source: src/linux/universal/linux-4.9/drivers/dma-buf/dma-buf.c @ 31884

Last change on this file since 31884 was 31884, checked in by brainslayer, 6 weeks ago

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File size: 23.9 KB
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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#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#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}
980module_exit(dma_buf_deinit);
981MODULE_LICENSE("GPL");
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