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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD78FC38A02 for ; Sun, 30 Oct 2022 08:47:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7C5406B0078; Sun, 30 Oct 2022 04:47:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 774006B007B; Sun, 30 Oct 2022 04:47:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 663DB6B007D; Sun, 30 Oct 2022 04:47:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 538BB6B0078 for ; Sun, 30 Oct 2022 04:47:22 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3550A1205E5 for ; Sun, 30 Oct 2022 08:47:22 +0000 (UTC) X-FDA: 80076986724.29.5137B59 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf20.hostedemail.com (Postfix) with ESMTP id AF3121C0011 for ; Sun, 30 Oct 2022 08:47:21 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id DB72168AA6; Sun, 30 Oct 2022 09:47:18 +0100 (CET) Date: Sun, 30 Oct 2022 09:47:18 +0100 From: Christoph Hellwig To: Greg Kroah-Hartman Cc: Catalin Marinas , Linus Torvalds , Arnd Bergmann , Will Deacon , Marc Zyngier , Andrew Morton , Herbert Xu , Ard Biesheuvel , Christoph Hellwig , Isaac Manjarres , Saravana Kannan , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 2/2] treewide: Add the __GFP_PACKED flag to several non-DMA kmalloc() allocations Message-ID: <20221030084718.GC5278@lst.de> References: <20221025205247.3264568-1-catalin.marinas@arm.com> <20221025205247.3264568-3-catalin.marinas@arm.com> 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) ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none; spf=none (imf20.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667119641; a=rsa-sha256; cv=none; b=KFOLwyMXdrl7b4I/71pHIHSm3+5H0ds9m90d1tKHc6JxQXelLmuujW8cYJgxvxYUECZ+mG kRCT4cdpAum/SYn5sjuHz6wIQF2sOqI892qlfq8GZbZJt02kZn88oWyVh+EveRK0U4HcUZ yWGqKCB6rs7obDHfmVKTEUgAwd6oavE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667119641; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/d7i8q837qr59ysxtLsGR6L58G26LBMAACgvGiul+jY=; b=a3X79/Q2XGutElDLc2dVfX2jhdvCJTAAkW4i5TCDiYY/PO9ptsFPMntMubtZwES46Hzk80 zyALvRWdBKh9xKDbeZwcEC5a5q/qt2xM0ht5FgRmCVFW+K+3A6jri2kZd7KSxcwKtVoZGW KvvVd6XSA9ZjNmG+fRNM8wB6Z2Cm/KI= X-Rspam-User: Authentication-Results: imf20.hostedemail.com; dkim=none; spf=none (imf20.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-Rspamd-Server: rspam07 X-Stat-Signature: x6x9c3ki9eh586qbixkfb8p9g1xrqrfe X-Rspamd-Queue-Id: AF3121C0011 X-HE-Tag: 1667119641-40637 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 28, 2022 at 11:37:52AM +0200, Greg Kroah-Hartman wrote: > And here's actually the patch... How is this supposed to work? noderef means any dereference of it will now make sparse complain. And the whole point of the DMA is to get data into and out of the system, so except for corner cases like direct DMA to userspace (which won't use kmalloc) we absolutely do want to derference it to generate or consume the information.