[PATCH] device-mapper: tidy dm_suspend

Tidy dm_suspend.

Signed-Off-By: Alasdair G Kergon <agk@redhat.com>
From: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 23 insertions, 20 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 83f53a46c2d4..f6b03957efc7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1048,20 +1048,16 @@ int dm_suspend(struct mapped_device *md)
 {
         struct dm_table *map;
         DECLARE_WAITQUEUE(wait, current);
-        int error;
+        int error = -EINVAL;
 
         /* Flush I/O to the device. */
         down_read(&md->lock);
-        if (test_bit(DMF_BLOCK_IO, &md->flags)) {
-                up_read(&md->lock);
-                return -EINVAL;
-        }
+        if (test_bit(DMF_BLOCK_IO, &md->flags))
+                goto out_read_unlock;
 
         error = __lock_fs(md);
-        if (error) {
-                up_read(&md->lock);
-                return error;
-        }
+        if (error)
+                goto out_read_unlock;
 
         map = dm_get_table(md);
         if (map)
@@ -1075,15 +1071,14 @@ int dm_suspend(struct mapped_device *md)
          * 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.
          */
+        error = -EINVAL;
         down_write(&md->lock);
-        if (test_bit(DMF_BLOCK_IO, &md->flags)) {
-                up_write(&md->lock);
+        if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
                 if (map)
                         dm_table_put(map);
-                return -EINVAL;
+                goto out_write_unlock;
         }
 
-        set_bit(DMF_BLOCK_IO, &md->flags);
         add_wait_queue(&md->wait, &wait);
         up_write(&md->lock);
 
@@ -1111,13 +1106,9 @@ int dm_suspend(struct mapped_device *md)
         remove_wait_queue(&md->wait, &wait);
 
         /* were we interrupted ? */
-        if (atomic_read(&md->pending)) {
-                /* FIXME Undo the presuspend_targets */
-                __unlock_fs(md);
-                clear_bit(DMF_BLOCK_IO, &md->flags);
-                up_write(&md->lock);
-                return -EINTR;
-        }
+        error = -EINTR;
+        if (atomic_read(&md->pending))
+                goto out_unfreeze;
 
         set_bit(DMF_SUSPENDED, &md->flags);
 
@@ -1128,6 +1119,18 @@ int dm_suspend(struct mapped_device *md)
         up_write(&md->lock);
 
         return 0;
+
+out_unfreeze:
+        /* FIXME Undo dm_table_presuspend_targets */
+        __unlock_fs(md);
+        clear_bit(DMF_BLOCK_IO, &md->flags);
+out_write_unlock:
+        up_write(&md->lock);
+        return error;
+
+out_read_unlock:
+        up_read(&md->lock);
+        return error;
 }
 
 int dm_resume(struct mapped_device *md)