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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/anon_inodes.h>
29#include <linux/export.h>
30#include <linux/debugfs.h>
31#include <linux/seq_file.h>
32
33static inline int is_dma_buf_file(struct file *);
34
35struct dma_buf_list {
36 struct list_head head;
37 struct mutex lock;
38};
39
40static struct dma_buf_list db_list;
41
42static int dma_buf_release(struct inode *inode, struct file *file)
43{
44 struct dma_buf *dmabuf;
45
46 if (!is_dma_buf_file(file))
47 return -EINVAL;
48
49 dmabuf = file->private_data;
50
51 BUG_ON(dmabuf->vmapping_counter);
52
53 dmabuf->ops->release(dmabuf);
54
55 mutex_lock(&db_list.lock);
56 list_del(&dmabuf->list_node);
57 mutex_unlock(&db_list.lock);
58
59 kfree(dmabuf);
60 return 0;
61}
62
63static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
64{
65 struct dma_buf *dmabuf;
66
67 if (!is_dma_buf_file(file))
68 return -EINVAL;
69
70 dmabuf = file->private_data;
71
72 /* check for overflowing the buffer's size */
73 if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
74 dmabuf->size >> PAGE_SHIFT)
75 return -EINVAL;
76
77 return dmabuf->ops->mmap(dmabuf, vma);
78}
79
80static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
81{
82 struct dma_buf *dmabuf;
83 loff_t base;
84
85 if (!is_dma_buf_file(file))
86 return -EBADF;
87
88 dmabuf = file->private_data;
89
90 /* only support discovering the end of the buffer,
91 but also allow SEEK_SET to maintain the idiomatic
92 SEEK_END(0), SEEK_CUR(0) pattern */
93 if (whence == SEEK_END)
94 base = dmabuf->size;
95 else if (whence == SEEK_SET)
96 base = 0;
97 else
98 return -EINVAL;
99
100 if (offset != 0)
101 return -EINVAL;
102
103 return base + offset;
104}
105
106static const struct file_operations dma_buf_fops = {
107 .release = dma_buf_release,
108 .mmap = dma_buf_mmap_internal,
109 .llseek = dma_buf_llseek,
110};
111
112/*
113 * is_dma_buf_file - Check if struct file* is associated with dma_buf
114 */
115static inline int is_dma_buf_file(struct file *file)
116{
117 return file->f_op == &dma_buf_fops;
118}
119
120/**
121 * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
122 * with this buffer, so it can be exported.
123 * Also connect the allocator specific data and ops to the buffer.
124 * Additionally, provide a name string for exporter; useful in debugging.
125 *
126 * @priv: [in] Attach private data of allocator to this buffer
127 * @ops: [in] Attach allocator-defined dma buf ops to the new buffer.
128 * @size: [in] Size of the buffer
129 * @flags: [in] mode flags for the file.
130 * @exp_name: [in] name of the exporting module - useful for debugging.
131 *
132 * Returns, on success, a newly created dma_buf object, which wraps the
133 * supplied private data and operations for dma_buf_ops. On either missing
134 * ops, or error in allocating struct dma_buf, will return negative error.
135 *
136 */
137struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
138 size_t size, int flags, const char *exp_name)
139{
140 struct dma_buf *dmabuf;
141 struct file *file;
142
143 if (WARN_ON(!priv || !ops
144 || !ops->map_dma_buf
145 || !ops->unmap_dma_buf
146 || !ops->release
147 || !ops->kmap_atomic
148 || !ops->kmap
149 || !ops->mmap)) {
150 return ERR_PTR(-EINVAL);
151 }
152
153 dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
154 if (dmabuf == NULL)
155 return ERR_PTR(-ENOMEM);
156
157 dmabuf->priv = priv;
158 dmabuf->ops = ops;
159 dmabuf->size = size;
160 dmabuf->exp_name = exp_name;
161
162 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
163 if (IS_ERR(file)) {
164 kfree(dmabuf);
165 return ERR_CAST(file);
166 }
167
168 file->f_mode |= FMODE_LSEEK;
169 dmabuf->file = file;
170
171 mutex_init(&dmabuf->lock);
172 INIT_LIST_HEAD(&dmabuf->attachments);
173
174 mutex_lock(&db_list.lock);
175 list_add(&dmabuf->list_node, &db_list.head);
176 mutex_unlock(&db_list.lock);
177
178 return dmabuf;
179}
180EXPORT_SYMBOL_GPL(dma_buf_export_named);
181
182
183/**
184 * dma_buf_fd - returns a file descriptor for the given dma_buf
185 * @dmabuf: [in] pointer to dma_buf for which fd is required.
186 * @flags: [in] flags to give to fd
187 *
188 * On success, returns an associated 'fd'. Else, returns error.
189 */
190int dma_buf_fd(struct dma_buf *dmabuf, int flags)
191{
192 int fd;
193
194 if (!dmabuf || !dmabuf->file)
195 return -EINVAL;
196
197 fd = get_unused_fd_flags(flags);
198 if (fd < 0)
199 return fd;
200
201 fd_install(fd, dmabuf->file);
202
203 return fd;
204}
205EXPORT_SYMBOL_GPL(dma_buf_fd);
206
207/**
208 * dma_buf_get - returns the dma_buf structure related to an fd
209 * @fd: [in] fd associated with the dma_buf to be returned
210 *
211 * On success, returns the dma_buf structure associated with an fd; uses
212 * file's refcounting done by fget to increase refcount. returns ERR_PTR
213 * otherwise.
214 */
215struct dma_buf *dma_buf_get(int fd)
216{
217 struct file *file;
218
219 file = fget(fd);
220
221 if (!file)
222 return ERR_PTR(-EBADF);
223
224 if (!is_dma_buf_file(file)) {
225 fput(file);
226 return ERR_PTR(-EINVAL);
227 }
228
229 return file->private_data;
230}
231EXPORT_SYMBOL_GPL(dma_buf_get);
232
233/**
234 * dma_buf_put - decreases refcount of the buffer
235 * @dmabuf: [in] buffer to reduce refcount of
236 *
237 * Uses file's refcounting done implicitly by fput()
238 */
239void dma_buf_put(struct dma_buf *dmabuf)
240{
241 if (WARN_ON(!dmabuf || !dmabuf->file))
242 return;
243
244 fput(dmabuf->file);
245}
246EXPORT_SYMBOL_GPL(dma_buf_put);
247
248/**
249 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
250 * calls attach() of dma_buf_ops to allow device-specific attach functionality
251 * @dmabuf: [in] buffer to attach device to.
252 * @dev: [in] device to be attached.
253 *
254 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
255 * error.
256 */
257struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
258 struct device *dev)
259{
260 struct dma_buf_attachment *attach;
261 int ret;
262
263 if (WARN_ON(!dmabuf || !dev))
264 return ERR_PTR(-EINVAL);
265
266 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
267 if (attach == NULL)
268 return ERR_PTR(-ENOMEM);
269
270 attach->dev = dev;
271 attach->dmabuf = dmabuf;
272
273 mutex_lock(&dmabuf->lock);
274
275 if (dmabuf->ops->attach) {
276 ret = dmabuf->ops->attach(dmabuf, dev, attach);
277 if (ret)
278 goto err_attach;
279 }
280 list_add(&attach->node, &dmabuf->attachments);
281
282 mutex_unlock(&dmabuf->lock);
283 return attach;
284
285err_attach:
286 kfree(attach);
287 mutex_unlock(&dmabuf->lock);
288 return ERR_PTR(ret);
289}
290EXPORT_SYMBOL_GPL(dma_buf_attach);
291
292/**
293 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
294 * optionally calls detach() of dma_buf_ops for device-specific detach
295 * @dmabuf: [in] buffer to detach from.
296 * @attach: [in] attachment to be detached; is free'd after this call.
297 *
298 */
299void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
300{
301 if (WARN_ON(!dmabuf || !attach))
302 return;
303
304 mutex_lock(&dmabuf->lock);
305 list_del(&attach->node);
306 if (dmabuf->ops->detach)
307 dmabuf->ops->detach(dmabuf, attach);
308
309 mutex_unlock(&dmabuf->lock);
310 kfree(attach);
311}
312EXPORT_SYMBOL_GPL(dma_buf_detach);
313
314/**
315 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
316 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
317 * dma_buf_ops.
318 * @attach: [in] attachment whose scatterlist is to be returned
319 * @direction: [in] direction of DMA transfer
320 *
321 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
322 * on error.
323 */
324struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
325 enum dma_data_direction direction)
326{
327 struct sg_table *sg_table = ERR_PTR(-EINVAL);
328
329 might_sleep();
330
331 if (WARN_ON(!attach || !attach->dmabuf))
332 return ERR_PTR(-EINVAL);
333
334 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
335 if (!sg_table)
336 sg_table = ERR_PTR(-ENOMEM);
337
338 return sg_table;
339}
340EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
341
342/**
343 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
344 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
345 * dma_buf_ops.
346 * @attach: [in] attachment to unmap buffer from
347 * @sg_table: [in] scatterlist info of the buffer to unmap
348 * @direction: [in] direction of DMA transfer
349 *
350 */
351void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
352 struct sg_table *sg_table,
353 enum dma_data_direction direction)
354{
355 might_sleep();
356
357 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
358 return;
359
360 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
361 direction);
362}
363EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
364
365
366/**
367 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
368 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
369 * preparations. Coherency is only guaranteed in the specified range for the
370 * specified access direction.
371 * @dmabuf: [in] buffer to prepare cpu access for.
372 * @start: [in] start of range for cpu access.
373 * @len: [in] length of range for cpu access.
374 * @direction: [in] length of range for cpu access.
375 *
376 * Can return negative error values, returns 0 on success.
377 */
378int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
379 enum dma_data_direction direction)
380{
381 int ret = 0;
382
383 if (WARN_ON(!dmabuf))
384 return -EINVAL;
385
386 if (dmabuf->ops->begin_cpu_access)
387 ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
388
389 return ret;
390}
391EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
392
393/**
394 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
395 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
396 * actions. Coherency is only guaranteed in the specified range for the
397 * specified access direction.
398 * @dmabuf: [in] buffer to complete cpu access for.
399 * @start: [in] start of range for cpu access.
400 * @len: [in] length of range for cpu access.
401 * @direction: [in] length of range for cpu access.
402 *
403 * This call must always succeed.
404 */
405void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
406 enum dma_data_direction direction)
407{
408 WARN_ON(!dmabuf);
409
410 if (dmabuf->ops->end_cpu_access)
411 dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
412}
413EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
414
415/**
416 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
417 * space. The same restrictions as for kmap_atomic and friends apply.
418 * @dmabuf: [in] buffer to map page from.
419 * @page_num: [in] page in PAGE_SIZE units to map.
420 *
421 * This call must always succeed, any necessary preparations that might fail
422 * need to be done in begin_cpu_access.
423 */
424void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
425{
426 WARN_ON(!dmabuf);
427
428 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
429}
430EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
431
432/**
433 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
434 * @dmabuf: [in] buffer to unmap page from.
435 * @page_num: [in] page in PAGE_SIZE units to unmap.
436 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
437 *
438 * This call must always succeed.
439 */
440void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
441 void *vaddr)
442{
443 WARN_ON(!dmabuf);
444
445 if (dmabuf->ops->kunmap_atomic)
446 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
447}
448EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
449
450/**
451 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
452 * same restrictions as for kmap and friends apply.
453 * @dmabuf: [in] buffer to map page from.
454 * @page_num: [in] page in PAGE_SIZE units to map.
455 *
456 * This call must always succeed, any necessary preparations that might fail
457 * need to be done in begin_cpu_access.
458 */
459void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
460{
461 WARN_ON(!dmabuf);
462
463 return dmabuf->ops->kmap(dmabuf, page_num);
464}
465EXPORT_SYMBOL_GPL(dma_buf_kmap);
466
467/**
468 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
469 * @dmabuf: [in] buffer to unmap page from.
470 * @page_num: [in] page in PAGE_SIZE units to unmap.
471 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
472 *
473 * This call must always succeed.
474 */
475void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
476 void *vaddr)
477{
478 WARN_ON(!dmabuf);
479
480 if (dmabuf->ops->kunmap)
481 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
482}
483EXPORT_SYMBOL_GPL(dma_buf_kunmap);
484
485
486/**
487 * dma_buf_mmap - Setup up a userspace mmap with the given vma
488 * @dmabuf: [in] buffer that should back the vma
489 * @vma: [in] vma for the mmap
490 * @pgoff: [in] offset in pages where this mmap should start within the
491 * dma-buf buffer.
492 *
493 * This function adjusts the passed in vma so that it points at the file of the
494 * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
495 * checking on the size of the vma. Then it calls the exporters mmap function to
496 * set up the mapping.
497 *
498 * Can return negative error values, returns 0 on success.
499 */
500int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
501 unsigned long pgoff)
502{
503 struct file *oldfile;
504 int ret;
505
506 if (WARN_ON(!dmabuf || !vma))
507 return -EINVAL;
508
509 /* check for offset overflow */
510 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
511 return -EOVERFLOW;
512
513 /* check for overflowing the buffer's size */
514 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
515 dmabuf->size >> PAGE_SHIFT)
516 return -EINVAL;
517
518 /* readjust the vma */
519 get_file(dmabuf->file);
520 oldfile = vma->vm_file;
521 vma->vm_file = dmabuf->file;
522 vma->vm_pgoff = pgoff;
523
524 ret = dmabuf->ops->mmap(dmabuf, vma);
525 if (ret) {
526 /* restore old parameters on failure */
527 vma->vm_file = oldfile;
528 fput(dmabuf->file);
529 } else {
530 if (oldfile)
531 fput(oldfile);
532 }
533 return ret;
534
535}
536EXPORT_SYMBOL_GPL(dma_buf_mmap);
537
538/**
539 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
540 * address space. Same restrictions as for vmap and friends apply.
541 * @dmabuf: [in] buffer to vmap
542 *
543 * This call may fail due to lack of virtual mapping address space.
544 * These calls are optional in drivers. The intended use for them
545 * is for mapping objects linear in kernel space for high use objects.
546 * Please attempt to use kmap/kunmap before thinking about these interfaces.
547 *
548 * Returns NULL on error.
549 */
550void *dma_buf_vmap(struct dma_buf *dmabuf)
551{
552 void *ptr;
553
554 if (WARN_ON(!dmabuf))
555 return NULL;
556
557 if (!dmabuf->ops->vmap)
558 return NULL;
559
560 mutex_lock(&dmabuf->lock);
561 if (dmabuf->vmapping_counter) {
562 dmabuf->vmapping_counter++;
563 BUG_ON(!dmabuf->vmap_ptr);
564 ptr = dmabuf->vmap_ptr;
565 goto out_unlock;
566 }
567
568 BUG_ON(dmabuf->vmap_ptr);
569
570 ptr = dmabuf->ops->vmap(dmabuf);
571 if (WARN_ON_ONCE(IS_ERR(ptr)))
572 ptr = NULL;
573 if (!ptr)
574 goto out_unlock;
575
576 dmabuf->vmap_ptr = ptr;
577 dmabuf->vmapping_counter = 1;
578
579out_unlock:
580 mutex_unlock(&dmabuf->lock);
581 return ptr;
582}
583EXPORT_SYMBOL_GPL(dma_buf_vmap);
584
585/**
586 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
587 * @dmabuf: [in] buffer to vunmap
588 * @vaddr: [in] vmap to vunmap
589 */
590void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
591{
592 if (WARN_ON(!dmabuf))
593 return;
594
595 BUG_ON(!dmabuf->vmap_ptr);
596 BUG_ON(dmabuf->vmapping_counter == 0);
597 BUG_ON(dmabuf->vmap_ptr != vaddr);
598
599 mutex_lock(&dmabuf->lock);
600 if (--dmabuf->vmapping_counter == 0) {
601 if (dmabuf->ops->vunmap)
602 dmabuf->ops->vunmap(dmabuf, vaddr);
603 dmabuf->vmap_ptr = NULL;
604 }
605 mutex_unlock(&dmabuf->lock);
606}
607EXPORT_SYMBOL_GPL(dma_buf_vunmap);
608
609#ifdef CONFIG_DEBUG_FS
610static int dma_buf_describe(struct seq_file *s)
611{
612 int ret;
613 struct dma_buf *buf_obj;
614 struct dma_buf_attachment *attach_obj;
615 int count = 0, attach_count;
616 size_t size = 0;
617
618 ret = mutex_lock_interruptible(&db_list.lock);
619
620 if (ret)
621 return ret;
622
623 seq_puts(s, "\nDma-buf Objects:\n");
624 seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
625
626 list_for_each_entry(buf_obj, &db_list.head, list_node) {
627 ret = mutex_lock_interruptible(&buf_obj->lock);
628
629 if (ret) {
630 seq_puts(s,
631 "\tERROR locking buffer object: skipping\n");
632 continue;
633 }
634
635 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
636 buf_obj->size,
637 buf_obj->file->f_flags, buf_obj->file->f_mode,
638 (long)(buf_obj->file->f_count.counter),
639 buf_obj->exp_name);
640
641 seq_puts(s, "\tAttached Devices:\n");
642 attach_count = 0;
643
644 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
645 seq_puts(s, "\t");
646
647 seq_printf(s, "%s\n", dev_name(attach_obj->dev));
648 attach_count++;
649 }
650
651 seq_printf(s, "Total %d devices attached\n\n",
652 attach_count);
653
654 count++;
655 size += buf_obj->size;
656 mutex_unlock(&buf_obj->lock);
657 }
658
659 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
660
661 mutex_unlock(&db_list.lock);
662 return 0;
663}
664
665static int dma_buf_show(struct seq_file *s, void *unused)
666{
667 void (*func)(struct seq_file *) = s->private;
668 func(s);
669 return 0;
670}
671
672static int dma_buf_debug_open(struct inode *inode, struct file *file)
673{
674 return single_open(file, dma_buf_show, inode->i_private);
675}
676
677static const struct file_operations dma_buf_debug_fops = {
678 .open = dma_buf_debug_open,
679 .read = seq_read,
680 .llseek = seq_lseek,
681 .release = single_release,
682};
683
684static struct dentry *dma_buf_debugfs_dir;
685
686static int dma_buf_init_debugfs(void)
687{
688 int err = 0;
689 dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
690 if (IS_ERR(dma_buf_debugfs_dir)) {
691 err = PTR_ERR(dma_buf_debugfs_dir);
692 dma_buf_debugfs_dir = NULL;
693 return err;
694 }
695
696 err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
697
698 if (err)
699 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
700
701 return err;
702}
703
704static void dma_buf_uninit_debugfs(void)
705{
706 if (dma_buf_debugfs_dir)
707 debugfs_remove_recursive(dma_buf_debugfs_dir);
708}
709
710int dma_buf_debugfs_create_file(const char *name,
711 int (*write)(struct seq_file *))
712{
713 struct dentry *d;
714
715 d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
716 write, &dma_buf_debug_fops);
717
718 return PTR_ERR_OR_ZERO(d);
719}
720#else
721static inline int dma_buf_init_debugfs(void)
722{
723 return 0;
724}
725static inline void dma_buf_uninit_debugfs(void)
726{
727}
728#endif
729
730static int __init dma_buf_init(void)
731{
732 mutex_init(&db_list.lock);
733 INIT_LIST_HEAD(&db_list.head);
734 dma_buf_init_debugfs();
735 return 0;
736}
737subsys_initcall(dma_buf_init);
738
739static void __exit dma_buf_deinit(void)
740{
741 dma_buf_uninit_debugfs();
742}
743__exitcall(dma_buf_deinit);