1 /*
2 * Copyright 2016 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 * on the rights to use, copy, modify, merge, publish, distribute, sub
8 * license, and/or sell copies of the Software, and to permit persons to whom
9 * them 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 MERCHANTIBILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
19 * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 */
22
23 #include <linux/dma-buf.h>
24 #include <linux/dma-resv.h>
25
26 #include <drm/drm_file.h>
27
28 #include "vgem_drv.h"
29
30 #define VGEM_FENCE_TIMEOUT (10*HZ)
31
32 struct vgem_fence {
33 struct dma_fence base;
34 struct spinlock lock;
35 struct timer_list timer;
36 };
37
vgem_fence_get_driver_name(struct dma_fence * fence)38 static const char *vgem_fence_get_driver_name(struct dma_fence *fence)
39 {
40 return "vgem";
41 }
42
vgem_fence_get_timeline_name(struct dma_fence * fence)43 static const char *vgem_fence_get_timeline_name(struct dma_fence *fence)
44 {
45 return "unbound";
46 }
47
vgem_fence_release(struct dma_fence * base)48 static void vgem_fence_release(struct dma_fence *base)
49 {
50 struct vgem_fence *fence = container_of(base, typeof(*fence), base);
51
52 timer_delete_sync(&fence->timer);
53 dma_fence_free(&fence->base);
54 }
55
56 static const struct dma_fence_ops vgem_fence_ops = {
57 .get_driver_name = vgem_fence_get_driver_name,
58 .get_timeline_name = vgem_fence_get_timeline_name,
59 .release = vgem_fence_release,
60 };
61
vgem_fence_timeout(struct timer_list * t)62 static void vgem_fence_timeout(struct timer_list *t)
63 {
64 struct vgem_fence *fence = timer_container_of(fence, t, timer);
65
66 dma_fence_signal(&fence->base);
67 }
68
vgem_fence_create(struct vgem_file * vfile,unsigned int flags)69 static struct dma_fence *vgem_fence_create(struct vgem_file *vfile,
70 unsigned int flags)
71 {
72 struct vgem_fence *fence;
73
74 fence = kzalloc(sizeof(*fence), GFP_KERNEL);
75 if (!fence)
76 return NULL;
77
78 spin_lock_init(&fence->lock);
79 dma_fence_init(&fence->base, &vgem_fence_ops, &fence->lock,
80 dma_fence_context_alloc(1), 1);
81
82 timer_setup(&fence->timer, vgem_fence_timeout, 0);
83
84 /* We force the fence to expire within 10s to prevent driver hangs */
85 mod_timer(&fence->timer, jiffies + VGEM_FENCE_TIMEOUT);
86
87 return &fence->base;
88 }
89
90 /*
91 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH):
92 *
93 * Create and attach a fence to the vGEM handle. This fence is then exposed
94 * via the dma-buf reservation object and visible to consumers of the exported
95 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the
96 * vGEM buffer is being written to by the client and is exposed as an exclusive
97 * fence, otherwise the fence indicates the client is current reading from the
98 * buffer and all future writes should wait for the client to signal its
99 * completion. Note that if a conflicting fence is already on the dma-buf (i.e.
100 * an exclusive fence when adding a read, or any fence when adding a write),
101 * -EBUSY is reported. Serialisation between operations should be handled
102 * by waiting upon the dma-buf.
103 *
104 * This returns the handle for the new fence that must be signaled within 10
105 * seconds (or otherwise it will automatically expire). See
106 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL).
107 *
108 * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT.
109 */
vgem_fence_attach_ioctl(struct drm_device * dev,void * data,struct drm_file * file)110 int vgem_fence_attach_ioctl(struct drm_device *dev,
111 void *data,
112 struct drm_file *file)
113 {
114 struct drm_vgem_fence_attach *arg = data;
115 struct vgem_file *vfile = file->driver_priv;
116 struct dma_resv *resv;
117 struct drm_gem_object *obj;
118 enum dma_resv_usage usage;
119 struct dma_fence *fence;
120 int ret;
121
122 if (arg->flags & ~VGEM_FENCE_WRITE)
123 return -EINVAL;
124
125 if (arg->pad)
126 return -EINVAL;
127
128 obj = drm_gem_object_lookup(file, arg->handle);
129 if (!obj)
130 return -ENOENT;
131
132 fence = vgem_fence_create(vfile, arg->flags);
133 if (!fence) {
134 ret = -ENOMEM;
135 goto err;
136 }
137
138 /* Check for a conflicting fence */
139 resv = obj->resv;
140 usage = dma_resv_usage_rw(arg->flags & VGEM_FENCE_WRITE);
141 if (!dma_resv_test_signaled(resv, usage)) {
142 ret = -EBUSY;
143 goto err_fence;
144 }
145
146 /* Expose the fence via the dma-buf */
147 dma_resv_lock(resv, NULL);
148 ret = dma_resv_reserve_fences(resv, 1);
149 if (!ret)
150 dma_resv_add_fence(resv, fence, arg->flags & VGEM_FENCE_WRITE ?
151 DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
152 dma_resv_unlock(resv);
153
154 /* Record the fence in our idr for later signaling */
155 if (ret == 0) {
156 mutex_lock(&vfile->fence_mutex);
157 ret = idr_alloc(&vfile->fence_idr, fence, 1, 0, GFP_KERNEL);
158 mutex_unlock(&vfile->fence_mutex);
159 if (ret > 0) {
160 arg->out_fence = ret;
161 ret = 0;
162 }
163 }
164 err_fence:
165 if (ret) {
166 dma_fence_signal(fence);
167 dma_fence_put(fence);
168 }
169 err:
170 drm_gem_object_put(obj);
171 return ret;
172 }
173
174 /*
175 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL):
176 *
177 * Signal and consume a fence ealier attached to a vGEM handle using
178 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH).
179 *
180 * All fences must be signaled within 10s of attachment or otherwise they
181 * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT).
182 *
183 * Signaling a fence indicates to all consumers of the dma-buf that the
184 * client has completed the operation associated with the fence, and that the
185 * buffer is then ready for consumption.
186 *
187 * If the fence does not exist (or has already been signaled by the client),
188 * vgem_fence_signal_ioctl returns -ENOENT.
189 */
vgem_fence_signal_ioctl(struct drm_device * dev,void * data,struct drm_file * file)190 int vgem_fence_signal_ioctl(struct drm_device *dev,
191 void *data,
192 struct drm_file *file)
193 {
194 struct vgem_file *vfile = file->driver_priv;
195 struct drm_vgem_fence_signal *arg = data;
196 struct dma_fence *fence;
197 int ret = 0;
198
199 if (arg->flags)
200 return -EINVAL;
201
202 mutex_lock(&vfile->fence_mutex);
203 fence = idr_replace(&vfile->fence_idr, NULL, arg->fence);
204 mutex_unlock(&vfile->fence_mutex);
205 if (!fence)
206 return -ENOENT;
207 if (IS_ERR(fence))
208 return PTR_ERR(fence);
209
210 if (dma_fence_is_signaled(fence))
211 ret = -ETIMEDOUT;
212
213 dma_fence_signal(fence);
214 dma_fence_put(fence);
215 return ret;
216 }
217
vgem_fence_open(struct vgem_file * vfile)218 int vgem_fence_open(struct vgem_file *vfile)
219 {
220 mutex_init(&vfile->fence_mutex);
221 idr_init_base(&vfile->fence_idr, 1);
222
223 return 0;
224 }
225
__vgem_fence_idr_fini(int id,void * p,void * data)226 static int __vgem_fence_idr_fini(int id, void *p, void *data)
227 {
228 dma_fence_signal(p);
229 dma_fence_put(p);
230 return 0;
231 }
232
vgem_fence_close(struct vgem_file * vfile)233 void vgem_fence_close(struct vgem_file *vfile)
234 {
235 idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile);
236 idr_destroy(&vfile->fence_idr);
237 mutex_destroy(&vfile->fence_mutex);
238 }
239