[mirror_ubuntu-eoan-kernel.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,
	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, __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,
9ea9ce04	29	ITER_DISCARD = 16,
62a8067a AV	30	};
62a8067a AV	31
92236878	32	struct iov_iter {
aa563d7b	33	unsigned int type;
92236878 KO	34	size_t iov_offset;
92236878 KO	35	size_t count;
62a8067a AV	36	union {
62a8067a AV	37	const struct iovec *iov;
a280455f	38	const struct kvec *kvec;
62a8067a	39	const struct bio_vec *bvec;
241699cd AV	40	struct pipe_inode_info *pipe;
	41	};
	42	union {
	43	unsigned long nr_segs;
27c0e374 AV	44	struct {
	45	int idx;
	46	int start_idx;
	47	};
62a8067a	48	};
92236878 KO	49	};
92236878 KO	50
00e23707 DH	51	static inline enum iter_type iov_iter_type(const struct iov_iter *i)
	52	{
	53	return i->type & ~(READ \| WRITE);
	54	}
	55
	56	static inline bool iter_is_iovec(const struct iov_iter *i)
	57	{
	58	return iov_iter_type(i) == ITER_IOVEC;
	59	}
	60
	61	static inline bool iov_iter_is_kvec(const struct iov_iter *i)
	62	{
	63	return iov_iter_type(i) == ITER_KVEC;
	64	}
	65
	66	static inline bool iov_iter_is_bvec(const struct iov_iter *i)
	67	{
	68	return iov_iter_type(i) == ITER_BVEC;
	69	}
	70
	71	static inline bool iov_iter_is_pipe(const struct iov_iter *i)
	72	{
	73	return iov_iter_type(i) == ITER_PIPE;
	74	}
	75
9ea9ce04 DH	76	static inline bool iov_iter_is_discard(const struct iov_iter *i)
	77	{
	78	return iov_iter_type(i) == ITER_DISCARD;
	79	}
	80
00e23707 DH	81	static inline unsigned char iov_iter_rw(const struct iov_iter *i)
	82	{
	83	return i->type & (READ \| WRITE);
	84	}
	85
1da177e4 LT	86	/*
	87	* Total number of bytes covered by an iovec.
	88	*
	89	* NOTE that it is not safe to use this function until all the iovec's
	90	* segment lengths have been validated. Because the individual lengths can
	91	* overflow a size_t when added together.
	92	*/
	93	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	94	{
	95	unsigned long seg;
	96	size_t ret = 0;
	97
	98	for (seg = 0; seg < nr_segs; seg++)
	99	ret += iov[seg].iov_len;
	100	return ret;
	101	}
	102
92236878 KO	103	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	104	{
	105	return (struct iovec) {
	106	.iov_base = iter->iov->iov_base + iter->iov_offset,
	107	.iov_len = min(iter->count,
	108	iter->iov->iov_len - iter->iov_offset),
	109	};
	110	}
	111
	112	#define iov_for_each(iov, iter, start) \
00e23707 DH	113	if (iov_iter_type(start) == ITER_IOVEC \|\| \
00e23707 DH	114	iov_iter_type(start) == ITER_KVEC) \
92236878 KO	115	for (iter = (start); \
	116	(iter).count && \
	117	((iov = iov_iter_iovec(&(iter))), 1); \
	118	iov_iter_advance(&(iter), (iov).iov_len))
	119
92236878 KO	120	size_t iov_iter_copy_from_user_atomic(struct page *page,
92236878 KO	121	struct iov_iter *i, unsigned long offset, size_t bytes);
92236878	122	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	123	void iov_iter_revert(struct iov_iter *i, size_t bytes);
92236878 KO	124	int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
92236878 KO	125	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	126	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	127	struct iov_iter *i);
f0d1bec9 AV	128	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	129	struct iov_iter *i);
aa28de27 AV	130
	131	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	132	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
	133	bool _copy_from_iter_full(void addr, size_t bytes, struct iov_iter i);
	134	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
	135	bool _copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i);
	136
	137	static __always_inline __must_check
	138	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	139	{
	140	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	141	return 0;
aa28de27 AV	142	else
	143	return _copy_to_iter(addr, bytes, i);
	144	}
	145
	146	static __always_inline __must_check
	147	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	148	{
	149	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	150	return 0;
aa28de27 AV	151	else
	152	return _copy_from_iter(addr, bytes, i);
	153	}
	154
	155	static __always_inline __must_check
	156	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	157	{
	158	if (unlikely(!check_copy_size(addr, bytes, false)))
	159	return false;
	160	else
	161	return _copy_from_iter_full(addr, bytes, i);
	162	}
	163
	164	static __always_inline __must_check
	165	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	166	{
	167	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	168	return 0;
aa28de27 AV	169	else
	170	return _copy_from_iter_nocache(addr, bytes, i);
	171	}
	172
	173	static __always_inline __must_check
	174	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	175	{
	176	if (unlikely(!check_copy_size(addr, bytes, false)))
	177	return false;
	178	else
	179	return _copy_from_iter_full_nocache(addr, bytes, i);
	180	}
	181
0aed55af DW	182	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	183	/*
	184	* Note, users like pmem that depend on the stricter semantics of
	185	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	186	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	187	* destination is flushed from the cache on return.
	188	*/
6a37e940	189	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	190	#else
6a37e940 LT	191	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	192	#endif
	193
8780356e	194	#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
522239b4	195	size_t _copy_to_iter_mcsafe(const void addr, size_t bytes, struct iov_iter i);
8780356e DW	196	#else
	197	#define _copy_to_iter_mcsafe _copy_to_iter
	198	#endif
	199
6a37e940 LT	200	static __always_inline __must_check
6a37e940 LT	201	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	202	{
6a37e940	203	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	204	return 0;
6a37e940 LT	205	else
6a37e940 LT	206	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	207	}
6a37e940	208
8780356e DW	209	static __always_inline __must_check
	210	size_t copy_to_iter_mcsafe(void addr, size_t bytes, struct iov_iter i)
	211	{
dfb06cba	212	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	213	return 0;
	214	else
	215	return _copy_to_iter_mcsafe(addr, bytes, i);
	216	}
	217
c35e0248	218	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	219	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	220	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
aa563d7b	221	void iov_iter_init(struct iov_iter i, unsigned int direction, const struct iovec iov,
71d8e532	222	unsigned long nr_segs, size_t count);
aa563d7b	223	void iov_iter_kvec(struct iov_iter i, unsigned int direction, const struct kvec kvec,
05afcb77	224	unsigned long nr_segs, size_t count);
aa563d7b	225	void iov_iter_bvec(struct iov_iter i, unsigned int direction, const struct bio_vec bvec,
abb78f87	226	unsigned long nr_segs, size_t count);
aa563d7b	227	void iov_iter_pipe(struct iov_iter i, unsigned int direction, struct pipe_inode_info pipe,
241699cd	228	size_t count);
9ea9ce04	229	void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
7b2c99d1	230	ssize_t iov_iter_get_pages(struct iov_iter i, struct page *pages,
2c80929c	231	size_t maxsize, unsigned maxpages, size_t *start);
91f79c43 AV	232	ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
91f79c43 AV	233	size_t maxsize, size_t *start);
f67da30c	234	int iov_iter_npages(const struct iov_iter *i, int maxpages);
92236878	235
4b8164b9 AV	236	const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);
4b8164b9 AV	237
b57332b4	238	static inline size_t iov_iter_count(const struct iov_iter *i)
92236878 KO	239	{
	240	return i->count;
	241	}
	242
0b86dbf6 AV	243	/*
	244	* Cap the iov_iter by given limit; note that the second argument is
	245	* not the new size - it's upper limit for such. Passing it a value
	246	* greater than the amount of data in iov_iter is fine - it'll just do
	247	* nothing in that case.
	248	*/
	249	static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
0c949334	250	{
0b86dbf6 AV	251	/*
	252	* count doesn't have to fit in size_t - comparison extends both
	253	* operands to u64 here and any value that would be truncated by
	254	* conversion in assignement is by definition greater than all
	255	* values of size_t, including old i->count.
	256	*/
0c949334 AV	257	if (i->count > count)
	258	i->count = count;
	259	}
	260
b42b15fd AV	261	/*
	262	* reexpand a previously truncated iterator; count must be no more than how much
	263	* we had shrunk it.
	264	*/
	265	static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
	266	{
	267	i->count = count;
	268	}
36f7a8a4	269	size_t csum_and_copy_to_iter(const void addr, size_t bytes, __wsum csum, struct iov_iter *i);
a604ec7e	270	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
cbbd26b8	271	bool csum_and_copy_from_iter_full(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
b42b15fd	272
bc917be8 AV	273	int import_iovec(int type, const struct iovec __user * uvector,
	274	unsigned nr_segs, unsigned fast_segs,
	275	struct iovec *iov, struct iov_iter i);
	276
	277	#ifdef CONFIG_COMPAT
	278	struct compat_iovec;
	279	int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
	280	unsigned nr_segs, unsigned fast_segs,
	281	struct iovec *iov, struct iov_iter i);
	282	#endif
	283
	284	int import_single_range(int type, void __user *buf, size_t len,
	285	struct iovec iov, struct iov_iter i);
	286
09cf698a AV	287	int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
	288	int (f)(struct kvec vec, void *context),
	289	void *context);
	290
812ed032	291	#endif