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Commit 11b751ae authored by Ingo Molnar's avatar Ingo Molnar Committed by Ingo Molnar
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[PATCH] mutex subsystem, semaphore to completion: drivers/block/loop.c 



convert the block loop device from semaphores to completions.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f36d4024

drivers/block/loop.c

+12 −15
Original line number Diff line number Diff line
@@ -527,12 +527,12 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio) 
	lo->lo_pending++;

	loop_add_bio(lo, old_bio);

	spin_unlock_irq(&lo->lo_lock);

	up(&lo->lo_bh_mutex);

	complete(&lo->lo_bh_done);

	return 0;



out:

	if (lo->lo_pending == 0)

		up(&lo->lo_bh_mutex);

		complete(&lo->lo_bh_done);

	spin_unlock_irq(&lo->lo_lock);

	bio_io_error(old_bio, old_bio->bi_size);

	return 0;
@@ -593,23 +593,20 @@ static int loop_thread(void *data) 
	lo->lo_pending = 1;



	/*

	 * up sem, we are running

	 * complete it, we are running

	 */

	up(&lo->lo_sem);

	complete(&lo->lo_done);



	for (;;) {

		int pending;



		/*

		 * interruptible just to not contribute to load avg

		 */

		if (down_interruptible(&lo->lo_bh_mutex))

		if (wait_for_completion_interruptible(&lo->lo_bh_done))

			continue;



		spin_lock_irq(&lo->lo_lock);



		/*

		 * could be upped because of tear-down, not pending work

		 * could be completed because of tear-down, not pending work

		 */

		if (unlikely(!lo->lo_pending)) {

			spin_unlock_irq(&lo->lo_lock);
@@ -632,7 +629,7 @@ static int loop_thread(void *data) 
			break;

	}



	up(&lo->lo_sem);

	complete(&lo->lo_done);

	return 0;

}
@@ -843,7 +840,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, 
	set_blocksize(bdev, lo_blocksize);



	kernel_thread(loop_thread, lo, CLONE_KERNEL);

	down(&lo->lo_sem);

	wait_for_completion(&lo->lo_done);

	return 0;



 out_putf:
@@ -909,10 +906,10 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) 
	lo->lo_state = Lo_rundown;

	lo->lo_pending--;

	if (!lo->lo_pending)

		up(&lo->lo_bh_mutex);

		complete(&lo->lo_bh_done);

	spin_unlock_irq(&lo->lo_lock);



	down(&lo->lo_sem);

	wait_for_completion(&lo->lo_done);



	lo->lo_backing_file = NULL;
@@ -1289,8 +1286,8 @@ static int __init loop_init(void) 
		if (!lo->lo_queue)

			goto out_mem4;

		init_MUTEX(&lo->lo_ctl_mutex);

		init_MUTEX_LOCKED(&lo->lo_sem);

		init_MUTEX_LOCKED(&lo->lo_bh_mutex);

		init_completion(&lo->lo_done);

		init_completion(&lo->lo_bh_done);

		lo->lo_number = i;

		spin_lock_init(&lo->lo_lock);

		disk->major = LOOP_MAJOR;

include/linux/loop.h

+2 −2
Original line number Diff line number Diff line
@@ -58,9 +58,9 @@ struct loop_device { 
	struct bio 		*lo_bio;

	struct bio		*lo_biotail;

	int			lo_state;

	struct semaphore	lo_sem;

	struct completion	lo_done;

	struct completion	lo_bh_done;

	struct semaphore	lo_ctl_mutex;

	struct semaphore	lo_bh_mutex;

	int			lo_pending;



	request_queue_t		*lo_queue;