cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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dma-buf.h (21321B)


      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/iosys-map.h>
     17#include <linux/file.h>
     18#include <linux/err.h>
     19#include <linux/scatterlist.h>
     20#include <linux/list.h>
     21#include <linux/dma-mapping.h>
     22#include <linux/fs.h>
     23#include <linux/dma-fence.h>
     24#include <linux/wait.h>
     25
     26struct device;
     27struct dma_buf;
     28struct 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 */
     36struct 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 fulfills 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. Ideally, the exporter should
     90	 * pin the buffer so that it is generally accessible by all
     91	 * devices.
     92	 *
     93	 * This is called with the &dmabuf.resv object locked and is mutual
     94	 * exclusive with @cache_sgt_mapping.
     95	 *
     96	 * This is called automatically for non-dynamic importers from
     97	 * dma_buf_attach().
     98	 *
     99	 * Note that similar to non-dynamic exporters in their @map_dma_buf
    100	 * callback the driver must guarantee that the memory is available for
    101	 * use and cleared of any old data by the time this function returns.
    102	 * Drivers which pipeline their buffer moves internally must wait for
    103	 * all moves and clears to complete.
    104	 *
    105	 * Returns:
    106	 *
    107	 * 0 on success, negative error code on failure.
    108	 */
    109	int (*pin)(struct dma_buf_attachment *attach);
    110
    111	/**
    112	 * @unpin:
    113	 *
    114	 * This is called by dma_buf_unpin() and lets the exporter know that the
    115	 * DMA-buf can be moved again.
    116	 *
    117	 * This is called with the dmabuf->resv object locked and is mutual
    118	 * exclusive with @cache_sgt_mapping.
    119	 *
    120	 * This callback is optional.
    121	 */
    122	void (*unpin)(struct dma_buf_attachment *attach);
    123
    124	/**
    125	 * @map_dma_buf:
    126	 *
    127	 * This is called by dma_buf_map_attachment() and is used to map a
    128	 * shared &dma_buf into device address space, and it is mandatory. It
    129	 * can only be called if @attach has been called successfully.
    130	 *
    131	 * This call may sleep, e.g. when the backing storage first needs to be
    132	 * allocated, or moved to a location suitable for all currently attached
    133	 * devices.
    134	 *
    135	 * Note that any specific buffer attributes required for this function
    136	 * should get added to device_dma_parameters accessible via
    137	 * &device.dma_params from the &dma_buf_attachment. The @attach callback
    138	 * should also check these constraints.
    139	 *
    140	 * If this is being called for the first time, the exporter can now
    141	 * choose to scan through the list of attachments for this buffer,
    142	 * collate the requirements of the attached devices, and choose an
    143	 * appropriate backing storage for the buffer.
    144	 *
    145	 * Based on enum dma_data_direction, it might be possible to have
    146	 * multiple users accessing at the same time (for reading, maybe), or
    147	 * any other kind of sharing that the exporter might wish to make
    148	 * available to buffer-users.
    149	 *
    150	 * This is always called with the dmabuf->resv object locked when
    151	 * the dynamic_mapping flag is true.
    152	 *
    153	 * Note that for non-dynamic exporters the driver must guarantee that
    154	 * that the memory is available for use and cleared of any old data by
    155	 * the time this function returns.  Drivers which pipeline their buffer
    156	 * moves internally must wait for all moves and clears to complete.
    157	 * Dynamic exporters do not need to follow this rule: For non-dynamic
    158	 * importers the buffer is already pinned through @pin, which has the
    159	 * same requirements. Dynamic importers otoh are required to obey the
    160	 * dma_resv fences.
    161	 *
    162	 * Returns:
    163	 *
    164	 * A &sg_table scatter list of the backing storage of the DMA buffer,
    165	 * already mapped into the device address space of the &device attached
    166	 * with the provided &dma_buf_attachment. The addresses and lengths in
    167	 * the scatter list are PAGE_SIZE aligned.
    168	 *
    169	 * On failure, returns a negative error value wrapped into a pointer.
    170	 * May also return -EINTR when a signal was received while being
    171	 * blocked.
    172	 *
    173	 * Note that exporters should not try to cache the scatter list, or
    174	 * return the same one for multiple calls. Caching is done either by the
    175	 * DMA-BUF code (for non-dynamic importers) or the importer. Ownership
    176	 * of the scatter list is transferred to the caller, and returned by
    177	 * @unmap_dma_buf.
    178	 */
    179	struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
    180					 enum dma_data_direction);
    181	/**
    182	 * @unmap_dma_buf:
    183	 *
    184	 * This is called by dma_buf_unmap_attachment() and should unmap and
    185	 * release the &sg_table allocated in @map_dma_buf, and it is mandatory.
    186	 * For static dma_buf handling this might also unpin the backing
    187	 * storage if this is the last mapping of the DMA buffer.
    188	 */
    189	void (*unmap_dma_buf)(struct dma_buf_attachment *,
    190			      struct sg_table *,
    191			      enum dma_data_direction);
    192
    193	/* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
    194	 * if the call would block.
    195	 */
    196
    197	/**
    198	 * @release:
    199	 *
    200	 * Called after the last dma_buf_put to release the &dma_buf, and
    201	 * mandatory.
    202	 */
    203	void (*release)(struct dma_buf *);
    204
    205	/**
    206	 * @begin_cpu_access:
    207	 *
    208	 * This is called from dma_buf_begin_cpu_access() and allows the
    209	 * exporter to ensure that the memory is actually coherent for cpu
    210	 * access. The exporter also needs to ensure that cpu access is coherent
    211	 * for the access direction. The direction can be used by the exporter
    212	 * to optimize the cache flushing, i.e. access with a different
    213	 * direction (read instead of write) might return stale or even bogus
    214	 * data (e.g. when the exporter needs to copy the data to temporary
    215	 * storage).
    216	 *
    217	 * Note that this is both called through the DMA_BUF_IOCTL_SYNC IOCTL
    218	 * command for userspace mappings established through @mmap, and also
    219	 * for kernel mappings established with @vmap.
    220	 *
    221	 * This callback is optional.
    222	 *
    223	 * Returns:
    224	 *
    225	 * 0 on success or a negative error code on failure. This can for
    226	 * example fail when the backing storage can't be allocated. Can also
    227	 * return -ERESTARTSYS or -EINTR when the call has been interrupted and
    228	 * needs to be restarted.
    229	 */
    230	int (*begin_cpu_access)(struct dma_buf *, enum dma_data_direction);
    231
    232	/**
    233	 * @end_cpu_access:
    234	 *
    235	 * This is called from dma_buf_end_cpu_access() when the importer is
    236	 * done accessing the CPU. The exporter can use this to flush caches and
    237	 * undo anything else done in @begin_cpu_access.
    238	 *
    239	 * This callback is optional.
    240	 *
    241	 * Returns:
    242	 *
    243	 * 0 on success or a negative error code on failure. Can return
    244	 * -ERESTARTSYS or -EINTR when the call has been interrupted and needs
    245	 * to be restarted.
    246	 */
    247	int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
    248
    249	/**
    250	 * @mmap:
    251	 *
    252	 * This callback is used by the dma_buf_mmap() function
    253	 *
    254	 * Note that the mapping needs to be incoherent, userspace is expected
    255	 * to bracket CPU access using the DMA_BUF_IOCTL_SYNC interface.
    256	 *
    257	 * Because dma-buf buffers have invariant size over their lifetime, the
    258	 * dma-buf core checks whether a vma is too large and rejects such
    259	 * mappings. The exporter hence does not need to duplicate this check.
    260	 * Drivers do not need to check this themselves.
    261	 *
    262	 * If an exporter needs to manually flush caches and hence needs to fake
    263	 * coherency for mmap support, it needs to be able to zap all the ptes
    264	 * pointing at the backing storage. Now linux mm needs a struct
    265	 * address_space associated with the struct file stored in vma->vm_file
    266	 * to do that with the function unmap_mapping_range. But the dma_buf
    267	 * framework only backs every dma_buf fd with the anon_file struct file,
    268	 * i.e. all dma_bufs share the same file.
    269	 *
    270	 * Hence exporters need to setup their own file (and address_space)
    271	 * association by setting vma->vm_file and adjusting vma->vm_pgoff in
    272	 * the dma_buf mmap callback. In the specific case of a gem driver the
    273	 * exporter could use the shmem file already provided by gem (and set
    274	 * vm_pgoff = 0). Exporters can then zap ptes by unmapping the
    275	 * corresponding range of the struct address_space associated with their
    276	 * own file.
    277	 *
    278	 * This callback is optional.
    279	 *
    280	 * Returns:
    281	 *
    282	 * 0 on success or a negative error code on failure.
    283	 */
    284	int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
    285
    286	int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map);
    287	void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map);
    288};
    289
    290/**
    291 * struct dma_buf - shared buffer object
    292 *
    293 * This represents a shared buffer, created by calling dma_buf_export(). The
    294 * userspace representation is a normal file descriptor, which can be created by
    295 * calling dma_buf_fd().
    296 *
    297 * Shared dma buffers are reference counted using dma_buf_put() and
    298 * get_dma_buf().
    299 *
    300 * Device DMA access is handled by the separate &struct dma_buf_attachment.
    301 */
    302struct dma_buf {
    303	/**
    304	 * @size:
    305	 *
    306	 * Size of the buffer; invariant over the lifetime of the buffer.
    307	 */
    308	size_t size;
    309
    310	/**
    311	 * @file:
    312	 *
    313	 * File pointer used for sharing buffers across, and for refcounting.
    314	 * See dma_buf_get() and dma_buf_put().
    315	 */
    316	struct file *file;
    317
    318	/**
    319	 * @attachments:
    320	 *
    321	 * List of dma_buf_attachment that denotes all devices attached,
    322	 * protected by &dma_resv lock @resv.
    323	 */
    324	struct list_head attachments;
    325
    326	/** @ops: dma_buf_ops associated with this buffer object. */
    327	const struct dma_buf_ops *ops;
    328
    329	/**
    330	 * @lock:
    331	 *
    332	 * Used internally to serialize list manipulation, attach/detach and
    333	 * vmap/unmap. Note that in many cases this is superseeded by
    334	 * dma_resv_lock() on @resv.
    335	 */
    336	struct mutex lock;
    337
    338	/**
    339	 * @vmapping_counter:
    340	 *
    341	 * Used internally to refcnt the vmaps returned by dma_buf_vmap().
    342	 * Protected by @lock.
    343	 */
    344	unsigned vmapping_counter;
    345
    346	/**
    347	 * @vmap_ptr:
    348	 * The current vmap ptr if @vmapping_counter > 0. Protected by @lock.
    349	 */
    350	struct iosys_map vmap_ptr;
    351
    352	/**
    353	 * @exp_name:
    354	 *
    355	 * Name of the exporter; useful for debugging. See the
    356	 * DMA_BUF_SET_NAME IOCTL.
    357	 */
    358	const char *exp_name;
    359
    360	/**
    361	 * @name:
    362	 *
    363	 * Userspace-provided name; useful for accounting and debugging,
    364	 * protected by dma_resv_lock() on @resv and @name_lock for read access.
    365	 */
    366	const char *name;
    367
    368	/** @name_lock: Spinlock to protect name acces for read access. */
    369	spinlock_t name_lock;
    370
    371	/**
    372	 * @owner:
    373	 *
    374	 * Pointer to exporter module; used for refcounting when exporter is a
    375	 * kernel module.
    376	 */
    377	struct module *owner;
    378
    379	/** @list_node: node for dma_buf accounting and debugging. */
    380	struct list_head list_node;
    381
    382	/** @priv: exporter specific private data for this buffer object. */
    383	void *priv;
    384
    385	/**
    386	 * @resv:
    387	 *
    388	 * Reservation object linked to this dma-buf.
    389	 *
    390	 * IMPLICIT SYNCHRONIZATION RULES:
    391	 *
    392	 * Drivers which support implicit synchronization of buffer access as
    393	 * e.g. exposed in `Implicit Fence Poll Support`_ must follow the
    394	 * below rules.
    395	 *
    396	 * - Drivers must add a read fence through dma_resv_add_fence() with the
    397	 *   DMA_RESV_USAGE_READ flag for anything the userspace API considers a
    398	 *   read access. This highly depends upon the API and window system.
    399	 *
    400	 * - Similarly drivers must add a write fence through
    401	 *   dma_resv_add_fence() with the DMA_RESV_USAGE_WRITE flag for
    402	 *   anything the userspace API considers write access.
    403	 *
    404	 * - Drivers may just always add a write fence, since that only
    405	 *   causes unecessarily synchronization, but no correctness issues.
    406	 *
    407	 * - Some drivers only expose a synchronous userspace API with no
    408	 *   pipelining across drivers. These do not set any fences for their
    409	 *   access. An example here is v4l.
    410	 *
    411	 * - Driver should use dma_resv_usage_rw() when retrieving fences as
    412	 *   dependency for implicit synchronization.
    413	 *
    414	 * DYNAMIC IMPORTER RULES:
    415	 *
    416	 * Dynamic importers, see dma_buf_attachment_is_dynamic(), have
    417	 * additional constraints on how they set up fences:
    418	 *
    419	 * - Dynamic importers must obey the write fences and wait for them to
    420	 *   signal before allowing access to the buffer's underlying storage
    421	 *   through the device.
    422	 *
    423	 * - Dynamic importers should set fences for any access that they can't
    424	 *   disable immediately from their &dma_buf_attach_ops.move_notify
    425	 *   callback.
    426	 *
    427	 * IMPORTANT:
    428	 *
    429	 * All drivers and memory management related functions must obey the
    430	 * struct dma_resv rules, specifically the rules for updating and
    431	 * obeying fences. See enum dma_resv_usage for further descriptions.
    432	 */
    433	struct dma_resv *resv;
    434
    435	/** @poll: for userspace poll support */
    436	wait_queue_head_t poll;
    437
    438	/** @cb_in: for userspace poll support */
    439	/** @cb_out: for userspace poll support */
    440	struct dma_buf_poll_cb_t {
    441		struct dma_fence_cb cb;
    442		wait_queue_head_t *poll;
    443
    444		__poll_t active;
    445	} cb_in, cb_out;
    446#ifdef CONFIG_DMABUF_SYSFS_STATS
    447	/**
    448	 * @sysfs_entry:
    449	 *
    450	 * For exposing information about this buffer in sysfs. See also
    451	 * `DMA-BUF statistics`_ for the uapi this enables.
    452	 */
    453	struct dma_buf_sysfs_entry {
    454		struct kobject kobj;
    455		struct dma_buf *dmabuf;
    456	} *sysfs_entry;
    457#endif
    458};
    459
    460/**
    461 * struct dma_buf_attach_ops - importer operations for an attachment
    462 *
    463 * Attachment operations implemented by the importer.
    464 */
    465struct dma_buf_attach_ops {
    466	/**
    467	 * @allow_peer2peer:
    468	 *
    469	 * If this is set to true the importer must be able to handle peer
    470	 * resources without struct pages.
    471	 */
    472	bool allow_peer2peer;
    473
    474	/**
    475	 * @move_notify: [optional] notification that the DMA-buf is moving
    476	 *
    477	 * If this callback is provided the framework can avoid pinning the
    478	 * backing store while mappings exists.
    479	 *
    480	 * This callback is called with the lock of the reservation object
    481	 * associated with the dma_buf held and the mapping function must be
    482	 * called with this lock held as well. This makes sure that no mapping
    483	 * is created concurrently with an ongoing move operation.
    484	 *
    485	 * Mappings stay valid and are not directly affected by this callback.
    486	 * But the DMA-buf can now be in a different physical location, so all
    487	 * mappings should be destroyed and re-created as soon as possible.
    488	 *
    489	 * New mappings can be created after this callback returns, and will
    490	 * point to the new location of the DMA-buf.
    491	 */
    492	void (*move_notify)(struct dma_buf_attachment *attach);
    493};
    494
    495/**
    496 * struct dma_buf_attachment - holds device-buffer attachment data
    497 * @dmabuf: buffer for this attachment.
    498 * @dev: device attached to the buffer.
    499 * @node: list of dma_buf_attachment, protected by dma_resv lock of the dmabuf.
    500 * @sgt: cached mapping.
    501 * @dir: direction of cached mapping.
    502 * @peer2peer: true if the importer can handle peer resources without pages.
    503 * @priv: exporter specific attachment data.
    504 * @importer_ops: importer operations for this attachment, if provided
    505 * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held.
    506 * @importer_priv: importer specific attachment data.
    507 *
    508 * This structure holds the attachment information between the dma_buf buffer
    509 * and its user device(s). The list contains one attachment struct per device
    510 * attached to the buffer.
    511 *
    512 * An attachment is created by calling dma_buf_attach(), and released again by
    513 * calling dma_buf_detach(). The DMA mapping itself needed to initiate a
    514 * transfer is created by dma_buf_map_attachment() and freed again by calling
    515 * dma_buf_unmap_attachment().
    516 */
    517struct dma_buf_attachment {
    518	struct dma_buf *dmabuf;
    519	struct device *dev;
    520	struct list_head node;
    521	struct sg_table *sgt;
    522	enum dma_data_direction dir;
    523	bool peer2peer;
    524	const struct dma_buf_attach_ops *importer_ops;
    525	void *importer_priv;
    526	void *priv;
    527};
    528
    529/**
    530 * struct dma_buf_export_info - holds information needed to export a dma_buf
    531 * @exp_name:	name of the exporter - useful for debugging.
    532 * @owner:	pointer to exporter module - used for refcounting kernel module
    533 * @ops:	Attach allocator-defined dma buf ops to the new buffer
    534 * @size:	Size of the buffer - invariant over the lifetime of the buffer
    535 * @flags:	mode flags for the file
    536 * @resv:	reservation-object, NULL to allocate default one
    537 * @priv:	Attach private data of allocator to this buffer
    538 *
    539 * This structure holds the information required to export the buffer. Used
    540 * with dma_buf_export() only.
    541 */
    542struct dma_buf_export_info {
    543	const char *exp_name;
    544	struct module *owner;
    545	const struct dma_buf_ops *ops;
    546	size_t size;
    547	int flags;
    548	struct dma_resv *resv;
    549	void *priv;
    550};
    551
    552/**
    553 * DEFINE_DMA_BUF_EXPORT_INFO - helper macro for exporters
    554 * @name: export-info name
    555 *
    556 * DEFINE_DMA_BUF_EXPORT_INFO macro defines the &struct dma_buf_export_info,
    557 * zeroes it out and pre-populates exp_name in it.
    558 */
    559#define DEFINE_DMA_BUF_EXPORT_INFO(name)	\
    560	struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
    561					 .owner = THIS_MODULE }
    562
    563/**
    564 * get_dma_buf - convenience wrapper for get_file.
    565 * @dmabuf:	[in]	pointer to dma_buf
    566 *
    567 * Increments the reference count on the dma-buf, needed in case of drivers
    568 * that either need to create additional references to the dmabuf on the
    569 * kernel side.  For example, an exporter that needs to keep a dmabuf ptr
    570 * so that subsequent exports don't create a new dmabuf.
    571 */
    572static inline void get_dma_buf(struct dma_buf *dmabuf)
    573{
    574	get_file(dmabuf->file);
    575}
    576
    577/**
    578 * dma_buf_is_dynamic - check if a DMA-buf uses dynamic mappings.
    579 * @dmabuf: the DMA-buf to check
    580 *
    581 * Returns true if a DMA-buf exporter wants to be called with the dma_resv
    582 * locked for the map/unmap callbacks, false if it doesn't wants to be called
    583 * with the lock held.
    584 */
    585static inline bool dma_buf_is_dynamic(struct dma_buf *dmabuf)
    586{
    587	return !!dmabuf->ops->pin;
    588}
    589
    590/**
    591 * dma_buf_attachment_is_dynamic - check if a DMA-buf attachment uses dynamic
    592 * mappings
    593 * @attach: the DMA-buf attachment to check
    594 *
    595 * Returns true if a DMA-buf importer wants to call the map/unmap functions with
    596 * the dma_resv lock held.
    597 */
    598static inline bool
    599dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach)
    600{
    601	return !!attach->importer_ops;
    602}
    603
    604struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
    605					  struct device *dev);
    606struct dma_buf_attachment *
    607dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
    608		       const struct dma_buf_attach_ops *importer_ops,
    609		       void *importer_priv);
    610void dma_buf_detach(struct dma_buf *dmabuf,
    611		    struct dma_buf_attachment *attach);
    612int dma_buf_pin(struct dma_buf_attachment *attach);
    613void dma_buf_unpin(struct dma_buf_attachment *attach);
    614
    615struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);
    616
    617int dma_buf_fd(struct dma_buf *dmabuf, int flags);
    618struct dma_buf *dma_buf_get(int fd);
    619void dma_buf_put(struct dma_buf *dmabuf);
    620
    621struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
    622					enum dma_data_direction);
    623void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
    624				enum dma_data_direction);
    625void dma_buf_move_notify(struct dma_buf *dma_buf);
    626int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
    627			     enum dma_data_direction dir);
    628int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
    629			   enum dma_data_direction dir);
    630
    631int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
    632		 unsigned long);
    633int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map);
    634void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map);
    635#endif /* __DMA_BUF_H__ */