From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-sn1nam01on0094.outbound.protection.outlook.com ([104.47.32.94]:45235 "EHLO NAM01-SN1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1031889AbeCAPYV (ORCPT ); Thu, 1 Mar 2018 10:24:21 -0500 From: Sasha Levin To: "stable@vger.kernel.org" , "stable-commits@vger.kernel.org" CC: David Daney , Jan Glauber , Bjorn Helgaas , Sasha Levin Subject: [added to the 4.1 stable tree] PCI: Avoid bus reset if bridge itself is broken Date: Thu, 1 Mar 2018 15:22:55 +0000 Message-ID: <20180301152116.1486-47-alexander.levin@microsoft.com> References: <20180301152116.1486-1-alexander.levin@microsoft.com> In-Reply-To: <20180301152116.1486-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: David Daney This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ 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 [jglauber@cavium.com: fixed typo] Signed-off-by: Jan Glauber Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson Signed-off-by: Sasha Levin --- drivers/pci/pci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 409f895b5a3d..ffd8fe77b8ae 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3651,6 +3651,10 @@ static bool pci_bus_resetable(struct pci_bus *bus) { struct pci_dev *dev; =20 + + 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))) --=20 2.14.1