[PATCH] md: remove md_flush_all

Following are 7 patches for md

They all grew out of a desire to redo the locking in unplug_slave.  Getting
and dropping a spinlock so often for very little gain (it would be nearly
impossible to lose the relevant race) really bothered me.

I finally figured that I could reply it with rcu locking which is very light
wait, and quite up to the task.

One the way I found an number of inconsistencies that needed cleaning up and
even a few bugs to fix.  The first 6 patches deal with these inconsistencies
and bugs.  The last redoes the locking for adding/removing/accessing devices
within md personalities.


This patch:

md_flush_all() isn't needed as each personality defines its own
issue_flush_fn.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/md.c

@@ -154,38 +154,6 @@ static spinlock_t all_mddevs_lock = SPIN_LOCK_UNLOCKED;
 		tmp = tmp->next;})					\
 		)
 
-int md_flush_mddev(mddev_t *mddev, sector_t *error_sector)
-{
-	struct list_head *tmp;
-	mdk_rdev_t *rdev;
-	int ret = 0;
-
-	/*
-	 * this list iteration is done without any locking in md?!
-	 */
-	ITERATE_RDEV(mddev, rdev, tmp) {
-		request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
-		int err;
-
-		if (!r_queue->issue_flush_fn)
-			err = -EOPNOTSUPP;
-		else
-			err = r_queue->issue_flush_fn(r_queue, rdev->bdev->bd_disk, error_sector);
-
-		if (!ret)
-			ret = err;
-	}
-
-	return ret;
-}
-
-static int md_flush_all(request_queue_t *q, struct gendisk *disk,
-			 sector_t *error_sector)
-{
-	mddev_t *mddev = q->queuedata;
-
-	return md_flush_mddev(mddev, error_sector);
-}
 
 static int md_fail_request (request_queue_t *q, struct bio *bio)
 {
@@ -1714,7 +1682,6 @@ static int do_md_run(mddev_t * mddev)
 	 */
 	mddev->queue->queuedata = mddev;
 	mddev->queue->make_request_fn = mddev->pers->make_request;
-	mddev->queue->issue_flush_fn = md_flush_all;
 
 	mddev->changed = 1;
 	return 0;