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=-5.2 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 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 555F1C4338F for ; Fri, 23 Jul 2021 05:26:32 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E290060EB2 for ; Fri, 23 Jul 2021 05:26:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E290060EB2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=p9wS9XZENPT79xhJ1OLcd8TreWgET8CN5pcfHFaDnM4=; b=SNvFEf7dnvLPq+ +2xQvXVjsnHKEuok2xP5+QU9E+aLpRD3msGcOQqPCbCKh1pL4TgJ+gG53LvtKuIvOP0T2xFS02ZA1 E7CBzwEWI/kTan0Go8whOwOY3NJawcn5MZfuvTqPnApfYqBDV76UD6pp5c2TwiLTgAkBMoFaLP2JG WYeTRPcm++CMBl5PT1zIBuumkKs+6utCgxyfuaauEE4X3fScoyXhvGIJzwkE03dCIriAC+lAItSWs uHNbhl9Ksg960XheLXKsIGK/AEW39hjZBDN1JEhYlafwKFu6CAdYM/wEccZJqayU+yA0sFM8P3CLv rBAesdM1YBDqmvAMyeZQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6nhL-003R2J-PC; Fri, 23 Jul 2021 05:26:11 +0000 Received: from zeniv-ca.linux.org.uk ([142.44.231.140]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6nhI-003R1c-0W for linux-nvme@lists.infradead.org; Fri, 23 Jul 2021 05:26:09 +0000 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6ncc-0034np-I3; Fri, 23 Jul 2021 05:21:18 +0000 Date: Fri, 23 Jul 2021 05:21:18 +0000 From: Al Viro To: Christoph Hellwig Cc: Boris Pismenny , Boris Pismenny , dsahern@gmail.com, kuba@kernel.org, davem@davemloft.net, saeedm@nvidia.com, sagi@grimberg.me, axboe@fb.com, kbusch@kernel.org, edumazet@google.com, smalin@marvell.com, boris.pismenny@gmail.com, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, benishay@nvidia.com, ogerlitz@nvidia.com, yorayz@nvidia.com, Boris Pismenny , Ben Ben-Ishay , Or Gerlitz , Yoray Zack Subject: Re: [PATCH v5 net-next 02/36] iov_iter: DDP copy to iter/pages Message-ID: References: <20210722110325.371-1-borisp@nvidia.com> <20210722110325.371-3-borisp@nvidia.com> <6f7f96dc-f1e6-99d9-6ab4-920126615302@gmail.com> <20210723050302.GA30841@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210723050302.GA30841@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210722_222608_098037_37C3E8A1 X-CRM114-Status: GOOD ( 12.40 ) 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: , 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 Fri, Jul 23, 2021 at 07:03:02AM +0200, Christoph Hellwig wrote: > On Thu, Jul 22, 2021 at 11:23:38PM +0300, Boris Pismenny wrote: > > This routine, like other changes in this file, replicates the logic in > > memcpy_to_page. The only difference is that "ddp" avoids copies when the > > copy source and destinations buffers are one and the same. > > Now why can't we just make that change to the generic routine? Doable... replace memcpy(base, addr + off, len) with base != addr + off && memcpy(base, addr + off, len) in _copy_to_iter() and be done with that... _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme