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 | { | |
4d0e9df5 AL |
177 | if (should_fail_usercopy()) |
178 | return n; | |
96d4f267 | 179 | if (access_ok(from, n)) { |
d0ef4c36 | 180 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
181 | n = raw_copy_from_user(to, from, n); |
182 | } | |
183 | return n; | |
184 | } | |
185 | ||
2dcedb2a AV |
186 | static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, |
187 | unsigned int slot) | |
188 | { | |
189 | return &pipe->bufs[slot & (pipe->ring_size - 1)]; | |
190 | } | |
191 | ||
241699cd AV |
192 | #ifdef PIPE_PARANOIA |
193 | static bool sanity(const struct iov_iter *i) | |
194 | { | |
195 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
196 | unsigned int p_head = pipe->head; |
197 | unsigned int p_tail = pipe->tail; | |
8cefc107 DH |
198 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); |
199 | unsigned int i_head = i->head; | |
200 | unsigned int idx; | |
201 | ||
10f525a8 | 202 | if (i->last_offset) { |
241699cd | 203 | struct pipe_buffer *p; |
8cefc107 | 204 | if (unlikely(p_occupancy == 0)) |
241699cd | 205 | goto Bad; // pipe must be non-empty |
8cefc107 | 206 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
207 | goto Bad; // must be at the last buffer... |
208 | ||
2dcedb2a | 209 | p = pipe_buf(pipe, i_head); |
10f525a8 | 210 | if (unlikely(p->offset + p->len != abs(i->last_offset))) |
241699cd AV |
211 | goto Bad; // ... at the end of segment |
212 | } else { | |
8cefc107 | 213 | if (i_head != p_head) |
241699cd AV |
214 | goto Bad; // must be right after the last buffer |
215 | } | |
216 | return true; | |
217 | Bad: | |
10f525a8 | 218 | printk(KERN_ERR "idx = %d, offset = %d\n", i_head, i->last_offset); |
8cefc107 DH |
219 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", |
220 | p_head, p_tail, pipe->ring_size); | |
221 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
222 | printk(KERN_ERR "[%p %p %d %d]\n", |
223 | pipe->bufs[idx].ops, | |
224 | pipe->bufs[idx].page, | |
225 | pipe->bufs[idx].offset, | |
226 | pipe->bufs[idx].len); | |
227 | WARN_ON(1); | |
228 | return false; | |
229 | } | |
230 | #else | |
231 | #define sanity(i) true | |
232 | #endif | |
233 | ||
47b7fcae AV |
234 | static struct page *push_anon(struct pipe_inode_info *pipe, unsigned size) |
235 | { | |
236 | struct page *page = alloc_page(GFP_USER); | |
237 | if (page) { | |
238 | struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); | |
239 | *buf = (struct pipe_buffer) { | |
240 | .ops = &default_pipe_buf_ops, | |
241 | .page = page, | |
242 | .offset = 0, | |
243 | .len = size | |
244 | }; | |
245 | } | |
246 | return page; | |
247 | } | |
248 | ||
249 | static void push_page(struct pipe_inode_info *pipe, struct page *page, | |
250 | unsigned int offset, unsigned int size) | |
251 | { | |
252 | struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); | |
253 | *buf = (struct pipe_buffer) { | |
254 | .ops = &page_cache_pipe_buf_ops, | |
255 | .page = page, | |
256 | .offset = offset, | |
257 | .len = size | |
258 | }; | |
259 | get_page(page); | |
260 | } | |
261 | ||
10f525a8 | 262 | static inline int last_offset(const struct pipe_buffer *buf) |
8fad7767 | 263 | { |
10f525a8 AV |
264 | if (buf->ops == &default_pipe_buf_ops) |
265 | return buf->len; // buf->offset is 0 for those | |
266 | else | |
267 | return -(buf->offset + buf->len); | |
8fad7767 AV |
268 | } |
269 | ||
270 | static struct page *append_pipe(struct iov_iter *i, size_t size, | |
271 | unsigned int *off) | |
272 | { | |
273 | struct pipe_inode_info *pipe = i->pipe; | |
10f525a8 | 274 | int offset = i->last_offset; |
8fad7767 AV |
275 | struct pipe_buffer *buf; |
276 | struct page *page; | |
277 | ||
10f525a8 AV |
278 | if (offset > 0 && offset < PAGE_SIZE) { |
279 | // some space in the last buffer; add to it | |
8fad7767 | 280 | buf = pipe_buf(pipe, pipe->head - 1); |
10f525a8 AV |
281 | size = min_t(size_t, size, PAGE_SIZE - offset); |
282 | buf->len += size; | |
283 | i->last_offset += size; | |
284 | i->count -= size; | |
285 | *off = offset; | |
286 | return buf->page; | |
8fad7767 AV |
287 | } |
288 | // OK, we need a new buffer | |
289 | *off = 0; | |
290 | size = min_t(size_t, size, PAGE_SIZE); | |
291 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) | |
292 | return NULL; | |
293 | page = push_anon(pipe, size); | |
294 | if (!page) | |
295 | return NULL; | |
296 | i->head = pipe->head - 1; | |
10f525a8 | 297 | i->last_offset = size; |
8fad7767 AV |
298 | i->count -= size; |
299 | return page; | |
300 | } | |
301 | ||
241699cd AV |
302 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
303 | struct iov_iter *i) | |
304 | { | |
305 | struct pipe_inode_info *pipe = i->pipe; | |
47b7fcae | 306 | unsigned int head = pipe->head; |
241699cd AV |
307 | |
308 | if (unlikely(bytes > i->count)) | |
309 | bytes = i->count; | |
310 | ||
311 | if (unlikely(!bytes)) | |
312 | return 0; | |
313 | ||
314 | if (!sanity(i)) | |
315 | return 0; | |
316 | ||
10f525a8 | 317 | if (offset && i->last_offset == -offset) { // could we merge it? |
47b7fcae AV |
318 | struct pipe_buffer *buf = pipe_buf(pipe, head - 1); |
319 | if (buf->page == page) { | |
241699cd | 320 | buf->len += bytes; |
10f525a8 | 321 | i->last_offset -= bytes; |
47b7fcae AV |
322 | i->count -= bytes; |
323 | return bytes; | |
241699cd | 324 | } |
241699cd | 325 | } |
47b7fcae | 326 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
241699cd | 327 | return 0; |
8cefc107 | 328 | |
47b7fcae | 329 | push_page(pipe, page, offset, bytes); |
10f525a8 | 330 | i->last_offset = -(offset + bytes); |
47b7fcae | 331 | i->head = head; |
241699cd AV |
332 | i->count -= bytes; |
333 | return bytes; | |
334 | } | |
335 | ||
171a0203 | 336 | /* |
a6294593 AG |
337 | * fault_in_iov_iter_readable - fault in iov iterator for reading |
338 | * @i: iterator | |
339 | * @size: maximum length | |
340 | * | |
171a0203 | 341 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
a6294593 AG |
342 | * @size. For each iovec, fault in each page that constitutes the iovec. |
343 | * | |
344 | * Returns the number of bytes not faulted in (like copy_to_user() and | |
345 | * copy_from_user()). | |
171a0203 | 346 | * |
a6294593 | 347 | * Always returns 0 for non-userspace iterators. |
171a0203 | 348 | */ |
a6294593 | 349 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) |
171a0203 | 350 | { |
fcb14cb1 AV |
351 | if (iter_is_ubuf(i)) { |
352 | size_t n = min(size, iov_iter_count(i)); | |
353 | n -= fault_in_readable(i->ubuf + i->iov_offset, n); | |
354 | return size - n; | |
355 | } else if (iter_is_iovec(i)) { | |
a6294593 | 356 | size_t count = min(size, iov_iter_count(i)); |
8409a0d2 AV |
357 | const struct iovec *p; |
358 | size_t skip; | |
359 | ||
a6294593 AG |
360 | size -= count; |
361 | for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { | |
362 | size_t len = min(count, p->iov_len - skip); | |
363 | size_t ret; | |
8409a0d2 AV |
364 | |
365 | if (unlikely(!len)) | |
366 | continue; | |
a6294593 AG |
367 | ret = fault_in_readable(p->iov_base + skip, len); |
368 | count -= len - ret; | |
369 | if (ret) | |
370 | break; | |
8409a0d2 | 371 | } |
a6294593 | 372 | return count + size; |
171a0203 AA |
373 | } |
374 | return 0; | |
375 | } | |
a6294593 | 376 | EXPORT_SYMBOL(fault_in_iov_iter_readable); |
171a0203 | 377 | |
cdd591fc AG |
378 | /* |
379 | * fault_in_iov_iter_writeable - fault in iov iterator for writing | |
380 | * @i: iterator | |
381 | * @size: maximum length | |
382 | * | |
383 | * Faults in the iterator using get_user_pages(), i.e., without triggering | |
384 | * hardware page faults. This is primarily useful when we already know that | |
385 | * some or all of the pages in @i aren't in memory. | |
386 | * | |
387 | * Returns the number of bytes not faulted in, like copy_to_user() and | |
388 | * copy_from_user(). | |
389 | * | |
390 | * Always returns 0 for non-user-space iterators. | |
391 | */ | |
392 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) | |
393 | { | |
fcb14cb1 AV |
394 | if (iter_is_ubuf(i)) { |
395 | size_t n = min(size, iov_iter_count(i)); | |
396 | n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); | |
397 | return size - n; | |
398 | } else if (iter_is_iovec(i)) { | |
cdd591fc AG |
399 | size_t count = min(size, iov_iter_count(i)); |
400 | const struct iovec *p; | |
401 | size_t skip; | |
402 | ||
403 | size -= count; | |
404 | for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { | |
405 | size_t len = min(count, p->iov_len - skip); | |
406 | size_t ret; | |
407 | ||
408 | if (unlikely(!len)) | |
409 | continue; | |
410 | ret = fault_in_safe_writeable(p->iov_base + skip, len); | |
411 | count -= len - ret; | |
412 | if (ret) | |
413 | break; | |
414 | } | |
415 | return count + size; | |
416 | } | |
417 | return 0; | |
418 | } | |
419 | EXPORT_SYMBOL(fault_in_iov_iter_writeable); | |
420 | ||
aa563d7b | 421 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
422 | const struct iovec *iov, unsigned long nr_segs, |
423 | size_t count) | |
424 | { | |
aa563d7b | 425 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
426 | *i = (struct iov_iter) { |
427 | .iter_type = ITER_IOVEC, | |
3337ab08 | 428 | .nofault = false, |
fcb14cb1 | 429 | .user_backed = true, |
8cd54c1c AV |
430 | .data_source = direction, |
431 | .iov = iov, | |
432 | .nr_segs = nr_segs, | |
433 | .iov_offset = 0, | |
434 | .count = count | |
435 | }; | |
71d8e532 AV |
436 | } |
437 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 438 | |
12d426ab AV |
439 | // returns the offset in partial buffer (if any) |
440 | static inline unsigned int pipe_npages(const struct iov_iter *i, int *npages) | |
241699cd | 441 | { |
12d426ab AV |
442 | struct pipe_inode_info *pipe = i->pipe; |
443 | int used = pipe->head - pipe->tail; | |
10f525a8 | 444 | int off = i->last_offset; |
8cefc107 | 445 | |
12d426ab AV |
446 | *npages = max((int)pipe->max_usage - used, 0); |
447 | ||
10f525a8 | 448 | if (off > 0 && off < PAGE_SIZE) { // anon and not full |
12d426ab AV |
449 | (*npages)++; |
450 | return off; | |
241699cd | 451 | } |
12d426ab | 452 | return 0; |
241699cd AV |
453 | } |
454 | ||
241699cd AV |
455 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
456 | struct iov_iter *i) | |
457 | { | |
8fad7767 | 458 | unsigned int off, chunk; |
241699cd | 459 | |
8fad7767 AV |
460 | if (unlikely(bytes > i->count)) |
461 | bytes = i->count; | |
462 | if (unlikely(!bytes)) | |
241699cd AV |
463 | return 0; |
464 | ||
8fad7767 | 465 | if (!sanity(i)) |
241699cd | 466 | return 0; |
8fad7767 AV |
467 | |
468 | for (size_t n = bytes; n; n -= chunk) { | |
469 | struct page *page = append_pipe(i, n, &off); | |
470 | chunk = min_t(size_t, n, PAGE_SIZE - off); | |
471 | if (!page) | |
472 | return bytes - n; | |
473 | memcpy_to_page(page, off, addr, chunk); | |
241699cd | 474 | addr += chunk; |
8fad7767 | 475 | } |
241699cd AV |
476 | return bytes; |
477 | } | |
478 | ||
f9152895 AV |
479 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
480 | __wsum sum, size_t off) | |
481 | { | |
cc44c17b | 482 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
483 | return csum_block_add(sum, next, off); |
484 | } | |
485 | ||
78e1f386 | 486 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
6852df12 | 487 | struct iov_iter *i, __wsum *sump) |
78e1f386 | 488 | { |
6852df12 AV |
489 | __wsum sum = *sump; |
490 | size_t off = 0; | |
8fad7767 AV |
491 | unsigned int chunk, r; |
492 | ||
493 | if (unlikely(bytes > i->count)) | |
494 | bytes = i->count; | |
495 | if (unlikely(!bytes)) | |
496 | return 0; | |
78e1f386 AV |
497 | |
498 | if (!sanity(i)) | |
499 | return 0; | |
500 | ||
6852df12 | 501 | while (bytes) { |
8fad7767 AV |
502 | struct page *page = append_pipe(i, bytes, &r); |
503 | char *p; | |
504 | ||
505 | if (!page) | |
506 | break; | |
507 | chunk = min_t(size_t, bytes, PAGE_SIZE - r); | |
508 | p = kmap_local_page(page); | |
6852df12 | 509 | sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); |
2495bdcc | 510 | kunmap_local(p); |
78e1f386 | 511 | off += chunk; |
8fad7767 | 512 | bytes -= chunk; |
6852df12 AV |
513 | } |
514 | *sump = sum; | |
6852df12 | 515 | return off; |
78e1f386 AV |
516 | } |
517 | ||
aa28de27 | 518 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 519 | { |
00e23707 | 520 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 521 | return copy_pipe_to_iter(addr, bytes, i); |
fcb14cb1 | 522 | if (user_backed_iter(i)) |
09fc68dc | 523 | might_fault(); |
7baa5099 AV |
524 | iterate_and_advance(i, bytes, base, len, off, |
525 | copyout(base, addr + off, len), | |
526 | memcpy(base, addr + off, len) | |
3d4d3e48 | 527 | ) |
62a8067a | 528 | |
3d4d3e48 | 529 | return bytes; |
c35e0248 | 530 | } |
aa28de27 | 531 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 532 | |
ec6347bb DW |
533 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
534 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 535 | { |
96d4f267 | 536 | if (access_ok(to, n)) { |
d0ef4c36 | 537 | instrument_copy_to_user(to, from, n); |
ec6347bb | 538 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
539 | } |
540 | return n; | |
541 | } | |
542 | ||
ec6347bb | 543 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
544 | struct iov_iter *i) |
545 | { | |
8fad7767 AV |
546 | size_t xfer = 0; |
547 | unsigned int off, chunk; | |
548 | ||
549 | if (unlikely(bytes > i->count)) | |
550 | bytes = i->count; | |
551 | if (unlikely(!bytes)) | |
552 | return 0; | |
ca146f6f DW |
553 | |
554 | if (!sanity(i)) | |
555 | return 0; | |
556 | ||
8fad7767 AV |
557 | while (bytes) { |
558 | struct page *page = append_pipe(i, bytes, &off); | |
ca146f6f | 559 | unsigned long rem; |
8fad7767 AV |
560 | char *p; |
561 | ||
562 | if (!page) | |
563 | break; | |
564 | chunk = min_t(size_t, bytes, PAGE_SIZE - off); | |
565 | p = kmap_local_page(page); | |
2a510a74 AV |
566 | rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); |
567 | chunk -= rem; | |
568 | kunmap_local(p); | |
8fad7767 AV |
569 | xfer += chunk; |
570 | bytes -= chunk; | |
c3497fd0 | 571 | if (rem) { |
8fad7767 | 572 | iov_iter_revert(i, rem); |
ca146f6f | 573 | break; |
c3497fd0 | 574 | } |
2a510a74 | 575 | } |
ca146f6f DW |
576 | return xfer; |
577 | } | |
578 | ||
bf3eeb9b | 579 | /** |
ec6347bb | 580 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
581 | * @addr: source kernel address |
582 | * @bytes: total transfer length | |
44e55997 | 583 | * @i: destination iterator |
bf3eeb9b | 584 | * |
ec6347bb DW |
585 | * The pmem driver deploys this for the dax operation |
586 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
587 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
588 | * successfully copied. | |
bf3eeb9b | 589 | * |
ec6347bb | 590 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
591 | * |
592 | * * Typical tail/residue handling after a fault retries the copy | |
593 | * byte-by-byte until the fault happens again. Re-triggering machine | |
594 | * checks is potentially fatal so the implementation uses source | |
595 | * alignment and poison alignment assumptions to avoid re-triggering | |
596 | * hardware exceptions. | |
597 | * | |
598 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
599 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
600 | * a short copy. | |
44e55997 RD |
601 | * |
602 | * Return: number of bytes copied (may be %0) | |
bf3eeb9b | 603 | */ |
ec6347bb | 604 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e | 605 | { |
00e23707 | 606 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 607 | return copy_mc_pipe_to_iter(addr, bytes, i); |
fcb14cb1 | 608 | if (user_backed_iter(i)) |
8780356e | 609 | might_fault(); |
7baa5099 AV |
610 | __iterate_and_advance(i, bytes, base, len, off, |
611 | copyout_mc(base, addr + off, len), | |
612 | copy_mc_to_kernel(base, addr + off, len) | |
8780356e DW |
613 | ) |
614 | ||
615 | return bytes; | |
616 | } | |
ec6347bb DW |
617 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
618 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 619 | |
aa28de27 | 620 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 621 | { |
00e23707 | 622 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
623 | WARN_ON(1); |
624 | return 0; | |
625 | } | |
fcb14cb1 | 626 | if (user_backed_iter(i)) |
09fc68dc | 627 | might_fault(); |
7baa5099 AV |
628 | iterate_and_advance(i, bytes, base, len, off, |
629 | copyin(addr + off, base, len), | |
630 | memcpy(addr + off, base, len) | |
0dbca9a4 AV |
631 | ) |
632 | ||
633 | return bytes; | |
c35e0248 | 634 | } |
aa28de27 | 635 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 636 | |
aa28de27 | 637 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 | 638 | { |
00e23707 | 639 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
640 | WARN_ON(1); |
641 | return 0; | |
642 | } | |
7baa5099 AV |
643 | iterate_and_advance(i, bytes, base, len, off, |
644 | __copy_from_user_inatomic_nocache(addr + off, base, len), | |
645 | memcpy(addr + off, base, len) | |
aa583096 AV |
646 | ) |
647 | ||
648 | return bytes; | |
649 | } | |
aa28de27 | 650 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 651 | |
0aed55af | 652 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
653 | /** |
654 | * _copy_from_iter_flushcache - write destination through cpu cache | |
655 | * @addr: destination kernel address | |
656 | * @bytes: total transfer length | |
44e55997 | 657 | * @i: source iterator |
abd08d7d DW |
658 | * |
659 | * The pmem driver arranges for filesystem-dax to use this facility via | |
660 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
661 | * are flushed through the CPU cache. It is differentiated from | |
662 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
663 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
664 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
665 | * instructions that strand dirty-data in the cache. | |
44e55997 RD |
666 | * |
667 | * Return: number of bytes copied (may be %0) | |
abd08d7d | 668 | */ |
6a37e940 | 669 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af | 670 | { |
00e23707 | 671 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
672 | WARN_ON(1); |
673 | return 0; | |
674 | } | |
7baa5099 AV |
675 | iterate_and_advance(i, bytes, base, len, off, |
676 | __copy_from_user_flushcache(addr + off, base, len), | |
677 | memcpy_flushcache(addr + off, base, len) | |
0aed55af DW |
678 | ) |
679 | ||
680 | return bytes; | |
681 | } | |
6a37e940 | 682 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
683 | #endif |
684 | ||
72e809ed AV |
685 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
686 | { | |
6daef95b ED |
687 | struct page *head; |
688 | size_t v = n + offset; | |
689 | ||
690 | /* | |
691 | * The general case needs to access the page order in order | |
692 | * to compute the page size. | |
693 | * However, we mostly deal with order-0 pages and thus can | |
694 | * avoid a possible cache line miss for requests that fit all | |
695 | * page orders. | |
696 | */ | |
697 | if (n <= v && v <= PAGE_SIZE) | |
698 | return true; | |
699 | ||
700 | head = compound_head(page); | |
701 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 702 | |
a50b854e | 703 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
704 | return true; |
705 | WARN_ON(1); | |
706 | return false; | |
707 | } | |
cbbd26b8 | 708 | |
08aa6479 | 709 | static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
62a8067a AV |
710 | struct iov_iter *i) |
711 | { | |
59bb69c6 AV |
712 | if (unlikely(iov_iter_is_pipe(i))) { |
713 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
714 | } else { | |
c1d4d6a9 AV |
715 | void *kaddr = kmap_local_page(page); |
716 | size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); | |
717 | kunmap_local(kaddr); | |
d271524a | 718 | return wanted; |
28f38db7 | 719 | } |
62a8067a | 720 | } |
08aa6479 AV |
721 | |
722 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
723 | struct iov_iter *i) | |
724 | { | |
725 | size_t res = 0; | |
726 | if (unlikely(!page_copy_sane(page, offset, bytes))) | |
727 | return 0; | |
728 | page += offset / PAGE_SIZE; // first subpage | |
729 | offset %= PAGE_SIZE; | |
730 | while (1) { | |
731 | size_t n = __copy_page_to_iter(page, offset, | |
732 | min(bytes, (size_t)PAGE_SIZE - offset), i); | |
733 | res += n; | |
734 | bytes -= n; | |
735 | if (!bytes || !n) | |
736 | break; | |
737 | offset += n; | |
738 | if (offset == PAGE_SIZE) { | |
739 | page++; | |
740 | offset = 0; | |
741 | } | |
742 | } | |
743 | return res; | |
744 | } | |
62a8067a AV |
745 | EXPORT_SYMBOL(copy_page_to_iter); |
746 | ||
747 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
748 | struct iov_iter *i) | |
749 | { | |
59bb69c6 | 750 | if (page_copy_sane(page, offset, bytes)) { |
55ca375c | 751 | void *kaddr = kmap_local_page(page); |
aa28de27 | 752 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
55ca375c | 753 | kunmap_local(kaddr); |
d271524a | 754 | return wanted; |
28f38db7 | 755 | } |
28f38db7 | 756 | return 0; |
62a8067a AV |
757 | } |
758 | EXPORT_SYMBOL(copy_page_from_iter); | |
759 | ||
241699cd AV |
760 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
761 | { | |
8fad7767 | 762 | unsigned int chunk, off; |
241699cd | 763 | |
8fad7767 AV |
764 | if (unlikely(bytes > i->count)) |
765 | bytes = i->count; | |
766 | if (unlikely(!bytes)) | |
241699cd AV |
767 | return 0; |
768 | ||
8fad7767 | 769 | if (!sanity(i)) |
241699cd AV |
770 | return 0; |
771 | ||
8fad7767 AV |
772 | for (size_t n = bytes; n; n -= chunk) { |
773 | struct page *page = append_pipe(i, n, &off); | |
774 | char *p; | |
775 | ||
776 | if (!page) | |
777 | return bytes - n; | |
778 | chunk = min_t(size_t, n, PAGE_SIZE - off); | |
779 | p = kmap_local_page(page); | |
893839fd AV |
780 | memset(p + off, 0, chunk); |
781 | kunmap_local(p); | |
8fad7767 | 782 | } |
241699cd AV |
783 | return bytes; |
784 | } | |
785 | ||
c35e0248 MW |
786 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
787 | { | |
00e23707 | 788 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 789 | return pipe_zero(bytes, i); |
7baa5099 AV |
790 | iterate_and_advance(i, bytes, base, len, count, |
791 | clear_user(base, len), | |
792 | memset(base, 0, len) | |
8442fa46 AV |
793 | ) |
794 | ||
795 | return bytes; | |
c35e0248 MW |
796 | } |
797 | EXPORT_SYMBOL(iov_iter_zero); | |
798 | ||
f0b65f39 AV |
799 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
800 | struct iov_iter *i) | |
62a8067a | 801 | { |
04a31165 | 802 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
803 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
804 | kunmap_atomic(kaddr); | |
805 | return 0; | |
806 | } | |
9ea9ce04 | 807 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
808 | kunmap_atomic(kaddr); |
809 | WARN_ON(1); | |
810 | return 0; | |
811 | } | |
7baa5099 AV |
812 | iterate_and_advance(i, bytes, base, len, off, |
813 | copyin(p + off, base, len), | |
814 | memcpy(p + off, base, len) | |
04a31165 AV |
815 | ) |
816 | kunmap_atomic(kaddr); | |
817 | return bytes; | |
62a8067a | 818 | } |
f0b65f39 | 819 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 820 | |
241699cd AV |
821 | static void pipe_advance(struct iov_iter *i, size_t size) |
822 | { | |
823 | struct pipe_inode_info *pipe = i->pipe; | |
10f525a8 | 824 | int off = i->last_offset; |
8cefc107 | 825 | |
2c855de9 AV |
826 | if (!off && !size) { |
827 | pipe_discard_from(pipe, i->start_head); // discard everything | |
828 | return; | |
829 | } | |
830 | i->count -= size; | |
831 | while (1) { | |
832 | struct pipe_buffer *buf = pipe_buf(pipe, i->head); | |
241699cd | 833 | if (off) /* make it relative to the beginning of buffer */ |
10f525a8 | 834 | size += abs(off) - buf->offset; |
2c855de9 AV |
835 | if (size <= buf->len) { |
836 | buf->len = size; | |
10f525a8 | 837 | i->last_offset = last_offset(buf); |
2c855de9 | 838 | break; |
241699cd | 839 | } |
2c855de9 AV |
840 | size -= buf->len; |
841 | i->head++; | |
842 | off = 0; | |
241699cd | 843 | } |
2c855de9 | 844 | pipe_discard_from(pipe, i->head + 1); // discard everything past this one |
241699cd AV |
845 | } |
846 | ||
54c8195b PB |
847 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
848 | { | |
18fa9af7 | 849 | const struct bio_vec *bvec, *end; |
54c8195b | 850 | |
18fa9af7 AV |
851 | if (!i->count) |
852 | return; | |
853 | i->count -= size; | |
854 | ||
855 | size += i->iov_offset; | |
54c8195b | 856 | |
18fa9af7 AV |
857 | for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { |
858 | if (likely(size < bvec->bv_len)) | |
859 | break; | |
860 | size -= bvec->bv_len; | |
861 | } | |
862 | i->iov_offset = size; | |
863 | i->nr_segs -= bvec - i->bvec; | |
864 | i->bvec = bvec; | |
54c8195b PB |
865 | } |
866 | ||
185ac4d4 AV |
867 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
868 | { | |
869 | const struct iovec *iov, *end; | |
870 | ||
871 | if (!i->count) | |
872 | return; | |
873 | i->count -= size; | |
874 | ||
875 | size += i->iov_offset; // from beginning of current segment | |
876 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { | |
877 | if (likely(size < iov->iov_len)) | |
878 | break; | |
879 | size -= iov->iov_len; | |
880 | } | |
881 | i->iov_offset = size; | |
882 | i->nr_segs -= iov - i->iov; | |
883 | i->iov = iov; | |
884 | } | |
885 | ||
62a8067a AV |
886 | void iov_iter_advance(struct iov_iter *i, size_t size) |
887 | { | |
3b3fc051 AV |
888 | if (unlikely(i->count < size)) |
889 | size = i->count; | |
fcb14cb1 AV |
890 | if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { |
891 | i->iov_offset += size; | |
892 | i->count -= size; | |
893 | } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { | |
185ac4d4 AV |
894 | /* iovec and kvec have identical layouts */ |
895 | iov_iter_iovec_advance(i, size); | |
896 | } else if (iov_iter_is_bvec(i)) { | |
897 | iov_iter_bvec_advance(i, size); | |
898 | } else if (iov_iter_is_pipe(i)) { | |
241699cd | 899 | pipe_advance(i, size); |
185ac4d4 AV |
900 | } else if (iov_iter_is_discard(i)) { |
901 | i->count -= size; | |
54c8195b | 902 | } |
62a8067a AV |
903 | } |
904 | EXPORT_SYMBOL(iov_iter_advance); | |
905 | ||
27c0e374 AV |
906 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
907 | { | |
908 | if (!unroll) | |
909 | return; | |
5b47d59a AV |
910 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
911 | return; | |
27c0e374 | 912 | i->count += unroll; |
00e23707 | 913 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 914 | struct pipe_inode_info *pipe = i->pipe; |
92acdc4f AV |
915 | unsigned int head = pipe->head; |
916 | ||
917 | while (head > i->start_head) { | |
918 | struct pipe_buffer *b = pipe_buf(pipe, --head); | |
919 | if (unroll < b->len) { | |
920 | b->len -= unroll; | |
10f525a8 | 921 | i->last_offset = last_offset(b); |
92acdc4f AV |
922 | i->head = head; |
923 | return; | |
27c0e374 | 924 | } |
92acdc4f AV |
925 | unroll -= b->len; |
926 | pipe_buf_release(pipe, b); | |
927 | pipe->head--; | |
27c0e374 | 928 | } |
10f525a8 | 929 | i->last_offset = 0; |
92acdc4f | 930 | i->head = head; |
27c0e374 AV |
931 | return; |
932 | } | |
9ea9ce04 DH |
933 | if (unlikely(iov_iter_is_discard(i))) |
934 | return; | |
27c0e374 AV |
935 | if (unroll <= i->iov_offset) { |
936 | i->iov_offset -= unroll; | |
937 | return; | |
938 | } | |
939 | unroll -= i->iov_offset; | |
fcb14cb1 | 940 | if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { |
7ff50620 DH |
941 | BUG(); /* We should never go beyond the start of the specified |
942 | * range since we might then be straying into pages that | |
943 | * aren't pinned. | |
944 | */ | |
945 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
946 | const struct bio_vec *bvec = i->bvec; |
947 | while (1) { | |
948 | size_t n = (--bvec)->bv_len; | |
949 | i->nr_segs++; | |
950 | if (unroll <= n) { | |
951 | i->bvec = bvec; | |
952 | i->iov_offset = n - unroll; | |
953 | return; | |
954 | } | |
955 | unroll -= n; | |
956 | } | |
957 | } else { /* same logics for iovec and kvec */ | |
958 | const struct iovec *iov = i->iov; | |
959 | while (1) { | |
960 | size_t n = (--iov)->iov_len; | |
961 | i->nr_segs++; | |
962 | if (unroll <= n) { | |
963 | i->iov = iov; | |
964 | i->iov_offset = n - unroll; | |
965 | return; | |
966 | } | |
967 | unroll -= n; | |
968 | } | |
969 | } | |
970 | } | |
971 | EXPORT_SYMBOL(iov_iter_revert); | |
972 | ||
62a8067a AV |
973 | /* |
974 | * Return the count of just the current iov_iter segment. | |
975 | */ | |
976 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
977 | { | |
28f38db7 AV |
978 | if (i->nr_segs > 1) { |
979 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
980 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
981 | if (iov_iter_is_bvec(i)) | |
982 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
983 | } | |
984 | return i->count; | |
62a8067a AV |
985 | } |
986 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
987 | ||
aa563d7b | 988 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 989 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
990 | size_t count) |
991 | { | |
aa563d7b | 992 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
993 | *i = (struct iov_iter){ |
994 | .iter_type = ITER_KVEC, | |
995 | .data_source = direction, | |
996 | .kvec = kvec, | |
997 | .nr_segs = nr_segs, | |
998 | .iov_offset = 0, | |
999 | .count = count | |
1000 | }; | |
abb78f87 AV |
1001 | } |
1002 | EXPORT_SYMBOL(iov_iter_kvec); | |
1003 | ||
aa563d7b | 1004 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1005 | const struct bio_vec *bvec, unsigned long nr_segs, |
1006 | size_t count) | |
1007 | { | |
aa563d7b | 1008 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1009 | *i = (struct iov_iter){ |
1010 | .iter_type = ITER_BVEC, | |
1011 | .data_source = direction, | |
1012 | .bvec = bvec, | |
1013 | .nr_segs = nr_segs, | |
1014 | .iov_offset = 0, | |
1015 | .count = count | |
1016 | }; | |
05afcb77 AV |
1017 | } |
1018 | EXPORT_SYMBOL(iov_iter_bvec); | |
1019 | ||
aa563d7b | 1020 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1021 | struct pipe_inode_info *pipe, |
1022 | size_t count) | |
1023 | { | |
aa563d7b | 1024 | BUG_ON(direction != READ); |
8cefc107 | 1025 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
1026 | *i = (struct iov_iter){ |
1027 | .iter_type = ITER_PIPE, | |
1028 | .data_source = false, | |
1029 | .pipe = pipe, | |
1030 | .head = pipe->head, | |
1031 | .start_head = pipe->head, | |
10f525a8 | 1032 | .last_offset = 0, |
8cd54c1c AV |
1033 | .count = count |
1034 | }; | |
241699cd AV |
1035 | } |
1036 | EXPORT_SYMBOL(iov_iter_pipe); | |
1037 | ||
7ff50620 DH |
1038 | /** |
1039 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1040 | * @i: The iterator to initialise. | |
1041 | * @direction: The direction of the transfer. | |
1042 | * @xarray: The xarray to access. | |
1043 | * @start: The start file position. | |
1044 | * @count: The size of the I/O buffer in bytes. | |
1045 | * | |
1046 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1047 | * inode or to inject data into those pages. The pages *must* be prevented | |
1048 | * from evaporation, either by taking a ref on them or locking them by the | |
1049 | * caller. | |
1050 | */ | |
1051 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1052 | struct xarray *xarray, loff_t start, size_t count) | |
1053 | { | |
1054 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
1055 | *i = (struct iov_iter) { |
1056 | .iter_type = ITER_XARRAY, | |
1057 | .data_source = direction, | |
1058 | .xarray = xarray, | |
1059 | .xarray_start = start, | |
1060 | .count = count, | |
1061 | .iov_offset = 0 | |
1062 | }; | |
7ff50620 DH |
1063 | } |
1064 | EXPORT_SYMBOL(iov_iter_xarray); | |
1065 | ||
9ea9ce04 DH |
1066 | /** |
1067 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1068 | * @i: The iterator to initialise. | |
1069 | * @direction: The direction of the transfer. | |
1070 | * @count: The size of the I/O buffer in bytes. | |
1071 | * | |
1072 | * Set up an I/O iterator that just discards everything that's written to it. | |
1073 | * It's only available as a READ iterator. | |
1074 | */ | |
1075 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1076 | { | |
1077 | BUG_ON(direction != READ); | |
8cd54c1c AV |
1078 | *i = (struct iov_iter){ |
1079 | .iter_type = ITER_DISCARD, | |
1080 | .data_source = false, | |
1081 | .count = count, | |
1082 | .iov_offset = 0 | |
1083 | }; | |
9ea9ce04 DH |
1084 | } |
1085 | EXPORT_SYMBOL(iov_iter_discard); | |
1086 | ||
cfa320f7 KB |
1087 | static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, |
1088 | unsigned len_mask) | |
1089 | { | |
1090 | size_t size = i->count; | |
1091 | size_t skip = i->iov_offset; | |
1092 | unsigned k; | |
1093 | ||
1094 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1095 | size_t len = i->iov[k].iov_len - skip; | |
1096 | ||
1097 | if (len > size) | |
1098 | len = size; | |
1099 | if (len & len_mask) | |
1100 | return false; | |
1101 | if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask) | |
1102 | return false; | |
1103 | ||
1104 | size -= len; | |
1105 | if (!size) | |
1106 | break; | |
1107 | } | |
1108 | return true; | |
1109 | } | |
1110 | ||
1111 | static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, | |
1112 | unsigned len_mask) | |
1113 | { | |
1114 | size_t size = i->count; | |
1115 | unsigned skip = i->iov_offset; | |
1116 | unsigned k; | |
1117 | ||
1118 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1119 | size_t len = i->bvec[k].bv_len - skip; | |
1120 | ||
1121 | if (len > size) | |
1122 | len = size; | |
1123 | if (len & len_mask) | |
1124 | return false; | |
1125 | if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask) | |
1126 | return false; | |
1127 | ||
1128 | size -= len; | |
1129 | if (!size) | |
1130 | break; | |
1131 | } | |
1132 | return true; | |
1133 | } | |
1134 | ||
1135 | /** | |
1136 | * iov_iter_is_aligned() - Check if the addresses and lengths of each segments | |
1137 | * are aligned to the parameters. | |
1138 | * | |
1139 | * @i: &struct iov_iter to restore | |
1140 | * @addr_mask: bit mask to check against the iov element's addresses | |
1141 | * @len_mask: bit mask to check against the iov element's lengths | |
1142 | * | |
1143 | * Return: false if any addresses or lengths intersect with the provided masks | |
1144 | */ | |
1145 | bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, | |
1146 | unsigned len_mask) | |
1147 | { | |
fcb14cb1 AV |
1148 | if (likely(iter_is_ubuf(i))) { |
1149 | if (i->count & len_mask) | |
1150 | return false; | |
1151 | if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) | |
1152 | return false; | |
1153 | return true; | |
1154 | } | |
1155 | ||
cfa320f7 KB |
1156 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
1157 | return iov_iter_aligned_iovec(i, addr_mask, len_mask); | |
1158 | ||
1159 | if (iov_iter_is_bvec(i)) | |
1160 | return iov_iter_aligned_bvec(i, addr_mask, len_mask); | |
1161 | ||
1162 | if (iov_iter_is_pipe(i)) { | |
cfa320f7 KB |
1163 | size_t size = i->count; |
1164 | ||
1165 | if (size & len_mask) | |
1166 | return false; | |
10f525a8 AV |
1167 | if (size && i->last_offset > 0) { |
1168 | if (i->last_offset & addr_mask) | |
cfa320f7 KB |
1169 | return false; |
1170 | } | |
1171 | ||
1172 | return true; | |
1173 | } | |
1174 | ||
1175 | if (iov_iter_is_xarray(i)) { | |
1176 | if (i->count & len_mask) | |
1177 | return false; | |
1178 | if ((i->xarray_start + i->iov_offset) & addr_mask) | |
1179 | return false; | |
1180 | } | |
1181 | ||
1182 | return true; | |
1183 | } | |
1184 | EXPORT_SYMBOL_GPL(iov_iter_is_aligned); | |
1185 | ||
9221d2e3 | 1186 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1187 | { |
04a31165 AV |
1188 | unsigned long res = 0; |
1189 | size_t size = i->count; | |
9221d2e3 AV |
1190 | size_t skip = i->iov_offset; |
1191 | unsigned k; | |
1192 | ||
1193 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1194 | size_t len = i->iov[k].iov_len - skip; | |
1195 | if (len) { | |
1196 | res |= (unsigned long)i->iov[k].iov_base + skip; | |
1197 | if (len > size) | |
1198 | len = size; | |
1199 | res |= len; | |
1200 | size -= len; | |
1201 | if (!size) | |
1202 | break; | |
1203 | } | |
1204 | } | |
1205 | return res; | |
1206 | } | |
04a31165 | 1207 | |
9221d2e3 AV |
1208 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
1209 | { | |
1210 | unsigned res = 0; | |
1211 | size_t size = i->count; | |
1212 | unsigned skip = i->iov_offset; | |
1213 | unsigned k; | |
1214 | ||
1215 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1216 | size_t len = i->bvec[k].bv_len - skip; | |
1217 | res |= (unsigned long)i->bvec[k].bv_offset + skip; | |
1218 | if (len > size) | |
1219 | len = size; | |
1220 | res |= len; | |
1221 | size -= len; | |
1222 | if (!size) | |
1223 | break; | |
1224 | } | |
1225 | return res; | |
1226 | } | |
1227 | ||
1228 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
1229 | { | |
fcb14cb1 AV |
1230 | if (likely(iter_is_ubuf(i))) { |
1231 | size_t size = i->count; | |
1232 | if (size) | |
1233 | return ((unsigned long)i->ubuf + i->iov_offset) | size; | |
1234 | return 0; | |
1235 | } | |
1236 | ||
9221d2e3 AV |
1237 | /* iovec and kvec have identical layouts */ |
1238 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1239 | return iov_iter_alignment_iovec(i); | |
1240 | ||
1241 | if (iov_iter_is_bvec(i)) | |
1242 | return iov_iter_alignment_bvec(i); | |
1243 | ||
1244 | if (iov_iter_is_pipe(i)) { | |
9221d2e3 | 1245 | size_t size = i->count; |
e0ff126e | 1246 | |
10f525a8 AV |
1247 | if (size && i->last_offset > 0) |
1248 | return size | i->last_offset; | |
241699cd AV |
1249 | return size; |
1250 | } | |
9221d2e3 AV |
1251 | |
1252 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1253 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1254 | |
1255 | return 0; | |
62a8067a AV |
1256 | } |
1257 | EXPORT_SYMBOL(iov_iter_alignment); | |
1258 | ||
357f435d AV |
1259 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1260 | { | |
33844e66 | 1261 | unsigned long res = 0; |
610c7a71 | 1262 | unsigned long v = 0; |
357f435d | 1263 | size_t size = i->count; |
610c7a71 | 1264 | unsigned k; |
357f435d | 1265 | |
fcb14cb1 AV |
1266 | if (iter_is_ubuf(i)) |
1267 | return 0; | |
1268 | ||
610c7a71 | 1269 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1270 | return ~0U; |
241699cd | 1271 | |
610c7a71 AV |
1272 | for (k = 0; k < i->nr_segs; k++) { |
1273 | if (i->iov[k].iov_len) { | |
1274 | unsigned long base = (unsigned long)i->iov[k].iov_base; | |
1275 | if (v) // if not the first one | |
1276 | res |= base | v; // this start | previous end | |
1277 | v = base + i->iov[k].iov_len; | |
1278 | if (size <= i->iov[k].iov_len) | |
1279 | break; | |
1280 | size -= i->iov[k].iov_len; | |
1281 | } | |
1282 | } | |
33844e66 | 1283 | return res; |
357f435d AV |
1284 | } |
1285 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1286 | ||
acbdeb83 AV |
1287 | static struct page **get_pages_array(size_t n) |
1288 | { | |
1289 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); | |
1290 | } | |
1291 | ||
e76b6312 | 1292 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1293 | size_t maxsize, |
1294 | struct page **pages, | |
e3b42964 | 1295 | size_t off) |
241699cd AV |
1296 | { |
1297 | struct pipe_inode_info *pipe = i->pipe; | |
e3b42964 | 1298 | ssize_t left = maxsize; |
241699cd | 1299 | |
e3b42964 | 1300 | if (off) { |
ca591967 | 1301 | struct pipe_buffer *buf = pipe_buf(pipe, pipe->head - 1); |
241699cd | 1302 | |
e3b42964 AV |
1303 | get_page(*pages++ = buf->page); |
1304 | left -= PAGE_SIZE - off; | |
1305 | if (left <= 0) { | |
1306 | buf->len += maxsize; | |
1307 | return maxsize; | |
1308 | } | |
1309 | buf->len = PAGE_SIZE; | |
1310 | } | |
1311 | while (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { | |
1312 | struct page *page = push_anon(pipe, | |
1313 | min_t(ssize_t, left, PAGE_SIZE)); | |
1314 | if (!page) | |
1315 | break; | |
1316 | get_page(*pages++ = page); | |
1317 | left -= PAGE_SIZE; | |
1318 | if (left <= 0) | |
1319 | return maxsize; | |
1320 | } | |
1321 | return maxsize - left ? : -EFAULT; | |
241699cd AV |
1322 | } |
1323 | ||
1324 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
acbdeb83 | 1325 | struct page ***pages, size_t maxsize, unsigned maxpages, |
241699cd AV |
1326 | size_t *start) |
1327 | { | |
12d426ab | 1328 | unsigned int npages, off; |
acbdeb83 | 1329 | struct page **p; |
241699cd | 1330 | size_t capacity; |
241699cd AV |
1331 | |
1332 | if (!sanity(i)) | |
1333 | return -EFAULT; | |
1334 | ||
12d426ab AV |
1335 | *start = off = pipe_npages(i, &npages); |
1336 | capacity = min(npages, maxpages) * PAGE_SIZE - off; | |
acbdeb83 AV |
1337 | maxsize = min(maxsize, capacity); |
1338 | p = *pages; | |
1339 | if (!p) { | |
1340 | *pages = p = get_pages_array(DIV_ROUND_UP(maxsize + off, PAGE_SIZE)); | |
1341 | if (!p) | |
1342 | return -ENOMEM; | |
1343 | } | |
241699cd | 1344 | |
acbdeb83 | 1345 | return __pipe_get_pages(i, maxsize, p, off); |
241699cd AV |
1346 | } |
1347 | ||
7ff50620 DH |
1348 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1349 | pgoff_t index, unsigned int nr_pages) | |
1350 | { | |
1351 | XA_STATE(xas, xa, index); | |
1352 | struct page *page; | |
1353 | unsigned int ret = 0; | |
1354 | ||
1355 | rcu_read_lock(); | |
1356 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1357 | if (xas_retry(&xas, page)) | |
1358 | continue; | |
1359 | ||
1360 | /* Has the page moved or been split? */ | |
1361 | if (unlikely(page != xas_reload(&xas))) { | |
1362 | xas_reset(&xas); | |
1363 | continue; | |
1364 | } | |
1365 | ||
1366 | pages[ret] = find_subpage(page, xas.xa_index); | |
1367 | get_page(pages[ret]); | |
1368 | if (++ret == nr_pages) | |
1369 | break; | |
1370 | } | |
1371 | rcu_read_unlock(); | |
1372 | return ret; | |
1373 | } | |
1374 | ||
1375 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
68fe506f | 1376 | struct page ***pages, size_t maxsize, |
7ff50620 DH |
1377 | unsigned maxpages, size_t *_start_offset) |
1378 | { | |
1379 | unsigned nr, offset; | |
1380 | pgoff_t index, count; | |
6c776766 | 1381 | size_t size = maxsize; |
7ff50620 DH |
1382 | loff_t pos; |
1383 | ||
7ff50620 DH |
1384 | pos = i->xarray_start + i->iov_offset; |
1385 | index = pos >> PAGE_SHIFT; | |
1386 | offset = pos & ~PAGE_MASK; | |
1387 | *_start_offset = offset; | |
1388 | ||
0aa4fc32 | 1389 | count = DIV_ROUND_UP(size + offset, PAGE_SIZE); |
7ff50620 DH |
1390 | if (count > maxpages) |
1391 | count = maxpages; | |
1392 | ||
68fe506f AV |
1393 | if (!*pages) { |
1394 | *pages = get_pages_array(count); | |
1395 | if (!*pages) | |
1396 | return -ENOMEM; | |
1397 | } | |
1398 | ||
1399 | nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); | |
7ff50620 DH |
1400 | if (nr == 0) |
1401 | return 0; | |
1402 | ||
1c27f1fc | 1403 | return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); |
7ff50620 DH |
1404 | } |
1405 | ||
fcb14cb1 | 1406 | /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ |
dd45ab9d | 1407 | static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) |
3d671ca6 AV |
1408 | { |
1409 | size_t skip; | |
1410 | long k; | |
1411 | ||
fcb14cb1 AV |
1412 | if (iter_is_ubuf(i)) |
1413 | return (unsigned long)i->ubuf + i->iov_offset; | |
1414 | ||
3d671ca6 | 1415 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { |
3d671ca6 AV |
1416 | size_t len = i->iov[k].iov_len - skip; |
1417 | ||
1418 | if (unlikely(!len)) | |
1419 | continue; | |
59dbd7d0 AV |
1420 | if (*size > len) |
1421 | *size = len; | |
dd45ab9d | 1422 | return (unsigned long)i->iov[k].iov_base + skip; |
3d671ca6 AV |
1423 | } |
1424 | BUG(); // if it had been empty, we wouldn't get called | |
1425 | } | |
1426 | ||
1427 | /* must be done on non-empty ITER_BVEC one */ | |
1428 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
59dbd7d0 | 1429 | size_t *size, size_t *start) |
3d671ca6 AV |
1430 | { |
1431 | struct page *page; | |
1432 | size_t skip = i->iov_offset, len; | |
1433 | ||
1434 | len = i->bvec->bv_len - skip; | |
59dbd7d0 AV |
1435 | if (*size > len) |
1436 | *size = len; | |
3d671ca6 AV |
1437 | skip += i->bvec->bv_offset; |
1438 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
dda8e5d1 | 1439 | *start = skip % PAGE_SIZE; |
3d671ca6 AV |
1440 | return page; |
1441 | } | |
1442 | ||
451c0ba9 AV |
1443 | static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, |
1444 | struct page ***pages, size_t maxsize, | |
1445 | unsigned int maxpages, size_t *start) | |
62a8067a | 1446 | { |
3d671ca6 AV |
1447 | int n, res; |
1448 | ||
e5393fae AV |
1449 | if (maxsize > i->count) |
1450 | maxsize = i->count; | |
451c0ba9 | 1451 | if (!maxsize) |
3d671ca6 | 1452 | return 0; |
7392ed17 AV |
1453 | if (maxsize > MAX_RW_COUNT) |
1454 | maxsize = MAX_RW_COUNT; | |
e5393fae | 1455 | |
fcb14cb1 | 1456 | if (likely(user_backed_iter(i))) { |
3337ab08 | 1457 | unsigned int gup_flags = 0; |
3d671ca6 | 1458 | unsigned long addr; |
e5393fae | 1459 | |
3337ab08 AG |
1460 | if (iov_iter_rw(i) != WRITE) |
1461 | gup_flags |= FOLL_WRITE; | |
1462 | if (i->nofault) | |
1463 | gup_flags |= FOLL_NOFAULT; | |
1464 | ||
dd45ab9d AV |
1465 | addr = first_iovec_segment(i, &maxsize); |
1466 | *start = addr % PAGE_SIZE; | |
1467 | addr &= PAGE_MASK; | |
59dbd7d0 | 1468 | n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); |
dda8e5d1 AV |
1469 | if (n > maxpages) |
1470 | n = maxpages; | |
451c0ba9 AV |
1471 | if (!*pages) { |
1472 | *pages = get_pages_array(n); | |
1473 | if (!*pages) | |
1474 | return -ENOMEM; | |
1475 | } | |
1476 | res = get_user_pages_fast(addr, n, gup_flags, *pages); | |
814a6674 | 1477 | if (unlikely(res <= 0)) |
e5393fae | 1478 | return res; |
59dbd7d0 | 1479 | return min_t(size_t, maxsize, res * PAGE_SIZE - *start); |
3d671ca6 AV |
1480 | } |
1481 | if (iov_iter_is_bvec(i)) { | |
451c0ba9 | 1482 | struct page **p; |
3d671ca6 AV |
1483 | struct page *page; |
1484 | ||
59dbd7d0 AV |
1485 | page = first_bvec_segment(i, &maxsize, start); |
1486 | n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
dda8e5d1 AV |
1487 | if (n > maxpages) |
1488 | n = maxpages; | |
451c0ba9 AV |
1489 | p = *pages; |
1490 | if (!p) { | |
1491 | *pages = p = get_pages_array(n); | |
1492 | if (!p) | |
1493 | return -ENOMEM; | |
1494 | } | |
dda8e5d1 | 1495 | for (int k = 0; k < n; k++) |
451c0ba9 | 1496 | get_page(*p++ = page++); |
59dbd7d0 | 1497 | return min_t(size_t, maxsize, n * PAGE_SIZE - *start); |
3d671ca6 AV |
1498 | } |
1499 | if (iov_iter_is_pipe(i)) | |
451c0ba9 | 1500 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
3d671ca6 | 1501 | if (iov_iter_is_xarray(i)) |
451c0ba9 | 1502 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); |
3d671ca6 | 1503 | return -EFAULT; |
62a8067a | 1504 | } |
62a8067a | 1505 | |
451c0ba9 AV |
1506 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
1507 | struct page **pages, size_t maxsize, unsigned maxpages, | |
62a8067a AV |
1508 | size_t *start) |
1509 | { | |
451c0ba9 | 1510 | if (!maxpages) |
3d671ca6 | 1511 | return 0; |
451c0ba9 | 1512 | BUG_ON(!pages); |
3d671ca6 | 1513 | |
451c0ba9 | 1514 | return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); |
62a8067a | 1515 | } |
451c0ba9 | 1516 | EXPORT_SYMBOL(iov_iter_get_pages); |
91329559 AV |
1517 | |
1518 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, | |
1519 | struct page ***pages, size_t maxsize, | |
1520 | size_t *start) | |
1521 | { | |
1522 | ssize_t len; | |
1523 | ||
1524 | *pages = NULL; | |
1525 | ||
451c0ba9 | 1526 | len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); |
91329559 AV |
1527 | if (len <= 0) { |
1528 | kvfree(*pages); | |
1529 | *pages = NULL; | |
1530 | } | |
1531 | return len; | |
1532 | } | |
62a8067a AV |
1533 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); |
1534 | ||
a604ec7e AV |
1535 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1536 | struct iov_iter *i) | |
1537 | { | |
a604ec7e | 1538 | __wsum sum, next; |
a604ec7e | 1539 | sum = *csum; |
9ea9ce04 | 1540 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1541 | WARN_ON(1); |
1542 | return 0; | |
1543 | } | |
7baa5099 AV |
1544 | iterate_and_advance(i, bytes, base, len, off, ({ |
1545 | next = csum_and_copy_from_user(base, addr + off, len); | |
2495bdcc | 1546 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1547 | next ? 0 : len; |
a604ec7e | 1548 | }), ({ |
7baa5099 | 1549 | sum = csum_and_memcpy(addr + off, base, len, sum, off); |
a604ec7e AV |
1550 | }) |
1551 | ) | |
1552 | *csum = sum; | |
1553 | return bytes; | |
1554 | } | |
1555 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1556 | ||
52cbd23a | 1557 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1558 | struct iov_iter *i) |
1559 | { | |
52cbd23a | 1560 | struct csum_state *csstate = _csstate; |
a604ec7e | 1561 | __wsum sum, next; |
78e1f386 | 1562 | |
78e1f386 | 1563 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1564 | WARN_ON(1); /* for now */ |
1565 | return 0; | |
1566 | } | |
6852df12 AV |
1567 | |
1568 | sum = csum_shift(csstate->csum, csstate->off); | |
1569 | if (unlikely(iov_iter_is_pipe(i))) | |
1570 | bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); | |
1571 | else iterate_and_advance(i, bytes, base, len, off, ({ | |
7baa5099 | 1572 | next = csum_and_copy_to_user(addr + off, base, len); |
2495bdcc | 1573 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1574 | next ? 0 : len; |
a604ec7e | 1575 | }), ({ |
7baa5099 | 1576 | sum = csum_and_memcpy(base, addr + off, len, sum, off); |
a604ec7e AV |
1577 | }) |
1578 | ) | |
594e450b AV |
1579 | csstate->csum = csum_shift(sum, csstate->off); |
1580 | csstate->off += bytes; | |
a604ec7e AV |
1581 | return bytes; |
1582 | } | |
1583 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1584 | ||
d05f4435 SG |
1585 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1586 | struct iov_iter *i) | |
1587 | { | |
7999096f | 1588 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1589 | struct ahash_request *hash = hashp; |
1590 | struct scatterlist sg; | |
1591 | size_t copied; | |
1592 | ||
1593 | copied = copy_to_iter(addr, bytes, i); | |
1594 | sg_init_one(&sg, addr, copied); | |
1595 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1596 | crypto_ahash_update(hash); | |
1597 | return copied; | |
27fad74a Y |
1598 | #else |
1599 | return 0; | |
1600 | #endif | |
d05f4435 SG |
1601 | } |
1602 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1603 | ||
66531c65 | 1604 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1605 | { |
66531c65 AV |
1606 | size_t skip = i->iov_offset, size = i->count; |
1607 | const struct iovec *p; | |
e0f2dc40 AV |
1608 | int npages = 0; |
1609 | ||
66531c65 AV |
1610 | for (p = i->iov; size; skip = 0, p++) { |
1611 | unsigned offs = offset_in_page(p->iov_base + skip); | |
1612 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1613 | |
66531c65 AV |
1614 | if (len) { |
1615 | size -= len; | |
1616 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1617 | if (unlikely(npages > maxpages)) | |
1618 | return maxpages; | |
1619 | } | |
1620 | } | |
1621 | return npages; | |
1622 | } | |
1623 | ||
1624 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1625 | { | |
1626 | size_t skip = i->iov_offset, size = i->count; | |
1627 | const struct bio_vec *p; | |
1628 | int npages = 0; | |
1629 | ||
1630 | for (p = i->bvec; size; skip = 0, p++) { | |
1631 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1632 | size_t len = min(p->bv_len - skip, size); | |
1633 | ||
1634 | size -= len; | |
1635 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1636 | if (unlikely(npages > maxpages)) | |
1637 | return maxpages; | |
1638 | } | |
1639 | return npages; | |
1640 | } | |
1641 | ||
1642 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1643 | { | |
1644 | if (unlikely(!i->count)) | |
1645 | return 0; | |
fcb14cb1 AV |
1646 | if (likely(iter_is_ubuf(i))) { |
1647 | unsigned offs = offset_in_page(i->ubuf + i->iov_offset); | |
1648 | int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); | |
1649 | return min(npages, maxpages); | |
1650 | } | |
66531c65 AV |
1651 | /* iovec and kvec have identical layouts */ |
1652 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1653 | return iov_npages(i, maxpages); | |
1654 | if (iov_iter_is_bvec(i)) | |
1655 | return bvec_npages(i, maxpages); | |
1656 | if (iov_iter_is_pipe(i)) { | |
66531c65 | 1657 | int npages; |
241699cd AV |
1658 | |
1659 | if (!sanity(i)) | |
1660 | return 0; | |
1661 | ||
12d426ab | 1662 | pipe_npages(i, &npages); |
66531c65 AV |
1663 | return min(npages, maxpages); |
1664 | } | |
1665 | if (iov_iter_is_xarray(i)) { | |
e4f8df86 AV |
1666 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1667 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1668 | return min(npages, maxpages); |
1669 | } | |
1670 | return 0; | |
62a8067a | 1671 | } |
f67da30c | 1672 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1673 | |
1674 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1675 | { | |
1676 | *new = *old; | |
00e23707 | 1677 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1678 | WARN_ON(1); |
1679 | return NULL; | |
1680 | } | |
00e23707 | 1681 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1682 | return new->bvec = kmemdup(new->bvec, |
1683 | new->nr_segs * sizeof(struct bio_vec), | |
1684 | flags); | |
fcb14cb1 | 1685 | else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) |
4b8164b9 AV |
1686 | /* iovec and kvec have identical layout */ |
1687 | return new->iov = kmemdup(new->iov, | |
1688 | new->nr_segs * sizeof(struct iovec), | |
1689 | flags); | |
fcb14cb1 | 1690 | return NULL; |
4b8164b9 AV |
1691 | } |
1692 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1693 | |
bfdc5970 CH |
1694 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1695 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1696 | { | |
1697 | const struct compat_iovec __user *uiov = | |
1698 | (const struct compat_iovec __user *)uvec; | |
1699 | int ret = -EFAULT, i; | |
1700 | ||
a959a978 | 1701 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1702 | return -EFAULT; |
1703 | ||
1704 | for (i = 0; i < nr_segs; i++) { | |
1705 | compat_uptr_t buf; | |
1706 | compat_ssize_t len; | |
1707 | ||
1708 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1709 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1710 | ||
1711 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1712 | if (len < 0) { | |
1713 | ret = -EINVAL; | |
1714 | goto uaccess_end; | |
1715 | } | |
1716 | iov[i].iov_base = compat_ptr(buf); | |
1717 | iov[i].iov_len = len; | |
1718 | } | |
1719 | ||
1720 | ret = 0; | |
1721 | uaccess_end: | |
1722 | user_access_end(); | |
1723 | return ret; | |
1724 | } | |
1725 | ||
1726 | static int copy_iovec_from_user(struct iovec *iov, | |
1727 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1728 | { |
1729 | unsigned long seg; | |
fb041b59 | 1730 | |
bfdc5970 CH |
1731 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1732 | return -EFAULT; | |
1733 | for (seg = 0; seg < nr_segs; seg++) { | |
1734 | if ((ssize_t)iov[seg].iov_len < 0) | |
1735 | return -EINVAL; | |
fb041b59 DL |
1736 | } |
1737 | ||
bfdc5970 CH |
1738 | return 0; |
1739 | } | |
1740 | ||
1741 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1742 | unsigned long nr_segs, unsigned long fast_segs, | |
1743 | struct iovec *fast_iov, bool compat) | |
1744 | { | |
1745 | struct iovec *iov = fast_iov; | |
1746 | int ret; | |
1747 | ||
fb041b59 | 1748 | /* |
bfdc5970 CH |
1749 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1750 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1751 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1752 | */ |
bfdc5970 CH |
1753 | if (nr_segs == 0) |
1754 | return iov; | |
1755 | if (nr_segs > UIO_MAXIOV) | |
1756 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1757 | if (nr_segs > fast_segs) { |
1758 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1759 | if (!iov) |
1760 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1761 | } |
bfdc5970 CH |
1762 | |
1763 | if (compat) | |
1764 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1765 | else | |
1766 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1767 | if (ret) { | |
1768 | if (iov != fast_iov) | |
1769 | kfree(iov); | |
1770 | return ERR_PTR(ret); | |
1771 | } | |
1772 | ||
1773 | return iov; | |
1774 | } | |
1775 | ||
1776 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
1777 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
1778 | struct iov_iter *i, bool compat) | |
1779 | { | |
1780 | ssize_t total_len = 0; | |
1781 | unsigned long seg; | |
1782 | struct iovec *iov; | |
1783 | ||
1784 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
1785 | if (IS_ERR(iov)) { | |
1786 | *iovp = NULL; | |
1787 | return PTR_ERR(iov); | |
fb041b59 DL |
1788 | } |
1789 | ||
1790 | /* | |
bfdc5970 CH |
1791 | * According to the Single Unix Specification we should return EINVAL if |
1792 | * an element length is < 0 when cast to ssize_t or if the total length | |
1793 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
1794 | * |
1795 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
1796 | * overflow case. | |
1797 | */ | |
fb041b59 | 1798 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
1799 | ssize_t len = (ssize_t)iov[seg].iov_len; |
1800 | ||
bfdc5970 CH |
1801 | if (!access_ok(iov[seg].iov_base, len)) { |
1802 | if (iov != *iovp) | |
1803 | kfree(iov); | |
1804 | *iovp = NULL; | |
1805 | return -EFAULT; | |
fb041b59 | 1806 | } |
bfdc5970 CH |
1807 | |
1808 | if (len > MAX_RW_COUNT - total_len) { | |
1809 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
1810 | iov[seg].iov_len = len; |
1811 | } | |
bfdc5970 | 1812 | total_len += len; |
fb041b59 | 1813 | } |
bfdc5970 CH |
1814 | |
1815 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
1816 | if (iov == *iovp) | |
1817 | *iovp = NULL; | |
1818 | else | |
1819 | *iovp = iov; | |
1820 | return total_len; | |
fb041b59 DL |
1821 | } |
1822 | ||
ffecee4f VN |
1823 | /** |
1824 | * import_iovec() - Copy an array of &struct iovec from userspace | |
1825 | * into the kernel, check that it is valid, and initialize a new | |
1826 | * &struct iov_iter iterator to access it. | |
1827 | * | |
1828 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 1829 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
1830 | * @nr_segs: Number of elements in userspace array. |
1831 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 1832 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
1833 | * on-stack) kernel array. |
1834 | * @i: Pointer to iterator that will be initialized on success. | |
1835 | * | |
1836 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
1837 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
1838 | * array will be allocated and the result placed in *@iov. This means that | |
1839 | * the caller may call kfree() on *@iov regardless of whether the small | |
1840 | * on-stack array was used or not (and regardless of whether this function | |
1841 | * returns an error or not). | |
1842 | * | |
87e5e6da | 1843 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 1844 | */ |
bfdc5970 | 1845 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 1846 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 1847 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 1848 | { |
89cd35c5 CH |
1849 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
1850 | in_compat_syscall()); | |
bc917be8 AV |
1851 | } |
1852 | EXPORT_SYMBOL(import_iovec); | |
1853 | ||
bc917be8 AV |
1854 | int import_single_range(int rw, void __user *buf, size_t len, |
1855 | struct iovec *iov, struct iov_iter *i) | |
1856 | { | |
1857 | if (len > MAX_RW_COUNT) | |
1858 | len = MAX_RW_COUNT; | |
96d4f267 | 1859 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
1860 | return -EFAULT; |
1861 | ||
1862 | iov->iov_base = buf; | |
1863 | iov->iov_len = len; | |
1864 | iov_iter_init(i, rw, iov, 1, len); | |
1865 | return 0; | |
1866 | } | |
e1267585 | 1867 | EXPORT_SYMBOL(import_single_range); |
8fb0f47a JA |
1868 | |
1869 | /** | |
1870 | * iov_iter_restore() - Restore a &struct iov_iter to the same state as when | |
1871 | * iov_iter_save_state() was called. | |
1872 | * | |
1873 | * @i: &struct iov_iter to restore | |
1874 | * @state: state to restore from | |
1875 | * | |
1876 | * Used after iov_iter_save_state() to bring restore @i, if operations may | |
1877 | * have advanced it. | |
1878 | * | |
1879 | * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC | |
1880 | */ | |
1881 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) | |
1882 | { | |
1883 | if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && | |
fcb14cb1 | 1884 | !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) |
8fb0f47a JA |
1885 | return; |
1886 | i->iov_offset = state->iov_offset; | |
1887 | i->count = state->count; | |
fcb14cb1 AV |
1888 | if (iter_is_ubuf(i)) |
1889 | return; | |
8fb0f47a JA |
1890 | /* |
1891 | * For the *vec iters, nr_segs + iov is constant - if we increment | |
1892 | * the vec, then we also decrement the nr_segs count. Hence we don't | |
1893 | * need to track both of these, just one is enough and we can deduct | |
1894 | * the other from that. ITER_KVEC and ITER_IOVEC are the same struct | |
1895 | * size, so we can just increment the iov pointer as they are unionzed. | |
1896 | * ITER_BVEC _may_ be the same size on some archs, but on others it is | |
1897 | * not. Be safe and handle it separately. | |
1898 | */ | |
1899 | BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); | |
1900 | if (iov_iter_is_bvec(i)) | |
1901 | i->bvec -= state->nr_segs - i->nr_segs; | |
1902 | else | |
1903 | i->iov -= state->nr_segs - i->nr_segs; | |
1904 | i->nr_segs = state->nr_segs; | |
1905 | } |