loop: Push loop_ctl_mutex down to loop_change_fd()

Push loop_ctl_mutex down to loop_change_fd(). We will need this to be
able to call loop_reread_partitions() without loop_ctl_mutex.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 161e2a08f2e8dd59f70e4595017e0aae221eed17..ea5e313908b1462b6807a3a28314851bf2746f44 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -691,19 +691,22 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
        struct file     *file, *old_file;
        int             error;
 
+       error = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+       if (error)
+               return error;
        error = -ENXIO;
        if (lo->lo_state != Lo_bound)
-               goto out;
+               goto out_unlock;
 
        /* the loop device has to be read-only */
        error = -EINVAL;
        if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
-               goto out;
+               goto out_unlock;
 
        error = -EBADF;
        file = fget(arg);
        if (!file)
-               goto out;
+               goto out_unlock;
 
        error = loop_validate_file(file, bdev);
        if (error)
@@ -730,11 +733,13 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
        fput(old_file);
        if (lo->lo_flags & LO_FLAGS_PARTSCAN)
                loop_reread_partitions(lo, bdev);
+       mutex_unlock(&loop_ctl_mutex);
        return 0;
 
- out_putf:
+out_putf:
        fput(file);
- out:
+out_unlock:
+       mutex_unlock(&loop_ctl_mutex);
        return error;
 }
 
@@ -1469,12 +1474,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
        case LOOP_SET_FD:
                return loop_set_fd(lo, mode, bdev, arg);
        case LOOP_CHANGE_FD:
-               err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
-               if (err)
-                       return err;
-               err = loop_change_fd(lo, bdev, arg);
-               mutex_unlock(&loop_ctl_mutex);
-               break;
+               return loop_change_fd(lo, bdev, arg);
        case LOOP_CLR_FD:
                return loop_clr_fd(lo);
        case LOOP_SET_STATUS: