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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - fs/aufs/rwsem.h
2 * Copyright (C) 2005-2017 Junjiro R. Okajima
4 * This program, aufs is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will 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.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 * simple read-write semaphore wrappers
22 #ifndef __AUFS_RWSEM_H__
23 #define __AUFS_RWSEM_H__
30 struct rw_semaphore rwsem
;
31 #ifdef CONFIG_AUFS_DEBUG
32 /* just for debugging, not almighty counter */
38 #define au_lockdep_set_name(rw) \
39 lockdep_set_class_and_name(&(rw)->rwsem, \
40 /*original key*/(rw)->rwsem.dep_map.key, \
43 #define au_lockdep_set_name(rw) do {} while (0)
46 #ifdef CONFIG_AUFS_DEBUG
47 #define AuDbgCntInit(rw) do { \
48 atomic_set(&(rw)->rcnt, 0); \
49 atomic_set(&(rw)->wcnt, 0); \
50 smp_mb(); /* atomic set */ \
53 #define AuDbgCnt(rw, cnt) atomic_read(&(rw)->cnt)
54 #define AuDbgCntInc(rw, cnt) atomic_inc(&(rw)->cnt)
55 #define AuDbgCntDec(rw, cnt) WARN_ON(atomic_dec_return(&(rw)->cnt) < 0)
56 #define AuDbgRcntInc(rw) AuDbgCntInc(rw, rcnt)
57 #define AuDbgRcntDec(rw) AuDbgCntDec(rw, rcnt)
58 #define AuDbgWcntInc(rw) AuDbgCntInc(rw, wcnt)
59 #define AuDbgWcntDec(rw) AuDbgCntDec(rw, wcnt)
61 #define AuDbgCnt(rw, cnt) 0
62 #define AuDbgCntInit(rw) do {} while (0)
63 #define AuDbgRcntInc(rw) do {} while (0)
64 #define AuDbgRcntDec(rw) do {} while (0)
65 #define AuDbgWcntInc(rw) do {} while (0)
66 #define AuDbgWcntDec(rw) do {} while (0)
67 #endif /* CONFIG_AUFS_DEBUG */
69 /* to debug easier, do not make them inlined functions */
70 #define AuRwMustNoWaiters(rw) AuDebugOn(rwsem_is_contended(&(rw)->rwsem))
71 /* rwsem_is_locked() is unusable */
72 #define AuRwMustReadLock(rw) AuDebugOn(AuDbgCnt(rw, rcnt) <= 0)
73 #define AuRwMustWriteLock(rw) AuDebugOn(AuDbgCnt(rw, wcnt) <= 0)
74 #define AuRwMustAnyLock(rw) AuDebugOn(AuDbgCnt(rw, rcnt) <= 0 \
75 && AuDbgCnt(rw, wcnt) <= 0)
76 #define AuRwDestroy(rw) AuDebugOn(AuDbgCnt(rw, rcnt) \
77 || AuDbgCnt(rw, wcnt))
79 #define au_rw_init(rw) do { \
81 init_rwsem(&(rw)->rwsem); \
82 au_lockdep_set_name(rw); \
85 #define au_rw_init_wlock(rw) do { \
87 down_write(&(rw)->rwsem); \
91 #define au_rw_init_wlock_nested(rw, lsc) do { \
93 down_write_nested(&(rw)->rwsem, lsc); \
97 static inline void au_rw_read_lock(struct au_rwsem
*rw
)
99 down_read(&rw
->rwsem
);
103 static inline void au_rw_read_lock_nested(struct au_rwsem
*rw
, unsigned int lsc
)
105 down_read_nested(&rw
->rwsem
, lsc
);
109 static inline void au_rw_read_unlock(struct au_rwsem
*rw
)
111 AuRwMustReadLock(rw
);
116 static inline void au_rw_dgrade_lock(struct au_rwsem
*rw
)
118 AuRwMustWriteLock(rw
);
121 downgrade_write(&rw
->rwsem
);
124 static inline void au_rw_write_lock(struct au_rwsem
*rw
)
126 down_write(&rw
->rwsem
);
130 static inline void au_rw_write_lock_nested(struct au_rwsem
*rw
,
133 down_write_nested(&rw
->rwsem
, lsc
);
137 static inline void au_rw_write_unlock(struct au_rwsem
*rw
)
139 AuRwMustWriteLock(rw
);
141 up_write(&rw
->rwsem
);
144 /* why is not _nested version defined */
145 static inline int au_rw_read_trylock(struct au_rwsem
*rw
)
149 ret
= down_read_trylock(&rw
->rwsem
);
155 static inline int au_rw_write_trylock(struct au_rwsem
*rw
)
159 ret
= down_write_trylock(&rw
->rwsem
);
170 #define AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
171 static inline void prefix##_read_lock(param) \
172 { au_rw_read_lock(rwsem); } \
173 static inline void prefix##_write_lock(param) \
174 { au_rw_write_lock(rwsem); } \
175 static inline int prefix##_read_trylock(param) \
176 { return au_rw_read_trylock(rwsem); } \
177 static inline int prefix##_write_trylock(param) \
178 { return au_rw_write_trylock(rwsem); }
179 /* why is not _nested version defined */
180 /* static inline void prefix##_read_trylock_nested(param, lsc)
181 { au_rw_read_trylock_nested(rwsem, lsc)); }
182 static inline void prefix##_write_trylock_nestd(param, lsc)
183 { au_rw_write_trylock_nested(rwsem, lsc); } */
185 #define AuSimpleUnlockRwsemFuncs(prefix, param, rwsem) \
186 static inline void prefix##_read_unlock(param) \
187 { au_rw_read_unlock(rwsem); } \
188 static inline void prefix##_write_unlock(param) \
189 { au_rw_write_unlock(rwsem); } \
190 static inline void prefix##_downgrade_lock(param) \
191 { au_rw_dgrade_lock(rwsem); }
193 #define AuSimpleRwsemFuncs(prefix, param, rwsem) \
194 AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
195 AuSimpleUnlockRwsemFuncs(prefix, param, rwsem)
197 #endif /* __KERNEL__ */
198 #endif /* __AUFS_RWSEM_H__ */