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1 Prior Operation Subsequent Operation2 --------------- ---------------------------3 C Self R W RMW Self R W DR DW RMW SV4 -- ---- - - --- ---- - - -- -- --- --5 6Relaxed store Y Y7Relaxed load Y Y Y Y8Relaxed RMW operation Y Y Y Y9rcu_dereference() Y Y Y Y10Successful *_acquire() R Y Y Y Y Y Y11Successful *_release() C Y Y Y W Y12smp_rmb() Y R Y Y R13smp_wmb() Y W Y Y W14smp_mb() & synchronize_rcu() CP Y Y Y Y Y Y Y Y15Successful full non-void RMW CP Y Y Y Y Y Y Y Y Y Y Y16smp_mb__before_atomic() CP Y Y Y a a a a Y17smp_mb__after_atomic() CP a a Y Y Y Y Y Y18 19 20Key: Relaxed: A relaxed operation is either READ_ONCE(), WRITE_ONCE(),21 a *_relaxed() RMW operation, an unsuccessful RMW22 operation, a non-value-returning RMW operation such23 as atomic_inc(), or one of the atomic*_read() and24 atomic*_set() family of operations.25 C: Ordering is cumulative26 P: Ordering propagates27 R: Read, for example, READ_ONCE(), or read portion of RMW28 W: Write, for example, WRITE_ONCE(), or write portion of RMW29 Y: Provides ordering30 a: Provides ordering given intervening RMW atomic operation31 DR: Dependent read (address dependency)32 DW: Dependent write (address, data, or control dependency)33 RMW: Atomic read-modify-write operation34 SELF: Orders self, as opposed to accesses before and/or after35 SV: Orders later accesses to the same variable36