85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/*
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* rwsem.h: R/W semaphores implemented using CAS
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*
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* Written by David S. Miller (davem@redhat.com), 2001.
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* Derived from asm-i386/rwsem.h
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*/
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#ifndef _SPARC64_RWSEM_H
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#define _SPARC64_RWSEM_H
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#ifndef _LINUX_RWSEM_H
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#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
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#endif
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#ifdef __KERNEL__
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <asm/rwsem-const.h>
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struct rwsem_waiter;
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struct rw_semaphore {
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signed int count;
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spinlock_t wait_lock;
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struct list_head wait_list;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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};
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
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#else
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# define __RWSEM_DEP_MAP_INIT(lockname)
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#endif
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#define __RWSEM_INITIALIZER(name) \
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{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \
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__RWSEM_DEP_MAP_INIT(name) }
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#define DECLARE_RWSEM(name) \
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struct rw_semaphore name = __RWSEM_INITIALIZER(name)
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extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
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struct lock_class_key *key);
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#define init_rwsem(sem) \
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do { \
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static struct lock_class_key __key; \
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\
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__init_rwsem((sem), #sem, &__key); \
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} while (0)
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extern void __down_read(struct rw_semaphore *sem);
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extern int __down_read_trylock(struct rw_semaphore *sem);
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extern void __down_write(struct rw_semaphore *sem);
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extern int __down_write_trylock(struct rw_semaphore *sem);
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extern void __up_read(struct rw_semaphore *sem);
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extern void __up_write(struct rw_semaphore *sem);
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extern void __downgrade_write(struct rw_semaphore *sem);
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static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
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{
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__down_write(sem);
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}
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static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
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{
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return atomic_add_return(delta, (atomic_t *)(&sem->count));
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}
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static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
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{
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atomic_add(delta, (atomic_t *)(&sem->count));
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}
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static inline int rwsem_is_locked(struct rw_semaphore *sem)
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{
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return (sem->count != 0);
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}
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#endif /* __KERNEL__ */
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#endif /* _SPARC64_RWSEM_H */
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