diff options
| -rw-r--r-- | include/linux/rcupdate.h | 12 | ||||
| -rw-r--r-- | kernel/rcu/srcu.c | 10 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 12 |
3 files changed, 20 insertions, 14 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 01f71e1d2e94..6ade6a52d9d4 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -1161,5 +1161,17 @@ do { \ ftrace_dump(oops_dump_mode); \ } while (0) +/* + * Place this after a lock-acquisition primitive to guarantee that + * an UNLOCK+LOCK pair acts 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 */ + #endif /* __LINUX_RCUPDATE_H */ diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index c9a0015e1c2e..665bc9951523 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -358,6 +358,7 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *head, head->next = NULL; head->func = func; spin_lock_irqsave(&sp->queue_lock, flags); + smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */ rcu_batch_queue(&sp->batch_queue, head); if (!sp->running) { sp->running = true; @@ -391,6 +392,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) head->next = NULL; head->func = wakeme_after_rcu; spin_lock_irq(&sp->queue_lock); + smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */ if (!sp->running) { /* steal the processing owner */ sp->running = true; @@ -410,8 +412,11 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) spin_unlock_irq(&sp->queue_lock); } - if (!done) + if (!done) { wait_for_completion(&rcu.completion); + smp_mb(); /* Caller's later accesses after GP. */ + } + } /** @@ -579,7 +584,8 @@ static void srcu_advance_batches(struct srcu_struct *sp, int trycount) /* * Invoke a limited number of SRCU callbacks that have passed through * their grace period. If there are more to do, SRCU will reschedule - * the workqueue. + * the workqueue. Note that needed memory barriers have been executed + * in this task's context by srcu_readers_active_idx_check(). */ static void srcu_invoke_callbacks(struct srcu_struct *sp) { diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index fe98dd24adf8..abcc25bdcb29 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -688,18 +688,6 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) #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 */ - -/* * Wrappers for the rcu_node::lock acquire and release. * * Because the rcu_nodes form a tree, the tree traversal locking will observe |