From: Pavel Begunkov <asml.silence@gmail.com> mainline inclusion from mainline-5.9-rc1 commit 01cec8c18f5ad9c27eee9f21439072832181039e category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA --------------------------- If ->cq_timeouts modifications are done under ->completion_lock, we don't really nee any fetch-and-add and other complex atomics. Replace it with non-atomic FAA, that saves an implicit full memory barrier. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- fs/io_uring.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index cf6ecea9e5c3..1a35314a1045 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1269,7 +1269,8 @@ static void io_kill_timeout(struct io_kiocb *req) ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { - atomic_inc(&req->ctx->cq_timeouts); + atomic_set(&req->ctx->cq_timeouts, + atomic_read(&req->ctx->cq_timeouts) + 1); list_del_init(&req->timeout.list); req->flags |= REQ_F_COMP_LOCKED; io_cqring_fill_event(req, 0); @@ -4922,9 +4923,10 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) struct io_ring_ctx *ctx = req->ctx; unsigned long flags; - atomic_inc(&ctx->cq_timeouts); - spin_lock_irqsave(&ctx->completion_lock, flags); + atomic_set(&req->ctx->cq_timeouts, + atomic_read(&req->ctx->cq_timeouts) + 1); + /* * We could be racing with timeout deletion. If the list is empty, * then timeout lookup already found it and will be handling it. -- 2.25.1