2 * Copyright © 2012 Red Hat
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
29 #include <linux/export.h>
30 #include <linux/dma-buf.h>
31 #include <linux/rbtree.h>
33 #include <drm/drm_drv.h>
34 #include <drm/drm_file.h>
35 #include <drm/drm_framebuffer.h>
36 #include <drm/drm_gem.h>
37 #include <drm/drm_prime.h>
39 #include "drm_internal.h"
42 * DOC: overview and lifetime rules
44 * Similar to GEM global names, PRIME file descriptors are also used to share
45 * buffer objects across processes. They offer additional security: as file
46 * descriptors must be explicitly sent over UNIX domain sockets to be shared
47 * between applications, they can't be guessed like the globally unique GEM
50 * Drivers that support the PRIME API implement the
51 * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
52 * GEM based drivers must use drm_gem_prime_handle_to_fd() and
53 * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
54 * actual driver interfaces is provided through the &drm_gem_object_funcs.export
55 * and &drm_driver.gem_prime_import hooks.
57 * &dma_buf_ops implementations for GEM drivers are all individually exported
58 * for drivers which need to overwrite or reimplement some of them.
60 * Reference Counting for GEM Drivers
61 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
63 * On the export the &dma_buf holds a reference to the exported buffer object,
64 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
65 * IOCTL, when it first calls &drm_gem_object_funcs.export
66 * and stores the exporting GEM object in the &dma_buf.priv field. This
67 * reference needs to be released when the final reference to the &dma_buf
68 * itself is dropped and its &dma_buf_ops.release function is called. For
69 * GEM-based drivers, the &dma_buf should be exported using
70 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
72 * Thus the chain of references always flows in one direction, avoiding loops:
73 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
74 * are the lookup caches for import and export. These are required to guarantee
75 * that any given object will always have only one uniqe userspace handle. This
76 * is required to allow userspace to detect duplicated imports, since some GEM
77 * drivers do fail command submissions if a given buffer object is listed more
78 * than once. These import and export caches in &drm_prime_file_private only
79 * retain a weak reference, which is cleaned up when the corresponding object is
82 * Self-importing: If userspace is using PRIME as a replacement for flink then
83 * it will get a fd->handle request for a GEM object that it created. Drivers
84 * should detect this situation and return back the underlying object from the
85 * dma-buf private. For GEM based drivers this is handled in
86 * drm_gem_prime_import() already.
89 struct drm_prime_member {
90 struct dma_buf *dma_buf;
93 struct rb_node dmabuf_rb;
94 struct rb_node handle_rb;
97 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
98 struct dma_buf *dma_buf, uint32_t handle)
100 struct drm_prime_member *member;
101 struct rb_node **p, *rb;
103 member = kmalloc(sizeof(*member), GFP_KERNEL);
107 get_dma_buf(dma_buf);
108 member->dma_buf = dma_buf;
109 member->handle = handle;
112 p = &prime_fpriv->dmabufs.rb_node;
114 struct drm_prime_member *pos;
117 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
118 if (dma_buf > pos->dma_buf)
123 rb_link_node(&member->dmabuf_rb, rb, p);
124 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
127 p = &prime_fpriv->handles.rb_node;
129 struct drm_prime_member *pos;
132 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
133 if (handle > pos->handle)
138 rb_link_node(&member->handle_rb, rb, p);
139 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
144 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
149 rb = prime_fpriv->handles.rb_node;
151 struct drm_prime_member *member;
153 member = rb_entry(rb, struct drm_prime_member, handle_rb);
154 if (member->handle == handle)
155 return member->dma_buf;
156 else if (member->handle < handle)
165 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
166 struct dma_buf *dma_buf,
171 rb = prime_fpriv->dmabufs.rb_node;
173 struct drm_prime_member *member;
175 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
176 if (member->dma_buf == dma_buf) {
177 *handle = member->handle;
179 } else if (member->dma_buf < dma_buf) {
189 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
190 struct dma_buf *dma_buf)
194 rb = prime_fpriv->dmabufs.rb_node;
196 struct drm_prime_member *member;
198 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
199 if (member->dma_buf == dma_buf) {
200 rb_erase(&member->handle_rb, &prime_fpriv->handles);
201 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
203 dma_buf_put(dma_buf);
206 } else if (member->dma_buf < dma_buf) {
214 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
216 mutex_init(&prime_fpriv->lock);
217 prime_fpriv->dmabufs = RB_ROOT;
218 prime_fpriv->handles = RB_ROOT;
221 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
223 /* by now drm_gem_release should've made sure the list is empty */
224 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
228 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
229 * @dev: parent device for the exported dmabuf
230 * @exp_info: the export information used by dma_buf_export()
232 * This wraps dma_buf_export() for use by generic GEM drivers that are using
233 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
234 * a reference to the &drm_device and the exported &drm_gem_object (stored in
235 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
237 * Returns the new dmabuf.
239 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
240 struct dma_buf_export_info *exp_info)
242 struct dma_buf *dma_buf;
244 dma_buf = dma_buf_export(exp_info);
249 drm_gem_object_get(exp_info->priv);
253 EXPORT_SYMBOL(drm_gem_dmabuf_export);
256 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
257 * @dma_buf: buffer to be released
259 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
260 * must use this in their &dma_buf_ops structure as the release callback.
261 * drm_gem_dmabuf_release() should be used in conjunction with
262 * drm_gem_dmabuf_export().
264 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
266 struct drm_gem_object *obj = dma_buf->priv;
267 struct drm_device *dev = obj->dev;
269 /* drop the reference on the export fd holds */
270 drm_gem_object_put_unlocked(obj);
274 EXPORT_SYMBOL(drm_gem_dmabuf_release);
277 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
278 * @dev: dev to export the buffer from
279 * @file_priv: drm file-private structure
280 * @prime_fd: fd id of the dma-buf which should be imported
281 * @handle: pointer to storage for the handle of the imported buffer object
283 * This is the PRIME import function which must be used mandatorily by GEM
284 * drivers to ensure correct lifetime management of the underlying GEM object.
285 * The actual importing of GEM object from the dma-buf is done through the
286 * &drm_driver.gem_prime_import driver callback.
288 * Returns 0 on success or a negative error code on failure.
290 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
291 struct drm_file *file_priv, int prime_fd,
294 struct dma_buf *dma_buf;
295 struct drm_gem_object *obj;
298 dma_buf = dma_buf_get(prime_fd);
300 return PTR_ERR(dma_buf);
302 mutex_lock(&file_priv->prime.lock);
304 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
309 /* never seen this one, need to import */
310 mutex_lock(&dev->object_name_lock);
311 if (dev->driver->gem_prime_import)
312 obj = dev->driver->gem_prime_import(dev, dma_buf);
314 obj = drm_gem_prime_import(dev, dma_buf);
321 WARN_ON(obj->dma_buf != dma_buf);
323 obj->dma_buf = dma_buf;
324 get_dma_buf(dma_buf);
327 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
328 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
329 drm_gem_object_put_unlocked(obj);
333 ret = drm_prime_add_buf_handle(&file_priv->prime,
335 mutex_unlock(&file_priv->prime.lock);
339 dma_buf_put(dma_buf);
344 /* hmm, if driver attached, we are relying on the free-object path
345 * to detach.. which seems ok..
347 drm_gem_handle_delete(file_priv, *handle);
348 dma_buf_put(dma_buf);
352 mutex_unlock(&dev->object_name_lock);
354 mutex_unlock(&file_priv->prime.lock);
355 dma_buf_put(dma_buf);
358 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
360 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
361 struct drm_file *file_priv)
363 struct drm_prime_handle *args = data;
365 if (!dev->driver->prime_fd_to_handle)
368 return dev->driver->prime_fd_to_handle(dev, file_priv,
369 args->fd, &args->handle);
372 static struct dma_buf *export_and_register_object(struct drm_device *dev,
373 struct drm_gem_object *obj,
376 struct dma_buf *dmabuf;
378 /* prevent races with concurrent gem_close. */
379 if (obj->handle_count == 0) {
380 dmabuf = ERR_PTR(-ENOENT);
384 if (obj->funcs && obj->funcs->export)
385 dmabuf = obj->funcs->export(obj, flags);
386 else if (dev->driver->gem_prime_export)
387 dmabuf = dev->driver->gem_prime_export(obj, flags);
389 dmabuf = drm_gem_prime_export(obj, flags);
390 if (IS_ERR(dmabuf)) {
391 /* normally the created dma-buf takes ownership of the ref,
392 * but if that fails then drop the ref
398 * Note that callers do not need to clean up the export cache
399 * since the check for obj->handle_count guarantees that someone
402 obj->dma_buf = dmabuf;
403 get_dma_buf(obj->dma_buf);
409 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
410 * @dev: dev to export the buffer from
411 * @file_priv: drm file-private structure
412 * @handle: buffer handle to export
413 * @flags: flags like DRM_CLOEXEC
414 * @prime_fd: pointer to storage for the fd id of the create dma-buf
416 * This is the PRIME export function which must be used mandatorily by GEM
417 * drivers to ensure correct lifetime management of the underlying GEM object.
418 * The actual exporting from GEM object to a dma-buf is done through the
419 * &drm_driver.gem_prime_export driver callback.
421 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
422 struct drm_file *file_priv, uint32_t handle,
426 struct drm_gem_object *obj;
428 struct dma_buf *dmabuf;
430 mutex_lock(&file_priv->prime.lock);
431 obj = drm_gem_object_lookup(file_priv, handle);
437 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
440 goto out_have_handle;
443 mutex_lock(&dev->object_name_lock);
444 /* re-export the original imported object */
445 if (obj->import_attach) {
446 dmabuf = obj->import_attach->dmabuf;
452 get_dma_buf(obj->dma_buf);
453 dmabuf = obj->dma_buf;
457 dmabuf = export_and_register_object(dev, obj, flags);
458 if (IS_ERR(dmabuf)) {
459 /* normally the created dma-buf takes ownership of the ref,
460 * but if that fails then drop the ref
462 ret = PTR_ERR(dmabuf);
463 mutex_unlock(&dev->object_name_lock);
469 * If we've exported this buffer then cheat and add it to the import list
470 * so we get the correct handle back. We must do this under the
471 * protection of dev->object_name_lock to ensure that a racing gem close
472 * ioctl doesn't miss to remove this buffer handle from the cache.
474 ret = drm_prime_add_buf_handle(&file_priv->prime,
476 mutex_unlock(&dev->object_name_lock);
478 goto fail_put_dmabuf;
481 ret = dma_buf_fd(dmabuf, flags);
483 * We must _not_ remove the buffer from the handle cache since the newly
484 * created dma buf is already linked in the global obj->dma_buf pointer,
485 * and that is invariant as long as a userspace gem handle exists.
486 * Closing the handle will clean out the cache anyway, so we don't leak.
489 goto fail_put_dmabuf;
500 drm_gem_object_put_unlocked(obj);
502 mutex_unlock(&file_priv->prime.lock);
506 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
508 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
509 struct drm_file *file_priv)
511 struct drm_prime_handle *args = data;
513 if (!dev->driver->prime_handle_to_fd)
516 /* check flags are valid */
517 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
520 return dev->driver->prime_handle_to_fd(dev, file_priv,
521 args->handle, args->flags, &args->fd);
527 * Drivers can implement &drm_gem_object_funcs.export and
528 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
529 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
530 * implement dma-buf support in terms of some lower-level helpers, which are
531 * again exported for drivers to use individually:
536 * Optional pinning of buffers is handled at dma-buf attach and detach time in
537 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
538 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
539 * &drm_gem_object_funcs.get_sg_table.
541 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
542 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
543 * drm_gem_dmabuf_mmap().
545 * Note that these export helpers can only be used if the underlying backing
546 * storage is fully coherent and either permanently pinned, or it is safe to pin
549 * FIXME: The underlying helper functions are named rather inconsistently.
554 * Importing dma-bufs using drm_gem_prime_import() relies on
555 * &drm_driver.gem_prime_import_sg_table.
557 * Note that similarly to the export helpers this permanently pins the
558 * underlying backing storage. Which is ok for scanout, but is not the best
559 * option for sharing lots of buffers for rendering.
563 * drm_gem_map_attach - dma_buf attach implementation for GEM
564 * @dma_buf: buffer to attach device to
565 * @attach: buffer attachment data
567 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
568 * used as the &dma_buf_ops.attach callback. Must be used together with
569 * drm_gem_map_detach().
571 * Returns 0 on success, negative error code on failure.
573 int drm_gem_map_attach(struct dma_buf *dma_buf,
574 struct dma_buf_attachment *attach)
576 struct drm_gem_object *obj = dma_buf->priv;
578 return drm_gem_pin(obj);
580 EXPORT_SYMBOL(drm_gem_map_attach);
583 * drm_gem_map_detach - dma_buf detach implementation for GEM
584 * @dma_buf: buffer to detach from
585 * @attach: attachment to be detached
587 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
588 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
589 * &dma_buf_ops.detach callback.
591 void drm_gem_map_detach(struct dma_buf *dma_buf,
592 struct dma_buf_attachment *attach)
594 struct drm_gem_object *obj = dma_buf->priv;
598 EXPORT_SYMBOL(drm_gem_map_detach);
601 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
602 * @attach: attachment whose scatterlist is to be returned
603 * @dir: direction of DMA transfer
605 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
606 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
607 * with drm_gem_unmap_dma_buf().
609 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
610 * on error. May return -EINTR if it is interrupted by a signal.
612 struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
613 enum dma_data_direction dir)
615 struct drm_gem_object *obj = attach->dmabuf->priv;
616 struct sg_table *sgt;
618 if (WARN_ON(dir == DMA_NONE))
619 return ERR_PTR(-EINVAL);
622 sgt = obj->funcs->get_sg_table(obj);
624 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
626 if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
627 DMA_ATTR_SKIP_CPU_SYNC)) {
630 sgt = ERR_PTR(-ENOMEM);
635 EXPORT_SYMBOL(drm_gem_map_dma_buf);
638 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
639 * @attach: attachment to unmap buffer from
640 * @sgt: scatterlist info of the buffer to unmap
641 * @dir: direction of DMA transfer
643 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
645 void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
646 struct sg_table *sgt,
647 enum dma_data_direction dir)
652 dma_unmap_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
653 DMA_ATTR_SKIP_CPU_SYNC);
657 EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
660 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
661 * @dma_buf: buffer to be mapped
663 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
664 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
666 * Returns the kernel virtual address or NULL on failure.
668 void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
670 struct drm_gem_object *obj = dma_buf->priv;
673 vaddr = drm_gem_vmap(obj);
679 EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
682 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
683 * @dma_buf: buffer to be unmapped
684 * @vaddr: the virtual address of the buffer
686 * Releases a kernel virtual mapping. This can be used as the
687 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
689 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
691 struct drm_gem_object *obj = dma_buf->priv;
693 drm_gem_vunmap(obj, vaddr);
695 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
698 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
700 * @vma: Virtual address range
702 * This function sets up a userspace mapping for PRIME exported buffers using
703 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
704 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
705 * called to set up the mapping.
707 * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
709 int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
711 struct drm_file *priv;
715 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
716 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
722 /* Used by drm_gem_mmap() to lookup the GEM object */
723 priv->minor = obj->dev->primary;
724 fil->private_data = priv;
726 ret = drm_vma_node_allow(&obj->vma_node, priv);
730 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
732 ret = obj->dev->driver->fops->mmap(fil, vma);
734 drm_vma_node_revoke(&obj->vma_node, priv);
741 EXPORT_SYMBOL(drm_gem_prime_mmap);
744 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
745 * @dma_buf: buffer to be mapped
746 * @vma: virtual address range
748 * Provides memory mapping for the buffer. This can be used as the
749 * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
750 * which should be set to drm_gem_prime_mmap().
752 * FIXME: There's really no point to this wrapper, drivers which need anything
753 * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
755 * Returns 0 on success or a negative error code on failure.
757 int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
759 struct drm_gem_object *obj = dma_buf->priv;
760 struct drm_device *dev = obj->dev;
762 if (!dev->driver->gem_prime_mmap)
765 return dev->driver->gem_prime_mmap(obj, vma);
767 EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
769 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
770 .cache_sgt_mapping = true,
771 .attach = drm_gem_map_attach,
772 .detach = drm_gem_map_detach,
773 .map_dma_buf = drm_gem_map_dma_buf,
774 .unmap_dma_buf = drm_gem_unmap_dma_buf,
775 .release = drm_gem_dmabuf_release,
776 .mmap = drm_gem_dmabuf_mmap,
777 .vmap = drm_gem_dmabuf_vmap,
778 .vunmap = drm_gem_dmabuf_vunmap,
782 * drm_prime_pages_to_sg - converts a page array into an sg list
783 * @pages: pointer to the array of page pointers to convert
784 * @nr_pages: length of the page vector
786 * This helper creates an sg table object from a set of pages
787 * the driver is responsible for mapping the pages into the
788 * importers address space for use with dma_buf itself.
790 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
792 struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
794 struct sg_table *sg = NULL;
797 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
803 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
804 nr_pages << PAGE_SHIFT, GFP_KERNEL);
813 EXPORT_SYMBOL(drm_prime_pages_to_sg);
816 * drm_gem_prime_export - helper library implementation of the export callback
817 * @obj: GEM object to export
818 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
820 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
821 * using the PRIME helpers. It is used as the default in
822 * drm_gem_prime_handle_to_fd().
824 struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
827 struct drm_device *dev = obj->dev;
828 struct dma_buf_export_info exp_info = {
829 .exp_name = KBUILD_MODNAME, /* white lie for debug */
830 .owner = dev->driver->fops->owner,
831 .ops = &drm_gem_prime_dmabuf_ops,
838 if (dev->driver->gem_prime_res_obj)
839 exp_info.resv = dev->driver->gem_prime_res_obj(obj);
841 return drm_gem_dmabuf_export(dev, &exp_info);
843 EXPORT_SYMBOL(drm_gem_prime_export);
846 * drm_gem_prime_import_dev - core implementation of the import callback
847 * @dev: drm_device to import into
848 * @dma_buf: dma-buf object to import
849 * @attach_dev: struct device to dma_buf attach
851 * This is the core of drm_gem_prime_import(). It's designed to be called by
852 * drivers who want to use a different device structure than &drm_device.dev for
853 * attaching via dma_buf. This function calls
854 * &drm_driver.gem_prime_import_sg_table internally.
856 * Drivers must arrange to call drm_prime_gem_destroy() from their
857 * &drm_gem_object_funcs.free hook when using this function.
859 struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
860 struct dma_buf *dma_buf,
861 struct device *attach_dev)
863 struct dma_buf_attachment *attach;
864 struct sg_table *sgt;
865 struct drm_gem_object *obj;
868 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
870 if (obj->dev == dev) {
872 * Importing dmabuf exported from out own gem increases
873 * refcount on gem itself instead of f_count of dmabuf.
875 drm_gem_object_get(obj);
880 if (!dev->driver->gem_prime_import_sg_table)
881 return ERR_PTR(-EINVAL);
883 attach = dma_buf_attach(dma_buf, attach_dev);
885 return ERR_CAST(attach);
887 get_dma_buf(dma_buf);
889 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
895 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
901 obj->import_attach = attach;
906 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
908 dma_buf_detach(dma_buf, attach);
909 dma_buf_put(dma_buf);
913 EXPORT_SYMBOL(drm_gem_prime_import_dev);
916 * drm_gem_prime_import - helper library implementation of the import callback
917 * @dev: drm_device to import into
918 * @dma_buf: dma-buf object to import
920 * This is the implementation of the gem_prime_import functions for GEM drivers
921 * using the PRIME helpers. Drivers can use this as their
922 * &drm_driver.gem_prime_import implementation. It is used as the default
923 * implementation in drm_gem_prime_fd_to_handle().
925 * Drivers must arrange to call drm_prime_gem_destroy() from their
926 * &drm_gem_object_funcs.free hook when using this function.
928 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
929 struct dma_buf *dma_buf)
931 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
933 EXPORT_SYMBOL(drm_gem_prime_import);
936 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
937 * @sgt: scatter-gather table to convert
938 * @pages: optional array of page pointers to store the page array in
939 * @addrs: optional array to store the dma bus address of each page
940 * @max_entries: size of both the passed-in arrays
942 * Exports an sg table into an array of pages and addresses. This is currently
943 * required by the TTM driver in order to do correct fault handling.
945 * Drivers can use this in their &drm_driver.gem_prime_import_sg_table
948 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
949 dma_addr_t *addrs, int max_entries)
952 struct scatterlist *sg;
958 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
961 addr = sg_dma_address(sg);
964 if (WARN_ON(index >= max_entries))
979 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
982 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
983 * @obj: GEM object which was created from a dma-buf
984 * @sg: the sg-table which was pinned at import time
986 * This is the cleanup functions which GEM drivers need to call when they use
987 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
989 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
991 struct dma_buf_attachment *attach;
992 struct dma_buf *dma_buf;
993 attach = obj->import_attach;
995 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
996 dma_buf = attach->dmabuf;
997 dma_buf_detach(attach->dmabuf, attach);
998 /* remove the reference */
999 dma_buf_put(dma_buf);
1001 EXPORT_SYMBOL(drm_prime_gem_destroy);