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 97653EB64DD for ; Fri, 11 Aug 2023 08:36:30 +0000 (UTC) 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=e8sk6FhFlW4ZzSsN/0NZqHZX+y5GWmjt1D6D5x9QLtU=; b=DqWJOoyO1LNSpy y4ZV5Nftf96TDMDfZTrVpl8QxooEWS/O6AZubgnefXQYISS3Xtc3MsbO4ylCIUd4ShVJaAqsNpRFj TsOHceHUGDmxQdBJuSvF97ke4huu8jZ9NmLRm9p52p3cHZSkorfFSwAw62mGSNxR/7OeTMk80yMZr l6BAfeXvemxbV9MZtS1c1eatlJCxohxKwQAsGtaqCmg8mJyQXUcP8hKhw0+nNGKwrlTX2fDh0wLcR 6lOxV4T61uQQp8IkU6Co/6GRdpQeuDddOFnUdyMJAjmdh3mHKU+dpKJE21OTuKgMk53syOYKurCD7 vhc2Ox3aL4bT+g0tVXXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qUNdC-009rkP-1k; Fri, 11 Aug 2023 08:36:26 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qUNd8-009rjw-26; Fri, 11 Aug 2023 08:36:22 +0000 Date: Fri, 11 Aug 2023 01:36:22 -0700 From: Christoph Hellwig To: Richard Weinberger Cc: Christoph Hellwig , linux-mtd , Stephan Wurm , stable , Miquel Raynal , Vignesh Raghavendra , Oliver Neukum , Ali Akcaagac , Jamie Lenehan , James Bottomley , "Martin K. Petersen" , Ezequiel Garcia , linux-kernel , linux-scsi Subject: Re: [PATCH 1/7] ubi: block: Refactor sg list processing for highmem Message-ID: References: <20230810160019.16977-1-richard@nod.at> <20230810160019.16977-2-richard@nod.at> <298860961.5257332.1691684136772.JavaMail.zimbra@nod.at> <164102534.5258032.1691697286622.JavaMail.zimbra@nod.at> <156807159.5281174.1691742892935.JavaMail.zimbra@nod.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <156807159.5281174.1691742892935.JavaMail.zimbra@nod.at> X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Fri, Aug 11, 2023 at 10:34:52AM +0200, Richard Weinberger wrote: > ----- Urspr=FCngliche Mail ----- > > Von: "Christoph Hellwig" > > On Thu, Aug 10, 2023 at 09:54:46PM +0200, Richard Weinberger wrote: > >> > But why add the bounce buffering first if you can avoid it from the > >> > very beginning by just using kmap_local instead of adding a new > >> > caller for the deprecate kmap_atomic? > >> = > >> Because I want this fix also in all stable trees. kmap_local() is rath= er > >> new. When back porting patch 1/7, bounce buffers and kmap_atomic() > >> are needed anyway. > >> By doing this in patch 1/7 I avoid backport troubles and keep the > >> delta between upstream and stable trees minimal. > > = > > Just use plain kmap for the historic backports. > = > Hm, yes. For UBIblock kmap should be too expensive. ? kmap is a no-op for !highmem. And it will always be way cheaper than bounce buffering for the case where you are actually fed highmem pages. ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/