On 24 August 2017 at 09:45, Joe Stringer <j...@ovn.org> wrote: > Recent changes[0] to make use of __compiletime_assert() from container_of() > increased the scope of this macro, resulting in a wider set of > situations where developers cannot compile their code using "-O0". I > noticed this when making use of the macro in my own development, and > spent more time than I'd like to admit tracking the problem down. This > patch documents the behavior in lieu of a compile-time assertion > implementation that does not rely on optimizations. > > Example compilation failure: > > ./include/linux/compiler.h:547:38: error: call to ‘__compiletime_assert_94’ > declared with attribute error: pointer type mismatch in container_of() > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > ./include/linux/compiler.h:530:4: note: in definition of macro > ‘__compiletime_assert’ > prefix ## suffix(); \ > ^~~~~~ > ./include/linux/compiler.h:547:2: note: in expansion of macro > ‘_compiletime_assert’ > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > ./include/linux/build_bug.h:46:37: note: in expansion of macro > ‘compiletime_assert’ > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > ./include/linux/kernel.h:860:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’ > BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ > ^~~~~~~~~~~~~~~~ > > [0] http://lkml.kernel.org/r/20170525120316.24473-7-abbo...@mev.co.uk > > Signed-off-by: Joe Stringer <j...@ovn.org>
This patch was written against the net-next tree, but is not targeted at the net-next tree. My usual submissions go there so my formatting scripts just inserted that. I can strip out and resend against a particular tree if this is a problem.
