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Commit b8dcdab3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus-20180825' of git://git.kernel.dk/linux-block 

Pull block fixes from Jens Axboe:
 "A few small fixes for this merge window:

   - Locking imbalance fix for bcache (Shan Hai)

   - A few small fixes for wbt. One is a cleanup/prep, one is a fix for
     an existing issue, and the last two are fixes for changes that went
     into this merge window (me)"

* tag 'for-linus-20180825' of git://git.kernel.dk/linux-block:
  blk-wbt: don't maintain inflight counts if disabled
  blk-wbt: fix has-sleeper queueing check
  blk-wbt: use wq_has_sleeper() for wq active check
  blk-wbt: move disable check into get_limit()
  bcache: release dc->writeback_lock properly in bch_writeback_thread()
parents db84abf5 c125311d

block/blk-sysfs.c

+18 −1
Original line number Diff line number Diff line
@@ -453,9 +453,26 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page, 
	else if (val >= 0)

		val *= 1000ULL;



	wbt_set_min_lat(q, val);

	/*

	 * Ensure that the queue is idled, in case the latency update

	 * ends up either enabling or disabling wbt completely. We can't

	 * have IO inflight if that happens.

	 */

	if (q->mq_ops) {

		blk_mq_freeze_queue(q);

		blk_mq_quiesce_queue(q);

	} else

		blk_queue_bypass_start(q);



	wbt_set_min_lat(q, val);

	wbt_update_limits(q);



	if (q->mq_ops) {

		blk_mq_unquiesce_queue(q);

		blk_mq_unfreeze_queue(q);

	} else

		blk_queue_bypass_end(q);



	return count;

}

block/blk-wbt.c

+17 −20
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ static void rwb_wake_all(struct rq_wb *rwb) 
	for (i = 0; i < WBT_NUM_RWQ; i++) {

		struct rq_wait *rqw = &rwb->rq_wait[i];



		if (waitqueue_active(&rqw->wait))

		if (wq_has_sleeper(&rqw->wait))

			wake_up_all(&rqw->wait);

	}

}
@@ -162,7 +162,7 @@ static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct) 
	if (inflight && inflight >= limit)

		return;



	if (waitqueue_active(&rqw->wait)) {

	if (wq_has_sleeper(&rqw->wait)) {

		int diff = limit - inflight;



		if (!inflight || diff >= rwb->wb_background / 2)
@@ -449,6 +449,13 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw) 
{

	unsigned int limit;



	/*

	 * If we got disabled, just return UINT_MAX. This ensures that

	 * we'll properly inc a new IO, and dec+wakeup at the end.

	 */

	if (!rwb_enabled(rwb))

		return UINT_MAX;



	if ((rw & REQ_OP_MASK) == REQ_OP_DISCARD)

		return rwb->wb_background;
@@ -485,31 +492,17 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, 
{

	struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);

	DECLARE_WAITQUEUE(wait, current);

	bool has_sleeper;



	/*

	* inc it here even if disabled, since we'll dec it at completion.

	* this only happens if the task was sleeping in __wbt_wait(),

	* and someone turned it off at the same time.

	*/

	if (!rwb_enabled(rwb)) {

		atomic_inc(&rqw->inflight);

		return;

	}



	if (!waitqueue_active(&rqw->wait)

		&& rq_wait_inc_below(rqw, get_limit(rwb, rw)))

	has_sleeper = wq_has_sleeper(&rqw->wait);

	if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))

		return;



	add_wait_queue_exclusive(&rqw->wait, &wait);

	do {

		set_current_state(TASK_UNINTERRUPTIBLE);



		if (!rwb_enabled(rwb)) {

			atomic_inc(&rqw->inflight);

			break;

		}



		if (rq_wait_inc_below(rqw, get_limit(rwb, rw)))

		if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))

			break;



		if (lock) {
@@ -518,6 +511,7 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, 
			spin_lock_irq(lock);

		} else

			io_schedule();

		has_sleeper = false;

	} while (1);



	__set_current_state(TASK_RUNNING);
@@ -546,6 +540,9 @@ static enum wbt_flags bio_to_wbt_flags(struct rq_wb *rwb, struct bio *bio) 
{

	enum wbt_flags flags = 0;



	if (!rwb_enabled(rwb))

		return 0;



	if (bio_op(bio) == REQ_OP_READ) {

		flags = WBT_READ;

	} else if (wbt_should_throttle(rwb, bio)) {

drivers/md/bcache/writeback.c

+3 −1
Original line number Diff line number Diff line
@@ -685,9 +685,11 @@ static int bch_writeback_thread(void *arg) 
			 * data on cache. BCACHE_DEV_DETACHING flag is set in

			 * bch_cached_dev_detach().

			 */

			if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))

			if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) {

				up_write(&dc->writeback_lock);

				break;

			}

		}



		up_write(&dc->writeback_lock);