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 | |
38 | static const char *vgem_fence_get_driver_name(struct dma_fence *fence) |
39 | { |
40 | return "vgem" ; |
41 | } |
42 | |
43 | static const char *vgem_fence_get_timeline_name(struct dma_fence *fence) |
44 | { |
45 | return "unbound" ; |
46 | } |
47 | |
48 | static void vgem_fence_release(struct dma_fence *base) |
49 | { |
50 | struct vgem_fence *fence = container_of(base, typeof(*fence), base); |
51 | |
52 | del_timer_sync(timer: &fence->timer); |
53 | dma_fence_free(fence: &fence->base); |
54 | } |
55 | |
56 | static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size) |
57 | { |
58 | snprintf(buf: str, size, fmt: "%llu" , fence->seqno); |
59 | } |
60 | |
61 | static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str, |
62 | int size) |
63 | { |
64 | snprintf(buf: str, size, fmt: "%llu" , |
65 | dma_fence_is_signaled(fence) ? fence->seqno : 0); |
66 | } |
67 | |
68 | static const struct dma_fence_ops vgem_fence_ops = { |
69 | .get_driver_name = vgem_fence_get_driver_name, |
70 | .get_timeline_name = vgem_fence_get_timeline_name, |
71 | .release = vgem_fence_release, |
72 | |
73 | .fence_value_str = vgem_fence_value_str, |
74 | .timeline_value_str = vgem_fence_timeline_value_str, |
75 | }; |
76 | |
77 | static void vgem_fence_timeout(struct timer_list *t) |
78 | { |
79 | struct vgem_fence *fence = from_timer(fence, t, timer); |
80 | |
81 | dma_fence_signal(fence: &fence->base); |
82 | } |
83 | |
84 | static struct dma_fence *vgem_fence_create(struct vgem_file *vfile, |
85 | unsigned int flags) |
86 | { |
87 | struct vgem_fence *fence; |
88 | |
89 | fence = kzalloc(size: sizeof(*fence), GFP_KERNEL); |
90 | if (!fence) |
91 | return NULL; |
92 | |
93 | spin_lock_init(&fence->lock); |
94 | dma_fence_init(fence: &fence->base, ops: &vgem_fence_ops, lock: &fence->lock, |
95 | context: dma_fence_context_alloc(num: 1), seqno: 1); |
96 | |
97 | timer_setup(&fence->timer, vgem_fence_timeout, 0); |
98 | |
99 | /* We force the fence to expire within 10s to prevent driver hangs */ |
100 | mod_timer(timer: &fence->timer, expires: jiffies + VGEM_FENCE_TIMEOUT); |
101 | |
102 | return &fence->base; |
103 | } |
104 | |
105 | /* |
106 | * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH): |
107 | * |
108 | * Create and attach a fence to the vGEM handle. This fence is then exposed |
109 | * via the dma-buf reservation object and visible to consumers of the exported |
110 | * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the |
111 | * vGEM buffer is being written to by the client and is exposed as an exclusive |
112 | * fence, otherwise the fence indicates the client is current reading from the |
113 | * buffer and all future writes should wait for the client to signal its |
114 | * completion. Note that if a conflicting fence is already on the dma-buf (i.e. |
115 | * an exclusive fence when adding a read, or any fence when adding a write), |
116 | * -EBUSY is reported. Serialisation between operations should be handled |
117 | * by waiting upon the dma-buf. |
118 | * |
119 | * This returns the handle for the new fence that must be signaled within 10 |
120 | * seconds (or otherwise it will automatically expire). See |
121 | * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL). |
122 | * |
123 | * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT. |
124 | */ |
125 | int vgem_fence_attach_ioctl(struct drm_device *dev, |
126 | void *data, |
127 | struct drm_file *file) |
128 | { |
129 | struct drm_vgem_fence_attach *arg = data; |
130 | struct vgem_file *vfile = file->driver_priv; |
131 | struct dma_resv *resv; |
132 | struct drm_gem_object *obj; |
133 | enum dma_resv_usage usage; |
134 | struct dma_fence *fence; |
135 | int ret; |
136 | |
137 | if (arg->flags & ~VGEM_FENCE_WRITE) |
138 | return -EINVAL; |
139 | |
140 | if (arg->pad) |
141 | return -EINVAL; |
142 | |
143 | obj = drm_gem_object_lookup(filp: file, handle: arg->handle); |
144 | if (!obj) |
145 | return -ENOENT; |
146 | |
147 | fence = vgem_fence_create(vfile, flags: arg->flags); |
148 | if (!fence) { |
149 | ret = -ENOMEM; |
150 | goto err; |
151 | } |
152 | |
153 | /* Check for a conflicting fence */ |
154 | resv = obj->resv; |
155 | usage = dma_resv_usage_rw(write: arg->flags & VGEM_FENCE_WRITE); |
156 | if (!dma_resv_test_signaled(obj: resv, usage)) { |
157 | ret = -EBUSY; |
158 | goto err_fence; |
159 | } |
160 | |
161 | /* Expose the fence via the dma-buf */ |
162 | dma_resv_lock(obj: resv, NULL); |
163 | ret = dma_resv_reserve_fences(obj: resv, num_fences: 1); |
164 | if (!ret) |
165 | dma_resv_add_fence(obj: resv, fence, usage: arg->flags & VGEM_FENCE_WRITE ? |
166 | DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ); |
167 | dma_resv_unlock(obj: resv); |
168 | |
169 | /* Record the fence in our idr for later signaling */ |
170 | if (ret == 0) { |
171 | mutex_lock(&vfile->fence_mutex); |
172 | ret = idr_alloc(&vfile->fence_idr, ptr: fence, start: 1, end: 0, GFP_KERNEL); |
173 | mutex_unlock(lock: &vfile->fence_mutex); |
174 | if (ret > 0) { |
175 | arg->out_fence = ret; |
176 | ret = 0; |
177 | } |
178 | } |
179 | err_fence: |
180 | if (ret) { |
181 | dma_fence_signal(fence); |
182 | dma_fence_put(fence); |
183 | } |
184 | err: |
185 | drm_gem_object_put(obj); |
186 | return ret; |
187 | } |
188 | |
189 | /* |
190 | * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL): |
191 | * |
192 | * Signal and consume a fence ealier attached to a vGEM handle using |
193 | * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH). |
194 | * |
195 | * All fences must be signaled within 10s of attachment or otherwise they |
196 | * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT). |
197 | * |
198 | * Signaling a fence indicates to all consumers of the dma-buf that the |
199 | * client has completed the operation associated with the fence, and that the |
200 | * buffer is then ready for consumption. |
201 | * |
202 | * If the fence does not exist (or has already been signaled by the client), |
203 | * vgem_fence_signal_ioctl returns -ENOENT. |
204 | */ |
205 | int vgem_fence_signal_ioctl(struct drm_device *dev, |
206 | void *data, |
207 | struct drm_file *file) |
208 | { |
209 | struct vgem_file *vfile = file->driver_priv; |
210 | struct drm_vgem_fence_signal *arg = data; |
211 | struct dma_fence *fence; |
212 | int ret = 0; |
213 | |
214 | if (arg->flags) |
215 | return -EINVAL; |
216 | |
217 | mutex_lock(&vfile->fence_mutex); |
218 | fence = idr_replace(&vfile->fence_idr, NULL, id: arg->fence); |
219 | mutex_unlock(lock: &vfile->fence_mutex); |
220 | if (!fence) |
221 | return -ENOENT; |
222 | if (IS_ERR(ptr: fence)) |
223 | return PTR_ERR(ptr: fence); |
224 | |
225 | if (dma_fence_is_signaled(fence)) |
226 | ret = -ETIMEDOUT; |
227 | |
228 | dma_fence_signal(fence); |
229 | dma_fence_put(fence); |
230 | return ret; |
231 | } |
232 | |
233 | int vgem_fence_open(struct vgem_file *vfile) |
234 | { |
235 | mutex_init(&vfile->fence_mutex); |
236 | idr_init_base(idr: &vfile->fence_idr, base: 1); |
237 | |
238 | return 0; |
239 | } |
240 | |
241 | static int __vgem_fence_idr_fini(int id, void *p, void *data) |
242 | { |
243 | dma_fence_signal(fence: p); |
244 | dma_fence_put(fence: p); |
245 | return 0; |
246 | } |
247 | |
248 | void vgem_fence_close(struct vgem_file *vfile) |
249 | { |
250 | idr_for_each(&vfile->fence_idr, fn: __vgem_fence_idr_fini, data: vfile); |
251 | idr_destroy(&vfile->fence_idr); |
252 | mutex_destroy(lock: &vfile->fence_mutex); |
253 | } |
254 | |