Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | /* 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 */ |