Messages in this thread Patch in this message | | | From | Guenter Roeck <> | Subject | [PATCH] thermal: Fix KELVIN_TO_CELSIUS macro | Date | Sun, 23 Mar 2014 21:14:56 -0700 |
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It is always a good idea to use paranthesis around macro parameters to avoid undesired side effects.
In this specific case, KELVIN_TO_CELSIUS() is used in drivers/platform/x86/asus-wmi.c with parameter "value & 0xFFFF", which due to operator evaluation order causes more or less random results.
Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- include/linux/thermal.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/thermal.h b/include/linux/thermal.h index f7e11c7..02488c9 100644 --- a/include/linux/thermal.h +++ b/include/linux/thermal.h @@ -41,8 +41,8 @@ #define THERMAL_NO_LIMIT THERMAL_CSTATE_INVALID /* Unit conversion macros */ -#define KELVIN_TO_CELSIUS(t) (long)(((long)t-2732 >= 0) ? \ - ((long)t-2732+5)/10 : ((long)t-2732-5)/10) +#define KELVIN_TO_CELSIUS(t) (long)(((long)(t)-2732 >= 0) ? \ + ((long)(t)-2732+5)/10 : ((long)(t)-2732-5)/10) #define CELSIUS_TO_KELVIN(t) ((t)*10+2732) /* Adding event notification support elements */ -- 1.7.9.7
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