[mirror_ubuntu-eoan-kernel.git] / include / linux / scatterlist.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCATTERLIST_H
#define _LINUX_SCATTERLIST_H

#include <linux/string.h>
#include <linux/types.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <asm/io.h>

struct scatterlist {
	unsigned long	page_link;
	unsigned int	offset;
	unsigned int	length;
	dma_addr_t	dma_address;
#ifdef CONFIG_NEED_SG_DMA_LENGTH
	unsigned int	dma_length;
#endif
};

/*
 * Since the above length field is an unsigned int, below we define the maximum
 * length in bytes that can be stored in one scatterlist entry.
 */
#define SCATTERLIST_MAX_SEGMENT (UINT_MAX & PAGE_MASK)

/*
 * These macros should be used after a dma_map_sg call has been done
 * to get bus addresses of each of the SG entries and their lengths.
 * You should only work with the number of sg entries dma_map_sg
 * returns, or alternatively stop on the first sg_dma_len(sg) which
 * is 0.
 */
#define sg_dma_address(sg)	((sg)->dma_address)

#ifdef CONFIG_NEED_SG_DMA_LENGTH
#define sg_dma_len(sg)		((sg)->dma_length)
#else
#define sg_dma_len(sg)		((sg)->length)
#endif

struct sg_table {
	struct scatterlist *sgl;	/* the list */
	unsigned int nents;		/* number of mapped entries */
	unsigned int orig_nents;	/* original size of list */
};

/*
 * Notes on SG table design.
 *
 * We use the unsigned long page_link field in the scatterlist struct to place
 * the page pointer AND encode information about the sg table as well. The two
 * lower bits are reserved for this information.
 *
 * If bit 0 is set, then the page_link contains a pointer to the next sg
 * table list. Otherwise the next entry is at sg + 1.
 *
 * If bit 1 is set, then this sg entry is the last element in a list.
 *
 * See sg_next().
 *
 */

#define SG_CHAIN	0x01UL
#define SG_END		0x02UL

/*
 * We overload the LSB of the page pointer to indicate whether it's
 * a valid sg entry, or whether it points to the start of a new scatterlist.
 * Those low bits are there for everyone! (thanks mason :-)
 */
#define sg_is_chain(sg)		((sg)->page_link & SG_CHAIN)
#define sg_is_last(sg)		((sg)->page_link & SG_END)
#define sg_chain_ptr(sg)	\
	((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END)))

/**
 * sg_assign_page - Assign a given page to an SG entry
 * @sg:		    SG entry
 * @page:	    The page
 *
 * Description:
 *   Assign page to sg entry. Also see sg_set_page(), the most commonly used
 *   variant.
 *
 **/
static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
{
	unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END);

	/*
	 * In order for the low bit stealing approach to work, pages
	 * must be aligned at a 32-bit boundary as a minimum.
	 */
	BUG_ON((unsigned long) page & (SG_CHAIN | SG_END));
#ifdef CONFIG_DEBUG_SG
	BUG_ON(sg_is_chain(sg));
#endif
	sg->page_link = page_link | (unsigned long) page;
}

/**
 * sg_set_page - Set sg entry to point at given page
 * @sg:		 SG entry
 * @page:	 The page
 * @len:	 Length of data
 * @offset:	 Offset into page
 *
 * Description:
 *   Use this function to set an sg entry pointing at a page, never assign
 *   the page directly. We encode sg table information in the lower bits
 *   of the page pointer. See sg_page() for looking up the page belonging
 *   to an sg entry.
 *
 **/
static inline void sg_set_page(struct scatterlist *sg, struct page *page,
			       unsigned int len, unsigned int offset)
{
	sg_assign_page(sg, page);
	sg->offset = offset;
	sg->length = len;
}

static inline struct page *sg_page(struct scatterlist *sg)
{
#ifdef CONFIG_DEBUG_SG
	BUG_ON(sg_is_chain(sg));
#endif
	return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END));
}

/**
 * sg_set_buf - Set sg entry to point at given data
 * @sg:		 SG entry
 * @buf:	 Data
 * @buflen:	 Data length
 *
 **/
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
			      unsigned int buflen)
{
#ifdef CONFIG_DEBUG_SG
	BUG_ON(!virt_addr_valid(buf));
#endif
	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}

/*
 * Loop over each sg element, following the pointer to a new list if necessary
 */
#define for_each_sg(sglist, sg, nr, __i)	\
	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))

/**
 * sg_chain - Chain two sglists together
 * @prv:	First scatterlist
 * @prv_nents:	Number of entries in prv
 * @sgl:	Second scatterlist
 *
 * Description:
 *   Links @prv@ and @sgl@ together, to form a longer scatterlist.
 *
 **/
static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
			    struct scatterlist *sgl)
{
	/*
	 * offset and length are unused for chain entry.  Clear them.
	 */
	prv[prv_nents - 1].offset = 0;
	prv[prv_nents - 1].length = 0;

	/*
	 * Set lowest bit to indicate a link pointer, and make sure to clear
	 * the termination bit if it happens to be set.
	 */
	prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN)
					& ~SG_END;
}

/**
 * sg_mark_end - Mark the end of the scatterlist
 * @sg:		 SG entryScatterlist
 *
 * Description:
 *   Marks the passed in sg entry as the termination point for the sg
 *   table. A call to sg_next() on this entry will return NULL.
 *
 **/
static inline void sg_mark_end(struct scatterlist *sg)
{
	/*
	 * Set termination bit, clear potential chain bit
	 */
	sg->page_link |= SG_END;
	sg->page_link &= ~SG_CHAIN;
}

/**
 * sg_unmark_end - Undo setting the end of the scatterlist
 * @sg:		 SG entryScatterlist
 *
 * Description:
 *   Removes the termination marker from the given entry of the scatterlist.
 *
 **/
static inline void sg_unmark_end(struct scatterlist *sg)
{
	sg->page_link &= ~SG_END;
}

/**
 * sg_phys - Return physical address of an sg entry
 * @sg:	     SG entry
 *
 * Description:
 *   This calls page_to_phys() on the page in this sg entry, and adds the
 *   sg offset. The caller must know that it is legal to call page_to_phys()
 *   on the sg page.
 *
 **/
static inline dma_addr_t sg_phys(struct scatterlist *sg)
{
	return page_to_phys(sg_page(sg)) + sg->offset;
}

/**
 * sg_virt - Return virtual address of an sg entry
 * @sg:      SG entry
 *
 * Description:
 *   This calls page_address() on the page in this sg entry, and adds the
 *   sg offset. The caller must know that the sg page has a valid virtual
 *   mapping.
 *
 **/
static inline void *sg_virt(struct scatterlist *sg)
{
	return page_address(sg_page(sg)) + sg->offset;
}

/**
 * sg_init_marker - Initialize markers in sg table
 * @sgl:	   The SG table
 * @nents:	   Number of entries in table
 *
 **/
static inline void sg_init_marker(struct scatterlist *sgl,
				  unsigned int nents)
{
	sg_mark_end(&sgl[nents - 1]);
}

int sg_nents(struct scatterlist *sg);
int sg_nents_for_len(struct scatterlist *sg, u64 len);
struct scatterlist *sg_next(struct scatterlist *);
struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
void sg_init_table(struct scatterlist *, unsigned int);
void sg_init_one(struct scatterlist *, const void *, unsigned int);
int sg_split(struct scatterlist *in, const int in_mapped_nents,
	     const off_t skip, const int nb_splits,
	     const size_t *split_sizes,
	     struct scatterlist **out, int *out_mapped_nents,
	     gfp_t gfp_mask);

typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
typedef void (sg_free_fn)(struct scatterlist *, unsigned int);

void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *);
void sg_free_table(struct sg_table *);
int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
		     struct scatterlist *, gfp_t, sg_alloc_fn *);
int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
				unsigned int n_pages, unsigned int offset,
				unsigned long size, unsigned int max_segment,
				gfp_t gfp_mask);
int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
			      unsigned int n_pages, unsigned int offset,
			      unsigned long size, gfp_t gfp_mask);

#ifdef CONFIG_SGL_ALLOC
struct scatterlist *sgl_alloc_order(unsigned long long length,
				    unsigned int order, bool chainable,
				    gfp_t gfp, unsigned int *nent_p);
struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
			      unsigned int *nent_p);
void sgl_free_n_order(struct scatterlist *sgl, int nents, int order);
void sgl_free_order(struct scatterlist *sgl, int order);
void sgl_free(struct scatterlist *sgl);
#endif /* CONFIG_SGL_ALLOC */

size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
		      size_t buflen, off_t skip, bool to_buffer);

size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
			   const void *buf, size_t buflen);
size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
			 void *buf, size_t buflen);

size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
			    const void *buf, size_t buflen, off_t skip);
size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
			  void *buf, size_t buflen, off_t skip);
size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
		       size_t buflen, off_t skip);

/*
 * Maximum number of entries that will be allocated in one piece, if
 * a list larger than this is required then chaining will be utilized.
 */
#define SG_MAX_SINGLE_ALLOC		(PAGE_SIZE / sizeof(struct scatterlist))

/*
 * The maximum number of SG segments that we will put inside a
 * scatterlist (unless chaining is used). Should ideally fit inside a
 * single page, to avoid a higher order allocation.  We could define this
 * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order.  The
 * minimum value is 32
 */
#define SG_CHUNK_SIZE	128

/*
 * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit
 * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
 */
#ifdef CONFIG_ARCH_HAS_SG_CHAIN
#define SG_MAX_SEGMENTS	2048
#else
#define SG_MAX_SEGMENTS	SG_CHUNK_SIZE
#endif

#ifdef CONFIG_SG_POOL
void sg_free_table_chained(struct sg_table *table, bool first_chunk);
int sg_alloc_table_chained(struct sg_table *table, int nents,
			   struct scatterlist *first_chunk);
#endif

/*
 * sg page iterator
 *
 * Iterates over sg entries page-by-page.  On each successful iteration,
 * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter)
 * to get the current page and its dma address. @piter->sg will point to the
 * sg holding this page and @piter->sg_pgoffset to the page's page offset
 * within the sg. The iteration will stop either when a maximum number of sg
 * entries was reached or a terminating sg (sg_last(sg) == true) was reached.
 */
struct sg_page_iter {
	struct scatterlist	*sg;		/* sg holding the page */
	unsigned int		sg_pgoffset;	/* page offset within the sg */

	/* these are internal states, keep away */
	unsigned int		__nents;	/* remaining sg entries */
	int			__pg_advance;	/* nr pages to advance at the
						 * next step */
};

bool __sg_page_iter_next(struct sg_page_iter *piter);
void __sg_page_iter_start(struct sg_page_iter *piter,
			  struct scatterlist *sglist, unsigned int nents,
			  unsigned long pgoffset);
/**
 * sg_page_iter_page - get the current page held by the page iterator
 * @piter:	page iterator holding the page
 */
static inline struct page *sg_page_iter_page(struct sg_page_iter *piter)
{
	return nth_page(sg_page(piter->sg), piter->sg_pgoffset);
}

/**
 * sg_page_iter_dma_address - get the dma address of the current page held by
 * the page iterator.
 * @piter:	page iterator holding the page
 */
static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter)
{
	return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT);
}

/**
 * for_each_sg_page - iterate over the pages of the given sg list
 * @sglist:	sglist to iterate over
 * @piter:	page iterator to hold current page, sg, sg_pgoffset
 * @nents:	maximum number of sg entries to iterate over
 * @pgoffset:	starting page offset
 */
#define for_each_sg_page(sglist, piter, nents, pgoffset)		   \
	for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
	     __sg_page_iter_next(piter);)

/*
 * Mapping sg iterator
 *
 * Iterates over sg entries mapping page-by-page.  On each successful
 * iteration, @miter->page points to the mapped page and
 * @miter->length bytes of data can be accessed at @miter->addr.  As
 * long as an interation is enclosed between start and stop, the user
 * is free to choose control structure and when to stop.
 *
 * @miter->consumed is set to @miter->length on each iteration.  It
 * can be adjusted if the user can't consume all the bytes in one go.
 * Also, a stopped iteration can be resumed by calling next on it.
 * This is useful when iteration needs to release all resources and
 * continue later (e.g. at the next interrupt).
 */

#define SG_MITER_ATOMIC		(1 << 0)	 /* use kmap_atomic */
#define SG_MITER_TO_SG		(1 << 1)	/* flush back to phys on unmap */
#define SG_MITER_FROM_SG	(1 << 2)	/* nop */

struct sg_mapping_iter {
	/* the following three fields can be accessed directly */
	struct page		*page;		/* currently mapped page */
	void			*addr;		/* pointer to the mapped area */
	size_t			length;		/* length of the mapped area */
	size_t			consumed;	/* number of consumed bytes */
	struct sg_page_iter	piter;		/* page iterator */

	/* these are internal states, keep away */
	unsigned int		__offset;	/* offset within page */
	unsigned int		__remaining;	/* remaining bytes on page */
	unsigned int		__flags;
};

void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
		    unsigned int nents, unsigned int flags);
bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset);
bool sg_miter_next(struct sg_mapping_iter *miter);
void sg_miter_stop(struct sg_mapping_iter *miter);

#endif /* _LINUX_SCATTERLIST_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _LINUX_SCATTERLIST_H
	3	#define _LINUX_SCATTERLIST_H
	4
187f1882	5	#include <linux/string.h>
84be456f	6	#include <linux/types.h>
187f1882 PG	7	#include <linux/bug.h>
187f1882 PG	8	#include <linux/mm.h>
18dabf47 JA	9	#include <asm/io.h>
18dabf47 JA	10
84be456f	11	struct scatterlist {
84be456f CH	12	unsigned long page_link;
	13	unsigned int offset;
	14	unsigned int length;
	15	dma_addr_t dma_address;
	16	#ifdef CONFIG_NEED_SG_DMA_LENGTH
	17	unsigned int dma_length;
	18	#endif
	19	};
	20
c125906b TU	21	/*
	22	* Since the above length field is an unsigned int, below we define the maximum
	23	* length in bytes that can be stored in one scatterlist entry.
	24	*/
	25	#define SCATTERLIST_MAX_SEGMENT (UINT_MAX & PAGE_MASK)
	26
84be456f CH	27	/*
	28	* These macros should be used after a dma_map_sg call has been done
	29	* to get bus addresses of each of the SG entries and their lengths.
	30	* You should only work with the number of sg entries dma_map_sg
	31	* returns, or alternatively stop on the first sg_dma_len(sg) which
	32	* is 0.
	33	*/
	34	#define sg_dma_address(sg) ((sg)->dma_address)
	35
	36	#ifdef CONFIG_NEED_SG_DMA_LENGTH
	37	#define sg_dma_len(sg) ((sg)->dma_length)
	38	#else
	39	#define sg_dma_len(sg) ((sg)->length)
	40	#endif
	41
0db9299f JA	42	struct sg_table {
	43	struct scatterlist sgl; / the list */
	44	unsigned int nents; /* number of mapped entries */
	45	unsigned int orig_nents; /* original size of list */
	46	};
	47
18dabf47 JA	48	/*
	49	* Notes on SG table design.
	50	*
84be456f CH	51	* We use the unsigned long page_link field in the scatterlist struct to place
	52	* the page pointer AND encode information about the sg table as well. The two
	53	* lower bits are reserved for this information.
18dabf47 JA	54	*
	55	* If bit 0 is set, then the page_link contains a pointer to the next sg
	56	* table list. Otherwise the next entry is at sg + 1.
	57	*
	58	* If bit 1 is set, then this sg entry is the last element in a list.
	59	*
	60	* See sg_next().
	61	*
	62	*/
1da177e4	63
723fbf56 AK	64	#define SG_CHAIN 0x01UL
723fbf56 AK	65	#define SG_END 0x02UL
d6ec0842	66
645a8d94 TH	67	/*
	68	* We overload the LSB of the page pointer to indicate whether it's
	69	* a valid sg entry, or whether it points to the start of a new scatterlist.
	70	* Those low bits are there for everyone! (thanks mason :-)
	71	*/
723fbf56 AK	72	#define sg_is_chain(sg) ((sg)->page_link & SG_CHAIN)
723fbf56 AK	73	#define sg_is_last(sg) ((sg)->page_link & SG_END)
645a8d94	74	#define sg_chain_ptr(sg) \
723fbf56	75	((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN \| SG_END)))
645a8d94	76
82f66fbe	77	/**
642f1490 JA	78	* sg_assign_page - Assign a given page to an SG entry
	79	* @sg: SG entry
	80	* @page: The page
82f66fbe JA	81	*
82f66fbe JA	82	* Description:
642f1490 JA	83	* Assign page to sg entry. Also see sg_set_page(), the most commonly used
642f1490 JA	84	* variant.
82f66fbe JA	85	*
82f66fbe JA	86	**/
642f1490	87	static inline void sg_assign_page(struct scatterlist sg, struct page page)
82f66fbe	88	{
723fbf56	89	unsigned long page_link = sg->page_link & (SG_CHAIN \| SG_END);
18dabf47	90
de26103d JA	91	/*
	92	* In order for the low bit stealing approach to work, pages
	93	* must be aligned at a 32-bit boundary as a minimum.
	94	*/
723fbf56	95	BUG_ON((unsigned long) page & (SG_CHAIN \| SG_END));
d6ec0842	96	#ifdef CONFIG_DEBUG_SG
645a8d94	97	BUG_ON(sg_is_chain(sg));
d6ec0842	98	#endif
18dabf47	99	sg->page_link = page_link \| (unsigned long) page;
82f66fbe JA	100	}
82f66fbe JA	101
642f1490 JA	102	/**
	103	* sg_set_page - Set sg entry to point at given page
	104	* @sg: SG entry
	105	* @page: The page
	106	* @len: Length of data
	107	* @offset: Offset into page
	108	*
	109	* Description:
	110	* Use this function to set an sg entry pointing at a page, never assign
	111	* the page directly. We encode sg table information in the lower bits
	112	* of the page pointer. See sg_page() for looking up the page belonging
	113	* to an sg entry.
	114	*
	115	**/
	116	static inline void sg_set_page(struct scatterlist sg, struct page page,
	117	unsigned int len, unsigned int offset)
	118	{
	119	sg_assign_page(sg, page);
	120	sg->offset = offset;
	121	sg->length = len;
	122	}
	123
645a8d94 TH	124	static inline struct page sg_page(struct scatterlist sg)
	125	{
	126	#ifdef CONFIG_DEBUG_SG
645a8d94 TH	127	BUG_ON(sg_is_chain(sg));
645a8d94 TH	128	#endif
723fbf56	129	return (struct page *)((sg)->page_link & ~(SG_CHAIN \| SG_END));
645a8d94	130	}
82f66fbe	131
18dabf47 JA	132	/**
	133	* sg_set_buf - Set sg entry to point at given data
	134	* @sg: SG entry
	135	* @buf: Data
	136	* @buflen: Data length
	137	*
	138	**/
03fd9cee	139	static inline void sg_set_buf(struct scatterlist sg, const void buf,
d32311fe HX	140	unsigned int buflen)
d32311fe HX	141	{
ac4e97ab RR	142	#ifdef CONFIG_DEBUG_SG
	143	BUG_ON(!virt_addr_valid(buf));
	144	#endif
642f1490	145	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
1da177e4 LT	146	}
1da177e4 LT	147
96b418c9 JA	148	/*
	149	* Loop over each sg element, following the pointer to a new list if necessary
	150	*/
	151	#define for_each_sg(sglist, sg, nr, __i) \
	152	for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
	153
70eb8040 JA	154	/**
	155	* sg_chain - Chain two sglists together
	156	* @prv: First scatterlist
	157	* @prv_nents: Number of entries in prv
	158	* @sgl: Second scatterlist
	159	*
18dabf47 JA	160	* Description:
18dabf47 JA	161	* Links @prv@ and @sgl@ together, to form a longer scatterlist.
70eb8040	162	*
18dabf47	163	**/
70eb8040 JA	164	static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
	165	struct scatterlist *sgl)
	166	{
645a8d94 TH	167	/*
	168	* offset and length are unused for chain entry. Clear them.
	169	*/
b801a1e7 RR	170	prv[prv_nents - 1].offset = 0;
b801a1e7 RR	171	prv[prv_nents - 1].length = 0;
645a8d94	172
73fd546a JA	173	/*
	174	* Set lowest bit to indicate a link pointer, and make sure to clear
	175	* the termination bit if it happens to be set.
	176	*/
723fbf56 AK	177	prv[prv_nents - 1].page_link = ((unsigned long) sgl \| SG_CHAIN)
723fbf56 AK	178	& ~SG_END;
70eb8040 JA	179	}
70eb8040 JA	180
82f66fbe JA	181	/**
82f66fbe JA	182	* sg_mark_end - Mark the end of the scatterlist
c46f2334	183	* @sg: SG entryScatterlist
82f66fbe JA	184	*
82f66fbe JA	185	* Description:
c46f2334 JA	186	* Marks the passed in sg entry as the termination point for the sg
c46f2334 JA	187	* table. A call to sg_next() on this entry will return NULL.
82f66fbe JA	188	*
82f66fbe JA	189	**/
c46f2334	190	static inline void sg_mark_end(struct scatterlist *sg)
82f66fbe	191	{
c46f2334 JA	192	/*
	193	* Set termination bit, clear potential chain bit
	194	*/
723fbf56 AK	195	sg->page_link \|= SG_END;
723fbf56 AK	196	sg->page_link &= ~SG_CHAIN;
82f66fbe JA	197	}
82f66fbe JA	198
c8164d89 PB	199	/**
	200	* sg_unmark_end - Undo setting the end of the scatterlist
	201	* @sg: SG entryScatterlist
	202	*
	203	* Description:
	204	* Removes the termination marker from the given entry of the scatterlist.
	205	*
	206	**/
	207	static inline void sg_unmark_end(struct scatterlist *sg)
	208	{
723fbf56	209	sg->page_link &= ~SG_END;
c8164d89 PB	210	}
c8164d89 PB	211
82f66fbe JA	212	/**
	213	* sg_phys - Return physical address of an sg entry
	214	* @sg: SG entry
	215	*
	216	* Description:
	217	* This calls page_to_phys() on the page in this sg entry, and adds the
	218	* sg offset. The caller must know that it is legal to call page_to_phys()
	219	* on the sg page.
	220	*
	221	**/
85cdffcd	222	static inline dma_addr_t sg_phys(struct scatterlist *sg)
82f66fbe JA	223	{
	224	return page_to_phys(sg_page(sg)) + sg->offset;
	225	}
	226
	227	/**
	228	* sg_virt - Return virtual address of an sg entry
18dabf47	229	* @sg: SG entry
82f66fbe JA	230	*
	231	* Description:
	232	* This calls page_address() on the page in this sg entry, and adds the
	233	* sg offset. The caller must know that the sg page has a valid virtual
	234	* mapping.
	235	*
	236	**/
	237	static inline void sg_virt(struct scatterlist sg)
	238	{
	239	return page_address(sg_page(sg)) + sg->offset;
	240	}
	241
f3851786 PB	242	/**
	243	* sg_init_marker - Initialize markers in sg table
	244	* @sgl: The SG table
	245	* @nents: Number of entries in table
	246	*
	247	**/
	248	static inline void sg_init_marker(struct scatterlist *sgl,
	249	unsigned int nents)
	250	{
f3851786 PB	251	sg_mark_end(&sgl[nents - 1]);
	252	}
	253
2e484610	254	int sg_nents(struct scatterlist *sg);
cfaed10d	255	int sg_nents_for_len(struct scatterlist *sg, u64 len);
0db9299f JA	256	struct scatterlist sg_next(struct scatterlist );
	257	struct scatterlist sg_last(struct scatterlist s, unsigned int);
	258	void sg_init_table(struct scatterlist *, unsigned int);
	259	void sg_init_one(struct scatterlist , const void , unsigned int);
f8bcbe62 RJ	260	int sg_split(struct scatterlist *in, const int in_mapped_nents,
	261	const off_t skip, const int nb_splits,
	262	const size_t *split_sizes,
	263	struct scatterlist *out, int out_mapped_nents,
	264	gfp_t gfp_mask);
0db9299f JA	265
	266	typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
	267	typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
	268
c53c6d6a	269	void __sg_free_table(struct sg_table , unsigned int, bool, sg_free_fn );
0db9299f	270	void sg_free_table(struct sg_table *);
c53c6d6a CH	271	int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
c53c6d6a CH	272	struct scatterlist , gfp_t, sg_alloc_fn );
0db9299f	273	int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
89d8589c TU	274	int __sg_alloc_table_from_pages(struct sg_table sgt, struct page *pages,
	275	unsigned int n_pages, unsigned int offset,
	276	unsigned long size, unsigned int max_segment,
	277	gfp_t gfp_mask);
	278	int sg_alloc_table_from_pages(struct sg_table sgt, struct page *pages,
	279	unsigned int n_pages, unsigned int offset,
	280	unsigned long size, gfp_t gfp_mask);
0db9299f	281
e80a0af4 BVA	282	#ifdef CONFIG_SGL_ALLOC
	283	struct scatterlist *sgl_alloc_order(unsigned long long length,
	284	unsigned int order, bool chainable,
	285	gfp_t gfp, unsigned int *nent_p);
	286	struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
	287	unsigned int *nent_p);
8c7a8d1c	288	void sgl_free_n_order(struct scatterlist *sgl, int nents, int order);
e80a0af4 BVA	289	void sgl_free_order(struct scatterlist *sgl, int order);
	290	void sgl_free(struct scatterlist *sgl);
	291	#endif /* CONFIG_SGL_ALLOC */
	292
386ecb12 DG	293	size_t sg_copy_buffer(struct scatterlist sgl, unsigned int nents, void buf,
	294	size_t buflen, off_t skip, bool to_buffer);
	295
b1adaf65	296	size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
2a1bf8f9	297	const void *buf, size_t buflen);
b1adaf65 FT	298	size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
	299	void *buf, size_t buflen);
	300
df642cea	301	size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
2a1bf8f9	302	const void *buf, size_t buflen, off_t skip);
df642cea AM	303	size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
df642cea AM	304	void *buf, size_t buflen, off_t skip);
0945e569 JT	305	size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
0945e569 JT	306	size_t buflen, off_t skip);
df642cea	307
0db9299f JA	308	/*
	309	* Maximum number of entries that will be allocated in one piece, if
	310	* a list larger than this is required then chaining will be utilized.
	311	*/
	312	#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
	313
9b1d6c89 ML	314	/*
	315	* The maximum number of SG segments that we will put inside a
	316	* scatterlist (unless chaining is used). Should ideally fit inside a
	317	* single page, to avoid a higher order allocation. We could define this
	318	* to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The
	319	* minimum value is 32
	320	*/
	321	#define SG_CHUNK_SIZE 128
	322
	323	/*
	324	* Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit
	325	* is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
	326	*/
	327	#ifdef CONFIG_ARCH_HAS_SG_CHAIN
	328	#define SG_MAX_SEGMENTS 2048
	329	#else
	330	#define SG_MAX_SEGMENTS SG_CHUNK_SIZE
	331	#endif
	332
	333	#ifdef CONFIG_SG_POOL
	334	void sg_free_table_chained(struct sg_table *table, bool first_chunk);
	335	int sg_alloc_table_chained(struct sg_table *table, int nents,
	336	struct scatterlist *first_chunk);
	337	#endif
	338
a321e91b ID	339	/*
	340	* sg page iterator
	341	*
	342	* Iterates over sg entries page-by-page. On each successful iteration,
2db76d7c ID	343	* you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter)
	344	* to get the current page and its dma address. @piter->sg will point to the
	345	* sg holding this page and @piter->sg_pgoffset to the page's page offset
	346	* within the sg. The iteration will stop either when a maximum number of sg
	347	* entries was reached or a terminating sg (sg_last(sg) == true) was reached.
a321e91b ID	348	*/
a321e91b ID	349	struct sg_page_iter {
a321e91b ID	350	struct scatterlist sg; / sg holding the page */
	351	unsigned int sg_pgoffset; /* page offset within the sg */
	352
	353	/* these are internal states, keep away */
	354	unsigned int __nents; /* remaining sg entries */
	355	int __pg_advance; /* nr pages to advance at the
	356	* next step */
	357	};
	358
	359	bool __sg_page_iter_next(struct sg_page_iter *piter);
	360	void __sg_page_iter_start(struct sg_page_iter *piter,
	361	struct scatterlist *sglist, unsigned int nents,
	362	unsigned long pgoffset);
2db76d7c ID	363	/**
	364	* sg_page_iter_page - get the current page held by the page iterator
	365	* @piter: page iterator holding the page
	366	*/
	367	static inline struct page sg_page_iter_page(struct sg_page_iter piter)
	368	{
	369	return nth_page(sg_page(piter->sg), piter->sg_pgoffset);
	370	}
	371
	372	/**
	373	* sg_page_iter_dma_address - get the dma address of the current page held by
	374	* the page iterator.
	375	* @piter: page iterator holding the page
	376	*/
	377	static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter)
	378	{
	379	return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT);
	380	}
a321e91b ID	381
	382	/**
	383	* for_each_sg_page - iterate over the pages of the given sg list
	384	* @sglist: sglist to iterate over
	385	* @piter: page iterator to hold current page, sg, sg_pgoffset
	386	* @nents: maximum number of sg entries to iterate over
	387	* @pgoffset: starting page offset
	388	*/
	389	#define for_each_sg_page(sglist, piter, nents, pgoffset) \
	390	for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
	391	__sg_page_iter_next(piter);)
137d3edb TH	392
	393	/*
	394	* Mapping sg iterator
	395	*
	396	* Iterates over sg entries mapping page-by-page. On each successful
	397	* iteration, @miter->page points to the mapped page and
	398	* @miter->length bytes of data can be accessed at @miter->addr. As
	399	* long as an interation is enclosed between start and stop, the user
	400	* is free to choose control structure and when to stop.
	401	*
	402	* @miter->consumed is set to @miter->length on each iteration. It
	403	* can be adjusted if the user can't consume all the bytes in one go.
	404	* Also, a stopped iteration can be resumed by calling next on it.
	405	* This is useful when iteration needs to release all resources and
	406	* continue later (e.g. at the next interrupt).
	407	*/
	408
	409	#define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */
6de7e356 SAS	410	#define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */
6de7e356 SAS	411	#define SG_MITER_FROM_SG (1 << 2) /* nop */
137d3edb TH	412
	413	struct sg_mapping_iter {
	414	/* the following three fields can be accessed directly */
	415	struct page page; / currently mapped page */
	416	void addr; / pointer to the mapped area */
	417	size_t length; /* length of the mapped area */
	418	size_t consumed; /* number of consumed bytes */
4225fc85	419	struct sg_page_iter piter; /* page iterator */
137d3edb TH	420
137d3edb TH	421	/* these are internal states, keep away */
4225fc85 ID	422	unsigned int __offset; /* offset within page */
4225fc85 ID	423	unsigned int __remaining; /* remaining bytes on page */
137d3edb TH	424	unsigned int __flags;
	425	};
	426
	427	void sg_miter_start(struct sg_mapping_iter miter, struct scatterlist sgl,
	428	unsigned int nents, unsigned int flags);
0d6077f8	429	bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset);
137d3edb TH	430	bool sg_miter_next(struct sg_mapping_iter *miter);
	431	void sg_miter_stop(struct sg_mapping_iter *miter);
	432
1da177e4	433	#endif /* _LINUX_SCATTERLIST_H */