Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7999096f | 2 | #include <crypto/hash.h> |
4f18cd31 | 3 | #include <linux/export.h> |
2f8b5444 | 4 | #include <linux/bvec.h> |
4d0e9df5 | 5 | #include <linux/fault-inject-usercopy.h> |
4f18cd31 AV |
6 | #include <linux/uio.h> |
7 | #include <linux/pagemap.h> | |
28961998 | 8 | #include <linux/highmem.h> |
91f79c43 AV |
9 | #include <linux/slab.h> |
10 | #include <linux/vmalloc.h> | |
241699cd | 11 | #include <linux/splice.h> |
bfdc5970 | 12 | #include <linux/compat.h> |
a604ec7e | 13 | #include <net/checksum.h> |
d05f4435 | 14 | #include <linux/scatterlist.h> |
d0ef4c36 | 15 | #include <linux/instrumented.h> |
4f18cd31 | 16 | |
241699cd AV |
17 | #define PIPE_PARANOIA /* for now */ |
18 | ||
fcb14cb1 AV |
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 | ||
5c67aa90 | 29 | /* covers iovec and kvec alike */ |
a6e4ec7b | 30 | #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ |
7baa5099 | 31 | size_t off = 0; \ |
a6e4ec7b | 32 | size_t skip = i->iov_offset; \ |
7a1bcb5d | 33 | do { \ |
7baa5099 AV |
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; \ | |
7a1bcb5d AV |
41 | if (skip < __p->iov_len) \ |
42 | break; \ | |
43 | } \ | |
44 | __p++; \ | |
45 | skip = 0; \ | |
46 | } while (n); \ | |
a6e4ec7b | 47 | i->iov_offset = skip; \ |
7baa5099 | 48 | n = off; \ |
04a31165 AV |
49 | } |
50 | ||
a6e4ec7b | 51 | #define iterate_bvec(i, n, base, len, off, p, STEP) { \ |
7baa5099 | 52 | size_t off = 0; \ |
a6e4ec7b | 53 | unsigned skip = i->iov_offset; \ |
7491a2bf AV |
54 | while (n) { \ |
55 | unsigned offset = p->bv_offset + skip; \ | |
1b4fb5ff | 56 | unsigned left; \ |
21b56c84 AV |
57 | void *kaddr = kmap_local_page(p->bv_page + \ |
58 | offset / PAGE_SIZE); \ | |
7baa5099 | 59 | base = kaddr + offset % PAGE_SIZE; \ |
a6e4ec7b | 60 | len = min(min(n, (size_t)(p->bv_len - skip)), \ |
7491a2bf | 61 | (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ |
1b4fb5ff | 62 | left = (STEP); \ |
21b56c84 | 63 | kunmap_local(kaddr); \ |
7baa5099 AV |
64 | len -= left; \ |
65 | off += len; \ | |
66 | skip += len; \ | |
7491a2bf AV |
67 | if (skip == p->bv_len) { \ |
68 | skip = 0; \ | |
69 | p++; \ | |
70 | } \ | |
7baa5099 | 71 | n -= len; \ |
1b4fb5ff AV |
72 | if (left) \ |
73 | break; \ | |
7491a2bf | 74 | } \ |
a6e4ec7b | 75 | i->iov_offset = skip; \ |
7baa5099 | 76 | n = off; \ |
04a31165 AV |
77 | } |
78 | ||
a6e4ec7b | 79 | #define iterate_xarray(i, n, base, len, __off, STEP) { \ |
1b4fb5ff | 80 | __label__ __out; \ |
622838f3 | 81 | size_t __off = 0; \ |
821979f5 | 82 | struct folio *folio; \ |
a6e4ec7b | 83 | loff_t start = i->xarray_start + i->iov_offset; \ |
4b179e9a | 84 | pgoff_t index = start / PAGE_SIZE; \ |
7ff50620 DH |
85 | XA_STATE(xas, i->xarray, index); \ |
86 | \ | |
821979f5 | 87 | len = PAGE_SIZE - offset_in_page(start); \ |
7baa5099 | 88 | rcu_read_lock(); \ |
821979f5 | 89 | xas_for_each(&xas, folio, ULONG_MAX) { \ |
7baa5099 | 90 | unsigned left; \ |
821979f5 MWO |
91 | size_t offset; \ |
92 | if (xas_retry(&xas, folio)) \ | |
7baa5099 | 93 | continue; \ |
821979f5 | 94 | if (WARN_ON(xa_is_value(folio))) \ |
7baa5099 | 95 | break; \ |
821979f5 | 96 | if (WARN_ON(folio_test_hugetlb(folio))) \ |
7baa5099 | 97 | break; \ |
821979f5 MWO |
98 | offset = offset_in_folio(folio, start + __off); \ |
99 | while (offset < folio_size(folio)) { \ | |
100 | base = kmap_local_folio(folio, offset); \ | |
7baa5099 AV |
101 | len = min(n, len); \ |
102 | left = (STEP); \ | |
821979f5 | 103 | kunmap_local(base); \ |
7baa5099 AV |
104 | len -= left; \ |
105 | __off += len; \ | |
106 | n -= len; \ | |
107 | if (left || n == 0) \ | |
108 | goto __out; \ | |
821979f5 MWO |
109 | offset += len; \ |
110 | len = PAGE_SIZE; \ | |
7baa5099 | 111 | } \ |
7ff50620 | 112 | } \ |
1b4fb5ff | 113 | __out: \ |
7ff50620 | 114 | rcu_read_unlock(); \ |
821979f5 | 115 | i->iov_offset += __off; \ |
622838f3 | 116 | n = __off; \ |
7ff50620 DH |
117 | } |
118 | ||
7baa5099 | 119 | #define __iterate_and_advance(i, n, base, len, off, I, K) { \ |
dd254f5a AV |
120 | if (unlikely(i->count < n)) \ |
121 | n = i->count; \ | |
f5da8354 | 122 | if (likely(n)) { \ |
fcb14cb1 AV |
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))) { \ | |
5c67aa90 | 129 | const struct iovec *iov = i->iov; \ |
7baa5099 AV |
130 | void __user *base; \ |
131 | size_t len; \ | |
132 | iterate_iovec(i, n, base, len, off, \ | |
a6e4ec7b | 133 | iov, (I)) \ |
28f38db7 AV |
134 | i->nr_segs -= iov - i->iov; \ |
135 | i->iov = iov; \ | |
136 | } else if (iov_iter_is_bvec(i)) { \ | |
1bdc76ae | 137 | const struct bio_vec *bvec = i->bvec; \ |
7baa5099 AV |
138 | void *base; \ |
139 | size_t len; \ | |
140 | iterate_bvec(i, n, base, len, off, \ | |
a6e4ec7b | 141 | bvec, (K)) \ |
7491a2bf AV |
142 | i->nr_segs -= bvec - i->bvec; \ |
143 | i->bvec = bvec; \ | |
28f38db7 | 144 | } else if (iov_iter_is_kvec(i)) { \ |
5c67aa90 | 145 | const struct kvec *kvec = i->kvec; \ |
7baa5099 AV |
146 | void *base; \ |
147 | size_t len; \ | |
148 | iterate_iovec(i, n, base, len, off, \ | |
a6e4ec7b | 149 | kvec, (K)) \ |
dd254f5a AV |
150 | i->nr_segs -= kvec - i->kvec; \ |
151 | i->kvec = kvec; \ | |
28f38db7 | 152 | } else if (iov_iter_is_xarray(i)) { \ |
7baa5099 AV |
153 | void *base; \ |
154 | size_t len; \ | |
155 | iterate_xarray(i, n, base, len, off, \ | |
a6e4ec7b | 156 | (K)) \ |
7ce2a91e | 157 | } \ |
dd254f5a | 158 | i->count -= n; \ |
7ce2a91e | 159 | } \ |
7ce2a91e | 160 | } |
7baa5099 AV |
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)) | |
7ce2a91e | 163 | |
09fc68dc AV |
164 | static int copyout(void __user *to, const void *from, size_t n) |
165 | { | |
4d0e9df5 AL |
166 | if (should_fail_usercopy()) |
167 | return n; | |
96d4f267 | 168 | if (access_ok(to, n)) { |
d0ef4c36 | 169 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
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 | { | |
33b75c1d AP |
177 | size_t res = n; |
178 | ||
4d0e9df5 AL |
179 | if (should_fail_usercopy()) |
180 | return n; | |
96d4f267 | 181 | if (access_ok(from, n)) { |
33b75c1d AP |
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); | |
09fc68dc | 185 | } |
33b75c1d | 186 | return res; |
09fc68dc AV |
187 | } |
188 | ||
2dcedb2a AV |
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 | ||
241699cd AV |
195 | #ifdef PIPE_PARANOIA |
196 | static bool sanity(const struct iov_iter *i) | |
197 | { | |
198 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
199 | unsigned int p_head = pipe->head; |
200 | unsigned int p_tail = pipe->tail; | |
8cefc107 DH |
201 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); |
202 | unsigned int i_head = i->head; | |
203 | unsigned int idx; | |
204 | ||
10f525a8 | 205 | if (i->last_offset) { |
241699cd | 206 | struct pipe_buffer *p; |
8cefc107 | 207 | if (unlikely(p_occupancy == 0)) |
241699cd | 208 | goto Bad; // pipe must be non-empty |
8cefc107 | 209 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
210 | goto Bad; // must be at the last buffer... |
211 | ||
2dcedb2a | 212 | p = pipe_buf(pipe, i_head); |
10f525a8 | 213 | if (unlikely(p->offset + p->len != abs(i->last_offset))) |
241699cd AV |
214 | goto Bad; // ... at the end of segment |
215 | } else { | |
8cefc107 | 216 | if (i_head != p_head) |
241699cd AV |
217 | goto Bad; // must be right after the last buffer |
218 | } | |
219 | return true; | |
220 | Bad: | |
10f525a8 | 221 | printk(KERN_ERR "idx = %d, offset = %d\n", i_head, i->last_offset); |
8cefc107 DH |
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++) | |
241699cd AV |
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 | ||
47b7fcae AV |
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 | ||
10f525a8 | 265 | static inline int last_offset(const struct pipe_buffer *buf) |
8fad7767 | 266 | { |
10f525a8 AV |
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); | |
8fad7767 AV |
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; | |
10f525a8 | 277 | int offset = i->last_offset; |
8fad7767 AV |
278 | struct pipe_buffer *buf; |
279 | struct page *page; | |
280 | ||
10f525a8 AV |
281 | if (offset > 0 && offset < PAGE_SIZE) { |
282 | // some space in the last buffer; add to it | |
8fad7767 | 283 | buf = pipe_buf(pipe, pipe->head - 1); |
10f525a8 AV |
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; | |
8fad7767 AV |
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; | |
10f525a8 | 300 | i->last_offset = size; |
8fad7767 AV |
301 | i->count -= size; |
302 | return page; | |
303 | } | |
304 | ||
241699cd AV |
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; | |
47b7fcae | 309 | unsigned int head = pipe->head; |
241699cd AV |
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 | ||
10f525a8 | 320 | if (offset && i->last_offset == -offset) { // could we merge it? |
47b7fcae AV |
321 | struct pipe_buffer *buf = pipe_buf(pipe, head - 1); |
322 | if (buf->page == page) { | |
241699cd | 323 | buf->len += bytes; |
10f525a8 | 324 | i->last_offset -= bytes; |
47b7fcae AV |
325 | i->count -= bytes; |
326 | return bytes; | |
241699cd | 327 | } |
241699cd | 328 | } |
47b7fcae | 329 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
241699cd | 330 | return 0; |
8cefc107 | 331 | |
47b7fcae | 332 | push_page(pipe, page, offset, bytes); |
10f525a8 | 333 | i->last_offset = -(offset + bytes); |
47b7fcae | 334 | i->head = head; |
241699cd AV |
335 | i->count -= bytes; |
336 | return bytes; | |
337 | } | |
338 | ||
171a0203 | 339 | /* |
a6294593 AG |
340 | * fault_in_iov_iter_readable - fault in iov iterator for reading |
341 | * @i: iterator | |
342 | * @size: maximum length | |
343 | * | |
171a0203 | 344 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
a6294593 AG |
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()). | |
171a0203 | 349 | * |
a6294593 | 350 | * Always returns 0 for non-userspace iterators. |
171a0203 | 351 | */ |
a6294593 | 352 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) |
171a0203 | 353 | { |
fcb14cb1 AV |
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)) { | |
a6294593 | 359 | size_t count = min(size, iov_iter_count(i)); |
8409a0d2 AV |
360 | const struct iovec *p; |
361 | size_t skip; | |
362 | ||
a6294593 AG |
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; | |
8409a0d2 AV |
367 | |
368 | if (unlikely(!len)) | |
369 | continue; | |
a6294593 AG |
370 | ret = fault_in_readable(p->iov_base + skip, len); |
371 | count -= len - ret; | |
372 | if (ret) | |
373 | break; | |
8409a0d2 | 374 | } |
a6294593 | 375 | return count + size; |
171a0203 AA |
376 | } |
377 | return 0; | |
378 | } | |
a6294593 | 379 | EXPORT_SYMBOL(fault_in_iov_iter_readable); |
171a0203 | 380 | |
cdd591fc AG |
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 | { | |
fcb14cb1 AV |
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)) { | |
cdd591fc AG |
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 | ||
aa563d7b | 424 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
425 | const struct iovec *iov, unsigned long nr_segs, |
426 | size_t count) | |
427 | { | |
aa563d7b | 428 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
429 | *i = (struct iov_iter) { |
430 | .iter_type = ITER_IOVEC, | |
3337ab08 | 431 | .nofault = false, |
fcb14cb1 | 432 | .user_backed = true, |
8cd54c1c AV |
433 | .data_source = direction, |
434 | .iov = iov, | |
435 | .nr_segs = nr_segs, | |
436 | .iov_offset = 0, | |
437 | .count = count | |
438 | }; | |
71d8e532 AV |
439 | } |
440 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 441 | |
12d426ab AV |
442 | // returns the offset in partial buffer (if any) |
443 | static inline unsigned int pipe_npages(const struct iov_iter *i, int *npages) | |
241699cd | 444 | { |
12d426ab AV |
445 | struct pipe_inode_info *pipe = i->pipe; |
446 | int used = pipe->head - pipe->tail; | |
10f525a8 | 447 | int off = i->last_offset; |
8cefc107 | 448 | |
12d426ab AV |
449 | *npages = max((int)pipe->max_usage - used, 0); |
450 | ||
10f525a8 | 451 | if (off > 0 && off < PAGE_SIZE) { // anon and not full |
12d426ab AV |
452 | (*npages)++; |
453 | return off; | |
241699cd | 454 | } |
12d426ab | 455 | return 0; |
241699cd AV |
456 | } |
457 | ||
241699cd AV |
458 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
459 | struct iov_iter *i) | |
460 | { | |
8fad7767 | 461 | unsigned int off, chunk; |
241699cd | 462 | |
8fad7767 AV |
463 | if (unlikely(bytes > i->count)) |
464 | bytes = i->count; | |
465 | if (unlikely(!bytes)) | |
241699cd AV |
466 | return 0; |
467 | ||
8fad7767 | 468 | if (!sanity(i)) |
241699cd | 469 | return 0; |
8fad7767 AV |
470 | |
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); | |
241699cd | 477 | addr += chunk; |
8fad7767 | 478 | } |
241699cd AV |
479 | return bytes; |
480 | } | |
481 | ||
f9152895 AV |
482 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
483 | __wsum sum, size_t off) | |
484 | { | |
cc44c17b | 485 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
486 | return csum_block_add(sum, next, off); |
487 | } | |
488 | ||
78e1f386 | 489 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
6852df12 | 490 | struct iov_iter *i, __wsum *sump) |
78e1f386 | 491 | { |
6852df12 AV |
492 | __wsum sum = *sump; |
493 | size_t off = 0; | |
8fad7767 AV |
494 | unsigned int chunk, r; |
495 | ||
496 | if (unlikely(bytes > i->count)) | |
497 | bytes = i->count; | |
498 | if (unlikely(!bytes)) | |
499 | return 0; | |
78e1f386 AV |
500 | |
501 | if (!sanity(i)) | |
502 | return 0; | |
503 | ||
6852df12 | 504 | while (bytes) { |
8fad7767 AV |
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); | |
6852df12 | 512 | sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); |
2495bdcc | 513 | kunmap_local(p); |
78e1f386 | 514 | off += chunk; |
8fad7767 | 515 | bytes -= chunk; |
6852df12 AV |
516 | } |
517 | *sump = sum; | |
6852df12 | 518 | return off; |
78e1f386 AV |
519 | } |
520 | ||
aa28de27 | 521 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 522 | { |
00e23707 | 523 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 524 | return copy_pipe_to_iter(addr, bytes, i); |
fcb14cb1 | 525 | if (user_backed_iter(i)) |
09fc68dc | 526 | might_fault(); |
7baa5099 AV |
527 | iterate_and_advance(i, bytes, base, len, off, |
528 | copyout(base, addr + off, len), | |
529 | memcpy(base, addr + off, len) | |
3d4d3e48 | 530 | ) |
62a8067a | 531 | |
3d4d3e48 | 532 | return bytes; |
c35e0248 | 533 | } |
aa28de27 | 534 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 535 | |
ec6347bb DW |
536 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
537 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 538 | { |
96d4f267 | 539 | if (access_ok(to, n)) { |
d0ef4c36 | 540 | instrument_copy_to_user(to, from, n); |
ec6347bb | 541 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
542 | } |
543 | return n; | |
544 | } | |
545 | ||
ec6347bb | 546 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
547 | struct iov_iter *i) |
548 | { | |
8fad7767 AV |
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; | |
ca146f6f DW |
556 | |
557 | if (!sanity(i)) | |
558 | return 0; | |
559 | ||
8fad7767 AV |
560 | while (bytes) { |
561 | struct page *page = append_pipe(i, bytes, &off); | |
ca146f6f | 562 | unsigned long rem; |
8fad7767 AV |
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); | |
2a510a74 AV |
569 | rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); |
570 | chunk -= rem; | |
571 | kunmap_local(p); | |
8fad7767 AV |
572 | xfer += chunk; |
573 | bytes -= chunk; | |
c3497fd0 | 574 | if (rem) { |
8fad7767 | 575 | iov_iter_revert(i, rem); |
ca146f6f | 576 | break; |
c3497fd0 | 577 | } |
2a510a74 | 578 | } |
ca146f6f DW |
579 | return xfer; |
580 | } | |
581 | ||
bf3eeb9b | 582 | /** |
ec6347bb | 583 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
584 | * @addr: source kernel address |
585 | * @bytes: total transfer length | |
44e55997 | 586 | * @i: destination iterator |
bf3eeb9b | 587 | * |
ec6347bb DW |
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. | |
bf3eeb9b | 592 | * |
ec6347bb | 593 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
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. | |
44e55997 RD |
604 | * |
605 | * Return: number of bytes copied (may be %0) | |
bf3eeb9b | 606 | */ |
ec6347bb | 607 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e | 608 | { |
00e23707 | 609 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 610 | return copy_mc_pipe_to_iter(addr, bytes, i); |
fcb14cb1 | 611 | if (user_backed_iter(i)) |
8780356e | 612 | might_fault(); |
7baa5099 AV |
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) | |
8780356e DW |
616 | ) |
617 | ||
618 | return bytes; | |
619 | } | |
ec6347bb DW |
620 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
621 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 622 | |
aa28de27 | 623 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 624 | { |
00e23707 | 625 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
626 | WARN_ON(1); |
627 | return 0; | |
628 | } | |
fcb14cb1 | 629 | if (user_backed_iter(i)) |
09fc68dc | 630 | might_fault(); |
7baa5099 AV |
631 | iterate_and_advance(i, bytes, base, len, off, |
632 | copyin(addr + off, base, len), | |
633 | memcpy(addr + off, base, len) | |
0dbca9a4 AV |
634 | ) |
635 | ||
636 | return bytes; | |
c35e0248 | 637 | } |
aa28de27 | 638 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 639 | |
aa28de27 | 640 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 | 641 | { |
00e23707 | 642 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
643 | WARN_ON(1); |
644 | return 0; | |
645 | } | |
7baa5099 AV |
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) | |
aa583096 AV |
649 | ) |
650 | ||
651 | return bytes; | |
652 | } | |
aa28de27 | 653 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 654 | |
0aed55af | 655 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
656 | /** |
657 | * _copy_from_iter_flushcache - write destination through cpu cache | |
658 | * @addr: destination kernel address | |
659 | * @bytes: total transfer length | |
44e55997 | 660 | * @i: source iterator |
abd08d7d DW |
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. | |
44e55997 RD |
669 | * |
670 | * Return: number of bytes copied (may be %0) | |
abd08d7d | 671 | */ |
6a37e940 | 672 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af | 673 | { |
00e23707 | 674 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
675 | WARN_ON(1); |
676 | return 0; | |
677 | } | |
7baa5099 AV |
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) | |
0aed55af DW |
681 | ) |
682 | ||
683 | return bytes; | |
684 | } | |
6a37e940 | 685 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
686 | #endif |
687 | ||
72e809ed AV |
688 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
689 | { | |
6daef95b ED |
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; | |
a90bcb86 | 705 | |
a50b854e | 706 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
707 | return true; |
708 | WARN_ON(1); | |
709 | return false; | |
710 | } | |
cbbd26b8 | 711 | |
08aa6479 AV |
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; | |
f0f6b614 AV |
718 | if (unlikely(iov_iter_is_pipe(i))) |
719 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
08aa6479 AV |
720 | page += offset / PAGE_SIZE; // first subpage |
721 | offset %= PAGE_SIZE; | |
722 | while (1) { | |
f0f6b614 AV |
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); | |
08aa6479 AV |
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 | } | |
62a8067a AV |
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 | { | |
c03f05f1 AV |
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) { | |
55ca375c | 750 | void *kaddr = kmap_local_page(page); |
c03f05f1 AV |
751 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
752 | n = _copy_from_iter(kaddr + offset, n, i); | |
55ca375c | 753 | kunmap_local(kaddr); |
c03f05f1 AV |
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 | } | |
28f38db7 | 763 | } |
c03f05f1 | 764 | return res; |
62a8067a AV |
765 | } |
766 | EXPORT_SYMBOL(copy_page_from_iter); | |
767 | ||
241699cd AV |
768 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
769 | { | |
8fad7767 | 770 | unsigned int chunk, off; |
241699cd | 771 | |
8fad7767 AV |
772 | if (unlikely(bytes > i->count)) |
773 | bytes = i->count; | |
774 | if (unlikely(!bytes)) | |
241699cd AV |
775 | return 0; |
776 | ||
8fad7767 | 777 | if (!sanity(i)) |
241699cd AV |
778 | return 0; |
779 | ||
8fad7767 AV |
780 | for (size_t n = bytes; n; n -= chunk) { |
781 | struct page *page = append_pipe(i, n, &off); | |
782 | char *p; | |
783 | ||
784 | if (!page) | |
785 | return bytes - n; | |
786 | chunk = min_t(size_t, n, PAGE_SIZE - off); | |
787 | p = kmap_local_page(page); | |
893839fd AV |
788 | memset(p + off, 0, chunk); |
789 | kunmap_local(p); | |
8fad7767 | 790 | } |
241699cd AV |
791 | return bytes; |
792 | } | |
793 | ||
c35e0248 MW |
794 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
795 | { | |
00e23707 | 796 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 797 | return pipe_zero(bytes, i); |
7baa5099 AV |
798 | iterate_and_advance(i, bytes, base, len, count, |
799 | clear_user(base, len), | |
800 | memset(base, 0, len) | |
8442fa46 AV |
801 | ) |
802 | ||
803 | return bytes; | |
c35e0248 MW |
804 | } |
805 | EXPORT_SYMBOL(iov_iter_zero); | |
806 | ||
f0b65f39 AV |
807 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
808 | struct iov_iter *i) | |
62a8067a | 809 | { |
04a31165 | 810 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
811 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
812 | kunmap_atomic(kaddr); | |
813 | return 0; | |
814 | } | |
9ea9ce04 | 815 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
816 | kunmap_atomic(kaddr); |
817 | WARN_ON(1); | |
818 | return 0; | |
819 | } | |
7baa5099 AV |
820 | iterate_and_advance(i, bytes, base, len, off, |
821 | copyin(p + off, base, len), | |
822 | memcpy(p + off, base, len) | |
04a31165 AV |
823 | ) |
824 | kunmap_atomic(kaddr); | |
825 | return bytes; | |
62a8067a | 826 | } |
f0b65f39 | 827 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 828 | |
241699cd AV |
829 | static void pipe_advance(struct iov_iter *i, size_t size) |
830 | { | |
831 | struct pipe_inode_info *pipe = i->pipe; | |
10f525a8 | 832 | int off = i->last_offset; |
8cefc107 | 833 | |
2c855de9 AV |
834 | if (!off && !size) { |
835 | pipe_discard_from(pipe, i->start_head); // discard everything | |
836 | return; | |
837 | } | |
838 | i->count -= size; | |
839 | while (1) { | |
840 | struct pipe_buffer *buf = pipe_buf(pipe, i->head); | |
241699cd | 841 | if (off) /* make it relative to the beginning of buffer */ |
10f525a8 | 842 | size += abs(off) - buf->offset; |
2c855de9 AV |
843 | if (size <= buf->len) { |
844 | buf->len = size; | |
10f525a8 | 845 | i->last_offset = last_offset(buf); |
2c855de9 | 846 | break; |
241699cd | 847 | } |
2c855de9 AV |
848 | size -= buf->len; |
849 | i->head++; | |
850 | off = 0; | |
241699cd | 851 | } |
2c855de9 | 852 | pipe_discard_from(pipe, i->head + 1); // discard everything past this one |
241699cd AV |
853 | } |
854 | ||
54c8195b PB |
855 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
856 | { | |
18fa9af7 | 857 | const struct bio_vec *bvec, *end; |
54c8195b | 858 | |
18fa9af7 AV |
859 | if (!i->count) |
860 | return; | |
861 | i->count -= size; | |
862 | ||
863 | size += i->iov_offset; | |
54c8195b | 864 | |
18fa9af7 AV |
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; | |
54c8195b PB |
873 | } |
874 | ||
185ac4d4 AV |
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 | ||
62a8067a AV |
894 | void iov_iter_advance(struct iov_iter *i, size_t size) |
895 | { | |
3b3fc051 AV |
896 | if (unlikely(i->count < size)) |
897 | size = i->count; | |
fcb14cb1 AV |
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))) { | |
185ac4d4 AV |
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)) { | |
241699cd | 907 | pipe_advance(i, size); |
185ac4d4 AV |
908 | } else if (iov_iter_is_discard(i)) { |
909 | i->count -= size; | |
54c8195b | 910 | } |
62a8067a AV |
911 | } |
912 | EXPORT_SYMBOL(iov_iter_advance); | |
913 | ||
27c0e374 AV |
914 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
915 | { | |
916 | if (!unroll) | |
917 | return; | |
5b47d59a AV |
918 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
919 | return; | |
27c0e374 | 920 | i->count += unroll; |
00e23707 | 921 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 922 | struct pipe_inode_info *pipe = i->pipe; |
92acdc4f AV |
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; | |
10f525a8 | 929 | i->last_offset = last_offset(b); |
92acdc4f AV |
930 | i->head = head; |
931 | return; | |
27c0e374 | 932 | } |
92acdc4f AV |
933 | unroll -= b->len; |
934 | pipe_buf_release(pipe, b); | |
935 | pipe->head--; | |
27c0e374 | 936 | } |
10f525a8 | 937 | i->last_offset = 0; |
92acdc4f | 938 | i->head = head; |
27c0e374 AV |
939 | return; |
940 | } | |
9ea9ce04 DH |
941 | if (unlikely(iov_iter_is_discard(i))) |
942 | return; | |
27c0e374 AV |
943 | if (unroll <= i->iov_offset) { |
944 | i->iov_offset -= unroll; | |
945 | return; | |
946 | } | |
947 | unroll -= i->iov_offset; | |
fcb14cb1 | 948 | if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { |
7ff50620 DH |
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)) { | |
27c0e374 AV |
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 | ||
62a8067a AV |
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 | { | |
28f38db7 AV |
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; | |
62a8067a AV |
993 | } |
994 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
995 | ||
aa563d7b | 996 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 997 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
998 | size_t count) |
999 | { | |
aa563d7b | 1000 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
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 | }; | |
abb78f87 AV |
1009 | } |
1010 | EXPORT_SYMBOL(iov_iter_kvec); | |
1011 | ||
aa563d7b | 1012 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1013 | const struct bio_vec *bvec, unsigned long nr_segs, |
1014 | size_t count) | |
1015 | { | |
aa563d7b | 1016 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
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 | }; | |
05afcb77 AV |
1025 | } |
1026 | EXPORT_SYMBOL(iov_iter_bvec); | |
1027 | ||
aa563d7b | 1028 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1029 | struct pipe_inode_info *pipe, |
1030 | size_t count) | |
1031 | { | |
aa563d7b | 1032 | BUG_ON(direction != READ); |
8cefc107 | 1033 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
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, | |
10f525a8 | 1040 | .last_offset = 0, |
8cd54c1c AV |
1041 | .count = count |
1042 | }; | |
241699cd AV |
1043 | } |
1044 | EXPORT_SYMBOL(iov_iter_pipe); | |
1045 | ||
7ff50620 DH |
1046 | /** |
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); | |
8cd54c1c AV |
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 | }; | |
7ff50620 DH |
1071 | } |
1072 | EXPORT_SYMBOL(iov_iter_xarray); | |
1073 | ||
9ea9ce04 DH |
1074 | /** |
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); | |
8cd54c1c AV |
1086 | *i = (struct iov_iter){ |
1087 | .iter_type = ITER_DISCARD, | |
1088 | .data_source = false, | |
1089 | .count = count, | |
1090 | .iov_offset = 0 | |
1091 | }; | |
9ea9ce04 DH |
1092 | } |
1093 | EXPORT_SYMBOL(iov_iter_discard); | |
1094 | ||
cfa320f7 KB |
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 | { | |
fcb14cb1 AV |
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 | ||
cfa320f7 KB |
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)) { | |
cfa320f7 KB |
1171 | size_t size = i->count; |
1172 | ||
1173 | if (size & len_mask) | |
1174 | return false; | |
10f525a8 AV |
1175 | if (size && i->last_offset > 0) { |
1176 | if (i->last_offset & addr_mask) | |
cfa320f7 KB |
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 | ||
9221d2e3 | 1194 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1195 | { |
04a31165 AV |
1196 | unsigned long res = 0; |
1197 | size_t size = i->count; | |
9221d2e3 AV |
1198 | size_t skip = i->iov_offset; |
1199 | unsigned k; | |
1200 | ||
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 | } | |
04a31165 | 1215 | |
9221d2e3 AV |
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 | { | |
fcb14cb1 AV |
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 | ||
9221d2e3 AV |
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)) { | |
9221d2e3 | 1253 | size_t size = i->count; |
e0ff126e | 1254 | |
10f525a8 AV |
1255 | if (size && i->last_offset > 0) |
1256 | return size | i->last_offset; | |
241699cd AV |
1257 | return size; |
1258 | } | |
9221d2e3 AV |
1259 | |
1260 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1261 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1262 | |
1263 | return 0; | |
62a8067a AV |
1264 | } |
1265 | EXPORT_SYMBOL(iov_iter_alignment); | |
1266 | ||
357f435d AV |
1267 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1268 | { | |
33844e66 | 1269 | unsigned long res = 0; |
610c7a71 | 1270 | unsigned long v = 0; |
357f435d | 1271 | size_t size = i->count; |
610c7a71 | 1272 | unsigned k; |
357f435d | 1273 | |
fcb14cb1 AV |
1274 | if (iter_is_ubuf(i)) |
1275 | return 0; | |
1276 | ||
610c7a71 | 1277 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1278 | return ~0U; |
241699cd | 1279 | |
610c7a71 AV |
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 | } | |
33844e66 | 1291 | return res; |
357f435d AV |
1292 | } |
1293 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1294 | ||
3cf42da3 AV |
1295 | static int want_pages_array(struct page ***res, size_t size, |
1296 | size_t start, unsigned int maxpages) | |
acbdeb83 | 1297 | { |
3cf42da3 AV |
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; | |
acbdeb83 AV |
1309 | } |
1310 | ||
241699cd | 1311 | static ssize_t pipe_get_pages(struct iov_iter *i, |
acbdeb83 | 1312 | struct page ***pages, size_t maxsize, unsigned maxpages, |
241699cd AV |
1313 | size_t *start) |
1314 | { | |
746de1f8 | 1315 | unsigned int npages, count, off, chunk; |
acbdeb83 | 1316 | struct page **p; |
746de1f8 | 1317 | size_t left; |
241699cd AV |
1318 | |
1319 | if (!sanity(i)) | |
1320 | return -EFAULT; | |
1321 | ||
12d426ab | 1322 | *start = off = pipe_npages(i, &npages); |
3cf42da3 AV |
1323 | if (!npages) |
1324 | return -EFAULT; | |
1325 | count = want_pages_array(pages, maxsize, off, min(npages, maxpages)); | |
1326 | if (!count) | |
1327 | return -ENOMEM; | |
acbdeb83 | 1328 | p = *pages; |
746de1f8 AV |
1329 | for (npages = 0, left = maxsize ; npages < count; npages++, left -= chunk) { |
1330 | struct page *page = append_pipe(i, left, &off); | |
85200084 AV |
1331 | if (!page) |
1332 | break; | |
746de1f8 | 1333 | chunk = min_t(size_t, left, PAGE_SIZE - off); |
85200084 | 1334 | get_page(*p++ = page); |
85200084 AV |
1335 | } |
1336 | if (!npages) | |
1337 | return -EFAULT; | |
746de1f8 | 1338 | return maxsize - left; |
241699cd AV |
1339 | } |
1340 | ||
7ff50620 DH |
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, | |
68fe506f | 1369 | struct page ***pages, size_t maxsize, |
7ff50620 DH |
1370 | unsigned maxpages, size_t *_start_offset) |
1371 | { | |
3cf42da3 AV |
1372 | unsigned nr, offset, count; |
1373 | pgoff_t index; | |
7ff50620 DH |
1374 | loff_t pos; |
1375 | ||
7ff50620 DH |
1376 | pos = i->xarray_start + i->iov_offset; |
1377 | index = pos >> PAGE_SHIFT; | |
1378 | offset = pos & ~PAGE_MASK; | |
1379 | *_start_offset = offset; | |
1380 | ||
3cf42da3 AV |
1381 | count = want_pages_array(pages, maxsize, offset, maxpages); |
1382 | if (!count) | |
1383 | return -ENOMEM; | |
68fe506f | 1384 | nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); |
7ff50620 DH |
1385 | if (nr == 0) |
1386 | return 0; | |
1387 | ||
eba2d3d7 | 1388 | maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); |
310d9d5a AV |
1389 | i->iov_offset += maxsize; |
1390 | i->count -= maxsize; | |
eba2d3d7 | 1391 | return maxsize; |
7ff50620 DH |
1392 | } |
1393 | ||
fcb14cb1 | 1394 | /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ |
dd45ab9d | 1395 | static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) |
3d671ca6 AV |
1396 | { |
1397 | size_t skip; | |
1398 | long k; | |
1399 | ||
fcb14cb1 AV |
1400 | if (iter_is_ubuf(i)) |
1401 | return (unsigned long)i->ubuf + i->iov_offset; | |
1402 | ||
3d671ca6 | 1403 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { |
3d671ca6 AV |
1404 | size_t len = i->iov[k].iov_len - skip; |
1405 | ||
1406 | if (unlikely(!len)) | |
1407 | continue; | |
59dbd7d0 AV |
1408 | if (*size > len) |
1409 | *size = len; | |
dd45ab9d | 1410 | return (unsigned long)i->iov[k].iov_base + skip; |
3d671ca6 AV |
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, | |
59dbd7d0 | 1417 | size_t *size, size_t *start) |
3d671ca6 AV |
1418 | { |
1419 | struct page *page; | |
1420 | size_t skip = i->iov_offset, len; | |
1421 | ||
1422 | len = i->bvec->bv_len - skip; | |
59dbd7d0 AV |
1423 | if (*size > len) |
1424 | *size = len; | |
3d671ca6 AV |
1425 | skip += i->bvec->bv_offset; |
1426 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
dda8e5d1 | 1427 | *start = skip % PAGE_SIZE; |
3d671ca6 AV |
1428 | return page; |
1429 | } | |
1430 | ||
451c0ba9 AV |
1431 | static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, |
1432 | struct page ***pages, size_t maxsize, | |
1433 | unsigned int maxpages, size_t *start) | |
62a8067a | 1434 | { |
3cf42da3 | 1435 | unsigned int n; |
3d671ca6 | 1436 | |
e5393fae AV |
1437 | if (maxsize > i->count) |
1438 | maxsize = i->count; | |
451c0ba9 | 1439 | if (!maxsize) |
3d671ca6 | 1440 | return 0; |
7392ed17 AV |
1441 | if (maxsize > MAX_RW_COUNT) |
1442 | maxsize = MAX_RW_COUNT; | |
e5393fae | 1443 | |
fcb14cb1 | 1444 | if (likely(user_backed_iter(i))) { |
3337ab08 | 1445 | unsigned int gup_flags = 0; |
3d671ca6 | 1446 | unsigned long addr; |
3cf42da3 | 1447 | int res; |
e5393fae | 1448 | |
3337ab08 AG |
1449 | if (iov_iter_rw(i) != WRITE) |
1450 | gup_flags |= FOLL_WRITE; | |
1451 | if (i->nofault) | |
1452 | gup_flags |= FOLL_NOFAULT; | |
1453 | ||
dd45ab9d AV |
1454 | addr = first_iovec_segment(i, &maxsize); |
1455 | *start = addr % PAGE_SIZE; | |
1456 | addr &= PAGE_MASK; | |
3cf42da3 AV |
1457 | n = want_pages_array(pages, maxsize, *start, maxpages); |
1458 | if (!n) | |
1459 | return -ENOMEM; | |
451c0ba9 | 1460 | res = get_user_pages_fast(addr, n, gup_flags, *pages); |
814a6674 | 1461 | if (unlikely(res <= 0)) |
e5393fae | 1462 | return res; |
eba2d3d7 AV |
1463 | maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - *start); |
1464 | iov_iter_advance(i, maxsize); | |
1465 | return maxsize; | |
3d671ca6 AV |
1466 | } |
1467 | if (iov_iter_is_bvec(i)) { | |
451c0ba9 | 1468 | struct page **p; |
3d671ca6 AV |
1469 | struct page *page; |
1470 | ||
59dbd7d0 | 1471 | page = first_bvec_segment(i, &maxsize, start); |
3cf42da3 AV |
1472 | n = want_pages_array(pages, maxsize, *start, maxpages); |
1473 | if (!n) | |
1474 | return -ENOMEM; | |
451c0ba9 | 1475 | p = *pages; |
dda8e5d1 | 1476 | for (int k = 0; k < n; k++) |
eba2d3d7 AV |
1477 | get_page(p[k] = page + k); |
1478 | maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); | |
310d9d5a AV |
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 | } | |
eba2d3d7 | 1486 | return maxsize; |
3d671ca6 AV |
1487 | } |
1488 | if (iov_iter_is_pipe(i)) | |
451c0ba9 | 1489 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
3d671ca6 | 1490 | if (iov_iter_is_xarray(i)) |
451c0ba9 | 1491 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); |
3d671ca6 | 1492 | return -EFAULT; |
62a8067a | 1493 | } |
62a8067a | 1494 | |
eba2d3d7 | 1495 | ssize_t iov_iter_get_pages2(struct iov_iter *i, |
451c0ba9 | 1496 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1497 | size_t *start) |
1498 | { | |
451c0ba9 | 1499 | if (!maxpages) |
3d671ca6 | 1500 | return 0; |
451c0ba9 | 1501 | BUG_ON(!pages); |
3d671ca6 | 1502 | |
451c0ba9 | 1503 | return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); |
62a8067a | 1504 | } |
eba2d3d7 | 1505 | EXPORT_SYMBOL(iov_iter_get_pages2); |
91329559 | 1506 | |
eba2d3d7 | 1507 | ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, |
91329559 AV |
1508 | struct page ***pages, size_t maxsize, |
1509 | size_t *start) | |
1510 | { | |
1511 | ssize_t len; | |
1512 | ||
1513 | *pages = NULL; | |
1514 | ||
451c0ba9 | 1515 | len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); |
91329559 AV |
1516 | if (len <= 0) { |
1517 | kvfree(*pages); | |
1518 | *pages = NULL; | |
1519 | } | |
1520 | return len; | |
1521 | } | |
eba2d3d7 | 1522 | EXPORT_SYMBOL(iov_iter_get_pages_alloc2); |
62a8067a | 1523 | |
a604ec7e AV |
1524 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1525 | struct iov_iter *i) | |
1526 | { | |
a604ec7e | 1527 | __wsum sum, next; |
a604ec7e | 1528 | sum = *csum; |
9ea9ce04 | 1529 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1530 | WARN_ON(1); |
1531 | return 0; | |
1532 | } | |
7baa5099 AV |
1533 | iterate_and_advance(i, bytes, base, len, off, ({ |
1534 | next = csum_and_copy_from_user(base, addr + off, len); | |
2495bdcc | 1535 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1536 | next ? 0 : len; |
a604ec7e | 1537 | }), ({ |
7baa5099 | 1538 | sum = csum_and_memcpy(addr + off, base, len, sum, off); |
a604ec7e AV |
1539 | }) |
1540 | ) | |
1541 | *csum = sum; | |
1542 | return bytes; | |
1543 | } | |
1544 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1545 | ||
52cbd23a | 1546 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1547 | struct iov_iter *i) |
1548 | { | |
52cbd23a | 1549 | struct csum_state *csstate = _csstate; |
a604ec7e | 1550 | __wsum sum, next; |
78e1f386 | 1551 | |
78e1f386 | 1552 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1553 | WARN_ON(1); /* for now */ |
1554 | return 0; | |
1555 | } | |
6852df12 AV |
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, ({ | |
7baa5099 | 1561 | next = csum_and_copy_to_user(addr + off, base, len); |
2495bdcc | 1562 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1563 | next ? 0 : len; |
a604ec7e | 1564 | }), ({ |
7baa5099 | 1565 | sum = csum_and_memcpy(base, addr + off, len, sum, off); |
a604ec7e AV |
1566 | }) |
1567 | ) | |
594e450b AV |
1568 | csstate->csum = csum_shift(sum, csstate->off); |
1569 | csstate->off += bytes; | |
a604ec7e AV |
1570 | return bytes; |
1571 | } | |
1572 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1573 | ||
d05f4435 SG |
1574 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1575 | struct iov_iter *i) | |
1576 | { | |
7999096f | 1577 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
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; | |
27fad74a Y |
1587 | #else |
1588 | return 0; | |
1589 | #endif | |
d05f4435 SG |
1590 | } |
1591 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1592 | ||
66531c65 | 1593 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1594 | { |
66531c65 AV |
1595 | size_t skip = i->iov_offset, size = i->count; |
1596 | const struct iovec *p; | |
e0f2dc40 AV |
1597 | int npages = 0; |
1598 | ||
66531c65 AV |
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); | |
e0f2dc40 | 1602 | |
66531c65 AV |
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; | |
fcb14cb1 AV |
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 | } | |
66531c65 AV |
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)) { | |
66531c65 | 1646 | int npages; |
241699cd AV |
1647 | |
1648 | if (!sanity(i)) | |
1649 | return 0; | |
1650 | ||
12d426ab | 1651 | pipe_npages(i, &npages); |
66531c65 AV |
1652 | return min(npages, maxpages); |
1653 | } | |
1654 | if (iov_iter_is_xarray(i)) { | |
e4f8df86 AV |
1655 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1656 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1657 | return min(npages, maxpages); |
1658 | } | |
1659 | return 0; | |
62a8067a | 1660 | } |
f67da30c | 1661 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1662 | |
1663 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1664 | { | |
1665 | *new = *old; | |
00e23707 | 1666 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1667 | WARN_ON(1); |
1668 | return NULL; | |
1669 | } | |
00e23707 | 1670 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1671 | return new->bvec = kmemdup(new->bvec, |
1672 | new->nr_segs * sizeof(struct bio_vec), | |
1673 | flags); | |
fcb14cb1 | 1674 | else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) |
4b8164b9 AV |
1675 | /* iovec and kvec have identical layout */ |
1676 | return new->iov = kmemdup(new->iov, | |
1677 | new->nr_segs * sizeof(struct iovec), | |
1678 | flags); | |
fcb14cb1 | 1679 | return NULL; |
4b8164b9 AV |
1680 | } |
1681 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1682 | |
bfdc5970 CH |
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 | ||
a959a978 | 1690 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
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) | |
fb041b59 DL |
1717 | { |
1718 | unsigned long seg; | |
fb041b59 | 1719 | |
bfdc5970 CH |
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; | |
fb041b59 DL |
1725 | } |
1726 | ||
bfdc5970 CH |
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; | |
1736 | ||
fb041b59 | 1737 | /* |
bfdc5970 CH |
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 | |
1740 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1741 | */ |
bfdc5970 CH |
1742 | if (nr_segs == 0) |
1743 | return iov; | |
1744 | if (nr_segs > UIO_MAXIOV) | |
1745 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1746 | if (nr_segs > fast_segs) { |
1747 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1748 | if (!iov) |
1749 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1750 | } |
bfdc5970 CH |
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); | |
fb041b59 DL |
1777 | } |
1778 | ||
1779 | /* | |
bfdc5970 CH |
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. | |
fb041b59 DL |
1783 | * |
1784 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
1785 | * overflow case. | |
1786 | */ | |
fb041b59 | 1787 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
1788 | ssize_t len = (ssize_t)iov[seg].iov_len; |
1789 | ||
bfdc5970 CH |
1790 | if (!access_ok(iov[seg].iov_base, len)) { |
1791 | if (iov != *iovp) | |
1792 | kfree(iov); | |
1793 | *iovp = NULL; | |
1794 | return -EFAULT; | |
fb041b59 | 1795 | } |
bfdc5970 CH |
1796 | |
1797 | if (len > MAX_RW_COUNT - total_len) { | |
1798 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
1799 | iov[seg].iov_len = len; |
1800 | } | |
bfdc5970 | 1801 | total_len += len; |
fb041b59 | 1802 | } |
bfdc5970 CH |
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; | |
fb041b59 DL |
1810 | } |
1811 | ||
ffecee4f VN |
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. | |
bfdc5970 | 1818 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
1819 | * @nr_segs: Number of elements in userspace array. |
1820 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 1821 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
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 | * | |
87e5e6da | 1832 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 1833 | */ |
bfdc5970 | 1834 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 1835 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 1836 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 1837 | { |
89cd35c5 CH |
1838 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
1839 | in_compat_syscall()); | |
bc917be8 AV |
1840 | } |
1841 | EXPORT_SYMBOL(import_iovec); | |
1842 | ||
bc917be8 AV |
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; | |
96d4f267 | 1848 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
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 | } | |
e1267585 | 1856 | EXPORT_SYMBOL(import_single_range); |
8fb0f47a JA |
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)) && | |
fcb14cb1 | 1873 | !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) |
8fb0f47a JA |
1874 | return; |
1875 | i->iov_offset = state->iov_offset; | |
1876 | i->count = state->count; | |
fcb14cb1 AV |
1877 | if (iter_is_ubuf(i)) |
1878 | return; | |
8fb0f47a JA |
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 | } |