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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 <drm/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. Prime will do this automatically for drivers that
57 * use the drm_gem_prime_{import,export} helpers.
58 */
59
60struct drm_prime_member {
61 struct list_head entry;
62 struct dma_buf *dma_buf;
63 uint32_t handle;
64};
65
66struct drm_prime_attachment {
67 struct sg_table *sgt;
68 enum dma_data_direction dir;
69};
70
71static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
72 struct dma_buf *dma_buf, uint32_t handle)
73{
74 struct drm_prime_member *member;
75
76 member = kmalloc(sizeof(*member), GFP_KERNEL);
77 if (!member)
78 return -ENOMEM;
79
80 get_dma_buf(dma_buf);
81 member->dma_buf = dma_buf;
82 member->handle = handle;
83 list_add(&member->entry, &prime_fpriv->head);
84 return 0;
85}
86
87static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
88 uint32_t handle)
89{
90 struct drm_prime_member *member;
91
92 list_for_each_entry(member, &prime_fpriv->head, entry) {
93 if (member->handle == handle)
94 return member->dma_buf;
95 }
96
97 return NULL;
98}
99
100static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
101 struct dma_buf *dma_buf,
102 uint32_t *handle)
103{
104 struct drm_prime_member *member;
105
106 list_for_each_entry(member, &prime_fpriv->head, entry) {
107 if (member->dma_buf == dma_buf) {
108 *handle = member->handle;
109 return 0;
110 }
111 }
112 return -ENOENT;
113}
114
115static int drm_gem_map_attach(struct dma_buf *dma_buf,
116 struct device *target_dev,
117 struct dma_buf_attachment *attach)
118{
119 struct drm_prime_attachment *prime_attach;
120 struct drm_gem_object *obj = dma_buf->priv;
121 struct drm_device *dev = obj->dev;
122
123 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
124 if (!prime_attach)
125 return -ENOMEM;
126
127 prime_attach->dir = DMA_NONE;
128 attach->priv = prime_attach;
129
130 if (!dev->driver->gem_prime_pin)
131 return 0;
132
133 return dev->driver->gem_prime_pin(obj);
134}
135
136static void drm_gem_map_detach(struct dma_buf *dma_buf,
137 struct dma_buf_attachment *attach)
138{
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;
143
144 if (dev->driver->gem_prime_unpin)
145 dev->driver->gem_prime_unpin(obj);
146
147 if (!prime_attach)
148 return;
149
150 sgt = prime_attach->sgt;
151 if (sgt) {
152 if (prime_attach->dir != DMA_NONE)
153 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
154 prime_attach->dir);
155 sg_free_table(sgt);
156 }
157
158 kfree(sgt);
159 kfree(prime_attach);
160 attach->priv = NULL;
161}
162
163void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
164 struct dma_buf *dma_buf)
165{
166 struct drm_prime_member *member, *safe;
167
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);
172 kfree(member);
173 }
174 }
175}
176
177static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
178 enum dma_data_direction dir)
179{
180 struct drm_prime_attachment *prime_attach = attach->priv;
181 struct drm_gem_object *obj = attach->dmabuf->priv;
182 struct sg_table *sgt;
183
184 if (WARN_ON(dir == DMA_NONE || !prime_attach))
185 return ERR_PTR(-EINVAL);
186
187 /* return the cached mapping when possible */
188 if (prime_attach->dir == dir)
189 return prime_attach->sgt;
190
191 /*
192 * two mappings with different directions for the same attachment are
193 * not allowed
194 */
195 if (WARN_ON(prime_attach->dir != DMA_NONE))
196 return ERR_PTR(-EBUSY);
197
198 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
199
200 if (!IS_ERR(sgt)) {
201 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
202 sg_free_table(sgt);
203 kfree(sgt);
204 sgt = ERR_PTR(-ENOMEM);
205 } else {
206 prime_attach->sgt = sgt;
207 prime_attach->dir = dir;
208 }
209 }
210
211 return sgt;
212}
213
214static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
215 struct sg_table *sgt,
216 enum dma_data_direction dir)
217{
218 /* nothing to be done here */
219}
220
221/**
222 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
223 * @dma_buf: buffer to be released
224 *
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.
227 */
228void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
229{
230 struct drm_gem_object *obj = dma_buf->priv;
231
232 /* drop the reference on the export fd holds */
233 drm_gem_object_unreference_unlocked(obj);
234}
235EXPORT_SYMBOL(drm_gem_dmabuf_release);
236
237static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
238{
239 struct drm_gem_object *obj = dma_buf->priv;
240 struct drm_device *dev = obj->dev;
241
242 return dev->driver->gem_prime_vmap(obj);
243}
244
245static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
246{
247 struct drm_gem_object *obj = dma_buf->priv;
248 struct drm_device *dev = obj->dev;
249
250 dev->driver->gem_prime_vunmap(obj, vaddr);
251}
252
253static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
254 unsigned long page_num)
255{
256 return NULL;
257}
258
259static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
260 unsigned long page_num, void *addr)
261{
262
263}
264static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
265 unsigned long page_num)
266{
267 return NULL;
268}
269
270static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
271 unsigned long page_num, void *addr)
272{
273
274}
275
276static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
277 struct vm_area_struct *vma)
278{
279 struct drm_gem_object *obj = dma_buf->priv;
280 struct drm_device *dev = obj->dev;
281
282 if (!dev->driver->gem_prime_mmap)
283 return -ENOSYS;
284
285 return dev->driver->gem_prime_mmap(obj, vma);
286}
287
288static 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,
301};
302
303/**
304 * DOC: PRIME Helpers
305 *
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:
310 *
311 * Export callbacks:
312 *
313 * - @gem_prime_pin (optional): prepare a GEM object for exporting
314 *
315 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
316 *
317 * - @gem_prime_vmap: vmap a buffer exported by your driver
318 *
319 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
320 *
321 * Import callback:
322 *
323 * - @gem_prime_import_sg_table (import): produce a GEM object from another
324 * driver's scatter/gather table
325 */
326
327/**
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
332 *
333 * This is the implementation of the gem_prime_export functions for GEM drivers
334 * using the PRIME helpers.
335 */
336struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
337 struct drm_gem_object *obj, int flags)
338{
339 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
340}
341EXPORT_SYMBOL(drm_gem_prime_export);
342
343static struct dma_buf *export_and_register_object(struct drm_device *dev,
344 struct drm_gem_object *obj,
345 uint32_t flags)
346{
347 struct dma_buf *dmabuf;
348
349 /* prevent races with concurrent gem_close. */
350 if (obj->handle_count == 0) {
351 dmabuf = ERR_PTR(-ENOENT);
352 return dmabuf;
353 }
354
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
359 */
360 return dmabuf;
361 }
362
363 /*
364 * Note that callers do not need to clean up the export cache
365 * since the check for obj->handle_count guarantees that someone
366 * will clean it up.
367 */
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);
372
373 return dmabuf;
374}
375
376/**
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
383 *
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.
388 */
389int drm_gem_prime_handle_to_fd(struct drm_device *dev,
390 struct drm_file *file_priv, uint32_t handle,
391 uint32_t flags,
392 int *prime_fd)
393{
394 struct drm_gem_object *obj;
395 int ret = 0;
396 struct dma_buf *dmabuf;
397
398 mutex_lock(&file_priv->prime.lock);
399 obj = drm_gem_object_lookup(dev, file_priv, handle);
400 if (!obj) {
401 ret = -ENOENT;
402 goto out_unlock;
403 }
404
405 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
406 if (dmabuf) {
407 get_dma_buf(dmabuf);
408 goto out_have_handle;
409 }
410
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;
415 get_dma_buf(dmabuf);
416 goto out_have_obj;
417 }
418
419 if (obj->dma_buf) {
420 get_dma_buf(obj->dma_buf);
421 dmabuf = obj->dma_buf;
422 goto out_have_obj;
423 }
424
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
429 */
430 ret = PTR_ERR(dmabuf);
431 mutex_unlock(&dev->object_name_lock);
432 goto out;
433 }
434
435out_have_obj:
436 /*
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.
441 */
442 ret = drm_prime_add_buf_handle(&file_priv->prime,
443 dmabuf, handle);
444 mutex_unlock(&dev->object_name_lock);
445 if (ret)
446 goto fail_put_dmabuf;
447
448out_have_handle:
449 ret = dma_buf_fd(dmabuf, flags);
450 /*
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.
455 */
456 if (ret < 0) {
457 goto fail_put_dmabuf;
458 } else {
459 *prime_fd = ret;
460 ret = 0;
461 }
462
463 goto out;
464
465fail_put_dmabuf:
466 dma_buf_put(dmabuf);
467out:
468 drm_gem_object_unreference_unlocked(obj);
469out_unlock:
470 mutex_unlock(&file_priv->prime.lock);
471
472 return ret;
473}
474EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
475
476/**
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
480 *
481 * This is the implementation of the gem_prime_import functions for GEM drivers
482 * using the PRIME helpers.
483 */
484struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
485 struct dma_buf *dma_buf)
486{
487 struct dma_buf_attachment *attach;
488 struct sg_table *sgt;
489 struct drm_gem_object *obj;
490 int ret;
491
492 if (!dev->driver->gem_prime_import_sg_table)
493 return ERR_PTR(-EINVAL);
494
495 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
496 obj = dma_buf->priv;
497 if (obj->dev == dev) {
498 /*
499 * Importing dmabuf exported from out own gem increases
500 * refcount on gem itself instead of f_count of dmabuf.
501 */
502 drm_gem_object_reference(obj);
503 return obj;
504 }
505 }
506
507 attach = dma_buf_attach(dma_buf, dev->dev);
508 if (IS_ERR(attach))
509 return ERR_CAST(attach);
510
511 get_dma_buf(dma_buf);
512
513 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
514 if (IS_ERR(sgt)) {
515 ret = PTR_ERR(sgt);
516 goto fail_detach;
517 }
518
519 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
520 if (IS_ERR(obj)) {
521 ret = PTR_ERR(obj);
522 goto fail_unmap;
523 }
524
525 obj->import_attach = attach;
526
527 return obj;
528
529fail_unmap:
530 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
531fail_detach:
532 dma_buf_detach(dma_buf, attach);
533 dma_buf_put(dma_buf);
534
535 return ERR_PTR(ret);
536}
537EXPORT_SYMBOL(drm_gem_prime_import);
538
539/**
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
545 *
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.
550 */
551int drm_gem_prime_fd_to_handle(struct drm_device *dev,
552 struct drm_file *file_priv, int prime_fd,
553 uint32_t *handle)
554{
555 struct dma_buf *dma_buf;
556 struct drm_gem_object *obj;
557 int ret;
558
559 dma_buf = dma_buf_get(prime_fd);
560 if (IS_ERR(dma_buf))
561 return PTR_ERR(dma_buf);
562
563 mutex_lock(&file_priv->prime.lock);
564
565 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
566 dma_buf, handle);
567 if (ret == 0)
568 goto out_put;
569
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);
573 if (IS_ERR(obj)) {
574 ret = PTR_ERR(obj);
575 goto out_unlock;
576 }
577
578 if (obj->dma_buf) {
579 WARN_ON(obj->dma_buf != dma_buf);
580 } else {
581 obj->dma_buf = dma_buf;
582 get_dma_buf(dma_buf);
583 }
584
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);
588 if (ret)
589 goto out_put;
590
591 ret = drm_prime_add_buf_handle(&file_priv->prime,
592 dma_buf, *handle);
593 if (ret)
594 goto fail;
595
596 mutex_unlock(&file_priv->prime.lock);
597
598 dma_buf_put(dma_buf);
599
600 return 0;
601
602fail:
603 /* hmm, if driver attached, we are relying on the free-object path
604 * to detach.. which seems ok..
605 */
606 drm_gem_handle_delete(file_priv, *handle);
607out_unlock:
608 mutex_unlock(&dev->object_name_lock);
609out_put:
610 dma_buf_put(dma_buf);
611 mutex_unlock(&file_priv->prime.lock);
612 return ret;
613}
614EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
615
616int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
617 struct drm_file *file_priv)
618{
619 struct drm_prime_handle *args = data;
620 uint32_t flags;
621
622 if (!drm_core_check_feature(dev, DRIVER_PRIME))
623 return -EINVAL;
624
625 if (!dev->driver->prime_handle_to_fd)
626 return -ENOSYS;
627
628 /* check flags are valid */
629 if (args->flags & ~DRM_CLOEXEC)
630 return -EINVAL;
631
632 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
633 flags = args->flags & DRM_CLOEXEC;
634
635 return dev->driver->prime_handle_to_fd(dev, file_priv,
636 args->handle, flags, &args->fd);
637}
638
639int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
640 struct drm_file *file_priv)
641{
642 struct drm_prime_handle *args = data;
643
644 if (!drm_core_check_feature(dev, DRIVER_PRIME))
645 return -EINVAL;
646
647 if (!dev->driver->prime_fd_to_handle)
648 return -ENOSYS;
649
650 return dev->driver->prime_fd_to_handle(dev, file_priv,
651 args->fd, &args->handle);
652}
653
654/**
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
658 *
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.
662 */
663struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
664{
665 struct sg_table *sg = NULL;
666 int ret;
667
668 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
669 if (!sg) {
670 ret = -ENOMEM;
671 goto out;
672 }
673
674 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
675 nr_pages << PAGE_SHIFT, GFP_KERNEL);
676 if (ret)
677 goto out;
678
679 return sg;
680out:
681 kfree(sg);
682 return ERR_PTR(ret);
683}
684EXPORT_SYMBOL(drm_prime_pages_to_sg);
685
686/**
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
692 *
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.
695 */
696int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
697 dma_addr_t *addrs, int max_pages)
698{
699 unsigned count;
700 struct scatterlist *sg;
701 struct page *page;
702 u32 len;
703 int pg_index;
704 dma_addr_t addr;
705
706 pg_index = 0;
707 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
708 len = sg->length;
709 page = sg_page(sg);
710 addr = sg_dma_address(sg);
711
712 while (len > 0) {
713 if (WARN_ON(pg_index >= max_pages))
714 return -1;
715 pages[pg_index] = page;
716 if (addrs)
717 addrs[pg_index] = addr;
718
719 page++;
720 addr += PAGE_SIZE;
721 len -= PAGE_SIZE;
722 pg_index++;
723 }
724 }
725 return 0;
726}
727EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
728
729/**
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
733 *
734 * This is the cleanup functions which GEM drivers need to call when they use
735 * @drm_gem_prime_import to import dma-bufs.
736 */
737void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
738{
739 struct dma_buf_attachment *attach;
740 struct dma_buf *dma_buf;
741 attach = obj->import_attach;
742 if (sg)
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);
748}
749EXPORT_SYMBOL(drm_prime_gem_destroy);
750
751void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
752{
753 INIT_LIST_HEAD(&prime_fpriv->head);
754 mutex_init(&prime_fpriv->lock);
755}
756
757void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
758{
759 /* by now drm_gem_release should've made sure the list is empty */
760 WARN_ON(!list_empty(&prime_fpriv->head));
761}