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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B4A3FC433F5 for ; Tue, 15 Mar 2022 08:57:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sbOTUaj4XuhiPBp35MM71d+BOt+rDxjEICtrwnWLUp0=; b=gdEGZAgsIMDgDL1Gd8QW2AHo/5 3RoWipxZNvymb9pY/jKurLLy0VWIeTxSHfaWOPDkbOnu/ttALd8vbKLe4BUF4KfxNY4UNXjXHejxK /uaeFsE3xvqKEVe2hAWvOSch8ZAhsufAdSsMepk3u/W1uU8SPsNocA9lKGdSE+pnKMmf9D4Pelq6x TIEeFxbAdDxjmn+5MpFgXti1q76PjSpBZp7zkefc8DI3uZBXkwFLwr1E/8lyOO5lUJQxlMPtOx++t MCG7MyUqKaUQARdq+LqYHrSNnp4etC6El9yWNM17c1LwlEuU4ClwqTeenD0uaaXuZVKU5orwThqRO J8UOe37g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nU309-008O8f-8h; Tue, 15 Mar 2022 08:57:57 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nU300-008O49-R6 for linux-nvme@lists.infradead.org; Tue, 15 Mar 2022 08:57:50 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 11FEF68AA6; Tue, 15 Mar 2022 09:57:46 +0100 (CET) Date: Tue, 15 Mar 2022 09:57:45 +0100 From: Christoph Hellwig To: Kanchan Joshi Cc: Christoph Hellwig , Kanchan Joshi , Jens Axboe , Keith Busch , Pavel Begunkov , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, sbates@raithlin.com, logang@deltatee.com, Pankaj Raghav , Javier =?iso-8859-1?Q?Gonz=E1lez?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta Subject: Re: [PATCH 14/17] io_uring: add polling support for uring-cmd Message-ID: <20220315085745.GE4132@lst.de> References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-15-joshi.k@samsung.com> <20220311065007.GC17728@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220315_015749_046547_AB19C9A2 X-CRM114-Status: GOOD ( 13.67 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Mar 14, 2022 at 03:46:08PM +0530, Kanchan Joshi wrote: > But, after you did bio based polling, we need just the bio to poll. > iocb is a big structure (48 bytes), and if we try to place it in > struct io_uring_cmd, we will just blow up the cacheline in io_uring > (first one in io_kiocb). > So we just store that bio pointer in io_uring_cmd on submission > (please see patch 15). > And here on completion we pick that bio, and put that into this local > iocb, simply because ->iopoll needs it. > Do you see I am still missing anything here? Yes. The VFS layer interface for polling is the kiocb. Don't break it. The bio is just an implementation detail.