diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/rwsem.h |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/rwsem.h')
-rw-r--r-- | include/linux/rwsem.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h new file mode 100644 index 00000000000..bfb98888500 --- /dev/null +++ b/include/linux/rwsem.h @@ -0,0 +1,115 @@ +/* rwsem.h: R/W semaphores, public interface + * + * Written by David Howells (dhowells@redhat.com). + * Derived from asm-i386/semaphore.h + */ + +#ifndef _LINUX_RWSEM_H +#define _LINUX_RWSEM_H + +#include <linux/linkage.h> + +#define RWSEM_DEBUG 0 + +#ifdef __KERNEL__ + +#include <linux/config.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <asm/system.h> +#include <asm/atomic.h> + +struct rw_semaphore; + +#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK +#include <linux/rwsem-spinlock.h> /* use a generic implementation */ +#else +#include <asm/rwsem.h> /* use an arch-specific implementation */ +#endif + +#ifndef rwsemtrace +#if RWSEM_DEBUG +extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str)); +#else +#define rwsemtrace(SEM,FMT) +#endif +#endif + +/* + * lock for reading + */ +static inline void down_read(struct rw_semaphore *sem) +{ + might_sleep(); + rwsemtrace(sem,"Entering down_read"); + __down_read(sem); + rwsemtrace(sem,"Leaving down_read"); +} + +/* + * trylock for reading -- returns 1 if successful, 0 if contention + */ +static inline int down_read_trylock(struct rw_semaphore *sem) +{ + int ret; + rwsemtrace(sem,"Entering down_read_trylock"); + ret = __down_read_trylock(sem); + rwsemtrace(sem,"Leaving down_read_trylock"); + return ret; +} + +/* + * lock for writing + */ +static inline void down_write(struct rw_semaphore *sem) +{ + might_sleep(); + rwsemtrace(sem,"Entering down_write"); + __down_write(sem); + rwsemtrace(sem,"Leaving down_write"); +} + +/* + * trylock for writing -- returns 1 if successful, 0 if contention + */ +static inline int down_write_trylock(struct rw_semaphore *sem) +{ + int ret; + rwsemtrace(sem,"Entering down_write_trylock"); + ret = __down_write_trylock(sem); + rwsemtrace(sem,"Leaving down_write_trylock"); + return ret; +} + +/* + * release a read lock + */ +static inline void up_read(struct rw_semaphore *sem) +{ + rwsemtrace(sem,"Entering up_read"); + __up_read(sem); + rwsemtrace(sem,"Leaving up_read"); +} + +/* + * release a write lock + */ +static inline void up_write(struct rw_semaphore *sem) +{ + rwsemtrace(sem,"Entering up_write"); + __up_write(sem); + rwsemtrace(sem,"Leaving up_write"); +} + +/* + * downgrade write lock to read lock + */ +static inline void downgrade_write(struct rw_semaphore *sem) +{ + rwsemtrace(sem,"Entering downgrade_write"); + __downgrade_write(sem); + rwsemtrace(sem,"Leaving downgrade_write"); +} + +#endif /* __KERNEL__ */ +#endif /* _LINUX_RWSEM_H */ |