* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Wolfram Sang @ 2020-09-10 6:53 UTC (permalink / raw)
To: Joe Perches
Cc: linux-wireless, linux-fbdev, oss-drivers, nouveau, alsa-devel,
dri-devel, linux-mips, linux-ide, dm-devel, linux-mtd, linux-i2c,
sparclinux, kvmarm, linux-rtc, linux-s390, linux-scsi, dccp,
linux-rdma, linux-atm-general, linux-afs, coreteam,
intel-wired-lan, linux-serial, linux-input, linux-mmc, Kees Cook,
linux-media, linux-pm, intel-gfx, linux-sctp, linux-mediatek,
linux-nvme, storagedev, ceph-devel, linux-arm-kernel, linux-nfs,
Jiri Kosina, linux-parisc, netdev, linux-usb, Nick Desaulniers,
LKML, iommu, netfilter-devel, linux-crypto, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
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> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index e32ef3f01fe8..b13b1cbcac29 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1785,7 +1785,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
> fallthrough;
> case PCI_DEVICE_ID_INTEL_82801CA_3:
> priv->features |= FEATURE_HOST_NOTIFY;
> - fallthrough;
> + break;
> case PCI_DEVICE_ID_INTEL_82801BA_2:
> case PCI_DEVICE_ID_INTEL_82801AB_3:
> case PCI_DEVICE_ID_INTEL_82801AA_3:
I am not the maintainer (Jean is) but I suggest to drop this hunk. The
code is more complex with multiple 'fallthrough', so this change alone
actually makes the code inconsistent. A rework would need a seperate
patch.
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^ permalink raw reply
* Re: [PATCH] powerpc/pseries: explicitly reschedule during drmem_lmb list traversal
From: Michael Ellerman @ 2020-09-10 7:37 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev, Nathan Lynch; +Cc: tyreld, cheloha, ldufour
In-Reply-To: <159965716536.808686.6770489962945335382.b4-ty@ellerman.id.au>
Michael Ellerman <patch-notifications@ellerman.id.au> writes:
> On Tue, 28 Jul 2020 12:37:41 -0500, Nathan Lynch wrote:
>> The drmem lmb list can have hundreds of thousands of entries, and
>> unfortunately lookups take the form of linear searches. As long as
>> this is the case, traversals have the potential to monopolize the CPU
>> and provoke lockup reports, workqueue stalls, and the like unless
>> they explicitly yield.
>>
>> Rather than placing cond_resched() calls within various
>> for_each_drmem_lmb() loop blocks in the code, put it in the iteration
>> expression of the loop macro itself so users can't omit it.
>
> Applied to powerpc/next.
>
> [1/1] powerpc/pseries: explicitly reschedule during drmem_lmb list traversal
> https://git.kernel.org/powerpc/c/9d6792ffe140240ae54c881cc4183f9acc24b4df
Some script gremlins here, I actually applied v3 (only once).
cheers
^ permalink raw reply
* Re: [PATCH v2] powerpc: Warn about use of smt_snooze_delay
From: Michael Ellerman @ 2020-09-10 7:39 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev, Joel Stanley
Cc: Gautham R Shenoy, Tyrel Datwyler
In-Reply-To: <159965716554.808686.4840855488904790852.b4-ty@ellerman.id.au>
Michael Ellerman <patch-notifications@ellerman.id.au> writes:
> On Tue, 30 Jun 2020 11:29:35 +0930, Joel Stanley wrote:
>> It's not done anything for a long time. Save the percpu variable, and
>> emit a warning to remind users to not expect it to do anything.
>>
>> Fixes: 3fa8cad82b94 ("powerpc/pseries/cpuidle: smt-snooze-delay cleanup.")
>> Cc: stable@vger.kernel.org # v3.14
>> Signed-off-by: Joel Stanley <joel@jms.id.au>
>> --
>> v2:
>> Use pr_warn instead of WARN
>> Reword and print proccess name with pid in message
>> Leave CPU_FTR_SMT test in
>> Add Fixes line
>>
>> [...]
>
> Applied to powerpc/next.
>
> [1/1] powerpc: Warn about use of smt_snooze_delay
> https://git.kernel.org/powerpc/c/a02f6d42357acf6e5de6ffc728e6e77faf3ad217
I applied v3 actually.
cheers
^ permalink raw reply
* RE: remove the last set_fs() in common code, and remove it for x86 and powerpc v3
From: David Laight @ 2020-09-10 8:04 UTC (permalink / raw)
To: 'Linus Torvalds', Segher Boessenkool
Cc: linux-arch, Kees Cook, the arch/x86 maintainers, Nick Desaulniers,
Linux Kernel Mailing List, Christoph Hellwig, Luis Chamberlain,
Al Viro, linux-fsdevel, linuxppc-dev, Alexey Dobriyan
In-Reply-To: <CAHk-=whu19Du_rZ-zBtGsXAB-Qo7NtoJjQjd-Sa9OB5u1Cq_Zw@mail.gmail.com>
From: Linus Torvalds
> Sent: 09 September 2020 22:34
> On Wed, Sep 9, 2020 at 11:42 AM Segher Boessenkool
> <segher@kernel.crashing.org> wrote:
> >
> > It will not work like this in GCC, no. The LLVM people know about that.
> > I do not know why they insist on pushing this, being incompatible and
> > everything.
>
> Umm. Since they'd be the ones supporting this, *gcc* would be the
> incompatible one, not clang.
I had an 'interesting' idea.
Can you use a local asm register variable as an input and output to
an 'asm volatile goto' statement?
Well you can - but is it guaranteed to work :-)
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply
* Re: remove the last set_fs() in common code, and remove it for x86 and powerpc v3
From: Christophe Leroy @ 2020-09-10 8:13 UTC (permalink / raw)
To: David Laight, 'Linus Torvalds', Segher Boessenkool
Cc: linux-arch, Kees Cook, the arch/x86 maintainers, Nick Desaulniers,
Linux Kernel Mailing List, Alexey Dobriyan, Luis Chamberlain,
Al Viro, linux-fsdevel, linuxppc-dev, Christoph Hellwig
In-Reply-To: <3beb8b019e4a4f7b81fdb1bc68bd1e2d@AcuMS.aculab.com>
Le 10/09/2020 à 10:04, David Laight a écrit :
> From: Linus Torvalds
>> Sent: 09 September 2020 22:34
>> On Wed, Sep 9, 2020 at 11:42 AM Segher Boessenkool
>> <segher@kernel.crashing.org> wrote:
>>>
>>> It will not work like this in GCC, no. The LLVM people know about that.
>>> I do not know why they insist on pushing this, being incompatible and
>>> everything.
>>
>> Umm. Since they'd be the ones supporting this, *gcc* would be the
>> incompatible one, not clang.
>
> I had an 'interesting' idea.
>
> Can you use a local asm register variable as an input and output to
> an 'asm volatile goto' statement?
>
> Well you can - but is it guaranteed to work :-)
>
With gcc at least it should work according to
https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
They even explicitely tell: "The only supported use for this feature is
to specify registers for input and output operands when calling Extended
asm "
Christophe
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Nicolas.Ferre @ 2020-09-10 8:24 UTC (permalink / raw)
To: joe, linux-kernel, trivial
Cc: linux-wireless, linux-fbdev, oss-drivers, nouveau, alsa-devel,
dri-devel, linux-ide, dm-devel, linux-mtd, linux-i2c, sparclinux,
kvmarm, linux-rtc, linux-s390, linux-scsi, dccp, linux-rdma,
linux-atm-general, linux-afs, Ludovic.Desroches, coreteam,
intel-wired-lan, linux-serial, linux-input, linux-mmc, kees.cook,
linux-media, linux-pm, intel-gfx, linux-sctp, linux-mediatek,
linux-nvme, storagedev, ceph-devel, linux-arm-kernel, linux-nfs,
linux-parisc, netdev, linux-usb, ndesaulniers, linux-mips, iommu,
netfilter-devel, linux-crypto, Eugen.Hristev, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
Joe,
Please drop this chunk: it's a successive controller version number
which are all backward compatible with "fallthrough" on each case so
removing from this last one makes it inconsistent.
In sort: NACK for atmel-mci.
Best regards,
Nicolas
On 09/09/2020 at 22:06, Joe Perches wrote:
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index 444bd3a0a922..8324312e4f42 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -2435,7 +2435,7 @@ static void atmci_get_cap(struct atmel_mci *host)
> case 0x100:
> host->caps.has_bad_data_ordering = 0;
> host->caps.need_reset_after_xfer = 0;
> - fallthrough;
> + break;
> case 0x0:
> break;
> default:
--
Nicolas Ferre
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Felipe Balbi @ 2020-09-10 8:47 UTC (permalink / raw)
To: Joe Perches, LKML, Jiri Kosina
Cc: linux-wireless, linux-fbdev, oss-drivers, nouveau, alsa-devel,
dri-devel, linux-ide, dm-devel, linux-mtd, linux-i2c, sparclinux,
kvmarm, linux-rtc, linux-s390, linux-scsi, dccp, linux-rdma,
linux-atm-general, linux-afs, coreteam, intel-wired-lan,
linux-serial, linux-input, linux-mmc, Kees Cook, linux-media,
linux-pm, intel-gfx, linux-sctp, linux-mediatek, linux-nvme,
storagedev, ceph-devel, linux-arm-kernel, linux-nfs, linux-parisc,
netdev, linux-usb, Nick Desaulniers, linux-mips, iommu,
netfilter-devel, linux-crypto, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
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Hi,
Joe Perches <joe@perches.com> writes:
> drivers/usb/dwc3/core.c | 2 +-
> drivers/usb/gadget/legacy/inode.c | 2 +-
> drivers/usb/gadget/udc/pxa25x_udc.c | 4 ++--
> drivers/usb/phy/phy-fsl-usb.c | 2 +-
for the drivers above:
Acked-by: Felipe Balbi <balbi@kernel.org>
--
balbi
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^ permalink raw reply
* [PATCH v3 3/7] mm/memory_hotplug: prepare passing flags to add_memory() and friends
From: David Hildenbrand @ 2020-09-10 9:13 UTC (permalink / raw)
To: linux-kernel
Cc: linux-hyperv, Michal Hocko, David Hildenbrand, Jason Wang,
Pingfan Liu, virtualization, linux-mm, Paul Mackerras,
K. Y. Srinivasan, Boris Ostrovsky, linux-s390, Wei Liu,
Stefano Stabellini, Dave Jiang, Baoquan He, linux-nvdimm,
Jason Gunthorpe, Michael S. Tsirkin, linux-acpi, xen-devel,
Heiko Carstens, Len Brown, Nathan Lynch, Vasily Gorbik,
Leonardo Bras, Haiyang Zhang, Stephen Hemminger, Dan Williams,
Christian Borntraeger, Juergen Gross, Pankaj Gupta,
Libor Pechacek, Greg Kroah-Hartman, Rafael J. Wysocki, Wei Yang,
Vishal Verma, Oliver O'Halloran, Andrew Morton, linuxppc-dev
In-Reply-To: <20200910091340.8654-1-david@redhat.com>
We soon want to pass flags, e.g., to mark added System RAM resources.
mergeable. Prepare for that.
This patch is based on a similar patch by Oscar Salvador:
https://lkml.kernel.org/r/20190625075227.15193-3-osalvador@suse.de
Acked-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com> # Xen related part
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Leonardo Bras <leobras.c@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: linux-hyperv@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 2 +-
arch/powerpc/platforms/pseries/hotplug-memory.c | 2 +-
drivers/acpi/acpi_memhotplug.c | 3 ++-
drivers/base/memory.c | 3 ++-
drivers/dax/kmem.c | 2 +-
drivers/hv/hv_balloon.c | 2 +-
drivers/s390/char/sclp_cmd.c | 2 +-
drivers/virtio/virtio_mem.c | 2 +-
drivers/xen/balloon.c | 2 +-
include/linux/memory_hotplug.h | 16 ++++++++++++----
mm/memory_hotplug.c | 14 +++++++-------
11 files changed, 30 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 13b369d2cc454..6828108486f83 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -224,7 +224,7 @@ static int memtrace_online(void)
ent->mem = 0;
}
- if (add_memory(ent->nid, ent->start, ent->size)) {
+ if (add_memory(ent->nid, ent->start, ent->size, MHP_NONE)) {
pr_err("Failed to add trace memory to node %d\n",
ent->nid);
ret += 1;
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 0ea976d1cac47..e1c9fa0d730f5 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -615,7 +615,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
nid = memory_add_physaddr_to_nid(lmb->base_addr);
/* Add the memory */
- rc = __add_memory(nid, lmb->base_addr, block_sz);
+ rc = __add_memory(nid, lmb->base_addr, block_sz, MHP_NONE);
if (rc) {
invalidate_lmb_associativity_index(lmb);
return rc;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index e294f44a78504..2067c3bc55763 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -207,7 +207,8 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);
- result = __add_memory(node, info->start_addr, info->length);
+ result = __add_memory(node, info->start_addr, info->length,
+ MHP_NONE);
/*
* If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 4db3c660de831..b4c297dd04755 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -432,7 +432,8 @@ static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
nid = memory_add_physaddr_to_nid(phys_addr);
ret = __add_memory(nid, phys_addr,
- MIN_MEMORY_BLOCK_SIZE * sections_per_block);
+ MIN_MEMORY_BLOCK_SIZE * sections_per_block,
+ MHP_NONE);
if (ret)
goto out;
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 7dcb2902e9b1b..896cb9444e727 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -95,7 +95,7 @@ int dev_dax_kmem_probe(struct dev_dax *dev_dax)
* this as RAM automatically.
*/
rc = add_memory_driver_managed(numa_node, range.start,
- range_len(&range), kmem_name);
+ range_len(&range), kmem_name, MHP_NONE);
res->flags |= IORESOURCE_BUSY;
if (rc) {
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 32e3bc0aa665a..3c0d52e244520 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -726,7 +726,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
ret = add_memory(nid, PFN_PHYS((start_pfn)),
- (HA_CHUNK << PAGE_SHIFT));
+ (HA_CHUNK << PAGE_SHIFT), MHP_NONE);
if (ret) {
pr_err("hot_add memory failed error is %d\n", ret);
diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index a864b21af602a..f6e97f0830f64 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -406,7 +406,7 @@ static void __init add_memory_merged(u16 rn)
if (!size)
goto skip_add;
for (addr = start; addr < start + size; addr += block_size)
- add_memory(0, addr, block_size);
+ add_memory(0, addr, block_size, MHP_NONE);
skip_add:
first_rn = rn;
num = 1;
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 834b7c13ef3dc..ed99e43354010 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -424,7 +424,7 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id)
dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id);
return add_memory_driver_managed(nid, addr, memory_block_size_bytes(),
- vm->resource_name);
+ vm->resource_name, MHP_NONE);
}
/*
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 51427c752b37b..9f40a294d398d 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -331,7 +331,7 @@ static enum bp_state reserve_additional_memory(void)
mutex_unlock(&balloon_mutex);
/* add_memory_resource() requires the device_hotplug lock */
lock_device_hotplug();
- rc = add_memory_resource(nid, resource);
+ rc = add_memory_resource(nid, resource, MHP_NONE);
unlock_device_hotplug();
mutex_lock(&balloon_mutex);
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 51a877fec8da8..e53d1058f3443 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -57,6 +57,12 @@ enum {
MMOP_ONLINE_MOVABLE,
};
+/* Flags for add_memory() and friends to specify memory hotplug details. */
+typedef int __bitwise mhp_t;
+
+/* No special request */
+#define MHP_NONE ((__force mhp_t)0)
+
/*
* Extended parameters for memory hotplug:
* altmap: alternative allocator for memmap array (optional)
@@ -345,11 +351,13 @@ extern void set_zone_contiguous(struct zone *zone);
extern void clear_zone_contiguous(struct zone *zone);
extern void __ref free_area_init_core_hotplug(int nid);
-extern int __add_memory(int nid, u64 start, u64 size);
-extern int add_memory(int nid, u64 start, u64 size);
-extern int add_memory_resource(int nid, struct resource *resource);
+extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
+extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
+extern int add_memory_resource(int nid, struct resource *resource,
+ mhp_t mhp_flags);
extern int add_memory_driver_managed(int nid, u64 start, u64 size,
- const char *resource_name);
+ const char *resource_name,
+ mhp_t mhp_flags);
extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages,
struct vmem_altmap *altmap, int migratetype);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8e1cd18b5cf14..8f0bd7c9a63a5 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1039,7 +1039,7 @@ static int online_memory_block(struct memory_block *mem, void *arg)
*
* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
*/
-int __ref add_memory_resource(int nid, struct resource *res)
+int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
{
struct mhp_params params = { .pgprot = PAGE_KERNEL };
u64 start, size;
@@ -1118,7 +1118,7 @@ int __ref add_memory_resource(int nid, struct resource *res)
}
/* requires device_hotplug_lock, see add_memory_resource() */
-int __ref __add_memory(int nid, u64 start, u64 size)
+int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
{
struct resource *res;
int ret;
@@ -1127,18 +1127,18 @@ int __ref __add_memory(int nid, u64 start, u64 size)
if (IS_ERR(res))
return PTR_ERR(res);
- ret = add_memory_resource(nid, res);
+ ret = add_memory_resource(nid, res, mhp_flags);
if (ret < 0)
release_memory_resource(res);
return ret;
}
-int add_memory(int nid, u64 start, u64 size)
+int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
{
int rc;
lock_device_hotplug();
- rc = __add_memory(nid, start, size);
+ rc = __add_memory(nid, start, size, mhp_flags);
unlock_device_hotplug();
return rc;
@@ -1167,7 +1167,7 @@ EXPORT_SYMBOL_GPL(add_memory);
* "System RAM ($DRIVER)".
*/
int add_memory_driver_managed(int nid, u64 start, u64 size,
- const char *resource_name)
+ const char *resource_name, mhp_t mhp_flags)
{
struct resource *res;
int rc;
@@ -1185,7 +1185,7 @@ int add_memory_driver_managed(int nid, u64 start, u64 size,
goto out_unlock;
}
- rc = add_memory_resource(nid, res);
+ rc = add_memory_resource(nid, res, mhp_flags);
if (rc < 0)
release_memory_resource(res);
--
2.26.2
^ permalink raw reply related
* [PATCH] powerpc/papr_scm: Fix warning triggered by perf_stats_show()
From: Vaibhav Jain @ 2020-09-10 9:22 UTC (permalink / raw)
To: linuxppc-dev, linux-nvdimm
Cc: Santosh Sivaraj, Oliver O'Halloran, Aneesh Kumar K . V,
Vaibhav Jain, Dan Williams, Ira Weiny
A warning is reported by the kernel in case perf_stats_show() returns
an error code. The warning is of the form below:
papr_scm ibm,persistent-memory:ibm,pmemory@44100001:
Failed to query performance stats, Err:-10
dev_attr_show: perf_stats_show+0x0/0x1c0 [papr_scm] returned bad count
fill_read_buffer: dev_attr_show+0x0/0xb0 returned bad count
On investigation it looks like that the compiler is silently truncating the
return value of drc_pmem_query_stats() from 'long' to 'int', since the
variable used to store the return code 'rc' is an 'int'. This
truncated value is then returned back as a 'ssize_t' back from
perf_stats_show() to 'dev_attr_show()' which thinks of it as a large
unsigned number and triggers this warning..
To fix this we update the type of variable 'rc' from 'int' to
'ssize_t' that prevents the compiler from truncating the return value
of drc_pmem_query_stats() and returning correct signed value back from
perf_stats_show().
Fixes: 2d02bf835e573 ('powerpc/papr_scm: Fetch nvdimm performance
stats from PHYP')
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
arch/powerpc/platforms/pseries/papr_scm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index a88a707a608aa..9f00b61676ab9 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -785,7 +785,8 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
static ssize_t perf_stats_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- int index, rc;
+ int index;
+ ssize_t rc;
struct seq_buf s;
struct papr_scm_perf_stat *stat;
struct papr_scm_perf_stats *stats;
--
2.26.2
^ permalink raw reply related
* RE: remove the last set_fs() in common code, and remove it for x86 and powerpc v3
From: David Laight @ 2020-09-10 9:26 UTC (permalink / raw)
To: 'Christophe Leroy', 'Linus Torvalds',
Segher Boessenkool
Cc: linux-arch, Kees Cook, the arch/x86 maintainers, Nick Desaulniers,
Linux Kernel Mailing List, Alexey Dobriyan, Luis Chamberlain,
Al Viro, linux-fsdevel, linuxppc-dev, Christoph Hellwig
In-Reply-To: <186a62fc-042c-d6ab-e7dc-e61b18945498@csgroup.eu>
From: Christophe Leroy
> Sent: 10 September 2020 09:14
>
> Le 10/09/2020 à 10:04, David Laight a écrit :
> > From: Linus Torvalds
> >> Sent: 09 September 2020 22:34
> >> On Wed, Sep 9, 2020 at 11:42 AM Segher Boessenkool
> >> <segher@kernel.crashing.org> wrote:
> >>>
> >>> It will not work like this in GCC, no. The LLVM people know about that.
> >>> I do not know why they insist on pushing this, being incompatible and
> >>> everything.
> >>
> >> Umm. Since they'd be the ones supporting this, *gcc* would be the
> >> incompatible one, not clang.
> >
> > I had an 'interesting' idea.
> >
> > Can you use a local asm register variable as an input and output to
> > an 'asm volatile goto' statement?
> >
> > Well you can - but is it guaranteed to work :-)
> >
>
> With gcc at least it should work according to
> https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
>
> They even explicitely tell: "The only supported use for this feature is
> to specify registers for input and output operands when calling Extended
> asm "
A quick test isn't good....
int bar(char *z)
{
__label__ label;
register int eax asm ("eax") = 6;
asm volatile goto (" mov $1, %%eax" ::: "eax" : label);
label:
return eax;
}
0000000000000040 <bar>:
40: b8 01 00 00 00 mov $0x1,%eax
45: b8 06 00 00 00 mov $0x6,%eax
4a: c3 retq
although adding:
asm volatile ("" : "+r" (eax));
either side of the 'asm volatile goto' does fix it.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply
* Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
From: Alexander Gordeev @ 2020-09-10 9:39 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: Peter Zijlstra, Dave Hansen, Dave Hansen, Paul Mackerras,
linux-sparc, Claudio Imbrenda, Will Deacon, linux-arch,
linux-s390, Vasily Gorbik, Richard Weinberger, linux-x86,
Russell King, Christian Borntraeger, Ingo Molnar, Catalin Marinas,
Andrey Ryabinin, Gerald Schaefer, Heiko Carstens, Arnd Bergmann,
John Hubbard, Jeff Dike, linux-um, Borislav Petkov,
Andy Lutomirski, Thomas Gleixner, linux-arm, linux-mm,
linux-power, LKML, Andrew Morton, Linus Torvalds, Mike Rapoport
In-Reply-To: <20200909180324.GI87483@ziepe.ca>
On Wed, Sep 09, 2020 at 03:03:24PM -0300, Jason Gunthorpe wrote:
> On Wed, Sep 09, 2020 at 07:25:34PM +0200, Gerald Schaefer wrote:
> > I actually had to draw myself a picture to get some hold of
> > this, or rather a walk-through with a certain pud-crossing
> > range in a folded 3-level scenario. Not sure if I would have
> > understood my explanation above w/o that, but I hope you can
> > make some sense out of it. Or draw yourself a picture :-)
>
> What I don't understand is how does anything work with S390 today?
>
> If the fix is only to change pxx_addr_end() then than generic code
> like mm/pagewalk.c will iterate over a *different list* of page table
> entries.
>
> It's choice of entries to look at is entirely driven by pxx_addr_end().
>
> Which suggest to me that mm/pagewalk.c also doesn't work properly
> today on S390 and this issue is not really about stack variables?
>
> Fundamentally if pXX_offset() and pXX_addr_end() must be consistent
> together, if pXX_offset() is folded then pXX_addr_end() must cause a
> single iteration of that level.
Your observation is correct.
Another way to describe the problem is existing pXd_addr_end helpers
could be applied to mismatching levels on s390 (e.g p4d_addr_end
applied to pud or pgd_addr_end applied to p4d). As you noticed,
all *_pXd_range iterators could be called with address ranges that
exceed single pXd table.
However, when it happens with pointers to real page tables (passed to
*_pXd_range iterators) we still operate on valid tables, which just
(lucky for us) happened to be folded. Thus we still reference correct
table entries.
It is only gup_fast case that exposes the issue. It hits because
pointers to stack copies are passed to gup_pXd_range iterators, not
pointers to real page tables itself.
As Gerald mentioned, it is very difficult to explain in a clear way.
Hopefully, one could make sense ot of it.
> Jason
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Steffen Maier @ 2020-09-10 9:18 UTC (permalink / raw)
To: Joe Perches, LKML, Jiri Kosina, Benjamin Block
Cc: linux-wireless, linux-fbdev, oss-drivers, nouveau, alsa-devel,
dri-devel, linux-ide, dm-devel, linux-mtd, linux-i2c, sparclinux,
kvmarm, linux-rtc, linux-s390, linux-scsi, dccp, linux-rdma,
linux-atm-general, linux-afs, coreteam, intel-wired-lan,
linux-serial, linux-input, linux-mmc, Kees Cook, linux-media,
linux-pm, intel-gfx, linux-sctp, linux-mediatek, linux-nvme,
storagedev, ceph-devel, linux-arm-kernel, linux-nfs, linux-parisc,
netdev, linux-usb, Nick Desaulniers, linux-mips, iommu,
netfilter-devel, linux-crypto, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
On 9/9/20 10:06 PM, Joe Perches wrote:
> fallthrough to a separate case/default label break; isn't very readable.
>
> Convert pseudo-keyword fallthrough; statements to a simple break; when
> the next label is case or default and the only statement in the next
> label block is break;
>
> Found using:
>
> $ grep-2.5.4 -rP --include=*.[ch] -n "fallthrough;(\s*(case\s+\w+|default)\s*:\s*){1,7}break;" *
>
> Miscellanea:
>
> o Move or coalesce a couple label blocks above a default: block.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> Compiled allyesconfig x86-64 only.
> A few files for other arches were not compiled.
> drivers/s390/scsi/zfcp_fsf.c | 2 +-
> 82 files changed, 109 insertions(+), 112 deletions(-)
> diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
> index 140186fe1d1e..2741a07df692 100644
> --- a/drivers/s390/scsi/zfcp_fsf.c
> +++ b/drivers/s390/scsi/zfcp_fsf.c
> @@ -2105,7 +2105,7 @@ static void zfcp_fsf_open_lun_handler(struct zfcp_fsf_req *req)
>
> case FSF_PORT_HANDLE_NOT_VALID:
> zfcp_erp_adapter_reopen(adapter, 0, "fsouh_1");
> - fallthrough;
> + break;
> case FSF_LUN_ALREADY_OPEN:
> break;
> case FSF_PORT_BOXED:
Acked-by: Steffen Maier <maier@linux.ibm.com> # for zfcp
--
Mit freundlichen Gruessen / Kind regards
Steffen Maier
Linux on IBM Z Development
https://www.ibm.com/privacy/us/en/
IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Matthias Hartmann
Geschaeftsfuehrung: Dirk Wittkopp
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Ilya Dryomov @ 2020-09-10 9:24 UTC (permalink / raw)
To: Joe Perches
Cc: linux-wireless, linux-fbdev, oss-drivers, nouveau, alsa-devel,
dri-devel, linux-mips, linux-ide, dm-devel, linux-mtd, linux-i2c,
sparclinux, kvmarm, linux-rtc, linux-s390, linux-scsi, dccp,
linux-rdma, linux-atm-general, linux-afs, coreteam,
intel-wired-lan, linux-serial, linux-input, linux-mmc, Kees Cook,
linux-media, linux-pm, intel-gfx, linux-sctp, linux-mediatek,
linux-nvme, storagedev, Ceph Development, linux-arm-kernel,
linux-nfs, Jiri Kosina, linux-parisc, netdev, linux-usb,
Nick Desaulniers, LKML, iommu, netfilter-devel,
Linux Crypto Mailing List, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
On Wed, Sep 9, 2020 at 10:10 PM Joe Perches <joe@perches.com> wrote:
>
> fallthrough to a separate case/default label break; isn't very readable.
>
> Convert pseudo-keyword fallthrough; statements to a simple break; when
> the next label is case or default and the only statement in the next
> label block is break;
>
> Found using:
>
> $ grep-2.5.4 -rP --include=*.[ch] -n "fallthrough;(\s*(case\s+\w+|default)\s*:\s*){1,7}break;" *
>
> Miscellanea:
>
> o Move or coalesce a couple label blocks above a default: block.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> Compiled allyesconfig x86-64 only.
> A few files for other arches were not compiled.
>
> arch/arm/mach-mmp/pm-pxa910.c | 2 +-
> arch/arm64/kvm/handle_exit.c | 2 +-
> arch/mips/kernel/cpu-probe.c | 2 +-
> arch/mips/math-emu/cp1emu.c | 2 +-
> arch/s390/pci/pci.c | 2 +-
> crypto/tcrypt.c | 4 ++--
> drivers/ata/sata_mv.c | 2 +-
> drivers/atm/lanai.c | 2 +-
> drivers/gpu/drm/i915/display/intel_sprite.c | 2 +-
> drivers/gpu/drm/nouveau/nvkm/engine/disp/hdmi.c | 2 +-
> drivers/hid/wacom_wac.c | 2 +-
> drivers/i2c/busses/i2c-i801.c | 2 +-
> drivers/infiniband/ulp/rtrs/rtrs-clt.c | 14 +++++++-------
> drivers/infiniband/ulp/rtrs/rtrs-srv.c | 6 +++---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +-
> drivers/irqchip/irq-vic.c | 4 ++--
> drivers/md/dm.c | 2 +-
> drivers/media/dvb-frontends/drxd_hard.c | 2 +-
> drivers/media/i2c/ov5640.c | 2 +-
> drivers/media/i2c/ov6650.c | 5 ++---
> drivers/media/i2c/smiapp/smiapp-core.c | 2 +-
> drivers/media/i2c/tvp5150.c | 2 +-
> drivers/media/pci/ddbridge/ddbridge-core.c | 2 +-
> drivers/media/usb/cpia2/cpia2_core.c | 2 +-
> drivers/mfd/iqs62x.c | 3 +--
> drivers/mmc/host/atmel-mci.c | 2 +-
> drivers/mtd/nand/raw/nandsim.c | 2 +-
> drivers/net/ethernet/intel/e1000e/phy.c | 2 +-
> drivers/net/ethernet/intel/fm10k/fm10k_pf.c | 2 +-
> drivers/net/ethernet/intel/i40e/i40e_adminq.c | 2 +-
> drivers/net/ethernet/intel/i40e/i40e_txrx.c | 2 +-
> drivers/net/ethernet/intel/iavf/iavf_txrx.c | 2 +-
> drivers/net/ethernet/intel/igb/e1000_phy.c | 2 +-
> drivers/net/ethernet/intel/ixgbe/ixgbe_82599.c | 2 +-
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 2 +-
> drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 2 +-
> drivers/net/ethernet/intel/ixgbevf/vf.c | 2 +-
> drivers/net/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c | 2 +-
> drivers/net/ethernet/qlogic/qed/qed_mcp.c | 2 +-
> drivers/net/ethernet/sfc/falcon/farch.c | 2 +-
> drivers/net/ethernet/sfc/farch.c | 2 +-
> drivers/net/phy/adin.c | 3 +--
> drivers/net/usb/pegasus.c | 4 ++--
> drivers/net/usb/usbnet.c | 2 +-
> drivers/net/wireless/ath/ath5k/eeprom.c | 2 +-
> drivers/net/wireless/mediatek/mt7601u/dma.c | 8 ++++----
> drivers/nvme/host/core.c | 12 ++++++------
> drivers/pcmcia/db1xxx_ss.c | 4 ++--
> drivers/power/supply/abx500_chargalg.c | 2 +-
> drivers/power/supply/charger-manager.c | 2 +-
> drivers/rtc/rtc-pcf85063.c | 2 +-
> drivers/s390/scsi/zfcp_fsf.c | 2 +-
> drivers/scsi/aic7xxx/aic79xx_core.c | 4 ++--
> drivers/scsi/aic94xx/aic94xx_tmf.c | 2 +-
> drivers/scsi/lpfc/lpfc_sli.c | 2 +-
> drivers/scsi/smartpqi/smartpqi_init.c | 2 +-
> drivers/scsi/sr.c | 2 +-
> drivers/tty/serial/sunsu.c | 2 +-
> drivers/tty/serial/sunzilog.c | 2 +-
> drivers/tty/vt/vt_ioctl.c | 2 +-
> drivers/usb/dwc3/core.c | 2 +-
> drivers/usb/gadget/legacy/inode.c | 2 +-
> drivers/usb/gadget/udc/pxa25x_udc.c | 4 ++--
> drivers/usb/host/ohci-hcd.c | 2 +-
> drivers/usb/isp1760/isp1760-hcd.c | 2 +-
> drivers/usb/musb/cppi_dma.c | 2 +-
> drivers/usb/phy/phy-fsl-usb.c | 2 +-
> drivers/video/fbdev/stifb.c | 2 +-
> fs/afs/yfsclient.c | 8 ++++----
> fs/ceph/dir.c | 2 +-
For ceph:
Acked-by: Ilya Dryomov <idryomov@gmail.com>
Thanks,
Ilya
^ permalink raw reply
* Re: [PATCH v3 3/7] mm/memory_hotplug: prepare passing flags to add_memory() and friends
From: Pankaj Gupta @ 2020-09-10 9:53 UTC (permalink / raw)
To: David Hildenbrand
Cc: linux-hyperv, Michal Hocko, Michael S. Tsirkin, Jason Wang,
Pingfan Liu, virtualization, Linux MM, Paul Mackerras,
K. Y. Srinivasan, Boris Ostrovsky, linux-s390, Wei Liu,
Stefano Stabellini, Dave Jiang, Baoquan He, Jason Gunthorpe,
linux-acpi, xen-devel, Heiko Carstens, Len Brown, Nathan Lynch,
Vasily Gorbik, Leonardo Bras, Haiyang Zhang, Stephen Hemminger,
Dan Williams, Christian Borntraeger, Juergen Gross,
Libor Pechacek, Greg Kroah-Hartman, linux-nvdimm,
Rafael J. Wysocki, LKML, Wei Yang, Vishal Verma,
Oliver O'Halloran, Andrew Morton, linuxppc-dev
In-Reply-To: <20200910091340.8654-4-david@redhat.com>
> We soon want to pass flags, e.g., to mark added System RAM resources.
> mergeable. Prepare for that.
>
> This patch is based on a similar patch by Oscar Salvador:
>
> https://lkml.kernel.org/r/20190625075227.15193-3-osalvador@suse.de
>
> Acked-by: Wei Liu <wei.liu@kernel.org>
> Reviewed-by: Juergen Gross <jgross@suse.com> # Xen related part
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: "Oliver O'Halloran" <oohall@gmail.com>
> Cc: Pingfan Liu <kernelfans@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Libor Pechacek <lpechacek@suse.cz>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Leonardo Bras <leobras.c@gmail.com>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-acpi@vger.kernel.org
> Cc: linux-nvdimm@lists.01.org
> Cc: linux-hyperv@vger.kernel.org
> Cc: linux-s390@vger.kernel.org
> Cc: virtualization@lists.linux-foundation.org
> Cc: xen-devel@lists.xenproject.org
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> arch/powerpc/platforms/powernv/memtrace.c | 2 +-
> arch/powerpc/platforms/pseries/hotplug-memory.c | 2 +-
> drivers/acpi/acpi_memhotplug.c | 3 ++-
> drivers/base/memory.c | 3 ++-
> drivers/dax/kmem.c | 2 +-
> drivers/hv/hv_balloon.c | 2 +-
> drivers/s390/char/sclp_cmd.c | 2 +-
> drivers/virtio/virtio_mem.c | 2 +-
> drivers/xen/balloon.c | 2 +-
> include/linux/memory_hotplug.h | 16 ++++++++++++----
> mm/memory_hotplug.c | 14 +++++++-------
> 11 files changed, 30 insertions(+), 20 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
> index 13b369d2cc454..6828108486f83 100644
> --- a/arch/powerpc/platforms/powernv/memtrace.c
> +++ b/arch/powerpc/platforms/powernv/memtrace.c
> @@ -224,7 +224,7 @@ static int memtrace_online(void)
> ent->mem = 0;
> }
>
> - if (add_memory(ent->nid, ent->start, ent->size)) {
> + if (add_memory(ent->nid, ent->start, ent->size, MHP_NONE)) {
> pr_err("Failed to add trace memory to node %d\n",
> ent->nid);
> ret += 1;
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 0ea976d1cac47..e1c9fa0d730f5 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -615,7 +615,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
> nid = memory_add_physaddr_to_nid(lmb->base_addr);
>
> /* Add the memory */
> - rc = __add_memory(nid, lmb->base_addr, block_sz);
> + rc = __add_memory(nid, lmb->base_addr, block_sz, MHP_NONE);
> if (rc) {
> invalidate_lmb_associativity_index(lmb);
> return rc;
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index e294f44a78504..2067c3bc55763 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -207,7 +207,8 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
> if (node < 0)
> node = memory_add_physaddr_to_nid(info->start_addr);
>
> - result = __add_memory(node, info->start_addr, info->length);
> + result = __add_memory(node, info->start_addr, info->length,
> + MHP_NONE);
>
> /*
> * If the memory block has been used by the kernel, add_memory()
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 4db3c660de831..b4c297dd04755 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -432,7 +432,8 @@ static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
>
> nid = memory_add_physaddr_to_nid(phys_addr);
> ret = __add_memory(nid, phys_addr,
> - MIN_MEMORY_BLOCK_SIZE * sections_per_block);
> + MIN_MEMORY_BLOCK_SIZE * sections_per_block,
> + MHP_NONE);
>
> if (ret)
> goto out;
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index 7dcb2902e9b1b..896cb9444e727 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -95,7 +95,7 @@ int dev_dax_kmem_probe(struct dev_dax *dev_dax)
> * this as RAM automatically.
> */
> rc = add_memory_driver_managed(numa_node, range.start,
> - range_len(&range), kmem_name);
> + range_len(&range), kmem_name, MHP_NONE);
>
> res->flags |= IORESOURCE_BUSY;
> if (rc) {
> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> index 32e3bc0aa665a..3c0d52e244520 100644
> --- a/drivers/hv/hv_balloon.c
> +++ b/drivers/hv/hv_balloon.c
> @@ -726,7 +726,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
>
> nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
> ret = add_memory(nid, PFN_PHYS((start_pfn)),
> - (HA_CHUNK << PAGE_SHIFT));
> + (HA_CHUNK << PAGE_SHIFT), MHP_NONE);
>
> if (ret) {
> pr_err("hot_add memory failed error is %d\n", ret);
> diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
> index a864b21af602a..f6e97f0830f64 100644
> --- a/drivers/s390/char/sclp_cmd.c
> +++ b/drivers/s390/char/sclp_cmd.c
> @@ -406,7 +406,7 @@ static void __init add_memory_merged(u16 rn)
> if (!size)
> goto skip_add;
> for (addr = start; addr < start + size; addr += block_size)
> - add_memory(0, addr, block_size);
> + add_memory(0, addr, block_size, MHP_NONE);
> skip_add:
> first_rn = rn;
> num = 1;
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index 834b7c13ef3dc..ed99e43354010 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -424,7 +424,7 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id)
>
> dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id);
> return add_memory_driver_managed(nid, addr, memory_block_size_bytes(),
> - vm->resource_name);
> + vm->resource_name, MHP_NONE);
> }
>
> /*
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 51427c752b37b..9f40a294d398d 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -331,7 +331,7 @@ static enum bp_state reserve_additional_memory(void)
> mutex_unlock(&balloon_mutex);
> /* add_memory_resource() requires the device_hotplug lock */
> lock_device_hotplug();
> - rc = add_memory_resource(nid, resource);
> + rc = add_memory_resource(nid, resource, MHP_NONE);
> unlock_device_hotplug();
> mutex_lock(&balloon_mutex);
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 51a877fec8da8..e53d1058f3443 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -57,6 +57,12 @@ enum {
> MMOP_ONLINE_MOVABLE,
> };
>
> +/* Flags for add_memory() and friends to specify memory hotplug details. */
> +typedef int __bitwise mhp_t;
> +
> +/* No special request */
> +#define MHP_NONE ((__force mhp_t)0)
> +
> /*
> * Extended parameters for memory hotplug:
> * altmap: alternative allocator for memmap array (optional)
> @@ -345,11 +351,13 @@ extern void set_zone_contiguous(struct zone *zone);
> extern void clear_zone_contiguous(struct zone *zone);
>
> extern void __ref free_area_init_core_hotplug(int nid);
> -extern int __add_memory(int nid, u64 start, u64 size);
> -extern int add_memory(int nid, u64 start, u64 size);
> -extern int add_memory_resource(int nid, struct resource *resource);
> +extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
> +extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
> +extern int add_memory_resource(int nid, struct resource *resource,
> + mhp_t mhp_flags);
> extern int add_memory_driver_managed(int nid, u64 start, u64 size,
> - const char *resource_name);
> + const char *resource_name,
> + mhp_t mhp_flags);
> extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
> unsigned long nr_pages,
> struct vmem_altmap *altmap, int migratetype);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 8e1cd18b5cf14..8f0bd7c9a63a5 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1039,7 +1039,7 @@ static int online_memory_block(struct memory_block *mem, void *arg)
> *
> * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
> */
> -int __ref add_memory_resource(int nid, struct resource *res)
> +int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
> {
> struct mhp_params params = { .pgprot = PAGE_KERNEL };
> u64 start, size;
> @@ -1118,7 +1118,7 @@ int __ref add_memory_resource(int nid, struct resource *res)
> }
>
> /* requires device_hotplug_lock, see add_memory_resource() */
> -int __ref __add_memory(int nid, u64 start, u64 size)
> +int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
> {
> struct resource *res;
> int ret;
> @@ -1127,18 +1127,18 @@ int __ref __add_memory(int nid, u64 start, u64 size)
> if (IS_ERR(res))
> return PTR_ERR(res);
>
> - ret = add_memory_resource(nid, res);
> + ret = add_memory_resource(nid, res, mhp_flags);
> if (ret < 0)
> release_memory_resource(res);
> return ret;
> }
>
> -int add_memory(int nid, u64 start, u64 size)
> +int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
> {
> int rc;
>
> lock_device_hotplug();
> - rc = __add_memory(nid, start, size);
> + rc = __add_memory(nid, start, size, mhp_flags);
> unlock_device_hotplug();
>
> return rc;
> @@ -1167,7 +1167,7 @@ EXPORT_SYMBOL_GPL(add_memory);
> * "System RAM ($DRIVER)".
> */
> int add_memory_driver_managed(int nid, u64 start, u64 size,
> - const char *resource_name)
> + const char *resource_name, mhp_t mhp_flags)
> {
> struct resource *res;
> int rc;
> @@ -1185,7 +1185,7 @@ int add_memory_driver_managed(int nid, u64 start, u64 size,
> goto out_unlock;
> }
>
> - rc = add_memory_resource(nid, res);
> + rc = add_memory_resource(nid, res, mhp_flags);
> if (rc < 0)
> release_memory_resource(res);
>
> --
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> 2.26.2
>
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Matthias Brugger @ 2020-09-10 10:16 UTC (permalink / raw)
To: Joe Perches, LKML, Jiri Kosina
Cc: linux-fbdev, oss-drivers, nouveau, alsa-devel, dri-devel,
linux-mips, linux-ide, dm-devel, linux-mtd, linux-i2c, sparclinux,
linux-afs, linux-rtc, linux-s390, linux-scsi, dccp, linux-rdma,
linux-atm-general, kvmarm, coreteam, intel-wired-lan,
linux-serial, linux-input, linux-mmc, Kees Cook, linux-media,
linux-pm, intel-gfx, linux-mediatek, linux-nvme, storagedev,
ceph-devel, linux-arm-kernel, Nick Desaulniers, linux-nfs,
linux-parisc, netdev, linux-usb, linux-wireless, linux-sctp,
iommu, netfilter-devel, linux-crypto, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
On 09/09/2020 22:06, Joe Perches wrote:
> diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
> index 09f931d4598c..778be26d329f 100644
> --- a/drivers/net/wireless/mediatek/mt7601u/dma.c
> +++ b/drivers/net/wireless/mediatek/mt7601u/dma.c
> @@ -193,11 +193,11 @@ static void mt7601u_complete_rx(struct urb *urb)
> case -ESHUTDOWN:
> case -ENOENT:
> return;
> + case 0:
> + break;
> default:
> dev_err_ratelimited(dev->dev, "rx urb failed: %d\n",
> urb->status);
> - fallthrough;
> - case 0:
> break;
> }
>
> @@ -238,11 +238,11 @@ static void mt7601u_complete_tx(struct urb *urb)
> case -ESHUTDOWN:
> case -ENOENT:
> return;
> + case 0:
> + break;
> default:
> dev_err_ratelimited(dev->dev, "tx urb failed: %d\n",
> urb->status);
> - fallthrough;
> - case 0:
> break;
> }
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
^ permalink raw reply
* RE: remove the last set_fs() in common code, and remove it for x86 and powerpc v3
From: David Laight @ 2020-09-10 12:26 UTC (permalink / raw)
To: David Laight, 'Christophe Leroy',
'Linus Torvalds', Segher Boessenkool
Cc: linux-arch, Kees Cook, the arch/x86 maintainers, Nick Desaulniers,
Linux Kernel Mailing List, Christoph Hellwig, Luis Chamberlain,
Al Viro, linux-fsdevel, linuxppc-dev, Alexey Dobriyan
In-Reply-To: <59a64e9a210847b59f70f9bd2d02b5c3@AcuMS.aculab.com>
From: David Laight
> Sent: 10 September 2020 10:26
...
> > > I had an 'interesting' idea.
> > >
> > > Can you use a local asm register variable as an input and output to
> > > an 'asm volatile goto' statement?
> > >
> > > Well you can - but is it guaranteed to work :-)
> > >
> >
> > With gcc at least it should work according to
> > https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
> >
> > They even explicitely tell: "The only supported use for this feature is
> > to specify registers for input and output operands when calling Extended
> > asm "
>
> A quick test isn't good....
>
> int bar(char *z)
> {
> __label__ label;
> register int eax asm ("eax") = 6;
> asm volatile goto (" mov $1, %%eax" ::: "eax" : label);
> label:
> return eax;
> }
>
> 0000000000000040 <bar>:
> 40: b8 01 00 00 00 mov $0x1,%eax
> 45: b8 06 00 00 00 mov $0x6,%eax
> 4a: c3 retq
>
> although adding:
> asm volatile ("" : "+r" (eax));
> either side of the 'asm volatile goto' does fix it.
Actually this is pretty sound:
__label__ label;
register int eax asm ("eax");
// Ensure eax can't be reloaded from anywhere
// In particular it can't be reloaded after the asm goto line
asm volatile ("" : "=r" (eax));
// Provided gcc doesn't save eax here...
asm volatile goto ("xxxxx" ::: "eax" : label);
// ... and reload the saved value here.
// The input value here will be that modified by the 'asm goto'.
// Since this modifies eax it can't be moved before the 'asm goto'.
asm volatile ("" : "+r" (eax));
// So here eax must contain the value set by the "xxxxx" instructions.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply
* Re: [PATCH v2] cpuidle-pseries: Fix CEDE latency conversion from tb to us
From: Michael Ellerman @ 2020-09-10 12:55 UTC (permalink / raw)
To: Rafael J. Wysocki, Joel Stanley, Gautham R. Shenoy,
Vaidyanathan Srinivasan, Michael Ellerman
Cc: linuxppc-dev, linux-kernel, linux-pm
In-Reply-To: <1599125247-28488-1-git-send-email-ego@linux.vnet.ibm.com>
On Thu, 3 Sep 2020 14:57:27 +0530, Gautham R. Shenoy wrote:
> commit d947fb4c965c ("cpuidle: pseries: Fixup exit latency for
> CEDE(0)") sets the exit latency of CEDE(0) based on the latency values
> of the Extended CEDE states advertised by the platform. The values
> advertised by the platform are in timebase ticks. However the cpuidle
> framework requires the latency values in microseconds.
>
> If the tb-ticks value advertised by the platform correspond to a value
> smaller than 1us, during the conversion from tb-ticks to microseconds,
> in the current code, the result becomes zero. This is incorrect as it
> puts a CEDE state on par with the snooze state.
>
> [...]
Applied to powerpc/fixes.
[1/1] cpuidle: pseries: Fix CEDE latency conversion from tb to us
https://git.kernel.org/powerpc/c/1d3ee7df009a46440c58508b8819213c09503acd
cheers
^ permalink raw reply
* Re: [PATCH kernel] powerpc/dma: Fix dma_map_ops::get_required_mask
From: Michael Ellerman @ 2020-09-10 12:55 UTC (permalink / raw)
To: Alexey Kardashevskiy, linuxppc-dev
Cc: Oliver O'Halloran, Cédric Le Goater, Christoph Hellwig
In-Reply-To: <20200908015106.79661-1-aik@ozlabs.ru>
On Tue, 8 Sep 2020 11:51:06 +1000, Alexey Kardashevskiy wrote:
> There are 2 problems with it:
> 1. "<" vs expected "<<"
> 2. the shift number is an IOMMU page number mask, not an address mask
> as the IOMMU page shift is missing.
>
> This did not hit us before f1565c24b596 ("powerpc: use the generic
> dma_ops_bypass mode") because we had there additional code to handle
> bypass mask so this chunk (almost?) never executed. However there
> were reports that aacraid does not work with "iommu=nobypass".
> After f1565c24b596, aacraid (and probably others which call
> dma_get_required_mask() before setting the mask) was unable to
> enable 64bit DMA and fall back to using IOMMU which was known not to work,
> one of the problems is double free of an IOMMU page.
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/dma: Fix dma_map_ops::get_required_mask
https://git.kernel.org/powerpc/c/437ef802e0adc9f162a95213a3488e8646e5fc03
cheers
^ permalink raw reply
* Re: [PATCH v2] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute
From: Michael Ellerman @ 2020-09-10 12:55 UTC (permalink / raw)
To: linux-nvdimm, linuxppc-dev, Vaibhav Jain; +Cc: Aneesh Kumar K . V
In-Reply-To: <20200907110540.21349-1-vaibhav@linux.ibm.com>
On Mon, 7 Sep 2020 16:35:40 +0530, Vaibhav Jain wrote:
> The newly introduced 'perf_stats' attribute uses the default access
> mode of 0444 letting non-root users access performance stats of an
> nvdimm and potentially force the kernel into issuing large number of
> expensive HCALLs. Since the information exposed by this attribute
> cannot be cached hence its better to ward of access to this attribute
> from users who don't need to access these performance statistics.
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute
https://git.kernel.org/powerpc/c/0460534b532e5518c657c7d6492b9337d975eaa3
cheers
^ permalink raw reply
* Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
From: Jason Gunthorpe @ 2020-09-10 13:02 UTC (permalink / raw)
To: Alexander Gordeev
Cc: Peter Zijlstra, Dave Hansen, Dave Hansen, Paul Mackerras,
linux-sparc, Claudio Imbrenda, Will Deacon, linux-arch,
linux-s390, Vasily Gorbik, Richard Weinberger, linux-x86,
Russell King, Christian Borntraeger, Ingo Molnar, Catalin Marinas,
Andrey Ryabinin, Gerald Schaefer, Heiko Carstens, Arnd Bergmann,
John Hubbard, Jeff Dike, linux-um, Borislav Petkov,
Andy Lutomirski, Thomas Gleixner, linux-arm, linux-mm,
linux-power, LKML, Andrew Morton, Linus Torvalds, Mike Rapoport
In-Reply-To: <20200910093925.GB29166@oc3871087118.ibm.com>
On Thu, Sep 10, 2020 at 11:39:25AM +0200, Alexander Gordeev wrote:
> As Gerald mentioned, it is very difficult to explain in a clear way.
> Hopefully, one could make sense ot of it.
I would say the page table API requires this invariant:
pud = pud_offset(p4d, addr);
do {
WARN_ON(pud != pud_offset(p4d, addr);
next = pud_addr_end(addr, end);
} while (pud++, addr = next, addr != end);
ie pud++ is supposed to be a shortcut for
pud_offset(p4d, next)
While S390 does not follow this. Fixing addr_end brings it into
alignment by preventing pud++ from happening.
The only currently known side effect is that gup_fast crashes, but it
sure is an unexpected thing.
This suggests another fix, which is to say that pud++ is undefined and
pud_offset() must always be called, but I think that would cause worse
codegen on all other archs.
Jason
^ permalink raw reply
* Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
From: Gerald Schaefer @ 2020-09-10 13:11 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: Peter Zijlstra, Dave Hansen, Dave Hansen, Paul Mackerras,
linux-sparc, Alexander Gordeev, Claudio Imbrenda, Will Deacon,
linux-arch, linux-s390, Vasily Gorbik, Richard Weinberger,
linux-x86, Russell King, Christian Borntraeger, Ingo Molnar,
Catalin Marinas, Andrey Ryabinin, Heiko Carstens, Arnd Bergmann,
John Hubbard, Jeff Dike, linux-um, Borislav Petkov,
Andy Lutomirski, Thomas Gleixner, linux-arm, linux-mm,
linux-power, LKML, Andrew Morton, Linus Torvalds, Mike Rapoport
In-Reply-To: <20200909180324.GI87483@ziepe.ca>
On Wed, 9 Sep 2020 15:03:24 -0300
Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Wed, Sep 09, 2020 at 07:25:34PM +0200, Gerald Schaefer wrote:
> > I actually had to draw myself a picture to get some hold of
> > this, or rather a walk-through with a certain pud-crossing
> > range in a folded 3-level scenario. Not sure if I would have
> > understood my explanation above w/o that, but I hope you can
> > make some sense out of it. Or draw yourself a picture :-)
>
> What I don't understand is how does anything work with S390 today?
That is totally comprehensible :-)
> If the fix is only to change pxx_addr_end() then than generic code
> like mm/pagewalk.c will iterate over a *different list* of page table
> entries.
>
> It's choice of entries to look at is entirely driven by pxx_addr_end().
>
> Which suggest to me that mm/pagewalk.c also doesn't work properly
> today on S390 and this issue is not really about stack variables?
I guess you are confused by the fact that the generic change will indeed
change the logic for _all_ pagetable walkers on s390, not just for
the gup_fast case. But that doesn't mean that they were doing it wrong
before, we simply can do it both ways. However, we probably should
make that (in theory useless) change more explicit.
Let's compare before and after for mm/pagewalk.c on s390, with 3-level
pagetables, range crossing 2 GB pud boundary.
* Before (with pXd_addr_end always using static 5-level PxD_SIZE):
walk_pgd_range()
-> pgd_addr_end() will use static 2^53 PGDIR_SIZE, range is not cropped,
no iterations needed, passed over to next level
walk_p4d_range()
-> p4d_addr_end() will use static 2^42 P4D_SIZE, range still not cropped
walk_pud_range()
-> pud_addr_end() now we're cropping, with 2^31 PUD_SIZE, need two
iterations for range crossing pud boundary, doing
that right here on a pudp which is actually the
previously passed-through pgdp/p4dp (pointing to
correct pagetable entry)
* After (with dynamic pXd_addr_end using "correct" PxD_SIZE boundaries,
should be similar to other archs static "top-level folding"):
walk_pgd_range()
-> pgd_addr_end() will now determine "correct" boundary based on pgd
value, i.e. 2^31 PUD_SIZE, do cropping now, iteration
will now happen here
walk_p4d/pud_range()
-> operate on cropped range, will not iterate, instead return to pgd level,
which will then use the same pointer for iteration as in the "Before"
case, but not on the same level.
IMHO, our "Before" logic is more efficient, and also feels more natural.
After all, it is not really necessary to return to pgd level, and it will
surely cost some extra instructions. We are willing to take that cost
for the sake of doing it in a more generic way, hoping that will reduce
future issues. E.g. you already mentioned that you have plans for using
the READ_ONCE logic also in other places, and that would be such a
"future issue".
> Fundamentally if pXX_offset() and pXX_addr_end() must be consistent
> together, if pXX_offset() is folded then pXX_addr_end() must cause a
> single iteration of that level.
well, that sounds correct in theory, but I guess it depends on "how
you fold it". E.g. what does "if pXX_offset() is folded" mean?
Take pgd_offset() for the 3-level case above. From our previous
"middle-level folding/iteration" perspective, I would say that
pgd/p4d are folded into pud, so if you say "if pgd_offset() is folded
then pgd_addr_end() must cause a single iteration of that level",
we were doing it all correctly, i.e only having single iteration
on pgd/p4d level. You could even say that all others are doing /
using it wrong :-)
Now take pgd_offset() from the "top-level folding/iteration".
Here you would say that p4d/pud are folded into pgd, which again
does not sound like the natural / most efficient way to me,
but IIUC this has to be how it works for all other archs with
(static) pagetable folding. Now you'd say "if pud/p4d_offset()
is folded then pud/p4d_addr_end() must cause a single iteration
of that level", and that would sound correct. At least until
you look more closely, because e.g. p4d_addr_end() in
include/asm-generic/pgtable-nop4d.h is simply this:
#define p4d_addr_end(addr, end) (end)
How can that cause a single iteration? It clearly won't, it only
works because the previous pgd_addr_end already cropped the range
so that there will be only single iterations for p4d/pud.
The more I think of it, the more it sounds like s390 "middle-level
folding/iteration" was doing it "the right way", and everybody else
was wrong, or at least not in an optimally efficient way :-) Might
also be that only we could do this because we can determine the
pagetable level from a pagetable entry value.
Anyway, if you are not yet confused enough, I recommend looking
at the other option we had in mind, for fixing the gup_fast issue.
See "Patch 1" from here:
https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/
That would actually have kept that "middle-level iteration" also
for gup_fast, by additionally passing through the pXd pointers.
However, it also needed a gup-specific version of pXd_offset(),
in order to keep the READ_ONCE semantics. For s390, that would
have actually been the best solution, but a generic version of
that might not have been so easy. And doing it like everybody
else can not be so bad, at least I really hope so.
Of course, at some point in time, we might come up with some fancy
fundamental change that would "do it the right middle-level way
for everybody". At least I think I overheard Vasily and Alexander
discussing some wild ideas, but that is certainly beyond this scope
here...
^ permalink raw reply
* Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
From: Gerald Schaefer @ 2020-09-10 13:28 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: Peter Zijlstra, Dave Hansen, Dave Hansen, Paul Mackerras,
linux-sparc, Alexander Gordeev, Claudio Imbrenda, Will Deacon,
linux-arch, linux-s390, Vasily Gorbik, Richard Weinberger,
linux-x86, Russell King, Christian Borntraeger, Ingo Molnar,
Catalin Marinas, Andrey Ryabinin, Heiko Carstens, Arnd Bergmann,
John Hubbard, Jeff Dike, linux-um, Borislav Petkov,
Andy Lutomirski, Thomas Gleixner, linux-arm, linux-mm,
linux-power, LKML, Andrew Morton, Linus Torvalds, Mike Rapoport
In-Reply-To: <20200910130233.GK87483@ziepe.ca>
On Thu, 10 Sep 2020 10:02:33 -0300
Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Thu, Sep 10, 2020 at 11:39:25AM +0200, Alexander Gordeev wrote:
>
> > As Gerald mentioned, it is very difficult to explain in a clear way.
> > Hopefully, one could make sense ot of it.
>
> I would say the page table API requires this invariant:
>
> pud = pud_offset(p4d, addr);
> do {
> WARN_ON(pud != pud_offset(p4d, addr);
> next = pud_addr_end(addr, end);
> } while (pud++, addr = next, addr != end);
>
> ie pud++ is supposed to be a shortcut for
> pud_offset(p4d, next)
>
> While S390 does not follow this. Fixing addr_end brings it into
> alignment by preventing pud++ from happening.
>
> The only currently known side effect is that gup_fast crashes, but it
> sure is an unexpected thing.
It only is unexpected in a "top-level folding" world, see my other reply.
Consider it an optimization, which was possible because of how our dynamic
folding works, and e.g. because we can determine the correct pagetable
level from a pXd value in pXd_offset.
> This suggests another fix, which is to say that pud++ is undefined and
> pud_offset() must always be called, but I think that would cause worse
> codegen on all other archs.
There really is nothing to fix for s390 outside of gup_fast, or other
potential future READ_ONCE pagetable walkers. We do take the side-effect
of the generic change on all other pagetable walkers for s390, but it
really is rather a slight degradation than a fix.
^ permalink raw reply
* Re: [trivial PATCH] treewide: Convert switch/case fallthrough; to break;
From: Robin Murphy @ 2020-09-10 14:21 UTC (permalink / raw)
To: Joe Perches, LKML, Jiri Kosina
Cc: linux-fbdev, oss-drivers, nouveau, alsa-devel, dri-devel,
linux-mips, linux-ide, dm-devel, linux-mtd, linux-i2c, sparclinux,
Will Deacon, linux-afs, linux-rtc, linux-s390, linux-scsi, dccp,
linux-rdma, linux-atm-general, kvmarm, coreteam, intel-wired-lan,
linux-serial, linux-input, linux-mmc, Kees Cook, linux-media,
linux-pm, intel-gfx, linux-mediatek, linux-nvme, storagedev,
ceph-devel, linux-arm-kernel, Nick Desaulniers, linux-nfs,
linux-parisc, netdev, linux-usb, linux-wireless, linux-sctp,
iommu, netfilter-devel, linux-crypto, bpf, linuxppc-dev
In-Reply-To: <e6387578c75736d61b2fe70d9783d91329a97eb4.camel@perches.com>
On 2020-09-09 21:06, Joe Perches wrote:
> fallthrough to a separate case/default label break; isn't very readable.
>
> Convert pseudo-keyword fallthrough; statements to a simple break; when
> the next label is case or default and the only statement in the next
> label block is break;
>
> Found using:
>
> $ grep-2.5.4 -rP --include=*.[ch] -n "fallthrough;(\s*(case\s+\w+|default)\s*:\s*){1,7}break;" *
>
> Miscellanea:
>
> o Move or coalesce a couple label blocks above a default: block.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> Compiled allyesconfig x86-64 only.
> A few files for other arches were not compiled.
>
[...]
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index c192544e874b..743db1abec40 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -3777,7 +3777,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
> switch (FIELD_GET(IDR0_TTF, reg)) {
> case IDR0_TTF_AARCH32_64:
> smmu->ias = 40;
> - fallthrough;
> + break;
> case IDR0_TTF_AARCH64:
> break;
> default:
I have to say I don't really agree with the readability argument for
this one - a fallthrough is semantically correct here, since the first
case is a superset of the second. It just happens that anything we would
do for the common subset is implicitly assumed (there are other
potential cases we simply haven't added support for at the moment), thus
the second case is currently empty.
This change actively obfuscates that distinction.
Robin.
^ permalink raw reply
* [PATCH] soc: fsl: dpio: remove set but not used 'addr_cena'
From: Jason Yan @ 2020-09-10 14:04 UTC (permalink / raw)
To: Roy.Pledge, leoyang.li, youri.querry_1, linux-kernel,
linuxppc-dev, linux-arm-kernel
Cc: Hulk Robot, Jason Yan
This addresses the following gcc warning with "make W=1":
drivers/soc/fsl/dpio/qbman-portal.c: In function
‘qbman_swp_enqueue_multiple_direct’:
drivers/soc/fsl/dpio/qbman-portal.c:650:11: warning: variable
‘addr_cena’ set but not used [-Wunused-but-set-variable]
650 | uint64_t addr_cena;
| ^~~~~~~~~
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
---
drivers/soc/fsl/dpio/qbman-portal.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/soc/fsl/dpio/qbman-portal.c b/drivers/soc/fsl/dpio/qbman-portal.c
index 0ab85bfb116f..659b4a570d5b 100644
--- a/drivers/soc/fsl/dpio/qbman-portal.c
+++ b/drivers/soc/fsl/dpio/qbman-portal.c
@@ -647,7 +647,6 @@ int qbman_swp_enqueue_multiple_direct(struct qbman_swp *s,
const uint32_t *cl = (uint32_t *)d;
uint32_t eqcr_ci, eqcr_pi, half_mask, full_mask;
int i, num_enqueued = 0;
- uint64_t addr_cena;
spin_lock(&s->access_spinlock);
half_mask = (s->eqcr.pi_ci_mask>>1);
@@ -701,7 +700,6 @@ int qbman_swp_enqueue_multiple_direct(struct qbman_swp *s,
/* Flush all the cacheline without load/store in between */
eqcr_pi = s->eqcr.pi;
- addr_cena = (size_t)s->addr_cena;
for (i = 0; i < num_enqueued; i++)
eqcr_pi++;
s->eqcr.pi = eqcr_pi & full_mask;
--
2.25.4
^ permalink raw reply related
* Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
From: Jason Gunthorpe @ 2020-09-10 15:10 UTC (permalink / raw)
To: Gerald Schaefer, Anshuman Khandual
Cc: Peter Zijlstra, Dave Hansen, Dave Hansen, Paul Mackerras,
linux-sparc, Alexander Gordeev, Claudio Imbrenda, Will Deacon,
linux-arch, linux-s390, Vasily Gorbik, Richard Weinberger,
linux-x86, Russell King, Christian Borntraeger, Ingo Molnar,
Catalin Marinas, Andrey Ryabinin, Heiko Carstens, Arnd Bergmann,
John Hubbard, Jeff Dike, linux-um, Borislav Petkov,
Andy Lutomirski, Thomas Gleixner, linux-arm, linux-mm,
linux-power, LKML, Andrew Morton, Linus Torvalds, Mike Rapoport
In-Reply-To: <20200910152803.1a930afc@thinkpad>
On Thu, Sep 10, 2020 at 03:28:03PM +0200, Gerald Schaefer wrote:
> On Thu, 10 Sep 2020 10:02:33 -0300
> Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> > On Thu, Sep 10, 2020 at 11:39:25AM +0200, Alexander Gordeev wrote:
> >
> > > As Gerald mentioned, it is very difficult to explain in a clear way.
> > > Hopefully, one could make sense ot of it.
> >
> > I would say the page table API requires this invariant:
> >
> > pud = pud_offset(p4d, addr);
> > do {
> > WARN_ON(pud != pud_offset(p4d, addr);
> > next = pud_addr_end(addr, end);
> > } while (pud++, addr = next, addr != end);
> >
> > ie pud++ is supposed to be a shortcut for
> > pud_offset(p4d, next)
> >
> > While S390 does not follow this. Fixing addr_end brings it into
> > alignment by preventing pud++ from happening.
> >
> > The only currently known side effect is that gup_fast crashes, but it
> > sure is an unexpected thing.
>
> It only is unexpected in a "top-level folding" world, see my other reply.
> Consider it an optimization, which was possible because of how our dynamic
> folding works, and e.g. because we can determine the correct pagetable
> level from a pXd value in pXd_offset.
No, I disagree. The page walker API the arch presents has to have well
defined semantics. For instance, there is an effort to define tests
and invarients for the page table accesses to bring this understanding
and uniformity:
mm/debug_vm_pgtable.c
If we fix S390 using the pX_addr_end() change then the above should be
updated with an invariant to check it. I've added Anshuman for some
thoughts..
For better or worse, that invariant does exclude arches from using
other folding techniques.
The other solution would be to address the other side of != and adjust
the pud++
eg replcae pud++ with something like:
pud = pud_next_entry(p4d, pud, next)
Such that:
pud_next_entry(p4d, pud, next) === pud_offset(p4d, next)
In which case the invarient changes to 'callers can never do pointer
arithmetic on the result of pXX_offset()' which is a bit harder to
enforce.
Jason
^ permalink raw reply
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