[tip:core/rcu] userfaultfd: Replace spin_is_locked() with lockdep

[tip-bot for Lance Roy <tipbot@zytor.com>]

Commit-ID:  456a737896b25e4853bbf3d6ca5a1c8ee4df4ee9
Gitweb:     https://git.kernel.org/tip/456a737896b25e4853bbf3d6ca5a1c8ee4df4ee9
Author:     Lance Roy <ldr709@gmail.com>
AuthorDate: Thu, 4 Oct 2018 23:45:44 -0700
Committer:  Paul E. McKenney <paulmck@linux.ibm.com>
CommitDate: Mon, 12 Nov 2018 09:06:22 -0800

userfaultfd: Replace spin_is_locked() with lockdep

lockdep_assert_held() is better suited to checking locking requirements,
since it only checks if the current thread holds the lock regardless of
whether someone else does. This is also a step towards possibly removing
spin_is_locked().

Signed-off-by: Lance Roy <ldr709@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
 fs/userfaultfd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 356d2b8568c1..681881dc8a9d 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -926,7 +926,7 @@ static inline struct userfaultfd_wait_queue *find_userfault_in(
 	wait_queue_entry_t *wq;
 	struct userfaultfd_wait_queue *uwq;
 
-	VM_BUG_ON(!spin_is_locked(&wqh->lock));
+	lockdep_assert_held(&wqh->lock);
 
 	uwq = NULL;
 	if (!waitqueue_active(wqh))