[mirror_ubuntu-focal-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_IOVEC = 0,
	ITER_KVEC = 2,
	ITER_BVEC = 4,
	ITER_PIPE = 8,
};

struct iov_iter {
	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;
		};
	};
};

/*
 * 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 (!((start).type & (ITER_BVEC | ITER_PIPE)))		\
	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, int direction, const struct iovec *iov,
			unsigned long nr_segs, size_t count);
void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
			unsigned long nr_segs, size_t count);
void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
			unsigned long nr_segs, size_t count);
void iov_iter_pipe(struct iov_iter *i, 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;
}

static inline bool iter_is_iovec(const struct iov_iter *i)
{
	return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
}

/*
 * Get one of READ or WRITE out of iter->type without any other flags OR'd in
 * with it.
 *
 * The ?: is just for type safety.
 */
#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE))

/*
 * 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
62a8067a AV	24	enum {
	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 {
71d8e532	32	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
1da177e4 LT	50	/*
	51	* Total number of bytes covered by an iovec.
	52	*
	53	* NOTE that it is not safe to use this function until all the iovec's
	54	* segment lengths have been validated. Because the individual lengths can
	55	* overflow a size_t when added together.
	56	*/
	57	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	58	{
	59	unsigned long seg;
	60	size_t ret = 0;
	61
	62	for (seg = 0; seg < nr_segs; seg++)
	63	ret += iov[seg].iov_len;
	64	return ret;
	65	}
	66
92236878 KO	67	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	68	{
	69	return (struct iovec) {
	70	.iov_base = iter->iov->iov_base + iter->iov_offset,
	71	.iov_len = min(iter->count,
	72	iter->iov->iov_len - iter->iov_offset),
	73	};
	74	}
	75
	76	#define iov_for_each(iov, iter, start) \
241699cd	77	if (!((start).type & (ITER_BVEC \| ITER_PIPE))) \
92236878 KO	78	for (iter = (start); \
	79	(iter).count && \
	80	((iov = iov_iter_iovec(&(iter))), 1); \
	81	iov_iter_advance(&(iter), (iov).iov_len))
	82
92236878 KO	83	size_t iov_iter_copy_from_user_atomic(struct page *page,
92236878 KO	84	struct iov_iter *i, unsigned long offset, size_t bytes);
92236878	85	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	86	void iov_iter_revert(struct iov_iter *i, size_t bytes);
92236878 KO	87	int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
92236878 KO	88	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	89	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	90	struct iov_iter *i);
f0d1bec9 AV	91	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	92	struct iov_iter *i);
aa28de27 AV	93
	94	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	95	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
	96	bool _copy_from_iter_full(void addr, size_t bytes, struct iov_iter i);
	97	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
	98	bool _copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i);
	99
	100	static __always_inline __must_check
	101	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	102	{
	103	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	104	return 0;
aa28de27 AV	105	else
	106	return _copy_to_iter(addr, bytes, i);
	107	}
	108
	109	static __always_inline __must_check
	110	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	111	{
	112	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	113	return 0;
aa28de27 AV	114	else
	115	return _copy_from_iter(addr, bytes, i);
	116	}
	117
	118	static __always_inline __must_check
	119	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	120	{
	121	if (unlikely(!check_copy_size(addr, bytes, false)))
	122	return false;
	123	else
	124	return _copy_from_iter_full(addr, bytes, i);
	125	}
	126
	127	static __always_inline __must_check
	128	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	129	{
	130	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	131	return 0;
aa28de27 AV	132	else
	133	return _copy_from_iter_nocache(addr, bytes, i);
	134	}
	135
	136	static __always_inline __must_check
	137	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	138	{
	139	if (unlikely(!check_copy_size(addr, bytes, false)))
	140	return false;
	141	else
	142	return _copy_from_iter_full_nocache(addr, bytes, i);
	143	}
	144
0aed55af DW	145	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	146	/*
	147	* Note, users like pmem that depend on the stricter semantics of
	148	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	149	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	150	* destination is flushed from the cache on return.
	151	*/
6a37e940	152	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	153	#else
6a37e940 LT	154	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	155	#endif
	156
8780356e	157	#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
522239b4	158	size_t _copy_to_iter_mcsafe(const void addr, size_t bytes, struct iov_iter i);
8780356e DW	159	#else
	160	#define _copy_to_iter_mcsafe _copy_to_iter
	161	#endif
	162
6a37e940 LT	163	static __always_inline __must_check
6a37e940 LT	164	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	165	{
6a37e940	166	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	167	return 0;
6a37e940 LT	168	else
6a37e940 LT	169	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	170	}
6a37e940	171
8780356e DW	172	static __always_inline __must_check
	173	size_t copy_to_iter_mcsafe(void addr, size_t bytes, struct iov_iter i)
	174	{
dfb06cba	175	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	176	return 0;
	177	else
	178	return _copy_to_iter_mcsafe(addr, bytes, i);
	179	}
	180
c35e0248	181	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	182	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	183	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
71d8e532 AV	184	void iov_iter_init(struct iov_iter i, int direction, const struct iovec iov,
71d8e532 AV	185	unsigned long nr_segs, size_t count);
05afcb77 AV	186	void iov_iter_kvec(struct iov_iter i, int direction, const struct kvec kvec,
	187	unsigned long nr_segs, size_t count);
	188	void iov_iter_bvec(struct iov_iter i, int direction, const struct bio_vec bvec,
abb78f87	189	unsigned long nr_segs, size_t count);
241699cd AV	190	void iov_iter_pipe(struct iov_iter i, int direction, struct pipe_inode_info pipe,
241699cd AV	191	size_t count);
7b2c99d1	192	ssize_t iov_iter_get_pages(struct iov_iter i, struct page *pages,
2c80929c	193	size_t maxsize, unsigned maxpages, size_t *start);
91f79c43 AV	194	ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
91f79c43 AV	195	size_t maxsize, size_t *start);
f67da30c	196	int iov_iter_npages(const struct iov_iter *i, int maxpages);
92236878	197
4b8164b9 AV	198	const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);
4b8164b9 AV	199
b57332b4	200	static inline size_t iov_iter_count(const struct iov_iter *i)
92236878 KO	201	{
	202	return i->count;
	203	}
	204
b57332b4	205	static inline bool iter_is_iovec(const struct iov_iter *i)
777eda2c	206	{
241699cd	207	return !(i->type & (ITER_BVEC \| ITER_KVEC \| ITER_PIPE));
777eda2c AV	208	}
777eda2c AV	209
bd8e0ff9 OS	210	/*
	211	* Get one of READ or WRITE out of iter->type without any other flags OR'd in
	212	* with it.
	213	*
	214	* The ?: is just for type safety.
	215	*/
d3849953	216	#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ \| WRITE))
bd8e0ff9	217
0b86dbf6 AV	218	/*
	219	* Cap the iov_iter by given limit; note that the second argument is
	220	* not the new size - it's upper limit for such. Passing it a value
	221	* greater than the amount of data in iov_iter is fine - it'll just do
	222	* nothing in that case.
	223	*/
	224	static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
0c949334	225	{
0b86dbf6 AV	226	/*
	227	* count doesn't have to fit in size_t - comparison extends both
	228	* operands to u64 here and any value that would be truncated by
	229	* conversion in assignement is by definition greater than all
	230	* values of size_t, including old i->count.
	231	*/
0c949334 AV	232	if (i->count > count)
	233	i->count = count;
	234	}
	235
b42b15fd AV	236	/*
	237	* reexpand a previously truncated iterator; count must be no more than how much
	238	* we had shrunk it.
	239	*/
	240	static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
	241	{
	242	i->count = count;
	243	}
36f7a8a4	244	size_t csum_and_copy_to_iter(const void addr, size_t bytes, __wsum csum, struct iov_iter *i);
a604ec7e	245	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
cbbd26b8	246	bool csum_and_copy_from_iter_full(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
b42b15fd	247
bc917be8 AV	248	int import_iovec(int type, const struct iovec __user * uvector,
	249	unsigned nr_segs, unsigned fast_segs,
	250	struct iovec *iov, struct iov_iter i);
	251
	252	#ifdef CONFIG_COMPAT
	253	struct compat_iovec;
	254	int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
	255	unsigned nr_segs, unsigned fast_segs,
	256	struct iovec *iov, struct iov_iter i);
	257	#endif
	258
	259	int import_single_range(int type, void __user *buf, size_t len,
	260	struct iovec iov, struct iov_iter i);
	261
09cf698a AV	262	int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
	263	int (f)(struct kvec vec, void *context),
	264	void *context);
	265
812ed032	266	#endif