![Oleg Nesterov](/assets/img/avatar_default.png)
Add percpu_rwsem_release() and percpu_rwsem_acquire() for the users which need to return to userspace with percpu-rwsem lock held and/or pass the ownership to another thread. TODO: change percpu_rwsem_release() to use rwsem_clear_owner(). We can either fold kernel/locking/rwsem.h into include/linux/rwsem.h, or add the non-inline percpu_rwsem_clear_owner(). Signed-off-by: Oleg Nesterov <oleg@redhat.com>
55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
#ifndef _LINUX_PERCPU_RWSEM_H
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#define _LINUX_PERCPU_RWSEM_H
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#include <linux/atomic.h>
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#include <linux/rwsem.h>
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#include <linux/percpu.h>
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#include <linux/wait.h>
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#include <linux/lockdep.h>
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struct percpu_rw_semaphore {
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unsigned int __percpu *fast_read_ctr;
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atomic_t write_ctr;
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struct rw_semaphore rw_sem;
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atomic_t slow_read_ctr;
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wait_queue_head_t write_waitq;
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};
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extern void percpu_down_read(struct percpu_rw_semaphore *);
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extern int percpu_down_read_trylock(struct percpu_rw_semaphore *);
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extern void percpu_up_read(struct percpu_rw_semaphore *);
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extern void percpu_down_write(struct percpu_rw_semaphore *);
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extern void percpu_up_write(struct percpu_rw_semaphore *);
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extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
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const char *, struct lock_class_key *);
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extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
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#define percpu_init_rwsem(brw) \
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({ \
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static struct lock_class_key rwsem_key; \
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__percpu_init_rwsem(brw, #brw, &rwsem_key); \
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})
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#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
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static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
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bool read, unsigned long ip)
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{
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lock_release(&sem->rw_sem.dep_map, 1, ip);
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#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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if (!read)
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sem->rw_sem.owner = NULL;
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#endif
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}
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static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
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bool read, unsigned long ip)
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{
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lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
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}
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#endif
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