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bitops: Add a comment explaining the double underscore macros

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Linus Walleij pointed out that a new comer might be confused about the
difference between set_bit() and __set_bit().  Add a comment explaining
the difference.

Link: https://lore.kernel.org/all/CACRpkdZFPG_YLici-BmYfk9HZ36f4WavCN3JNotkk8cPgCODCg@mail.gmail.com/
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
This commit is contained in:
Dan Carpenter 2024-06-11 15:38:12 +03:00 committed by Yury Norov
parent e334771d83
commit e0eeb938ad
1 changed files with 5 additions and 0 deletions
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include/linux/bitops.h
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@ -47,12 +47,17 @@ extern unsigned long __sw_hweight64(__u64 w);
__builtin_constant_p(*(const unsigned long *)(addr))) ? \
const##op(nr, addr) : op(nr, addr))
/*
* The following macros are non-atomic versions of their non-underscored
* counterparts.
*/
#define __set_bit(nr, addr) bitop(___set_bit, nr, addr)
#define __clear_bit(nr, addr) bitop(___clear_bit, nr, addr)
#define __change_bit(nr, addr) bitop(___change_bit, nr, addr)
#define __test_and_set_bit(nr, addr) bitop(___test_and_set_bit, nr, addr)
#define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr)
#define __test_and_change_bit(nr, addr) bitop(___test_and_change_bit, nr, addr)
#define test_bit(nr, addr) bitop(_test_bit, nr, addr)
#define test_bit_acquire(nr, addr) bitop(_test_bit_acquire, nr, addr)