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| author | Oleg Nesterov <oleg@redhat.com> | 2015-08-21 20:42:52 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-10-06 21:25:21 +0300 |
| commit | 07899a6e5f56136028c44a57ad0451e797365ac3 (patch) | |
| tree | 48fc600387bae30a64284ae0d7acfb767277cfde | |
| parent | 3a518b76af7bb411efe6dd090fbf098e29accb2e (diff) | |
| download | linux-07899a6e5f56136028c44a57ad0451e797365ac3.tar.xz | |
rcu_sync: Introduce rcu_sync_dtor()
This commit allows rcu_sync structures to be safely deallocated,
The trick is to add a new ->wait field to the gp_ops array.
This field is a pointer to the rcu_barrier() function corresponding
to the flavor of RCU in question. This allows a new rcu_sync_dtor()
to wait for any outstanding callbacks before freeing the rcu_sync
structure.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| -rw-r--r-- | include/linux/rcu_sync.h | 1 | ||||
| -rw-r--r-- | kernel/rcu/sync.c | 26 |
2 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h index 1f2d4fc30b04..8069d6468bc4 100644 --- a/include/linux/rcu_sync.h +++ b/include/linux/rcu_sync.h @@ -62,6 +62,7 @@ static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); extern void rcu_sync_enter(struct rcu_sync *); extern void rcu_sync_exit(struct rcu_sync *); +extern void rcu_sync_dtor(struct rcu_sync *); #define __RCU_SYNC_INITIALIZER(name, type) { \ .gp_state = 0, \ diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c index 01c9807a7f73..1e353f0a2b66 100644 --- a/kernel/rcu/sync.c +++ b/kernel/rcu/sync.c @@ -32,6 +32,7 @@ static const struct { void (*sync)(void); void (*call)(struct rcu_head *, void (*)(struct rcu_head *)); + void (*wait)(void); #ifdef CONFIG_PROVE_RCU int (*held)(void); #endif @@ -39,16 +40,19 @@ static const struct { [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) }, }; @@ -195,3 +199,25 @@ void rcu_sync_exit(struct rcu_sync *rsp) } spin_unlock_irq(&rsp->rss_lock); } + +/** + * rcu_sync_dtor() - Clean up an rcu_sync structure + * @rsp: Pointer to rcu_sync structure to be cleaned up + */ +void rcu_sync_dtor(struct rcu_sync *rsp) +{ + int cb_state; + + BUG_ON(rsp->gp_count); + + spin_lock_irq(&rsp->rss_lock); + if (rsp->cb_state == CB_REPLAY) + rsp->cb_state = CB_PENDING; + cb_state = rsp->cb_state; + spin_unlock_irq(&rsp->rss_lock); + + if (cb_state != CB_IDLE) { + gp_ops[rsp->gp_type].wait(); + BUG_ON(rsp->cb_state != CB_IDLE); + } +} |