On Thu, May 21, 2020 at 01:08:52PM +0200, Marco Elver wrote: > It appears that compilers have trouble with nested statements > expressions, as such make the data_race() macro be only a single > statement expression. This will help us avoid potential problems in > future as its usage increases. > > Link: https://lkml.kernel.org/r/[email protected] > Signed-off-by: Marco Elver <[email protected]> > --- > v2: > * Add patch to series in response to above linked discussion. > --- > include/linux/compiler.h | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index 7444f026eead..1f9bd9f35368 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -211,12 +211,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, > int val, > */ > #define data_race(expr) > \ > ({ \ > + __unqual_scalar_typeof(({ expr; })) __v; \ > __kcsan_disable_current(); \ > - ({ \ > - __unqual_scalar_typeof(({ expr; })) __v = ({ expr; }); \ > - __kcsan_enable_current(); \ > - __v; \ > - }); \ > + __v = ({ expr; }); \ > + __kcsan_enable_current(); \ > + __v; \
Hopefully it doesn't matter, but this will run into issues with 'const' non-scalar expressions. Will
