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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 <drm/drm_prime.h>
33#include <drm/drm_gem.h>
34#include <drm/drmP.h>
35
36#include "drm_internal.h"
37
38/*
39 * DMA-BUF/GEM Object references and lifetime overview:
40 *
41 * On the export the dma_buf holds a reference to the exporting GEM
42 * object. It takes this reference in handle_to_fd_ioctl, when it
43 * first calls .prime_export and stores the exporting GEM object in
44 * the dma_buf priv. This reference needs to be released when the
45 * final reference to the &dma_buf itself is dropped and its
46 * &dma_buf_ops.release function is called. For GEM-based drivers,
47 * the dma_buf should be exported using drm_gem_dmabuf_export() and
48 * then released by drm_gem_dmabuf_release().
49 *
50 * On the import the importing GEM object holds a reference to the
51 * dma_buf (which in turn holds a ref to the exporting GEM object).
52 * It takes that reference in the fd_to_handle ioctl.
53 * It calls dma_buf_get, creates an attachment to it and stores the
54 * attachment in the GEM object. When this attachment is destroyed
55 * when the imported object is destroyed, we remove the attachment
56 * and drop the reference to the dma_buf.
57 *
58 * When all the references to the &dma_buf are dropped, i.e. when
59 * userspace has closed both handles to the imported GEM object (through the
60 * FD_TO_HANDLE IOCTL) and closed the file descriptor of the exported
61 * (through the HANDLE_TO_FD IOCTL) dma_buf, and all kernel-internal references
62 * are also gone, then the dma_buf gets destroyed. This can also happen as a
63 * part of the clean up procedure in the drm_release() function if userspace
64 * fails to properly clean up. Note that both the kernel and userspace (by
65 * keeeping the PRIME file descriptors open) can hold references onto a
66 * &dma_buf.
67 *
68 * Thus the chain of references always flows in one direction
69 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
70 *
71 * Self-importing: if userspace is using PRIME as a replacement for flink
72 * then it will get a fd->handle request for a GEM object that it created.
73 * Drivers should detect this situation and return back the gem object
74 * from the dma-buf private. Prime will do this automatically for drivers that
75 * use the drm_gem_prime_{import,export} helpers.
76 *
77 * GEM struct &dma_buf_ops symbols are now exported. They can be resued by
78 * drivers which implement GEM interface.
79 */
80
81struct drm_prime_member {
82 struct dma_buf *dma_buf;
83 uint32_t handle;
84
85 struct rb_node dmabuf_rb;
86 struct rb_node handle_rb;
87};
88
89struct drm_prime_attachment {
90 struct sg_table *sgt;
91 enum dma_data_direction dir;
92};
93
94static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
95 struct dma_buf *dma_buf, uint32_t handle)
96{
97 struct drm_prime_member *member;
98 struct rb_node **p, *rb;
99
100 member = kmalloc(sizeof(*member), GFP_KERNEL);
101 if (!member)
102 return -ENOMEM;
103
104 get_dma_buf(dma_buf);
105 member->dma_buf = dma_buf;
106 member->handle = handle;
107
108 rb = NULL;
109 p = &prime_fpriv->dmabufs.rb_node;
110 while (*p) {
111 struct drm_prime_member *pos;
112
113 rb = *p;
114 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
115 if (dma_buf > pos->dma_buf)
116 p = &rb->rb_right;
117 else
118 p = &rb->rb_left;
119 }
120 rb_link_node(&member->dmabuf_rb, rb, p);
121 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
122
123 rb = NULL;
124 p = &prime_fpriv->handles.rb_node;
125 while (*p) {
126 struct drm_prime_member *pos;
127
128 rb = *p;
129 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
130 if (handle > pos->handle)
131 p = &rb->rb_right;
132 else
133 p = &rb->rb_left;
134 }
135 rb_link_node(&member->handle_rb, rb, p);
136 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
137
138 return 0;
139}
140
141static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
142 uint32_t handle)
143{
144 struct rb_node *rb;
145
146 rb = prime_fpriv->handles.rb_node;
147 while (rb) {
148 struct drm_prime_member *member;
149
150 member = rb_entry(rb, struct drm_prime_member, handle_rb);
151 if (member->handle == handle)
152 return member->dma_buf;
153 else if (member->handle < handle)
154 rb = rb->rb_right;
155 else
156 rb = rb->rb_left;
157 }
158
159 return NULL;
160}
161
162static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
163 struct dma_buf *dma_buf,
164 uint32_t *handle)
165{
166 struct rb_node *rb;
167
168 rb = prime_fpriv->dmabufs.rb_node;
169 while (rb) {
170 struct drm_prime_member *member;
171
172 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
173 if (member->dma_buf == dma_buf) {
174 *handle = member->handle;
175 return 0;
176 } else if (member->dma_buf < dma_buf) {
177 rb = rb->rb_right;
178 } else {
179 rb = rb->rb_left;
180 }
181 }
182
183 return -ENOENT;
184}
185
186/**
187 * drm_gem_map_attach - dma_buf attach implementation for GEM
188 * @dma_buf: buffer to attach device to
189 * @target_dev: not used
190 * @attach: buffer attachment data
191 *
192 * Allocates &drm_prime_attachment and calls &drm_driver.gem_prime_pin for
193 * device specific attachment. This can be used as the &dma_buf_ops.attach
194 * callback.
195 *
196 * Returns 0 on success, negative error code on failure.
197 */
198int drm_gem_map_attach(struct dma_buf *dma_buf, struct device *target_dev,
199 struct dma_buf_attachment *attach)
200{
201 struct drm_prime_attachment *prime_attach;
202 struct drm_gem_object *obj = dma_buf->priv;
203 struct drm_device *dev = obj->dev;
204
205 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
206 if (!prime_attach)
207 return -ENOMEM;
208
209 prime_attach->dir = DMA_NONE;
210 attach->priv = prime_attach;
211
212 if (!dev->driver->gem_prime_pin)
213 return 0;
214
215 return dev->driver->gem_prime_pin(obj);
216}
217EXPORT_SYMBOL(drm_gem_map_attach);
218
219/**
220 * drm_gem_map_detach - dma_buf detach implementation for GEM
221 * @dma_buf: buffer to detach from
222 * @attach: attachment to be detached
223 *
224 * Cleans up &dma_buf_attachment. This can be used as the &dma_buf_ops.detach
225 * callback.
226 */
227void drm_gem_map_detach(struct dma_buf *dma_buf,
228 struct dma_buf_attachment *attach)
229{
230 struct drm_prime_attachment *prime_attach = attach->priv;
231 struct drm_gem_object *obj = dma_buf->priv;
232 struct drm_device *dev = obj->dev;
233
234 if (prime_attach) {
235 struct sg_table *sgt = prime_attach->sgt;
236
237 if (sgt) {
238 if (prime_attach->dir != DMA_NONE)
239 dma_unmap_sg_attrs(attach->dev, sgt->sgl,
240 sgt->nents,
241 prime_attach->dir,
242 DMA_ATTR_SKIP_CPU_SYNC);
243 sg_free_table(sgt);
244 }
245
246 kfree(sgt);
247 kfree(prime_attach);
248 attach->priv = NULL;
249 }
250
251 if (dev->driver->gem_prime_unpin)
252 dev->driver->gem_prime_unpin(obj);
253}
254EXPORT_SYMBOL(drm_gem_map_detach);
255
256void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
257 struct dma_buf *dma_buf)
258{
259 struct rb_node *rb;
260
261 rb = prime_fpriv->dmabufs.rb_node;
262 while (rb) {
263 struct drm_prime_member *member;
264
265 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
266 if (member->dma_buf == dma_buf) {
267 rb_erase(&member->handle_rb, &prime_fpriv->handles);
268 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
269
270 dma_buf_put(dma_buf);
271 kfree(member);
272 return;
273 } else if (member->dma_buf < dma_buf) {
274 rb = rb->rb_right;
275 } else {
276 rb = rb->rb_left;
277 }
278 }
279}
280
281/**
282 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
283 * @attach: attachment whose scatterlist is to be returned
284 * @dir: direction of DMA transfer
285 *
286 * Calls &drm_driver.gem_prime_get_sg_table and then maps the scatterlist. This
287 * can be used as the &dma_buf_ops.map_dma_buf callback.
288 *
289 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
290 * on error. May return -EINTR if it is interrupted by a signal.
291 */
292
293struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
294 enum dma_data_direction dir)
295{
296 struct drm_prime_attachment *prime_attach = attach->priv;
297 struct drm_gem_object *obj = attach->dmabuf->priv;
298 struct sg_table *sgt;
299
300 if (WARN_ON(dir == DMA_NONE || !prime_attach))
301 return ERR_PTR(-EINVAL);
302
303 /* return the cached mapping when possible */
304 if (prime_attach->dir == dir)
305 return prime_attach->sgt;
306
307 /*
308 * two mappings with different directions for the same attachment are
309 * not allowed
310 */
311 if (WARN_ON(prime_attach->dir != DMA_NONE))
312 return ERR_PTR(-EBUSY);
313
314 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
315
316 if (!IS_ERR(sgt)) {
317 if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
318 DMA_ATTR_SKIP_CPU_SYNC)) {
319 sg_free_table(sgt);
320 kfree(sgt);
321 sgt = ERR_PTR(-ENOMEM);
322 } else {
323 prime_attach->sgt = sgt;
324 prime_attach->dir = dir;
325 }
326 }
327
328 return sgt;
329}
330EXPORT_SYMBOL(drm_gem_map_dma_buf);
331
332/**
333 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
334 *
335 * Not implemented. The unmap is done at drm_gem_map_detach(). This can be
336 * used as the &dma_buf_ops.unmap_dma_buf callback.
337 */
338void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
339 struct sg_table *sgt,
340 enum dma_data_direction dir)
341{
342 /* nothing to be done here */
343}
344EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
345
346/**
347 * drm_gem_dmabuf_export - dma_buf export implementation for GEM
348 * @dev: parent device for the exported dmabuf
349 * @exp_info: the export information used by dma_buf_export()
350 *
351 * This wraps dma_buf_export() for use by generic GEM drivers that are using
352 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
353 * a reference to the &drm_device and the exported &drm_gem_object (stored in
354 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
355 *
356 * Returns the new dmabuf.
357 */
358struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
359 struct dma_buf_export_info *exp_info)
360{
361 struct dma_buf *dma_buf;
362
363 dma_buf = dma_buf_export(exp_info);
364 if (IS_ERR(dma_buf))
365 return dma_buf;
366
367 drm_dev_get(dev);
368 drm_gem_object_get(exp_info->priv);
369
370 return dma_buf;
371}
372EXPORT_SYMBOL(drm_gem_dmabuf_export);
373
374/**
375 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
376 * @dma_buf: buffer to be released
377 *
378 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
379 * must use this in their dma_buf ops structure as the release callback.
380 * drm_gem_dmabuf_release() should be used in conjunction with
381 * drm_gem_dmabuf_export().
382 */
383void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
384{
385 struct drm_gem_object *obj = dma_buf->priv;
386 struct drm_device *dev = obj->dev;
387
388 /* drop the reference on the export fd holds */
389 drm_gem_object_put_unlocked(obj);
390
391 drm_dev_put(dev);
392}
393EXPORT_SYMBOL(drm_gem_dmabuf_release);
394
395/**
396 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
397 * @dma_buf: buffer to be mapped
398 *
399 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
400 * callback.
401 *
402 * Returns the kernel virtual address.
403 */
404void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
405{
406 struct drm_gem_object *obj = dma_buf->priv;
407 struct drm_device *dev = obj->dev;
408
409 return dev->driver->gem_prime_vmap(obj);
410}
411EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
412
413/**
414 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
415 * @dma_buf: buffer to be unmapped
416 * @vaddr: the virtual address of the buffer
417 *
418 * Releases a kernel virtual mapping. This can be used as the
419 * &dma_buf_ops.vunmap callback.
420 */
421void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
422{
423 struct drm_gem_object *obj = dma_buf->priv;
424 struct drm_device *dev = obj->dev;
425
426 dev->driver->gem_prime_vunmap(obj, vaddr);
427}
428EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
429
430/**
431 * drm_gem_dmabuf_kmap_atomic - map_atomic implementation for GEM
432 *
433 * Not implemented. This can be used as the &dma_buf_ops.map_atomic callback.
434 */
435void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
436 unsigned long page_num)
437{
438 return NULL;
439}
440EXPORT_SYMBOL(drm_gem_dmabuf_kmap_atomic);
441
442/**
443 * drm_gem_dmabuf_kunmap_atomic - unmap_atomic implementation for GEM
444 *
445 * Not implemented. This can be used as the &dma_buf_ops.unmap_atomic callback.
446 */
447void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
448 unsigned long page_num, void *addr)
449{
450
451}
452EXPORT_SYMBOL(drm_gem_dmabuf_kunmap_atomic);
453
454/**
455 * drm_gem_dmabuf_kmap - map implementation for GEM
456 *
457 * Not implemented. This can be used as the &dma_buf_ops.map callback.
458 */
459void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
460{
461 return NULL;
462}
463EXPORT_SYMBOL(drm_gem_dmabuf_kmap);
464
465/**
466 * drm_gem_dmabuf_kunmap - unmap implementation for GEM
467 *
468 * Not implemented. This can be used as the &dma_buf_ops.unmap callback.
469 */
470void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num,
471 void *addr)
472{
473
474}
475EXPORT_SYMBOL(drm_gem_dmabuf_kunmap);
476
477/**
478 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
479 * @dma_buf: buffer to be mapped
480 * @vma: virtual address range
481 *
482 * Provides memory mapping for the buffer. This can be used as the
483 * &dma_buf_ops.mmap callback.
484 *
485 * Returns 0 on success or a negative error code on failure.
486 */
487int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
488{
489 struct drm_gem_object *obj = dma_buf->priv;
490 struct drm_device *dev = obj->dev;
491
492 if (!dev->driver->gem_prime_mmap)
493 return -ENOSYS;
494
495 return dev->driver->gem_prime_mmap(obj, vma);
496}
497EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
498
499static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
500 .attach = drm_gem_map_attach,
501 .detach = drm_gem_map_detach,
502 .map_dma_buf = drm_gem_map_dma_buf,
503 .unmap_dma_buf = drm_gem_unmap_dma_buf,
504 .release = drm_gem_dmabuf_release,
505 .map = drm_gem_dmabuf_kmap,
506 .map_atomic = drm_gem_dmabuf_kmap_atomic,
507 .unmap = drm_gem_dmabuf_kunmap,
508 .unmap_atomic = drm_gem_dmabuf_kunmap_atomic,
509 .mmap = drm_gem_dmabuf_mmap,
510 .vmap = drm_gem_dmabuf_vmap,
511 .vunmap = drm_gem_dmabuf_vunmap,
512};
513
514/**
515 * DOC: PRIME Helpers
516 *
517 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
518 * simpler APIs by using the helper functions @drm_gem_prime_export and
519 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
520 * six lower-level driver callbacks:
521 *
522 * Export callbacks:
523 *
524 * * @gem_prime_pin (optional): prepare a GEM object for exporting
525 * * @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
526 * * @gem_prime_vmap: vmap a buffer exported by your driver
527 * * @gem_prime_vunmap: vunmap a buffer exported by your driver
528 * * @gem_prime_mmap (optional): mmap a buffer exported by your driver
529 *
530 * Import callback:
531 *
532 * * @gem_prime_import_sg_table (import): produce a GEM object from another
533 * driver's scatter/gather table
534 */
535
536/**
537 * drm_gem_prime_export - helper library implementation of the export callback
538 * @dev: drm_device to export from
539 * @obj: GEM object to export
540 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
541 *
542 * This is the implementation of the gem_prime_export functions for GEM drivers
543 * using the PRIME helpers.
544 */
545struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
546 struct drm_gem_object *obj,
547 int flags)
548{
549 struct dma_buf_export_info exp_info = {
550 .exp_name = KBUILD_MODNAME, /* white lie for debug */
551 .owner = dev->driver->fops->owner,
552 .ops = &drm_gem_prime_dmabuf_ops,
553 .size = obj->size,
554 .flags = flags,
555 .priv = obj,
556 };
557
558 if (dev->driver->gem_prime_res_obj)
559 exp_info.resv = dev->driver->gem_prime_res_obj(obj);
560
561 return drm_gem_dmabuf_export(dev, &exp_info);
562}
563EXPORT_SYMBOL(drm_gem_prime_export);
564
565static struct dma_buf *export_and_register_object(struct drm_device *dev,
566 struct drm_gem_object *obj,
567 uint32_t flags)
568{
569 struct dma_buf *dmabuf;
570
571 /* prevent races with concurrent gem_close. */
572 if (obj->handle_count == 0) {
573 dmabuf = ERR_PTR(-ENOENT);
574 return dmabuf;
575 }
576
577 dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
578 if (IS_ERR(dmabuf)) {
579 /* normally the created dma-buf takes ownership of the ref,
580 * but if that fails then drop the ref
581 */
582 return dmabuf;
583 }
584
585 /*
586 * Note that callers do not need to clean up the export cache
587 * since the check for obj->handle_count guarantees that someone
588 * will clean it up.
589 */
590 obj->dma_buf = dmabuf;
591 get_dma_buf(obj->dma_buf);
592
593 return dmabuf;
594}
595
596/**
597 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
598 * @dev: dev to export the buffer from
599 * @file_priv: drm file-private structure
600 * @handle: buffer handle to export
601 * @flags: flags like DRM_CLOEXEC
602 * @prime_fd: pointer to storage for the fd id of the create dma-buf
603 *
604 * This is the PRIME export function which must be used mandatorily by GEM
605 * drivers to ensure correct lifetime management of the underlying GEM object.
606 * The actual exporting from GEM object to a dma-buf is done through the
607 * gem_prime_export driver callback.
608 */
609int drm_gem_prime_handle_to_fd(struct drm_device *dev,
610 struct drm_file *file_priv, uint32_t handle,
611 uint32_t flags,
612 int *prime_fd)
613{
614 struct drm_gem_object *obj;
615 int ret = 0;
616 struct dma_buf *dmabuf;
617
618 mutex_lock(&file_priv->prime.lock);
619 obj = drm_gem_object_lookup(file_priv, handle);
620 if (!obj) {
621 ret = -ENOENT;
622 goto out_unlock;
623 }
624
625 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
626 if (dmabuf) {
627 get_dma_buf(dmabuf);
628 goto out_have_handle;
629 }
630
631 mutex_lock(&dev->object_name_lock);
632 /* re-export the original imported object */
633 if (obj->import_attach) {
634 dmabuf = obj->import_attach->dmabuf;
635 get_dma_buf(dmabuf);
636 goto out_have_obj;
637 }
638
639 if (obj->dma_buf) {
640 get_dma_buf(obj->dma_buf);
641 dmabuf = obj->dma_buf;
642 goto out_have_obj;
643 }
644
645 dmabuf = export_and_register_object(dev, obj, flags);
646 if (IS_ERR(dmabuf)) {
647 /* normally the created dma-buf takes ownership of the ref,
648 * but if that fails then drop the ref
649 */
650 ret = PTR_ERR(dmabuf);
651 mutex_unlock(&dev->object_name_lock);
652 goto out;
653 }
654
655out_have_obj:
656 /*
657 * If we've exported this buffer then cheat and add it to the import list
658 * so we get the correct handle back. We must do this under the
659 * protection of dev->object_name_lock to ensure that a racing gem close
660 * ioctl doesn't miss to remove this buffer handle from the cache.
661 */
662 ret = drm_prime_add_buf_handle(&file_priv->prime,
663 dmabuf, handle);
664 mutex_unlock(&dev->object_name_lock);
665 if (ret)
666 goto fail_put_dmabuf;
667
668out_have_handle:
669 ret = dma_buf_fd(dmabuf, flags);
670 /*
671 * We must _not_ remove the buffer from the handle cache since the newly
672 * created dma buf is already linked in the global obj->dma_buf pointer,
673 * and that is invariant as long as a userspace gem handle exists.
674 * Closing the handle will clean out the cache anyway, so we don't leak.
675 */
676 if (ret < 0) {
677 goto fail_put_dmabuf;
678 } else {
679 *prime_fd = ret;
680 ret = 0;
681 }
682
683 goto out;
684
685fail_put_dmabuf:
686 dma_buf_put(dmabuf);
687out:
688 drm_gem_object_put_unlocked(obj);
689out_unlock:
690 mutex_unlock(&file_priv->prime.lock);
691
692 return ret;
693}
694EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
695
696/**
697 * drm_gem_prime_import_dev - core implementation of the import callback
698 * @dev: drm_device to import into
699 * @dma_buf: dma-buf object to import
700 * @attach_dev: struct device to dma_buf attach
701 *
702 * This is the core of drm_gem_prime_import. It's designed to be called by
703 * drivers who want to use a different device structure than dev->dev for
704 * attaching via dma_buf.
705 */
706struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
707 struct dma_buf *dma_buf,
708 struct device *attach_dev)
709{
710 struct dma_buf_attachment *attach;
711 struct sg_table *sgt;
712 struct drm_gem_object *obj;
713 int ret;
714
715 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
716 obj = dma_buf->priv;
717 if (obj->dev == dev) {
718 /*
719 * Importing dmabuf exported from out own gem increases
720 * refcount on gem itself instead of f_count of dmabuf.
721 */
722 drm_gem_object_get(obj);
723 return obj;
724 }
725 }
726
727 if (!dev->driver->gem_prime_import_sg_table)
728 return ERR_PTR(-EINVAL);
729
730 attach = dma_buf_attach(dma_buf, attach_dev);
731 if (IS_ERR(attach))
732 return ERR_CAST(attach);
733
734 get_dma_buf(dma_buf);
735
736 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
737 if (IS_ERR(sgt)) {
738 ret = PTR_ERR(sgt);
739 goto fail_detach;
740 }
741
742 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
743 if (IS_ERR(obj)) {
744 ret = PTR_ERR(obj);
745 goto fail_unmap;
746 }
747
748 obj->import_attach = attach;
749
750 return obj;
751
752fail_unmap:
753 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
754fail_detach:
755 dma_buf_detach(dma_buf, attach);
756 dma_buf_put(dma_buf);
757
758 return ERR_PTR(ret);
759}
760EXPORT_SYMBOL(drm_gem_prime_import_dev);
761
762/**
763 * drm_gem_prime_import - helper library implementation of the import callback
764 * @dev: drm_device to import into
765 * @dma_buf: dma-buf object to import
766 *
767 * This is the implementation of the gem_prime_import functions for GEM drivers
768 * using the PRIME helpers.
769 */
770struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
771 struct dma_buf *dma_buf)
772{
773 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
774}
775EXPORT_SYMBOL(drm_gem_prime_import);
776
777/**
778 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
779 * @dev: dev to export the buffer from
780 * @file_priv: drm file-private structure
781 * @prime_fd: fd id of the dma-buf which should be imported
782 * @handle: pointer to storage for the handle of the imported buffer object
783 *
784 * This is the PRIME import function which must be used mandatorily by GEM
785 * drivers to ensure correct lifetime management of the underlying GEM object.
786 * The actual importing of GEM object from the dma-buf is done through the
787 * gem_import_export driver callback.
788 */
789int drm_gem_prime_fd_to_handle(struct drm_device *dev,
790 struct drm_file *file_priv, int prime_fd,
791 uint32_t *handle)
792{
793 struct dma_buf *dma_buf;
794 struct drm_gem_object *obj;
795 int ret;
796
797 dma_buf = dma_buf_get(prime_fd);
798 if (IS_ERR(dma_buf))
799 return PTR_ERR(dma_buf);
800
801 mutex_lock(&file_priv->prime.lock);
802
803 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
804 dma_buf, handle);
805 if (ret == 0)
806 goto out_put;
807
808 /* never seen this one, need to import */
809 mutex_lock(&dev->object_name_lock);
810 obj = dev->driver->gem_prime_import(dev, dma_buf);
811 if (IS_ERR(obj)) {
812 ret = PTR_ERR(obj);
813 goto out_unlock;
814 }
815
816 if (obj->dma_buf) {
817 WARN_ON(obj->dma_buf != dma_buf);
818 } else {
819 obj->dma_buf = dma_buf;
820 get_dma_buf(dma_buf);
821 }
822
823 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
824 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
825 drm_gem_object_put_unlocked(obj);
826 if (ret)
827 goto out_put;
828
829 ret = drm_prime_add_buf_handle(&file_priv->prime,
830 dma_buf, *handle);
831 mutex_unlock(&file_priv->prime.lock);
832 if (ret)
833 goto fail;
834
835 dma_buf_put(dma_buf);
836
837 return 0;
838
839fail:
840 /* hmm, if driver attached, we are relying on the free-object path
841 * to detach.. which seems ok..
842 */
843 drm_gem_handle_delete(file_priv, *handle);
844 dma_buf_put(dma_buf);
845 return ret;
846
847out_unlock:
848 mutex_unlock(&dev->object_name_lock);
849out_put:
850 mutex_unlock(&file_priv->prime.lock);
851 dma_buf_put(dma_buf);
852 return ret;
853}
854EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
855
856int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
857 struct drm_file *file_priv)
858{
859 struct drm_prime_handle *args = data;
860
861 if (!drm_core_check_feature(dev, DRIVER_PRIME))
862 return -EINVAL;
863
864 if (!dev->driver->prime_handle_to_fd)
865 return -ENOSYS;
866
867 /* check flags are valid */
868 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
869 return -EINVAL;
870
871 return dev->driver->prime_handle_to_fd(dev, file_priv,
872 args->handle, args->flags, &args->fd);
873}
874
875int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
876 struct drm_file *file_priv)
877{
878 struct drm_prime_handle *args = data;
879
880 if (!drm_core_check_feature(dev, DRIVER_PRIME))
881 return -EINVAL;
882
883 if (!dev->driver->prime_fd_to_handle)
884 return -ENOSYS;
885
886 return dev->driver->prime_fd_to_handle(dev, file_priv,
887 args->fd, &args->handle);
888}
889
890/**
891 * drm_prime_pages_to_sg - converts a page array into an sg list
892 * @pages: pointer to the array of page pointers to convert
893 * @nr_pages: length of the page vector
894 *
895 * This helper creates an sg table object from a set of pages
896 * the driver is responsible for mapping the pages into the
897 * importers address space for use with dma_buf itself.
898 */
899struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
900{
901 struct sg_table *sg = NULL;
902 int ret;
903
904 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
905 if (!sg) {
906 ret = -ENOMEM;
907 goto out;
908 }
909
910 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
911 nr_pages << PAGE_SHIFT, GFP_KERNEL);
912 if (ret)
913 goto out;
914
915 return sg;
916out:
917 kfree(sg);
918 return ERR_PTR(ret);
919}
920EXPORT_SYMBOL(drm_prime_pages_to_sg);
921
922/**
923 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
924 * @sgt: scatter-gather table to convert
925 * @pages: optional array of page pointers to store the page array in
926 * @addrs: optional array to store the dma bus address of each page
927 * @max_entries: size of both the passed-in arrays
928 *
929 * Exports an sg table into an array of pages and addresses. This is currently
930 * required by the TTM driver in order to do correct fault handling.
931 */
932int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
933 dma_addr_t *addrs, int max_entries)
934{
935 unsigned count;
936 struct scatterlist *sg;
937 struct page *page;
938 u32 len, index;
939 dma_addr_t addr;
940
941 index = 0;
942 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
943 len = sg->length;
944 page = sg_page(sg);
945 addr = sg_dma_address(sg);
946
947 while (len > 0) {
948 if (WARN_ON(index >= max_entries))
949 return -1;
950 if (pages)
951 pages[index] = page;
952 if (addrs)
953 addrs[index] = addr;
954
955 page++;
956 addr += PAGE_SIZE;
957 len -= PAGE_SIZE;
958 index++;
959 }
960 }
961 return 0;
962}
963EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
964
965/**
966 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
967 * @obj: GEM object which was created from a dma-buf
968 * @sg: the sg-table which was pinned at import time
969 *
970 * This is the cleanup functions which GEM drivers need to call when they use
971 * @drm_gem_prime_import to import dma-bufs.
972 */
973void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
974{
975 struct dma_buf_attachment *attach;
976 struct dma_buf *dma_buf;
977 attach = obj->import_attach;
978 if (sg)
979 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
980 dma_buf = attach->dmabuf;
981 dma_buf_detach(attach->dmabuf, attach);
982 /* remove the reference */
983 dma_buf_put(dma_buf);
984}
985EXPORT_SYMBOL(drm_prime_gem_destroy);
986
987void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
988{
989 mutex_init(&prime_fpriv->lock);
990 prime_fpriv->dmabufs = RB_ROOT;
991 prime_fpriv->handles = RB_ROOT;
992}
993
994void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
995{
996 /* by now drm_gem_release should've made sure the list is empty */
997 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
998}