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_gem.h>
35 #include "drm_internal.h"
38 * DMA-BUF/GEM Object references and lifetime overview:
40 * On the export the dma_buf holds a reference to the exporting GEM
41 * object. It takes this reference in handle_to_fd_ioctl, when it
42 * first calls .prime_export and stores the exporting GEM object in
43 * the dma_buf priv. This reference is released when the dma_buf
44 * object goes away in the driver .release function.
46 * On the import the importing GEM object holds a reference to the
47 * dma_buf (which in turn holds a ref to the exporting GEM object).
48 * It takes that reference in the fd_to_handle ioctl.
49 * It calls dma_buf_get, creates an attachment to it and stores the
50 * attachment in the GEM object. When this attachment is destroyed
51 * when the imported object is destroyed, we remove the attachment
52 * and drop the reference to the dma_buf.
54 * Thus the chain of references always flows in one direction
55 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
57 * Self-importing: if userspace is using PRIME as a replacement for flink
58 * then it will get a fd->handle request for a GEM object that it created.
59 * Drivers should detect this situation and return back the gem object
60 * from the dma-buf private. Prime will do this automatically for drivers that
61 * use the drm_gem_prime_{import,export} helpers.
64 struct drm_prime_member {
65 struct dma_buf *dma_buf;
68 struct rb_node dmabuf_rb;
69 struct rb_node handle_rb;
72 struct drm_prime_attachment {
74 enum dma_data_direction dir;
77 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
78 struct dma_buf *dma_buf, uint32_t handle)
80 struct drm_prime_member *member;
81 struct rb_node **p, *rb;
83 member = kmalloc(sizeof(*member), M_DRM, GFP_KERNEL);
88 member->dma_buf = dma_buf;
89 member->handle = handle;
92 p = &prime_fpriv->dmabufs.rb_node;
94 struct drm_prime_member *pos;
97 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
98 if (dma_buf > pos->dma_buf)
103 rb_link_node(&member->dmabuf_rb, rb, p);
104 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
107 p = &prime_fpriv->handles.rb_node;
109 struct drm_prime_member *pos;
112 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
113 if (handle > pos->handle)
118 rb_link_node(&member->handle_rb, rb, p);
119 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
124 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
129 rb = prime_fpriv->handles.rb_node;
131 struct drm_prime_member *member;
133 member = rb_entry(rb, struct drm_prime_member, handle_rb);
134 if (member->handle == handle)
135 return member->dma_buf;
136 else if (member->handle < handle)
145 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
146 struct dma_buf *dma_buf,
151 rb = prime_fpriv->dmabufs.rb_node;
153 struct drm_prime_member *member;
155 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
156 if (member->dma_buf == dma_buf) {
157 *handle = member->handle;
159 } else if (member->dma_buf < dma_buf) {
169 static int drm_gem_map_attach(struct dma_buf *dma_buf,
170 struct device *target_dev,
171 struct dma_buf_attachment *attach)
173 struct drm_prime_attachment *prime_attach;
174 struct drm_gem_object *obj = dma_buf->priv;
175 struct drm_device *dev = obj->dev;
177 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
181 prime_attach->dir = DMA_NONE;
182 attach->priv = prime_attach;
184 if (!dev->driver->gem_prime_pin)
187 return dev->driver->gem_prime_pin(obj);
190 static void drm_gem_map_detach(struct dma_buf *dma_buf,
191 struct dma_buf_attachment *attach)
193 struct drm_prime_attachment *prime_attach = attach->priv;
194 struct drm_gem_object *obj = dma_buf->priv;
195 struct drm_device *dev = obj->dev;
196 struct sg_table *sgt;
198 if (dev->driver->gem_prime_unpin)
199 dev->driver->gem_prime_unpin(obj);
204 sgt = prime_attach->sgt;
206 if (prime_attach->dir != DMA_NONE)
207 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
217 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
218 struct dma_buf *dma_buf)
222 rb = prime_fpriv->dmabufs.rb_node;
224 struct drm_prime_member *member;
226 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
227 if (member->dma_buf == dma_buf) {
228 rb_erase(&member->handle_rb, &prime_fpriv->handles);
229 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
231 dma_buf_put(dma_buf);
234 } else if (member->dma_buf < dma_buf) {
242 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
243 enum dma_data_direction dir)
245 struct drm_prime_attachment *prime_attach = attach->priv;
246 struct drm_gem_object *obj = attach->dmabuf->priv;
247 struct sg_table *sgt;
249 if (WARN_ON(dir == DMA_NONE || !prime_attach))
250 return ERR_PTR(-EINVAL);
252 /* return the cached mapping when possible */
253 if (prime_attach->dir == dir)
254 return prime_attach->sgt;
257 * two mappings with different directions for the same attachment are
260 if (WARN_ON(prime_attach->dir != DMA_NONE))
261 return ERR_PTR(-EBUSY);
263 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
266 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
269 sgt = ERR_PTR(-ENOMEM);
271 prime_attach->sgt = sgt;
272 prime_attach->dir = dir;
279 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
280 struct sg_table *sgt,
281 enum dma_data_direction dir)
283 /* nothing to be done here */
287 * drm_gem_dmabuf_export - dma_buf export implementation for GEM
288 * @dev: parent device for the exported dmabuf
289 * @exp_info: the export information used by dma_buf_export()
291 * This wraps dma_buf_export() for use by generic GEM drivers that are using
292 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
293 * a reference to the &drm_device and the exported &drm_gem_object (stored in
294 * exp_info->priv) which is released by drm_gem_dmabuf_release().
296 * Returns the new dmabuf.
298 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
299 struct dma_buf_export_info *exp_info)
301 struct dma_buf *dma_buf;
303 dma_buf = dma_buf_export(exp_info);
308 drm_gem_object_reference(exp_info->priv);
312 EXPORT_SYMBOL(drm_gem_dmabuf_export);
315 * drm_gem_dmabuf_release - dma_buf release implementation for GEM
316 * @dma_buf: buffer to be released
318 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
319 * must use this in their dma_buf ops structure as the release callback.
320 * drm_gem_dmabuf_release() should be used in conjunction with
321 * drm_gem_dmabuf_export().
323 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
325 struct drm_gem_object *obj = dma_buf->priv;
326 struct drm_device *dev = obj->dev;
328 /* drop the reference on the export fd holds */
329 drm_gem_object_unreference_unlocked(obj);
333 EXPORT_SYMBOL(drm_gem_dmabuf_release);
335 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
337 struct drm_gem_object *obj = dma_buf->priv;
338 struct drm_device *dev = obj->dev;
340 return dev->driver->gem_prime_vmap(obj);
343 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
345 struct drm_gem_object *obj = dma_buf->priv;
346 struct drm_device *dev = obj->dev;
348 dev->driver->gem_prime_vunmap(obj, vaddr);
351 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
352 unsigned long page_num)
357 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
358 unsigned long page_num, void *addr)
362 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
363 unsigned long page_num)
368 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
369 unsigned long page_num, void *addr)
374 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
375 struct vm_area_struct *vma)
377 struct drm_gem_object *obj = dma_buf->priv;
378 struct drm_device *dev = obj->dev;
380 if (!dev->driver->gem_prime_mmap)
383 return dev->driver->gem_prime_mmap(obj, vma);
386 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
387 .attach = drm_gem_map_attach,
388 .detach = drm_gem_map_detach,
389 .map_dma_buf = drm_gem_map_dma_buf,
390 .unmap_dma_buf = drm_gem_unmap_dma_buf,
391 .release = drm_gem_dmabuf_release,
392 .kmap = drm_gem_dmabuf_kmap,
393 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
394 .kunmap = drm_gem_dmabuf_kunmap,
395 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
396 .mmap = drm_gem_dmabuf_mmap,
397 .vmap = drm_gem_dmabuf_vmap,
398 .vunmap = drm_gem_dmabuf_vunmap,
404 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
405 * simpler APIs by using the helper functions @drm_gem_prime_export and
406 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
407 * six lower-level driver callbacks:
411 * * @gem_prime_pin (optional): prepare a GEM object for exporting
412 * * @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
413 * * @gem_prime_vmap: vmap a buffer exported by your driver
414 * * @gem_prime_vunmap: vunmap a buffer exported by your driver
415 * * @gem_prime_mmap (optional): mmap a buffer exported by your driver
419 * * @gem_prime_import_sg_table (import): produce a GEM object from another
420 * driver's scatter/gather table
424 * drm_gem_prime_export - helper library implementation of the export callback
425 * @dev: drm_device to export from
426 * @obj: GEM object to export
427 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
429 * This is the implementation of the gem_prime_export functions for GEM drivers
430 * using the PRIME helpers.
432 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
433 struct drm_gem_object *obj,
436 struct dma_buf_export_info exp_info = {
438 .exp_name = KBUILD_MODNAME, /* white lie for debug */
439 .owner = dev->driver->fops->owner,
441 .ops = &drm_gem_prime_dmabuf_ops,
447 if (dev->driver->gem_prime_res_obj)
448 exp_info.resv = dev->driver->gem_prime_res_obj(obj);
450 return drm_gem_dmabuf_export(dev, &exp_info);
452 EXPORT_SYMBOL(drm_gem_prime_export);
454 static struct dma_buf *export_and_register_object(struct drm_device *dev,
455 struct drm_gem_object *obj,
458 struct dma_buf *dmabuf;
460 /* prevent races with concurrent gem_close. */
461 if (obj->handle_count == 0) {
462 dmabuf = ERR_PTR(-ENOENT);
466 dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
467 if (IS_ERR(dmabuf)) {
468 /* normally the created dma-buf takes ownership of the ref,
469 * but if that fails then drop the ref
475 * Note that callers do not need to clean up the export cache
476 * since the check for obj->handle_count guarantees that someone
479 obj->dma_buf = dmabuf;
480 get_dma_buf(obj->dma_buf);
486 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
487 * @dev: dev to export the buffer from
488 * @file_priv: drm file-private structure
489 * @handle: buffer handle to export
490 * @flags: flags like DRM_CLOEXEC
491 * @prime_fd: pointer to storage for the fd id of the create dma-buf
493 * This is the PRIME export function which must be used mandatorily by GEM
494 * drivers to ensure correct lifetime management of the underlying GEM object.
495 * The actual exporting from GEM object to a dma-buf is done through the
496 * gem_prime_export driver callback.
498 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
499 struct drm_file *file_priv, uint32_t handle,
503 struct drm_gem_object *obj;
505 struct dma_buf *dmabuf;
507 mutex_lock(&file_priv->prime.lock);
508 obj = drm_gem_object_lookup(file_priv, handle);
514 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
517 goto out_have_handle;
520 mutex_lock(&dev->object_name_lock);
521 /* re-export the original imported object */
522 if (obj->import_attach) {
523 dmabuf = obj->import_attach->dmabuf;
529 get_dma_buf(obj->dma_buf);
530 dmabuf = obj->dma_buf;
534 dmabuf = export_and_register_object(dev, obj, flags);
535 if (IS_ERR(dmabuf)) {
536 /* normally the created dma-buf takes ownership of the ref,
537 * but if that fails then drop the ref
539 ret = PTR_ERR(dmabuf);
540 mutex_unlock(&dev->object_name_lock);
546 * If we've exported this buffer then cheat and add it to the import list
547 * so we get the correct handle back. We must do this under the
548 * protection of dev->object_name_lock to ensure that a racing gem close
549 * ioctl doesn't miss to remove this buffer handle from the cache.
551 ret = drm_prime_add_buf_handle(&file_priv->prime,
553 mutex_unlock(&dev->object_name_lock);
555 goto fail_put_dmabuf;
558 ret = dma_buf_fd(dmabuf, flags);
560 * We must _not_ remove the buffer from the handle cache since the newly
561 * created dma buf is already linked in the global obj->dma_buf pointer,
562 * and that is invariant as long as a userspace gem handle exists.
563 * Closing the handle will clean out the cache anyway, so we don't leak.
566 goto fail_put_dmabuf;
577 drm_gem_object_unreference_unlocked(obj);
579 mutex_unlock(&file_priv->prime.lock);
583 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
586 * drm_gem_prime_import - helper library implementation of the import callback
587 * @dev: drm_device to import into
588 * @dma_buf: dma-buf object to import
590 * This is the implementation of the gem_prime_import functions for GEM drivers
591 * using the PRIME helpers.
593 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
594 struct dma_buf *dma_buf)
596 struct dma_buf_attachment *attach;
597 struct sg_table *sgt;
598 struct drm_gem_object *obj;
601 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
603 if (obj->dev == dev) {
605 * Importing dmabuf exported from out own gem increases
606 * refcount on gem itself instead of f_count of dmabuf.
608 drm_gem_object_reference(obj);
613 if (!dev->driver->gem_prime_import_sg_table)
614 return ERR_PTR(-EINVAL);
616 attach = dma_buf_attach(dma_buf, dev->dev);
618 return ERR_CAST(attach);
620 get_dma_buf(dma_buf);
622 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
628 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
634 obj->import_attach = attach;
639 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
641 dma_buf_detach(dma_buf, attach);
642 dma_buf_put(dma_buf);
646 EXPORT_SYMBOL(drm_gem_prime_import);
649 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
650 * @dev: dev to export the buffer from
651 * @file_priv: drm file-private structure
652 * @prime_fd: fd id of the dma-buf which should be imported
653 * @handle: pointer to storage for the handle of the imported buffer object
655 * This is the PRIME import function which must be used mandatorily by GEM
656 * drivers to ensure correct lifetime management of the underlying GEM object.
657 * The actual importing of GEM object from the dma-buf is done through the
658 * gem_import_export driver callback.
660 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
661 struct drm_file *file_priv, int prime_fd,
664 struct dma_buf *dma_buf;
665 struct drm_gem_object *obj;
668 dma_buf = dma_buf_get(prime_fd);
670 return PTR_ERR(dma_buf);
672 mutex_lock(&file_priv->prime.lock);
674 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
679 /* never seen this one, need to import */
680 mutex_lock(&dev->object_name_lock);
681 obj = dev->driver->gem_prime_import(dev, dma_buf);
688 WARN_ON(obj->dma_buf != dma_buf);
690 obj->dma_buf = dma_buf;
691 get_dma_buf(dma_buf);
694 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
695 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
696 drm_gem_object_unreference_unlocked(obj);
700 ret = drm_prime_add_buf_handle(&file_priv->prime,
702 mutex_unlock(&file_priv->prime.lock);
706 dma_buf_put(dma_buf);
711 /* hmm, if driver attached, we are relying on the free-object path
712 * to detach.. which seems ok..
714 drm_gem_handle_delete(file_priv, *handle);
715 dma_buf_put(dma_buf);
719 mutex_unlock(&dev->object_name_lock);
721 mutex_unlock(&file_priv->prime.lock);
722 dma_buf_put(dma_buf);
725 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
727 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
728 struct drm_file *file_priv)
730 struct drm_prime_handle *args = data;
732 if (!drm_core_check_feature(dev, DRIVER_PRIME))
735 if (!dev->driver->prime_handle_to_fd)
738 /* check flags are valid */
739 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
742 return dev->driver->prime_handle_to_fd(dev, file_priv,
743 args->handle, args->flags, &args->fd);
746 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
747 struct drm_file *file_priv)
749 struct drm_prime_handle *args = data;
751 if (!drm_core_check_feature(dev, DRIVER_PRIME))
754 if (!dev->driver->prime_fd_to_handle)
757 return dev->driver->prime_fd_to_handle(dev, file_priv,
758 args->fd, &args->handle);
762 * drm_prime_pages_to_sg - converts a page array into an sg list
763 * @pages: pointer to the array of page pointers to convert
764 * @nr_pages: length of the page vector
766 * This helper creates an sg table object from a set of pages
767 * the driver is responsible for mapping the pages into the
768 * importers address space for use with dma_buf itself.
770 struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
772 struct sg_table *sg = NULL;
775 sg = kmalloc(sizeof(struct sg_table), M_DRM, GFP_KERNEL);
781 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
782 nr_pages << PAGE_SHIFT, GFP_KERNEL);
791 EXPORT_SYMBOL(drm_prime_pages_to_sg);
794 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
795 * @sgt: scatter-gather table to convert
796 * @pages: array of page pointers to store the page array in
797 * @addrs: optional array to store the dma bus address of each page
798 * @max_pages: size of both the passed-in arrays
800 * Exports an sg table into an array of pages and addresses. This is currently
801 * required by the TTM driver in order to do correct fault handling.
803 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
804 dma_addr_t *addrs, int max_pages)
807 struct scatterlist *sg;
814 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
817 addr = sg_dma_address(sg);
820 if (WARN_ON(pg_index >= max_pages))
822 pages[pg_index] = page;
824 addrs[pg_index] = addr;
834 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
837 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
838 * @obj: GEM object which was created from a dma-buf
839 * @sg: the sg-table which was pinned at import time
841 * This is the cleanup functions which GEM drivers need to call when they use
842 * @drm_gem_prime_import to import dma-bufs.
844 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
846 struct dma_buf_attachment *attach;
847 struct dma_buf *dma_buf;
848 attach = obj->import_attach;
850 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
851 dma_buf = attach->dmabuf;
852 dma_buf_detach(attach->dmabuf, attach);
853 /* remove the reference */
854 dma_buf_put(dma_buf);
856 EXPORT_SYMBOL(drm_prime_gem_destroy);
858 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
860 lockinit(&prime_fpriv->lock, "drmpfpl", 0, LK_CANRECURSE);
861 prime_fpriv->dmabufs = LINUX_RB_ROOT;
862 prime_fpriv->handles = LINUX_RB_ROOT;
865 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
867 /* by now drm_gem_release should've made sure the list is empty */
868 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));