Add the new rcu_sync_ops->wait() method and the new helper,
rcu_sync_dtor().
It is needed if you are going to, say, kfree(rcu_sync_object).
It simply calls ops->wait() to "flush" the potentially pending
rcu callback.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
include/linux/rcusync.h | 2 ++
kernel/rcusync.c | 21 +++++++++++++++++++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/include/linux/rcusync.h b/include/linux/rcusync.h
index ab787c1..33864a0 100644
--- a/include/linux/rcusync.h
+++ b/include/linux/rcusync.h
@@ -7,6 +7,7 @@
struct rcu_sync_ops {
void (*sync)(void);
void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
+ void (*wait)(void);
#ifdef CONFIG_PROVE_RCU
int (*held)(void);
#endif
@@ -36,6 +37,7 @@ enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
extern void rcu_sync_init(struct rcu_sync_struct *, enum rcu_sync_type);
extern void rcu_sync_enter(struct rcu_sync_struct *);
extern void rcu_sync_exit(struct rcu_sync_struct *);
+extern void rcu_sync_dtor(struct rcu_sync_struct *);
extern struct rcu_sync_ops rcu_sync_ops_array[];
diff --git a/kernel/rcusync.c b/kernel/rcusync.c
index 21cde9b..bb311eb 100644
--- a/kernel/rcusync.c
+++ b/kernel/rcusync.c
@@ -16,16 +16,19 @@ struct rcu_sync_ops rcu_sync_ops_array[] = {
[RCU_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
+ .wait = rcu_barrier,
__INIT_HELD(rcu_read_lock_held)
},
[RCU_SCHED_SYNC] = {
.sync = synchronize_sched,
.call = call_rcu_sched,
+ .wait = rcu_barrier_sched,
__INIT_HELD(rcu_read_lock_sched_held)
},
[RCU_BH_SYNC] = {
.sync = synchronize_rcu_bh,
.call = call_rcu_bh,
+ .wait = rcu_barrier_bh,
__INIT_HELD(rcu_read_lock_bh_held)
},
};
@@ -113,3 +116,21 @@ void rcu_sync_exit(struct rcu_sync_struct *rss)
}
spin_unlock_irq(&rss->rss_lock);
}
+
+void rcu_sync_dtor(struct rcu_sync_struct *rss)
+{
+ int cb_state;
+
+ BUG_ON(rss->gp_count);
+
+ spin_lock_irq(&rss->rss_lock);
+ if (rss->cb_state == CB_REPLAY)
+ rss->cb_state = CB_PENDING;
+ cb_state = rss->cb_state;
+ spin_unlock_irq(&rss->rss_lock);
+
+ if (cb_state != CB_IDLE) {
+ rss->ops->wait();
+ BUG_ON(rss->cb_state != CB_IDLE);
+ }
+}
--
1.5.5.1
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