Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
5274f052 JA |
2 | /* |
3 | * "splice": joining two ropes together by interweaving their strands. | |
4 | * | |
5 | * This is the "extended pipe" functionality, where a pipe is used as | |
6 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel | |
7 | * buffer that you can use to transfer data from one end to the other. | |
8 | * | |
9 | * The traditional unix read/write is extended with a "splice()" operation | |
10 | * that transfers data buffers to or from a pipe buffer. | |
11 | * | |
12 | * Named by Larry McVoy, original implementation from Linus, extended by | |
c2058e06 JA |
13 | * Jens to support splicing to files, network, direct splicing, etc and |
14 | * fixing lots of bugs. | |
5274f052 | 15 | * |
0fe23479 | 16 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
c2058e06 JA |
17 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
18 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> | |
5274f052 JA |
19 | * |
20 | */ | |
be297968 | 21 | #include <linux/bvec.h> |
5274f052 JA |
22 | #include <linux/fs.h> |
23 | #include <linux/file.h> | |
24 | #include <linux/pagemap.h> | |
d6b29d7c | 25 | #include <linux/splice.h> |
08e552c6 | 26 | #include <linux/memcontrol.h> |
5274f052 | 27 | #include <linux/mm_inline.h> |
5abc97aa | 28 | #include <linux/swap.h> |
4f6f0bd2 | 29 | #include <linux/writeback.h> |
630d9c47 | 30 | #include <linux/export.h> |
4f6f0bd2 | 31 | #include <linux/syscalls.h> |
912d35f8 | 32 | #include <linux/uio.h> |
983652c6 | 33 | #include <linux/fsnotify.h> |
29ce2058 | 34 | #include <linux/security.h> |
5a0e3ad6 | 35 | #include <linux/gfp.h> |
2dc334f1 | 36 | #include <linux/net.h> |
35f9c09f | 37 | #include <linux/socket.h> |
174cd4b1 IM |
38 | #include <linux/sched/signal.h> |
39 | ||
06ae43f3 | 40 | #include "internal.h" |
5274f052 | 41 | |
0f99fc51 JA |
42 | /* |
43 | * Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to | |
44 | * indicate they support non-blocking reads or writes, we must clear it | |
45 | * here if set to avoid blocking other users of this pipe if splice is | |
46 | * being done on it. | |
47 | */ | |
48 | static noinline void noinline pipe_clear_nowait(struct file *file) | |
49 | { | |
50 | fmode_t fmode = READ_ONCE(file->f_mode); | |
51 | ||
52 | do { | |
53 | if (!(fmode & FMODE_NOWAIT)) | |
54 | break; | |
55 | } while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT)); | |
56 | } | |
57 | ||
83f9135b JA |
58 | /* |
59 | * Attempt to steal a page from a pipe buffer. This should perhaps go into | |
60 | * a vm helper function, it's already simplified quite a bit by the | |
61 | * addition of remove_mapping(). If success is returned, the caller may | |
62 | * attempt to reuse this page for another destination. | |
63 | */ | |
c928f642 CH |
64 | static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
65 | struct pipe_buffer *buf) | |
5abc97aa | 66 | { |
5100da38 | 67 | struct folio *folio = page_folio(buf->page); |
9e94cd4f | 68 | struct address_space *mapping; |
5abc97aa | 69 | |
b9ccad2e | 70 | folio_lock(folio); |
9e0267c2 | 71 | |
b9ccad2e | 72 | mapping = folio_mapping(folio); |
9e94cd4f | 73 | if (mapping) { |
b9ccad2e | 74 | WARN_ON(!folio_test_uptodate(folio)); |
5abc97aa | 75 | |
9e94cd4f JA |
76 | /* |
77 | * At least for ext2 with nobh option, we need to wait on | |
b9ccad2e | 78 | * writeback completing on this folio, since we'll remove it |
9e94cd4f | 79 | * from the pagecache. Otherwise truncate wont wait on the |
b9ccad2e | 80 | * folio, allowing the disk blocks to be reused by someone else |
9e94cd4f JA |
81 | * before we actually wrote our data to them. fs corruption |
82 | * ensues. | |
83 | */ | |
b9ccad2e | 84 | folio_wait_writeback(folio); |
ad8d6f0a | 85 | |
b9ccad2e MWO |
86 | if (folio_has_private(folio) && |
87 | !filemap_release_folio(folio, GFP_KERNEL)) | |
ca39d651 | 88 | goto out_unlock; |
4f6f0bd2 | 89 | |
9e94cd4f JA |
90 | /* |
91 | * If we succeeded in removing the mapping, set LRU flag | |
92 | * and return good. | |
93 | */ | |
5100da38 | 94 | if (remove_mapping(mapping, folio)) { |
9e94cd4f | 95 | buf->flags |= PIPE_BUF_FLAG_LRU; |
c928f642 | 96 | return true; |
9e94cd4f | 97 | } |
9e0267c2 | 98 | } |
5abc97aa | 99 | |
9e94cd4f | 100 | /* |
b9ccad2e | 101 | * Raced with truncate or failed to remove folio from current |
9e94cd4f JA |
102 | * address space, unlock and return failure. |
103 | */ | |
ca39d651 | 104 | out_unlock: |
b9ccad2e | 105 | folio_unlock(folio); |
c928f642 | 106 | return false; |
5abc97aa JA |
107 | } |
108 | ||
76ad4d11 | 109 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
5274f052 JA |
110 | struct pipe_buffer *buf) |
111 | { | |
09cbfeaf | 112 | put_page(buf->page); |
1432873a | 113 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
5274f052 JA |
114 | } |
115 | ||
0845718d JA |
116 | /* |
117 | * Check whether the contents of buf is OK to access. Since the content | |
118 | * is a page cache page, IO may be in flight. | |
119 | */ | |
cac36bb0 JA |
120 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
121 | struct pipe_buffer *buf) | |
5274f052 JA |
122 | { |
123 | struct page *page = buf->page; | |
49d0b21b | 124 | int err; |
5274f052 JA |
125 | |
126 | if (!PageUptodate(page)) { | |
49d0b21b JA |
127 | lock_page(page); |
128 | ||
129 | /* | |
130 | * Page got truncated/unhashed. This will cause a 0-byte | |
73d62d83 | 131 | * splice, if this is the first page. |
49d0b21b JA |
132 | */ |
133 | if (!page->mapping) { | |
134 | err = -ENODATA; | |
135 | goto error; | |
136 | } | |
5274f052 | 137 | |
49d0b21b | 138 | /* |
73d62d83 | 139 | * Uh oh, read-error from disk. |
49d0b21b JA |
140 | */ |
141 | if (!PageUptodate(page)) { | |
142 | err = -EIO; | |
143 | goto error; | |
144 | } | |
145 | ||
146 | /* | |
f84d7519 | 147 | * Page is ok afterall, we are done. |
49d0b21b | 148 | */ |
5274f052 | 149 | unlock_page(page); |
5274f052 JA |
150 | } |
151 | ||
f84d7519 | 152 | return 0; |
49d0b21b JA |
153 | error: |
154 | unlock_page(page); | |
f84d7519 | 155 | return err; |
70524490 JA |
156 | } |
157 | ||
708e3508 | 158 | const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
c928f642 CH |
159 | .confirm = page_cache_pipe_buf_confirm, |
160 | .release = page_cache_pipe_buf_release, | |
161 | .try_steal = page_cache_pipe_buf_try_steal, | |
162 | .get = generic_pipe_buf_get, | |
5274f052 JA |
163 | }; |
164 | ||
c928f642 CH |
165 | static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
166 | struct pipe_buffer *buf) | |
912d35f8 | 167 | { |
7afa6fd0 | 168 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
c928f642 | 169 | return false; |
7afa6fd0 | 170 | |
1432873a | 171 | buf->flags |= PIPE_BUF_FLAG_LRU; |
c928f642 | 172 | return generic_pipe_buf_try_steal(pipe, buf); |
912d35f8 JA |
173 | } |
174 | ||
d4c3cca9 | 175 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
c928f642 CH |
176 | .release = page_cache_pipe_buf_release, |
177 | .try_steal = user_page_pipe_buf_try_steal, | |
178 | .get = generic_pipe_buf_get, | |
912d35f8 JA |
179 | }; |
180 | ||
825cdcb1 NK |
181 | static void wakeup_pipe_readers(struct pipe_inode_info *pipe) |
182 | { | |
183 | smp_mb(); | |
0ddad21d LT |
184 | if (waitqueue_active(&pipe->rd_wait)) |
185 | wake_up_interruptible(&pipe->rd_wait); | |
825cdcb1 NK |
186 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
187 | } | |
188 | ||
932cc6d4 JA |
189 | /** |
190 | * splice_to_pipe - fill passed data into a pipe | |
191 | * @pipe: pipe to fill | |
192 | * @spd: data to fill | |
193 | * | |
194 | * Description: | |
79685b8d | 195 | * @spd contains a map of pages and len/offset tuples, along with |
932cc6d4 JA |
196 | * the struct pipe_buf_operations associated with these pages. This |
197 | * function will link that data to the pipe. | |
198 | * | |
83f9135b | 199 | */ |
d6b29d7c JA |
200 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
201 | struct splice_pipe_desc *spd) | |
5274f052 | 202 | { |
00de00bd | 203 | unsigned int spd_pages = spd->nr_pages; |
8cefc107 DH |
204 | unsigned int tail = pipe->tail; |
205 | unsigned int head = pipe->head; | |
206 | unsigned int mask = pipe->ring_size - 1; | |
8924feff | 207 | int ret = 0, page_nr = 0; |
5274f052 | 208 | |
d6785d91 RV |
209 | if (!spd_pages) |
210 | return 0; | |
211 | ||
8924feff AV |
212 | if (unlikely(!pipe->readers)) { |
213 | send_sig(SIGPIPE, current, 0); | |
214 | ret = -EPIPE; | |
215 | goto out; | |
216 | } | |
5274f052 | 217 | |
6718b6f8 | 218 | while (!pipe_full(head, tail, pipe->max_usage)) { |
8cefc107 | 219 | struct pipe_buffer *buf = &pipe->bufs[head & mask]; |
5274f052 | 220 | |
8924feff AV |
221 | buf->page = spd->pages[page_nr]; |
222 | buf->offset = spd->partial[page_nr].offset; | |
223 | buf->len = spd->partial[page_nr].len; | |
224 | buf->private = spd->partial[page_nr].private; | |
225 | buf->ops = spd->ops; | |
5a81e6a1 | 226 | buf->flags = 0; |
5274f052 | 227 | |
8cefc107 DH |
228 | head++; |
229 | pipe->head = head; | |
8924feff AV |
230 | page_nr++; |
231 | ret += buf->len; | |
29e35094 | 232 | |
8924feff | 233 | if (!--spd->nr_pages) |
5274f052 | 234 | break; |
5274f052 JA |
235 | } |
236 | ||
8924feff AV |
237 | if (!ret) |
238 | ret = -EAGAIN; | |
5274f052 | 239 | |
8924feff | 240 | out: |
00de00bd | 241 | while (page_nr < spd_pages) |
bbdfc2f7 | 242 | spd->spd_release(spd, page_nr++); |
5274f052 JA |
243 | |
244 | return ret; | |
245 | } | |
2b514574 | 246 | EXPORT_SYMBOL_GPL(splice_to_pipe); |
5274f052 | 247 | |
79fddc4e AV |
248 | ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
249 | { | |
8cefc107 DH |
250 | unsigned int head = pipe->head; |
251 | unsigned int tail = pipe->tail; | |
252 | unsigned int mask = pipe->ring_size - 1; | |
79fddc4e AV |
253 | int ret; |
254 | ||
255 | if (unlikely(!pipe->readers)) { | |
256 | send_sig(SIGPIPE, current, 0); | |
257 | ret = -EPIPE; | |
6718b6f8 | 258 | } else if (pipe_full(head, tail, pipe->max_usage)) { |
79fddc4e AV |
259 | ret = -EAGAIN; |
260 | } else { | |
8cefc107 DH |
261 | pipe->bufs[head & mask] = *buf; |
262 | pipe->head = head + 1; | |
79fddc4e AV |
263 | return buf->len; |
264 | } | |
a779638c | 265 | pipe_buf_release(pipe, buf); |
79fddc4e AV |
266 | return ret; |
267 | } | |
268 | EXPORT_SYMBOL(add_to_pipe); | |
269 | ||
35f3d14d JA |
270 | /* |
271 | * Check if we need to grow the arrays holding pages and partial page | |
272 | * descriptions. | |
273 | */ | |
047fe360 | 274 | int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) |
35f3d14d | 275 | { |
6718b6f8 | 276 | unsigned int max_usage = READ_ONCE(pipe->max_usage); |
047fe360 | 277 | |
8cefc107 DH |
278 | spd->nr_pages_max = max_usage; |
279 | if (max_usage <= PIPE_DEF_BUFFERS) | |
35f3d14d JA |
280 | return 0; |
281 | ||
8cefc107 DH |
282 | spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); |
283 | spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), | |
6da2ec56 | 284 | GFP_KERNEL); |
35f3d14d JA |
285 | |
286 | if (spd->pages && spd->partial) | |
287 | return 0; | |
288 | ||
289 | kfree(spd->pages); | |
290 | kfree(spd->partial); | |
291 | return -ENOMEM; | |
292 | } | |
293 | ||
047fe360 | 294 | void splice_shrink_spd(struct splice_pipe_desc *spd) |
35f3d14d | 295 | { |
047fe360 | 296 | if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) |
35f3d14d JA |
297 | return; |
298 | ||
299 | kfree(spd->pages); | |
300 | kfree(spd->partial); | |
301 | } | |
302 | ||
33b3b041 DH |
303 | /* |
304 | * Splice data from an O_DIRECT file into pages and then add them to the output | |
305 | * pipe. | |
306 | */ | |
307 | ssize_t direct_splice_read(struct file *in, loff_t *ppos, | |
308 | struct pipe_inode_info *pipe, | |
309 | size_t len, unsigned int flags) | |
310 | { | |
311 | struct iov_iter to; | |
312 | struct bio_vec *bv; | |
313 | struct kiocb kiocb; | |
314 | struct page **pages; | |
315 | ssize_t ret; | |
316 | size_t used, npages, chunk, remain, reclaim; | |
317 | int i; | |
318 | ||
319 | /* Work out how much data we can actually add into the pipe */ | |
320 | used = pipe_occupancy(pipe->head, pipe->tail); | |
321 | npages = max_t(ssize_t, pipe->max_usage - used, 0); | |
322 | len = min_t(size_t, len, npages * PAGE_SIZE); | |
323 | npages = DIV_ROUND_UP(len, PAGE_SIZE); | |
324 | ||
325 | bv = kzalloc(array_size(npages, sizeof(bv[0])) + | |
326 | array_size(npages, sizeof(struct page *)), GFP_KERNEL); | |
327 | if (!bv) | |
328 | return -ENOMEM; | |
329 | ||
330 | pages = (void *)(bv + npages); | |
331 | npages = alloc_pages_bulk_array(GFP_USER, npages, pages); | |
332 | if (!npages) { | |
333 | kfree(bv); | |
334 | return -ENOMEM; | |
335 | } | |
336 | ||
337 | remain = len = min_t(size_t, len, npages * PAGE_SIZE); | |
338 | ||
339 | for (i = 0; i < npages; i++) { | |
340 | chunk = min_t(size_t, PAGE_SIZE, remain); | |
341 | bv[i].bv_page = pages[i]; | |
342 | bv[i].bv_offset = 0; | |
343 | bv[i].bv_len = chunk; | |
344 | remain -= chunk; | |
345 | } | |
346 | ||
347 | /* Do the I/O */ | |
348 | iov_iter_bvec(&to, ITER_DEST, bv, npages, len); | |
349 | init_sync_kiocb(&kiocb, in); | |
350 | kiocb.ki_pos = *ppos; | |
351 | ret = call_read_iter(in, &kiocb, &to); | |
352 | ||
353 | reclaim = npages * PAGE_SIZE; | |
354 | remain = 0; | |
355 | if (ret > 0) { | |
356 | reclaim -= ret; | |
357 | remain = ret; | |
358 | *ppos = kiocb.ki_pos; | |
359 | file_accessed(in); | |
360 | } else if (ret < 0) { | |
361 | /* | |
362 | * callers of ->splice_read() expect -EAGAIN on | |
363 | * "can't put anything in there", rather than -EFAULT. | |
364 | */ | |
365 | if (ret == -EFAULT) | |
366 | ret = -EAGAIN; | |
367 | } | |
368 | ||
369 | /* Free any pages that didn't get touched at all. */ | |
370 | reclaim /= PAGE_SIZE; | |
371 | if (reclaim) { | |
372 | npages -= reclaim; | |
373 | release_pages(pages + npages, reclaim); | |
374 | } | |
375 | ||
376 | /* Push the remaining pages into the pipe. */ | |
377 | for (i = 0; i < npages; i++) { | |
378 | struct pipe_buffer *buf = pipe_head_buf(pipe); | |
379 | ||
380 | chunk = min_t(size_t, remain, PAGE_SIZE); | |
381 | *buf = (struct pipe_buffer) { | |
382 | .ops = &default_pipe_buf_ops, | |
383 | .page = bv[i].bv_page, | |
384 | .offset = 0, | |
385 | .len = chunk, | |
386 | }; | |
387 | pipe->head++; | |
388 | remain -= chunk; | |
389 | } | |
390 | ||
391 | kfree(bv); | |
392 | return ret; | |
393 | } | |
7c8e01eb | 394 | EXPORT_SYMBOL(direct_splice_read); |
33b3b041 | 395 | |
83f9135b JA |
396 | /** |
397 | * generic_file_splice_read - splice data from file to a pipe | |
398 | * @in: file to splice from | |
932cc6d4 | 399 | * @ppos: position in @in |
83f9135b JA |
400 | * @pipe: pipe to splice to |
401 | * @len: number of bytes to splice | |
402 | * @flags: splice modifier flags | |
403 | * | |
932cc6d4 JA |
404 | * Description: |
405 | * Will read pages from given file and fill them into a pipe. Can be | |
82c156f8 | 406 | * used as long as it has more or less sane ->read_iter(). |
932cc6d4 | 407 | * |
83f9135b | 408 | */ |
cbb7e577 JA |
409 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
410 | struct pipe_inode_info *pipe, size_t len, | |
411 | unsigned int flags) | |
5274f052 | 412 | { |
82c156f8 AV |
413 | struct iov_iter to; |
414 | struct kiocb kiocb; | |
8cefc107 | 415 | int ret; |
be64f884 | 416 | |
de4eda9d | 417 | iov_iter_pipe(&to, ITER_DEST, pipe, len); |
82c156f8 AV |
418 | init_sync_kiocb(&kiocb, in); |
419 | kiocb.ki_pos = *ppos; | |
bb7462b6 | 420 | ret = call_read_iter(in, &kiocb, &to); |
723590ed | 421 | if (ret > 0) { |
82c156f8 | 422 | *ppos = kiocb.ki_pos; |
723590ed | 423 | file_accessed(in); |
82c156f8 | 424 | } else if (ret < 0) { |
0d964934 AV |
425 | /* free what was emitted */ |
426 | pipe_discard_from(pipe, to.start_head); | |
82c156f8 AV |
427 | /* |
428 | * callers of ->splice_read() expect -EAGAIN on | |
429 | * "can't put anything in there", rather than -EFAULT. | |
430 | */ | |
431 | if (ret == -EFAULT) | |
432 | ret = -EAGAIN; | |
723590ed | 433 | } |
5274f052 JA |
434 | |
435 | return ret; | |
436 | } | |
059a8f37 JA |
437 | EXPORT_SYMBOL(generic_file_splice_read); |
438 | ||
241699cd | 439 | const struct pipe_buf_operations default_pipe_buf_ops = { |
c928f642 CH |
440 | .release = generic_pipe_buf_release, |
441 | .try_steal = generic_pipe_buf_try_steal, | |
442 | .get = generic_pipe_buf_get, | |
6818173b MS |
443 | }; |
444 | ||
28a625cb MS |
445 | /* Pipe buffer operations for a socket and similar. */ |
446 | const struct pipe_buf_operations nosteal_pipe_buf_ops = { | |
c928f642 CH |
447 | .release = generic_pipe_buf_release, |
448 | .get = generic_pipe_buf_get, | |
28a625cb MS |
449 | }; |
450 | EXPORT_SYMBOL(nosteal_pipe_buf_ops); | |
451 | ||
b3c2d2dd MS |
452 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
453 | { | |
454 | smp_mb(); | |
0ddad21d LT |
455 | if (waitqueue_active(&pipe->wr_wait)) |
456 | wake_up_interruptible(&pipe->wr_wait); | |
b3c2d2dd MS |
457 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
458 | } | |
459 | ||
932cc6d4 | 460 | /** |
b3c2d2dd | 461 | * splice_from_pipe_feed - feed available data from a pipe to a file |
932cc6d4 JA |
462 | * @pipe: pipe to splice from |
463 | * @sd: information to @actor | |
464 | * @actor: handler that splices the data | |
465 | * | |
466 | * Description: | |
b3c2d2dd MS |
467 | * This function loops over the pipe and calls @actor to do the |
468 | * actual moving of a single struct pipe_buffer to the desired | |
469 | * destination. It returns when there's no more buffers left in | |
470 | * the pipe or if the requested number of bytes (@sd->total_len) | |
471 | * have been copied. It returns a positive number (one) if the | |
472 | * pipe needs to be filled with more data, zero if the required | |
473 | * number of bytes have been copied and -errno on error. | |
932cc6d4 | 474 | * |
b3c2d2dd MS |
475 | * This, together with splice_from_pipe_{begin,end,next}, may be |
476 | * used to implement the functionality of __splice_from_pipe() when | |
477 | * locking is required around copying the pipe buffers to the | |
478 | * destination. | |
83f9135b | 479 | */ |
96f9bc8f | 480 | static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
b3c2d2dd | 481 | splice_actor *actor) |
5274f052 | 482 | { |
8cefc107 DH |
483 | unsigned int head = pipe->head; |
484 | unsigned int tail = pipe->tail; | |
485 | unsigned int mask = pipe->ring_size - 1; | |
b3c2d2dd | 486 | int ret; |
5274f052 | 487 | |
ec057595 | 488 | while (!pipe_empty(head, tail)) { |
8cefc107 | 489 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
5274f052 | 490 | |
b3c2d2dd MS |
491 | sd->len = buf->len; |
492 | if (sd->len > sd->total_len) | |
493 | sd->len = sd->total_len; | |
5274f052 | 494 | |
fba597db | 495 | ret = pipe_buf_confirm(pipe, buf); |
a8adbe37 | 496 | if (unlikely(ret)) { |
b3c2d2dd MS |
497 | if (ret == -ENODATA) |
498 | ret = 0; | |
499 | return ret; | |
500 | } | |
a8adbe37 MM |
501 | |
502 | ret = actor(pipe, buf, sd); | |
503 | if (ret <= 0) | |
504 | return ret; | |
505 | ||
b3c2d2dd MS |
506 | buf->offset += ret; |
507 | buf->len -= ret; | |
508 | ||
509 | sd->num_spliced += ret; | |
510 | sd->len -= ret; | |
511 | sd->pos += ret; | |
512 | sd->total_len -= ret; | |
513 | ||
514 | if (!buf->len) { | |
a779638c | 515 | pipe_buf_release(pipe, buf); |
8cefc107 DH |
516 | tail++; |
517 | pipe->tail = tail; | |
6447a3cf | 518 | if (pipe->files) |
b3c2d2dd MS |
519 | sd->need_wakeup = true; |
520 | } | |
5274f052 | 521 | |
b3c2d2dd MS |
522 | if (!sd->total_len) |
523 | return 0; | |
524 | } | |
5274f052 | 525 | |
b3c2d2dd MS |
526 | return 1; |
527 | } | |
5274f052 | 528 | |
d1a819a2 LT |
529 | /* We know we have a pipe buffer, but maybe it's empty? */ |
530 | static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) | |
531 | { | |
532 | unsigned int tail = pipe->tail; | |
533 | unsigned int mask = pipe->ring_size - 1; | |
534 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
535 | ||
536 | if (unlikely(!buf->len)) { | |
537 | pipe_buf_release(pipe, buf); | |
538 | pipe->tail = tail+1; | |
539 | return true; | |
540 | } | |
541 | ||
542 | return false; | |
543 | } | |
544 | ||
b3c2d2dd MS |
545 | /** |
546 | * splice_from_pipe_next - wait for some data to splice from | |
547 | * @pipe: pipe to splice from | |
548 | * @sd: information about the splice operation | |
549 | * | |
550 | * Description: | |
551 | * This function will wait for some data and return a positive | |
552 | * value (one) if pipe buffers are available. It will return zero | |
553 | * or -errno if no more data needs to be spliced. | |
554 | */ | |
96f9bc8f | 555 | static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
b3c2d2dd | 556 | { |
c725bfce JK |
557 | /* |
558 | * Check for signal early to make process killable when there are | |
559 | * always buffers available | |
560 | */ | |
561 | if (signal_pending(current)) | |
562 | return -ERESTARTSYS; | |
563 | ||
d1a819a2 | 564 | repeat: |
8cefc107 | 565 | while (pipe_empty(pipe->head, pipe->tail)) { |
b3c2d2dd MS |
566 | if (!pipe->writers) |
567 | return 0; | |
016b661e | 568 | |
a28c8b9d | 569 | if (sd->num_spliced) |
b3c2d2dd | 570 | return 0; |
73d62d83 | 571 | |
b3c2d2dd MS |
572 | if (sd->flags & SPLICE_F_NONBLOCK) |
573 | return -EAGAIN; | |
5274f052 | 574 | |
b3c2d2dd MS |
575 | if (signal_pending(current)) |
576 | return -ERESTARTSYS; | |
5274f052 | 577 | |
b3c2d2dd MS |
578 | if (sd->need_wakeup) { |
579 | wakeup_pipe_writers(pipe); | |
580 | sd->need_wakeup = false; | |
5274f052 JA |
581 | } |
582 | ||
472e5b05 | 583 | pipe_wait_readable(pipe); |
b3c2d2dd | 584 | } |
29e35094 | 585 | |
d1a819a2 LT |
586 | if (eat_empty_buffer(pipe)) |
587 | goto repeat; | |
588 | ||
b3c2d2dd MS |
589 | return 1; |
590 | } | |
5274f052 | 591 | |
b3c2d2dd MS |
592 | /** |
593 | * splice_from_pipe_begin - start splicing from pipe | |
b80901bb | 594 | * @sd: information about the splice operation |
b3c2d2dd MS |
595 | * |
596 | * Description: | |
597 | * This function should be called before a loop containing | |
598 | * splice_from_pipe_next() and splice_from_pipe_feed() to | |
599 | * initialize the necessary fields of @sd. | |
600 | */ | |
96f9bc8f | 601 | static void splice_from_pipe_begin(struct splice_desc *sd) |
b3c2d2dd MS |
602 | { |
603 | sd->num_spliced = 0; | |
604 | sd->need_wakeup = false; | |
605 | } | |
5274f052 | 606 | |
b3c2d2dd MS |
607 | /** |
608 | * splice_from_pipe_end - finish splicing from pipe | |
609 | * @pipe: pipe to splice from | |
610 | * @sd: information about the splice operation | |
611 | * | |
612 | * Description: | |
613 | * This function will wake up pipe writers if necessary. It should | |
614 | * be called after a loop containing splice_from_pipe_next() and | |
615 | * splice_from_pipe_feed(). | |
616 | */ | |
96f9bc8f | 617 | static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
b3c2d2dd MS |
618 | { |
619 | if (sd->need_wakeup) | |
620 | wakeup_pipe_writers(pipe); | |
621 | } | |
5274f052 | 622 | |
b3c2d2dd MS |
623 | /** |
624 | * __splice_from_pipe - splice data from a pipe to given actor | |
625 | * @pipe: pipe to splice from | |
626 | * @sd: information to @actor | |
627 | * @actor: handler that splices the data | |
628 | * | |
629 | * Description: | |
630 | * This function does little more than loop over the pipe and call | |
631 | * @actor to do the actual moving of a single struct pipe_buffer to | |
2dc334f1 | 632 | * the desired destination. See pipe_to_file, pipe_to_sendmsg, or |
b3c2d2dd MS |
633 | * pipe_to_user. |
634 | * | |
635 | */ | |
636 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, | |
637 | splice_actor *actor) | |
638 | { | |
639 | int ret; | |
5274f052 | 640 | |
b3c2d2dd MS |
641 | splice_from_pipe_begin(sd); |
642 | do { | |
c2489e07 | 643 | cond_resched(); |
b3c2d2dd MS |
644 | ret = splice_from_pipe_next(pipe, sd); |
645 | if (ret > 0) | |
646 | ret = splice_from_pipe_feed(pipe, sd, actor); | |
647 | } while (ret > 0); | |
648 | splice_from_pipe_end(pipe, sd); | |
649 | ||
650 | return sd->num_spliced ? sd->num_spliced : ret; | |
5274f052 | 651 | } |
40bee44e | 652 | EXPORT_SYMBOL(__splice_from_pipe); |
5274f052 | 653 | |
932cc6d4 JA |
654 | /** |
655 | * splice_from_pipe - splice data from a pipe to a file | |
656 | * @pipe: pipe to splice from | |
657 | * @out: file to splice to | |
658 | * @ppos: position in @out | |
659 | * @len: how many bytes to splice | |
660 | * @flags: splice modifier flags | |
661 | * @actor: handler that splices the data | |
662 | * | |
663 | * Description: | |
2933970b | 664 | * See __splice_from_pipe. This function locks the pipe inode, |
932cc6d4 JA |
665 | * otherwise it's identical to __splice_from_pipe(). |
666 | * | |
667 | */ | |
6da61809 MF |
668 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
669 | loff_t *ppos, size_t len, unsigned int flags, | |
670 | splice_actor *actor) | |
671 | { | |
672 | ssize_t ret; | |
c66ab6fa JA |
673 | struct splice_desc sd = { |
674 | .total_len = len, | |
675 | .flags = flags, | |
676 | .pos = *ppos, | |
6a14b90b | 677 | .u.file = out, |
c66ab6fa | 678 | }; |
6da61809 | 679 | |
61e0d47c | 680 | pipe_lock(pipe); |
c66ab6fa | 681 | ret = __splice_from_pipe(pipe, &sd, actor); |
61e0d47c | 682 | pipe_unlock(pipe); |
6da61809 MF |
683 | |
684 | return ret; | |
685 | } | |
686 | ||
8d020765 AV |
687 | /** |
688 | * iter_file_splice_write - splice data from a pipe to a file | |
689 | * @pipe: pipe info | |
690 | * @out: file to write to | |
691 | * @ppos: position in @out | |
692 | * @len: number of bytes to splice | |
693 | * @flags: splice modifier flags | |
694 | * | |
695 | * Description: | |
696 | * Will either move or copy pages (determined by @flags options) from | |
697 | * the given pipe inode to the given file. | |
698 | * This one is ->write_iter-based. | |
699 | * | |
700 | */ | |
701 | ssize_t | |
702 | iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, | |
703 | loff_t *ppos, size_t len, unsigned int flags) | |
704 | { | |
705 | struct splice_desc sd = { | |
706 | .total_len = len, | |
707 | .flags = flags, | |
708 | .pos = *ppos, | |
709 | .u.file = out, | |
710 | }; | |
6718b6f8 | 711 | int nbufs = pipe->max_usage; |
8d020765 AV |
712 | struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), |
713 | GFP_KERNEL); | |
714 | ssize_t ret; | |
715 | ||
716 | if (unlikely(!array)) | |
717 | return -ENOMEM; | |
718 | ||
719 | pipe_lock(pipe); | |
720 | ||
721 | splice_from_pipe_begin(&sd); | |
722 | while (sd.total_len) { | |
723 | struct iov_iter from; | |
ec057595 | 724 | unsigned int head, tail, mask; |
8d020765 | 725 | size_t left; |
8cefc107 | 726 | int n; |
8d020765 AV |
727 | |
728 | ret = splice_from_pipe_next(pipe, &sd); | |
729 | if (ret <= 0) | |
730 | break; | |
731 | ||
6718b6f8 | 732 | if (unlikely(nbufs < pipe->max_usage)) { |
8d020765 | 733 | kfree(array); |
6718b6f8 | 734 | nbufs = pipe->max_usage; |
8d020765 AV |
735 | array = kcalloc(nbufs, sizeof(struct bio_vec), |
736 | GFP_KERNEL); | |
737 | if (!array) { | |
738 | ret = -ENOMEM; | |
739 | break; | |
740 | } | |
741 | } | |
742 | ||
ec057595 LT |
743 | head = pipe->head; |
744 | tail = pipe->tail; | |
745 | mask = pipe->ring_size - 1; | |
746 | ||
8d020765 AV |
747 | /* build the vector */ |
748 | left = sd.total_len; | |
0f1d344f | 749 | for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { |
8cefc107 | 750 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
8d020765 AV |
751 | size_t this_len = buf->len; |
752 | ||
0f1d344f PB |
753 | /* zero-length bvecs are not supported, skip them */ |
754 | if (!this_len) | |
755 | continue; | |
756 | this_len = min(this_len, left); | |
8d020765 | 757 | |
fba597db | 758 | ret = pipe_buf_confirm(pipe, buf); |
8d020765 AV |
759 | if (unlikely(ret)) { |
760 | if (ret == -ENODATA) | |
761 | ret = 0; | |
762 | goto done; | |
763 | } | |
764 | ||
664e4078 CH |
765 | bvec_set_page(&array[n], buf->page, this_len, |
766 | buf->offset); | |
8d020765 | 767 | left -= this_len; |
0f1d344f | 768 | n++; |
8d020765 AV |
769 | } |
770 | ||
de4eda9d | 771 | iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); |
abbb6589 | 772 | ret = vfs_iter_write(out, &from, &sd.pos, 0); |
8d020765 AV |
773 | if (ret <= 0) |
774 | break; | |
775 | ||
776 | sd.num_spliced += ret; | |
777 | sd.total_len -= ret; | |
dbe4e192 | 778 | *ppos = sd.pos; |
8d020765 AV |
779 | |
780 | /* dismiss the fully eaten buffers, adjust the partial one */ | |
8cefc107 | 781 | tail = pipe->tail; |
8d020765 | 782 | while (ret) { |
8cefc107 | 783 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
8d020765 | 784 | if (ret >= buf->len) { |
8d020765 AV |
785 | ret -= buf->len; |
786 | buf->len = 0; | |
a779638c | 787 | pipe_buf_release(pipe, buf); |
8cefc107 DH |
788 | tail++; |
789 | pipe->tail = tail; | |
8d020765 AV |
790 | if (pipe->files) |
791 | sd.need_wakeup = true; | |
792 | } else { | |
793 | buf->offset += ret; | |
794 | buf->len -= ret; | |
795 | ret = 0; | |
796 | } | |
797 | } | |
798 | } | |
799 | done: | |
800 | kfree(array); | |
801 | splice_from_pipe_end(pipe, &sd); | |
802 | ||
803 | pipe_unlock(pipe); | |
804 | ||
805 | if (sd.num_spliced) | |
806 | ret = sd.num_spliced; | |
807 | ||
808 | return ret; | |
809 | } | |
810 | ||
811 | EXPORT_SYMBOL(iter_file_splice_write); | |
812 | ||
2dc334f1 | 813 | #ifdef CONFIG_NET |
83f9135b | 814 | /** |
2dc334f1 | 815 | * splice_to_socket - splice data from a pipe to a socket |
932cc6d4 | 816 | * @pipe: pipe to splice from |
83f9135b | 817 | * @out: socket to write to |
932cc6d4 | 818 | * @ppos: position in @out |
83f9135b JA |
819 | * @len: number of bytes to splice |
820 | * @flags: splice modifier flags | |
821 | * | |
932cc6d4 JA |
822 | * Description: |
823 | * Will send @len bytes from the pipe to a network socket. No data copying | |
824 | * is involved. | |
83f9135b JA |
825 | * |
826 | */ | |
2dc334f1 DH |
827 | ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, |
828 | loff_t *ppos, size_t len, unsigned int flags) | |
5274f052 | 829 | { |
2dc334f1 DH |
830 | struct socket *sock = sock_from_file(out); |
831 | struct bio_vec bvec[16]; | |
832 | struct msghdr msg = {}; | |
833 | ssize_t ret = 0; | |
834 | size_t spliced = 0; | |
835 | bool need_wakeup = false; | |
836 | ||
837 | pipe_lock(pipe); | |
838 | ||
839 | while (len > 0) { | |
840 | unsigned int head, tail, mask, bc = 0; | |
841 | size_t remain = len; | |
842 | ||
843 | /* | |
844 | * Check for signal early to make process killable when there | |
845 | * are always buffers available | |
846 | */ | |
847 | ret = -ERESTARTSYS; | |
848 | if (signal_pending(current)) | |
849 | break; | |
850 | ||
851 | while (pipe_empty(pipe->head, pipe->tail)) { | |
852 | ret = 0; | |
853 | if (!pipe->writers) | |
854 | goto out; | |
855 | ||
856 | if (spliced) | |
857 | goto out; | |
858 | ||
859 | ret = -EAGAIN; | |
860 | if (flags & SPLICE_F_NONBLOCK) | |
861 | goto out; | |
862 | ||
863 | ret = -ERESTARTSYS; | |
864 | if (signal_pending(current)) | |
865 | goto out; | |
866 | ||
867 | if (need_wakeup) { | |
868 | wakeup_pipe_writers(pipe); | |
869 | need_wakeup = false; | |
870 | } | |
871 | ||
872 | pipe_wait_readable(pipe); | |
873 | } | |
874 | ||
875 | head = pipe->head; | |
876 | tail = pipe->tail; | |
877 | mask = pipe->ring_size - 1; | |
878 | ||
879 | while (!pipe_empty(head, tail)) { | |
880 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
881 | size_t seg; | |
882 | ||
883 | if (!buf->len) { | |
884 | tail++; | |
885 | continue; | |
886 | } | |
5274f052 | 887 | |
2dc334f1 DH |
888 | seg = min_t(size_t, remain, buf->len); |
889 | seg = min_t(size_t, seg, PAGE_SIZE); | |
890 | ||
891 | ret = pipe_buf_confirm(pipe, buf); | |
892 | if (unlikely(ret)) { | |
893 | if (ret == -ENODATA) | |
894 | ret = 0; | |
895 | break; | |
896 | } | |
897 | ||
898 | bvec_set_page(&bvec[bc++], buf->page, seg, buf->offset); | |
899 | remain -= seg; | |
900 | if (seg >= buf->len) | |
901 | tail++; | |
902 | if (bc >= ARRAY_SIZE(bvec)) | |
903 | break; | |
904 | } | |
905 | ||
906 | if (!bc) | |
907 | break; | |
908 | ||
909 | msg.msg_flags = MSG_SPLICE_PAGES; | |
910 | if (flags & SPLICE_F_MORE) | |
911 | msg.msg_flags |= MSG_MORE; | |
912 | if (remain && pipe_occupancy(pipe->head, tail) > 0) | |
913 | msg.msg_flags |= MSG_MORE; | |
914 | ||
915 | iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, bvec, bc, | |
916 | len - remain); | |
917 | ret = sock_sendmsg(sock, &msg); | |
918 | if (ret <= 0) | |
919 | break; | |
920 | ||
921 | spliced += ret; | |
922 | len -= ret; | |
923 | tail = pipe->tail; | |
924 | while (ret > 0) { | |
925 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
926 | size_t seg = min_t(size_t, ret, buf->len); | |
927 | ||
928 | buf->offset += seg; | |
929 | buf->len -= seg; | |
930 | ret -= seg; | |
931 | ||
932 | if (!buf->len) { | |
933 | pipe_buf_release(pipe, buf); | |
934 | tail++; | |
935 | } | |
936 | } | |
937 | ||
938 | if (tail != pipe->tail) { | |
939 | pipe->tail = tail; | |
940 | if (pipe->files) | |
941 | need_wakeup = true; | |
942 | } | |
943 | } | |
944 | ||
945 | out: | |
946 | pipe_unlock(pipe); | |
947 | if (need_wakeup) | |
948 | wakeup_pipe_writers(pipe); | |
949 | return spliced ?: ret; | |
950 | } | |
951 | #endif | |
a0f06780 | 952 | |
36e2c742 CH |
953 | static int warn_unsupported(struct file *file, const char *op) |
954 | { | |
955 | pr_debug_ratelimited( | |
956 | "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", | |
957 | op, file, current->pid, current->comm); | |
958 | return -EINVAL; | |
959 | } | |
960 | ||
83f9135b JA |
961 | /* |
962 | * Attempt to initiate a splice from pipe to file. | |
963 | */ | |
3a326a2c | 964 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 965 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 966 | { |
36e2c742 CH |
967 | if (unlikely(!out->f_op->splice_write)) |
968 | return warn_unsupported(out, "write"); | |
969 | return out->f_op->splice_write(pipe, out, ppos, len, flags); | |
5274f052 JA |
970 | } |
971 | ||
2bfc6685 DH |
972 | /* |
973 | * Indicate to the caller that there was a premature EOF when reading from the | |
974 | * source and the caller didn't indicate they would be sending more data after | |
975 | * this. | |
976 | */ | |
977 | static void do_splice_eof(struct splice_desc *sd) | |
978 | { | |
979 | if (sd->splice_eof) | |
980 | sd->splice_eof(sd); | |
981 | } | |
982 | ||
83f9135b JA |
983 | /* |
984 | * Attempt to initiate a splice from a file to a pipe. | |
985 | */ | |
cbb7e577 JA |
986 | static long do_splice_to(struct file *in, loff_t *ppos, |
987 | struct pipe_inode_info *pipe, size_t len, | |
988 | unsigned int flags) | |
5274f052 | 989 | { |
313d64a3 | 990 | unsigned int p_space; |
5274f052 JA |
991 | int ret; |
992 | ||
49570e9b | 993 | if (unlikely(!(in->f_mode & FMODE_READ))) |
5274f052 JA |
994 | return -EBADF; |
995 | ||
313d64a3 AV |
996 | /* Don't try to read more the pipe has space for. */ |
997 | p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); | |
998 | len = min_t(size_t, len, p_space << PAGE_SHIFT); | |
999 | ||
cbb7e577 | 1000 | ret = rw_verify_area(READ, in, ppos, len); |
5274f052 JA |
1001 | if (unlikely(ret < 0)) |
1002 | return ret; | |
1003 | ||
03cc0789 AV |
1004 | if (unlikely(len > MAX_RW_COUNT)) |
1005 | len = MAX_RW_COUNT; | |
1006 | ||
36e2c742 CH |
1007 | if (unlikely(!in->f_op->splice_read)) |
1008 | return warn_unsupported(in, "read"); | |
1009 | return in->f_op->splice_read(in, ppos, pipe, len, flags); | |
5274f052 JA |
1010 | } |
1011 | ||
932cc6d4 JA |
1012 | /** |
1013 | * splice_direct_to_actor - splices data directly between two non-pipes | |
1014 | * @in: file to splice from | |
1015 | * @sd: actor information on where to splice to | |
1016 | * @actor: handles the data splicing | |
1017 | * | |
1018 | * Description: | |
1019 | * This is a special case helper to splice directly between two | |
1020 | * points, without requiring an explicit pipe. Internally an allocated | |
79685b8d | 1021 | * pipe is cached in the process, and reused during the lifetime of |
932cc6d4 JA |
1022 | * that process. |
1023 | * | |
c66ab6fa JA |
1024 | */ |
1025 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, | |
1026 | splice_direct_actor *actor) | |
b92ce558 JA |
1027 | { |
1028 | struct pipe_inode_info *pipe; | |
1029 | long ret, bytes; | |
c66ab6fa | 1030 | size_t len; |
0ff28d9f | 1031 | int i, flags, more; |
b92ce558 JA |
1032 | |
1033 | /* | |
97ef77c5 JD |
1034 | * We require the input to be seekable, as we don't want to randomly |
1035 | * drop data for eg socket -> socket splicing. Use the piped splicing | |
1036 | * for that! | |
b92ce558 | 1037 | */ |
97ef77c5 | 1038 | if (unlikely(!(in->f_mode & FMODE_LSEEK))) |
b92ce558 JA |
1039 | return -EINVAL; |
1040 | ||
1041 | /* | |
1042 | * neither in nor out is a pipe, setup an internal pipe attached to | |
1043 | * 'out' and transfer the wanted data from 'in' to 'out' through that | |
1044 | */ | |
1045 | pipe = current->splice_pipe; | |
49570e9b | 1046 | if (unlikely(!pipe)) { |
7bee130e | 1047 | pipe = alloc_pipe_info(); |
b92ce558 JA |
1048 | if (!pipe) |
1049 | return -ENOMEM; | |
1050 | ||
1051 | /* | |
1052 | * We don't have an immediate reader, but we'll read the stuff | |
00522fb4 | 1053 | * out of the pipe right after the splice_to_pipe(). So set |
b92ce558 JA |
1054 | * PIPE_READERS appropriately. |
1055 | */ | |
1056 | pipe->readers = 1; | |
1057 | ||
1058 | current->splice_pipe = pipe; | |
1059 | } | |
1060 | ||
1061 | /* | |
73d62d83 | 1062 | * Do the splice. |
b92ce558 | 1063 | */ |
b92ce558 | 1064 | bytes = 0; |
c66ab6fa | 1065 | len = sd->total_len; |
219d9205 DH |
1066 | |
1067 | /* Don't block on output, we have to drain the direct pipe. */ | |
c66ab6fa | 1068 | flags = sd->flags; |
219d9205 | 1069 | sd->flags &= ~SPLICE_F_NONBLOCK; |
c66ab6fa JA |
1070 | |
1071 | /* | |
219d9205 DH |
1072 | * We signal MORE until we've read sufficient data to fulfill the |
1073 | * request and we keep signalling it if the caller set it. | |
c66ab6fa | 1074 | */ |
0ff28d9f | 1075 | more = sd->flags & SPLICE_F_MORE; |
219d9205 | 1076 | sd->flags |= SPLICE_F_MORE; |
b92ce558 | 1077 | |
8cefc107 | 1078 | WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); |
17614445 | 1079 | |
b92ce558 | 1080 | while (len) { |
51a92c0f | 1081 | size_t read_len; |
a82c53a0 | 1082 | loff_t pos = sd->pos, prev_pos = pos; |
b92ce558 | 1083 | |
313d64a3 | 1084 | ret = do_splice_to(in, &pos, pipe, len, flags); |
51a92c0f | 1085 | if (unlikely(ret <= 0)) |
2bfc6685 | 1086 | goto read_failure; |
b92ce558 JA |
1087 | |
1088 | read_len = ret; | |
c66ab6fa | 1089 | sd->total_len = read_len; |
b92ce558 | 1090 | |
0ff28d9f | 1091 | /* |
219d9205 DH |
1092 | * If we now have sufficient data to fulfill the request then |
1093 | * we clear SPLICE_F_MORE if it was not set initially. | |
0ff28d9f | 1094 | */ |
219d9205 | 1095 | if (read_len >= len && !more) |
0ff28d9f | 1096 | sd->flags &= ~SPLICE_F_MORE; |
219d9205 | 1097 | |
b92ce558 JA |
1098 | /* |
1099 | * NOTE: nonblocking mode only applies to the input. We | |
1100 | * must not do the output in nonblocking mode as then we | |
1101 | * could get stuck data in the internal pipe: | |
1102 | */ | |
c66ab6fa | 1103 | ret = actor(pipe, sd); |
a82c53a0 TZ |
1104 | if (unlikely(ret <= 0)) { |
1105 | sd->pos = prev_pos; | |
b92ce558 | 1106 | goto out_release; |
a82c53a0 | 1107 | } |
b92ce558 JA |
1108 | |
1109 | bytes += ret; | |
1110 | len -= ret; | |
bcd4f3ac | 1111 | sd->pos = pos; |
b92ce558 | 1112 | |
a82c53a0 TZ |
1113 | if (ret < read_len) { |
1114 | sd->pos = prev_pos + ret; | |
51a92c0f | 1115 | goto out_release; |
a82c53a0 | 1116 | } |
b92ce558 JA |
1117 | } |
1118 | ||
9e97198d | 1119 | done: |
8cefc107 | 1120 | pipe->tail = pipe->head = 0; |
80848708 | 1121 | file_accessed(in); |
b92ce558 JA |
1122 | return bytes; |
1123 | ||
2bfc6685 DH |
1124 | read_failure: |
1125 | /* | |
1126 | * If the user did *not* set SPLICE_F_MORE *and* we didn't hit that | |
1127 | * "use all of len" case that cleared SPLICE_F_MORE, *and* we did a | |
1128 | * "->splice_in()" that returned EOF (ie zero) *and* we have sent at | |
1129 | * least 1 byte *then* we will also do the ->splice_eof() call. | |
1130 | */ | |
1131 | if (ret == 0 && !more && len > 0 && bytes) | |
1132 | do_splice_eof(sd); | |
b92ce558 JA |
1133 | out_release: |
1134 | /* | |
1135 | * If we did an incomplete transfer we must release | |
1136 | * the pipe buffers in question: | |
1137 | */ | |
8cefc107 DH |
1138 | for (i = 0; i < pipe->ring_size; i++) { |
1139 | struct pipe_buffer *buf = &pipe->bufs[i]; | |
b92ce558 | 1140 | |
a779638c MS |
1141 | if (buf->ops) |
1142 | pipe_buf_release(pipe, buf); | |
b92ce558 | 1143 | } |
b92ce558 | 1144 | |
9e97198d JA |
1145 | if (!bytes) |
1146 | bytes = ret; | |
c66ab6fa | 1147 | |
9e97198d | 1148 | goto done; |
c66ab6fa JA |
1149 | } |
1150 | EXPORT_SYMBOL(splice_direct_to_actor); | |
1151 | ||
1152 | static int direct_splice_actor(struct pipe_inode_info *pipe, | |
1153 | struct splice_desc *sd) | |
1154 | { | |
6a14b90b | 1155 | struct file *file = sd->u.file; |
c66ab6fa | 1156 | |
7995bd28 | 1157 | return do_splice_from(pipe, file, sd->opos, sd->total_len, |
2cb4b05e | 1158 | sd->flags); |
c66ab6fa JA |
1159 | } |
1160 | ||
2bfc6685 DH |
1161 | static void direct_file_splice_eof(struct splice_desc *sd) |
1162 | { | |
1163 | struct file *file = sd->u.file; | |
1164 | ||
1165 | if (file->f_op->splice_eof) | |
1166 | file->f_op->splice_eof(file); | |
1167 | } | |
1168 | ||
932cc6d4 JA |
1169 | /** |
1170 | * do_splice_direct - splices data directly between two files | |
1171 | * @in: file to splice from | |
1172 | * @ppos: input file offset | |
1173 | * @out: file to splice to | |
acdb37c3 | 1174 | * @opos: output file offset |
932cc6d4 JA |
1175 | * @len: number of bytes to splice |
1176 | * @flags: splice modifier flags | |
1177 | * | |
1178 | * Description: | |
1179 | * For use by do_sendfile(). splice can easily emulate sendfile, but | |
1180 | * doing it in the application would incur an extra system call | |
1181 | * (splice in + splice out, as compared to just sendfile()). So this helper | |
1182 | * can splice directly through a process-private pipe. | |
1183 | * | |
1184 | */ | |
c66ab6fa | 1185 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
7995bd28 | 1186 | loff_t *opos, size_t len, unsigned int flags) |
c66ab6fa JA |
1187 | { |
1188 | struct splice_desc sd = { | |
1189 | .len = len, | |
1190 | .total_len = len, | |
1191 | .flags = flags, | |
1192 | .pos = *ppos, | |
6a14b90b | 1193 | .u.file = out, |
2bfc6685 | 1194 | .splice_eof = direct_file_splice_eof, |
7995bd28 | 1195 | .opos = opos, |
c66ab6fa | 1196 | }; |
51a92c0f | 1197 | long ret; |
c66ab6fa | 1198 | |
18c67cb9 AV |
1199 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
1200 | return -EBADF; | |
1201 | ||
1202 | if (unlikely(out->f_flags & O_APPEND)) | |
1203 | return -EINVAL; | |
1204 | ||
1205 | ret = rw_verify_area(WRITE, out, opos, len); | |
1206 | if (unlikely(ret < 0)) | |
1207 | return ret; | |
1208 | ||
c66ab6fa | 1209 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
51a92c0f | 1210 | if (ret > 0) |
a82c53a0 | 1211 | *ppos = sd.pos; |
51a92c0f | 1212 | |
c66ab6fa | 1213 | return ret; |
b92ce558 | 1214 | } |
1c118596 | 1215 | EXPORT_SYMBOL(do_splice_direct); |
b92ce558 | 1216 | |
8924feff AV |
1217 | static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) |
1218 | { | |
52bce911 LT |
1219 | for (;;) { |
1220 | if (unlikely(!pipe->readers)) { | |
1221 | send_sig(SIGPIPE, current, 0); | |
1222 | return -EPIPE; | |
1223 | } | |
6718b6f8 | 1224 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
52bce911 | 1225 | return 0; |
8924feff AV |
1226 | if (flags & SPLICE_F_NONBLOCK) |
1227 | return -EAGAIN; | |
1228 | if (signal_pending(current)) | |
1229 | return -ERESTARTSYS; | |
472e5b05 | 1230 | pipe_wait_writable(pipe); |
8924feff | 1231 | } |
8924feff AV |
1232 | } |
1233 | ||
7c77f0b3 MS |
1234 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
1235 | struct pipe_inode_info *opipe, | |
1236 | size_t len, unsigned int flags); | |
ddac0d39 | 1237 | |
b964bf53 | 1238 | long splice_file_to_pipe(struct file *in, |
faa97c48 AV |
1239 | struct pipe_inode_info *opipe, |
1240 | loff_t *offset, | |
1241 | size_t len, unsigned int flags) | |
1242 | { | |
1243 | long ret; | |
1244 | ||
1245 | pipe_lock(opipe); | |
1246 | ret = wait_for_space(opipe, flags); | |
1247 | if (!ret) | |
1248 | ret = do_splice_to(in, offset, opipe, len, flags); | |
1249 | pipe_unlock(opipe); | |
1250 | if (ret > 0) | |
1251 | wakeup_pipe_readers(opipe); | |
1252 | return ret; | |
1253 | } | |
1254 | ||
83f9135b JA |
1255 | /* |
1256 | * Determine where to splice to/from. | |
1257 | */ | |
ee6e00c8 JA |
1258 | long do_splice(struct file *in, loff_t *off_in, struct file *out, |
1259 | loff_t *off_out, size_t len, unsigned int flags) | |
5274f052 | 1260 | { |
7c77f0b3 MS |
1261 | struct pipe_inode_info *ipipe; |
1262 | struct pipe_inode_info *opipe; | |
7995bd28 | 1263 | loff_t offset; |
a4514ebd | 1264 | long ret; |
5274f052 | 1265 | |
90da2e3f PB |
1266 | if (unlikely(!(in->f_mode & FMODE_READ) || |
1267 | !(out->f_mode & FMODE_WRITE))) | |
1268 | return -EBADF; | |
1269 | ||
c73be61c DH |
1270 | ipipe = get_pipe_info(in, true); |
1271 | opipe = get_pipe_info(out, true); | |
7c77f0b3 MS |
1272 | |
1273 | if (ipipe && opipe) { | |
1274 | if (off_in || off_out) | |
1275 | return -ESPIPE; | |
1276 | ||
7c77f0b3 MS |
1277 | /* Splicing to self would be fun, but... */ |
1278 | if (ipipe == opipe) | |
1279 | return -EINVAL; | |
1280 | ||
ee5e0011 SK |
1281 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
1282 | flags |= SPLICE_F_NONBLOCK; | |
1283 | ||
7c77f0b3 MS |
1284 | return splice_pipe_to_pipe(ipipe, opipe, len, flags); |
1285 | } | |
1286 | ||
1287 | if (ipipe) { | |
529565dc IM |
1288 | if (off_in) |
1289 | return -ESPIPE; | |
b92ce558 | 1290 | if (off_out) { |
19c9a49b | 1291 | if (!(out->f_mode & FMODE_PWRITE)) |
b92ce558 | 1292 | return -EINVAL; |
ee6e00c8 | 1293 | offset = *off_out; |
7995bd28 AV |
1294 | } else { |
1295 | offset = out->f_pos; | |
1296 | } | |
529565dc | 1297 | |
18c67cb9 AV |
1298 | if (unlikely(out->f_flags & O_APPEND)) |
1299 | return -EINVAL; | |
1300 | ||
1301 | ret = rw_verify_area(WRITE, out, &offset, len); | |
1302 | if (unlikely(ret < 0)) | |
1303 | return ret; | |
1304 | ||
ee5e0011 SK |
1305 | if (in->f_flags & O_NONBLOCK) |
1306 | flags |= SPLICE_F_NONBLOCK; | |
1307 | ||
500368f7 | 1308 | file_start_write(out); |
7995bd28 | 1309 | ret = do_splice_from(ipipe, out, &offset, len, flags); |
500368f7 | 1310 | file_end_write(out); |
a4514ebd | 1311 | |
983652c6 CCC |
1312 | if (ret > 0) |
1313 | fsnotify_modify(out); | |
1314 | ||
7995bd28 AV |
1315 | if (!off_out) |
1316 | out->f_pos = offset; | |
ee6e00c8 JA |
1317 | else |
1318 | *off_out = offset; | |
a4514ebd JA |
1319 | |
1320 | return ret; | |
529565dc | 1321 | } |
5274f052 | 1322 | |
7c77f0b3 | 1323 | if (opipe) { |
529565dc IM |
1324 | if (off_out) |
1325 | return -ESPIPE; | |
b92ce558 | 1326 | if (off_in) { |
19c9a49b | 1327 | if (!(in->f_mode & FMODE_PREAD)) |
b92ce558 | 1328 | return -EINVAL; |
ee6e00c8 | 1329 | offset = *off_in; |
7995bd28 AV |
1330 | } else { |
1331 | offset = in->f_pos; | |
1332 | } | |
529565dc | 1333 | |
ee5e0011 SK |
1334 | if (out->f_flags & O_NONBLOCK) |
1335 | flags |= SPLICE_F_NONBLOCK; | |
1336 | ||
faa97c48 | 1337 | ret = splice_file_to_pipe(in, opipe, &offset, len, flags); |
983652c6 CCC |
1338 | |
1339 | if (ret > 0) | |
1340 | fsnotify_access(in); | |
1341 | ||
7995bd28 AV |
1342 | if (!off_in) |
1343 | in->f_pos = offset; | |
ee6e00c8 JA |
1344 | else |
1345 | *off_in = offset; | |
a4514ebd JA |
1346 | |
1347 | return ret; | |
529565dc | 1348 | } |
5274f052 JA |
1349 | |
1350 | return -EINVAL; | |
1351 | } | |
1352 | ||
ee6e00c8 JA |
1353 | static long __do_splice(struct file *in, loff_t __user *off_in, |
1354 | struct file *out, loff_t __user *off_out, | |
1355 | size_t len, unsigned int flags) | |
1356 | { | |
1357 | struct pipe_inode_info *ipipe; | |
1358 | struct pipe_inode_info *opipe; | |
1359 | loff_t offset, *__off_in = NULL, *__off_out = NULL; | |
1360 | long ret; | |
1361 | ||
1362 | ipipe = get_pipe_info(in, true); | |
1363 | opipe = get_pipe_info(out, true); | |
1364 | ||
0f99fc51 JA |
1365 | if (ipipe) { |
1366 | if (off_in) | |
1367 | return -ESPIPE; | |
1368 | pipe_clear_nowait(in); | |
1369 | } | |
1370 | if (opipe) { | |
1371 | if (off_out) | |
1372 | return -ESPIPE; | |
1373 | pipe_clear_nowait(out); | |
1374 | } | |
ee6e00c8 JA |
1375 | |
1376 | if (off_out) { | |
1377 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) | |
1378 | return -EFAULT; | |
1379 | __off_out = &offset; | |
1380 | } | |
1381 | if (off_in) { | |
1382 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) | |
1383 | return -EFAULT; | |
1384 | __off_in = &offset; | |
1385 | } | |
1386 | ||
1387 | ret = do_splice(in, __off_in, out, __off_out, len, flags); | |
1388 | if (ret < 0) | |
1389 | return ret; | |
1390 | ||
1391 | if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) | |
1392 | return -EFAULT; | |
1393 | if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) | |
1394 | return -EFAULT; | |
1395 | ||
1396 | return ret; | |
1397 | } | |
1398 | ||
79fddc4e AV |
1399 | static int iter_to_pipe(struct iov_iter *from, |
1400 | struct pipe_inode_info *pipe, | |
1401 | unsigned flags) | |
912d35f8 | 1402 | { |
79fddc4e AV |
1403 | struct pipe_buffer buf = { |
1404 | .ops = &user_page_pipe_buf_ops, | |
1405 | .flags = flags | |
1406 | }; | |
1407 | size_t total = 0; | |
1408 | int ret = 0; | |
79fddc4e | 1409 | |
7d690c15 | 1410 | while (iov_iter_count(from)) { |
79fddc4e | 1411 | struct page *pages[16]; |
7d690c15 | 1412 | ssize_t left; |
db85a9eb | 1413 | size_t start; |
7d690c15 | 1414 | int i, n; |
db85a9eb | 1415 | |
7d690c15 AV |
1416 | left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); |
1417 | if (left <= 0) { | |
1418 | ret = left; | |
79fddc4e AV |
1419 | break; |
1420 | } | |
db85a9eb | 1421 | |
7d690c15 AV |
1422 | n = DIV_ROUND_UP(left + start, PAGE_SIZE); |
1423 | for (i = 0; i < n; i++) { | |
1424 | int size = min_t(int, left, PAGE_SIZE - start); | |
1425 | ||
1426 | buf.page = pages[i]; | |
1427 | buf.offset = start; | |
1428 | buf.len = size; | |
1429 | ret = add_to_pipe(pipe, &buf); | |
1430 | if (unlikely(ret < 0)) { | |
1431 | iov_iter_revert(from, left); | |
1432 | // this one got dropped by add_to_pipe() | |
1433 | while (++i < n) | |
1434 | put_page(pages[i]); | |
1435 | goto out; | |
79fddc4e | 1436 | } |
7d690c15 AV |
1437 | total += ret; |
1438 | left -= size; | |
1439 | start = 0; | |
912d35f8 | 1440 | } |
912d35f8 | 1441 | } |
7d690c15 | 1442 | out: |
79fddc4e | 1443 | return total ? total : ret; |
912d35f8 JA |
1444 | } |
1445 | ||
6a14b90b JA |
1446 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
1447 | struct splice_desc *sd) | |
1448 | { | |
6130f531 AV |
1449 | int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); |
1450 | return n == sd->len ? n : -EFAULT; | |
6a14b90b JA |
1451 | } |
1452 | ||
1453 | /* | |
1454 | * For lack of a better implementation, implement vmsplice() to userspace | |
1455 | * as a simple copy of the pipes pages to the user iov. | |
1456 | */ | |
87a3002a AV |
1457 | static long vmsplice_to_user(struct file *file, struct iov_iter *iter, |
1458 | unsigned int flags) | |
6a14b90b | 1459 | { |
c73be61c | 1460 | struct pipe_inode_info *pipe = get_pipe_info(file, true); |
87a3002a AV |
1461 | struct splice_desc sd = { |
1462 | .total_len = iov_iter_count(iter), | |
1463 | .flags = flags, | |
1464 | .u.data = iter | |
1465 | }; | |
1466 | long ret = 0; | |
6a14b90b | 1467 | |
6a14b90b JA |
1468 | if (!pipe) |
1469 | return -EBADF; | |
1470 | ||
0f99fc51 JA |
1471 | pipe_clear_nowait(file); |
1472 | ||
345995fa AV |
1473 | if (sd.total_len) { |
1474 | pipe_lock(pipe); | |
1475 | ret = __splice_from_pipe(pipe, &sd, pipe_to_user); | |
1476 | pipe_unlock(pipe); | |
1477 | } | |
6a14b90b JA |
1478 | |
1479 | return ret; | |
1480 | } | |
1481 | ||
912d35f8 JA |
1482 | /* |
1483 | * vmsplice splices a user address range into a pipe. It can be thought of | |
1484 | * as splice-from-memory, where the regular splice is splice-from-file (or | |
1485 | * to file). In both cases the output is a pipe, naturally. | |
912d35f8 | 1486 | */ |
87a3002a AV |
1487 | static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, |
1488 | unsigned int flags) | |
912d35f8 | 1489 | { |
ddac0d39 | 1490 | struct pipe_inode_info *pipe; |
87a3002a | 1491 | long ret = 0; |
79fddc4e AV |
1492 | unsigned buf_flag = 0; |
1493 | ||
1494 | if (flags & SPLICE_F_GIFT) | |
1495 | buf_flag = PIPE_BUF_FLAG_GIFT; | |
912d35f8 | 1496 | |
c73be61c | 1497 | pipe = get_pipe_info(file, true); |
ddac0d39 | 1498 | if (!pipe) |
912d35f8 | 1499 | return -EBADF; |
912d35f8 | 1500 | |
0f99fc51 JA |
1501 | pipe_clear_nowait(file); |
1502 | ||
8924feff AV |
1503 | pipe_lock(pipe); |
1504 | ret = wait_for_space(pipe, flags); | |
79fddc4e | 1505 | if (!ret) |
87a3002a | 1506 | ret = iter_to_pipe(iter, pipe, buf_flag); |
8924feff AV |
1507 | pipe_unlock(pipe); |
1508 | if (ret > 0) | |
1509 | wakeup_pipe_readers(pipe); | |
35f3d14d | 1510 | return ret; |
912d35f8 JA |
1511 | } |
1512 | ||
87a3002a AV |
1513 | static int vmsplice_type(struct fd f, int *type) |
1514 | { | |
1515 | if (!f.file) | |
1516 | return -EBADF; | |
1517 | if (f.file->f_mode & FMODE_WRITE) { | |
de4eda9d | 1518 | *type = ITER_SOURCE; |
87a3002a | 1519 | } else if (f.file->f_mode & FMODE_READ) { |
de4eda9d | 1520 | *type = ITER_DEST; |
87a3002a AV |
1521 | } else { |
1522 | fdput(f); | |
1523 | return -EBADF; | |
1524 | } | |
1525 | return 0; | |
1526 | } | |
1527 | ||
6a14b90b JA |
1528 | /* |
1529 | * Note that vmsplice only really supports true splicing _from_ user memory | |
1530 | * to a pipe, not the other way around. Splicing from user memory is a simple | |
1531 | * operation that can be supported without any funky alignment restrictions | |
1532 | * or nasty vm tricks. We simply map in the user memory and fill them into | |
1533 | * a pipe. The reverse isn't quite as easy, though. There are two possible | |
1534 | * solutions for that: | |
1535 | * | |
1536 | * - memcpy() the data internally, at which point we might as well just | |
1537 | * do a regular read() on the buffer anyway. | |
1538 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it | |
1539 | * has restriction limitations on both ends of the pipe). | |
1540 | * | |
1541 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). | |
1542 | * | |
1543 | */ | |
87a3002a | 1544 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, |
30cfe4ef DB |
1545 | unsigned long, nr_segs, unsigned int, flags) |
1546 | { | |
87a3002a AV |
1547 | struct iovec iovstack[UIO_FASTIOV]; |
1548 | struct iovec *iov = iovstack; | |
1549 | struct iov_iter iter; | |
87e5e6da | 1550 | ssize_t error; |
87a3002a AV |
1551 | struct fd f; |
1552 | int type; | |
1553 | ||
598b3cec CH |
1554 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1555 | return -EINVAL; | |
1556 | ||
87a3002a AV |
1557 | f = fdget(fd); |
1558 | error = vmsplice_type(f, &type); | |
1559 | if (error) | |
1560 | return error; | |
1561 | ||
1562 | error = import_iovec(type, uiov, nr_segs, | |
1563 | ARRAY_SIZE(iovstack), &iov, &iter); | |
598b3cec CH |
1564 | if (error < 0) |
1565 | goto out_fdput; | |
30cfe4ef | 1566 | |
598b3cec CH |
1567 | if (!iov_iter_count(&iter)) |
1568 | error = 0; | |
de4eda9d | 1569 | else if (type == ITER_SOURCE) |
598b3cec CH |
1570 | error = vmsplice_to_pipe(f.file, &iter, flags); |
1571 | else | |
1572 | error = vmsplice_to_user(f.file, &iter, flags); | |
87a3002a | 1573 | |
598b3cec CH |
1574 | kfree(iov); |
1575 | out_fdput: | |
87a3002a AV |
1576 | fdput(f); |
1577 | return error; | |
76b021d0 | 1578 | } |
76b021d0 | 1579 | |
836f92ad HC |
1580 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
1581 | int, fd_out, loff_t __user *, off_out, | |
1582 | size_t, len, unsigned int, flags) | |
5274f052 | 1583 | { |
2903ff01 | 1584 | struct fd in, out; |
5274f052 | 1585 | long error; |
5274f052 JA |
1586 | |
1587 | if (unlikely(!len)) | |
1588 | return 0; | |
1589 | ||
3d6ea290 AV |
1590 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1591 | return -EINVAL; | |
1592 | ||
5274f052 | 1593 | error = -EBADF; |
2903ff01 AV |
1594 | in = fdget(fd_in); |
1595 | if (in.file) { | |
90da2e3f PB |
1596 | out = fdget(fd_out); |
1597 | if (out.file) { | |
ee6e00c8 JA |
1598 | error = __do_splice(in.file, off_in, out.file, off_out, |
1599 | len, flags); | |
90da2e3f | 1600 | fdput(out); |
5274f052 | 1601 | } |
2903ff01 | 1602 | fdput(in); |
5274f052 | 1603 | } |
5274f052 JA |
1604 | return error; |
1605 | } | |
70524490 | 1606 | |
aadd06e5 JA |
1607 | /* |
1608 | * Make sure there's data to read. Wait for input if we can, otherwise | |
1609 | * return an appropriate error. | |
1610 | */ | |
7c77f0b3 | 1611 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
aadd06e5 JA |
1612 | { |
1613 | int ret; | |
1614 | ||
1615 | /* | |
8cefc107 | 1616 | * Check the pipe occupancy without the inode lock first. This function |
aadd06e5 JA |
1617 | * is speculative anyways, so missing one is ok. |
1618 | */ | |
8cefc107 | 1619 | if (!pipe_empty(pipe->head, pipe->tail)) |
aadd06e5 JA |
1620 | return 0; |
1621 | ||
1622 | ret = 0; | |
61e0d47c | 1623 | pipe_lock(pipe); |
aadd06e5 | 1624 | |
8cefc107 | 1625 | while (pipe_empty(pipe->head, pipe->tail)) { |
aadd06e5 JA |
1626 | if (signal_pending(current)) { |
1627 | ret = -ERESTARTSYS; | |
1628 | break; | |
1629 | } | |
1630 | if (!pipe->writers) | |
1631 | break; | |
a28c8b9d LT |
1632 | if (flags & SPLICE_F_NONBLOCK) { |
1633 | ret = -EAGAIN; | |
1634 | break; | |
aadd06e5 | 1635 | } |
472e5b05 | 1636 | pipe_wait_readable(pipe); |
aadd06e5 JA |
1637 | } |
1638 | ||
61e0d47c | 1639 | pipe_unlock(pipe); |
aadd06e5 JA |
1640 | return ret; |
1641 | } | |
1642 | ||
1643 | /* | |
1644 | * Make sure there's writeable room. Wait for room if we can, otherwise | |
1645 | * return an appropriate error. | |
1646 | */ | |
7c77f0b3 | 1647 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
aadd06e5 JA |
1648 | { |
1649 | int ret; | |
1650 | ||
1651 | /* | |
8cefc107 | 1652 | * Check pipe occupancy without the inode lock first. This function |
aadd06e5 JA |
1653 | * is speculative anyways, so missing one is ok. |
1654 | */ | |
566d1362 | 1655 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
aadd06e5 JA |
1656 | return 0; |
1657 | ||
1658 | ret = 0; | |
61e0d47c | 1659 | pipe_lock(pipe); |
aadd06e5 | 1660 | |
6718b6f8 | 1661 | while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { |
aadd06e5 JA |
1662 | if (!pipe->readers) { |
1663 | send_sig(SIGPIPE, current, 0); | |
1664 | ret = -EPIPE; | |
1665 | break; | |
1666 | } | |
1667 | if (flags & SPLICE_F_NONBLOCK) { | |
1668 | ret = -EAGAIN; | |
1669 | break; | |
1670 | } | |
1671 | if (signal_pending(current)) { | |
1672 | ret = -ERESTARTSYS; | |
1673 | break; | |
1674 | } | |
472e5b05 | 1675 | pipe_wait_writable(pipe); |
aadd06e5 JA |
1676 | } |
1677 | ||
61e0d47c | 1678 | pipe_unlock(pipe); |
aadd06e5 JA |
1679 | return ret; |
1680 | } | |
1681 | ||
7c77f0b3 MS |
1682 | /* |
1683 | * Splice contents of ipipe to opipe. | |
1684 | */ | |
1685 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, | |
1686 | struct pipe_inode_info *opipe, | |
1687 | size_t len, unsigned int flags) | |
1688 | { | |
1689 | struct pipe_buffer *ibuf, *obuf; | |
8cefc107 DH |
1690 | unsigned int i_head, o_head; |
1691 | unsigned int i_tail, o_tail; | |
1692 | unsigned int i_mask, o_mask; | |
1693 | int ret = 0; | |
7c77f0b3 MS |
1694 | bool input_wakeup = false; |
1695 | ||
1696 | ||
1697 | retry: | |
1698 | ret = ipipe_prep(ipipe, flags); | |
1699 | if (ret) | |
1700 | return ret; | |
1701 | ||
1702 | ret = opipe_prep(opipe, flags); | |
1703 | if (ret) | |
1704 | return ret; | |
1705 | ||
1706 | /* | |
1707 | * Potential ABBA deadlock, work around it by ordering lock | |
1708 | * grabbing by pipe info address. Otherwise two different processes | |
1709 | * could deadlock (one doing tee from A -> B, the other from B -> A). | |
1710 | */ | |
1711 | pipe_double_lock(ipipe, opipe); | |
1712 | ||
8cefc107 DH |
1713 | i_tail = ipipe->tail; |
1714 | i_mask = ipipe->ring_size - 1; | |
1715 | o_head = opipe->head; | |
1716 | o_mask = opipe->ring_size - 1; | |
1717 | ||
7c77f0b3 | 1718 | do { |
8cefc107 DH |
1719 | size_t o_len; |
1720 | ||
7c77f0b3 MS |
1721 | if (!opipe->readers) { |
1722 | send_sig(SIGPIPE, current, 0); | |
1723 | if (!ret) | |
1724 | ret = -EPIPE; | |
1725 | break; | |
1726 | } | |
1727 | ||
8cefc107 DH |
1728 | i_head = ipipe->head; |
1729 | o_tail = opipe->tail; | |
1730 | ||
1731 | if (pipe_empty(i_head, i_tail) && !ipipe->writers) | |
7c77f0b3 MS |
1732 | break; |
1733 | ||
1734 | /* | |
1735 | * Cannot make any progress, because either the input | |
1736 | * pipe is empty or the output pipe is full. | |
1737 | */ | |
8cefc107 | 1738 | if (pipe_empty(i_head, i_tail) || |
6718b6f8 | 1739 | pipe_full(o_head, o_tail, opipe->max_usage)) { |
7c77f0b3 MS |
1740 | /* Already processed some buffers, break */ |
1741 | if (ret) | |
1742 | break; | |
1743 | ||
1744 | if (flags & SPLICE_F_NONBLOCK) { | |
1745 | ret = -EAGAIN; | |
1746 | break; | |
1747 | } | |
1748 | ||
1749 | /* | |
1750 | * We raced with another reader/writer and haven't | |
1751 | * managed to process any buffers. A zero return | |
1752 | * value means EOF, so retry instead. | |
1753 | */ | |
1754 | pipe_unlock(ipipe); | |
1755 | pipe_unlock(opipe); | |
1756 | goto retry; | |
1757 | } | |
1758 | ||
8cefc107 DH |
1759 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
1760 | obuf = &opipe->bufs[o_head & o_mask]; | |
7c77f0b3 MS |
1761 | |
1762 | if (len >= ibuf->len) { | |
1763 | /* | |
1764 | * Simply move the whole buffer from ipipe to opipe | |
1765 | */ | |
1766 | *obuf = *ibuf; | |
1767 | ibuf->ops = NULL; | |
8cefc107 DH |
1768 | i_tail++; |
1769 | ipipe->tail = i_tail; | |
7c77f0b3 | 1770 | input_wakeup = true; |
8cefc107 DH |
1771 | o_len = obuf->len; |
1772 | o_head++; | |
1773 | opipe->head = o_head; | |
7c77f0b3 MS |
1774 | } else { |
1775 | /* | |
1776 | * Get a reference to this pipe buffer, | |
1777 | * so we can copy the contents over. | |
1778 | */ | |
15fab63e MW |
1779 | if (!pipe_buf_get(ipipe, ibuf)) { |
1780 | if (ret == 0) | |
1781 | ret = -EFAULT; | |
1782 | break; | |
1783 | } | |
7c77f0b3 MS |
1784 | *obuf = *ibuf; |
1785 | ||
1786 | /* | |
f6dd9755 | 1787 | * Don't inherit the gift and merge flags, we need to |
7c77f0b3 MS |
1788 | * prevent multiple steals of this page. |
1789 | */ | |
1790 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; | |
f6dd9755 | 1791 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
a0ce2f0a | 1792 | |
7c77f0b3 | 1793 | obuf->len = len; |
8cefc107 DH |
1794 | ibuf->offset += len; |
1795 | ibuf->len -= len; | |
1796 | o_len = len; | |
1797 | o_head++; | |
1798 | opipe->head = o_head; | |
7c77f0b3 | 1799 | } |
8cefc107 DH |
1800 | ret += o_len; |
1801 | len -= o_len; | |
7c77f0b3 MS |
1802 | } while (len); |
1803 | ||
1804 | pipe_unlock(ipipe); | |
1805 | pipe_unlock(opipe); | |
1806 | ||
1807 | /* | |
1808 | * If we put data in the output pipe, wakeup any potential readers. | |
1809 | */ | |
825cdcb1 NK |
1810 | if (ret > 0) |
1811 | wakeup_pipe_readers(opipe); | |
1812 | ||
7c77f0b3 MS |
1813 | if (input_wakeup) |
1814 | wakeup_pipe_writers(ipipe); | |
1815 | ||
1816 | return ret; | |
1817 | } | |
1818 | ||
70524490 JA |
1819 | /* |
1820 | * Link contents of ipipe to opipe. | |
1821 | */ | |
1822 | static int link_pipe(struct pipe_inode_info *ipipe, | |
1823 | struct pipe_inode_info *opipe, | |
1824 | size_t len, unsigned int flags) | |
1825 | { | |
1826 | struct pipe_buffer *ibuf, *obuf; | |
8cefc107 DH |
1827 | unsigned int i_head, o_head; |
1828 | unsigned int i_tail, o_tail; | |
1829 | unsigned int i_mask, o_mask; | |
1830 | int ret = 0; | |
70524490 JA |
1831 | |
1832 | /* | |
1833 | * Potential ABBA deadlock, work around it by ordering lock | |
61e0d47c | 1834 | * grabbing by pipe info address. Otherwise two different processes |
70524490 JA |
1835 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
1836 | */ | |
61e0d47c | 1837 | pipe_double_lock(ipipe, opipe); |
70524490 | 1838 | |
8cefc107 DH |
1839 | i_tail = ipipe->tail; |
1840 | i_mask = ipipe->ring_size - 1; | |
1841 | o_head = opipe->head; | |
1842 | o_mask = opipe->ring_size - 1; | |
1843 | ||
aadd06e5 | 1844 | do { |
70524490 JA |
1845 | if (!opipe->readers) { |
1846 | send_sig(SIGPIPE, current, 0); | |
1847 | if (!ret) | |
1848 | ret = -EPIPE; | |
1849 | break; | |
1850 | } | |
70524490 | 1851 | |
8cefc107 DH |
1852 | i_head = ipipe->head; |
1853 | o_tail = opipe->tail; | |
1854 | ||
aadd06e5 | 1855 | /* |
8cefc107 | 1856 | * If we have iterated all input buffers or run out of |
aadd06e5 JA |
1857 | * output room, break. |
1858 | */ | |
8cefc107 | 1859 | if (pipe_empty(i_head, i_tail) || |
6718b6f8 | 1860 | pipe_full(o_head, o_tail, opipe->max_usage)) |
aadd06e5 | 1861 | break; |
70524490 | 1862 | |
8cefc107 DH |
1863 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
1864 | obuf = &opipe->bufs[o_head & o_mask]; | |
70524490 JA |
1865 | |
1866 | /* | |
aadd06e5 JA |
1867 | * Get a reference to this pipe buffer, |
1868 | * so we can copy the contents over. | |
70524490 | 1869 | */ |
15fab63e MW |
1870 | if (!pipe_buf_get(ipipe, ibuf)) { |
1871 | if (ret == 0) | |
1872 | ret = -EFAULT; | |
1873 | break; | |
1874 | } | |
aadd06e5 | 1875 | |
aadd06e5 JA |
1876 | *obuf = *ibuf; |
1877 | ||
2a27250e | 1878 | /* |
f6dd9755 CH |
1879 | * Don't inherit the gift and merge flag, we need to prevent |
1880 | * multiple steals of this page. | |
2a27250e | 1881 | */ |
aadd06e5 | 1882 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
f6dd9755 | 1883 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
a0ce2f0a | 1884 | |
aadd06e5 JA |
1885 | if (obuf->len > len) |
1886 | obuf->len = len; | |
aadd06e5 JA |
1887 | ret += obuf->len; |
1888 | len -= obuf->len; | |
8cefc107 DH |
1889 | |
1890 | o_head++; | |
1891 | opipe->head = o_head; | |
1892 | i_tail++; | |
aadd06e5 | 1893 | } while (len); |
70524490 | 1894 | |
61e0d47c MS |
1895 | pipe_unlock(ipipe); |
1896 | pipe_unlock(opipe); | |
70524490 | 1897 | |
aadd06e5 JA |
1898 | /* |
1899 | * If we put data in the output pipe, wakeup any potential readers. | |
1900 | */ | |
825cdcb1 NK |
1901 | if (ret > 0) |
1902 | wakeup_pipe_readers(opipe); | |
70524490 JA |
1903 | |
1904 | return ret; | |
1905 | } | |
1906 | ||
1907 | /* | |
1908 | * This is a tee(1) implementation that works on pipes. It doesn't copy | |
1909 | * any data, it simply references the 'in' pages on the 'out' pipe. | |
1910 | * The 'flags' used are the SPLICE_F_* variants, currently the only | |
1911 | * applicable one is SPLICE_F_NONBLOCK. | |
1912 | */ | |
9dafdfc2 | 1913 | long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) |
70524490 | 1914 | { |
c73be61c DH |
1915 | struct pipe_inode_info *ipipe = get_pipe_info(in, true); |
1916 | struct pipe_inode_info *opipe = get_pipe_info(out, true); | |
aadd06e5 | 1917 | int ret = -EINVAL; |
70524490 | 1918 | |
90da2e3f PB |
1919 | if (unlikely(!(in->f_mode & FMODE_READ) || |
1920 | !(out->f_mode & FMODE_WRITE))) | |
1921 | return -EBADF; | |
1922 | ||
70524490 | 1923 | /* |
aadd06e5 JA |
1924 | * Duplicate the contents of ipipe to opipe without actually |
1925 | * copying the data. | |
70524490 | 1926 | */ |
aadd06e5 | 1927 | if (ipipe && opipe && ipipe != opipe) { |
ee5e0011 SK |
1928 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
1929 | flags |= SPLICE_F_NONBLOCK; | |
1930 | ||
aadd06e5 JA |
1931 | /* |
1932 | * Keep going, unless we encounter an error. The ipipe/opipe | |
1933 | * ordering doesn't really matter. | |
1934 | */ | |
7c77f0b3 | 1935 | ret = ipipe_prep(ipipe, flags); |
aadd06e5 | 1936 | if (!ret) { |
7c77f0b3 | 1937 | ret = opipe_prep(opipe, flags); |
02cf01ae | 1938 | if (!ret) |
aadd06e5 | 1939 | ret = link_pipe(ipipe, opipe, len, flags); |
aadd06e5 JA |
1940 | } |
1941 | } | |
70524490 | 1942 | |
aadd06e5 | 1943 | return ret; |
70524490 JA |
1944 | } |
1945 | ||
836f92ad | 1946 | SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) |
70524490 | 1947 | { |
90da2e3f | 1948 | struct fd in, out; |
2903ff01 | 1949 | int error; |
70524490 | 1950 | |
3d6ea290 AV |
1951 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1952 | return -EINVAL; | |
1953 | ||
70524490 JA |
1954 | if (unlikely(!len)) |
1955 | return 0; | |
1956 | ||
1957 | error = -EBADF; | |
2903ff01 AV |
1958 | in = fdget(fdin); |
1959 | if (in.file) { | |
90da2e3f PB |
1960 | out = fdget(fdout); |
1961 | if (out.file) { | |
1962 | error = do_tee(in.file, out.file, len, flags); | |
1963 | fdput(out); | |
70524490 | 1964 | } |
2903ff01 | 1965 | fdput(in); |
70524490 JA |
1966 | } |
1967 | ||
1968 | return error; | |
1969 | } |