From bd6737f1ae92e2f1c6e8362efe96dbe7f18fa07d Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Fri, 27 Jan 2017 01:00:47 -0700
Subject: [PATCH] blk-mq-sched: add flush insertion into
blk_mq_sched_insert_request()
Instead of letting the caller check this and handle the details
of inserting a flush request, put the logic in the scheduler
insertion function. This fixes direct flush insertion outside
of the usual make_request_fn calls, like from dm via
blk_insert_cloned_request().
Signed-off-by: Jens Axboe <axboe@fb.com>
---
block/blk-core.c | 2 +-
block/blk-exec.c | 2 +-
block/blk-flush.c | 2 +-
block/blk-mq-sched.c | 58 ++++++++++++++++++++++++++++++++++++++++++++
block/blk-mq-sched.h | 45 +++++-----------------------------
block/blk-mq-tag.c | 8 +++++-
block/blk-mq.c | 25 ++++++++++---------
block/blk-mq.h | 2 ++
8 files changed, 89 insertions(+), 55 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index b830e14117ddd..4bfd8674afd03 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2129,7 +2129,7 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
if (q->mq_ops) {
if (blk_queue_io_stat(q))
blk_account_io_start(rq, true);
- blk_mq_sched_insert_request(rq, false, true, false);
+ blk_mq_sched_insert_request(rq, false, true, false, false);
return 0;
}
diff --git a/block/blk-exec.c b/block/blk-exec.c
index 86656fdfa6378..ed1f101652688 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -66,7 +66,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
* be reused after dying flag is set
*/
if (q->mq_ops) {
- blk_mq_sched_insert_request(rq, at_head, true, false);
+ blk_mq_sched_insert_request(rq, at_head, true, false, false);
return;
}
diff --git a/block/blk-flush.c b/block/blk-flush.c
index d7de34ee39c20..4427896641ac7 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -456,7 +456,7 @@ void blk_insert_flush(struct request *rq)
if ((policy & REQ_FSEQ_DATA) &&
!(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) {
if (q->mq_ops)
- blk_mq_sched_insert_request(rq, false, true, false);
+ blk_mq_sched_insert_request(rq, false, true, false, false);
else
list_add_tail(&rq->queuelist, &q->queue_head);
return;
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 4139b07ab33bd..1112752f888d0 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -335,6 +335,64 @@ void blk_mq_sched_restart_queues(struct blk_mq_hw_ctx *hctx)
}
}
+/*
+ * Add flush/fua to the queue. If we fail getting a driver tag, then
+ * punt to the requeue list. Requeue will re-invoke us from a context
+ * that's safe to block from.
+ */
+static void blk_mq_sched_insert_flush(struct blk_mq_hw_ctx *hctx,
+ struct request *rq, bool can_block)
+{
+ if (blk_mq_get_driver_tag(rq, &hctx, can_block)) {
+ blk_insert_flush(rq);
+ blk_mq_run_hw_queue(hctx, true);
+ } else
+ blk_mq_add_to_requeue_list(rq, true, true);
+}
+
+void blk_mq_sched_insert_request(struct request *rq, bool at_head,
+ bool run_queue, bool async, bool can_block)
+{
+ struct request_queue *q = rq->q;
+ struct elevator_queue *e = q->elevator;
+ struct blk_mq_ctx *ctx = rq->mq_ctx;
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
+
+ if (rq->tag == -1 && (rq->cmd_flags & (REQ_PREFLUSH | REQ_FUA))) {
+ blk_mq_sched_insert_flush(hctx, rq, can_block);
+ return;
+ }
+
+ if (e && e->type->ops.mq.insert_requests) {
+ LIST_HEAD(list);
+
+ list_add(&rq->queuelist, &list);
+ e->type->ops.mq.insert_requests(hctx, &list, at_head);
+ } else {
+ spin_lock(&ctx->lock);
+ __blk_mq_insert_request(hctx, rq, at_head);
+ spin_unlock(&ctx->lock);
+ }
+
+ if (run_queue)
+ blk_mq_run_hw_queue(hctx, async);
+}
+
+void blk_mq_sched_insert_requests(struct request_queue *q,
+ struct blk_mq_ctx *ctx,
+ struct list_head *list, bool run_queue_async)
+{
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
+ struct elevator_queue *e = hctx->queue->elevator;
+
+ if (e && e->type->ops.mq.insert_requests)
+ e->type->ops.mq.insert_requests(hctx, list, false);
+ else
+ blk_mq_insert_requests(hctx, ctx, list);
+
+ blk_mq_run_hw_queue(hctx, run_queue_async);
+}
+
static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx *hctx,
unsigned int hctx_idx)
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index becbc78403643..9478aaeb48c59 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -21,6 +21,12 @@ bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio);
bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq);
void blk_mq_sched_restart_queues(struct blk_mq_hw_ctx *hctx);
+void blk_mq_sched_insert_request(struct request *rq, bool at_head,
+ bool run_queue, bool async, bool can_block);
+void blk_mq_sched_insert_requests(struct request_queue *q,
+ struct blk_mq_ctx *ctx,
+ struct list_head *list, bool run_queue_async);
+
void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx);
void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
struct list_head *rq_list,
@@ -62,45 +68,6 @@ static inline void blk_mq_sched_put_rq_priv(struct request_queue *q,
e->type->ops.mq.put_rq_priv(q, rq);
}
-static inline void
-blk_mq_sched_insert_request(struct request *rq, bool at_head, bool run_queue,
- bool async)
-{
- struct request_queue *q = rq->q;
- struct elevator_queue *e = q->elevator;
- struct blk_mq_ctx *ctx = rq->mq_ctx;
- struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
-
- if (e && e->type->ops.mq.insert_requests) {
- LIST_HEAD(list);
-
- list_add(&rq->queuelist, &list);
- e->type->ops.mq.insert_requests(hctx, &list, at_head);
- } else {
- spin_lock(&ctx->lock);
- __blk_mq_insert_request(hctx, rq, at_head);
- spin_unlock(&ctx->lock);
- }
-
- if (run_queue)
- blk_mq_run_hw_queue(hctx, async);
-}
-
-static inline void
-blk_mq_sched_insert_requests(struct request_queue *q, struct blk_mq_ctx *ctx,
- struct list_head *list, bool run_queue_async)
-{
- struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
- struct elevator_queue *e = hctx->queue->elevator;
-
- if (e && e->type->ops.mq.insert_requests)
- e->type->ops.mq.insert_requests(hctx, list, false);
- else
- blk_mq_insert_requests(hctx, ctx, list);
-
- blk_mq_run_hw_queue(hctx, run_queue_async);
-}
-
static inline bool
blk_mq_sched_allow_merge(struct request_queue *q, struct request *rq,
struct bio *bio)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index f8de2dbbb29fc..54c84363c1b23 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -106,6 +106,7 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
struct sbq_wait_state *ws;
DEFINE_WAIT(wait);
unsigned int tag_offset;
+ bool drop_ctx;
int tag;
if (data->flags & BLK_MQ_REQ_RESERVED) {
@@ -128,6 +129,7 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
return BLK_MQ_TAG_FAIL;
ws = bt_wait_ptr(bt, data->hctx);
+ drop_ctx = data->ctx == NULL;
do {
prepare_to_wait(&ws->wait, &wait, TASK_UNINTERRUPTIBLE);
@@ -150,7 +152,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
if (tag != -1)
break;
- blk_mq_put_ctx(data->ctx);
+ if (data->ctx)
+ blk_mq_put_ctx(data->ctx);
io_schedule();
@@ -166,6 +169,9 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
ws = bt_wait_ptr(bt, data->hctx);
} while (1);
+ if (drop_ctx && data->ctx)
+ blk_mq_put_ctx(data->ctx);
+
finish_wait(&ws->wait, &wait);
found_tag:
diff --git a/block/blk-mq.c b/block/blk-mq.c
index da2123dd681e3..60dac10228fe0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -568,13 +568,13 @@ static void blk_mq_requeue_work(struct work_struct *work)
rq->rq_flags &= ~RQF_SOFTBARRIER;
list_del_init(&rq->queuelist);
- blk_mq_sched_insert_request(rq, true, false, false);
+ blk_mq_sched_insert_request(rq, true, false, false, true);
}
while (!list_empty(&rq_list)) {
rq = list_entry(rq_list.next, struct request, queuelist);
list_del_init(&rq->queuelist);
- blk_mq_sched_insert_request(rq, false, false, false);
+ blk_mq_sched_insert_request(rq, false, false, false, true);
}
blk_mq_run_hw_queues(q, false);
@@ -847,12 +847,11 @@ static inline unsigned int queued_to_index(unsigned int queued)
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
}
-static bool blk_mq_get_driver_tag(struct request *rq,
- struct blk_mq_hw_ctx **hctx, bool wait)
+bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
+ bool wait)
{
struct blk_mq_alloc_data data = {
.q = rq->q,
- .ctx = rq->mq_ctx,
.hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu),
.flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
};
@@ -1395,7 +1394,7 @@ static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie)
}
insert:
- blk_mq_sched_insert_request(rq, false, true, true);
+ blk_mq_sched_insert_request(rq, false, true, true, false);
}
/*
@@ -1446,10 +1445,12 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
cookie = request_to_qc_t(data.hctx, rq);
if (unlikely(is_flush_fua)) {
+ blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
blk_mq_get_driver_tag(rq, NULL, true);
blk_insert_flush(rq);
- goto run_queue;
+ blk_mq_run_hw_queue(data.hctx, true);
+ goto done;
}
plug = current->plug;
@@ -1502,7 +1503,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
blk_mq_sched_insert_request(rq, false, true,
- !is_sync || is_flush_fua);
+ !is_sync || is_flush_fua, true);
goto done;
}
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
@@ -1512,7 +1513,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
* latter allows for merging opportunities and more efficient
* dispatching.
*/
-run_queue:
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
}
blk_mq_put_ctx(data.ctx);
@@ -1568,10 +1568,12 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
cookie = request_to_qc_t(data.hctx, rq);
if (unlikely(is_flush_fua)) {
+ blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
blk_mq_get_driver_tag(rq, NULL, true);
blk_insert_flush(rq);
- goto run_queue;
+ blk_mq_run_hw_queue(data.hctx, true);
+ goto done;
}
/*
@@ -1612,7 +1614,7 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
blk_mq_sched_insert_request(rq, false, true,
- !is_sync || is_flush_fua);
+ !is_sync || is_flush_fua, true);
goto done;
}
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
@@ -1622,7 +1624,6 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
* latter allows for merging opportunities and more efficient
* dispatching.
*/
-run_queue:
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
}
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 077a4003f1fd0..57cdbf6c0cee9 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -34,6 +34,8 @@ void blk_mq_wake_waiters(struct request_queue *q);
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *, struct list_head *);
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx);
+bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
+ bool wait);
/*
* Internal helpers for allocating/freeing the request map
--
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