diff options
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/cpu.h | 2 | ||||
-rw-r--r-- | include/linux/list.h | 5 | ||||
-rw-r--r-- | include/linux/list_bl.h | 5 | ||||
-rw-r--r-- | include/linux/list_nulls.h | 3 | ||||
-rw-r--r-- | include/linux/percpu-rwsem.h | 3 | ||||
-rw-r--r-- | include/linux/rcu_sync.h | 86 | ||||
-rw-r--r-- | include/linux/rculist.h | 5 | ||||
-rw-r--r-- | include/linux/rcupdate.h | 59 | ||||
-rw-r--r-- | include/linux/rcutiny.h | 3 | ||||
-rw-r--r-- | include/linux/rcutree.h | 2 | ||||
-rw-r--r-- | include/linux/sched.h | 10 | ||||
-rw-r--r-- | include/linux/srcu.h | 5 |
12 files changed, 141 insertions, 47 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 23c30bdcca86..d2ca8c38f9c4 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -228,7 +228,6 @@ extern struct bus_type cpu_subsys; extern void cpu_hotplug_begin(void); extern void cpu_hotplug_done(void); extern void get_online_cpus(void); -extern bool try_get_online_cpus(void); extern void put_online_cpus(void); extern void cpu_hotplug_disable(void); extern void cpu_hotplug_enable(void); @@ -246,7 +245,6 @@ int cpu_down(unsigned int cpu); static inline void cpu_hotplug_begin(void) {} static inline void cpu_hotplug_done(void) {} #define get_online_cpus() do { } while (0) -#define try_get_online_cpus() true #define put_online_cpus() do { } while (0) #define cpu_hotplug_disable() do { } while (0) #define cpu_hotplug_enable() do { } while (0) diff --git a/include/linux/list.h b/include/linux/list.h index 3e3e64a61002..993395a2e55c 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -87,7 +87,7 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head) static inline void __list_del(struct list_head * prev, struct list_head * next) { next->prev = prev; - prev->next = next; + WRITE_ONCE(prev->next, next); } /** @@ -615,7 +615,8 @@ static inline void __hlist_del(struct hlist_node *n) { struct hlist_node *next = n->next; struct hlist_node **pprev = n->pprev; - *pprev = next; + + WRITE_ONCE(*pprev, next); if (next) next->pprev = pprev; } diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 2eb88556c5c5..8132214e8efd 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -93,9 +93,10 @@ static inline void __hlist_bl_del(struct hlist_bl_node *n) LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK); /* pprev may be `first`, so be careful not to lose the lock bit */ - *pprev = (struct hlist_bl_node *) + WRITE_ONCE(*pprev, + (struct hlist_bl_node *) ((unsigned long)next | - ((unsigned long)*pprev & LIST_BL_LOCKMASK)); + ((unsigned long)*pprev & LIST_BL_LOCKMASK))); if (next) next->pprev = pprev; } diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h index f266661d2666..444d2b1313bd 100644 --- a/include/linux/list_nulls.h +++ b/include/linux/list_nulls.h @@ -76,7 +76,8 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n) { struct hlist_nulls_node *next = n->next; struct hlist_nulls_node **pprev = n->pprev; - *pprev = next; + + WRITE_ONCE(*pprev, next); if (!is_a_nulls(next)) next->pprev = pprev; } diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 834c4e52cb2d..c2fa3ecb0dce 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -5,11 +5,12 @@ #include <linux/rwsem.h> #include <linux/percpu.h> #include <linux/wait.h> +#include <linux/rcu_sync.h> #include <linux/lockdep.h> struct percpu_rw_semaphore { + struct rcu_sync rss; unsigned int __percpu *fast_read_ctr; - atomic_t write_ctr; struct rw_semaphore rw_sem; atomic_t slow_read_ctr; wait_queue_head_t write_waitq; diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h new file mode 100644 index 000000000000..a63a33e6196e --- /dev/null +++ b/include/linux/rcu_sync.h @@ -0,0 +1,86 @@ +/* + * RCU-based infrastructure for lightweight reader-writer locking + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, you can access it online at + * http://www.gnu.org/licenses/gpl-2.0.html. + * + * Copyright (c) 2015, Red Hat, Inc. + * + * Author: Oleg Nesterov <oleg@redhat.com> + */ + +#ifndef _LINUX_RCU_SYNC_H_ +#define _LINUX_RCU_SYNC_H_ + +#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; + int gp_count; + wait_queue_head_t gp_wait; + + 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. + */ +static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) +{ +#ifdef CONFIG_PROVE_RCU + rcu_sync_lockdep_assert(rsp); +#endif + return !rsp->gp_state; /* GP_IDLE */ +} + +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, \ + .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) + +#endif /* _LINUX_RCU_SYNC_H_ */ diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 17c6b1f84a77..5ed540986019 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -247,10 +247,7 @@ static inline void list_splice_init_rcu(struct list_head *list, * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). */ #define list_entry_rcu(ptr, type, member) \ -({ \ - typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \ - container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \ -}) + container_of(lockless_dereference(ptr), type, member) /** * Where are list_empty_rcu() and list_first_entry_rcu()? diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 581abf848566..a0189ba67fde 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -160,7 +160,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename, * more than one CPU). */ void call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *head)); + rcu_callback_t func); #else /* #ifdef CONFIG_PREEMPT_RCU */ @@ -191,7 +191,7 @@ void call_rcu(struct rcu_head *head, * memory ordering guarantees. */ void call_rcu_bh(struct rcu_head *head, - void (*func)(struct rcu_head *head)); + rcu_callback_t func); /** * call_rcu_sched() - Queue an RCU for invocation after sched grace period. @@ -213,7 +213,7 @@ void call_rcu_bh(struct rcu_head *head, * memory ordering guarantees. */ void call_rcu_sched(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)); + rcu_callback_t func); void synchronize_sched(void); @@ -274,7 +274,7 @@ do { \ * See the description of call_rcu() for more detailed information on * memory ordering guarantees. */ -void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head)); +void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func); void synchronize_rcu_tasks(void); void rcu_barrier_tasks(void); @@ -297,12 +297,14 @@ void synchronize_rcu(void); static inline void __rcu_read_lock(void) { - preempt_disable(); + if (IS_ENABLED(CONFIG_PREEMPT_COUNT)) + preempt_disable(); } static inline void __rcu_read_unlock(void) { - preempt_enable(); + if (IS_ENABLED(CONFIG_PREEMPT_COUNT)) + preempt_enable(); } static inline void synchronize_rcu(void) @@ -535,29 +537,9 @@ static inline int rcu_read_lock_sched_held(void) #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ -/* Deprecate rcu_lockdep_assert(): Use RCU_LOCKDEP_WARN() instead. */ -static inline void __attribute((deprecated)) deprecate_rcu_lockdep_assert(void) -{ -} - #ifdef CONFIG_PROVE_RCU /** - * rcu_lockdep_assert - emit lockdep splat if specified condition not met - * @c: condition to check - * @s: informative message - */ -#define rcu_lockdep_assert(c, s) \ - do { \ - static bool __section(.data.unlikely) __warned; \ - deprecate_rcu_lockdep_assert(); \ - if (debug_lockdep_rcu_enabled() && !__warned && !(c)) { \ - __warned = true; \ - lockdep_rcu_suspicious(__FILE__, __LINE__, s); \ - } \ - } while (0) - -/** * RCU_LOCKDEP_WARN - emit lockdep splat if specified condition is met * @c: condition to check * @s: informative message @@ -594,7 +576,6 @@ static inline void rcu_preempt_sleep_check(void) #else /* #ifdef CONFIG_PROVE_RCU */ -#define rcu_lockdep_assert(c, s) deprecate_rcu_lockdep_assert() #define RCU_LOCKDEP_WARN(c, s) do { } while (0) #define rcu_sleep_check() do { } while (0) @@ -811,6 +792,28 @@ static inline void rcu_preempt_sleep_check(void) #define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0) /** + * rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism + * @p: The pointer to hand off + * + * This is simply an identity function, but it documents where a pointer + * is handed off from RCU to some other synchronization mechanism, for + * example, reference counting or locking. In C11, it would map to + * kill_dependency(). It could be used as follows: + * + * rcu_read_lock(); + * p = rcu_dereference(gp); + * long_lived = is_long_lived(p); + * if (long_lived) { + * if (!atomic_inc_not_zero(p->refcnt)) + * long_lived = false; + * else + * p = rcu_pointer_handoff(p); + * } + * rcu_read_unlock(); + */ +#define rcu_pointer_handoff(p) (p) + +/** * rcu_read_lock() - mark the beginning of an RCU read-side critical section * * When synchronize_rcu() is invoked on one CPU while other CPUs @@ -1065,7 +1068,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) #define __kfree_rcu(head, offset) \ do { \ BUILD_BUG_ON(!__is_kfree_rcu_offset(offset)); \ - kfree_call_rcu(head, (void (*)(struct rcu_head *))(unsigned long)(offset)); \ + kfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \ } while (0) /** diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index ff968b7af3a4..4c1aaf9cce7b 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -83,7 +83,7 @@ static inline void synchronize_sched_expedited(void) } static inline void kfree_call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)) + rcu_callback_t func) { call_rcu(head, func); } @@ -216,6 +216,7 @@ static inline bool rcu_is_watching(void) static inline void rcu_all_qs(void) { + barrier(); /* Avoid RCU read-side critical sections leaking across. */ } #endif /* __LINUX_RCUTINY_H */ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 5abec82f325e..60d15a080d7c 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -48,7 +48,7 @@ void synchronize_rcu_bh(void); void synchronize_sched_expedited(void); void synchronize_rcu_expedited(void); -void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); +void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func); /** * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period diff --git a/include/linux/sched.h b/include/linux/sched.h index b7b9501b41af..aec904bc3da9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1342,10 +1342,12 @@ struct sched_dl_entity { union rcu_special { struct { - bool blocked; - bool need_qs; - } b; - short s; + u8 blocked; + u8 need_qs; + u8 exp_need_qs; + u8 pad; /* Otherwise the compiler can store garbage here. */ + } b; /* Bits. */ + u32 s; /* Set of bits. */ }; struct rcu_node; diff --git a/include/linux/srcu.h b/include/linux/srcu.h index bdeb4567b71e..f5f80c5643ac 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -215,8 +215,11 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp) */ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp) { - int retval = __srcu_read_lock(sp); + int retval; + preempt_disable(); + retval = __srcu_read_lock(sp); + preempt_enable(); rcu_lock_acquire(&(sp)->dep_map); return retval; } |