| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2000-2006 Silicon Graphics, Inc. |
| 3 | * All Rights Reserved. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it would be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write the Free Software Foundation, |
| 16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | #ifndef __XFS_SUPPORT_MRLOCK_H__ |
| 19 | #define __XFS_SUPPORT_MRLOCK_H__ |
| 20 | |
| 21 | #include <linux/rwsem.h> |
| 22 | |
| 23 | typedef struct { |
| 24 | struct rw_semaphore mr_lock; |
| 25 | #if defined(DEBUG) || defined(XFS_WARN) |
| 26 | int mr_writer; |
| 27 | #endif |
| 28 | } mrlock_t; |
| 29 | |
| 30 | #if defined(DEBUG) || defined(XFS_WARN) |
| 31 | #define mrinit(mrp, name) \ |
| 32 | do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0) |
| 33 | #else |
| 34 | #define mrinit(mrp, name) \ |
| 35 | do { init_rwsem(&(mrp)->mr_lock); } while (0) |
| 36 | #endif |
| 37 | |
| 38 | #define mrlock_init(mrp, t,n,s) mrinit(mrp, n) |
| 39 | #define mrfree(mrp) do { } while (0) |
| 40 | |
| 41 | static inline void mraccess_nested(mrlock_t *mrp, int subclass) |
| 42 | { |
| 43 | down_read_nested(&mrp->mr_lock, subclass); |
| 44 | } |
| 45 | |
| 46 | static inline void mrupdate_nested(mrlock_t *mrp, int subclass) |
| 47 | { |
| 48 | down_write_nested(&mrp->mr_lock, subclass); |
| 49 | #if defined(DEBUG) || defined(XFS_WARN) |
| 50 | mrp->mr_writer = 1; |
| 51 | #endif |
| 52 | } |
| 53 | |
| 54 | static inline int mrtryaccess(mrlock_t *mrp) |
| 55 | { |
| 56 | return down_read_trylock(&mrp->mr_lock); |
| 57 | } |
| 58 | |
| 59 | static inline int mrtryupdate(mrlock_t *mrp) |
| 60 | { |
| 61 | if (!down_write_trylock(&mrp->mr_lock)) |
| 62 | return 0; |
| 63 | #if defined(DEBUG) || defined(XFS_WARN) |
| 64 | mrp->mr_writer = 1; |
| 65 | #endif |
| 66 | return 1; |
| 67 | } |
| 68 | |
| 69 | static inline void mrunlock_excl(mrlock_t *mrp) |
| 70 | { |
| 71 | #if defined(DEBUG) || defined(XFS_WARN) |
| 72 | mrp->mr_writer = 0; |
| 73 | #endif |
| 74 | up_write(&mrp->mr_lock); |
| 75 | } |
| 76 | |
| 77 | static inline void mrunlock_shared(mrlock_t *mrp) |
| 78 | { |
| 79 | up_read(&mrp->mr_lock); |
| 80 | } |
| 81 | |
| 82 | static inline void mrdemote(mrlock_t *mrp) |
| 83 | { |
| 84 | #if defined(DEBUG) || defined(XFS_WARN) |
| 85 | mrp->mr_writer = 0; |
| 86 | #endif |
| 87 | downgrade_write(&mrp->mr_lock); |
| 88 | } |
| 89 | |
| 90 | #endif /* __XFS_SUPPORT_MRLOCK_H__ */ |