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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 089AFC43387 for ; Sun, 16 Dec 2018 09:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB496217FA for ; Sun, 16 Dec 2018 09:02:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730008AbeLPJCo (ORCPT ); Sun, 16 Dec 2018 04:02:44 -0500 Received: from verein.lst.de ([213.95.11.211]:56419 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729758AbeLPJCo (ORCPT ); Sun, 16 Dec 2018 04:02:44 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id 20CD068D93; Sun, 16 Dec 2018 10:02:42 +0100 (CET) Date: Sun, 16 Dec 2018 10:02:42 +0100 From: Christoph Hellwig To: Guenter Roeck Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, Linus Torvalds , Jesper Dangaard Brouer , Tariq Toukan , Ilias Apalodimas , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Robin Murphy , Konrad Rzeszutek Wilk , Tony Luck , Fenghua Yu , Marek Szyprowski , Keith Busch , Jonathan Derrick , linux-pci@vger.kernel.org, linux-ia64@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [15/15] dma-mapping: bypass indirect calls for dma-direct Message-ID: <20181216090242.GA30702@lst.de> References: <20181207190720.18517-16-hch@lst.de> <20181215174654.GA25694@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181215174654.GA25694@roeck-us.net> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 15, 2018 at 09:46:54AM -0800, Guenter Roeck wrote: > Hi, > > On Fri, Dec 07, 2018 at 11:07:20AM -0800, Christoph Hellwig wrote: > > Avoid expensive indirect calls in the fast path DMA mapping > > operations by directly calling the dma_direct_* ops if we are using > > the directly mapped DMA operations. > > > > This patch results in arm64 boot failures. Reverting the patch fixes > the problem. Bisect results are attached. Per logs, the system fails > to instantiate the root device. Examples from two logs: This patch should fix it, it has already been sent out Friday and I'm just waiting for an ACK from the arm64 maintainers before applying it: -- >From e6dc770875bc551ff77fe5673f5dd3c8ac242536 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 14 Dec 2018 15:18:08 +0100 Subject: arm64: default to the direct mapping in get_arch_dma_ops Otherwise the direct mapping won't work at all given that a NULL dev->dma_ops causes a fallback. Note that we already explicitly set dev->dma_ops to dma_dummy_ops for dma-incapable devices, so this fallback should not be needed anyway. Fixes: 356da6d0cd ("dma-mapping: bypass indirect calls for dma-direct") Signed-off-by: Christoph Hellwig Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski --- arch/arm64/include/asm/dma-mapping.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h index 273e778f7de2..95dbf3ef735a 100644 --- a/arch/arm64/include/asm/dma-mapping.h +++ b/arch/arm64/include/asm/dma-mapping.h @@ -26,11 +26,7 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) { - /* - * We expect no ISA devices, and all other DMA masters are expected to - * have someone call arch_setup_dma_ops at device creation time. - */ - return &dma_dummy_ops; + return NULL; } void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, -- 2.19.2