linux-kernel - Re: [PATCH 2/3] PCI/ERR: Clear fatal status in pcie_do

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Message-ID: <20220922210853.GA1335665@bhelgaas>
Date:   Thu, 22 Sep 2022 16:08:53 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Zhuo Chen <chenzhuo.1@...edance.com>
Cc:     fancer.lancer@...il.com, jdmason@...zu.us, dave.jiang@...el.com,
        allenbh@...il.com, bhelgaas@...gle.com, ruscur@...sell.cc,
        oohall@...il.com, james.smart@...adcom.com,
        dick.kennedy@...adcom.com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        ntb@...ts.linux.dev, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH 2/3] PCI/ERR: Clear fatal status in pcie_do_recovery()

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.

> 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@...edance.com>
> ---
>  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.


> +	if (state == pci_channel_io_frozen)
> +		pci_aer_clear_fatal_status(dev);
> +	else
>  		pci_aer_clear_nonfatal_status(dev);
> -	}
> +
>  	pci_info(bridge, "device recovery successful\n");
>  	return status;
>  
> -- 
> 2.30.1 (Apple Git-130)
>