percpu-rwsem: introduce percpu_rwsem_release() and percpu_rwsem_acquire() (55cc1565) · Commits · 戴 / test

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>

include/linux/percpu-rwsem.h

+19 −0

Original line number	Diff line number	Diff line
		@@ -32,4 +32,23 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
		__percpu_init_rwsem(brw, #brw, &rwsem_key); \
		})


		#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)

		static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
		bool read, unsigned long ip)
		{
		lock_release(&sem->rw_sem.dep_map, 1, ip);
		#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
		if (!read)
		sem->rw_sem.owner = NULL;
		#endif
		}

		static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
		bool read, unsigned long ip)
		{
		lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
		}

		#endif

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