From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2D8EC433F5 for ; Sat, 7 May 2022 09:13:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383812AbiEGJQs (ORCPT ); Sat, 7 May 2022 05:16:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230191AbiEGJQs (ORCPT ); Sat, 7 May 2022 05:16:48 -0400 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AB403152E; Sat, 7 May 2022 02:13:02 -0700 (PDT) Received: by mail-pg1-x530.google.com with SMTP id l11so2427096pgt.13; Sat, 07 May 2022 02:13:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:to:cc:references :from:in-reply-to:content-transfer-encoding; bh=bV6Fic4FC7WhnbPqNw/owaN+8XIB8Y3rXX1tGv2mwJc=; b=KXjPj+DFEpZNOYusBws3oxjiy2Ifoo/09c8LCm5Zge3K/Su0UFdqDS0hj5fl5OvrfW uT4Aeym2wNHGL4HDuIz48Yd2wrgf7p0x/K+VAzpGuVLM0Lk8Q4rjGkf8LhdE3aTSYUib OxssIiJ5YhIF6L1hORr9s0NEkmMAhTCCLJGdeP6m5kGbc2a9LsVK4SuJM85CdywiPDhf ld6wwGm4CrV26jknvAZX2LeVToSeUHXTiKtmOgpH08P+PT7FkKSonITuovdVKaRXBT7O GOoFWZ9euC5SZoiR/lSvKL+zWHGEjXKHz+Wbx6aLJUErVdxA1h22tACfgFxU0HM7oMhh nuqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :to:cc:references:from:in-reply-to:content-transfer-encoding; bh=bV6Fic4FC7WhnbPqNw/owaN+8XIB8Y3rXX1tGv2mwJc=; b=LtNih2+RY0SroMAJlFtXVPMJr+TnWRGGW6OY7uViTguu00uidHqc9C3IZjS5p2K1NF 0h9ZUhzaNeZsd7xxu9eIs1sgXomaH2AhLiSNLYKCqxSUUCegZeZvfcNFpXlY6CrFI7ZT pUr6KLwp3oB0zQZYMmXhMxLvuaDOXGELtsXk6rUWaUSp7Xk1KelanDH4iosjUTWykoHV NrDUYU353K5+S0/B7QnL9+p6s7zW360j4m0ENCkHclf8OpQRocYTaTu48Sml5AFdDEgV JvHeoVcYUAKoep1nXLU2AJb0dQ9Eeco3l8hyYOvwznIJlCRCWMzW+jPilYKbsWn3b7Mm kRyA== X-Gm-Message-State: AOAM532c0tiKeFY+gjoR/PtLgDr7w7sQsSeQBGAzq30y03XPFFqtTMar wPTnd/mSRaGw02MVDgKRIdo= X-Google-Smtp-Source: ABdhPJxtll5dm9eFbbNc1DcqQW32XJOYp3JHlPUPkbuR11b9Ui8z8VJVQhsMGvYmHW7fZ7vkZjxlLA== X-Received: by 2002:a05:6a00:23ca:b0:50e:827:9253 with SMTP id g10-20020a056a0023ca00b0050e08279253mr7601346pfc.20.1651914781709; Sat, 07 May 2022 02:13:01 -0700 (PDT) Received: from [192.168.255.10] ([106.53.4.151]) by smtp.gmail.com with ESMTPSA id t12-20020a17090b018c00b001d92e2e5694sm8911919pjs.1.2022.05.07.02.12.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 07 May 2022 02:13:00 -0700 (PDT) Message-ID: <8917973f-7286-1023-ad85-9f3d57302dbc@gmail.com> Date: Sat, 7 May 2022 17:13:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 5/5] io_uring: implement multishot mode for accept To: Jens Axboe , io-uring@vger.kernel.org Cc: Pavel Begunkov , linux-kernel@vger.kernel.org References: <20220506070102.26032-1-haoxu.linux@gmail.com> <20220506070102.26032-6-haoxu.linux@gmail.com> From: Hao Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 在 2022/5/6 下午10:42, Jens Axboe 写道: > On 5/6/22 1:01 AM, Hao Xu wrote: >> diff --git a/fs/io_uring.c b/fs/io_uring.c >> index 0a83ecc457d1..9febe7774dc3 100644 >> --- a/fs/io_uring.c >> +++ b/fs/io_uring.c >> @@ -1254,6 +1254,7 @@ static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags); >> static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer); >> static void io_eventfd_signal(struct io_ring_ctx *ctx); >> static void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags); >> +static void io_poll_remove_entries(struct io_kiocb *req); >> >> static struct kmem_cache *req_cachep; >> >> @@ -5690,24 +5691,29 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags) >> static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) >> { >> struct io_accept *accept = &req->accept; >> + bool multishot; >> >> if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) >> return -EINVAL; >> - if (sqe->ioprio || sqe->len || sqe->buf_index) >> + if (sqe->len || sqe->buf_index) >> return -EINVAL; >> >> accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); >> accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2)); >> accept->flags = READ_ONCE(sqe->accept_flags); >> accept->nofile = rlimit(RLIMIT_NOFILE); >> + multishot = !!(READ_ONCE(sqe->ioprio) & IORING_ACCEPT_MULTISHOT); > > I tend to like: > > multishot = READ_ONCE(sqe->ioprio) & IORING_ACCEPT_MULTISHOT) != 0; > > as I think it's more readable. But I think we really want it ala: > > u16 poll_flags; > > poll_flags = READ_ONCE(sqe->ioprio); > if (poll_flags & ~IORING_ACCEPT_MULTISHOT) > return -EINVAL; > > ... > > to ensure that we can add more flags later, hence only accepting this > single flag right now. > > Do we need REQ_F_APOLL_MULTI_POLLED, or can we just store whether this > is a multishot request in struct io_accept? I think we can do it in this way, but it may be a bit inconvenient if we add other multishot OPCODE. With REQ_F_APOLL_MULTI_POLLED we can just check req->flags in the poll arming path, which keeps it op unrelated. > >> @@ -5760,7 +5774,35 @@ static int io_accept(struct io_kiocb *req, unsigned int issue_flags) >> ret = io_install_fixed_file(req, file, issue_flags, >> accept->file_slot - 1); >> } >> - __io_req_complete(req, issue_flags, ret, 0); >> + >> + if (req->flags & REQ_F_APOLL_MULTISHOT) { >> + if (ret >= 0) { >> + bool filled; >> + >> + spin_lock(&ctx->completion_lock); >> + filled = io_fill_cqe_aux(ctx, req->cqe.user_data, ret, >> + IORING_CQE_F_MORE); >> + io_commit_cqring(ctx); >> + spin_unlock(&ctx->completion_lock); >> + if (unlikely(!filled)) { >> + io_poll_clean(req); >> + return -ECANCELED; >> + } >> + io_cqring_ev_posted(ctx); >> + goto retry; >> + } else { >> + /* >> + * the apoll multishot req should handle poll >> + * cancellation by itself since the upper layer >> + * who called io_queue_sqe() cannot get errors >> + * happened here. >> + */ >> + io_poll_clean(req); >> + return ret; >> + } >> + } else { >> + __io_req_complete(req, issue_flags, ret, 0); >> + } >> return 0; >> } > > I'd probably just make that: > > if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { > __io_req_complete(req, issue_flags, ret, 0); > return 0; > } > if (ret >= 0) { > bool filled; > > spin_lock(&ctx->completion_lock); > filled = io_fill_cqe_aux(ctx, req->cqe.user_data, ret, > IORING_CQE_F_MORE); > io_commit_cqring(ctx); > spin_unlock(&ctx->completion_lock); > if (filled) { > io_cqring_ev_posted(ctx); > goto retry; > } > /* fall through to error case */ > ret = -ECANCELED; > } > > /* > * the apoll multishot req should handle poll > * cancellation by itself since the upper layer > * who called io_queue_sqe() cannot get errors > * happened here. > */ > io_poll_clean(req); > return ret; > > which I think is a lot easier to read and keeps the indentation at a > manageable level and reduces duplicate code. Great, thanks, it's better. >