[PATCH] PCI: Only call pci_stop_bus_device() one time for children devices during removing

[PATCH] PCI: Only call pci_stop_bus_device() one time for children devices during removing

[Yinghai Lu]

During debugging pcie hotplug with SRIOV with pcie switch, found
pci_stop_bus_device() are called several times for some children devices.

Current pci_remove_bus_device() will call pci_stop_bus_device() at first.
and then use remove_behind_bridge() to call pci_stop_bus_device() for children
devices. But pci_stop_bus_device() already include depth first to stop children.
So We can remove unnecessary calling in pci_remove_behind_bridge() for children.

The patch change original pci_remove_bus_device() to __pci_remove_bus_device(), and
it only do remove work, and new pci_remove_bus_device will call
pci_stop_bus_device() one time, and then call __pci_remove_bus_device().

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/pci/remove.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/pci/remove.c
===================================================================
--- linux-2.6.orig/drivers/pci/remove.c
+++ linux-2.6/drivers/pci/remove.c
@@ -89,9 +89,8 @@ EXPORT_SYMBOL(pci_remove_bus);
  * device lists, remove the /proc entry, and notify userspace
  * (/sbin/hotplug).
  */
-void pci_remove_bus_device(struct pci_dev *dev)
+static void __pci_remove_bus_device(struct pci_dev *dev)
 {
-	pci_stop_bus_device(dev);
 	if (dev->subordinate) {
 		struct pci_bus *b = dev->subordinate;
 
@@ -102,6 +101,11 @@ void pci_remove_bus_device(struct pci_de
 
 	pci_destroy_dev(dev);
 }
+void pci_remove_bus_device(struct pci_dev *dev)
+{
+	pci_stop_bus_device(dev);
+	__pci_remove_bus_device(dev);
+}
 
 /**
  * pci_remove_behind_bridge - remove all devices behind a PCI bridge
@@ -117,7 +121,7 @@ void pci_remove_behind_bridge(struct pci
 
 	if (dev->subordinate)
 		list_for_each_safe(l, n, &dev->subordinate->devices)
-			pci_remove_bus_device(pci_dev_b(l));
+			__pci_remove_bus_device(pci_dev_b(l));
 }
 
 static void pci_stop_bus_devices(struct pci_bus *bus)

Re: [PATCH] PCI: Only call pci_stop_bus_device() one time for children devices during removing

[Jesse Barnes]

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On Tue, 22 Nov 2011 21:06:53 -0800
Yinghai Lu <yinghai.lu@oracle.com> wrote:

> 
> During debugging pcie hotplug with SRIOV with pcie switch, found
> pci_stop_bus_device() are called several times for some children devices.
> 
> Current pci_remove_bus_device() will call pci_stop_bus_device() at first.
> and then use remove_behind_bridge() to call pci_stop_bus_device() for children
> devices. But pci_stop_bus_device() already include depth first to stop children.
> So We can remove unnecessary calling in pci_remove_behind_bridge() for children.
> 
> The patch change original pci_remove_bus_device() to __pci_remove_bus_device(), and
> it only do remove work, and new pci_remove_bus_device will call
> pci_stop_bus_device() one time, and then call __pci_remove_bus_device().
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>

applied to linux-next, thanks.

-- 
Jesse Barnes, Intel Open Source Technology Center

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