From: Yu Kuai <yukuai3@huawei.com> mainline inclusion from mainline-v6.9-rc1 commit 31a73331752d3c7d28c8fc089b21d3ae8c15e664 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 first 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/20240229095714.926789-8-yukuai1@huaweicloud.com Signed-off-by: Li Nan <linan122@huawei.com> --- drivers/md/raid1.c | 63 +++++++++++++++++++++++++++++++++------------- 1 file changed, 46 insertions(+), 17 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 05e318fec302..c548dbc80636 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -575,6 +575,47 @@ static sector_t align_to_barrier_unit_end(sector_t start_sector, return len; } +static void update_read_sectors(struct r1conf *conf, int disk, + sector_t this_sector, int len) +{ + struct raid1_info *info = &conf->mirrors[disk]; + + atomic_inc(&info->rdev->nr_pending); + if (info->next_seq_sect != this_sector) + info->seq_start = this_sector; + info->next_seq_sect = this_sector + len; +} + +static int choose_first_rdev(struct r1conf *conf, struct r1bio *r1_bio, + int *max_sectors) +{ + sector_t this_sector = r1_bio->sector; + int len = r1_bio->sectors; + int disk; + + for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) { + struct md_rdev *rdev; + int read_len; + + if (r1_bio->bios[disk] == IO_BLOCKED) + continue; + + rdev = conf->mirrors[disk].rdev; + if (!rdev || test_bit(Faulty, &rdev->flags)) + continue; + + /* choose the first disk even if it has some bad blocks. */ + read_len = raid1_check_read_range(rdev, this_sector, &len); + if (read_len > 0) { + update_read_sectors(conf, disk, this_sector, read_len); + *max_sectors = read_len; + return disk; + } + } + + return -1; +} + /* * This routine returns the disk from which the requested read should * be done. There is a per-array 'next expected sequential IO' sector @@ -599,7 +640,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect sector_t best_dist; unsigned int min_pending; struct md_rdev *rdev; - int choose_first; retry: sectors = r1_bio->sectors; @@ -610,10 +650,11 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect best_pending_disk = -1; min_pending = UINT_MAX; best_good_sectors = 0; - choose_first = raid1_should_read_first(conf->mddev, this_sector, - sectors); clear_bit(R1BIO_FailFast, &r1_bio->state); + if (raid1_should_read_first(conf->mddev, this_sector, sectors)) + return choose_first_rdev(conf, r1_bio, max_sectors); + for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) { sector_t dist; sector_t first_bad; @@ -659,8 +700,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect * bad_sectors from another device.. */ bad_sectors -= (this_sector - first_bad); - if (choose_first && sectors > bad_sectors) - sectors = bad_sectors; if (best_good_sectors > sectors) best_good_sectors = sectors; @@ -670,8 +709,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect best_good_sectors = good_sectors; best_disk = disk; } - if (choose_first) - break; } continue; } else { @@ -686,10 +723,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect pending = atomic_read(&rdev->nr_pending); dist = abs(this_sector - conf->mirrors[disk].head_position); - if (choose_first) { - best_disk = disk; - break; - } /* Don't change to another disk for sequential reads */ if (conf->mirrors[disk].next_seq_sect == this_sector || dist == 0) { @@ -765,13 +798,9 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect rdev = conf->mirrors[best_disk].rdev; if (!rdev) goto retry; - atomic_inc(&rdev->nr_pending); - sectors = best_good_sectors; - - if (conf->mirrors[best_disk].next_seq_sect != this_sector) - conf->mirrors[best_disk].seq_start = this_sector; - conf->mirrors[best_disk].next_seq_sect = this_sector + sectors; + sectors = best_good_sectors; + update_read_sectors(conf, disk, this_sector, sectors); } *max_sectors = sectors; -- 2.39.2