md: fix up raid1/raid10 unplugging.

We just need to make sure that an unplug event wakes up the md
thread, which is exactly what mddev_check_plugged does.

Also remove some plug-related code that is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/raid1.c

@@ -565,12 +565,6 @@ static void flush_pending_writes(conf_t *conf)
 		spin_unlock_irq(&conf->device_lock);
 }
 
-static void md_kick_device(mddev_t *mddev)
-{
-	blk_flush_plug(current);
-	md_wakeup_thread(mddev->thread);
-}
-
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -600,7 +594,7 @@ static void raise_barrier(conf_t *conf)
 
 	/* Wait until no block IO is waiting */
 	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	/* block any new IO from starting */
 	conf->barrier++;
@@ -608,7 +602,7 @@ static void raise_barrier(conf_t *conf)
 	/* Now wait for all pending IO to complete */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -630,7 +624,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    md_kick_device(conf->mddev));
+				    );
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -666,8 +660,7 @@ static void freeze_array(conf_t *conf)
 	wait_event_lock_irq(conf->wait_barrier,
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
-			    ({ flush_pending_writes(conf);
-			       md_kick_device(conf->mddev); }));
+			    flush_pending_writes(conf));
 	spin_unlock_irq(&conf->resync_lock);
 }
 static void unfreeze_array(conf_t *conf)
@@ -729,6 +722,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
 	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 	mdk_rdev_t *blocked_rdev;
+	int plugged;
 
 	/*
 	 * Register the new request and wait if the reconstruction
@@ -820,6 +814,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	 * inc refcount on their rdev.  Record them by setting
 	 * bios[x] to bio
 	 */
+	plugged = mddev_check_plugged(mddev);
+
 	disks = conf->raid_disks;
  retry_write:
 	blocked_rdev = NULL;
@@ -925,7 +921,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	/* In case raid1d snuck in to freeze_array */
 	wake_up(&conf->wait_barrier);
 
-	if (do_sync || !bitmap)
+	if (do_sync || !bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
 
 	return 0;
@@ -1524,7 +1520,8 @@ static void raid1d(mddev_t *mddev)
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
-		flush_pending_writes(conf);
+		if (atomic_read(&mddev->plug_cnt) == 0)
+			flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {
@@ -2042,7 +2039,6 @@ static int stop(mddev_t *mddev)
 
 	md_unregister_thread(mddev->thread);
 	mddev->thread = NULL;
-	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	if (conf->r1bio_pool)
 		mempool_destroy(conf->r1bio_pool);
 	kfree(conf->mirrors);

drivers/md/raid10.c

@@ -634,12 +634,6 @@ static void flush_pending_writes(conf_t *conf)
 		spin_unlock_irq(&conf->device_lock);
 }
 
-static void md_kick_device(mddev_t *mddev)
-{
-	blk_flush_plug(current);
-	md_wakeup_thread(mddev->thread);
-}
-
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -669,15 +663,15 @@ static void raise_barrier(conf_t *conf, int force)
 
 	/* Wait until no block IO is waiting (unless 'force') */
 	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	/* block any new IO from starting */
 	conf->barrier++;
 
-	/* No wait for all pending IO to complete */
+	/* Now wait for all pending IO to complete */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -698,7 +692,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    md_kick_device(conf->mddev));
+				    );
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -734,8 +728,8 @@ static void freeze_array(conf_t *conf)
 	wait_event_lock_irq(conf->wait_barrier,
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
-			    ({ flush_pending_writes(conf);
-			       md_kick_device(conf->mddev); }));
+			    flush_pending_writes(conf));
+
 	spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -762,6 +756,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
 	unsigned long flags;
 	mdk_rdev_t *blocked_rdev;
+	int plugged;
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
@@ -870,6 +865,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	 * inc refcount on their rdev.  Record them by setting
 	 * bios[x] to bio
 	 */
+	plugged = mddev_check_plugged(mddev);
+
 	raid10_find_phys(conf, r10_bio);
  retry_write:
 	blocked_rdev = NULL;
@@ -946,9 +943,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	/* In case raid10d snuck in to freeze_array */
 	wake_up(&conf->wait_barrier);
 
-	if (do_sync || !mddev->bitmap)
+	if (do_sync || !mddev->bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
-
 	return 0;
 }