Patch "PCI: Avoid bus reset if bridge itself is broken" has been added to the 3.18-stable tree

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This is a note to let you know that I've just added the patch titled

    PCI: Avoid bus reset if bridge itself is broken

to the 3.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-avoid-bus-reset-if-bridge-itself-is-broken.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From foo@baz Thu Dec 21 10:55:04 CET 2017
From: David Daney <david.daney@xxxxxxxxxx>
Date: Fri, 8 Sep 2017 10:10:31 +0200
Subject: PCI: Avoid bus reset if bridge itself is broken

From: David Daney <david.daney@xxxxxxxxxx>


[ Upstream commit 357027786f3523d26f42391aa4c075b8495e5d28 ]

When checking to see if a PCI bus can safely be reset, we previously
checked to see if any of the children had their PCI_DEV_FLAGS_NO_BUS_RESET
flag set.  Children marked with that flag are known not to behave well
after a bus reset.

Some PCIe root port bridges also do not behave well after a bus reset,
sometimes causing the devices behind the bridge to become unusable.

Add a check for PCI_DEV_FLAGS_NO_BUS_RESET being set in the bridge device
to allow these bridges to be flagged, and prevent their secondary buses
from being reset.

Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
[jglauber@xxxxxxxxxx: fixed typo]
Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx>

Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/pci/pci.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3580,6 +3580,10 @@ static bool pci_bus_resetable(struct pci
 {
 	struct pci_dev *dev;
 
+
+	if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
+		return false;
+
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
 		    (dev->subordinate && !pci_bus_resetable(dev->subordinate)))


Patches currently in stable-queue which might be from david.daney@xxxxxxxxxx are

queue-3.18/pci-avoid-bus-reset-if-bridge-itself-is-broken.patch



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