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authorJens Axboe <axboe@fb.com>2015-04-18 01:23:59 +0300
committerJens Axboe <axboe@fb.com>2015-05-05 22:32:49 +0300
commitdac56212e8127dbc0bff7be35c508bc280213309 (patch)
treea1a066d7f6deb7d66403137b8edafb394ce0ca6a /drivers
parentc4cf5261f8bffd9de132b50660a69148e7575bd6 (diff)
downloadlinux-dac56212e8127dbc0bff7be35c508bc280213309.tar.xz
bio: skip atomic inc/dec of ->bi_cnt for most use cases
Struct bio has a reference count that controls when it can be freed. Most uses cases is allocating the bio, which then returns with a single reference to it, doing IO, and then dropping that single reference. We can remove this atomic_dec_and_test() in the completion path, if nobody else is holding a reference to the bio. If someone does call bio_get() on the bio, then we flag the bio as now having valid count and that we must properly honor the reference count when it's being put. Tested-by: Robert Elliott <elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/bcache/request.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index ab43faddb447..1616f668a4cb 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -619,7 +619,7 @@ static void do_bio_hook(struct search *s, struct bio *orig_bio)
bio->bi_end_io = request_endio;
bio->bi_private = &s->cl;
- atomic_set(&bio->bi_cnt, 3);
+ bio_cnt_set(bio, 3);
}
static void search_free(struct closure *cl)