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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
David Howells607ca462012-10-13 10:46:48 +01009#ifndef __LINUX_UIO_H
10#define __LINUX_UIO_H
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
Kent Overstreet92236872013-11-27 16:29:46 -080012#include <linux/kernel.h>
David Howells607ca462012-10-13 10:46:48 +010013#include <uapi/linux/uio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Kent Overstreet92236872013-11-27 16:29:46 -080015struct page;
Jiri Slaby812ed032009-07-29 15:04:19 -070016
17struct kvec {
18 void *iov_base; /* and that should *never* hold a userland pointer */
19 size_t iov_len;
20};
21
Al Viro62a80672014-04-04 23:12:29 -040022enum {
23 ITER_IOVEC = 0,
24 ITER_KVEC = 2,
25 ITER_BVEC = 4,
26};
27
Kent Overstreet92236872013-11-27 16:29:46 -080028struct iov_iter {
Al Viro71d8e532014-03-05 19:28:09 -050029 int type;
Kent Overstreet92236872013-11-27 16:29:46 -080030 size_t iov_offset;
31 size_t count;
Al Viro62a80672014-04-04 23:12:29 -040032 union {
33 const struct iovec *iov;
Al Viroa2804552014-11-27 14:48:42 -050034 const struct kvec *kvec;
Al Viro62a80672014-04-04 23:12:29 -040035 const struct bio_vec *bvec;
36 };
37 unsigned long nr_segs;
Kent Overstreet92236872013-11-27 16:29:46 -080038};
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040/*
41 * Total number of bytes covered by an iovec.
42 *
43 * NOTE that it is not safe to use this function until all the iovec's
44 * segment lengths have been validated. Because the individual lengths can
45 * overflow a size_t when added together.
46 */
47static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
48{
49 unsigned long seg;
50 size_t ret = 0;
51
52 for (seg = 0; seg < nr_segs; seg++)
53 ret += iov[seg].iov_len;
54 return ret;
55}
56
Kent Overstreet92236872013-11-27 16:29:46 -080057static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
58{
59 return (struct iovec) {
60 .iov_base = iter->iov->iov_base + iter->iov_offset,
61 .iov_len = min(iter->count,
62 iter->iov->iov_len - iter->iov_offset),
63 };
64}
65
66#define iov_for_each(iov, iter, start) \
Al Viro62a80672014-04-04 23:12:29 -040067 if (!((start).type & ITER_BVEC)) \
Kent Overstreet92236872013-11-27 16:29:46 -080068 for (iter = (start); \
69 (iter).count && \
70 ((iov = iov_iter_iovec(&(iter))), 1); \
71 iov_iter_advance(&(iter), (iov).iov_len))
72
Linus Torvalds1da177e2005-04-16 15:20:36 -070073unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
Rusty Russelld2f83e92013-05-17 09:05:21 +093074
Kent Overstreet92236872013-11-27 16:29:46 -080075size_t iov_iter_copy_from_user_atomic(struct page *page,
76 struct iov_iter *i, unsigned long offset, size_t bytes);
Kent Overstreet92236872013-11-27 16:29:46 -080077void iov_iter_advance(struct iov_iter *i, size_t bytes);
78int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
Anton Altaparmakov171a0202015-03-11 10:43:31 -040079int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes);
Kent Overstreet92236872013-11-27 16:29:46 -080080size_t iov_iter_single_seg_count(const struct iov_iter *i);
Al Viro6e58e792014-02-03 17:07:03 -050081size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
82 struct iov_iter *i);
Al Virof0d1bec2014-04-03 15:05:18 -040083size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
84 struct iov_iter *i);
Al Viro36f7a8a2015-12-06 16:49:22 -050085size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
Matthew Wilcoxc35e0242014-08-01 09:27:22 -040086size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
Al Viroaa583092014-11-27 20:27:08 -050087size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
Matthew Wilcoxc35e0242014-08-01 09:27:22 -040088size_t iov_iter_zero(size_t bytes, struct iov_iter *);
Al Viro886a3912014-03-05 13:50:45 -050089unsigned long iov_iter_alignment(const struct iov_iter *i);
Al Viro357f4352016-04-08 19:05:19 -040090unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
Al Viro71d8e532014-03-05 19:28:09 -050091void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
92 unsigned long nr_segs, size_t count);
Al Viro05afcb72015-01-23 01:08:07 -050093void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
94 unsigned long nr_segs, size_t count);
95void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
Al Viroabb78f82014-11-24 14:46:11 -050096 unsigned long nr_segs, size_t count);
Al Viro7b2c99d2014-03-15 04:05:57 -040097ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
Miklos Szeredi2c809292014-09-24 17:09:11 +020098 size_t maxsize, unsigned maxpages, size_t *start);
Al Viro91f79c42014-03-21 04:58:33 -040099ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
100 size_t maxsize, size_t *start);
Al Virof67da302014-03-19 01:16:16 -0400101int iov_iter_npages(const struct iov_iter *i, int maxpages);
Kent Overstreet92236872013-11-27 16:29:46 -0800102
Al Viro4b8164b2015-01-31 20:08:47 -0500103const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
104
Kent Overstreet92236872013-11-27 16:29:46 -0800105static inline size_t iov_iter_count(struct iov_iter *i)
106{
107 return i->count;
108}
109
Al Viro777eda22014-12-17 04:46:46 -0500110static inline bool iter_is_iovec(struct iov_iter *i)
111{
112 return !(i->type & (ITER_BVEC | ITER_KVEC));
113}
114
Al Viro0b86dbf2014-06-23 08:44:40 +0100115/*
Omar Sandovalbd8e0ff2015-03-17 14:04:02 -0700116 * Get one of READ or WRITE out of iter->type without any other flags OR'd in
117 * with it.
118 *
119 * The ?: is just for type safety.
120 */
121#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
122
123/*
Al Viro0b86dbf2014-06-23 08:44:40 +0100124 * Cap the iov_iter by given limit; note that the second argument is
125 * *not* the new size - it's upper limit for such. Passing it a value
126 * greater than the amount of data in iov_iter is fine - it'll just do
127 * nothing in that case.
128 */
129static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
Al Viro0c949332014-03-22 06:51:37 -0400130{
Al Viro0b86dbf2014-06-23 08:44:40 +0100131 /*
132 * count doesn't have to fit in size_t - comparison extends both
133 * operands to u64 here and any value that would be truncated by
134 * conversion in assignement is by definition greater than all
135 * values of size_t, including old i->count.
136 */
Al Viro0c949332014-03-22 06:51:37 -0400137 if (i->count > count)
138 i->count = count;
139}
140
Al Virob42b15f2014-04-04 12:15:19 -0400141/*
142 * reexpand a previously truncated iterator; count must be no more than how much
143 * we had shrunk it.
144 */
145static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
146{
147 i->count = count;
148}
Al Viro36f7a8a2015-12-06 16:49:22 -0500149size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
Al Viroa604ec72014-11-24 01:08:00 -0500150size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
Al Virob42b15f2014-04-04 12:15:19 -0400151
Al Virobc917be2015-03-21 17:45:43 -0400152int import_iovec(int type, const struct iovec __user * uvector,
153 unsigned nr_segs, unsigned fast_segs,
154 struct iovec **iov, struct iov_iter *i);
155
156#ifdef CONFIG_COMPAT
157struct compat_iovec;
158int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
159 unsigned nr_segs, unsigned fast_segs,
160 struct iovec **iov, struct iov_iter *i);
161#endif
162
163int import_single_range(int type, void __user *buf, size_t len,
164 struct iovec *iov, struct iov_iter *i);
165
Jiri Slaby812ed032009-07-29 15:04:19 -0700166#endif