Commit b99f8fd2 authored by Li Nan's avatar Li Nan Committed by Song Liu
Browse files

md/raid10: factor out dereference_rdev_and_rrdev() 



Factor out a helper to get 'rdev' and 'replacement' from config->mirrors.
Just to make code cleaner and prepare to fix the bug of io loss while
'replacement' replace 'rdev'.

There is no functional change.

Signed-off-by: default avatarLi Nan <linan122@huawei.com>
Link: https://lore.kernel.org/r/20230701080529.2684932-3-linan666@huaweicloud.com


Signed-off-by: default avatarSong Liu <song@kernel.org>
parent 7e85c41b

drivers/md/raid10.c

+20 −9
Original line number Diff line number Diff line
@@ -1321,6 +1321,25 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio, 
	}

}



static struct md_rdev *dereference_rdev_and_rrdev(struct raid10_info *mirror,

						  struct md_rdev **prrdev)

{

	struct md_rdev *rdev, *rrdev;



	rrdev = rcu_dereference(mirror->replacement);

	/*

	 * Read replacement first to prevent reading both rdev and

	 * replacement as NULL during replacement replace rdev.

	 */

	smp_mb();

	rdev = rcu_dereference(mirror->rdev);

	if (rdev == rrdev)

		rrdev = NULL;



	*prrdev = rrdev;

	return rdev;

}



static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)

{

	int i;
@@ -1464,15 +1483,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, 
		int d = r10_bio->devs[i].devnum;

		struct md_rdev *rdev, *rrdev;



		rrdev = rcu_dereference(conf->mirrors[d].replacement);

		/*

		 * Read replacement first to prevent reading both rdev and

		 * replacement as NULL during replacement replace rdev.

		 */

		smp_mb();

		rdev = rcu_dereference(conf->mirrors[d].rdev);

		if (rdev == rrdev)

			rrdev = NULL;

		rdev = dereference_rdev_and_rrdev(&conf->mirrors[d], &rrdev);

		if (rdev && (test_bit(Faulty, &rdev->flags)))

			rdev = NULL;

		if (rrdev && (test_bit(Faulty, &rrdev->flags)))