include/sys/rwlock.h

   1 /*
   2  *  This file is part of the SPL: Solaris Porting Layer.
   3  *
   4  *  Copyright (c) 2008 Lawrence Livermore National Security, LLC.
   5  *  Produced at Lawrence Livermore National Laboratory
   6  *  Written by:
   7  *          Brian Behlendorf <behlendorf1@llnl.gov>,
   8  *          Herb Wartens <wartens2@llnl.gov>,
   9  *          Jim Garlick <garlick@llnl.gov>
  10  *  UCRL-CODE-235197
  11  *
  12  *  This is free software; you can redistribute it and/or modify it
  13  *  under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or
  15  *  (at your option) any later version.
  16  *
  17  *  This is distributed in the hope that it will be useful, but WITHOUT
  18  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  *  for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License along
  23  *  with this program; if not, write to the Free Software Foundation, Inc.,
  24  *  51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  25  */
  26
  27 #ifndef _SPL_RWLOCK_H
  28 #define _SPL_RWLOCK_H
  29
  30 #include <linux/module.h>
  31 #include <linux/slab.h>
  32 #include <linux/rwsem.h>
  33 #include <asm/current.h>
  34 #include <sys/types.h>
  35 #include <sys/kmem.h>
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 typedef enum {
  42         RW_DRIVER  = 2,         /* driver (DDI) rwlock */
  43         RW_DEFAULT = 4          /* kernel default rwlock */
  44 } krw_type_t;
  45
  46 typedef enum {
  47         RW_WRITER,
  48         RW_READER
  49 } krw_t;
  50
  51
  52 #define RW_MAGIC  0x3423645a
  53 #define RW_POISON 0xa6
  54
  55 typedef struct {
  56         int32_t rw_magic;
  57         int32_t rw_name_size;
  58         char *rw_name;
  59         struct rw_semaphore rw_sem;
  60         struct task_struct *rw_owner;   /* holder of the write lock */
  61 } krwlock_t;
  62
  63 extern void __rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg);
  64 extern void __rw_destroy(krwlock_t *rwlp);
  65 extern int __rw_tryenter(krwlock_t *rwlp, krw_t rw);
  66 extern void __rw_enter(krwlock_t *rwlp, krw_t rw);
  67 extern void __rw_exit(krwlock_t *rwlp);
  68 extern void __rw_downgrade(krwlock_t *rwlp);
  69 extern int __rw_tryupgrade(krwlock_t *rwlp);
  70 extern kthread_t *__rw_owner(krwlock_t *rwlp);
  71 extern int __rw_read_held(krwlock_t *rwlp);
  72 extern int __rw_write_held(krwlock_t *rwlp);
  73 extern int __rw_lock_held(krwlock_t *rwlp);
  74
  75 #define rw_init(rwlp, name, type, arg)                                  \
  76 ({                                                                      \
  77         if ((name) == NULL)                                             \
  78                 __rw_init(rwlp, #rwlp, type, arg);                      \
  79         else                                                            \
  80                 __rw_init(rwlp, name, type, arg);                       \
  81 })
  82 #define rw_destroy(rwlp)        __rw_destroy(rwlp)
  83 #define rw_tryenter(rwlp, rw)   __rw_tryenter(rwlp, rw)
  84 #define rw_enter(rwlp, rw)      __rw_enter(rwlp, rw)
  85 #define rw_exit(rwlp)           __rw_exit(rwlp)
  86 #define rw_downgrade(rwlp)      __rw_downgrade(rwlp)
  87 #define rw_tryupgrade(rwlp)     __rw_tryupgrade(rwlp)
  88 #define rw_owner(rwlp)          __rw_owner(rwlp)
  89 #define RW_READ_HELD(rwlp)      __rw_read_held(rwlp)
  90 #define RW_WRITE_HELD(rwlp)     __rw_write_held(rwlp)
  91 #define RW_LOCK_HELD(rwlp)      __rw_lock_held(rwlp)
  92
  93 #ifdef __cplusplus
  94 }
  95 #endif
  96
  97 #endif /* _SPL_RWLOCK_H */