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Commit 96c3fd1f authored by NeilBrown's avatar NeilBrown
Browse files

md/raid10: change read_balance to return an rdev 



It makes more sense to return an rdev than just an index as
read_balance() gets a reference to the rdev and so returning
the pointer make this more idiomatic.

This will be needed in a future patch when we might return
a 'replacement' rdev instead of the main rdev.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 69335ef3

drivers/md/raid10.c

+13 −14
Original line number Diff line number Diff line
@@ -590,7 +590,9 @@ static int raid10_mergeable_bvec(struct request_queue *q, 
 * FIXME: possibly should rethink readbalancing and do it differently

 * depending on near_copies / far_copies geometry.

 */

static int read_balance(struct r10conf *conf, struct r10bio *r10_bio, int *max_sectors)

static struct md_rdev *read_balance(struct r10conf *conf,

				    struct r10bio *r10_bio,

				    int *max_sectors)

{

	const sector_t this_sector = r10_bio->sector;

	int disk, slot;
@@ -703,11 +705,11 @@ static int read_balance(struct r10conf *conf, struct r10bio *r10_bio, int *max_s 
		}

		r10_bio->read_slot = slot;

	} else

		disk = -1;

		rdev = NULL;

	rcu_read_unlock();

	*max_sectors = best_good_sectors;



	return disk;

	return rdev;

}



static int raid10_congested(void *data, int bits)
@@ -874,7 +876,6 @@ static void unfreeze_array(struct r10conf *conf) 
static void make_request(struct mddev *mddev, struct bio * bio)

{

	struct r10conf *conf = mddev->private;

	struct mirror_info *mirror;

	struct r10bio *r10_bio;

	struct bio *read_bio;

	int i;
@@ -973,17 +974,16 @@ static void make_request(struct mddev *mddev, struct bio * bio) 
		/*

		 * read balancing logic:

		 */

		int disk;

		struct md_rdev *rdev;

		int slot;



read_again:

		disk = read_balance(conf, r10_bio, &max_sectors);

		slot = r10_bio->read_slot;

		if (disk < 0) {

		rdev = read_balance(conf, r10_bio, &max_sectors);

		if (!rdev) {

			raid_end_bio_io(r10_bio);

			return;

		}

		mirror = conf->mirrors + disk;

		slot = r10_bio->read_slot;



		read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);

		md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector,
@@ -992,8 +992,8 @@ static void make_request(struct mddev *mddev, struct bio * bio) 
		r10_bio->devs[slot].bio = read_bio;



		read_bio->bi_sector = r10_bio->devs[slot].addr +

			mirror->rdev->data_offset;

		read_bio->bi_bdev = mirror->rdev->bdev;

			rdev->data_offset;

		read_bio->bi_bdev = rdev->bdev;

		read_bio->bi_end_io = raid10_end_read_request;

		read_bio->bi_rw = READ | do_sync;

		read_bio->bi_private = r10_bio;
@@ -2116,8 +2116,8 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio) 
	r10_bio->devs[slot].bio =

		mddev->ro ? IO_BLOCKED : NULL;

read_more:

	mirror = read_balance(conf, r10_bio, &max_sectors);

	if (mirror == -1) {

	rdev = read_balance(conf, r10_bio, &max_sectors);

	if (rdev == NULL) {

		printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"

		       " read error for block %llu\n",

		       mdname(mddev), b,
@@ -2131,7 +2131,6 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio) 
	if (bio)

		bio_put(bio);

	slot = r10_bio->read_slot;

	rdev = conf->mirrors[mirror].rdev;

	printk_ratelimited(

		KERN_ERR

		"md/raid10:%s: %s: redirecting"