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Commit edfa8728 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

bitops: protect variables in bit_clear_unless() macro 



Unprotected naming of local variables within bit_clear_unless() can easily
lead to using the wrong scope.

Noticed this by code review after having hit this issue in set_mask_bits()

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Fixes: 85ad1d13 ("md: set MD_CHANGE_PENDING in a atomic region")
Cc: Guoqing Jiang <gqjiang@suse.com>
parent 18127429

include/linux/bitops.h

+8 −8
Original line number Diff line number Diff line
@@ -251,18 +251,18 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, 
#endif



#ifndef bit_clear_unless

#define bit_clear_unless(ptr, _clear, _test)	\

#define bit_clear_unless(ptr, clear, test)	\

({								\

	const typeof(*ptr) clear = (_clear), test = (_test);	\

	typeof(*ptr) old, new;					\

	const typeof(*(ptr)) clear__ = (clear), test__ = (test);\

	typeof(*(ptr)) old__, new__;				\

								\

	do {							\

		old = READ_ONCE(*ptr);			\

		new = old & ~clear;				\

	} while (!(old & test) &&				\

		 cmpxchg(ptr, old, new) != old);		\

		old__ = READ_ONCE(*(ptr));			\

		new__ = old__ & ~clear__;			\

	} while (!(old__ & test__) &&				\

		 cmpxchg(ptr, old__, new__) != old__);		\

								\

	!(old & test);						\

	!(old__ & test__);					\

})

#endif