2 * Copyright © 2012 Red Hat
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:
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
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
24 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
29 #include <linux/dma-buf.h>
33 * DMA-BUF/GEM Object references and lifetime overview:
35 * On the export the dma_buf holds a reference to the exporting GEM
36 * object. It takes this reference in handle_to_fd_ioctl, when it
37 * first calls .prime_export and stores the exporting GEM object in
38 * the dma_buf priv. This reference is released when the dma_buf
39 * object goes away in the driver .release function.
41 * On the import the importing GEM object holds a reference to the
42 * dma_buf (which in turn holds a ref to the exporting GEM object).
43 * It takes that reference in the fd_to_handle ioctl.
44 * It calls dma_buf_get, creates an attachment to it and stores the
45 * attachment in the GEM object. When this attachment is destroyed
46 * when the imported object is destroyed, we remove the attachment
47 * and drop the reference to the dma_buf.
49 * Thus the chain of references always flows in one direction
50 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
52 * Self-importing: if userspace is using PRIME as a replacement for flink
53 * then it will get a fd->handle request for a GEM object that it created.
54 * Drivers should detect this situation and return back the gem object
55 * from the dma-buf private.
58 struct drm_prime_member {
59 struct list_head entry;
60 struct dma_buf *dma_buf;
63 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
65 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
66 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
69 struct drm_gem_object *obj;
72 struct dma_buf *dmabuf;
74 obj = drm_gem_object_lookup(dev, file_priv, handle);
78 mutex_lock(&file_priv->prime.lock);
79 /* re-export the original imported object */
80 if (obj->import_attach) {
81 dmabuf = obj->import_attach->dmabuf;
85 if (obj->export_dma_buf) {
86 dmabuf = obj->export_dma_buf;
88 ret = drm_prime_add_buf_handle(&file_priv->prime,
93 buf = dev->driver->gem_prime_export(dev, obj, flags);
95 /* normally the created dma-buf takes ownership of the ref,
96 * but if that fails then drop the ref
101 obj->export_dma_buf = buf;
103 /* if we've exported this buffer the cheat and add it to the import list
104 * so we get the correct handle back
106 ret = drm_prime_add_buf_handle(&file_priv->prime,
107 obj->export_dma_buf, handle);
111 *prime_fd = dma_buf_fd(buf, flags);
112 mutex_unlock(&file_priv->prime.lock);
117 *prime_fd = dma_buf_fd(dmabuf, flags);
119 drm_gem_object_unreference_unlocked(obj);
120 mutex_unlock(&file_priv->prime.lock);
123 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
125 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
126 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
128 struct dma_buf *dma_buf;
129 struct drm_gem_object *obj;
132 dma_buf = dma_buf_get(prime_fd);
134 return PTR_ERR(dma_buf);
136 mutex_lock(&file_priv->prime.lock);
138 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
145 /* never seen this one, need to import */
146 obj = dev->driver->gem_prime_import(dev, dma_buf);
152 ret = drm_gem_handle_create(file_priv, obj, handle);
153 drm_gem_object_unreference_unlocked(obj);
157 ret = drm_prime_add_buf_handle(&file_priv->prime,
162 mutex_unlock(&file_priv->prime.lock);
166 /* hmm, if driver attached, we are relying on the free-object path
167 * to detach.. which seems ok..
169 drm_gem_object_handle_unreference_unlocked(obj);
171 dma_buf_put(dma_buf);
172 mutex_unlock(&file_priv->prime.lock);
175 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
177 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
178 struct drm_file *file_priv)
180 struct drm_prime_handle *args = data;
183 if (!drm_core_check_feature(dev, DRIVER_PRIME))
186 if (!dev->driver->prime_handle_to_fd)
189 /* check flags are valid */
190 if (args->flags & ~DRM_CLOEXEC)
193 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
194 flags = args->flags & DRM_CLOEXEC;
196 return dev->driver->prime_handle_to_fd(dev, file_priv,
197 args->handle, flags, &args->fd);
200 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
201 struct drm_file *file_priv)
203 struct drm_prime_handle *args = data;
205 if (!drm_core_check_feature(dev, DRIVER_PRIME))
208 if (!dev->driver->prime_fd_to_handle)
211 return dev->driver->prime_fd_to_handle(dev, file_priv,
212 args->fd, &args->handle);
216 * drm_prime_pages_to_sg
218 * this helper creates an sg table object from a set of pages
219 * the driver is responsible for mapping the pages into the
220 * importers address space
222 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
224 struct sg_table *sg = NULL;
225 struct scatterlist *iter;
229 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
233 ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL);
237 for_each_sg(sg->sgl, iter, nr_pages, i)
238 sg_set_page(iter, pages[i], PAGE_SIZE, 0);
245 EXPORT_SYMBOL(drm_prime_pages_to_sg);
247 /* helper function to cleanup a GEM/prime object */
248 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
250 struct dma_buf_attachment *attach;
251 struct dma_buf *dma_buf;
252 attach = obj->import_attach;
254 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
255 dma_buf = attach->dmabuf;
256 dma_buf_detach(attach->dmabuf, attach);
257 /* remove the reference */
258 dma_buf_put(dma_buf);
260 EXPORT_SYMBOL(drm_prime_gem_destroy);
262 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
264 INIT_LIST_HEAD(&prime_fpriv->head);
265 mutex_init(&prime_fpriv->lock);
267 EXPORT_SYMBOL(drm_prime_init_file_private);
269 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
271 struct drm_prime_member *member, *safe;
272 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
273 list_del(&member->entry);
277 EXPORT_SYMBOL(drm_prime_destroy_file_private);
279 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
281 struct drm_prime_member *member;
283 member = kmalloc(sizeof(*member), GFP_KERNEL);
287 get_dma_buf(dma_buf);
288 member->dma_buf = dma_buf;
289 member->handle = handle;
290 list_add(&member->entry, &prime_fpriv->head);
294 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
296 struct drm_prime_member *member;
298 list_for_each_entry(member, &prime_fpriv->head, entry) {
299 if (member->dma_buf == dma_buf) {
300 *handle = member->handle;
306 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
308 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
310 struct drm_prime_member *member, *safe;
312 mutex_lock(&prime_fpriv->lock);
313 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
314 if (member->dma_buf == dma_buf) {
315 dma_buf_put(dma_buf);
316 list_del(&member->entry);
320 mutex_unlock(&prime_fpriv->lock);
322 EXPORT_SYMBOL(drm_prime_remove_buf_handle);