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 1EF51C77B72 for ; Thu, 20 Apr 2023 12:31:52 +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=yjHuZR1FiTy+CNjCS37PaZAWquM3kFyxRb+Dk2fFwZc=; b=lqRqDYuWHzW8p3jnZf1spsYg5M vNAfGedFQtBOT8YNTBGaDzQ1IVCdEB3L46GOzNlGCRqvhZAuqrxR4BfZBnATQ98Rm8LznmYqgeXL3 FBEyoK7hTi6e3YbGz/99adIuMIRT5gg1pzAPUFS2ye2CQ5syLMoa57S62TDa3eVAC+i9bxpkdQ7xS CndTE6DnChQYYWotFzSbLhNzJCae7ziimhVCsdT3OlX+/P05viy2ePcbpHvi0kdVxFjAsLkasIna+ kZ7z/jQR1+jH8EHqWVMup4ndbIafOkidDuR6+11jhwmWNN2r8w+8UOYYeyoDKUx2rP7Uu+xrUnvAk nVsazqhQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1ppTS2-0084Mq-1K; Thu, 20 Apr 2023 12:31:50 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1ppTRz-0084Kr-2L for linux-nvme@lists.infradead.org; Thu, 20 Apr 2023 12:31:49 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 7BF2B68AFE; Thu, 20 Apr 2023 14:31:39 +0200 (CEST) Date: Thu, 20 Apr 2023 14:31:39 +0200 From: Christoph Hellwig To: Breno Leitao Cc: Christoph Hellwig , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, asml.silence@gmail.com, axboe@kernel.dk, leit@fb.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, sagi@grimberg.me, kbusch@kernel.org, ming.lei@redhat.com Subject: Re: [PATCH 1/2] io_uring: Pass whole sqe to commands Message-ID: <20230420123139.GA32030@lst.de> References: <20230419102930.2979231-1-leitao@debian.org> <20230419102930.2979231-2-leitao@debian.org> <20230420045712.GA4239@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-20230420_053147_903703_B18E4C91 X-CRM114-Status: GOOD ( 15.88 ) 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 Thu, Apr 20, 2023 at 05:29:18AM -0700, Breno Leitao wrote: > > > - cmd_size = uring_cmd_pdu_size(req->ctx->flags & IORING_SETUP_SQE128); > > > + if (req->ctx->flags & IORING_SETUP_SQE128) > > > + size <<= 1; > > > > > > Why does this stop using uring_cmd_pdu_size()? > > Before, only the cmd payload (sqe->cmd) was being copied to the async > structure. We are copying over the whole sqe now, since we can use SQE > fields inside the ioctl callbacks (instead of only cmd fields). So, the > copy now is 64 bytes for single SQE or 128 for double SQEs. That's the point of this series and I get it. But why do we remove the nice and self-documenting helper that returns once or twice the sizeof of the SQE structure and instead add a magic open coded left shift?