include/linux/reservation.h

   1 /*
   2  * Header file for reservations for dma-buf and ttm
   3  *
   4  * Copyright(C) 2011 Linaro Limited. All rights reserved.
   5  * Copyright (C) 2012-2013 Canonical Ltd
   6  * Copyright (C) 2012 Texas Instruments
   7  *
   8  * Authors:
   9  * Rob Clark <robdclark@gmail.com>
  10  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
  11  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  12  *
  13  * Based on bo.c which bears the following copyright notice,
  14  * but is dual licensed:
  15  *
  16  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
  17  * All Rights Reserved.
  18  *
  19  * Permission is hereby granted, free of charge, to any person obtaining a
  20  * copy of this software and associated documentation files (the
  21  * "Software"), to deal in the Software without restriction, including
  22  * without limitation the rights to use, copy, modify, merge, publish,
  23  * distribute, sub license, and/or sell copies of the Software, and to
  24  * permit persons to whom the Software is furnished to do so, subject to
  25  * the following conditions:
  26  *
  27  * The above copyright notice and this permission notice (including the
  28  * next paragraph) shall be included in all copies or substantial portions
  29  * of the Software.
  30  *
  31  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  32  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  33  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  34  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  35  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  36  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  37  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  38  */
  39 #ifndef _LINUX_RESERVATION_H
  40 #define _LINUX_RESERVATION_H
  41
  42 #include <linux/ww_mutex.h>
  43 #include <linux/fence.h>
  44 #include <linux/slab.h>
  45 #include <linux/seqlock.h>
  46 #include <linux/rcupdate.h>
  47
  48 extern struct ww_class reservation_ww_class;
  49 extern struct lock_class_key reservation_seqcount_class;
  50 extern const char reservation_seqcount_string[];
  51
  52 struct reservation_object_list {
  53         struct rcu_head rcu;
  54         u32 shared_count, shared_max;
  55         struct fence __rcu *shared[];
  56 };
  57
  58 struct reservation_object {
  59         struct ww_mutex lock;
  60         seqcount_t seq;
  61
  62         struct fence __rcu *fence_excl;
  63         struct reservation_object_list __rcu *fence;
  64         struct reservation_object_list *staged;
  65 };
  66
  67 #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
  68 #define reservation_object_assert_held(obj) \
  69         lockdep_assert_held(&(obj)->lock.base)
  70
  71 static inline void
  72 reservation_object_init(struct reservation_object *obj)
  73 {
  74         ww_mutex_init(&obj->lock, &reservation_ww_class);
  75
  76         __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
  77         RCU_INIT_POINTER(obj->fence, NULL);
  78         RCU_INIT_POINTER(obj->fence_excl, NULL);
  79         obj->staged = NULL;
  80 }
  81
  82 static inline void
  83 reservation_object_fini(struct reservation_object *obj)
  84 {
  85         int i;
  86         struct reservation_object_list *fobj;
  87         struct fence *excl;
  88
  89         /*
  90          * This object should be dead and all references must have
  91          * been released to it, so no need to be protected with rcu.
  92          */
  93         excl = rcu_dereference_protected(obj->fence_excl, 1);
  94         if (excl)
  95                 fence_put(excl);
  96
  97         fobj = rcu_dereference_protected(obj->fence, 1);
  98         if (fobj) {
  99                 for (i = 0; i < fobj->shared_count; ++i)
 100                         fence_put(rcu_dereference_protected(fobj->shared[i], 1));
 101
 102                 kfree(fobj);
 103         }
 104         kfree(obj->staged);
 105
 106         ww_mutex_destroy(&obj->lock);
 107 }
 108
 109 static inline struct reservation_object_list *
 110 reservation_object_get_list(struct reservation_object *obj)
 111 {
 112         return rcu_dereference_protected(obj->fence,
 113                                          reservation_object_held(obj));
 114 }
 115
 116 static inline struct fence *
 117 reservation_object_get_excl(struct reservation_object *obj)
 118 {
 119         return rcu_dereference_protected(obj->fence_excl,
 120                                          reservation_object_held(obj));
 121 }
 122
 123 int reservation_object_reserve_shared(struct reservation_object *obj);
 124 void reservation_object_add_shared_fence(struct reservation_object *obj,
 125                                          struct fence *fence);
 126
 127 void reservation_object_add_excl_fence(struct reservation_object *obj,
 128                                        struct fence *fence);
 129
 130 int reservation_object_get_fences_rcu(struct reservation_object *obj,
 131                                       struct fence **pfence_excl,
 132                                       unsigned *pshared_count,
 133                                       struct fence ***pshared);
 134
 135 long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
 136                                          bool wait_all, bool intr,
 137                                          unsigned long timeout);
 138
 139 bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
 140                                           bool test_all);
 141
 142 #endif /* _LINUX_RESERVATION_H */