[RFC PATCH v2 00/12] PCI core learns hotplug

[RFC PATCH v2 00/12] PCI core learns hotplug

[Alex Chiang]

Hi all,

Jesse asked me to send out some updated bits on this series to get
more early review. He notes that there is at least one patch out there
(Yuji Shimada's memory resource alignment) that would really like this.

Original discussion here:

	http://thread.gmane.org/gmane.linux.kernel.pci/2914

This is still a work-in-progress.

Known to work:
	- remove any device in PCI tree once, rescan to get it back
	- device seems to be functional. :)
	- can repeat above multiple times on non PCIe machines

Known to not work:
	- can't remove/rescan multiple times when PCIe port driver is loaded
	- hotplug drivers using pci_do_scan_bus may blow up

TODO:
	- fix known PCIe port driver bug
	- clean up hotplug drivers using pci_do_scan_bus
	- incorporate one more of Trent's patches, will probably replace
	  "Introduce /sys/bus/pci/rescan" since his implementation was nicer
	- remove ASPM patch once jbarnes's linux-next tree gets rebased ;)

Comments welcom.

Thanks.

/ac

v1 -> v2:	
	- incorporated lots of Trent Piepho's work
	- beefed up pci_do_scan_bus as heavy lifter for rescanning
	- small bugfixes folded into earlier patches to get everything working
---

Alex Chiang (8):
      PCI: more whitespace cleanups
      PCI Hotplug: schedule fakephp for feature removal
      PCI Hotplug: rename legacy_fakephp to fakephp
      PCI: Introduce /sys/bus/pci/devices/.../rescan
      PCI: Introduce /sys/bus/pci/rescan
      PCI: beef up pci_do_scan_bus()
      PCI: properly clean up ASPM link state on device remove
      PCI: always scan child buses

Trent Piepho (4):
      PCI Hotplug: restore fakephp interface with complete reimplementation
      PCI: Introduce /sys/bus/pci/devices/.../remove
      PCI: pci_scan_slot() returns newly found devices
      PCI: don't scan existing devices


 Documentation/ABI/testing/sysfs-bus-pci    |   27 ++
 Documentation/feature-removal-schedule.txt |   32 ++
 Documentation/filesystems/sysfs-pci.txt    |    9 +
 drivers/pci/hotplug-pci.c                  |   16 +
 drivers/pci/hotplug/fakephp.c              |  443 +++++++---------------------
 drivers/pci/pci-sysfs.c                    |   96 +++++-
 drivers/pci/pcie/aspm.c                    |    4 
 drivers/pci/probe.c                        |   90 +++---
 drivers/pci/remove.c                       |    4 
 9 files changed, 323 insertions(+), 398 deletions(-)

[RFC PATCH v2 01/12] PCI: don't scan existing devices

[Alex Chiang]

From: Trent Piepho <xyzzy@speakeasy.org>

pci_scan_single_device is supposed to add newly discovered
devices to pci_bus->devices, but doesn't check to see if the
device has already been added. This can cause problems if we ever
want to use this interface to rescan the PCI bus.

If the device is already added, just return it.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/probe.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 55ec44a..66b5d1c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1006,6 +1006,12 @@ struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn)
 {
 	struct pci_dev *dev;
 
+	dev = pci_get_slot(bus, devfn);
+	if (dev) {
+		pci_dev_put(dev);
+		return dev;
+	}
+
 	dev = pci_scan_device(bus, devfn);
 	if (!dev)
 		return NULL;

[RFC PATCH v2 02/12] PCI: pci_scan_slot() returns newly found devices

[Alex Chiang]

From: Trent Piepho <xyzzy@speakeasy.org>

pci_scan_slot() has been rewritten to be less complex and will now
return the number of *new* devices found.

Existing callers need not worry because they already assume that
they can't call pci_scan_slot() on an already-scanned slot.

Thus, there is no semantic change for existing callers: returning
newly found devices (this patch) is exactly equal to returning all
found devices (before this patch).

This patch adds some more groundwork to allow us to rescan the
PCI bus during runtime to discover newly added devices.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/probe.c |   35 +++++++++++++----------------------
 1 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 66b5d1c..d392813 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1030,35 +1030,26 @@ EXPORT_SYMBOL(pci_scan_single_device);
  * Scan a PCI slot on the specified PCI bus for devices, adding
  * discovered devices to the @bus->devices list.  New devices
  * will not have is_added set.
+ *
+ * Returns the number of new devices found.
  */
 int pci_scan_slot(struct pci_bus *bus, int devfn)
 {
-	int func, nr = 0;
-	int scan_all_fns;
-
-	scan_all_fns = pcibios_scan_all_fns(bus, devfn);
-
-	for (func = 0; func < 8; func++, devfn++) {
-		struct pci_dev *dev;
+	int fn, nr = 0;
+	struct pci_dev *dev;
 
-		dev = pci_scan_single_device(bus, devfn);
-		if (dev) {
+	if ((dev = pci_scan_single_device(bus, devfn)))
+		if (!dev->is_added)	/* new device? */
 			nr++;
 
-			/*
-		 	 * If this is a single function device,
-		 	 * don't scan past the first function.
-		 	 */
-			if (!dev->multifunction) {
-				if (func > 0) {
-					dev->multifunction = 1;
-				} else {
- 					break;
-				}
+	if ((dev && dev->multifunction) ||
+	    (!dev && pcibios_scan_all_fns(bus, devfn))) {
+		for (fn = 1; fn < 8; fn++) {
+			if ((dev = pci_scan_single_device(bus, devfn + fn))) {
+				if (!dev->is_added)
+					nr++;
+				dev->multifunction = 1;
 			}
-		} else {
-			if (func == 0 && !scan_all_fns)
-				break;
 		}
 	}
 

[RFC PATCH v2 03/12] PCI: always scan child buses

[Alex Chiang]

While scanning bridges, we stop our scan if we encounter a bus
that we've seen before, to work around some buggy chipsets. This
is a good idea, but prevents us from fully scanning the PCI bus
at a future time (to find newly hot-added devices, for example).

Change the logic so that we skip _re-adding_ an existing bus
that we've seen before, but also allow the scan to descend to
all child buses.

Now that we're potentially scanning our child buses again, we
also need to be sure not to attempt re-initializing their BARs
so we avoid that.

This patch lays the groundwork to allow the user to issue a
rescan of the PCI bus at any time.

Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/probe.c |   33 +++++++++++++++++++--------------
 1 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d392813..d2bd1b0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -511,21 +511,21 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 
 		/*
 		 * If we already got to this bus through a different bridge,
-		 * ignore it.  This can happen with the i450NX chipset.
+		 * don't re-add it. This can happen with the i450NX chipset.
+		 *
+		 * However, we continue to descend down the hierarchy and
+		 * scan remaining child buses.
 		 */
-		if (pci_find_bus(pci_domain_nr(bus), busnr)) {
-			dev_info(&dev->dev, "bus %04x:%02x already known\n",
-				 pci_domain_nr(bus), busnr);
-			goto out;
+		child = pci_find_bus(pci_domain_nr(bus), busnr);
+		if (!child) {
+			child = pci_add_new_bus(bus, dev, busnr);
+			if (!child)
+				goto out;
+			child->primary = buses & 0xFF;
+			child->subordinate = (buses >> 16) & 0xFF;
+			child->bridge_ctl = bctl;
 		}
 
-		child = pci_add_new_bus(bus, dev, busnr);
-		if (!child)
-			goto out;
-		child->primary = buses & 0xFF;
-		child->subordinate = (buses >> 16) & 0xFF;
-		child->bridge_ctl = bctl;
-
 		cmax = pci_scan_child_bus(child);
 		if (cmax > max)
 			max = cmax;
@@ -1075,8 +1075,13 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
 	 * After performing arch-dependent fixup of the bus, look behind
 	 * all PCI-to-PCI bridges on this bus.
 	 */
-	pr_debug("PCI: Fixups for bus %04x:%02x\n", pci_domain_nr(bus), bus->number);
-	pcibios_fixup_bus(bus);
+	if (!bus->is_added) {
+		pr_debug("PCI: Fixups for bus %04x:%02x\n", pci_domain_nr(bus), bus->number);
+		pcibios_fixup_bus(bus);
+		if (bus->parent == NULL)
+			bus->is_added = 1;
+	}
+
 	for (pass=0; pass < 2; pass++)
 		list_for_each_entry(dev, &bus->devices, bus_list) {
 			if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||

[RFC PATCH v2 04/12] PCI: properly clean up ASPM link state on device remove

[Alex Chiang]

We only want to disable ASPM when the last function is removed from
the parent's device list. We determine this by checking to see if
the parent's device list is completely empty.

Unfortunately, we never hit that code because the parent is considered
an upstream port, and never had an ASPM link_state associated with it.

The early check for !link_state causes us to return early, we never
discover that our device list is empty, and thus we never remove the
downstream ports' link_state nodes.

Instead of checking to see if the parent's device list is empty, we can
check to see if we are the last device on the list, and if so, then we
know that we can clean up properly.

Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/pcie/aspm.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 586b6f7..b0367f1 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -718,9 +718,9 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
 
 	/*
 	 * All PCIe functions are in one slot, remove one function will remove
-	 * the the whole slot, so just wait
+	 * the whole slot, so just wait until we are the last function left.
 	 */
-	if (!list_empty(&parent->subordinate->devices))
+	if (!list_is_last(&pdev->bus_list, &parent->subordinate->devices))
 		goto out;
 
 	/* All functions are removed, so just disable ASPM for the link */

[RFC PATCH v2 05/12] PCI: beef up pci_do_scan_bus()

[Alex Chiang]

We have a nice interface for re-scanning a PCI bus which will
discover newly added devices, add them to the device tree, and
enable them properly.

Ensure that the bridge resources are properly sized and assigned
during the rescan.

Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/hotplug-pci.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/hotplug-pci.c b/drivers/pci/hotplug-pci.c
index 4d4a644..33ab2d2 100644
--- a/drivers/pci/hotplug-pci.c
+++ b/drivers/pci/hotplug-pci.c
@@ -6,13 +6,21 @@
 
 unsigned int __devinit pci_do_scan_bus(struct pci_bus *bus)
 {
-	unsigned int max;
+	unsigned int max, pass;
+	struct pci_dev *dev;
 
 	max = pci_scan_child_bus(bus);
 
-	/*
-	 * Make the discovered devices available.
-	 */
+	for (pass=0; pass < 2; pass++)
+		list_for_each_entry(dev, &bus->devices, bus_list) {
+			if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
+			    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
+				if (pass && dev->subordinate)
+					pci_bus_size_bridges(dev->subordinate);
+		}
+
+	pci_bus_assign_resources(bus);
+	pci_enable_bridges(bus);
 	pci_bus_add_devices(bus);
 
 	return max;

[RFC PATCH v2 06/12] PCI: Introduce /sys/bus/pci/rescan

[Alex Chiang]

This interface allows the user to force a rescan of all PCI buses
in system, and rediscover devices that have been removed earlier.

Cc: Trent Piepho <xyzzy@speakeasy.org>
Cc: djwong@us.ibm.com
Reviewed-by: James Cameron <qz@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 Documentation/ABI/testing/sysfs-bus-pci |    9 +++++++++
 drivers/pci/pci-sysfs.c                 |   26 ++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index ceddcff..ba15e2e 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -1,3 +1,12 @@
+What:		/sys/bus/pci/rescan
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		force a rescan of all PCI buses in the system, and
+		re-discover previously removed devices.
+		Depends on CONFIG_HOTPLUG.
+
 What:		/sys/bus/pci/devices/.../vpd
 Date:		February 2008
 Contact:	Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index db7ec14..a2d85f6 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -956,12 +956,38 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
 	}
 }
 
+#ifdef CONFIG_HOTPLUG
+static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf, size_t count)
+{
+	unsigned long val;
+	struct pci_bus *b = NULL;
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (val)
+		while ((b = pci_find_next_bus(b)) != NULL)
+			pci_do_scan_bus(b);
+
+	return count;
+}
+static BUS_ATTR(rescan, S_IWUSR, NULL, bus_rescan_store);
+#endif
+
 static int __init pci_sysfs_init(void)
 {
 	struct pci_dev *pdev = NULL;
 	int retval;
 
 	sysfs_initialized = 1;
+#ifdef CONFIG_HOTPLUG
+	retval = bus_create_file(&pci_bus_type, &bus_attr_rescan);
+	if (retval)
+		return retval;
+#endif
 	for_each_pci_dev(pdev) {
 		retval = pci_create_sysfs_dev_files(pdev);
 		if (retval) {

[RFC PATCH v2 07/12] PCI: Introduce /sys/bus/pci/devices/.../remove

[Alex Chiang]

From: Trent Piepho <xyzzy@speakeasy.org>

This patch adds an attribute named "remove" to a PCI device's sysfs
directory.  Writing a non-zero value to this attribute will remove the PCI
device and any children of it.

[achiang@hp.com: document in Documentation/ABI]
[achiang@hp.com: add #ifdef CONFIG_HOTPLUG]
[achiang@hp.com: need final pci_dev_put in remove_callback]
Cc: djwong@us.ibm.com
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 Documentation/ABI/testing/sysfs-bus-pci |    8 ++++++++
 Documentation/filesystems/sysfs-pci.txt |    9 +++++++++
 drivers/pci/pci-sysfs.c                 |   32 +++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index ba15e2e..8c0abc7 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -7,6 +7,14 @@ Description:
 		re-discover previously removed devices.
 		Depends on CONFIG_HOTPLUG.
 
+What:		/sys/bus/pci/devices/.../remove
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		hot-remove the PCI device and any of its children.
+		Depends on CONFIG_HOTPLUG.
+
 What:		/sys/bus/pci/devices/.../vpd
 Date:		February 2008
 Contact:	Ben Hutchings <bhutchings@solarflare.com>
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 68ef488..54e014f 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -11,6 +11,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- device
      |   |-- irq
      |   |-- local_cpus
+     |   |-- remove
      |   |-- resource
      |   |-- resource0
      |   |-- resource1
@@ -34,6 +35,7 @@ files, each with their own function.
        device		   PCI device (ascii, ro)
        irq		   IRQ number (ascii, ro)
        local_cpus	   nearby CPU mask (cpumask, ro)
+       remove		   remove device from kernel's list (ascii, wo)
        resource		   PCI resource host addresses (ascii, ro)
        resource0..N	   PCI resource N, if present (binary, mmap)
        resource0_wc..N_wc  PCI WC map resource N, if prefetchable (binary, mmap)
@@ -44,6 +46,7 @@ files, each with their own function.
 
   ro - read only file
   rw - file is readable and writable
+  wo - write only file
   mmap - file is mmapable
   ascii - file contains ascii text
   binary - file contains binary data
@@ -62,6 +65,12 @@ ROM file, if available.  It's disabled by default, however, so applications
 should write the string "1" to the file to enable it before attempting a read
 call, and disable it following the access by writing "0" to the file.
 
+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file.  This does not involve any kind of hot-plug functionality,
+e.g. powering off the device.  The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it removed, and the device will be removed
+from any drivers attached to it.
+
 Accessing legacy resources through sysfs
 ----------------------------------------
 
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index a2d85f6..e4d2c0d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -219,6 +219,35 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
 	return count;
 }
 
+#ifdef CONFIG_HOTPLUG
+static void remove_callback(void *data)
+{
+	struct pci_dev *pdev = (struct pci_dev *)data;
+	pci_remove_bus_device(pdev);
+	pci_dev_put(pdev);
+}
+
+static ssize_t
+remove_store(struct device *dev, struct device_attribute *dummy,
+	     const char *buf, size_t count)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	unsigned long val;
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (val)
+		sysfs_schedule_callback(&dev->kobj, remove_callback, pdev,
+		                        THIS_MODULE);
+
+	return count;
+}
+#endif
+
 struct device_attribute pci_dev_attrs[] = {
 	__ATTR_RO(resource),
 	__ATTR_RO(vendor),
@@ -237,6 +266,9 @@ struct device_attribute pci_dev_attrs[] = {
 	__ATTR(broken_parity_status,(S_IRUGO|S_IWUSR),
 		broken_parity_status_show,broken_parity_status_store),
 	__ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
+#ifdef CONFIG_HOTPLUG
+	__ATTR(remove, S_IWUSR, NULL, remove_store),
+#endif
 	__ATTR_NULL,
 };
 

[RFC PATCH v2 08/12] PCI: Introduce /sys/bus/pci/devices/.../rescan

[Alex Chiang]

This interface allows the user to force a rescan of the device's
parent bus and all subordinate buses, and rediscover devices removed
earlier from this part of the device tree.

Cc: Trent Piepho <xyzzy@speakeasy.org>
Cc: djwong@us.ibm.com
Reviewed-by: James Cameron <qz@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 Documentation/ABI/testing/sysfs-bus-pci |   10 ++++++++++
 drivers/pci/pci-sysfs.c                 |   20 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 8c0abc7..f59e963 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -15,6 +15,16 @@ Description:
 		hot-remove the PCI device and any of its children.
 		Depends on CONFIG_HOTPLUG.
 
+What:		/sys/bus/pci/devices/.../rescan
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		force a rescan of the device's parent bus and all
+		child buses, and re-discover devices removed earlier
+		from this part of the device tree.
+		Depends on CONFIG_HOTPLUG.
+
 What:		/sys/bus/pci/devices/.../vpd
 Date:		February 2008
 Contact:	Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index e4d2c0d..6e5f141 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -220,6 +220,25 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
 }
 
 #ifdef CONFIG_HOTPLUG
+static ssize_t
+dev_rescan_store(struct device *dev, struct device_attribute *attr,
+	      const char *buf, size_t count)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	unsigned long val;
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (val)
+		pci_do_scan_bus(pdev->bus);
+
+	return count;
+}
+
 static void remove_callback(void *data)
 {
 	struct pci_dev *pdev = (struct pci_dev *)data;
@@ -268,6 +287,7 @@ struct device_attribute pci_dev_attrs[] = {
 	__ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
 #ifdef CONFIG_HOTPLUG
 	__ATTR(remove, S_IWUSR, NULL, remove_store),
+	__ATTR(rescan, S_IWUSR, NULL, dev_rescan_store),
 #endif
 	__ATTR_NULL,
 };

[RFC PATCH v2 09/12] PCI Hotplug: restore fakephp interface with complete reimplementation

[Alex Chiang]

From: Trent Piepho <xyzzy@speakeasy.org>

A complete re-implementation of fakephp is necessary if it is to
present its former interface (pre-2.6.27, when it broke). The
reason is that PCI hotplug drivers call pci_hp_register(), which
enforces the rule that only one /sys/bus/pci/slots/ file may be
created per physical slot.

The change breaks the old fakephp's assumption that it could
create a file per function. So we re-implement fakephp to avoid
using the standard PCI hotplug API so that we can restore the old
fakephp user interface.

It puts entries in /sys/bus/pci/slots with the names of all PCI
devices/functions, exactly symmetrical to what is shown in
/sys/bus/pci/devices. Each slots/ entry has a "power" attribute,
which works the same way as the fakephp driver's power attribute
has worked.

There are a few improvements over old fakephp, which couldn't handle
PCI devices being added or removed via a means outside of
fakephp's knowledge.  If a device was added another way, old fakephp
didn't notice and didn't create the fake slot for it.  If a
device was removed another way, old fakephp didn't delete the fake
slot for it (and accessing the stale slot caused an oops).

The new implementation overcomes these limitations. As a
consequence, removing a bridge with other devices behind it now
works as well, which is something else old fakephp couldn't do
previously.

This duplicates a tiny bit of the code in the PCI core that does
this same function.  Re-using that code ends up being more
complex than duplicating it, and it makes code in the PCI core
more ugly just to support this legacy fakephp interface
compatibility layer.

[achiang@hp.com: rewrite changelog]
[achiang@hp.com: use pci_do_scan_bus()]
Reviewed-by: James Cameron <qz@hp.com>
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/hotplug/Makefile         |    2 
 drivers/pci/hotplug/fakephp.c        |  395 ----------------------------------
 drivers/pci/hotplug/legacy_fakephp.c |  162 ++++++++++++++
 3 files changed, 163 insertions(+), 396 deletions(-)
 delete mode 100644 drivers/pci/hotplug/fakephp.c
 create mode 100644 drivers/pci/hotplug/legacy_fakephp.c

diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
index 2aa117c..3314fe8 100644
--- a/drivers/pci/hotplug/Makefile
+++ b/drivers/pci/hotplug/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR)	+= rpadlpar_io.o
 obj-$(CONFIG_HOTPLUG_PCI_SGI)		+= sgi_hotplug.o
 
 # Link this last so it doesn't claim devices that have a real hotplug driver
-obj-$(CONFIG_HOTPLUG_PCI_FAKE)		+= fakephp.o
+obj-$(CONFIG_HOTPLUG_PCI_FAKE)		+= legacy_fakephp.o
 
 pci_hotplug-objs	:=	pci_hotplug_core.o
 
diff --git a/drivers/pci/hotplug/fakephp.c b/drivers/pci/hotplug/fakephp.c
deleted file mode 100644
index d8649e1..0000000
--- a/drivers/pci/hotplug/fakephp.c
+++ /dev/null
@@ -1,395 +0,0 @@
-/*
- * Fake PCI Hot Plug Controller Driver
- *
- * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
- * Copyright (C) 2003 IBM Corp.
- * Copyright (C) 2003 Rolf Eike Beer <eike-kernel@sf-tec.de>
- *
- * Based on ideas and code from:
- * 	Vladimir Kondratiev <vladimir.kondratiev@intel.com>
- *	Rolf Eike Beer <eike-kernel@sf-tec.de>
- *
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 2 of the License.
- *
- * Send feedback to <greg@kroah.com>
- */
-
-/*
- *
- * This driver will "emulate" removing PCI devices from the system.  If
- * the "power" file is written to with "0" then the specified PCI device
- * will be completely removed from the kernel.
- *
- * WARNING, this does NOT turn off the power to the PCI device.  This is
- * a "logical" removal, not a physical or electrical removal.
- *
- * Use this module at your own risk, you have been warned!
- *
- * Enabling PCI devices is left as an exercise for the reader...
- *
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/pci.h>
-#include <linux/pci_hotplug.h>
-#include <linux/init.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/workqueue.h>
-#include "../pci.h"
-
-#if !defined(MODULE)
-	#define MY_NAME	"fakephp"
-#else
-	#define MY_NAME	THIS_MODULE->name
-#endif
-
-#define dbg(format, arg...)					\
-	do {							\
-		if (debug)					\
-			printk(KERN_DEBUG "%s: " format,	\
-				MY_NAME , ## arg); 		\
-	} while (0)
-#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME , ## arg)
-#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME , ## arg)
-
-#define DRIVER_AUTHOR	"Greg Kroah-Hartman <greg@kroah.com>"
-#define DRIVER_DESC	"Fake PCI Hot Plug Controller Driver"
-
-struct dummy_slot {
-	struct list_head node;
-	struct hotplug_slot *slot;
-	struct pci_dev *dev;
-	struct work_struct remove_work;
-	unsigned long removed;
-};
-
-static int debug;
-static int dup_slots;
-static LIST_HEAD(slot_list);
-static struct workqueue_struct *dummyphp_wq;
-
-static void pci_rescan_worker(struct work_struct *work);
-static DECLARE_WORK(pci_rescan_work, pci_rescan_worker);
-
-static int enable_slot (struct hotplug_slot *slot);
-static int disable_slot (struct hotplug_slot *slot);
-
-static struct hotplug_slot_ops dummy_hotplug_slot_ops = {
-	.owner			= THIS_MODULE,
-	.enable_slot		= enable_slot,
-	.disable_slot		= disable_slot,
-};
-
-static void dummy_release(struct hotplug_slot *slot)
-{
-	struct dummy_slot *dslot = slot->private;
-
-	list_del(&dslot->node);
-	kfree(dslot->slot->info);
-	kfree(dslot->slot);
-	pci_dev_put(dslot->dev);
-	kfree(dslot);
-}
-
-#define SLOT_NAME_SIZE	8
-
-static int add_slot(struct pci_dev *dev)
-{
-	struct dummy_slot *dslot;
-	struct hotplug_slot *slot;
-	char name[SLOT_NAME_SIZE];
-	int retval = -ENOMEM;
-	static int count = 1;
-
-	slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
-	if (!slot)
-		goto error;
-
-	slot->info = kzalloc(sizeof(struct hotplug_slot_info), GFP_KERNEL);
-	if (!slot->info)
-		goto error_slot;
-
-	slot->info->power_status = 1;
-	slot->info->max_bus_speed = PCI_SPEED_UNKNOWN;
-	slot->info->cur_bus_speed = PCI_SPEED_UNKNOWN;
-
-	dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL);
-	if (!dslot)
-		goto error_info;
-
-	if (dup_slots)
-		snprintf(name, SLOT_NAME_SIZE, "fake");
-	else
-		snprintf(name, SLOT_NAME_SIZE, "fake%d", count++);
-	dbg("slot->name = %s\n", name);
-	slot->ops = &dummy_hotplug_slot_ops;
-	slot->release = &dummy_release;
-	slot->private = dslot;
-
-	retval = pci_hp_register(slot, dev->bus, PCI_SLOT(dev->devfn), name);
-	if (retval) {
-		err("pci_hp_register failed with error %d\n", retval);
-		goto error_dslot;
-	}
-
-	dbg("slot->name = %s\n", hotplug_slot_name(slot));
-	dslot->slot = slot;
-	dslot->dev = pci_dev_get(dev);
-	list_add (&dslot->node, &slot_list);
-	return retval;
-
-error_dslot:
-	kfree(dslot);
-error_info:
-	kfree(slot->info);
-error_slot:
-	kfree(slot);
-error:
-	return retval;
-}
-
-static int __init pci_scan_buses(void)
-{
-	struct pci_dev *dev = NULL;
-	int lastslot = 0;
-
-	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
-		if (PCI_FUNC(dev->devfn) > 0 &&
-				lastslot == PCI_SLOT(dev->devfn))
-			continue;
-		lastslot = PCI_SLOT(dev->devfn);
-		add_slot(dev);
-	}
-
-	return 0;
-}
-
-static void remove_slot(struct dummy_slot *dslot)
-{
-	int retval;
-
-	dbg("removing slot %s\n", hotplug_slot_name(dslot->slot));
-	retval = pci_hp_deregister(dslot->slot);
-	if (retval)
-		err("Problem unregistering a slot %s\n",
-			hotplug_slot_name(dslot->slot));
-}
-
-/* called from the single-threaded workqueue handler to remove a slot */
-static void remove_slot_worker(struct work_struct *work)
-{
-	struct dummy_slot *dslot =
-		container_of(work, struct dummy_slot, remove_work);
-	remove_slot(dslot);
-}
-
-/**
- * pci_rescan_slot - Rescan slot
- * @temp: Device template. Should be set: bus and devfn.
- *
- * Tries hard not to re-enable already existing devices;
- * also handles scanning of subfunctions.
- */
-static int pci_rescan_slot(struct pci_dev *temp)
-{
-	struct pci_bus *bus = temp->bus;
-	struct pci_dev *dev;
-	int func;
-	u8 hdr_type;
-	int count = 0;
-
-	if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
-		temp->hdr_type = hdr_type & 0x7f;
-		if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
-			pci_dev_put(dev);
-		else {
-			dev = pci_scan_single_device(bus, temp->devfn);
-			if (dev) {
-				dbg("New device on %s function %x:%x\n",
-					bus->name, temp->devfn >> 3,
-					temp->devfn & 7);
-				count++;
-			}
-		}
-		/* multifunction device? */
-		if (!(hdr_type & 0x80))
-			return count;
-
-		/* continue scanning for other functions */
-		for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
-			if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
-				continue;
-			temp->hdr_type = hdr_type & 0x7f;
-
-			if ((dev = pci_get_slot(bus, temp->devfn)) != NULL)
-				pci_dev_put(dev);
-			else {
-				dev = pci_scan_single_device(bus, temp->devfn);
-				if (dev) {
-					dbg("New device on %s function %x:%x\n",
-						bus->name, temp->devfn >> 3,
-						temp->devfn & 7);
-					count++;
-				}
-			}
-		}
-	}
-
-	return count;
-}
-
-
-/**
- * pci_rescan_bus - Rescan PCI bus
- * @bus: the PCI bus to rescan
- *
- * Call pci_rescan_slot for each possible function of the bus.
- */
-static void pci_rescan_bus(const struct pci_bus *bus)
-{
-	unsigned int devfn;
-	struct pci_dev *dev;
-	int retval;
-	int found = 0;
-	dev = alloc_pci_dev();
-	if (!dev)
-		return;
-
-	dev->bus = (struct pci_bus*)bus;
-	dev->sysdata = bus->sysdata;
-	for (devfn = 0; devfn < 0x100; devfn += 8) {
-		dev->devfn = devfn;
-		found += pci_rescan_slot(dev);
-	}
-
-	if (found) {
-		pci_bus_assign_resources(bus);
-		list_for_each_entry(dev, &bus->devices, bus_list) {
-			/* Skip already-added devices */
-			if (dev->is_added)
-					continue;
-			retval = pci_bus_add_device(dev);
-			if (retval)
-				dev_err(&dev->dev,
-					"Error adding device, continuing\n");
-			else
-				add_slot(dev);
-		}
-		pci_bus_add_devices(bus);
-	}
-	kfree(dev);
-}
-
-/* recursively scan all buses */
-static void pci_rescan_buses(const struct list_head *list)
-{
-	const struct list_head *l;
-	list_for_each(l,list) {
-		const struct pci_bus *b = pci_bus_b(l);
-		pci_rescan_bus(b);
-		pci_rescan_buses(&b->children);
-	}
-}
-
-/* initiate rescan of all pci buses */
-static inline void pci_rescan(void) {
-	pci_rescan_buses(&pci_root_buses);
-}
-
-/* called from the single-threaded workqueue handler to rescan all pci buses */
-static void pci_rescan_worker(struct work_struct *work)
-{
-	pci_rescan();
-}
-
-static int enable_slot(struct hotplug_slot *hotplug_slot)
-{
-	/* mis-use enable_slot for rescanning of the pci bus */
-	cancel_work_sync(&pci_rescan_work);
-	queue_work(dummyphp_wq, &pci_rescan_work);
-	return 0;
-}
-
-static int disable_slot(struct hotplug_slot *slot)
-{
-	struct dummy_slot *dslot;
-	struct pci_dev *dev;
-	int func;
-
-	if (!slot)
-		return -ENODEV;
-	dslot = slot->private;
-
-	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot_name(slot));
-
-	for (func = 7; func >= 0; func--) {
-		dev = pci_get_slot(dslot->dev->bus, dslot->dev->devfn + func);
-		if (!dev)
-			continue;
-
-		if (test_and_set_bit(0, &dslot->removed)) {
-			dbg("Slot already scheduled for removal\n");
-			pci_dev_put(dev);
-			return -ENODEV;
-		}
-
-		/* remove the device from the pci core */
-		pci_remove_bus_device(dev);
-
-		/* queue work item to blow away this sysfs entry and other
-		 * parts.
-		 */
-		INIT_WORK(&dslot->remove_work, remove_slot_worker);
-		queue_work(dummyphp_wq, &dslot->remove_work);
-
-		pci_dev_put(dev);
-	}
-	return 0;
-}
-
-static void cleanup_slots (void)
-{
-	struct list_head *tmp;
-	struct list_head *next;
-	struct dummy_slot *dslot;
-
-	destroy_workqueue(dummyphp_wq);
-	list_for_each_safe (tmp, next, &slot_list) {
-		dslot = list_entry (tmp, struct dummy_slot, node);
-		remove_slot(dslot);
-	}
-	
-}
-
-static int __init dummyphp_init(void)
-{
-	info(DRIVER_DESC "\n");
-
-	dummyphp_wq = create_singlethread_workqueue(MY_NAME);
-	if (!dummyphp_wq)
-		return -ENOMEM;
-
-	return pci_scan_buses();
-}
-
-
-static void __exit dummyphp_exit(void)
-{
-	cleanup_slots();
-}
-
-module_init(dummyphp_init);
-module_exit(dummyphp_exit);
-
-MODULE_AUTHOR(DRIVER_AUTHOR);
-MODULE_DESCRIPTION(DRIVER_DESC);
-MODULE_LICENSE("GPL");
-module_param(debug, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
-module_param(dup_slots, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(dup_slots, "Force duplicate slot names for debugging");
diff --git a/drivers/pci/hotplug/legacy_fakephp.c b/drivers/pci/hotplug/legacy_fakephp.c
new file mode 100644
index 0000000..e75af9e
--- /dev/null
+++ b/drivers/pci/hotplug/legacy_fakephp.c
@@ -0,0 +1,162 @@
+/* Works like the fakephp driver used to, except a little better.
+ *
+ * - It's possible to remove devices with subordinate busses.
+ * - New PCI devices that appear via any method, not just a fakephp triggered
+ *   rescan, will be noticed.
+ * - Devices that are removed via any method, not just a fakephp triggered
+ *   removal, will also be noticed.
+ *
+ * Uses nothing from the pci-hotplug subsystem.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include "../pci.h"
+
+struct legacy_slot {
+	struct kobject		kobj;
+	struct pci_dev		*dev;
+	struct list_head	list;
+};
+
+static LIST_HEAD(legacy_list);
+
+static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr,
+			   char *buf)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+	strcpy(buf, "1\n");
+	return 2;
+}
+
+static void remove_callback(void *data)
+{
+	pci_remove_bus_device((struct pci_dev *)data);
+}
+
+static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr,
+			    const char *buf, size_t len)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+	unsigned long val;
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val)
+		pci_do_scan_bus(slot->dev->bus);
+	else
+		sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback,
+		                        slot->dev, THIS_MODULE);
+	return len;
+}
+
+static struct attribute *legacy_attrs[] = {
+	&(struct attribute){ .name = "power", .mode = 0644 },
+	NULL,
+};
+
+static void legacy_release(struct kobject *kobj)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+
+	pci_dev_put(slot->dev);
+	kfree(slot);
+}
+
+static struct kobj_type legacy_ktype = {
+	.sysfs_ops = &(struct sysfs_ops){
+		.store = legacy_store, .show = legacy_show
+	},
+	.release = &legacy_release,
+	.default_attrs = legacy_attrs,
+};
+
+static int legacy_add_slot(struct pci_dev *pdev)
+{
+	struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL);
+
+	if (!slot)
+		return -ENOMEM;
+
+	if (kobject_init_and_add(&slot->kobj, &legacy_ktype,
+				 &pci_slots_kset->kobj, "%s",
+				 pdev->dev.bus_id)) {
+		dev_warn(&pdev->dev, "Failed to created legacy fake slot\n");
+		return -EINVAL;
+	}
+	slot->dev = pci_dev_get(pdev);
+
+	list_add(&slot->list, &legacy_list);
+
+	return 0;
+}
+
+static int legacy_notify(struct notifier_block *nb,
+			 unsigned long action, void *data)
+{
+        struct pci_dev *pdev = to_pci_dev(data);
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		legacy_add_slot(pdev);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		struct legacy_slot *slot;
+
+		list_for_each_entry(slot, &legacy_list, list)
+			if (slot->dev == pdev)
+				goto found;
+
+		dev_warn(&pdev->dev, "Missing legacy fake slot?");
+		return -ENODEV;
+found:
+		kobject_del(&slot->kobj);
+		list_del(&slot->list);
+		kobject_put(&slot->kobj);
+	}
+
+	return 0;
+}
+
+static struct notifier_block legacy_notifier = {
+	.notifier_call = legacy_notify
+};
+
+static int __init init_legacy(void)
+{
+	struct pci_dev *pdev = NULL;
+
+	/* Add existing devices */
+	while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev)))
+		legacy_add_slot(pdev);
+
+	/* Be alerted of any new ones */
+	bus_register_notifier(&pci_bus_type, &legacy_notifier);
+	return 0;
+}
+module_init(init_legacy);
+
+static void __exit remove_legacy(void)
+{
+	struct legacy_slot *slot, *tmp;
+
+	bus_unregister_notifier(&pci_bus_type, &legacy_notifier);
+
+	list_for_each_entry_safe(slot, tmp, &legacy_list, list) {
+		list_del(&slot->list);
+		kobject_del(&slot->kobj);
+		kobject_put(&slot->kobj);
+	}
+}
+module_exit(remove_legacy);
+
+
+MODULE_AUTHOR("Trent Piepho <xyzzy@speakeasy.org>");
+MODULE_DESCRIPTION("Legacy version of the fakephp interface");
+MODULE_LICENSE("GPL");

[RFC PATCH v2 10/12] PCI Hotplug: rename legacy_fakephp to fakephp

[Alex Chiang]

We wanted to replace fakephp wholesale, so rename legacy_fakephp back
to fakephp. Yes, this is a silly commit, but it produces a much easier
patch to read and review.

Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/hotplug/Makefile         |    2 
 drivers/pci/hotplug/fakephp.c        |  162 ++++++++++++++++++++++++++++++++++
 drivers/pci/hotplug/legacy_fakephp.c |  162 ----------------------------------
 3 files changed, 163 insertions(+), 163 deletions(-)
 create mode 100644 drivers/pci/hotplug/fakephp.c
 delete mode 100644 drivers/pci/hotplug/legacy_fakephp.c

diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
index 3314fe8..2aa117c 100644
--- a/drivers/pci/hotplug/Makefile
+++ b/drivers/pci/hotplug/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR)	+= rpadlpar_io.o
 obj-$(CONFIG_HOTPLUG_PCI_SGI)		+= sgi_hotplug.o
 
 # Link this last so it doesn't claim devices that have a real hotplug driver
-obj-$(CONFIG_HOTPLUG_PCI_FAKE)		+= legacy_fakephp.o
+obj-$(CONFIG_HOTPLUG_PCI_FAKE)		+= fakephp.o
 
 pci_hotplug-objs	:=	pci_hotplug_core.o
 
diff --git a/drivers/pci/hotplug/fakephp.c b/drivers/pci/hotplug/fakephp.c
new file mode 100644
index 0000000..e75af9e
--- /dev/null
+++ b/drivers/pci/hotplug/fakephp.c
@@ -0,0 +1,162 @@
+/* Works like the fakephp driver used to, except a little better.
+ *
+ * - It's possible to remove devices with subordinate busses.
+ * - New PCI devices that appear via any method, not just a fakephp triggered
+ *   rescan, will be noticed.
+ * - Devices that are removed via any method, not just a fakephp triggered
+ *   removal, will also be noticed.
+ *
+ * Uses nothing from the pci-hotplug subsystem.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include "../pci.h"
+
+struct legacy_slot {
+	struct kobject		kobj;
+	struct pci_dev		*dev;
+	struct list_head	list;
+};
+
+static LIST_HEAD(legacy_list);
+
+static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr,
+			   char *buf)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+	strcpy(buf, "1\n");
+	return 2;
+}
+
+static void remove_callback(void *data)
+{
+	pci_remove_bus_device((struct pci_dev *)data);
+}
+
+static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr,
+			    const char *buf, size_t len)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+	unsigned long val;
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val)
+		pci_do_scan_bus(slot->dev->bus);
+	else
+		sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback,
+		                        slot->dev, THIS_MODULE);
+	return len;
+}
+
+static struct attribute *legacy_attrs[] = {
+	&(struct attribute){ .name = "power", .mode = 0644 },
+	NULL,
+};
+
+static void legacy_release(struct kobject *kobj)
+{
+	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
+
+	pci_dev_put(slot->dev);
+	kfree(slot);
+}
+
+static struct kobj_type legacy_ktype = {
+	.sysfs_ops = &(struct sysfs_ops){
+		.store = legacy_store, .show = legacy_show
+	},
+	.release = &legacy_release,
+	.default_attrs = legacy_attrs,
+};
+
+static int legacy_add_slot(struct pci_dev *pdev)
+{
+	struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL);
+
+	if (!slot)
+		return -ENOMEM;
+
+	if (kobject_init_and_add(&slot->kobj, &legacy_ktype,
+				 &pci_slots_kset->kobj, "%s",
+				 pdev->dev.bus_id)) {
+		dev_warn(&pdev->dev, "Failed to created legacy fake slot\n");
+		return -EINVAL;
+	}
+	slot->dev = pci_dev_get(pdev);
+
+	list_add(&slot->list, &legacy_list);
+
+	return 0;
+}
+
+static int legacy_notify(struct notifier_block *nb,
+			 unsigned long action, void *data)
+{
+        struct pci_dev *pdev = to_pci_dev(data);
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		legacy_add_slot(pdev);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		struct legacy_slot *slot;
+
+		list_for_each_entry(slot, &legacy_list, list)
+			if (slot->dev == pdev)
+				goto found;
+
+		dev_warn(&pdev->dev, "Missing legacy fake slot?");
+		return -ENODEV;
+found:
+		kobject_del(&slot->kobj);
+		list_del(&slot->list);
+		kobject_put(&slot->kobj);
+	}
+
+	return 0;
+}
+
+static struct notifier_block legacy_notifier = {
+	.notifier_call = legacy_notify
+};
+
+static int __init init_legacy(void)
+{
+	struct pci_dev *pdev = NULL;
+
+	/* Add existing devices */
+	while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev)))
+		legacy_add_slot(pdev);
+
+	/* Be alerted of any new ones */
+	bus_register_notifier(&pci_bus_type, &legacy_notifier);
+	return 0;
+}
+module_init(init_legacy);
+
+static void __exit remove_legacy(void)
+{
+	struct legacy_slot *slot, *tmp;
+
+	bus_unregister_notifier(&pci_bus_type, &legacy_notifier);
+
+	list_for_each_entry_safe(slot, tmp, &legacy_list, list) {
+		list_del(&slot->list);
+		kobject_del(&slot->kobj);
+		kobject_put(&slot->kobj);
+	}
+}
+module_exit(remove_legacy);
+
+
+MODULE_AUTHOR("Trent Piepho <xyzzy@speakeasy.org>");
+MODULE_DESCRIPTION("Legacy version of the fakephp interface");
+MODULE_LICENSE("GPL");
diff --git a/drivers/pci/hotplug/legacy_fakephp.c b/drivers/pci/hotplug/legacy_fakephp.c
deleted file mode 100644
index e75af9e..0000000
--- a/drivers/pci/hotplug/legacy_fakephp.c
+++ /dev/null
@@ -1,162 +0,0 @@
-/* Works like the fakephp driver used to, except a little better.
- *
- * - It's possible to remove devices with subordinate busses.
- * - New PCI devices that appear via any method, not just a fakephp triggered
- *   rescan, will be noticed.
- * - Devices that are removed via any method, not just a fakephp triggered
- *   removal, will also be noticed.
- *
- * Uses nothing from the pci-hotplug subsystem.
- *
- */
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/list.h>
-#include <linux/kobject.h>
-#include <linux/sysfs.h>
-#include <linux/init.h>
-#include <linux/pci.h>
-#include "../pci.h"
-
-struct legacy_slot {
-	struct kobject		kobj;
-	struct pci_dev		*dev;
-	struct list_head	list;
-};
-
-static LIST_HEAD(legacy_list);
-
-static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr,
-			   char *buf)
-{
-	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
-	strcpy(buf, "1\n");
-	return 2;
-}
-
-static void remove_callback(void *data)
-{
-	pci_remove_bus_device((struct pci_dev *)data);
-}
-
-static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr,
-			    const char *buf, size_t len)
-{
-	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
-	unsigned long val;
-
-	if (strict_strtoul(buf, 0, &val) < 0)
-		return -EINVAL;
-
-	if (val)
-		pci_do_scan_bus(slot->dev->bus);
-	else
-		sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback,
-		                        slot->dev, THIS_MODULE);
-	return len;
-}
-
-static struct attribute *legacy_attrs[] = {
-	&(struct attribute){ .name = "power", .mode = 0644 },
-	NULL,
-};
-
-static void legacy_release(struct kobject *kobj)
-{
-	struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
-
-	pci_dev_put(slot->dev);
-	kfree(slot);
-}
-
-static struct kobj_type legacy_ktype = {
-	.sysfs_ops = &(struct sysfs_ops){
-		.store = legacy_store, .show = legacy_show
-	},
-	.release = &legacy_release,
-	.default_attrs = legacy_attrs,
-};
-
-static int legacy_add_slot(struct pci_dev *pdev)
-{
-	struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL);
-
-	if (!slot)
-		return -ENOMEM;
-
-	if (kobject_init_and_add(&slot->kobj, &legacy_ktype,
-				 &pci_slots_kset->kobj, "%s",
-				 pdev->dev.bus_id)) {
-		dev_warn(&pdev->dev, "Failed to created legacy fake slot\n");
-		return -EINVAL;
-	}
-	slot->dev = pci_dev_get(pdev);
-
-	list_add(&slot->list, &legacy_list);
-
-	return 0;
-}
-
-static int legacy_notify(struct notifier_block *nb,
-			 unsigned long action, void *data)
-{
-        struct pci_dev *pdev = to_pci_dev(data);
-
-	if (action == BUS_NOTIFY_ADD_DEVICE) {
-		legacy_add_slot(pdev);
-	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
-		struct legacy_slot *slot;
-
-		list_for_each_entry(slot, &legacy_list, list)
-			if (slot->dev == pdev)
-				goto found;
-
-		dev_warn(&pdev->dev, "Missing legacy fake slot?");
-		return -ENODEV;
-found:
-		kobject_del(&slot->kobj);
-		list_del(&slot->list);
-		kobject_put(&slot->kobj);
-	}
-
-	return 0;
-}
-
-static struct notifier_block legacy_notifier = {
-	.notifier_call = legacy_notify
-};
-
-static int __init init_legacy(void)
-{
-	struct pci_dev *pdev = NULL;
-
-	/* Add existing devices */
-	while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev)))
-		legacy_add_slot(pdev);
-
-	/* Be alerted of any new ones */
-	bus_register_notifier(&pci_bus_type, &legacy_notifier);
-	return 0;
-}
-module_init(init_legacy);
-
-static void __exit remove_legacy(void)
-{
-	struct legacy_slot *slot, *tmp;
-
-	bus_unregister_notifier(&pci_bus_type, &legacy_notifier);
-
-	list_for_each_entry_safe(slot, tmp, &legacy_list, list) {
-		list_del(&slot->list);
-		kobject_del(&slot->kobj);
-		kobject_put(&slot->kobj);
-	}
-}
-module_exit(remove_legacy);
-
-
-MODULE_AUTHOR("Trent Piepho <xyzzy@speakeasy.org>");
-MODULE_DESCRIPTION("Legacy version of the fakephp interface");
-MODULE_LICENSE("GPL");

[RFC PATCH v2 11/12] PCI Hotplug: schedule fakephp for feature removal

[Alex Chiang]

Now that the PCI core is capable of function-level remove and rescan
as well as bus-level rescan, there's no functional need to keep fakephp
anymore.

We keep it around for userspace compatibility reasons, schedule removal
in three years.

Signed-off-by: Alex Chiang <achiang@hp.com>
---

 Documentation/feature-removal-schedule.txt |   32 ++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 5ddbe35..fc3505b 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -335,3 +335,35 @@ Why:	In 2.6.18 the Secmark concept was introduced to replace the "compat_net"
 	Secmark, it is time to deprecate the older mechanism and start the
 	process of removing the old code.
 Who:	Paul Moore <paul.moore@hp.com>
+
+---------------------------
+
+What:	fakephp and associated sysfs files in /sys/bus/pci/slots/
+When:	2011
+Why:	In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
+	represent a machine's physical PCI slots. The change in semantics
+	had userspace implications, as the hotplug core no longer allowed
+	drivers to create multiple sysfs files per physical slot (required
+	for multi-function devices, e.g.). fakephp was seen as a developer's
+	tool only, and its interface changed. Too late, we learned that
+	there were some users of the fakephp interface.
+
+	In 2.6.30, the original fakephp interface was restored. At the same
+	time, the PCI core gained the ability that fakephp provided, namely
+	function-level hot-remove and hot-add.
+
+	Since the PCI core now provides the same functionality, exposed in:
+
+		/sys/bus/pci/rescan
+		/sys/bus/pci/devices/.../remove
+		/sys/bus/pci/devices/.../rescan
+
+	there is no functional reason to maintain fakephp as well.
+
+	We will keep the existing module so that 'modprobe fakephp' will
+	present the old /sys/bus/pci/slots/... interface for compatibility,
+	but users are urged to migrate their applications to the API above.
+
+	After a reasonable transition period, we will remove the legacy
+	fakephp interface.
+Who:	Alex Chiang <achiang@hp.com>

[RFC PATCH v2 12/12] PCI: more whitespace cleanups

[Alex Chiang]

Clean up some stray whitespace issues.

Signed-off-by: Alex Chiang <achiang@hp.com>
---

 drivers/pci/pci-sysfs.c |   18 +++++++++---------
 drivers/pci/probe.c     |   16 +++++++++-------
 drivers/pci/remove.c    |    4 ++--
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 6e5f141..42121ec 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -10,7 +10,7 @@
  *
  * File attributes for PCI devices
  *
- * Modeled after usb's driverfs.c 
+ * Modeled after usb's driverfs.c
  *
  */
 
@@ -70,7 +70,7 @@ static ssize_t broken_parity_status_store(struct device *dev,
 
 static ssize_t local_cpus_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
-{		
+{
 	const struct cpumask *mask;
 	int len;
 
@@ -380,13 +380,13 @@ pci_write_config(struct kobject *kobj, struct bin_attribute *bin_attr,
 		size = dev->cfg_size - off;
 		count = size;
 	}
-	
+
 	if ((off & 1) && size) {
 		pci_user_write_config_byte(dev, off, data[off - init_off]);
 		off++;
 		size--;
 	}
-	
+
 	if ((off & 3) && size > 2) {
 		u16 val = data[off - init_off];
 		val |= (u16) data[off - init_off + 1] << 8;
@@ -404,7 +404,7 @@ pci_write_config(struct kobject *kobj, struct bin_attribute *bin_attr,
 		off += 4;
 		size -= 4;
 	}
-	
+
 	if (size >= 2) {
 		u16 val = data[off - init_off];
 		val |= (u16) data[off - init_off + 1] << 8;
@@ -818,21 +818,21 @@ pci_read_rom(struct kobject *kobj, struct bin_attribute *bin_attr,
 
 	if (!pdev->rom_attr_enabled)
 		return -EINVAL;
-	
+
 	rom = pci_map_rom(pdev, &size);	/* size starts out as PCI window size */
 	if (!rom)
 		return 0;
-		
+
 	if (off >= size)
 		count = 0;
 	else {
 		if (off + count > size)
 			count = size - off;
-		
+
 		memcpy_fromio(buf, rom + off, count);
 	}
 	pci_unmap_rom(pdev, rom);
-		
+
 	return count;
 }
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d2bd1b0..d853abe 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -494,7 +494,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 	}
 
 	/* Disable MasterAbortMode during probing to avoid reporting
-	   of bus errors (in some architectures) */ 
+	   of bus errors (in some architectures) */
 	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
 	pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
 			      bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);
@@ -570,7 +570,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 			buses &= ~0xff000000;
 			buses |= CARDBUS_LATENCY_TIMER << 24;
 		}
-			
+
 		/*
 		 * We need to blast all three values with a single write.
 		 */
@@ -680,7 +680,7 @@ static void pci_read_irq(struct pci_dev *dev)
  * pci_setup_device - fill in class and map information of a device
  * @dev: the device structure to fill
  *
- * Initialize the device structure with information about the device's 
+ * Initialize the device structure with information about the device's
  * vendor,class,memory and IO-space addresses,IRQ lines etc.
  * Called at initialisation of the PCI subsystem and by CardBus services.
  * Returns 0 on success and -1 if unknown type of device (not normal, bridge
@@ -720,8 +720,8 @@ static int pci_setup_device(struct pci_dev * dev)
 		pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device);
 
 		/*
-		 *	Do the ugly legacy mode stuff here rather than broken chip
-		 *	quirk code. Legacy mode ATA controllers have fixed
+		 *	Do the ugly legacy mode stuff here rather than broken
+		 *	chip quirk code. Legacy mode ATA controllers have fixed
 		 *	addresses. These are not always echoed in BAR0-3, and
 		 *	BAR0-3 in a few cases contain junk!
 		 */
@@ -752,7 +752,7 @@ static int pci_setup_device(struct pci_dev * dev)
 			goto bad;
 		/* The PCI-to-PCI bridge spec requires that subtractive
 		   decoding (i.e. transparent) bridge must have programming
-		   interface code of 0x01. */ 
+		   interface code of 0x01. */
 		pci_read_irq(dev);
 		dev->transparent = ((dev->class & 0xff) == 1);
 		pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
@@ -1126,7 +1126,9 @@ struct pci_bus * pci_create_bus(struct device *parent,
 	b->ops = ops;
 
 	if (pci_find_bus(pci_domain_nr(b), bus)) {
-		/* If we already got to this bus through a different bridge, ignore it */
+		/* If we already got to this bus through a different bridge,
+		 * ignore it
+		 */
 		pr_debug("PCI: Bus %04x:%02x already known\n", pci_domain_nr(b), bus);
 		goto err_out;
 	}
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 042e089..ba58128 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -7,7 +7,7 @@ static void pci_free_resources(struct pci_dev *dev)
 {
 	int i;
 
- 	msi_remove_pci_irq_vectors(dev);
+	msi_remove_pci_irq_vectors(dev);
 
 	pci_cleanup_rom(dev);
 	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
@@ -49,7 +49,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
  * pci_remove_device_safe - remove an unused hotplug device
  * @dev: the device to remove
  *
- * Delete the device structure from the device lists and 
+ * Delete the device structure from the device lists and
  * notify userspace (/sbin/hotplug), but only if the device
  * in question is not being used by a driver.
  * Returns 0 on success.