bitops: define const_*() versions of the non-atomics

Define const_*() variants of the non-atomic bitops to be used when
the input arguments are compile-time constants, so that the compiler
will be always able to resolve those to compile-time constants as
well. Those are mostly direct aliases for generic_*() with one
exception for const_test_bit(): the original one is declared
atomic-safe and thus doesn't discard the `volatile` qualifier, so
in order to let optimize code, define it separately disregarding
the qualifier.
Add them to the compile-time type checks as well just in case.

Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 87087454a288..d393297287d5 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -37,6 +37,7 @@ extern unsigned long __sw_hweight64(__u64 w);
 /* Check that the bitops prototypes are sane */
 #define __check_bitop_pr(name)						\
 	static_assert(__same_type(arch_##name, generic_##name) &&	\
+		      __same_type(const_##name, generic_##name) &&	\
 		      __same_type(name, generic_##name))
 
 __check_bitop_pr(__set_bit);