From: Nathan Chancellor <natechancellor@gmail.com>
To: Tyrel Datwyler <tyreld@linux.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-pci@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
Bjorn Helgaas <bhelgaas@google.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] PCI: rpaphp: Avoid a sometimes-uninitialized warning
Date: Thu, 27 Jun 2019 12:18:37 -0700 [thread overview]
Message-ID: <20190627191837.GA111331@archlinux-epyc> (raw)
In-Reply-To: <20190603221157.58502-1-natechancellor@gmail.com>
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 <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>
> 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
next prev parent reply other threads:[~2019-06-27 19:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-03 17:43 [PATCH] PCI: rpaphp: Avoid a sometimes-uninitialized warning Nathan Chancellor
2019-06-03 21:07 ` Nick Desaulniers
2019-06-03 21:51 ` Nathan Chancellor
2019-06-03 22:11 ` [PATCH v2] " Nathan Chancellor
2019-06-04 0:03 ` Tyrel Datwyler
2019-06-27 19:18 ` Nathan Chancellor [this message]
2019-06-28 2:57 ` Joel Savitz
2019-07-22 2:43 ` Nathan Chancellor
2019-07-22 4:05 ` Michael Ellerman
2019-08-02 0:11 ` Bjorn Helgaas
2019-08-02 12:24 ` Michael Ellerman
2019-08-10 10:20 ` Michael Ellerman
2019-06-04 6:24 ` [PATCH] " Christophe Leroy
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