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authorBaolin Wang <baolin.wang@linux.alibaba.com>2020-08-28 10:52:54 +0800
committerJens Axboe <axboe@kernel.dk>2020-09-01 16:49:26 -0600
commit8e756373d7c8eb6f8876411bed45e4b1c736eb53 (patch)
treec9f78ad91bf8edc74709d9082d6755674c651309 /block/blk-merge.c
parent339b5a25c28c1d85afd0ce882f57962ad550bc6a (diff)
block: Move bio merge related functions into blk-merge.c
It's better to move bio merge related functions into blk-merge.c, which contains all merge related functions. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index f685d633bcc9..3aa2de57b57f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -11,6 +11,7 @@
#include <trace/events/block.h>
#include "blk.h"
+#include "blk-rq-qos.h"
static inline bool bio_will_gap(struct request_queue *q,
struct request *prev_rq, struct bio *prev, struct bio *next)
@@ -895,3 +896,159 @@ enum elv_merge blk_try_merge(struct request *rq, struct bio *bio)
return ELEVATOR_FRONT_MERGE;
return ELEVATOR_NO_MERGE;
}
+
+static void blk_account_io_merge_bio(struct request *req)
+{
+ if (!blk_do_io_stat(req))
+ return;
+
+ part_stat_lock();
+ part_stat_inc(req->part, merges[op_stat_group(req_op(req))]);
+ part_stat_unlock();
+}
+
+bool bio_attempt_back_merge(struct request *req, struct bio *bio,
+ unsigned int nr_segs)
+{
+ const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
+
+ if (!ll_back_merge_fn(req, bio, nr_segs))
+ return false;
+
+ trace_block_bio_backmerge(req->q, req, bio);
+ rq_qos_merge(req->q, req, bio);
+
+ if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
+ blk_rq_set_mixed_merge(req);
+
+ req->biotail->bi_next = bio;
+ req->biotail = bio;
+ req->__data_len += bio->bi_iter.bi_size;
+
+ bio_crypt_free_ctx(bio);
+
+ blk_account_io_merge_bio(req);
+ return true;
+}
+
+bool bio_attempt_front_merge(struct request *req, struct bio *bio,
+ unsigned int nr_segs)
+{
+ const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
+
+ if (!ll_front_merge_fn(req, bio, nr_segs))
+ return false;
+
+ trace_block_bio_frontmerge(req->q, req, bio);
+ rq_qos_merge(req->q, req, bio);
+
+ if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
+ blk_rq_set_mixed_merge(req);
+
+ bio->bi_next = req->bio;
+ req->bio = bio;
+
+ req->__sector = bio->bi_iter.bi_sector;
+ req->__data_len += bio->bi_iter.bi_size;
+
+ bio_crypt_do_front_merge(req, bio);
+
+ blk_account_io_merge_bio(req);
+ return true;
+}
+
+bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
+ struct bio *bio)
+{
+ unsigned short segments = blk_rq_nr_discard_segments(req);
+
+ if (segments >= queue_max_discard_segments(q))
+ goto no_merge;
+ if (blk_rq_sectors(req) + bio_sectors(bio) >
+ blk_rq_get_max_sectors(req, blk_rq_pos(req)))
+ goto no_merge;
+
+ rq_qos_merge(q, req, bio);
+
+ req->biotail->bi_next = bio;
+ req->biotail = bio;
+ req->__data_len += bio->bi_iter.bi_size;
+ req->nr_phys_segments = segments + 1;
+
+ blk_account_io_merge_bio(req);
+ return true;
+no_merge:
+ req_set_nomerge(q, req);
+ return false;
+}
+
+/**
+ * blk_attempt_plug_merge - try to merge with %current's plugged list
+ * @q: request_queue new bio is being queued at
+ * @bio: new bio being queued
+ * @nr_segs: number of segments in @bio
+ * @same_queue_rq: pointer to &struct request that gets filled in when
+ * another request associated with @q is found on the plug list
+ * (optional, may be %NULL)
+ *
+ * Determine whether @bio being queued on @q can be merged with a request
+ * on %current's plugged list. Returns %true if merge was successful,
+ * otherwise %false.
+ *
+ * Plugging coalesces IOs from the same issuer for the same purpose without
+ * going through @q->queue_lock. As such it's more of an issuing mechanism
+ * than scheduling, and the request, while may have elvpriv data, is not
+ * added on the elevator at this point. In addition, we don't have
+ * reliable access to the elevator outside queue lock. Only check basic
+ * merging parameters without querying the elevator.
+ *
+ * Caller must ensure !blk_queue_nomerges(q) beforehand.
+ */
+bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
+ unsigned int nr_segs, struct request **same_queue_rq)
+{
+ struct blk_plug *plug;
+ struct request *rq;
+ struct list_head *plug_list;
+
+ plug = blk_mq_plug(q, bio);
+ if (!plug)
+ return false;
+
+ plug_list = &plug->mq_list;
+
+ list_for_each_entry_reverse(rq, plug_list, queuelist) {
+ bool merged = false;
+
+ if (rq->q == q && same_queue_rq) {
+ /*
+ * Only blk-mq multiple hardware queues case checks the
+ * rq in the same queue, there should be only one such
+ * rq in a queue
+ **/
+ *same_queue_rq = rq;
+ }
+
+ if (rq->q != q || !blk_rq_merge_ok(rq, bio))
+ continue;
+
+ switch (blk_try_merge(rq, bio)) {
+ case ELEVATOR_BACK_MERGE:
+ merged = bio_attempt_back_merge(rq, bio, nr_segs);
+ break;
+ case ELEVATOR_FRONT_MERGE:
+ merged = bio_attempt_front_merge(rq, bio, nr_segs);
+ break;
+ case ELEVATOR_DISCARD_MERGE:
+ merged = bio_attempt_discard_merge(q, rq, bio);
+ break;
+ default:
+ break;
+ }
+
+ if (merged)
+ return true;
+ }
+
+ return false;
+}