Commit-ID: c1661325597f68bc9e632c4fa9c86983d56fba4f
Gitweb: https://git.kernel.org/tip/c1661325597f68bc9e632c4fa9c86983d56fba4f
Author: Yuyang Du <duyuyang@xxxxxxxxx>
AuthorDate: Mon, 6 May 2019 16:19:29 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 3 Jun 2019 11:55:46 +0200
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@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: bvanassche@xxxxxxx
Cc: frederic@xxxxxxxxxx
Cc: ming.lei@xxxxxxxxxx
Cc: will.deacon@xxxxxxx
Link: https://lkml.kernel.org/r/20190506081939.74287-14-duyuyang@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/locking/lockdep.c | 21 +++++++++++++--------
1 file 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;
|