From c1661325597f68bc9e632c4fa9c86983d56fba4f Mon Sep 17 00:00:00 2001 From: Yuyang Du Date: Mon, 6 May 2019 16:19:29 +0800 Subject: locking/lockdep: Change the return type of __cq_dequeue() With the change, we can slightly adjust the code to iterate the queue in BFS search, which simplifies the code. No functional change. Signed-off-by: Yuyang Du Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bvanassche@acm.org Cc: frederic@kernel.org Cc: ming.lei@redhat.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190506081939.74287-14-duyuyang@gmail.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'kernel/locking') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index d467ba825dca..d23dcb47389e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1308,14 +1308,21 @@ static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem return 0; } -static inline int __cq_dequeue(struct circular_queue *cq, struct lock_list **elem) +/* + * Dequeue an element from the circular_queue, return a lock_list if + * the queue is not empty, or NULL if otherwise. + */ +static inline struct lock_list * __cq_dequeue(struct circular_queue *cq) { + struct lock_list * lock; + if (__cq_empty(cq)) - return -1; + return NULL; - *elem = cq->element[cq->front]; + lock = cq->element[cq->front]; cq->front = (cq->front + 1) & CQ_MASK; - return 0; + + return lock; } static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) @@ -1367,6 +1374,7 @@ static int __bfs(struct lock_list *source_entry, int forward) { struct lock_list *entry; + struct lock_list *lock; struct list_head *head; struct circular_queue *cq = &lock_cq; int ret = 1; @@ -1388,10 +1396,7 @@ static int __bfs(struct lock_list *source_entry, __cq_init(cq); __cq_enqueue(cq, source_entry); - while (!__cq_empty(cq)) { - struct lock_list *lock; - - __cq_dequeue(cq, &lock); + while ((lock = __cq_dequeue(cq))) { if (!lock->class) { ret = -2; -- cgit v1.2.3-55-g7522