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 <duyuyang@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d467ba8..d23dcb4 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1308,14 +1308,21 @@
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)
{
- if (__cq_empty(cq))
- return -1;
+ struct lock_list * lock;
- *elem = cq->element[cq->front];
+ if (__cq_empty(cq))
+ return NULL;
+
+ 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 @@
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 @@
__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;
