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/export.h>
30 #include <linux/dma-buf.h>
34 * DMA-BUF/GEM Object references and lifetime overview:
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.
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.
50 * Thus the chain of references always flows in one direction
51 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
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. Prime will do this automatically for drivers that
57 * use the drm_gem_prime_{import,export} helpers.
60 struct drm_prime_member
{
61 struct list_head entry
;
62 struct dma_buf
*dma_buf
;
66 struct drm_prime_attachment
{
68 enum dma_data_direction dir
;
71 static int drm_prime_add_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
, uint32_t handle
)
73 struct drm_prime_member
*member
;
75 member
= kmalloc(sizeof(*member
), GFP_KERNEL
);
80 member
->dma_buf
= dma_buf
;
81 member
->handle
= handle
;
82 list_add(&member
->entry
, &prime_fpriv
->head
);
86 static struct dma_buf
*drm_prime_lookup_buf_by_handle(struct drm_prime_file_private
*prime_fpriv
,
89 struct drm_prime_member
*member
;
91 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
92 if (member
->handle
== handle
)
93 return member
->dma_buf
;
99 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private
*prime_fpriv
,
100 struct dma_buf
*dma_buf
,
103 struct drm_prime_member
*member
;
105 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
106 if (member
->dma_buf
== dma_buf
) {
107 *handle
= member
->handle
;
114 static int drm_gem_map_attach(struct dma_buf
*dma_buf
,
115 struct device
*target_dev
,
116 struct dma_buf_attachment
*attach
)
118 struct drm_prime_attachment
*prime_attach
;
119 struct drm_gem_object
*obj
= dma_buf
->priv
;
120 struct drm_device
*dev
= obj
->dev
;
122 prime_attach
= kzalloc(sizeof(*prime_attach
), GFP_KERNEL
);
126 prime_attach
->dir
= DMA_NONE
;
127 attach
->priv
= prime_attach
;
129 if (!dev
->driver
->gem_prime_pin
)
132 return dev
->driver
->gem_prime_pin(obj
);
135 static void drm_gem_map_detach(struct dma_buf
*dma_buf
,
136 struct dma_buf_attachment
*attach
)
138 struct drm_prime_attachment
*prime_attach
= attach
->priv
;
139 struct drm_gem_object
*obj
= dma_buf
->priv
;
140 struct drm_device
*dev
= obj
->dev
;
141 struct sg_table
*sgt
;
143 if (dev
->driver
->gem_prime_unpin
)
144 dev
->driver
->gem_prime_unpin(obj
);
149 sgt
= prime_attach
->sgt
;
151 if (prime_attach
->dir
!= DMA_NONE
)
152 dma_unmap_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
,
162 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private
*prime_fpriv
,
163 struct dma_buf
*dma_buf
)
165 struct drm_prime_member
*member
, *safe
;
167 list_for_each_entry_safe(member
, safe
, &prime_fpriv
->head
, entry
) {
168 if (member
->dma_buf
== dma_buf
) {
169 dma_buf_put(dma_buf
);
170 list_del(&member
->entry
);
176 static struct sg_table
*drm_gem_map_dma_buf(struct dma_buf_attachment
*attach
,
177 enum dma_data_direction dir
)
179 struct drm_prime_attachment
*prime_attach
= attach
->priv
;
180 struct drm_gem_object
*obj
= attach
->dmabuf
->priv
;
181 struct sg_table
*sgt
;
183 if (WARN_ON(dir
== DMA_NONE
|| !prime_attach
))
184 return ERR_PTR(-EINVAL
);
186 /* return the cached mapping when possible */
187 if (prime_attach
->dir
== dir
)
188 return prime_attach
->sgt
;
191 * two mappings with different directions for the same attachment are
194 if (WARN_ON(prime_attach
->dir
!= DMA_NONE
))
195 return ERR_PTR(-EBUSY
);
197 sgt
= obj
->dev
->driver
->gem_prime_get_sg_table(obj
);
200 if (!dma_map_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
, dir
)) {
203 sgt
= ERR_PTR(-ENOMEM
);
205 prime_attach
->sgt
= sgt
;
206 prime_attach
->dir
= dir
;
213 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment
*attach
,
214 struct sg_table
*sgt
, enum dma_data_direction dir
)
216 /* nothing to be done here */
219 void drm_gem_dmabuf_release(struct dma_buf
*dma_buf
)
221 struct drm_gem_object
*obj
= dma_buf
->priv
;
223 /* drop the reference on the export fd holds */
224 drm_gem_object_unreference_unlocked(obj
);
226 EXPORT_SYMBOL(drm_gem_dmabuf_release
);
228 static void *drm_gem_dmabuf_vmap(struct dma_buf
*dma_buf
)
230 struct drm_gem_object
*obj
= dma_buf
->priv
;
231 struct drm_device
*dev
= obj
->dev
;
233 return dev
->driver
->gem_prime_vmap(obj
);
236 static void drm_gem_dmabuf_vunmap(struct dma_buf
*dma_buf
, void *vaddr
)
238 struct drm_gem_object
*obj
= dma_buf
->priv
;
239 struct drm_device
*dev
= obj
->dev
;
241 dev
->driver
->gem_prime_vunmap(obj
, vaddr
);
244 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf
*dma_buf
,
245 unsigned long page_num
)
250 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf
*dma_buf
,
251 unsigned long page_num
, void *addr
)
255 static void *drm_gem_dmabuf_kmap(struct dma_buf
*dma_buf
,
256 unsigned long page_num
)
261 static void drm_gem_dmabuf_kunmap(struct dma_buf
*dma_buf
,
262 unsigned long page_num
, void *addr
)
267 static int drm_gem_dmabuf_mmap(struct dma_buf
*dma_buf
,
268 struct vm_area_struct
*vma
)
270 struct drm_gem_object
*obj
= dma_buf
->priv
;
271 struct drm_device
*dev
= obj
->dev
;
273 if (!dev
->driver
->gem_prime_mmap
)
276 return dev
->driver
->gem_prime_mmap(obj
, vma
);
279 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops
= {
280 .attach
= drm_gem_map_attach
,
281 .detach
= drm_gem_map_detach
,
282 .map_dma_buf
= drm_gem_map_dma_buf
,
283 .unmap_dma_buf
= drm_gem_unmap_dma_buf
,
284 .release
= drm_gem_dmabuf_release
,
285 .kmap
= drm_gem_dmabuf_kmap
,
286 .kmap_atomic
= drm_gem_dmabuf_kmap_atomic
,
287 .kunmap
= drm_gem_dmabuf_kunmap
,
288 .kunmap_atomic
= drm_gem_dmabuf_kunmap_atomic
,
289 .mmap
= drm_gem_dmabuf_mmap
,
290 .vmap
= drm_gem_dmabuf_vmap
,
291 .vunmap
= drm_gem_dmabuf_vunmap
,
297 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
298 * simpler APIs by using the helper functions @drm_gem_prime_export and
299 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
300 * five lower-level driver callbacks:
304 * - @gem_prime_pin (optional): prepare a GEM object for exporting
306 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
308 * - @gem_prime_vmap: vmap a buffer exported by your driver
310 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
314 * - @gem_prime_import_sg_table (import): produce a GEM object from another
315 * driver's scatter/gather table
318 struct dma_buf
*drm_gem_prime_export(struct drm_device
*dev
,
319 struct drm_gem_object
*obj
, int flags
)
321 return dma_buf_export(obj
, &drm_gem_prime_dmabuf_ops
, obj
->size
, flags
);
323 EXPORT_SYMBOL(drm_gem_prime_export
);
325 static struct dma_buf
*export_and_register_object(struct drm_device
*dev
,
326 struct drm_gem_object
*obj
,
329 struct dma_buf
*dmabuf
;
331 /* prevent races with concurrent gem_close. */
332 if (obj
->handle_count
== 0) {
333 dmabuf
= ERR_PTR(-ENOENT
);
337 dmabuf
= dev
->driver
->gem_prime_export(dev
, obj
, flags
);
338 if (IS_ERR(dmabuf
)) {
339 /* normally the created dma-buf takes ownership of the ref,
340 * but if that fails then drop the ref
346 * Note that callers do not need to clean up the export cache
347 * since the check for obj->handle_count guarantees that someone
350 obj
->dma_buf
= dmabuf
;
351 get_dma_buf(obj
->dma_buf
);
352 /* Grab a new ref since the callers is now used by the dma-buf */
353 drm_gem_object_reference(obj
);
358 int drm_gem_prime_handle_to_fd(struct drm_device
*dev
,
359 struct drm_file
*file_priv
, uint32_t handle
, uint32_t flags
,
362 struct drm_gem_object
*obj
;
364 struct dma_buf
*dmabuf
;
366 mutex_lock(&file_priv
->prime
.lock
);
367 obj
= drm_gem_object_lookup(dev
, file_priv
, handle
);
373 dmabuf
= drm_prime_lookup_buf_by_handle(&file_priv
->prime
, handle
);
376 goto out_have_handle
;
379 mutex_lock(&dev
->object_name_lock
);
380 /* re-export the original imported object */
381 if (obj
->import_attach
) {
382 dmabuf
= obj
->import_attach
->dmabuf
;
388 get_dma_buf(obj
->dma_buf
);
389 dmabuf
= obj
->dma_buf
;
393 dmabuf
= export_and_register_object(dev
, obj
, flags
);
394 if (IS_ERR(dmabuf
)) {
395 /* normally the created dma-buf takes ownership of the ref,
396 * but if that fails then drop the ref
398 ret
= PTR_ERR(dmabuf
);
399 mutex_unlock(&dev
->object_name_lock
);
405 * If we've exported this buffer then cheat and add it to the import list
406 * so we get the correct handle back. We must do this under the
407 * protection of dev->object_name_lock to ensure that a racing gem close
408 * ioctl doesn't miss to remove this buffer handle from the cache.
410 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
412 mutex_unlock(&dev
->object_name_lock
);
414 goto fail_put_dmabuf
;
417 ret
= dma_buf_fd(dmabuf
, flags
);
419 * We must _not_ remove the buffer from the handle cache since the newly
420 * created dma buf is already linked in the global obj->dma_buf pointer,
421 * and that is invariant as long as a userspace gem handle exists.
422 * Closing the handle will clean out the cache anyway, so we don't leak.
425 goto fail_put_dmabuf
;
436 drm_gem_object_unreference_unlocked(obj
);
438 mutex_unlock(&file_priv
->prime
.lock
);
442 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd
);
444 struct drm_gem_object
*drm_gem_prime_import(struct drm_device
*dev
,
445 struct dma_buf
*dma_buf
)
447 struct dma_buf_attachment
*attach
;
448 struct sg_table
*sgt
;
449 struct drm_gem_object
*obj
;
452 if (!dev
->driver
->gem_prime_import_sg_table
)
453 return ERR_PTR(-EINVAL
);
455 if (dma_buf
->ops
== &drm_gem_prime_dmabuf_ops
) {
457 if (obj
->dev
== dev
) {
459 * Importing dmabuf exported from out own gem increases
460 * refcount on gem itself instead of f_count of dmabuf.
462 drm_gem_object_reference(obj
);
467 attach
= dma_buf_attach(dma_buf
, dev
->dev
);
469 return ERR_CAST(attach
);
471 get_dma_buf(dma_buf
);
473 sgt
= dma_buf_map_attachment(attach
, DMA_BIDIRECTIONAL
);
474 if (IS_ERR_OR_NULL(sgt
)) {
479 obj
= dev
->driver
->gem_prime_import_sg_table(dev
, dma_buf
->size
, sgt
);
485 obj
->import_attach
= attach
;
490 dma_buf_unmap_attachment(attach
, sgt
, DMA_BIDIRECTIONAL
);
492 dma_buf_detach(dma_buf
, attach
);
493 dma_buf_put(dma_buf
);
497 EXPORT_SYMBOL(drm_gem_prime_import
);
499 int drm_gem_prime_fd_to_handle(struct drm_device
*dev
,
500 struct drm_file
*file_priv
, int prime_fd
, uint32_t *handle
)
502 struct dma_buf
*dma_buf
;
503 struct drm_gem_object
*obj
;
506 dma_buf
= dma_buf_get(prime_fd
);
508 return PTR_ERR(dma_buf
);
510 mutex_lock(&file_priv
->prime
.lock
);
512 ret
= drm_prime_lookup_buf_handle(&file_priv
->prime
,
517 /* never seen this one, need to import */
518 mutex_lock(&dev
->object_name_lock
);
519 obj
= dev
->driver
->gem_prime_import(dev
, dma_buf
);
526 WARN_ON(obj
->dma_buf
!= dma_buf
);
528 obj
->dma_buf
= dma_buf
;
529 get_dma_buf(dma_buf
);
532 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
533 ret
= drm_gem_handle_create_tail(file_priv
, obj
, handle
);
534 drm_gem_object_unreference_unlocked(obj
);
538 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
543 mutex_unlock(&file_priv
->prime
.lock
);
545 dma_buf_put(dma_buf
);
550 /* hmm, if driver attached, we are relying on the free-object path
551 * to detach.. which seems ok..
553 drm_gem_handle_delete(file_priv
, *handle
);
555 mutex_unlock(&dev
->object_name_lock
);
557 dma_buf_put(dma_buf
);
558 mutex_unlock(&file_priv
->prime
.lock
);
561 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle
);
563 int drm_prime_handle_to_fd_ioctl(struct drm_device
*dev
, void *data
,
564 struct drm_file
*file_priv
)
566 struct drm_prime_handle
*args
= data
;
569 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
572 if (!dev
->driver
->prime_handle_to_fd
)
575 /* check flags are valid */
576 if (args
->flags
& ~DRM_CLOEXEC
)
579 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
580 flags
= args
->flags
& DRM_CLOEXEC
;
582 return dev
->driver
->prime_handle_to_fd(dev
, file_priv
,
583 args
->handle
, flags
, &args
->fd
);
586 int drm_prime_fd_to_handle_ioctl(struct drm_device
*dev
, void *data
,
587 struct drm_file
*file_priv
)
589 struct drm_prime_handle
*args
= data
;
591 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
594 if (!dev
->driver
->prime_fd_to_handle
)
597 return dev
->driver
->prime_fd_to_handle(dev
, file_priv
,
598 args
->fd
, &args
->handle
);
602 * drm_prime_pages_to_sg
604 * this helper creates an sg table object from a set of pages
605 * the driver is responsible for mapping the pages into the
606 * importers address space
608 struct sg_table
*drm_prime_pages_to_sg(struct page
**pages
, int nr_pages
)
610 struct sg_table
*sg
= NULL
;
613 sg
= kmalloc(sizeof(struct sg_table
), GFP_KERNEL
);
619 ret
= sg_alloc_table_from_pages(sg
, pages
, nr_pages
, 0,
620 nr_pages
<< PAGE_SHIFT
, GFP_KERNEL
);
629 EXPORT_SYMBOL(drm_prime_pages_to_sg
);
631 /* export an sg table into an array of pages and addresses
632 this is currently required by the TTM driver in order to do correct fault
634 int drm_prime_sg_to_page_addr_arrays(struct sg_table
*sgt
, struct page
**pages
,
635 dma_addr_t
*addrs
, int max_pages
)
638 struct scatterlist
*sg
;
645 for_each_sg(sgt
->sgl
, sg
, sgt
->nents
, count
) {
649 addr
= sg_dma_address(sg
);
652 if (WARN_ON(pg_index
>= max_pages
))
654 pages
[pg_index
] = page
;
656 addrs
[pg_index
] = addr
;
666 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays
);
667 /* helper function to cleanup a GEM/prime object */
668 void drm_prime_gem_destroy(struct drm_gem_object
*obj
, struct sg_table
*sg
)
670 struct dma_buf_attachment
*attach
;
671 struct dma_buf
*dma_buf
;
672 attach
= obj
->import_attach
;
674 dma_buf_unmap_attachment(attach
, sg
, DMA_BIDIRECTIONAL
);
675 dma_buf
= attach
->dmabuf
;
676 dma_buf_detach(attach
->dmabuf
, attach
);
677 /* remove the reference */
678 dma_buf_put(dma_buf
);
680 EXPORT_SYMBOL(drm_prime_gem_destroy
);
682 void drm_prime_init_file_private(struct drm_prime_file_private
*prime_fpriv
)
684 INIT_LIST_HEAD(&prime_fpriv
->head
);
685 mutex_init(&prime_fpriv
->lock
);
687 EXPORT_SYMBOL(drm_prime_init_file_private
);
689 void drm_prime_destroy_file_private(struct drm_prime_file_private
*prime_fpriv
)
691 /* by now drm_gem_release should've made sure the list is empty */
692 WARN_ON(!list_empty(&prime_fpriv
->head
));
694 EXPORT_SYMBOL(drm_prime_destroy_file_private
);