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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (c) 2000-2006 Silicon Graphics, Inc.
- * All Rights Reserved.
- */
- #ifndef __XFS_SUPPORT_MRLOCK_H__
- #define __XFS_SUPPORT_MRLOCK_H__
- #include <linux/rwsem.h>
- typedef struct {
- struct rw_semaphore mr_lock;
- #if defined(DEBUG) || defined(XFS_WARN)
- int mr_writer;
- #endif
- } mrlock_t;
- #if defined(DEBUG) || defined(XFS_WARN)
- #define mrinit(mrp, name) \
- do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
- #else
- #define mrinit(mrp, name) \
- do { init_rwsem(&(mrp)->mr_lock); } while (0)
- #endif
- #define mrlock_init(mrp, t,n,s) mrinit(mrp, n)
- #define mrfree(mrp) do { } while (0)
- static inline void mraccess_nested(mrlock_t *mrp, int subclass)
- {
- down_read_nested(&mrp->mr_lock, subclass);
- }
- static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
- {
- down_write_nested(&mrp->mr_lock, subclass);
- #if defined(DEBUG) || defined(XFS_WARN)
- mrp->mr_writer = 1;
- #endif
- }
- static inline int mrtryaccess(mrlock_t *mrp)
- {
- return down_read_trylock(&mrp->mr_lock);
- }
- static inline int mrtryupdate(mrlock_t *mrp)
- {
- if (!down_write_trylock(&mrp->mr_lock))
- return 0;
- #if defined(DEBUG) || defined(XFS_WARN)
- mrp->mr_writer = 1;
- #endif
- return 1;
- }
- static inline void mrunlock_excl(mrlock_t *mrp)
- {
- #if defined(DEBUG) || defined(XFS_WARN)
- mrp->mr_writer = 0;
- #endif
- up_write(&mrp->mr_lock);
- }
- static inline void mrunlock_shared(mrlock_t *mrp)
- {
- up_read(&mrp->mr_lock);
- }
- static inline void mrdemote(mrlock_t *mrp)
- {
- #if defined(DEBUG) || defined(XFS_WARN)
- mrp->mr_writer = 0;
- #endif
- downgrade_write(&mrp->mr_lock);
- }
- #endif /* __XFS_SUPPORT_MRLOCK_H__ */
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