Merge branch 'for-3.6/drivers' of git://git.kernel.dk/linux-block

Pull block driver changes from Jens Axboe:

 - Making the plugging support for drivers a bit more sane from Neil.
   This supersedes the plugging change from Shaohua as well.

 - The usual round of drbd updates.

 - Using a tail add instead of a head add in the request completion for
   ndb, making us find the most completed request more quickly.

 - A few floppy changes, getting rid of a duplicated flag and also
   running the floppy init async (since it takes forever in boot terms)
   from Andi.

* 'for-3.6/drivers' of git://git.kernel.dk/linux-block:
  floppy: remove duplicated flag FD_RAW_NEED_DISK
  blk: pass from_schedule to non-request unplug functions.
  block: stack unplug
  blk: centralize non-request unplug handling.
  md: remove plug_cnt feature of plugging.
  block/nbd: micro-optimization in nbd request completion
  drbd: announce FLUSH/FUA capability to upper layers
  drbd: fix max_bio_size to be unsigned
  drbd: flush drbd work queue before invalidate/invalidate remote
  drbd: fix potential access after free
  drbd: call local-io-error handler early
  drbd: do not reset rs_pending_cnt too early
  drbd: reset congestion information before reporting it in /proc/drbd
  drbd: report congestion if we are waiting for some userland callback
  drbd: differentiate between normal and forced detach
  drbd: cleanup, remove two unused global flags
  floppy: Run floppy initialization asynchronous

drivers/md/md.c

@@ -498,61 +498,13 @@ void md_flush_request(struct mddev *mddev, struct bio *bio)
 }
 EXPORT_SYMBOL(md_flush_request);
 
-/* Support for plugging.
- * This mirrors the plugging support in request_queue, but does not
- * require having a whole queue or request structures.
- * We allocate an md_plug_cb for each md device and each thread it gets
- * plugged on.  This links tot the private plug_handle structure in the
- * personality data where we keep a count of the number of outstanding
- * plugs so other code can see if a plug is active.
- */
-struct md_plug_cb {
-	struct blk_plug_cb cb;
-	struct mddev *mddev;
-};
-
-static void plugger_unplug(struct blk_plug_cb *cb)
+void md_unplug(struct blk_plug_cb *cb, bool from_schedule)
 {
-	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
-	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
-		md_wakeup_thread(mdcb->mddev->thread);
-	kfree(mdcb);
+	struct mddev *mddev = cb->data;
+	md_wakeup_thread(mddev->thread);
+	kfree(cb);
 }
-
-/* Check that an unplug wakeup will come shortly.
- * If not, wakeup the md thread immediately
- */
-int mddev_check_plugged(struct mddev *mddev)
-{
-	struct blk_plug *plug = current->plug;
-	struct md_plug_cb *mdcb;
-
-	if (!plug)
-		return 0;
-
-	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
-		if (mdcb->cb.callback == plugger_unplug &&
-		    mdcb->mddev == mddev) {
-			/* Already on the list, move to top */
-			if (mdcb != list_first_entry(&plug->cb_list,
-						    struct md_plug_cb,
-						    cb.list))
-				list_move(&mdcb->cb.list, &plug->cb_list);
-			return 1;
-		}
-	}
-	/* Not currently on the callback list */
-	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
-	if (!mdcb)
-		return 0;
-
-	mdcb->mddev = mddev;
-	mdcb->cb.callback = plugger_unplug;
-	atomic_inc(&mddev->plug_cnt);
-	list_add(&mdcb->cb.list, &plug->cb_list);
-	return 1;
-}
-EXPORT_SYMBOL_GPL(mddev_check_plugged);
+EXPORT_SYMBOL(md_unplug);
 
 static inline struct mddev *mddev_get(struct mddev *mddev)
 {
@@ -602,7 +554,6 @@ void mddev_init(struct mddev *mddev)
 	atomic_set(&mddev->active, 1);
 	atomic_set(&mddev->openers, 0);
 	atomic_set(&mddev->active_io, 0);
-	atomic_set(&mddev->plug_cnt, 0);
 	spin_lock_init(&mddev->write_lock);
 	atomic_set(&mddev->flush_pending, 0);
 	init_waitqueue_head(&mddev->sb_wait);

drivers/md/md.h

@@ -266,9 +266,6 @@ struct mddev {
 	int				new_chunk_sectors;
 	int				reshape_backwards;
 
-	atomic_t			plug_cnt;	/* If device is expecting
-							 * more bios soon.
-							 */
 	struct md_thread		*thread;	/* management thread */
 	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
 	sector_t			curr_resync;	/* last block scheduled */
@@ -630,6 +627,12 @@ extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 				   struct mddev *mddev);
 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 				   struct mddev *mddev);
-extern int mddev_check_plugged(struct mddev *mddev);
 extern void md_trim_bio(struct bio *bio, int offset, int size);
+
+extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
+static inline int mddev_check_plugged(struct mddev *mddev)
+{
+	return !!blk_check_plugged(md_unplug, mddev,
+				   sizeof(struct blk_plug_cb));
+}
 #endif /* _MD_MD_H */

drivers/md/raid1.c

@@ -2247,8 +2247,7 @@ static void raid1d(struct mddev *mddev)
 	blk_start_plug(&plug);
 	for (;;) {
 
-		if (atomic_read(&mddev->plug_cnt) == 0)
-			flush_pending_writes(conf);
+		flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {

drivers/md/raid10.c

@@ -2680,8 +2680,7 @@ static void raid10d(struct mddev *mddev)
 	blk_start_plug(&plug);
 	for (;;) {
 
-		if (atomic_read(&mddev->plug_cnt) == 0)
-			flush_pending_writes(conf);
+		flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {

drivers/md/raid5.c

@@ -4562,7 +4562,7 @@ static void raid5d(struct mddev *mddev)
 	while (1) {
 		struct bio *bio;
 
-		if (atomic_read(&mddev->plug_cnt) == 0 &&
+		if (
 		    !list_empty(&conf->bitmap_list)) {
 			/* Now is a good time to flush some bitmap updates */
 			conf->seq_flush++;
@@ -4572,8 +4572,7 @@ static void raid5d(struct mddev *mddev)
 			conf->seq_write = conf->seq_flush;
 			activate_bit_delay(conf);
 		}
-		if (atomic_read(&mddev->plug_cnt) == 0)
-			raid5_activate_delayed(conf);
+		raid5_activate_delayed(conf);
 
 		while ((bio = remove_bio_from_retry(conf))) {
 			int ok;