21  * Simple spin lock operations.  There are two variants, one clears IRQ's
28 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)  argument
33  * arch_spin_trylock - Try spin lock and return a result
34  * @lock: Pointer to the lock variable
36  * arch_spin_trylock() tries to get the lock and returns a result.
39 static inline int arch_spin_trylock(arch_spinlock_t *lock)  in arch_spin_trylock()  argument
45 	 * lock->slock :  =1 : unlock  in arch_spin_trylock()
46 	 *             : <=0 : lock  in arch_spin_trylock()
48 	 *   oldval = lock->slock; <--+ need atomic operation  in arch_spin_trylock()
49 	 *   lock->slock = 0;      <--+  in arch_spin_trylock()
58 		"lock	%0, @%3;		\n\t"  in arch_spin_trylock()
62 		: "r" (&lock->slock)  in arch_spin_trylock()
72 static inline void arch_spin_lock(arch_spinlock_t *lock)  in arch_spin_lock()  argument
77 	 * lock->slock :  =1 : unlock  in arch_spin_lock()
78 	 *             : <=0 : lock  in arch_spin_lock()
81 	 *   lock->slock -= 1;  <-- need atomic operation  in arch_spin_lock()
82 	 *   if (lock->slock == 0) break;  in arch_spin_lock()
83 	 *   for ( ; lock->slock <= 0 ; );  in arch_spin_lock()
93 		"lock	%0, @%2;		\n\t"  in arch_spin_lock()
106 		: "r" (&lock->slock)  in arch_spin_lock()
114 static inline void arch_spin_unlock(arch_spinlock_t *lock)  in arch_spin_unlock()  argument
117 	lock->slock = 1;  in arch_spin_unlock()
127  * irq-safe write-lock, but readers can get non-irqsafe
141  * @lock: the rwlock in question.
143 #define arch_read_can_lock(x) ((int)(x)->lock > 0)
147  * @lock: the rwlock in question.
149 #define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
156 	 * rw->lock :  >0 : unlock  in arch_read_lock()
157 	 *          : <=0 : lock  in arch_read_lock()
160 	 *   rw->lock -= 1;  <-- need atomic operation  in arch_read_lock()
161 	 *   if (rw->lock >= 0) break;  in arch_read_lock()
162 	 *   rw->lock += 1;  <-- need atomic operation  in arch_read_lock()
163 	 *   for ( ; rw->lock <= 0 ; );  in arch_read_lock()
173 		"lock	%0, @%2;		\n\t"  in arch_read_lock()
183 		"lock	%0, @%2;		\n\t"  in arch_read_lock()
194 		: "r" (&rw->lock)  in arch_read_lock()
207 	 * rw->lock :  =RW_LOCK_BIAS_STR : unlock  in arch_write_lock()
208 	 *          : !=RW_LOCK_BIAS_STR : lock  in arch_write_lock()
211 	 *   rw->lock -= RW_LOCK_BIAS_STR;  <-- need atomic operation  in arch_write_lock()
212 	 *   if (rw->lock == 0) break;  in arch_write_lock()
213 	 *   rw->lock += RW_LOCK_BIAS_STR;  <-- need atomic operation  in arch_write_lock()
214 	 *   for ( ; rw->lock != RW_LOCK_BIAS_STR ; ) ;  in arch_write_lock()
226 		"lock	%0, @%3;				\n\t"  in arch_write_lock()
236 		"lock	%0, @%3;				\n\t"  in arch_write_lock()
247 		: "r" (&rw->lock)  in arch_write_lock()
264 		"lock	%0, @%2;		\n\t"  in arch_read_unlock()
269 		: "r" (&rw->lock)  in arch_read_unlock()
288 		"lock	%0, @%3;				\n\t"  in arch_write_unlock()
293 		: "r" (&rw->lock)  in arch_write_unlock()
301 static inline int arch_read_trylock(arch_rwlock_t *lock)  in arch_read_trylock()  argument
303 	atomic_t *count = (atomic_t*)lock;  in arch_read_trylock()
310 static inline int arch_write_trylock(arch_rwlock_t *lock)  in arch_write_trylock()  argument
312 	atomic_t *count = (atomic_t *)lock;  in arch_write_trylock()
319 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)  argument
320 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)  argument
322 #define arch_spin_relax(lock)	cpu_relax()  argument
323 #define arch_read_relax(lock)	cpu_relax()  argument
324 #define arch_write_relax(lock)	cpu_relax()  argument