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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 079F1C433DF for ; Thu, 15 Oct 2020 18:01:58 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E35E820797 for ; Thu, 15 Oct 2020 18:01:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="TsZiivOc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E35E820797 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hiffmcjydzTX8XVuezYrR/M3OSAfiLuadlvhcuEOQA0=; b=TsZiivOcB4rwce1IbxUJ1VG8H duLIb/nT2hMcyc1dcyDXLY1qYtCXiBtq9KPtlSXtSCWOOvkDqVM/gRDc0AMoHNOOIz2OyO6rvK+TZ Ylv5JBIkaYSLddPZRXQr167N0ZlIhpUILuk7PY/cPXol2zsRdJUopZhQizcEXnHvzMmb1hTui6ZOf uGjtzQXm7yijFRkzKT8zevmBfAoPfB+vmTzIZewleRVCAbTcYsK9bBA62rWrcXRg0jZ6JNgKFdAOY 79c9c1NJGkSpzEJsurZxGhgfEzZTYKOxzuUe+wabv1ROBOSYpUmc2qacfSyVkyqj2BFNKZM4I1H52 7QrnyXn4A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kT7ZZ-0002Uj-Up; Thu, 15 Oct 2020 18:01:53 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kT7ZX-0002UG-4Z for linux-nvme@lists.infradead.org; Thu, 15 Oct 2020 18:01:51 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 67BCE68B02; Thu, 15 Oct 2020 20:01:48 +0200 (CEST) Date: Thu, 15 Oct 2020 20:01:48 +0200 From: Christoph Hellwig To: Logan Gunthorpe Subject: Re: [PATCH] nvmet-passthru: Cleanup nvmet_passthru_map_sg() Message-ID: <20201015180148.GA23377@lst.de> References: <20201009231816.1524-1-logang@deltatee.com> <20201015075640.GJ14082@lst.de> MIME-Version: 1.0 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-20201015_140151_312422_C342C801 X-CRM114-Status: GOOD ( 13.35 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sagi Grimberg , Chaitanya Kulkarni , Christoph Hellwig , linux-nvme@lists.infradead.org, Douglas Gilbert Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Oct 15, 2020 at 10:01:30AM -0600, Logan Gunthorpe wrote: > > > On 2020-10-15 1:56 a.m., Christoph Hellwig wrote: > > On Fri, Oct 09, 2020 at 05:18:16PM -0600, Logan Gunthorpe wrote: > >> static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq) > >> { > >> - int sg_cnt = req->sg_cnt; > >> struct scatterlist *sg; > >> int op_flags = 0; > >> struct bio *bio; > >> int i, ret; > >> > >> + if (req->sg_cnt > BIO_MAX_PAGES) > >> + return -EINVAL; > > > > Don't you need to handle larger requests as well? Or at least > > limit MDTS? > > No and Yes: there is already code in nvmet_passthru_override_id_ctrl() > to limit MDTS based on max_segments and max_hw_sectors. But those are entirely unrelated to the bio size. BIO_MAX_PAGES is 256, so with 4k pages and assuming none can't be merged that is 1MB, while max_segments/max_hw_sectors could be something much larger. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme