[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>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 83f53a46c2d462b81b975c24d87de45f58dc932a..f6b03957efc7b8bbd70f28f8ca1230b95ffeb4a3 100644 (file)
--- 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)