| 1 | #ifndef _LINUX_PERCPU_RWSEM_H
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| 2 | #define _LINUX_PERCPU_RWSEM_H
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| 3 |
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| 4 | #include <linux/atomic.h>
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| 5 | #include <linux/rwsem.h>
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| 6 | #include <linux/percpu.h>
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| 7 | #include <linux/wait.h>
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| 8 | #include <linux/rcu_sync.h>
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| 9 | #include <linux/lockdep.h>
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| 10 |
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| 11 | struct percpu_rw_semaphore {
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| 12 | struct rcu_sync rss;
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| 13 | unsigned int __percpu *fast_read_ctr;
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| 14 | struct rw_semaphore rw_sem;
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| 15 | atomic_t slow_read_ctr;
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| 16 | wait_queue_head_t write_waitq;
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| 17 | };
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| 18 |
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| 19 | extern void percpu_down_read(struct percpu_rw_semaphore *);
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| 20 | extern int percpu_down_read_trylock(struct percpu_rw_semaphore *);
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| 21 | extern void percpu_up_read(struct percpu_rw_semaphore *);
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| 22 |
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| 23 | extern void percpu_down_write(struct percpu_rw_semaphore *);
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| 24 | extern void percpu_up_write(struct percpu_rw_semaphore *);
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| 25 |
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| 26 | extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
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| 27 | const char *, struct lock_class_key *);
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| 28 | extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
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| 29 |
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| 30 | #define percpu_init_rwsem(brw) \
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| 31 | ({ \
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| 32 | static struct lock_class_key rwsem_key; \
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| 33 | __percpu_init_rwsem(brw, #brw, &rwsem_key); \
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| 34 | })
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| 35 |
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| 36 |
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| 37 | #define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
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| 38 |
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| 39 | static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
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| 40 | bool read, unsigned long ip)
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| 41 | {
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| 42 | lock_release(&sem->rw_sem.dep_map, 1, ip);
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| 43 | #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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| 44 | if (!read)
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| 45 | sem->rw_sem.owner = NULL;
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| 46 | #endif
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| 47 | }
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| 48 |
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| 49 | static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
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| 50 | bool read, unsigned long ip)
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| 51 | {
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| 52 | lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
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| 53 | }
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| 54 |
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| 55 | #endif
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