diff options
Diffstat (limited to 'kernel/include/linux/rcu_sync.h')
| -rw-r--r-- | kernel/include/linux/rcu_sync.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/kernel/include/linux/rcu_sync.h b/kernel/include/linux/rcu_sync.h new file mode 100644 index 000000000..a63a33e61 --- /dev/null +++ b/kernel/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_ */ |