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 6F629C433EF for ; Mon, 11 Jul 2022 17:00:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229618AbiGKRA5 (ORCPT ); Mon, 11 Jul 2022 13:00:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbiGKRA5 (ORCPT ); Mon, 11 Jul 2022 13:00:57 -0400 Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B62C248FA; Mon, 11 Jul 2022 10:00:56 -0700 (PDT) Received: by mail-wm1-f54.google.com with SMTP id n185so3382649wmn.4; Mon, 11 Jul 2022 10:00:56 -0700 (PDT) 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=oRVmx9bOllxl3kVjulrN4qiEWyIXLjdDXqd2F2vjPHA=; b=J3j1vZwpPz5WJUe9EVOv5OWPcqv0klsvEYePqqxee9pK7CR2WIpF5WWP3flT7QJu6j IXkPjKaLpA2oovTPOgLKjGVrSrYq6e3G85X+V6Wt//y3n3VBXeDW/zy4ufAosy4cppZJ poXKdnp0kBNHyyOizfeVkqX1di525PeZh/Yq2isLGk4WD/M3uDzuyVy3NHtGS+DGzRPJ mZkM4WpqXjyUf+45flyR+Gy0r1cdDGkTRvh0eyPVzOoAzaY2faxb15xf6Q0uJaMSvYsP mIFbUQPFxMEWrlIr39/b+o66nc5vlrg4vr/2QuVRVMIgLXZ+Mz7xz5YTGIfSptKI2cNb QmUQ== X-Gm-Message-State: AJIora9/XigAEIww1JGILwdyBNbAenbri4R6cm3wTP2/SL8HcP8s/idI udqHED3ke63W3qSwKKOWuSuccZUShhM= X-Google-Smtp-Source: AGRyM1vg+hOt68iw5r4yo5w1HrJm0Q9QpaeugSVcQ4WGNMMLtUlEwXoj/U8a580os9JSwUfwsq3fiw== X-Received: by 2002:a05:600c:1548:b0:3a1:95fc:aa42 with SMTP id f8-20020a05600c154800b003a195fcaa42mr16914667wmg.189.1657558855078; Mon, 11 Jul 2022 10:00:55 -0700 (PDT) Received: from [10.100.102.14] (46-117-125-14.bb.netvision.net.il. [46.117.125.14]) by smtp.gmail.com with ESMTPSA id r3-20020adfe683000000b0021b81855c1csm7411785wrm.27.2022.07.11.10.00.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Jul 2022 10:00:54 -0700 (PDT) Message-ID: <11db8ab2-b41a-967e-8653-7a84b8a984c0@grimberg.me> Date: Mon, 11 Jul 2022 20:00:52 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH for-next 3/4] io_uring: grow a field in struct io_uring_cmd Content-Language: en-US To: Kanchan Joshi , hch@lst.de, kbusch@kernel.org, axboe@kernel.dk 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> From: Sagi Grimberg In-Reply-To: <20220711110155.649153-4-joshi.k@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org > 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...