md/raid5: avoid redundant bio clone in raid5_read_one_chunk

After enable io accounting, chunk read bio could be cloned twice which
is not good. To avoid such inefficiency, let's clone align_bio from
io_acct_set too, then we need only call md_account_bio in make_request
unconditionally.

Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: Song Liu <song@kernel.org>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 5a05277f4be728eee40e7d431434a9ff26023c9e..f83623ac8c34d605e1ca554e2f5f167e6fe01929 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5364,11 +5364,13 @@ static struct bio *remove_bio_from_retry(struct r5conf *conf,
  */
 static void raid5_align_endio(struct bio *bi)
 {
-       struct bio* raid_bi  = bi->bi_private;
+       struct md_io_acct *md_io_acct = bi->bi_private;
+       struct bio *raid_bi = md_io_acct->orig_bio;
        struct mddev *mddev;
        struct r5conf *conf;
        struct md_rdev *rdev;
        blk_status_t error = bi->bi_status;
+       unsigned long start_time = md_io_acct->start_time;
 
        bio_put(bi);
 
@@ -5380,6 +5382,8 @@ static void raid5_align_endio(struct bio *bi)
        rdev_dec_pending(rdev, conf->mddev);
 
        if (!error) {
+               if (blk_queue_io_stat(raid_bi->bi_bdev->bd_disk->queue))
+                       bio_end_io_acct(raid_bi, start_time);
                bio_endio(raid_bi);
                if (atomic_dec_and_test(&conf->active_aligned_reads))
                        wake_up(&conf->wait_for_quiescent);
@@ -5398,6 +5402,7 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
        struct md_rdev *rdev;
        sector_t sector, end_sector, first_bad;
        int bad_sectors, dd_idx;
+       struct md_io_acct *md_io_acct;
 
        if (!in_chunk_boundary(mddev, raid_bio)) {
                pr_debug("%s: non aligned\n", __func__);
@@ -5434,14 +5439,18 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
                return 0;
        }
 
-       align_bio = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->bio_set);
+       align_bio = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->io_acct_set);
+       md_io_acct = container_of(align_bio, struct md_io_acct, bio_clone);
+       raid_bio->bi_next = (void *)rdev;
+       if (blk_queue_io_stat(raid_bio->bi_bdev->bd_disk->queue))
+               md_io_acct->start_time = bio_start_io_acct(raid_bio);
+       md_io_acct->orig_bio = raid_bio;
+
        bio_set_dev(align_bio, rdev->bdev);
        align_bio->bi_end_io = raid5_align_endio;
-       align_bio->bi_private = raid_bio;
+       align_bio->bi_private = md_io_acct;
        align_bio->bi_iter.bi_sector = sector;
 
-       raid_bio->bi_next = (void *)rdev;
-
        /* No reshape active, so we can trust rdev->data_offset */
        align_bio->bi_iter.bi_sector += rdev->data_offset;
 
@@ -5468,7 +5477,6 @@ static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
        sector_t sector = raid_bio->bi_iter.bi_sector;
        unsigned chunk_sects = mddev->chunk_sectors;
        unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
-       struct r5conf *conf = mddev->private;
 
        if (sectors < bio_sectors(raid_bio)) {
                struct r5conf *conf = mddev->private;
@@ -5478,9 +5486,6 @@ static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
                raid_bio = split;
        }
 
-       if (raid_bio->bi_pool != &conf->bio_split)
-               md_account_bio(mddev, &raid_bio);
-
        if (!raid5_read_one_chunk(mddev, raid_bio))
                return raid_bio;
 
@@ -5760,7 +5765,6 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
        DEFINE_WAIT(w);
        bool do_prepare;
        bool do_flush = false;
-       bool do_clone = false;
 
        if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
                int ret = log_handle_flush_request(conf, bi);
@@ -5789,7 +5793,6 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
        if (rw == READ && mddev->degraded == 0 &&
            mddev->reshape_position == MaxSector) {
                bi = chunk_aligned_read(mddev, bi);
-               do_clone = true;
                if (!bi)
                        return true;
        }
@@ -5804,9 +5807,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
        last_sector = bio_end_sector(bi);
        bi->bi_next = NULL;
 
-       if (!do_clone)
-               md_account_bio(mddev, &bi);
-
+       md_account_bio(mddev, &bi);
        prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
        for (; logical_sector < last_sector; logical_sector += RAID5_STRIPE_SECTORS(conf)) {
                int previous;