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2023-12-08 01573e231f18eb2d99162747186f59511f56b64d

 kernel/kernel/locking/rwsem.h
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..
@@ -1,87 +0,0 @@
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-/* SPDX-License-Identifier: GPL-2.0 */
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-/*
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- * The owner field of the rw_semaphore structure will be set to
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- * RWSEM_READER_OWNED when a reader grabs the lock. A writer will clear
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- * the owner field when it unlocks. A reader, on the other hand, will
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- * not touch the owner field when it unlocks.
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- *
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- * In essence, the owner field now has the following 4 states:
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- *  1) 0
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- *     - lock is free or the owner hasn't set the field yet
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- *  2) RWSEM_READER_OWNED
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- *     - lock is currently or previously owned by readers (lock is free
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- *       or not set by owner yet)
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- *  3) RWSEM_ANONYMOUSLY_OWNED bit set with some other bits set as well
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- *     - lock is owned by an anonymous writer, so spinning on the lock
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- *       owner should be disabled.
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- *  4) Other non-zero value
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- *     - a writer owns the lock and other writers can spin on the lock owner.
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- */
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-#define RWSEM_ANONYMOUSLY_OWNED	(1UL << 0)
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-#define RWSEM_READER_OWNED	((struct task_struct *)RWSEM_ANONYMOUSLY_OWNED)
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-
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-#ifdef CONFIG_DEBUG_RWSEMS
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-# define DEBUG_RWSEMS_WARN_ON(c)	DEBUG_LOCKS_WARN_ON(c)
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-#else
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-# define DEBUG_RWSEMS_WARN_ON(c)
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-#endif
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-
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-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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-/*
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- * All writes to owner are protected by WRITE_ONCE() to make sure that
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- * store tearing can't happen as optimistic spinners may read and use
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- * the owner value concurrently without lock. Read from owner, however,
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- * may not need READ_ONCE() as long as the pointer value is only used
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- * for comparison and isn't being dereferenced.
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- */
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-static inline void rwsem_set_owner(struct rw_semaphore *sem)
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-{
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-	WRITE_ONCE(sem->owner, current);
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-}
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-
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-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
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-{
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-	WRITE_ONCE(sem->owner, NULL);
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-}
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-
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-static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
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-{
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-	/*
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-	 * We check the owner value first to make sure that we will only
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-	 * do a write to the rwsem cacheline when it is really necessary
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-	 * to minimize cacheline contention.
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-	 */
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-	if (READ_ONCE(sem->owner) != RWSEM_READER_OWNED)
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-		WRITE_ONCE(sem->owner, RWSEM_READER_OWNED);
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-}
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-
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-/*
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- * Return true if the a rwsem waiter can spin on the rwsem's owner
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- * and steal the lock, i.e. the lock is not anonymously owned.
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- * N.B. !owner is considered spinnable.
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- */
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-static inline bool is_rwsem_owner_spinnable(struct task_struct *owner)
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-{
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-	return !((unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED);
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-}
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-
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-/*
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- * Return true if rwsem is owned by an anonymous writer or readers.
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- */
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-static inline bool rwsem_has_anonymous_owner(struct task_struct *owner)
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-{
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-	return (unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED;
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-}
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-#else
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-static inline void rwsem_set_owner(struct rw_semaphore *sem)
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-{
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-}
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-
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-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
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-{
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-}
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-
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-static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
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-{
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-}
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-#endif