From: Miklos Szeredi Date: Mon, 15 Oct 2018 13:43:06 +0000 (+0200) Subject: bitops: protect variables in set_mask_bits() macro X-Git-Tag: v4.20-rc1~45^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=18127429a854e7607b859484880b8e26cee9ddab;p=thirdparty%2Fkernel%2Flinux.git bitops: protect variables in set_mask_bits() macro Unprotected naming of local variables within the set_mask_bits() can easily lead to using the wrong scope. Noticed this when "set_mask_bits(&foo->bar, 0, mask)" behaved as no-op. Signed-off-by: Miklos Szeredi Fixes: 00a1a053ebe5 ("ext4: atomically set inode->i_flags in ext4_set_inode_flags()") Cc: Theodore Ts'o --- diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 7ddb1349394db..d18ee0e63c322 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -236,17 +236,17 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, #ifdef __KERNEL__ #ifndef set_mask_bits -#define set_mask_bits(ptr, _mask, _bits) \ +#define set_mask_bits(ptr, mask, bits) \ ({ \ - const typeof(*ptr) mask = (_mask), bits = (_bits); \ - typeof(*ptr) old, new; \ + const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \ + typeof(*(ptr)) old__, new__; \ \ do { \ - old = READ_ONCE(*ptr); \ - new = (old & ~mask) | bits; \ - } while (cmpxchg(ptr, old, new) != old); \ + old__ = READ_ONCE(*(ptr)); \ + new__ = (old__ & ~mask__) | bits__; \ + } while (cmpxchg(ptr, old__, new__) != old__); \ \ - new; \ + new__; \ }) #endif