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| author | Ming Lei <tom.leiming@gmail.com> | 2014-10-22 08:30:30 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-10-21 19:00:32 -0600 |
| commit | 76d8137a31139f0d69ecc4177497ad6b8d4f016c (patch) | |
| tree | 194c64bc760ff1aff6c21f29b9519725b1c2fc1a /block/blk-merge.c | |
| parent | 432f16e64f50fd4999a476543d04dd52f7a2d753 (diff) | |
| download | lwn-76d8137a31139f0d69ecc4177497ad6b8d4f016c.tar.gz lwn-76d8137a31139f0d69ecc4177497ad6b8d4f016c.zip | |
blk-merge: recaculate segment if it isn't less than max segments
The problem is introduced by commit 764f612c6c3c231b(blk-merge:
don't compute bi_phys_segments from bi_vcnt for cloned bio),
and merge is needed if number of current segment isn't less than
max segments.
Strictly speaking, bio->bi_vcnt shouldn't be used here since
it may not be accurate in cases of both cloned bio or bio cloned
from, but bio_segments() is a bit expensive, and bi_vcnt is still
the biggest number, so the approach should work.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-merge.c')
| -rw-r--r-- | block/blk-merge.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index ba99351c0f58..b3ac40aef46b 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -99,16 +99,17 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio) { bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags); + bool merge_not_need = bio->bi_vcnt < queue_max_segments(q); if (no_sg_merge && !bio_flagged(bio, BIO_CLONED) && - bio->bi_vcnt < queue_max_segments(q)) + merge_not_need) bio->bi_phys_segments = bio->bi_vcnt; else { struct bio *nxt = bio->bi_next; bio->bi_next = NULL; bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, - no_sg_merge); + no_sg_merge && merge_not_need); bio->bi_next = nxt; } |