On 2018-08-14 19:21, Thomas Tai wrote:
On 08/14/2018 05:22 AM, poza@xxxxxxxxxxxxxx wrote:
On 2018-08-14 14:46, poza@xxxxxxxxxxxxxx wrote:
On 2018-08-13 22:21, Thomas Tai wrote:
In order to prevent the pcie_do_fatal_recovery() from
using the device after it is removed, the device's
domain:bus:devfn is stored at the entry of
pcie_do_fatal_recovery(). After rescanning the bus, the
stored domain:bus:devfn is used to find the device and
uses to report pci_info. The original issue only happens
on an non-bridge device, a local variable is used instead
of checking the device's header type.
Signed-off-by: Thomas Tai <thomas.tai@xxxxxxxxxx>
---
drivers/pci/pcie/err.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index f02e334..3414445 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -287,15 +287,20 @@ void pcie_do_fatal_recovery(struct pci_dev
*dev,
u32 service)
struct pci_bus *parent;
struct pci_dev *pdev, *temp;
pci_ers_result_t result;
+ bool is_bridge_device = false;
+ u16 domain = pci_domain_nr(dev->bus);
+ u8 bus = dev->bus->number;
+ u8 devfn = dev->devfn;
- if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ is_bridge_device = true;
udev = dev;
- else
+ } else {
udev = dev->bus->self;
+ }
parent = udev->subordinate;
pci_lock_rescan_remove();
- pci_dev_get(dev);
list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
bus_list) {
pci_dev_get(pdev);
@@ -309,27 +314,35 @@ void pcie_do_fatal_recovery(struct pci_dev
*dev,
u32 service)
result = reset_link(udev, service);
- if ((service == PCIE_PORT_SERVICE_AER) &&
- (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
+ if (service == PCIE_PORT_SERVICE_AER && is_bridge_device) {
/*
* If the error is reported by a bridge, we think this
error
* is related to the downstream link of the bridge, so we
* do error recovery on all subordinates of the bridge
instead
* of the bridge and clear the error status of the bridge.
*/
- pci_cleanup_aer_uncorrect_error_status(dev);
+ pci_cleanup_aer_uncorrect_error_status(udev);
}
if (result == PCI_ERS_RESULT_RECOVERED) {
if (pcie_wait_for_link(udev, true))
pci_rescan_bus(udev->bus);
- pci_info(dev, "Device recovery from fatal error
successful\n");
+ /* find the pci_dev after rescanning the bus */
+ dev = pci_get_domain_bus_and_slot(domain, bus, devfn);
one of the motivations was to remove and re-enumerate rather then
going thorugh driver's recovery sequence
was; it might be possible that hotplug capable bridge, the device
might have changed.
hence this check will fail
Thanks Oza for your information. Instead of searching for the dev_pci,
should I just use the stored domain:bus:devfn to printout the info?
+ if (dev)
+ pci_info(dev, "Device recovery from fatal error
successful\n");
+ else
+ pr_err("AER: Can not find pci_dev for
%04x:%02x:%02x.%x\n",
+ domain, bus,
+ PCI_SLOT(devfn), PCI_FUNC(devfn));
+ pci_dev_put(dev);
That is, replace above with:
pr_info("AER: Device %04x:%02x:%02x.%x recover from fatal error
successful\n", domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
is this not sufficient to print ? which is there already.
pci_info(dev, "Device recovery from fatal error successful\n");
} else {
- pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
- pci_info(dev, "Device recovery from fatal error failed\n");
+ if (is_bridge_device)
previously there was no condition.. why is this required now ?
and it was doing on "dev" while you are doing it on "udev"
is that the reason we dont watnt o use dev after it is removed ?
instead do pci_uevent_ers on bridge ?
Yes, that's exactly the reason. I should have written down the reason
in the commit log. Here is the details explanation for the benefit of
others. If the failing device is a bridge device, udev is equal to
dev. So we can use udev in the pci_uevent_ers. But for non bridge
device the device is already removed from the bus and thus can't send
pci_uevent_ers.
Thank you,
Thomas
+ pci_uevent_ers(udev, PCI_ERS_RESULT_DISCONNECT);
+ pr_err("AER: Device %04x:%02x:%02x.%x recovery from fatal
error failed\n",
+ domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
}
- pci_dev_put(dev);
pci_unlock_rescan_remove();
}
Regards,
Oza.
