1 /*
2  * Copyright © 2017 Intel Corporation
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21  * IN THE SOFTWARE.
22  *
23  */
24 
25 #include "lib_sw_fence.h"
26 
27 /* Small library of different fence types useful for writing tests */
28 
29 static int
30 nop_fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
31 {
32 	return NOTIFY_DONE;
33 }
34 
35 void __onstack_fence_init(struct i915_sw_fence *fence,
36 			  const char *name,
37 			  struct lock_class_key *key)
38 {
39 	debug_fence_init_onstack(fence);
40 
41 	__init_waitqueue_head(&fence->wait, name, key);
42 	atomic_set(&fence->pending, 1);
43 	fence->error = 0;
44 	fence->fn = nop_fence_notify;
45 }
46 
47 void onstack_fence_fini(struct i915_sw_fence *fence)
48 {
49 	if (!fence->fn)
50 		return;
51 
52 	i915_sw_fence_commit(fence);
53 	i915_sw_fence_fini(fence);
54 }
55 
56 static void timed_fence_wake(struct timer_list *t)
57 {
58 	struct timed_fence *tf = from_timer(tf, t, timer);
59 
60 	i915_sw_fence_commit(&tf->fence);
61 }
62 
63 void timed_fence_init(struct timed_fence *tf, unsigned long expires)
64 {
65 	onstack_fence_init(&tf->fence);
66 
67 	timer_setup_on_stack(&tf->timer, timed_fence_wake, 0);
68 
69 	if (time_after(expires, jiffies))
70 		mod_timer(&tf->timer, expires);
71 	else
72 		i915_sw_fence_commit(&tf->fence);
73 }
74 
75 void timed_fence_fini(struct timed_fence *tf)
76 {
77 	if (del_timer_sync(&tf->timer))
78 		i915_sw_fence_commit(&tf->fence);
79 
80 	destroy_timer_on_stack(&tf->timer);
81 	i915_sw_fence_fini(&tf->fence);
82 }
83 
84 struct heap_fence {
85 	struct i915_sw_fence fence;
86 	union {
87 		struct kref ref;
88 		struct rcu_head rcu;
89 	};
90 };
91 
92 static int
93 heap_fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
94 {
95 	struct heap_fence *h = container_of(fence, typeof(*h), fence);
96 
97 	switch (state) {
98 	case FENCE_COMPLETE:
99 		break;
100 
101 	case FENCE_FREE:
102 		heap_fence_put(&h->fence);
103 	}
104 
105 	return NOTIFY_DONE;
106 }
107 
108 struct i915_sw_fence *heap_fence_create(gfp_t gfp)
109 {
110 	struct heap_fence *h;
111 
112 	h = kmalloc(sizeof(*h), gfp);
113 	if (!h)
114 		return NULL;
115 
116 	i915_sw_fence_init(&h->fence, heap_fence_notify);
117 	refcount_set(&h->ref.refcount, 2);
118 
119 	return &h->fence;
120 }
121 
122 static void heap_fence_release(struct kref *ref)
123 {
124 	struct heap_fence *h = container_of(ref, typeof(*h), ref);
125 
126 	i915_sw_fence_fini(&h->fence);
127 
128 	kfree_rcu(h, rcu);
129 }
130 
131 void heap_fence_put(struct i915_sw_fence *fence)
132 {
133 	struct heap_fence *h = container_of(fence, typeof(*h), fence);
134 
135 	kref_put(&h->ref, heap_fence_release);
136 }
137