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>
38 #include <uapi/linux/dma-buf.h>
40 static inline int is_dma_buf_file(struct file *);
43 struct list_head head;
47 static struct dma_buf_list db_list;
49 static int dma_buf_release(struct inode *inode, struct file *file)
51 struct dma_buf *dmabuf;
53 if (!is_dma_buf_file(file))
56 dmabuf = file->private_data;
58 BUG_ON(dmabuf->vmapping_counter);
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.
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.
68 BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
70 dmabuf->ops->release(dmabuf);
72 mutex_lock(&db_list.lock);
73 list_del(&dmabuf->list_node);
74 mutex_unlock(&db_list.lock);
76 if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
77 reservation_object_fini(dmabuf->resv);
79 module_put(dmabuf->owner);
84 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
86 struct dma_buf *dmabuf;
88 if (!is_dma_buf_file(file))
91 dmabuf = file->private_data;
93 /* check for overflowing the buffer's size */
94 if (vma->vm_pgoff + vma_pages(vma) >
95 dmabuf->size >> PAGE_SHIFT)
98 return dmabuf->ops->mmap(dmabuf, vma);
101 static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
103 struct dma_buf *dmabuf;
106 if (!is_dma_buf_file(file))
109 dmabuf = file->private_data;
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)
116 else if (whence == SEEK_SET)
124 return base + offset;
127 static void dma_buf_poll_cb(struct fence *fence, struct fence_cb *cb)
129 struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
132 spin_lock_irqsave(&dcb->poll->lock, flags);
133 wake_up_locked_poll(dcb->poll, dcb->active);
135 spin_unlock_irqrestore(&dcb->poll->lock, flags);
138 static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
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;
147 dmabuf = file->private_data;
148 if (!dmabuf || !dmabuf->resv)
153 poll_wait(file, &dmabuf->poll, poll);
155 events = poll_requested_events(poll) & (POLLIN | POLLOUT);
160 seq = read_seqcount_begin(&resv->seq);
163 fobj = rcu_dereference(resv->fence);
165 shared_count = fobj->shared_count;
168 fence_excl = rcu_dereference(resv->fence_excl);
169 if (read_seqcount_retry(&resv->seq, seq)) {
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;
178 if (shared_count == 0)
181 spin_lock_irq(&dmabuf->poll.lock);
183 dcb->active |= pevents;
186 dcb->active = pevents;
187 spin_unlock_irq(&dmabuf->poll.lock);
189 if (events & pevents) {
190 if (!fence_get_rcu(fence_excl)) {
191 /* force a recheck */
193 dma_buf_poll_cb(NULL, &dcb->cb);
194 } else if (!fence_add_callback(fence_excl, &dcb->cb,
197 fence_put(fence_excl);
200 * No callback queued, wake up any additional
203 fence_put(fence_excl);
204 dma_buf_poll_cb(NULL, &dcb->cb);
209 if ((events & POLLOUT) && shared_count > 0) {
210 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
213 /* Only queue a new callback if no event has fired yet */
214 spin_lock_irq(&dmabuf->poll.lock);
218 dcb->active = POLLOUT;
219 spin_unlock_irq(&dmabuf->poll.lock);
221 if (!(events & POLLOUT))
224 for (i = 0; i < shared_count; ++i) {
225 struct fence *fence = rcu_dereference(fobj->shared[i]);
227 if (!fence_get_rcu(fence)) {
229 * fence refcount dropped to zero, this means
230 * that fobj has been freed
232 * call dma_buf_poll_cb and force a recheck!
235 dma_buf_poll_cb(NULL, &dcb->cb);
238 if (!fence_add_callback(fence, &dcb->cb,
247 /* No callback queued, wake up any additional waiters. */
248 if (i == shared_count)
249 dma_buf_poll_cb(NULL, &dcb->cb);
257 static long dma_buf_ioctl(struct file *file,
258 unsigned int cmd, unsigned long arg)
260 struct dma_buf *dmabuf;
261 struct dma_buf_sync sync;
262 enum dma_data_direction direction;
265 dmabuf = file->private_data;
268 case DMA_BUF_IOCTL_SYNC:
269 if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
272 if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
275 switch (sync.flags & DMA_BUF_SYNC_RW) {
276 case DMA_BUF_SYNC_READ:
277 direction = DMA_FROM_DEVICE;
279 case DMA_BUF_SYNC_WRITE:
280 direction = DMA_TO_DEVICE;
282 case DMA_BUF_SYNC_RW:
283 direction = DMA_BIDIRECTIONAL;
289 if (sync.flags & DMA_BUF_SYNC_END)
290 ret = dma_buf_end_cpu_access(dmabuf, direction);
292 ret = dma_buf_begin_cpu_access(dmabuf, direction);
300 static 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,
309 * is_dma_buf_file - Check if struct file* is associated with dma_buf
311 static inline int is_dma_buf_file(struct file *file)
313 return file->f_op == &dma_buf_fops;
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.
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.
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.
331 struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
333 struct dma_buf *dmabuf;
334 struct reservation_object *resv = exp_info->resv;
336 size_t alloc_size = sizeof(struct dma_buf);
339 alloc_size += sizeof(struct reservation_object);
341 /* prevent &dma_buf[1] == dma_buf->resv */
344 if (WARN_ON(!exp_info->priv
346 || !exp_info->ops->map_dma_buf
347 || !exp_info->ops->unmap_dma_buf
348 || !exp_info->ops->release
349 || !exp_info->ops->kmap_atomic
350 || !exp_info->ops->kmap
351 || !exp_info->ops->mmap)) {
352 return ERR_PTR(-EINVAL);
355 if (!try_module_get(exp_info->owner))
356 return ERR_PTR(-ENOENT);
358 dmabuf = kzalloc(alloc_size, GFP_KERNEL);
360 module_put(exp_info->owner);
361 return ERR_PTR(-ENOMEM);
364 dmabuf->priv = exp_info->priv;
365 dmabuf->ops = exp_info->ops;
366 dmabuf->size = exp_info->size;
367 dmabuf->exp_name = exp_info->exp_name;
368 dmabuf->owner = exp_info->owner;
369 init_waitqueue_head(&dmabuf->poll);
370 dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
371 dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
374 resv = (struct reservation_object *)&dmabuf[1];
375 reservation_object_init(resv);
379 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
383 return ERR_CAST(file);
386 file->f_mode |= FMODE_LSEEK;
389 mutex_init(&dmabuf->lock);
390 INIT_LIST_HEAD(&dmabuf->attachments);
392 mutex_lock(&db_list.lock);
393 list_add(&dmabuf->list_node, &db_list.head);
394 mutex_unlock(&db_list.lock);
398 EXPORT_SYMBOL_GPL(dma_buf_export);
401 * dma_buf_fd - returns a file descriptor for the given dma_buf
402 * @dmabuf: [in] pointer to dma_buf for which fd is required.
403 * @flags: [in] flags to give to fd
405 * On success, returns an associated 'fd'. Else, returns error.
407 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
411 if (!dmabuf || !dmabuf->file)
414 fd = get_unused_fd_flags(flags);
418 fd_install(fd, dmabuf->file);
422 EXPORT_SYMBOL_GPL(dma_buf_fd);
425 * dma_buf_get - returns the dma_buf structure related to an fd
426 * @fd: [in] fd associated with the dma_buf to be returned
428 * On success, returns the dma_buf structure associated with an fd; uses
429 * file's refcounting done by fget to increase refcount. returns ERR_PTR
432 struct dma_buf *dma_buf_get(int fd)
439 return ERR_PTR(-EBADF);
441 if (!is_dma_buf_file(file)) {
443 return ERR_PTR(-EINVAL);
446 return file->private_data;
448 EXPORT_SYMBOL_GPL(dma_buf_get);
451 * dma_buf_put - decreases refcount of the buffer
452 * @dmabuf: [in] buffer to reduce refcount of
454 * Uses file's refcounting done implicitly by fput()
456 void dma_buf_put(struct dma_buf *dmabuf)
458 if (WARN_ON(!dmabuf || !dmabuf->file))
463 EXPORT_SYMBOL_GPL(dma_buf_put);
466 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
467 * calls attach() of dma_buf_ops to allow device-specific attach functionality
468 * @dmabuf: [in] buffer to attach device to.
469 * @dev: [in] device to be attached.
471 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
474 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
477 struct dma_buf_attachment *attach;
480 if (WARN_ON(!dmabuf || !dev))
481 return ERR_PTR(-EINVAL);
483 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
485 return ERR_PTR(-ENOMEM);
488 attach->dmabuf = dmabuf;
490 mutex_lock(&dmabuf->lock);
492 if (dmabuf->ops->attach) {
493 ret = dmabuf->ops->attach(dmabuf, dev, attach);
497 list_add(&attach->node, &dmabuf->attachments);
499 mutex_unlock(&dmabuf->lock);
504 mutex_unlock(&dmabuf->lock);
507 EXPORT_SYMBOL_GPL(dma_buf_attach);
510 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
511 * optionally calls detach() of dma_buf_ops for device-specific detach
512 * @dmabuf: [in] buffer to detach from.
513 * @attach: [in] attachment to be detached; is free'd after this call.
516 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
518 if (WARN_ON(!dmabuf || !attach))
521 mutex_lock(&dmabuf->lock);
522 list_del(&attach->node);
523 if (dmabuf->ops->detach)
524 dmabuf->ops->detach(dmabuf, attach);
526 mutex_unlock(&dmabuf->lock);
529 EXPORT_SYMBOL_GPL(dma_buf_detach);
532 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
533 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
535 * @attach: [in] attachment whose scatterlist is to be returned
536 * @direction: [in] direction of DMA transfer
538 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
541 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
542 enum dma_data_direction direction)
544 struct sg_table *sg_table = ERR_PTR(-EINVAL);
548 if (WARN_ON(!attach || !attach->dmabuf))
549 return ERR_PTR(-EINVAL);
551 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
553 sg_table = ERR_PTR(-ENOMEM);
557 EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
560 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
561 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
563 * @attach: [in] attachment to unmap buffer from
564 * @sg_table: [in] scatterlist info of the buffer to unmap
565 * @direction: [in] direction of DMA transfer
568 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
569 struct sg_table *sg_table,
570 enum dma_data_direction direction)
574 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
577 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
580 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
584 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
585 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
586 * preparations. Coherency is only guaranteed in the specified range for the
587 * specified access direction.
588 * @dmabuf: [in] buffer to prepare cpu access for.
589 * @direction: [in] length of range for cpu access.
591 * Can return negative error values, returns 0 on success.
593 int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
594 enum dma_data_direction direction)
598 if (WARN_ON(!dmabuf))
601 if (dmabuf->ops->begin_cpu_access)
602 ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
606 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
609 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
610 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
611 * actions. Coherency is only guaranteed in the specified range for the
612 * specified access direction.
613 * @dmabuf: [in] buffer to complete cpu access for.
614 * @direction: [in] length of range for cpu access.
616 * Can return negative error values, returns 0 on success.
618 int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
619 enum dma_data_direction direction)
625 if (dmabuf->ops->end_cpu_access)
626 ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
630 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
633 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
634 * space. The same restrictions as for kmap_atomic and friends apply.
635 * @dmabuf: [in] buffer to map page from.
636 * @page_num: [in] page in PAGE_SIZE units to map.
638 * This call must always succeed, any necessary preparations that might fail
639 * need to be done in begin_cpu_access.
641 void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
645 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
647 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
650 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
651 * @dmabuf: [in] buffer to unmap page from.
652 * @page_num: [in] page in PAGE_SIZE units to unmap.
653 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
655 * This call must always succeed.
657 void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
662 if (dmabuf->ops->kunmap_atomic)
663 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
665 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
668 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
669 * same restrictions as for kmap and friends apply.
670 * @dmabuf: [in] buffer to map page from.
671 * @page_num: [in] page in PAGE_SIZE units to map.
673 * This call must always succeed, any necessary preparations that might fail
674 * need to be done in begin_cpu_access.
676 void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
680 return dmabuf->ops->kmap(dmabuf, page_num);
682 EXPORT_SYMBOL_GPL(dma_buf_kmap);
685 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
686 * @dmabuf: [in] buffer to unmap page from.
687 * @page_num: [in] page in PAGE_SIZE units to unmap.
688 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
690 * This call must always succeed.
692 void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
697 if (dmabuf->ops->kunmap)
698 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
700 EXPORT_SYMBOL_GPL(dma_buf_kunmap);
704 * dma_buf_mmap - Setup up a userspace mmap with the given vma
705 * @dmabuf: [in] buffer that should back the vma
706 * @vma: [in] vma for the mmap
707 * @pgoff: [in] offset in pages where this mmap should start within the
710 * This function adjusts the passed in vma so that it points at the file of the
711 * dma_buf operation. It also adjusts the starting pgoff and does bounds
712 * checking on the size of the vma. Then it calls the exporters mmap function to
713 * set up the mapping.
715 * Can return negative error values, returns 0 on success.
717 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
720 struct file *oldfile;
723 if (WARN_ON(!dmabuf || !vma))
726 /* check for offset overflow */
727 if (pgoff + vma_pages(vma) < pgoff)
730 /* check for overflowing the buffer's size */
731 if (pgoff + vma_pages(vma) >
732 dmabuf->size >> PAGE_SHIFT)
735 /* readjust the vma */
736 get_file(dmabuf->file);
737 oldfile = vma->vm_file;
738 vma->vm_file = dmabuf->file;
739 vma->vm_pgoff = pgoff;
741 ret = dmabuf->ops->mmap(dmabuf, vma);
743 /* restore old parameters on failure */
744 vma->vm_file = oldfile;
753 EXPORT_SYMBOL_GPL(dma_buf_mmap);
756 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
757 * address space. Same restrictions as for vmap and friends apply.
758 * @dmabuf: [in] buffer to vmap
760 * This call may fail due to lack of virtual mapping address space.
761 * These calls are optional in drivers. The intended use for them
762 * is for mapping objects linear in kernel space for high use objects.
763 * Please attempt to use kmap/kunmap before thinking about these interfaces.
765 * Returns NULL on error.
767 void *dma_buf_vmap(struct dma_buf *dmabuf)
771 if (WARN_ON(!dmabuf))
774 if (!dmabuf->ops->vmap)
777 mutex_lock(&dmabuf->lock);
778 if (dmabuf->vmapping_counter) {
779 dmabuf->vmapping_counter++;
780 BUG_ON(!dmabuf->vmap_ptr);
781 ptr = dmabuf->vmap_ptr;
785 BUG_ON(dmabuf->vmap_ptr);
787 ptr = dmabuf->ops->vmap(dmabuf);
788 if (WARN_ON_ONCE(IS_ERR(ptr)))
793 dmabuf->vmap_ptr = ptr;
794 dmabuf->vmapping_counter = 1;
797 mutex_unlock(&dmabuf->lock);
800 EXPORT_SYMBOL_GPL(dma_buf_vmap);
803 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
804 * @dmabuf: [in] buffer to vunmap
805 * @vaddr: [in] vmap to vunmap
807 void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
809 if (WARN_ON(!dmabuf))
812 BUG_ON(!dmabuf->vmap_ptr);
813 BUG_ON(dmabuf->vmapping_counter == 0);
814 BUG_ON(dmabuf->vmap_ptr != vaddr);
816 mutex_lock(&dmabuf->lock);
817 if (--dmabuf->vmapping_counter == 0) {
818 if (dmabuf->ops->vunmap)
819 dmabuf->ops->vunmap(dmabuf, vaddr);
820 dmabuf->vmap_ptr = NULL;
822 mutex_unlock(&dmabuf->lock);
824 EXPORT_SYMBOL_GPL(dma_buf_vunmap);
826 #ifdef CONFIG_DEBUG_FS
827 static int dma_buf_describe(struct seq_file *s)
830 struct dma_buf *buf_obj;
831 struct dma_buf_attachment *attach_obj;
832 int count = 0, attach_count;
835 ret = mutex_lock_interruptible(&db_list.lock);
840 seq_puts(s, "\nDma-buf Objects:\n");
841 seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
843 list_for_each_entry(buf_obj, &db_list.head, list_node) {
844 ret = mutex_lock_interruptible(&buf_obj->lock);
848 "\tERROR locking buffer object: skipping\n");
852 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
854 buf_obj->file->f_flags, buf_obj->file->f_mode,
855 file_count(buf_obj->file),
858 seq_puts(s, "\tAttached Devices:\n");
861 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
864 seq_printf(s, "%s\n", dev_name(attach_obj->dev));
868 seq_printf(s, "Total %d devices attached\n\n",
872 size += buf_obj->size;
873 mutex_unlock(&buf_obj->lock);
876 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
878 mutex_unlock(&db_list.lock);
882 static int dma_buf_show(struct seq_file *s, void *unused)
884 void (*func)(struct seq_file *) = s->private;
890 static int dma_buf_debug_open(struct inode *inode, struct file *file)
892 return single_open(file, dma_buf_show, inode->i_private);
895 static const struct file_operations dma_buf_debug_fops = {
896 .open = dma_buf_debug_open,
899 .release = single_release,
902 static struct dentry *dma_buf_debugfs_dir;
904 static int dma_buf_init_debugfs(void)
908 dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
910 if (IS_ERR(dma_buf_debugfs_dir)) {
911 err = PTR_ERR(dma_buf_debugfs_dir);
912 dma_buf_debugfs_dir = NULL;
916 err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
919 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
924 static void dma_buf_uninit_debugfs(void)
926 if (dma_buf_debugfs_dir)
927 debugfs_remove_recursive(dma_buf_debugfs_dir);
930 int dma_buf_debugfs_create_file(const char *name,
931 int (*write)(struct seq_file *))
935 d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
936 write, &dma_buf_debug_fops);
938 return PTR_ERR_OR_ZERO(d);
941 static inline int dma_buf_init_debugfs(void)
945 static inline void dma_buf_uninit_debugfs(void)
950 static int __init dma_buf_init(void)
952 mutex_init(&db_list.lock);
953 INIT_LIST_HEAD(&db_list.head);
954 dma_buf_init_debugfs();
957 subsys_initcall(dma_buf_init);
959 static void __exit dma_buf_deinit(void)
961 dma_buf_uninit_debugfs();
963 __exitcall(dma_buf_deinit);