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: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f570372..7867d90 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1377,6 +1377,11 @@
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 @@
}
set_current_state(TASK_RUNNING);
+ remove_wait_queue(&md->wait, &wait);
+
return r;
}
@@ -1501,7 +1508,6 @@
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 @@
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);