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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5509DC433EF for ; Tue, 7 Dec 2021 11:15:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234901AbhLGLTD (ORCPT ); Tue, 7 Dec 2021 06:19:03 -0500 Received: from verein.lst.de ([213.95.11.211]:55809 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235629AbhLGLTB (ORCPT ); Tue, 7 Dec 2021 06:19:01 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id D841E68B05; Tue, 7 Dec 2021 12:15:26 +0100 (CET) Date: Tue, 7 Dec 2021 12:15:26 +0100 From: Christoph Hellwig To: Matthew Wilcox Cc: Christoph Hellwig , Amit Daniel Kachhap , linux-kernel@vger.kernel.org, Vincenzo Frascino , Kevin Brodsky , linux-fsdevel , kexec , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Young , Baoquan He , Vivek Goyal , x86 Subject: Re: [RFC PATCH 01/14] fs/proc/vmcore: Update read_from_oldmem() for user pointer Message-ID: <20211207111526.GA18554@lst.de> References: <20211203104231.17597-1-amit.kachhap@arm.com> <20211203104231.17597-2-amit.kachhap@arm.com> <20211206140451.GA4936@lst.de> <20211206145422.GA8794@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) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 06, 2021 at 03:07:15PM +0000, Matthew Wilcox wrote: > > > What do you think to adding a generic copy_pfn_to_iter()? Not sure > > > which APIs to use to implement it ... some architectures have weird > > > requirements about which APIs can be used for what kinds of PFNs. > > > > Hmm. I though kmap_local_pfn(_prot) is all we need? > > In the !HIGHMEM case, that calls pfn_to_page(), and I think the > point of this path is that we don't have a struct page for this pfn. Indeed. But to me this suggest that the !highmem stub is broken and we should probably fix it rather than adding yet another interface. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1muYRc-008Epc-DM for kexec@lists.infradead.org; Tue, 07 Dec 2021 11:15:37 +0000 Date: Tue, 7 Dec 2021 12:15:26 +0100 From: Christoph Hellwig Subject: Re: [RFC PATCH 01/14] fs/proc/vmcore: Update read_from_oldmem() for user pointer Message-ID: <20211207111526.GA18554@lst.de> References: <20211203104231.17597-1-amit.kachhap@arm.com> <20211203104231.17597-2-amit.kachhap@arm.com> <20211206140451.GA4936@lst.de> <20211206145422.GA8794@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Matthew Wilcox Cc: Christoph Hellwig , Amit Daniel Kachhap , linux-kernel@vger.kernel.org, Vincenzo Frascino , Kevin Brodsky , linux-fsdevel , kexec , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Young , Baoquan He , Vivek Goyal , x86 On Mon, Dec 06, 2021 at 03:07:15PM +0000, Matthew Wilcox wrote: > > > What do you think to adding a generic copy_pfn_to_iter()? Not sure > > > which APIs to use to implement it ... some architectures have weird > > > requirements about which APIs can be used for what kinds of PFNs. > > > > Hmm. I though kmap_local_pfn(_prot) is all we need? > > In the !HIGHMEM case, that calls pfn_to_page(), and I think the > point of this path is that we don't have a struct page for this pfn. Indeed. But to me this suggest that the !highmem stub is broken and we should probably fix it rather than adding yet another interface. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec