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Commit 9b25bd03 authored by Paolo Valente's avatar Paolo Valente Committed by Jens Axboe
Browse files

block, bfq: remove batches of confusing ifdefs 

Commit a33801e8 ("block, bfq: move debug blkio stats behind
CONFIG_DEBUG_BLK_CGROUP") introduced two batches of confusing ifdefs:
one reported in [1], plus a similar one in another function. This
commit removes both batches, in the way suggested in [1].

[1] https://www.spinics.net/lists/linux-block/msg20043.html



Fixes: a33801e8 ("block, bfq: move debug blkio stats behind CONFIG_DEBUG_BLK_CGROUP")
Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Tested-by: default avatarLuca Miccio <lucmiccio@gmail.com>
Signed-off-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a34b0244

block/bfq-iosched.c

+72 −55
Original line number Diff line number Diff line
@@ -3743,35 +3743,16 @@ static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) 
	return rq;

}



static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)

{

	struct bfq_data *bfqd = hctx->queue->elevator->elevator_data;

	struct request *rq;

#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	struct bfq_queue *in_serv_queue, *bfqq;

	bool waiting_rq, idle_timer_disabled;

#endif



	spin_lock_irq(&bfqd->lock);



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	in_serv_queue = bfqd->in_service_queue;

	waiting_rq = in_serv_queue && bfq_bfqq_wait_request(in_serv_queue);



	rq = __bfq_dispatch_request(hctx);



	idle_timer_disabled =

		waiting_rq && !bfq_bfqq_wait_request(in_serv_queue);



#else

	rq = __bfq_dispatch_request(hctx);

#endif

	spin_unlock_irq(&bfqd->lock);

static void bfq_update_dispatch_stats(struct request_queue *q,

				      struct request *rq,

				      struct bfq_queue *in_serv_queue,

				      bool idle_timer_disabled)

{

	struct bfq_queue *bfqq = rq ? RQ_BFQQ(rq) : NULL;



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	bfqq = rq ? RQ_BFQQ(rq) : NULL;

	if (!idle_timer_disabled && !bfqq)

		return rq;

		return;



	/*

	 * rq and bfqq are guaranteed to exist until this function
@@ -3786,7 +3767,7 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) 
	 * In addition, the following queue lock guarantees that

	 * bfqq_group(bfqq) exists as well.

	 */

	spin_lock_irq(hctx->queue->queue_lock);

	spin_lock_irq(q->queue_lock);

	if (idle_timer_disabled)

		/*

		 * Since the idle timer has been disabled,
@@ -3805,9 +3786,37 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) 
		bfqg_stats_set_start_empty_time(bfqg);

		bfqg_stats_update_io_remove(bfqg, rq->cmd_flags);

	}

	spin_unlock_irq(hctx->queue->queue_lock);

	spin_unlock_irq(q->queue_lock);

}

#else

static inline void bfq_update_dispatch_stats(struct request_queue *q,

					     struct request *rq,

					     struct bfq_queue *in_serv_queue,

					     bool idle_timer_disabled) {}

#endif



static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)

{

	struct bfq_data *bfqd = hctx->queue->elevator->elevator_data;

	struct request *rq;

	struct bfq_queue *in_serv_queue;

	bool waiting_rq, idle_timer_disabled;



	spin_lock_irq(&bfqd->lock);



	in_serv_queue = bfqd->in_service_queue;

	waiting_rq = in_serv_queue && bfq_bfqq_wait_request(in_serv_queue);



	rq = __bfq_dispatch_request(hctx);



	idle_timer_disabled =

		waiting_rq && !bfq_bfqq_wait_request(in_serv_queue);



	spin_unlock_irq(&bfqd->lock);



	bfq_update_dispatch_stats(hctx->queue, rq, in_serv_queue,

				  idle_timer_disabled);



	return rq;

}
@@ -4335,16 +4344,46 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) 
	return idle_timer_disabled;

}



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

static void bfq_update_insert_stats(struct request_queue *q,

				    struct bfq_queue *bfqq,

				    bool idle_timer_disabled,

				    unsigned int cmd_flags)

{

	if (!bfqq)

		return;



	/*

	 * bfqq still exists, because it can disappear only after

	 * either it is merged with another queue, or the process it

	 * is associated with exits. But both actions must be taken by

	 * the same process currently executing this flow of

	 * instructions.

	 *

	 * In addition, the following queue lock guarantees that

	 * bfqq_group(bfqq) exists as well.

	 */

	spin_lock_irq(q->queue_lock);

	bfqg_stats_update_io_add(bfqq_group(bfqq), bfqq, cmd_flags);

	if (idle_timer_disabled)

		bfqg_stats_update_idle_time(bfqq_group(bfqq));

	spin_unlock_irq(q->queue_lock);

}

#else

static inline void bfq_update_insert_stats(struct request_queue *q,

					   struct bfq_queue *bfqq,

					   bool idle_timer_disabled,

					   unsigned int cmd_flags) {}

#endif



static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,

			       bool at_head)

{

	struct request_queue *q = hctx->queue;

	struct bfq_data *bfqd = q->elevator->elevator_data;

#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	struct bfq_queue *bfqq = RQ_BFQQ(rq);

	bool idle_timer_disabled = false;

	unsigned int cmd_flags;

#endif



	spin_lock_irq(&bfqd->lock);

	if (blk_mq_sched_try_insert_merge(q, rq)) {
@@ -4363,7 +4402,6 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 
		else

			list_add_tail(&rq->queuelist, &bfqd->dispatch);

	} else {

#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

		idle_timer_disabled = __bfq_insert_request(bfqd, rq);

		/*

		 * Update bfqq, because, if a queue merge has occurred
@@ -4371,9 +4409,6 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 
		 * redirected into a new queue.

		 */

		bfqq = RQ_BFQQ(rq);

#else

		__bfq_insert_request(bfqd, rq);

#endif



		if (rq_mergeable(rq)) {

			elv_rqhash_add(q, rq);
@@ -4382,35 +4417,17 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 
		}

	}



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	/*

	 * Cache cmd_flags before releasing scheduler lock, because rq

	 * may disappear afterwards (for example, because of a request

	 * merge).

	 */

	cmd_flags = rq->cmd_flags;

#endif



	spin_unlock_irq(&bfqd->lock);



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

	if (!bfqq)

		return;

	/*

	 * bfqq still exists, because it can disappear only after

	 * either it is merged with another queue, or the process it

	 * is associated with exits. But both actions must be taken by

	 * the same process currently executing this flow of

	 * instruction.

	 *

	 * In addition, the following queue lock guarantees that

	 * bfqq_group(bfqq) exists as well.

	 */

	spin_lock_irq(q->queue_lock);

	bfqg_stats_update_io_add(bfqq_group(bfqq), bfqq, cmd_flags);

	if (idle_timer_disabled)

		bfqg_stats_update_idle_time(bfqq_group(bfqq));

	spin_unlock_irq(q->queue_lock);

#endif

	bfq_update_insert_stats(q, bfqq, idle_timer_disabled,

				cmd_flags);

}



static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx,