litmus-rt.git - The LITMUS^RT kernel.

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author	Linus Torvalds <torvalds@ppc970.osdl.org>	2005-06-20 14:37:49 -0400
committer	Linus Torvalds <torvalds@ppc970.osdl.org>	2005-06-20 14:37:49 -0400
commit	91b90475e793e84a57d956af8c52645e292badcb (patch)
tree	8de670e02f99a2a2bde82384104dcb8cb09cdadf /net/unix
parent	bcc408b75b707f46da1f81058ffa3c9df6f0170f (diff)
parent	f0ffeddc897a5cc5d5c6cc1b99a8799a8b34b28f (diff)

Merge master.kernel.org:/home/rmk/linux-2.6-arm

Diffstat (limited to 'net/unix')

0 files changed, 0 insertions, 0 deletions

#ifndef _ALPHA_RWSEM_H #define _ALPHA_RWSEM_H /* * Written by Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 2001. * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h */ #ifndef _LINUX_RWSEM_H #error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" #endif #ifdef __KERNEL__ #include <linux/compiler.h> #include <linux/list.h> #include <linux/spinlock.h> struct rwsem_waiter; extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *); extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); /* * the semaphore definition */ struct rw_semaphore { long count; #define RWSEM_UNLOCKED_VALUE 0x0000000000000000L #define RWSEM_ACTIVE_BIAS 0x0000000000000001L #define RWSEM_ACTIVE_MASK 0x00000000ffffffffL #define RWSEM_WAITING_BIAS (-0x0000000100000000L) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS #define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) spinlock_t wait_lock; struct list_head wait_list; }; #define __RWSEM_INITIALIZER(name) \ { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \ LIST_HEAD_INIT((name).wait_list) } #define DECLARE_RWSEM(name) \ struct rw_semaphore name = __RWSEM_INITIALIZER(name) static inline void init_rwsem(struct rw_semaphore *sem) { sem->count = RWSEM_UNLOCKED_VALUE; spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); } static inline void __down_read(struct rw_semaphore *sem) { long oldcount; #ifndef CONFIG_SMP oldcount = sem->count; sem->count += RWSEM_ACTIVE_READ_BIAS; #else long temp; __asm__ __volatile__( "1: ldq_l %0,%1\n" " addq %0,%3,%2\n" " stq_c %2,%1\n" " beq %2,2f\n" " mb\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory"); #endif if (unlikely(oldcount < 0)) rwsem_down_read_failed(sem); } /* * trylock for reading -- returns 1 if successful, 0 if contention */ static inline int __down_read_trylock(struct rw_semaphore *sem) { long old, new, res; res = sem->count; do { new = res + RWSEM_ACTIVE_READ_BIAS; if (new <= 0) break; old = res; res = cmpxchg(&sem->count, old, new); } while (res != old); return res >= 0 ? 1 : 0; } static inline void __down_write(struct rw_semaphore *sem) { long oldcount; #ifndef CONFIG_SMP oldcount = sem->count; sem->count += RWSEM_ACTIVE_WRITE_BIAS; #else long temp; __asm__ __volatile__( "1: ldq_l %0,%1\n" " addq %0,%3,%2\n" " stq_c %2,%1\n" " beq %2,2f\n" " mb\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory"); #endif if (unlikely(oldcount)) rwsem_down_write_failed(sem); } /* * trylock for writing -- returns 1 if successful, 0 if contention */ static inline int __down_write_trylock(struct rw_semaphore *sem) { long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, RWSEM_ACTIVE_WRITE_BIAS); if (ret == RWSEM_UNLOCKED_VALUE) return 1; return 0; } static inline void __up_read(struct rw_semaphore *sem) { long oldcount; #ifndef CONFIG_SMP oldcount = sem->count; sem->count -= RWSEM_ACTIVE_READ_BIAS; #else long temp; __asm__ __volatile__( " mb\n" "1: ldq_l %0,%1\n" " subq %0,%3,%2\n" " stq_c %2,%1\n" " beq %2,2f\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory"); #endif if (unlikely(oldcount < 0)) if ((int)oldcount - RWSEM_ACTIVE_READ_BIAS == 0) rwsem_wake(sem); } static inline void __up_write(struct rw_semaphore *sem) { long count; #ifndef CONFIG_SMP sem->count -= RWSEM_ACTIVE_WRITE_BIAS; count = sem->count; #else long temp; __asm__ __volatile__( " mb\n" "1: ldq_l %0,%1\n" " subq %0,%3,%2\n" " stq_c %2,%1\n" " beq %2,2f\n" " subq %0,%3,%0\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (count), "=m" (sem->count), "=&r" (temp) :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory"); #endif if (unlikely(count)) if ((int)count == 0) rwsem_wake(sem); } /* * downgrade write lock to read lock */ static inline void __downgrade_write(struct rw_semaphore *sem) { long oldcount; #ifndef CONFIG_SMP oldcount = sem->count; sem->count -= RWSEM_WAITING_BIAS; #else long temp; __asm__ __volatile__( "1: ldq_l %0,%1\n" " addq %0,%3,%2\n" " stq_c %2,%1\n" " beq %2,2f\n" " mb\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) :"Ir" (-RWSEM_WAITING_BIAS), "m" (sem->count) : "memory"); #endif if (unlikely(oldcount < 0)) rwsem_downgrade_wake(sem); } static inline void rwsem_atomic_add(long val, struct rw_semaphore *sem) { #ifndef CONFIG_SMP sem->count += val; #else long temp; __asm__ __volatile__( "1: ldq_l %0,%1\n" " addq %0,%2,%0\n" " stq_c %0,%1\n" " beq %0,2f\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (temp), "=m" (sem->count) :"Ir" (val), "m" (sem->count)); #endif } static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem) { #ifndef CONFIG_SMP sem->count += val; return sem->count; #else long ret, temp; __asm__ __volatile__( "1: ldq_l %0,%1\n" " addq %0,%3,%2\n" " addq %0,%3,%0\n" " stq_c %2,%1\n" " beq %2,2f\n" ".subsection 2\n" "2: br 1b\n" ".previous" :"=&r" (ret), "=m" (sem->count), "=&r" (temp) :"Ir" (val), "m" (sem->count)); return ret; #endif } static inline int rwsem_is_locked(struct rw_semaphore *sem) { return (sem->count != 0); } #endif /* __KERNEL__ */ #endif /* _ALPHA_RWSEM_H */


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