[SCSI] libsas: Don't give scsi_cmnds to the EH if they never made it to the SAS LLDD or have already returned

On a system with many SAS targets, it appears possible that a scsi_cmnd
can time out without ever making it to the SAS LLDD or at the same time
that a completion is occurring.  In both of these cases, telling the
LLDD to abort the sas_task makes no sense because the LLDD won't know
about the sas_task; what we really want to do is to increase the timer.
Note that this involves creating another sas_task bit to indicate
whether or not the task has been sent to the LLDD; I could have
implemented this by slightly redefining SAS_TASK_STATE_PENDING, but
this way seems cleaner.

This second version amends the aic94xx portion to set the
TASK_AT_INITIATOR flag for all sas_tasks that were passed to
lldd_execute_task.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 22672d54aa27..21bd24775980 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -542,6 +542,13 @@ enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)
                             cmd, task);
                 return EH_HANDLED;
         }
+        if (!(task->task_state_flags & SAS_TASK_AT_INITIATOR)) {
+                spin_unlock_irqrestore(&task->task_state_lock, flags);
+                SAS_DPRINTK("command 0x%p, task 0x%p, not at initiator: "
+                            "EH_RESET_TIMER\n",
+                            cmd, task);
+                return EH_RESET_TIMER;
+        }
         task->task_state_flags |= SAS_TASK_STATE_ABORTED;
         spin_unlock_irqrestore(&task->task_state_lock, flags);