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1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Header file for dma buffer sharing framework.
4  *
5  * Copyright(C) 2011 Linaro Limited. All rights reserved.
6  * Author: Sumit Semwal <sumit.semwal@ti.com>
7  *
8  * Many thanks to linaro-mm-sig list, and specially
9  * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
10  * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
11  * refining of this idea.
12  */
13 #ifndef __DMA_BUF_H__
14 #define __DMA_BUF_H__
15 
16 #include <linux/file.h>
17 #include <linux/err.h>
18 #include <linux/scatterlist.h>
19 #include <linux/list.h>
20 #include <linux/dma-mapping.h>
21 #include <linux/fs.h>
22 #include <linux/dma-fence.h>
23 #include <linux/wait.h>
24 #include <linux/android_kabi.h>
25 
26 struct device;
27 struct dma_buf;
28 struct dma_buf_attachment;
29 
30 /**
31  * struct dma_buf_ops - operations possible on struct dma_buf
32  * @vmap: [optional] creates a virtual mapping for the buffer into kernel
33  *	  address space. Same restrictions as for vmap and friends apply.
34  * @vunmap: [optional] unmaps a vmap from the buffer
35  */
36 struct dma_buf_ops {
37 	/**
38 	  * @cache_sgt_mapping:
39 	  *
40 	  * If true the framework will cache the first mapping made for each
41 	  * attachment. This avoids creating mappings for attachments multiple
42 	  * times.
43 	  */
44 	bool cache_sgt_mapping;
45 
46 	/**
47 	 * @attach:
48 	 *
49 	 * This is called from dma_buf_attach() to make sure that a given
50 	 * &dma_buf_attachment.dev can access the provided &dma_buf. Exporters
51 	 * which support buffer objects in special locations like VRAM or
52 	 * device-specific carveout areas should check whether the buffer could
53 	 * be move to system memory (or directly accessed by the provided
54 	 * device), and otherwise need to fail the attach operation.
55 	 *
56 	 * The exporter should also in general check whether the current
57 	 * allocation fullfills the DMA constraints of the new device. If this
58 	 * is not the case, and the allocation cannot be moved, it should also
59 	 * fail the attach operation.
60 	 *
61 	 * Any exporter-private housekeeping data can be stored in the
62 	 * &dma_buf_attachment.priv pointer.
63 	 *
64 	 * This callback is optional.
65 	 *
66 	 * Returns:
67 	 *
68 	 * 0 on success, negative error code on failure. It might return -EBUSY
69 	 * to signal that backing storage is already allocated and incompatible
70 	 * with the requirements of requesting device.
71 	 */
72 	int (*attach)(struct dma_buf *, struct dma_buf_attachment *);
73 
74 	/**
75 	 * @detach:
76 	 *
77 	 * This is called by dma_buf_detach() to release a &dma_buf_attachment.
78 	 * Provided so that exporters can clean up any housekeeping for an
79 	 * &dma_buf_attachment.
80 	 *
81 	 * This callback is optional.
82 	 */
83 	void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
84 
85 	/**
86 	 * @pin:
87 	 *
88 	 * This is called by dma_buf_pin and lets the exporter know that the
89 	 * DMA-buf can't be moved any more.
90 	 *
91 	 * This is called with the dmabuf->resv object locked and is mutual
92 	 * exclusive with @cache_sgt_mapping.
93 	 *
94 	 * This callback is optional and should only be used in limited use
95 	 * cases like scanout and not for temporary pin operations.
96 	 *
97 	 * Returns:
98 	 *
99 	 * 0 on success, negative error code on failure.
100 	 */
101 	int (*pin)(struct dma_buf_attachment *attach);
102 
103 	/**
104 	 * @unpin:
105 	 *
106 	 * This is called by dma_buf_unpin and lets the exporter know that the
107 	 * DMA-buf can be moved again.
108 	 *
109 	 * This is called with the dmabuf->resv object locked and is mutual
110 	 * exclusive with @cache_sgt_mapping.
111 	 *
112 	 * This callback is optional.
113 	 */
114 	void (*unpin)(struct dma_buf_attachment *attach);
115 
116 	/**
117 	 * @map_dma_buf:
118 	 *
119 	 * This is called by dma_buf_map_attachment() and is used to map a
120 	 * shared &dma_buf into device address space, and it is mandatory. It
121 	 * can only be called if @attach has been called successfully.
122 	 *
123 	 * This call may sleep, e.g. when the backing storage first needs to be
124 	 * allocated, or moved to a location suitable for all currently attached
125 	 * devices.
126 	 *
127 	 * Note that any specific buffer attributes required for this function
128 	 * should get added to device_dma_parameters accessible via
129 	 * &device.dma_params from the &dma_buf_attachment. The @attach callback
130 	 * should also check these constraints.
131 	 *
132 	 * If this is being called for the first time, the exporter can now
133 	 * choose to scan through the list of attachments for this buffer,
134 	 * collate the requirements of the attached devices, and choose an
135 	 * appropriate backing storage for the buffer.
136 	 *
137 	 * Based on enum dma_data_direction, it might be possible to have
138 	 * multiple users accessing at the same time (for reading, maybe), or
139 	 * any other kind of sharing that the exporter might wish to make
140 	 * available to buffer-users.
141 	 *
142 	 * This is always called with the dmabuf->resv object locked when
143 	 * the dynamic_mapping flag is true.
144 	 *
145 	 * Returns:
146 	 *
147 	 * A &sg_table scatter list of or the backing storage of the DMA buffer,
148 	 * already mapped into the device address space of the &device attached
149 	 * with the provided &dma_buf_attachment.
150 	 *
151 	 * On failure, returns a negative error value wrapped into a pointer.
152 	 * May also return -EINTR when a signal was received while being
153 	 * blocked.
154 	 */
155 	struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
156 					 enum dma_data_direction);
157 	/**
158 	 * @unmap_dma_buf:
159 	 *
160 	 * This is called by dma_buf_unmap_attachment() and should unmap and
161 	 * release the &sg_table allocated in @map_dma_buf, and it is mandatory.
162 	 * For static dma_buf handling this might also unpins the backing
163 	 * storage if this is the last mapping of the DMA buffer.
164 	 */
165 	void (*unmap_dma_buf)(struct dma_buf_attachment *,
166 			      struct sg_table *,
167 			      enum dma_data_direction);
168 
169 	/* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
170 	 * if the call would block.
171 	 */
172 
173 	/**
174 	 * @release:
175 	 *
176 	 * Called after the last dma_buf_put to release the &dma_buf, and
177 	 * mandatory.
178 	 */
179 	void (*release)(struct dma_buf *);
180 
181 	/**
182 	 * @begin_cpu_access:
183 	 *
184 	 * This is called from dma_buf_begin_cpu_access() and allows the
185 	 * exporter to ensure that the memory is actually available for cpu
186 	 * access - the exporter might need to allocate or swap-in and pin the
187 	 * backing storage. The exporter also needs to ensure that cpu access is
188 	 * coherent for the access direction. The direction can be used by the
189 	 * exporter to optimize the cache flushing, i.e. access with a different
190 	 * direction (read instead of write) might return stale or even bogus
191 	 * data (e.g. when the exporter needs to copy the data to temporary
192 	 * storage).
193 	 *
194 	 * This callback is optional.
195 	 *
196 	 * FIXME: This is both called through the DMA_BUF_IOCTL_SYNC command
197 	 * from userspace (where storage shouldn't be pinned to avoid handing
198 	 * de-factor mlock rights to userspace) and for the kernel-internal
199 	 * users of the various kmap interfaces, where the backing storage must
200 	 * be pinned to guarantee that the atomic kmap calls can succeed. Since
201 	 * there's no in-kernel users of the kmap interfaces yet this isn't a
202 	 * real problem.
203 	 *
204 	 * Returns:
205 	 *
206 	 * 0 on success or a negative error code on failure. This can for
207 	 * example fail when the backing storage can't be allocated. Can also
208 	 * return -ERESTARTSYS or -EINTR when the call has been interrupted and
209 	 * needs to be restarted.
210 	 */
211 	int (*begin_cpu_access)(struct dma_buf *, enum dma_data_direction);
212 
213 	/**
214 	 * @begin_cpu_access_partial:
215 	 *
216 	 * This is called from dma_buf_begin_cpu_access_partial() and allows the
217 	 * exporter to ensure that the memory specified in the range is
218 	 * available for cpu access - the exporter might need to allocate or
219 	 * swap-in and pin the backing storage.
220 	 * The exporter also needs to ensure that cpu access is
221 	 * coherent for the access direction. The direction can be used by the
222 	 * exporter to optimize the cache flushing, i.e. access with a different
223 	 * direction (read instead of write) might return stale or even bogus
224 	 * data (e.g. when the exporter needs to copy the data to temporary
225 	 * storage).
226 	 *
227 	 * This callback is optional.
228 	 *
229 	 * FIXME: This is both called through the DMA_BUF_IOCTL_SYNC command
230 	 * from userspace (where storage shouldn't be pinned to avoid handing
231 	 * de-factor mlock rights to userspace) and for the kernel-internal
232 	 * users of the various kmap interfaces, where the backing storage must
233 	 * be pinned to guarantee that the atomic kmap calls can succeed. Since
234 	 * there's no in-kernel users of the kmap interfaces yet this isn't a
235 	 * real problem.
236 	 *
237 	 * Returns:
238 	 *
239 	 * 0 on success or a negative error code on failure. This can for
240 	 * example fail when the backing storage can't be allocated. Can also
241 	 * return -ERESTARTSYS or -EINTR when the call has been interrupted and
242 	 * needs to be restarted.
243 	 */
244 	int (*begin_cpu_access_partial)(struct dma_buf *dmabuf,
245 					enum dma_data_direction,
246 					unsigned int offset, unsigned int len);
247 
248 	/**
249 	 * @end_cpu_access:
250 	 *
251 	 * This is called from dma_buf_end_cpu_access() when the importer is
252 	 * done accessing the CPU. The exporter can use this to flush caches and
253 	 * unpin any resources pinned in @begin_cpu_access.
254 	 * The result of any dma_buf kmap calls after end_cpu_access is
255 	 * undefined.
256 	 *
257 	 * This callback is optional.
258 	 *
259 	 * Returns:
260 	 *
261 	 * 0 on success or a negative error code on failure. Can return
262 	 * -ERESTARTSYS or -EINTR when the call has been interrupted and needs
263 	 * to be restarted.
264 	 */
265 	int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
266 
267 	/**
268 	 * @end_cpu_access_partial:
269 	 *
270 	 * This is called from dma_buf_end_cpu_access_partial() when the
271 	 * importer is done accessing the CPU. The exporter can use to limit
272 	 * cache flushing to only the range specefied and to unpin any
273 	 * resources pinned in @begin_cpu_access_umapped.
274 	 * The result of any dma_buf kmap calls after end_cpu_access_partial is
275 	 * undefined.
276 	 *
277 	 * This callback is optional.
278 	 *
279 	 * Returns:
280 	 *
281 	 * 0 on success or a negative error code on failure. Can return
282 	 * -ERESTARTSYS or -EINTR when the call has been interrupted and needs
283 	 * to be restarted.
284 	 */
285 	int (*end_cpu_access_partial)(struct dma_buf *dmabuf,
286 				      enum dma_data_direction,
287 				      unsigned int offset, unsigned int len);
288 
289 	/**
290 	 * @mmap:
291 	 *
292 	 * This callback is used by the dma_buf_mmap() function
293 	 *
294 	 * Note that the mapping needs to be incoherent, userspace is expected
295 	 * to braket CPU access using the DMA_BUF_IOCTL_SYNC interface.
296 	 *
297 	 * Because dma-buf buffers have invariant size over their lifetime, the
298 	 * dma-buf core checks whether a vma is too large and rejects such
299 	 * mappings. The exporter hence does not need to duplicate this check.
300 	 * Drivers do not need to check this themselves.
301 	 *
302 	 * If an exporter needs to manually flush caches and hence needs to fake
303 	 * coherency for mmap support, it needs to be able to zap all the ptes
304 	 * pointing at the backing storage. Now linux mm needs a struct
305 	 * address_space associated with the struct file stored in vma->vm_file
306 	 * to do that with the function unmap_mapping_range. But the dma_buf
307 	 * framework only backs every dma_buf fd with the anon_file struct file,
308 	 * i.e. all dma_bufs share the same file.
309 	 *
310 	 * Hence exporters need to setup their own file (and address_space)
311 	 * association by setting vma->vm_file and adjusting vma->vm_pgoff in
312 	 * the dma_buf mmap callback. In the specific case of a gem driver the
313 	 * exporter could use the shmem file already provided by gem (and set
314 	 * vm_pgoff = 0). Exporters can then zap ptes by unmapping the
315 	 * corresponding range of the struct address_space associated with their
316 	 * own file.
317 	 *
318 	 * This callback is optional.
319 	 *
320 	 * Returns:
321 	 *
322 	 * 0 on success or a negative error code on failure.
323 	 */
324 	int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
325 
326 	void *(*vmap)(struct dma_buf *);
327 	void (*vunmap)(struct dma_buf *, void *vaddr);
328 
329 	/**
330 	 * @get_uuid
331 	 *
332 	 * This is called by dma_buf_get_uuid to get the UUID which identifies
333 	 * the buffer to virtio devices.
334 	 *
335 	 * This callback is optional.
336 	 *
337 	 * Returns:
338 	 *
339 	 * 0 on success or a negative error code on failure. On success uuid
340 	 * will be populated with the buffer's UUID.
341 	 */
342 	int (*get_uuid)(struct dma_buf *dmabuf, uuid_t *uuid);
343 
344 	/**
345 	 * @get_flags:
346 	 *
347 	 * This is called by dma_buf_get_flags and is used to get the buffer's
348 	 * flags.
349 	 * This callback is optional.
350 	 *
351 	 * Returns:
352 	 *
353 	 * 0 on success or a negative error code on failure. On success flags
354 	 * will be populated with the buffer's flags.
355 	 */
356 	int (*get_flags)(struct dma_buf *dmabuf, unsigned long *flags);
357 
358 	ANDROID_KABI_RESERVE(1);
359 	ANDROID_KABI_RESERVE(2);
360 };
361 
362 /**
363  * struct dma_buf - shared buffer object
364  * @size: size of the buffer
365  * @file: file pointer used for sharing buffers across, and for refcounting.
366  * @attachments: list of dma_buf_attachment that denotes all devices attached,
367  *               protected by dma_resv lock.
368  * @ops: dma_buf_ops associated with this buffer object.
369  * @lock: used internally to serialize list manipulation, attach/detach and
370  *        vmap/unmap
371  * @vmapping_counter: used internally to refcnt the vmaps
372  * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
373  * @exp_name: name of the exporter; useful for debugging.
374  * @name: userspace-provided name; useful for accounting and debugging,
375  *        protected by @resv.
376  * @name_lock: spinlock to protect name access
377  * @owner: pointer to exporter module; used for refcounting when exporter is a
378  *         kernel module.
379  * @list_node: node for dma_buf accounting and debugging.
380  * @priv: exporter specific private data for this buffer object.
381  * @resv: reservation object linked to this dma-buf
382  * @poll: for userspace poll support
383  * @cb_excl: for userspace poll support
384  * @cb_shared: for userspace poll support
385  * @sysfs_entry: for exposing information about this buffer in sysfs.
386  *
387  * This represents a shared buffer, created by calling dma_buf_export(). The
388  * userspace representation is a normal file descriptor, which can be created by
389  * calling dma_buf_fd().
390  *
391  * Shared dma buffers are reference counted using dma_buf_put() and
392  * get_dma_buf().
393  *
394  * Device DMA access is handled by the separate &struct dma_buf_attachment.
395  */
396 struct dma_buf {
397 	size_t size;
398 	struct file *file;
399 	struct list_head attachments;
400 	const struct dma_buf_ops *ops;
401 	struct mutex lock;
402 	unsigned vmapping_counter;
403 	void *vmap_ptr;
404 	const char *exp_name;
405 	const char *name;
406 	spinlock_t name_lock;
407 	struct module *owner;
408 	struct list_head list_node;
409 	void *priv;
410 	struct dma_resv *resv;
411 
412 	/* poll support */
413 	wait_queue_head_t poll;
414 
415 	struct dma_buf_poll_cb_t {
416 		struct dma_fence_cb cb;
417 		wait_queue_head_t *poll;
418 
419 		__poll_t active;
420 	} cb_excl, cb_shared;
421 #ifdef CONFIG_DMABUF_SYSFS_STATS
422 	/* for sysfs stats */
423 	struct dma_buf_sysfs_entry {
424 		struct kobject kobj;
425 		struct dma_buf *dmabuf;
426 	} *sysfs_entry;
427 #endif
428 
429 	ANDROID_KABI_RESERVE(1);
430 	ANDROID_KABI_RESERVE(2);
431 };
432 
433 /**
434  * struct dma_buf_attach_ops - importer operations for an attachment
435  *
436  * Attachment operations implemented by the importer.
437  */
438 struct dma_buf_attach_ops {
439 	/**
440 	 * @allow_peer2peer:
441 	 *
442 	 * If this is set to true the importer must be able to handle peer
443 	 * resources without struct pages.
444 	 */
445 	bool allow_peer2peer;
446 
447 	/**
448 	 * @move_notify: [optional] notification that the DMA-buf is moving
449 	 *
450 	 * If this callback is provided the framework can avoid pinning the
451 	 * backing store while mappings exists.
452 	 *
453 	 * This callback is called with the lock of the reservation object
454 	 * associated with the dma_buf held and the mapping function must be
455 	 * called with this lock held as well. This makes sure that no mapping
456 	 * is created concurrently with an ongoing move operation.
457 	 *
458 	 * Mappings stay valid and are not directly affected by this callback.
459 	 * But the DMA-buf can now be in a different physical location, so all
460 	 * mappings should be destroyed and re-created as soon as possible.
461 	 *
462 	 * New mappings can be created after this callback returns, and will
463 	 * point to the new location of the DMA-buf.
464 	 */
465 	void (*move_notify)(struct dma_buf_attachment *attach);
466 };
467 
468 /**
469  * struct dma_buf_attachment - holds device-buffer attachment data
470  * @dmabuf: buffer for this attachment.
471  * @dev: device attached to the buffer.
472  * @node: list of dma_buf_attachment, protected by dma_resv lock of the dmabuf.
473  * @sgt: cached mapping.
474  * @dir: direction of cached mapping.
475  * @peer2peer: true if the importer can handle peer resources without pages.
476  * @priv: exporter specific attachment data.
477  * @importer_ops: importer operations for this attachment, if provided
478  * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held.
479  * @importer_priv: importer specific attachment data.
480  * @dma_map_attrs: DMA attributes to be used when the exporter maps the buffer
481  * through dma_buf_map_attachment.
482  *
483  * This structure holds the attachment information between the dma_buf buffer
484  * and its user device(s). The list contains one attachment struct per device
485  * attached to the buffer.
486  *
487  * An attachment is created by calling dma_buf_attach(), and released again by
488  * calling dma_buf_detach(). The DMA mapping itself needed to initiate a
489  * transfer is created by dma_buf_map_attachment() and freed again by calling
490  * dma_buf_unmap_attachment().
491  */
492 struct dma_buf_attachment {
493 	struct dma_buf *dmabuf;
494 	struct device *dev;
495 	struct list_head node;
496 	struct sg_table *sgt;
497 	enum dma_data_direction dir;
498 	bool peer2peer;
499 	const struct dma_buf_attach_ops *importer_ops;
500 	void *importer_priv;
501 	void *priv;
502 	unsigned long dma_map_attrs;
503 
504 	ANDROID_KABI_RESERVE(1);
505 	ANDROID_KABI_RESERVE(2);
506 };
507 
508 /**
509  * struct dma_buf_export_info - holds information needed to export a dma_buf
510  * @exp_name:	name of the exporter - useful for debugging.
511  * @owner:	pointer to exporter module - used for refcounting kernel module
512  * @ops:	Attach allocator-defined dma buf ops to the new buffer
513  * @size:	Size of the buffer
514  * @flags:	mode flags for the file
515  * @resv:	reservation-object, NULL to allocate default one
516  * @priv:	Attach private data of allocator to this buffer
517  *
518  * This structure holds the information required to export the buffer. Used
519  * with dma_buf_export() only.
520  */
521 struct dma_buf_export_info {
522 	const char *exp_name;
523 	struct module *owner;
524 	const struct dma_buf_ops *ops;
525 	size_t size;
526 	int flags;
527 	struct dma_resv *resv;
528 	void *priv;
529 
530 	ANDROID_KABI_RESERVE(1);
531 	ANDROID_KABI_RESERVE(2);
532 };
533 
534 /**
535  * DEFINE_DMA_BUF_EXPORT_INFO - helper macro for exporters
536  * @name: export-info name
537  *
538  * DEFINE_DMA_BUF_EXPORT_INFO macro defines the &struct dma_buf_export_info,
539  * zeroes it out and pre-populates exp_name in it.
540  */
541 #define DEFINE_DMA_BUF_EXPORT_INFO(name)	\
542 	struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
543 					 .owner = THIS_MODULE }
544 
545 /**
546  * get_dma_buf - convenience wrapper for get_file.
547  * @dmabuf:	[in]	pointer to dma_buf
548  *
549  * Increments the reference count on the dma-buf, needed in case of drivers
550  * that either need to create additional references to the dmabuf on the
551  * kernel side.  For example, an exporter that needs to keep a dmabuf ptr
552  * so that subsequent exports don't create a new dmabuf.
553  */
get_dma_buf(struct dma_buf * dmabuf)554 static inline void get_dma_buf(struct dma_buf *dmabuf)
555 {
556 	get_file(dmabuf->file);
557 }
558 
559 /**
560  * dma_buf_is_dynamic - check if a DMA-buf uses dynamic mappings.
561  * @dmabuf: the DMA-buf to check
562  *
563  * Returns true if a DMA-buf exporter wants to be called with the dma_resv
564  * locked for the map/unmap callbacks, false if it doesn't wants to be called
565  * with the lock held.
566  */
dma_buf_is_dynamic(struct dma_buf * dmabuf)567 static inline bool dma_buf_is_dynamic(struct dma_buf *dmabuf)
568 {
569 	return !!dmabuf->ops->pin;
570 }
571 
572 /**
573  * dma_buf_attachment_is_dynamic - check if a DMA-buf attachment uses dynamic
574  * mappinsg
575  * @attach: the DMA-buf attachment to check
576  *
577  * Returns true if a DMA-buf importer wants to call the map/unmap functions with
578  * the dma_resv lock held.
579  */
580 static inline bool
dma_buf_attachment_is_dynamic(struct dma_buf_attachment * attach)581 dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach)
582 {
583 	return !!attach->importer_ops;
584 }
585 
586 int get_each_dmabuf(int (*callback)(const struct dma_buf *dmabuf,
587 		    void *private), void *private);
588 int is_dma_buf_file(struct file *file);
589 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
590 					  struct device *dev);
591 struct dma_buf_attachment *
592 dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
593 		       const struct dma_buf_attach_ops *importer_ops,
594 		       void *importer_priv);
595 void dma_buf_detach(struct dma_buf *dmabuf,
596 		    struct dma_buf_attachment *attach);
597 int dma_buf_pin(struct dma_buf_attachment *attach);
598 void dma_buf_unpin(struct dma_buf_attachment *attach);
599 
600 struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);
601 
602 int dma_buf_fd(struct dma_buf *dmabuf, int flags);
603 struct dma_buf *dma_buf_get(int fd);
604 void dma_buf_put(struct dma_buf *dmabuf);
605 
606 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
607 					enum dma_data_direction);
608 void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
609 				enum dma_data_direction);
610 void dma_buf_move_notify(struct dma_buf *dma_buf);
611 int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
612 			     enum dma_data_direction dir);
613 int dma_buf_begin_cpu_access_partial(struct dma_buf *dma_buf,
614 				     enum dma_data_direction dir,
615 				     unsigned int offset, unsigned int len);
616 int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
617 			   enum dma_data_direction dir);
618 int dma_buf_end_cpu_access_partial(struct dma_buf *dma_buf,
619 				     enum dma_data_direction dir,
620 				     unsigned int offset, unsigned int len);
621 
622 int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
623 		 unsigned long);
624 void *dma_buf_vmap(struct dma_buf *);
625 void dma_buf_vunmap(struct dma_buf *, void *vaddr);
626 long dma_buf_set_name(struct dma_buf *dmabuf, const char *name);
627 int dma_buf_get_flags(struct dma_buf *dmabuf, unsigned long *flags);
628 int dma_buf_get_uuid(struct dma_buf *dmabuf, uuid_t *uuid);
629 
630 #endif /* __DMA_BUF_H__ */
631