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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 01207C433EF for ; Tue, 21 Sep 2021 09:36:22 +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 B64F861131 for ; Tue, 21 Sep 2021 09:36:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B64F861131 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=Wcw1qwbDtbbhOep42sO6BQIGGWM1OIb+NSS3MSEvI54=; b=B1I8xH2yfUwxAf S2UEEH5ymu71pS2cgThkrEh4QSUYcKt890pjAJW7/hpGReE1vXWDBLGIBBxaygcRNG9M+P6OudZm9 jGYCacCH+NzjC9V8/dxNpMR0no/kaTfrv37tEVkKrI6UclRd2KsegfILsf3h+nk38O5wdcnVBjZ8r CM3ggthD6ayXjb+16Iz1lI0VhrGcEE3PaQU1xxMYchogL8ELpgr3I7cgwGf11hUuDNpSBeKqfo3bE hUbDitpxWLEqvrjErEVzIJZGRSFrlolap4zbOTHE+YhVKnzMpCnjXR7H+9iY4RGBLNOxPHZc9wRfw /DHSXxuZYIZjb8w61o0A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mScAQ-0042uq-6C; Tue, 21 Sep 2021 09:34:22 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mScAN-0042u7-2E for linux-arm-kernel@lists.infradead.org; Tue, 21 Sep 2021 09:34:20 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9D68961131; Tue, 21 Sep 2021 09:34:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632216857; bh=26947zVG9riVqwftMN1dSoamNLEgoqIkp483H/vlQOo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Zo2HL5/V1BbcKSIpxSOBX/zdavkL4LAEANyknHxlliKWMePeJzZr4IeEC/oSTlAYq xMj+dgHL42dCKy96+2Wu4J+KlASIJoo7owJ5j3nG4mnqynPiESYhiWjdd49vSqqN++ 0ZCeYqjlhtTw3fLkQfHAh6iewWUS14jUeFvJupdrrV4Bo+FXTapZvJVk9VC5zxQRNv 7PaU2iomEyzPiSTKr8eQOOuM0OE9XwNEoX+ySL0No88y23eoUwj9XVk3/eIgpo48Gw X5e4Uks97yzbFv3Sdsz5bbAAFMJMKAv14aLh7zxHLMdaa1UylaD0EPl4w0+RE6gUvr oylJ1v4fD8l5w== Date: Tue, 21 Sep 2021 12:34:10 +0300 From: Mike Rapoport To: Christoph Hellwig Cc: Catalin Marinas , David Hildenbrand , Robin Murphy , Alex Bee , Will Deacon , Andrew Morton , Anshuman Khandual , Linux Kernel Mailing List , linux-mm@kvack.org, Linux ARM Subject: Re: [BUG 5.14] arm64/mm: dma memory mapping fails (in some cases) Message-ID: References: <0908ce39-7e30-91fa-68ef-11620f9596ae@arm.com> <60a11eba-2910-3b5f-ef96-97d4556c1596@redhat.com> <20210825102044.GA3420@arm.com> <20210918051843.GA16104@lst.de> <20210921082007.GA29121@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210921082007.GA29121@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210921_023419_168411_B2559758 X-CRM114-Status: GOOD ( 18.84 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 21, 2021 at 10:20:07AM +0200, Christoph Hellwig wrote: > On Mon, Sep 20, 2021 at 11:57:58AM +0100, Catalin Marinas wrote: > > > As this WARN_ON(pfn_valid()) is only present in dma_map_resource() it's > > > probably safe to drop it entirely. > > > > I agree, we should drop it. IIUC dma_map_resource() does not create any > > kernel mapping to cause problems with attribute aliasing. You'd need a > > prior devm_ioremap_resource() if you want access to that range from the > > CPU side. For arm64 at least, the latter ends up with a > > pfn_is_map_memory() check. > > It doesn't create any new mappings. The only real issue is that it > does the wrong thing for RAM in a way that might not be noticed on > simple (x86/PC) platforms. But if the mapping request was rejected by devm_ioremap_resource() because of an attempt to map RAM, why we would get to dma_map_resource() at all? -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel