On Fri, 15 May 2020 at 17:04, Marco Elver <[email protected]> wrote:
>
> The volatile access no longer needs to be wrapped in data_race(),
> because we require compilers that emit instrumentation distinguishing
> volatile accesses.
>
> Signed-off-by: Marco Elver <[email protected]>
> ---
> include/linux/compiler.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 17c98b215572..fce56402c082 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -229,7 +229,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f,
> int val,
> #define __READ_ONCE_SCALAR(x) \
> ({ \
> typeof(x) *__xp = &(x); \
> - __unqual_scalar_typeof(x) __x = data_race(__READ_ONCE(*__xp)); \
> + __unqual_scalar_typeof(x) __x = __READ_ONCE(*__xp); \
> kcsan_check_atomic_read(__xp, sizeof(*__xp)); \
Some self-review: We don't need kcsan_check_atomic anymore, and this
should be removed.
I'll send v2 to address this (together with fix to data_race()
removing nested statement expressions).
> smp_read_barrier_depends(); \
> (typeof(x))__x; \
> @@ -250,7 +250,7 @@ do {
> \
> do { \
> typeof(x) *__xp = &(x); \
> kcsan_check_atomic_write(__xp, sizeof(*__xp)); \
Same.
> - data_race(({ __WRITE_ONCE(*__xp, val); 0; })); \
> + __WRITE_ONCE(*__xp, val); \
> } while (0)
>
> #define WRITE_ONCE(x, val) \
> --
> 2.26.2.761.g0e0b3e54be-goog
>
