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 EF67FC433EF for ; Mon, 11 Jul 2022 17:19:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229654AbiGKRTL (ORCPT ); Mon, 11 Jul 2022 13:19:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231453AbiGKRTJ (ORCPT ); Mon, 11 Jul 2022 13:19:09 -0400 Received: from mail-io1-xd31.google.com (mail-io1-xd31.google.com [IPv6:2607:f8b0:4864:20::d31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA62727160 for ; Mon, 11 Jul 2022 10:19:08 -0700 (PDT) Received: by mail-io1-xd31.google.com with SMTP id l24so5518794ion.13 for ; Mon, 11 Jul 2022 10:19:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=P/ZbOGRCMUCwsXJG1pP78JzJo4IAGqfVhKppLMaFBWM=; b=ZvTDraTPKziHCNOQfWr+33ekuim54lUPDbYxXKWE2zr0fyQjO4WKqYkf3iF4BtILw0 VCqoW7E1KY3LOO1pTxYJ0SYrEUR++FL1cvVe+wvPBQUMYBFLPamH0VxWeH9EjxJVFNBm PJqUZtKL31NeUDwxCf4YJALbx4UYvgc3qfGgp3KqsclFq1wYPD5OWXhJUDvHkZgJoyaa NLbfin+YjfJAljGQ+F/veGiiTsDFYJccaJb7kWBNbd5aixAPtSoR/njWyKYmHVromzCI skH31e9ZZVQsBAVszOxqpFPqGMXXBwvnQlmSCASQEpzMStCHzL9g8lqUV8hcJBu9uDD+ xnew== 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 :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=P/ZbOGRCMUCwsXJG1pP78JzJo4IAGqfVhKppLMaFBWM=; b=pnlhC3fUjeLmVBHiyVfL6wVwIgonHm4xvHUB5AIMt9Ttc/6r66QKAZZfgZxSTIedV3 NZ1SIgRnyJFlggdfPE92vVHiXAjTocSztesijE2Xq+jjsMMNiYfd8GP5Kolcx163hzZe v92cvrOmls7ALiwrjDJNi/pDm8mDIKaBTmU1b6aj1DVFxxAJQmBc9Ygn12Y2ETIict7P NbbqAU7e/zArmsITxM0uICepxejRMFRgBeRvJmNvWU43ejtMab/lQ8gdB57ozi9ZDPAQ wTZCkYJuHxLPTevuXem/uzIQE7IG0JekvZO6rc8DiIaq3ERLsB5FJMFlxB1a2t7lK34h kbYQ== X-Gm-Message-State: AJIora8swKOqxNgS2U1RbolYEeP4bzyESb02Po4WbyNbNJLHYs7qZQTv Z7NpvQiqH4BrCL1bj7SfdmcynA== X-Google-Smtp-Source: AGRyM1u0yeGaTkXY9HASGmsozNj1TOs2lYBlJZY0JUhajLVF/LQwTS5mu+PGSzQEJeHVH30LiVqwJg== X-Received: by 2002:a02:c942:0:b0:339:ec11:d04e with SMTP id u2-20020a02c942000000b00339ec11d04emr10943258jao.174.1657559948356; Mon, 11 Jul 2022 10:19:08 -0700 (PDT) Received: from [192.168.1.172] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id 11-20020a92180b000000b002dc3a66b4b7sm2923791ily.33.2022.07.11.10.19.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Jul 2022 10:19:07 -0700 (PDT) Message-ID: <7ce5175e-c4dc-3af1-e47a-5966a999fdfe@kernel.dk> Date: Mon, 11 Jul 2022 11:19:07 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH for-next 3/4] io_uring: grow a field in struct io_uring_cmd Content-Language: en-US To: Sagi Grimberg , Kanchan Joshi , hch@lst.de, kbusch@kernel.org Cc: io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, asml.silence@gmail.com, joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com References: <20220711110155.649153-1-joshi.k@samsung.com> <20220711110155.649153-4-joshi.k@samsung.com> <11db8ab2-b41a-967e-8653-7a84b8a984c0@grimberg.me> From: Jens Axboe In-Reply-To: <11db8ab2-b41a-967e-8653-7a84b8a984c0@grimberg.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 7/11/22 11:00 AM, Sagi Grimberg wrote: > >> Use the leftover space to carve 'next' field that enables linking of >> io_uring_cmd structs. Also introduce a list head and few helpers. >> >> This is in preparation to support nvme-mulitpath, allowing multiple >> uring passthrough commands to be queued. >> >> Signed-off-by: Kanchan Joshi >> Signed-off-by: Anuj Gupta >> --- >>   include/linux/io_uring.h | 38 ++++++++++++++++++++++++++++++++++++-- >>   1 file changed, 36 insertions(+), 2 deletions(-) >> >> diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h >> index 54063d67506b..d734599cbcd7 100644 >> --- a/include/linux/io_uring.h >> +++ b/include/linux/io_uring.h >> @@ -22,9 +22,14 @@ struct io_uring_cmd { >>       const void    *cmd; >>       /* callback to defer completions to task context */ >>       void (*task_work_cb)(struct io_uring_cmd *cmd); >> +    struct io_uring_cmd    *next; >>       u32        cmd_op; >> -    u32        pad; >> -    u8        pdu[32]; /* available inline for free use */ >> +    u8        pdu[28]; /* available inline for free use */ >> +}; > > I think io_uring_cmd will at some point become two cachelines and may > not be worth the effort to limit a pdu to 28 bytes... -- Jens Axboe