[mirror_ubuntu-jammy-kernel.git] / include / linux / uio.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *	Berkeley style UIO structures	-	Alan Cox 1994.
 */
#ifndef __LINUX_UIO_H
#define __LINUX_UIO_H

#include <linux/kernel.h>
#include <linux/thread_info.h>
#include <uapi/linux/uio.h>

struct page;
struct pipe_inode_info;

struct kvec {
	void *iov_base; /* and that should *never* hold a userland pointer */
	size_t iov_len;
};

enum iter_type {
	/* iter types */
	ITER_IOVEC,
	ITER_KVEC,
	ITER_BVEC,
	ITER_PIPE,
	ITER_XARRAY,
	ITER_DISCARD,
};

struct iov_iter_state {
	size_t iov_offset;
	size_t count;
	unsigned long nr_segs;
};

struct iov_iter {
	u8 iter_type;
	bool data_source;
	size_t iov_offset;
	size_t count;
	union {
		const struct iovec *iov;
		const struct kvec *kvec;
		const struct bio_vec *bvec;
		struct xarray *xarray;
		struct pipe_inode_info *pipe;
	};
	union {
		unsigned long nr_segs;
		struct {
			unsigned int head;
			unsigned int start_head;
		};
		loff_t xarray_start;
	};
};

static inline enum iter_type iov_iter_type(const struct iov_iter *i)
{
	return i->iter_type;
}

static inline void iov_iter_save_state(struct iov_iter *iter,
				       struct iov_iter_state *state)
{
	state->iov_offset = iter->iov_offset;
	state->count = iter->count;
	state->nr_segs = iter->nr_segs;
}

static inline bool iter_is_iovec(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_IOVEC;
}

static inline bool iov_iter_is_kvec(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_KVEC;
}

static inline bool iov_iter_is_bvec(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_BVEC;
}

static inline bool iov_iter_is_pipe(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_PIPE;
}

static inline bool iov_iter_is_discard(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_DISCARD;
}

static inline bool iov_iter_is_xarray(const struct iov_iter *i)
{
	return iov_iter_type(i) == ITER_XARRAY;
}

static inline unsigned char iov_iter_rw(const struct iov_iter *i)
{
	return i->data_source ? WRITE : READ;
}

/*
 * Total number of bytes covered by an iovec.
 *
 * NOTE that it is not safe to use this function until all the iovec's
 * segment lengths have been validated.  Because the individual lengths can
 * overflow a size_t when added together.
 */
static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
{
	unsigned long seg;
	size_t ret = 0;

	for (seg = 0; seg < nr_segs; seg++)
		ret += iov[seg].iov_len;
	return ret;
}

static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
{
	return (struct iovec) {
		.iov_base = iter->iov->iov_base + iter->iov_offset,
		.iov_len = min(iter->count,
			       iter->iov->iov_len - iter->iov_offset),
	};
}

size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
				  size_t bytes, struct iov_iter *i);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
void iov_iter_revert(struct iov_iter *i, size_t bytes);
int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
			 struct iov_iter *i);
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
			 struct iov_iter *i);

size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);

static __always_inline __must_check
size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, true)))
		return 0;
	else
		return _copy_to_iter(addr, bytes, i);
}

static __always_inline __must_check
size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, false)))
		return 0;
	else
		return _copy_from_iter(addr, bytes, i);
}

static __always_inline __must_check
bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
{
	size_t copied = copy_from_iter(addr, bytes, i);
	if (likely(copied == bytes))
		return true;
	iov_iter_revert(i, copied);
	return false;
}

static __always_inline __must_check
size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, false)))
		return 0;
	else
		return _copy_from_iter_nocache(addr, bytes, i);
}

static __always_inline __must_check
bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
	size_t copied = copy_from_iter_nocache(addr, bytes, i);
	if (likely(copied == bytes))
		return true;
	iov_iter_revert(i, copied);
	return false;
}

#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
/*
 * Note, users like pmem that depend on the stricter semantics of
 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
 * destination is flushed from the cache on return.
 */
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
#else
#define _copy_from_iter_flushcache _copy_from_iter_nocache
#endif

#ifdef CONFIG_ARCH_HAS_COPY_MC
size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
#else
#define _copy_mc_to_iter _copy_to_iter
#endif

static __always_inline __must_check
size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, false)))
		return 0;
	else
		return _copy_from_iter_flushcache(addr, bytes, i);
}

static __always_inline __must_check
size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, true)))
		return 0;
	else
		return _copy_mc_to_iter(addr, bytes, i);
}

size_t iov_iter_zero(size_t bytes, struct iov_iter *);
unsigned long iov_iter_alignment(const struct iov_iter *i);
unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
			unsigned long nr_segs, size_t count);
void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
			unsigned long nr_segs, size_t count);
void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
			unsigned long nr_segs, size_t count);
void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
			size_t count);
void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
		     loff_t start, size_t count);
ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
			size_t maxsize, unsigned maxpages, size_t *start);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
			size_t maxsize, size_t *start);
int iov_iter_npages(const struct iov_iter *i, int maxpages);
void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state);

const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);

static inline size_t iov_iter_count(const struct iov_iter *i)
{
	return i->count;
}

/*
 * Cap the iov_iter by given limit; note that the second argument is
 * *not* the new size - it's upper limit for such.  Passing it a value
 * greater than the amount of data in iov_iter is fine - it'll just do
 * nothing in that case.
 */
static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
{
	/*
	 * count doesn't have to fit in size_t - comparison extends both
	 * operands to u64 here and any value that would be truncated by
	 * conversion in assignement is by definition greater than all
	 * values of size_t, including old i->count.
	 */
	if (i->count > count)
		i->count = count;
}

/*
 * reexpand a previously truncated iterator; count must be no more than how much
 * we had shrunk it.
 */
static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
{
	i->count = count;
}

struct csum_state {
	__wsum csum;
	size_t off;
};

size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);

static __always_inline __must_check
bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
				  __wsum *csum, struct iov_iter *i)
{
	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
	if (likely(copied == bytes))
		return true;
	iov_iter_revert(i, copied);
	return false;
}
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
		struct iov_iter *i);

struct iovec *iovec_from_user(const struct iovec __user *uvector,
		unsigned long nr_segs, unsigned long fast_segs,
		struct iovec *fast_iov, bool compat);
ssize_t import_iovec(int type, const struct iovec __user *uvec,
		 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
		 struct iov_iter *i);
ssize_t __import_iovec(int type, const struct iovec __user *uvec,
		 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
		 struct iov_iter *i, bool compat);
int import_single_range(int type, void __user *buf, size_t len,
		 struct iovec *iov, struct iov_iter *i);

#endif
Commit	Line	Data
2874c5fd	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
1da177e4 LT	2	/*
1da177e4 LT	3	* Berkeley style UIO structures - Alan Cox 1994.
1da177e4	4	*/
607ca46e DH	5	#ifndef __LINUX_UIO_H
607ca46e DH	6	#define __LINUX_UIO_H
1da177e4	7
92236878	8	#include <linux/kernel.h>
aa28de27	9	#include <linux/thread_info.h>
607ca46e	10	#include <uapi/linux/uio.h>
1da177e4	11
92236878	12	struct page;
241699cd	13	struct pipe_inode_info;
812ed032 JS	14
	15	struct kvec {
	16	void iov_base; / and that should never hold a userland pointer */
	17	size_t iov_len;
	18	};
	19
00e23707	20	enum iter_type {
875f1d07	21	/* iter types */
8cd54c1c AV	22	ITER_IOVEC,
	23	ITER_KVEC,
	24	ITER_BVEC,
	25	ITER_PIPE,
	26	ITER_XARRAY,
	27	ITER_DISCARD,
62a8067a AV	28	};
62a8067a AV	29
8fb0f47a JA	30	struct iov_iter_state {
	31	size_t iov_offset;
	32	size_t count;
	33	unsigned long nr_segs;
	34	};
	35
92236878	36	struct iov_iter {
8cd54c1c AV	37	u8 iter_type;
8cd54c1c AV	38	bool data_source;
92236878 KO	39	size_t iov_offset;
92236878 KO	40	size_t count;
62a8067a AV	41	union {
62a8067a AV	42	const struct iovec *iov;
a280455f	43	const struct kvec *kvec;
62a8067a	44	const struct bio_vec *bvec;
7ff50620	45	struct xarray *xarray;
241699cd AV	46	struct pipe_inode_info *pipe;
	47	};
	48	union {
	49	unsigned long nr_segs;
27c0e374	50	struct {
8cefc107 DH	51	unsigned int head;
8cefc107 DH	52	unsigned int start_head;
27c0e374	53	};
7ff50620	54	loff_t xarray_start;
62a8067a	55	};
92236878 KO	56	};
92236878 KO	57
00e23707 DH	58	static inline enum iter_type iov_iter_type(const struct iov_iter *i)
00e23707 DH	59	{
8cd54c1c	60	return i->iter_type;
00e23707 DH	61	}
00e23707 DH	62
8fb0f47a JA	63	static inline void iov_iter_save_state(struct iov_iter *iter,
	64	struct iov_iter_state *state)
	65	{
	66	state->iov_offset = iter->iov_offset;
	67	state->count = iter->count;
	68	state->nr_segs = iter->nr_segs;
	69	}
	70
00e23707 DH	71	static inline bool iter_is_iovec(const struct iov_iter *i)
	72	{
	73	return iov_iter_type(i) == ITER_IOVEC;
	74	}
	75
	76	static inline bool iov_iter_is_kvec(const struct iov_iter *i)
	77	{
	78	return iov_iter_type(i) == ITER_KVEC;
	79	}
	80
	81	static inline bool iov_iter_is_bvec(const struct iov_iter *i)
	82	{
	83	return iov_iter_type(i) == ITER_BVEC;
	84	}
	85
	86	static inline bool iov_iter_is_pipe(const struct iov_iter *i)
	87	{
	88	return iov_iter_type(i) == ITER_PIPE;
	89	}
	90
9ea9ce04 DH	91	static inline bool iov_iter_is_discard(const struct iov_iter *i)
	92	{
	93	return iov_iter_type(i) == ITER_DISCARD;
	94	}
	95
7ff50620 DH	96	static inline bool iov_iter_is_xarray(const struct iov_iter *i)
	97	{
	98	return iov_iter_type(i) == ITER_XARRAY;
	99	}
	100
00e23707 DH	101	static inline unsigned char iov_iter_rw(const struct iov_iter *i)
00e23707 DH	102	{
8cd54c1c	103	return i->data_source ? WRITE : READ;
00e23707 DH	104	}
00e23707 DH	105
1da177e4 LT	106	/*
	107	* Total number of bytes covered by an iovec.
	108	*
	109	* NOTE that it is not safe to use this function until all the iovec's
	110	* segment lengths have been validated. Because the individual lengths can
	111	* overflow a size_t when added together.
	112	*/
	113	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	114	{
	115	unsigned long seg;
	116	size_t ret = 0;
	117
	118	for (seg = 0; seg < nr_segs; seg++)
	119	ret += iov[seg].iov_len;
	120	return ret;
	121	}
	122
92236878 KO	123	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	124	{
	125	return (struct iovec) {
	126	.iov_base = iter->iov->iov_base + iter->iov_offset,
	127	.iov_len = min(iter->count,
	128	iter->iov->iov_len - iter->iov_offset),
	129	};
	130	}
	131
f0b65f39 AV	132	size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
f0b65f39 AV	133	size_t bytes, struct iov_iter *i);
92236878	134	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	135	void iov_iter_revert(struct iov_iter *i, size_t bytes);
8409a0d2	136	int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
92236878	137	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	138	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	139	struct iov_iter *i);
f0d1bec9 AV	140	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	141	struct iov_iter *i);
aa28de27 AV	142
	143	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	144	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
aa28de27	145	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
aa28de27 AV	146
	147	static __always_inline __must_check
	148	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	149	{
	150	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	151	return 0;
aa28de27 AV	152	else
	153	return _copy_to_iter(addr, bytes, i);
	154	}
	155
	156	static __always_inline __must_check
	157	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	158	{
	159	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	160	return 0;
aa28de27 AV	161	else
	162	return _copy_from_iter(addr, bytes, i);
	163	}
	164
	165	static __always_inline __must_check
	166	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	167	{
4b6c132b AV	168	size_t copied = copy_from_iter(addr, bytes, i);
	169	if (likely(copied == bytes))
	170	return true;
	171	iov_iter_revert(i, copied);
	172	return false;
aa28de27 AV	173	}
	174
	175	static __always_inline __must_check
	176	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	177	{
	178	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	179	return 0;
aa28de27 AV	180	else
	181	return _copy_from_iter_nocache(addr, bytes, i);
	182	}
	183
	184	static __always_inline __must_check
	185	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	186	{
4b6c132b AV	187	size_t copied = copy_from_iter_nocache(addr, bytes, i);
	188	if (likely(copied == bytes))
	189	return true;
	190	iov_iter_revert(i, copied);
	191	return false;
aa28de27 AV	192	}
aa28de27 AV	193
0aed55af DW	194	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	195	/*
	196	* Note, users like pmem that depend on the stricter semantics of
	197	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	198	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	199	* destination is flushed from the cache on return.
	200	*/
6a37e940	201	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	202	#else
6a37e940 LT	203	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	204	#endif
	205
ec6347bb DW	206	#ifdef CONFIG_ARCH_HAS_COPY_MC
ec6347bb DW	207	size_t _copy_mc_to_iter(const void addr, size_t bytes, struct iov_iter i);
8780356e	208	#else
ec6347bb	209	#define _copy_mc_to_iter _copy_to_iter
8780356e DW	210	#endif
8780356e DW	211
6a37e940 LT	212	static __always_inline __must_check
6a37e940 LT	213	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	214	{
6a37e940	215	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	216	return 0;
6a37e940 LT	217	else
6a37e940 LT	218	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	219	}
6a37e940	220
8780356e	221	static __always_inline __must_check
ec6347bb	222	size_t copy_mc_to_iter(void addr, size_t bytes, struct iov_iter i)
8780356e	223	{
dfb06cba	224	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	225	return 0;
8780356e DW	226	else
ec6347bb	227	return _copy_mc_to_iter(addr, bytes, i);
8780356e DW	228	}
8780356e DW	229
c35e0248	230	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	231	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	232	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
aa563d7b	233	void iov_iter_init(struct iov_iter i, unsigned int direction, const struct iovec iov,
71d8e532	234	unsigned long nr_segs, size_t count);
aa563d7b	235	void iov_iter_kvec(struct iov_iter i, unsigned int direction, const struct kvec kvec,
05afcb77	236	unsigned long nr_segs, size_t count);
aa563d7b	237	void iov_iter_bvec(struct iov_iter i, unsigned int direction, const struct bio_vec bvec,
abb78f87	238	unsigned long nr_segs, size_t count);
aa563d7b	239	void iov_iter_pipe(struct iov_iter i, unsigned int direction, struct pipe_inode_info pipe,
241699cd	240	size_t count);
9ea9ce04	241	void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
7ff50620 DH	242	void iov_iter_xarray(struct iov_iter i, unsigned int direction, struct xarray xarray,
7ff50620 DH	243	loff_t start, size_t count);
7b2c99d1	244	ssize_t iov_iter_get_pages(struct iov_iter i, struct page *pages,
2c80929c	245	size_t maxsize, unsigned maxpages, size_t *start);
91f79c43 AV	246	ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
91f79c43 AV	247	size_t maxsize, size_t *start);
f67da30c	248	int iov_iter_npages(const struct iov_iter *i, int maxpages);
8fb0f47a	249	void iov_iter_restore(struct iov_iter i, struct iov_iter_state state);
92236878	250
4b8164b9 AV	251	const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);
4b8164b9 AV	252
b57332b4	253	static inline size_t iov_iter_count(const struct iov_iter *i)
92236878 KO	254	{
	255	return i->count;
	256	}
	257
0b86dbf6 AV	258	/*
	259	* Cap the iov_iter by given limit; note that the second argument is
	260	* not the new size - it's upper limit for such. Passing it a value
	261	* greater than the amount of data in iov_iter is fine - it'll just do
	262	* nothing in that case.
	263	*/
	264	static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
0c949334	265	{
0b86dbf6 AV	266	/*
	267	* count doesn't have to fit in size_t - comparison extends both
	268	* operands to u64 here and any value that would be truncated by
	269	* conversion in assignement is by definition greater than all
	270	* values of size_t, including old i->count.
	271	*/
7dedd3e1	272	if (i->count > count)
0c949334 AV	273	i->count = count;
	274	}
	275
b42b15fd AV	276	/*
	277	* reexpand a previously truncated iterator; count must be no more than how much
	278	* we had shrunk it.
	279	*/
	280	static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
	281	{
	282	i->count = count;
	283	}
52cbd23a WB	284
	285	struct csum_state {
	286	__wsum csum;
	287	size_t off;
	288	};
	289
	290	size_t csum_and_copy_to_iter(const void addr, size_t bytes, void csstate, struct iov_iter *i);
a604ec7e	291	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
4b6c132b AV	292
	293	static __always_inline __must_check
	294	bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
	295	__wsum csum, struct iov_iter i)
	296	{
	297	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
	298	if (likely(copied == bytes))
	299	return true;
	300	iov_iter_revert(i, copied);
	301	return false;
	302	}
d05f4435 SG	303	size_t hash_and_copy_to_iter(const void addr, size_t bytes, void hashp,
d05f4435 SG	304	struct iov_iter *i);
b42b15fd	305
bfdc5970 CH	306	struct iovec iovec_from_user(const struct iovec __user uvector,
	307	unsigned long nr_segs, unsigned long fast_segs,
	308	struct iovec *fast_iov, bool compat);
	309	ssize_t import_iovec(int type, const struct iovec __user *uvec,
	310	unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
	311	struct iov_iter *i);
	312	ssize_t __import_iovec(int type, const struct iovec __user *uvec,
	313	unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
	314	struct iov_iter *i, bool compat);
bc917be8 AV	315	int import_single_range(int type, void __user *buf, size_t len,
	316	struct iovec iov, struct iov_iter i);
	317
812ed032	318	#endif