summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/vgem/vgem_fence.c
blob: 9268f6fc3f6622a71e435a143e2d0b6c199b6887 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/*
 * Copyright 2016 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software")
 * to deal in the software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * them Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <linux/dma-buf.h>
#include <linux/dma-resv.h>

#include <drm/drm_file.h>

#include "vgem_drv.h"

#define VGEM_FENCE_TIMEOUT (10*HZ)

struct vgem_fence {
	struct dma_fence base;
	struct spinlock lock;
	struct timer_list timer;
};

static const char *vgem_fence_get_driver_name(struct dma_fence *fence)
{
	return "vgem";
}

static const char *vgem_fence_get_timeline_name(struct dma_fence *fence)
{
	return "unbound";
}

static void vgem_fence_release(struct dma_fence *base)
{
	struct vgem_fence *fence = container_of(base, typeof(*fence), base);

	del_timer_sync(&fence->timer);
	dma_fence_free(&fence->base);
}

static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size)
{
	snprintf(str, size, "%llu", fence->seqno);
}

static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str,
					  int size)
{
	snprintf(str, size, "%llu",
		 dma_fence_is_signaled(fence) ? fence->seqno : 0);
}

static const struct dma_fence_ops vgem_fence_ops = {
	.get_driver_name = vgem_fence_get_driver_name,
	.get_timeline_name = vgem_fence_get_timeline_name,
	.release = vgem_fence_release,

	.fence_value_str = vgem_fence_value_str,
	.timeline_value_str = vgem_fence_timeline_value_str,
};

static void vgem_fence_timeout(struct timer_list *t)
{
	struct vgem_fence *fence = from_timer(fence, t, timer);

	dma_fence_signal(&fence->base);
}

static struct dma_fence *vgem_fence_create(struct vgem_file *vfile,
					   unsigned int flags)
{
	struct vgem_fence *fence;

	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
	if (!fence)
		return NULL;

	spin_lock_init(&fence->lock);
	dma_fence_init(&fence->base, &vgem_fence_ops, &fence->lock,
		       dma_fence_context_alloc(1), 1);

	timer_setup(&fence->timer, vgem_fence_timeout, 0);

	/* We force the fence to expire within 10s to prevent driver hangs */
	mod_timer(&fence->timer, jiffies + VGEM_FENCE_TIMEOUT);

	return &fence->base;
}

/*
 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH):
 *
 * Create and attach a fence to the vGEM handle. This fence is then exposed
 * via the dma-buf reservation object and visible to consumers of the exported
 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the
 * vGEM buffer is being written to by the client and is exposed as an exclusive
 * fence, otherwise the fence indicates the client is current reading from the
 * buffer and all future writes should wait for the client to signal its
 * completion. Note that if a conflicting fence is already on the dma-buf (i.e.
 * an exclusive fence when adding a read, or any fence when adding a write),
 * -EBUSY is reported. Serialisation between operations should be handled
 * by waiting upon the dma-buf.
 *
 * This returns the handle for the new fence that must be signaled within 10
 * seconds (or otherwise it will automatically expire). See
 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL).
 *
 * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT.
 */
int vgem_fence_attach_ioctl(struct drm_device *dev,
			    void *data,
			    struct drm_file *file)
{
	struct drm_vgem_fence_attach *arg = data;
	struct vgem_file *vfile = file->driver_priv;
	struct dma_resv *resv;
	struct drm_gem_object *obj;
	struct dma_fence *fence;
	int ret;

	if (arg->flags & ~VGEM_FENCE_WRITE)
		return -EINVAL;

	if (arg->pad)
		return -EINVAL;

	obj = drm_gem_object_lookup(file, arg->handle);
	if (!obj)
		return -ENOENT;

	fence = vgem_fence_create(vfile, arg->flags);
	if (!fence) {
		ret = -ENOMEM;
		goto err;
	}

	/* Check for a conflicting fence */
	resv = obj->resv;
	if (!dma_resv_test_signaled_rcu(resv,
						  arg->flags & VGEM_FENCE_WRITE)) {
		ret = -EBUSY;
		goto err_fence;
	}

	/* Expose the fence via the dma-buf */
	ret = 0;
	dma_resv_lock(resv, NULL);
	if (arg->flags & VGEM_FENCE_WRITE)
		dma_resv_add_excl_fence(resv, fence);
	else if ((ret = dma_resv_reserve_shared(resv, 1)) == 0)
		dma_resv_add_shared_fence(resv, fence);
	dma_resv_unlock(resv);

	/* Record the fence in our idr for later signaling */
	if (ret == 0) {
		mutex_lock(&vfile->fence_mutex);
		ret = idr_alloc(&vfile->fence_idr, fence, 1, 0, GFP_KERNEL);
		mutex_unlock(&vfile->fence_mutex);
		if (ret > 0) {
			arg->out_fence = ret;
			ret = 0;
		}
	}
err_fence:
	if (ret) {
		dma_fence_signal(fence);
		dma_fence_put(fence);
	}
err:
	drm_gem_object_put_unlocked(obj);
	return ret;
}

/*
 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL):
 *
 * Signal and consume a fence ealier attached to a vGEM handle using
 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH).
 *
 * All fences must be signaled within 10s of attachment or otherwise they
 * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT).
 *
 * Signaling a fence indicates to all consumers of the dma-buf that the
 * client has completed the operation associated with the fence, and that the
 * buffer is then ready for consumption.
 *
 * If the fence does not exist (or has already been signaled by the client),
 * vgem_fence_signal_ioctl returns -ENOENT.
 */
int vgem_fence_signal_ioctl(struct drm_device *dev,
			    void *data,
			    struct drm_file *file)
{
	struct vgem_file *vfile = file->driver_priv;
	struct drm_vgem_fence_signal *arg = data;
	struct dma_fence *fence;
	int ret = 0;

	if (arg->flags)
		return -EINVAL;

	mutex_lock(&vfile->fence_mutex);
	fence = idr_replace(&vfile->fence_idr, NULL, arg->fence);
	mutex_unlock(&vfile->fence_mutex);
	if (!fence)
		return -ENOENT;
	if (IS_ERR(fence))
		return PTR_ERR(fence);

	if (dma_fence_is_signaled(fence))
		ret = -ETIMEDOUT;

	dma_fence_signal(fence);
	dma_fence_put(fence);
	return ret;
}

int vgem_fence_open(struct vgem_file *vfile)
{
	mutex_init(&vfile->fence_mutex);
	idr_init(&vfile->fence_idr);

	return 0;
}

static int __vgem_fence_idr_fini(int id, void *p, void *data)
{
	dma_fence_signal(p);
	dma_fence_put(p);
	return 0;
}

void vgem_fence_close(struct vgem_file *vfile)
{
	idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile);
	idr_destroy(&vfile->fence_idr);
}