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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 036B2C433E0 for ; Sat, 20 Feb 2021 03:39:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9BE264EE1 for ; Sat, 20 Feb 2021 03:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229903AbhBTDjS (ORCPT ); Fri, 19 Feb 2021 22:39:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229765AbhBTDjQ (ORCPT ); Fri, 19 Feb 2021 22:39:16 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6577CC061574; Fri, 19 Feb 2021 19:38:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=BVvSTy4Ph1YhvWKdzvOR3CYS1ZzHodAH4zck7F/I9So=; b=iOuAFPLXlVR9yXhHEn49dj0XHV 34VeudUAA30kub6pjTR/kgAfiVwLgagCpSxGgR+KlhRTUSVexeBMW9vEuEYZ41FFw0BsCfebZ0/CS TwnqgYlyUGbiXF2tcEL5VRe5BmmoMJnkYeQ/iBAVvj2Iug9g9GYRPDkw2sGUncVjHFqv4h0AnzxEx Rq6AUYa0+Oqeyk0qr8Vg5huuZ7u0WW4qACGFntkRXtRsNDW/QyhRVq4DTxThQ4Cr1myiWVwyb25HA jr96yA9BRwHIjkVj255aEi0j+QB7ZvVfCU+ppB8E+FFvIQvYe6Vd23S42bCRbskvayo3M+Z90Nwih EVofeSww==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lDJ4P-003aOy-38; Sat, 20 Feb 2021 03:36:48 +0000 Date: Sat, 20 Feb 2021 03:36:37 +0000 From: Matthew Wilcox To: SelvaKumar S Cc: linux-nvme@lists.infradead.org, kbusch@kernel.org, axboe@kernel.dk, damien.lemoal@wdc.com, hch@lst.de, sagi@grimberg.me, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com, snitzer@redhat.com, selvajove@gmail.com, joshiiitr@gmail.com, nj.shetty@samsung.com, joshi.k@samsung.com, javier.gonz@samsung.com, kch@kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH v5 3/4] nvme: add simple copy support Message-ID: <20210220033637.GA2858050@casper.infradead.org> References: <20210219124517.79359-1-selvakuma.s1@samsung.com> <20210219124517.79359-4-selvakuma.s1@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210219124517.79359-4-selvakuma.s1@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 19, 2021 at 06:15:16PM +0530, SelvaKumar S wrote: > + struct nvme_copy_range *range = NULL; [...] > + range = kmalloc_array(nr_range, sizeof(*range), > + GFP_ATOMIC | __GFP_NOWARN); [...] > + req->special_vec.bv_page = virt_to_page(range); > + req->special_vec.bv_offset = offset_in_page(range); > + req->special_vec.bv_len = sizeof(*range) * nr_range; [...] > +struct nvme_copy_range { > + __le64 rsvd0; > + __le64 slba; > + __le16 nlb; > + __le16 rsvd18; > + __le32 rsvd20; > + __le32 eilbrt; > + __le16 elbat; > + __le16 elbatm; > +}; so ... at 32 bytes, you can get 128 per 4kB page. What happens if you try to send down a command that attempts to copy 129 ranges?