Re: [External] Re: [PATCH 2/3] PCI/ERR: Clear fatal status in pcie_do_recovery()
From: Zhuo Chen
Date: Tue Sep 27 2022 - 09:41:28 EST
On 9/27/22 2:09 AM, Bjorn Helgaas wrote:
On Mon, Sep 26, 2022 at 10:01:55PM +0800, Zhuo Chen wrote:
On 9/23/22 5:08 AM, Bjorn Helgaas wrote:
On Fri, Sep 02, 2022 at 02:16:33AM +0800, Zhuo Chen wrote:
When state is pci_channel_io_frozen in pcie_do_recovery(),
the severity is fatal and fatal status should be cleared.
So we add pci_aer_clear_fatal_status().
Seems sensible to me. Did you find this by code inspection or by
debugging a problem? If the latter, it would be nice to mention the
symptoms of the problem in the commit log.
I found this by code inspection so I may not enumerate what kind of problems
this code will cause.
Since pcie_aer_is_native() in pci_aer_clear_fatal_status()
and pci_aer_clear_nonfatal_status() contains the function of
'if (host->native_aer || pcie_ports_native)', so we move them
out of it.
Wrap commit log to fill 75 columns.
Signed-off-by: Zhuo Chen <chenzhuo.1@xxxxxxxxxxxxx>
---
drivers/pci/pcie/err.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 0c5a143025af..e0a8ade4c3fe 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -243,10 +243,14 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
* it is responsible for clearing this status. In that case, the
* signaling device may not even be visible to the OS.
*/
- if (host->native_aer || pcie_ports_native) {
+ if (host->native_aer || pcie_ports_native)
pcie_clear_device_status(dev);
pcie_clear_device_status() doesn't check for pcie_aer_is_native()
internally, but after 068c29a248b6 ("PCI/ERR: Clear PCIe Device Status
errors only if OS owns AER") and aa344bc8b727 ("PCI/ERR: Clear AER
status only when we control AER"), both callers check before calling
it.
I think we should move the check inside pcie_clear_device_status().
That could be a separate preliminary patch.
There are a couple other places (aer_root_reset() and
get_port_device_capability()) that do the same check and could be
changed to use pcie_aer_is_native() instead. That could be another
preliminary patch.
Good suggestion. But I have only one doubt. In aer_root_reset(), if we use
"if (pcie_aer_is_native(dev) && aer)", when dev->aer_cap
is NULL and root->aer_cap is not NULL, pcie_aer_is_native() will return
false. It's different from just using "(host->native_aer ||
pcie_ports_native)".
Or if we can use "if (pcie_aer_is_native(root))", at this time a NULL
pointer check should be added in pcie_aer_is_native() because root may be
NULL.
Good point. In aer_root_reset(), we're updating Root Port registers,
so I think they should look like:
if (pcie_aer_is_native(root) && aer) {
...
}
Does that seem safe and equivalent to you?
Bjorn
I think ‘if (aer && pcie_aer_is_native(root))’ might be safer,
because when root is NULL, 'aer' will be NUll as well, and the
predicate will return false without entering pcie_aer_is_native(root).
--
Thanks,
Zhuo Chen