diff options
| -rw-r--r-- | block/blk-merge.c | 28 | ||||
| -rw-r--r-- | block/blk-mq.c | 3 | ||||
| -rw-r--r-- | include/linux/blk-mq.h | 1 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 |
4 files changed, 26 insertions, 7 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 6c583f9c5b6..b3bf0df0f4c 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -13,7 +13,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, struct bio *bio) { struct bio_vec bv, bvprv = { NULL }; - int cluster, high, highprv = 1; + int cluster, high, highprv = 1, no_sg_merge; unsigned int seg_size, nr_phys_segs; struct bio *fbio, *bbio; struct bvec_iter iter; @@ -35,12 +35,21 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, cluster = blk_queue_cluster(q); seg_size = 0; nr_phys_segs = 0; + no_sg_merge = test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags); + high = 0; for_each_bio(bio) { bio_for_each_segment(bv, bio, iter) { /* + * If SG merging is disabled, each bio vector is + * a segment + */ + if (no_sg_merge) + goto new_segment; + + /* * the trick here is making sure that a high page is - * never considered part of another segment, since that - * might change with the bounce page. + * never considered part of another segment, since + * that might change with the bounce page. */ high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q); if (!high && !highprv && cluster) { @@ -84,11 +93,16 @@ void blk_recalc_rq_segments(struct request *rq) void blk_recount_segments(struct request_queue *q, struct bio *bio) { - struct bio *nxt = bio->bi_next; + if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags)) + 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); + bio->bi_next = nxt; + } - bio->bi_next = NULL; - bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio); - bio->bi_next = nxt; bio->bi_flags |= (1 << BIO_SEG_VALID); } EXPORT_SYMBOL(blk_recount_segments); diff --git a/block/blk-mq.c b/block/blk-mq.c index f27fe44230c..f98d977fd15 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1829,6 +1829,9 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) q->mq_ops = set->ops; q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; + if (!(set->flags & BLK_MQ_F_SG_MERGE)) + q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE; + q->sg_reserved_size = INT_MAX; INIT_WORK(&q->requeue_work, blk_mq_requeue_work); diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 91dfb75ce39..95de239444d 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -129,6 +129,7 @@ enum { BLK_MQ_F_SHOULD_MERGE = 1 << 0, BLK_MQ_F_SHOULD_SORT = 1 << 1, BLK_MQ_F_TAG_SHARED = 1 << 2, + BLK_MQ_F_SG_MERGE = 1 << 3, BLK_MQ_S_STOPPED = 0, BLK_MQ_S_TAG_ACTIVE = 1, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 098304576d5..695b9fd41ef 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -510,6 +510,7 @@ struct request_queue { #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */ #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */ #define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */ +#define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ |