From: Pavel Begunkov <asml.silence@gmail.com> mainline inclusion from mainline-v6.9-rc4 commit 92219afb980e01d88a1ac6d8fe01dcae255c4279 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ICJPON CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- We can run normal task_work without locking the ctx, however we try to lock anyway and most handlers prefer or require it locked. It might have been interesting to multi-submitter ring with high contention completing async read/write requests via task_work, however that will still need to go through io_req_complete_post() and potentially take the lock for rsrc node putting or some other case. In other words, it's hard to care about it, so alawys force the locking. The case described would also because of various io_uring caches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Tested-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/6ae858f2ef562e6ed9f13c60978c0d48926954ba.171079918... Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflicts: io_uring/io_uring.c [Context differences.] Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> Signed-off-by: Long Li <leo.lilong@huawei.com> --- io_uring/io_uring.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a52f5b93dec7..4d72b14d8c1a 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1213,8 +1213,9 @@ static unsigned int handle_tw_list(struct llist_node *node, if (req->ctx != *ctx) { ctx_flush_and_put(*ctx, ts); *ctx = req->ctx; - /* if not contended, grab and improve batching */ - ts->locked = mutex_trylock(&(*ctx)->uring_lock); + + ts->locked = true; + mutex_lock(&(*ctx)->uring_lock); percpu_ref_get(&(*ctx)->refs); } INDIRECT_CALL_2(req->io_task_work.func, @@ -1439,11 +1440,9 @@ static int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts, if (io_run_local_work_continue(ctx, ret, min_events)) goto again; - if (ts->locked) { - io_submit_flush_completions(ctx); - if (io_run_local_work_continue(ctx, ret, min_events)) - goto again; - } + io_submit_flush_completions(ctx); + if (io_run_local_work_continue(ctx, ret, min_events)) + goto again; trace_io_uring_local_work_run(ctx, ret, loops); return ret; @@ -1467,14 +1466,12 @@ static inline int io_run_local_work_locked(struct io_ring_ctx *ctx, static int io_run_local_work(struct io_ring_ctx *ctx, int min_events) { - struct io_tw_state ts = {}; + struct io_tw_state ts = { .locked = true }; int ret; - ts.locked = mutex_trylock(&ctx->uring_lock); + mutex_lock(&ctx->uring_lock); ret = __io_run_local_work(ctx, &ts, min_events); - if (ts.locked) - mutex_unlock(&ctx->uring_lock); - + mutex_unlock(&ctx->uring_lock); return ret; } -- 2.39.2