2 * Framework for buffer objects that can be shared across devices/subsystems.
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Author: Sumit Semwal <sumit.semwal@ti.com>
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.
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.
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
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/>.
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>
37 #include <uapi/linux/dma-buf.h>
39 static inline int is_dma_buf_file(struct file *);
42 struct list_head head;
46 static struct dma_buf_list db_list;
48 static int dma_buf_release(struct inode *inode, struct file *file)
50 struct dma_buf *dmabuf;
52 if (!is_dma_buf_file(file))
55 dmabuf = file->private_data;
57 BUG_ON(dmabuf->vmapping_counter);
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.
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.
67 BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
69 dmabuf->ops->release(dmabuf);
71 mutex_lock(&db_list.lock);
72 list_del(&dmabuf->list_node);
73 mutex_unlock(&db_list.lock);
75 if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
76 reservation_object_fini(dmabuf->resv);
78 module_put(dmabuf->owner);
83 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
85 struct dma_buf *dmabuf;
87 if (!is_dma_buf_file(file))
90 dmabuf = file->private_data;
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)
97 return dmabuf->ops->mmap(dmabuf, vma);
100 static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
102 struct dma_buf *dmabuf;
105 if (!is_dma_buf_file(file))
108 dmabuf = file->private_data;
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)
115 else if (whence == SEEK_SET)
123 return base + offset;
126 static void dma_buf_poll_cb(struct fence *fence, struct fence_cb *cb)
128 struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
131 spin_lock_irqsave(&dcb->poll->lock, flags);
132 wake_up_locked_poll(dcb->poll, dcb->active);
134 spin_unlock_irqrestore(&dcb->poll->lock, flags);
137 static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
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;
146 dmabuf = file->private_data;
147 if (!dmabuf || !dmabuf->resv)
152 poll_wait(file, &dmabuf->poll, poll);
154 events = poll_requested_events(poll) & (POLLIN | POLLOUT);
159 seq = read_seqcount_begin(&resv->seq);
162 fobj = rcu_dereference(resv->fence);
164 shared_count = fobj->shared_count;
167 fence_excl = rcu_dereference(resv->fence_excl);
168 if (read_seqcount_retry(&resv->seq, seq)) {
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;
177 if (shared_count == 0)
180 spin_lock_irq(&dmabuf->poll.lock);
182 dcb->active |= pevents;
185 dcb->active = pevents;
186 spin_unlock_irq(&dmabuf->poll.lock);
188 if (events & pevents) {
189 if (!fence_get_rcu(fence_excl)) {
190 /* force a recheck */
192 dma_buf_poll_cb(NULL, &dcb->cb);
193 } else if (!fence_add_callback(fence_excl, &dcb->cb,
196 fence_put(fence_excl);
199 * No callback queued, wake up any additional
202 fence_put(fence_excl);
203 dma_buf_poll_cb(NULL, &dcb->cb);
208 if ((events & POLLOUT) && shared_count > 0) {
209 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
212 /* Only queue a new callback if no event has fired yet */
213 spin_lock_irq(&dmabuf->poll.lock);
217 dcb->active = POLLOUT;
218 spin_unlock_irq(&dmabuf->poll.lock);
220 if (!(events & POLLOUT))
223 for (i = 0; i < shared_count; ++i) {
224 struct fence *fence = rcu_dereference(fobj->shared[i]);
226 if (!fence_get_rcu(fence)) {
228 * fence refcount dropped to zero, this means
229 * that fobj has been freed
231 * call dma_buf_poll_cb and force a recheck!
234 dma_buf_poll_cb(NULL, &dcb->cb);
237 if (!fence_add_callback(fence, &dcb->cb,
246 /* No callback queued, wake up any additional waiters. */
247 if (i == shared_count)
248 dma_buf_poll_cb(NULL, &dcb->cb);
256 static long dma_buf_ioctl(struct file *file,
257 unsigned int cmd, unsigned long arg)
259 struct dma_buf *dmabuf;
260 struct dma_buf_sync sync;
261 enum dma_data_direction direction;
263 dmabuf = file->private_data;
266 case DMA_BUF_IOCTL_SYNC:
267 if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
270 if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
273 switch (sync.flags & DMA_BUF_SYNC_RW) {
274 case DMA_BUF_SYNC_READ:
275 direction = DMA_FROM_DEVICE;
277 case DMA_BUF_SYNC_WRITE:
278 direction = DMA_TO_DEVICE;
280 case DMA_BUF_SYNC_RW:
281 direction = DMA_BIDIRECTIONAL;
287 if (sync.flags & DMA_BUF_SYNC_END)
288 dma_buf_end_cpu_access(dmabuf, direction);
290 dma_buf_begin_cpu_access(dmabuf, direction);
298 static const struct file_operations dma_buf_fops = {
299 .release = dma_buf_release,
300 .mmap = dma_buf_mmap_internal,
301 .llseek = dma_buf_llseek,
302 .poll = dma_buf_poll,
303 .unlocked_ioctl = dma_buf_ioctl,
307 * is_dma_buf_file - Check if struct file* is associated with dma_buf
309 static inline int is_dma_buf_file(struct file *file)
311 return file->f_op == &dma_buf_fops;
315 * dma_buf_export - Creates a new dma_buf, and associates an anon file
316 * with this buffer, so it can be exported.
317 * Also connect the allocator specific data and ops to the buffer.
318 * Additionally, provide a name string for exporter; useful in debugging.
320 * @exp_info: [in] holds all the export related information provided
321 * by the exporter. see struct dma_buf_export_info
322 * for further details.
324 * Returns, on success, a newly created dma_buf object, which wraps the
325 * supplied private data and operations for dma_buf_ops. On either missing
326 * ops, or error in allocating struct dma_buf, will return negative error.
329 struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
331 struct dma_buf *dmabuf;
332 struct reservation_object *resv = exp_info->resv;
334 size_t alloc_size = sizeof(struct dma_buf);
337 alloc_size += sizeof(struct reservation_object);
339 /* prevent &dma_buf[1] == dma_buf->resv */
342 if (WARN_ON(!exp_info->priv
344 || !exp_info->ops->map_dma_buf
345 || !exp_info->ops->unmap_dma_buf
346 || !exp_info->ops->release
347 || !exp_info->ops->kmap_atomic
348 || !exp_info->ops->kmap
349 || !exp_info->ops->mmap)) {
350 return ERR_PTR(-EINVAL);
353 if (!try_module_get(exp_info->owner))
354 return ERR_PTR(-ENOENT);
356 dmabuf = kzalloc(alloc_size, GFP_KERNEL);
358 module_put(exp_info->owner);
359 return ERR_PTR(-ENOMEM);
362 dmabuf->priv = exp_info->priv;
363 dmabuf->ops = exp_info->ops;
364 dmabuf->size = exp_info->size;
365 dmabuf->exp_name = exp_info->exp_name;
366 dmabuf->owner = exp_info->owner;
367 init_waitqueue_head(&dmabuf->poll);
368 dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
369 dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
372 resv = (struct reservation_object *)&dmabuf[1];
373 reservation_object_init(resv);
377 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
381 return ERR_CAST(file);
384 file->f_mode |= FMODE_LSEEK;
387 mutex_init(&dmabuf->lock);
388 INIT_LIST_HEAD(&dmabuf->attachments);
390 mutex_lock(&db_list.lock);
391 list_add(&dmabuf->list_node, &db_list.head);
392 mutex_unlock(&db_list.lock);
396 EXPORT_SYMBOL_GPL(dma_buf_export);
399 * dma_buf_fd - returns a file descriptor for the given dma_buf
400 * @dmabuf: [in] pointer to dma_buf for which fd is required.
401 * @flags: [in] flags to give to fd
403 * On success, returns an associated 'fd'. Else, returns error.
405 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
409 if (!dmabuf || !dmabuf->file)
412 fd = get_unused_fd_flags(flags);
416 fd_install(fd, dmabuf->file);
420 EXPORT_SYMBOL_GPL(dma_buf_fd);
423 * dma_buf_get - returns the dma_buf structure related to an fd
424 * @fd: [in] fd associated with the dma_buf to be returned
426 * On success, returns the dma_buf structure associated with an fd; uses
427 * file's refcounting done by fget to increase refcount. returns ERR_PTR
430 struct dma_buf *dma_buf_get(int fd)
437 return ERR_PTR(-EBADF);
439 if (!is_dma_buf_file(file)) {
441 return ERR_PTR(-EINVAL);
444 return file->private_data;
446 EXPORT_SYMBOL_GPL(dma_buf_get);
449 * dma_buf_put - decreases refcount of the buffer
450 * @dmabuf: [in] buffer to reduce refcount of
452 * Uses file's refcounting done implicitly by fput()
454 void dma_buf_put(struct dma_buf *dmabuf)
456 if (WARN_ON(!dmabuf || !dmabuf->file))
461 EXPORT_SYMBOL_GPL(dma_buf_put);
464 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
465 * calls attach() of dma_buf_ops to allow device-specific attach functionality
466 * @dmabuf: [in] buffer to attach device to.
467 * @dev: [in] device to be attached.
469 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
472 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
475 struct dma_buf_attachment *attach;
478 if (WARN_ON(!dmabuf || !dev))
479 return ERR_PTR(-EINVAL);
481 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
483 return ERR_PTR(-ENOMEM);
486 attach->dmabuf = dmabuf;
488 mutex_lock(&dmabuf->lock);
490 if (dmabuf->ops->attach) {
491 ret = dmabuf->ops->attach(dmabuf, dev, attach);
495 list_add(&attach->node, &dmabuf->attachments);
497 mutex_unlock(&dmabuf->lock);
502 mutex_unlock(&dmabuf->lock);
505 EXPORT_SYMBOL_GPL(dma_buf_attach);
508 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
509 * optionally calls detach() of dma_buf_ops for device-specific detach
510 * @dmabuf: [in] buffer to detach from.
511 * @attach: [in] attachment to be detached; is free'd after this call.
514 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
516 if (WARN_ON(!dmabuf || !attach))
519 mutex_lock(&dmabuf->lock);
520 list_del(&attach->node);
521 if (dmabuf->ops->detach)
522 dmabuf->ops->detach(dmabuf, attach);
524 mutex_unlock(&dmabuf->lock);
527 EXPORT_SYMBOL_GPL(dma_buf_detach);
530 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
531 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
533 * @attach: [in] attachment whose scatterlist is to be returned
534 * @direction: [in] direction of DMA transfer
536 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
539 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
540 enum dma_data_direction direction)
542 struct sg_table *sg_table = ERR_PTR(-EINVAL);
546 if (WARN_ON(!attach || !attach->dmabuf))
547 return ERR_PTR(-EINVAL);
549 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
551 sg_table = ERR_PTR(-ENOMEM);
555 EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
558 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
559 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
561 * @attach: [in] attachment to unmap buffer from
562 * @sg_table: [in] scatterlist info of the buffer to unmap
563 * @direction: [in] direction of DMA transfer
566 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
567 struct sg_table *sg_table,
568 enum dma_data_direction direction)
572 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
575 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
578 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
582 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
583 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
584 * preparations. Coherency is only guaranteed in the specified range for the
585 * specified access direction.
586 * @dmabuf: [in] buffer to prepare cpu access for.
587 * @direction: [in] length of range for cpu access.
589 * Can return negative error values, returns 0 on success.
591 int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
592 enum dma_data_direction direction)
596 if (WARN_ON(!dmabuf))
599 if (dmabuf->ops->begin_cpu_access)
600 ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
604 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
607 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
608 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
609 * actions. Coherency is only guaranteed in the specified range for the
610 * specified access direction.
611 * @dmabuf: [in] buffer to complete cpu access for.
612 * @direction: [in] length of range for cpu access.
614 * This call must always succeed.
616 void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
617 enum dma_data_direction direction)
621 if (dmabuf->ops->end_cpu_access)
622 dmabuf->ops->end_cpu_access(dmabuf, direction);
624 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
627 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
628 * space. The same restrictions as for kmap_atomic and friends apply.
629 * @dmabuf: [in] buffer to map page from.
630 * @page_num: [in] page in PAGE_SIZE units to map.
632 * This call must always succeed, any necessary preparations that might fail
633 * need to be done in begin_cpu_access.
635 void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
639 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
641 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
644 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
645 * @dmabuf: [in] buffer to unmap page from.
646 * @page_num: [in] page in PAGE_SIZE units to unmap.
647 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
649 * This call must always succeed.
651 void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
656 if (dmabuf->ops->kunmap_atomic)
657 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
659 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
662 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
663 * same restrictions as for kmap and friends apply.
664 * @dmabuf: [in] buffer to map page from.
665 * @page_num: [in] page in PAGE_SIZE units to map.
667 * This call must always succeed, any necessary preparations that might fail
668 * need to be done in begin_cpu_access.
670 void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
674 return dmabuf->ops->kmap(dmabuf, page_num);
676 EXPORT_SYMBOL_GPL(dma_buf_kmap);
679 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
680 * @dmabuf: [in] buffer to unmap page from.
681 * @page_num: [in] page in PAGE_SIZE units to unmap.
682 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
684 * This call must always succeed.
686 void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
691 if (dmabuf->ops->kunmap)
692 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
694 EXPORT_SYMBOL_GPL(dma_buf_kunmap);
698 * dma_buf_mmap - Setup up a userspace mmap with the given vma
699 * @dmabuf: [in] buffer that should back the vma
700 * @vma: [in] vma for the mmap
701 * @pgoff: [in] offset in pages where this mmap should start within the
704 * This function adjusts the passed in vma so that it points at the file of the
705 * dma_buf operation. It also adjusts the starting pgoff and does bounds
706 * checking on the size of the vma. Then it calls the exporters mmap function to
707 * set up the mapping.
709 * Can return negative error values, returns 0 on success.
711 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
714 struct file *oldfile;
717 if (WARN_ON(!dmabuf || !vma))
720 /* check for offset overflow */
721 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
724 /* check for overflowing the buffer's size */
725 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
726 dmabuf->size >> PAGE_SHIFT)
729 /* readjust the vma */
730 get_file(dmabuf->file);
731 oldfile = vma->vm_file;
732 vma->vm_file = dmabuf->file;
733 vma->vm_pgoff = pgoff;
735 ret = dmabuf->ops->mmap(dmabuf, vma);
737 /* restore old parameters on failure */
738 vma->vm_file = oldfile;
747 EXPORT_SYMBOL_GPL(dma_buf_mmap);
750 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
751 * address space. Same restrictions as for vmap and friends apply.
752 * @dmabuf: [in] buffer to vmap
754 * This call may fail due to lack of virtual mapping address space.
755 * These calls are optional in drivers. The intended use for them
756 * is for mapping objects linear in kernel space for high use objects.
757 * Please attempt to use kmap/kunmap before thinking about these interfaces.
759 * Returns NULL on error.
761 void *dma_buf_vmap(struct dma_buf *dmabuf)
765 if (WARN_ON(!dmabuf))
768 if (!dmabuf->ops->vmap)
771 mutex_lock(&dmabuf->lock);
772 if (dmabuf->vmapping_counter) {
773 dmabuf->vmapping_counter++;
774 BUG_ON(!dmabuf->vmap_ptr);
775 ptr = dmabuf->vmap_ptr;
779 BUG_ON(dmabuf->vmap_ptr);
781 ptr = dmabuf->ops->vmap(dmabuf);
782 if (WARN_ON_ONCE(IS_ERR(ptr)))
787 dmabuf->vmap_ptr = ptr;
788 dmabuf->vmapping_counter = 1;
791 mutex_unlock(&dmabuf->lock);
794 EXPORT_SYMBOL_GPL(dma_buf_vmap);
797 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
798 * @dmabuf: [in] buffer to vunmap
799 * @vaddr: [in] vmap to vunmap
801 void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
803 if (WARN_ON(!dmabuf))
806 BUG_ON(!dmabuf->vmap_ptr);
807 BUG_ON(dmabuf->vmapping_counter == 0);
808 BUG_ON(dmabuf->vmap_ptr != vaddr);
810 mutex_lock(&dmabuf->lock);
811 if (--dmabuf->vmapping_counter == 0) {
812 if (dmabuf->ops->vunmap)
813 dmabuf->ops->vunmap(dmabuf, vaddr);
814 dmabuf->vmap_ptr = NULL;
816 mutex_unlock(&dmabuf->lock);
818 EXPORT_SYMBOL_GPL(dma_buf_vunmap);
820 #ifdef CONFIG_DEBUG_FS
821 static int dma_buf_describe(struct seq_file *s)
824 struct dma_buf *buf_obj;
825 struct dma_buf_attachment *attach_obj;
826 int count = 0, attach_count;
829 ret = mutex_lock_interruptible(&db_list.lock);
834 seq_puts(s, "\nDma-buf Objects:\n");
835 seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
837 list_for_each_entry(buf_obj, &db_list.head, list_node) {
838 ret = mutex_lock_interruptible(&buf_obj->lock);
842 "\tERROR locking buffer object: skipping\n");
846 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
848 buf_obj->file->f_flags, buf_obj->file->f_mode,
849 file_count(buf_obj->file),
852 seq_puts(s, "\tAttached Devices:\n");
855 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
858 seq_printf(s, "%s\n", dev_name(attach_obj->dev));
862 seq_printf(s, "Total %d devices attached\n\n",
866 size += buf_obj->size;
867 mutex_unlock(&buf_obj->lock);
870 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
872 mutex_unlock(&db_list.lock);
876 static int dma_buf_show(struct seq_file *s, void *unused)
878 void (*func)(struct seq_file *) = s->private;
884 static int dma_buf_debug_open(struct inode *inode, struct file *file)
886 return single_open(file, dma_buf_show, inode->i_private);
889 static const struct file_operations dma_buf_debug_fops = {
890 .open = dma_buf_debug_open,
893 .release = single_release,
896 static struct dentry *dma_buf_debugfs_dir;
898 static int dma_buf_init_debugfs(void)
902 dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
904 if (IS_ERR(dma_buf_debugfs_dir)) {
905 err = PTR_ERR(dma_buf_debugfs_dir);
906 dma_buf_debugfs_dir = NULL;
910 err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
913 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
918 static void dma_buf_uninit_debugfs(void)
920 if (dma_buf_debugfs_dir)
921 debugfs_remove_recursive(dma_buf_debugfs_dir);
924 int dma_buf_debugfs_create_file(const char *name,
925 int (*write)(struct seq_file *))
929 d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
930 write, &dma_buf_debug_fops);
932 return PTR_ERR_OR_ZERO(d);
935 static inline int dma_buf_init_debugfs(void)
939 static inline void dma_buf_uninit_debugfs(void)
944 static int __init dma_buf_init(void)
946 mutex_init(&db_list.lock);
947 INIT_LIST_HEAD(&db_list.head);
948 dma_buf_init_debugfs();
951 subsys_initcall(dma_buf_init);
953 static void __exit dma_buf_deinit(void)
955 dma_buf_uninit_debugfs();
957 __exitcall(dma_buf_deinit);