Re: [PATCH 15/21] thermal: cooling: avoid uninitialied used gcc warning

Zhang Rui
2013-04-26T08:10:48Z

On Thu, 2013-04-25 at 19:28 +0200, Arnd Bergmann wrote:
> The newly rewritten get_property() function causes a bogus warning
> from gcc-3.8, which cannot figure out that "level" is always
> initialized at the point where it gets evaluated:
>
> drivers/thermal/cpu_cooling.c: In function 'get_property':
> drivers/thermal/cpu_cooling.c:189:37: warning: 'level' may be used uninitialized in this function [-Wmaybe-uninitialized]
> if (property == GET_FREQ && level == j) {
> ^
>
> Slightly rearranging the code makes this more obvious and
> avoids the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Amit Daniel kachhap <amit.daniel@samsung.com>

we already have a fix for this.
please refer to
https://patchwork.kernel.org/patch/2454891/

thanks for your patch, Arnd!

-rui
> ---
> drivers/thermal/cpu_cooling.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index 768b508..34878e6 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -165,10 +165,6 @@ static int get_property(unsigned int cpu, unsigned long input,
> return 0;
> }
>
> - if (property == GET_FREQ)
> - level = descend ? input : (max_level - input -1);
> -
> -
> for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
> /* ignore invalid entry */
> if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
> @@ -186,10 +182,15 @@ static int get_property(unsigned int cpu, unsigned long input,
> *output = descend ? j : (max_level - j - 1);
> return 0;
> }
> - if (property == GET_FREQ && level == j) {
> - /* get frequency by level */
> - *output = freq;
> - return 0;
> +
> + if (property == GET_FREQ) {
> + level = descend ? input : (max_level - input -1);
> +
> + if (level == j) {
> + /* get frequency by level */
> + *output = freq;
> + return 0;
> + }
> }
> j++;
> }