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authorNeilBrown <neilb@suse.com>2017-03-15 06:05:12 +0300
committerShaohua Li <shli@fb.com>2017-03-23 05:15:42 +0300
commit497280509f32340d90feac030bce18006a3e3605 (patch)
tree02522e712f7b95b35ab1c23c04702f77b0275028 /drivers/md/raid5-cache.c
parent48df498daf62e1292868005675331929305067f0 (diff)
downloadlinux-497280509f32340d90feac030bce18006a3e3605.tar.xz
md/raid5: use md_write_start to count stripes, not bios
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 now, raid5_make_request() calls md_write_start() and then md_write_end() to keep the count elevated during the setup of the request. add_stripe_bio() calls md_write_start() for each stripe_head, and the completion routines always call md_write_end(), instead of only calling it when raid5_dec_bi_active_stripes() returns 0. make_discard_request also calls md_write_start/end(). The parallel between md_write_{start,end} and use of bi_phys_segments can be seen in that: Whenever we set bi_phys_segments to 1, we now call md_write_start. Whenever we increment it on non-read requests with raid5_inc_bi_active_stripes(), we now call md_write_start(). Whenever we decrement bi_phys_segments on non-read requsts with raid5_dec_bi_active_stripes(), we now call md_write_end(). This reduces our dependence on keeping a per-bio count of active stripes in bi_phys_segments. md_write_inc() is added which parallels md_write_start(), but requires that a write has already been started, and is certain never to sleep. This can be used inside a spinlocked region when adding to a write request. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5-cache.c')
-rw-r--r--drivers/md/raid5-cache.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 64493132470b..f5034ecb4e94 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -318,8 +318,8 @@ r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev,
while (wbi && wbi->bi_iter.bi_sector <
dev->sector + STRIPE_SECTORS) {
wbi2 = r5_next_bio(wbi, dev->sector);
+ md_write_end(conf->mddev);
if (!raid5_dec_bi_active_stripes(wbi)) {
- md_write_end(conf->mddev);
bio_list_add(return_bi, wbi);
}
wbi = wbi2;