Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | */ |
David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 9 | #ifndef __LINUX_UIO_H |
| 10 | #define __LINUX_UIO_H |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 12 | #include <linux/kernel.h> |
David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 13 | #include <uapi/linux/uio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 15 | struct page; |
Jiri Slaby | 812ed03 | 2009-07-29 15:04:19 -0700 | [diff] [blame] | 16 | |
| 17 | struct kvec { |
| 18 | void *iov_base; /* and that should *never* hold a userland pointer */ |
| 19 | size_t iov_len; |
| 20 | }; |
| 21 | |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 22 | enum { |
| 23 | ITER_IOVEC = 0, |
| 24 | ITER_KVEC = 2, |
| 25 | ITER_BVEC = 4, |
| 26 | }; |
| 27 | |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 28 | struct iov_iter { |
Al Viro | 71d8e53 | 2014-03-05 19:28:09 -0500 | [diff] [blame] | 29 | int type; |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 30 | size_t iov_offset; |
| 31 | size_t count; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 32 | union { |
| 33 | const struct iovec *iov; |
| 34 | const struct bio_vec *bvec; |
| 35 | }; |
| 36 | unsigned long nr_segs; |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 37 | }; |
| 38 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | /* |
| 40 | * Total number of bytes covered by an iovec. |
| 41 | * |
| 42 | * NOTE that it is not safe to use this function until all the iovec's |
| 43 | * segment lengths have been validated. Because the individual lengths can |
| 44 | * overflow a size_t when added together. |
| 45 | */ |
| 46 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) |
| 47 | { |
| 48 | unsigned long seg; |
| 49 | size_t ret = 0; |
| 50 | |
| 51 | for (seg = 0; seg < nr_segs; seg++) |
| 52 | ret += iov[seg].iov_len; |
| 53 | return ret; |
| 54 | } |
| 55 | |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 56 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
| 57 | { |
| 58 | return (struct iovec) { |
| 59 | .iov_base = iter->iov->iov_base + iter->iov_offset, |
| 60 | .iov_len = min(iter->count, |
| 61 | iter->iov->iov_len - iter->iov_offset), |
| 62 | }; |
| 63 | } |
| 64 | |
| 65 | #define iov_for_each(iov, iter, start) \ |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 66 | if (!((start).type & ITER_BVEC)) \ |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 67 | for (iter = (start); \ |
| 68 | (iter).count && \ |
| 69 | ((iov = iov_iter_iovec(&(iter))), 1); \ |
| 70 | iov_iter_advance(&(iter), (iov).iov_len)) |
| 71 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); |
Rusty Russell | d2f83e9 | 2013-05-17 09:05:21 +0930 | [diff] [blame] | 73 | |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 74 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
| 75 | struct iov_iter *i, unsigned long offset, size_t bytes); |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 76 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
| 77 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); |
| 78 | size_t iov_iter_single_seg_count(const struct iov_iter *i); |
Al Viro | 6e58e79 | 2014-02-03 17:07:03 -0500 | [diff] [blame] | 79 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
| 80 | struct iov_iter *i); |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 81 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
| 82 | struct iov_iter *i); |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 83 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
Al Viro | 71d8e53 | 2014-03-05 19:28:09 -0500 | [diff] [blame] | 84 | void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov, |
| 85 | unsigned long nr_segs, size_t count); |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 86 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
| 87 | size_t maxsize, size_t *start); |
Al Viro | 91f79c4 | 2014-03-21 04:58:33 -0400 | [diff] [blame] | 88 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, |
| 89 | size_t maxsize, size_t *start); |
Al Viro | f67da30 | 2014-03-19 01:16:16 -0400 | [diff] [blame] | 90 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 91 | |
| 92 | static inline size_t iov_iter_count(struct iov_iter *i) |
| 93 | { |
| 94 | return i->count; |
| 95 | } |
| 96 | |
Al Viro | 0c94933 | 2014-03-22 06:51:37 -0400 | [diff] [blame] | 97 | static inline void iov_iter_truncate(struct iov_iter *i, size_t count) |
| 98 | { |
| 99 | if (i->count > count) |
| 100 | i->count = count; |
| 101 | } |
| 102 | |
Al Viro | b42b15f | 2014-04-04 12:15:19 -0400 | [diff] [blame] | 103 | /* |
| 104 | * reexpand a previously truncated iterator; count must be no more than how much |
| 105 | * we had shrunk it. |
| 106 | */ |
| 107 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) |
| 108 | { |
| 109 | i->count = count; |
| 110 | } |
| 111 | |
Rusty Russell | d2f83e9 | 2013-05-17 09:05:21 +0930 | [diff] [blame] | 112 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); |
| 113 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len); |
Kent Overstreet | 9223687 | 2013-11-27 16:29:46 -0800 | [diff] [blame] | 114 | |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 115 | |
Jiri Slaby | 812ed03 | 2009-07-29 15:04:19 -0700 | [diff] [blame] | 116 | #endif |