sys/compat/linuxkpi/common/include/linux/ww_mutex.h

   1 /*-
   2  * Copyright (c) 2017 Mellanox Technologies, Ltd.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28 #ifndef _LINUX_WW_MUTEX_H_
  29 #define _LINUX_WW_MUTEX_H_
  30
  31 #include <sys/param.h>
  32 #include <sys/proc.h>
  33 #include <sys/condvar.h>
  34 #include <sys/kernel.h>
  35
  36 #include <linux/mutex.h>
  37
  38 struct ww_class {
  39         const char *mutex_name;
  40 };
  41
  42 struct ww_acquire_ctx {
  43 };
  44
  45 struct ww_mutex {
  46         struct mutex base;
  47         struct cv condvar;
  48 };
  49
  50 #define DEFINE_WW_CLASS(name)                                   \
  51         struct ww_class name = {                                \
  52                 .mutex_name = mutex_name(#name "_mutex")        \
  53         }
  54
  55 #define DEFINE_WW_MUTEX(name, ww_class)                                 \
  56         struct ww_mutex name;                                           \
  57         static void name##_init(void *arg)                              \
  58         {                                                               \
  59                 ww_mutex_init(&name, &ww_class);                        \
  60         }                                                               \
  61         SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_init, NULL)
  62
  63 #define ww_mutex_is_locked(_m) \
  64         sx_xlocked(&(_m)->base.sx)
  65
  66 #define ww_mutex_lock_slow(_m, _x) \
  67         ww_mutex_lock(_m, _x)
  68
  69 #define ww_mutex_lock_slow_interruptible(_m, _x) \
  70         ww_mutex_lock_interruptible(_m, _x)
  71
  72 static inline int __must_check
  73 ww_mutex_trylock(struct ww_mutex *lock)
  74 {
  75         return (mutex_trylock(&lock->base));
  76 }
  77
  78 extern int linux_ww_mutex_lock_sub(struct ww_mutex *, int catch_signal);
  79
  80 static inline int
  81 ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
  82 {
  83         if (MUTEX_SKIP())
  84                 return (0);
  85         else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
  86                 return (-EALREADY);
  87         else
  88                 return (linux_ww_mutex_lock_sub(lock, 0));
  89 }
  90
  91 static inline int
  92 ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
  93 {
  94         if (MUTEX_SKIP())
  95                 return (0);
  96         else if ((struct thread *)SX_OWNER(lock->base.sx.sx_lock) == curthread)
  97                 return (-EALREADY);
  98         else
  99                 return (linux_ww_mutex_lock_sub(lock, 1));
 100 }
 101
 102 extern void linux_ww_mutex_unlock_sub(struct ww_mutex *);
 103
 104 static inline void
 105 ww_mutex_unlock(struct ww_mutex *lock)
 106 {
 107         if (MUTEX_SKIP())
 108                 return;
 109         else
 110                 linux_ww_mutex_unlock_sub(lock);
 111 }
 112
 113 static inline void
 114 ww_mutex_destroy(struct ww_mutex *lock)
 115 {
 116         cv_destroy(&lock->condvar);
 117         mutex_destroy(&lock->base);
 118 }
 119
 120 static inline void
 121 ww_acquire_init(struct ww_acquire_ctx *ctx, struct ww_class *ww_class)
 122 {
 123 }
 124
 125 static inline void
 126 ww_mutex_init(struct ww_mutex *lock, struct ww_class *ww_class)
 127 {
 128         linux_mutex_init(&lock->base, ww_class->mutex_name, SX_NOWITNESS);
 129         cv_init(&lock->condvar, "lkpi-ww");
 130 }
 131
 132 static inline void
 133 ww_acquire_fini(struct ww_acquire_ctx *ctx)
 134 {
 135 }
 136
 137 static inline void
 138 ww_acquire_done(struct ww_acquire_ctx *ctx)
 139 {
 140 }
 141
 142 #endif                                  /* _LINUX_WW_MUTEX_H_ */