1da177e4c3
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!
259 lines
6.7 KiB
C
259 lines
6.7 KiB
C
#ifndef __ASM_SPINLOCK_H
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#define __ASM_SPINLOCK_H
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#include <asm/system.h>
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/* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked
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* since it only has load-and-zero. Moreover, at least on some PA processors,
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* the semaphore address has to be 16-byte aligned.
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*/
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#ifndef CONFIG_DEBUG_SPINLOCK
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#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 } }
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#undef SPIN_LOCK_UNLOCKED
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#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
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#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
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static inline int spin_is_locked(spinlock_t *x)
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{
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volatile unsigned int *a = __ldcw_align(x);
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return *a == 0;
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}
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#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
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#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
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static inline void _raw_spin_lock(spinlock_t *x)
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{
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volatile unsigned int *a;
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mb();
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a = __ldcw_align(x);
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while (__ldcw(a) == 0)
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while (*a == 0);
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mb();
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}
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static inline void _raw_spin_unlock(spinlock_t *x)
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{
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volatile unsigned int *a;
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mb();
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a = __ldcw_align(x);
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*a = 1;
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mb();
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}
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static inline int _raw_spin_trylock(spinlock_t *x)
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{
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volatile unsigned int *a;
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int ret;
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mb();
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a = __ldcw_align(x);
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ret = __ldcw(a) != 0;
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mb();
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return ret;
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}
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#define spin_lock_own(LOCK, LOCATION) ((void)0)
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#else /* !(CONFIG_DEBUG_SPINLOCK) */
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#define SPINLOCK_MAGIC 0x1D244B3C
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#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL }
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#undef SPIN_LOCK_UNLOCKED
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#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
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#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
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#define CHECK_LOCK(x) \
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do { \
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if (unlikely((x)->magic != SPINLOCK_MAGIC)) { \
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printk(KERN_ERR "%s:%d: spin_is_locked" \
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" on uninitialized spinlock %p.\n", \
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__FILE__, __LINE__, (x)); \
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} \
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} while(0)
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#define spin_is_locked(x) \
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({ \
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CHECK_LOCK(x); \
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volatile unsigned int *a = __ldcw_align(x); \
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if (unlikely((*a == 0) && (x)->babble)) { \
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(x)->babble--; \
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printk("KERN_WARNING \
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%s:%d: spin_is_locked(%s/%p) already" \
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" locked by %s:%d in %s at %p(%d)\n", \
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__FILE__,__LINE__, (x)->module, (x), \
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(x)->bfile, (x)->bline, (x)->task->comm,\
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(x)->previous, (x)->oncpu); \
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} \
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*a == 0; \
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})
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#define spin_unlock_wait(x) \
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do { \
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CHECK_LOCK(x); \
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volatile unsigned int *a = __ldcw_align(x); \
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if (unlikely((*a == 0) && (x)->babble)) { \
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(x)->babble--; \
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printk("KERN_WARNING \
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%s:%d: spin_unlock_wait(%s/%p)" \
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" owned by %s:%d in %s at %p(%d)\n", \
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__FILE__,__LINE__, (x)->module, (x), \
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(x)->bfile, (x)->bline, (x)->task->comm,\
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(x)->previous, (x)->oncpu); \
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} \
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barrier(); \
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} while (*((volatile unsigned char *)(__ldcw_align(x))) == 0)
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extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no);
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extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int);
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extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int);
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#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
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#define _raw_spin_unlock(lock) _dbg_spin_unlock(lock, __FILE__, __LINE__)
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#define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__)
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#define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__)
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/* just in case we need it */
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#define spin_lock_own(LOCK, LOCATION) \
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do { \
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volatile unsigned int *a = __ldcw_align(LOCK); \
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if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id()))) \
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printk("KERN_WARNING \
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%s: called on %d from %p but lock %s on %d\n", \
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LOCATION, smp_processor_id(), \
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__builtin_return_address(0), \
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(*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \
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} while (0)
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#endif /* !(CONFIG_DEBUG_SPINLOCK) */
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/*
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* Read-write spinlocks, allowing multiple readers
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* but only one writer.
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*/
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typedef struct {
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spinlock_t lock;
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volatile int counter;
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#ifdef CONFIG_PREEMPT
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unsigned int break_lock;
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#endif
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} rwlock_t;
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#define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 }
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#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)
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#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
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/* read_lock, read_unlock are pretty straightforward. Of course it somehow
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* sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */
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#ifdef CONFIG_DEBUG_RWLOCK
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extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__)
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#else
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static __inline__ void _raw_read_lock(rwlock_t *rw)
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{
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unsigned long flags;
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local_irq_save(flags);
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_raw_spin_lock(&rw->lock);
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rw->counter++;
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_raw_spin_unlock(&rw->lock);
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local_irq_restore(flags);
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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static __inline__ void _raw_read_unlock(rwlock_t *rw)
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{
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unsigned long flags;
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local_irq_save(flags);
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_raw_spin_lock(&rw->lock);
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rw->counter--;
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_raw_spin_unlock(&rw->lock);
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local_irq_restore(flags);
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}
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/* write_lock is less trivial. We optimistically grab the lock and check
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* if we surprised any readers. If so we release the lock and wait till
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* they're all gone before trying again
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*
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* Also note that we don't use the _irqsave / _irqrestore suffixes here.
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* If we're called with interrupts enabled and we've got readers (or other
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* writers) in interrupt handlers someone fucked up and we'd dead-lock
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* sooner or later anyway. prumpf */
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#ifdef CONFIG_DEBUG_RWLOCK
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extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__)
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#else
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static __inline__ void _raw_write_lock(rwlock_t *rw)
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{
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retry:
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_raw_spin_lock(&rw->lock);
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if(rw->counter != 0) {
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/* this basically never happens */
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_raw_spin_unlock(&rw->lock);
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while(rw->counter != 0);
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goto retry;
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}
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/* got it. now leave without unlocking */
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rw->counter = -1; /* remember we are locked */
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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/* write_unlock is absolutely trivial - we don't have to wait for anything */
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static __inline__ void _raw_write_unlock(rwlock_t *rw)
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{
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rw->counter = 0;
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_raw_spin_unlock(&rw->lock);
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}
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#ifdef CONFIG_DEBUG_RWLOCK
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extern int _dbg_write_trylock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_write_trylock(rw) _dbg_write_trylock(rw, __FILE__, __LINE__)
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#else
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static __inline__ int _raw_write_trylock(rwlock_t *rw)
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{
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_raw_spin_lock(&rw->lock);
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if (rw->counter != 0) {
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/* this basically never happens */
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_raw_spin_unlock(&rw->lock);
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return 0;
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}
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/* got it. now leave without unlocking */
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rw->counter = -1; /* remember we are locked */
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return 1;
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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static __inline__ int is_read_locked(rwlock_t *rw)
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{
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return rw->counter > 0;
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}
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static __inline__ int is_write_locked(rwlock_t *rw)
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{
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return rw->counter < 0;
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}
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#endif /* __ASM_SPINLOCK_H */
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