[linux-block.git] / include / linux / uio.h

/*
 *	Berkeley style UIO structures	-	Alan Cox 1994.
 *
 *		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; either version
 *		2 of the License, or (at your option) any later version.
 */
#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_IOVEC = 0,
	ITER_KVEC = 2,
	ITER_BVEC = 4,
	ITER_PIPE = 8,
};

struct iov_iter {
	unsigned int type;
	size_t iov_offset;
	size_t count;
	union {
		const struct iovec *iov;
		const struct kvec *kvec;
		const struct bio_vec *bvec;
		struct pipe_inode_info *pipe;
	};
	union {
		unsigned long nr_segs;
		struct {
			int idx;
			int start_idx;
		};
	};
};

static inline enum iter_type iov_iter_type(const struct iov_iter *i)
{
	return i->type & ~(READ | WRITE);
}

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 unsigned char iov_iter_rw(const struct iov_iter *i)
{
	return i->type & (READ | WRITE);
}

/*
 * 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),
	};
}

#define iov_for_each(iov, iter, start)				\
	if (iov_iter_type(start) == ITER_IOVEC ||		\
	    iov_iter_type(start) == ITER_KVEC)			\
	for (iter = (start);					\
	     (iter).count &&					\
	     ((iov = iov_iter_iovec(&(iter))), 1);		\
	     iov_iter_advance(&(iter), (iov).iov_len))

size_t iov_iter_copy_from_user_atomic(struct page *page,
		struct iov_iter *i, unsigned long offset, size_t bytes);
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(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);
bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
bool _copy_from_iter_full_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)
{
	if (unlikely(!check_copy_size(addr, bytes, false)))
		return false;
	else
		return _copy_from_iter_full(addr, bytes, i);
}

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)
{
	if (unlikely(!check_copy_size(addr, bytes, false)))
		return false;
	else
		return _copy_from_iter_full_nocache(addr, bytes, i);
}

#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_UACCESS_MCSAFE
size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i);
#else
#define _copy_to_iter_mcsafe _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_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)
{
	if (unlikely(!check_copy_size(addr, bytes, true)))
		return 0;
	else
		return _copy_to_iter_mcsafe(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);
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);

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

int import_iovec(int type, const struct iovec __user * uvector,
		 unsigned nr_segs, unsigned fast_segs,
		 struct iovec **iov, struct iov_iter *i);

#ifdef CONFIG_COMPAT
struct compat_iovec;
int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
		 unsigned nr_segs, unsigned fast_segs,
		 struct iovec **iov, struct iov_iter *i);
#endif

int import_single_range(int type, void __user *buf, size_t len,
		 struct iovec *iov, struct iov_iter *i);

int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
			    int (*f)(struct kvec *vec, void *context),
			    void *context);

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Berkeley style UIO structures - Alan Cox 1994.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*/
607ca46e DH	9	#ifndef __LINUX_UIO_H
607ca46e DH	10	#define __LINUX_UIO_H
1da177e4	11
92236878	12	#include <linux/kernel.h>
aa28de27	13	#include <linux/thread_info.h>
607ca46e	14	#include <uapi/linux/uio.h>
1da177e4	15
92236878	16	struct page;
241699cd	17	struct pipe_inode_info;
812ed032 JS	18
	19	struct kvec {
	20	void iov_base; / and that should never hold a userland pointer */
	21	size_t iov_len;
	22	};
	23
00e23707	24	enum iter_type {
62a8067a AV	25	ITER_IOVEC = 0,
	26	ITER_KVEC = 2,
	27	ITER_BVEC = 4,
241699cd	28	ITER_PIPE = 8,
62a8067a AV	29	};
62a8067a AV	30
92236878	31	struct iov_iter {
aa563d7b	32	unsigned int type;
92236878 KO	33	size_t iov_offset;
92236878 KO	34	size_t count;
62a8067a AV	35	union {
62a8067a AV	36	const struct iovec *iov;
a280455f	37	const struct kvec *kvec;
62a8067a	38	const struct bio_vec *bvec;
241699cd AV	39	struct pipe_inode_info *pipe;
	40	};
	41	union {
	42	unsigned long nr_segs;
27c0e374 AV	43	struct {
	44	int idx;
	45	int start_idx;
	46	};
62a8067a	47	};
92236878 KO	48	};
92236878 KO	49
00e23707 DH	50	static inline enum iter_type iov_iter_type(const struct iov_iter *i)
	51	{
	52	return i->type & ~(READ \| WRITE);
	53	}
	54
	55	static inline bool iter_is_iovec(const struct iov_iter *i)
	56	{
	57	return iov_iter_type(i) == ITER_IOVEC;
	58	}
	59
	60	static inline bool iov_iter_is_kvec(const struct iov_iter *i)
	61	{
	62	return iov_iter_type(i) == ITER_KVEC;
	63	}
	64
	65	static inline bool iov_iter_is_bvec(const struct iov_iter *i)
	66	{
	67	return iov_iter_type(i) == ITER_BVEC;
	68	}
	69
	70	static inline bool iov_iter_is_pipe(const struct iov_iter *i)
	71	{
	72	return iov_iter_type(i) == ITER_PIPE;
	73	}
	74
	75	static inline unsigned char iov_iter_rw(const struct iov_iter *i)
	76	{
	77	return i->type & (READ \| WRITE);
	78	}
	79
1da177e4 LT	80	/*
	81	* Total number of bytes covered by an iovec.
	82	*
	83	* NOTE that it is not safe to use this function until all the iovec's
	84	* segment lengths have been validated. Because the individual lengths can
	85	* overflow a size_t when added together.
	86	*/
	87	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	88	{
	89	unsigned long seg;
	90	size_t ret = 0;
	91
	92	for (seg = 0; seg < nr_segs; seg++)
	93	ret += iov[seg].iov_len;
	94	return ret;
	95	}
	96
92236878 KO	97	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	98	{
	99	return (struct iovec) {
	100	.iov_base = iter->iov->iov_base + iter->iov_offset,
	101	.iov_len = min(iter->count,
	102	iter->iov->iov_len - iter->iov_offset),
	103	};
	104	}
	105
	106	#define iov_for_each(iov, iter, start) \
00e23707 DH	107	if (iov_iter_type(start) == ITER_IOVEC \|\| \
00e23707 DH	108	iov_iter_type(start) == ITER_KVEC) \
92236878 KO	109	for (iter = (start); \
	110	(iter).count && \
	111	((iov = iov_iter_iovec(&(iter))), 1); \
	112	iov_iter_advance(&(iter), (iov).iov_len))
	113
92236878 KO	114	size_t iov_iter_copy_from_user_atomic(struct page *page,
92236878 KO	115	struct iov_iter *i, unsigned long offset, size_t bytes);
92236878	116	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	117	void iov_iter_revert(struct iov_iter *i, size_t bytes);
92236878 KO	118	int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
92236878 KO	119	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	120	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	121	struct iov_iter *i);
f0d1bec9 AV	122	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	123	struct iov_iter *i);
aa28de27 AV	124
	125	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	126	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
	127	bool _copy_from_iter_full(void addr, size_t bytes, struct iov_iter i);
	128	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
	129	bool _copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i);
	130
	131	static __always_inline __must_check
	132	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	133	{
	134	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	135	return 0;
aa28de27 AV	136	else
	137	return _copy_to_iter(addr, bytes, i);
	138	}
	139
	140	static __always_inline __must_check
	141	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	142	{
	143	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	144	return 0;
aa28de27 AV	145	else
	146	return _copy_from_iter(addr, bytes, i);
	147	}
	148
	149	static __always_inline __must_check
	150	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	151	{
	152	if (unlikely(!check_copy_size(addr, bytes, false)))
	153	return false;
	154	else
	155	return _copy_from_iter_full(addr, bytes, i);
	156	}
	157
	158	static __always_inline __must_check
	159	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	160	{
	161	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	162	return 0;
aa28de27 AV	163	else
	164	return _copy_from_iter_nocache(addr, bytes, i);
	165	}
	166
	167	static __always_inline __must_check
	168	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	169	{
	170	if (unlikely(!check_copy_size(addr, bytes, false)))
	171	return false;
	172	else
	173	return _copy_from_iter_full_nocache(addr, bytes, i);
	174	}
	175
0aed55af DW	176	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	177	/*
	178	* Note, users like pmem that depend on the stricter semantics of
	179	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	180	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	181	* destination is flushed from the cache on return.
	182	*/
6a37e940	183	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	184	#else
6a37e940 LT	185	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	186	#endif
	187
8780356e	188	#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
522239b4	189	size_t _copy_to_iter_mcsafe(const void addr, size_t bytes, struct iov_iter i);
8780356e DW	190	#else
	191	#define _copy_to_iter_mcsafe _copy_to_iter
	192	#endif
	193
6a37e940 LT	194	static __always_inline __must_check
6a37e940 LT	195	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	196	{
6a37e940	197	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	198	return 0;
6a37e940 LT	199	else
6a37e940 LT	200	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	201	}
6a37e940	202
8780356e DW	203	static __always_inline __must_check
	204	size_t copy_to_iter_mcsafe(void addr, size_t bytes, struct iov_iter i)
	205	{
dfb06cba	206	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	207	return 0;
	208	else
	209	return _copy_to_iter_mcsafe(addr, bytes, i);
	210	}
	211
c35e0248	212	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	213	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	214	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
aa563d7b	215	void iov_iter_init(struct iov_iter i, unsigned int direction, const struct iovec iov,
71d8e532	216	unsigned long nr_segs, size_t count);
aa563d7b	217	void iov_iter_kvec(struct iov_iter i, unsigned int direction, const struct kvec kvec,
05afcb77	218	unsigned long nr_segs, size_t count);
aa563d7b	219	void iov_iter_bvec(struct iov_iter i, unsigned int direction, const struct bio_vec bvec,
abb78f87	220	unsigned long nr_segs, size_t count);
aa563d7b	221	void iov_iter_pipe(struct iov_iter i, unsigned int direction, struct pipe_inode_info pipe,
241699cd	222	size_t count);
7b2c99d1	223	ssize_t iov_iter_get_pages(struct iov_iter i, struct page *pages,
2c80929c	224	size_t maxsize, unsigned maxpages, size_t *start);
91f79c43 AV	225	ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
91f79c43 AV	226	size_t maxsize, size_t *start);
f67da30c	227	int iov_iter_npages(const struct iov_iter *i, int maxpages);
92236878	228
4b8164b9 AV	229	const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);
4b8164b9 AV	230
b57332b4	231	static inline size_t iov_iter_count(const struct iov_iter *i)
92236878 KO	232	{
	233	return i->count;
	234	}
	235
0b86dbf6 AV	236	/*
	237	* Cap the iov_iter by given limit; note that the second argument is
	238	* not the new size - it's upper limit for such. Passing it a value
	239	* greater than the amount of data in iov_iter is fine - it'll just do
	240	* nothing in that case.
	241	*/
	242	static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
0c949334	243	{
0b86dbf6 AV	244	/*
	245	* count doesn't have to fit in size_t - comparison extends both
	246	* operands to u64 here and any value that would be truncated by
	247	* conversion in assignement is by definition greater than all
	248	* values of size_t, including old i->count.
	249	*/
0c949334 AV	250	if (i->count > count)
	251	i->count = count;
	252	}
	253
b42b15fd AV	254	/*
	255	* reexpand a previously truncated iterator; count must be no more than how much
	256	* we had shrunk it.
	257	*/
	258	static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
	259	{
	260	i->count = count;
	261	}
36f7a8a4	262	size_t csum_and_copy_to_iter(const void addr, size_t bytes, __wsum csum, struct iov_iter *i);
a604ec7e	263	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
cbbd26b8	264	bool csum_and_copy_from_iter_full(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
b42b15fd	265
bc917be8 AV	266	int import_iovec(int type, const struct iovec __user * uvector,
	267	unsigned nr_segs, unsigned fast_segs,
	268	struct iovec *iov, struct iov_iter i);
	269
	270	#ifdef CONFIG_COMPAT
	271	struct compat_iovec;
	272	int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
	273	unsigned nr_segs, unsigned fast_segs,
	274	struct iovec *iov, struct iov_iter i);
	275	#endif
	276
	277	int import_single_range(int type, void __user *buf, size_t len,
	278	struct iovec iov, struct iov_iter i);
	279
09cf698a AV	280	int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
	281	int (f)(struct kvec vec, void *context),
	282	void *context);
	283
812ed032	284	#endif