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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-07-14 18:35:23 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-08-04 08:49:21 -0700 |
| commit | 12d560f4ea87030667438a169912380be00cea4b (patch) | |
| tree | 3b60a7b97e849bd68573db48dd8608cb43f05694 /kernel/rcu | |
| parent | 3dbe43f6fba9f2a0e46e371733575a45704c22ab (diff) | |
| download | linux-12d560f4ea87030667438a169912380be00cea4b.tar.bz2 | |
rcu,locking: Privatize smp_mb__after_unlock_lock()
RCU is the only thing that uses smp_mb__after_unlock_lock(), and is
likely the only thing that ever will use it, so this commit makes this
macro private to RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 0412030ca882..2e991f8361e4 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -653,3 +653,15 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ } #endif /* #ifdef CONFIG_RCU_TRACE */ + +/* + * Place this after a lock-acquisition primitive to guarantee that + * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies + * if the UNLOCK and LOCK are executed by the same CPU or if the + * UNLOCK and LOCK operate on the same lock variable. + */ +#ifdef CONFIG_PPC +#define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */ +#else /* #ifdef CONFIG_PPC */ +#define smp_mb__after_unlock_lock() do { } while (0) +#endif /* #else #ifdef CONFIG_PPC */ |