IB/uverbs: Release lock on error path

If ibdev->alloc_ucontext() fails then ib_uverbs_get_context() does not
unlock file->mutex before returning error.

Signed-off by: Ganapathi CH <cganapathi@novell.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -80,8 +80,10 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
 		   in_len - sizeof cmd, out_len - sizeof resp);
 
 	ucontext = ibdev->alloc_ucontext(ibdev, &udata);
-	if (IS_ERR(ucontext))
-		return PTR_ERR(file->ucontext);
+	if (IS_ERR(ucontext)) {
+		ret = PTR_ERR(file->ucontext);
+		goto err;
+	}
 
 	ucontext->device = ibdev;
 	INIT_LIST_HEAD(&ucontext->pd_list);