[PATCH] PCI: Fix hotplug remove with sriov again

[Yinghai Lu <yinghai@kernel.org>]

Found hot-remove pcie card with sriov enabled cause crash in v3.10.

It is regression caused by commit ba518e3c177547dfebf7fa7252cea0c850e7ce25
(PCI: pciehp: Iterate over all devices in slot, not functions 0-7)

That commit change to use bus->devices to iterate devices under
bus to run pci_stop_and_remove_bus_device().
Actually it duplicates the problem with those bus->devices iteratation
that we try to fix in commit ac205b7bb72fa4227d2e79979bbe2b4687cdf44d
(PCI: make sriov work with hotplug remove)

Change to iterate reversely as we did last time.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: <stable@vger.kernel.org> v3.9+

---
 drivers/pci/hotplug/pciehp_pci.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Index: linux-2.6/drivers/pci/hotplug/pciehp_pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/hotplug/pciehp_pci.c
+++ linux-2.6/drivers/pci/hotplug/pciehp_pci.c
@@ -92,7 +92,13 @@ int pciehp_unconfigure_device(struct slo
 	if (ret)
 		presence = 0;
 
-	list_for_each_entry_safe(dev, temp, &parent->devices, bus_list) {
+	/*
+	 * Need to iterate device reversely, as during
+	 * stop PF driver, VF will be removed, the list_for_each
+	 * could point to removed VF with temp.
+	 */
+	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
+					 bus_list) {
 		pci_dev_get(dev);
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
 			pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);