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Subjectcheckpatch.pl: Wrong check SINGLE_STATEMENT_DO_WHILE_MACRO
Date
Hi,

I think your check for SINGLE_STATEMENT_DO_WHILE_MACRO is wrong. Just to give
an example:

#define foobar(x) \
do { \
if (pizza_ready(x)) \
eat_pizza(x); \
} while (0)


if (hungry(y))
foobar(x);
else
barfoo(x);

checkpatch does now complain about something like "WARNING: Single statement
macros should not use a do {} while (0) loop"

But we would have an ambiguous else when the do-while is removed. The code
works as expected with the do-while but the else is "attached" to the wrong
"if" when the do-while is removed.

And yes, this example is made that easy to make it easy to understand. There
are examples were static inline code would not work very well (vararg for
example).

Please fix or remove your check. Otherwise some people will be start to
overeagerly change these macros and break the kernel doing that.
--
Franz Schrober


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