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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 867B1C41514 for ; Fri, 2 Aug 2019 12:24:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67BC6216C8 for ; Fri, 2 Aug 2019 12:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390542AbfHBMYm (ORCPT ); Fri, 2 Aug 2019 08:24:42 -0400 Received: from ozlabs.org ([203.11.71.1]:45793 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729422AbfHBMYm (ORCPT ); Fri, 2 Aug 2019 08:24:42 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 460RDj5TGBz9sDB; Fri, 2 Aug 2019 22:24:37 +1000 (AEST) From: Michael Ellerman To: Bjorn Helgaas Cc: Nathan Chancellor , Tyrel Datwyler , Benjamin Herrenschmidt , Paul Mackerras , linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nick Desaulniers Subject: Re: [PATCH v2] PCI: rpaphp: Avoid a sometimes-uninitialized warning In-Reply-To: <20190802001102.GG151852@google.com> References: <20190603174323.48251-1-natechancellor@gmail.com> <20190603221157.58502-1-natechancellor@gmail.com> <20190722024313.GB55142@archlinux-threadripper> <87lfwq7lzb.fsf@concordia.ellerman.id.au> <20190802001102.GG151852@google.com> Date: Fri, 02 Aug 2019 22:24:36 +1000 Message-ID: <87v9vfkb5n.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bjorn Helgaas writes: > On Mon, Jul 22, 2019 at 02:05:12PM +1000, Michael Ellerman wrote: >> Nathan Chancellor writes: >> > On Mon, Jun 03, 2019 at 03:11:58PM -0700, Nathan Chancellor wrote: >> >> When building with -Wsometimes-uninitialized, clang warns: >> >> >> >> drivers/pci/hotplug/rpaphp_core.c:243:14: warning: variable 'fndit' is >> >> used uninitialized whenever 'for' loop exits because its condition is >> >> false [-Wsometimes-uninitialized] >> >> for (j = 0; j < entries; j++) { >> >> ^~~~~~~~~~~ >> >> drivers/pci/hotplug/rpaphp_core.c:256:6: note: uninitialized use occurs >> >> here >> >> if (fndit) >> >> ^~~~~ >> >> drivers/pci/hotplug/rpaphp_core.c:243:14: note: remove the condition if >> >> it is always true >> >> for (j = 0; j < entries; j++) { >> >> ^~~~~~~~~~~ >> >> drivers/pci/hotplug/rpaphp_core.c:233:14: note: initialize the variable >> >> 'fndit' to silence this warning >> >> int j, fndit; >> >> ^ >> >> = 0 >> >> >> >> fndit is only used to gate a sprintf call, which can be moved into the >> >> loop to simplify the code and eliminate the local variable, which will >> >> fix this warning. >> >> >> >> Link: https://github.com/ClangBuiltLinux/linux/issues/504 >> >> Fixes: 2fcf3ae508c2 ("hotplug/drc-info: Add code to search ibm,drc-info property") >> >> Suggested-by: Nick Desaulniers >> >> Signed-off-by: Nathan Chancellor >> >> --- >> >> >> >> v1 -> v2: >> >> >> >> * Eliminate fndit altogether by shuffling the sprintf call into the for >> >> loop and changing the if conditional, as suggested by Nick. >> >> >> >> drivers/pci/hotplug/rpaphp_core.c | 18 +++++++----------- >> >> 1 file changed, 7 insertions(+), 11 deletions(-) >> >> >> >> diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c >> >> index bcd5d357ca23..c3899ee1db99 100644 >> >> --- a/drivers/pci/hotplug/rpaphp_core.c >> >> +++ b/drivers/pci/hotplug/rpaphp_core.c >> >> @@ -230,7 +230,7 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name, >> >> struct of_drc_info drc; >> >> const __be32 *value; >> >> char cell_drc_name[MAX_DRC_NAME_LEN]; >> >> - int j, fndit; >> >> + int j; >> >> >> >> info = of_find_property(dn->parent, "ibm,drc-info", NULL); >> >> if (info == NULL) >> >> @@ -245,17 +245,13 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name, >> >> >> >> /* Should now know end of current entry */ >> >> >> >> - if (my_index > drc.last_drc_index) >> >> - continue; >> >> - >> >> - fndit = 1; >> >> - break; >> >> + /* Found it */ >> >> + if (my_index <= drc.last_drc_index) { >> >> + sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, >> >> + my_index); >> >> + break; >> >> + } >> >> } >> >> - /* Found it */ >> >> - >> >> - if (fndit) >> >> - sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, >> >> - my_index); >> >> >> >> if (((drc_name == NULL) || >> >> (drc_name && !strcmp(drc_name, cell_drc_name))) && >> >> -- >> >> 2.22.0.rc3 >> >> >> > >> > Hi all, >> > >> > Could someone please pick this up? >> >> I'll take it. >> >> I was expecting Bjorn to take it as a PCI patch, but I realise now that >> I merged that code in the first place so may as well take this too. >> >> I'll put it in my next branch once that opens next week. > > Sorry, I should have done something with this. Did you take it, > Michael? I don't see it in -next and haven't figured out where to > look in your git tree, so I can't tell. Just let me know either way > so I know whether to drop this or apply it. Yes I have it in my next-test, which will eventually become my next when I get time to rebase it, test and push etc: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/log/?h=next-test So no further action required on your part. cheers