[PATCH] blk_insert_request() buglet

blk_insert_request() unconditionally calls q->request_fn(q) regardless
of the plug state of the queue. This means that we could invoke
request_fn with a plugged queue, which is an invalid state.

Also fix a Jamesism style in there.

drivers/block/ll_rw_blk.c

@@ -1737,9 +1737,9 @@ void blk_insert_request(request_queue_t *q, struct request *rq,
 	/*
 	 * If command is tagged, release the tag
 	 */
-	if(reinsert) {
+	if (reinsert)
 		blk_requeue_request(q, rq);
-	} else {
+	else {
 		int where = ELEVATOR_INSERT_BACK;
 
 		if (at_head)
@@ -1751,7 +1751,10 @@ void blk_insert_request(request_queue_t *q, struct request *rq,
 		drive_stat_acct(rq, rq->nr_sectors, 1);
 		__elv_add_request(q, rq, where, 0);
 	}
-	q->request_fn(q);
+	if (blk_queue_plugged(q))
+		__generic_unplug_device(q);
+	else
+		q->request_fn(q);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }