scsi: core: scsi_error: Do not queue pointless abort workqueue functions

If a host template doesn't implement the .eh_abort_handler() there is no
point in queueing the abort workqueue function; all it does is invoking
SCSI EH anyway.  So return 'FAILED' from scsi_abort_command() if the
.eh_abort_handler() is not implemented and save us from having to wait for
the abort workqueue function to complete.

Cc: Niklas Cassel <[email protected]>
Cc: Damien Le Moal <[email protected]>
Cc: John Garry <[email protected]>
Signed-off-by: Hannes Reinecke <[email protected]>
[niklas: moved the check to the top of scsi_abort_command()]
Signed-off-by: Niklas Cassel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: John Garry <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: hreinecke

drivers/scsi/scsi_error.c

@@ -231,6 +231,11 @@ scsi_abort_command(struct scsi_cmnd *scmd)
 	struct Scsi_Host *shost = sdev->host;
 	unsigned long flags;
 
+	if (!shost->hostt->eh_abort_handler) {
+		/* No abort handler, fail command directly */
+		return FAILED;
+	}
+
 	if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
 		/*
 		 * Retry after abort failed, escalate to next level.