[linux-block.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 {
	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 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 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(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);

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
92236878	30	struct iov_iter {
8cd54c1c AV	31	u8 iter_type;
8cd54c1c AV	32	bool data_source;
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;
7ff50620	39	struct xarray *xarray;
241699cd AV	40	struct pipe_inode_info *pipe;
	41	};
	42	union {
	43	unsigned long nr_segs;
27c0e374	44	struct {
8cefc107 DH	45	unsigned int head;
8cefc107 DH	46	unsigned int start_head;
27c0e374	47	};
7ff50620	48	loff_t xarray_start;
62a8067a	49	};
92236878 KO	50	};
92236878 KO	51
00e23707 DH	52	static inline enum iter_type iov_iter_type(const struct iov_iter *i)
00e23707 DH	53	{
8cd54c1c	54	return i->iter_type;
00e23707 DH	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
7ff50620 DH	82	static inline bool iov_iter_is_xarray(const struct iov_iter *i)
	83	{
	84	return iov_iter_type(i) == ITER_XARRAY;
	85	}
	86
00e23707 DH	87	static inline unsigned char iov_iter_rw(const struct iov_iter *i)
00e23707 DH	88	{
8cd54c1c	89	return i->data_source ? WRITE : READ;
00e23707 DH	90	}
00e23707 DH	91
1da177e4 LT	92	/*
	93	* Total number of bytes covered by an iovec.
	94	*
	95	* NOTE that it is not safe to use this function until all the iovec's
	96	* segment lengths have been validated. Because the individual lengths can
	97	* overflow a size_t when added together.
	98	*/
	99	static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
	100	{
	101	unsigned long seg;
	102	size_t ret = 0;
	103
	104	for (seg = 0; seg < nr_segs; seg++)
	105	ret += iov[seg].iov_len;
	106	return ret;
	107	}
	108
92236878 KO	109	static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
	110	{
	111	return (struct iovec) {
	112	.iov_base = iter->iov->iov_base + iter->iov_offset,
	113	.iov_len = min(iter->count,
	114	iter->iov->iov_len - iter->iov_offset),
	115	};
	116	}
	117
92236878 KO	118	size_t iov_iter_copy_from_user_atomic(struct page *page,
92236878 KO	119	struct iov_iter *i, unsigned long offset, size_t bytes);
92236878	120	void iov_iter_advance(struct iov_iter *i, size_t bytes);
27c0e374	121	void iov_iter_revert(struct iov_iter *i, size_t bytes);
8409a0d2	122	int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
92236878	123	size_t iov_iter_single_seg_count(const struct iov_iter *i);
6e58e79d AV	124	size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
6e58e79d AV	125	struct iov_iter *i);
f0d1bec9 AV	126	size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
f0d1bec9 AV	127	struct iov_iter *i);
aa28de27 AV	128
	129	size_t _copy_to_iter(const void addr, size_t bytes, struct iov_iter i);
	130	size_t _copy_from_iter(void addr, size_t bytes, struct iov_iter i);
aa28de27	131	size_t _copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i);
aa28de27 AV	132
	133	static __always_inline __must_check
	134	size_t copy_to_iter(const void addr, size_t bytes, struct iov_iter i)
	135	{
	136	if (unlikely(!check_copy_size(addr, bytes, true)))
c43aeb19	137	return 0;
aa28de27 AV	138	else
	139	return _copy_to_iter(addr, bytes, i);
	140	}
	141
	142	static __always_inline __must_check
	143	size_t copy_from_iter(void addr, size_t bytes, struct iov_iter i)
	144	{
	145	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	146	return 0;
aa28de27 AV	147	else
	148	return _copy_from_iter(addr, bytes, i);
	149	}
	150
	151	static __always_inline __must_check
	152	bool copy_from_iter_full(void addr, size_t bytes, struct iov_iter i)
	153	{
4b6c132b AV	154	size_t copied = copy_from_iter(addr, bytes, i);
	155	if (likely(copied == bytes))
	156	return true;
	157	iov_iter_revert(i, copied);
	158	return false;
aa28de27 AV	159	}
	160
	161	static __always_inline __must_check
	162	size_t copy_from_iter_nocache(void addr, size_t bytes, struct iov_iter i)
	163	{
	164	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	165	return 0;
aa28de27 AV	166	else
	167	return _copy_from_iter_nocache(addr, bytes, i);
	168	}
	169
	170	static __always_inline __must_check
	171	bool copy_from_iter_full_nocache(void addr, size_t bytes, struct iov_iter i)
	172	{
4b6c132b AV	173	size_t copied = copy_from_iter_nocache(addr, bytes, i);
	174	if (likely(copied == bytes))
	175	return true;
	176	iov_iter_revert(i, copied);
	177	return false;
aa28de27 AV	178	}
aa28de27 AV	179
0aed55af DW	180	#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
	181	/*
	182	* Note, users like pmem that depend on the stricter semantics of
	183	* copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
	184	* IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
	185	* destination is flushed from the cache on return.
	186	*/
6a37e940	187	size_t _copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i);
0aed55af	188	#else
6a37e940 LT	189	#define _copy_from_iter_flushcache _copy_from_iter_nocache
	190	#endif
	191
ec6347bb DW	192	#ifdef CONFIG_ARCH_HAS_COPY_MC
ec6347bb DW	193	size_t _copy_mc_to_iter(const void addr, size_t bytes, struct iov_iter i);
8780356e	194	#else
ec6347bb	195	#define _copy_mc_to_iter _copy_to_iter
8780356e DW	196	#endif
8780356e DW	197
6a37e940 LT	198	static __always_inline __must_check
6a37e940 LT	199	size_t copy_from_iter_flushcache(void addr, size_t bytes, struct iov_iter i)
0aed55af	200	{
6a37e940	201	if (unlikely(!check_copy_size(addr, bytes, false)))
c43aeb19	202	return 0;
6a37e940 LT	203	else
6a37e940 LT	204	return _copy_from_iter_flushcache(addr, bytes, i);
0aed55af	205	}
6a37e940	206
8780356e	207	static __always_inline __must_check
ec6347bb	208	size_t copy_mc_to_iter(void addr, size_t bytes, struct iov_iter i)
8780356e	209	{
dfb06cba	210	if (unlikely(!check_copy_size(addr, bytes, true)))
8780356e DW	211	return 0;
8780356e DW	212	else
ec6347bb	213	return _copy_mc_to_iter(addr, bytes, i);
8780356e DW	214	}
8780356e DW	215
c35e0248	216	size_t iov_iter_zero(size_t bytes, struct iov_iter *);
886a3911	217	unsigned long iov_iter_alignment(const struct iov_iter *i);
357f435d	218	unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
aa563d7b	219	void iov_iter_init(struct iov_iter i, unsigned int direction, const struct iovec iov,
71d8e532	220	unsigned long nr_segs, size_t count);
aa563d7b	221	void iov_iter_kvec(struct iov_iter i, unsigned int direction, const struct kvec kvec,
05afcb77	222	unsigned long nr_segs, size_t count);
aa563d7b	223	void iov_iter_bvec(struct iov_iter i, unsigned int direction, const struct bio_vec bvec,
abb78f87	224	unsigned long nr_segs, size_t count);
aa563d7b	225	void iov_iter_pipe(struct iov_iter i, unsigned int direction, struct pipe_inode_info pipe,
241699cd	226	size_t count);
9ea9ce04	227	void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
7ff50620 DH	228	void iov_iter_xarray(struct iov_iter i, unsigned int direction, struct xarray xarray,
7ff50620 DH	229	loff_t start, 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	}
52cbd23a WB	269
	270	struct csum_state {
	271	__wsum csum;
	272	size_t off;
	273	};
	274
	275	size_t csum_and_copy_to_iter(const void addr, size_t bytes, void csstate, struct iov_iter *i);
a604ec7e	276	size_t csum_and_copy_from_iter(void addr, size_t bytes, __wsum csum, struct iov_iter *i);
4b6c132b AV	277
	278	static __always_inline __must_check
	279	bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
	280	__wsum csum, struct iov_iter i)
	281	{
	282	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
	283	if (likely(copied == bytes))
	284	return true;
	285	iov_iter_revert(i, copied);
	286	return false;
	287	}
d05f4435 SG	288	size_t hash_and_copy_to_iter(const void addr, size_t bytes, void hashp,
d05f4435 SG	289	struct iov_iter *i);
b42b15fd	290
bfdc5970 CH	291	struct iovec iovec_from_user(const struct iovec __user uvector,
	292	unsigned long nr_segs, unsigned long fast_segs,
	293	struct iovec *fast_iov, bool compat);
	294	ssize_t import_iovec(int type, const struct iovec __user *uvec,
	295	unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
	296	struct iov_iter *i);
	297	ssize_t __import_iovec(int type, const struct iovec __user *uvec,
	298	unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
	299	struct iov_iter *i, bool compat);
bc917be8 AV	300	int import_single_range(int type, void __user *buf, size_t len,
	301	struct iovec iov, struct iov_iter i);
	302
812ed032	303	#endif