Thomas Gleixner | 457c899 | 2019-05-19 13:08:55 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Herbert Xu | 7999096 | 2020-06-12 16:57:37 +1000 | [diff] [blame] | 2 | #include <crypto/hash.h> |
Al Viro | 4f18cd3 | 2014-02-05 19:11:33 -0500 | [diff] [blame] | 3 | #include <linux/export.h> |
Christoph Hellwig | 2f8b544 | 2016-11-01 07:40:13 -0600 | [diff] [blame] | 4 | #include <linux/bvec.h> |
Albert van der Linde | 4d0e9df | 2020-10-15 20:13:50 -0700 | [diff] [blame] | 5 | #include <linux/fault-inject-usercopy.h> |
Al Viro | 4f18cd3 | 2014-02-05 19:11:33 -0500 | [diff] [blame] | 6 | #include <linux/uio.h> |
| 7 | #include <linux/pagemap.h> |
Ira Weiny | 2896199 | 2021-05-04 18:40:03 -0700 | [diff] [blame] | 8 | #include <linux/highmem.h> |
Al Viro | 91f79c4 | 2014-03-21 04:58:33 -0400 | [diff] [blame] | 9 | #include <linux/slab.h> |
| 10 | #include <linux/vmalloc.h> |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 11 | #include <linux/splice.h> |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 12 | #include <linux/compat.h> |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 13 | #include <net/checksum.h> |
Sagi Grimberg | d05f443 | 2018-12-03 17:52:09 -0800 | [diff] [blame] | 14 | #include <linux/scatterlist.h> |
Marco Elver | d0ef4c3 | 2020-01-21 17:05:11 +0100 | [diff] [blame] | 15 | #include <linux/instrumented.h> |
Al Viro | 4f18cd3 | 2014-02-05 19:11:33 -0500 | [diff] [blame] | 16 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 17 | #define PIPE_PARANOIA /* for now */ |
| 18 | |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 19 | /* covers ubuf and kbuf alike */ |
| 20 | #define iterate_buf(i, n, base, len, off, __p, STEP) { \ |
| 21 | size_t __maybe_unused off = 0; \ |
| 22 | len = n; \ |
| 23 | base = __p + i->iov_offset; \ |
| 24 | len -= (STEP); \ |
| 25 | i->iov_offset += len; \ |
| 26 | n = len; \ |
| 27 | } |
| 28 | |
Al Viro | 5c67aa9 | 2021-04-25 23:57:42 -0400 | [diff] [blame] | 29 | /* covers iovec and kvec alike */ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 30 | #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 31 | size_t off = 0; \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 32 | size_t skip = i->iov_offset; \ |
Al Viro | 7a1bcb5 | 2021-04-25 23:46:09 -0400 | [diff] [blame] | 33 | do { \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 34 | len = min(n, __p->iov_len - skip); \ |
| 35 | if (likely(len)) { \ |
| 36 | base = __p->iov_base + skip; \ |
| 37 | len -= (STEP); \ |
| 38 | off += len; \ |
| 39 | skip += len; \ |
| 40 | n -= len; \ |
Al Viro | 7a1bcb5 | 2021-04-25 23:46:09 -0400 | [diff] [blame] | 41 | if (skip < __p->iov_len) \ |
| 42 | break; \ |
| 43 | } \ |
| 44 | __p++; \ |
| 45 | skip = 0; \ |
| 46 | } while (n); \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 47 | i->iov_offset = skip; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 48 | n = off; \ |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 49 | } |
| 50 | |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 51 | #define iterate_bvec(i, n, base, len, off, p, STEP) { \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 52 | size_t off = 0; \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 53 | unsigned skip = i->iov_offset; \ |
Al Viro | 7491a2b | 2021-04-26 20:19:14 -0400 | [diff] [blame] | 54 | while (n) { \ |
| 55 | unsigned offset = p->bv_offset + skip; \ |
Al Viro | 1b4fb5f | 2021-04-26 20:33:42 -0400 | [diff] [blame] | 56 | unsigned left; \ |
Al Viro | 21b56c8 | 2021-04-26 20:50:05 -0400 | [diff] [blame] | 57 | void *kaddr = kmap_local_page(p->bv_page + \ |
| 58 | offset / PAGE_SIZE); \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 59 | base = kaddr + offset % PAGE_SIZE; \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 60 | len = min(min(n, (size_t)(p->bv_len - skip)), \ |
Al Viro | 7491a2b | 2021-04-26 20:19:14 -0400 | [diff] [blame] | 61 | (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ |
Al Viro | 1b4fb5f | 2021-04-26 20:33:42 -0400 | [diff] [blame] | 62 | left = (STEP); \ |
Al Viro | 21b56c8 | 2021-04-26 20:50:05 -0400 | [diff] [blame] | 63 | kunmap_local(kaddr); \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 64 | len -= left; \ |
| 65 | off += len; \ |
| 66 | skip += len; \ |
Al Viro | 7491a2b | 2021-04-26 20:19:14 -0400 | [diff] [blame] | 67 | if (skip == p->bv_len) { \ |
| 68 | skip = 0; \ |
| 69 | p++; \ |
| 70 | } \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 71 | n -= len; \ |
Al Viro | 1b4fb5f | 2021-04-26 20:33:42 -0400 | [diff] [blame] | 72 | if (left) \ |
| 73 | break; \ |
Al Viro | 7491a2b | 2021-04-26 20:19:14 -0400 | [diff] [blame] | 74 | } \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 75 | i->iov_offset = skip; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 76 | n = off; \ |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 77 | } |
| 78 | |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 79 | #define iterate_xarray(i, n, base, len, __off, STEP) { \ |
Al Viro | 1b4fb5f | 2021-04-26 20:33:42 -0400 | [diff] [blame] | 80 | __label__ __out; \ |
Al Viro | 622838f | 2021-05-02 11:13:09 -0400 | [diff] [blame] | 81 | size_t __off = 0; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 82 | struct folio *folio; \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 83 | loff_t start = i->xarray_start + i->iov_offset; \ |
Al Viro | 4b179e9 | 2021-05-04 17:50:07 -0400 | [diff] [blame] | 84 | pgoff_t index = start / PAGE_SIZE; \ |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 85 | XA_STATE(xas, i->xarray, index); \ |
| 86 | \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 87 | len = PAGE_SIZE - offset_in_page(start); \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 88 | rcu_read_lock(); \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 89 | xas_for_each(&xas, folio, ULONG_MAX) { \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 90 | unsigned left; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 91 | size_t offset; \ |
| 92 | if (xas_retry(&xas, folio)) \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 93 | continue; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 94 | if (WARN_ON(xa_is_value(folio))) \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 95 | break; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 96 | if (WARN_ON(folio_test_hugetlb(folio))) \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 97 | break; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 98 | offset = offset_in_folio(folio, start + __off); \ |
| 99 | while (offset < folio_size(folio)) { \ |
| 100 | base = kmap_local_folio(folio, offset); \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 101 | len = min(n, len); \ |
| 102 | left = (STEP); \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 103 | kunmap_local(base); \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 104 | len -= left; \ |
| 105 | __off += len; \ |
| 106 | n -= len; \ |
| 107 | if (left || n == 0) \ |
| 108 | goto __out; \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 109 | offset += len; \ |
| 110 | len = PAGE_SIZE; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 111 | } \ |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 112 | } \ |
Al Viro | 1b4fb5f | 2021-04-26 20:33:42 -0400 | [diff] [blame] | 113 | __out: \ |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 114 | rcu_read_unlock(); \ |
Matthew Wilcox (Oracle) | 821979f | 2021-11-28 19:18:27 -0500 | [diff] [blame] | 115 | i->iov_offset += __off; \ |
Al Viro | 622838f | 2021-05-02 11:13:09 -0400 | [diff] [blame] | 116 | n = __off; \ |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 117 | } |
| 118 | |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 119 | #define __iterate_and_advance(i, n, base, len, off, I, K) { \ |
Al Viro | dd254f5 | 2016-05-09 11:54:48 -0400 | [diff] [blame] | 120 | if (unlikely(i->count < n)) \ |
| 121 | n = i->count; \ |
Al Viro | f5da835 | 2021-04-28 20:59:08 -0400 | [diff] [blame] | 122 | if (likely(n)) { \ |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 123 | if (likely(iter_is_ubuf(i))) { \ |
| 124 | void __user *base; \ |
| 125 | size_t len; \ |
| 126 | iterate_buf(i, n, base, len, off, \ |
| 127 | i->ubuf, (I)) \ |
| 128 | } else if (likely(iter_is_iovec(i))) { \ |
Al Viro | 5c67aa9 | 2021-04-25 23:57:42 -0400 | [diff] [blame] | 129 | const struct iovec *iov = i->iov; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 130 | void __user *base; \ |
| 131 | size_t len; \ |
| 132 | iterate_iovec(i, n, base, len, off, \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 133 | iov, (I)) \ |
Al Viro | dd254f5 | 2016-05-09 11:54:48 -0400 | [diff] [blame] | 134 | i->nr_segs -= iov - i->iov; \ |
| 135 | i->iov = iov; \ |
Al Viro | 28f38db | 2021-06-02 17:25:59 -0400 | [diff] [blame] | 136 | } else if (iov_iter_is_bvec(i)) { \ |
| 137 | const struct bio_vec *bvec = i->bvec; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 138 | void *base; \ |
| 139 | size_t len; \ |
| 140 | iterate_bvec(i, n, base, len, off, \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 141 | bvec, (K)) \ |
Al Viro | 7491a2b | 2021-04-26 20:19:14 -0400 | [diff] [blame] | 142 | i->nr_segs -= bvec - i->bvec; \ |
| 143 | i->bvec = bvec; \ |
Al Viro | 28f38db | 2021-06-02 17:25:59 -0400 | [diff] [blame] | 144 | } else if (iov_iter_is_kvec(i)) { \ |
Al Viro | 5c67aa9 | 2021-04-25 23:57:42 -0400 | [diff] [blame] | 145 | const struct kvec *kvec = i->kvec; \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 146 | void *base; \ |
| 147 | size_t len; \ |
| 148 | iterate_iovec(i, n, base, len, off, \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 149 | kvec, (K)) \ |
Al Viro | 28f38db | 2021-06-02 17:25:59 -0400 | [diff] [blame] | 150 | i->nr_segs -= kvec - i->kvec; \ |
| 151 | i->kvec = kvec; \ |
| 152 | } else if (iov_iter_is_xarray(i)) { \ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 153 | void *base; \ |
| 154 | size_t len; \ |
| 155 | iterate_xarray(i, n, base, len, off, \ |
Al Viro | a6e4ec7 | 2021-05-02 13:03:41 -0400 | [diff] [blame] | 156 | (K)) \ |
Al Viro | 7ce2a91 | 2014-11-27 13:59:45 -0500 | [diff] [blame] | 157 | } \ |
Al Viro | dd254f5 | 2016-05-09 11:54:48 -0400 | [diff] [blame] | 158 | i->count -= n; \ |
Al Viro | 7ce2a91 | 2014-11-27 13:59:45 -0500 | [diff] [blame] | 159 | } \ |
Al Viro | 7ce2a91 | 2014-11-27 13:59:45 -0500 | [diff] [blame] | 160 | } |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 161 | #define iterate_and_advance(i, n, base, len, off, I, K) \ |
| 162 | __iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) |
Al Viro | 7ce2a91 | 2014-11-27 13:59:45 -0500 | [diff] [blame] | 163 | |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 164 | static int copyout(void __user *to, const void *from, size_t n) |
| 165 | { |
Albert van der Linde | 4d0e9df | 2020-10-15 20:13:50 -0700 | [diff] [blame] | 166 | if (should_fail_usercopy()) |
| 167 | return n; |
Linus Torvalds | 96d4f26 | 2019-01-03 18:57:57 -0800 | [diff] [blame] | 168 | if (access_ok(to, n)) { |
Marco Elver | d0ef4c3 | 2020-01-21 17:05:11 +0100 | [diff] [blame] | 169 | instrument_copy_to_user(to, from, n); |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 170 | n = raw_copy_to_user(to, from, n); |
| 171 | } |
| 172 | return n; |
| 173 | } |
| 174 | |
| 175 | static int copyin(void *to, const void __user *from, size_t n) |
| 176 | { |
Alexander Potapenko | 33b75c1 | 2022-09-15 17:03:37 +0200 | [diff] [blame] | 177 | size_t res = n; |
| 178 | |
Albert van der Linde | 4d0e9df | 2020-10-15 20:13:50 -0700 | [diff] [blame] | 179 | if (should_fail_usercopy()) |
| 180 | return n; |
Linus Torvalds | 96d4f26 | 2019-01-03 18:57:57 -0800 | [diff] [blame] | 181 | if (access_ok(from, n)) { |
Alexander Potapenko | 33b75c1 | 2022-09-15 17:03:37 +0200 | [diff] [blame] | 182 | instrument_copy_from_user_before(to, from, n); |
| 183 | res = raw_copy_from_user(to, from, n); |
| 184 | instrument_copy_from_user_after(to, from, n, res); |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 185 | } |
Alexander Potapenko | 33b75c1 | 2022-09-15 17:03:37 +0200 | [diff] [blame] | 186 | return res; |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 187 | } |
| 188 | |
Al Viro | 2dcedb2 | 2022-06-14 10:24:37 -0400 | [diff] [blame] | 189 | static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, |
| 190 | unsigned int slot) |
| 191 | { |
| 192 | return &pipe->bufs[slot & (pipe->ring_size - 1)]; |
| 193 | } |
| 194 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 195 | #ifdef PIPE_PARANOIA |
| 196 | static bool sanity(const struct iov_iter *i) |
| 197 | { |
| 198 | struct pipe_inode_info *pipe = i->pipe; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 199 | unsigned int p_head = pipe->head; |
| 200 | unsigned int p_tail = pipe->tail; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 201 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); |
| 202 | unsigned int i_head = i->head; |
| 203 | unsigned int idx; |
| 204 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 205 | if (i->last_offset) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 206 | struct pipe_buffer *p; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 207 | if (unlikely(p_occupancy == 0)) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 208 | goto Bad; // pipe must be non-empty |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 209 | if (unlikely(i_head != p_head - 1)) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 210 | goto Bad; // must be at the last buffer... |
| 211 | |
Al Viro | 2dcedb2 | 2022-06-14 10:24:37 -0400 | [diff] [blame] | 212 | p = pipe_buf(pipe, i_head); |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 213 | if (unlikely(p->offset + p->len != abs(i->last_offset))) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 214 | goto Bad; // ... at the end of segment |
| 215 | } else { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 216 | if (i_head != p_head) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 217 | goto Bad; // must be right after the last buffer |
| 218 | } |
| 219 | return true; |
| 220 | Bad: |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 221 | printk(KERN_ERR "idx = %d, offset = %d\n", i_head, i->last_offset); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 222 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", |
| 223 | p_head, p_tail, pipe->ring_size); |
| 224 | for (idx = 0; idx < pipe->ring_size; idx++) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 225 | printk(KERN_ERR "[%p %p %d %d]\n", |
| 226 | pipe->bufs[idx].ops, |
| 227 | pipe->bufs[idx].page, |
| 228 | pipe->bufs[idx].offset, |
| 229 | pipe->bufs[idx].len); |
| 230 | WARN_ON(1); |
| 231 | return false; |
| 232 | } |
| 233 | #else |
| 234 | #define sanity(i) true |
| 235 | #endif |
| 236 | |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 237 | static struct page *push_anon(struct pipe_inode_info *pipe, unsigned size) |
| 238 | { |
| 239 | struct page *page = alloc_page(GFP_USER); |
| 240 | if (page) { |
| 241 | struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); |
| 242 | *buf = (struct pipe_buffer) { |
| 243 | .ops = &default_pipe_buf_ops, |
| 244 | .page = page, |
| 245 | .offset = 0, |
| 246 | .len = size |
| 247 | }; |
| 248 | } |
| 249 | return page; |
| 250 | } |
| 251 | |
| 252 | static void push_page(struct pipe_inode_info *pipe, struct page *page, |
| 253 | unsigned int offset, unsigned int size) |
| 254 | { |
| 255 | struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); |
| 256 | *buf = (struct pipe_buffer) { |
| 257 | .ops = &page_cache_pipe_buf_ops, |
| 258 | .page = page, |
| 259 | .offset = offset, |
| 260 | .len = size |
| 261 | }; |
| 262 | get_page(page); |
| 263 | } |
| 264 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 265 | static inline int last_offset(const struct pipe_buffer *buf) |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 266 | { |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 267 | if (buf->ops == &default_pipe_buf_ops) |
| 268 | return buf->len; // buf->offset is 0 for those |
| 269 | else |
| 270 | return -(buf->offset + buf->len); |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 271 | } |
| 272 | |
| 273 | static struct page *append_pipe(struct iov_iter *i, size_t size, |
| 274 | unsigned int *off) |
| 275 | { |
| 276 | struct pipe_inode_info *pipe = i->pipe; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 277 | int offset = i->last_offset; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 278 | struct pipe_buffer *buf; |
| 279 | struct page *page; |
| 280 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 281 | if (offset > 0 && offset < PAGE_SIZE) { |
| 282 | // some space in the last buffer; add to it |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 283 | buf = pipe_buf(pipe, pipe->head - 1); |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 284 | size = min_t(size_t, size, PAGE_SIZE - offset); |
| 285 | buf->len += size; |
| 286 | i->last_offset += size; |
| 287 | i->count -= size; |
| 288 | *off = offset; |
| 289 | return buf->page; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 290 | } |
| 291 | // OK, we need a new buffer |
| 292 | *off = 0; |
| 293 | size = min_t(size_t, size, PAGE_SIZE); |
| 294 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
| 295 | return NULL; |
| 296 | page = push_anon(pipe, size); |
| 297 | if (!page) |
| 298 | return NULL; |
| 299 | i->head = pipe->head - 1; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 300 | i->last_offset = size; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 301 | i->count -= size; |
| 302 | return page; |
| 303 | } |
| 304 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 305 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
| 306 | struct iov_iter *i) |
| 307 | { |
| 308 | struct pipe_inode_info *pipe = i->pipe; |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 309 | unsigned int head = pipe->head; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 310 | |
| 311 | if (unlikely(bytes > i->count)) |
| 312 | bytes = i->count; |
| 313 | |
| 314 | if (unlikely(!bytes)) |
| 315 | return 0; |
| 316 | |
| 317 | if (!sanity(i)) |
| 318 | return 0; |
| 319 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 320 | if (offset && i->last_offset == -offset) { // could we merge it? |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 321 | struct pipe_buffer *buf = pipe_buf(pipe, head - 1); |
| 322 | if (buf->page == page) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 323 | buf->len += bytes; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 324 | i->last_offset -= bytes; |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 325 | i->count -= bytes; |
| 326 | return bytes; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 327 | } |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 328 | } |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 329 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 330 | return 0; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 331 | |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 332 | push_page(pipe, page, offset, bytes); |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 333 | i->last_offset = -(offset + bytes); |
Al Viro | 47b7fca | 2022-06-13 14:30:15 -0400 | [diff] [blame] | 334 | i->head = head; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 335 | i->count -= bytes; |
| 336 | return bytes; |
| 337 | } |
| 338 | |
Al Viro | 4f18cd3 | 2014-02-05 19:11:33 -0500 | [diff] [blame] | 339 | /* |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 340 | * fault_in_iov_iter_readable - fault in iov iterator for reading |
| 341 | * @i: iterator |
| 342 | * @size: maximum length |
Anton Altaparmakov | 171a020 | 2015-03-11 10:43:31 -0400 | [diff] [blame] | 343 | * |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 344 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
| 345 | * @size. For each iovec, fault in each page that constitutes the iovec. |
| 346 | * |
| 347 | * Returns the number of bytes not faulted in (like copy_to_user() and |
| 348 | * copy_from_user()). |
| 349 | * |
| 350 | * Always returns 0 for non-userspace iterators. |
Anton Altaparmakov | 171a020 | 2015-03-11 10:43:31 -0400 | [diff] [blame] | 351 | */ |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 352 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) |
Anton Altaparmakov | 171a020 | 2015-03-11 10:43:31 -0400 | [diff] [blame] | 353 | { |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 354 | if (iter_is_ubuf(i)) { |
| 355 | size_t n = min(size, iov_iter_count(i)); |
| 356 | n -= fault_in_readable(i->ubuf + i->iov_offset, n); |
| 357 | return size - n; |
| 358 | } else if (iter_is_iovec(i)) { |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 359 | size_t count = min(size, iov_iter_count(i)); |
Al Viro | 8409a0d | 2021-05-02 11:57:37 -0400 | [diff] [blame] | 360 | const struct iovec *p; |
| 361 | size_t skip; |
| 362 | |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 363 | size -= count; |
| 364 | for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { |
| 365 | size_t len = min(count, p->iov_len - skip); |
| 366 | size_t ret; |
Al Viro | 8409a0d | 2021-05-02 11:57:37 -0400 | [diff] [blame] | 367 | |
| 368 | if (unlikely(!len)) |
| 369 | continue; |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 370 | ret = fault_in_readable(p->iov_base + skip, len); |
| 371 | count -= len - ret; |
| 372 | if (ret) |
| 373 | break; |
Al Viro | 8409a0d | 2021-05-02 11:57:37 -0400 | [diff] [blame] | 374 | } |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 375 | return count + size; |
Anton Altaparmakov | 171a020 | 2015-03-11 10:43:31 -0400 | [diff] [blame] | 376 | } |
| 377 | return 0; |
| 378 | } |
Andreas Gruenbacher | a629459 | 2021-08-02 14:54:16 +0200 | [diff] [blame] | 379 | EXPORT_SYMBOL(fault_in_iov_iter_readable); |
Anton Altaparmakov | 171a020 | 2015-03-11 10:43:31 -0400 | [diff] [blame] | 380 | |
Andreas Gruenbacher | cdd591f | 2021-07-05 17:26:28 +0200 | [diff] [blame] | 381 | /* |
| 382 | * fault_in_iov_iter_writeable - fault in iov iterator for writing |
| 383 | * @i: iterator |
| 384 | * @size: maximum length |
| 385 | * |
| 386 | * Faults in the iterator using get_user_pages(), i.e., without triggering |
| 387 | * hardware page faults. This is primarily useful when we already know that |
| 388 | * some or all of the pages in @i aren't in memory. |
| 389 | * |
| 390 | * Returns the number of bytes not faulted in, like copy_to_user() and |
| 391 | * copy_from_user(). |
| 392 | * |
| 393 | * Always returns 0 for non-user-space iterators. |
| 394 | */ |
| 395 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) |
| 396 | { |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 397 | if (iter_is_ubuf(i)) { |
| 398 | size_t n = min(size, iov_iter_count(i)); |
| 399 | n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); |
| 400 | return size - n; |
| 401 | } else if (iter_is_iovec(i)) { |
Andreas Gruenbacher | cdd591f | 2021-07-05 17:26:28 +0200 | [diff] [blame] | 402 | size_t count = min(size, iov_iter_count(i)); |
| 403 | const struct iovec *p; |
| 404 | size_t skip; |
| 405 | |
| 406 | size -= count; |
| 407 | for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { |
| 408 | size_t len = min(count, p->iov_len - skip); |
| 409 | size_t ret; |
| 410 | |
| 411 | if (unlikely(!len)) |
| 412 | continue; |
| 413 | ret = fault_in_safe_writeable(p->iov_base + skip, len); |
| 414 | count -= len - ret; |
| 415 | if (ret) |
| 416 | break; |
| 417 | } |
| 418 | return count + size; |
| 419 | } |
| 420 | return 0; |
| 421 | } |
| 422 | EXPORT_SYMBOL(fault_in_iov_iter_writeable); |
| 423 | |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 424 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
Al Viro | 71d8e53 | 2014-03-05 19:28:09 -0500 | [diff] [blame] | 425 | const struct iovec *iov, unsigned long nr_segs, |
| 426 | size_t count) |
| 427 | { |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 428 | WARN_ON(direction & ~(READ | WRITE)); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 429 | *i = (struct iov_iter) { |
| 430 | .iter_type = ITER_IOVEC, |
Andreas Gruenbacher | 3337ab0 | 2021-07-12 12:06:14 +0200 | [diff] [blame] | 431 | .nofault = false, |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 432 | .user_backed = true, |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 433 | .data_source = direction, |
| 434 | .iov = iov, |
| 435 | .nr_segs = nr_segs, |
| 436 | .iov_offset = 0, |
| 437 | .count = count |
| 438 | }; |
Al Viro | 71d8e53 | 2014-03-05 19:28:09 -0500 | [diff] [blame] | 439 | } |
| 440 | EXPORT_SYMBOL(iov_iter_init); |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 441 | |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 442 | // returns the offset in partial buffer (if any) |
| 443 | static inline unsigned int pipe_npages(const struct iov_iter *i, int *npages) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 444 | { |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 445 | struct pipe_inode_info *pipe = i->pipe; |
| 446 | int used = pipe->head - pipe->tail; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 447 | int off = i->last_offset; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 448 | |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 449 | *npages = max((int)pipe->max_usage - used, 0); |
| 450 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 451 | if (off > 0 && off < PAGE_SIZE) { // anon and not full |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 452 | (*npages)++; |
| 453 | return off; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 454 | } |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 455 | return 0; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 456 | } |
| 457 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 458 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
| 459 | struct iov_iter *i) |
| 460 | { |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 461 | unsigned int off, chunk; |
| 462 | |
| 463 | if (unlikely(bytes > i->count)) |
| 464 | bytes = i->count; |
| 465 | if (unlikely(!bytes)) |
| 466 | return 0; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 467 | |
| 468 | if (!sanity(i)) |
| 469 | return 0; |
| 470 | |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 471 | for (size_t n = bytes; n; n -= chunk) { |
| 472 | struct page *page = append_pipe(i, n, &off); |
| 473 | chunk = min_t(size_t, n, PAGE_SIZE - off); |
| 474 | if (!page) |
| 475 | return bytes - n; |
| 476 | memcpy_to_page(page, off, addr, chunk); |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 477 | addr += chunk; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 478 | } |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 479 | return bytes; |
| 480 | } |
| 481 | |
Al Viro | f915289 | 2018-11-27 22:32:59 -0500 | [diff] [blame] | 482 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
| 483 | __wsum sum, size_t off) |
| 484 | { |
Al Viro | cc44c17 | 2020-07-11 00:12:07 -0400 | [diff] [blame] | 485 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
Al Viro | f915289 | 2018-11-27 22:32:59 -0500 | [diff] [blame] | 486 | return csum_block_add(sum, next, off); |
| 487 | } |
| 488 | |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 489 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 490 | struct iov_iter *i, __wsum *sump) |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 491 | { |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 492 | __wsum sum = *sump; |
| 493 | size_t off = 0; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 494 | unsigned int chunk, r; |
| 495 | |
| 496 | if (unlikely(bytes > i->count)) |
| 497 | bytes = i->count; |
| 498 | if (unlikely(!bytes)) |
| 499 | return 0; |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 500 | |
| 501 | if (!sanity(i)) |
| 502 | return 0; |
| 503 | |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 504 | while (bytes) { |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 505 | struct page *page = append_pipe(i, bytes, &r); |
| 506 | char *p; |
| 507 | |
| 508 | if (!page) |
| 509 | break; |
| 510 | chunk = min_t(size_t, bytes, PAGE_SIZE - r); |
| 511 | p = kmap_local_page(page); |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 512 | sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); |
Al Viro | 2495bdcc | 2021-04-30 13:40:48 -0400 | [diff] [blame] | 513 | kunmap_local(p); |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 514 | off += chunk; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 515 | bytes -= chunk; |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 516 | } |
| 517 | *sump = sum; |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 518 | return off; |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 519 | } |
| 520 | |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 521 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 522 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 523 | if (unlikely(iov_iter_is_pipe(i))) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 524 | return copy_pipe_to_iter(addr, bytes, i); |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 525 | if (user_backed_iter(i)) |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 526 | might_fault(); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 527 | iterate_and_advance(i, bytes, base, len, off, |
| 528 | copyout(base, addr + off, len), |
| 529 | memcpy(base, addr + off, len) |
Al Viro | 3d4d3e4 | 2014-11-27 14:28:06 -0500 | [diff] [blame] | 530 | ) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 531 | |
Al Viro | 3d4d3e4 | 2014-11-27 14:28:06 -0500 | [diff] [blame] | 532 | return bytes; |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 533 | } |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 534 | EXPORT_SYMBOL(_copy_to_iter); |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 535 | |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 536 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
| 537 | static int copyout_mc(void __user *to, const void *from, size_t n) |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 538 | { |
Linus Torvalds | 96d4f26 | 2019-01-03 18:57:57 -0800 | [diff] [blame] | 539 | if (access_ok(to, n)) { |
Marco Elver | d0ef4c3 | 2020-01-21 17:05:11 +0100 | [diff] [blame] | 540 | instrument_copy_to_user(to, from, n); |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 541 | n = copy_mc_to_user((__force void *) to, from, n); |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 542 | } |
| 543 | return n; |
| 544 | } |
| 545 | |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 546 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
Dan Williams | ca146f6 | 2018-07-08 13:46:12 -0700 | [diff] [blame] | 547 | struct iov_iter *i) |
| 548 | { |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 549 | size_t xfer = 0; |
| 550 | unsigned int off, chunk; |
| 551 | |
| 552 | if (unlikely(bytes > i->count)) |
| 553 | bytes = i->count; |
| 554 | if (unlikely(!bytes)) |
| 555 | return 0; |
Dan Williams | ca146f6 | 2018-07-08 13:46:12 -0700 | [diff] [blame] | 556 | |
| 557 | if (!sanity(i)) |
| 558 | return 0; |
| 559 | |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 560 | while (bytes) { |
| 561 | struct page *page = append_pipe(i, bytes, &off); |
Dan Williams | ca146f6 | 2018-07-08 13:46:12 -0700 | [diff] [blame] | 562 | unsigned long rem; |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 563 | char *p; |
| 564 | |
| 565 | if (!page) |
| 566 | break; |
| 567 | chunk = min_t(size_t, bytes, PAGE_SIZE - off); |
| 568 | p = kmap_local_page(page); |
Al Viro | 2a510a7 | 2021-05-02 17:16:34 -0400 | [diff] [blame] | 569 | rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); |
| 570 | chunk -= rem; |
| 571 | kunmap_local(p); |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 572 | xfer += chunk; |
| 573 | bytes -= chunk; |
Al Viro | c3497fd | 2022-06-12 19:50:29 -0400 | [diff] [blame] | 574 | if (rem) { |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 575 | iov_iter_revert(i, rem); |
Dan Williams | ca146f6 | 2018-07-08 13:46:12 -0700 | [diff] [blame] | 576 | break; |
Al Viro | c3497fd | 2022-06-12 19:50:29 -0400 | [diff] [blame] | 577 | } |
Al Viro | 2a510a7 | 2021-05-02 17:16:34 -0400 | [diff] [blame] | 578 | } |
Dan Williams | ca146f6 | 2018-07-08 13:46:12 -0700 | [diff] [blame] | 579 | return xfer; |
| 580 | } |
| 581 | |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 582 | /** |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 583 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 584 | * @addr: source kernel address |
| 585 | * @bytes: total transfer length |
Randy Dunlap | 44e5599 | 2021-09-07 19:58:54 -0700 | [diff] [blame] | 586 | * @i: destination iterator |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 587 | * |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 588 | * The pmem driver deploys this for the dax operation |
| 589 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the |
| 590 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes |
| 591 | * successfully copied. |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 592 | * |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 593 | * The main differences between this and typical _copy_to_iter(). |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 594 | * |
| 595 | * * Typical tail/residue handling after a fault retries the copy |
| 596 | * byte-by-byte until the fault happens again. Re-triggering machine |
| 597 | * checks is potentially fatal so the implementation uses source |
| 598 | * alignment and poison alignment assumptions to avoid re-triggering |
| 599 | * hardware exceptions. |
| 600 | * |
| 601 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. |
| 602 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return |
| 603 | * a short copy. |
Randy Dunlap | 44e5599 | 2021-09-07 19:58:54 -0700 | [diff] [blame] | 604 | * |
| 605 | * Return: number of bytes copied (may be %0) |
Dan Williams | bf3eeb9 | 2018-07-08 13:46:02 -0700 | [diff] [blame] | 606 | */ |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 607 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 608 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 609 | if (unlikely(iov_iter_is_pipe(i))) |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 610 | return copy_mc_pipe_to_iter(addr, bytes, i); |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 611 | if (user_backed_iter(i)) |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 612 | might_fault(); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 613 | __iterate_and_advance(i, bytes, base, len, off, |
| 614 | copyout_mc(base, addr + off, len), |
| 615 | copy_mc_to_kernel(base, addr + off, len) |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 616 | ) |
| 617 | |
| 618 | return bytes; |
| 619 | } |
Dan Williams | ec6347b | 2020-10-05 20:40:16 -0700 | [diff] [blame] | 620 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
| 621 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ |
Dan Williams | 8780356 | 2018-05-03 17:06:31 -0700 | [diff] [blame] | 622 | |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 623 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 624 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 625 | if (unlikely(iov_iter_is_pipe(i))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 626 | WARN_ON(1); |
| 627 | return 0; |
| 628 | } |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 629 | if (user_backed_iter(i)) |
Al Viro | 09fc68dc | 2017-06-29 22:25:14 -0400 | [diff] [blame] | 630 | might_fault(); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 631 | iterate_and_advance(i, bytes, base, len, off, |
| 632 | copyin(addr + off, base, len), |
| 633 | memcpy(addr + off, base, len) |
Al Viro | 0dbca9a | 2014-11-27 14:26:43 -0500 | [diff] [blame] | 634 | ) |
| 635 | |
| 636 | return bytes; |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 637 | } |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 638 | EXPORT_SYMBOL(_copy_from_iter); |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 639 | |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 640 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
Al Viro | aa58309 | 2014-11-27 20:27:08 -0500 | [diff] [blame] | 641 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 642 | if (unlikely(iov_iter_is_pipe(i))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 643 | WARN_ON(1); |
| 644 | return 0; |
| 645 | } |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 646 | iterate_and_advance(i, bytes, base, len, off, |
| 647 | __copy_from_user_inatomic_nocache(addr + off, base, len), |
| 648 | memcpy(addr + off, base, len) |
Al Viro | aa58309 | 2014-11-27 20:27:08 -0500 | [diff] [blame] | 649 | ) |
| 650 | |
| 651 | return bytes; |
| 652 | } |
Al Viro | aa28de2 | 2017-06-29 21:45:10 -0400 | [diff] [blame] | 653 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
Al Viro | aa58309 | 2014-11-27 20:27:08 -0500 | [diff] [blame] | 654 | |
Dan Williams | 0aed55a | 2017-05-29 12:22:50 -0700 | [diff] [blame] | 655 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
Dan Williams | abd08d7 | 2018-07-08 13:46:07 -0700 | [diff] [blame] | 656 | /** |
| 657 | * _copy_from_iter_flushcache - write destination through cpu cache |
| 658 | * @addr: destination kernel address |
| 659 | * @bytes: total transfer length |
Randy Dunlap | 44e5599 | 2021-09-07 19:58:54 -0700 | [diff] [blame] | 660 | * @i: source iterator |
Dan Williams | abd08d7 | 2018-07-08 13:46:07 -0700 | [diff] [blame] | 661 | * |
| 662 | * The pmem driver arranges for filesystem-dax to use this facility via |
| 663 | * dax_copy_from_iter() for ensuring that writes to persistent memory |
| 664 | * are flushed through the CPU cache. It is differentiated from |
| 665 | * _copy_from_iter_nocache() in that guarantees all data is flushed for |
| 666 | * all iterator types. The _copy_from_iter_nocache() only attempts to |
| 667 | * bypass the cache for the ITER_IOVEC case, and on some archs may use |
| 668 | * instructions that strand dirty-data in the cache. |
Randy Dunlap | 44e5599 | 2021-09-07 19:58:54 -0700 | [diff] [blame] | 669 | * |
| 670 | * Return: number of bytes copied (may be %0) |
Dan Williams | abd08d7 | 2018-07-08 13:46:07 -0700 | [diff] [blame] | 671 | */ |
Linus Torvalds | 6a37e94 | 2017-07-07 20:39:20 -0700 | [diff] [blame] | 672 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
Dan Williams | 0aed55a | 2017-05-29 12:22:50 -0700 | [diff] [blame] | 673 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 674 | if (unlikely(iov_iter_is_pipe(i))) { |
Dan Williams | 0aed55a | 2017-05-29 12:22:50 -0700 | [diff] [blame] | 675 | WARN_ON(1); |
| 676 | return 0; |
| 677 | } |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 678 | iterate_and_advance(i, bytes, base, len, off, |
| 679 | __copy_from_user_flushcache(addr + off, base, len), |
| 680 | memcpy_flushcache(addr + off, base, len) |
Dan Williams | 0aed55a | 2017-05-29 12:22:50 -0700 | [diff] [blame] | 681 | ) |
| 682 | |
| 683 | return bytes; |
| 684 | } |
Linus Torvalds | 6a37e94 | 2017-07-07 20:39:20 -0700 | [diff] [blame] | 685 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
Dan Williams | 0aed55a | 2017-05-29 12:22:50 -0700 | [diff] [blame] | 686 | #endif |
| 687 | |
Al Viro | 72e809e | 2017-06-29 21:52:57 -0400 | [diff] [blame] | 688 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
| 689 | { |
Eric Dumazet | 6daef95 | 2019-02-26 10:42:39 -0800 | [diff] [blame] | 690 | struct page *head; |
| 691 | size_t v = n + offset; |
| 692 | |
| 693 | /* |
| 694 | * The general case needs to access the page order in order |
| 695 | * to compute the page size. |
| 696 | * However, we mostly deal with order-0 pages and thus can |
| 697 | * avoid a possible cache line miss for requests that fit all |
| 698 | * page orders. |
| 699 | */ |
| 700 | if (n <= v && v <= PAGE_SIZE) |
| 701 | return true; |
| 702 | |
| 703 | head = compound_head(page); |
| 704 | v += (page - head) << PAGE_SHIFT; |
Petar Penkov | a90bcb8 | 2017-08-29 11:20:32 -0700 | [diff] [blame] | 705 | |
Matthew Wilcox (Oracle) | a50b854 | 2019-09-23 15:34:25 -0700 | [diff] [blame] | 706 | if (likely(n <= v && v <= (page_size(head)))) |
Al Viro | 72e809e | 2017-06-29 21:52:57 -0400 | [diff] [blame] | 707 | return true; |
| 708 | WARN_ON(1); |
| 709 | return false; |
| 710 | } |
Al Viro | cbbd26b | 2016-11-01 22:09:04 -0400 | [diff] [blame] | 711 | |
Al Viro | 08aa647 | 2021-04-29 20:42:25 -0400 | [diff] [blame] | 712 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
| 713 | struct iov_iter *i) |
| 714 | { |
| 715 | size_t res = 0; |
| 716 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
| 717 | return 0; |
Al Viro | f0f6b61 | 2022-06-23 17:21:37 -0400 | [diff] [blame] | 718 | if (unlikely(iov_iter_is_pipe(i))) |
| 719 | return copy_page_to_iter_pipe(page, offset, bytes, i); |
Al Viro | 08aa647 | 2021-04-29 20:42:25 -0400 | [diff] [blame] | 720 | page += offset / PAGE_SIZE; // first subpage |
| 721 | offset %= PAGE_SIZE; |
| 722 | while (1) { |
Al Viro | f0f6b61 | 2022-06-23 17:21:37 -0400 | [diff] [blame] | 723 | void *kaddr = kmap_local_page(page); |
| 724 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
| 725 | n = _copy_to_iter(kaddr + offset, n, i); |
| 726 | kunmap_local(kaddr); |
Al Viro | 08aa647 | 2021-04-29 20:42:25 -0400 | [diff] [blame] | 727 | res += n; |
| 728 | bytes -= n; |
| 729 | if (!bytes || !n) |
| 730 | break; |
| 731 | offset += n; |
| 732 | if (offset == PAGE_SIZE) { |
| 733 | page++; |
| 734 | offset = 0; |
| 735 | } |
| 736 | } |
| 737 | return res; |
| 738 | } |
Al Viro | d271524 | 2014-11-27 14:22:37 -0500 | [diff] [blame] | 739 | EXPORT_SYMBOL(copy_page_to_iter); |
| 740 | |
| 741 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
| 742 | struct iov_iter *i) |
| 743 | { |
Al Viro | c03f05f | 2022-07-29 12:54:53 -0400 | [diff] [blame] | 744 | size_t res = 0; |
| 745 | if (!page_copy_sane(page, offset, bytes)) |
| 746 | return 0; |
| 747 | page += offset / PAGE_SIZE; // first subpage |
| 748 | offset %= PAGE_SIZE; |
| 749 | while (1) { |
Al Viro | 55ca375 | 2021-04-27 12:33:24 -0400 | [diff] [blame] | 750 | void *kaddr = kmap_local_page(page); |
Al Viro | c03f05f | 2022-07-29 12:54:53 -0400 | [diff] [blame] | 751 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
| 752 | n = _copy_from_iter(kaddr + offset, n, i); |
Al Viro | 55ca375 | 2021-04-27 12:33:24 -0400 | [diff] [blame] | 753 | kunmap_local(kaddr); |
Al Viro | c03f05f | 2022-07-29 12:54:53 -0400 | [diff] [blame] | 754 | res += n; |
| 755 | bytes -= n; |
| 756 | if (!bytes || !n) |
| 757 | break; |
| 758 | offset += n; |
| 759 | if (offset == PAGE_SIZE) { |
| 760 | page++; |
| 761 | offset = 0; |
| 762 | } |
Al Viro | 28f38db | 2021-06-02 17:25:59 -0400 | [diff] [blame] | 763 | } |
Al Viro | c03f05f | 2022-07-29 12:54:53 -0400 | [diff] [blame] | 764 | return res; |
Al Viro | d271524 | 2014-11-27 14:22:37 -0500 | [diff] [blame] | 765 | } |
| 766 | EXPORT_SYMBOL(copy_page_from_iter); |
| 767 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 768 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
| 769 | { |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 770 | unsigned int chunk, off; |
| 771 | |
| 772 | if (unlikely(bytes > i->count)) |
| 773 | bytes = i->count; |
| 774 | if (unlikely(!bytes)) |
| 775 | return 0; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 776 | |
| 777 | if (!sanity(i)) |
| 778 | return 0; |
| 779 | |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 780 | for (size_t n = bytes; n; n -= chunk) { |
| 781 | struct page *page = append_pipe(i, n, &off); |
| 782 | char *p; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 783 | |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 784 | if (!page) |
| 785 | return bytes - n; |
| 786 | chunk = min_t(size_t, n, PAGE_SIZE - off); |
| 787 | p = kmap_local_page(page); |
Al Viro | 893839f | 2021-04-30 18:39:25 -0400 | [diff] [blame] | 788 | memset(p + off, 0, chunk); |
| 789 | kunmap_local(p); |
Al Viro | 8fad776 | 2022-06-14 13:53:53 -0400 | [diff] [blame] | 790 | } |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 791 | return bytes; |
| 792 | } |
| 793 | |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 794 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
| 795 | { |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 796 | if (unlikely(iov_iter_is_pipe(i))) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 797 | return pipe_zero(bytes, i); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 798 | iterate_and_advance(i, bytes, base, len, count, |
| 799 | clear_user(base, len), |
| 800 | memset(base, 0, len) |
Al Viro | 8442fa4 | 2014-11-27 14:18:54 -0500 | [diff] [blame] | 801 | ) |
| 802 | |
| 803 | return bytes; |
Matthew Wilcox | c35e024 | 2014-08-01 09:27:22 -0400 | [diff] [blame] | 804 | } |
| 805 | EXPORT_SYMBOL(iov_iter_zero); |
| 806 | |
Al Viro | f0b65f3 | 2021-04-30 10:26:41 -0400 | [diff] [blame] | 807 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
| 808 | struct iov_iter *i) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 809 | { |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 810 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
Al Viro | 72e809e | 2017-06-29 21:52:57 -0400 | [diff] [blame] | 811 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
| 812 | kunmap_atomic(kaddr); |
| 813 | return 0; |
| 814 | } |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 815 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 816 | kunmap_atomic(kaddr); |
| 817 | WARN_ON(1); |
| 818 | return 0; |
| 819 | } |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 820 | iterate_and_advance(i, bytes, base, len, off, |
| 821 | copyin(p + off, base, len), |
| 822 | memcpy(p + off, base, len) |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 823 | ) |
| 824 | kunmap_atomic(kaddr); |
| 825 | return bytes; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 826 | } |
Al Viro | f0b65f3 | 2021-04-30 10:26:41 -0400 | [diff] [blame] | 827 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 828 | |
Al Viro | b9dc6f6 | 2017-01-14 19:33:08 -0500 | [diff] [blame] | 829 | static void pipe_advance(struct iov_iter *i, size_t size) |
| 830 | { |
| 831 | struct pipe_inode_info *pipe = i->pipe; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 832 | int off = i->last_offset; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 833 | |
Al Viro | 2c855de | 2022-06-15 16:03:25 -0400 | [diff] [blame] | 834 | if (!off && !size) { |
| 835 | pipe_discard_from(pipe, i->start_head); // discard everything |
| 836 | return; |
Al Viro | b9dc6f6 | 2017-01-14 19:33:08 -0500 | [diff] [blame] | 837 | } |
| 838 | i->count -= size; |
Al Viro | 2c855de | 2022-06-15 16:03:25 -0400 | [diff] [blame] | 839 | while (1) { |
| 840 | struct pipe_buffer *buf = pipe_buf(pipe, i->head); |
| 841 | if (off) /* make it relative to the beginning of buffer */ |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 842 | size += abs(off) - buf->offset; |
Al Viro | 2c855de | 2022-06-15 16:03:25 -0400 | [diff] [blame] | 843 | if (size <= buf->len) { |
| 844 | buf->len = size; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 845 | i->last_offset = last_offset(buf); |
Al Viro | 2c855de | 2022-06-15 16:03:25 -0400 | [diff] [blame] | 846 | break; |
| 847 | } |
| 848 | size -= buf->len; |
| 849 | i->head++; |
| 850 | off = 0; |
| 851 | } |
| 852 | pipe_discard_from(pipe, i->head + 1); // discard everything past this one |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 853 | } |
| 854 | |
Pavel Begunkov | 54c8195 | 2021-01-09 16:03:01 +0000 | [diff] [blame] | 855 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
| 856 | { |
Al Viro | 18fa9af | 2022-06-06 23:44:33 -0400 | [diff] [blame] | 857 | const struct bio_vec *bvec, *end; |
Pavel Begunkov | 54c8195 | 2021-01-09 16:03:01 +0000 | [diff] [blame] | 858 | |
Al Viro | 18fa9af | 2022-06-06 23:44:33 -0400 | [diff] [blame] | 859 | if (!i->count) |
| 860 | return; |
| 861 | i->count -= size; |
Pavel Begunkov | 54c8195 | 2021-01-09 16:03:01 +0000 | [diff] [blame] | 862 | |
Al Viro | 18fa9af | 2022-06-06 23:44:33 -0400 | [diff] [blame] | 863 | size += i->iov_offset; |
| 864 | |
| 865 | for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { |
| 866 | if (likely(size < bvec->bv_len)) |
| 867 | break; |
| 868 | size -= bvec->bv_len; |
| 869 | } |
| 870 | i->iov_offset = size; |
| 871 | i->nr_segs -= bvec - i->bvec; |
| 872 | i->bvec = bvec; |
Pavel Begunkov | 54c8195 | 2021-01-09 16:03:01 +0000 | [diff] [blame] | 873 | } |
| 874 | |
Al Viro | 185ac4d | 2021-04-23 12:58:53 -0400 | [diff] [blame] | 875 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
| 876 | { |
| 877 | const struct iovec *iov, *end; |
| 878 | |
| 879 | if (!i->count) |
| 880 | return; |
| 881 | i->count -= size; |
| 882 | |
| 883 | size += i->iov_offset; // from beginning of current segment |
| 884 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { |
| 885 | if (likely(size < iov->iov_len)) |
| 886 | break; |
| 887 | size -= iov->iov_len; |
| 888 | } |
| 889 | i->iov_offset = size; |
| 890 | i->nr_segs -= iov - i->iov; |
| 891 | i->iov = iov; |
| 892 | } |
| 893 | |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 894 | void iov_iter_advance(struct iov_iter *i, size_t size) |
| 895 | { |
Al Viro | 3b3fc05 | 2021-04-23 22:24:08 -0400 | [diff] [blame] | 896 | if (unlikely(i->count < size)) |
| 897 | size = i->count; |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 898 | if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { |
| 899 | i->iov_offset += size; |
| 900 | i->count -= size; |
| 901 | } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
Al Viro | 185ac4d | 2021-04-23 12:58:53 -0400 | [diff] [blame] | 902 | /* iovec and kvec have identical layouts */ |
| 903 | iov_iter_iovec_advance(i, size); |
| 904 | } else if (iov_iter_is_bvec(i)) { |
| 905 | iov_iter_bvec_advance(i, size); |
| 906 | } else if (iov_iter_is_pipe(i)) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 907 | pipe_advance(i, size); |
Al Viro | 185ac4d | 2021-04-23 12:58:53 -0400 | [diff] [blame] | 908 | } else if (iov_iter_is_discard(i)) { |
| 909 | i->count -= size; |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 910 | } |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 911 | } |
| 912 | EXPORT_SYMBOL(iov_iter_advance); |
| 913 | |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 914 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
| 915 | { |
| 916 | if (!unroll) |
| 917 | return; |
Al Viro | 5b47d59 | 2017-05-08 13:54:47 -0400 | [diff] [blame] | 918 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
| 919 | return; |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 920 | i->count += unroll; |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 921 | if (unlikely(iov_iter_is_pipe(i))) { |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 922 | struct pipe_inode_info *pipe = i->pipe; |
Al Viro | 92acdc4 | 2022-06-12 17:54:35 -0400 | [diff] [blame] | 923 | unsigned int head = pipe->head; |
| 924 | |
| 925 | while (head > i->start_head) { |
| 926 | struct pipe_buffer *b = pipe_buf(pipe, --head); |
| 927 | if (unroll < b->len) { |
| 928 | b->len -= unroll; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 929 | i->last_offset = last_offset(b); |
Al Viro | 92acdc4 | 2022-06-12 17:54:35 -0400 | [diff] [blame] | 930 | i->head = head; |
| 931 | return; |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 932 | } |
Al Viro | 92acdc4 | 2022-06-12 17:54:35 -0400 | [diff] [blame] | 933 | unroll -= b->len; |
| 934 | pipe_buf_release(pipe, b); |
| 935 | pipe->head--; |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 936 | } |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 937 | i->last_offset = 0; |
Al Viro | 92acdc4 | 2022-06-12 17:54:35 -0400 | [diff] [blame] | 938 | i->head = head; |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 939 | return; |
| 940 | } |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 941 | if (unlikely(iov_iter_is_discard(i))) |
| 942 | return; |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 943 | if (unroll <= i->iov_offset) { |
| 944 | i->iov_offset -= unroll; |
| 945 | return; |
| 946 | } |
| 947 | unroll -= i->iov_offset; |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 948 | if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 949 | BUG(); /* We should never go beyond the start of the specified |
| 950 | * range since we might then be straying into pages that |
| 951 | * aren't pinned. |
| 952 | */ |
| 953 | } else if (iov_iter_is_bvec(i)) { |
Al Viro | 27c0e37 | 2017-02-17 18:42:24 -0500 | [diff] [blame] | 954 | const struct bio_vec *bvec = i->bvec; |
| 955 | while (1) { |
| 956 | size_t n = (--bvec)->bv_len; |
| 957 | i->nr_segs++; |
| 958 | if (unroll <= n) { |
| 959 | i->bvec = bvec; |
| 960 | i->iov_offset = n - unroll; |
| 961 | return; |
| 962 | } |
| 963 | unroll -= n; |
| 964 | } |
| 965 | } else { /* same logics for iovec and kvec */ |
| 966 | const struct iovec *iov = i->iov; |
| 967 | while (1) { |
| 968 | size_t n = (--iov)->iov_len; |
| 969 | i->nr_segs++; |
| 970 | if (unroll <= n) { |
| 971 | i->iov = iov; |
| 972 | i->iov_offset = n - unroll; |
| 973 | return; |
| 974 | } |
| 975 | unroll -= n; |
| 976 | } |
| 977 | } |
| 978 | } |
| 979 | EXPORT_SYMBOL(iov_iter_revert); |
| 980 | |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 981 | /* |
| 982 | * Return the count of just the current iov_iter segment. |
| 983 | */ |
| 984 | size_t iov_iter_single_seg_count(const struct iov_iter *i) |
| 985 | { |
Al Viro | 28f38db | 2021-06-02 17:25:59 -0400 | [diff] [blame] | 986 | if (i->nr_segs > 1) { |
| 987 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
| 988 | return min(i->count, i->iov->iov_len - i->iov_offset); |
| 989 | if (iov_iter_is_bvec(i)) |
| 990 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
| 991 | } |
| 992 | return i->count; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 993 | } |
| 994 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
| 995 | |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 996 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
Al Viro | 05afcb7 | 2015-01-23 01:08:07 -0500 | [diff] [blame] | 997 | const struct kvec *kvec, unsigned long nr_segs, |
Al Viro | abb78f8 | 2014-11-24 14:46:11 -0500 | [diff] [blame] | 998 | size_t count) |
| 999 | { |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1000 | WARN_ON(direction & ~(READ | WRITE)); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1001 | *i = (struct iov_iter){ |
| 1002 | .iter_type = ITER_KVEC, |
| 1003 | .data_source = direction, |
| 1004 | .kvec = kvec, |
| 1005 | .nr_segs = nr_segs, |
| 1006 | .iov_offset = 0, |
| 1007 | .count = count |
| 1008 | }; |
Al Viro | abb78f8 | 2014-11-24 14:46:11 -0500 | [diff] [blame] | 1009 | } |
| 1010 | EXPORT_SYMBOL(iov_iter_kvec); |
| 1011 | |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1012 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
Al Viro | 05afcb7 | 2015-01-23 01:08:07 -0500 | [diff] [blame] | 1013 | const struct bio_vec *bvec, unsigned long nr_segs, |
| 1014 | size_t count) |
| 1015 | { |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1016 | WARN_ON(direction & ~(READ | WRITE)); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1017 | *i = (struct iov_iter){ |
| 1018 | .iter_type = ITER_BVEC, |
| 1019 | .data_source = direction, |
| 1020 | .bvec = bvec, |
| 1021 | .nr_segs = nr_segs, |
| 1022 | .iov_offset = 0, |
| 1023 | .count = count |
| 1024 | }; |
Al Viro | 05afcb7 | 2015-01-23 01:08:07 -0500 | [diff] [blame] | 1025 | } |
| 1026 | EXPORT_SYMBOL(iov_iter_bvec); |
| 1027 | |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1028 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1029 | struct pipe_inode_info *pipe, |
| 1030 | size_t count) |
| 1031 | { |
David Howells | aa563d7 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1032 | BUG_ON(direction != READ); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1033 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1034 | *i = (struct iov_iter){ |
| 1035 | .iter_type = ITER_PIPE, |
| 1036 | .data_source = false, |
| 1037 | .pipe = pipe, |
| 1038 | .head = pipe->head, |
| 1039 | .start_head = pipe->head, |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 1040 | .last_offset = 0, |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1041 | .count = count |
| 1042 | }; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1043 | } |
| 1044 | EXPORT_SYMBOL(iov_iter_pipe); |
| 1045 | |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1046 | /** |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1047 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray |
| 1048 | * @i: The iterator to initialise. |
| 1049 | * @direction: The direction of the transfer. |
| 1050 | * @xarray: The xarray to access. |
| 1051 | * @start: The start file position. |
| 1052 | * @count: The size of the I/O buffer in bytes. |
| 1053 | * |
| 1054 | * Set up an I/O iterator to either draw data out of the pages attached to an |
| 1055 | * inode or to inject data into those pages. The pages *must* be prevented |
| 1056 | * from evaporation, either by taking a ref on them or locking them by the |
| 1057 | * caller. |
| 1058 | */ |
| 1059 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, |
| 1060 | struct xarray *xarray, loff_t start, size_t count) |
| 1061 | { |
| 1062 | BUG_ON(direction & ~1); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1063 | *i = (struct iov_iter) { |
| 1064 | .iter_type = ITER_XARRAY, |
| 1065 | .data_source = direction, |
| 1066 | .xarray = xarray, |
| 1067 | .xarray_start = start, |
| 1068 | .count = count, |
| 1069 | .iov_offset = 0 |
| 1070 | }; |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1071 | } |
| 1072 | EXPORT_SYMBOL(iov_iter_xarray); |
| 1073 | |
| 1074 | /** |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1075 | * iov_iter_discard - Initialise an I/O iterator that discards data |
| 1076 | * @i: The iterator to initialise. |
| 1077 | * @direction: The direction of the transfer. |
| 1078 | * @count: The size of the I/O buffer in bytes. |
| 1079 | * |
| 1080 | * Set up an I/O iterator that just discards everything that's written to it. |
| 1081 | * It's only available as a READ iterator. |
| 1082 | */ |
| 1083 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) |
| 1084 | { |
| 1085 | BUG_ON(direction != READ); |
Al Viro | 8cd54c1 | 2021-04-22 14:50:39 -0400 | [diff] [blame] | 1086 | *i = (struct iov_iter){ |
| 1087 | .iter_type = ITER_DISCARD, |
| 1088 | .data_source = false, |
| 1089 | .count = count, |
| 1090 | .iov_offset = 0 |
| 1091 | }; |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1092 | } |
| 1093 | EXPORT_SYMBOL(iov_iter_discard); |
| 1094 | |
Keith Busch | cfa320f | 2022-06-10 12:58:27 -0700 | [diff] [blame] | 1095 | static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, |
| 1096 | unsigned len_mask) |
| 1097 | { |
| 1098 | size_t size = i->count; |
| 1099 | size_t skip = i->iov_offset; |
| 1100 | unsigned k; |
| 1101 | |
| 1102 | for (k = 0; k < i->nr_segs; k++, skip = 0) { |
| 1103 | size_t len = i->iov[k].iov_len - skip; |
| 1104 | |
| 1105 | if (len > size) |
| 1106 | len = size; |
| 1107 | if (len & len_mask) |
| 1108 | return false; |
| 1109 | if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask) |
| 1110 | return false; |
| 1111 | |
| 1112 | size -= len; |
| 1113 | if (!size) |
| 1114 | break; |
| 1115 | } |
| 1116 | return true; |
| 1117 | } |
| 1118 | |
| 1119 | static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, |
| 1120 | unsigned len_mask) |
| 1121 | { |
| 1122 | size_t size = i->count; |
| 1123 | unsigned skip = i->iov_offset; |
| 1124 | unsigned k; |
| 1125 | |
| 1126 | for (k = 0; k < i->nr_segs; k++, skip = 0) { |
| 1127 | size_t len = i->bvec[k].bv_len - skip; |
| 1128 | |
| 1129 | if (len > size) |
| 1130 | len = size; |
| 1131 | if (len & len_mask) |
| 1132 | return false; |
| 1133 | if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask) |
| 1134 | return false; |
| 1135 | |
| 1136 | size -= len; |
| 1137 | if (!size) |
| 1138 | break; |
| 1139 | } |
| 1140 | return true; |
| 1141 | } |
| 1142 | |
| 1143 | /** |
| 1144 | * iov_iter_is_aligned() - Check if the addresses and lengths of each segments |
| 1145 | * are aligned to the parameters. |
| 1146 | * |
| 1147 | * @i: &struct iov_iter to restore |
| 1148 | * @addr_mask: bit mask to check against the iov element's addresses |
| 1149 | * @len_mask: bit mask to check against the iov element's lengths |
| 1150 | * |
| 1151 | * Return: false if any addresses or lengths intersect with the provided masks |
| 1152 | */ |
| 1153 | bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, |
| 1154 | unsigned len_mask) |
| 1155 | { |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1156 | if (likely(iter_is_ubuf(i))) { |
| 1157 | if (i->count & len_mask) |
| 1158 | return false; |
| 1159 | if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) |
| 1160 | return false; |
| 1161 | return true; |
| 1162 | } |
| 1163 | |
Keith Busch | cfa320f | 2022-06-10 12:58:27 -0700 | [diff] [blame] | 1164 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
| 1165 | return iov_iter_aligned_iovec(i, addr_mask, len_mask); |
| 1166 | |
| 1167 | if (iov_iter_is_bvec(i)) |
| 1168 | return iov_iter_aligned_bvec(i, addr_mask, len_mask); |
| 1169 | |
| 1170 | if (iov_iter_is_pipe(i)) { |
Keith Busch | cfa320f | 2022-06-10 12:58:27 -0700 | [diff] [blame] | 1171 | size_t size = i->count; |
| 1172 | |
| 1173 | if (size & len_mask) |
| 1174 | return false; |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 1175 | if (size && i->last_offset > 0) { |
| 1176 | if (i->last_offset & addr_mask) |
Keith Busch | cfa320f | 2022-06-10 12:58:27 -0700 | [diff] [blame] | 1177 | return false; |
| 1178 | } |
| 1179 | |
| 1180 | return true; |
| 1181 | } |
| 1182 | |
| 1183 | if (iov_iter_is_xarray(i)) { |
| 1184 | if (i->count & len_mask) |
| 1185 | return false; |
| 1186 | if ((i->xarray_start + i->iov_offset) & addr_mask) |
| 1187 | return false; |
| 1188 | } |
| 1189 | |
| 1190 | return true; |
| 1191 | } |
| 1192 | EXPORT_SYMBOL_GPL(iov_iter_is_aligned); |
| 1193 | |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1194 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1195 | { |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 1196 | unsigned long res = 0; |
| 1197 | size_t size = i->count; |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1198 | size_t skip = i->iov_offset; |
| 1199 | unsigned k; |
Al Viro | 04a3116 | 2014-11-27 13:51:41 -0500 | [diff] [blame] | 1200 | |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1201 | for (k = 0; k < i->nr_segs; k++, skip = 0) { |
| 1202 | size_t len = i->iov[k].iov_len - skip; |
| 1203 | if (len) { |
| 1204 | res |= (unsigned long)i->iov[k].iov_base + skip; |
| 1205 | if (len > size) |
| 1206 | len = size; |
| 1207 | res |= len; |
| 1208 | size -= len; |
| 1209 | if (!size) |
| 1210 | break; |
| 1211 | } |
| 1212 | } |
| 1213 | return res; |
| 1214 | } |
| 1215 | |
| 1216 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
| 1217 | { |
| 1218 | unsigned res = 0; |
| 1219 | size_t size = i->count; |
| 1220 | unsigned skip = i->iov_offset; |
| 1221 | unsigned k; |
| 1222 | |
| 1223 | for (k = 0; k < i->nr_segs; k++, skip = 0) { |
| 1224 | size_t len = i->bvec[k].bv_len - skip; |
| 1225 | res |= (unsigned long)i->bvec[k].bv_offset + skip; |
| 1226 | if (len > size) |
| 1227 | len = size; |
| 1228 | res |= len; |
| 1229 | size -= len; |
| 1230 | if (!size) |
| 1231 | break; |
| 1232 | } |
| 1233 | return res; |
| 1234 | } |
| 1235 | |
| 1236 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
| 1237 | { |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1238 | if (likely(iter_is_ubuf(i))) { |
| 1239 | size_t size = i->count; |
| 1240 | if (size) |
| 1241 | return ((unsigned long)i->ubuf + i->iov_offset) | size; |
| 1242 | return 0; |
| 1243 | } |
| 1244 | |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1245 | /* iovec and kvec have identical layouts */ |
| 1246 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
| 1247 | return iov_iter_alignment_iovec(i); |
| 1248 | |
| 1249 | if (iov_iter_is_bvec(i)) |
| 1250 | return iov_iter_alignment_bvec(i); |
| 1251 | |
| 1252 | if (iov_iter_is_pipe(i)) { |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1253 | size_t size = i->count; |
Jan Kara | e0ff126 | 2019-12-16 11:54:32 +0100 | [diff] [blame] | 1254 | |
Al Viro | 10f525a | 2022-06-15 02:02:51 -0400 | [diff] [blame] | 1255 | if (size && i->last_offset > 0) |
| 1256 | return size | i->last_offset; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1257 | return size; |
| 1258 | } |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1259 | |
| 1260 | if (iov_iter_is_xarray(i)) |
David Howells | 3d14ec1 | 2021-04-25 22:02:38 +0100 | [diff] [blame] | 1261 | return (i->xarray_start + i->iov_offset) | i->count; |
Al Viro | 9221d2e | 2021-04-25 00:44:35 -0400 | [diff] [blame] | 1262 | |
| 1263 | return 0; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1264 | } |
| 1265 | EXPORT_SYMBOL(iov_iter_alignment); |
| 1266 | |
Al Viro | 357f435 | 2016-04-08 19:05:19 -0400 | [diff] [blame] | 1267 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
| 1268 | { |
Al Viro | 33844e6 | 2016-12-21 21:55:02 -0500 | [diff] [blame] | 1269 | unsigned long res = 0; |
Al Viro | 610c7a7 | 2021-04-25 01:03:16 -0400 | [diff] [blame] | 1270 | unsigned long v = 0; |
Al Viro | 357f435 | 2016-04-08 19:05:19 -0400 | [diff] [blame] | 1271 | size_t size = i->count; |
Al Viro | 610c7a7 | 2021-04-25 01:03:16 -0400 | [diff] [blame] | 1272 | unsigned k; |
Al Viro | 357f435 | 2016-04-08 19:05:19 -0400 | [diff] [blame] | 1273 | |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1274 | if (iter_is_ubuf(i)) |
| 1275 | return 0; |
| 1276 | |
Al Viro | 610c7a7 | 2021-04-25 01:03:16 -0400 | [diff] [blame] | 1277 | if (WARN_ON(!iter_is_iovec(i))) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1278 | return ~0U; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1279 | |
Al Viro | 610c7a7 | 2021-04-25 01:03:16 -0400 | [diff] [blame] | 1280 | for (k = 0; k < i->nr_segs; k++) { |
| 1281 | if (i->iov[k].iov_len) { |
| 1282 | unsigned long base = (unsigned long)i->iov[k].iov_base; |
| 1283 | if (v) // if not the first one |
| 1284 | res |= base | v; // this start | previous end |
| 1285 | v = base + i->iov[k].iov_len; |
| 1286 | if (size <= i->iov[k].iov_len) |
| 1287 | break; |
| 1288 | size -= i->iov[k].iov_len; |
| 1289 | } |
| 1290 | } |
Al Viro | 33844e6 | 2016-12-21 21:55:02 -0500 | [diff] [blame] | 1291 | return res; |
Al Viro | 357f435 | 2016-04-08 19:05:19 -0400 | [diff] [blame] | 1292 | } |
| 1293 | EXPORT_SYMBOL(iov_iter_gap_alignment); |
| 1294 | |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1295 | static int want_pages_array(struct page ***res, size_t size, |
| 1296 | size_t start, unsigned int maxpages) |
Al Viro | acbdeb8 | 2022-06-17 13:35:35 -0400 | [diff] [blame] | 1297 | { |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1298 | unsigned int count = DIV_ROUND_UP(size + start, PAGE_SIZE); |
| 1299 | |
| 1300 | if (count > maxpages) |
| 1301 | count = maxpages; |
| 1302 | WARN_ON(!count); // caller should've prevented that |
| 1303 | if (!*res) { |
| 1304 | *res = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL); |
| 1305 | if (!*res) |
| 1306 | return 0; |
| 1307 | } |
| 1308 | return count; |
Al Viro | acbdeb8 | 2022-06-17 13:35:35 -0400 | [diff] [blame] | 1309 | } |
| 1310 | |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1311 | static ssize_t pipe_get_pages(struct iov_iter *i, |
| 1312 | struct page ***pages, size_t maxsize, unsigned maxpages, |
| 1313 | size_t *start) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1314 | { |
Al Viro | 746de1f | 2022-06-14 16:38:53 -0400 | [diff] [blame] | 1315 | unsigned int npages, count, off, chunk; |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1316 | struct page **p; |
Al Viro | 746de1f | 2022-06-14 16:38:53 -0400 | [diff] [blame] | 1317 | size_t left; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1318 | |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1319 | if (!sanity(i)) |
| 1320 | return -EFAULT; |
| 1321 | |
| 1322 | *start = off = pipe_npages(i, &npages); |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1323 | if (!npages) |
| 1324 | return -EFAULT; |
| 1325 | count = want_pages_array(pages, maxsize, off, min(npages, maxpages)); |
| 1326 | if (!count) |
| 1327 | return -ENOMEM; |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1328 | p = *pages; |
Al Viro | 746de1f | 2022-06-14 16:38:53 -0400 | [diff] [blame] | 1329 | for (npages = 0, left = maxsize ; npages < count; npages++, left -= chunk) { |
| 1330 | struct page *page = append_pipe(i, left, &off); |
Al Viro | e3b4296 | 2022-06-11 02:52:03 -0400 | [diff] [blame] | 1331 | if (!page) |
| 1332 | break; |
Al Viro | 746de1f | 2022-06-14 16:38:53 -0400 | [diff] [blame] | 1333 | chunk = min_t(size_t, left, PAGE_SIZE - off); |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1334 | get_page(*p++ = page); |
Al Viro | e3b4296 | 2022-06-11 02:52:03 -0400 | [diff] [blame] | 1335 | } |
Al Viro | 8520008 | 2022-06-17 14:30:39 -0400 | [diff] [blame] | 1336 | if (!npages) |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1337 | return -EFAULT; |
Al Viro | 746de1f | 2022-06-14 16:38:53 -0400 | [diff] [blame] | 1338 | return maxsize - left; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1339 | } |
| 1340 | |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1341 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
| 1342 | pgoff_t index, unsigned int nr_pages) |
| 1343 | { |
| 1344 | XA_STATE(xas, xa, index); |
| 1345 | struct page *page; |
| 1346 | unsigned int ret = 0; |
| 1347 | |
| 1348 | rcu_read_lock(); |
| 1349 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { |
| 1350 | if (xas_retry(&xas, page)) |
| 1351 | continue; |
| 1352 | |
| 1353 | /* Has the page moved or been split? */ |
| 1354 | if (unlikely(page != xas_reload(&xas))) { |
| 1355 | xas_reset(&xas); |
| 1356 | continue; |
| 1357 | } |
| 1358 | |
| 1359 | pages[ret] = find_subpage(page, xas.xa_index); |
| 1360 | get_page(pages[ret]); |
| 1361 | if (++ret == nr_pages) |
| 1362 | break; |
| 1363 | } |
| 1364 | rcu_read_unlock(); |
| 1365 | return ret; |
| 1366 | } |
| 1367 | |
| 1368 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, |
Al Viro | 68fe506 | 2022-06-17 13:48:03 -0400 | [diff] [blame] | 1369 | struct page ***pages, size_t maxsize, |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1370 | unsigned maxpages, size_t *_start_offset) |
| 1371 | { |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1372 | unsigned nr, offset, count; |
| 1373 | pgoff_t index; |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1374 | loff_t pos; |
| 1375 | |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1376 | pos = i->xarray_start + i->iov_offset; |
| 1377 | index = pos >> PAGE_SHIFT; |
| 1378 | offset = pos & ~PAGE_MASK; |
| 1379 | *_start_offset = offset; |
| 1380 | |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1381 | count = want_pages_array(pages, maxsize, offset, maxpages); |
| 1382 | if (!count) |
| 1383 | return -ENOMEM; |
Al Viro | 68fe506 | 2022-06-17 13:48:03 -0400 | [diff] [blame] | 1384 | nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1385 | if (nr == 0) |
| 1386 | return 0; |
| 1387 | |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1388 | maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); |
Al Viro | 310d9d5 | 2022-06-11 04:04:33 -0400 | [diff] [blame] | 1389 | i->iov_offset += maxsize; |
| 1390 | i->count -= maxsize; |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1391 | return maxsize; |
David Howells | 7ff506207 | 2020-02-10 10:00:21 +0000 | [diff] [blame] | 1392 | } |
| 1393 | |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1394 | /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ |
Al Viro | dd45ab9 | 2022-06-17 16:07:49 -0400 | [diff] [blame] | 1395 | static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1396 | { |
| 1397 | size_t skip; |
| 1398 | long k; |
| 1399 | |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1400 | if (iter_is_ubuf(i)) |
| 1401 | return (unsigned long)i->ubuf + i->iov_offset; |
| 1402 | |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1403 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1404 | size_t len = i->iov[k].iov_len - skip; |
| 1405 | |
| 1406 | if (unlikely(!len)) |
| 1407 | continue; |
Al Viro | 59dbd7d | 2022-06-21 16:10:37 -0400 | [diff] [blame] | 1408 | if (*size > len) |
| 1409 | *size = len; |
Al Viro | dd45ab9 | 2022-06-17 16:07:49 -0400 | [diff] [blame] | 1410 | return (unsigned long)i->iov[k].iov_base + skip; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1411 | } |
| 1412 | BUG(); // if it had been empty, we wouldn't get called |
| 1413 | } |
| 1414 | |
| 1415 | /* must be done on non-empty ITER_BVEC one */ |
| 1416 | static struct page *first_bvec_segment(const struct iov_iter *i, |
Al Viro | 59dbd7d | 2022-06-21 16:10:37 -0400 | [diff] [blame] | 1417 | size_t *size, size_t *start) |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1418 | { |
| 1419 | struct page *page; |
| 1420 | size_t skip = i->iov_offset, len; |
| 1421 | |
| 1422 | len = i->bvec->bv_len - skip; |
Al Viro | 59dbd7d | 2022-06-21 16:10:37 -0400 | [diff] [blame] | 1423 | if (*size > len) |
| 1424 | *size = len; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1425 | skip += i->bvec->bv_offset; |
| 1426 | page = i->bvec->bv_page + skip / PAGE_SIZE; |
Al Viro | dda8e5d | 2022-06-21 15:55:19 -0400 | [diff] [blame] | 1427 | *start = skip % PAGE_SIZE; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1428 | return page; |
| 1429 | } |
| 1430 | |
Al Viro | 9132955 | 2022-06-10 20:38:20 -0400 | [diff] [blame] | 1431 | static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1432 | struct page ***pages, size_t maxsize, |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1433 | unsigned int maxpages, size_t *start) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1434 | { |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1435 | unsigned int n; |
Al Viro | 1b17f1f | 2014-11-27 14:14:31 -0500 | [diff] [blame] | 1436 | |
| 1437 | if (maxsize > i->count) |
| 1438 | maxsize = i->count; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1439 | if (!maxsize) |
| 1440 | return 0; |
Al Viro | 7392ed1 | 2022-06-11 16:44:21 -0400 | [diff] [blame] | 1441 | if (maxsize > MAX_RW_COUNT) |
| 1442 | maxsize = MAX_RW_COUNT; |
Al Viro | 1b17f1f | 2014-11-27 14:14:31 -0500 | [diff] [blame] | 1443 | |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1444 | if (likely(user_backed_iter(i))) { |
Andreas Gruenbacher | 3337ab0 | 2021-07-12 12:06:14 +0200 | [diff] [blame] | 1445 | unsigned int gup_flags = 0; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1446 | unsigned long addr; |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1447 | int res; |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1448 | |
Andreas Gruenbacher | 3337ab0 | 2021-07-12 12:06:14 +0200 | [diff] [blame] | 1449 | if (iov_iter_rw(i) != WRITE) |
| 1450 | gup_flags |= FOLL_WRITE; |
| 1451 | if (i->nofault) |
| 1452 | gup_flags |= FOLL_NOFAULT; |
| 1453 | |
Al Viro | dd45ab9 | 2022-06-17 16:07:49 -0400 | [diff] [blame] | 1454 | addr = first_iovec_segment(i, &maxsize); |
| 1455 | *start = addr % PAGE_SIZE; |
| 1456 | addr &= PAGE_MASK; |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1457 | n = want_pages_array(pages, maxsize, *start, maxpages); |
| 1458 | if (!n) |
| 1459 | return -ENOMEM; |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1460 | res = get_user_pages_fast(addr, n, gup_flags, *pages); |
Al Viro | 9132955 | 2022-06-10 20:38:20 -0400 | [diff] [blame] | 1461 | if (unlikely(res <= 0)) |
Al Viro | 1b17f1f | 2014-11-27 14:14:31 -0500 | [diff] [blame] | 1462 | return res; |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1463 | maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - *start); |
| 1464 | iov_iter_advance(i, maxsize); |
| 1465 | return maxsize; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1466 | } |
| 1467 | if (iov_iter_is_bvec(i)) { |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1468 | struct page **p; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1469 | struct page *page; |
| 1470 | |
Al Viro | 59dbd7d | 2022-06-21 16:10:37 -0400 | [diff] [blame] | 1471 | page = first_bvec_segment(i, &maxsize, start); |
Al Viro | 3cf42da | 2022-06-17 14:45:41 -0400 | [diff] [blame] | 1472 | n = want_pages_array(pages, maxsize, *start, maxpages); |
| 1473 | if (!n) |
| 1474 | return -ENOMEM; |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1475 | p = *pages; |
Al Viro | dda8e5d | 2022-06-21 15:55:19 -0400 | [diff] [blame] | 1476 | for (int k = 0; k < n; k++) |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1477 | get_page(p[k] = page + k); |
| 1478 | maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); |
Al Viro | 310d9d5 | 2022-06-11 04:04:33 -0400 | [diff] [blame] | 1479 | i->count -= maxsize; |
| 1480 | i->iov_offset += maxsize; |
| 1481 | if (i->iov_offset == i->bvec->bv_len) { |
| 1482 | i->iov_offset = 0; |
| 1483 | i->bvec++; |
| 1484 | i->nr_segs--; |
| 1485 | } |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1486 | return maxsize; |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1487 | } |
| 1488 | if (iov_iter_is_pipe(i)) |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1489 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1490 | if (iov_iter_is_xarray(i)) |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1491 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); |
Al Viro | 3d671ca | 2021-04-25 09:14:44 -0400 | [diff] [blame] | 1492 | return -EFAULT; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1493 | } |
Al Viro | 9132955 | 2022-06-10 20:38:20 -0400 | [diff] [blame] | 1494 | |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1495 | ssize_t iov_iter_get_pages2(struct iov_iter *i, |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1496 | struct page **pages, size_t maxsize, unsigned maxpages, |
| 1497 | size_t *start) |
| 1498 | { |
| 1499 | if (!maxpages) |
| 1500 | return 0; |
| 1501 | BUG_ON(!pages); |
| 1502 | |
| 1503 | return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); |
| 1504 | } |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1505 | EXPORT_SYMBOL(iov_iter_get_pages2); |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1506 | |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1507 | ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, |
Al Viro | 9132955 | 2022-06-10 20:38:20 -0400 | [diff] [blame] | 1508 | struct page ***pages, size_t maxsize, |
| 1509 | size_t *start) |
| 1510 | { |
| 1511 | ssize_t len; |
| 1512 | |
| 1513 | *pages = NULL; |
| 1514 | |
Al Viro | 451c0ba | 2022-06-17 13:54:15 -0400 | [diff] [blame] | 1515 | len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); |
Al Viro | 9132955 | 2022-06-10 20:38:20 -0400 | [diff] [blame] | 1516 | if (len <= 0) { |
| 1517 | kvfree(*pages); |
| 1518 | *pages = NULL; |
| 1519 | } |
| 1520 | return len; |
| 1521 | } |
Al Viro | eba2d3d | 2022-06-10 13:05:12 -0400 | [diff] [blame] | 1522 | EXPORT_SYMBOL(iov_iter_get_pages_alloc2); |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1523 | |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1524 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
| 1525 | struct iov_iter *i) |
| 1526 | { |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1527 | __wsum sum, next; |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1528 | sum = *csum; |
David Howells | 9ea9ce0 | 2018-10-20 00:57:56 +0100 | [diff] [blame] | 1529 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1530 | WARN_ON(1); |
| 1531 | return 0; |
| 1532 | } |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1533 | iterate_and_advance(i, bytes, base, len, off, ({ |
| 1534 | next = csum_and_copy_from_user(base, addr + off, len); |
Al Viro | 2495bdcc | 2021-04-30 13:40:48 -0400 | [diff] [blame] | 1535 | sum = csum_block_add(sum, next, off); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1536 | next ? 0 : len; |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1537 | }), ({ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1538 | sum = csum_and_memcpy(addr + off, base, len, sum, off); |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1539 | }) |
| 1540 | ) |
| 1541 | *csum = sum; |
| 1542 | return bytes; |
| 1543 | } |
| 1544 | EXPORT_SYMBOL(csum_and_copy_from_iter); |
| 1545 | |
Willem de Bruijn | 52cbd23 | 2021-02-03 14:29:52 -0500 | [diff] [blame] | 1546 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1547 | struct iov_iter *i) |
| 1548 | { |
Willem de Bruijn | 52cbd23 | 2021-02-03 14:29:52 -0500 | [diff] [blame] | 1549 | struct csum_state *csstate = _csstate; |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1550 | __wsum sum, next; |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 1551 | |
Al Viro | 78e1f38 | 2018-11-25 16:24:16 -0500 | [diff] [blame] | 1552 | if (unlikely(iov_iter_is_discard(i))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1553 | WARN_ON(1); /* for now */ |
| 1554 | return 0; |
| 1555 | } |
Al Viro | 6852df1 | 2021-05-02 17:24:40 -0400 | [diff] [blame] | 1556 | |
| 1557 | sum = csum_shift(csstate->csum, csstate->off); |
| 1558 | if (unlikely(iov_iter_is_pipe(i))) |
| 1559 | bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); |
| 1560 | else iterate_and_advance(i, bytes, base, len, off, ({ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1561 | next = csum_and_copy_to_user(addr + off, base, len); |
Al Viro | 2495bdcc | 2021-04-30 13:40:48 -0400 | [diff] [blame] | 1562 | sum = csum_block_add(sum, next, off); |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1563 | next ? 0 : len; |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1564 | }), ({ |
Al Viro | 7baa509 | 2021-05-02 11:35:03 -0400 | [diff] [blame] | 1565 | sum = csum_and_memcpy(base, addr + off, len, sum, off); |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1566 | }) |
| 1567 | ) |
Al Viro | 594e450 | 2021-06-05 10:19:30 -0400 | [diff] [blame] | 1568 | csstate->csum = csum_shift(sum, csstate->off); |
| 1569 | csstate->off += bytes; |
Al Viro | a604ec7 | 2014-11-24 01:08:00 -0500 | [diff] [blame] | 1570 | return bytes; |
| 1571 | } |
| 1572 | EXPORT_SYMBOL(csum_and_copy_to_iter); |
| 1573 | |
Sagi Grimberg | d05f443 | 2018-12-03 17:52:09 -0800 | [diff] [blame] | 1574 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
| 1575 | struct iov_iter *i) |
| 1576 | { |
Herbert Xu | 7999096 | 2020-06-12 16:57:37 +1000 | [diff] [blame] | 1577 | #ifdef CONFIG_CRYPTO_HASH |
Sagi Grimberg | d05f443 | 2018-12-03 17:52:09 -0800 | [diff] [blame] | 1578 | struct ahash_request *hash = hashp; |
| 1579 | struct scatterlist sg; |
| 1580 | size_t copied; |
| 1581 | |
| 1582 | copied = copy_to_iter(addr, bytes, i); |
| 1583 | sg_init_one(&sg, addr, copied); |
| 1584 | ahash_request_set_crypt(hash, &sg, NULL, copied); |
| 1585 | crypto_ahash_update(hash); |
| 1586 | return copied; |
YueHaibing | 27fad74 | 2019-04-04 10:31:14 +0800 | [diff] [blame] | 1587 | #else |
| 1588 | return 0; |
| 1589 | #endif |
Sagi Grimberg | d05f443 | 2018-12-03 17:52:09 -0800 | [diff] [blame] | 1590 | } |
| 1591 | EXPORT_SYMBOL(hash_and_copy_to_iter); |
| 1592 | |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1593 | static int iov_npages(const struct iov_iter *i, int maxpages) |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1594 | { |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1595 | size_t skip = i->iov_offset, size = i->count; |
| 1596 | const struct iovec *p; |
Al Viro | e0f2dc4 | 2014-11-27 14:09:46 -0500 | [diff] [blame] | 1597 | int npages = 0; |
| 1598 | |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1599 | for (p = i->iov; size; skip = 0, p++) { |
| 1600 | unsigned offs = offset_in_page(p->iov_base + skip); |
| 1601 | size_t len = min(p->iov_len - skip, size); |
Al Viro | e0f2dc4 | 2014-11-27 14:09:46 -0500 | [diff] [blame] | 1602 | |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1603 | if (len) { |
| 1604 | size -= len; |
| 1605 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); |
| 1606 | if (unlikely(npages > maxpages)) |
| 1607 | return maxpages; |
| 1608 | } |
| 1609 | } |
| 1610 | return npages; |
| 1611 | } |
| 1612 | |
| 1613 | static int bvec_npages(const struct iov_iter *i, int maxpages) |
| 1614 | { |
| 1615 | size_t skip = i->iov_offset, size = i->count; |
| 1616 | const struct bio_vec *p; |
| 1617 | int npages = 0; |
| 1618 | |
| 1619 | for (p = i->bvec; size; skip = 0, p++) { |
| 1620 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; |
| 1621 | size_t len = min(p->bv_len - skip, size); |
| 1622 | |
| 1623 | size -= len; |
| 1624 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); |
| 1625 | if (unlikely(npages > maxpages)) |
| 1626 | return maxpages; |
| 1627 | } |
| 1628 | return npages; |
| 1629 | } |
| 1630 | |
| 1631 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
| 1632 | { |
| 1633 | if (unlikely(!i->count)) |
| 1634 | return 0; |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1635 | if (likely(iter_is_ubuf(i))) { |
| 1636 | unsigned offs = offset_in_page(i->ubuf + i->iov_offset); |
| 1637 | int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); |
| 1638 | return min(npages, maxpages); |
| 1639 | } |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1640 | /* iovec and kvec have identical layouts */ |
| 1641 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
| 1642 | return iov_npages(i, maxpages); |
| 1643 | if (iov_iter_is_bvec(i)) |
| 1644 | return bvec_npages(i, maxpages); |
| 1645 | if (iov_iter_is_pipe(i)) { |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1646 | int npages; |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1647 | |
| 1648 | if (!sanity(i)) |
| 1649 | return 0; |
| 1650 | |
Al Viro | 12d426a | 2022-06-15 09:44:38 -0400 | [diff] [blame] | 1651 | pipe_npages(i, &npages); |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1652 | return min(npages, maxpages); |
| 1653 | } |
| 1654 | if (iov_iter_is_xarray(i)) { |
Al Viro | e4f8df8 | 2021-05-03 11:05:29 -0400 | [diff] [blame] | 1655 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
| 1656 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); |
Al Viro | 66531c6 | 2021-04-25 16:00:48 -0400 | [diff] [blame] | 1657 | return min(npages, maxpages); |
| 1658 | } |
| 1659 | return 0; |
Al Viro | 62a8067 | 2014-04-04 23:12:29 -0400 | [diff] [blame] | 1660 | } |
Al Viro | f67da30 | 2014-03-19 01:16:16 -0400 | [diff] [blame] | 1661 | EXPORT_SYMBOL(iov_iter_npages); |
Al Viro | 4b8164b | 2015-01-31 20:08:47 -0500 | [diff] [blame] | 1662 | |
| 1663 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) |
| 1664 | { |
| 1665 | *new = *old; |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 1666 | if (unlikely(iov_iter_is_pipe(new))) { |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 1667 | WARN_ON(1); |
| 1668 | return NULL; |
| 1669 | } |
David Howells | 00e2370 | 2018-10-22 13:07:28 +0100 | [diff] [blame] | 1670 | if (iov_iter_is_bvec(new)) |
Al Viro | 4b8164b | 2015-01-31 20:08:47 -0500 | [diff] [blame] | 1671 | return new->bvec = kmemdup(new->bvec, |
| 1672 | new->nr_segs * sizeof(struct bio_vec), |
| 1673 | flags); |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1674 | else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) |
Al Viro | 4b8164b | 2015-01-31 20:08:47 -0500 | [diff] [blame] | 1675 | /* iovec and kvec have identical layout */ |
| 1676 | return new->iov = kmemdup(new->iov, |
| 1677 | new->nr_segs * sizeof(struct iovec), |
| 1678 | flags); |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1679 | return NULL; |
Al Viro | 4b8164b | 2015-01-31 20:08:47 -0500 | [diff] [blame] | 1680 | } |
| 1681 | EXPORT_SYMBOL(dup_iter); |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1682 | |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1683 | static int copy_compat_iovec_from_user(struct iovec *iov, |
| 1684 | const struct iovec __user *uvec, unsigned long nr_segs) |
| 1685 | { |
| 1686 | const struct compat_iovec __user *uiov = |
| 1687 | (const struct compat_iovec __user *)uvec; |
| 1688 | int ret = -EFAULT, i; |
| 1689 | |
Christoph Hellwig | a959a97 | 2021-01-11 18:19:26 +0100 | [diff] [blame] | 1690 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1691 | return -EFAULT; |
| 1692 | |
| 1693 | for (i = 0; i < nr_segs; i++) { |
| 1694 | compat_uptr_t buf; |
| 1695 | compat_ssize_t len; |
| 1696 | |
| 1697 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); |
| 1698 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); |
| 1699 | |
| 1700 | /* check for compat_size_t not fitting in compat_ssize_t .. */ |
| 1701 | if (len < 0) { |
| 1702 | ret = -EINVAL; |
| 1703 | goto uaccess_end; |
| 1704 | } |
| 1705 | iov[i].iov_base = compat_ptr(buf); |
| 1706 | iov[i].iov_len = len; |
| 1707 | } |
| 1708 | |
| 1709 | ret = 0; |
| 1710 | uaccess_end: |
| 1711 | user_access_end(); |
| 1712 | return ret; |
| 1713 | } |
| 1714 | |
| 1715 | static int copy_iovec_from_user(struct iovec *iov, |
| 1716 | const struct iovec __user *uvec, unsigned long nr_segs) |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1717 | { |
| 1718 | unsigned long seg; |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1719 | |
| 1720 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
| 1721 | return -EFAULT; |
| 1722 | for (seg = 0; seg < nr_segs; seg++) { |
| 1723 | if ((ssize_t)iov[seg].iov_len < 0) |
| 1724 | return -EINVAL; |
| 1725 | } |
| 1726 | |
| 1727 | return 0; |
| 1728 | } |
| 1729 | |
| 1730 | struct iovec *iovec_from_user(const struct iovec __user *uvec, |
| 1731 | unsigned long nr_segs, unsigned long fast_segs, |
| 1732 | struct iovec *fast_iov, bool compat) |
| 1733 | { |
| 1734 | struct iovec *iov = fast_iov; |
| 1735 | int ret; |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1736 | |
| 1737 | /* |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1738 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
| 1739 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1740 | * traditionally returned zero for zero segments, so... |
| 1741 | */ |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1742 | if (nr_segs == 0) |
| 1743 | return iov; |
| 1744 | if (nr_segs > UIO_MAXIOV) |
| 1745 | return ERR_PTR(-EINVAL); |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1746 | if (nr_segs > fast_segs) { |
| 1747 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1748 | if (!iov) |
| 1749 | return ERR_PTR(-ENOMEM); |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1750 | } |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1751 | |
| 1752 | if (compat) |
| 1753 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); |
| 1754 | else |
| 1755 | ret = copy_iovec_from_user(iov, uvec, nr_segs); |
| 1756 | if (ret) { |
| 1757 | if (iov != fast_iov) |
| 1758 | kfree(iov); |
| 1759 | return ERR_PTR(ret); |
| 1760 | } |
| 1761 | |
| 1762 | return iov; |
| 1763 | } |
| 1764 | |
| 1765 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, |
| 1766 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, |
| 1767 | struct iov_iter *i, bool compat) |
| 1768 | { |
| 1769 | ssize_t total_len = 0; |
| 1770 | unsigned long seg; |
| 1771 | struct iovec *iov; |
| 1772 | |
| 1773 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); |
| 1774 | if (IS_ERR(iov)) { |
| 1775 | *iovp = NULL; |
| 1776 | return PTR_ERR(iov); |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1777 | } |
| 1778 | |
| 1779 | /* |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1780 | * According to the Single Unix Specification we should return EINVAL if |
| 1781 | * an element length is < 0 when cast to ssize_t or if the total length |
| 1782 | * would overflow the ssize_t return value of the system call. |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1783 | * |
| 1784 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the |
| 1785 | * overflow case. |
| 1786 | */ |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1787 | for (seg = 0; seg < nr_segs; seg++) { |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1788 | ssize_t len = (ssize_t)iov[seg].iov_len; |
| 1789 | |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1790 | if (!access_ok(iov[seg].iov_base, len)) { |
| 1791 | if (iov != *iovp) |
| 1792 | kfree(iov); |
| 1793 | *iovp = NULL; |
| 1794 | return -EFAULT; |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1795 | } |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1796 | |
| 1797 | if (len > MAX_RW_COUNT - total_len) { |
| 1798 | len = MAX_RW_COUNT - total_len; |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1799 | iov[seg].iov_len = len; |
| 1800 | } |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1801 | total_len += len; |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1802 | } |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1803 | |
| 1804 | iov_iter_init(i, type, iov, nr_segs, total_len); |
| 1805 | if (iov == *iovp) |
| 1806 | *iovp = NULL; |
| 1807 | else |
| 1808 | *iovp = iov; |
| 1809 | return total_len; |
David Laight | fb041b5 | 2020-09-25 06:51:39 +0200 | [diff] [blame] | 1810 | } |
| 1811 | |
Vegard Nossum | ffecee4 | 2016-10-08 11:18:07 +0200 | [diff] [blame] | 1812 | /** |
| 1813 | * import_iovec() - Copy an array of &struct iovec from userspace |
| 1814 | * into the kernel, check that it is valid, and initialize a new |
| 1815 | * &struct iov_iter iterator to access it. |
| 1816 | * |
| 1817 | * @type: One of %READ or %WRITE. |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1818 | * @uvec: Pointer to the userspace array. |
Vegard Nossum | ffecee4 | 2016-10-08 11:18:07 +0200 | [diff] [blame] | 1819 | * @nr_segs: Number of elements in userspace array. |
| 1820 | * @fast_segs: Number of elements in @iov. |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1821 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
Vegard Nossum | ffecee4 | 2016-10-08 11:18:07 +0200 | [diff] [blame] | 1822 | * on-stack) kernel array. |
| 1823 | * @i: Pointer to iterator that will be initialized on success. |
| 1824 | * |
| 1825 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, |
| 1826 | * then this function places %NULL in *@iov on return. Otherwise, a new |
| 1827 | * array will be allocated and the result placed in *@iov. This means that |
| 1828 | * the caller may call kfree() on *@iov regardless of whether the small |
| 1829 | * on-stack array was used or not (and regardless of whether this function |
| 1830 | * returns an error or not). |
| 1831 | * |
Jens Axboe | 87e5e6d | 2019-05-14 16:02:22 -0600 | [diff] [blame] | 1832 | * Return: Negative error code on error, bytes imported on success |
Vegard Nossum | ffecee4 | 2016-10-08 11:18:07 +0200 | [diff] [blame] | 1833 | */ |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1834 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1835 | unsigned nr_segs, unsigned fast_segs, |
Christoph Hellwig | bfdc597 | 2020-09-25 06:51:40 +0200 | [diff] [blame] | 1836 | struct iovec **iovp, struct iov_iter *i) |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1837 | { |
Christoph Hellwig | 89cd35c | 2020-09-25 06:51:41 +0200 | [diff] [blame] | 1838 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
| 1839 | in_compat_syscall()); |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1840 | } |
| 1841 | EXPORT_SYMBOL(import_iovec); |
| 1842 | |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1843 | int import_single_range(int rw, void __user *buf, size_t len, |
| 1844 | struct iovec *iov, struct iov_iter *i) |
| 1845 | { |
| 1846 | if (len > MAX_RW_COUNT) |
| 1847 | len = MAX_RW_COUNT; |
Linus Torvalds | 96d4f26 | 2019-01-03 18:57:57 -0800 | [diff] [blame] | 1848 | if (unlikely(!access_ok(buf, len))) |
Al Viro | bc917be | 2015-03-21 17:45:43 -0400 | [diff] [blame] | 1849 | return -EFAULT; |
| 1850 | |
| 1851 | iov->iov_base = buf; |
| 1852 | iov->iov_len = len; |
| 1853 | iov_iter_init(i, rw, iov, 1, len); |
| 1854 | return 0; |
| 1855 | } |
Al Viro | e126758 | 2015-12-06 20:38:56 -0500 | [diff] [blame] | 1856 | EXPORT_SYMBOL(import_single_range); |
Jens Axboe | 8fb0f47 | 2021-09-10 11:18:36 -0600 | [diff] [blame] | 1857 | |
| 1858 | /** |
| 1859 | * iov_iter_restore() - Restore a &struct iov_iter to the same state as when |
| 1860 | * iov_iter_save_state() was called. |
| 1861 | * |
| 1862 | * @i: &struct iov_iter to restore |
| 1863 | * @state: state to restore from |
| 1864 | * |
| 1865 | * Used after iov_iter_save_state() to bring restore @i, if operations may |
| 1866 | * have advanced it. |
| 1867 | * |
| 1868 | * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC |
| 1869 | */ |
| 1870 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) |
| 1871 | { |
| 1872 | if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1873 | !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) |
Jens Axboe | 8fb0f47 | 2021-09-10 11:18:36 -0600 | [diff] [blame] | 1874 | return; |
| 1875 | i->iov_offset = state->iov_offset; |
| 1876 | i->count = state->count; |
Al Viro | fcb14cb | 2022-05-22 14:59:25 -0400 | [diff] [blame] | 1877 | if (iter_is_ubuf(i)) |
| 1878 | return; |
Jens Axboe | 8fb0f47 | 2021-09-10 11:18:36 -0600 | [diff] [blame] | 1879 | /* |
| 1880 | * For the *vec iters, nr_segs + iov is constant - if we increment |
| 1881 | * the vec, then we also decrement the nr_segs count. Hence we don't |
| 1882 | * need to track both of these, just one is enough and we can deduct |
| 1883 | * the other from that. ITER_KVEC and ITER_IOVEC are the same struct |
| 1884 | * size, so we can just increment the iov pointer as they are unionzed. |
| 1885 | * ITER_BVEC _may_ be the same size on some archs, but on others it is |
| 1886 | * not. Be safe and handle it separately. |
| 1887 | */ |
| 1888 | BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); |
| 1889 | if (iov_iter_is_bvec(i)) |
| 1890 | i->bvec -= state->nr_segs - i->nr_segs; |
| 1891 | else |
| 1892 | i->iov -= state->nr_segs - i->nr_segs; |
| 1893 | i->nr_segs = state->nr_segs; |
| 1894 | } |