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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/rwsem-spinlock.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2v2.6.12-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-spinlock.h')
-rw-r--r-- | include/linux/rwsem-spinlock.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h new file mode 100644 index 000000000000..b52a2af25f1f --- /dev/null +++ b/include/linux/rwsem-spinlock.h @@ -0,0 +1,65 @@ +/* rwsem-spinlock.h: fallback C implementation + * + * Copyright (c) 2001 David Howells (dhowells@redhat.com). + * - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de> + * - Derived also from comments by Linus + */ + +#ifndef _LINUX_RWSEM_SPINLOCK_H +#define _LINUX_RWSEM_SPINLOCK_H + +#ifndef _LINUX_RWSEM_H +#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead" +#endif + +#include <linux/spinlock.h> +#include <linux/list.h> + +#ifdef __KERNEL__ + +#include <linux/types.h> + +struct rwsem_waiter; + +/* + * the rw-semaphore definition + * - if activity is 0 then there are no active readers or writers + * - if activity is +ve then that is the number of active readers + * - if activity is -1 then there is one active writer + * - if wait_list is not empty, then there are processes waiting for the semaphore + */ +struct rw_semaphore { + __s32 activity; + spinlock_t wait_lock; + struct list_head wait_list; +#if RWSEM_DEBUG + int debug; +#endif +}; + +/* + * initialisation + */ +#if RWSEM_DEBUG +#define __RWSEM_DEBUG_INIT , 0 +#else +#define __RWSEM_DEBUG_INIT /* */ +#endif + +#define __RWSEM_INITIALIZER(name) \ +{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT } + +#define DECLARE_RWSEM(name) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name) + +extern void FASTCALL(init_rwsem(struct rw_semaphore *sem)); +extern void FASTCALL(__down_read(struct rw_semaphore *sem)); +extern int FASTCALL(__down_read_trylock(struct rw_semaphore *sem)); +extern void FASTCALL(__down_write(struct rw_semaphore *sem)); +extern int FASTCALL(__down_write_trylock(struct rw_semaphore *sem)); +extern void FASTCALL(__up_read(struct rw_semaphore *sem)); +extern void FASTCALL(__up_write(struct rw_semaphore *sem)); +extern void FASTCALL(__downgrade_write(struct rw_semaphore *sem)); + +#endif /* __KERNEL__ */ +#endif /* _LINUX_RWSEM_SPINLOCK_H */ |