* [PATCH] PM / OPP: avoid maybe-uninitialized warning
@ 2016-09-15 15:38 Arnd Bergmann
2016-09-15 21:45 ` Stephen Boyd
2016-09-16 2:49 ` Viresh Kumar
0 siblings, 2 replies; 3+ messages in thread
From: Arnd Bergmann @ 2016-09-15 15:38 UTC (permalink / raw)
To: Viresh Kumar, Nishanth Menon, Stephen Boyd
Cc: Arnd Bergmann, Rafael J. Wysocki, linux-pm, linux-kernel
When CONFIG_OPTIMIZE_INLINING is set and we are building with -Wmaybe-uninitialized
enabled, we can get a warning for the opp core driver:
drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
drivers/base/power/opp/core.c:560:8: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
This has only now appeared as a result of commit 797da5598f3a ("PM / devfreq:
Add COMPILE_TEST for build coverage"), which makes the driver visible in
some configurations that didn't have it before.
The warning is a false positive that I got with gcc-6.1.1, but there is
a simple workaround in removing the local variables that we get warnings
for (all three are affected depending on the configuration). This also
makes the code easier to read.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/base/power/opp/core.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index df0c70963d9e..4c7c6da7a989 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -584,7 +584,6 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
struct clk *clk;
unsigned long freq, old_freq;
unsigned long u_volt, u_volt_min, u_volt_max;
- unsigned long ou_volt, ou_volt_min, ou_volt_max;
int ret;
if (unlikely(!target_freq)) {
@@ -620,11 +619,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
}
old_opp = _find_freq_ceil(opp_table, &old_freq);
- if (!IS_ERR(old_opp)) {
- ou_volt = old_opp->u_volt;
- ou_volt_min = old_opp->u_volt_min;
- ou_volt_max = old_opp->u_volt_max;
- } else {
+ if (IS_ERR(old_opp)) {
dev_err(dev, "%s: failed to find current OPP for freq %lu (%ld)\n",
__func__, old_freq, PTR_ERR(old_opp));
}
@@ -683,7 +678,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
restore_voltage:
/* This shouldn't harm even if the voltages weren't updated earlier */
if (!IS_ERR(old_opp))
- _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
+ _set_opp_voltage(dev, reg, old_opp->u_volt,
+ old_opp->u_volt_min, old_opp->u_volt_max);
return ret;
}
--
2.9.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] PM / OPP: avoid maybe-uninitialized warning
2016-09-15 15:38 [PATCH] PM / OPP: avoid maybe-uninitialized warning Arnd Bergmann
@ 2016-09-15 21:45 ` Stephen Boyd
2016-09-16 2:49 ` Viresh Kumar
1 sibling, 0 replies; 3+ messages in thread
From: Stephen Boyd @ 2016-09-15 21:45 UTC (permalink / raw)
To: Arnd Bergmann, Viresh Kumar, Nishanth Menon
Cc: Rafael J. Wysocki, linux-pm, linux-kernel
On 09/15/2016 08:38 AM, Arnd Bergmann wrote:
> When CONFIG_OPTIMIZE_INLINING is set and we are building with -Wmaybe-uninitialized
> enabled, we can get a warning for the opp core driver:
>
> drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
> drivers/base/power/opp/core.c:560:8: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> This has only now appeared as a result of commit 797da5598f3a ("PM / devfreq:
> Add COMPILE_TEST for build coverage"), which makes the driver visible in
> some configurations that didn't have it before.
>
> The warning is a false positive that I got with gcc-6.1.1, but there is
> a simple workaround in removing the local variables that we get warnings
> for (all three are affected depending on the configuration). This also
> makes the code easier to read.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] PM / OPP: avoid maybe-uninitialized warning
2016-09-15 15:38 [PATCH] PM / OPP: avoid maybe-uninitialized warning Arnd Bergmann
2016-09-15 21:45 ` Stephen Boyd
@ 2016-09-16 2:49 ` Viresh Kumar
1 sibling, 0 replies; 3+ messages in thread
From: Viresh Kumar @ 2016-09-16 2:49 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Viresh Kumar, Nishanth Menon, Stephen Boyd, Rafael J. Wysocki,
linux-pm, linux-kernel
On 15-09-16, 17:38, Arnd Bergmann wrote:
> When CONFIG_OPTIMIZE_INLINING is set and we are building with -Wmaybe-uninitialized
> enabled, we can get a warning for the opp core driver:
>
> drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
> drivers/base/power/opp/core.c:560:8: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> This has only now appeared as a result of commit 797da5598f3a ("PM / devfreq:
> Add COMPILE_TEST for build coverage"), which makes the driver visible in
> some configurations that didn't have it before.
>
> The warning is a false positive that I got with gcc-6.1.1, but there is
> a simple workaround in removing the local variables that we get warnings
> for (all three are affected depending on the configuration). This also
> makes the code easier to read.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/base/power/opp/core.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> index df0c70963d9e..4c7c6da7a989 100644
> --- a/drivers/base/power/opp/core.c
> +++ b/drivers/base/power/opp/core.c
> @@ -584,7 +584,6 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
> struct clk *clk;
> unsigned long freq, old_freq;
> unsigned long u_volt, u_volt_min, u_volt_max;
> - unsigned long ou_volt, ou_volt_min, ou_volt_max;
> int ret;
>
> if (unlikely(!target_freq)) {
> @@ -620,11 +619,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
> }
>
> old_opp = _find_freq_ceil(opp_table, &old_freq);
> - if (!IS_ERR(old_opp)) {
> - ou_volt = old_opp->u_volt;
> - ou_volt_min = old_opp->u_volt_min;
> - ou_volt_max = old_opp->u_volt_max;
> - } else {
> + if (IS_ERR(old_opp)) {
> dev_err(dev, "%s: failed to find current OPP for freq %lu (%ld)\n",
> __func__, old_freq, PTR_ERR(old_opp));
> }
> @@ -683,7 +678,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
> restore_voltage:
> /* This shouldn't harm even if the voltages weren't updated earlier */
> if (!IS_ERR(old_opp))
> - _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> + _set_opp_voltage(dev, reg, old_opp->u_volt,
> + old_opp->u_volt_min, old_opp->u_volt_max);
>
> return ret;
> }
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-09-15 15:38 [PATCH] PM / OPP: avoid maybe-uninitialized warning Arnd Bergmann
2016-09-15 21:45 ` Stephen Boyd
2016-09-16 2:49 ` Viresh Kumar
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