Loading...
Note: File does not exist in v3.1.
1/*
2 * Framework for buffer objects that can be shared across devices/subsystems.
3 *
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Author: Sumit Semwal <sumit.semwal@ti.com>
6 *
7 * Many thanks to linaro-mm-sig list, and specially
8 * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
9 * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
10 * refining of this idea.
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License version 2 as published by
14 * the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * more details.
20 *
21 * You should have received a copy of the GNU General Public License along with
22 * this program. If not, see <http://www.gnu.org/licenses/>.
23 */
24
25#include <linux/fs.h>
26#include <linux/slab.h>
27#include <linux/dma-buf.h>
28#include <linux/dma-fence.h>
29#include <linux/anon_inodes.h>
30#include <linux/export.h>
31#include <linux/debugfs.h>
32#include <linux/module.h>
33#include <linux/seq_file.h>
34#include <linux/poll.h>
35#include <linux/reservation.h>
36#include <linux/mm.h>
37
38#include <uapi/linux/dma-buf.h>
39
40static inline int is_dma_buf_file(struct file *);
41
42struct dma_buf_list {
43 struct list_head head;
44 struct mutex lock;
45};
46
47static struct dma_buf_list db_list;
48
49static int dma_buf_release(struct inode *inode, struct file *file)
50{
51 struct dma_buf *dmabuf;
52
53 if (!is_dma_buf_file(file))
54 return -EINVAL;
55
56 dmabuf = file->private_data;
57
58 BUG_ON(dmabuf->vmapping_counter);
59
60 /*
61 * Any fences that a dma-buf poll can wait on should be signaled
62 * before releasing dma-buf. This is the responsibility of each
63 * driver that uses the reservation objects.
64 *
65 * If you hit this BUG() it means someone dropped their ref to the
66 * dma-buf while still having pending operation to the buffer.
67 */
68 BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
69
70 dmabuf->ops->release(dmabuf);
71
72 mutex_lock(&db_list.lock);
73 list_del(&dmabuf->list_node);
74 mutex_unlock(&db_list.lock);
75
76 if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
77 reservation_object_fini(dmabuf->resv);
78
79 module_put(dmabuf->owner);
80 kfree(dmabuf);
81 return 0;
82}
83
84static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
85{
86 struct dma_buf *dmabuf;
87
88 if (!is_dma_buf_file(file))
89 return -EINVAL;
90
91 dmabuf = file->private_data;
92
93 /* check for overflowing the buffer's size */
94 if (vma->vm_pgoff + vma_pages(vma) >
95 dmabuf->size >> PAGE_SHIFT)
96 return -EINVAL;
97
98 return dmabuf->ops->mmap(dmabuf, vma);
99}
100
101static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
102{
103 struct dma_buf *dmabuf;
104 loff_t base;
105
106 if (!is_dma_buf_file(file))
107 return -EBADF;
108
109 dmabuf = file->private_data;
110
111 /* only support discovering the end of the buffer,
112 but also allow SEEK_SET to maintain the idiomatic
113 SEEK_END(0), SEEK_CUR(0) pattern */
114 if (whence == SEEK_END)
115 base = dmabuf->size;
116 else if (whence == SEEK_SET)
117 base = 0;
118 else
119 return -EINVAL;
120
121 if (offset != 0)
122 return -EINVAL;
123
124 return base + offset;
125}
126
127static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
128{
129 struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
130 unsigned long flags;
131
132 spin_lock_irqsave(&dcb->poll->lock, flags);
133 wake_up_locked_poll(dcb->poll, dcb->active);
134 dcb->active = 0;
135 spin_unlock_irqrestore(&dcb->poll->lock, flags);
136}
137
138static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
139{
140 struct dma_buf *dmabuf;
141 struct reservation_object *resv;
142 struct reservation_object_list *fobj;
143 struct dma_fence *fence_excl;
144 unsigned long events;
145 unsigned shared_count, seq;
146
147 dmabuf = file->private_data;
148 if (!dmabuf || !dmabuf->resv)
149 return POLLERR;
150
151 resv = dmabuf->resv;
152
153 poll_wait(file, &dmabuf->poll, poll);
154
155 events = poll_requested_events(poll) & (POLLIN | POLLOUT);
156 if (!events)
157 return 0;
158
159retry:
160 seq = read_seqcount_begin(&resv->seq);
161 rcu_read_lock();
162
163 fobj = rcu_dereference(resv->fence);
164 if (fobj)
165 shared_count = fobj->shared_count;
166 else
167 shared_count = 0;
168 fence_excl = rcu_dereference(resv->fence_excl);
169 if (read_seqcount_retry(&resv->seq, seq)) {
170 rcu_read_unlock();
171 goto retry;
172 }
173
174 if (fence_excl && (!(events & POLLOUT) || shared_count == 0)) {
175 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl;
176 unsigned long pevents = POLLIN;
177
178 if (shared_count == 0)
179 pevents |= POLLOUT;
180
181 spin_lock_irq(&dmabuf->poll.lock);
182 if (dcb->active) {
183 dcb->active |= pevents;
184 events &= ~pevents;
185 } else
186 dcb->active = pevents;
187 spin_unlock_irq(&dmabuf->poll.lock);
188
189 if (events & pevents) {
190 if (!dma_fence_get_rcu(fence_excl)) {
191 /* force a recheck */
192 events &= ~pevents;
193 dma_buf_poll_cb(NULL, &dcb->cb);
194 } else if (!dma_fence_add_callback(fence_excl, &dcb->cb,
195 dma_buf_poll_cb)) {
196 events &= ~pevents;
197 dma_fence_put(fence_excl);
198 } else {
199 /*
200 * No callback queued, wake up any additional
201 * waiters.
202 */
203 dma_fence_put(fence_excl);
204 dma_buf_poll_cb(NULL, &dcb->cb);
205 }
206 }
207 }
208
209 if ((events & POLLOUT) && shared_count > 0) {
210 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
211 int i;
212
213 /* Only queue a new callback if no event has fired yet */
214 spin_lock_irq(&dmabuf->poll.lock);
215 if (dcb->active)
216 events &= ~POLLOUT;
217 else
218 dcb->active = POLLOUT;
219 spin_unlock_irq(&dmabuf->poll.lock);
220
221 if (!(events & POLLOUT))
222 goto out;
223
224 for (i = 0; i < shared_count; ++i) {
225 struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
226
227 if (!dma_fence_get_rcu(fence)) {
228 /*
229 * fence refcount dropped to zero, this means
230 * that fobj has been freed
231 *
232 * call dma_buf_poll_cb and force a recheck!
233 */
234 events &= ~POLLOUT;
235 dma_buf_poll_cb(NULL, &dcb->cb);
236 break;
237 }
238 if (!dma_fence_add_callback(fence, &dcb->cb,
239 dma_buf_poll_cb)) {
240 dma_fence_put(fence);
241 events &= ~POLLOUT;
242 break;
243 }
244 dma_fence_put(fence);
245 }
246
247 /* No callback queued, wake up any additional waiters. */
248 if (i == shared_count)
249 dma_buf_poll_cb(NULL, &dcb->cb);
250 }
251
252out:
253 rcu_read_unlock();
254 return events;
255}
256
257static long dma_buf_ioctl(struct file *file,
258 unsigned int cmd, unsigned long arg)
259{
260 struct dma_buf *dmabuf;
261 struct dma_buf_sync sync;
262 enum dma_data_direction direction;
263 int ret;
264
265 dmabuf = file->private_data;
266
267 switch (cmd) {
268 case DMA_BUF_IOCTL_SYNC:
269 if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
270 return -EFAULT;
271
272 if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
273 return -EINVAL;
274
275 switch (sync.flags & DMA_BUF_SYNC_RW) {
276 case DMA_BUF_SYNC_READ:
277 direction = DMA_FROM_DEVICE;
278 break;
279 case DMA_BUF_SYNC_WRITE:
280 direction = DMA_TO_DEVICE;
281 break;
282 case DMA_BUF_SYNC_RW:
283 direction = DMA_BIDIRECTIONAL;
284 break;
285 default:
286 return -EINVAL;
287 }
288
289 if (sync.flags & DMA_BUF_SYNC_END)
290 ret = dma_buf_end_cpu_access(dmabuf, direction);
291 else
292 ret = dma_buf_begin_cpu_access(dmabuf, direction);
293
294 return ret;
295 default:
296 return -ENOTTY;
297 }
298}
299
300static const struct file_operations dma_buf_fops = {
301 .release = dma_buf_release,
302 .mmap = dma_buf_mmap_internal,
303 .llseek = dma_buf_llseek,
304 .poll = dma_buf_poll,
305 .unlocked_ioctl = dma_buf_ioctl,
306#ifdef CONFIG_COMPAT
307 .compat_ioctl = dma_buf_ioctl,
308#endif
309};
310
311/*
312 * is_dma_buf_file - Check if struct file* is associated with dma_buf
313 */
314static inline int is_dma_buf_file(struct file *file)
315{
316 return file->f_op == &dma_buf_fops;
317}
318
319/**
320 * dma_buf_export - Creates a new dma_buf, and associates an anon file
321 * with this buffer, so it can be exported.
322 * Also connect the allocator specific data and ops to the buffer.
323 * Additionally, provide a name string for exporter; useful in debugging.
324 *
325 * @exp_info: [in] holds all the export related information provided
326 * by the exporter. see struct dma_buf_export_info
327 * for further details.
328 *
329 * Returns, on success, a newly created dma_buf object, which wraps the
330 * supplied private data and operations for dma_buf_ops. On either missing
331 * ops, or error in allocating struct dma_buf, will return negative error.
332 *
333 */
334struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
335{
336 struct dma_buf *dmabuf;
337 struct reservation_object *resv = exp_info->resv;
338 struct file *file;
339 size_t alloc_size = sizeof(struct dma_buf);
340 int ret;
341
342 if (!exp_info->resv)
343 alloc_size += sizeof(struct reservation_object);
344 else
345 /* prevent &dma_buf[1] == dma_buf->resv */
346 alloc_size += 1;
347
348 if (WARN_ON(!exp_info->priv
349 || !exp_info->ops
350 || !exp_info->ops->map_dma_buf
351 || !exp_info->ops->unmap_dma_buf
352 || !exp_info->ops->release
353 || !exp_info->ops->kmap_atomic
354 || !exp_info->ops->kmap
355 || !exp_info->ops->mmap)) {
356 return ERR_PTR(-EINVAL);
357 }
358
359 if (!try_module_get(exp_info->owner))
360 return ERR_PTR(-ENOENT);
361
362 dmabuf = kzalloc(alloc_size, GFP_KERNEL);
363 if (!dmabuf) {
364 ret = -ENOMEM;
365 goto err_module;
366 }
367
368 dmabuf->priv = exp_info->priv;
369 dmabuf->ops = exp_info->ops;
370 dmabuf->size = exp_info->size;
371 dmabuf->exp_name = exp_info->exp_name;
372 dmabuf->owner = exp_info->owner;
373 init_waitqueue_head(&dmabuf->poll);
374 dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
375 dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
376
377 if (!resv) {
378 resv = (struct reservation_object *)&dmabuf[1];
379 reservation_object_init(resv);
380 }
381 dmabuf->resv = resv;
382
383 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
384 exp_info->flags);
385 if (IS_ERR(file)) {
386 ret = PTR_ERR(file);
387 goto err_dmabuf;
388 }
389
390 file->f_mode |= FMODE_LSEEK;
391 dmabuf->file = file;
392
393 mutex_init(&dmabuf->lock);
394 INIT_LIST_HEAD(&dmabuf->attachments);
395
396 mutex_lock(&db_list.lock);
397 list_add(&dmabuf->list_node, &db_list.head);
398 mutex_unlock(&db_list.lock);
399
400 return dmabuf;
401
402err_dmabuf:
403 kfree(dmabuf);
404err_module:
405 module_put(exp_info->owner);
406 return ERR_PTR(ret);
407}
408EXPORT_SYMBOL_GPL(dma_buf_export);
409
410/**
411 * dma_buf_fd - returns a file descriptor for the given dma_buf
412 * @dmabuf: [in] pointer to dma_buf for which fd is required.
413 * @flags: [in] flags to give to fd
414 *
415 * On success, returns an associated 'fd'. Else, returns error.
416 */
417int dma_buf_fd(struct dma_buf *dmabuf, int flags)
418{
419 int fd;
420
421 if (!dmabuf || !dmabuf->file)
422 return -EINVAL;
423
424 fd = get_unused_fd_flags(flags);
425 if (fd < 0)
426 return fd;
427
428 fd_install(fd, dmabuf->file);
429
430 return fd;
431}
432EXPORT_SYMBOL_GPL(dma_buf_fd);
433
434/**
435 * dma_buf_get - returns the dma_buf structure related to an fd
436 * @fd: [in] fd associated with the dma_buf to be returned
437 *
438 * On success, returns the dma_buf structure associated with an fd; uses
439 * file's refcounting done by fget to increase refcount. returns ERR_PTR
440 * otherwise.
441 */
442struct dma_buf *dma_buf_get(int fd)
443{
444 struct file *file;
445
446 file = fget(fd);
447
448 if (!file)
449 return ERR_PTR(-EBADF);
450
451 if (!is_dma_buf_file(file)) {
452 fput(file);
453 return ERR_PTR(-EINVAL);
454 }
455
456 return file->private_data;
457}
458EXPORT_SYMBOL_GPL(dma_buf_get);
459
460/**
461 * dma_buf_put - decreases refcount of the buffer
462 * @dmabuf: [in] buffer to reduce refcount of
463 *
464 * Uses file's refcounting done implicitly by fput()
465 */
466void dma_buf_put(struct dma_buf *dmabuf)
467{
468 if (WARN_ON(!dmabuf || !dmabuf->file))
469 return;
470
471 fput(dmabuf->file);
472}
473EXPORT_SYMBOL_GPL(dma_buf_put);
474
475/**
476 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
477 * calls attach() of dma_buf_ops to allow device-specific attach functionality
478 * @dmabuf: [in] buffer to attach device to.
479 * @dev: [in] device to be attached.
480 *
481 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
482 * error.
483 */
484struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
485 struct device *dev)
486{
487 struct dma_buf_attachment *attach;
488 int ret;
489
490 if (WARN_ON(!dmabuf || !dev))
491 return ERR_PTR(-EINVAL);
492
493 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
494 if (attach == NULL)
495 return ERR_PTR(-ENOMEM);
496
497 attach->dev = dev;
498 attach->dmabuf = dmabuf;
499
500 mutex_lock(&dmabuf->lock);
501
502 if (dmabuf->ops->attach) {
503 ret = dmabuf->ops->attach(dmabuf, dev, attach);
504 if (ret)
505 goto err_attach;
506 }
507 list_add(&attach->node, &dmabuf->attachments);
508
509 mutex_unlock(&dmabuf->lock);
510 return attach;
511
512err_attach:
513 kfree(attach);
514 mutex_unlock(&dmabuf->lock);
515 return ERR_PTR(ret);
516}
517EXPORT_SYMBOL_GPL(dma_buf_attach);
518
519/**
520 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
521 * optionally calls detach() of dma_buf_ops for device-specific detach
522 * @dmabuf: [in] buffer to detach from.
523 * @attach: [in] attachment to be detached; is free'd after this call.
524 *
525 */
526void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
527{
528 if (WARN_ON(!dmabuf || !attach))
529 return;
530
531 mutex_lock(&dmabuf->lock);
532 list_del(&attach->node);
533 if (dmabuf->ops->detach)
534 dmabuf->ops->detach(dmabuf, attach);
535
536 mutex_unlock(&dmabuf->lock);
537 kfree(attach);
538}
539EXPORT_SYMBOL_GPL(dma_buf_detach);
540
541/**
542 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
543 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
544 * dma_buf_ops.
545 * @attach: [in] attachment whose scatterlist is to be returned
546 * @direction: [in] direction of DMA transfer
547 *
548 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
549 * on error.
550 */
551struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
552 enum dma_data_direction direction)
553{
554 struct sg_table *sg_table = ERR_PTR(-EINVAL);
555
556 might_sleep();
557
558 if (WARN_ON(!attach || !attach->dmabuf))
559 return ERR_PTR(-EINVAL);
560
561 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
562 if (!sg_table)
563 sg_table = ERR_PTR(-ENOMEM);
564
565 return sg_table;
566}
567EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
568
569/**
570 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
571 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
572 * dma_buf_ops.
573 * @attach: [in] attachment to unmap buffer from
574 * @sg_table: [in] scatterlist info of the buffer to unmap
575 * @direction: [in] direction of DMA transfer
576 *
577 */
578void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
579 struct sg_table *sg_table,
580 enum dma_data_direction direction)
581{
582 might_sleep();
583
584 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
585 return;
586
587 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
588 direction);
589}
590EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
591
592static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
593 enum dma_data_direction direction)
594{
595 bool write = (direction == DMA_BIDIRECTIONAL ||
596 direction == DMA_TO_DEVICE);
597 struct reservation_object *resv = dmabuf->resv;
598 long ret;
599
600 /* Wait on any implicit rendering fences */
601 ret = reservation_object_wait_timeout_rcu(resv, write, true,
602 MAX_SCHEDULE_TIMEOUT);
603 if (ret < 0)
604 return ret;
605
606 return 0;
607}
608
609/**
610 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
611 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
612 * preparations. Coherency is only guaranteed in the specified range for the
613 * specified access direction.
614 * @dmabuf: [in] buffer to prepare cpu access for.
615 * @direction: [in] length of range for cpu access.
616 *
617 * Can return negative error values, returns 0 on success.
618 */
619int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
620 enum dma_data_direction direction)
621{
622 int ret = 0;
623
624 if (WARN_ON(!dmabuf))
625 return -EINVAL;
626
627 if (dmabuf->ops->begin_cpu_access)
628 ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
629
630 /* Ensure that all fences are waited upon - but we first allow
631 * the native handler the chance to do so more efficiently if it
632 * chooses. A double invocation here will be reasonably cheap no-op.
633 */
634 if (ret == 0)
635 ret = __dma_buf_begin_cpu_access(dmabuf, direction);
636
637 return ret;
638}
639EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
640
641/**
642 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
643 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
644 * actions. Coherency is only guaranteed in the specified range for the
645 * specified access direction.
646 * @dmabuf: [in] buffer to complete cpu access for.
647 * @direction: [in] length of range for cpu access.
648 *
649 * Can return negative error values, returns 0 on success.
650 */
651int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
652 enum dma_data_direction direction)
653{
654 int ret = 0;
655
656 WARN_ON(!dmabuf);
657
658 if (dmabuf->ops->end_cpu_access)
659 ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
660
661 return ret;
662}
663EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
664
665/**
666 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
667 * space. The same restrictions as for kmap_atomic and friends apply.
668 * @dmabuf: [in] buffer to map page from.
669 * @page_num: [in] page in PAGE_SIZE units to map.
670 *
671 * This call must always succeed, any necessary preparations that might fail
672 * need to be done in begin_cpu_access.
673 */
674void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
675{
676 WARN_ON(!dmabuf);
677
678 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
679}
680EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
681
682/**
683 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
684 * @dmabuf: [in] buffer to unmap page from.
685 * @page_num: [in] page in PAGE_SIZE units to unmap.
686 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
687 *
688 * This call must always succeed.
689 */
690void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
691 void *vaddr)
692{
693 WARN_ON(!dmabuf);
694
695 if (dmabuf->ops->kunmap_atomic)
696 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
697}
698EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
699
700/**
701 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
702 * same restrictions as for kmap and friends apply.
703 * @dmabuf: [in] buffer to map page from.
704 * @page_num: [in] page in PAGE_SIZE units to map.
705 *
706 * This call must always succeed, any necessary preparations that might fail
707 * need to be done in begin_cpu_access.
708 */
709void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
710{
711 WARN_ON(!dmabuf);
712
713 return dmabuf->ops->kmap(dmabuf, page_num);
714}
715EXPORT_SYMBOL_GPL(dma_buf_kmap);
716
717/**
718 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
719 * @dmabuf: [in] buffer to unmap page from.
720 * @page_num: [in] page in PAGE_SIZE units to unmap.
721 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
722 *
723 * This call must always succeed.
724 */
725void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
726 void *vaddr)
727{
728 WARN_ON(!dmabuf);
729
730 if (dmabuf->ops->kunmap)
731 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
732}
733EXPORT_SYMBOL_GPL(dma_buf_kunmap);
734
735
736/**
737 * dma_buf_mmap - Setup up a userspace mmap with the given vma
738 * @dmabuf: [in] buffer that should back the vma
739 * @vma: [in] vma for the mmap
740 * @pgoff: [in] offset in pages where this mmap should start within the
741 * dma-buf buffer.
742 *
743 * This function adjusts the passed in vma so that it points at the file of the
744 * dma_buf operation. It also adjusts the starting pgoff and does bounds
745 * checking on the size of the vma. Then it calls the exporters mmap function to
746 * set up the mapping.
747 *
748 * Can return negative error values, returns 0 on success.
749 */
750int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
751 unsigned long pgoff)
752{
753 struct file *oldfile;
754 int ret;
755
756 if (WARN_ON(!dmabuf || !vma))
757 return -EINVAL;
758
759 /* check for offset overflow */
760 if (pgoff + vma_pages(vma) < pgoff)
761 return -EOVERFLOW;
762
763 /* check for overflowing the buffer's size */
764 if (pgoff + vma_pages(vma) >
765 dmabuf->size >> PAGE_SHIFT)
766 return -EINVAL;
767
768 /* readjust the vma */
769 get_file(dmabuf->file);
770 oldfile = vma->vm_file;
771 vma->vm_file = dmabuf->file;
772 vma->vm_pgoff = pgoff;
773
774 ret = dmabuf->ops->mmap(dmabuf, vma);
775 if (ret) {
776 /* restore old parameters on failure */
777 vma->vm_file = oldfile;
778 fput(dmabuf->file);
779 } else {
780 if (oldfile)
781 fput(oldfile);
782 }
783 return ret;
784
785}
786EXPORT_SYMBOL_GPL(dma_buf_mmap);
787
788/**
789 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
790 * address space. Same restrictions as for vmap and friends apply.
791 * @dmabuf: [in] buffer to vmap
792 *
793 * This call may fail due to lack of virtual mapping address space.
794 * These calls are optional in drivers. The intended use for them
795 * is for mapping objects linear in kernel space for high use objects.
796 * Please attempt to use kmap/kunmap before thinking about these interfaces.
797 *
798 * Returns NULL on error.
799 */
800void *dma_buf_vmap(struct dma_buf *dmabuf)
801{
802 void *ptr;
803
804 if (WARN_ON(!dmabuf))
805 return NULL;
806
807 if (!dmabuf->ops->vmap)
808 return NULL;
809
810 mutex_lock(&dmabuf->lock);
811 if (dmabuf->vmapping_counter) {
812 dmabuf->vmapping_counter++;
813 BUG_ON(!dmabuf->vmap_ptr);
814 ptr = dmabuf->vmap_ptr;
815 goto out_unlock;
816 }
817
818 BUG_ON(dmabuf->vmap_ptr);
819
820 ptr = dmabuf->ops->vmap(dmabuf);
821 if (WARN_ON_ONCE(IS_ERR(ptr)))
822 ptr = NULL;
823 if (!ptr)
824 goto out_unlock;
825
826 dmabuf->vmap_ptr = ptr;
827 dmabuf->vmapping_counter = 1;
828
829out_unlock:
830 mutex_unlock(&dmabuf->lock);
831 return ptr;
832}
833EXPORT_SYMBOL_GPL(dma_buf_vmap);
834
835/**
836 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
837 * @dmabuf: [in] buffer to vunmap
838 * @vaddr: [in] vmap to vunmap
839 */
840void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
841{
842 if (WARN_ON(!dmabuf))
843 return;
844
845 BUG_ON(!dmabuf->vmap_ptr);
846 BUG_ON(dmabuf->vmapping_counter == 0);
847 BUG_ON(dmabuf->vmap_ptr != vaddr);
848
849 mutex_lock(&dmabuf->lock);
850 if (--dmabuf->vmapping_counter == 0) {
851 if (dmabuf->ops->vunmap)
852 dmabuf->ops->vunmap(dmabuf, vaddr);
853 dmabuf->vmap_ptr = NULL;
854 }
855 mutex_unlock(&dmabuf->lock);
856}
857EXPORT_SYMBOL_GPL(dma_buf_vunmap);
858
859#ifdef CONFIG_DEBUG_FS
860static int dma_buf_debug_show(struct seq_file *s, void *unused)
861{
862 int ret;
863 struct dma_buf *buf_obj;
864 struct dma_buf_attachment *attach_obj;
865 int count = 0, attach_count;
866 size_t size = 0;
867
868 ret = mutex_lock_interruptible(&db_list.lock);
869
870 if (ret)
871 return ret;
872
873 seq_puts(s, "\nDma-buf Objects:\n");
874 seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
875
876 list_for_each_entry(buf_obj, &db_list.head, list_node) {
877 ret = mutex_lock_interruptible(&buf_obj->lock);
878
879 if (ret) {
880 seq_puts(s,
881 "\tERROR locking buffer object: skipping\n");
882 continue;
883 }
884
885 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
886 buf_obj->size,
887 buf_obj->file->f_flags, buf_obj->file->f_mode,
888 file_count(buf_obj->file),
889 buf_obj->exp_name);
890
891 seq_puts(s, "\tAttached Devices:\n");
892 attach_count = 0;
893
894 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
895 seq_puts(s, "\t");
896
897 seq_printf(s, "%s\n", dev_name(attach_obj->dev));
898 attach_count++;
899 }
900
901 seq_printf(s, "Total %d devices attached\n\n",
902 attach_count);
903
904 count++;
905 size += buf_obj->size;
906 mutex_unlock(&buf_obj->lock);
907 }
908
909 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
910
911 mutex_unlock(&db_list.lock);
912 return 0;
913}
914
915static int dma_buf_debug_open(struct inode *inode, struct file *file)
916{
917 return single_open(file, dma_buf_debug_show, NULL);
918}
919
920static const struct file_operations dma_buf_debug_fops = {
921 .open = dma_buf_debug_open,
922 .read = seq_read,
923 .llseek = seq_lseek,
924 .release = single_release,
925};
926
927static struct dentry *dma_buf_debugfs_dir;
928
929static int dma_buf_init_debugfs(void)
930{
931 struct dentry *d;
932 int err = 0;
933
934 d = debugfs_create_dir("dma_buf", NULL);
935 if (IS_ERR(d))
936 return PTR_ERR(d);
937
938 dma_buf_debugfs_dir = d;
939
940 d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
941 NULL, &dma_buf_debug_fops);
942 if (IS_ERR(d)) {
943 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
944 debugfs_remove_recursive(dma_buf_debugfs_dir);
945 dma_buf_debugfs_dir = NULL;
946 err = PTR_ERR(d);
947 }
948
949 return err;
950}
951
952static void dma_buf_uninit_debugfs(void)
953{
954 if (dma_buf_debugfs_dir)
955 debugfs_remove_recursive(dma_buf_debugfs_dir);
956}
957#else
958static inline int dma_buf_init_debugfs(void)
959{
960 return 0;
961}
962static inline void dma_buf_uninit_debugfs(void)
963{
964}
965#endif
966
967static int __init dma_buf_init(void)
968{
969 mutex_init(&db_list.lock);
970 INIT_LIST_HEAD(&db_list.head);
971 dma_buf_init_debugfs();
972 return 0;
973}
974subsys_initcall(dma_buf_init);
975
976static void __exit dma_buf_deinit(void)
977{
978 dma_buf_uninit_debugfs();
979}
980__exitcall(dma_buf_deinit);