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 | |
1432873a | 81 | buf->flags |= 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); | |
1432873a | 89 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
5274f052 JA |
90 | } |
91 | ||
f84d7519 JA |
92 | static int page_cache_pipe_buf_pin(struct pipe_inode_info *info, |
93 | struct pipe_buffer *buf) | |
5274f052 JA |
94 | { |
95 | struct page *page = buf->page; | |
49d0b21b | 96 | int err; |
5274f052 JA |
97 | |
98 | if (!PageUptodate(page)) { | |
49d0b21b JA |
99 | lock_page(page); |
100 | ||
101 | /* | |
102 | * Page got truncated/unhashed. This will cause a 0-byte | |
73d62d83 | 103 | * splice, if this is the first page. |
49d0b21b JA |
104 | */ |
105 | if (!page->mapping) { | |
106 | err = -ENODATA; | |
107 | goto error; | |
108 | } | |
5274f052 | 109 | |
49d0b21b | 110 | /* |
73d62d83 | 111 | * Uh oh, read-error from disk. |
49d0b21b JA |
112 | */ |
113 | if (!PageUptodate(page)) { | |
114 | err = -EIO; | |
115 | goto error; | |
116 | } | |
117 | ||
118 | /* | |
f84d7519 | 119 | * Page is ok afterall, we are done. |
49d0b21b | 120 | */ |
5274f052 | 121 | unlock_page(page); |
5274f052 JA |
122 | } |
123 | ||
f84d7519 | 124 | return 0; |
49d0b21b JA |
125 | error: |
126 | unlock_page(page); | |
f84d7519 | 127 | return err; |
70524490 JA |
128 | } |
129 | ||
5274f052 JA |
130 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { |
131 | .can_merge = 0, | |
f84d7519 JA |
132 | .map = generic_pipe_buf_map, |
133 | .unmap = generic_pipe_buf_unmap, | |
134 | .pin = page_cache_pipe_buf_pin, | |
5274f052 | 135 | .release = page_cache_pipe_buf_release, |
5abc97aa | 136 | .steal = page_cache_pipe_buf_steal, |
f84d7519 | 137 | .get = generic_pipe_buf_get, |
5274f052 JA |
138 | }; |
139 | ||
912d35f8 JA |
140 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
141 | struct pipe_buffer *buf) | |
142 | { | |
7afa6fd0 JA |
143 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
144 | return 1; | |
145 | ||
1432873a | 146 | buf->flags |= PIPE_BUF_FLAG_LRU; |
330ab716 | 147 | return generic_pipe_buf_steal(pipe, buf); |
912d35f8 JA |
148 | } |
149 | ||
150 | static struct pipe_buf_operations user_page_pipe_buf_ops = { | |
151 | .can_merge = 0, | |
f84d7519 JA |
152 | .map = generic_pipe_buf_map, |
153 | .unmap = generic_pipe_buf_unmap, | |
154 | .pin = generic_pipe_buf_pin, | |
912d35f8 JA |
155 | .release = page_cache_pipe_buf_release, |
156 | .steal = user_page_pipe_buf_steal, | |
f84d7519 | 157 | .get = generic_pipe_buf_get, |
912d35f8 JA |
158 | }; |
159 | ||
83f9135b JA |
160 | /* |
161 | * Pipe output worker. This sets up our pipe format with the page cache | |
162 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). | |
163 | */ | |
00522fb4 JA |
164 | static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
165 | struct splice_pipe_desc *spd) | |
5274f052 | 166 | { |
912d35f8 | 167 | int ret, do_wakeup, page_nr; |
5274f052 JA |
168 | |
169 | ret = 0; | |
170 | do_wakeup = 0; | |
912d35f8 | 171 | page_nr = 0; |
5274f052 | 172 | |
3a326a2c IM |
173 | if (pipe->inode) |
174 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 175 | |
5274f052 | 176 | for (;;) { |
3a326a2c | 177 | if (!pipe->readers) { |
5274f052 JA |
178 | send_sig(SIGPIPE, current, 0); |
179 | if (!ret) | |
180 | ret = -EPIPE; | |
181 | break; | |
182 | } | |
183 | ||
6f767b04 JA |
184 | if (pipe->nrbufs < PIPE_BUFFERS) { |
185 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); | |
3a326a2c | 186 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
5274f052 | 187 | |
912d35f8 JA |
188 | buf->page = spd->pages[page_nr]; |
189 | buf->offset = spd->partial[page_nr].offset; | |
190 | buf->len = spd->partial[page_nr].len; | |
191 | buf->ops = spd->ops; | |
7afa6fd0 JA |
192 | if (spd->flags & SPLICE_F_GIFT) |
193 | buf->flags |= PIPE_BUF_FLAG_GIFT; | |
194 | ||
6f767b04 | 195 | pipe->nrbufs++; |
912d35f8 JA |
196 | page_nr++; |
197 | ret += buf->len; | |
198 | ||
6f767b04 JA |
199 | if (pipe->inode) |
200 | do_wakeup = 1; | |
5274f052 | 201 | |
912d35f8 | 202 | if (!--spd->nr_pages) |
5274f052 | 203 | break; |
6f767b04 | 204 | if (pipe->nrbufs < PIPE_BUFFERS) |
5274f052 JA |
205 | continue; |
206 | ||
207 | break; | |
208 | } | |
209 | ||
912d35f8 | 210 | if (spd->flags & SPLICE_F_NONBLOCK) { |
29e35094 LT |
211 | if (!ret) |
212 | ret = -EAGAIN; | |
213 | break; | |
214 | } | |
215 | ||
5274f052 JA |
216 | if (signal_pending(current)) { |
217 | if (!ret) | |
218 | ret = -ERESTARTSYS; | |
219 | break; | |
220 | } | |
221 | ||
222 | if (do_wakeup) { | |
c0bd1f65 | 223 | smp_mb(); |
3a326a2c IM |
224 | if (waitqueue_active(&pipe->wait)) |
225 | wake_up_interruptible_sync(&pipe->wait); | |
226 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
227 | do_wakeup = 0; |
228 | } | |
229 | ||
3a326a2c IM |
230 | pipe->waiting_writers++; |
231 | pipe_wait(pipe); | |
232 | pipe->waiting_writers--; | |
5274f052 JA |
233 | } |
234 | ||
3a326a2c IM |
235 | if (pipe->inode) |
236 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
237 | |
238 | if (do_wakeup) { | |
c0bd1f65 | 239 | smp_mb(); |
3a326a2c IM |
240 | if (waitqueue_active(&pipe->wait)) |
241 | wake_up_interruptible(&pipe->wait); | |
242 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
243 | } |
244 | ||
912d35f8 JA |
245 | while (page_nr < spd->nr_pages) |
246 | page_cache_release(spd->pages[page_nr++]); | |
5274f052 JA |
247 | |
248 | return ret; | |
249 | } | |
250 | ||
3a326a2c | 251 | static int |
cbb7e577 JA |
252 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
253 | struct pipe_inode_info *pipe, size_t len, | |
254 | unsigned int flags) | |
5274f052 JA |
255 | { |
256 | struct address_space *mapping = in->f_mapping; | |
912d35f8 | 257 | unsigned int loff, nr_pages; |
16c523dd | 258 | struct page *pages[PIPE_BUFFERS]; |
912d35f8 | 259 | struct partial_page partial[PIPE_BUFFERS]; |
5274f052 | 260 | struct page *page; |
91ad66ef JA |
261 | pgoff_t index, end_index; |
262 | loff_t isize; | |
912d35f8 | 263 | size_t total_len; |
eb20796b | 264 | int error, page_nr; |
912d35f8 JA |
265 | struct splice_pipe_desc spd = { |
266 | .pages = pages, | |
267 | .partial = partial, | |
268 | .flags = flags, | |
269 | .ops = &page_cache_pipe_buf_ops, | |
270 | }; | |
5274f052 | 271 | |
cbb7e577 | 272 | index = *ppos >> PAGE_CACHE_SHIFT; |
912d35f8 JA |
273 | loff = *ppos & ~PAGE_CACHE_MASK; |
274 | nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
5274f052 JA |
275 | |
276 | if (nr_pages > PIPE_BUFFERS) | |
277 | nr_pages = PIPE_BUFFERS; | |
278 | ||
279 | /* | |
73d62d83 | 280 | * Initiate read-ahead on this page range. however, don't call into |
0b749ce3 JA |
281 | * read-ahead if this is a non-zero offset (we are likely doing small |
282 | * chunk splice and the page is already there) for a single page. | |
5274f052 | 283 | */ |
eb645a24 JA |
284 | if (!loff || nr_pages > 1) |
285 | page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); | |
5274f052 | 286 | |
5274f052 | 287 | /* |
73d62d83 | 288 | * Now fill in the holes: |
5274f052 | 289 | */ |
7480a904 | 290 | error = 0; |
912d35f8 | 291 | total_len = 0; |
82aa5d61 | 292 | |
eb20796b JA |
293 | /* |
294 | * Lookup the (hopefully) full range of pages we need. | |
295 | */ | |
296 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); | |
82aa5d61 | 297 | |
eb20796b JA |
298 | /* |
299 | * If find_get_pages_contig() returned fewer pages than we needed, | |
300 | * allocate the rest. | |
301 | */ | |
302 | index += spd.nr_pages; | |
303 | while (spd.nr_pages < nr_pages) { | |
82aa5d61 | 304 | /* |
eb20796b JA |
305 | * Page could be there, find_get_pages_contig() breaks on |
306 | * the first hole. | |
5274f052 | 307 | */ |
7480a904 JA |
308 | page = find_get_page(mapping, index); |
309 | if (!page) { | |
e27dedd8 JA |
310 | /* |
311 | * Make sure the read-ahead engine is notified | |
312 | * about this failure. | |
313 | */ | |
314 | handle_ra_miss(mapping, &in->f_ra, index); | |
315 | ||
7480a904 | 316 | /* |
eb20796b | 317 | * page didn't exist, allocate one. |
7480a904 JA |
318 | */ |
319 | page = page_cache_alloc_cold(mapping); | |
320 | if (!page) | |
321 | break; | |
322 | ||
323 | error = add_to_page_cache_lru(page, mapping, index, | |
eb20796b | 324 | mapping_gfp_mask(mapping)); |
7480a904 JA |
325 | if (unlikely(error)) { |
326 | page_cache_release(page); | |
327 | break; | |
328 | } | |
eb20796b JA |
329 | /* |
330 | * add_to_page_cache() locks the page, unlock it | |
331 | * to avoid convoluting the logic below even more. | |
332 | */ | |
333 | unlock_page(page); | |
7480a904 JA |
334 | } |
335 | ||
eb20796b JA |
336 | pages[spd.nr_pages++] = page; |
337 | index++; | |
338 | } | |
339 | ||
340 | /* | |
341 | * Now loop over the map and see if we need to start IO on any | |
342 | * pages, fill in the partial map, etc. | |
343 | */ | |
344 | index = *ppos >> PAGE_CACHE_SHIFT; | |
345 | nr_pages = spd.nr_pages; | |
346 | spd.nr_pages = 0; | |
347 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { | |
348 | unsigned int this_len; | |
349 | ||
350 | if (!len) | |
351 | break; | |
352 | ||
353 | /* | |
354 | * this_len is the max we'll use from this page | |
355 | */ | |
356 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); | |
357 | page = pages[page_nr]; | |
358 | ||
7480a904 JA |
359 | /* |
360 | * If the page isn't uptodate, we may need to start io on it | |
361 | */ | |
362 | if (!PageUptodate(page)) { | |
c4f895cb JA |
363 | /* |
364 | * If in nonblock mode then dont block on waiting | |
365 | * for an in-flight io page | |
366 | */ | |
367 | if (flags & SPLICE_F_NONBLOCK) | |
368 | break; | |
369 | ||
7480a904 JA |
370 | lock_page(page); |
371 | ||
372 | /* | |
373 | * page was truncated, stop here. if this isn't the | |
374 | * first page, we'll just complete what we already | |
375 | * added | |
376 | */ | |
377 | if (!page->mapping) { | |
378 | unlock_page(page); | |
7480a904 JA |
379 | break; |
380 | } | |
381 | /* | |
382 | * page was already under io and is now done, great | |
383 | */ | |
384 | if (PageUptodate(page)) { | |
385 | unlock_page(page); | |
386 | goto fill_it; | |
387 | } | |
5274f052 | 388 | |
7480a904 JA |
389 | /* |
390 | * need to read in the page | |
391 | */ | |
392 | error = mapping->a_ops->readpage(in, page); | |
5274f052 | 393 | if (unlikely(error)) { |
eb20796b JA |
394 | /* |
395 | * We really should re-lookup the page here, | |
396 | * but it complicates things a lot. Instead | |
397 | * lets just do what we already stored, and | |
398 | * we'll get it the next time we are called. | |
399 | */ | |
7480a904 | 400 | if (error == AOP_TRUNCATED_PAGE) |
eb20796b JA |
401 | error = 0; |
402 | ||
5274f052 JA |
403 | break; |
404 | } | |
91ad66ef JA |
405 | |
406 | /* | |
407 | * i_size must be checked after ->readpage(). | |
408 | */ | |
409 | isize = i_size_read(mapping->host); | |
410 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; | |
eb20796b | 411 | if (unlikely(!isize || index > end_index)) |
91ad66ef | 412 | break; |
91ad66ef JA |
413 | |
414 | /* | |
415 | * if this is the last page, see if we need to shrink | |
416 | * the length and stop | |
417 | */ | |
418 | if (end_index == index) { | |
419 | loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); | |
eb20796b | 420 | if (total_len + loff > isize) |
91ad66ef | 421 | break; |
91ad66ef JA |
422 | /* |
423 | * force quit after adding this page | |
424 | */ | |
eb20796b | 425 | len = this_len; |
82aa5d61 | 426 | this_len = min(this_len, loff); |
912d35f8 | 427 | loff = 0; |
91ad66ef | 428 | } |
5274f052 | 429 | } |
7480a904 | 430 | fill_it: |
eb20796b JA |
431 | partial[page_nr].offset = loff; |
432 | partial[page_nr].len = this_len; | |
82aa5d61 | 433 | len -= this_len; |
912d35f8 | 434 | total_len += this_len; |
91ad66ef | 435 | loff = 0; |
eb20796b JA |
436 | spd.nr_pages++; |
437 | index++; | |
5274f052 JA |
438 | } |
439 | ||
eb20796b JA |
440 | /* |
441 | * Release any pages at the end, if we quit early. 'i' is how far | |
442 | * we got, 'nr_pages' is how many pages are in the map. | |
443 | */ | |
444 | while (page_nr < nr_pages) | |
445 | page_cache_release(pages[page_nr++]); | |
446 | ||
912d35f8 | 447 | if (spd.nr_pages) |
00522fb4 | 448 | return splice_to_pipe(pipe, &spd); |
5274f052 | 449 | |
7480a904 | 450 | return error; |
5274f052 JA |
451 | } |
452 | ||
83f9135b JA |
453 | /** |
454 | * generic_file_splice_read - splice data from file to a pipe | |
455 | * @in: file to splice from | |
456 | * @pipe: pipe to splice to | |
457 | * @len: number of bytes to splice | |
458 | * @flags: splice modifier flags | |
459 | * | |
460 | * Will read pages from given file and fill them into a pipe. | |
83f9135b | 461 | */ |
cbb7e577 JA |
462 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
463 | struct pipe_inode_info *pipe, size_t len, | |
464 | unsigned int flags) | |
5274f052 JA |
465 | { |
466 | ssize_t spliced; | |
467 | int ret; | |
468 | ||
469 | ret = 0; | |
470 | spliced = 0; | |
3a326a2c | 471 | |
5274f052 | 472 | while (len) { |
cbb7e577 | 473 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
5274f052 | 474 | |
c4f895cb | 475 | if (ret < 0) |
5274f052 | 476 | break; |
c4f895cb JA |
477 | else if (!ret) { |
478 | if (spliced) | |
479 | break; | |
480 | if (flags & SPLICE_F_NONBLOCK) { | |
481 | ret = -EAGAIN; | |
482 | break; | |
483 | } | |
484 | } | |
5274f052 | 485 | |
cbb7e577 | 486 | *ppos += ret; |
5274f052 JA |
487 | len -= ret; |
488 | spliced += ret; | |
489 | } | |
490 | ||
491 | if (spliced) | |
492 | return spliced; | |
493 | ||
494 | return ret; | |
495 | } | |
496 | ||
059a8f37 JA |
497 | EXPORT_SYMBOL(generic_file_splice_read); |
498 | ||
5274f052 | 499 | /* |
4f6f0bd2 | 500 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
016b661e | 501 | * using sendpage(). Return the number of bytes sent. |
5274f052 JA |
502 | */ |
503 | static int pipe_to_sendpage(struct pipe_inode_info *info, | |
504 | struct pipe_buffer *buf, struct splice_desc *sd) | |
505 | { | |
506 | struct file *file = sd->file; | |
507 | loff_t pos = sd->pos; | |
f84d7519 | 508 | int ret, more; |
5274f052 | 509 | |
f84d7519 JA |
510 | ret = buf->ops->pin(info, buf); |
511 | if (!ret) { | |
512 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; | |
5274f052 | 513 | |
f84d7519 JA |
514 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
515 | sd->len, &pos, more); | |
516 | } | |
5274f052 | 517 | |
016b661e | 518 | return ret; |
5274f052 JA |
519 | } |
520 | ||
521 | /* | |
522 | * This is a little more tricky than the file -> pipe splicing. There are | |
523 | * basically three cases: | |
524 | * | |
525 | * - Destination page already exists in the address space and there | |
526 | * are users of it. For that case we have no other option that | |
527 | * copying the data. Tough luck. | |
528 | * - Destination page already exists in the address space, but there | |
529 | * are no users of it. Make sure it's uptodate, then drop it. Fall | |
530 | * through to last case. | |
531 | * - Destination page does not exist, we can add the pipe page to | |
532 | * the page cache and avoid the copy. | |
533 | * | |
83f9135b JA |
534 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
535 | * sd->flags), we attempt to migrate pages from the pipe to the output | |
536 | * file address space page cache. This is possible if no one else has | |
537 | * the pipe page referenced outside of the pipe and page cache. If | |
538 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create | |
539 | * a new page in the output file page cache and fill/dirty that. | |
5274f052 JA |
540 | */ |
541 | static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, | |
542 | struct splice_desc *sd) | |
543 | { | |
544 | struct file *file = sd->file; | |
545 | struct address_space *mapping = file->f_mapping; | |
3e7ee3e7 | 546 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
016b661e | 547 | unsigned int offset, this_len; |
5274f052 | 548 | struct page *page; |
5274f052 | 549 | pgoff_t index; |
3e7ee3e7 | 550 | int ret; |
5274f052 JA |
551 | |
552 | /* | |
49d0b21b | 553 | * make sure the data in this buffer is uptodate |
5274f052 | 554 | */ |
f84d7519 JA |
555 | ret = buf->ops->pin(info, buf); |
556 | if (unlikely(ret)) | |
557 | return ret; | |
5274f052 JA |
558 | |
559 | index = sd->pos >> PAGE_CACHE_SHIFT; | |
560 | offset = sd->pos & ~PAGE_CACHE_MASK; | |
561 | ||
016b661e JA |
562 | this_len = sd->len; |
563 | if (this_len + offset > PAGE_CACHE_SIZE) | |
564 | this_len = PAGE_CACHE_SIZE - offset; | |
565 | ||
5274f052 | 566 | /* |
0568b409 JA |
567 | * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full |
568 | * page. | |
5274f052 | 569 | */ |
0568b409 | 570 | if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) { |
83f9135b | 571 | /* |
1432873a JA |
572 | * If steal succeeds, buf->page is now pruned from the |
573 | * pagecache and we can reuse it. The page will also be | |
574 | * locked on successful return. | |
83f9135b | 575 | */ |
5abc97aa JA |
576 | if (buf->ops->steal(info, buf)) |
577 | goto find_page; | |
578 | ||
579 | page = buf->page; | |
46e678c9 JA |
580 | if (add_to_page_cache(page, mapping, index, gfp_mask)) { |
581 | unlock_page(page); | |
5abc97aa | 582 | goto find_page; |
46e678c9 | 583 | } |
1432873a JA |
584 | |
585 | page_cache_get(page); | |
586 | ||
587 | if (!(buf->flags & PIPE_BUF_FLAG_LRU)) | |
588 | lru_cache_add(page); | |
5abc97aa JA |
589 | } else { |
590 | find_page: | |
9e0267c2 JA |
591 | page = find_lock_page(mapping, index); |
592 | if (!page) { | |
593 | ret = -ENOMEM; | |
594 | page = page_cache_alloc_cold(mapping); | |
595 | if (unlikely(!page)) | |
596 | goto out_nomem; | |
597 | ||
598 | /* | |
599 | * This will also lock the page | |
600 | */ | |
601 | ret = add_to_page_cache_lru(page, mapping, index, | |
602 | gfp_mask); | |
603 | if (unlikely(ret)) | |
604 | goto out; | |
605 | } | |
5abc97aa JA |
606 | |
607 | /* | |
9e0267c2 JA |
608 | * We get here with the page locked. If the page is also |
609 | * uptodate, we don't need to do more. If it isn't, we | |
610 | * may need to bring it in if we are not going to overwrite | |
611 | * the full page. | |
5abc97aa JA |
612 | */ |
613 | if (!PageUptodate(page)) { | |
016b661e | 614 | if (this_len < PAGE_CACHE_SIZE) { |
5abc97aa JA |
615 | ret = mapping->a_ops->readpage(file, page); |
616 | if (unlikely(ret)) | |
617 | goto out; | |
618 | ||
619 | lock_page(page); | |
620 | ||
621 | if (!PageUptodate(page)) { | |
622 | /* | |
73d62d83 | 623 | * Page got invalidated, repeat. |
5abc97aa JA |
624 | */ |
625 | if (!page->mapping) { | |
626 | unlock_page(page); | |
627 | page_cache_release(page); | |
628 | goto find_page; | |
629 | } | |
630 | ret = -EIO; | |
631 | goto out; | |
5274f052 | 632 | } |
9e0267c2 | 633 | } else |
5abc97aa | 634 | SetPageUptodate(page); |
5274f052 JA |
635 | } |
636 | } | |
637 | ||
016b661e | 638 | ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); |
bfc4ee39 JA |
639 | if (unlikely(ret)) { |
640 | loff_t isize = i_size_read(mapping->host); | |
641 | ||
642 | if (ret != AOP_TRUNCATED_PAGE) | |
643 | unlock_page(page); | |
4f6f0bd2 | 644 | page_cache_release(page); |
bfc4ee39 JA |
645 | if (ret == AOP_TRUNCATED_PAGE) |
646 | goto find_page; | |
647 | ||
648 | /* | |
649 | * prepare_write() may have instantiated a few blocks | |
650 | * outside i_size. Trim these off again. | |
651 | */ | |
652 | if (sd->pos + this_len > isize) | |
653 | vmtruncate(mapping->host, isize); | |
654 | ||
5274f052 | 655 | goto out; |
bfc4ee39 | 656 | } |
5274f052 | 657 | |
0568b409 | 658 | if (buf->page != page) { |
f84d7519 JA |
659 | /* |
660 | * Careful, ->map() uses KM_USER0! | |
661 | */ | |
f6762b7a | 662 | char *src = buf->ops->map(info, buf, 1); |
f84d7519 | 663 | char *dst = kmap_atomic(page, KM_USER1); |
5abc97aa | 664 | |
016b661e | 665 | memcpy(dst + offset, src + buf->offset, this_len); |
5abc97aa | 666 | flush_dcache_page(page); |
f84d7519 | 667 | kunmap_atomic(dst, KM_USER1); |
f6762b7a | 668 | buf->ops->unmap(info, buf, src); |
5abc97aa | 669 | } |
5274f052 | 670 | |
016b661e | 671 | ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); |
0568b409 JA |
672 | if (!ret) { |
673 | /* | |
674 | * Return the number of bytes written and mark page as | |
675 | * accessed, we are now done! | |
676 | */ | |
677 | ret = this_len; | |
678 | mark_page_accessed(page); | |
679 | balance_dirty_pages_ratelimited(mapping); | |
680 | } else if (ret == AOP_TRUNCATED_PAGE) { | |
4f6f0bd2 JA |
681 | page_cache_release(page); |
682 | goto find_page; | |
0568b409 | 683 | } |
5274f052 | 684 | out: |
0568b409 | 685 | page_cache_release(page); |
9e0267c2 | 686 | unlock_page(page); |
9aefe431 | 687 | out_nomem: |
5274f052 JA |
688 | return ret; |
689 | } | |
690 | ||
83f9135b JA |
691 | /* |
692 | * Pipe input worker. Most of this logic works like a regular pipe, the | |
693 | * key here is the 'actor' worker passed in that actually moves the data | |
694 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. | |
695 | */ | |
00522fb4 JA |
696 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
697 | loff_t *ppos, size_t len, unsigned int flags, | |
698 | splice_actor *actor) | |
5274f052 | 699 | { |
5274f052 JA |
700 | int ret, do_wakeup, err; |
701 | struct splice_desc sd; | |
702 | ||
703 | ret = 0; | |
704 | do_wakeup = 0; | |
705 | ||
706 | sd.total_len = len; | |
707 | sd.flags = flags; | |
708 | sd.file = out; | |
cbb7e577 | 709 | sd.pos = *ppos; |
5274f052 | 710 | |
3a326a2c IM |
711 | if (pipe->inode) |
712 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 713 | |
5274f052 | 714 | for (;;) { |
6f767b04 JA |
715 | if (pipe->nrbufs) { |
716 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; | |
5274f052 JA |
717 | struct pipe_buf_operations *ops = buf->ops; |
718 | ||
719 | sd.len = buf->len; | |
720 | if (sd.len > sd.total_len) | |
721 | sd.len = sd.total_len; | |
722 | ||
3a326a2c | 723 | err = actor(pipe, buf, &sd); |
016b661e | 724 | if (err <= 0) { |
5274f052 JA |
725 | if (!ret && err != -ENODATA) |
726 | ret = err; | |
727 | ||
728 | break; | |
729 | } | |
730 | ||
016b661e JA |
731 | ret += err; |
732 | buf->offset += err; | |
733 | buf->len -= err; | |
734 | ||
735 | sd.len -= err; | |
736 | sd.pos += err; | |
737 | sd.total_len -= err; | |
738 | if (sd.len) | |
739 | continue; | |
73d62d83 | 740 | |
5274f052 JA |
741 | if (!buf->len) { |
742 | buf->ops = NULL; | |
3a326a2c | 743 | ops->release(pipe, buf); |
6f767b04 JA |
744 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
745 | pipe->nrbufs--; | |
746 | if (pipe->inode) | |
747 | do_wakeup = 1; | |
5274f052 JA |
748 | } |
749 | ||
5274f052 JA |
750 | if (!sd.total_len) |
751 | break; | |
752 | } | |
753 | ||
6f767b04 | 754 | if (pipe->nrbufs) |
5274f052 | 755 | continue; |
3a326a2c | 756 | if (!pipe->writers) |
5274f052 | 757 | break; |
3a326a2c | 758 | if (!pipe->waiting_writers) { |
5274f052 JA |
759 | if (ret) |
760 | break; | |
761 | } | |
762 | ||
29e35094 LT |
763 | if (flags & SPLICE_F_NONBLOCK) { |
764 | if (!ret) | |
765 | ret = -EAGAIN; | |
766 | break; | |
767 | } | |
768 | ||
5274f052 JA |
769 | if (signal_pending(current)) { |
770 | if (!ret) | |
771 | ret = -ERESTARTSYS; | |
772 | break; | |
773 | } | |
774 | ||
775 | if (do_wakeup) { | |
c0bd1f65 | 776 | smp_mb(); |
3a326a2c IM |
777 | if (waitqueue_active(&pipe->wait)) |
778 | wake_up_interruptible_sync(&pipe->wait); | |
779 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
780 | do_wakeup = 0; |
781 | } | |
782 | ||
3a326a2c | 783 | pipe_wait(pipe); |
5274f052 JA |
784 | } |
785 | ||
3a326a2c IM |
786 | if (pipe->inode) |
787 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
788 | |
789 | if (do_wakeup) { | |
c0bd1f65 | 790 | smp_mb(); |
3a326a2c IM |
791 | if (waitqueue_active(&pipe->wait)) |
792 | wake_up_interruptible(&pipe->wait); | |
793 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
794 | } |
795 | ||
5274f052 | 796 | return ret; |
5274f052 JA |
797 | } |
798 | ||
83f9135b JA |
799 | /** |
800 | * generic_file_splice_write - splice data from a pipe to a file | |
3a326a2c | 801 | * @pipe: pipe info |
83f9135b JA |
802 | * @out: file to write to |
803 | * @len: number of bytes to splice | |
804 | * @flags: splice modifier flags | |
805 | * | |
806 | * Will either move or copy pages (determined by @flags options) from | |
807 | * the given pipe inode to the given file. | |
808 | * | |
809 | */ | |
3a326a2c IM |
810 | ssize_t |
811 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, | |
cbb7e577 | 812 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 813 | { |
4f6f0bd2 | 814 | struct address_space *mapping = out->f_mapping; |
3a326a2c IM |
815 | ssize_t ret; |
816 | ||
00522fb4 | 817 | ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
a4514ebd | 818 | if (ret > 0) { |
4f6f0bd2 | 819 | struct inode *inode = mapping->host; |
4f6f0bd2 | 820 | |
a4514ebd JA |
821 | *ppos += ret; |
822 | ||
823 | /* | |
824 | * If file or inode is SYNC and we actually wrote some data, | |
825 | * sync it. | |
826 | */ | |
827 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { | |
828 | int err; | |
829 | ||
830 | mutex_lock(&inode->i_mutex); | |
831 | err = generic_osync_inode(inode, mapping, | |
832 | OSYNC_METADATA|OSYNC_DATA); | |
833 | mutex_unlock(&inode->i_mutex); | |
4f6f0bd2 | 834 | |
a4514ebd JA |
835 | if (err) |
836 | ret = err; | |
837 | } | |
4f6f0bd2 JA |
838 | } |
839 | ||
840 | return ret; | |
5274f052 JA |
841 | } |
842 | ||
059a8f37 JA |
843 | EXPORT_SYMBOL(generic_file_splice_write); |
844 | ||
83f9135b JA |
845 | /** |
846 | * generic_splice_sendpage - splice data from a pipe to a socket | |
847 | * @inode: pipe inode | |
848 | * @out: socket to write to | |
849 | * @len: number of bytes to splice | |
850 | * @flags: splice modifier flags | |
851 | * | |
852 | * Will send @len bytes from the pipe to a network socket. No data copying | |
853 | * is involved. | |
854 | * | |
855 | */ | |
3a326a2c | 856 | ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 857 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 858 | { |
00522fb4 | 859 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
5274f052 JA |
860 | } |
861 | ||
059a8f37 | 862 | EXPORT_SYMBOL(generic_splice_sendpage); |
a0f06780 | 863 | |
83f9135b JA |
864 | /* |
865 | * Attempt to initiate a splice from pipe to file. | |
866 | */ | |
3a326a2c | 867 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 868 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 869 | { |
5274f052 JA |
870 | int ret; |
871 | ||
49570e9b | 872 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
5274f052 JA |
873 | return -EINVAL; |
874 | ||
49570e9b | 875 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
5274f052 JA |
876 | return -EBADF; |
877 | ||
cbb7e577 | 878 | ret = rw_verify_area(WRITE, out, ppos, len); |
5274f052 JA |
879 | if (unlikely(ret < 0)) |
880 | return ret; | |
881 | ||
cbb7e577 | 882 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
5274f052 JA |
883 | } |
884 | ||
83f9135b JA |
885 | /* |
886 | * Attempt to initiate a splice from a file to a pipe. | |
887 | */ | |
cbb7e577 JA |
888 | static long do_splice_to(struct file *in, loff_t *ppos, |
889 | struct pipe_inode_info *pipe, size_t len, | |
890 | unsigned int flags) | |
5274f052 | 891 | { |
cbb7e577 | 892 | loff_t isize, left; |
5274f052 JA |
893 | int ret; |
894 | ||
49570e9b | 895 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
5274f052 JA |
896 | return -EINVAL; |
897 | ||
49570e9b | 898 | if (unlikely(!(in->f_mode & FMODE_READ))) |
5274f052 JA |
899 | return -EBADF; |
900 | ||
cbb7e577 | 901 | ret = rw_verify_area(READ, in, ppos, len); |
5274f052 JA |
902 | if (unlikely(ret < 0)) |
903 | return ret; | |
904 | ||
905 | isize = i_size_read(in->f_mapping->host); | |
cbb7e577 | 906 | if (unlikely(*ppos >= isize)) |
5274f052 JA |
907 | return 0; |
908 | ||
cbb7e577 | 909 | left = isize - *ppos; |
49570e9b | 910 | if (unlikely(left < len)) |
5274f052 JA |
911 | len = left; |
912 | ||
cbb7e577 | 913 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
5274f052 JA |
914 | } |
915 | ||
cbb7e577 JA |
916 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
917 | size_t len, unsigned int flags) | |
b92ce558 JA |
918 | { |
919 | struct pipe_inode_info *pipe; | |
920 | long ret, bytes; | |
cbb7e577 | 921 | loff_t out_off; |
b92ce558 JA |
922 | umode_t i_mode; |
923 | int i; | |
924 | ||
925 | /* | |
926 | * We require the input being a regular file, as we don't want to | |
927 | * randomly drop data for eg socket -> socket splicing. Use the | |
928 | * piped splicing for that! | |
929 | */ | |
930 | i_mode = in->f_dentry->d_inode->i_mode; | |
931 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) | |
932 | return -EINVAL; | |
933 | ||
934 | /* | |
935 | * neither in nor out is a pipe, setup an internal pipe attached to | |
936 | * 'out' and transfer the wanted data from 'in' to 'out' through that | |
937 | */ | |
938 | pipe = current->splice_pipe; | |
49570e9b | 939 | if (unlikely(!pipe)) { |
b92ce558 JA |
940 | pipe = alloc_pipe_info(NULL); |
941 | if (!pipe) | |
942 | return -ENOMEM; | |
943 | ||
944 | /* | |
945 | * We don't have an immediate reader, but we'll read the stuff | |
00522fb4 | 946 | * out of the pipe right after the splice_to_pipe(). So set |
b92ce558 JA |
947 | * PIPE_READERS appropriately. |
948 | */ | |
949 | pipe->readers = 1; | |
950 | ||
951 | current->splice_pipe = pipe; | |
952 | } | |
953 | ||
954 | /* | |
73d62d83 | 955 | * Do the splice. |
b92ce558 JA |
956 | */ |
957 | ret = 0; | |
958 | bytes = 0; | |
cbb7e577 | 959 | out_off = 0; |
b92ce558 JA |
960 | |
961 | while (len) { | |
962 | size_t read_len, max_read_len; | |
963 | ||
964 | /* | |
965 | * Do at most PIPE_BUFFERS pages worth of transfer: | |
966 | */ | |
967 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); | |
968 | ||
cbb7e577 | 969 | ret = do_splice_to(in, ppos, pipe, max_read_len, flags); |
b92ce558 JA |
970 | if (unlikely(ret < 0)) |
971 | goto out_release; | |
972 | ||
973 | read_len = ret; | |
974 | ||
975 | /* | |
976 | * NOTE: nonblocking mode only applies to the input. We | |
977 | * must not do the output in nonblocking mode as then we | |
978 | * could get stuck data in the internal pipe: | |
979 | */ | |
cbb7e577 | 980 | ret = do_splice_from(pipe, out, &out_off, read_len, |
b92ce558 JA |
981 | flags & ~SPLICE_F_NONBLOCK); |
982 | if (unlikely(ret < 0)) | |
983 | goto out_release; | |
984 | ||
985 | bytes += ret; | |
986 | len -= ret; | |
987 | ||
988 | /* | |
989 | * In nonblocking mode, if we got back a short read then | |
990 | * that was due to either an IO error or due to the | |
991 | * pagecache entry not being there. In the IO error case | |
992 | * the _next_ splice attempt will produce a clean IO error | |
993 | * return value (not a short read), so in both cases it's | |
994 | * correct to break out of the loop here: | |
995 | */ | |
996 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) | |
997 | break; | |
998 | } | |
999 | ||
1000 | pipe->nrbufs = pipe->curbuf = 0; | |
1001 | ||
1002 | return bytes; | |
1003 | ||
1004 | out_release: | |
1005 | /* | |
1006 | * If we did an incomplete transfer we must release | |
1007 | * the pipe buffers in question: | |
1008 | */ | |
1009 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
1010 | struct pipe_buffer *buf = pipe->bufs + i; | |
1011 | ||
1012 | if (buf->ops) { | |
1013 | buf->ops->release(pipe, buf); | |
1014 | buf->ops = NULL; | |
1015 | } | |
1016 | } | |
1017 | pipe->nrbufs = pipe->curbuf = 0; | |
1018 | ||
1019 | /* | |
1020 | * If we transferred some data, return the number of bytes: | |
1021 | */ | |
1022 | if (bytes > 0) | |
1023 | return bytes; | |
1024 | ||
1025 | return ret; | |
1026 | } | |
1027 | ||
1028 | EXPORT_SYMBOL(do_splice_direct); | |
1029 | ||
83f9135b JA |
1030 | /* |
1031 | * Determine where to splice to/from. | |
1032 | */ | |
529565dc IM |
1033 | static long do_splice(struct file *in, loff_t __user *off_in, |
1034 | struct file *out, loff_t __user *off_out, | |
1035 | size_t len, unsigned int flags) | |
5274f052 | 1036 | { |
3a326a2c | 1037 | struct pipe_inode_info *pipe; |
cbb7e577 | 1038 | loff_t offset, *off; |
a4514ebd | 1039 | long ret; |
5274f052 | 1040 | |
3a326a2c | 1041 | pipe = in->f_dentry->d_inode->i_pipe; |
529565dc IM |
1042 | if (pipe) { |
1043 | if (off_in) | |
1044 | return -ESPIPE; | |
b92ce558 JA |
1045 | if (off_out) { |
1046 | if (out->f_op->llseek == no_llseek) | |
1047 | return -EINVAL; | |
cbb7e577 | 1048 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
b92ce558 | 1049 | return -EFAULT; |
cbb7e577 JA |
1050 | off = &offset; |
1051 | } else | |
1052 | off = &out->f_pos; | |
529565dc | 1053 | |
a4514ebd JA |
1054 | ret = do_splice_from(pipe, out, off, len, flags); |
1055 | ||
1056 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) | |
1057 | ret = -EFAULT; | |
1058 | ||
1059 | return ret; | |
529565dc | 1060 | } |
5274f052 | 1061 | |
3a326a2c | 1062 | pipe = out->f_dentry->d_inode->i_pipe; |
529565dc IM |
1063 | if (pipe) { |
1064 | if (off_out) | |
1065 | return -ESPIPE; | |
b92ce558 JA |
1066 | if (off_in) { |
1067 | if (in->f_op->llseek == no_llseek) | |
1068 | return -EINVAL; | |
cbb7e577 | 1069 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
b92ce558 | 1070 | return -EFAULT; |
cbb7e577 JA |
1071 | off = &offset; |
1072 | } else | |
1073 | off = &in->f_pos; | |
529565dc | 1074 | |
a4514ebd JA |
1075 | ret = do_splice_to(in, off, pipe, len, flags); |
1076 | ||
1077 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) | |
1078 | ret = -EFAULT; | |
1079 | ||
1080 | return ret; | |
529565dc | 1081 | } |
5274f052 JA |
1082 | |
1083 | return -EINVAL; | |
1084 | } | |
1085 | ||
912d35f8 JA |
1086 | /* |
1087 | * Map an iov into an array of pages and offset/length tupples. With the | |
1088 | * partial_page structure, we can map several non-contiguous ranges into | |
1089 | * our ones pages[] map instead of splitting that operation into pieces. | |
1090 | * Could easily be exported as a generic helper for other users, in which | |
1091 | * case one would probably want to add a 'max_nr_pages' parameter as well. | |
1092 | */ | |
1093 | static int get_iovec_page_array(const struct iovec __user *iov, | |
1094 | unsigned int nr_vecs, struct page **pages, | |
7afa6fd0 | 1095 | struct partial_page *partial, int aligned) |
912d35f8 JA |
1096 | { |
1097 | int buffers = 0, error = 0; | |
1098 | ||
1099 | /* | |
1100 | * It's ok to take the mmap_sem for reading, even | |
1101 | * across a "get_user()". | |
1102 | */ | |
1103 | down_read(¤t->mm->mmap_sem); | |
1104 | ||
1105 | while (nr_vecs) { | |
1106 | unsigned long off, npages; | |
1107 | void __user *base; | |
1108 | size_t len; | |
1109 | int i; | |
1110 | ||
1111 | /* | |
1112 | * Get user address base and length for this iovec. | |
1113 | */ | |
1114 | error = get_user(base, &iov->iov_base); | |
1115 | if (unlikely(error)) | |
1116 | break; | |
1117 | error = get_user(len, &iov->iov_len); | |
1118 | if (unlikely(error)) | |
1119 | break; | |
1120 | ||
1121 | /* | |
1122 | * Sanity check this iovec. 0 read succeeds. | |
1123 | */ | |
1124 | if (unlikely(!len)) | |
1125 | break; | |
1126 | error = -EFAULT; | |
1127 | if (unlikely(!base)) | |
1128 | break; | |
1129 | ||
1130 | /* | |
1131 | * Get this base offset and number of pages, then map | |
1132 | * in the user pages. | |
1133 | */ | |
1134 | off = (unsigned long) base & ~PAGE_MASK; | |
7afa6fd0 JA |
1135 | |
1136 | /* | |
1137 | * If asked for alignment, the offset must be zero and the | |
1138 | * length a multiple of the PAGE_SIZE. | |
1139 | */ | |
1140 | error = -EINVAL; | |
1141 | if (aligned && (off || len & ~PAGE_MASK)) | |
1142 | break; | |
1143 | ||
912d35f8 JA |
1144 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1145 | if (npages > PIPE_BUFFERS - buffers) | |
1146 | npages = PIPE_BUFFERS - buffers; | |
1147 | ||
1148 | error = get_user_pages(current, current->mm, | |
1149 | (unsigned long) base, npages, 0, 0, | |
1150 | &pages[buffers], NULL); | |
1151 | ||
1152 | if (unlikely(error <= 0)) | |
1153 | break; | |
1154 | ||
1155 | /* | |
1156 | * Fill this contiguous range into the partial page map. | |
1157 | */ | |
1158 | for (i = 0; i < error; i++) { | |
7591489a | 1159 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
912d35f8 JA |
1160 | |
1161 | partial[buffers].offset = off; | |
1162 | partial[buffers].len = plen; | |
1163 | ||
1164 | off = 0; | |
1165 | len -= plen; | |
1166 | buffers++; | |
1167 | } | |
1168 | ||
1169 | /* | |
1170 | * We didn't complete this iov, stop here since it probably | |
1171 | * means we have to move some of this into a pipe to | |
1172 | * be able to continue. | |
1173 | */ | |
1174 | if (len) | |
1175 | break; | |
1176 | ||
1177 | /* | |
1178 | * Don't continue if we mapped fewer pages than we asked for, | |
1179 | * or if we mapped the max number of pages that we have | |
1180 | * room for. | |
1181 | */ | |
1182 | if (error < npages || buffers == PIPE_BUFFERS) | |
1183 | break; | |
1184 | ||
1185 | nr_vecs--; | |
1186 | iov++; | |
1187 | } | |
1188 | ||
1189 | up_read(¤t->mm->mmap_sem); | |
1190 | ||
1191 | if (buffers) | |
1192 | return buffers; | |
1193 | ||
1194 | return error; | |
1195 | } | |
1196 | ||
1197 | /* | |
1198 | * vmsplice splices a user address range into a pipe. It can be thought of | |
1199 | * as splice-from-memory, where the regular splice is splice-from-file (or | |
1200 | * to file). In both cases the output is a pipe, naturally. | |
1201 | * | |
1202 | * Note that vmsplice only supports splicing _from_ user memory to a pipe, | |
1203 | * not the other way around. Splicing from user memory is a simple operation | |
1204 | * that can be supported without any funky alignment restrictions or nasty | |
1205 | * vm tricks. We simply map in the user memory and fill them into a pipe. | |
1206 | * The reverse isn't quite as easy, though. There are two possible solutions | |
1207 | * for that: | |
1208 | * | |
1209 | * - memcpy() the data internally, at which point we might as well just | |
1210 | * do a regular read() on the buffer anyway. | |
1211 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it | |
1212 | * has restriction limitations on both ends of the pipe). | |
1213 | * | |
1214 | * Alas, it isn't here. | |
1215 | * | |
1216 | */ | |
1217 | static long do_vmsplice(struct file *file, const struct iovec __user *iov, | |
1218 | unsigned long nr_segs, unsigned int flags) | |
1219 | { | |
1220 | struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; | |
1221 | struct page *pages[PIPE_BUFFERS]; | |
1222 | struct partial_page partial[PIPE_BUFFERS]; | |
1223 | struct splice_pipe_desc spd = { | |
1224 | .pages = pages, | |
1225 | .partial = partial, | |
1226 | .flags = flags, | |
1227 | .ops = &user_page_pipe_buf_ops, | |
1228 | }; | |
1229 | ||
1230 | if (unlikely(!pipe)) | |
1231 | return -EBADF; | |
1232 | if (unlikely(nr_segs > UIO_MAXIOV)) | |
1233 | return -EINVAL; | |
1234 | else if (unlikely(!nr_segs)) | |
1235 | return 0; | |
1236 | ||
7afa6fd0 JA |
1237 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
1238 | flags & SPLICE_F_GIFT); | |
912d35f8 JA |
1239 | if (spd.nr_pages <= 0) |
1240 | return spd.nr_pages; | |
1241 | ||
00522fb4 | 1242 | return splice_to_pipe(pipe, &spd); |
912d35f8 JA |
1243 | } |
1244 | ||
1245 | asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, | |
1246 | unsigned long nr_segs, unsigned int flags) | |
1247 | { | |
1248 | struct file *file; | |
1249 | long error; | |
1250 | int fput; | |
1251 | ||
1252 | error = -EBADF; | |
1253 | file = fget_light(fd, &fput); | |
1254 | if (file) { | |
1255 | if (file->f_mode & FMODE_WRITE) | |
1256 | error = do_vmsplice(file, iov, nr_segs, flags); | |
1257 | ||
1258 | fput_light(file, fput); | |
1259 | } | |
1260 | ||
1261 | return error; | |
1262 | } | |
1263 | ||
529565dc IM |
1264 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
1265 | int fd_out, loff_t __user *off_out, | |
1266 | size_t len, unsigned int flags) | |
5274f052 JA |
1267 | { |
1268 | long error; | |
1269 | struct file *in, *out; | |
1270 | int fput_in, fput_out; | |
1271 | ||
1272 | if (unlikely(!len)) | |
1273 | return 0; | |
1274 | ||
1275 | error = -EBADF; | |
529565dc | 1276 | in = fget_light(fd_in, &fput_in); |
5274f052 JA |
1277 | if (in) { |
1278 | if (in->f_mode & FMODE_READ) { | |
529565dc | 1279 | out = fget_light(fd_out, &fput_out); |
5274f052 JA |
1280 | if (out) { |
1281 | if (out->f_mode & FMODE_WRITE) | |
529565dc IM |
1282 | error = do_splice(in, off_in, |
1283 | out, off_out, | |
1284 | len, flags); | |
5274f052 JA |
1285 | fput_light(out, fput_out); |
1286 | } | |
1287 | } | |
1288 | ||
1289 | fput_light(in, fput_in); | |
1290 | } | |
1291 | ||
1292 | return error; | |
1293 | } | |
70524490 JA |
1294 | |
1295 | /* | |
1296 | * Link contents of ipipe to opipe. | |
1297 | */ | |
1298 | static int link_pipe(struct pipe_inode_info *ipipe, | |
1299 | struct pipe_inode_info *opipe, | |
1300 | size_t len, unsigned int flags) | |
1301 | { | |
1302 | struct pipe_buffer *ibuf, *obuf; | |
2a27250e JA |
1303 | int ret, do_wakeup, i, ipipe_first; |
1304 | ||
1305 | ret = do_wakeup = ipipe_first = 0; | |
70524490 JA |
1306 | |
1307 | /* | |
1308 | * Potential ABBA deadlock, work around it by ordering lock | |
1309 | * grabbing by inode address. Otherwise two different processes | |
1310 | * could deadlock (one doing tee from A -> B, the other from B -> A). | |
1311 | */ | |
1312 | if (ipipe->inode < opipe->inode) { | |
2a27250e | 1313 | ipipe_first = 1; |
70524490 JA |
1314 | mutex_lock(&ipipe->inode->i_mutex); |
1315 | mutex_lock(&opipe->inode->i_mutex); | |
1316 | } else { | |
1317 | mutex_lock(&opipe->inode->i_mutex); | |
1318 | mutex_lock(&ipipe->inode->i_mutex); | |
1319 | } | |
1320 | ||
1321 | for (i = 0;; i++) { | |
1322 | if (!opipe->readers) { | |
1323 | send_sig(SIGPIPE, current, 0); | |
1324 | if (!ret) | |
1325 | ret = -EPIPE; | |
1326 | break; | |
1327 | } | |
1328 | if (ipipe->nrbufs - i) { | |
1329 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); | |
1330 | ||
1331 | /* | |
1332 | * If we have room, fill this buffer | |
1333 | */ | |
1334 | if (opipe->nrbufs < PIPE_BUFFERS) { | |
1335 | int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); | |
1336 | ||
1337 | /* | |
1338 | * Get a reference to this pipe buffer, | |
1339 | * so we can copy the contents over. | |
1340 | */ | |
1341 | ibuf->ops->get(ipipe, ibuf); | |
1342 | ||
1343 | obuf = opipe->bufs + nbuf; | |
1344 | *obuf = *ibuf; | |
1345 | ||
7afa6fd0 JA |
1346 | /* |
1347 | * Don't inherit the gift flag, we need to | |
1348 | * prevent multiple steals of this page. | |
1349 | */ | |
1350 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; | |
1351 | ||
70524490 JA |
1352 | if (obuf->len > len) |
1353 | obuf->len = len; | |
1354 | ||
1355 | opipe->nrbufs++; | |
1356 | do_wakeup = 1; | |
1357 | ret += obuf->len; | |
1358 | len -= obuf->len; | |
1359 | ||
1360 | if (!len) | |
1361 | break; | |
1362 | if (opipe->nrbufs < PIPE_BUFFERS) | |
1363 | continue; | |
1364 | } | |
1365 | ||
1366 | /* | |
1367 | * We have input available, but no output room. | |
2a27250e JA |
1368 | * If we already copied data, return that. If we |
1369 | * need to drop the opipe lock, it must be ordered | |
1370 | * last to avoid deadlocks. | |
70524490 | 1371 | */ |
2a27250e | 1372 | if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { |
70524490 JA |
1373 | if (!ret) |
1374 | ret = -EAGAIN; | |
1375 | break; | |
1376 | } | |
1377 | if (signal_pending(current)) { | |
1378 | if (!ret) | |
1379 | ret = -ERESTARTSYS; | |
1380 | break; | |
1381 | } | |
1382 | if (do_wakeup) { | |
1383 | smp_mb(); | |
1384 | if (waitqueue_active(&opipe->wait)) | |
1385 | wake_up_interruptible(&opipe->wait); | |
1386 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); | |
1387 | do_wakeup = 0; | |
1388 | } | |
1389 | ||
1390 | opipe->waiting_writers++; | |
1391 | pipe_wait(opipe); | |
1392 | opipe->waiting_writers--; | |
1393 | continue; | |
1394 | } | |
1395 | ||
1396 | /* | |
1397 | * No input buffers, do the usual checks for available | |
1398 | * writers and blocking and wait if necessary | |
1399 | */ | |
1400 | if (!ipipe->writers) | |
1401 | break; | |
1402 | if (!ipipe->waiting_writers) { | |
1403 | if (ret) | |
1404 | break; | |
1405 | } | |
2a27250e JA |
1406 | /* |
1407 | * pipe_wait() drops the ipipe mutex. To avoid deadlocks | |
1408 | * with another process, we can only safely do that if | |
1409 | * the ipipe lock is ordered last. | |
1410 | */ | |
1411 | if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { | |
70524490 JA |
1412 | if (!ret) |
1413 | ret = -EAGAIN; | |
1414 | break; | |
1415 | } | |
1416 | if (signal_pending(current)) { | |
1417 | if (!ret) | |
1418 | ret = -ERESTARTSYS; | |
1419 | break; | |
1420 | } | |
1421 | ||
1422 | if (waitqueue_active(&ipipe->wait)) | |
1423 | wake_up_interruptible_sync(&ipipe->wait); | |
1424 | kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); | |
1425 | ||
1426 | pipe_wait(ipipe); | |
1427 | } | |
1428 | ||
1429 | mutex_unlock(&ipipe->inode->i_mutex); | |
1430 | mutex_unlock(&opipe->inode->i_mutex); | |
1431 | ||
1432 | if (do_wakeup) { | |
1433 | smp_mb(); | |
1434 | if (waitqueue_active(&opipe->wait)) | |
1435 | wake_up_interruptible(&opipe->wait); | |
1436 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); | |
1437 | } | |
1438 | ||
1439 | return ret; | |
1440 | } | |
1441 | ||
1442 | /* | |
1443 | * This is a tee(1) implementation that works on pipes. It doesn't copy | |
1444 | * any data, it simply references the 'in' pages on the 'out' pipe. | |
1445 | * The 'flags' used are the SPLICE_F_* variants, currently the only | |
1446 | * applicable one is SPLICE_F_NONBLOCK. | |
1447 | */ | |
1448 | static long do_tee(struct file *in, struct file *out, size_t len, | |
1449 | unsigned int flags) | |
1450 | { | |
1451 | struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; | |
1452 | struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; | |
1453 | ||
1454 | /* | |
1455 | * Link ipipe to the two output pipes, consuming as we go along. | |
1456 | */ | |
1457 | if (ipipe && opipe) | |
1458 | return link_pipe(ipipe, opipe, len, flags); | |
1459 | ||
1460 | return -EINVAL; | |
1461 | } | |
1462 | ||
1463 | asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) | |
1464 | { | |
1465 | struct file *in; | |
1466 | int error, fput_in; | |
1467 | ||
1468 | if (unlikely(!len)) | |
1469 | return 0; | |
1470 | ||
1471 | error = -EBADF; | |
1472 | in = fget_light(fdin, &fput_in); | |
1473 | if (in) { | |
1474 | if (in->f_mode & FMODE_READ) { | |
1475 | int fput_out; | |
1476 | struct file *out = fget_light(fdout, &fput_out); | |
1477 | ||
1478 | if (out) { | |
1479 | if (out->f_mode & FMODE_WRITE) | |
1480 | error = do_tee(in, out, len, flags); | |
1481 | fput_light(out, fput_out); | |
1482 | } | |
1483 | } | |
1484 | fput_light(in, fput_in); | |
1485 | } | |
1486 | ||
1487 | return error; | |
1488 | } |