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Date: Tue, 6 Oct 2015 09:45:29 -0700 From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com> To: linux-kernel@...r.kernel.org Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com, akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com, josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com, dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com, bobby.prani@...il.com, "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com> Subject: [PATCH tip/core/rcu 08/13] rcu_sync: Introduce rcu_sync_dtor() From: Oleg Nesterov <oleg@...hat.com> 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@...hat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org> Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com> --- include/linux/rcu_sync.h | 1 + kernel/rcu/sync.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) 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); + } +} -- 2.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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