cpufreq: cpufreq-dt: avoid uninitialized variable warnings:

Message ID 1453736756-1959377-1-git-send-email-arnd@arndb.de
State New
Headers show

Commit Message

Arnd Bergmann Jan. 25, 2016, 3:45 p.m.
gcc warns quite a bit about values returned from allocate_resources()
in cpufreq-dt.c:

cpufreq-dt.c: In function 'cpufreq_init':
cpufreq-dt.c:327:6: error: 'cpu_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:197:17: note: 'cpu_dev' was declared here
cpufreq-dt.c:376:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:199:14: note: 'cpu_clk' was declared here
cpufreq-dt.c: In function 'dt_cpufreq_probe':
cpufreq-dt.c:461:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:447:14: note: 'cpu_clk' was declared here

The problem is that it's slightly hard for gcc to follow return
codes across PTR_ERR() calls.
This patch uses explicit assignments to the "ret" variable to make
it easier for gcc to verify that the code is actually correct,
without the need to add a bogus initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 drivers/cpufreq/cpufreq-dt.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

-- 
2.7.0

Comments

Rafael J. Wysocki Jan. 27, 2016, 10:56 p.m. | #1
On Monday, January 25, 2016 10:07:20 PM Viresh Kumar wrote:
> On 25-01-16, 16:45, Arnd Bergmann wrote:

> > gcc warns quite a bit about values returned from allocate_resources()

> > in cpufreq-dt.c:

> > 

> > cpufreq-dt.c: In function 'cpufreq_init':

> > cpufreq-dt.c:327:6: error: 'cpu_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]

> > cpufreq-dt.c:197:17: note: 'cpu_dev' was declared here

> > cpufreq-dt.c:376:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]

> > cpufreq-dt.c:199:14: note: 'cpu_clk' was declared here

> > cpufreq-dt.c: In function 'dt_cpufreq_probe':

> > cpufreq-dt.c:461:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]

> > cpufreq-dt.c:447:14: note: 'cpu_clk' was declared here

> > 

> > The problem is that it's slightly hard for gcc to follow return

> > codes across PTR_ERR() calls.

> > This patch uses explicit assignments to the "ret" variable to make

> > it easier for gcc to verify that the code is actually correct,

> > without the need to add a bogus initialization.

> > 

> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> > ---

> >  drivers/cpufreq/cpufreq-dt.c | 15 +++++++--------

> >  1 file changed, 7 insertions(+), 8 deletions(-)

> > 

> > diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c

> > index 9bc37c437874..0ca74d070058 100644

> > --- a/drivers/cpufreq/cpufreq-dt.c

> > +++ b/drivers/cpufreq/cpufreq-dt.c

> > @@ -142,15 +142,16 @@ static int allocate_resources(int cpu, struct device **cdev,

> >  

> >  try_again:

> >  	cpu_reg = regulator_get_optional(cpu_dev, reg);

> > -	if (IS_ERR(cpu_reg)) {

> > +	ret = PTR_ERR_OR_ZERO(cpu_reg);

> > +	if (ret) {

> >  		/*

> >  		 * If cpu's regulator supply node is present, but regulator is

> >  		 * not yet registered, we should try defering probe.

> >  		 */

> > -		if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {

> > +		if (ret == -EPROBE_DEFER) {

> >  			dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",

> >  				cpu);

> > -			return -EPROBE_DEFER;

> > +			return ret;

> >  		}

> >  

> >  		/* Try with "cpu-supply" */

> > @@ -159,18 +160,16 @@ try_again:

> >  			goto try_again;

> >  		}

> >  

> > -		dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",

> > -			cpu, PTR_ERR(cpu_reg));

> > +		dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);

> >  	}

> >  

> >  	cpu_clk = clk_get(cpu_dev, NULL);

> > -	if (IS_ERR(cpu_clk)) {

> > +	ret = PTR_ERR_OR_ZERO(cpu_clk);

> > +	if (ret) {

> >  		/* put regulator */

> >  		if (!IS_ERR(cpu_reg))

> >  			regulator_put(cpu_reg);

> >  

> > -		ret = PTR_ERR(cpu_clk);

> > -

> >  		/*

> >  		 * If cpu's clk node is present, but clock is not yet

> >  		 * registered, we should try defering probe.

> 

> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>


Applied, thanks!

Rafael

Patch

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index 9bc37c437874..0ca74d070058 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -142,15 +142,16 @@  static int allocate_resources(int cpu, struct device **cdev,
 
 try_again:
 	cpu_reg = regulator_get_optional(cpu_dev, reg);
-	if (IS_ERR(cpu_reg)) {
+	ret = PTR_ERR_OR_ZERO(cpu_reg);
+	if (ret) {
 		/*
 		 * If cpu's regulator supply node is present, but regulator is
 		 * not yet registered, we should try defering probe.
 		 */
-		if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
+		if (ret == -EPROBE_DEFER) {
 			dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
 				cpu);
-			return -EPROBE_DEFER;
+			return ret;
 		}
 
 		/* Try with "cpu-supply" */
@@ -159,18 +160,16 @@  try_again:
 			goto try_again;
 		}
 
-		dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
-			cpu, PTR_ERR(cpu_reg));
+		dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);
 	}
 
 	cpu_clk = clk_get(cpu_dev, NULL);
-	if (IS_ERR(cpu_clk)) {
+	ret = PTR_ERR_OR_ZERO(cpu_clk);
+	if (ret) {
 		/* put regulator */
 		if (!IS_ERR(cpu_reg))
 			regulator_put(cpu_reg);
 
-		ret = PTR_ERR(cpu_clk);
-
 		/*
 		 * If cpu's clk node is present, but clock is not yet
 		 * registered, we should try defering probe.