Always use DMF_SUSPENDED instead of DMF_BLOCK_IO to detect suspension.
More dm_suspend tidying.
--- diff/drivers/md/dm.c	2005-07-06 19:35:16.000000000 +0100
+++ source/drivers/md/dm.c	2005-07-06 19:34:44.000000000 +0100
@@ -1041,7 +1041,7 @@
  */
 int dm_suspend(struct mapped_device *md)
 {
-	struct dm_table *map;
+	struct dm_table *map = NULL;
 	DECLARE_WAITQUEUE(wait, current);
 	int r = -EINVAL;
 
@@ -1050,45 +1050,28 @@
 	if (dm_suspended(md))
 		goto out;
 
-	/* Flush I/O to the device. */
-	down_read(&md->io_lock);
-	if (test_bit(DMF_BLOCK_IO, &md->flags))
-		goto out_read_unlock;
-
 	map = dm_get_table(md);
+
 	/* This does not get reverted if there's an error later. */
 	dm_table_presuspend_targets(map);
 
+	/* Flush I/O to the device. */
 	r = __lock_fs(md);
-	if (r) {
-		dm_table_put(map);
-		goto out_read_unlock;
-	}
-
-	up_read(&md->io_lock);
+	if (r)
+		goto out;
 
 	/*
 	 * First we set the BLOCK_IO flag so no more ios will be mapped.
-	 *
-	 * If the flag is already set we know another thread is trying to
-	 * suspend as well, so we leave the fs locked for this thread.
 	 */
-	r = -EINVAL;
 	down_write(&md->io_lock);
-	if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
-		if (map)
-			dm_table_put(map);
-		goto out_write_unlock;
-	}
+	set_bit(DMF_BLOCK_IO, &md->flags);
 
 	add_wait_queue(&md->wait, &wait);
 	up_write(&md->io_lock);
 
 	/* unplug */
-	if (map) {
+	if (map)
 		dm_table_unplug_all(map);
-		dm_table_put(map);
-	}
 
 	/*
 	 * Then we wait for the already mapped ios to
@@ -1109,31 +1092,22 @@
 
 	/* were we interrupted ? */
 	r = -EINTR;
-	if (atomic_read(&md->pending))
-		goto out_unfreeze;
-
-	set_bit(DMF_SUSPENDED, &md->flags);
+	if (atomic_read(&md->pending)) {
+		__unlock_fs(md);
+		clear_bit(DMF_BLOCK_IO, &md->flags);
+		up_write(&md->io_lock);
+		goto out;
+	}
+	up_write(&md->io_lock);
 
-	map = dm_get_table(md);
 	dm_table_postsuspend_targets(map);
-	dm_table_put(map);
-	up_write(&md->io_lock);
 
-	r = 0;
-out:
-	up_write(&md->suspend_lock);
-	return r;
+	set_bit(DMF_SUSPENDED, &md->flags);
 
-out_unfreeze:
-	__unlock_fs(md);
-	clear_bit(DMF_BLOCK_IO, &md->flags);
-out_write_unlock:
-	up_write(&md->io_lock);
-	up_write(&md->suspend_lock);
-	return r;
+	r = 0;
 
-out_read_unlock:
-	up_read(&md->io_lock);
+out:
+	dm_table_put(map);
 	up_write(&md->suspend_lock);
 	return r;
 }
@@ -1154,7 +1128,6 @@
 
 	down_write(&md->io_lock);
 	dm_table_resume_targets(map);
-	clear_bit(DMF_SUSPENDED, &md->flags);
 	clear_bit(DMF_BLOCK_IO, &md->flags);
 
 	def = bio_list_get(&md->deferred);
@@ -1163,6 +1136,8 @@
 
 	__unlock_fs(md);
 
+	clear_bit(DMF_SUSPENDED, &md->flags);
+
 	dm_table_unplug_all(map);
 
 	r = 0;