| // 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__ */ |