[deliverable/linux.git] / drivers / media / v4l2-core / videobuf2-dma-sg.c

/*
 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <media/videobuf2-core.h>
#include <media/videobuf2-memops.h>
#include <media/videobuf2-dma-sg.h>

static int debug;
module_param(debug, int, 0644);

#define dprintk(level, fmt, arg...)					\
	do {								\
		if (debug >= level)					\
			printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);	\
	} while (0)

struct vb2_dma_sg_buf {
	void				*vaddr;
	struct page			**pages;
	int				write;
	int				offset;
	struct sg_table			sg_table;
	size_t				size;
	unsigned int			num_pages;
	atomic_t			refcount;
	struct vb2_vmarea_handler	handler;
	struct vm_area_struct		*vma;
};

static void vb2_dma_sg_put(void *buf_priv);

static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
		gfp_t gfp_flags)
{
	unsigned int last_page = 0;
	int size = buf->size;

	while (size > 0) {
		struct page *pages;
		int order;
		int i;

		order = get_order(size);
		/* Dont over allocate*/
		if ((PAGE_SIZE << order) > size)
			order--;

		pages = NULL;
		while (!pages) {
			pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
					__GFP_NOWARN | gfp_flags, order);
			if (pages)
				break;

			if (order == 0) {
				while (last_page--)
					__free_page(buf->pages[last_page]);
				return -ENOMEM;
			}
			order--;
		}

		split_page(pages, order);
		for (i = 0; i < (1 << order); i++)
			buf->pages[last_page++] = &pages[i];

		size -= PAGE_SIZE << order;
	}

	return 0;
}

static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
{
	struct vb2_dma_sg_buf *buf;
	int ret;
	int num_pages;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->vaddr = NULL;
	buf->write = 0;
	buf->offset = 0;
	buf->size = size;
	/* size is already page aligned */
	buf->num_pages = size >> PAGE_SHIFT;

	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
			     GFP_KERNEL);
	if (!buf->pages)
		goto fail_pages_array_alloc;

	ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
	if (ret)
		goto fail_pages_alloc;

	ret = sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
			buf->num_pages, 0, size, gfp_flags);
	if (ret)
		goto fail_table_alloc;

	buf->handler.refcount = &buf->refcount;
	buf->handler.put = vb2_dma_sg_put;
	buf->handler.arg = buf;

	atomic_inc(&buf->refcount);

	dprintk(1, "%s: Allocated buffer of %d pages\n",
		__func__, buf->num_pages);
	return buf;

fail_table_alloc:
	num_pages = buf->num_pages;
	while (num_pages--)
		__free_page(buf->pages[num_pages]);
fail_pages_alloc:
	kfree(buf->pages);
fail_pages_array_alloc:
	kfree(buf);
	return NULL;
}

static void vb2_dma_sg_put(void *buf_priv)
{
	struct vb2_dma_sg_buf *buf = buf_priv;
	int i = buf->num_pages;

	if (atomic_dec_and_test(&buf->refcount)) {
		dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
			buf->num_pages);
		if (buf->vaddr)
			vm_unmap_ram(buf->vaddr, buf->num_pages);
		sg_free_table(&buf->sg_table);
		while (--i >= 0)
			__free_page(buf->pages[i]);
		kfree(buf->pages);
		kfree(buf);
	}
}

static inline int vma_is_io(struct vm_area_struct *vma)
{
	return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
}

static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
				    unsigned long size, int write)
{
	struct vb2_dma_sg_buf *buf;
	unsigned long first, last;
	int num_pages_from_user;
	struct vm_area_struct *vma;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->vaddr = NULL;
	buf->write = write;
	buf->offset = vaddr & ~PAGE_MASK;
	buf->size = size;

	first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
	last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
	buf->num_pages = last - first + 1;

	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
			     GFP_KERNEL);
	if (!buf->pages)
		goto userptr_fail_alloc_pages;

	vma = find_vma(current->mm, vaddr);
	if (!vma) {
		dprintk(1, "no vma for address %lu\n", vaddr);
		goto userptr_fail_find_vma;
	}

	if (vma->vm_end < vaddr + size) {
		dprintk(1, "vma at %lu is too small for %lu bytes\n",
			vaddr, size);
		goto userptr_fail_find_vma;
	}

	buf->vma = vb2_get_vma(vma);
	if (!buf->vma) {
		dprintk(1, "failed to copy vma\n");
		goto userptr_fail_find_vma;
	}

	if (vma_is_io(buf->vma)) {
		for (num_pages_from_user = 0;
		     num_pages_from_user < buf->num_pages;
		     ++num_pages_from_user, vaddr += PAGE_SIZE) {
			unsigned long pfn;

			if (follow_pfn(vma, vaddr, &pfn)) {
				dprintk(1, "no page for address %lu\n", vaddr);
				break;
			}
			buf->pages[num_pages_from_user] = pfn_to_page(pfn);
		}
	} else
		num_pages_from_user = get_user_pages(current, current->mm,
					     vaddr & PAGE_MASK,
					     buf->num_pages,
					     write,
					     1, /* force */
					     buf->pages,
					     NULL);

	if (num_pages_from_user != buf->num_pages)
		goto userptr_fail_get_user_pages;

	if (sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
			buf->num_pages, buf->offset, size, 0))
		goto userptr_fail_alloc_table_from_pages;

	return buf;

userptr_fail_alloc_table_from_pages:
userptr_fail_get_user_pages:
	dprintk(1, "get_user_pages requested/got: %d/%d]\n",
		buf->num_pages, num_pages_from_user);
	if (!vma_is_io(buf->vma))
		while (--num_pages_from_user >= 0)
			put_page(buf->pages[num_pages_from_user]);
	vb2_put_vma(buf->vma);
userptr_fail_find_vma:
	kfree(buf->pages);
userptr_fail_alloc_pages:
	kfree(buf);
	return NULL;
}

/*
 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 *		 be used
 */
static void vb2_dma_sg_put_userptr(void *buf_priv)
{
	struct vb2_dma_sg_buf *buf = buf_priv;
	int i = buf->num_pages;

	dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
	       __func__, buf->num_pages);
	if (buf->vaddr)
		vm_unmap_ram(buf->vaddr, buf->num_pages);
	sg_free_table(&buf->sg_table);
	while (--i >= 0) {
		if (buf->write)
			set_page_dirty_lock(buf->pages[i]);
		if (!vma_is_io(buf->vma))
			put_page(buf->pages[i]);
	}
	kfree(buf->pages);
	vb2_put_vma(buf->vma);
	kfree(buf);
}

static void *vb2_dma_sg_vaddr(void *buf_priv)
{
	struct vb2_dma_sg_buf *buf = buf_priv;

	BUG_ON(!buf);

	if (!buf->vaddr)
		buf->vaddr = vm_map_ram(buf->pages,
					buf->num_pages,
					-1,
					PAGE_KERNEL);

	/* add offset in case userptr is not page-aligned */
	return buf->vaddr + buf->offset;
}

static unsigned int vb2_dma_sg_num_users(void *buf_priv)
{
	struct vb2_dma_sg_buf *buf = buf_priv;

	return atomic_read(&buf->refcount);
}

static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
{
	struct vb2_dma_sg_buf *buf = buf_priv;
	unsigned long uaddr = vma->vm_start;
	unsigned long usize = vma->vm_end - vma->vm_start;
	int i = 0;

	if (!buf) {
		printk(KERN_ERR "No memory to map\n");
		return -EINVAL;
	}

	do {
		int ret;

		ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
		if (ret) {
			printk(KERN_ERR "Remapping memory, error: %d\n", ret);
			return ret;
		}

		uaddr += PAGE_SIZE;
		usize -= PAGE_SIZE;
	} while (usize > 0);


	/*
	 * Use common vm_area operations to track buffer refcount.
	 */
	vma->vm_private_data	= &buf->handler;
	vma->vm_ops		= &vb2_common_vm_ops;

	vma->vm_ops->open(vma);

	return 0;
}

static void *vb2_dma_sg_cookie(void *buf_priv)
{
	struct vb2_dma_sg_buf *buf = buf_priv;

	return &buf->sg_table;
}

const struct vb2_mem_ops vb2_dma_sg_memops = {
	.alloc		= vb2_dma_sg_alloc,
	.put		= vb2_dma_sg_put,
	.get_userptr	= vb2_dma_sg_get_userptr,
	.put_userptr	= vb2_dma_sg_put_userptr,
	.vaddr		= vb2_dma_sg_vaddr,
	.mmap		= vb2_dma_sg_mmap,
	.num_users	= vb2_dma_sg_num_users,
	.cookie		= vb2_dma_sg_cookie,
};
EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);

MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
MODULE_AUTHOR("Andrzej Pietrasiewicz");
MODULE_LICENSE("GPL");
Commit	Line	Data
5ba3f757 AP	1	/*
	2	* videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
	3	*
	4	* Copyright (C) 2010 Samsung Electronics
	5	*
	6	* Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/mm.h>
	15	#include <linux/scatterlist.h>
	16	#include <linux/sched.h>
	17	#include <linux/slab.h>
	18	#include <linux/vmalloc.h>
	19
	20	#include <media/videobuf2-core.h>
	21	#include <media/videobuf2-memops.h>
	22	#include <media/videobuf2-dma-sg.h>
	23
ffdc78ef HV	24	static int debug;
	25	module_param(debug, int, 0644);
	26
	27	#define dprintk(level, fmt, arg...) \
	28	do { \
	29	if (debug >= level) \
	30	printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
	31	} while (0)
	32
5ba3f757 AP	33	struct vb2_dma_sg_buf {
	34	void *vaddr;
	35	struct page **pages;
	36	int write;
	37	int offset;
22301247 RR	38	struct sg_table sg_table;
	39	size_t size;
	40	unsigned int num_pages;
5ba3f757 AP	41	atomic_t refcount;
5ba3f757 AP	42	struct vb2_vmarea_handler handler;
50ac952d	43	struct vm_area_struct *vma;
5ba3f757 AP	44	};
	45
	46	static void vb2_dma_sg_put(void *buf_priv);
	47
df237281 RR	48	static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
	49	gfp_t gfp_flags)
	50	{
	51	unsigned int last_page = 0;
22301247	52	int size = buf->size;
df237281 RR	53
	54	while (size > 0) {
	55	struct page *pages;
	56	int order;
	57	int i;
	58
	59	order = get_order(size);
	60	/* Dont over allocate*/
	61	if ((PAGE_SIZE << order) > size)
	62	order--;
	63
	64	pages = NULL;
	65	while (!pages) {
	66	pages = alloc_pages(GFP_KERNEL \| __GFP_ZERO \|
	67	__GFP_NOWARN \| gfp_flags, order);
	68	if (pages)
	69	break;
	70
	71	if (order == 0) {
	72	while (last_page--)
	73	__free_page(buf->pages[last_page]);
	74	return -ENOMEM;
	75	}
	76	order--;
	77	}
	78
	79	split_page(pages, order);
22301247 RR	80	for (i = 0; i < (1 << order); i++)
22301247 RR	81	buf->pages[last_page++] = &pages[i];
df237281 RR	82
	83	size -= PAGE_SIZE << order;
	84	}
	85
	86	return 0;
	87	}
	88
b6ba2057	89	static void vb2_dma_sg_alloc(void alloc_ctx, unsigned long size, gfp_t gfp_flags)
5ba3f757 AP	90	{
5ba3f757 AP	91	struct vb2_dma_sg_buf *buf;
df237281	92	int ret;
22301247	93	int num_pages;
5ba3f757 AP	94
	95	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	96	if (!buf)
	97	return NULL;
	98
	99	buf->vaddr = NULL;
	100	buf->write = 0;
	101	buf->offset = 0;
22301247	102	buf->size = size;
7f841459	103	/* size is already page aligned */
22301247	104	buf->num_pages = size >> PAGE_SHIFT;
5ba3f757	105
22301247	106	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
5ba3f757 AP	107	GFP_KERNEL);
	108	if (!buf->pages)
	109	goto fail_pages_array_alloc;
	110
df237281 RR	111	ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
	112	if (ret)
	113	goto fail_pages_alloc;
5ba3f757	114
22301247 RR	115	ret = sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
	116	buf->num_pages, 0, size, gfp_flags);
	117	if (ret)
	118	goto fail_table_alloc;
	119
5ba3f757 AP	120	buf->handler.refcount = &buf->refcount;
	121	buf->handler.put = vb2_dma_sg_put;
	122	buf->handler.arg = buf;
	123
	124	atomic_inc(&buf->refcount);
	125
ffdc78ef	126	dprintk(1, "%s: Allocated buffer of %d pages\n",
22301247	127	__func__, buf->num_pages);
5ba3f757 AP	128	return buf;
5ba3f757 AP	129
22301247 RR	130	fail_table_alloc:
	131	num_pages = buf->num_pages;
	132	while (num_pages--)
	133	__free_page(buf->pages[num_pages]);
5ba3f757	134	fail_pages_alloc:
a9bb36aa	135	kfree(buf->pages);
5ba3f757	136	fail_pages_array_alloc:
5ba3f757 AP	137	kfree(buf);
	138	return NULL;
	139	}
	140
	141	static void vb2_dma_sg_put(void *buf_priv)
	142	{
	143	struct vb2_dma_sg_buf *buf = buf_priv;
22301247	144	int i = buf->num_pages;
5ba3f757 AP	145
5ba3f757 AP	146	if (atomic_dec_and_test(&buf->refcount)) {
ffdc78ef	147	dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
22301247	148	buf->num_pages);
5ba3f757	149	if (buf->vaddr)
22301247 RR	150	vm_unmap_ram(buf->vaddr, buf->num_pages);
22301247 RR	151	sg_free_table(&buf->sg_table);
5ba3f757 AP	152	while (--i >= 0)
	153	__free_page(buf->pages[i]);
	154	kfree(buf->pages);
	155	kfree(buf);
	156	}
	157	}
	158
50ac952d RR	159	static inline int vma_is_io(struct vm_area_struct *vma)
	160	{
	161	return !!(vma->vm_flags & (VM_IO \| VM_PFNMAP));
	162	}
	163
5ba3f757 AP	164	static void vb2_dma_sg_get_userptr(void alloc_ctx, unsigned long vaddr,
	165	unsigned long size, int write)
	166	{
	167	struct vb2_dma_sg_buf *buf;
	168	unsigned long first, last;
22301247	169	int num_pages_from_user;
50ac952d	170	struct vm_area_struct *vma;
5ba3f757 AP	171
	172	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	173	if (!buf)
	174	return NULL;
	175
	176	buf->vaddr = NULL;
	177	buf->write = write;
	178	buf->offset = vaddr & ~PAGE_MASK;
22301247	179	buf->size = size;
5ba3f757 AP	180
	181	first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
	182	last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
22301247	183	buf->num_pages = last - first + 1;
5ba3f757	184
22301247	185	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
5ba3f757 AP	186	GFP_KERNEL);
5ba3f757 AP	187	if (!buf->pages)
64c832a4	188	goto userptr_fail_alloc_pages;
5ba3f757	189
50ac952d RR	190	vma = find_vma(current->mm, vaddr);
	191	if (!vma) {
	192	dprintk(1, "no vma for address %lu\n", vaddr);
	193	goto userptr_fail_find_vma;
	194	}
	195
	196	if (vma->vm_end < vaddr + size) {
	197	dprintk(1, "vma at %lu is too small for %lu bytes\n",
	198	vaddr, size);
	199	goto userptr_fail_find_vma;
	200	}
	201
	202	buf->vma = vb2_get_vma(vma);
	203	if (!buf->vma) {
	204	dprintk(1, "failed to copy vma\n");
	205	goto userptr_fail_find_vma;
	206	}
	207
	208	if (vma_is_io(buf->vma)) {
	209	for (num_pages_from_user = 0;
	210	num_pages_from_user < buf->num_pages;
	211	++num_pages_from_user, vaddr += PAGE_SIZE) {
	212	unsigned long pfn;
	213
227ae227	214	if (follow_pfn(vma, vaddr, &pfn)) {
50ac952d RR	215	dprintk(1, "no page for address %lu\n", vaddr);
	216	break;
	217	}
	218	buf->pages[num_pages_from_user] = pfn_to_page(pfn);
	219	}
	220	} else
	221	num_pages_from_user = get_user_pages(current, current->mm,
5ba3f757	222	vaddr & PAGE_MASK,
22301247	223	buf->num_pages,
5ba3f757 AP	224	write,
	225	1, /* force */
	226	buf->pages,
	227	NULL);
b037c0fd	228
22301247	229	if (num_pages_from_user != buf->num_pages)
5ba3f757 AP	230	goto userptr_fail_get_user_pages;
5ba3f757 AP	231
22301247 RR	232	if (sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
	233	buf->num_pages, buf->offset, size, 0))
	234	goto userptr_fail_alloc_table_from_pages;
	235
5ba3f757 AP	236	return buf;
5ba3f757 AP	237
22301247	238	userptr_fail_alloc_table_from_pages:
5ba3f757	239	userptr_fail_get_user_pages:
ffdc78ef	240	dprintk(1, "get_user_pages requested/got: %d/%d]\n",
202dfbdc	241	buf->num_pages, num_pages_from_user);
50ac952d RR	242	if (!vma_is_io(buf->vma))
	243	while (--num_pages_from_user >= 0)
	244	put_page(buf->pages[num_pages_from_user]);
	245	vb2_put_vma(buf->vma);
	246	userptr_fail_find_vma:
a9bb36aa	247	kfree(buf->pages);
64c832a4	248	userptr_fail_alloc_pages:
5ba3f757 AP	249	kfree(buf);
	250	return NULL;
	251	}
	252
	253	/*
	254	* @put_userptr: inform the allocator that a USERPTR buffer will no longer
	255	* be used
	256	*/
	257	static void vb2_dma_sg_put_userptr(void *buf_priv)
	258	{
	259	struct vb2_dma_sg_buf *buf = buf_priv;
22301247	260	int i = buf->num_pages;
5ba3f757	261
ffdc78ef	262	dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
22301247	263	__func__, buf->num_pages);
5ba3f757	264	if (buf->vaddr)
22301247 RR	265	vm_unmap_ram(buf->vaddr, buf->num_pages);
22301247 RR	266	sg_free_table(&buf->sg_table);
5ba3f757 AP	267	while (--i >= 0) {
	268	if (buf->write)
	269	set_page_dirty_lock(buf->pages[i]);
50ac952d RR	270	if (!vma_is_io(buf->vma))
50ac952d RR	271	put_page(buf->pages[i]);
5ba3f757	272	}
5ba3f757	273	kfree(buf->pages);
50ac952d	274	vb2_put_vma(buf->vma);
5ba3f757 AP	275	kfree(buf);
	276	}
	277
	278	static void vb2_dma_sg_vaddr(void buf_priv)
	279	{
	280	struct vb2_dma_sg_buf *buf = buf_priv;
	281
	282	BUG_ON(!buf);
	283
	284	if (!buf->vaddr)
	285	buf->vaddr = vm_map_ram(buf->pages,
22301247	286	buf->num_pages,
5ba3f757 AP	287	-1,
	288	PAGE_KERNEL);
	289
	290	/* add offset in case userptr is not page-aligned */
	291	return buf->vaddr + buf->offset;
	292	}
	293
	294	static unsigned int vb2_dma_sg_num_users(void *buf_priv)
	295	{
	296	struct vb2_dma_sg_buf *buf = buf_priv;
	297
	298	return atomic_read(&buf->refcount);
	299	}
	300
	301	static int vb2_dma_sg_mmap(void buf_priv, struct vm_area_struct vma)
	302	{
	303	struct vb2_dma_sg_buf *buf = buf_priv;
	304	unsigned long uaddr = vma->vm_start;
	305	unsigned long usize = vma->vm_end - vma->vm_start;
	306	int i = 0;
	307
	308	if (!buf) {
	309	printk(KERN_ERR "No memory to map\n");
	310	return -EINVAL;
	311	}
	312
	313	do {
	314	int ret;
	315
	316	ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
	317	if (ret) {
	318	printk(KERN_ERR "Remapping memory, error: %d\n", ret);
	319	return ret;
	320	}
	321
	322	uaddr += PAGE_SIZE;
	323	usize -= PAGE_SIZE;
	324	} while (usize > 0);
	325
	326
	327	/*
	328	* Use common vm_area operations to track buffer refcount.
	329	*/
	330	vma->vm_private_data = &buf->handler;
	331	vma->vm_ops = &vb2_common_vm_ops;
	332
	333	vma->vm_ops->open(vma);
	334
	335	return 0;
	336	}
	337
	338	static void vb2_dma_sg_cookie(void buf_priv)
	339	{
	340	struct vb2_dma_sg_buf *buf = buf_priv;
	341
22301247	342	return &buf->sg_table;
5ba3f757 AP	343	}
	344
	345	const struct vb2_mem_ops vb2_dma_sg_memops = {
	346	.alloc = vb2_dma_sg_alloc,
	347	.put = vb2_dma_sg_put,
	348	.get_userptr = vb2_dma_sg_get_userptr,
	349	.put_userptr = vb2_dma_sg_put_userptr,
	350	.vaddr = vb2_dma_sg_vaddr,
	351	.mmap = vb2_dma_sg_mmap,
	352	.num_users = vb2_dma_sg_num_users,
	353	.cookie = vb2_dma_sg_cookie,
	354	};
	355	EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
	356
	357	MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
	358	MODULE_AUTHOR("Andrzej Pietrasiewicz");
	359	MODULE_LICENSE("GPL");