On 03/23/2014 09:25 PM, Joe Perches wrote:
On Sun, 2014-03-23 at 21:14 -0700, Guenter Roeck wrote:
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.
Maybe it's better to use a statement expression to avoid
multiple calculations of t
Maybe;
#define KELVIN_TO_CELSIUS(t) \
({ \
long _t = (long)(t) - 2732; \
_t >= 0 ? (_t + 5) / 10 : (_t - 5) / 10; \
})
Possibly, but I only want to have a bug fixed which should possibly be applied
to -stable at some point. As such, I prefer the minimalistic approach.
Anything more fancy on top of that can be submitted as separate patch.
Guenter
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