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Thu, 27 Jun 2019 12:18:39 -0700 (PDT) Date: Thu, 27 Jun 2019 12:18:37 -0700 From: Nathan Chancellor To: Tyrel Datwyler , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: Bjorn Helgaas , 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 Message-ID: <20190627191837.GA111331@archlinux-epyc> References: <20190603174323.48251-1-natechancellor@gmail.com> <20190603221157.58502-1-natechancellor@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190603221157.58502-1-natechancellor@gmail.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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 > Gentle ping, can someone pick this up? Cheers, Nathan