On 08/12/2022 10:59, Niklas Cassel wrote:
The name ATA_QCFLAG_FAILED is misleading since it does not mean that a QC was actually an error.
"QC was actually an error" sounds odd. Maybe "...it does not mean that a QC completed in error or not at all". I'm not sure on a good suggestion.
It means that libata decided to schedule EH for the QC, so the QC is now owned by the libata error handler (EH). The normal execution path is responsible for not accessing a QC owned by EH. libata core enforces the rule by returning NULL from ata_qc_from_tag() for QCs owned by EH. It is quite easy to mistake that a QC marked with ATA_QCFLAG_FAILED was an error. However, a QC that was actually an error is instead indicated by having qc->err_mask set. E.g. when we have a NCQ error, we abort all QCs, which currently will mark all QCs as ATA_QCFLAG_FAILED. However, it will only be a single QC that is an error (i.e. has qc->err_mask set). Rename ATA_QCFLAG_FAILED to ATA_QCFLAG_EH to more clearly highlight that this flag simply means that a QC is now owned by EH. This new name will not mislead to think that the QC was an error (which is instead indicated by having qc->err_mask set). This also makes it more obvious that the EH code skips all QCs that do not have ATA_QCFLAG_EH set (rather than ATA_QCFLAG_FAILED), since the EH code should simply only care about QCs that are owned by EH itself. Signed-off-by: Niklas Cassel<niklas.cassel@xxxxxxx>
FWIW, Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
