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authorMing Lei <ming.lei@redhat.com>2019-02-15 19:13:23 +0800
committerJens Axboe <axboe@kernel.dk>2019-02-15 08:40:12 -0700
commit2705c93742e91730d335838025d75d8043861174 (patch)
tree16e379f17a745cbb3a1f8d7ba5ffe7e2b8ddee86 /block/blk-mq.c
parentac4fa1d107addb2c6b21067d8945a39316a09fc8 (diff)
downloadlinux-2705c93742e91730d335838025d75d8043861174.tar.bz2
block: kill QUEUE_FLAG_NO_SG_MERGE
Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"), physical segment number is mainly figured out in blk_queue_split() for fast path, and the flag of BIO_SEG_VALID is set there too. Now only blk_recount_segments() and blk_recalc_rq_segments() use this flag. Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID is set in blk_queue_split(). For another user of blk_recalc_rq_segments(): - run in partial completion branch of blk_update_request, which is an unusual case - run in blk_cloned_rq_check_limits(), still not a big problem if the flag is killed since dm-rq is the only user. Multi-page bvec is enabled now, not doing S/G merging is rather pointless with the current setup of the I/O path, as it isn't going to save you a significant amount of cycles. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 44d471ff8754..fa508ee31742 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2837,9 +2837,6 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
set->map[HCTX_TYPE_POLL].nr_queues)
blk_queue_flag_set(QUEUE_FLAG_POLL, q);
- if (!(set->flags & BLK_MQ_F_SG_MERGE))
- blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q);
-
q->sg_reserved_size = INT_MAX;
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);