Commit 1a67356e authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe

block: don't use bio->bi_vcnt to figure out segment number

It is wrong to use bio->bi_vcnt to figure out how many segments
there are in the bio even though CLONED flag isn't set on this bio,
because this bio may be splitted or advanced.

So always use bio_segments() in blk_recount_segments(), and it shouldn't
cause any performance loss now because the physical segment number is figured
out in blk_queue_split() and BIO_SEG_VALID is set meantime since
bdced438 ("block: setup bi_phys_segments after splitting").
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Fixes: 76d8137a ("blk-merge: recaculate segment if it isn't less than max segments")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8a2ee44a
......@@ -367,13 +367,7 @@ void blk_recalc_rq_segments(struct request *rq)
void blk_recount_segments(struct request_queue *q, struct bio *bio)
{
unsigned short seg_cnt;
/* estimate segment number by bi_vcnt for non-cloned bio */
if (bio_flagged(bio, BIO_CLONED))
seg_cnt = bio_segments(bio);
else
seg_cnt = bio->bi_vcnt;
unsigned short seg_cnt = bio_segments(bio);
if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) &&
(seg_cnt < queue_max_segments(q)))
......
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