[PATCH] Add blk_start_queueing() helper

CFQ implements this on its own now, but it's really block layer
knowledge. Tells a device queue to start dispatching requests to
the driver, taking care to unplug if needed. Also fixes the issue
where as/cfq will invoke a stopped queue, which we really don't
want.

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 4 insertions, 18 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 6fb1613d44d7..9f684cc66bd1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1553,19 +1553,6 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 }
 
 /*
- * should really be a ll_rw_blk.c helper
- */
-static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-        request_queue_t *q = cfqd->queue;
-
-        if (!blk_queue_plugged(q))
-                q->request_fn(q);
-        else
-                __generic_unplug_device(q);
-}
-
-/*
  * Called when a new fs request (rq) is added (to cfqq). Check if there's
  * something we should do about it
  */
@@ -1593,7 +1580,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                 if (cic == cfqd->active_cic &&
                     del_timer(&cfqd->idle_slice_timer)) {
                         cfq_slice_expired(cfqd, 0);
-                        cfq_start_queueing(cfqd, cfqq);
+                        blk_start_queueing(cfqd->queue);
                 }
                 return;
         }
@@ -1614,7 +1601,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                 if (cfq_cfqq_wait_request(cfqq)) {
                         cfq_mark_cfqq_must_dispatch(cfqq);
                         del_timer(&cfqd->idle_slice_timer);
-                        cfq_start_queueing(cfqd, cfqq);
+                        blk_start_queueing(cfqd->queue);
                 }
         } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
                 /*
@@ -1624,7 +1611,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                  */
                 cfq_preempt_queue(cfqd, cfqq);
                 cfq_mark_cfqq_must_dispatch(cfqq);
-                cfq_start_queueing(cfqd, cfqq);
+                blk_start_queueing(cfqd->queue);
         }
 }
 
@@ -1832,8 +1819,7 @@ static void cfq_kick_queue(void *data)
         unsigned long flags;
 
         spin_lock_irqsave(q->queue_lock, flags);
-        blk_remove_plug(q);
-        q->request_fn(q);
+        blk_start_queueing(q);
         spin_unlock_irqrestore(q->queue_lock, flags);
 }