On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> So my point is - drivers should first obtain a number of MSIs they *can*
> get, then *derive* a number of MSIs the device is fine with and only then
> request that number. Not terribly different from memory or any other type
> of resource allocation ;)

What if the limit is for a group of devices ? Your interface is racy in
that case, another driver could have eaten into the limit in between the
calls.

Ben.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Sun, Oct 06, 2013 at 08:46:26AM +1100, Benjamin Herrenschmidt wrote:
> On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> > So my point is - drivers should first obtain a number of MSIs they *can*
> > get, then *derive* a number of MSIs the device is fine with and only then
> > request that number. Not terribly different from memory or any other type
> > of resource allocation ;)
> 
> What if the limit is for a group of devices ? Your interface is racy in
> that case, another driver could have eaten into the limit in between the
> calls.

Well, the another driver has had a better karma ;) But seriously, the
current scheme with a loop is not race-safe wrt to any other type of
resource which might exhaust. What makes the quota so special so we
should care about it and should not care i.e. about lack of msi_desc's?

Yeah, I know the quota might hit more likely. But why it is not addressed
right now then? Not a single function in chains...
  rtas_msi_check_device() -> msi_quota_for_device() -> traverse_pci_devices()
  rtas_setup_msi_irqs() -> msi_quota_for_device() -> traverse_pci_devices()
...is race-safe. So if it has not been bothering anyone until now then
no reason to start worrying now :)

In fact, in the current design to address the quota race decently the
drivers would have to protect the *loop* to prevent the quota change
between a pci_enable_msix() returned a positive number and the the next
call to pci_enable_msix() with that number. Is it doable?

> Ben.
> 
> 

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Benjamin Herrenschmidt]

On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> On Sun, Oct 06, 2013 at 08:46:26AM +1100, Benjamin Herrenschmidt wrote:
> > On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> > > So my point is - drivers should first obtain a number of MSIs they *can*
> > > get, then *derive* a number of MSIs the device is fine with and only then
> > > request that number. Not terribly different from memory or any other type
> > > of resource allocation ;)
> > 
> > What if the limit is for a group of devices ? Your interface is racy in
> > that case, another driver could have eaten into the limit in between the
> > calls.
> 
> Well, the another driver has had a better karma ;) But seriously, the
> current scheme with a loop is not race-safe wrt to any other type of
> resource which might exhaust. What makes the quota so special so we
> should care about it and should not care i.e. about lack of msi_desc's?

I'm not saying the current scheme is better but I prefer the option of
passing a min,max to the request function.

> Yeah, I know the quota might hit more likely. But why it is not addressed
> right now then? Not a single function in chains...
>   rtas_msi_check_device() -> msi_quota_for_device() -> traverse_pci_devices()
>   rtas_setup_msi_irqs() -> msi_quota_for_device() -> traverse_pci_devices()
> ...is race-safe. So if it has not been bothering anyone until now then 
> no reason to start worrying now :)
>
> In fact, in the current design to address the quota race decently the
> drivers would have to protect the *loop* to prevent the quota change
> between a pci_enable_msix() returned a positive number and the the next
> call to pci_enable_msix() with that number. Is it doable?

I am not advocating for the current design, simply saying that your
proposal doesn't address this issue while Ben's does.

Cheers,
Ben.

> > Ben.
> > 
> > 
> 

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Sun, Oct 06, 2013 at 05:19:46PM +1100, Benjamin Herrenschmidt wrote:
> On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> > In fact, in the current design to address the quota race decently the
> > drivers would have to protect the *loop* to prevent the quota change
> > between a pci_enable_msix() returned a positive number and the the next
> > call to pci_enable_msix() with that number. Is it doable?
> 
> I am not advocating for the current design, simply saying that your
> proposal doesn't address this issue while Ben's does.

There is one major flaw in min-max approach - the generic MSI layer
will have to take decisions on exact number of MSIs to request, not
device drivers.

This will never work for all devices, because there might be specific
requirements which are not covered by the min-max. That is what Ben
described "...say, any even number within a certain range". Ben suggests
to leave the existing loop scheme to cover such devices, which I think is
not right.

What about introducing pci_lock_msi() and pci_unlock_msi() and let device
drivers care about their ranges and specifics in race-safe manner?
I do not call to introduce it right now (since it appears pSeries has not
been hitting the race for years) just as a possible alternative to Ben's
proposal.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Benjamin Herrenschmidt]

On Mon, 2013-10-07 at 14:01 -0400, Tejun Heo wrote:
> I don't think the same race condition would happen with the loop.  The
> problem case is where multiple msi(x) allocation fails completely
> because the global limit went down before inquiry and allocation.  In
> the loop based interface, it'd retry with the lower number.
> 
> As long as the number of drivers which need this sort of adaptive
> allocation isn't too high and the common cases can be made simple, I
> don't think the "complex" part of interface is all that important.
> Maybe we can have reserve / cancel type interface or just keep the
> loop with more explicit function names (ie. try_enable or something
> like that).

I'm thinking a better API overall might just have been to request
individual MSI-X one by one :-)

We want to be able to request an MSI-X at runtime anyway ... if I want
to dynamically add a queue to my network interface, I want it to be able
to pop a new arbitrary MSI-X.

And we don't want to lock drivers into contiguous MSI-X sets either.

And for the cleanup ... well that's what the "pcim" functions are for,
we can just make MSI-X variants.

Ben.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Ben Hutchings]

On Tue, 2013-10-08 at 07:10 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2013-10-07 at 14:01 -0400, Tejun Heo wrote:
> > I don't think the same race condition would happen with the loop.  The
> > problem case is where multiple msi(x) allocation fails completely
> > because the global limit went down before inquiry and allocation.  In
> > the loop based interface, it'd retry with the lower number.
> > 
> > As long as the number of drivers which need this sort of adaptive
> > allocation isn't too high and the common cases can be made simple, I
> > don't think the "complex" part of interface is all that important.
> > Maybe we can have reserve / cancel type interface or just keep the
> > loop with more explicit function names (ie. try_enable or something
> > like that).
> 
> I'm thinking a better API overall might just have been to request
> individual MSI-X one by one :-)
> 
> We want to be able to request an MSI-X at runtime anyway ... if I want
> to dynamically add a queue to my network interface, I want it to be able
> to pop a new arbitrary MSI-X.

Yes, this would be very useful.

> And we don't want to lock drivers into contiguous MSI-X sets either.

I don't think there's any such limitation now.  The entries array passed
to pci_enable_msix() specifies which MSI-X vectors the driver wants to
enable.  It's usually filled with 0..nvec-1 in order, but not always.
And the IRQ numbers returned aren't usually contiguous either, on x86.

Ben.

> And for the cleanup ... well that's what the "pcim" functions are for,
> we can just make MSI-X variants.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [E1000-devel] [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Waskiewicz Jr, Peter P]

On Tue, 2013-10-08 at 07:10 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2013-10-07 at 14:01 -0400, Tejun Heo wrote:
> > I don't think the same race condition would happen with the loop.  The
> > problem case is where multiple msi(x) allocation fails completely
> > because the global limit went down before inquiry and allocation.  In
> > the loop based interface, it'd retry with the lower number.
> > 
> > As long as the number of drivers which need this sort of adaptive
> > allocation isn't too high and the common cases can be made simple, I
> > don't think the "complex" part of interface is all that important.
> > Maybe we can have reserve / cancel type interface or just keep the
> > loop with more explicit function names (ie. try_enable or something
> > like that).
> 
> We want to be able to request an MSI-X at runtime anyway ... if I want
> to dynamically add a queue to my network interface, I want it to be able
> to pop a new arbitrary MSI-X.

If you want to dynamically allocate another queue, you'd either need to
have them all pre-allocated at alloc_etherdev_mqs(), or add a new API to
netdev that allows adding new queues on the fly.

How things are done today, the Tx queues are all tacked onto the end of
the netdev struct.  That would have to change to probably a linked list
of queues that could be grown or shrunk on the fly.
netif_alloc_netdev_queues() would need to change the kzalloc() to a list
allocation.

Cheers,
-PJ

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> > What about introducing pci_lock_msi() and pci_unlock_msi() and let device
> > drivers care about their ranges and specifics in race-safe manner?
> > I do not call to introduce it right now (since it appears pSeries has not
> > been hitting the race for years) just as a possible alternative to Ben's
> > proposal.
> 
> I don't think the same race condition would happen with the loop.

We need to distinguish the contexts we're discussing.

If we talk about pSeries quota, then the current pSeries pci_enable_msix()
implementation is racy internally and could fail if the quota went down
*while* pci_enable_msix() is executing. In this case the loop will have to
exit rather than retry with a lower number (what number?).

In this regard the new scheme does not bring anything new and relies on
the fact this race does not hit and therefore does not worry.

If we talk about quota as it has to be, then yes - the loop scheme seems
more preferable.

Overall, looks like we just need to fix the pSeries implementation,
if the guys want it, he-he :)

> The problem case is where multiple msi(x) allocation fails completely
> because the global limit went down before inquiry and allocation.  In
> the loop based interface, it'd retry with the lower number.

I am probably missing something here. If the global limit went down before
inquiry then the inquiry will get what is available and try to allocate with
than number.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello,

On Tue, Oct 08, 2013 at 02:22:16PM +0200, Alexander Gordeev wrote:
> If we talk about pSeries quota, then the current pSeries pci_enable_msix()
> implementation is racy internally and could fail if the quota went down
> *while* pci_enable_msix() is executing. In this case the loop will have to
> exit rather than retry with a lower number (what number?).

Ah, okay, so that one is already broken.

> In this regard the new scheme does not bring anything new and relies on
> the fact this race does not hit and therefore does not worry.
> 
> If we talk about quota as it has to be, then yes - the loop scheme seems
> more preferable.
> 
> Overall, looks like we just need to fix the pSeries implementation,
> if the guys want it, he-he :)

If we can't figure out a better interface for the retry case, I think
what can really help is having a simple interface for the simpler
cases.

> > The problem case is where multiple msi(x) allocation fails completely
> > because the global limit went down before inquiry and allocation.  In
> > the loop based interface, it'd retry with the lower number.
> 
> I am probably missing something here. If the global limit went down before
> inquiry then the inquiry will get what is available and try to allocate with
> than number.

Oh, I should have written between inquiry and allocation.  Sorry.

Thanks.

-- 
tejun

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> Hmmm... yean, the race condition could be an issue as multiple msi
> allocation might fail even if the driver can and explicitly handle
> multiple allocation if the quota gets reduced inbetween.

BTW, should we care about the quota getting increased inbetween?
That would entail.. kind of pci_get_msi_limit() :), but IMHO it is
not worth it.

> tejun

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello,

On Wed, Oct 09, 2013 at 02:57:16PM +0200, Alexander Gordeev wrote:
> On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> > Hmmm... yean, the race condition could be an issue as multiple msi
> > allocation might fail even if the driver can and explicitly handle
> > multiple allocation if the quota gets reduced inbetween.
> 
> BTW, should we care about the quota getting increased inbetween?
> That would entail.. kind of pci_get_msi_limit() :), but IMHO it is
> not worth it.

I think we shouldn't.  If the resource was low during a point in time
during allocation, it's fine to base the result on that - the resource
was actually low and which answer we return is just a question of
timing and both are correct.  The only reason the existing race
condition is problematic is because it may fail even if the resource
never falls below the failure point.

Thanks.

-- 
tejun

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

On Mon, Oct 07, 2013 at 09:48:01PM +0100, Ben Hutchings wrote:
> > There is one major flaw in min-max approach - the generic MSI layer
> > will have to take decisions on exact number of MSIs to request, not
> > device drivers.
> [...
> 
> No, the min-max functions should be implemented using the same loop that
> drivers are expected to use now.

Wheee... earlier in the thread I thought you guys were referring to
yourselves in the third person and was getting a bit worried. :)

-- 
tejun

Re: [PATCH RFC 07/77] PCI/MSI: Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello,

On Wed, Oct 02, 2013 at 12:48:23PM +0200, Alexander Gordeev wrote:
> +static int foo_driver_enable_msi(struct foo_adapter *adapter, int nvec)
> +{
> +	rc = pci_get_msi_cap(adapter->pdev);
> +	if (rc < 0)
> +		return rc;
> +
> +	nvec = min(nvec, rc);
> +	if (nvec < FOO_DRIVER_MINIMUM_NVEC) {
> +		return -ENOSPC;
> +
> +	rc = pci_enable_msi_block(adapter->pdev, nvec);
> +	return rc;
> +}

If there are many which duplicate the above pattern, it'd probably be
worthwhile to provide a helper?  It's usually a good idea to reduce
the amount of boilerplate code in drivers.

>  static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
>  {
> +	rc = pci_msix_table_size(adapter->pdev);
> +	if (rc < 0)
> +		return rc;
> +
> +	nvec = min(nvec, rc);
> +	if (nvec < FOO_DRIVER_MINIMUM_NVEC) {
> +		return -ENOSPC;
> +
> +	for (i = 0; i < nvec; i++)
> +		adapter->msix_entries[i].entry = i;
> +
> +	rc = pci_enable_msix(adapter->pdev, adapter->msix_entries, nvec);
> +	return rc;
>  }

Ditto.

> @@ -975,7 +951,7 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
>  	if (nr_entries < 0)
>  		return nr_entries;
>  	if (nvec > nr_entries)
> -		return nr_entries;
> +		return -EINVAL;
>  
>  	/* Check for any invalid entries */
>  	for (i = 0; i < nvec; i++) {

If we do things this way, it breaks all drivers using this interface
until they're converted, right?  Also, it probably isn't the best idea
to flip the behavior like this as this can go completely unnoticed (no
compiler warning or anything, the same function just behaves
differently).  Maybe it'd be a better idea to introduce a simpler
interface that most can be converted to?

Thanks.

-- 
tejun

Re: [PATCH RFC 07/77] PCI/MSI: Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 02:17:49PM -0400, Tejun Heo wrote:
> Hello,
> 
> On Wed, Oct 02, 2013 at 12:48:23PM +0200, Alexander Gordeev wrote:
> > +static int foo_driver_enable_msi(struct foo_adapter *adapter, int nvec)
> > +{
> > +	rc = pci_get_msi_cap(adapter->pdev);
> > +	if (rc < 0)
> > +		return rc;
> > +
> > +	nvec = min(nvec, rc);
> > +	if (nvec < FOO_DRIVER_MINIMUM_NVEC) {
> > +		return -ENOSPC;
> > +
> > +	rc = pci_enable_msi_block(adapter->pdev, nvec);
> > +	return rc;
> > +}
> 
> If there are many which duplicate the above pattern, it'd probably be
> worthwhile to provide a helper?  It's usually a good idea to reduce
> the amount of boilerplate code in drivers.

I wanted to limit discussion in v1 to as little changes as possible.
I 'planned' those helper(s) for a separate effort if/when the most
important change is accepted and soaked a bit.

> > @@ -975,7 +951,7 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
> >  	if (nr_entries < 0)
> >  		return nr_entries;
> >  	if (nvec > nr_entries)
> > -		return nr_entries;
> > +		return -EINVAL;
> >  
> >  	/* Check for any invalid entries */
> >  	for (i = 0; i < nvec; i++) {
> 
> If we do things this way, it breaks all drivers using this interface
> until they're converted, right?

Right. And the rest of the series does it.

> Also, it probably isn't the best idea
> to flip the behavior like this as this can go completely unnoticed (no
> compiler warning or anything, the same function just behaves
> differently).  Maybe it'd be a better idea to introduce a simpler
> interface that most can be converted to?

Well, an *other* interface is a good idea. What do you mean with the
simpler here?

> tejun

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 07/77] PCI/MSI: Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello, Alexander.

On Tue, Oct 08, 2013 at 09:48:26AM +0200, Alexander Gordeev wrote:
> > If there are many which duplicate the above pattern, it'd probably be
> > worthwhile to provide a helper?  It's usually a good idea to reduce
> > the amount of boilerplate code in drivers.
> 
> I wanted to limit discussion in v1 to as little changes as possible.
> I 'planned' those helper(s) for a separate effort if/when the most
> important change is accepted and soaked a bit.

The thing is doing it this way generates more churns and noises.  Once
the simpler ones live behind a wrapper which can be built on the
existing interface, we can have both reduced cost and more latitude on
the complex cases.

> > If we do things this way, it breaks all drivers using this interface
> > until they're converted, right?
> 
> Right. And the rest of the series does it.

Which breaks bisection which we shouldn't do.

> > Also, it probably isn't the best idea
> > to flip the behavior like this as this can go completely unnoticed (no
> > compiler warning or anything, the same function just behaves
> > differently).  Maybe it'd be a better idea to introduce a simpler
> > interface that most can be converted to?
> 
> Well, an *other* interface is a good idea. What do you mean with the
> simpler here?

I'm still talking about a simpler wrapper for common cases, which is
the important part anyway.

Thanks.

-- 
tejun

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello, Alexander.

On Wed, Oct 02, 2013 at 12:48:16PM +0200, Alexander Gordeev wrote:
> Alexander Gordeev (77):
>   PCI/MSI: Fix return value when populate_msi_sysfs() failed
>   PCI/MSI/PPC: Fix wrong RTAS error code reporting
>   PCI/MSI/s390: Fix single MSI only check
>   PCI/MSI/s390: Remove superfluous check of MSI type
>   PCI/MSI: Convert pci_msix_table_size() to a public interface
>   PCI/MSI: Factor out pci_get_msi_cap() interface
>   PCI/MSI: Re-design MSI/MSI-X interrupts enablement pattern
>   PCI/MSI: Get rid of pci_enable_msi_block_auto() interface
>   ahci: Update MSI/MSI-X interrupts enablement code
>   ahci: Check MRSM bit when multiple MSIs enabled
...

Whee.... that's a lot more than I expected.  I was just scanning
multiple msi users.  Maybe we can stage the work in more manageable
steps so that you don't have to go through massive conversion only to
do it all over again afterwards and likewise people don't get
bombarded on each iteration?  Maybe we can first update pci / msi code
proper, msi and then msix?

Thanks.

-- 
tejun

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Mon, Oct 07, 2013 at 02:21:17PM -0400, Tejun Heo wrote:
> Whee.... that's a lot more than I expected.  I was just scanning
> multiple msi users.  Maybe we can stage the work in more manageable
> steps so that you don't have to go through massive conversion only to
> do it all over again afterwards and likewise people don't get
> bombarded on each iteration?  Maybe we can first update pci / msi code
> proper, msi and then msix?

Multipe MSIs is just a handful of drivers, really. MSI-X impact still
will be huge. But if we opt a different name for the new pci_enable_msix()
then we could first update pci/msi, then drivers (in few stages possibly)
and finally remove the old implementation.

> tejun

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Tejun Heo]

Hello,

On Tue, Oct 08, 2013 at 11:07:16AM +0200, Alexander Gordeev wrote:
> Multipe MSIs is just a handful of drivers, really. MSI-X impact still

Yes, so it's pretty nice to try out things there before going full-on.

> will be huge. But if we opt a different name for the new pci_enable_msix()
> then we could first update pci/msi, then drivers (in few stages possibly)
> and finally remove the old implementation.

Yes, that probably should be the steps to follow eventually.  My point
was that you don't have to submit patches for all 7x conversions for
an RFC round.  Scanning them and seeing what would be necessary
definitely is a good idea but just giving summary of the full
conversion with several examples should be good enough before settling
on the way forward, which should be easier for all involved.

Thanks a lot for your effort!

-- 
tejun

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Michael Ellerman]

On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> This series is against "next" branch in Bjorn's repo:
> git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git
> 
> Currently pci_enable_msi_block() and pci_enable_msix() interfaces
> return a error code in case of failure, 0 in case of success and a
> positive value which indicates the number of MSI-X/MSI interrupts
> that could have been allocated. The latter value should be passed
> to a repeated call to the interfaces until a failure or success:
> 
> 
> 	for (i = 0; i < FOO_DRIVER_MAXIMUM_NVEC; i++)
> 		adapter->msix_entries[i].entry = i;
> 
> 	while (nvec >= FOO_DRIVER_MINIMUM_NVEC) {
> 		rc = pci_enable_msix(adapter->pdev,
> 				     adapter->msix_entries, nvec);
> 		if (rc > 0)
> 			nvec = rc;
> 		else
> 			return rc;
> 	}
> 
> 	return -ENOSPC;
> 
> 
> This technique proved to be confusing and error-prone. Vast share
> of device drivers simply fail to follow the described guidelines.

To clarify "Vast share of device drivers":

 - 58 drivers call pci_enable_msix()
 - 24 try a single allocation and then fallback to MSI/LSI
 - 19 use the loop style allocation as above
 - 14 try an allocation, and if it fails retry once
 - 1  incorrectly continues when pci_enable_msix() returns > 0

So 33 drivers (> 50%) successfully make use of the "confusing and
error-prone" return value.

Another 24 happily ignore it, which is also entirely fine.

And yes, one is buggy, so obviously the interface is too complex. Thanks
drivers/ntb/ntb_hw.c

cheers

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote:
> On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> > This technique proved to be confusing and error-prone. Vast share
> > of device drivers simply fail to follow the described guidelines.
> 
> To clarify "Vast share of device drivers":
> 
>  - 58 drivers call pci_enable_msix()
>  - 24 try a single allocation and then fallback to MSI/LSI
>  - 19 use the loop style allocation as above
>  - 14 try an allocation, and if it fails retry once
>  - 1  incorrectly continues when pci_enable_msix() returns > 0
> 
> So 33 drivers (> 50%) successfully make use of the "confusing and
> error-prone" return value.

Ok, you caught me - 'vast share' is incorrect and is a subject to
rewording. But out of 19/58 how many drivers tested fallbacks on the
real hardware? IOW, which drivers are affected by the pSeries quota?

> And yes, one is buggy, so obviously the interface is too complex. Thanks
> drivers/ntb/ntb_hw.c

vmxnet3 would be the best example.

> cheers

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Michael Ellerman]

On Tue, Oct 08, 2013 at 09:33:02AM +0200, Alexander Gordeev wrote:
> On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote:
> > On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> > > This technique proved to be confusing and error-prone. Vast share
> > > of device drivers simply fail to follow the described guidelines.
> > 
> > To clarify "Vast share of device drivers":
> > 
> >  - 58 drivers call pci_enable_msix()
> >  - 24 try a single allocation and then fallback to MSI/LSI
> >  - 19 use the loop style allocation as above
> >  - 14 try an allocation, and if it fails retry once
> >  - 1  incorrectly continues when pci_enable_msix() returns > 0
> > 
> > So 33 drivers (> 50%) successfully make use of the "confusing and
> > error-prone" return value.
> 
> Ok, you caught me - 'vast share' is incorrect and is a subject to
> rewording. But out of 19/58 how many drivers tested fallbacks on the
> real hardware? IOW, which drivers are affected by the pSeries quota?

It's not 19/58, it's 33/58.

As to how many we care about on powerpc I can't say, so you have a point
there. But I still think the interface is not actually that terrible.

cheers

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Mark Lord]

On 13-10-02 06:29 AM, Alexander Gordeev wrote:
..
> This update converts pci_enable_msix() and pci_enable_msi_block()
> interfaces to canonical kernel functions and makes them return a
> error code in case of failure or 0 in case of success.

Rather than silently break dozens of drivers in mysterious ways,
please invent new function names for the replacements to the
existing pci_enable_msix() and pci_enable_msi_block() functions.

That way, both in-tree and out-of-tree drivers will notice the API change,
rather than having it go unseen and just failing for unknown reasons.

Thanks.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[H. Peter Anvin]

On 10/02/2013 03:29 AM, Alexander Gordeev wrote:
> 
> As result, device drivers will cease to use the overcomplicated
> repeated fallbacks technique and resort to a straightforward
> pattern - determine the number of MSI/MSI-X interrupts required
> before calling pci_enable_msi_block() and pci_enable_msix()
> interfaces:
> 
> 
> 	rc = pci_msix_table_size(adapter->pdev);
> 	if (rc < 0)
> 		return rc;
> 
> 	nvec = min(nvec, rc);
> 	if (nvec < FOO_DRIVER_MINIMUM_NVEC) {
> 		return -ENOSPC;
> 
> 	for (i = 0; i < nvec; i++)
> 		adapter->msix_entries[i].entry = i;
> 
> 	rc = pci_enable_msix(adapter->pdev,
> 			     adapter->msix_entries, nvec);
> 	return rc;
> 

Why not add a minimum number to pci_enable_msix(), i.e.:

pci_enable_msix(pdev, msix_entries, nvec, minvec)

... which means "nvec" is the number of interrupts *requested*, and
"minvec" is the minimum acceptable number (otherwise fail).

	-hpa

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Benjamin Herrenschmidt]

On Tue, 2013-10-08 at 20:55 -0700, H. Peter Anvin wrote:
> Why not add a minimum number to pci_enable_msix(), i.e.:
> 
> pci_enable_msix(pdev, msix_entries, nvec, minvec)
> 
> ... which means "nvec" is the number of interrupts *requested*, and
> "minvec" is the minimum acceptable number (otherwise fail).

Which is exactly what Ben (the other Ben :-) suggested and that I
supports...

Cheers,
Ben.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2013-10-08 at 20:55 -0700, H. Peter Anvin wrote:
> > Why not add a minimum number to pci_enable_msix(), i.e.:
> > 
> > pci_enable_msix(pdev, msix_entries, nvec, minvec)
> > 
> > ... which means "nvec" is the number of interrupts *requested*, and
> > "minvec" is the minimum acceptable number (otherwise fail).
> 
> Which is exactly what Ben (the other Ben :-) suggested and that I
> supports...

Ok, this suggestion sounded in one or another form by several people.
What about name it pcim_enable_msix_range() and wrap in couple more
helpers to complete an API:

int pcim_enable_msix_range(pdev, msix_entries, nvec, minvec);
	<0 - error code
	>0 - number of MSIs allocated, where minvec >= result <= nvec

int pcim_enable_msix(pdev, msix_entries, nvec);
	<0 - error code
	>0 - number of MSIs allocated, where 1 >= result <= nvec 

int pcim_enable_msix_exact(pdev, msix_entries, nvec);
	<0 - error code
	>0 - number of MSIs allocated, where result == nvec

The latter's return value seems odd, but I can not help to make
it consistent with the first two.


(Sorry if you see this message twice - my MUA seems struggle with one of CC).

> Cheers,
> Ben.
> 
> 

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[H. Peter Anvin]

On 10/10/2013 03:17 AM, Alexander Gordeev wrote:
> On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
> 
> Ok, this suggestion sounded in one or another form by several people.
> What about name it pcim_enable_msix_range() and wrap in couple more
> helpers to complete an API:
> 
> int pcim_enable_msix_range(pdev, msix_entries, nvec, minvec);
> 	<0 - error code
> 	>0 - number of MSIs allocated, where minvec >= result <= nvec
> 
> int pcim_enable_msix(pdev, msix_entries, nvec);
> 	<0 - error code
> 	>0 - number of MSIs allocated, where 1 >= result <= nvec 
> 
> int pcim_enable_msix_exact(pdev, msix_entries, nvec);
> 	<0 - error code
> 	>0 - number of MSIs allocated, where result == nvec
> 
> The latter's return value seems odd, but I can not help to make
> it consistent with the first two.
> 

Is there a reason for the wrappers, as opposed to just specifying either
1 or nvec as the minimum?

	-hpa

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Thu, Oct 10, 2013 at 09:28:27AM -0700, H. Peter Anvin wrote:
> On 10/10/2013 03:17 AM, Alexander Gordeev wrote:
> > On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
> > 
> > Ok, this suggestion sounded in one or another form by several people.
> > What about name it pcim_enable_msix_range() and wrap in couple more
> > helpers to complete an API:
> > 
> > int pcim_enable_msix_range(pdev, msix_entries, nvec, minvec);
> > 	<0 - error code
> > 	>0 - number of MSIs allocated, where minvec >= result <= nvec
> > 
> > int pcim_enable_msix(pdev, msix_entries, nvec);
> > 	<0 - error code
> > 	>0 - number of MSIs allocated, where 1 >= result <= nvec 
> > 
> > int pcim_enable_msix_exact(pdev, msix_entries, nvec);
> > 	<0 - error code
> > 	>0 - number of MSIs allocated, where result == nvec
> > 
> > The latter's return value seems odd, but I can not help to make
> > it consistent with the first two.
> > 
> 
> Is there a reason for the wrappers, as opposed to just specifying either
> 1 or nvec as the minimum?

The wrappers are more handy IMO.

I.e. can imagine people start struggling to figure out what minvec to provide:
1 or 0? Why 1? Oh.. okay.. Or should we tolerate 0 (as opposite to -ERANGE)?

Well, do not know.. pcim_enable_msix(pdev, msix_entries, nvec, nvec) is 
less readable for me than just pcim_enable_msix_exact(pdev, msix_entries,
nvec).

> 	-hpa

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Mark Lord]

Just to help us all understand "the loop" issue..

Here's an example of driver code which uses the existing MSI-X interfaces,
for a device which can work with either 16, 8, 4, 2, or 1 MSI-X interrupt.
This is from a new driver I'm working on right now:


static int xx_alloc_msix_irqs (struct xx_dev *dev, int nvec)
{
        xx_disable_all_irqs(dev);
        do {
                if (nvec < 2)
                        xx_prep_for_1_msix_vector(dev);
                else if (nvec < 4)
                        xx_prep_for_2_msix_vectors(dev);
                else if (nvec < 8)
                        xx_prep_for_4_msix_vectors(dev);
                else if (nvec < 16)
                        xx_prep_for_8_msix_vectors(dev);
                else
                        xx_prep_for_16_msix_vectors(dev);
                nvec = pci_enable_msix(dev->pdev, dev->irqs, dev->num_vectors);
        } while (nvec > 0);

        if (nvec) {
                kerr(dev->name, "pci_enable_msix() failed, err=%d", nvec);
                dev->num_vectors = 0;
                return nvec;
        }
        return 0;       /* success */
}

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Thu, Oct 10, 2013 at 07:17:18PM -0400, Mark Lord wrote:
> Just to help us all understand "the loop" issue..
> 
> Here's an example of driver code which uses the existing MSI-X interfaces,
> for a device which can work with either 16, 8, 4, 2, or 1 MSI-X interrupt.
> This is from a new driver I'm working on right now:
> 
> 
> static int xx_alloc_msix_irqs (struct xx_dev *dev, int nvec)
> {
>         xx_disable_all_irqs(dev);
>         do {
>                 if (nvec < 2)
>                         xx_prep_for_1_msix_vector(dev);
>                 else if (nvec < 4)
>                         xx_prep_for_2_msix_vectors(dev);
>                 else if (nvec < 8)
>                         xx_prep_for_4_msix_vectors(dev);
>                 else if (nvec < 16)
>                         xx_prep_for_8_msix_vectors(dev);
>                 else
>                         xx_prep_for_16_msix_vectors(dev);
>                 nvec = pci_enable_msix(dev->pdev, dev->irqs, dev->num_vectors);
>         } while (nvec > 0);
> 
>         if (nvec) {
>                 kerr(dev->name, "pci_enable_msix() failed, err=%d", nvec);
>                 dev->num_vectors = 0;
>                 return nvec;
>         }
>         return 0;       /* success */
> }

Yeah, that is a very good example.

I would move all xx_prep_for_<pow2>_msix_vector() functions to a single
helper i.e. xx_prep_msix_vectors(dev, ndev).

Considering also (a) we do not want to waste unused platform resources
associated with MSI-Xs and pull more quota than needed and (b) fixing
couple of bugs, this function could look like this:

static int xx_alloc_msix_irqs(struct xx_dev *dev, int nvec_in)
{
	int nvec = roundup_pow_of_two(nvec_in);	/* assume 0 > nvec_in <= 16 */
	int rc;

	xx_disable_all_irqs(dev);

retry:
       	xx_prep_for_msix_vectors(dev, nvec);

	rc = pci_enable_msix(dev->pdev, dev->irqs, nvec);	/* (b) */
	if (rc > 0) {
		nvec = rounddown_pow_of_two(nvec);		/* (a) */
		goto retry;
	}

	if (rc) {
		kerr(dev->name, "pci_enable_msix() failed, err=%d", rc);
		dev->num_vectors = 0;
		return rc;
	}

	dev->num_vectors = nvec;				/* (b) */
	return 0;       /* success */
}

Now, this is a loop-free alternative:

static int xx_alloc_msix_irqs(struct xx_dev *dev, int nvec)
{
	nvec = roundup_pow_of_two(nvec);	/* assume 0 > nvec <= 16 */

	xx_disable_all_irqs(dev);

	pci_lock_msi(dev->pdev);

	rc = pci_get_msix_limit(dev->pdev, nvec);
	if (rc < 0)
		goto err;

	nvec = min(nvec, rc);		/* if limit is more than requested */
	nvec = rounddown_pow_of_two(nvec);	/* (a) */

	xx_prep_for_msix_vectors(dev, nvec);

	rc = pci_enable_msix(dev->pdev, dev->irqs, nvec);	/* (b)	*/
	if (rc < 0)
		goto err;

	pci_unlock_msi(dev->pdev);

	dev->num_vectors = nvec;		/* (b) */
	return 0;

err:
	pci_unlock_msi(dev->pdev);

        kerr(dev->name, "pci_enable_msix() failed, err=%d", rc);
        dev->num_vectors = 0;
        return rc;
}

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Mark Lord]

On 13-10-11 04:41 AM, Alexander Gordeev wrote:
> On Thu, Oct 10, 2013 at 07:17:18PM -0400, Mark Lord wrote:
>> Just to help us all understand "the loop" issue..
>>
>> Here's an example of driver code which uses the existing MSI-X interfaces,
>> for a device which can work with either 16, 8, 4, 2, or 1 MSI-X interrupt.
>> This is from a new driver I'm working on right now:
..
> Now, this is a loop-free alternative:
> 
> static int xx_alloc_msix_irqs(struct xx_dev *dev, int nvec)
> {
> 	nvec = roundup_pow_of_two(nvec);	/* assume 0 > nvec <= 16 */
> 
> 	xx_disable_all_irqs(dev);
> 
> 	pci_lock_msi(dev->pdev);
> 
> 	rc = pci_get_msix_limit(dev->pdev, nvec);
> 	if (rc < 0)
> 		goto err;
> 
> 	nvec = min(nvec, rc);		/* if limit is more than requested */
> 	nvec = rounddown_pow_of_two(nvec);	/* (a) */
> 
> 	xx_prep_for_msix_vectors(dev, nvec);
> 
> 	rc = pci_enable_msix(dev->pdev, dev->irqs, nvec);	/* (b)	*/
> 	if (rc < 0)
> 		goto err;
> 
> 	pci_unlock_msi(dev->pdev);
> 
> 	dev->num_vectors = nvec;		/* (b) */
> 	return 0;
> 
> err:
> 	pci_unlock_msi(dev->pdev);
> 
>         kerr(dev->name, "pci_enable_msix() failed, err=%d", rc);
>         dev->num_vectors = 0;
>         return rc;
> }

That would still need a loop, to handle the natural race between
the calls to pci_get_msix_limit() and pci_enable_msix() -- the driver and device
can and should fall back to a smaller number of vectors when pci_enable_msix() fails.

Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

[Alexander Gordeev]

On Fri, Oct 11, 2013 at 04:29:39PM -0400, Mark Lord wrote:
> > static int xx_alloc_msix_irqs(struct xx_dev *dev, int nvec)
> > {
> > 	nvec = roundup_pow_of_two(nvec);	/* assume 0 > nvec <= 16 */
> > 
> > 	xx_disable_all_irqs(dev);
> > 
> > 	pci_lock_msi(dev->pdev);
> > 
> > 	rc = pci_get_msix_limit(dev->pdev, nvec);
> > 	if (rc < 0)
> > 		goto err;
> > 
> > 	nvec = min(nvec, rc);		/* if limit is more than requested */
> > 	nvec = rounddown_pow_of_two(nvec);	/* (a) */
> > 
> > 	xx_prep_for_msix_vectors(dev, nvec);
> > 
> > 	rc = pci_enable_msix(dev->pdev, dev->irqs, nvec);	/* (b)	*/
> > 	if (rc < 0)
> > 		goto err;
> > 
> > 	pci_unlock_msi(dev->pdev);
> > 
> > 	dev->num_vectors = nvec;		/* (b) */
> > 	return 0;
> > 
> > err:
> > 	pci_unlock_msi(dev->pdev);
> > 
> >         kerr(dev->name, "pci_enable_msix() failed, err=%d", rc);
> >         dev->num_vectors = 0;
> >         return rc;
> > }
> 
> That would still need a loop, to handle the natural race between
> the calls to pci_get_msix_limit() and pci_enable_msix() -- the driver and device
> can and should fall back to a smaller number of vectors when pci_enable_msix() fails.

Could you please explain why the value returned by pci_get_msix_limit()
might change before pci_enable_msix() returned, while both protected by
pci_lock_msi()?

Anyway, although the loop-free code (IMHO) reads better, pci_lock_msi()
it is not a part of the original proposal and the more I think about it
the less I like it.

-- 
Regards,
Alexander Gordeev
agordeev@redhat.com