diff options
author | Oleg Nesterov <oleg@redhat.com> | 2019-04-23 14:07:24 +0200 |
---|---|---|
committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-05-28 09:05:23 -0700 |
commit | 95bf33b55ff4465399bad843f1d8d618c8baf1f3 (patch) | |
tree | 9ddcd2a9ed6f70a50a4ff6d7bc0c767b6dc98ae0 | |
parent | a188339ca5a396acc588e5851ed7e19f66b0ebd9 (diff) |
rcu/sync: Kill rcu_sync_type/gp_type
Now that the RCU flavors have been consolidated, rcu_sync_type makes no
sense because none of internal update functions aside from .held() depend
on gp_type. This commit therefore removes this field and consolidates
the relevant code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[ paulmck: Added RCU and RCU-bh checks to rcu_sync_is_idle(). ]
[ paulmck: And applied subsequent feedback from Oleg Nesterov. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
-rw-r--r-- | include/linux/percpu-rwsem.h | 2 | ||||
-rw-r--r-- | include/linux/rcu_sync.h | 36 | ||||
-rw-r--r-- | kernel/locking/percpu-rwsem.c | 2 | ||||
-rw-r--r-- | kernel/rcu/sync.c | 55 |
4 files changed, 17 insertions, 78 deletions
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 03cb4b6f842e..6887636ea169 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -20,7 +20,7 @@ struct percpu_rw_semaphore { #define DEFINE_STATIC_PERCPU_RWSEM(name) \ static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \ static struct percpu_rw_semaphore name = { \ - .rss = __RCU_SYNC_INITIALIZER(name.rss, RCU_SCHED_SYNC), \ + .rss = __RCU_SYNC_INITIALIZER(name.rss), \ .read_count = &__percpu_rwsem_rc_##name, \ .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \ .writer = __RCUWAIT_INITIALIZER(name.writer), \ diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h index 6fc53a1345b3..87971e85519c 100644 --- a/include/linux/rcu_sync.h +++ b/include/linux/rcu_sync.h @@ -13,8 +13,6 @@ #include <linux/wait.h> #include <linux/rcupdate.h> -enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC }; - /* Structure to mediate between updaters and fastpath-using readers. */ struct rcu_sync { int gp_state; @@ -23,52 +21,38 @@ struct rcu_sync { int cb_state; struct rcu_head cb_head; - - enum rcu_sync_type gp_type; }; -extern void rcu_sync_lockdep_assert(struct rcu_sync *); - /** * rcu_sync_is_idle() - Are readers permitted to use their fastpaths? * @rsp: Pointer to rcu_sync structure to use for synchronization * - * Returns true if readers are permitted to use their fastpaths. - * Must be invoked within an RCU read-side critical section whose - * flavor matches that of the rcu_sync struture. + * Returns true if readers are permitted to use their fastpaths. Must be + * invoked within some flavor of RCU read-side critical section. */ static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) { -#ifdef CONFIG_PROVE_RCU - rcu_sync_lockdep_assert(rsp); -#endif + RCU_LOCKDEP_WARN(!rcu_read_lock_held() && + !rcu_read_lock_bh_held() && + !rcu_read_lock_sched_held(), + "suspicious rcu_sync_is_idle() usage"); return !rsp->gp_state; /* GP_IDLE */ } -extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); +extern void rcu_sync_init(struct rcu_sync *); extern void rcu_sync_enter_start(struct rcu_sync *); 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) { \ +#define __RCU_SYNC_INITIALIZER(name) { \ .gp_state = 0, \ .gp_count = 0, \ .gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ .cb_state = 0, \ - .gp_type = type, \ } -#define __DEFINE_RCU_SYNC(name, type) \ - struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) - -#define DEFINE_RCU_SYNC(name) \ - __DEFINE_RCU_SYNC(name, RCU_SYNC) - -#define DEFINE_RCU_SCHED_SYNC(name) \ - __DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) - -#define DEFINE_RCU_BH_SYNC(name) \ - __DEFINE_RCU_SYNC(name, RCU_BH_SYNC) +#define DEFINE_RCU_SYNC(name) \ + struct rcu_sync name = __RCU_SYNC_INITIALIZER(name) #endif /* _LINUX_RCU_SYNC_H_ */ diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index f17dad99eec8..48cab93a47fd 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -17,7 +17,7 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem, return -ENOMEM; /* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */ - rcu_sync_init(&sem->rss, RCU_SCHED_SYNC); + rcu_sync_init(&sem->rss); __init_rwsem(&sem->rw_sem, name, rwsem_key); rcuwait_init(&sem->writer); sem->readers_block = 0; diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c index a8304d90573f..ee427e138dad 100644 --- a/kernel/rcu/sync.c +++ b/kernel/rcu/sync.c @@ -10,65 +10,20 @@ #include <linux/rcu_sync.h> #include <linux/sched.h> -#ifdef CONFIG_PROVE_RCU -#define __INIT_HELD(func) .held = func, -#else -#define __INIT_HELD(func) -#endif - -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 -} gp_ops[] = { - [RCU_SYNC] = { - .sync = synchronize_rcu, - .call = call_rcu, - .wait = rcu_barrier, - __INIT_HELD(rcu_read_lock_held) - }, - [RCU_SCHED_SYNC] = { - .sync = synchronize_rcu, - .call = call_rcu, - .wait = rcu_barrier, - __INIT_HELD(rcu_read_lock_sched_held) - }, - [RCU_BH_SYNC] = { - .sync = synchronize_rcu, - .call = call_rcu, - .wait = rcu_barrier, - __INIT_HELD(rcu_read_lock_bh_held) - }, -}; - enum { GP_IDLE = 0, GP_PENDING, GP_PASSED }; enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY }; #define rss_lock gp_wait.lock -#ifdef CONFIG_PROVE_RCU -void rcu_sync_lockdep_assert(struct rcu_sync *rsp) -{ - RCU_LOCKDEP_WARN(!gp_ops[rsp->gp_type].held(), - "suspicious rcu_sync_is_idle() usage"); -} - -EXPORT_SYMBOL_GPL(rcu_sync_lockdep_assert); -#endif - /** * rcu_sync_init() - Initialize an rcu_sync structure * @rsp: Pointer to rcu_sync structure to be initialized * @type: Flavor of RCU with which to synchronize rcu_sync structure */ -void rcu_sync_init(struct rcu_sync *rsp, enum rcu_sync_type type) +void rcu_sync_init(struct rcu_sync *rsp) { memset(rsp, 0, sizeof(*rsp)); init_waitqueue_head(&rsp->gp_wait); - rsp->gp_type = type; } /** @@ -114,7 +69,7 @@ void rcu_sync_enter(struct rcu_sync *rsp) WARN_ON_ONCE(need_wait && need_sync); if (need_sync) { - gp_ops[rsp->gp_type].sync(); + synchronize_rcu(); rsp->gp_state = GP_PASSED; wake_up_all(&rsp->gp_wait); } else if (need_wait) { @@ -167,7 +122,7 @@ static void rcu_sync_func(struct rcu_head *rhp) * to catch a later GP. */ rsp->cb_state = CB_PENDING; - gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func); + call_rcu(&rsp->cb_head, rcu_sync_func); } else { /* * We're at least a GP after rcu_sync_exit(); eveybody will now @@ -195,7 +150,7 @@ void rcu_sync_exit(struct rcu_sync *rsp) if (!--rsp->gp_count) { if (rsp->cb_state == CB_IDLE) { rsp->cb_state = CB_PENDING; - gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func); + call_rcu(&rsp->cb_head, rcu_sync_func); } else if (rsp->cb_state == CB_PENDING) { rsp->cb_state = CB_REPLAY; } @@ -220,7 +175,7 @@ void rcu_sync_dtor(struct rcu_sync *rsp) spin_unlock_irq(&rsp->rss_lock); if (cb_state != CB_IDLE) { - gp_ops[rsp->gp_type].wait(); + rcu_barrier(); WARN_ON_ONCE(rsp->cb_state != CB_IDLE); } } |