Commit eed8c02e authored by Lukas Czerner's avatar Lukas Czerner Committed by Jens Axboe
Browse files

wait: add wait_event_lock_irq() interface 



New wait_event{_interruptible}_lock_irq{_cmd} macros added. This commit
moves the private wait_event_lock_irq() macro from MD to regular wait
includes, introduces new macro wait_event_lock_irq_cmd() instead of using
the old method with omitting cmd parameter which is ugly and makes a use
of new macros in the MD. It also introduces the _interruptible_ variant.

The use of new interface is when one have a special lock to protect data
structures used in the condition, or one also needs to invoke "cmd"
before putting it to sleep.

All new macros are expected to be called with the lock taken. The lock
is released before sleep and is reacquired afterwards. We will leave the
macro with the lock held.

Note to DM: IMO this should also fix theoretical race on waitqueue while
using simultaneously wait_event_lock_irq() and wait_event() because of
lack of locking around current state setting and wait queue removal.

Signed-off-by: default avatarLukas Czerner <lczerner@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d33b98fc

drivers/md/md.c

+1 −1
Original line number Diff line number Diff line
@@ -452,7 +452,7 @@ void md_flush_request(struct mddev *mddev, struct bio *bio) 
	spin_lock_irq(&mddev->write_lock);

	wait_event_lock_irq(mddev->sb_wait,

			    !mddev->flush_bio,

			    mddev->write_lock, /*nothing*/);

			    mddev->write_lock);

	mddev->flush_bio = bio;

	spin_unlock_irq(&mddev->write_lock);

drivers/md/md.h

+0 −26
Original line number Diff line number Diff line
@@ -551,32 +551,6 @@ struct md_thread { 


#define THREAD_WAKEUP  0



#define __wait_event_lock_irq(wq, condition, lock, cmd) 		\

do {									\

	wait_queue_t __wait;						\

	init_waitqueue_entry(&__wait, current);				\

									\

	add_wait_queue(&wq, &__wait);					\

	for (;;) {							\

		set_current_state(TASK_UNINTERRUPTIBLE);		\

		if (condition)						\

			break;						\

		spin_unlock_irq(&lock);					\

		cmd;							\

		schedule();						\

		spin_lock_irq(&lock);					\

	}								\

	current->state = TASK_RUNNING;					\

	remove_wait_queue(&wq, &__wait);				\

} while (0)



#define wait_event_lock_irq(wq, condition, lock, cmd) 			\

do {									\

	if (condition)	 						\

		break;							\

	__wait_event_lock_irq(wq, condition, lock, cmd);		\

} while (0)



static inline void safe_put_page(struct page *p)

{

	if (p) put_page(p);

drivers/md/raid1.c

+7 −8
Original line number Diff line number Diff line
@@ -822,7 +822,7 @@ static void raise_barrier(struct r1conf *conf) 


	/* Wait until no block IO is waiting */

	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,

			    conf->resync_lock, );

			    conf->resync_lock);



	/* block any new IO from starting */

	conf->barrier++;
@@ -830,7 +830,7 @@ static void raise_barrier(struct r1conf *conf) 
	/* Now wait for all pending IO to complete */

	wait_event_lock_irq(conf->wait_barrier,

			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,

			    conf->resync_lock, );

			    conf->resync_lock);



	spin_unlock_irq(&conf->resync_lock);

}
@@ -864,8 +864,7 @@ static void wait_barrier(struct r1conf *conf) 
				    (conf->nr_pending &&

				     current->bio_list &&

				     !bio_list_empty(current->bio_list)),

				    conf->resync_lock,

			);

				    conf->resync_lock);

		conf->nr_waiting--;

	}

	conf->nr_pending++;
@@ -898,7 +897,7 @@ static void freeze_array(struct r1conf *conf) 
	spin_lock_irq(&conf->resync_lock);

	conf->barrier++;

	conf->nr_waiting++;

	wait_event_lock_irq(conf->wait_barrier,

	wait_event_lock_irq_cmd(conf->wait_barrier,

				conf->nr_pending == conf->nr_queued+1,

				conf->resync_lock,

				flush_pending_writes(conf));

drivers/md/raid10.c

+7 −8
Original line number Diff line number Diff line
@@ -952,7 +952,7 @@ static void raise_barrier(struct r10conf *conf, int force) 


	/* Wait until no block IO is waiting (unless 'force') */

	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,

			    conf->resync_lock, );

			    conf->resync_lock);



	/* block any new IO from starting */

	conf->barrier++;
@@ -960,7 +960,7 @@ static void raise_barrier(struct r10conf *conf, int force) 
	/* Now wait for all pending IO to complete */

	wait_event_lock_irq(conf->wait_barrier,

			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,

			    conf->resync_lock, );

			    conf->resync_lock);



	spin_unlock_irq(&conf->resync_lock);

}
@@ -993,8 +993,7 @@ static void wait_barrier(struct r10conf *conf) 
				    (conf->nr_pending &&

				     current->bio_list &&

				     !bio_list_empty(current->bio_list)),

				    conf->resync_lock,

			);

				    conf->resync_lock);

		conf->nr_waiting--;

	}

	conf->nr_pending++;
@@ -1027,7 +1026,7 @@ static void freeze_array(struct r10conf *conf) 
	spin_lock_irq(&conf->resync_lock);

	conf->barrier++;

	conf->nr_waiting++;

	wait_event_lock_irq(conf->wait_barrier,

	wait_event_lock_irq_cmd(conf->wait_barrier,

				conf->nr_pending == conf->nr_queued+1,

				conf->resync_lock,

				flush_pending_writes(conf));

drivers/md/raid5.c

+5 −7
Original line number Diff line number Diff line
@@ -466,7 +466,7 @@ get_active_stripe(struct r5conf *conf, sector_t sector, 
	do {

		wait_event_lock_irq(conf->wait_for_stripe,

				    conf->quiesce == 0 || noquiesce,

				    conf->device_lock, /* nothing */);

				    conf->device_lock);

		sh = __find_stripe(conf, sector, conf->generation - previous);

		if (!sh) {

			if (!conf->inactive_blocked)
@@ -480,8 +480,7 @@ get_active_stripe(struct r5conf *conf, sector_t sector, 
						    (atomic_read(&conf->active_stripes)

						     < (conf->max_nr_stripes *3/4)

						     || !conf->inactive_blocked),

						    conf->device_lock,

						    );

						    conf->device_lock);

				conf->inactive_blocked = 0;

			} else

				init_stripe(sh, sector, previous);
@@ -1646,8 +1645,7 @@ static int resize_stripes(struct r5conf *conf, int newsize) 
		spin_lock_irq(&conf->device_lock);

		wait_event_lock_irq(conf->wait_for_stripe,

				    !list_empty(&conf->inactive_list),

				    conf->device_lock,

				    );

				    conf->device_lock);

		osh = get_free_stripe(conf);

		spin_unlock_irq(&conf->device_lock);

		atomic_set(&nsh->count, 1);
@@ -4000,7 +3998,7 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio) 
		spin_lock_irq(&conf->device_lock);

		wait_event_lock_irq(conf->wait_for_stripe,

				    conf->quiesce == 0,

				    conf->device_lock, /* nothing */);

				    conf->device_lock);

		atomic_inc(&conf->active_aligned_reads);

		spin_unlock_irq(&conf->device_lock);
@@ -6088,7 +6086,7 @@ static void raid5_quiesce(struct mddev *mddev, int state) 
		wait_event_lock_irq(conf->wait_for_stripe,

				    atomic_read(&conf->active_stripes) == 0 &&

				    atomic_read(&conf->active_aligned_reads) == 0,

				    conf->device_lock, /* nothing */);

				    conf->device_lock);

		conf->quiesce = 1;

		spin_unlock_irq(&conf->device_lock);

		/* allow reshape to continue */

CRA Git | Maintained and supported by SUSTech CRA and CCSE