source: src/linux/universal/linux-4.9/drivers/dma-buf/dma-buf.c @ 31574

Last change on this file since 31574 was 31574, checked in by brainslayer, 5 months ago

kernel 4.9 update

File size: 23.8 KB
Line 
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#include <linux/mm.h>
37#include <uapi/linux/dma-buf.h>
38#include <linux/module.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 fence *fence, struct 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 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 (!fence_get_rcu(fence_excl)) {
191                                /* force a recheck */
192                                events &= ~pevents;
193                                dma_buf_poll_cb(NULL, &dcb->cb);
194                        } else if (!fence_add_callback(fence_excl, &dcb->cb,
195                                                       dma_buf_poll_cb)) {
196                                events &= ~pevents;
197                                fence_put(fence_excl);
198                        } else {
199                                /*
200                                 * No callback queued, wake up any additional
201                                 * waiters.
202                                 */
203                                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 fence *fence = rcu_dereference(fobj->shared[i]);
226
227                        if (!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 (!fence_add_callback(fence, &dcb->cb,
239                                                dma_buf_poll_cb)) {
240                                fence_put(fence);
241                                events &= ~POLLOUT;
242                                break;
243                        }
244                        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};
307
308/*
309 * is_dma_buf_file - Check if struct file* is associated with dma_buf
310 */
311static inline int is_dma_buf_file(struct file *file)
312{
313        return file->f_op == &dma_buf_fops;
314}
315
316/**
317 * dma_buf_export - Creates a new dma_buf, and associates an anon file
318 * with this buffer, so it can be exported.
319 * Also connect the allocator specific data and ops to the buffer.
320 * Additionally, provide a name string for exporter; useful in debugging.
321 *
322 * @exp_info:   [in]    holds all the export related information provided
323 *                      by the exporter. see struct dma_buf_export_info
324 *                      for further details.
325 *
326 * Returns, on success, a newly created dma_buf object, which wraps the
327 * supplied private data and operations for dma_buf_ops. On either missing
328 * ops, or error in allocating struct dma_buf, will return negative error.
329 *
330 */
331struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
332{
333        struct dma_buf *dmabuf;
334        struct reservation_object *resv = exp_info->resv;
335        struct file *file;
336        size_t alloc_size = sizeof(struct dma_buf);
337        int ret;
338
339        if (!exp_info->resv)
340                alloc_size += sizeof(struct reservation_object);
341        else
342                /* prevent &dma_buf[1] == dma_buf->resv */
343                alloc_size += 1;
344
345        if (WARN_ON(!exp_info->priv
346                          || !exp_info->ops
347                          || !exp_info->ops->map_dma_buf
348                          || !exp_info->ops->unmap_dma_buf
349                          || !exp_info->ops->release
350                          || !exp_info->ops->kmap_atomic
351                          || !exp_info->ops->kmap
352                          || !exp_info->ops->mmap)) {
353                return ERR_PTR(-EINVAL);
354        }
355
356        if (!try_module_get(exp_info->owner))
357                return ERR_PTR(-ENOENT);
358
359        dmabuf = kzalloc(alloc_size, GFP_KERNEL);
360        if (!dmabuf) {
361                ret = -ENOMEM;
362                goto err_module;
363        }
364
365        dmabuf->priv = exp_info->priv;
366        dmabuf->ops = exp_info->ops;
367        dmabuf->size = exp_info->size;
368        dmabuf->exp_name = exp_info->exp_name;
369        dmabuf->owner = exp_info->owner;
370        init_waitqueue_head(&dmabuf->poll);
371        dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
372        dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
373
374        if (!resv) {
375                resv = (struct reservation_object *)&dmabuf[1];
376                reservation_object_init(resv);
377        }
378        dmabuf->resv = resv;
379
380        file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
381                                        exp_info->flags);
382        if (IS_ERR(file)) {
383                ret = PTR_ERR(file);
384                goto err_dmabuf;
385        }
386
387        file->f_mode |= FMODE_LSEEK;
388        dmabuf->file = file;
389
390        mutex_init(&dmabuf->lock);
391        INIT_LIST_HEAD(&dmabuf->attachments);
392
393        mutex_lock(&db_list.lock);
394        list_add(&dmabuf->list_node, &db_list.head);
395        mutex_unlock(&db_list.lock);
396
397        return dmabuf;
398
399err_dmabuf:
400        kfree(dmabuf);
401err_module:
402        module_put(exp_info->owner);
403        return ERR_PTR(ret);
404}
405EXPORT_SYMBOL_GPL(dma_buf_export);
406
407/**
408 * dma_buf_fd - returns a file descriptor for the given dma_buf
409 * @dmabuf:     [in]    pointer to dma_buf for which fd is required.
410 * @flags:      [in]    flags to give to fd
411 *
412 * On success, returns an associated 'fd'. Else, returns error.
413 */
414int dma_buf_fd(struct dma_buf *dmabuf, int flags)
415{
416        int fd;
417
418        if (!dmabuf || !dmabuf->file)
419                return -EINVAL;
420
421        fd = get_unused_fd_flags(flags);
422        if (fd < 0)
423                return fd;
424
425        fd_install(fd, dmabuf->file);
426
427        return fd;
428}
429EXPORT_SYMBOL_GPL(dma_buf_fd);
430
431/**
432 * dma_buf_get - returns the dma_buf structure related to an fd
433 * @fd: [in]    fd associated with the dma_buf to be returned
434 *
435 * On success, returns the dma_buf structure associated with an fd; uses
436 * file's refcounting done by fget to increase refcount. returns ERR_PTR
437 * otherwise.
438 */
439struct dma_buf *dma_buf_get(int fd)
440{
441        struct file *file;
442
443        file = fget(fd);
444
445        if (!file)
446                return ERR_PTR(-EBADF);
447
448        if (!is_dma_buf_file(file)) {
449                fput(file);
450                return ERR_PTR(-EINVAL);
451        }
452
453        return file->private_data;
454}
455EXPORT_SYMBOL_GPL(dma_buf_get);
456
457/**
458 * dma_buf_put - decreases refcount of the buffer
459 * @dmabuf:     [in]    buffer to reduce refcount of
460 *
461 * Uses file's refcounting done implicitly by fput()
462 */
463void dma_buf_put(struct dma_buf *dmabuf)
464{
465        if (WARN_ON(!dmabuf || !dmabuf->file))
466                return;
467
468        fput(dmabuf->file);
469}
470EXPORT_SYMBOL_GPL(dma_buf_put);
471
472/**
473 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
474 * calls attach() of dma_buf_ops to allow device-specific attach functionality
475 * @dmabuf:     [in]    buffer to attach device to.
476 * @dev:        [in]    device to be attached.
477 *
478 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
479 * error.
480 */
481struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
482                                          struct device *dev)
483{
484        struct dma_buf_attachment *attach;
485        int ret;
486
487        if (WARN_ON(!dmabuf || !dev))
488                return ERR_PTR(-EINVAL);
489
490        attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
491        if (attach == NULL)
492                return ERR_PTR(-ENOMEM);
493
494        attach->dev = dev;
495        attach->dmabuf = dmabuf;
496
497        mutex_lock(&dmabuf->lock);
498
499        if (dmabuf->ops->attach) {
500                ret = dmabuf->ops->attach(dmabuf, dev, attach);
501                if (ret)
502                        goto err_attach;
503        }
504        list_add(&attach->node, &dmabuf->attachments);
505
506        mutex_unlock(&dmabuf->lock);
507        return attach;
508
509err_attach:
510        kfree(attach);
511        mutex_unlock(&dmabuf->lock);
512        return ERR_PTR(ret);
513}
514EXPORT_SYMBOL_GPL(dma_buf_attach);
515
516/**
517 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
518 * optionally calls detach() of dma_buf_ops for device-specific detach
519 * @dmabuf:     [in]    buffer to detach from.
520 * @attach:     [in]    attachment to be detached; is free'd after this call.
521 *
522 */
523void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
524{
525        if (WARN_ON(!dmabuf || !attach))
526                return;
527
528        mutex_lock(&dmabuf->lock);
529        list_del(&attach->node);
530        if (dmabuf->ops->detach)
531                dmabuf->ops->detach(dmabuf, attach);
532
533        mutex_unlock(&dmabuf->lock);
534        kfree(attach);
535}
536EXPORT_SYMBOL_GPL(dma_buf_detach);
537
538/**
539 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
540 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
541 * dma_buf_ops.
542 * @attach:     [in]    attachment whose scatterlist is to be returned
543 * @direction:  [in]    direction of DMA transfer
544 *
545 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
546 * on error.
547 */
548struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
549                                        enum dma_data_direction direction)
550{
551        struct sg_table *sg_table = ERR_PTR(-EINVAL);
552
553        might_sleep();
554
555        if (WARN_ON(!attach || !attach->dmabuf))
556                return ERR_PTR(-EINVAL);
557
558        sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
559        if (!sg_table)
560                sg_table = ERR_PTR(-ENOMEM);
561
562        return sg_table;
563}
564EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
565
566/**
567 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
568 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
569 * dma_buf_ops.
570 * @attach:     [in]    attachment to unmap buffer from
571 * @sg_table:   [in]    scatterlist info of the buffer to unmap
572 * @direction:  [in]    direction of DMA transfer
573 *
574 */
575void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
576                                struct sg_table *sg_table,
577                                enum dma_data_direction direction)
578{
579        might_sleep();
580
581        if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
582                return;
583
584        attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
585                                                direction);
586}
587EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
588
589static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
590                                      enum dma_data_direction direction)
591{
592        bool write = (direction == DMA_BIDIRECTIONAL ||
593                      direction == DMA_TO_DEVICE);
594        struct reservation_object *resv = dmabuf->resv;
595        long ret;
596
597        /* Wait on any implicit rendering fences */
598        ret = reservation_object_wait_timeout_rcu(resv, write, true,
599                                                  MAX_SCHEDULE_TIMEOUT);
600        if (ret < 0)
601                return ret;
602
603        return 0;
604}
605
606/**
607 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
608 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
609 * preparations. Coherency is only guaranteed in the specified range for the
610 * specified access direction.
611 * @dmabuf:     [in]    buffer to prepare cpu access for.
612 * @direction:  [in]    length of range for cpu access.
613 *
614 * Can return negative error values, returns 0 on success.
615 */
616int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
617                             enum dma_data_direction direction)
618{
619        int ret = 0;
620
621        if (WARN_ON(!dmabuf))
622                return -EINVAL;
623
624        if (dmabuf->ops->begin_cpu_access)
625                ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
626
627        /* Ensure that all fences are waited upon - but we first allow
628         * the native handler the chance to do so more efficiently if it
629         * chooses. A double invocation here will be reasonably cheap no-op.
630         */
631        if (ret == 0)
632                ret = __dma_buf_begin_cpu_access(dmabuf, direction);
633
634        return ret;
635}
636EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
637
638/**
639 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
640 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
641 * actions. Coherency is only guaranteed in the specified range for the
642 * specified access direction.
643 * @dmabuf:     [in]    buffer to complete cpu access for.
644 * @direction:  [in]    length of range for cpu access.
645 *
646 * Can return negative error values, returns 0 on success.
647 */
648int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
649                           enum dma_data_direction direction)
650{
651        int ret = 0;
652
653        WARN_ON(!dmabuf);
654
655        if (dmabuf->ops->end_cpu_access)
656                ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
657
658        return ret;
659}
660EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
661
662/**
663 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
664 * space. The same restrictions as for kmap_atomic and friends apply.
665 * @dmabuf:     [in]    buffer to map page from.
666 * @page_num:   [in]    page in PAGE_SIZE units to map.
667 *
668 * This call must always succeed, any necessary preparations that might fail
669 * need to be done in begin_cpu_access.
670 */
671void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
672{
673        WARN_ON(!dmabuf);
674
675        return dmabuf->ops->kmap_atomic(dmabuf, page_num);
676}
677EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
678
679/**
680 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
681 * @dmabuf:     [in]    buffer to unmap page from.
682 * @page_num:   [in]    page in PAGE_SIZE units to unmap.
683 * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap_atomic.
684 *
685 * This call must always succeed.
686 */
687void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
688                           void *vaddr)
689{
690        WARN_ON(!dmabuf);
691
692        if (dmabuf->ops->kunmap_atomic)
693                dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
694}
695EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
696
697/**
698 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
699 * same restrictions as for kmap and friends apply.
700 * @dmabuf:     [in]    buffer to map page from.
701 * @page_num:   [in]    page in PAGE_SIZE units to map.
702 *
703 * This call must always succeed, any necessary preparations that might fail
704 * need to be done in begin_cpu_access.
705 */
706void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
707{
708        WARN_ON(!dmabuf);
709
710        return dmabuf->ops->kmap(dmabuf, page_num);
711}
712EXPORT_SYMBOL_GPL(dma_buf_kmap);
713
714/**
715 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
716 * @dmabuf:     [in]    buffer to unmap page from.
717 * @page_num:   [in]    page in PAGE_SIZE units to unmap.
718 * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap.
719 *
720 * This call must always succeed.
721 */
722void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
723                    void *vaddr)
724{
725        WARN_ON(!dmabuf);
726
727        if (dmabuf->ops->kunmap)
728                dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
729}
730EXPORT_SYMBOL_GPL(dma_buf_kunmap);
731
732
733/**
734 * dma_buf_mmap - Setup up a userspace mmap with the given vma
735 * @dmabuf:     [in]    buffer that should back the vma
736 * @vma:        [in]    vma for the mmap
737 * @pgoff:      [in]    offset in pages where this mmap should start within the
738 *                      dma-buf buffer.
739 *
740 * This function adjusts the passed in vma so that it points at the file of the
741 * dma_buf operation. It also adjusts the starting pgoff and does bounds
742 * checking on the size of the vma. Then it calls the exporters mmap function to
743 * set up the mapping.
744 *
745 * Can return negative error values, returns 0 on success.
746 */
747int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
748                 unsigned long pgoff)
749{
750        struct file *oldfile;
751        int ret;
752
753        if (WARN_ON(!dmabuf || !vma))
754                return -EINVAL;
755
756        /* check for offset overflow */
757        if (pgoff + vma_pages(vma) < pgoff)
758                return -EOVERFLOW;
759
760        /* check for overflowing the buffer's size */
761        if (pgoff + vma_pages(vma) >
762            dmabuf->size >> PAGE_SHIFT)
763                return -EINVAL;
764
765        /* readjust the vma */
766        get_file(dmabuf->file);
767        oldfile = vma->vm_file;
768        vma->vm_file = dmabuf->file;
769        vma->vm_pgoff = pgoff;
770
771        ret = dmabuf->ops->mmap(dmabuf, vma);
772        if (ret) {
773                /* restore old parameters on failure */
774                vma->vm_file = oldfile;
775                fput(dmabuf->file);
776        } else {
777                if (oldfile)
778                        fput(oldfile);
779        }
780        return ret;
781
782}
783EXPORT_SYMBOL_GPL(dma_buf_mmap);
784
785/**
786 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
787 * address space. Same restrictions as for vmap and friends apply.
788 * @dmabuf:     [in]    buffer to vmap
789 *
790 * This call may fail due to lack of virtual mapping address space.
791 * These calls are optional in drivers. The intended use for them
792 * is for mapping objects linear in kernel space for high use objects.
793 * Please attempt to use kmap/kunmap before thinking about these interfaces.
794 *
795 * Returns NULL on error.
796 */
797void *dma_buf_vmap(struct dma_buf *dmabuf)
798{
799        void *ptr;
800
801        if (WARN_ON(!dmabuf))
802                return NULL;
803
804        if (!dmabuf->ops->vmap)
805                return NULL;
806
807        mutex_lock(&dmabuf->lock);
808        if (dmabuf->vmapping_counter) {
809                dmabuf->vmapping_counter++;
810                BUG_ON(!dmabuf->vmap_ptr);
811                ptr = dmabuf->vmap_ptr;
812                goto out_unlock;
813        }
814
815        BUG_ON(dmabuf->vmap_ptr);
816
817        ptr = dmabuf->ops->vmap(dmabuf);
818        if (WARN_ON_ONCE(IS_ERR(ptr)))
819                ptr = NULL;
820        if (!ptr)
821                goto out_unlock;
822
823        dmabuf->vmap_ptr = ptr;
824        dmabuf->vmapping_counter = 1;
825
826out_unlock:
827        mutex_unlock(&dmabuf->lock);
828        return ptr;
829}
830EXPORT_SYMBOL_GPL(dma_buf_vmap);
831
832/**
833 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
834 * @dmabuf:     [in]    buffer to vunmap
835 * @vaddr:      [in]    vmap to vunmap
836 */
837void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
838{
839        if (WARN_ON(!dmabuf))
840                return;
841
842        BUG_ON(!dmabuf->vmap_ptr);
843        BUG_ON(dmabuf->vmapping_counter == 0);
844        BUG_ON(dmabuf->vmap_ptr != vaddr);
845
846        mutex_lock(&dmabuf->lock);
847        if (--dmabuf->vmapping_counter == 0) {
848                if (dmabuf->ops->vunmap)
849                        dmabuf->ops->vunmap(dmabuf, vaddr);
850                dmabuf->vmap_ptr = NULL;
851        }
852        mutex_unlock(&dmabuf->lock);
853}
854EXPORT_SYMBOL_GPL(dma_buf_vunmap);
855
856#ifdef CONFIG_DEBUG_FS
857static int dma_buf_debug_show(struct seq_file *s, void *unused)
858{
859        int ret;
860        struct dma_buf *buf_obj;
861        struct dma_buf_attachment *attach_obj;
862        int count = 0, attach_count;
863        size_t size = 0;
864
865        ret = mutex_lock_interruptible(&db_list.lock);
866
867        if (ret)
868                return ret;
869
870        seq_puts(s, "\nDma-buf Objects:\n");
871        seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
872
873        list_for_each_entry(buf_obj, &db_list.head, list_node) {
874                ret = mutex_lock_interruptible(&buf_obj->lock);
875
876                if (ret) {
877                        seq_puts(s,
878                                 "\tERROR locking buffer object: skipping\n");
879                        continue;
880                }
881
882                seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
883                                buf_obj->size,
884                                buf_obj->file->f_flags, buf_obj->file->f_mode,
885                                file_count(buf_obj->file),
886                                buf_obj->exp_name);
887
888                seq_puts(s, "\tAttached Devices:\n");
889                attach_count = 0;
890
891                list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
892                        seq_puts(s, "\t");
893
894                        seq_printf(s, "%s\n", dev_name(attach_obj->dev));
895                        attach_count++;
896                }
897
898                seq_printf(s, "Total %d devices attached\n\n",
899                                attach_count);
900
901                count++;
902                size += buf_obj->size;
903                mutex_unlock(&buf_obj->lock);
904        }
905
906        seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
907
908        mutex_unlock(&db_list.lock);
909        return 0;
910}
911
912static int dma_buf_debug_open(struct inode *inode, struct file *file)
913{
914        return single_open(file, dma_buf_debug_show, NULL);
915}
916
917static const struct file_operations dma_buf_debug_fops = {
918        .open           = dma_buf_debug_open,
919        .read           = seq_read,
920        .llseek         = seq_lseek,
921        .release        = single_release,
922};
923
924static struct dentry *dma_buf_debugfs_dir;
925
926static int dma_buf_init_debugfs(void)
927{
928        struct dentry *d;
929        int err = 0;
930
931        d = debugfs_create_dir("dma_buf", NULL);
932        if (IS_ERR(d))
933                return PTR_ERR(d);
934
935        dma_buf_debugfs_dir = d;
936
937        d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
938                                NULL, &dma_buf_debug_fops);
939        if (IS_ERR(d)) {
940                pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
941                debugfs_remove_recursive(dma_buf_debugfs_dir);
942                dma_buf_debugfs_dir = NULL;
943                err = PTR_ERR(d);
944        }
945
946        return err;
947}
948
949static void dma_buf_uninit_debugfs(void)
950{
951        if (dma_buf_debugfs_dir)
952                debugfs_remove_recursive(dma_buf_debugfs_dir);
953}
954#else
955static inline int dma_buf_init_debugfs(void)
956{
957        return 0;
958}
959static inline void dma_buf_uninit_debugfs(void)
960{
961}
962#endif
963
964static int __init dma_buf_init(void)
965{
966        mutex_init(&db_list.lock);
967        INIT_LIST_HEAD(&db_list.head);
968        dma_buf_init_debugfs();
969        return 0;
970}
971subsys_initcall(dma_buf_init);
972
973static void __exit dma_buf_deinit(void)
974{
975        dma_buf_uninit_debugfs();
976}
977module_exit(dma_buf_deinit);
978MODULE_LICENSE("GPL");
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