[SCSI] set error value when failing commands in prep_fn

set DID_NO_CONNECT for the BLKPREP_KILL case and correct a few
BLKPREP_DEFER cases that weren't checking for the need to plug the
queue.
Signed-Off-By: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_lib.c

@@ -1146,7 +1146,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 	if (unlikely(!scsi_device_online(sdev))) {
 		printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to offline device\n",
 		       sdev->host->host_no, sdev->id, sdev->lun);
-		return BLKPREP_KILL;
+		goto kill;
 	}
 	if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
 		/* OK, we're not in a running state don't prep
@@ -1156,7 +1156,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 			 * at all allowed down */
 			printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to dead device\n",
 			       sdev->host->host_no, sdev->id, sdev->lun);
-			return BLKPREP_KILL;
+			goto kill;
 		}
 		/* OK, we only allow special commands (i.e. not
 		 * user initiated ones */
@@ -1188,11 +1188,11 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 		if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) {
 			if(specials_only == SDEV_QUIESCE ||
 					specials_only == SDEV_BLOCK)
-				return BLKPREP_DEFER;
+				goto defer;
 			
 			printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to device being removed\n",
 			       sdev->host->host_no, sdev->id, sdev->lun);
-			return BLKPREP_KILL;
+			goto kill;
 		}
 			
 			
@@ -1210,7 +1210,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 		cmd->tag = req->tag;
 	} else {
 		blk_dump_rq_flags(req, "SCSI bad req");
-		return BLKPREP_KILL;
+		goto kill;
 	}
 	
 	/* note the overloading of req->special.  When the tag
@@ -1248,8 +1248,13 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 		 * required).
 		 */
 		ret = scsi_init_io(cmd);
-		if (ret)	/* BLKPREP_KILL return also releases the command */
-			return ret;
+		switch(ret) {
+		case BLKPREP_KILL:
+			/* BLKPREP_KILL return also releases the command */
+			goto kill;
+		case BLKPREP_DEFER:
+			goto defer;
+		}
 		
 		/*
 		 * Initialize the actual SCSI command for this request.
@@ -1259,7 +1264,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 			if (unlikely(!drv->init_command(cmd))) {
 				scsi_release_buffers(cmd);
 				scsi_put_command(cmd);
-				return BLKPREP_KILL;
+				goto kill;
 			}
 		} else {
 			memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
@@ -1290,6 +1295,9 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 	if (sdev->device_busy == 0)
 		blk_plug_device(q);
 	return BLKPREP_DEFER;
+ kill:
+	req->errors = DID_NO_CONNECT << 16;
+	return BLKPREP_KILL;
 }
 
 /*