scsi: make scsi_eh_scmd_add() always succeed

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>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 4d26ff215c74e8f83ea15567cd4aec013c96e02c..bbc431897606060d46c3cc1bc6b59a901f4f5d91 100644 (file)
--- 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);
 }
 
 /**
@@ -228,28 +222,23 @@ static void scsi_eh_reset(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;
+       int ret;
 
-       if (!shost->ehandler)
-               return 0;
+       WARN_ON_ONCE(!shost->ehandler);
 
        spin_lock_irqsave(shost->host_lock, flags);
-       if (scsi_host_set_state(shost, SHOST_RECOVERY))
-               if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
-                       goto out_unlock;
-
+       if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
+               ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
+               WARN_ON_ONCE(ret);
+       }
        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;
@@ -257,9 +246,7 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int 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;
 }
 
 /**
@@ -288,13 +275,11 @@ 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 ba2286652ff647f285761e046f3699bed5c39eba..ba8da904e774dc59f50e9cd6a68ae3169b8c713e 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1593,8 +1593,8 @@ 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 99bfc985e1903bcffd10762d52f1a72448aaed96..5be6cbf69df64d49f9d7a8de4fe1659b097fbbf9 100644 (file)
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -72,7 +72,7 @@ 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);