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Commit b44ebeb0 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
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dm: move wait queue declaration 



Move wait queue declaration and unplug to dm_wait_for_completion.

The purpose is to minimize duplicate code in the further patches.

The patch reorders functions a little bit. It doesn't change any
functionality. For proper non-deadlock operation, add_wait_queue must
happen before set_current_state(interruptible) and before the test for
!atomic_read(&md->pending).

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 022c2611

drivers/md/dm.c

+7 −7
Original line number Diff line number Diff line
@@ -1377,6 +1377,11 @@ EXPORT_SYMBOL_GPL(dm_put); 
static int dm_wait_for_completion(struct mapped_device *md, int interruptible)

{

	int r = 0;

	DECLARE_WAITQUEUE(wait, current);



	dm_unplug_all(md->queue);



	add_wait_queue(&md->wait, &wait);



	while (1) {

		set_current_state(interruptible);
@@ -1395,6 +1400,8 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) 
	}

	set_current_state(TASK_RUNNING);



	remove_wait_queue(&md->wait, &wait);



	return r;

}
@@ -1501,7 +1508,6 @@ static void unlock_fs(struct mapped_device *md) 
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)

{

	struct dm_table *map = NULL;

	DECLARE_WAITQUEUE(wait, current);

	int r = 0;

	int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;

	int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
@@ -1551,20 +1557,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) 
	down_write(&md->io_lock);

	set_bit(DMF_BLOCK_IO, &md->flags);



	add_wait_queue(&md->wait, &wait);

	up_write(&md->io_lock);



	/* unplug */

	if (map)

		dm_table_unplug_all(map);



	/*

	 * Wait for the already-mapped ios to complete.

	 */

	r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);



	down_write(&md->io_lock);

	remove_wait_queue(&md->wait, &wait);



	if (noflush)

		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);