[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 <crypto/hash.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,
	ITER_DISCARD = 16,
};

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

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);
void iov_iter_discard(struct iov_iter *i, unsigned int direction, 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, void *csump, 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);
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
		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>
d05f4435	14	#include <crypto/hash.h>
607ca46e	15	#include <uapi/linux/uio.h>
1da177e4	16
92236878	17	struct page;
241699cd	18	struct pipe_inode_info;
812ed032 JS	19
	20	struct kvec {
	21	void iov_base; / and that should never hold a userland pointer */
	22	size_t iov_len;
	23	};
	24
00e23707	25	enum iter_type {
62a8067a AV	26	ITER_IOVEC = 0,
	27	ITER_KVEC = 2,
	28	ITER_BVEC = 4,
241699cd	29	ITER_PIPE = 8,
9ea9ce04	30	ITER_DISCARD = 16,
62a8067a AV	31	};
62a8067a AV	32
92236878	33	struct iov_iter {
aa563d7b	34	unsigned int type;
92236878 KO	35	size_t iov_offset;
92236878 KO	36	size_t count;
62a8067a AV	37	union {
62a8067a AV	38	const struct iovec *iov;
a280455f	39	const struct kvec *kvec;
62a8067a	40	const struct bio_vec *bvec;
241699cd AV	41	struct pipe_inode_info *pipe;
	42	};
	43	union {
	44	unsigned long nr_segs;
27c0e374 AV	45	struct {
	46	int idx;
	47	int start_idx;
	48	};
62a8067a	49	};
92236878 KO	50	};
92236878 KO	51
00e23707 DH	52	static inline enum iter_type iov_iter_type(const struct iov_iter *i)
	53	{
	54	return i->type & ~(READ \| WRITE);
	55	}
	56
	57	static inline bool iter_is_iovec(const struct iov_iter *i)
	58	{
	59	return iov_iter_type(i) == ITER_IOVEC;
	60	}
	61
	62	static inline bool iov_iter_is_kvec(const struct iov_iter *i)
	63	{
	64	return iov_iter_type(i) == ITER_KVEC;
	65	}
	66
	67	static inline bool iov_iter_is_bvec(const struct iov_iter *i)
	68	{
	69	return iov_iter_type(i) == ITER_BVEC;
	70	}
	71
	72	static inline bool iov_iter_is_pipe(const struct iov_iter *i)
	73	{
	74	return iov_iter_type(i) == ITER_PIPE;
	75	}
	76
9ea9ce04 DH	77	static inline bool iov_iter_is_discard(const struct iov_iter *i)
	78	{
	79	return iov_iter_type(i) == ITER_DISCARD;
	80	}
	81
00e23707 DH	82	static inline unsigned char iov_iter_rw(const struct iov_iter *i)
	83	{
	84	return i->type & (READ \| WRITE);
	85	}
	86
1da177e4 LT	87	/*
	88	* Total number of bytes covered by an iovec.
	89	*
	90	* NOTE that it is not safe to use this function until all the iovec's
	91	* segment lengths have been validated. Because the individual lengths can
	92	* overflow a size_t when added together.
	93	*/
	94	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	95	{
	96	unsigned long seg;
	97	size_t ret = 0;
	98
	99	for (seg = 0; seg < nr_segs; seg++)
	100	ret += iov[seg].iov_len;
	101	return ret;
	102	}
	103
92236878 KO	104	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	105	{
	106	return (struct iovec) {
	107	.iov_base = iter->iov->iov_base + iter->iov_offset,
	108	.iov_len = min(iter->count,
	109	iter->iov->iov_len - iter->iov_offset),
	110	};
	111	}
	112
	113	#define iov_for_each(iov, iter, start) \
00e23707 DH	114	if (iov_iter_type(start) == ITER_IOVEC \|\| \
00e23707 DH	115	iov_iter_type(start) == ITER_KVEC) \
92236878 KO	116	for (iter = (start); \
	117	(iter).count && \
	118	((iov = iov_iter_iovec(&(iter))), 1); \
	119	iov_iter_advance(&(iter), (iov).iov_len))
	120
92236878 KO	121	size_t iov_iter_copy_from_user_atomic(struct page *page,
92236878 KO	122	struct iov_iter *i, unsigned long offset, size_t bytes);
92236878	123	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	124	void iov_iter_revert(struct iov_iter *i, size_t bytes);
92236878 KO	125	int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
92236878 KO	126	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	127	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	128	struct iov_iter *i);
f0d1bec9 AV	129	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	130	struct iov_iter *i);
aa28de27 AV	131
	132	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	133	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
	134	bool _copy_from_iter_full(void addr, size_t bytes, struct iov_iter i);
	135	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
	136	bool _copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i);
	137
	138	static __always_inline __must_check
	139	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	140	{
	141	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	142	return 0;
aa28de27 AV	143	else
	144	return _copy_to_iter(addr, bytes, i);
	145	}
	146
	147	static __always_inline __must_check
	148	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	149	{
	150	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	151	return 0;
aa28de27 AV	152	else
	153	return _copy_from_iter(addr, bytes, i);
	154	}
	155
	156	static __always_inline __must_check
	157	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	158	{
	159	if (unlikely(!check_copy_size(addr, bytes, false)))
	160	return false;
	161	else
	162	return _copy_from_iter_full(addr, bytes, i);
	163	}
	164
	165	static __always_inline __must_check
	166	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	167	{
	168	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	169	return 0;
aa28de27 AV	170	else
	171	return _copy_from_iter_nocache(addr, bytes, i);
	172	}
	173
	174	static __always_inline __must_check
	175	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	176	{
	177	if (unlikely(!check_copy_size(addr, bytes, false)))
	178	return false;
	179	else
	180	return _copy_from_iter_full_nocache(addr, bytes, i);
	181	}
	182
0aed55af DW	183	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	184	/*
	185	* Note, users like pmem that depend on the stricter semantics of
	186	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	187	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	188	* destination is flushed from the cache on return.
	189	*/
6a37e940	190	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	191	#else
6a37e940 LT	192	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	193	#endif
	194
8780356e	195	#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
522239b4	196	size_t _copy_to_iter_mcsafe(const void addr, size_t bytes, struct iov_iter i);
8780356e DW	197	#else
	198	#define _copy_to_iter_mcsafe _copy_to_iter
	199	#endif
	200
6a37e940 LT	201	static __always_inline __must_check
6a37e940 LT	202	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	203	{
6a37e940	204	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	205	return 0;
6a37e940 LT	206	else
6a37e940 LT	207	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	208	}
6a37e940	209
8780356e DW	210	static __always_inline __must_check
	211	size_t copy_to_iter_mcsafe(void addr, size_t bytes, struct iov_iter i)
	212	{
dfb06cba	213	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	214	return 0;
	215	else
	216	return _copy_to_iter_mcsafe(addr, bytes, i);
	217	}
	218
c35e0248	219	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	220	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	221	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
aa563d7b	222	void iov_iter_init(struct iov_iter i, unsigned int direction, const struct iovec iov,
71d8e532	223	unsigned long nr_segs, size_t count);
aa563d7b	224	void iov_iter_kvec(struct iov_iter i, unsigned int direction, const struct kvec kvec,
05afcb77	225	unsigned long nr_segs, size_t count);
aa563d7b	226	void iov_iter_bvec(struct iov_iter i, unsigned int direction, const struct bio_vec bvec,
abb78f87	227	unsigned long nr_segs, size_t count);
aa563d7b	228	void iov_iter_pipe(struct iov_iter i, unsigned int direction, struct pipe_inode_info pipe,
241699cd	229	size_t count);
9ea9ce04	230	void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
7b2c99d1	231	ssize_t iov_iter_get_pages(struct iov_iter i, struct page *pages,
2c80929c	232	size_t maxsize, unsigned maxpages, size_t *start);
91f79c43 AV	233	ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
91f79c43 AV	234	size_t maxsize, size_t *start);
f67da30c	235	int iov_iter_npages(const struct iov_iter *i, int maxpages);
92236878	236
4b8164b9 AV	237	const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);
4b8164b9 AV	238
b57332b4	239	static inline size_t iov_iter_count(const struct iov_iter *i)
92236878 KO	240	{
	241	return i->count;
	242	}
	243
0b86dbf6 AV	244	/*
	245	* Cap the iov_iter by given limit; note that the second argument is
	246	* not the new size - it's upper limit for such. Passing it a value
	247	* greater than the amount of data in iov_iter is fine - it'll just do
	248	* nothing in that case.
	249	*/
	250	static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
0c949334	251	{
0b86dbf6 AV	252	/*
	253	* count doesn't have to fit in size_t - comparison extends both
	254	* operands to u64 here and any value that would be truncated by
	255	* conversion in assignement is by definition greater than all
	256	* values of size_t, including old i->count.
	257	*/
0c949334 AV	258	if (i->count > count)
	259	i->count = count;
	260	}
	261
b42b15fd AV	262	/*
	263	* reexpand a previously truncated iterator; count must be no more than how much
	264	* we had shrunk it.
	265	*/
	266	static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
	267	{
	268	i->count = count;
	269	}
cb002d07	270	size_t csum_and_copy_to_iter(const void addr, size_t bytes, void csump, struct iov_iter *i);
a604ec7e	271	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
cbbd26b8	272	bool csum_and_copy_from_iter_full(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
d05f4435 SG	273	size_t hash_and_copy_to_iter(const void addr, size_t bytes, void hashp,
d05f4435 SG	274	struct iov_iter *i);
b42b15fd	275
bc917be8 AV	276	int import_iovec(int type, const struct iovec __user * uvector,
	277	unsigned nr_segs, unsigned fast_segs,
	278	struct iovec *iov, struct iov_iter i);
	279
	280	#ifdef CONFIG_COMPAT
	281	struct compat_iovec;
	282	int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
	283	unsigned nr_segs, unsigned fast_segs,
	284	struct iovec *iov, struct iov_iter i);
	285	#endif
	286
	287	int import_single_range(int type, void __user *buf, size_t len,
	288	struct iovec iov, struct iov_iter i);
	289
09cf698a AV	290	int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
	291	int (f)(struct kvec vec, void *context),
	292	void *context);
	293
812ed032	294	#endif