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author | Ingo Molnar <mingo@elte.hu> | 2006-07-03 09:24:29 +0200 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-04 00:27:01 +0200 |
commit | c4e05116a2c4d8187127dbf77ab790aa57a47388 (patch) | |
tree | 58f07aed47ee4d30e9588d5a820c245faa163b09 /kernel/rwsem.c | |
parent | [PATCH] lockdep: add DECLARE_COMPLETION_ONSTACK() API (diff) | |
download | linux-c4e05116a2c4d8187127dbf77ab790aa57a47388.tar.xz linux-c4e05116a2c4d8187127dbf77ab790aa57a47388.zip |
[PATCH] lockdep: clean up rwsems
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>
Diffstat (limited to 'kernel/rwsem.c')
-rw-r--r-- | kernel/rwsem.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/kernel/rwsem.c b/kernel/rwsem.c new file mode 100644 index 000000000000..790a99bb25aa --- /dev/null +++ b/kernel/rwsem.c @@ -0,0 +1,105 @@ +/* kernel/rwsem.c: R/W semaphores, public implementation + * + * Written by David Howells (dhowells@redhat.com). + * Derived from asm-i386/semaphore.h + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/rwsem.h> + +#include <asm/system.h> +#include <asm/atomic.h> + +/* + * lock for reading + */ +void down_read(struct rw_semaphore *sem) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); + + __down_read(sem); +} + +EXPORT_SYMBOL(down_read); + +/* + * trylock for reading -- returns 1 if successful, 0 if contention + */ +int down_read_trylock(struct rw_semaphore *sem) +{ + int ret = __down_read_trylock(sem); + + if (ret == 1) + rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); + return ret; +} + +EXPORT_SYMBOL(down_read_trylock); + +/* + * lock for writing + */ +void down_write(struct rw_semaphore *sem) +{ + might_sleep(); + rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); + + __down_write(sem); +} + +EXPORT_SYMBOL(down_write); + +/* + * trylock for writing -- returns 1 if successful, 0 if contention + */ +int down_write_trylock(struct rw_semaphore *sem) +{ + int ret = __down_write_trylock(sem); + + if (ret == 1) + rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); + return ret; +} + +EXPORT_SYMBOL(down_write_trylock); + +/* + * release a read lock + */ +void up_read(struct rw_semaphore *sem) +{ + rwsem_release(&sem->dep_map, 1, _RET_IP_); + + __up_read(sem); +} + +EXPORT_SYMBOL(up_read); + +/* + * release a write lock + */ +void up_write(struct rw_semaphore *sem) +{ + rwsem_release(&sem->dep_map, 1, _RET_IP_); + + __up_write(sem); +} + +EXPORT_SYMBOL(up_write); + +/* + * downgrade write lock to read lock + */ +void downgrade_write(struct rw_semaphore *sem) +{ + /* + * lockdep: a downgraded write will live on as a write + * dependency. + */ + __downgrade_write(sem); +} + +EXPORT_SYMBOL(downgrade_write); |