• Dan Williams's avatar
    [SCSI] libsas: fix timeout vs completion race · 9095a64a
    Dan Williams authored
    Until we have told the lldd to forget a task a timed out operation can
    return from the hardware at any time.  Since completion frees the task
    we need to make sure that no tasks run their normal completion handler
    once eh has decided to manage the task.  Similar to
    ata_scsi_cmd_error_handler() freeze completions to let eh judge the
    outcome of the race.
    Task collector mode is problematic because it presents a situation where
    a task can be timed out and aborted before the lldd has even seen it.
    For this case we need to guarantee that a task that an lldd has been
    told to forget does not get queued after the lldd says "never seen it".
    With sas_scsi_timed_out we achieve this with the ->task_queue_flush
    mutex, rather than adding more time.
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
sas_ata.h 2.08 KB