PCI: add rescan to /sys/.../pci_bus/.../

After remove the device from /sys, we have to rescan all or
find out the bridge and access /sys../device/rescan there.

this patch add /sys/.../pci_bus/.../rescan. So user can rescan more easy.
that is more clean and easy to understand.

like after remove 0000:c4:00.0, you can rescan 0000:c4 directly.

-v2: According to Jesse, use function instead of exposing attr, so could hide
	#ifdef in header file.
     also add code to remove rescan file in remove path.
-v3: GregKH pointed out that we should use dev_attrs to avoid racing.
     So add pcibus_attrs and make it to be member of pcibus_attrs.
-v4: Change name to pcibus_dev_attrs according to GregKH

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 36bf454ba85..349ecf26ce1 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -74,6 +74,15 @@ Description:
                 hot-remove the PCI device and any of its children.
                 Depends on CONFIG_HOTPLUG.
 
+What:           /sys/bus/pci/devices/.../pci_bus/.../rescan
+Date:           May 2011
+Contact:        Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+                Writing a non-zero value to this attribute will
+                force a rescan of the 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/.../rescan
 Date:           January 2009
 Contact:        Linux PCI developers <linux-pci@vger.kernel.org>