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block: remove non mq parts from the flush code 

Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2018-10-13 15:44:12 -06:00
parent 7ca0192646
commit 7e992f847a
2 changed files with 30 additions and 126 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

152
block/blk-flush.c
View File

@ -134,16 +134,8 @@ static void blk_flush_restore_request(struct request *rq)
static bool blk_flush_queue_rq(struct request *rq, bool add_front)
{
if (rq->q->mq_ops) {
blk_mq_add_to_requeue_list(rq, add_front, true);
return false;
} else {
if (add_front)
list_add(&rq->queuelist, &rq->q->queue_head);
else
list_add_tail(&rq->queuelist, &rq->q->queue_head);
return true;
}
blk_mq_add_to_requeue_list(rq, add_front, true);
return false;
}
/**
@ -204,10 +196,7 @@ static bool blk_flush_complete_seq(struct request *rq,
BUG_ON(!list_empty(&rq->queuelist));
list_del_init(&rq->flush.list);
blk_flush_restore_request(rq);
if (q->mq_ops)
blk_mq_end_request(rq, error);
else
__blk_end_request_all(rq, error);
blk_mq_end_request(rq, error);
break;
default:
@ -226,20 +215,17 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
struct request *rq, *n;
unsigned long flags = 0;
struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx);
struct blk_mq_hw_ctx *hctx;
if (q->mq_ops) {
struct blk_mq_hw_ctx *hctx;
/* release the tag's ownership to the req cloned from */
spin_lock_irqsave(&fq->mq_flush_lock, flags);
hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu);
if (!q->elevator) {
blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
flush_rq->tag = -1;
} else {
blk_mq_put_driver_tag_hctx(hctx, flush_rq);
flush_rq->internal_tag = -1;
}
/* release the tag's ownership to the req cloned from */
spin_lock_irqsave(&fq->mq_flush_lock, flags);
hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu);
if (!q->elevator) {
blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
flush_rq->tag = -1;
} else {
blk_mq_put_driver_tag_hctx(hctx, flush_rq);
flush_rq->internal_tag = -1;
}
running = &fq->flush_queue[fq->flush_running_idx];
@ -248,9 +234,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
/* account completion of the flush request */
fq->flush_running_idx ^= 1;
if (!q->mq_ops)
elv_completed_request(q, flush_rq);
/* and push the waiting requests to the next stage */
list_for_each_entry_safe(rq, n, running, flush.list) {
unsigned int seq = blk_flush_cur_seq(rq);
@ -259,24 +242,8 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
queued |= blk_flush_complete_seq(rq, fq, seq, error);
}
/*
* Kick the queue to avoid stall for two cases:
* 1. Moving a request silently to empty queue_head may stall the
* queue.
* 2. When flush request is running in non-queueable queue, the
* queue is hold. Restart the queue after flush request is finished
* to avoid stall.
* This function is called from request completion path and calling
* directly into request_fn may confuse the driver. Always use
* kblockd.
*/
if (queued || fq->flush_queue_delayed) {
WARN_ON(q->mq_ops);
blk_run_queue_async(q);
}
fq->flush_queue_delayed = 0;
if (q->mq_ops)
spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
}
/**
@ -301,6 +268,7 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
struct request *first_rq =
list_first_entry(pending, struct request, flush.list);
struct request *flush_rq = fq->flush_rq;
struct blk_mq_hw_ctx *hctx;
/* C1 described at the top of this file */
if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending))
@ -334,19 +302,15 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
* In case of IO scheduler, flush rq need to borrow scheduler tag
* just for cheating put/get driver tag.
*/
if (q->mq_ops) {
struct blk_mq_hw_ctx *hctx;
flush_rq->mq_ctx = first_rq->mq_ctx;
flush_rq->mq_ctx = first_rq->mq_ctx;
if (!q->elevator) {
fq->orig_rq = first_rq;
flush_rq->tag = first_rq->tag;
hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu);
blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq);
} else {
flush_rq->internal_tag = first_rq->internal_tag;
}
if (!q->elevator) {
fq->orig_rq = first_rq;
flush_rq->tag = first_rq->tag;
hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu);
blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq);
} else {
flush_rq->internal_tag = first_rq->internal_tag;
}
flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
@ -358,49 +322,6 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
return blk_flush_queue_rq(flush_rq, false);
}
static void flush_data_end_io(struct request *rq, blk_status_t error)
{
struct request_queue *q = rq->q;
struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
lockdep_assert_held(q->queue_lock);
/*
* Updating q->in_flight[] here for making this tag usable
* early. Because in blk_queue_start_tag(),
* q->in_flight[BLK_RW_ASYNC] is used to limit async I/O and
* reserve tags for sync I/O.
*
* More importantly this way can avoid the following I/O
* deadlock:
*
* - suppose there are 40 fua requests comming to flush queue
* and queue depth is 31
* - 30 rqs are scheduled then blk_queue_start_tag() can't alloc
* tag for async I/O any more
* - all the 30 rqs are completed before FLUSH_PENDING_TIMEOUT
* and flush_data_end_io() is called
* - the other rqs still can't go ahead if not updating
* q->in_flight[BLK_RW_ASYNC] here, meantime these rqs
* are held in flush data queue and make no progress of
* handling post flush rq
* - only after the post flush rq is handled, all these rqs
* can be completed
*/
elv_completed_request(q, rq);
/* for avoiding double accounting */
rq->rq_flags &= ~RQF_STARTED;
/*
* After populating an empty queue, kick it to avoid stall. Read
* the comment in flush_end_io().
*/
if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error))
blk_run_queue_async(q);
}
static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
{
struct request_queue *q = rq->q;
@ -443,9 +364,6 @@ void blk_insert_flush(struct request *rq)
unsigned int policy = blk_flush_policy(fflags, rq);
struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx);
if (!q->mq_ops)
lockdep_assert_held(q->queue_lock);
/*
* @policy now records what operations need to be done. Adjust
* REQ_PREFLUSH and FUA for the driver.
@ -468,10 +386,7 @@ void blk_insert_flush(struct request *rq)
* complete the request.
*/
if (!policy) {
if (q->mq_ops)
blk_mq_end_request(rq, 0);
else
__blk_end_request(rq, 0, 0);
blk_mq_end_request(rq, 0);
return;
}
@ -484,10 +399,7 @@ 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_request_bypass_insert(rq, false);
else
list_add_tail(&rq->queuelist, &q->queue_head);
blk_mq_request_bypass_insert(rq, false);
return;
}
@ -499,17 +411,12 @@ void blk_insert_flush(struct request *rq)
INIT_LIST_HEAD(&rq->flush.list);
rq->rq_flags |= RQF_FLUSH_SEQ;
rq->flush.saved_end_io = rq->end_io; /* Usually NULL */
if (q->mq_ops) {
rq->end_io = mq_flush_data_end_io;
spin_lock_irq(&fq->mq_flush_lock);
blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);
spin_unlock_irq(&fq->mq_flush_lock);
return;
}
rq->end_io = flush_data_end_io;
rq->end_io = mq_flush_data_end_io;
spin_lock_irq(&fq->mq_flush_lock);
blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);
spin_unlock_irq(&fq->mq_flush_lock);
}
/**
@ -575,8 +482,7 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
if (!fq)
goto fail;
if (q->mq_ops)
spin_lock_init(&fq->mq_flush_lock);
spin_lock_init(&fq->mq_flush_lock);
rq_sz = round_up(rq_sz + cmd_size, cache_line_size());
fq->flush_rq = kzalloc_node(rq_sz, flags, node);

4
block/blk.h
View File

@ -114,9 +114,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
static inline struct blk_flush_queue *blk_get_flush_queue(
struct request_queue *q, struct blk_mq_ctx *ctx)
{
if (q->mq_ops)
return blk_mq_map_queue(q, ctx->cpu)->fq;
return q->fq;
return blk_mq_map_queue(q, ctx->cpu)->fq;
}
static inline void __blk_get_queue(struct request_queue *q)