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Commit c7329eff authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
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dm crypt: use wake_up_process() instead of a wait queue 



This is a small simplification of dm-crypt - use wake_up_process()
instead of a wait queue in a case where only one process may be
waiting.  dm-writecache uses a similar pattern.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent a3fcf725

drivers/md/dm-crypt.c

+10 −15
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ struct crypt_config { 
	struct workqueue_struct *io_queue;

	struct workqueue_struct *crypt_queue;



	wait_queue_head_t write_thread_wait;

	spinlock_t write_thread_lock;

	struct task_struct *write_thread;

	struct rb_root write_tree;
@@ -1620,36 +1620,31 @@ static int dmcrypt_write(void *data) 
		struct rb_root write_tree;

		struct blk_plug plug;



		DECLARE_WAITQUEUE(wait, current);



		spin_lock_irq(&cc->write_thread_wait.lock);

		spin_lock_irq(&cc->write_thread_lock);

continue_locked:



		if (!RB_EMPTY_ROOT(&cc->write_tree))

			goto pop_from_list;



		set_current_state(TASK_INTERRUPTIBLE);

		__add_wait_queue(&cc->write_thread_wait, &wait);



		spin_unlock_irq(&cc->write_thread_wait.lock);

		spin_unlock_irq(&cc->write_thread_lock);



		if (unlikely(kthread_should_stop())) {

			set_current_state(TASK_RUNNING);

			remove_wait_queue(&cc->write_thread_wait, &wait);

			break;

		}



		schedule();



		set_current_state(TASK_RUNNING);

		spin_lock_irq(&cc->write_thread_wait.lock);

		__remove_wait_queue(&cc->write_thread_wait, &wait);

		spin_lock_irq(&cc->write_thread_lock);

		goto continue_locked;



pop_from_list:

		write_tree = cc->write_tree;

		cc->write_tree = RB_ROOT;

		spin_unlock_irq(&cc->write_thread_wait.lock);

		spin_unlock_irq(&cc->write_thread_lock);



		BUG_ON(rb_parent(write_tree.rb_node));
@@ -1693,7 +1688,9 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 
		return;

	}



	spin_lock_irqsave(&cc->write_thread_wait.lock, flags);

	spin_lock_irqsave(&cc->write_thread_lock, flags);

	if (RB_EMPTY_ROOT(&cc->write_tree))

		wake_up_process(cc->write_thread);

	rbp = &cc->write_tree.rb_node;

	parent = NULL;

	sector = io->sector;
@@ -1706,9 +1703,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) 
	}

	rb_link_node(&io->rb_node, parent, rbp);

	rb_insert_color(&io->rb_node, &cc->write_tree);



	wake_up_locked(&cc->write_thread_wait);

	spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);

	spin_unlock_irqrestore(&cc->write_thread_lock, flags);

}



static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
@@ -2831,7 +2826,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
		goto bad;

	}



	init_waitqueue_head(&cc->write_thread_wait);

	spin_lock_init(&cc->write_thread_lock);

	cc->write_tree = RB_ROOT;



	cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");