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Fri, 2 Aug 2019 10:11:07 +1000 (AEST) Received: from localhost (unknown [69.71.4.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1394A2080C; Fri, 2 Aug 2019 00:11:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564704665; bh=eW7F5798CjDmOzeoFlM6FrvKP9mNOge+/pN3w8NdF/8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fnX7M40ahP6OU1THYNFdxmP2J5YyI4SVk3AQpe5PtsvXXn18Gmw958x0rV+4pPEtV fs6jOO7LDQLcefUurUJwAPeBNfSXyYB6ah7LpSChj9V61/Wro8RtZnKpCzRlSLK5/k Gp/hmC8xYGjZTfPbM4pIVM0NKyj75fHSlFrC29uM= Date: Thu, 1 Aug 2019 19:11:02 -0500 From: Bjorn Helgaas To: Michael Ellerman Subject: Re: [PATCH v2] PCI: rpaphp: Avoid a sometimes-uninitialized warning Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lfwq7lzb.fsf@concordia.ellerman.id.au> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tyrel Datwyler , linux-pci@vger.kernel.org, Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Paul Mackerras , Nathan Chancellor , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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. Bjorn