c4e05116a2
Clean up rwsems. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
91 lines
1.5 KiB
C
91 lines
1.5 KiB
C
/* rwsem.h: R/W semaphores, public interface
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*
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* Written by David Howells (dhowells@redhat.com).
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* Derived from asm-i386/semaphore.h
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*/
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#ifndef _LINUX_RWSEM_H
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#define _LINUX_RWSEM_H
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#include <linux/linkage.h>
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#ifdef __KERNEL__
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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struct rw_semaphore;
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#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
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#include <linux/rwsem-spinlock.h> /* use a generic implementation */
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#else
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#include <asm/rwsem.h> /* use an arch-specific implementation */
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#endif
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/*
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* lock for reading
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*/
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static inline void down_read(struct rw_semaphore *sem)
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{
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might_sleep();
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__down_read(sem);
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}
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/*
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* trylock for reading -- returns 1 if successful, 0 if contention
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*/
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static inline int down_read_trylock(struct rw_semaphore *sem)
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{
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int ret;
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ret = __down_read_trylock(sem);
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return ret;
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}
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/*
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* lock for writing
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*/
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static inline void down_write(struct rw_semaphore *sem)
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{
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might_sleep();
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__down_write(sem);
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}
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/*
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* trylock for writing -- returns 1 if successful, 0 if contention
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*/
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static inline int down_write_trylock(struct rw_semaphore *sem)
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{
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int ret;
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ret = __down_write_trylock(sem);
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return ret;
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}
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/*
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* release a read lock
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*/
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static inline void up_read(struct rw_semaphore *sem)
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{
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__up_read(sem);
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}
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/*
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* release a write lock
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*/
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static inline void up_write(struct rw_semaphore *sem)
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{
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__up_write(sem);
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}
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/*
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* downgrade write lock to read lock
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*/
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static inline void downgrade_write(struct rw_semaphore *sem)
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{
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__downgrade_write(sem);
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_RWSEM_H */
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