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SubjectRe: [PATCH v2] PCIe AER: report uncorrectable errors only to the functions that logged the errors
On Fri, Aug 18, 2017 at 12:02:21PM +0100, Gabriele Paoloni wrote:
> Currently if an uncorrectable error is reported by an EP the AER
> driver walks over all the devices connected to the upstream port
> bus and in turns call the report_error_detected() callback.
> If any of the devices connected to the bus does not implement
> dev->driver->err_handler->error_detected() do_recovery() will fail
> leaving all the bus hierarchy devices unrecovered.
>
> However for non fatal errors the PCIe link should not be considered
> compromised, therefore it makes sense to report the error only to
> all the functions that logged an error.

Can you include a pointer to the relevant part of the spec here?

> This patch implements this new behaviour for non fatal errors.
>
> Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
> Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
> ---
> Changes from v1:
> - now errors are reported only to the fucntions that logged the error
> instead of all the functions in the same device.
> - the patch subject has changed to match the new implementation
> ---
> drivers/pci/pcie/aer/aerdrv_core.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
> index b1303b3..057465ad 100644
> --- a/drivers/pci/pcie/aer/aerdrv_core.c
> +++ b/drivers/pci/pcie/aer/aerdrv_core.c
> @@ -390,7 +390,14 @@ static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
> * If the error is reported by an end point, we think this
> * error is related to the upstream link of the end point.
> */
> - pci_walk_bus(dev->bus, cb, &result_data);
> + if (state == pci_channel_io_normal)
> + /*
> + * the error is non fatal so the bus is ok, just invoke
> + * the callback for the function that logged the error.
> + */
> + cb(dev, &result_data);
> + else
> + pci_walk_bus(dev->bus, cb, &result_data);

I think the concept of this change makes sense, but I don't like the
implicit connection of PCI_ERR_ROOT_UNCOR_RCV -> AER_NONFATAL ->
pci_channel_io_normal. That makes it harder than it should be to read
the code.

What would you think of changing the signature of do_recovery() and
broadcast_error_message() so they take the struct aer_err_info pointer
instead of just the severity and pci_channel_state? Then we could
check directly for AER_NONFATAL here.

Bjorn

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