From: Dan Carpenter Date: Tue, 11 Jun 2024 12:38:12 +0000 (+0300) Subject: bitops: Add a comment explaining the double underscore macros X-Git-Tag: v6.11-rc1~40^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e0eeb938adb0367de4b0946125a06142d8de7d37;p=thirdparty%2Fkernel%2Flinux.git bitops: Add a comment explaining the double underscore macros 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 Reviewed-by: Linus Walleij Signed-off-by: Yury Norov --- diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 46d4bdc634c0b..ba35bbf07798b 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -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)