Commit | Line | Data |
---|---|---|
5274f052 JA |
1 | /* |
2 | * "splice": joining two ropes together by interweaving their strands. | |
3 | * | |
4 | * This is the "extended pipe" functionality, where a pipe is used as | |
5 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel | |
6 | * buffer that you can use to transfer data from one end to the other. | |
7 | * | |
8 | * The traditional unix read/write is extended with a "splice()" operation | |
9 | * that transfers data buffers to or from a pipe buffer. | |
10 | * | |
11 | * Named by Larry McVoy, original implementation from Linus, extended by | |
c2058e06 JA |
12 | * Jens to support splicing to files, network, direct splicing, etc and |
13 | * fixing lots of bugs. | |
5274f052 | 14 | * |
c2058e06 JA |
15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de> |
16 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> | |
17 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> | |
5274f052 JA |
18 | * |
19 | */ | |
20 | #include <linux/fs.h> | |
21 | #include <linux/file.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/pipe_fs_i.h> | |
24 | #include <linux/mm_inline.h> | |
5abc97aa | 25 | #include <linux/swap.h> |
4f6f0bd2 JA |
26 | #include <linux/writeback.h> |
27 | #include <linux/buffer_head.h> | |
a0f06780 | 28 | #include <linux/module.h> |
4f6f0bd2 | 29 | #include <linux/syscalls.h> |
912d35f8 | 30 | #include <linux/uio.h> |
5274f052 | 31 | |
912d35f8 JA |
32 | struct partial_page { |
33 | unsigned int offset; | |
34 | unsigned int len; | |
35 | }; | |
36 | ||
37 | /* | |
00522fb4 | 38 | * Passed to splice_to_pipe |
912d35f8 JA |
39 | */ |
40 | struct splice_pipe_desc { | |
41 | struct page **pages; /* page map */ | |
42 | struct partial_page *partial; /* pages[] may not be contig */ | |
43 | int nr_pages; /* number of pages in map */ | |
44 | unsigned int flags; /* splice flags */ | |
45 | struct pipe_buf_operations *ops;/* ops associated with output pipe */ | |
46 | }; | |
47 | ||
83f9135b JA |
48 | /* |
49 | * Attempt to steal a page from a pipe buffer. This should perhaps go into | |
50 | * a vm helper function, it's already simplified quite a bit by the | |
51 | * addition of remove_mapping(). If success is returned, the caller may | |
52 | * attempt to reuse this page for another destination. | |
53 | */ | |
5abc97aa JA |
54 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, |
55 | struct pipe_buffer *buf) | |
56 | { | |
57 | struct page *page = buf->page; | |
4f6f0bd2 | 58 | struct address_space *mapping = page_mapping(page); |
5abc97aa | 59 | |
9e0267c2 JA |
60 | lock_page(page); |
61 | ||
5abc97aa JA |
62 | WARN_ON(!PageUptodate(page)); |
63 | ||
ad8d6f0a JA |
64 | /* |
65 | * At least for ext2 with nobh option, we need to wait on writeback | |
66 | * completing on this page, since we'll remove it from the pagecache. | |
67 | * Otherwise truncate wont wait on the page, allowing the disk | |
68 | * blocks to be reused by someone else before we actually wrote our | |
69 | * data to them. fs corruption ensues. | |
70 | */ | |
71 | wait_on_page_writeback(page); | |
72 | ||
4f6f0bd2 JA |
73 | if (PagePrivate(page)) |
74 | try_to_release_page(page, mapping_gfp_mask(mapping)); | |
75 | ||
9e0267c2 JA |
76 | if (!remove_mapping(mapping, page)) { |
77 | unlock_page(page); | |
5abc97aa | 78 | return 1; |
9e0267c2 | 79 | } |
5abc97aa | 80 | |
3e7ee3e7 | 81 | buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; |
5abc97aa JA |
82 | return 0; |
83 | } | |
84 | ||
5274f052 JA |
85 | static void page_cache_pipe_buf_release(struct pipe_inode_info *info, |
86 | struct pipe_buffer *buf) | |
87 | { | |
88 | page_cache_release(buf->page); | |
89 | buf->page = NULL; | |
3e7ee3e7 | 90 | buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); |
5274f052 JA |
91 | } |
92 | ||
93 | static void *page_cache_pipe_buf_map(struct file *file, | |
94 | struct pipe_inode_info *info, | |
95 | struct pipe_buffer *buf) | |
96 | { | |
97 | struct page *page = buf->page; | |
49d0b21b | 98 | int err; |
5274f052 JA |
99 | |
100 | if (!PageUptodate(page)) { | |
49d0b21b JA |
101 | lock_page(page); |
102 | ||
103 | /* | |
104 | * Page got truncated/unhashed. This will cause a 0-byte | |
73d62d83 | 105 | * splice, if this is the first page. |
49d0b21b JA |
106 | */ |
107 | if (!page->mapping) { | |
108 | err = -ENODATA; | |
109 | goto error; | |
110 | } | |
5274f052 | 111 | |
49d0b21b | 112 | /* |
73d62d83 | 113 | * Uh oh, read-error from disk. |
49d0b21b JA |
114 | */ |
115 | if (!PageUptodate(page)) { | |
116 | err = -EIO; | |
117 | goto error; | |
118 | } | |
119 | ||
120 | /* | |
73d62d83 | 121 | * Page is ok afterall, fall through to mapping. |
49d0b21b | 122 | */ |
5274f052 | 123 | unlock_page(page); |
5274f052 JA |
124 | } |
125 | ||
49d0b21b JA |
126 | return kmap(page); |
127 | error: | |
128 | unlock_page(page); | |
129 | return ERR_PTR(err); | |
5274f052 JA |
130 | } |
131 | ||
132 | static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, | |
133 | struct pipe_buffer *buf) | |
134 | { | |
5274f052 JA |
135 | kunmap(buf->page); |
136 | } | |
137 | ||
912d35f8 JA |
138 | static void *user_page_pipe_buf_map(struct file *file, |
139 | struct pipe_inode_info *pipe, | |
140 | struct pipe_buffer *buf) | |
141 | { | |
142 | return kmap(buf->page); | |
143 | } | |
144 | ||
145 | static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe, | |
146 | struct pipe_buffer *buf) | |
147 | { | |
148 | kunmap(buf->page); | |
149 | } | |
150 | ||
70524490 JA |
151 | static void page_cache_pipe_buf_get(struct pipe_inode_info *info, |
152 | struct pipe_buffer *buf) | |
153 | { | |
154 | page_cache_get(buf->page); | |
155 | } | |
156 | ||
5274f052 JA |
157 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { |
158 | .can_merge = 0, | |
159 | .map = page_cache_pipe_buf_map, | |
160 | .unmap = page_cache_pipe_buf_unmap, | |
161 | .release = page_cache_pipe_buf_release, | |
5abc97aa | 162 | .steal = page_cache_pipe_buf_steal, |
70524490 | 163 | .get = page_cache_pipe_buf_get, |
5274f052 JA |
164 | }; |
165 | ||
912d35f8 JA |
166 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
167 | struct pipe_buffer *buf) | |
168 | { | |
169 | return 1; | |
170 | } | |
171 | ||
172 | static struct pipe_buf_operations user_page_pipe_buf_ops = { | |
173 | .can_merge = 0, | |
174 | .map = user_page_pipe_buf_map, | |
175 | .unmap = user_page_pipe_buf_unmap, | |
176 | .release = page_cache_pipe_buf_release, | |
177 | .steal = user_page_pipe_buf_steal, | |
178 | .get = page_cache_pipe_buf_get, | |
179 | }; | |
180 | ||
83f9135b JA |
181 | /* |
182 | * Pipe output worker. This sets up our pipe format with the page cache | |
183 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). | |
184 | */ | |
00522fb4 JA |
185 | static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
186 | struct splice_pipe_desc *spd) | |
5274f052 | 187 | { |
912d35f8 | 188 | int ret, do_wakeup, page_nr; |
5274f052 JA |
189 | |
190 | ret = 0; | |
191 | do_wakeup = 0; | |
912d35f8 | 192 | page_nr = 0; |
5274f052 | 193 | |
3a326a2c IM |
194 | if (pipe->inode) |
195 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 196 | |
5274f052 | 197 | for (;;) { |
3a326a2c | 198 | if (!pipe->readers) { |
5274f052 JA |
199 | send_sig(SIGPIPE, current, 0); |
200 | if (!ret) | |
201 | ret = -EPIPE; | |
202 | break; | |
203 | } | |
204 | ||
6f767b04 JA |
205 | if (pipe->nrbufs < PIPE_BUFFERS) { |
206 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); | |
3a326a2c | 207 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
5274f052 | 208 | |
912d35f8 JA |
209 | buf->page = spd->pages[page_nr]; |
210 | buf->offset = spd->partial[page_nr].offset; | |
211 | buf->len = spd->partial[page_nr].len; | |
212 | buf->ops = spd->ops; | |
6f767b04 | 213 | pipe->nrbufs++; |
912d35f8 JA |
214 | page_nr++; |
215 | ret += buf->len; | |
216 | ||
6f767b04 JA |
217 | if (pipe->inode) |
218 | do_wakeup = 1; | |
5274f052 | 219 | |
912d35f8 | 220 | if (!--spd->nr_pages) |
5274f052 | 221 | break; |
6f767b04 | 222 | if (pipe->nrbufs < PIPE_BUFFERS) |
5274f052 JA |
223 | continue; |
224 | ||
225 | break; | |
226 | } | |
227 | ||
912d35f8 | 228 | if (spd->flags & SPLICE_F_NONBLOCK) { |
29e35094 LT |
229 | if (!ret) |
230 | ret = -EAGAIN; | |
231 | break; | |
232 | } | |
233 | ||
5274f052 JA |
234 | if (signal_pending(current)) { |
235 | if (!ret) | |
236 | ret = -ERESTARTSYS; | |
237 | break; | |
238 | } | |
239 | ||
240 | if (do_wakeup) { | |
c0bd1f65 | 241 | smp_mb(); |
3a326a2c IM |
242 | if (waitqueue_active(&pipe->wait)) |
243 | wake_up_interruptible_sync(&pipe->wait); | |
244 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
245 | do_wakeup = 0; |
246 | } | |
247 | ||
3a326a2c IM |
248 | pipe->waiting_writers++; |
249 | pipe_wait(pipe); | |
250 | pipe->waiting_writers--; | |
5274f052 JA |
251 | } |
252 | ||
3a326a2c IM |
253 | if (pipe->inode) |
254 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
255 | |
256 | if (do_wakeup) { | |
c0bd1f65 | 257 | smp_mb(); |
3a326a2c IM |
258 | if (waitqueue_active(&pipe->wait)) |
259 | wake_up_interruptible(&pipe->wait); | |
260 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
261 | } |
262 | ||
912d35f8 JA |
263 | while (page_nr < spd->nr_pages) |
264 | page_cache_release(spd->pages[page_nr++]); | |
5274f052 JA |
265 | |
266 | return ret; | |
267 | } | |
268 | ||
3a326a2c | 269 | static int |
cbb7e577 JA |
270 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
271 | struct pipe_inode_info *pipe, size_t len, | |
272 | unsigned int flags) | |
5274f052 JA |
273 | { |
274 | struct address_space *mapping = in->f_mapping; | |
912d35f8 | 275 | unsigned int loff, nr_pages; |
16c523dd | 276 | struct page *pages[PIPE_BUFFERS]; |
912d35f8 | 277 | struct partial_page partial[PIPE_BUFFERS]; |
5274f052 | 278 | struct page *page; |
91ad66ef JA |
279 | pgoff_t index, end_index; |
280 | loff_t isize; | |
912d35f8 JA |
281 | size_t total_len; |
282 | int error; | |
283 | struct splice_pipe_desc spd = { | |
284 | .pages = pages, | |
285 | .partial = partial, | |
286 | .flags = flags, | |
287 | .ops = &page_cache_pipe_buf_ops, | |
288 | }; | |
5274f052 | 289 | |
cbb7e577 | 290 | index = *ppos >> PAGE_CACHE_SHIFT; |
912d35f8 JA |
291 | loff = *ppos & ~PAGE_CACHE_MASK; |
292 | nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
5274f052 JA |
293 | |
294 | if (nr_pages > PIPE_BUFFERS) | |
295 | nr_pages = PIPE_BUFFERS; | |
296 | ||
297 | /* | |
73d62d83 | 298 | * Initiate read-ahead on this page range. however, don't call into |
0b749ce3 JA |
299 | * read-ahead if this is a non-zero offset (we are likely doing small |
300 | * chunk splice and the page is already there) for a single page. | |
5274f052 | 301 | */ |
912d35f8 JA |
302 | if (!loff || spd.nr_pages > 1) |
303 | do_page_cache_readahead(mapping, in, index, spd.nr_pages); | |
5274f052 | 304 | |
5274f052 | 305 | /* |
73d62d83 | 306 | * Now fill in the holes: |
5274f052 | 307 | */ |
7480a904 | 308 | error = 0; |
912d35f8 JA |
309 | total_len = 0; |
310 | for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) { | |
82aa5d61 JA |
311 | unsigned int this_len; |
312 | ||
313 | if (!len) | |
314 | break; | |
315 | ||
316 | /* | |
317 | * this_len is the max we'll use from this page | |
318 | */ | |
ba5f5d90 | 319 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
7480a904 | 320 | find_page: |
5274f052 | 321 | /* |
7480a904 | 322 | * lookup the page for this index |
5274f052 | 323 | */ |
7480a904 JA |
324 | page = find_get_page(mapping, index); |
325 | if (!page) { | |
7480a904 JA |
326 | /* |
327 | * page didn't exist, allocate one | |
328 | */ | |
329 | page = page_cache_alloc_cold(mapping); | |
330 | if (!page) | |
331 | break; | |
332 | ||
333 | error = add_to_page_cache_lru(page, mapping, index, | |
334 | mapping_gfp_mask(mapping)); | |
335 | if (unlikely(error)) { | |
336 | page_cache_release(page); | |
337 | break; | |
338 | } | |
339 | ||
340 | goto readpage; | |
341 | } | |
342 | ||
343 | /* | |
344 | * If the page isn't uptodate, we may need to start io on it | |
345 | */ | |
346 | if (!PageUptodate(page)) { | |
c4f895cb JA |
347 | /* |
348 | * If in nonblock mode then dont block on waiting | |
349 | * for an in-flight io page | |
350 | */ | |
351 | if (flags & SPLICE_F_NONBLOCK) | |
352 | break; | |
353 | ||
7480a904 JA |
354 | lock_page(page); |
355 | ||
356 | /* | |
357 | * page was truncated, stop here. if this isn't the | |
358 | * first page, we'll just complete what we already | |
359 | * added | |
360 | */ | |
361 | if (!page->mapping) { | |
362 | unlock_page(page); | |
363 | page_cache_release(page); | |
364 | break; | |
365 | } | |
366 | /* | |
367 | * page was already under io and is now done, great | |
368 | */ | |
369 | if (PageUptodate(page)) { | |
370 | unlock_page(page); | |
371 | goto fill_it; | |
372 | } | |
5274f052 | 373 | |
7480a904 JA |
374 | readpage: |
375 | /* | |
376 | * need to read in the page | |
377 | */ | |
378 | error = mapping->a_ops->readpage(in, page); | |
5274f052 JA |
379 | |
380 | if (unlikely(error)) { | |
381 | page_cache_release(page); | |
7480a904 JA |
382 | if (error == AOP_TRUNCATED_PAGE) |
383 | goto find_page; | |
5274f052 JA |
384 | break; |
385 | } | |
91ad66ef JA |
386 | |
387 | /* | |
388 | * i_size must be checked after ->readpage(). | |
389 | */ | |
390 | isize = i_size_read(mapping->host); | |
391 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; | |
392 | if (unlikely(!isize || index > end_index)) { | |
393 | page_cache_release(page); | |
394 | break; | |
395 | } | |
396 | ||
397 | /* | |
398 | * if this is the last page, see if we need to shrink | |
399 | * the length and stop | |
400 | */ | |
401 | if (end_index == index) { | |
402 | loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); | |
912d35f8 | 403 | if (total_len + loff > isize) { |
91ad66ef JA |
404 | page_cache_release(page); |
405 | break; | |
406 | } | |
407 | /* | |
408 | * force quit after adding this page | |
409 | */ | |
912d35f8 | 410 | nr_pages = spd.nr_pages; |
82aa5d61 | 411 | this_len = min(this_len, loff); |
912d35f8 | 412 | loff = 0; |
91ad66ef | 413 | } |
5274f052 | 414 | } |
7480a904 | 415 | fill_it: |
912d35f8 JA |
416 | pages[spd.nr_pages] = page; |
417 | partial[spd.nr_pages].offset = loff; | |
418 | partial[spd.nr_pages].len = this_len; | |
82aa5d61 | 419 | len -= this_len; |
912d35f8 | 420 | total_len += this_len; |
91ad66ef | 421 | loff = 0; |
5274f052 JA |
422 | } |
423 | ||
912d35f8 | 424 | if (spd.nr_pages) |
00522fb4 | 425 | return splice_to_pipe(pipe, &spd); |
5274f052 | 426 | |
7480a904 | 427 | return error; |
5274f052 JA |
428 | } |
429 | ||
83f9135b JA |
430 | /** |
431 | * generic_file_splice_read - splice data from file to a pipe | |
432 | * @in: file to splice from | |
433 | * @pipe: pipe to splice to | |
434 | * @len: number of bytes to splice | |
435 | * @flags: splice modifier flags | |
436 | * | |
437 | * Will read pages from given file and fill them into a pipe. | |
83f9135b | 438 | */ |
cbb7e577 JA |
439 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
440 | struct pipe_inode_info *pipe, size_t len, | |
441 | unsigned int flags) | |
5274f052 JA |
442 | { |
443 | ssize_t spliced; | |
444 | int ret; | |
445 | ||
446 | ret = 0; | |
447 | spliced = 0; | |
3a326a2c | 448 | |
5274f052 | 449 | while (len) { |
cbb7e577 | 450 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
5274f052 | 451 | |
c4f895cb | 452 | if (ret < 0) |
5274f052 | 453 | break; |
c4f895cb JA |
454 | else if (!ret) { |
455 | if (spliced) | |
456 | break; | |
457 | if (flags & SPLICE_F_NONBLOCK) { | |
458 | ret = -EAGAIN; | |
459 | break; | |
460 | } | |
461 | } | |
5274f052 | 462 | |
cbb7e577 | 463 | *ppos += ret; |
5274f052 JA |
464 | len -= ret; |
465 | spliced += ret; | |
466 | } | |
467 | ||
468 | if (spliced) | |
469 | return spliced; | |
470 | ||
471 | return ret; | |
472 | } | |
473 | ||
059a8f37 JA |
474 | EXPORT_SYMBOL(generic_file_splice_read); |
475 | ||
5274f052 | 476 | /* |
4f6f0bd2 | 477 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
016b661e | 478 | * using sendpage(). Return the number of bytes sent. |
5274f052 JA |
479 | */ |
480 | static int pipe_to_sendpage(struct pipe_inode_info *info, | |
481 | struct pipe_buffer *buf, struct splice_desc *sd) | |
482 | { | |
483 | struct file *file = sd->file; | |
484 | loff_t pos = sd->pos; | |
5274f052 JA |
485 | ssize_t ret; |
486 | void *ptr; | |
b2b39fa4 | 487 | int more; |
5274f052 JA |
488 | |
489 | /* | |
73d62d83 | 490 | * Sub-optimal, but we are limited by the pipe ->map. We don't |
5274f052 JA |
491 | * need a kmap'ed buffer here, we just want to make sure we |
492 | * have the page pinned if the pipe page originates from the | |
73d62d83 | 493 | * page cache. |
5274f052 JA |
494 | */ |
495 | ptr = buf->ops->map(file, info, buf); | |
496 | if (IS_ERR(ptr)) | |
497 | return PTR_ERR(ptr); | |
498 | ||
b2b39fa4 | 499 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
5274f052 | 500 | |
016b661e JA |
501 | ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len, |
502 | &pos, more); | |
5274f052 JA |
503 | |
504 | buf->ops->unmap(info, buf); | |
016b661e | 505 | return ret; |
5274f052 JA |
506 | } |
507 | ||
508 | /* | |
509 | * This is a little more tricky than the file -> pipe splicing. There are | |
510 | * basically three cases: | |
511 | * | |
512 | * - Destination page already exists in the address space and there | |
513 | * are users of it. For that case we have no other option that | |
514 | * copying the data. Tough luck. | |
515 | * - Destination page already exists in the address space, but there | |
516 | * are no users of it. Make sure it's uptodate, then drop it. Fall | |
517 | * through to last case. | |
518 | * - Destination page does not exist, we can add the pipe page to | |
519 | * the page cache and avoid the copy. | |
520 | * | |
83f9135b JA |
521 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
522 | * sd->flags), we attempt to migrate pages from the pipe to the output | |
523 | * file address space page cache. This is possible if no one else has | |
524 | * the pipe page referenced outside of the pipe and page cache. If | |
525 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create | |
526 | * a new page in the output file page cache and fill/dirty that. | |
5274f052 JA |
527 | */ |
528 | static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, | |
529 | struct splice_desc *sd) | |
530 | { | |
531 | struct file *file = sd->file; | |
532 | struct address_space *mapping = file->f_mapping; | |
3e7ee3e7 | 533 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
016b661e | 534 | unsigned int offset, this_len; |
5274f052 | 535 | struct page *page; |
5274f052 | 536 | pgoff_t index; |
5abc97aa | 537 | char *src; |
3e7ee3e7 | 538 | int ret; |
5274f052 JA |
539 | |
540 | /* | |
49d0b21b | 541 | * make sure the data in this buffer is uptodate |
5274f052 JA |
542 | */ |
543 | src = buf->ops->map(file, info, buf); | |
544 | if (IS_ERR(src)) | |
545 | return PTR_ERR(src); | |
546 | ||
547 | index = sd->pos >> PAGE_CACHE_SHIFT; | |
548 | offset = sd->pos & ~PAGE_CACHE_MASK; | |
549 | ||
016b661e JA |
550 | this_len = sd->len; |
551 | if (this_len + offset > PAGE_CACHE_SIZE) | |
552 | this_len = PAGE_CACHE_SIZE - offset; | |
553 | ||
5274f052 | 554 | /* |
73d62d83 | 555 | * Reuse buf page, if SPLICE_F_MOVE is set. |
5274f052 | 556 | */ |
5abc97aa | 557 | if (sd->flags & SPLICE_F_MOVE) { |
83f9135b JA |
558 | /* |
559 | * If steal succeeds, buf->page is now pruned from the vm | |
9e0267c2 JA |
560 | * side (LRU and page cache) and we can reuse it. The page |
561 | * will also be looked on successful return. | |
83f9135b | 562 | */ |
5abc97aa JA |
563 | if (buf->ops->steal(info, buf)) |
564 | goto find_page; | |
565 | ||
566 | page = buf->page; | |
3e7ee3e7 | 567 | if (add_to_page_cache(page, mapping, index, gfp_mask)) |
5abc97aa | 568 | goto find_page; |
3e7ee3e7 JA |
569 | |
570 | if (!(buf->flags & PIPE_BUF_FLAG_LRU)) | |
571 | lru_cache_add(page); | |
5abc97aa JA |
572 | } else { |
573 | find_page: | |
9e0267c2 JA |
574 | page = find_lock_page(mapping, index); |
575 | if (!page) { | |
576 | ret = -ENOMEM; | |
577 | page = page_cache_alloc_cold(mapping); | |
578 | if (unlikely(!page)) | |
579 | goto out_nomem; | |
580 | ||
581 | /* | |
582 | * This will also lock the page | |
583 | */ | |
584 | ret = add_to_page_cache_lru(page, mapping, index, | |
585 | gfp_mask); | |
586 | if (unlikely(ret)) | |
587 | goto out; | |
588 | } | |
5abc97aa JA |
589 | |
590 | /* | |
9e0267c2 JA |
591 | * We get here with the page locked. If the page is also |
592 | * uptodate, we don't need to do more. If it isn't, we | |
593 | * may need to bring it in if we are not going to overwrite | |
594 | * the full page. | |
5abc97aa JA |
595 | */ |
596 | if (!PageUptodate(page)) { | |
016b661e | 597 | if (this_len < PAGE_CACHE_SIZE) { |
5abc97aa JA |
598 | ret = mapping->a_ops->readpage(file, page); |
599 | if (unlikely(ret)) | |
600 | goto out; | |
601 | ||
602 | lock_page(page); | |
603 | ||
604 | if (!PageUptodate(page)) { | |
605 | /* | |
73d62d83 | 606 | * Page got invalidated, repeat. |
5abc97aa JA |
607 | */ |
608 | if (!page->mapping) { | |
609 | unlock_page(page); | |
610 | page_cache_release(page); | |
611 | goto find_page; | |
612 | } | |
613 | ret = -EIO; | |
614 | goto out; | |
5274f052 | 615 | } |
9e0267c2 | 616 | } else |
5abc97aa | 617 | SetPageUptodate(page); |
5274f052 JA |
618 | } |
619 | } | |
620 | ||
016b661e | 621 | ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); |
4f6f0bd2 JA |
622 | if (ret == AOP_TRUNCATED_PAGE) { |
623 | page_cache_release(page); | |
624 | goto find_page; | |
625 | } else if (ret) | |
5274f052 JA |
626 | goto out; |
627 | ||
3e7ee3e7 | 628 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { |
5abc97aa JA |
629 | char *dst = kmap_atomic(page, KM_USER0); |
630 | ||
016b661e | 631 | memcpy(dst + offset, src + buf->offset, this_len); |
5abc97aa JA |
632 | flush_dcache_page(page); |
633 | kunmap_atomic(dst, KM_USER0); | |
634 | } | |
5274f052 | 635 | |
016b661e | 636 | ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); |
4f6f0bd2 JA |
637 | if (ret == AOP_TRUNCATED_PAGE) { |
638 | page_cache_release(page); | |
639 | goto find_page; | |
640 | } else if (ret) | |
5274f052 JA |
641 | goto out; |
642 | ||
016b661e JA |
643 | /* |
644 | * Return the number of bytes written. | |
645 | */ | |
646 | ret = this_len; | |
c7f21e4f | 647 | mark_page_accessed(page); |
4f6f0bd2 | 648 | balance_dirty_pages_ratelimited(mapping); |
5274f052 | 649 | out: |
9e0267c2 | 650 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) |
5abc97aa | 651 | page_cache_release(page); |
9e0267c2 JA |
652 | |
653 | unlock_page(page); | |
9aefe431 | 654 | out_nomem: |
5274f052 JA |
655 | buf->ops->unmap(info, buf); |
656 | return ret; | |
657 | } | |
658 | ||
83f9135b JA |
659 | /* |
660 | * Pipe input worker. Most of this logic works like a regular pipe, the | |
661 | * key here is the 'actor' worker passed in that actually moves the data | |
662 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. | |
663 | */ | |
00522fb4 JA |
664 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
665 | loff_t *ppos, size_t len, unsigned int flags, | |
666 | splice_actor *actor) | |
5274f052 | 667 | { |
5274f052 JA |
668 | int ret, do_wakeup, err; |
669 | struct splice_desc sd; | |
670 | ||
671 | ret = 0; | |
672 | do_wakeup = 0; | |
673 | ||
674 | sd.total_len = len; | |
675 | sd.flags = flags; | |
676 | sd.file = out; | |
cbb7e577 | 677 | sd.pos = *ppos; |
5274f052 | 678 | |
3a326a2c IM |
679 | if (pipe->inode) |
680 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 681 | |
5274f052 | 682 | for (;;) { |
6f767b04 JA |
683 | if (pipe->nrbufs) { |
684 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; | |
5274f052 JA |
685 | struct pipe_buf_operations *ops = buf->ops; |
686 | ||
687 | sd.len = buf->len; | |
688 | if (sd.len > sd.total_len) | |
689 | sd.len = sd.total_len; | |
690 | ||
3a326a2c | 691 | err = actor(pipe, buf, &sd); |
016b661e | 692 | if (err <= 0) { |
5274f052 JA |
693 | if (!ret && err != -ENODATA) |
694 | ret = err; | |
695 | ||
696 | break; | |
697 | } | |
698 | ||
016b661e JA |
699 | ret += err; |
700 | buf->offset += err; | |
701 | buf->len -= err; | |
702 | ||
703 | sd.len -= err; | |
704 | sd.pos += err; | |
705 | sd.total_len -= err; | |
706 | if (sd.len) | |
707 | continue; | |
73d62d83 | 708 | |
5274f052 JA |
709 | if (!buf->len) { |
710 | buf->ops = NULL; | |
3a326a2c | 711 | ops->release(pipe, buf); |
6f767b04 JA |
712 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
713 | pipe->nrbufs--; | |
714 | if (pipe->inode) | |
715 | do_wakeup = 1; | |
5274f052 JA |
716 | } |
717 | ||
5274f052 JA |
718 | if (!sd.total_len) |
719 | break; | |
720 | } | |
721 | ||
6f767b04 | 722 | if (pipe->nrbufs) |
5274f052 | 723 | continue; |
3a326a2c | 724 | if (!pipe->writers) |
5274f052 | 725 | break; |
3a326a2c | 726 | if (!pipe->waiting_writers) { |
5274f052 JA |
727 | if (ret) |
728 | break; | |
729 | } | |
730 | ||
29e35094 LT |
731 | if (flags & SPLICE_F_NONBLOCK) { |
732 | if (!ret) | |
733 | ret = -EAGAIN; | |
734 | break; | |
735 | } | |
736 | ||
5274f052 JA |
737 | if (signal_pending(current)) { |
738 | if (!ret) | |
739 | ret = -ERESTARTSYS; | |
740 | break; | |
741 | } | |
742 | ||
743 | if (do_wakeup) { | |
c0bd1f65 | 744 | smp_mb(); |
3a326a2c IM |
745 | if (waitqueue_active(&pipe->wait)) |
746 | wake_up_interruptible_sync(&pipe->wait); | |
747 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
748 | do_wakeup = 0; |
749 | } | |
750 | ||
3a326a2c | 751 | pipe_wait(pipe); |
5274f052 JA |
752 | } |
753 | ||
3a326a2c IM |
754 | if (pipe->inode) |
755 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
756 | |
757 | if (do_wakeup) { | |
c0bd1f65 | 758 | smp_mb(); |
3a326a2c IM |
759 | if (waitqueue_active(&pipe->wait)) |
760 | wake_up_interruptible(&pipe->wait); | |
761 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
762 | } |
763 | ||
5274f052 | 764 | return ret; |
5274f052 JA |
765 | } |
766 | ||
83f9135b JA |
767 | /** |
768 | * generic_file_splice_write - splice data from a pipe to a file | |
3a326a2c | 769 | * @pipe: pipe info |
83f9135b JA |
770 | * @out: file to write to |
771 | * @len: number of bytes to splice | |
772 | * @flags: splice modifier flags | |
773 | * | |
774 | * Will either move or copy pages (determined by @flags options) from | |
775 | * the given pipe inode to the given file. | |
776 | * | |
777 | */ | |
3a326a2c IM |
778 | ssize_t |
779 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, | |
cbb7e577 | 780 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 781 | { |
4f6f0bd2 | 782 | struct address_space *mapping = out->f_mapping; |
3a326a2c IM |
783 | ssize_t ret; |
784 | ||
00522fb4 | 785 | ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
a4514ebd | 786 | if (ret > 0) { |
4f6f0bd2 | 787 | struct inode *inode = mapping->host; |
4f6f0bd2 | 788 | |
a4514ebd JA |
789 | *ppos += ret; |
790 | ||
791 | /* | |
792 | * If file or inode is SYNC and we actually wrote some data, | |
793 | * sync it. | |
794 | */ | |
795 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { | |
796 | int err; | |
797 | ||
798 | mutex_lock(&inode->i_mutex); | |
799 | err = generic_osync_inode(inode, mapping, | |
800 | OSYNC_METADATA|OSYNC_DATA); | |
801 | mutex_unlock(&inode->i_mutex); | |
4f6f0bd2 | 802 | |
a4514ebd JA |
803 | if (err) |
804 | ret = err; | |
805 | } | |
4f6f0bd2 JA |
806 | } |
807 | ||
808 | return ret; | |
5274f052 JA |
809 | } |
810 | ||
059a8f37 JA |
811 | EXPORT_SYMBOL(generic_file_splice_write); |
812 | ||
83f9135b JA |
813 | /** |
814 | * generic_splice_sendpage - splice data from a pipe to a socket | |
815 | * @inode: pipe inode | |
816 | * @out: socket to write to | |
817 | * @len: number of bytes to splice | |
818 | * @flags: splice modifier flags | |
819 | * | |
820 | * Will send @len bytes from the pipe to a network socket. No data copying | |
821 | * is involved. | |
822 | * | |
823 | */ | |
3a326a2c | 824 | ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 825 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 826 | { |
00522fb4 | 827 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
5274f052 JA |
828 | } |
829 | ||
059a8f37 | 830 | EXPORT_SYMBOL(generic_splice_sendpage); |
a0f06780 | 831 | |
83f9135b JA |
832 | /* |
833 | * Attempt to initiate a splice from pipe to file. | |
834 | */ | |
3a326a2c | 835 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 836 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 837 | { |
5274f052 JA |
838 | int ret; |
839 | ||
49570e9b | 840 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
5274f052 JA |
841 | return -EINVAL; |
842 | ||
49570e9b | 843 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
5274f052 JA |
844 | return -EBADF; |
845 | ||
cbb7e577 | 846 | ret = rw_verify_area(WRITE, out, ppos, len); |
5274f052 JA |
847 | if (unlikely(ret < 0)) |
848 | return ret; | |
849 | ||
cbb7e577 | 850 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
5274f052 JA |
851 | } |
852 | ||
83f9135b JA |
853 | /* |
854 | * Attempt to initiate a splice from a file to a pipe. | |
855 | */ | |
cbb7e577 JA |
856 | static long do_splice_to(struct file *in, loff_t *ppos, |
857 | struct pipe_inode_info *pipe, size_t len, | |
858 | unsigned int flags) | |
5274f052 | 859 | { |
cbb7e577 | 860 | loff_t isize, left; |
5274f052 JA |
861 | int ret; |
862 | ||
49570e9b | 863 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
5274f052 JA |
864 | return -EINVAL; |
865 | ||
49570e9b | 866 | if (unlikely(!(in->f_mode & FMODE_READ))) |
5274f052 JA |
867 | return -EBADF; |
868 | ||
cbb7e577 | 869 | ret = rw_verify_area(READ, in, ppos, len); |
5274f052 JA |
870 | if (unlikely(ret < 0)) |
871 | return ret; | |
872 | ||
873 | isize = i_size_read(in->f_mapping->host); | |
cbb7e577 | 874 | if (unlikely(*ppos >= isize)) |
5274f052 JA |
875 | return 0; |
876 | ||
cbb7e577 | 877 | left = isize - *ppos; |
49570e9b | 878 | if (unlikely(left < len)) |
5274f052 JA |
879 | len = left; |
880 | ||
cbb7e577 | 881 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
5274f052 JA |
882 | } |
883 | ||
cbb7e577 JA |
884 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
885 | size_t len, unsigned int flags) | |
b92ce558 JA |
886 | { |
887 | struct pipe_inode_info *pipe; | |
888 | long ret, bytes; | |
cbb7e577 | 889 | loff_t out_off; |
b92ce558 JA |
890 | umode_t i_mode; |
891 | int i; | |
892 | ||
893 | /* | |
894 | * We require the input being a regular file, as we don't want to | |
895 | * randomly drop data for eg socket -> socket splicing. Use the | |
896 | * piped splicing for that! | |
897 | */ | |
898 | i_mode = in->f_dentry->d_inode->i_mode; | |
899 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) | |
900 | return -EINVAL; | |
901 | ||
902 | /* | |
903 | * neither in nor out is a pipe, setup an internal pipe attached to | |
904 | * 'out' and transfer the wanted data from 'in' to 'out' through that | |
905 | */ | |
906 | pipe = current->splice_pipe; | |
49570e9b | 907 | if (unlikely(!pipe)) { |
b92ce558 JA |
908 | pipe = alloc_pipe_info(NULL); |
909 | if (!pipe) | |
910 | return -ENOMEM; | |
911 | ||
912 | /* | |
913 | * We don't have an immediate reader, but we'll read the stuff | |
00522fb4 | 914 | * out of the pipe right after the splice_to_pipe(). So set |
b92ce558 JA |
915 | * PIPE_READERS appropriately. |
916 | */ | |
917 | pipe->readers = 1; | |
918 | ||
919 | current->splice_pipe = pipe; | |
920 | } | |
921 | ||
922 | /* | |
73d62d83 | 923 | * Do the splice. |
b92ce558 JA |
924 | */ |
925 | ret = 0; | |
926 | bytes = 0; | |
cbb7e577 | 927 | out_off = 0; |
b92ce558 JA |
928 | |
929 | while (len) { | |
930 | size_t read_len, max_read_len; | |
931 | ||
932 | /* | |
933 | * Do at most PIPE_BUFFERS pages worth of transfer: | |
934 | */ | |
935 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); | |
936 | ||
cbb7e577 | 937 | ret = do_splice_to(in, ppos, pipe, max_read_len, flags); |
b92ce558 JA |
938 | if (unlikely(ret < 0)) |
939 | goto out_release; | |
940 | ||
941 | read_len = ret; | |
942 | ||
943 | /* | |
944 | * NOTE: nonblocking mode only applies to the input. We | |
945 | * must not do the output in nonblocking mode as then we | |
946 | * could get stuck data in the internal pipe: | |
947 | */ | |
cbb7e577 | 948 | ret = do_splice_from(pipe, out, &out_off, read_len, |
b92ce558 JA |
949 | flags & ~SPLICE_F_NONBLOCK); |
950 | if (unlikely(ret < 0)) | |
951 | goto out_release; | |
952 | ||
953 | bytes += ret; | |
954 | len -= ret; | |
955 | ||
956 | /* | |
957 | * In nonblocking mode, if we got back a short read then | |
958 | * that was due to either an IO error or due to the | |
959 | * pagecache entry not being there. In the IO error case | |
960 | * the _next_ splice attempt will produce a clean IO error | |
961 | * return value (not a short read), so in both cases it's | |
962 | * correct to break out of the loop here: | |
963 | */ | |
964 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) | |
965 | break; | |
966 | } | |
967 | ||
968 | pipe->nrbufs = pipe->curbuf = 0; | |
969 | ||
970 | return bytes; | |
971 | ||
972 | out_release: | |
973 | /* | |
974 | * If we did an incomplete transfer we must release | |
975 | * the pipe buffers in question: | |
976 | */ | |
977 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
978 | struct pipe_buffer *buf = pipe->bufs + i; | |
979 | ||
980 | if (buf->ops) { | |
981 | buf->ops->release(pipe, buf); | |
982 | buf->ops = NULL; | |
983 | } | |
984 | } | |
985 | pipe->nrbufs = pipe->curbuf = 0; | |
986 | ||
987 | /* | |
988 | * If we transferred some data, return the number of bytes: | |
989 | */ | |
990 | if (bytes > 0) | |
991 | return bytes; | |
992 | ||
993 | return ret; | |
994 | } | |
995 | ||
996 | EXPORT_SYMBOL(do_splice_direct); | |
997 | ||
83f9135b JA |
998 | /* |
999 | * Determine where to splice to/from. | |
1000 | */ | |
529565dc IM |
1001 | static long do_splice(struct file *in, loff_t __user *off_in, |
1002 | struct file *out, loff_t __user *off_out, | |
1003 | size_t len, unsigned int flags) | |
5274f052 | 1004 | { |
3a326a2c | 1005 | struct pipe_inode_info *pipe; |
cbb7e577 | 1006 | loff_t offset, *off; |
a4514ebd | 1007 | long ret; |
5274f052 | 1008 | |
3a326a2c | 1009 | pipe = in->f_dentry->d_inode->i_pipe; |
529565dc IM |
1010 | if (pipe) { |
1011 | if (off_in) | |
1012 | return -ESPIPE; | |
b92ce558 JA |
1013 | if (off_out) { |
1014 | if (out->f_op->llseek == no_llseek) | |
1015 | return -EINVAL; | |
cbb7e577 | 1016 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
b92ce558 | 1017 | return -EFAULT; |
cbb7e577 JA |
1018 | off = &offset; |
1019 | } else | |
1020 | off = &out->f_pos; | |
529565dc | 1021 | |
a4514ebd JA |
1022 | ret = do_splice_from(pipe, out, off, len, flags); |
1023 | ||
1024 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) | |
1025 | ret = -EFAULT; | |
1026 | ||
1027 | return ret; | |
529565dc | 1028 | } |
5274f052 | 1029 | |
3a326a2c | 1030 | pipe = out->f_dentry->d_inode->i_pipe; |
529565dc IM |
1031 | if (pipe) { |
1032 | if (off_out) | |
1033 | return -ESPIPE; | |
b92ce558 JA |
1034 | if (off_in) { |
1035 | if (in->f_op->llseek == no_llseek) | |
1036 | return -EINVAL; | |
cbb7e577 | 1037 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
b92ce558 | 1038 | return -EFAULT; |
cbb7e577 JA |
1039 | off = &offset; |
1040 | } else | |
1041 | off = &in->f_pos; | |
529565dc | 1042 | |
a4514ebd JA |
1043 | ret = do_splice_to(in, off, pipe, len, flags); |
1044 | ||
1045 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) | |
1046 | ret = -EFAULT; | |
1047 | ||
1048 | return ret; | |
529565dc | 1049 | } |
5274f052 JA |
1050 | |
1051 | return -EINVAL; | |
1052 | } | |
1053 | ||
912d35f8 JA |
1054 | /* |
1055 | * Map an iov into an array of pages and offset/length tupples. With the | |
1056 | * partial_page structure, we can map several non-contiguous ranges into | |
1057 | * our ones pages[] map instead of splitting that operation into pieces. | |
1058 | * Could easily be exported as a generic helper for other users, in which | |
1059 | * case one would probably want to add a 'max_nr_pages' parameter as well. | |
1060 | */ | |
1061 | static int get_iovec_page_array(const struct iovec __user *iov, | |
1062 | unsigned int nr_vecs, struct page **pages, | |
1063 | struct partial_page *partial) | |
1064 | { | |
1065 | int buffers = 0, error = 0; | |
1066 | ||
1067 | /* | |
1068 | * It's ok to take the mmap_sem for reading, even | |
1069 | * across a "get_user()". | |
1070 | */ | |
1071 | down_read(¤t->mm->mmap_sem); | |
1072 | ||
1073 | while (nr_vecs) { | |
1074 | unsigned long off, npages; | |
1075 | void __user *base; | |
1076 | size_t len; | |
1077 | int i; | |
1078 | ||
1079 | /* | |
1080 | * Get user address base and length for this iovec. | |
1081 | */ | |
1082 | error = get_user(base, &iov->iov_base); | |
1083 | if (unlikely(error)) | |
1084 | break; | |
1085 | error = get_user(len, &iov->iov_len); | |
1086 | if (unlikely(error)) | |
1087 | break; | |
1088 | ||
1089 | /* | |
1090 | * Sanity check this iovec. 0 read succeeds. | |
1091 | */ | |
1092 | if (unlikely(!len)) | |
1093 | break; | |
1094 | error = -EFAULT; | |
1095 | if (unlikely(!base)) | |
1096 | break; | |
1097 | ||
1098 | /* | |
1099 | * Get this base offset and number of pages, then map | |
1100 | * in the user pages. | |
1101 | */ | |
1102 | off = (unsigned long) base & ~PAGE_MASK; | |
1103 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1104 | if (npages > PIPE_BUFFERS - buffers) | |
1105 | npages = PIPE_BUFFERS - buffers; | |
1106 | ||
1107 | error = get_user_pages(current, current->mm, | |
1108 | (unsigned long) base, npages, 0, 0, | |
1109 | &pages[buffers], NULL); | |
1110 | ||
1111 | if (unlikely(error <= 0)) | |
1112 | break; | |
1113 | ||
1114 | /* | |
1115 | * Fill this contiguous range into the partial page map. | |
1116 | */ | |
1117 | for (i = 0; i < error; i++) { | |
1118 | const int plen = min_t(size_t, len, PAGE_SIZE) - off; | |
1119 | ||
1120 | partial[buffers].offset = off; | |
1121 | partial[buffers].len = plen; | |
1122 | ||
1123 | off = 0; | |
1124 | len -= plen; | |
1125 | buffers++; | |
1126 | } | |
1127 | ||
1128 | /* | |
1129 | * We didn't complete this iov, stop here since it probably | |
1130 | * means we have to move some of this into a pipe to | |
1131 | * be able to continue. | |
1132 | */ | |
1133 | if (len) | |
1134 | break; | |
1135 | ||
1136 | /* | |
1137 | * Don't continue if we mapped fewer pages than we asked for, | |
1138 | * or if we mapped the max number of pages that we have | |
1139 | * room for. | |
1140 | */ | |
1141 | if (error < npages || buffers == PIPE_BUFFERS) | |
1142 | break; | |
1143 | ||
1144 | nr_vecs--; | |
1145 | iov++; | |
1146 | } | |
1147 | ||
1148 | up_read(¤t->mm->mmap_sem); | |
1149 | ||
1150 | if (buffers) | |
1151 | return buffers; | |
1152 | ||
1153 | return error; | |
1154 | } | |
1155 | ||
1156 | /* | |
1157 | * vmsplice splices a user address range into a pipe. It can be thought of | |
1158 | * as splice-from-memory, where the regular splice is splice-from-file (or | |
1159 | * to file). In both cases the output is a pipe, naturally. | |
1160 | * | |
1161 | * Note that vmsplice only supports splicing _from_ user memory to a pipe, | |
1162 | * not the other way around. Splicing from user memory is a simple operation | |
1163 | * that can be supported without any funky alignment restrictions or nasty | |
1164 | * vm tricks. We simply map in the user memory and fill them into a pipe. | |
1165 | * The reverse isn't quite as easy, though. There are two possible solutions | |
1166 | * for that: | |
1167 | * | |
1168 | * - memcpy() the data internally, at which point we might as well just | |
1169 | * do a regular read() on the buffer anyway. | |
1170 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it | |
1171 | * has restriction limitations on both ends of the pipe). | |
1172 | * | |
1173 | * Alas, it isn't here. | |
1174 | * | |
1175 | */ | |
1176 | static long do_vmsplice(struct file *file, const struct iovec __user *iov, | |
1177 | unsigned long nr_segs, unsigned int flags) | |
1178 | { | |
1179 | struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; | |
1180 | struct page *pages[PIPE_BUFFERS]; | |
1181 | struct partial_page partial[PIPE_BUFFERS]; | |
1182 | struct splice_pipe_desc spd = { | |
1183 | .pages = pages, | |
1184 | .partial = partial, | |
1185 | .flags = flags, | |
1186 | .ops = &user_page_pipe_buf_ops, | |
1187 | }; | |
1188 | ||
1189 | if (unlikely(!pipe)) | |
1190 | return -EBADF; | |
1191 | if (unlikely(nr_segs > UIO_MAXIOV)) | |
1192 | return -EINVAL; | |
1193 | else if (unlikely(!nr_segs)) | |
1194 | return 0; | |
1195 | ||
1196 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial); | |
1197 | if (spd.nr_pages <= 0) | |
1198 | return spd.nr_pages; | |
1199 | ||
00522fb4 | 1200 | return splice_to_pipe(pipe, &spd); |
912d35f8 JA |
1201 | } |
1202 | ||
1203 | asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, | |
1204 | unsigned long nr_segs, unsigned int flags) | |
1205 | { | |
1206 | struct file *file; | |
1207 | long error; | |
1208 | int fput; | |
1209 | ||
1210 | error = -EBADF; | |
1211 | file = fget_light(fd, &fput); | |
1212 | if (file) { | |
1213 | if (file->f_mode & FMODE_WRITE) | |
1214 | error = do_vmsplice(file, iov, nr_segs, flags); | |
1215 | ||
1216 | fput_light(file, fput); | |
1217 | } | |
1218 | ||
1219 | return error; | |
1220 | } | |
1221 | ||
529565dc IM |
1222 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
1223 | int fd_out, loff_t __user *off_out, | |
1224 | size_t len, unsigned int flags) | |
5274f052 JA |
1225 | { |
1226 | long error; | |
1227 | struct file *in, *out; | |
1228 | int fput_in, fput_out; | |
1229 | ||
1230 | if (unlikely(!len)) | |
1231 | return 0; | |
1232 | ||
1233 | error = -EBADF; | |
529565dc | 1234 | in = fget_light(fd_in, &fput_in); |
5274f052 JA |
1235 | if (in) { |
1236 | if (in->f_mode & FMODE_READ) { | |
529565dc | 1237 | out = fget_light(fd_out, &fput_out); |
5274f052 JA |
1238 | if (out) { |
1239 | if (out->f_mode & FMODE_WRITE) | |
529565dc IM |
1240 | error = do_splice(in, off_in, |
1241 | out, off_out, | |
1242 | len, flags); | |
5274f052 JA |
1243 | fput_light(out, fput_out); |
1244 | } | |
1245 | } | |
1246 | ||
1247 | fput_light(in, fput_in); | |
1248 | } | |
1249 | ||
1250 | return error; | |
1251 | } | |
70524490 JA |
1252 | |
1253 | /* | |
1254 | * Link contents of ipipe to opipe. | |
1255 | */ | |
1256 | static int link_pipe(struct pipe_inode_info *ipipe, | |
1257 | struct pipe_inode_info *opipe, | |
1258 | size_t len, unsigned int flags) | |
1259 | { | |
1260 | struct pipe_buffer *ibuf, *obuf; | |
2a27250e JA |
1261 | int ret, do_wakeup, i, ipipe_first; |
1262 | ||
1263 | ret = do_wakeup = ipipe_first = 0; | |
70524490 JA |
1264 | |
1265 | /* | |
1266 | * Potential ABBA deadlock, work around it by ordering lock | |
1267 | * grabbing by inode address. Otherwise two different processes | |
1268 | * could deadlock (one doing tee from A -> B, the other from B -> A). | |
1269 | */ | |
1270 | if (ipipe->inode < opipe->inode) { | |
2a27250e | 1271 | ipipe_first = 1; |
70524490 JA |
1272 | mutex_lock(&ipipe->inode->i_mutex); |
1273 | mutex_lock(&opipe->inode->i_mutex); | |
1274 | } else { | |
1275 | mutex_lock(&opipe->inode->i_mutex); | |
1276 | mutex_lock(&ipipe->inode->i_mutex); | |
1277 | } | |
1278 | ||
1279 | for (i = 0;; i++) { | |
1280 | if (!opipe->readers) { | |
1281 | send_sig(SIGPIPE, current, 0); | |
1282 | if (!ret) | |
1283 | ret = -EPIPE; | |
1284 | break; | |
1285 | } | |
1286 | if (ipipe->nrbufs - i) { | |
1287 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); | |
1288 | ||
1289 | /* | |
1290 | * If we have room, fill this buffer | |
1291 | */ | |
1292 | if (opipe->nrbufs < PIPE_BUFFERS) { | |
1293 | int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); | |
1294 | ||
1295 | /* | |
1296 | * Get a reference to this pipe buffer, | |
1297 | * so we can copy the contents over. | |
1298 | */ | |
1299 | ibuf->ops->get(ipipe, ibuf); | |
1300 | ||
1301 | obuf = opipe->bufs + nbuf; | |
1302 | *obuf = *ibuf; | |
1303 | ||
1304 | if (obuf->len > len) | |
1305 | obuf->len = len; | |
1306 | ||
1307 | opipe->nrbufs++; | |
1308 | do_wakeup = 1; | |
1309 | ret += obuf->len; | |
1310 | len -= obuf->len; | |
1311 | ||
1312 | if (!len) | |
1313 | break; | |
1314 | if (opipe->nrbufs < PIPE_BUFFERS) | |
1315 | continue; | |
1316 | } | |
1317 | ||
1318 | /* | |
1319 | * We have input available, but no output room. | |
2a27250e JA |
1320 | * If we already copied data, return that. If we |
1321 | * need to drop the opipe lock, it must be ordered | |
1322 | * last to avoid deadlocks. | |
70524490 | 1323 | */ |
2a27250e | 1324 | if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { |
70524490 JA |
1325 | if (!ret) |
1326 | ret = -EAGAIN; | |
1327 | break; | |
1328 | } | |
1329 | if (signal_pending(current)) { | |
1330 | if (!ret) | |
1331 | ret = -ERESTARTSYS; | |
1332 | break; | |
1333 | } | |
1334 | if (do_wakeup) { | |
1335 | smp_mb(); | |
1336 | if (waitqueue_active(&opipe->wait)) | |
1337 | wake_up_interruptible(&opipe->wait); | |
1338 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); | |
1339 | do_wakeup = 0; | |
1340 | } | |
1341 | ||
1342 | opipe->waiting_writers++; | |
1343 | pipe_wait(opipe); | |
1344 | opipe->waiting_writers--; | |
1345 | continue; | |
1346 | } | |
1347 | ||
1348 | /* | |
1349 | * No input buffers, do the usual checks for available | |
1350 | * writers and blocking and wait if necessary | |
1351 | */ | |
1352 | if (!ipipe->writers) | |
1353 | break; | |
1354 | if (!ipipe->waiting_writers) { | |
1355 | if (ret) | |
1356 | break; | |
1357 | } | |
2a27250e JA |
1358 | /* |
1359 | * pipe_wait() drops the ipipe mutex. To avoid deadlocks | |
1360 | * with another process, we can only safely do that if | |
1361 | * the ipipe lock is ordered last. | |
1362 | */ | |
1363 | if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { | |
70524490 JA |
1364 | if (!ret) |
1365 | ret = -EAGAIN; | |
1366 | break; | |
1367 | } | |
1368 | if (signal_pending(current)) { | |
1369 | if (!ret) | |
1370 | ret = -ERESTARTSYS; | |
1371 | break; | |
1372 | } | |
1373 | ||
1374 | if (waitqueue_active(&ipipe->wait)) | |
1375 | wake_up_interruptible_sync(&ipipe->wait); | |
1376 | kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); | |
1377 | ||
1378 | pipe_wait(ipipe); | |
1379 | } | |
1380 | ||
1381 | mutex_unlock(&ipipe->inode->i_mutex); | |
1382 | mutex_unlock(&opipe->inode->i_mutex); | |
1383 | ||
1384 | if (do_wakeup) { | |
1385 | smp_mb(); | |
1386 | if (waitqueue_active(&opipe->wait)) | |
1387 | wake_up_interruptible(&opipe->wait); | |
1388 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); | |
1389 | } | |
1390 | ||
1391 | return ret; | |
1392 | } | |
1393 | ||
1394 | /* | |
1395 | * This is a tee(1) implementation that works on pipes. It doesn't copy | |
1396 | * any data, it simply references the 'in' pages on the 'out' pipe. | |
1397 | * The 'flags' used are the SPLICE_F_* variants, currently the only | |
1398 | * applicable one is SPLICE_F_NONBLOCK. | |
1399 | */ | |
1400 | static long do_tee(struct file *in, struct file *out, size_t len, | |
1401 | unsigned int flags) | |
1402 | { | |
1403 | struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; | |
1404 | struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; | |
1405 | ||
1406 | /* | |
1407 | * Link ipipe to the two output pipes, consuming as we go along. | |
1408 | */ | |
1409 | if (ipipe && opipe) | |
1410 | return link_pipe(ipipe, opipe, len, flags); | |
1411 | ||
1412 | return -EINVAL; | |
1413 | } | |
1414 | ||
1415 | asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) | |
1416 | { | |
1417 | struct file *in; | |
1418 | int error, fput_in; | |
1419 | ||
1420 | if (unlikely(!len)) | |
1421 | return 0; | |
1422 | ||
1423 | error = -EBADF; | |
1424 | in = fget_light(fdin, &fput_in); | |
1425 | if (in) { | |
1426 | if (in->f_mode & FMODE_READ) { | |
1427 | int fput_out; | |
1428 | struct file *out = fget_light(fdout, &fput_out); | |
1429 | ||
1430 | if (out) { | |
1431 | if (out->f_mode & FMODE_WRITE) | |
1432 | error = do_tee(in, out, len, flags); | |
1433 | fput_light(out, fput_out); | |
1434 | } | |
1435 | } | |
1436 | fput_light(in, fput_in); | |
1437 | } | |
1438 | ||
1439 | return error; | |
1440 | } |