USB: usb-skeleton.c: fix compilation error and restored kref_put on fail in skel_open

Fixing compilaton error.
Incrementing usage counter only on successful execution of skel_open.
Removing redundant locking

Some last changes in function skel_open and finally commit
52a7499 Revert "USB: usb-skeleton.c: fix open/disconnect race"
introduced a bug in function skel_open, which this patch fixes.

Changes since v2:
- refactoring
- Removing redundant mutex synchronization.

Changes since v1:
- Fixed accordingly feedback of Oliver Neukum oneukum@suse.de: also need to drop the lock.

Signed-off-by: Constantine Shulyupin <const@MakeLinux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 9 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 0616f235bd6b..ce310170829f 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -105,20 +105,15 @@ static int skel_open(struct inode *inode, struct file *file)
                 goto exit;
         }
 
-        /* increment our usage count for the device */
-        kref_get(&dev->kref);
-
-        /* lock the device to allow correctly handling errors
-         * in resumption */
-        mutex_lock(&dev->io_mutex);
-
         retval = usb_autopm_get_interface(interface);
         if (retval)
-                goto out_err;
+                goto exit;
+
+        /* increment our usage count for the device */
+        kref_get(&dev->kref);
 
         /* save our object in the file's private structure */
         file->private_data = dev;
-        mutex_unlock(&dev->io_mutex);
 
 exit:
         return retval;