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