Commit 605eeda6 authored by Li Nan's avatar Li Nan Committed by Song Liu
Browse files

md/raid10: optimize fix_read_error 



We dereference r10_bio->read_slot too many times in fix_read_error().
Optimize it by using a variable to store read_slot.

Signed-off-by: default avatarLi Nan <linan122@huawei.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20230623173236.2513554-2-linan666@huaweicloud.com


Signed-off-by: default avatarSong Liu <song@kernel.org>
parent ffb1e7a0

drivers/md/raid10.c

+10 −10
Original line number Diff line number Diff line
@@ -2718,10 +2718,10 @@ static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector, 
static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)

{

	int sect = 0; /* Offset from r10_bio->sector */

	int sectors = r10_bio->sectors;

	int sectors = r10_bio->sectors, slot = r10_bio->read_slot;

	struct md_rdev *rdev;

	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);

	int d = r10_bio->devs[r10_bio->read_slot].devnum;

	int d = r10_bio->devs[slot].devnum;



	/* still own a reference to this rdev, so it cannot

	 * have been cleared recently.
@@ -2742,13 +2742,13 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10 
		pr_notice("md/raid10:%s: %pg: Failing raid device\n",

			  mdname(mddev), rdev->bdev);

		md_error(mddev, rdev);

		r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;

		r10_bio->devs[slot].bio = IO_BLOCKED;

		return;

	}



	while(sectors) {

		int s = sectors;

		int sl = r10_bio->read_slot;

		int sl = slot;

		int success = 0;

		int start;
@@ -2783,7 +2783,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10 
			sl++;

			if (sl == conf->copies)

				sl = 0;

		} while (!success && sl != r10_bio->read_slot);

		} while (!success && sl != slot);

		rcu_read_unlock();



		if (!success) {
@@ -2791,16 +2791,16 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10 
			 * as bad on the first device to discourage future

			 * reads.

			 */

			int dn = r10_bio->devs[r10_bio->read_slot].devnum;

			int dn = r10_bio->devs[slot].devnum;

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



			if (!rdev_set_badblocks(

				    rdev,

				    r10_bio->devs[r10_bio->read_slot].addr

				    r10_bio->devs[slot].addr

				    + sect,

				    s, 0)) {

				md_error(mddev, rdev);

				r10_bio->devs[r10_bio->read_slot].bio

				r10_bio->devs[slot].bio

					= IO_BLOCKED;

			}

			break;
@@ -2809,7 +2809,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10 
		start = sl;

		/* write it back and re-read */

		rcu_read_lock();

		while (sl != r10_bio->read_slot) {

		while (sl != slot) {

			if (sl==0)

				sl = conf->copies;

			sl--;
@@ -2843,7 +2843,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10 
			rcu_read_lock();

		}

		sl = start;

		while (sl != r10_bio->read_slot) {

		while (sl != slot) {

			if (sl==0)

				sl = conf->copies;

			sl--;