[BLOCK] elevator switch fixes/cleanup

- 100msec sleep is a little excessive, lots of requests can complete
  in that timeframe. Use 10msec instead.
- Rename QUEUE_FLAG_BYPASS to QUEUE_FLAG_ELVSWITCH to indicate what
  is going on.

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

3 files changed, 6 insertions, 6 deletions

diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 272d93946621..cf9bedbb761b 100644
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -671,14 +671,14 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
          */
         spin_lock_irq(q->queue_lock);
 
-        set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+        set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
 
         while (q->elevator->ops->elevator_dispatch_fn(q, 1))
                 ;
 
         while (q->rq.elvpriv) {
                 spin_unlock_irq(q->queue_lock);
-                msleep(100);
+                msleep(10);
                 spin_lock_irq(q->queue_lock);
         }
 
@@ -703,7 +703,7 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
          * finally exit old elevator and turn off BYPASS.
          */
         elevator_exit(old_elevator);
-        clear_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+        clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
         return;
 
 fail_register:
@@ -716,7 +716,7 @@ fail_register:
 fail:
         q->elevator = old_elevator;
         elv_register_queue(q);
-        clear_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+        clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
         kfree(e);
 error:
         elevator_put(new_e);
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index f7c9931cb380..fc12d019b19d 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -1940,7 +1940,7 @@ get_rq:
         if (rl->count[rw] >= queue_congestion_on_threshold(q))
                 set_queue_congested(q, rw);
 
-        priv = !test_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+        priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
         if (priv)
                 rl->elvpriv++;
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6186d5e2110f..7d9d14d6d8f9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -442,7 +442,7 @@ enum {
 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
-#define QUEUE_FLAG_BYPASS       8       /* don't use elevator, just do FIFO */
+#define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 #define QUEUE_FLAG_FLUSH        9       /* doing barrier flush sequence */
 
 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)