| Message ID | 20220714173255.12987-1-ubizjak@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | epoll: Use try_cmpxchg in list_add_tail_lockless | expand |
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index e2daa940ebce..6705cb965fbe 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1065,7 +1065,7 @@ static inline bool list_add_tail_lockless(struct list_head *new, * added to the list from another CPU: the winner observes * new->next == new. */ - if (cmpxchg(&new->next, new, head) != new) + if (!try_cmpxchg(&new->next, &new, head)) return false; /*
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in list_add_tail_lockless. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> --- fs/eventpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)