linux-kernel - [PATCH V5 6/8] block: introduce .last_merge and .hash to blk_mq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170930112655.31451-7-ming.lei@redhat.com>
Date:   Sat, 30 Sep 2017 19:26:53 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Jens Axboe <axboe@...com>, linux-block@...r.kernel.org,
        Christoph Hellwig <hch@...radead.org>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com
Cc:     Bart Van Assche <bart.vanassche@...disk.com>,
        Laurence Oberman <loberman@...hat.com>,
        Paolo Valente <paolo.valente@...aro.org>,
        Oleksandr Natalenko <oleksandr@...alenko.name>,
        Tom Nguyen <tom81094@...il.com>, linux-kernel@...r.kernel.org,
        Omar Sandoval <osandov@...com>, Ming Lei <ming.lei@...hat.com>
Subject: [PATCH V5 6/8] block: introduce .last_merge and .hash to blk_mq_ctx

Prepare for supporting bio merge to sw queue if no
blk-mq io scheduler is taken.

Tested-by: Oleksandr Natalenko <oleksandr@...alenko.name>
Tested-by: Tom Nguyen <tom81094@...il.com>
Tested-by: Paolo Valente <paolo.valente@...aro.org>
Signed-off-by: Ming Lei <ming.lei@...hat.com>
---
 block/blk-mq.h   |  4 ++++
 block/blk.h      |  3 +++
 block/elevator.c | 22 +++++++++++++++++++---
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/block/blk-mq.h b/block/blk-mq.h
index 5bca6ce1f01d..85ea8615fecf 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -18,6 +18,10 @@ struct blk_mq_ctx {
 	unsigned long		rq_dispatched[2];
 	unsigned long		rq_merged;
 
+	/* bio merge via request hash table */
+	struct request		*last_merge;
+	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
+
 	/* incremented at completion time */
 	unsigned long		____cacheline_aligned_in_smp rq_completed[2];
 
diff --git a/block/blk.h b/block/blk.h
index eb3436d4a73f..fa4f232afc18 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -198,6 +198,9 @@ static inline struct request *rqhash_find(struct hlist_head *hash, sector_t offs
 	return NULL;
 }
 
+enum elv_merge elv_merge_ctx(struct request_queue *q, struct request **req,
+                struct bio *bio, struct blk_mq_ctx *ctx);
+
 void blk_insert_flush(struct request *rq);
 
 static inline struct request *__elv_next_request(struct request_queue *q)
diff --git a/block/elevator.c b/block/elevator.c
index 2424aea85393..0e13e5c18982 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -471,6 +471,13 @@ enum elv_merge elv_merge(struct request_queue *q, struct request **req,
 	return __elv_merge(q, req, bio, q->elevator->hash, q->last_merge);
 }
 
+enum elv_merge elv_merge_ctx(struct request_queue *q, struct request **req,
+		struct bio *bio, struct blk_mq_ctx *ctx)
+{
+	WARN_ON_ONCE(!q->mq_ops);
+	return __elv_merge(q, req, bio, ctx->hash, ctx->last_merge);
+}
+
 /*
  * Attempt to do an insertion back merge. Only check for the case where
  * we can append 'rq' to an existing request, so we can throw 'rq' away
@@ -516,16 +523,25 @@ void elv_merged_request(struct request_queue *q, struct request *rq,
 		enum elv_merge type)
 {
 	struct elevator_queue *e = q->elevator;
+	struct hlist_head *hash = e->hash;
+
+	/* we do bio merge on blk-mq sw queue */
+	if (q->mq_ops && !e) {
+		rq->mq_ctx->last_merge = rq;
+		hash = rq->mq_ctx->hash;
+		goto reposition;
+	}
+
+	q->last_merge = rq;
 
 	if (e->uses_mq && e->type->ops.mq.request_merged)
 		e->type->ops.mq.request_merged(q, rq, type);
 	else if (!e->uses_mq && e->type->ops.sq.elevator_merged_fn)
 		e->type->ops.sq.elevator_merged_fn(q, rq, type);
 
+ reposition:
 	if (type == ELEVATOR_BACK_MERGE)
-		elv_rqhash_reposition(q, rq);
-
-	q->last_merge = rq;
+		rqhash_reposition(hash, rq);
 }
 
 void elv_merge_requests(struct request_queue *q, struct request *rq,
-- 
2.9.5