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authorYuyang Du <duyuyang@gmail.com>2019-05-06 16:19:29 +0800
committerIngo Molnar <mingo@kernel.org>2019-06-03 11:55:46 +0200
commitc1661325597f68bc9e632c4fa9c86983d56fba4f (patch)
tree8f2b14e7b23a90373d7f2764b02c16b6783aa5e3 /kernel/locking
parentaa4807719e076bfb2dee9c96adf2c648e47d472f (diff)
downloadlinux-c1661325597f68bc9e632c4fa9c86983d56fba4f.tar.bz2
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>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c21
1 files changed, 13 insertions, 8 deletions
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;