• Dan Williams's avatar
    [SCSI] libsas: close error handling vs sas_ata_task_done() race · 3dff5721
    Dan Williams authored
    Since sas_ata does not implement ->freeze(), completions for scmds and
    internal commands can still arrive concurrent with
    ata_scsi_cmd_error_handler() and sas_ata_post_internal() respectively.
    By the time either of those is called libata has committed to completing
    the qc, and the ATA_PFLAG_FROZEN flag tells sas_ata_task_done() it has
    lost the race.
    
    In the sas_ata_post_internal() case we take on the additional
    responsibility of freeing the sas_task to close the race with
    sas_ata_task_done() freeing the the task while sas_ata_post_internal()
    is in the process of invoking ->lldd_abort_task().
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
    3dff5721
sas_scsi_host.c 27 KB