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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2017-11-14 12:57:01 +0100 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2017-11-16 09:02:24 +0100 |
commit | 97a98f6cd767b3a68279890488c7b451788f84f4 (patch) | |
tree | 279ba49b9f03b0f111ff5df771e9d4f3b3fd4feb /rtemsbsd/include/machine | |
parent | LOCKING(9): Remove dead code (DDB) (diff) | |
download | rtems-libbsd-97a98f6cd767b3a68279890488c7b451788f84f4.tar.bz2 |
RWLOCK(9): Add reader/writer lock implementation
Diffstat (limited to 'rtemsbsd/include/machine')
-rw-r--r-- | rtemsbsd/include/machine/rtems-bsd-rwlock.h | 60 | ||||
-rw-r--r-- | rtemsbsd/include/machine/rtems-bsd-rwlockimpl.h | 429 |
2 files changed, 489 insertions, 0 deletions
diff --git a/rtemsbsd/include/machine/rtems-bsd-rwlock.h b/rtemsbsd/include/machine/rtems-bsd-rwlock.h new file mode 100644 index 00000000..51b41604 --- /dev/null +++ b/rtemsbsd/include/machine/rtems-bsd-rwlock.h @@ -0,0 +1,60 @@ +/** + * @file + * + * @ingroup rtems_bsd_machine + * + * @brief TODO. + */ + +/* + * Copyright (c) 2017 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Dornierstr. 4 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCK_H_ +#define _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCK_H_ + +#include <rtems/score/threadq.h> + +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +typedef struct { + Thread_queue_Control writer_queue; + Thread_queue_Control reader_queue; + int readers; + int nest_level; +} rtems_bsd_rwlock; + +#ifdef __cplusplus +} +#endif /* __cplusplus */ + +#endif /* _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCK_H_ */ diff --git a/rtemsbsd/include/machine/rtems-bsd-rwlockimpl.h b/rtemsbsd/include/machine/rtems-bsd-rwlockimpl.h new file mode 100644 index 00000000..663e7000 --- /dev/null +++ b/rtemsbsd/include/machine/rtems-bsd-rwlockimpl.h @@ -0,0 +1,429 @@ +/** + * @file + * + * @ingroup rtems_bsd_machine + * + * @brief Implementation of a reader/writer lock with priority inheritance for + * exclusive owners (writer). + */ + +/* + * Copyright (c) 2017 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Dornierstr. 4 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCKIMPL_H_ +#define _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCKIMPL_H_ + +#include <machine/rtems-bsd-rwlock.h> +#include <machine/rtems-bsd-support.h> + +#include <sys/types.h> +#include <sys/lock.h> + +#include <rtems/score/threadimpl.h> + +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +typedef struct { + Thread_queue_Context writer; + Thread_queue_Context reader; +} rtems_bsd_rwlock_context; + +static inline void +rtems_bsd_rwlock_context_init(rtems_bsd_rwlock_context *context) +{ + + _Thread_queue_Context_initialize(&context->writer); +} + +static inline void +rtems_bsd_rwlock_init(struct lock_object *lock, rtems_bsd_rwlock *rw, + struct lock_class *class, const char *name, const char *type, int flags) +{ + _Thread_queue_Initialize(&rw->writer_queue, name); + _Thread_queue_Initialize(&rw->reader_queue, name); + rw->readers = 0; + rw->nest_level = 0; + lock_init(lock, class, name, type, flags); +} + +void rtems_bsd_rwlock_wlock_more(const struct lock_object *lock, + rtems_bsd_rwlock *rw, Thread_Control *executing, + rtems_bsd_rwlock_context *context); + +void rtems_bsd_rwlock_wunlock_more(rtems_bsd_rwlock *rw, + Thread_Control *wowner, rtems_bsd_rwlock_context *context); + +void rtems_bsd_rwlock_rlock_more(rtems_bsd_rwlock *rw, + rtems_bsd_rwlock_context *context); + +void rtems_bsd_rwlock_runlock_more(rtems_bsd_rwlock *rw, + rtems_bsd_rwlock_context *context); + +void rtems_bsd_rwlock_ready_waiting_readers(rtems_bsd_rwlock *rw, + rtems_bsd_rwlock_context *context); + +#define rtems_bsd_rwlock_isr_disable(isr_level, context) \ +do { \ + _ISR_Local_disable(isr_level); \ + _ISR_lock_ISR_disable_profile( \ + &(context)->writer.Lock_context.Lock_context) \ +} while (0) + +static inline void +rtems_bsd_rwlock_acquire_critical(rtems_bsd_rwlock *rw, + rtems_bsd_rwlock_context *context) +{ + + _Thread_queue_Queue_acquire_critical(&rw->writer_queue.Queue, + &rw->writer_queue.Lock_stats, + &context->writer.Lock_context.Lock_context); +#if defined(RTEMS_SMP) && defined(RTEMS_DEBUG) + rw->writer_queue.owner = _SMP_lock_Who_am_I(); +#endif +} + +static inline void +rtems_bsd_rwlock_release(rtems_bsd_rwlock *rw, ISR_Level isr_level, + rtems_bsd_rwlock_context *context) +{ + +#if defined(RTEMS_SMP) && defined(RTEMS_DEBUG) + _Assert( _Thread_queue_Is_lock_owner( &rw->writer_queue ) ); + rw->writer_queue.owner = SMP_LOCK_NO_OWNER; +#endif + _Thread_queue_Queue_release_critical(&rw->writer_queue.Queue, + &context->writer.Lock_context.Lock_context); + _ISR_Local_enable(isr_level); +} + +static inline void +rtems_bsd_rwlock_set_isr_level(rtems_bsd_rwlock_context *context, + ISR_Level isr_level) +{ + + _ISR_lock_Context_set_level(&context->writer.Lock_context.Lock_context, + isr_level); +} + +static inline Thread_Control * +rtems_bsd_rwlock_wowner(const rtems_bsd_rwlock *rw) +{ + + return (rw->writer_queue.Queue.owner); +} + +static inline void +rtems_bsd_rwlock_set_wowner(rtems_bsd_rwlock *rw, Thread_Control *wowner) +{ + + rw->writer_queue.Queue.owner = wowner; +} + +static inline void +rtems_bsd_rwlock_wlock(struct lock_object *lock, rtems_bsd_rwlock *rw) +{ + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + Thread_Control *executing; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + executing = _Thread_Executing; + rtems_bsd_rwlock_acquire_critical(rw, &context); + + if (__predict_true(rtems_bsd_rwlock_wowner(rw) == NULL && + rw->readers == 0)) { + rtems_bsd_rwlock_set_wowner(rw, executing); + _Thread_Resource_count_increment(executing); + rtems_bsd_rwlock_release(rw, isr_level, &context); + } else { + rtems_bsd_rwlock_set_isr_level(&context, isr_level); + rtems_bsd_rwlock_wlock_more(lock, rw, executing, + &context); + } +} + +static inline int +rtems_bsd_rwlock_try_wlock(struct lock_object *lock, rtems_bsd_rwlock *rw) +{ + int success; + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + Thread_Control *executing; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + executing = _Thread_Executing; + rtems_bsd_rwlock_acquire_critical(rw, &context); + + if (rw->readers == 0) { + Thread_Control *wowner; + + wowner = rtems_bsd_rwlock_wowner(rw); + + if (wowner == NULL) { + rtems_bsd_rwlock_set_wowner(rw, executing); + _Thread_Resource_count_increment(executing); + success = 1; + } else if (wowner == executing) { + BSD_ASSERT(lock->lo_flags & LO_RECURSABLE); + ++rw->nest_level; + success = 1; + } else { + success = 0; + } + } else { + success = 0; + } + + rtems_bsd_rwlock_release(rw, isr_level, &context); + + return (success); +} + +static inline void +rtems_bsd_rwlock_wunlock(rtems_bsd_rwlock *rw) +{ + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + Thread_Control *wowner; + int nest_level; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + rtems_bsd_rwlock_acquire_critical(rw, &context); + + nest_level = rw->nest_level; + wowner = rtems_bsd_rwlock_wowner(rw); + + BSD_ASSERT(wowner == _Thread_Executing); + + if (__predict_true(nest_level == 0)) { + rtems_bsd_rwlock_set_wowner(rw, NULL); + _Thread_Resource_count_decrement(wowner); + + if (__predict_true( + _Thread_queue_Is_empty(&rw->writer_queue.Queue) && + _Thread_queue_Is_empty(&rw->reader_queue.Queue))) { + rtems_bsd_rwlock_release(rw, isr_level, &context); + } else { + rtems_bsd_rwlock_set_isr_level(&context, + isr_level); + rtems_bsd_rwlock_wunlock_more(rw, wowner, + &context); + } + } else { + rw->nest_level = nest_level - 1; + rtems_bsd_rwlock_release(rw, isr_level, &context); + } +} + +static inline int +rtems_bsd_rwlock_wowned(const rtems_bsd_rwlock *rw) +{ + + return (rtems_bsd_rwlock_wowner(rw) == _Thread_Get_executing()); +} + +static inline int +rtems_bsd_rwlock_recursed(const rtems_bsd_rwlock *rw) +{ + + return (rw->nest_level != 0); +} + +static inline void +rtems_bsd_rwlock_rlock(struct lock_object *lock, rtems_bsd_rwlock *rw) +{ + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + rtems_bsd_rwlock_acquire_critical(rw, &context); + + if (__predict_true(rtems_bsd_rwlock_wowner(rw) == NULL && + _Thread_queue_Is_empty(&rw->writer_queue.Queue))) { + ++rw->readers; + _Thread_Resource_count_increment(_Thread_Executing); + rtems_bsd_rwlock_release(rw, isr_level, &context); + } else { + rtems_bsd_rwlock_set_isr_level(&context, isr_level); + rtems_bsd_rwlock_rlock_more(rw, &context); + } +} + +static inline int +rtems_bsd_rwlock_try_rlock(struct lock_object *lock, rtems_bsd_rwlock *rw) +{ + int success; + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + rtems_bsd_rwlock_acquire_critical(rw, &context); + + if (__predict_true(rtems_bsd_rwlock_wowner(rw) == NULL && + _Thread_queue_Is_empty(&rw->writer_queue.Queue))) { + ++rw->readers; + _Thread_Resource_count_increment(_Thread_Executing); + success = 1; + } else { + success = 0; + } + + rtems_bsd_rwlock_release(rw, isr_level, &context); + + return (success); +} + +static inline void +rtems_bsd_rwlock_runlock(rtems_bsd_rwlock *rw) +{ + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + int readers; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + rtems_bsd_rwlock_acquire_critical(rw, &context); + + readers = rw->readers; + _Thread_Resource_count_decrement(_Thread_Executing); + + if (__predict_true(readers == 1)) { + rw->readers = 0; + + if (__predict_true( + _Thread_queue_Is_empty(&rw->writer_queue.Queue) && + _Thread_queue_Is_empty(&rw->reader_queue.Queue))) { + rtems_bsd_rwlock_release(rw, isr_level, + &context); + } else { + rtems_bsd_rwlock_set_isr_level(&context, + isr_level); + rtems_bsd_rwlock_runlock_more(rw, &context); + } + } else { + rw->readers = readers - 1; + rtems_bsd_rwlock_release(rw, isr_level, &context); + } +} + +static inline int +rtems_bsd_rwlock_try_upgrade(rtems_bsd_rwlock *rw) +{ + int success; + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + Thread_Control *executing; + Thread_Control *wowner; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + executing = _Thread_Executing; + rtems_bsd_rwlock_acquire_critical(rw, &context); + + wowner = rtems_bsd_rwlock_wowner(rw); + BSD_ASSERT(wowner == NULL); + + if (rw->readers == 1) { + rw->readers = 0; + rtems_bsd_rwlock_set_wowner(rw, executing); + /* FIXME: priority inheritance */ + success = 1; + } else { + success = 0; + } + + rtems_bsd_rwlock_release(rw, isr_level, &context); + + return (success); +} + +static inline void +rtems_bsd_rwlock_downgrade(rtems_bsd_rwlock *rw) +{ + ISR_Level isr_level; + rtems_bsd_rwlock_context context; + Thread_Control *wowner; + + rtems_bsd_rwlock_context_init(&context); + rtems_bsd_rwlock_isr_disable(isr_level, &context); + rtems_bsd_rwlock_acquire_critical(rw, &context); + + wowner = rtems_bsd_rwlock_wowner(rw); + + BSD_ASSERT(wowner == _Thread_Executing); + BSD_ASSERT(rw->nest_level == 0); + + rtems_bsd_rwlock_set_wowner(rw, NULL); + rw->readers = 1; + + if (__predict_true(_Thread_queue_Is_empty(&rw->reader_queue.Queue))) { + rtems_bsd_rwlock_release(rw, isr_level, &context); + } else { + rtems_bsd_rwlock_set_isr_level(&context, isr_level); + rtems_bsd_rwlock_ready_waiting_readers(rw, &context); + } +} + +static inline const char * +rtems_bsd_rwlock_name(const rtems_bsd_rwlock *rw) +{ + + return (rw->writer_queue.Queue.name); +} + +static inline void +rtems_bsd_rwlock_destroy(struct lock_object *lock, rtems_bsd_rwlock *rw) +{ + BSD_ASSERT(_Thread_queue_Is_empty(&rw->writer_queue.Queue)); + BSD_ASSERT(_Thread_queue_Is_empty(&rw->reader_queue.Queue)); + + if (rtems_bsd_rwlock_wowned(rw)) { + rw->nest_level = 0; + rtems_bsd_rwlock_wunlock(rw); + } + + _Thread_queue_Destroy(&rw->writer_queue); + _Thread_queue_Destroy(&rw->reader_queue); + lock_destroy(lock); +} + +#ifdef __cplusplus +} +#endif /* __cplusplus */ + +#endif /* _RTEMS_BSD_MACHINE_RTEMS_BSD_RWLOCKIMPL_H_ */ |