On 10/17/12 01:38, Tejun Heo wrote:
/**
+ * __blk_run_queue_uncond - run a queue whether or not it has been stopped
+ * @q: The queue to run
+ *
+ * Description:
+ * Invoke request handling on a queue if there are any pending requests.
+ * May be used to restart request handling after a request has completed.
+ * This variant runs the queue whether or not the queue has been
+ * stopped. Must be called with the queue lock held and interrupts
+ * disabled. See also @blk_run_queue.
+ */
+void __blk_run_queue_uncond(struct request_queue *q)
+{
+ if (unlikely(blk_queue_dead(q)))
+ return;
+
+ q->request_fn(q);
+}
+
+/**
* __blk_run_queue - run a single device queue
* @q: The queue to run
*
@@ -305,7 +324,7 @@ void __blk_run_queue(struct request_queue *q)
if (unlikely(blk_queue_stopped(q)))
return;
- q->request_fn(q);
+ __blk_run_queue_uncond(q);
__blk_run_queue_uncond() is a cold path and I don't think adding a
test there matters but I think it would be better if we avoid an extra
branch if possible for __blk_run_queue(). Can't we merge
blk_queue_stopped/dead() testing?
How about declaring the function __blk_run_queue_uncond() inline ? That
should allow the compiler to combine the two tests into a single test.
Bart.
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