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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 <linux/rbtree.h>
32#include <linux/module.h>
33
34#include <drm/drm.h>
35#include <drm/drm_drv.h>
36#include <drm/drm_file.h>
37#include <drm/drm_framebuffer.h>
38#include <drm/drm_gem.h>
39#include <drm/drm_prime.h>
40
41#include "drm_internal.h"
42
43MODULE_IMPORT_NS(DMA_BUF);
44
45/**
46 * DOC: overview and lifetime rules
47 *
48 * Similar to GEM global names, PRIME file descriptors are also used to share
49 * buffer objects across processes. They offer additional security: as file
50 * descriptors must be explicitly sent over UNIX domain sockets to be shared
51 * between applications, they can't be guessed like the globally unique GEM
52 * names.
53 *
54 * Drivers that support the PRIME API implement the drm_gem_object_funcs.export
55 * and &drm_driver.gem_prime_import hooks. &dma_buf_ops implementations for
56 * drivers are all individually exported for drivers which need to overwrite
57 * or reimplement some of them.
58 *
59 * Reference Counting for GEM Drivers
60 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
61 *
62 * On the export the &dma_buf holds a reference to the exported buffer object,
63 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
64 * IOCTL, when it first calls &drm_gem_object_funcs.export
65 * and stores the exporting GEM object in the &dma_buf.priv field. This
66 * reference needs to be released when the final reference to the &dma_buf
67 * itself is dropped and its &dma_buf_ops.release function is called. For
68 * GEM-based drivers, the &dma_buf should be exported using
69 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
70 *
71 * Thus the chain of references always flows in one direction, avoiding loops:
72 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
73 * are the lookup caches for import and export. These are required to guarantee
74 * that any given object will always have only one unique userspace handle. This
75 * is required to allow userspace to detect duplicated imports, since some GEM
76 * drivers do fail command submissions if a given buffer object is listed more
77 * than once. These import and export caches in &drm_prime_file_private only
78 * retain a weak reference, which is cleaned up when the corresponding object is
79 * released.
80 *
81 * Self-importing: If userspace is using PRIME as a replacement for flink then
82 * it will get a fd->handle request for a GEM object that it created. Drivers
83 * should detect this situation and return back the underlying object from the
84 * dma-buf private. For GEM based drivers this is handled in
85 * drm_gem_prime_import() already.
86 */
87
88struct drm_prime_member {
89 struct dma_buf *dma_buf;
90 uint32_t handle;
91
92 struct rb_node dmabuf_rb;
93 struct rb_node handle_rb;
94};
95
96static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
97 struct dma_buf *dma_buf, uint32_t handle)
98{
99 struct drm_prime_member *member;
100 struct rb_node **p, *rb;
101
102 member = kmalloc(sizeof(*member), GFP_KERNEL);
103 if (!member)
104 return -ENOMEM;
105
106 get_dma_buf(dma_buf);
107 member->dma_buf = dma_buf;
108 member->handle = handle;
109
110 rb = NULL;
111 p = &prime_fpriv->dmabufs.rb_node;
112 while (*p) {
113 struct drm_prime_member *pos;
114
115 rb = *p;
116 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
117 if (dma_buf > pos->dma_buf)
118 p = &rb->rb_right;
119 else
120 p = &rb->rb_left;
121 }
122 rb_link_node(&member->dmabuf_rb, rb, p);
123 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
124
125 rb = NULL;
126 p = &prime_fpriv->handles.rb_node;
127 while (*p) {
128 struct drm_prime_member *pos;
129
130 rb = *p;
131 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
132 if (handle > pos->handle)
133 p = &rb->rb_right;
134 else
135 p = &rb->rb_left;
136 }
137 rb_link_node(&member->handle_rb, rb, p);
138 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
139
140 return 0;
141}
142
143static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
144 uint32_t handle)
145{
146 struct rb_node *rb;
147
148 rb = prime_fpriv->handles.rb_node;
149 while (rb) {
150 struct drm_prime_member *member;
151
152 member = rb_entry(rb, struct drm_prime_member, handle_rb);
153 if (member->handle == handle)
154 return member->dma_buf;
155 else if (member->handle < handle)
156 rb = rb->rb_right;
157 else
158 rb = rb->rb_left;
159 }
160
161 return NULL;
162}
163
164static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
165 struct dma_buf *dma_buf,
166 uint32_t *handle)
167{
168 struct rb_node *rb;
169
170 rb = prime_fpriv->dmabufs.rb_node;
171 while (rb) {
172 struct drm_prime_member *member;
173
174 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
175 if (member->dma_buf == dma_buf) {
176 *handle = member->handle;
177 return 0;
178 } else if (member->dma_buf < dma_buf) {
179 rb = rb->rb_right;
180 } else {
181 rb = rb->rb_left;
182 }
183 }
184
185 return -ENOENT;
186}
187
188void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
189 uint32_t handle)
190{
191 struct rb_node *rb;
192
193 mutex_lock(&prime_fpriv->lock);
194
195 rb = prime_fpriv->handles.rb_node;
196 while (rb) {
197 struct drm_prime_member *member;
198
199 member = rb_entry(rb, struct drm_prime_member, handle_rb);
200 if (member->handle == handle) {
201 rb_erase(&member->handle_rb, &prime_fpriv->handles);
202 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
203
204 dma_buf_put(member->dma_buf);
205 kfree(member);
206 break;
207 } else if (member->handle < handle) {
208 rb = rb->rb_right;
209 } else {
210 rb = rb->rb_left;
211 }
212 }
213
214 mutex_unlock(&prime_fpriv->lock);
215}
216
217void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
218{
219 mutex_init(&prime_fpriv->lock);
220 prime_fpriv->dmabufs = RB_ROOT;
221 prime_fpriv->handles = RB_ROOT;
222}
223
224void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
225{
226 /* by now drm_gem_release should've made sure the list is empty */
227 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
228}
229
230/**
231 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
232 * @dev: parent device for the exported dmabuf
233 * @exp_info: the export information used by dma_buf_export()
234 *
235 * This wraps dma_buf_export() for use by generic GEM drivers that are using
236 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
237 * a reference to the &drm_device and the exported &drm_gem_object (stored in
238 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
239 *
240 * Returns the new dmabuf.
241 */
242struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
243 struct dma_buf_export_info *exp_info)
244{
245 struct drm_gem_object *obj = exp_info->priv;
246 struct dma_buf *dma_buf;
247
248 dma_buf = dma_buf_export(exp_info);
249 if (IS_ERR(dma_buf))
250 return dma_buf;
251
252 drm_dev_get(dev);
253 drm_gem_object_get(obj);
254 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
255
256 return dma_buf;
257}
258EXPORT_SYMBOL(drm_gem_dmabuf_export);
259
260/**
261 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
262 * @dma_buf: buffer to be released
263 *
264 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
265 * must use this in their &dma_buf_ops structure as the release callback.
266 * drm_gem_dmabuf_release() should be used in conjunction with
267 * drm_gem_dmabuf_export().
268 */
269void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
270{
271 struct drm_gem_object *obj = dma_buf->priv;
272 struct drm_device *dev = obj->dev;
273
274 /* drop the reference on the export fd holds */
275 drm_gem_object_put(obj);
276
277 drm_dev_put(dev);
278}
279EXPORT_SYMBOL(drm_gem_dmabuf_release);
280
281/**
282 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
283 * @dev: drm_device to import into
284 * @file_priv: drm file-private structure
285 * @prime_fd: fd id of the dma-buf which should be imported
286 * @handle: pointer to storage for the handle of the imported buffer object
287 *
288 * This is the PRIME import function which must be used mandatorily by GEM
289 * drivers to ensure correct lifetime management of the underlying GEM object.
290 * The actual importing of GEM object from the dma-buf is done through the
291 * &drm_driver.gem_prime_import driver callback.
292 *
293 * Returns 0 on success or a negative error code on failure.
294 */
295int drm_gem_prime_fd_to_handle(struct drm_device *dev,
296 struct drm_file *file_priv, int prime_fd,
297 uint32_t *handle)
298{
299 struct dma_buf *dma_buf;
300 struct drm_gem_object *obj;
301 int ret;
302
303 dma_buf = dma_buf_get(prime_fd);
304 if (IS_ERR(dma_buf))
305 return PTR_ERR(dma_buf);
306
307 mutex_lock(&file_priv->prime.lock);
308
309 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
310 dma_buf, handle);
311 if (ret == 0)
312 goto out_put;
313
314 /* never seen this one, need to import */
315 mutex_lock(&dev->object_name_lock);
316 if (dev->driver->gem_prime_import)
317 obj = dev->driver->gem_prime_import(dev, dma_buf);
318 else
319 obj = drm_gem_prime_import(dev, dma_buf);
320 if (IS_ERR(obj)) {
321 ret = PTR_ERR(obj);
322 goto out_unlock;
323 }
324
325 if (obj->dma_buf) {
326 WARN_ON(obj->dma_buf != dma_buf);
327 } else {
328 obj->dma_buf = dma_buf;
329 get_dma_buf(dma_buf);
330 }
331
332 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
333 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
334 drm_gem_object_put(obj);
335 if (ret)
336 goto out_put;
337
338 ret = drm_prime_add_buf_handle(&file_priv->prime,
339 dma_buf, *handle);
340 mutex_unlock(&file_priv->prime.lock);
341 if (ret)
342 goto fail;
343
344 dma_buf_put(dma_buf);
345
346 return 0;
347
348fail:
349 /* hmm, if driver attached, we are relying on the free-object path
350 * to detach.. which seems ok..
351 */
352 drm_gem_handle_delete(file_priv, *handle);
353 dma_buf_put(dma_buf);
354 return ret;
355
356out_unlock:
357 mutex_unlock(&dev->object_name_lock);
358out_put:
359 mutex_unlock(&file_priv->prime.lock);
360 dma_buf_put(dma_buf);
361 return ret;
362}
363EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
364
365int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
366 struct drm_file *file_priv)
367{
368 struct drm_prime_handle *args = data;
369
370 if (dev->driver->prime_fd_to_handle) {
371 return dev->driver->prime_fd_to_handle(dev, file_priv, args->fd,
372 &args->handle);
373 }
374
375 return drm_gem_prime_fd_to_handle(dev, file_priv, args->fd, &args->handle);
376}
377
378static struct dma_buf *export_and_register_object(struct drm_device *dev,
379 struct drm_gem_object *obj,
380 uint32_t flags)
381{
382 struct dma_buf *dmabuf;
383
384 /* prevent races with concurrent gem_close. */
385 if (obj->handle_count == 0) {
386 dmabuf = ERR_PTR(-ENOENT);
387 return dmabuf;
388 }
389
390 if (obj->funcs && obj->funcs->export)
391 dmabuf = obj->funcs->export(obj, flags);
392 else
393 dmabuf = drm_gem_prime_export(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
397 */
398 return dmabuf;
399 }
400
401 /*
402 * Note that callers do not need to clean up the export cache
403 * since the check for obj->handle_count guarantees that someone
404 * will clean it up.
405 */
406 obj->dma_buf = dmabuf;
407 get_dma_buf(obj->dma_buf);
408
409 return dmabuf;
410}
411
412/**
413 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
414 * @dev: dev to export the buffer from
415 * @file_priv: drm file-private structure
416 * @handle: buffer handle to export
417 * @flags: flags like DRM_CLOEXEC
418 * @prime_fd: pointer to storage for the fd id of the create dma-buf
419 *
420 * This is the PRIME export function which must be used mandatorily by GEM
421 * drivers to ensure correct lifetime management of the underlying GEM object.
422 * The actual exporting from GEM object to a dma-buf is done through the
423 * &drm_gem_object_funcs.export callback.
424 */
425int drm_gem_prime_handle_to_fd(struct drm_device *dev,
426 struct drm_file *file_priv, uint32_t handle,
427 uint32_t flags,
428 int *prime_fd)
429{
430 struct drm_gem_object *obj;
431 int ret = 0;
432 struct dma_buf *dmabuf;
433
434 mutex_lock(&file_priv->prime.lock);
435 obj = drm_gem_object_lookup(file_priv, handle);
436 if (!obj) {
437 ret = -ENOENT;
438 goto out_unlock;
439 }
440
441 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
442 if (dmabuf) {
443 get_dma_buf(dmabuf);
444 goto out_have_handle;
445 }
446
447 mutex_lock(&dev->object_name_lock);
448 /* re-export the original imported object */
449 if (obj->import_attach) {
450 dmabuf = obj->import_attach->dmabuf;
451 get_dma_buf(dmabuf);
452 goto out_have_obj;
453 }
454
455 if (obj->dma_buf) {
456 get_dma_buf(obj->dma_buf);
457 dmabuf = obj->dma_buf;
458 goto out_have_obj;
459 }
460
461 dmabuf = export_and_register_object(dev, obj, flags);
462 if (IS_ERR(dmabuf)) {
463 /* normally the created dma-buf takes ownership of the ref,
464 * but if that fails then drop the ref
465 */
466 ret = PTR_ERR(dmabuf);
467 mutex_unlock(&dev->object_name_lock);
468 goto out;
469 }
470
471out_have_obj:
472 /*
473 * If we've exported this buffer then cheat and add it to the import list
474 * so we get the correct handle back. We must do this under the
475 * protection of dev->object_name_lock to ensure that a racing gem close
476 * ioctl doesn't miss to remove this buffer handle from the cache.
477 */
478 ret = drm_prime_add_buf_handle(&file_priv->prime,
479 dmabuf, handle);
480 mutex_unlock(&dev->object_name_lock);
481 if (ret)
482 goto fail_put_dmabuf;
483
484out_have_handle:
485 ret = dma_buf_fd(dmabuf, flags);
486 /*
487 * We must _not_ remove the buffer from the handle cache since the newly
488 * created dma buf is already linked in the global obj->dma_buf pointer,
489 * and that is invariant as long as a userspace gem handle exists.
490 * Closing the handle will clean out the cache anyway, so we don't leak.
491 */
492 if (ret < 0) {
493 goto fail_put_dmabuf;
494 } else {
495 *prime_fd = ret;
496 ret = 0;
497 }
498
499 goto out;
500
501fail_put_dmabuf:
502 dma_buf_put(dmabuf);
503out:
504 drm_gem_object_put(obj);
505out_unlock:
506 mutex_unlock(&file_priv->prime.lock);
507
508 return ret;
509}
510EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
511
512int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
513 struct drm_file *file_priv)
514{
515 struct drm_prime_handle *args = data;
516
517 /* check flags are valid */
518 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
519 return -EINVAL;
520
521 if (dev->driver->prime_handle_to_fd) {
522 return dev->driver->prime_handle_to_fd(dev, file_priv,
523 args->handle, args->flags,
524 &args->fd);
525 }
526 return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
527 args->flags, &args->fd);
528}
529
530/**
531 * DOC: PRIME Helpers
532 *
533 * Drivers can implement &drm_gem_object_funcs.export and
534 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
535 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
536 * implement dma-buf support in terms of some lower-level helpers, which are
537 * again exported for drivers to use individually:
538 *
539 * Exporting buffers
540 * ~~~~~~~~~~~~~~~~~
541 *
542 * Optional pinning of buffers is handled at dma-buf attach and detach time in
543 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
544 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
545 * &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is
546 * unimplemented, exports into another device are rejected.
547 *
548 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
549 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
550 * drm_gem_dmabuf_mmap().
551 *
552 * Note that these export helpers can only be used if the underlying backing
553 * storage is fully coherent and either permanently pinned, or it is safe to pin
554 * it indefinitely.
555 *
556 * FIXME: The underlying helper functions are named rather inconsistently.
557 *
558 * Importing buffers
559 * ~~~~~~~~~~~~~~~~~
560 *
561 * Importing dma-bufs using drm_gem_prime_import() relies on
562 * &drm_driver.gem_prime_import_sg_table.
563 *
564 * Note that similarly to the export helpers this permanently pins the
565 * underlying backing storage. Which is ok for scanout, but is not the best
566 * option for sharing lots of buffers for rendering.
567 */
568
569/**
570 * drm_gem_map_attach - dma_buf attach implementation for GEM
571 * @dma_buf: buffer to attach device to
572 * @attach: buffer attachment data
573 *
574 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
575 * used as the &dma_buf_ops.attach callback. Must be used together with
576 * drm_gem_map_detach().
577 *
578 * Returns 0 on success, negative error code on failure.
579 */
580int drm_gem_map_attach(struct dma_buf *dma_buf,
581 struct dma_buf_attachment *attach)
582{
583 struct drm_gem_object *obj = dma_buf->priv;
584
585 if (!obj->funcs->get_sg_table)
586 return -ENOSYS;
587
588 return drm_gem_pin(obj);
589}
590EXPORT_SYMBOL(drm_gem_map_attach);
591
592/**
593 * drm_gem_map_detach - dma_buf detach implementation for GEM
594 * @dma_buf: buffer to detach from
595 * @attach: attachment to be detached
596 *
597 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
598 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
599 * &dma_buf_ops.detach callback.
600 */
601void drm_gem_map_detach(struct dma_buf *dma_buf,
602 struct dma_buf_attachment *attach)
603{
604 struct drm_gem_object *obj = dma_buf->priv;
605
606 drm_gem_unpin(obj);
607}
608EXPORT_SYMBOL(drm_gem_map_detach);
609
610/**
611 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
612 * @attach: attachment whose scatterlist is to be returned
613 * @dir: direction of DMA transfer
614 *
615 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
616 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
617 * with drm_gem_unmap_dma_buf().
618 *
619 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
620 * on error. May return -EINTR if it is interrupted by a signal.
621 */
622struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
623 enum dma_data_direction dir)
624{
625 struct drm_gem_object *obj = attach->dmabuf->priv;
626 struct sg_table *sgt;
627 int ret;
628
629 if (WARN_ON(dir == DMA_NONE))
630 return ERR_PTR(-EINVAL);
631
632 if (WARN_ON(!obj->funcs->get_sg_table))
633 return ERR_PTR(-ENOSYS);
634
635 sgt = obj->funcs->get_sg_table(obj);
636 if (IS_ERR(sgt))
637 return sgt;
638
639 ret = dma_map_sgtable(attach->dev, sgt, dir,
640 DMA_ATTR_SKIP_CPU_SYNC);
641 if (ret) {
642 sg_free_table(sgt);
643 kfree(sgt);
644 sgt = ERR_PTR(ret);
645 }
646
647 return sgt;
648}
649EXPORT_SYMBOL(drm_gem_map_dma_buf);
650
651/**
652 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
653 * @attach: attachment to unmap buffer from
654 * @sgt: scatterlist info of the buffer to unmap
655 * @dir: direction of DMA transfer
656 *
657 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
658 */
659void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
660 struct sg_table *sgt,
661 enum dma_data_direction dir)
662{
663 if (!sgt)
664 return;
665
666 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
667 sg_free_table(sgt);
668 kfree(sgt);
669}
670EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
671
672/**
673 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
674 * @dma_buf: buffer to be mapped
675 * @map: the virtual address of the buffer
676 *
677 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
678 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
679 * The kernel virtual address is returned in map.
680 *
681 * Returns 0 on success or a negative errno code otherwise.
682 */
683int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
684{
685 struct drm_gem_object *obj = dma_buf->priv;
686
687 return drm_gem_vmap(obj, map);
688}
689EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
690
691/**
692 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
693 * @dma_buf: buffer to be unmapped
694 * @map: the virtual address of the buffer
695 *
696 * Releases a kernel virtual mapping. This can be used as the
697 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
698 */
699void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
700{
701 struct drm_gem_object *obj = dma_buf->priv;
702
703 drm_gem_vunmap(obj, map);
704}
705EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
706
707/**
708 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
709 * @obj: GEM object
710 * @vma: Virtual address range
711 *
712 * This function sets up a userspace mapping for PRIME exported buffers using
713 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
714 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
715 * called to set up the mapping.
716 */
717int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
718{
719 struct drm_file *priv;
720 struct file *fil;
721 int ret;
722
723 /* Add the fake offset */
724 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
725
726 if (obj->funcs && obj->funcs->mmap) {
727 vma->vm_ops = obj->funcs->vm_ops;
728
729 drm_gem_object_get(obj);
730 ret = obj->funcs->mmap(obj, vma);
731 if (ret) {
732 drm_gem_object_put(obj);
733 return ret;
734 }
735 vma->vm_private_data = obj;
736 return 0;
737 }
738
739 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
740 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
741 if (!priv || !fil) {
742 ret = -ENOMEM;
743 goto out;
744 }
745
746 /* Used by drm_gem_mmap() to lookup the GEM object */
747 priv->minor = obj->dev->primary;
748 fil->private_data = priv;
749
750 ret = drm_vma_node_allow(&obj->vma_node, priv);
751 if (ret)
752 goto out;
753
754 ret = obj->dev->driver->fops->mmap(fil, vma);
755
756 drm_vma_node_revoke(&obj->vma_node, priv);
757out:
758 kfree(priv);
759 kfree(fil);
760
761 return ret;
762}
763EXPORT_SYMBOL(drm_gem_prime_mmap);
764
765/**
766 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
767 * @dma_buf: buffer to be mapped
768 * @vma: virtual address range
769 *
770 * Provides memory mapping for the buffer. This can be used as the
771 * &dma_buf_ops.mmap callback. It just forwards to drm_gem_prime_mmap().
772 *
773 * Returns 0 on success or a negative error code on failure.
774 */
775int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
776{
777 struct drm_gem_object *obj = dma_buf->priv;
778
779 return drm_gem_prime_mmap(obj, vma);
780}
781EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
782
783static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
784 .cache_sgt_mapping = true,
785 .attach = drm_gem_map_attach,
786 .detach = drm_gem_map_detach,
787 .map_dma_buf = drm_gem_map_dma_buf,
788 .unmap_dma_buf = drm_gem_unmap_dma_buf,
789 .release = drm_gem_dmabuf_release,
790 .mmap = drm_gem_dmabuf_mmap,
791 .vmap = drm_gem_dmabuf_vmap,
792 .vunmap = drm_gem_dmabuf_vunmap,
793};
794
795/**
796 * drm_prime_pages_to_sg - converts a page array into an sg list
797 * @dev: DRM device
798 * @pages: pointer to the array of page pointers to convert
799 * @nr_pages: length of the page vector
800 *
801 * This helper creates an sg table object from a set of pages
802 * the driver is responsible for mapping the pages into the
803 * importers address space for use with dma_buf itself.
804 *
805 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
806 */
807struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
808 struct page **pages, unsigned int nr_pages)
809{
810 struct sg_table *sg;
811 size_t max_segment = 0;
812 int err;
813
814 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
815 if (!sg)
816 return ERR_PTR(-ENOMEM);
817
818 if (dev)
819 max_segment = dma_max_mapping_size(dev->dev);
820 if (max_segment == 0)
821 max_segment = UINT_MAX;
822 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
823 (unsigned long)nr_pages << PAGE_SHIFT,
824 max_segment, GFP_KERNEL);
825 if (err) {
826 kfree(sg);
827 sg = ERR_PTR(err);
828 }
829 return sg;
830}
831EXPORT_SYMBOL(drm_prime_pages_to_sg);
832
833/**
834 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
835 * @sgt: sg_table describing the buffer to check
836 *
837 * This helper calculates the contiguous size in the DMA address space
838 * of the buffer described by the provided sg_table.
839 *
840 * This is useful for implementing
841 * &drm_gem_object_funcs.gem_prime_import_sg_table.
842 */
843unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
844{
845 dma_addr_t expected = sg_dma_address(sgt->sgl);
846 struct scatterlist *sg;
847 unsigned long size = 0;
848 int i;
849
850 for_each_sgtable_dma_sg(sgt, sg, i) {
851 unsigned int len = sg_dma_len(sg);
852
853 if (!len)
854 break;
855 if (sg_dma_address(sg) != expected)
856 break;
857 expected += len;
858 size += len;
859 }
860 return size;
861}
862EXPORT_SYMBOL(drm_prime_get_contiguous_size);
863
864/**
865 * drm_gem_prime_export - helper library implementation of the export callback
866 * @obj: GEM object to export
867 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
868 *
869 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
870 * using the PRIME helpers. It is used as the default in
871 * drm_gem_prime_handle_to_fd().
872 */
873struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
874 int flags)
875{
876 struct drm_device *dev = obj->dev;
877 struct dma_buf_export_info exp_info = {
878 .exp_name = KBUILD_MODNAME, /* white lie for debug */
879 .owner = dev->driver->fops->owner,
880 .ops = &drm_gem_prime_dmabuf_ops,
881 .size = obj->size,
882 .flags = flags,
883 .priv = obj,
884 .resv = obj->resv,
885 };
886
887 return drm_gem_dmabuf_export(dev, &exp_info);
888}
889EXPORT_SYMBOL(drm_gem_prime_export);
890
891/**
892 * drm_gem_prime_import_dev - core implementation of the import callback
893 * @dev: drm_device to import into
894 * @dma_buf: dma-buf object to import
895 * @attach_dev: struct device to dma_buf attach
896 *
897 * This is the core of drm_gem_prime_import(). It's designed to be called by
898 * drivers who want to use a different device structure than &drm_device.dev for
899 * attaching via dma_buf. This function calls
900 * &drm_driver.gem_prime_import_sg_table internally.
901 *
902 * Drivers must arrange to call drm_prime_gem_destroy() from their
903 * &drm_gem_object_funcs.free hook when using this function.
904 */
905struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
906 struct dma_buf *dma_buf,
907 struct device *attach_dev)
908{
909 struct dma_buf_attachment *attach;
910 struct sg_table *sgt;
911 struct drm_gem_object *obj;
912 int ret;
913
914 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
915 obj = dma_buf->priv;
916 if (obj->dev == dev) {
917 /*
918 * Importing dmabuf exported from our own gem increases
919 * refcount on gem itself instead of f_count of dmabuf.
920 */
921 drm_gem_object_get(obj);
922 return obj;
923 }
924 }
925
926 if (!dev->driver->gem_prime_import_sg_table)
927 return ERR_PTR(-EINVAL);
928
929 attach = dma_buf_attach(dma_buf, attach_dev);
930 if (IS_ERR(attach))
931 return ERR_CAST(attach);
932
933 get_dma_buf(dma_buf);
934
935 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
936 if (IS_ERR(sgt)) {
937 ret = PTR_ERR(sgt);
938 goto fail_detach;
939 }
940
941 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
942 if (IS_ERR(obj)) {
943 ret = PTR_ERR(obj);
944 goto fail_unmap;
945 }
946
947 obj->import_attach = attach;
948 obj->resv = dma_buf->resv;
949
950 return obj;
951
952fail_unmap:
953 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
954fail_detach:
955 dma_buf_detach(dma_buf, attach);
956 dma_buf_put(dma_buf);
957
958 return ERR_PTR(ret);
959}
960EXPORT_SYMBOL(drm_gem_prime_import_dev);
961
962/**
963 * drm_gem_prime_import - helper library implementation of the import callback
964 * @dev: drm_device to import into
965 * @dma_buf: dma-buf object to import
966 *
967 * This is the implementation of the gem_prime_import functions for GEM drivers
968 * using the PRIME helpers. Drivers can use this as their
969 * &drm_driver.gem_prime_import implementation. It is used as the default
970 * implementation in drm_gem_prime_fd_to_handle().
971 *
972 * Drivers must arrange to call drm_prime_gem_destroy() from their
973 * &drm_gem_object_funcs.free hook when using this function.
974 */
975struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
976 struct dma_buf *dma_buf)
977{
978 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
979}
980EXPORT_SYMBOL(drm_gem_prime_import);
981
982/**
983 * drm_prime_sg_to_page_array - convert an sg table into a page array
984 * @sgt: scatter-gather table to convert
985 * @pages: array of page pointers to store the pages in
986 * @max_entries: size of the passed-in array
987 *
988 * Exports an sg table into an array of pages.
989 *
990 * This function is deprecated and strongly discouraged to be used.
991 * The page array is only useful for page faults and those can corrupt fields
992 * in the struct page if they are not handled by the exporting driver.
993 */
994int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
995 struct page **pages,
996 int max_entries)
997{
998 struct sg_page_iter page_iter;
999 struct page **p = pages;
1000
1001 for_each_sgtable_page(sgt, &page_iter, 0) {
1002 if (WARN_ON(p - pages >= max_entries))
1003 return -1;
1004 *p++ = sg_page_iter_page(&page_iter);
1005 }
1006 return 0;
1007}
1008EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1009
1010/**
1011 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1012 * @sgt: scatter-gather table to convert
1013 * @addrs: array to store the dma bus address of each page
1014 * @max_entries: size of both the passed-in arrays
1015 *
1016 * Exports an sg table into an array of addresses.
1017 *
1018 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1019 * implementation.
1020 */
1021int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1022 int max_entries)
1023{
1024 struct sg_dma_page_iter dma_iter;
1025 dma_addr_t *a = addrs;
1026
1027 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1028 if (WARN_ON(a - addrs >= max_entries))
1029 return -1;
1030 *a++ = sg_page_iter_dma_address(&dma_iter);
1031 }
1032 return 0;
1033}
1034EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1035
1036/**
1037 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1038 * @obj: GEM object which was created from a dma-buf
1039 * @sg: the sg-table which was pinned at import time
1040 *
1041 * This is the cleanup functions which GEM drivers need to call when they use
1042 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1043 */
1044void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1045{
1046 struct dma_buf_attachment *attach;
1047 struct dma_buf *dma_buf;
1048
1049 attach = obj->import_attach;
1050 if (sg)
1051 dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
1052 dma_buf = attach->dmabuf;
1053 dma_buf_detach(attach->dmabuf, attach);
1054 /* remove the reference */
1055 dma_buf_put(dma_buf);
1056}
1057EXPORT_SYMBOL(drm_prime_gem_destroy);
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 <linux/rbtree.h>
32#include <linux/module.h>
33
34#include <drm/drm.h>
35#include <drm/drm_drv.h>
36#include <drm/drm_file.h>
37#include <drm/drm_framebuffer.h>
38#include <drm/drm_gem.h>
39#include <drm/drm_prime.h>
40
41#include "drm_internal.h"
42
43MODULE_IMPORT_NS(DMA_BUF);
44
45/**
46 * DOC: overview and lifetime rules
47 *
48 * Similar to GEM global names, PRIME file descriptors are also used to share
49 * buffer objects across processes. They offer additional security: as file
50 * descriptors must be explicitly sent over UNIX domain sockets to be shared
51 * between applications, they can't be guessed like the globally unique GEM
52 * names.
53 *
54 * Drivers that support the PRIME API implement the
55 * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
56 * GEM based drivers must use drm_gem_prime_handle_to_fd() and
57 * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
58 * actual driver interfaces is provided through the &drm_gem_object_funcs.export
59 * and &drm_driver.gem_prime_import hooks.
60 *
61 * &dma_buf_ops implementations for GEM drivers are all individually exported
62 * for drivers which need to overwrite or reimplement some of them.
63 *
64 * Reference Counting for GEM Drivers
65 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
66 *
67 * On the export the &dma_buf holds a reference to the exported buffer object,
68 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
69 * IOCTL, when it first calls &drm_gem_object_funcs.export
70 * and stores the exporting GEM object in the &dma_buf.priv field. This
71 * reference needs to be released when the final reference to the &dma_buf
72 * itself is dropped and its &dma_buf_ops.release function is called. For
73 * GEM-based drivers, the &dma_buf should be exported using
74 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
75 *
76 * Thus the chain of references always flows in one direction, avoiding loops:
77 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
78 * are the lookup caches for import and export. These are required to guarantee
79 * that any given object will always have only one unique userspace handle. This
80 * is required to allow userspace to detect duplicated imports, since some GEM
81 * drivers do fail command submissions if a given buffer object is listed more
82 * than once. These import and export caches in &drm_prime_file_private only
83 * retain a weak reference, which is cleaned up when the corresponding object is
84 * released.
85 *
86 * Self-importing: If userspace is using PRIME as a replacement for flink then
87 * it will get a fd->handle request for a GEM object that it created. Drivers
88 * should detect this situation and return back the underlying object from the
89 * dma-buf private. For GEM based drivers this is handled in
90 * drm_gem_prime_import() already.
91 */
92
93struct drm_prime_member {
94 struct dma_buf *dma_buf;
95 uint32_t handle;
96
97 struct rb_node dmabuf_rb;
98 struct rb_node handle_rb;
99};
100
101static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
102 struct dma_buf *dma_buf, uint32_t handle)
103{
104 struct drm_prime_member *member;
105 struct rb_node **p, *rb;
106
107 member = kmalloc(sizeof(*member), GFP_KERNEL);
108 if (!member)
109 return -ENOMEM;
110
111 get_dma_buf(dma_buf);
112 member->dma_buf = dma_buf;
113 member->handle = handle;
114
115 rb = NULL;
116 p = &prime_fpriv->dmabufs.rb_node;
117 while (*p) {
118 struct drm_prime_member *pos;
119
120 rb = *p;
121 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
122 if (dma_buf > pos->dma_buf)
123 p = &rb->rb_right;
124 else
125 p = &rb->rb_left;
126 }
127 rb_link_node(&member->dmabuf_rb, rb, p);
128 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
129
130 rb = NULL;
131 p = &prime_fpriv->handles.rb_node;
132 while (*p) {
133 struct drm_prime_member *pos;
134
135 rb = *p;
136 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
137 if (handle > pos->handle)
138 p = &rb->rb_right;
139 else
140 p = &rb->rb_left;
141 }
142 rb_link_node(&member->handle_rb, rb, p);
143 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
144
145 return 0;
146}
147
148static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
149 uint32_t handle)
150{
151 struct rb_node *rb;
152
153 rb = prime_fpriv->handles.rb_node;
154 while (rb) {
155 struct drm_prime_member *member;
156
157 member = rb_entry(rb, struct drm_prime_member, handle_rb);
158 if (member->handle == handle)
159 return member->dma_buf;
160 else if (member->handle < handle)
161 rb = rb->rb_right;
162 else
163 rb = rb->rb_left;
164 }
165
166 return NULL;
167}
168
169static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
170 struct dma_buf *dma_buf,
171 uint32_t *handle)
172{
173 struct rb_node *rb;
174
175 rb = prime_fpriv->dmabufs.rb_node;
176 while (rb) {
177 struct drm_prime_member *member;
178
179 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
180 if (member->dma_buf == dma_buf) {
181 *handle = member->handle;
182 return 0;
183 } else if (member->dma_buf < dma_buf) {
184 rb = rb->rb_right;
185 } else {
186 rb = rb->rb_left;
187 }
188 }
189
190 return -ENOENT;
191}
192
193void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
194 uint32_t handle)
195{
196 struct rb_node *rb;
197
198 mutex_lock(&prime_fpriv->lock);
199
200 rb = prime_fpriv->handles.rb_node;
201 while (rb) {
202 struct drm_prime_member *member;
203
204 member = rb_entry(rb, struct drm_prime_member, handle_rb);
205 if (member->handle == handle) {
206 rb_erase(&member->handle_rb, &prime_fpriv->handles);
207 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
208
209 dma_buf_put(member->dma_buf);
210 kfree(member);
211 break;
212 } else if (member->handle < handle) {
213 rb = rb->rb_right;
214 } else {
215 rb = rb->rb_left;
216 }
217 }
218
219 mutex_unlock(&prime_fpriv->lock);
220}
221
222void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
223{
224 mutex_init(&prime_fpriv->lock);
225 prime_fpriv->dmabufs = RB_ROOT;
226 prime_fpriv->handles = RB_ROOT;
227}
228
229void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
230{
231 /* by now drm_gem_release should've made sure the list is empty */
232 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
233}
234
235/**
236 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
237 * @dev: parent device for the exported dmabuf
238 * @exp_info: the export information used by dma_buf_export()
239 *
240 * This wraps dma_buf_export() for use by generic GEM drivers that are using
241 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
242 * a reference to the &drm_device and the exported &drm_gem_object (stored in
243 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
244 *
245 * Returns the new dmabuf.
246 */
247struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
248 struct dma_buf_export_info *exp_info)
249{
250 struct drm_gem_object *obj = exp_info->priv;
251 struct dma_buf *dma_buf;
252
253 dma_buf = dma_buf_export(exp_info);
254 if (IS_ERR(dma_buf))
255 return dma_buf;
256
257 drm_dev_get(dev);
258 drm_gem_object_get(obj);
259 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
260
261 return dma_buf;
262}
263EXPORT_SYMBOL(drm_gem_dmabuf_export);
264
265/**
266 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
267 * @dma_buf: buffer to be released
268 *
269 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
270 * must use this in their &dma_buf_ops structure as the release callback.
271 * drm_gem_dmabuf_release() should be used in conjunction with
272 * drm_gem_dmabuf_export().
273 */
274void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
275{
276 struct drm_gem_object *obj = dma_buf->priv;
277 struct drm_device *dev = obj->dev;
278
279 /* drop the reference on the export fd holds */
280 drm_gem_object_put(obj);
281
282 drm_dev_put(dev);
283}
284EXPORT_SYMBOL(drm_gem_dmabuf_release);
285
286/**
287 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
288 * @dev: dev to export the buffer from
289 * @file_priv: drm file-private structure
290 * @prime_fd: fd id of the dma-buf which should be imported
291 * @handle: pointer to storage for the handle of the imported buffer object
292 *
293 * This is the PRIME import function which must be used mandatorily by GEM
294 * drivers to ensure correct lifetime management of the underlying GEM object.
295 * The actual importing of GEM object from the dma-buf is done through the
296 * &drm_driver.gem_prime_import driver callback.
297 *
298 * Returns 0 on success or a negative error code on failure.
299 */
300int drm_gem_prime_fd_to_handle(struct drm_device *dev,
301 struct drm_file *file_priv, int prime_fd,
302 uint32_t *handle)
303{
304 struct dma_buf *dma_buf;
305 struct drm_gem_object *obj;
306 int ret;
307
308 dma_buf = dma_buf_get(prime_fd);
309 if (IS_ERR(dma_buf))
310 return PTR_ERR(dma_buf);
311
312 mutex_lock(&file_priv->prime.lock);
313
314 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
315 dma_buf, handle);
316 if (ret == 0)
317 goto out_put;
318
319 /* never seen this one, need to import */
320 mutex_lock(&dev->object_name_lock);
321 if (dev->driver->gem_prime_import)
322 obj = dev->driver->gem_prime_import(dev, dma_buf);
323 else
324 obj = drm_gem_prime_import(dev, dma_buf);
325 if (IS_ERR(obj)) {
326 ret = PTR_ERR(obj);
327 goto out_unlock;
328 }
329
330 if (obj->dma_buf) {
331 WARN_ON(obj->dma_buf != dma_buf);
332 } else {
333 obj->dma_buf = dma_buf;
334 get_dma_buf(dma_buf);
335 }
336
337 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
338 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
339 drm_gem_object_put(obj);
340 if (ret)
341 goto out_put;
342
343 ret = drm_prime_add_buf_handle(&file_priv->prime,
344 dma_buf, *handle);
345 mutex_unlock(&file_priv->prime.lock);
346 if (ret)
347 goto fail;
348
349 dma_buf_put(dma_buf);
350
351 return 0;
352
353fail:
354 /* hmm, if driver attached, we are relying on the free-object path
355 * to detach.. which seems ok..
356 */
357 drm_gem_handle_delete(file_priv, *handle);
358 dma_buf_put(dma_buf);
359 return ret;
360
361out_unlock:
362 mutex_unlock(&dev->object_name_lock);
363out_put:
364 mutex_unlock(&file_priv->prime.lock);
365 dma_buf_put(dma_buf);
366 return ret;
367}
368EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
369
370int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
371 struct drm_file *file_priv)
372{
373 struct drm_prime_handle *args = data;
374
375 if (!dev->driver->prime_fd_to_handle)
376 return -ENOSYS;
377
378 return dev->driver->prime_fd_to_handle(dev, file_priv,
379 args->fd, &args->handle);
380}
381
382static struct dma_buf *export_and_register_object(struct drm_device *dev,
383 struct drm_gem_object *obj,
384 uint32_t flags)
385{
386 struct dma_buf *dmabuf;
387
388 /* prevent races with concurrent gem_close. */
389 if (obj->handle_count == 0) {
390 dmabuf = ERR_PTR(-ENOENT);
391 return dmabuf;
392 }
393
394 if (obj->funcs && obj->funcs->export)
395 dmabuf = obj->funcs->export(obj, flags);
396 else
397 dmabuf = drm_gem_prime_export(obj, flags);
398 if (IS_ERR(dmabuf)) {
399 /* normally the created dma-buf takes ownership of the ref,
400 * but if that fails then drop the ref
401 */
402 return dmabuf;
403 }
404
405 /*
406 * Note that callers do not need to clean up the export cache
407 * since the check for obj->handle_count guarantees that someone
408 * will clean it up.
409 */
410 obj->dma_buf = dmabuf;
411 get_dma_buf(obj->dma_buf);
412
413 return dmabuf;
414}
415
416/**
417 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
418 * @dev: dev to export the buffer from
419 * @file_priv: drm file-private structure
420 * @handle: buffer handle to export
421 * @flags: flags like DRM_CLOEXEC
422 * @prime_fd: pointer to storage for the fd id of the create dma-buf
423 *
424 * This is the PRIME export function which must be used mandatorily by GEM
425 * drivers to ensure correct lifetime management of the underlying GEM object.
426 * The actual exporting from GEM object to a dma-buf is done through the
427 * &drm_gem_object_funcs.export callback.
428 */
429int drm_gem_prime_handle_to_fd(struct drm_device *dev,
430 struct drm_file *file_priv, uint32_t handle,
431 uint32_t flags,
432 int *prime_fd)
433{
434 struct drm_gem_object *obj;
435 int ret = 0;
436 struct dma_buf *dmabuf;
437
438 mutex_lock(&file_priv->prime.lock);
439 obj = drm_gem_object_lookup(file_priv, handle);
440 if (!obj) {
441 ret = -ENOENT;
442 goto out_unlock;
443 }
444
445 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
446 if (dmabuf) {
447 get_dma_buf(dmabuf);
448 goto out_have_handle;
449 }
450
451 mutex_lock(&dev->object_name_lock);
452 /* re-export the original imported object */
453 if (obj->import_attach) {
454 dmabuf = obj->import_attach->dmabuf;
455 get_dma_buf(dmabuf);
456 goto out_have_obj;
457 }
458
459 if (obj->dma_buf) {
460 get_dma_buf(obj->dma_buf);
461 dmabuf = obj->dma_buf;
462 goto out_have_obj;
463 }
464
465 dmabuf = export_and_register_object(dev, obj, flags);
466 if (IS_ERR(dmabuf)) {
467 /* normally the created dma-buf takes ownership of the ref,
468 * but if that fails then drop the ref
469 */
470 ret = PTR_ERR(dmabuf);
471 mutex_unlock(&dev->object_name_lock);
472 goto out;
473 }
474
475out_have_obj:
476 /*
477 * If we've exported this buffer then cheat and add it to the import list
478 * so we get the correct handle back. We must do this under the
479 * protection of dev->object_name_lock to ensure that a racing gem close
480 * ioctl doesn't miss to remove this buffer handle from the cache.
481 */
482 ret = drm_prime_add_buf_handle(&file_priv->prime,
483 dmabuf, handle);
484 mutex_unlock(&dev->object_name_lock);
485 if (ret)
486 goto fail_put_dmabuf;
487
488out_have_handle:
489 ret = dma_buf_fd(dmabuf, flags);
490 /*
491 * We must _not_ remove the buffer from the handle cache since the newly
492 * created dma buf is already linked in the global obj->dma_buf pointer,
493 * and that is invariant as long as a userspace gem handle exists.
494 * Closing the handle will clean out the cache anyway, so we don't leak.
495 */
496 if (ret < 0) {
497 goto fail_put_dmabuf;
498 } else {
499 *prime_fd = ret;
500 ret = 0;
501 }
502
503 goto out;
504
505fail_put_dmabuf:
506 dma_buf_put(dmabuf);
507out:
508 drm_gem_object_put(obj);
509out_unlock:
510 mutex_unlock(&file_priv->prime.lock);
511
512 return ret;
513}
514EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
515
516int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
517 struct drm_file *file_priv)
518{
519 struct drm_prime_handle *args = data;
520
521 if (!dev->driver->prime_handle_to_fd)
522 return -ENOSYS;
523
524 /* check flags are valid */
525 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
526 return -EINVAL;
527
528 return dev->driver->prime_handle_to_fd(dev, file_priv,
529 args->handle, args->flags, &args->fd);
530}
531
532/**
533 * DOC: PRIME Helpers
534 *
535 * Drivers can implement &drm_gem_object_funcs.export and
536 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
537 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
538 * implement dma-buf support in terms of some lower-level helpers, which are
539 * again exported for drivers to use individually:
540 *
541 * Exporting buffers
542 * ~~~~~~~~~~~~~~~~~
543 *
544 * Optional pinning of buffers is handled at dma-buf attach and detach time in
545 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
546 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
547 * &drm_gem_object_funcs.get_sg_table.
548 *
549 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
550 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
551 * drm_gem_dmabuf_mmap().
552 *
553 * Note that these export helpers can only be used if the underlying backing
554 * storage is fully coherent and either permanently pinned, or it is safe to pin
555 * it indefinitely.
556 *
557 * FIXME: The underlying helper functions are named rather inconsistently.
558 *
559 * Importing buffers
560 * ~~~~~~~~~~~~~~~~~
561 *
562 * Importing dma-bufs using drm_gem_prime_import() relies on
563 * &drm_driver.gem_prime_import_sg_table.
564 *
565 * Note that similarly to the export helpers this permanently pins the
566 * underlying backing storage. Which is ok for scanout, but is not the best
567 * option for sharing lots of buffers for rendering.
568 */
569
570/**
571 * drm_gem_map_attach - dma_buf attach implementation for GEM
572 * @dma_buf: buffer to attach device to
573 * @attach: buffer attachment data
574 *
575 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
576 * used as the &dma_buf_ops.attach callback. Must be used together with
577 * drm_gem_map_detach().
578 *
579 * Returns 0 on success, negative error code on failure.
580 */
581int drm_gem_map_attach(struct dma_buf *dma_buf,
582 struct dma_buf_attachment *attach)
583{
584 struct drm_gem_object *obj = dma_buf->priv;
585
586 return drm_gem_pin(obj);
587}
588EXPORT_SYMBOL(drm_gem_map_attach);
589
590/**
591 * drm_gem_map_detach - dma_buf detach implementation for GEM
592 * @dma_buf: buffer to detach from
593 * @attach: attachment to be detached
594 *
595 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
596 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
597 * &dma_buf_ops.detach callback.
598 */
599void drm_gem_map_detach(struct dma_buf *dma_buf,
600 struct dma_buf_attachment *attach)
601{
602 struct drm_gem_object *obj = dma_buf->priv;
603
604 drm_gem_unpin(obj);
605}
606EXPORT_SYMBOL(drm_gem_map_detach);
607
608/**
609 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
610 * @attach: attachment whose scatterlist is to be returned
611 * @dir: direction of DMA transfer
612 *
613 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
614 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
615 * with drm_gem_unmap_dma_buf().
616 *
617 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
618 * on error. May return -EINTR if it is interrupted by a signal.
619 */
620struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
621 enum dma_data_direction dir)
622{
623 struct drm_gem_object *obj = attach->dmabuf->priv;
624 struct sg_table *sgt;
625 int ret;
626
627 if (WARN_ON(dir == DMA_NONE))
628 return ERR_PTR(-EINVAL);
629
630 if (WARN_ON(!obj->funcs->get_sg_table))
631 return ERR_PTR(-ENOSYS);
632
633 sgt = obj->funcs->get_sg_table(obj);
634 if (IS_ERR(sgt))
635 return sgt;
636
637 ret = dma_map_sgtable(attach->dev, sgt, dir,
638 DMA_ATTR_SKIP_CPU_SYNC);
639 if (ret) {
640 sg_free_table(sgt);
641 kfree(sgt);
642 sgt = ERR_PTR(ret);
643 }
644
645 return sgt;
646}
647EXPORT_SYMBOL(drm_gem_map_dma_buf);
648
649/**
650 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
651 * @attach: attachment to unmap buffer from
652 * @sgt: scatterlist info of the buffer to unmap
653 * @dir: direction of DMA transfer
654 *
655 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
656 */
657void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
658 struct sg_table *sgt,
659 enum dma_data_direction dir)
660{
661 if (!sgt)
662 return;
663
664 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
665 sg_free_table(sgt);
666 kfree(sgt);
667}
668EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
669
670/**
671 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
672 * @dma_buf: buffer to be mapped
673 * @map: the virtual address of the buffer
674 *
675 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
676 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
677 * The kernel virtual address is returned in map.
678 *
679 * Returns 0 on success or a negative errno code otherwise.
680 */
681int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
682{
683 struct drm_gem_object *obj = dma_buf->priv;
684
685 return drm_gem_vmap(obj, map);
686}
687EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
688
689/**
690 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
691 * @dma_buf: buffer to be unmapped
692 * @map: the virtual address of the buffer
693 *
694 * Releases a kernel virtual mapping. This can be used as the
695 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
696 */
697void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
698{
699 struct drm_gem_object *obj = dma_buf->priv;
700
701 drm_gem_vunmap(obj, map);
702}
703EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
704
705/**
706 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
707 * @obj: GEM object
708 * @vma: Virtual address range
709 *
710 * This function sets up a userspace mapping for PRIME exported buffers using
711 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
712 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
713 * called to set up the mapping.
714 *
715 * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
716 */
717int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
718{
719 struct drm_file *priv;
720 struct file *fil;
721 int ret;
722
723 /* Add the fake offset */
724 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
725
726 if (obj->funcs && obj->funcs->mmap) {
727 vma->vm_ops = obj->funcs->vm_ops;
728
729 drm_gem_object_get(obj);
730 ret = obj->funcs->mmap(obj, vma);
731 if (ret) {
732 drm_gem_object_put(obj);
733 return ret;
734 }
735 vma->vm_private_data = obj;
736 return 0;
737 }
738
739 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
740 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
741 if (!priv || !fil) {
742 ret = -ENOMEM;
743 goto out;
744 }
745
746 /* Used by drm_gem_mmap() to lookup the GEM object */
747 priv->minor = obj->dev->primary;
748 fil->private_data = priv;
749
750 ret = drm_vma_node_allow(&obj->vma_node, priv);
751 if (ret)
752 goto out;
753
754 ret = obj->dev->driver->fops->mmap(fil, vma);
755
756 drm_vma_node_revoke(&obj->vma_node, priv);
757out:
758 kfree(priv);
759 kfree(fil);
760
761 return ret;
762}
763EXPORT_SYMBOL(drm_gem_prime_mmap);
764
765/**
766 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
767 * @dma_buf: buffer to be mapped
768 * @vma: virtual address range
769 *
770 * Provides memory mapping for the buffer. This can be used as the
771 * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
772 * which should be set to drm_gem_prime_mmap().
773 *
774 * FIXME: There's really no point to this wrapper, drivers which need anything
775 * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
776 *
777 * Returns 0 on success or a negative error code on failure.
778 */
779int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
780{
781 struct drm_gem_object *obj = dma_buf->priv;
782 struct drm_device *dev = obj->dev;
783
784 dma_resv_assert_held(dma_buf->resv);
785
786 if (!dev->driver->gem_prime_mmap)
787 return -ENOSYS;
788
789 return dev->driver->gem_prime_mmap(obj, vma);
790}
791EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
792
793static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
794 .cache_sgt_mapping = true,
795 .attach = drm_gem_map_attach,
796 .detach = drm_gem_map_detach,
797 .map_dma_buf = drm_gem_map_dma_buf,
798 .unmap_dma_buf = drm_gem_unmap_dma_buf,
799 .release = drm_gem_dmabuf_release,
800 .mmap = drm_gem_dmabuf_mmap,
801 .vmap = drm_gem_dmabuf_vmap,
802 .vunmap = drm_gem_dmabuf_vunmap,
803};
804
805/**
806 * drm_prime_pages_to_sg - converts a page array into an sg list
807 * @dev: DRM device
808 * @pages: pointer to the array of page pointers to convert
809 * @nr_pages: length of the page vector
810 *
811 * This helper creates an sg table object from a set of pages
812 * the driver is responsible for mapping the pages into the
813 * importers address space for use with dma_buf itself.
814 *
815 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
816 */
817struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
818 struct page **pages, unsigned int nr_pages)
819{
820 struct sg_table *sg;
821 size_t max_segment = 0;
822 int err;
823
824 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
825 if (!sg)
826 return ERR_PTR(-ENOMEM);
827
828 if (dev)
829 max_segment = dma_max_mapping_size(dev->dev);
830 if (max_segment == 0)
831 max_segment = UINT_MAX;
832 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
833 nr_pages << PAGE_SHIFT,
834 max_segment, GFP_KERNEL);
835 if (err) {
836 kfree(sg);
837 sg = ERR_PTR(err);
838 }
839 return sg;
840}
841EXPORT_SYMBOL(drm_prime_pages_to_sg);
842
843/**
844 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
845 * @sgt: sg_table describing the buffer to check
846 *
847 * This helper calculates the contiguous size in the DMA address space
848 * of the buffer described by the provided sg_table.
849 *
850 * This is useful for implementing
851 * &drm_gem_object_funcs.gem_prime_import_sg_table.
852 */
853unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
854{
855 dma_addr_t expected = sg_dma_address(sgt->sgl);
856 struct scatterlist *sg;
857 unsigned long size = 0;
858 int i;
859
860 for_each_sgtable_dma_sg(sgt, sg, i) {
861 unsigned int len = sg_dma_len(sg);
862
863 if (!len)
864 break;
865 if (sg_dma_address(sg) != expected)
866 break;
867 expected += len;
868 size += len;
869 }
870 return size;
871}
872EXPORT_SYMBOL(drm_prime_get_contiguous_size);
873
874/**
875 * drm_gem_prime_export - helper library implementation of the export callback
876 * @obj: GEM object to export
877 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
878 *
879 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
880 * using the PRIME helpers. It is used as the default in
881 * drm_gem_prime_handle_to_fd().
882 */
883struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
884 int flags)
885{
886 struct drm_device *dev = obj->dev;
887 struct dma_buf_export_info exp_info = {
888 .exp_name = KBUILD_MODNAME, /* white lie for debug */
889 .owner = dev->driver->fops->owner,
890 .ops = &drm_gem_prime_dmabuf_ops,
891 .size = obj->size,
892 .flags = flags,
893 .priv = obj,
894 .resv = obj->resv,
895 };
896
897 return drm_gem_dmabuf_export(dev, &exp_info);
898}
899EXPORT_SYMBOL(drm_gem_prime_export);
900
901/**
902 * drm_gem_prime_import_dev - core implementation of the import callback
903 * @dev: drm_device to import into
904 * @dma_buf: dma-buf object to import
905 * @attach_dev: struct device to dma_buf attach
906 *
907 * This is the core of drm_gem_prime_import(). It's designed to be called by
908 * drivers who want to use a different device structure than &drm_device.dev for
909 * attaching via dma_buf. This function calls
910 * &drm_driver.gem_prime_import_sg_table internally.
911 *
912 * Drivers must arrange to call drm_prime_gem_destroy() from their
913 * &drm_gem_object_funcs.free hook when using this function.
914 */
915struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
916 struct dma_buf *dma_buf,
917 struct device *attach_dev)
918{
919 struct dma_buf_attachment *attach;
920 struct sg_table *sgt;
921 struct drm_gem_object *obj;
922 int ret;
923
924 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
925 obj = dma_buf->priv;
926 if (obj->dev == dev) {
927 /*
928 * Importing dmabuf exported from out own gem increases
929 * refcount on gem itself instead of f_count of dmabuf.
930 */
931 drm_gem_object_get(obj);
932 return obj;
933 }
934 }
935
936 if (!dev->driver->gem_prime_import_sg_table)
937 return ERR_PTR(-EINVAL);
938
939 attach = dma_buf_attach(dma_buf, attach_dev);
940 if (IS_ERR(attach))
941 return ERR_CAST(attach);
942
943 get_dma_buf(dma_buf);
944
945 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
946 if (IS_ERR(sgt)) {
947 ret = PTR_ERR(sgt);
948 goto fail_detach;
949 }
950
951 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
952 if (IS_ERR(obj)) {
953 ret = PTR_ERR(obj);
954 goto fail_unmap;
955 }
956
957 obj->import_attach = attach;
958 obj->resv = dma_buf->resv;
959
960 return obj;
961
962fail_unmap:
963 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
964fail_detach:
965 dma_buf_detach(dma_buf, attach);
966 dma_buf_put(dma_buf);
967
968 return ERR_PTR(ret);
969}
970EXPORT_SYMBOL(drm_gem_prime_import_dev);
971
972/**
973 * drm_gem_prime_import - helper library implementation of the import callback
974 * @dev: drm_device to import into
975 * @dma_buf: dma-buf object to import
976 *
977 * This is the implementation of the gem_prime_import functions for GEM drivers
978 * using the PRIME helpers. Drivers can use this as their
979 * &drm_driver.gem_prime_import implementation. It is used as the default
980 * implementation in drm_gem_prime_fd_to_handle().
981 *
982 * Drivers must arrange to call drm_prime_gem_destroy() from their
983 * &drm_gem_object_funcs.free hook when using this function.
984 */
985struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
986 struct dma_buf *dma_buf)
987{
988 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
989}
990EXPORT_SYMBOL(drm_gem_prime_import);
991
992/**
993 * drm_prime_sg_to_page_array - convert an sg table into a page array
994 * @sgt: scatter-gather table to convert
995 * @pages: array of page pointers to store the pages in
996 * @max_entries: size of the passed-in array
997 *
998 * Exports an sg table into an array of pages.
999 *
1000 * This function is deprecated and strongly discouraged to be used.
1001 * The page array is only useful for page faults and those can corrupt fields
1002 * in the struct page if they are not handled by the exporting driver.
1003 */
1004int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
1005 struct page **pages,
1006 int max_entries)
1007{
1008 struct sg_page_iter page_iter;
1009 struct page **p = pages;
1010
1011 for_each_sgtable_page(sgt, &page_iter, 0) {
1012 if (WARN_ON(p - pages >= max_entries))
1013 return -1;
1014 *p++ = sg_page_iter_page(&page_iter);
1015 }
1016 return 0;
1017}
1018EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1019
1020/**
1021 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1022 * @sgt: scatter-gather table to convert
1023 * @addrs: array to store the dma bus address of each page
1024 * @max_entries: size of both the passed-in arrays
1025 *
1026 * Exports an sg table into an array of addresses.
1027 *
1028 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1029 * implementation.
1030 */
1031int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1032 int max_entries)
1033{
1034 struct sg_dma_page_iter dma_iter;
1035 dma_addr_t *a = addrs;
1036
1037 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1038 if (WARN_ON(a - addrs >= max_entries))
1039 return -1;
1040 *a++ = sg_page_iter_dma_address(&dma_iter);
1041 }
1042 return 0;
1043}
1044EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1045
1046/**
1047 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1048 * @obj: GEM object which was created from a dma-buf
1049 * @sg: the sg-table which was pinned at import time
1050 *
1051 * This is the cleanup functions which GEM drivers need to call when they use
1052 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1053 */
1054void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1055{
1056 struct dma_buf_attachment *attach;
1057 struct dma_buf *dma_buf;
1058
1059 attach = obj->import_attach;
1060 if (sg)
1061 dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
1062 dma_buf = attach->dmabuf;
1063 dma_buf_detach(attach->dmabuf, attach);
1064 /* remove the reference */
1065 dma_buf_put(dma_buf);
1066}
1067EXPORT_SYMBOL(drm_prime_gem_destroy);