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
,
72 struct dma_buf
*dma_buf
, uint32_t handle
)
74 struct drm_prime_member
*member
;
76 member
= kmalloc(sizeof(*member
), GFP_KERNEL
);
81 member
->dma_buf
= dma_buf
;
82 member
->handle
= handle
;
83 list_add(&member
->entry
, &prime_fpriv
->head
);
87 static struct dma_buf
*drm_prime_lookup_buf_by_handle(struct drm_prime_file_private
*prime_fpriv
,
90 struct drm_prime_member
*member
;
92 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
93 if (member
->handle
== handle
)
94 return member
->dma_buf
;
100 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private
*prime_fpriv
,
101 struct dma_buf
*dma_buf
,
104 struct drm_prime_member
*member
;
106 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
107 if (member
->dma_buf
== dma_buf
) {
108 *handle
= member
->handle
;
115 static int drm_gem_map_attach(struct dma_buf
*dma_buf
,
116 struct device
*target_dev
,
117 struct dma_buf_attachment
*attach
)
119 struct drm_prime_attachment
*prime_attach
;
120 struct drm_gem_object
*obj
= dma_buf
->priv
;
121 struct drm_device
*dev
= obj
->dev
;
123 prime_attach
= kzalloc(sizeof(*prime_attach
), GFP_KERNEL
);
127 prime_attach
->dir
= DMA_NONE
;
128 attach
->priv
= prime_attach
;
130 if (!dev
->driver
->gem_prime_pin
)
133 return dev
->driver
->gem_prime_pin(obj
);
136 static void drm_gem_map_detach(struct dma_buf
*dma_buf
,
137 struct dma_buf_attachment
*attach
)
139 struct drm_prime_attachment
*prime_attach
= attach
->priv
;
140 struct drm_gem_object
*obj
= dma_buf
->priv
;
141 struct drm_device
*dev
= obj
->dev
;
142 struct sg_table
*sgt
;
144 if (dev
->driver
->gem_prime_unpin
)
145 dev
->driver
->gem_prime_unpin(obj
);
150 sgt
= prime_attach
->sgt
;
152 if (prime_attach
->dir
!= DMA_NONE
)
153 dma_unmap_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
,
163 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private
*prime_fpriv
,
164 struct dma_buf
*dma_buf
)
166 struct drm_prime_member
*member
, *safe
;
168 list_for_each_entry_safe(member
, safe
, &prime_fpriv
->head
, entry
) {
169 if (member
->dma_buf
== dma_buf
) {
170 dma_buf_put(dma_buf
);
171 list_del(&member
->entry
);
177 static struct sg_table
*drm_gem_map_dma_buf(struct dma_buf_attachment
*attach
,
178 enum dma_data_direction dir
)
180 struct drm_prime_attachment
*prime_attach
= attach
->priv
;
181 struct drm_gem_object
*obj
= attach
->dmabuf
->priv
;
182 struct sg_table
*sgt
;
184 if (WARN_ON(dir
== DMA_NONE
|| !prime_attach
))
185 return ERR_PTR(-EINVAL
);
187 /* return the cached mapping when possible */
188 if (prime_attach
->dir
== dir
)
189 return prime_attach
->sgt
;
192 * two mappings with different directions for the same attachment are
195 if (WARN_ON(prime_attach
->dir
!= DMA_NONE
))
196 return ERR_PTR(-EBUSY
);
198 sgt
= obj
->dev
->driver
->gem_prime_get_sg_table(obj
);
201 if (!dma_map_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
, dir
)) {
204 sgt
= ERR_PTR(-ENOMEM
);
206 prime_attach
->sgt
= sgt
;
207 prime_attach
->dir
= dir
;
214 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment
*attach
,
215 struct sg_table
*sgt
,
216 enum dma_data_direction dir
)
218 /* nothing to be done here */
222 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
223 * @dma_buf: buffer to be released
225 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
226 * must use this in their dma_buf ops structure as the release callback.
228 void drm_gem_dmabuf_release(struct dma_buf
*dma_buf
)
230 struct drm_gem_object
*obj
= dma_buf
->priv
;
232 /* drop the reference on the export fd holds */
233 drm_gem_object_unreference_unlocked(obj
);
235 EXPORT_SYMBOL(drm_gem_dmabuf_release
);
237 static void *drm_gem_dmabuf_vmap(struct dma_buf
*dma_buf
)
239 struct drm_gem_object
*obj
= dma_buf
->priv
;
240 struct drm_device
*dev
= obj
->dev
;
242 return dev
->driver
->gem_prime_vmap(obj
);
245 static void drm_gem_dmabuf_vunmap(struct dma_buf
*dma_buf
, void *vaddr
)
247 struct drm_gem_object
*obj
= dma_buf
->priv
;
248 struct drm_device
*dev
= obj
->dev
;
250 dev
->driver
->gem_prime_vunmap(obj
, vaddr
);
253 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf
*dma_buf
,
254 unsigned long page_num
)
259 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf
*dma_buf
,
260 unsigned long page_num
, void *addr
)
264 static void *drm_gem_dmabuf_kmap(struct dma_buf
*dma_buf
,
265 unsigned long page_num
)
270 static void drm_gem_dmabuf_kunmap(struct dma_buf
*dma_buf
,
271 unsigned long page_num
, void *addr
)
276 static int drm_gem_dmabuf_mmap(struct dma_buf
*dma_buf
,
277 struct vm_area_struct
*vma
)
279 struct drm_gem_object
*obj
= dma_buf
->priv
;
280 struct drm_device
*dev
= obj
->dev
;
282 if (!dev
->driver
->gem_prime_mmap
)
285 return dev
->driver
->gem_prime_mmap(obj
, vma
);
288 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops
= {
289 .attach
= drm_gem_map_attach
,
290 .detach
= drm_gem_map_detach
,
291 .map_dma_buf
= drm_gem_map_dma_buf
,
292 .unmap_dma_buf
= drm_gem_unmap_dma_buf
,
293 .release
= drm_gem_dmabuf_release
,
294 .kmap
= drm_gem_dmabuf_kmap
,
295 .kmap_atomic
= drm_gem_dmabuf_kmap_atomic
,
296 .kunmap
= drm_gem_dmabuf_kunmap
,
297 .kunmap_atomic
= drm_gem_dmabuf_kunmap_atomic
,
298 .mmap
= drm_gem_dmabuf_mmap
,
299 .vmap
= drm_gem_dmabuf_vmap
,
300 .vunmap
= drm_gem_dmabuf_vunmap
,
306 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
307 * simpler APIs by using the helper functions @drm_gem_prime_export and
308 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
309 * five lower-level driver callbacks:
313 * - @gem_prime_pin (optional): prepare a GEM object for exporting
315 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
317 * - @gem_prime_vmap: vmap a buffer exported by your driver
319 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
323 * - @gem_prime_import_sg_table (import): produce a GEM object from another
324 * driver's scatter/gather table
328 * drm_gem_prime_export - helper library implemention of the export callback
329 * @dev: drm_device to export from
330 * @obj: GEM object to export
331 * @flags: flags like DRM_CLOEXEC
333 * This is the implementation of the gem_prime_export functions for GEM drivers
334 * using the PRIME helpers.
336 struct dma_buf
*drm_gem_prime_export(struct drm_device
*dev
,
337 struct drm_gem_object
*obj
, int flags
)
339 return dma_buf_export(obj
, &drm_gem_prime_dmabuf_ops
, obj
->size
, flags
);
341 EXPORT_SYMBOL(drm_gem_prime_export
);
343 static struct dma_buf
*export_and_register_object(struct drm_device
*dev
,
344 struct drm_gem_object
*obj
,
347 struct dma_buf
*dmabuf
;
349 /* prevent races with concurrent gem_close. */
350 if (obj
->handle_count
== 0) {
351 dmabuf
= ERR_PTR(-ENOENT
);
355 dmabuf
= dev
->driver
->gem_prime_export(dev
, obj
, flags
);
356 if (IS_ERR(dmabuf
)) {
357 /* normally the created dma-buf takes ownership of the ref,
358 * but if that fails then drop the ref
364 * Note that callers do not need to clean up the export cache
365 * since the check for obj->handle_count guarantees that someone
368 obj
->dma_buf
= dmabuf
;
369 get_dma_buf(obj
->dma_buf
);
370 /* Grab a new ref since the callers is now used by the dma-buf */
371 drm_gem_object_reference(obj
);
377 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
378 * @dev: dev to export the buffer from
379 * @file_priv: drm file-private structure
380 * @handle: buffer handle to export
381 * @flags: flags like DRM_CLOEXEC
382 * @prime_fd: pointer to storage for the fd id of the create dma-buf
384 * This is the PRIME export function which must be used mandatorily by GEM
385 * drivers to ensure correct lifetime management of the underlying GEM object.
386 * The actual exporting from GEM object to a dma-buf is done through the
387 * gem_prime_export driver callback.
389 int drm_gem_prime_handle_to_fd(struct drm_device
*dev
,
390 struct drm_file
*file_priv
, uint32_t handle
,
394 struct drm_gem_object
*obj
;
396 struct dma_buf
*dmabuf
;
398 mutex_lock(&file_priv
->prime
.lock
);
399 obj
= drm_gem_object_lookup(dev
, file_priv
, handle
);
405 dmabuf
= drm_prime_lookup_buf_by_handle(&file_priv
->prime
, handle
);
408 goto out_have_handle
;
411 mutex_lock(&dev
->object_name_lock
);
412 /* re-export the original imported object */
413 if (obj
->import_attach
) {
414 dmabuf
= obj
->import_attach
->dmabuf
;
420 get_dma_buf(obj
->dma_buf
);
421 dmabuf
= obj
->dma_buf
;
425 dmabuf
= export_and_register_object(dev
, obj
, flags
);
426 if (IS_ERR(dmabuf
)) {
427 /* normally the created dma-buf takes ownership of the ref,
428 * but if that fails then drop the ref
430 ret
= PTR_ERR(dmabuf
);
431 mutex_unlock(&dev
->object_name_lock
);
437 * If we've exported this buffer then cheat and add it to the import list
438 * so we get the correct handle back. We must do this under the
439 * protection of dev->object_name_lock to ensure that a racing gem close
440 * ioctl doesn't miss to remove this buffer handle from the cache.
442 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
444 mutex_unlock(&dev
->object_name_lock
);
446 goto fail_put_dmabuf
;
449 ret
= dma_buf_fd(dmabuf
, flags
);
451 * We must _not_ remove the buffer from the handle cache since the newly
452 * created dma buf is already linked in the global obj->dma_buf pointer,
453 * and that is invariant as long as a userspace gem handle exists.
454 * Closing the handle will clean out the cache anyway, so we don't leak.
457 goto fail_put_dmabuf
;
468 drm_gem_object_unreference_unlocked(obj
);
470 mutex_unlock(&file_priv
->prime
.lock
);
474 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd
);
477 * drm_gem_prime_import - helper library implemention of the import callback
478 * @dev: drm_device to import into
479 * @dma_buf: dma-buf object to import
481 * This is the implementation of the gem_prime_import functions for GEM drivers
482 * using the PRIME helpers.
484 struct drm_gem_object
*drm_gem_prime_import(struct drm_device
*dev
,
485 struct dma_buf
*dma_buf
)
487 struct dma_buf_attachment
*attach
;
488 struct sg_table
*sgt
;
489 struct drm_gem_object
*obj
;
492 if (!dev
->driver
->gem_prime_import_sg_table
)
493 return ERR_PTR(-EINVAL
);
495 if (dma_buf
->ops
== &drm_gem_prime_dmabuf_ops
) {
497 if (obj
->dev
== dev
) {
499 * Importing dmabuf exported from out own gem increases
500 * refcount on gem itself instead of f_count of dmabuf.
502 drm_gem_object_reference(obj
);
507 attach
= dma_buf_attach(dma_buf
, dev
->dev
);
509 return ERR_CAST(attach
);
511 get_dma_buf(dma_buf
);
513 sgt
= dma_buf_map_attachment(attach
, DMA_BIDIRECTIONAL
);
519 obj
= dev
->driver
->gem_prime_import_sg_table(dev
, dma_buf
->size
, sgt
);
525 obj
->import_attach
= attach
;
530 dma_buf_unmap_attachment(attach
, sgt
, DMA_BIDIRECTIONAL
);
532 dma_buf_detach(dma_buf
, attach
);
533 dma_buf_put(dma_buf
);
537 EXPORT_SYMBOL(drm_gem_prime_import
);
540 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
541 * @dev: dev to export the buffer from
542 * @file_priv: drm file-private structure
543 * @prime_fd: fd id of the dma-buf which should be imported
544 * @handle: pointer to storage for the handle of the imported buffer object
546 * This is the PRIME import function which must be used mandatorily by GEM
547 * drivers to ensure correct lifetime management of the underlying GEM object.
548 * The actual importing of GEM object from the dma-buf is done through the
549 * gem_import_export driver callback.
551 int drm_gem_prime_fd_to_handle(struct drm_device
*dev
,
552 struct drm_file
*file_priv
, int prime_fd
,
555 struct dma_buf
*dma_buf
;
556 struct drm_gem_object
*obj
;
559 dma_buf
= dma_buf_get(prime_fd
);
561 return PTR_ERR(dma_buf
);
563 mutex_lock(&file_priv
->prime
.lock
);
565 ret
= drm_prime_lookup_buf_handle(&file_priv
->prime
,
570 /* never seen this one, need to import */
571 mutex_lock(&dev
->object_name_lock
);
572 obj
= dev
->driver
->gem_prime_import(dev
, dma_buf
);
579 WARN_ON(obj
->dma_buf
!= dma_buf
);
581 obj
->dma_buf
= dma_buf
;
582 get_dma_buf(dma_buf
);
585 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
586 ret
= drm_gem_handle_create_tail(file_priv
, obj
, handle
);
587 drm_gem_object_unreference_unlocked(obj
);
591 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
596 mutex_unlock(&file_priv
->prime
.lock
);
598 dma_buf_put(dma_buf
);
603 /* hmm, if driver attached, we are relying on the free-object path
604 * to detach.. which seems ok..
606 drm_gem_handle_delete(file_priv
, *handle
);
608 mutex_unlock(&dev
->object_name_lock
);
610 dma_buf_put(dma_buf
);
611 mutex_unlock(&file_priv
->prime
.lock
);
614 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle
);
616 int drm_prime_handle_to_fd_ioctl(struct drm_device
*dev
, void *data
,
617 struct drm_file
*file_priv
)
619 struct drm_prime_handle
*args
= data
;
622 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
625 if (!dev
->driver
->prime_handle_to_fd
)
628 /* check flags are valid */
629 if (args
->flags
& ~DRM_CLOEXEC
)
632 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
633 flags
= args
->flags
& DRM_CLOEXEC
;
635 return dev
->driver
->prime_handle_to_fd(dev
, file_priv
,
636 args
->handle
, flags
, &args
->fd
);
639 int drm_prime_fd_to_handle_ioctl(struct drm_device
*dev
, void *data
,
640 struct drm_file
*file_priv
)
642 struct drm_prime_handle
*args
= data
;
644 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
647 if (!dev
->driver
->prime_fd_to_handle
)
650 return dev
->driver
->prime_fd_to_handle(dev
, file_priv
,
651 args
->fd
, &args
->handle
);
655 * drm_prime_pages_to_sg - converts a page array into an sg list
656 * @pages: pointer to the array of page pointers to convert
657 * @nr_pages: length of the page vector
659 * This helper creates an sg table object from a set of pages
660 * the driver is responsible for mapping the pages into the
661 * importers address space for use with dma_buf itself.
663 struct sg_table
*drm_prime_pages_to_sg(struct page
**pages
, int nr_pages
)
665 struct sg_table
*sg
= NULL
;
668 sg
= kmalloc(sizeof(struct sg_table
), GFP_KERNEL
);
674 ret
= sg_alloc_table_from_pages(sg
, pages
, nr_pages
, 0,
675 nr_pages
<< PAGE_SHIFT
, GFP_KERNEL
);
684 EXPORT_SYMBOL(drm_prime_pages_to_sg
);
687 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
688 * @sgt: scatter-gather table to convert
689 * @pages: array of page pointers to store the page array in
690 * @addrs: optional array to store the dma bus address of each page
691 * @max_pages: size of both the passed-in arrays
693 * Exports an sg table into an array of pages and addresses. This is currently
694 * required by the TTM driver in order to do correct fault handling.
696 int drm_prime_sg_to_page_addr_arrays(struct sg_table
*sgt
, struct page
**pages
,
697 dma_addr_t
*addrs
, int max_pages
)
700 struct scatterlist
*sg
;
707 for_each_sg(sgt
->sgl
, sg
, sgt
->nents
, count
) {
710 addr
= sg_dma_address(sg
);
713 if (WARN_ON(pg_index
>= max_pages
))
715 pages
[pg_index
] = page
;
717 addrs
[pg_index
] = addr
;
727 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays
);
730 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
731 * @obj: GEM object which was created from a dma-buf
732 * @sg: the sg-table which was pinned at import time
734 * This is the cleanup functions which GEM drivers need to call when they use
735 * @drm_gem_prime_import to import dma-bufs.
737 void drm_prime_gem_destroy(struct drm_gem_object
*obj
, struct sg_table
*sg
)
739 struct dma_buf_attachment
*attach
;
740 struct dma_buf
*dma_buf
;
741 attach
= obj
->import_attach
;
743 dma_buf_unmap_attachment(attach
, sg
, DMA_BIDIRECTIONAL
);
744 dma_buf
= attach
->dmabuf
;
745 dma_buf_detach(attach
->dmabuf
, attach
);
746 /* remove the reference */
747 dma_buf_put(dma_buf
);
749 EXPORT_SYMBOL(drm_prime_gem_destroy
);
751 void drm_prime_init_file_private(struct drm_prime_file_private
*prime_fpriv
)
753 INIT_LIST_HEAD(&prime_fpriv
->head
);
754 mutex_init(&prime_fpriv
->lock
);
757 void drm_prime_destroy_file_private(struct drm_prime_file_private
*prime_fpriv
)
759 /* by now drm_gem_release should've made sure the list is empty */
760 WARN_ON(!list_empty(&prime_fpriv
->head
));