fs/aufs/rwsem.h

   1 /*
   2  * Copyright (C) 2005-2017 Junjiro R. Okajima
   3  *
   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.
   8  *
   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.
  13  *
  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/>.
  16  */
  17
  18 /*
  19  * simple read-write semaphore wrappers
  20  */
  21
  22 #ifndef __AUFS_RWSEM_H__
  23 #define __AUFS_RWSEM_H__
  24
  25 #ifdef __KERNEL__
  26
  27 #include "debug.h"
  28
  29 /* in the futre, the name 'au_rwsem' will be totally gone */
  30 #define au_rwsem        rw_semaphore
  31
  32 /* to debug easier, do not make them inlined functions */
  33 #define AuRwMustNoWaiters(rw)   AuDebugOn(rwsem_is_contended(rw))
  34 /* rwsem_is_locked() is unusable */
  35 #define AuRwMustReadLock(rw)    AuDebugOn(!lockdep_recursing(current) \
  36                                           && debug_locks \
  37                                           && !lockdep_is_held_type(rw, 1))
  38 #define AuRwMustWriteLock(rw)   AuDebugOn(!lockdep_recursing(current) \
  39                                           && debug_locks \
  40                                           && !lockdep_is_held_type(rw, 0))
  41 #define AuRwMustAnyLock(rw)     AuDebugOn(!lockdep_recursing(current) \
  42                                           && debug_locks \
  43                                           && !lockdep_is_held(rw))
  44 #define AuRwDestroy(rw)         AuDebugOn(!lockdep_recursing(current) \
  45                                           && debug_locks \
  46                                           && lockdep_is_held(rw))
  47
  48 #define au_rw_init(rw)  init_rwsem(rw)
  49
  50 #define au_rw_init_wlock(rw) do {               \
  51                 au_rw_init(rw);                 \
  52                 down_write(rw);                 \
  53         } while (0)
  54
  55 #define au_rw_init_wlock_nested(rw, lsc) do {   \
  56                 au_rw_init(rw);                 \
  57                 down_write_nested(rw, lsc);     \
  58         } while (0)
  59
  60 #define au_rw_read_lock(rw)             down_read(rw)
  61 #define au_rw_read_lock_nested(rw, lsc) down_read_nested(rw, lsc)
  62 #define au_rw_read_unlock(rw)           up_read(rw)
  63 #define au_rw_dgrade_lock(rw)           downgrade_write(rw)
  64 #define au_rw_write_lock(rw)            down_write(rw)
  65 #define au_rw_write_lock_nested(rw, lsc) down_write_nested(rw, lsc)
  66 #define au_rw_write_unlock(rw)          up_write(rw)
  67 /* why is not _nested version defined? */
  68 #define au_rw_read_trylock(rw)          down_read_trylock(rw)
  69 #define au_rw_write_trylock(rw)         down_write_trylock(rw)
  70
  71 #endif /* __KERNEL__ */
  72 #endif /* __AUFS_RWSEM_H__ */