From 8de11cdc96bf58b324c59a28512eb9513fd02553 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 27 Oct 2022 07:44:28 -0700 Subject: io_uring: use io_run_local_work_locked helper prefer to use io_run_local_work_locked helper for consistency Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20221027144429.3971400-2-dylany@meta.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 6cc16e39b27f..8a0ce7379e89 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1446,8 +1446,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) io_task_work_pending(ctx)) { u32 tail = ctx->cached_cq_tail; - if (!llist_empty(&ctx->work_llist)) - __io_run_local_work(ctx, true); + (void) io_run_local_work_locked(ctx); if (task_work_pending(current) || wq_list_empty(&ctx->iopoll_list)) { -- cgit v1.2.3 From b3026767e15b488860d4bbf1649d69612bab2c25 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 27 Oct 2022 07:44:29 -0700 Subject: io_uring: unlock if __io_run_local_work locked inside It is possible for tw to lock the ring, and this was not propogated out to io_run_local_work. This can cause an unlock to be missed. Instead pass a pointer to locked into __io_run_local_work. Fixes: 8ac5d85a89b4 ("io_uring: add local task_work run helper that is entered locked") Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20221027144429.3971400-3-dylany@meta.com [axboe: WARN_ON() -> WARN_ON_ONCE() and add a minor comment] Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 8 ++++---- io_uring/io_uring.h | 13 +++++++++++-- 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 8a0ce7379e89..ac8c488e3077 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1173,7 +1173,7 @@ static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx) } } -int __io_run_local_work(struct io_ring_ctx *ctx, bool locked) +int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked) { struct llist_node *node; struct llist_node fake; @@ -1192,7 +1192,7 @@ again: struct io_kiocb *req = container_of(node, struct io_kiocb, io_task_work.node); prefetch(container_of(next, struct io_kiocb, io_task_work.node)); - req->io_task_work.func(req, &locked); + req->io_task_work.func(req, locked); ret++; node = next; } @@ -1208,7 +1208,7 @@ again: goto again; } - if (locked) + if (*locked) io_submit_flush_completions(ctx); trace_io_uring_local_work_run(ctx, ret, loops); return ret; @@ -1225,7 +1225,7 @@ int io_run_local_work(struct io_ring_ctx *ctx) __set_current_state(TASK_RUNNING); locked = mutex_trylock(&ctx->uring_lock); - ret = __io_run_local_work(ctx, locked); + ret = __io_run_local_work(ctx, &locked); if (locked) mutex_unlock(&ctx->uring_lock); diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index ef77d2aa3172..e99a79f2df9b 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -27,7 +27,7 @@ enum { struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow); bool io_req_cqe_overflow(struct io_kiocb *req); int io_run_task_work_sig(struct io_ring_ctx *ctx); -int __io_run_local_work(struct io_ring_ctx *ctx, bool locked); +int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked); int io_run_local_work(struct io_ring_ctx *ctx); void io_req_complete_failed(struct io_kiocb *req, s32 res); void __io_req_complete(struct io_kiocb *req, unsigned issue_flags); @@ -277,9 +277,18 @@ static inline int io_run_task_work_ctx(struct io_ring_ctx *ctx) static inline int io_run_local_work_locked(struct io_ring_ctx *ctx) { + bool locked; + int ret; + if (llist_empty(&ctx->work_llist)) return 0; - return __io_run_local_work(ctx, true); + + locked = true; + ret = __io_run_local_work(ctx, &locked); + /* shouldn't happen! */ + if (WARN_ON_ONCE(!locked)) + mutex_lock(&ctx->uring_lock); + return ret; } static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked) -- cgit v1.2.3