From df3becde8d9dcaaf17a615009301479f8f9c6323 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 15 Apr 2022 22:08:30 +0100 Subject: [PATCH] io_uring: refactor lazy link fail Remove the lazy link fail logic from io_submit_sqe() and hide it into a helper. It simplifies the code and will be needed in next patches. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/6a68aca9cf4492132da1d7c8a09068b74aba3c65.1650056133.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 87 ++++++++++++++++++++++++++++----------------------- 1 file changed, 47 insertions(+), 40 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 04dedc37e285..cb7c3bc7c1b7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7705,7 +7705,44 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, return io_req_prep(req, sqe); } -static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, +static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe, + struct io_kiocb *req, int ret) +{ + struct io_ring_ctx *ctx = req->ctx; + struct io_submit_link *link = &ctx->submit_state.link; + struct io_kiocb *head = link->head; + + trace_io_uring_req_failed(sqe, ctx, req, ret); + + /* + * Avoid breaking links in the middle as it renders links with SQPOLL + * unusable. Instead of failing eagerly, continue assembling the link if + * applicable and mark the head with REQ_F_FAIL. The link flushing code + * should find the flag and handle the rest. + */ + req_fail_link_node(req, ret); + if (head && !(head->flags & REQ_F_FAIL)) + req_fail_link_node(head, -ECANCELED); + + if (!(req->flags & IO_REQ_LINK_FLAGS)) { + if (head) { + link->last->link = req; + link->head = NULL; + req = head; + } + io_queue_sqe_fallback(req); + return ret; + } + + if (head) + link->last->link = req; + else + link->head = req; + link->last = req; + return 0; +} + +static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe) __must_hold(&ctx->uring_lock) { @@ -7713,32 +7750,8 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, int ret; ret = io_init_req(ctx, req, sqe); - if (unlikely(ret)) { - trace_io_uring_req_failed(sqe, ctx, req, ret); - - /* fail even hard links since we don't submit */ - if (link->head) { - /* - * we can judge a link req is failed or cancelled by if - * REQ_F_FAIL is set, but the head is an exception since - * it may be set REQ_F_FAIL because of other req's failure - * so let's leverage req->cqe.res to distinguish if a head - * is set REQ_F_FAIL because of its failure or other req's - * failure so that we can set the correct ret code for it. - * init result here to avoid affecting the normal path. - */ - if (!(link->head->flags & REQ_F_FAIL)) - req_fail_link_node(link->head, -ECANCELED); - } else if (!(req->flags & IO_REQ_LINK_FLAGS)) { - /* - * the current req is a normal req, we should return - * error and thus break the submittion loop. - */ - io_req_complete_failed(req, ret); - return ret; - } - req_fail_link_node(req, ret); - } + if (unlikely(ret)) + return io_submit_fail_init(sqe, req, ret); /* don't need @sqe from now on */ trace_io_uring_submit_sqe(ctx, req, req->cqe.user_data, req->opcode, @@ -7753,25 +7766,19 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, * conditions are true (normal request), then just queue it. */ if (link->head) { - struct io_kiocb *head = link->head; - - if (!(req->flags & REQ_F_FAIL)) { - ret = io_req_prep_async(req); - if (unlikely(ret)) { - req_fail_link_node(req, ret); - if (!(head->flags & REQ_F_FAIL)) - req_fail_link_node(head, -ECANCELED); - } - } - trace_io_uring_link(ctx, req, head); + ret = io_req_prep_async(req); + if (unlikely(ret)) + return io_submit_fail_init(sqe, req, ret); + + trace_io_uring_link(ctx, req, link->head); link->last->link = req; link->last = req; if (req->flags & IO_REQ_LINK_FLAGS) return 0; - /* last request of a link, enqueue the link */ + /* last request of the link, flush it */ + req = link->head; link->head = NULL; - req = head; } else if (req->flags & IO_REQ_LINK_FLAGS) { link->head = req; link->last = req; -- 2.20.1