Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752493AbdIVSMt (ORCPT ); Fri, 22 Sep 2017 14:12:49 -0400 Received: from mail-wr0-f194.google.com ([209.85.128.194]:36003 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752270AbdIVSMr (ORCPT ); Fri, 22 Sep 2017 14:12:47 -0400 X-Google-Smtp-Source: AOwi7QAxMsn7Rg5JaAgBw83dPWdmVps4sBnZcSbwZyoIVygjD6YG6WRbwel2J+MS6GZNrs0Vsnh1e/hjahQ+wasqTQM= MIME-Version: 1.0 In-Reply-To: <20170922155605.GB15970@bhelgaas-glaptop.roam.corp.google.com> References: <1505132955-9517-1-git-send-email-geert@linux-m68k.org> <20170922155605.GB15970@bhelgaas-glaptop.roam.corp.google.com> From: Geert Uytterhoeven Date: Fri, 22 Sep 2017 20:12:46 +0200 X-Google-Sender-Auth: TFRGtEftq00GAzqCIaLgJbZRdXM Message-ID: Subject: Re: [PATCH] pci: Add dummy for pci_acs_enabled() if CONFIG_PCI=n to fix iommmu build To: Bjorn Helgaas Cc: Bjorn Helgaas , Arnd Bergmann , Alex Williamson , Joerg Roedel , linux-pci , iommu@lists.linux-foundation.org, "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8MICqbW029582 Content-Length: 1952 Lines: 49 Hi Björn, On Fri, Sep 22, 2017 at 5:56 PM, Bjorn Helgaas wrote: > On Mon, Sep 11, 2017 at 02:29:15PM +0200, Geert Uytterhoeven wrote: >> If CONFIG_PCI=n, and gcc (e.g. 4.1.2) decides not to inline >> get_pci_function_alias_group(), the build fails with: >> >> drivers/iommu/iommu.o: In function `get_pci_function_alias_group': >> iommu.c:(.text+0xfdc): undefined reference to `pci_acs_enabled' >> >> Due to the various dummies for PCI calls in the CONFIG_PCI=n case, >> pci_acs_enabled() isn't actually ever called, but not all versions of >> gcc are smart enough to realize that. >> >> While explicitly marking get_pci_function_alias_group() inline would fix >> the build, this would inflate the code for the CONFIG_PCI=y case, as >> get_pci_function_alias_group() is a not-so-small function called from >> two places. >> >> Hence fix the issue by introducing a dummy for pci_acs_enabled() >> instead. >> >> Signed-off-by: Geert Uytterhoeven > > Acked-by: Bjorn Helgaas > > Joerg, if you pick this up, would you mind capitalizing the subject > line to match the PCI convention, e.g., > > PCI: Add dummy pci_acs_enabled() for CONFIG_PCI=n build > > If it's too late for you to pick this up this week, I can include it > next week. I assume this is not related to a specific change, i.e., > it's not a regression? Should it be marked for stable? It was introduced by commit 0ae349a0f33fb040 ("iommu/qcom: Add qcom_iommu"), which enabled IOMMU support for compile-testing in e.g. allmodconfig on platforms that don't have IOMMUs. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds