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Mikulas Patocka
8238b45798
There are several places in the kernel where wait_on_bit is not followed by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read). On architectures with weak memory ordering, it may happen that memory accesses that follow wait_on_bit are reordered before wait_on_bit and they may return invalid data. Fix this class of bugs by introducing a new function "test_bit_acquire" that works like test_bit, but has acquire memory ordering semantics. Signed-off-by: Mikulas Patocka <[email protected]> Acked-by: Will Deacon <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]>