diff options
Diffstat (limited to 'include/sys')
| -rw-r--r-- | include/sys/rwlock.h | 121 |
1 files changed, 71 insertions, 50 deletions
diff --git a/include/sys/rwlock.h b/include/sys/rwlock.h index 2e8624191..c6d66ceaa 100644 --- a/include/sys/rwlock.h +++ b/include/sys/rwlock.h @@ -1,7 +1,7 @@ /* * This file is part of the SPL: Solaris Porting Layer. * - * Copyright (c) 2008 Lawrence Livermore National Security, LLC. + * Copyright (c) 2009 Lawrence Livermore National Security, LLC. * Produced at Lawrence Livermore National Laboratory * Written by: * Brian Behlendorf <[email protected]>, @@ -30,68 +30,89 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/rwsem.h> -#include <asm/current.h> #include <sys/types.h> -#include <sys/kmem.h> - -#ifdef __cplusplus -extern "C" { -#endif typedef enum { - RW_DRIVER = 2, /* driver (DDI) rwlock */ - RW_DEFAULT = 4 /* kernel default rwlock */ + RW_DRIVER = 2, + RW_DEFAULT = 4 } krw_type_t; typedef enum { - RW_WRITER, - RW_READER + RW_NONE = 0, + RW_WRITER = 1, + RW_READER = 2 } krw_t; +typedef struct rw_semaphore krwlock_t; -#define RW_MAGIC 0x3423645a -#define RW_POISON 0xa6 +#define rw_init(rwlp, name, type, arg) init_rwsem(rwlp) +#define rw_destroy(rwlp) ((void)0) +#define rw_downgrade(rwlp) downgrade_write(rwlp) +#define RW_LOCK_HELD(rwlp) rwsem_is_locked(rwlp) +/* + * the rw-semaphore definition + * - if activity/count is 0 then there are no active readers or writers + * - if activity/count is +ve then that is the number of active readers + * - if activity/count is -1 then there is one active writer + */ +#if defined(CONFIG_RWSEM_GENERIC_SPINLOCK) +# define RW_COUNT(rwlp) ((rwlp)->activity) +# define RW_READ_HELD(rwlp) ((RW_COUNT(rwlp) > 0) ? RW_COUNT(rwlp) : 0) +# define RW_WRITE_HELD(rwlp) ((RW_COUNT(rwlp) < 0)) +# define rw_exit_locked(rwlp) __up_read_locked(rwlp) +# define rw_tryenter_locked(rwlp) __down_write_trylock_locked(rwlp) +void __up_read_locked(struct rw_semaphore *); +int __down_write_trylock_locked(struct rw_semaphore *); +#else +# define RW_COUNT(rwlp) ((rwlp)->count & RWSEM_ACTIVE_MASK) +# define RW_READ_HELD(rwlp) ((RW_COUNT(rwlp) > 0) ? RW_COUNT(rwlp) : 0) +# define RW_WRITE_HELD(rwlp) ((RW_COUNT(rwlp) < 0)) +# define rw_exit_locked(rwlp) up_read(rwlp) +# define rw_tryenter_locked(rwlp) down_write_trylock(rwlp) +#endif -typedef struct { - int32_t rw_magic; - int32_t rw_name_size; - char *rw_name; - struct rw_semaphore rw_sem; - struct task_struct *rw_owner; /* holder of the write lock */ -} krwlock_t; +#define rw_tryenter(rwlp, rw) \ +({ \ + int _rc_ = 0; \ + switch (rw) { \ + case RW_READER: _rc_ = down_read_trylock(rwlp); break; \ + case RW_WRITER: _rc_ = down_write_trylock(rwlp); break; \ + default: SBUG(); \ + } \ + _rc_; \ +}) -extern void __rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg); -extern void __rw_destroy(krwlock_t *rwlp); -extern int __rw_tryenter(krwlock_t *rwlp, krw_t rw); -extern void __rw_enter(krwlock_t *rwlp, krw_t rw); -extern void __rw_exit(krwlock_t *rwlp); -extern void __rw_downgrade(krwlock_t *rwlp); -extern int __rw_tryupgrade(krwlock_t *rwlp); -extern kthread_t *__rw_owner(krwlock_t *rwlp); -extern int __rw_read_held(krwlock_t *rwlp); -extern int __rw_write_held(krwlock_t *rwlp); -extern int __rw_lock_held(krwlock_t *rwlp); +#define rw_enter(rwlp, rw) \ +({ \ + switch (rw) { \ + case RW_READER: down_read(rwlp); break; \ + case RW_WRITER: down_write(rwlp); break; \ + default: SBUG(); \ + } \ +}) -#define rw_init(rwlp, name, type, arg) \ -({ \ - if ((name) == NULL) \ - __rw_init(rwlp, #rwlp, type, arg); \ - else \ - __rw_init(rwlp, name, type, arg); \ +#define rw_exit(rwlp) \ +({ \ + if (RW_READ_HELD(rwlp)) \ + up_read(rwlp); \ + else if (RW_WRITE_HELD(rwlp)) \ + up_write(rwlp); \ + else \ + SBUG(); \ }) -#define rw_destroy(rwlp) __rw_destroy(rwlp) -#define rw_tryenter(rwlp, rw) __rw_tryenter(rwlp, rw) -#define rw_enter(rwlp, rw) __rw_enter(rwlp, rw) -#define rw_exit(rwlp) __rw_exit(rwlp) -#define rw_downgrade(rwlp) __rw_downgrade(rwlp) -#define rw_tryupgrade(rwlp) __rw_tryupgrade(rwlp) -#define rw_owner(rwlp) __rw_owner(rwlp) -#define RW_READ_HELD(rwlp) __rw_read_held(rwlp) -#define RW_WRITE_HELD(rwlp) __rw_write_held(rwlp) -#define RW_LOCK_HELD(rwlp) __rw_lock_held(rwlp) -#ifdef __cplusplus -} -#endif +#define rw_tryupgrade(rwlp) \ +({ \ + unsigned long flags; \ + int _rc_ = 0; \ + spin_lock_irqsave(&(rwlp)->wait_lock, flags); \ + if (list_empty(&(rwlp)->wait_list) && (RW_READ_HELD(rwlp) == 1)) { \ + rw_exit_locked(rwlp); \ + _rc_ = rw_tryenter_locked(rwlp); \ + ASSERT(_rc_); \ + } \ + spin_unlock_irqrestore(&(rwlp)->wait_lock, flags); \ + _rc_; \ +}) #endif /* _SPL_RWLOCK_H */ |