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1 | /* |
2 | * Copyright © 2012 Red Hat | |
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 | * Authors: | |
24 | * Dave Airlie <airlied@redhat.com> | |
25 | * Rob Clark <rob.clark@linaro.org> | |
26 | * | |
27 | */ | |
28 | ||
29 | #include <linux/export.h> | |
30 | #include <linux/dma-buf.h> | |
31 | #include "drmP.h" | |
32 | ||
33 | /* | |
34 | * DMA-BUF/GEM Object references and lifetime overview: | |
35 | * | |
36 | * On the export the dma_buf holds a reference to the exporting GEM | |
37 | * object. It takes this reference in handle_to_fd_ioctl, when it | |
38 | * first calls .prime_export and stores the exporting GEM object in | |
39 | * the dma_buf priv. This reference is released when the dma_buf | |
40 | * object goes away in the driver .release function. | |
41 | * | |
42 | * On the import the importing GEM object holds a reference to the | |
43 | * dma_buf (which in turn holds a ref to the exporting GEM object). | |
44 | * It takes that reference in the fd_to_handle ioctl. | |
45 | * It calls dma_buf_get, creates an attachment to it and stores the | |
46 | * attachment in the GEM object. When this attachment is destroyed | |
47 | * when the imported object is destroyed, we remove the attachment | |
48 | * and drop the reference to the dma_buf. | |
49 | * | |
50 | * Thus the chain of references always flows in one direction | |
51 | * (avoiding loops): importing_gem -> dmabuf -> exporting_gem | |
52 | * | |
53 | * Self-importing: if userspace is using PRIME as a replacement for flink | |
54 | * then it will get a fd->handle request for a GEM object that it created. | |
55 | * Drivers should detect this situation and return back the gem object | |
56 | * from the dma-buf private. | |
57 | */ | |
58 | ||
59 | struct drm_prime_member { | |
60 | struct list_head entry; | |
61 | struct dma_buf *dma_buf; | |
62 | uint32_t handle; | |
63 | }; | |
64 | ||
65 | int drm_gem_prime_handle_to_fd(struct drm_device *dev, | |
66 | struct drm_file *file_priv, uint32_t handle, uint32_t flags, | |
67 | int *prime_fd) | |
68 | { | |
69 | struct drm_gem_object *obj; | |
70 | void *buf; | |
71 | ||
72 | obj = drm_gem_object_lookup(dev, file_priv, handle); | |
73 | if (!obj) | |
74 | return -ENOENT; | |
75 | ||
76 | mutex_lock(&file_priv->prime.lock); | |
77 | /* re-export the original imported object */ | |
78 | if (obj->import_attach) { | |
79 | get_dma_buf(obj->import_attach->dmabuf); | |
80 | *prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags); | |
81 | drm_gem_object_unreference_unlocked(obj); | |
82 | mutex_unlock(&file_priv->prime.lock); | |
83 | return 0; | |
84 | } | |
85 | ||
86 | if (obj->export_dma_buf) { | |
87 | get_dma_buf(obj->export_dma_buf); | |
88 | *prime_fd = dma_buf_fd(obj->export_dma_buf, flags); | |
89 | drm_gem_object_unreference_unlocked(obj); | |
90 | } else { | |
91 | buf = dev->driver->gem_prime_export(dev, obj, flags); | |
92 | if (IS_ERR(buf)) { | |
93 | /* normally the created dma-buf takes ownership of the ref, | |
94 | * but if that fails then drop the ref | |
95 | */ | |
96 | drm_gem_object_unreference_unlocked(obj); | |
97 | mutex_unlock(&file_priv->prime.lock); | |
98 | return PTR_ERR(buf); | |
99 | } | |
100 | obj->export_dma_buf = buf; | |
101 | *prime_fd = dma_buf_fd(buf, flags); | |
102 | } | |
103 | mutex_unlock(&file_priv->prime.lock); | |
104 | return 0; | |
105 | } | |
106 | EXPORT_SYMBOL(drm_gem_prime_handle_to_fd); | |
107 | ||
108 | int drm_gem_prime_fd_to_handle(struct drm_device *dev, | |
109 | struct drm_file *file_priv, int prime_fd, uint32_t *handle) | |
110 | { | |
111 | struct dma_buf *dma_buf; | |
112 | struct drm_gem_object *obj; | |
113 | int ret; | |
114 | ||
115 | dma_buf = dma_buf_get(prime_fd); | |
116 | if (IS_ERR(dma_buf)) | |
117 | return PTR_ERR(dma_buf); | |
118 | ||
119 | mutex_lock(&file_priv->prime.lock); | |
120 | ||
121 | ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime, | |
122 | dma_buf, handle); | |
123 | if (!ret) { | |
124 | ret = 0; | |
125 | goto out_put; | |
126 | } | |
127 | ||
128 | /* never seen this one, need to import */ | |
129 | obj = dev->driver->gem_prime_import(dev, dma_buf); | |
130 | if (IS_ERR(obj)) { | |
131 | ret = PTR_ERR(obj); | |
132 | goto out_put; | |
133 | } | |
134 | ||
135 | ret = drm_gem_handle_create(file_priv, obj, handle); | |
136 | drm_gem_object_unreference_unlocked(obj); | |
137 | if (ret) | |
138 | goto out_put; | |
139 | ||
140 | ret = drm_prime_add_imported_buf_handle(&file_priv->prime, | |
141 | dma_buf, *handle); | |
142 | if (ret) | |
143 | goto fail; | |
144 | ||
145 | mutex_unlock(&file_priv->prime.lock); | |
146 | return 0; | |
147 | ||
148 | fail: | |
149 | /* hmm, if driver attached, we are relying on the free-object path | |
150 | * to detach.. which seems ok.. | |
151 | */ | |
152 | drm_gem_object_handle_unreference_unlocked(obj); | |
153 | out_put: | |
154 | dma_buf_put(dma_buf); | |
155 | mutex_unlock(&file_priv->prime.lock); | |
156 | return ret; | |
157 | } | |
158 | EXPORT_SYMBOL(drm_gem_prime_fd_to_handle); | |
159 | ||
160 | int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, | |
161 | struct drm_file *file_priv) | |
162 | { | |
163 | struct drm_prime_handle *args = data; | |
164 | uint32_t flags; | |
165 | ||
166 | if (!drm_core_check_feature(dev, DRIVER_PRIME)) | |
167 | return -EINVAL; | |
168 | ||
169 | if (!dev->driver->prime_handle_to_fd) | |
170 | return -ENOSYS; | |
171 | ||
172 | /* check flags are valid */ | |
173 | if (args->flags & ~DRM_CLOEXEC) | |
174 | return -EINVAL; | |
175 | ||
176 | /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */ | |
177 | flags = args->flags & DRM_CLOEXEC; | |
178 | ||
179 | return dev->driver->prime_handle_to_fd(dev, file_priv, | |
180 | args->handle, flags, &args->fd); | |
181 | } | |
182 | ||
183 | int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, | |
184 | struct drm_file *file_priv) | |
185 | { | |
186 | struct drm_prime_handle *args = data; | |
187 | ||
188 | if (!drm_core_check_feature(dev, DRIVER_PRIME)) | |
189 | return -EINVAL; | |
190 | ||
191 | if (!dev->driver->prime_fd_to_handle) | |
192 | return -ENOSYS; | |
193 | ||
194 | return dev->driver->prime_fd_to_handle(dev, file_priv, | |
195 | args->fd, &args->handle); | |
196 | } | |
197 | ||
198 | /* | |
199 | * drm_prime_pages_to_sg | |
200 | * | |
201 | * this helper creates an sg table object from a set of pages | |
202 | * the driver is responsible for mapping the pages into the | |
203 | * importers address space | |
204 | */ | |
205 | struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages) | |
206 | { | |
207 | struct sg_table *sg = NULL; | |
208 | struct scatterlist *iter; | |
209 | int i; | |
210 | int ret; | |
211 | ||
212 | sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); | |
213 | if (!sg) | |
214 | goto out; | |
215 | ||
216 | ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL); | |
217 | if (ret) | |
218 | goto out; | |
219 | ||
220 | for_each_sg(sg->sgl, iter, nr_pages, i) | |
221 | sg_set_page(iter, pages[i], PAGE_SIZE, 0); | |
222 | ||
223 | return sg; | |
224 | out: | |
225 | kfree(sg); | |
226 | return NULL; | |
227 | } | |
228 | EXPORT_SYMBOL(drm_prime_pages_to_sg); | |
229 | ||
230 | /* helper function to cleanup a GEM/prime object */ | |
231 | void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg) | |
232 | { | |
233 | struct dma_buf_attachment *attach; | |
234 | struct dma_buf *dma_buf; | |
235 | attach = obj->import_attach; | |
236 | if (sg) | |
237 | dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL); | |
238 | dma_buf = attach->dmabuf; | |
239 | dma_buf_detach(attach->dmabuf, attach); | |
240 | /* remove the reference */ | |
241 | dma_buf_put(dma_buf); | |
242 | } | |
243 | EXPORT_SYMBOL(drm_prime_gem_destroy); | |
244 | ||
245 | void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv) | |
246 | { | |
247 | INIT_LIST_HEAD(&prime_fpriv->head); | |
248 | mutex_init(&prime_fpriv->lock); | |
249 | } | |
250 | EXPORT_SYMBOL(drm_prime_init_file_private); | |
251 | ||
252 | void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv) | |
253 | { | |
254 | struct drm_prime_member *member, *safe; | |
255 | list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { | |
256 | list_del(&member->entry); | |
257 | kfree(member); | |
258 | } | |
259 | } | |
260 | EXPORT_SYMBOL(drm_prime_destroy_file_private); | |
261 | ||
262 | int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) | |
263 | { | |
264 | struct drm_prime_member *member; | |
265 | ||
266 | member = kmalloc(sizeof(*member), GFP_KERNEL); | |
267 | if (!member) | |
268 | return -ENOMEM; | |
269 | ||
270 | member->dma_buf = dma_buf; | |
271 | member->handle = handle; | |
272 | list_add(&member->entry, &prime_fpriv->head); | |
273 | return 0; | |
274 | } | |
275 | EXPORT_SYMBOL(drm_prime_add_imported_buf_handle); | |
276 | ||
277 | int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) | |
278 | { | |
279 | struct drm_prime_member *member; | |
280 | ||
281 | list_for_each_entry(member, &prime_fpriv->head, entry) { | |
282 | if (member->dma_buf == dma_buf) { | |
283 | *handle = member->handle; | |
284 | return 0; | |
285 | } | |
286 | } | |
287 | return -ENOENT; | |
288 | } | |
289 | EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle); | |
290 | ||
291 | void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) | |
292 | { | |
293 | struct drm_prime_member *member, *safe; | |
294 | ||
295 | mutex_lock(&prime_fpriv->lock); | |
296 | list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { | |
297 | if (member->dma_buf == dma_buf) { | |
298 | list_del(&member->entry); | |
299 | kfree(member); | |
300 | } | |
301 | } | |
302 | mutex_unlock(&prime_fpriv->lock); | |
303 | } | |
304 | EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle); |