[PATCH 2/5] scsi: make scsi_eh_scmd_add() always succeed

[Hannes Reinecke <hare@suse.de>]

scsi_eh_scmd_add() currently only will fail if no
error handler thread is started (which will never be the
case) or if the state machine encounters an illegal transition.

But if we're encountering an invalid state transition
chances is we cannot fixup things with the error handler.
So better add a WARN_ON for illegal host states and
make scsi_dh_scmd_add() a void function.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_error.c | 39 +++++++++++++--------------------------
 drivers/scsi/scsi_lib.c   |  4 ++--
 drivers/scsi/scsi_priv.h  |  2 +-
 3 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 984ddcb..deb35737 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -162,13 +162,7 @@ scmd_eh_abort_handler(struct work_struct *work)
 		}
 	}
 
-	if (!scsi_eh_scmd_add(scmd, 0)) {
-		SCSI_LOG_ERROR_RECOVERY(3,
-			scmd_printk(KERN_WARNING, scmd,
-				    "terminate aborted command\n"));
-		set_host_byte(scmd, DID_TIME_OUT);
-		scsi_finish_command(scmd);
-	}
+	scsi_eh_scmd_add(scmd, 0);
 }
 
 /**
@@ -224,37 +218,32 @@ scsi_abort_command(struct scsi_cmnd *scmd)
  * scsi_eh_scmd_add - add scsi cmd to error handling.
  * @scmd:	scmd to run eh on.
  * @eh_flag:	optional SCSI_EH flag.
- *
- * Return value:
- *	0 on failure.
  */
-int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
+void scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
 {
 	struct Scsi_Host *shost = scmd->device->host;
 	unsigned long flags;
-	int ret = 0;
 
-	if (!shost->ehandler)
-		return 0;
+	WARN_ON(!shost->ehandler);
 
 	spin_lock_irqsave(shost->host_lock, flags);
+	WARN_ON(shost->shost_state != SHOST_RUNNING &&
+		shost->shost_state != SHOST_CANCEL &&
+		shost->shost_state != SHOST_RECOVERY &&
+		shost->shost_state != SHOST_CANCEL_RECOVERY);
 	if (scsi_host_set_state(shost, SHOST_RECOVERY))
-		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
-			goto out_unlock;
+		scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
 
 	if (shost->eh_deadline != -1 && !shost->last_reset)
 		shost->last_reset = jiffies;
 
-	ret = 1;
 	if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
 		eh_flag &= ~SCSI_EH_CANCEL_CMD;
 	scmd->eh_eflags |= eh_flag;
 	list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 	shost->host_failed++;
 	scsi_eh_wakeup(shost);
- out_unlock:
 	spin_unlock_irqrestore(shost->host_lock, flags);
-	return ret;
 }
 
 /**
@@ -285,13 +274,11 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
 		rtn = host->hostt->eh_timed_out(scmd);
 
 	if (rtn == BLK_EH_NOT_HANDLED) {
-		if (!host->hostt->no_async_abort &&
-		    scsi_abort_command(scmd) == SUCCESS)
-			return BLK_EH_NOT_HANDLED;
-
-		set_host_byte(scmd, DID_TIME_OUT);
-		if (!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))
-			rtn = BLK_EH_HANDLED;
+		if (host->hostt->no_async_abort ||
+		    scsi_abort_command(scmd) != SUCCESS) {
+			set_host_byte(scmd, DID_TIME_OUT);
+			scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
+		}
 	}
 
 	return rtn;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index fa6b2c4..2dd7d0a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1647,8 +1647,8 @@ static void scsi_softirq_done(struct request *rq)
 			scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
 			break;
 		default:
-			if (!scsi_eh_scmd_add(cmd, 0))
-				scsi_finish_command(cmd);
+			scsi_eh_scmd_add(cmd, 0);
+			break;
 	}
 }
 
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 27b4d0a..8c26823 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -71,7 +71,7 @@ extern enum blk_eh_timer_return scsi_times_out(struct request *req);
 extern int scsi_error_handler(void *host);
 extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
 extern void scsi_eh_wakeup(struct Scsi_Host *shost);
-extern int scsi_eh_scmd_add(struct scsi_cmnd *, int);
+extern void scsi_eh_scmd_add(struct scsi_cmnd *, int);
 void scsi_eh_ready_devs(struct Scsi_Host *shost,
 			struct list_head *work_q,
 			struct list_head *done_q);
-- 
1.8.5.6