From: Yu Kuai <yukuai3@huawei.com> mainline inclusion from mainline-v6.9-rc1 commit dfa8ecd167c1753d4fc24a517e1d79c603183c94 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8374 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- read_balance() is hard to understand because there are too many status and branches, and it's overlong. This patch factor out the case to read the slow rdev from read_balance(), there are no functional changes. Co-developed-by: Paul Luse <paul.e.luse@linux.intel.com> Signed-off-by: Paul Luse <paul.e.luse@linux.intel.com> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20240229095714.926789-9-yukuai1@huaweicloud.com Signed-off-by: Li Nan <linan122@huawei.com> --- drivers/md/raid1.c | 69 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 52 insertions(+), 17 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index c548dbc80636..42879db48fd5 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -616,6 +616,53 @@ static int choose_first_rdev(struct r1conf *conf, struct r1bio *r1_bio, return -1; } +static int choose_slow_rdev(struct r1conf *conf, struct r1bio *r1_bio, + int *max_sectors) +{ + sector_t this_sector = r1_bio->sector; + int bb_disk = -1; + int bb_read_len = 0; + int disk; + + for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) { + struct md_rdev *rdev; + int len; + int read_len; + + if (r1_bio->bios[disk] == IO_BLOCKED) + continue; + + rdev = conf->mirrors[disk].rdev; + if (!rdev || test_bit(Faulty, &rdev->flags) || + !test_bit(WriteMostly, &rdev->flags)) + continue; + + /* there are no bad blocks, we can use this disk */ + len = r1_bio->sectors; + read_len = raid1_check_read_range(rdev, this_sector, &len); + if (read_len == r1_bio->sectors) { + update_read_sectors(conf, disk, this_sector, read_len); + return disk; + } + + /* + * there are partial bad blocks, choose the rdev with largest + * read length. + */ + if (read_len > bb_read_len) { + bb_disk = disk; + bb_read_len = read_len; + } + } + + if (bb_disk != -1) { + *max_sectors = bb_read_len; + update_read_sectors(conf, bb_disk, this_sector, bb_read_len); + } + + return bb_disk; +} + /* * This routine returns the disk from which the requested read should * be done. There is a per-array 'next expected sequential IO' sector @@ -669,23 +716,8 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect if (!test_bit(In_sync, &rdev->flags) && rdev->recovery_offset < this_sector + sectors) continue; - if (test_bit(WriteMostly, &rdev->flags)) { - /* Don't balance among write-mostly, just - * use the first as a last resort */ - if (best_dist_disk < 0) { - if (is_badblock(rdev, this_sector, sectors, - &first_bad, &bad_sectors)) { - if (first_bad <= this_sector) - /* Cannot use this */ - continue; - best_good_sectors = first_bad - this_sector; - } else - best_good_sectors = sectors; - best_dist_disk = disk; - best_pending_disk = disk; - } + if (test_bit(WriteMostly, &rdev->flags)) continue; - } /* This is a reasonable device to use. It might * even be best. */ @@ -804,7 +836,10 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect } *max_sectors = sectors; - return best_disk; + if (best_disk >= 0) + return best_disk; + + return choose_slow_rdev(conf, r1_bio, max_sectors); } static void wake_up_barrier(struct r1conf *conf) -- 2.39.2