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>
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@ -236,17 +236,17 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
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#ifdef __KERNEL__
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#ifndef set_mask_bits
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#define set_mask_bits(ptr, _mask, _bits) \
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#define set_mask_bits(ptr, mask, bits) \
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({ \
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const typeof(*ptr) mask = (_mask), bits = (_bits); \
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typeof(*ptr) old, new; \
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const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
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typeof(*(ptr)) old__, new__; \
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\
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do { \
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old = READ_ONCE(*ptr); \
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new = (old & ~mask) | bits; \
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} while (cmpxchg(ptr, old, new) != old); \
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old__ = READ_ONCE(*(ptr)); \
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new__ = (old__ & ~mask__) | bits__; \
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} while (cmpxchg(ptr, old__, new__) != old__); \
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\
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new; \
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new__; \
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})
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#endif
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