From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: * X-Spam-Status: No, score=1.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_SOFTFAIL autolearn=no autolearn_force=no version=3.4.6 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89B41C433EF for ; Thu, 21 Apr 2022 13:45:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354829AbiDUNsD (ORCPT ); Thu, 21 Apr 2022 09:48:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1386686AbiDUNsC (ORCPT ); Thu, 21 Apr 2022 09:48:02 -0400 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0C73B1C3 for ; Thu, 21 Apr 2022 06:45:12 -0700 (PDT) Received: by mail-wm1-x332.google.com with SMTP id l62-20020a1c2541000000b0038e4570af2fso3432236wml.5 for ; Thu, 21 Apr 2022 06:45:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=KEvqRy0N9PclazQqew6MevxkU4I4mKDIT57s+2Dre5A=; b=kp0V/sM4Ip142L3rdZ3bIWaFuG76xsRy/vQE0St/pkES9Dp3qFdm3virATzuJNcY/R dLRqpDtNfR3SH07vqrV9ghuaUoDimDwpS8AhdL1EM9yZZU9+28YV/dC3ekri8CXbEIDu NAZnqDpcMwq/Ea14ipoAZNp2Mrls8EI+sL7IbXxLXCdfTDVI9d5r95tlpNEAp+hxJyW8 at9IKavVGD4x/7sAEEHquV54ZlGwEcUWp42AlZz7684CXndSL94ReOwW+457sezq4AYZ 267e7C8jedda3LejM53ufXnPY2OwKqMftgye5/u1dwrbvyZKkl07m8tnu6SMuD0BtAU6 HSew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KEvqRy0N9PclazQqew6MevxkU4I4mKDIT57s+2Dre5A=; b=sZlomqtEr3IhOURD+BvXl0in2YUgWtK+uEmrDlISUUMd/Buz4z4LYfVdEEyZwdKWBg 4KDPn0JA1NmhwWpV5/UyicbMkKdDxsNCsEnr2I6eBRQJXJHI6q1pK5iG0Nn+shU150Hf DGILBPkQcUK1cAVNG9+ACAzh75GulxD32PzBX92UBIVmC16NUOoxYHerUh0lFW8hCMak sYiJdYcKBbu3Lmm5wd560zyoFSKAsRl8vHhWh49MV4Hf2P7rdW7v2jZOnpUmWWVRYEuT B3S3xcoHT++A7w+Mc33FsuMg299q5TA2mqQYbnSfeaF0V5uHTAAgkD1Atj4s2Q92Ebbe SCmw== X-Gm-Message-State: AOAM5334S2W6+M+78yxoXUZuio4E5d6t/tsHKgTg3bXQZ9tczL7YOvMV 6tSHxWx4Fv12+VXVmFVipBKHl55VhRU= X-Google-Smtp-Source: ABdhPJx1MyNAemEzqgjjRapYesHeLeZ3QFpePFz/bs4lX4OU/gMJvKSNrSuHpiL05eEFeCIK2MTr9g== X-Received: by 2002:a05:600c:211:b0:38e:d0f2:8a3f with SMTP id 17-20020a05600c021100b0038ed0f28a3fmr8834148wmi.8.1650548711070; Thu, 21 Apr 2022 06:45:11 -0700 (PDT) Received: from 127.0.0.1localhost ([148.252.129.218]) by smtp.gmail.com with ESMTPSA id m7-20020adfe0c7000000b002060e7bbe49sm2837821wri.45.2022.04.21.06.45.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Apr 2022 06:45:10 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [RFC 03/11] io_uring: ban tw queue for exiting processes Date: Thu, 21 Apr 2022 14:44:16 +0100 Message-Id: <4c8fc40551c5b991fc6560cba2ffe37f47375a1e.1650548192.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org We rely on PF_EXITING and task_work infrastructure for preventing adding new task_work items to a dying task, which is a bit more convoluted than desired. Ban new tw items earlier in io_uring_cancel_generic() by relying on ->in_idle. io_req_task_work_add() will check the flag, set REQ_F_FAIL and push requests to the fallback path. task_work handlers will find it and cancel requests just as it was with PF_EXITING. Signed-off-by: Pavel Begunkov --- fs/io_uring.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 272a180ab7ee..ec5fe55ab265 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1306,7 +1306,7 @@ static inline void req_ref_get(struct io_kiocb *req) static inline bool io_should_fail_tw(struct io_kiocb *req) { - return unlikely(req->task->flags & PF_EXITING); + return unlikely(req->flags & REQ_F_FAIL); } static inline void io_submit_flush_completions(struct io_ring_ctx *ctx) @@ -2577,10 +2577,6 @@ static void tctx_task_work(struct callback_head *cb) } ctx_flush_and_put(ctx, &uring_locked); - - /* relaxed read is enough as only the task itself sets ->in_idle */ - if (unlikely(atomic_read(&tctx->in_idle))) - io_uring_drop_tctx_refs(current); } static void io_req_task_work_add(struct io_kiocb *req, bool priority) @@ -2600,6 +2596,9 @@ static void io_req_task_work_add(struct io_kiocb *req, bool priority) spin_lock_irqsave(&tctx->task_lock, flags); list = priority ? &tctx->prior_task_list : &tctx->task_list; wq_list_add_tail(&req->io_task_work.node, list); + if (unlikely(atomic_read(&tctx->in_idle))) + goto cancel_locked; + running = tctx->task_running; if (!running) tctx->task_running = true; @@ -2623,12 +2622,13 @@ static void io_req_task_work_add(struct io_kiocb *req, bool priority) } spin_lock_irqsave(&tctx->task_lock, flags); - tctx->task_running = false; +cancel_locked: node = wq_list_merge(&tctx->prior_task_list, &tctx->task_list); spin_unlock_irqrestore(&tctx->task_lock, flags); while (node) { req = container_of(node, struct io_kiocb, io_task_work.node); + req_set_fail(req); node = node->next; if (llist_add(&req->io_task_work.fallback_node, &req->ctx->fallback_llist)) @@ -10352,7 +10352,10 @@ static __cold void io_uring_cancel_generic(bool cancel_all, if (tctx->io_wq) io_wq_exit_start(tctx->io_wq); + spin_lock_irq(&tctx->task_lock); atomic_inc(&tctx->in_idle); + spin_unlock_irq(&tctx->task_lock); + do { io_uring_drop_tctx_refs(current); /* read completions before cancelations */ -- 2.36.0