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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 <mszeredi@redhat.com>
Fixes: 00a1a053eb ("ext4: atomically set inode->i_flags in ext4_set_inode_flags()")
Cc: Theodore Ts'o <tytso@mit.edu>
hifive-unleashed-5.1
Miklos Szeredi 2018-10-15 15:43:06 +02:00
parent e52a825048
commit 18127429a8
1 changed files with 7 additions and 7 deletions
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14
include/linux/bitops.h
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@ -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