Re: [PATCH] ata: libata-eh: Retry non-NCQ commands when their sense data asks for it

[Igor Pylypiv <ipylypiv@google.com>]

On Fri, Oct 30, 2026 at 10:00:48AM +0100, Niklas Cassel wrote:
> When a failed command has valid sense data, ata_eh_analyze_tf() asks
> scsi_check_sense() whether the command should be retried, and sets
> ATA_QCFLAG_RETRY if it should. ata_eh_link_autopsy() then clears
> AC_ERR_DEV and AC_ERR_OTHER from qc->err_mask, relying on that decision.
> 
> For an NCQ command, qc->err_mask still has AC_ERR_NCQ, so
> ata_eh_finish() honors ATA_QCFLAG_RETRY. For a non-NCQ command, whose
> sense data comes from REQUEST SENSE DATA EXT, qc->err_mask is now zero,
> and ata_eh_finish() completes the command with scmd->retries set to
> scmd->allowed, without looking at ATA_QCFLAG_RETRY. Such a command is
> thus never retried, even when its sense data asks for a retry, e.g. a
> transient error reported as ABORTED COMMAND.
> 
> Make ata_eh_finish() honor ATA_QCFLAG_RETRY for commands with valid
> sense data. ata_eh_qc_retry() cannot be used for this: as qc->err_mask
> is zero, it increments scmd->allowed, so every retry would allow one
> more, and a persistent error would be retried forever. Instead,
> complete the command without touching scmd->allowed or scmd->retries,
> so that the SCSI midlayer retries it at most scmd->allowed times, like
> any other failed command.
> 
> Fixes: 3852e3738266 ("libata: evaluate SCSI sense code")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Reviewed-by: Igor Pylypiv <ipylypiv@google.com>

Thanks,
Igor