scsi: remove two cancel_delayed_work() calls from the mid-layer

scsi_put_command() is either invoked before blk_start_request() or
after block layer processing has completed.  scsi_cmnd.abort_work
is scheduled from inside the SCSI timeout handler.  The block layer
guarantees that either the regular completion handler
(softirq_done_fn()) or the timeout handler (rq_timed_out_fn()) is
invoked but not both. This means that scsi_put_command() is never
invoked while abort_work is scheduled.  Hence remove the
cancel_delayed_work() call from scsi_put_command().

Similarly, scsi_abort_command() is only invoked from the SCSI
timeout handler. If scsi_abort_command() is invoked for a SCSI
command with the SCSI_EH_ABORT_SCHEDULED flag set this means that
scmd_eh_abort_handler() has already invoked scsi_queue_insert() and
hence that scsi_cmnd.abort_work is no longer pending. Hence also
remove the cancel_delayed_work() call from scsi_abort_command().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 88d46fe..53b8b94 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -334,7 +334,7 @@ void scsi_put_command(struct scsi_cmnd *cmd)
        list_del_init(&cmd->list);
        spin_unlock_irqrestore(&cmd->device->list_lock, flags);
 
-       cancel_delayed_work(&cmd->abort_work);
+       BUG_ON(delayed_work_pending(&cmd->abort_work));
 
        __scsi_put_command(cmd->device->host, cmd);
 }

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 7e95791..4f36ae2 100644 (file)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -193,7 +193,7 @@ scsi_abort_command(struct scsi_cmnd *scmd)
                SCSI_LOG_ERROR_RECOVERY(3,
                        scmd_printk(KERN_INFO, scmd,
                                    "scmd %p previous abort failed\n", scmd));
-               cancel_delayed_work(&scmd->abort_work);
+               BUG_ON(delayed_work_pending(&scmd->abort_work));
                return FAILED;
        }