We use md_write_start() to increase the count of pending writes, and
md_write_end() to decrement the count. We currently count bios
submitted to md/raid5. Change it count stripe_heads that a WRITE bio
has been attached to.
So raid5_make_request() call md_write_start() and then md_write_end().
add_stripe_bio() calls md_write_start() for each stripe_head, and the
completion routines always call md_write_end(), instead of only
calling when raid5_dec_bi_active_stripes() returns 0.
This reduces our dependence on keeping a per-bio count of active
stripes in bi_phys_segments.
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
drivers/md/raid5.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index df88656d8798..d07d2dce6856 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2998,6 +2998,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
bi->bi_next = *bip;
*bip = bi;
raid5_inc_bi_active_stripes(bi);
+ md_write_start(conf->mddev, bi);
if (forwrite) {
/* check if page is covered */
@@ -3121,10 +3122,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
bi->bi_error = -EIO;
- if (!raid5_dec_bi_active_stripes(bi)) {
- md_write_end(conf->mddev);
+ md_write_end(conf->mddev);
+ if (!raid5_dec_bi_active_stripes(bi))
bio_list_add(return_bi, bi);
- }
bi = nextbi;
}
if (bitmap_end)
@@ -3145,10 +3145,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
bi->bi_error = -EIO;
- if (!raid5_dec_bi_active_stripes(bi)) {
- md_write_end(conf->mddev);
+ md_write_end(conf->mddev);
+ if (!raid5_dec_bi_active_stripes(bi))
bio_list_add(return_bi, bi);
- }
bi = bi2;
}
@@ -3490,10 +3489,9 @@ static void handle_stripe_clean_event(struct r5conf *conf,
while (wbi && wbi->bi_iter.bi_sector <
dev->sector + STRIPE_SECTORS) {
wbi2 = r5_next_bio(wbi, dev->sector);
- if (!raid5_dec_bi_active_stripes(wbi)) {
- md_write_end(conf->mddev);
+ md_write_end(conf->mddev);
+ if (!raid5_dec_bi_active_stripes(wbi))
bio_list_add(return_bi, wbi);
- }
wbi = wbi2;
}
bitmap_endwrite(conf->mddev->bitmap, sh->sector,
@@ -5142,9 +5140,9 @@ static void make_discard_request(struct mddev *mddev, struct bio *bi)
release_stripe_plug(mddev, sh);
}
+ md_write_end(mddev);
remaining = raid5_dec_bi_active_stripes(bi);
if (remaining == 0) {
- md_write_end(mddev);
bio_endio(bi);
}
}
@@ -5173,8 +5171,6 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi)
/* ret == -EAGAIN, fallback */
}
- md_write_start(mddev, bi);
-
/*
* If array is degraded, better not do chunk aligned read because
* later we might have to read it again in order to reconstruct
@@ -5196,6 +5192,7 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi)
last_sector = bio_end_sector(bi);
bi->bi_next = NULL;
bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
+ md_write_start(mddev, bi);
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
@@ -5324,11 +5321,11 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi)
}
finish_wait(&conf->wait_for_overlap, &w);
+ if (rw == WRITE)
+ md_write_end(mddev);
remaining = raid5_dec_bi_active_stripes(bi);
if (remaining == 0) {
- if ( rw == WRITE )
- md_write_end(mddev);
trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
bi, 0);
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
