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 | 122 | { |
781ca602 | 123 | struct folio *folio = page_folio(buf->page); |
49d0b21b | 124 | int err; |
5274f052 | 125 | |
781ca602 MWO |
126 | if (!folio_test_uptodate(folio)) { |
127 | folio_lock(folio); | |
49d0b21b JA |
128 | |
129 | /* | |
781ca602 | 130 | * Folio got truncated/unhashed. This will cause a 0-byte |
73d62d83 | 131 | * splice, if this is the first page. |
49d0b21b | 132 | */ |
781ca602 | 133 | if (!folio->mapping) { |
49d0b21b JA |
134 | err = -ENODATA; |
135 | goto error; | |
136 | } | |
5274f052 | 137 | |
49d0b21b | 138 | /* |
73d62d83 | 139 | * Uh oh, read-error from disk. |
49d0b21b | 140 | */ |
781ca602 | 141 | if (!folio_test_uptodate(folio)) { |
49d0b21b JA |
142 | err = -EIO; |
143 | goto error; | |
144 | } | |
145 | ||
781ca602 MWO |
146 | /* Folio is ok after all, we are done */ |
147 | folio_unlock(folio); | |
5274f052 JA |
148 | } |
149 | ||
f84d7519 | 150 | return 0; |
49d0b21b | 151 | error: |
781ca602 | 152 | folio_unlock(folio); |
f84d7519 | 153 | return err; |
70524490 JA |
154 | } |
155 | ||
708e3508 | 156 | const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
c928f642 CH |
157 | .confirm = page_cache_pipe_buf_confirm, |
158 | .release = page_cache_pipe_buf_release, | |
159 | .try_steal = page_cache_pipe_buf_try_steal, | |
160 | .get = generic_pipe_buf_get, | |
5274f052 JA |
161 | }; |
162 | ||
c928f642 CH |
163 | static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
164 | struct pipe_buffer *buf) | |
912d35f8 | 165 | { |
7afa6fd0 | 166 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
c928f642 | 167 | return false; |
7afa6fd0 | 168 | |
1432873a | 169 | buf->flags |= PIPE_BUF_FLAG_LRU; |
c928f642 | 170 | return generic_pipe_buf_try_steal(pipe, buf); |
912d35f8 JA |
171 | } |
172 | ||
d4c3cca9 | 173 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
c928f642 CH |
174 | .release = page_cache_pipe_buf_release, |
175 | .try_steal = user_page_pipe_buf_try_steal, | |
176 | .get = generic_pipe_buf_get, | |
912d35f8 JA |
177 | }; |
178 | ||
825cdcb1 NK |
179 | static void wakeup_pipe_readers(struct pipe_inode_info *pipe) |
180 | { | |
181 | smp_mb(); | |
0ddad21d LT |
182 | if (waitqueue_active(&pipe->rd_wait)) |
183 | wake_up_interruptible(&pipe->rd_wait); | |
825cdcb1 NK |
184 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
185 | } | |
186 | ||
932cc6d4 JA |
187 | /** |
188 | * splice_to_pipe - fill passed data into a pipe | |
189 | * @pipe: pipe to fill | |
190 | * @spd: data to fill | |
191 | * | |
192 | * Description: | |
79685b8d | 193 | * @spd contains a map of pages and len/offset tuples, along with |
932cc6d4 JA |
194 | * the struct pipe_buf_operations associated with these pages. This |
195 | * function will link that data to the pipe. | |
196 | * | |
83f9135b | 197 | */ |
d6b29d7c JA |
198 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
199 | struct splice_pipe_desc *spd) | |
5274f052 | 200 | { |
00de00bd | 201 | unsigned int spd_pages = spd->nr_pages; |
8cefc107 DH |
202 | unsigned int tail = pipe->tail; |
203 | unsigned int head = pipe->head; | |
204 | unsigned int mask = pipe->ring_size - 1; | |
8924feff | 205 | int ret = 0, page_nr = 0; |
5274f052 | 206 | |
d6785d91 RV |
207 | if (!spd_pages) |
208 | return 0; | |
209 | ||
8924feff AV |
210 | if (unlikely(!pipe->readers)) { |
211 | send_sig(SIGPIPE, current, 0); | |
212 | ret = -EPIPE; | |
213 | goto out; | |
214 | } | |
5274f052 | 215 | |
6718b6f8 | 216 | while (!pipe_full(head, tail, pipe->max_usage)) { |
8cefc107 | 217 | struct pipe_buffer *buf = &pipe->bufs[head & mask]; |
5274f052 | 218 | |
8924feff AV |
219 | buf->page = spd->pages[page_nr]; |
220 | buf->offset = spd->partial[page_nr].offset; | |
221 | buf->len = spd->partial[page_nr].len; | |
222 | buf->private = spd->partial[page_nr].private; | |
223 | buf->ops = spd->ops; | |
5a81e6a1 | 224 | buf->flags = 0; |
5274f052 | 225 | |
8cefc107 DH |
226 | head++; |
227 | pipe->head = head; | |
8924feff AV |
228 | page_nr++; |
229 | ret += buf->len; | |
29e35094 | 230 | |
8924feff | 231 | if (!--spd->nr_pages) |
5274f052 | 232 | break; |
5274f052 JA |
233 | } |
234 | ||
8924feff AV |
235 | if (!ret) |
236 | ret = -EAGAIN; | |
5274f052 | 237 | |
8924feff | 238 | out: |
00de00bd | 239 | while (page_nr < spd_pages) |
bbdfc2f7 | 240 | spd->spd_release(spd, page_nr++); |
5274f052 JA |
241 | |
242 | return ret; | |
243 | } | |
2b514574 | 244 | EXPORT_SYMBOL_GPL(splice_to_pipe); |
5274f052 | 245 | |
79fddc4e AV |
246 | ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
247 | { | |
8cefc107 DH |
248 | unsigned int head = pipe->head; |
249 | unsigned int tail = pipe->tail; | |
250 | unsigned int mask = pipe->ring_size - 1; | |
79fddc4e AV |
251 | int ret; |
252 | ||
253 | if (unlikely(!pipe->readers)) { | |
254 | send_sig(SIGPIPE, current, 0); | |
255 | ret = -EPIPE; | |
6718b6f8 | 256 | } else if (pipe_full(head, tail, pipe->max_usage)) { |
79fddc4e AV |
257 | ret = -EAGAIN; |
258 | } else { | |
8cefc107 DH |
259 | pipe->bufs[head & mask] = *buf; |
260 | pipe->head = head + 1; | |
79fddc4e AV |
261 | return buf->len; |
262 | } | |
a779638c | 263 | pipe_buf_release(pipe, buf); |
79fddc4e AV |
264 | return ret; |
265 | } | |
266 | EXPORT_SYMBOL(add_to_pipe); | |
267 | ||
35f3d14d JA |
268 | /* |
269 | * Check if we need to grow the arrays holding pages and partial page | |
270 | * descriptions. | |
271 | */ | |
047fe360 | 272 | int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) |
35f3d14d | 273 | { |
6718b6f8 | 274 | unsigned int max_usage = READ_ONCE(pipe->max_usage); |
047fe360 | 275 | |
8cefc107 DH |
276 | spd->nr_pages_max = max_usage; |
277 | if (max_usage <= PIPE_DEF_BUFFERS) | |
35f3d14d JA |
278 | return 0; |
279 | ||
8cefc107 DH |
280 | spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); |
281 | spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), | |
6da2ec56 | 282 | GFP_KERNEL); |
35f3d14d JA |
283 | |
284 | if (spd->pages && spd->partial) | |
285 | return 0; | |
286 | ||
287 | kfree(spd->pages); | |
288 | kfree(spd->partial); | |
289 | return -ENOMEM; | |
290 | } | |
291 | ||
047fe360 | 292 | void splice_shrink_spd(struct splice_pipe_desc *spd) |
35f3d14d | 293 | { |
047fe360 | 294 | if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) |
35f3d14d JA |
295 | return; |
296 | ||
297 | kfree(spd->pages); | |
298 | kfree(spd->partial); | |
299 | } | |
300 | ||
9eee8bd8 DH |
301 | /** |
302 | * copy_splice_read - Copy data from a file and splice the copy into a pipe | |
303 | * @in: The file to read from | |
304 | * @ppos: Pointer to the file position to read from | |
305 | * @pipe: The pipe to splice into | |
306 | * @len: The amount to splice | |
307 | * @flags: The SPLICE_F_* flags | |
308 | * | |
309 | * This function allocates a bunch of pages sufficient to hold the requested | |
310 | * amount of data (but limited by the remaining pipe capacity), passes it to | |
311 | * the file's ->read_iter() to read into and then splices the used pages into | |
312 | * the pipe. | |
313 | * | |
314 | * Return: On success, the number of bytes read will be returned and *@ppos | |
315 | * will be updated if appropriate; 0 will be returned if there is no more data | |
316 | * to be read; -EAGAIN will be returned if the pipe had no space, and some | |
317 | * other negative error code will be returned on error. A short read may occur | |
318 | * if the pipe has insufficient space, we reach the end of the data or we hit a | |
319 | * hole. | |
33b3b041 | 320 | */ |
69df79a4 DH |
321 | ssize_t copy_splice_read(struct file *in, loff_t *ppos, |
322 | struct pipe_inode_info *pipe, | |
323 | size_t len, unsigned int flags) | |
33b3b041 DH |
324 | { |
325 | struct iov_iter to; | |
326 | struct bio_vec *bv; | |
327 | struct kiocb kiocb; | |
328 | struct page **pages; | |
329 | ssize_t ret; | |
e69f37bc | 330 | size_t used, npages, chunk, remain, keep = 0; |
33b3b041 DH |
331 | int i; |
332 | ||
333 | /* Work out how much data we can actually add into the pipe */ | |
334 | used = pipe_occupancy(pipe->head, pipe->tail); | |
335 | npages = max_t(ssize_t, pipe->max_usage - used, 0); | |
336 | len = min_t(size_t, len, npages * PAGE_SIZE); | |
337 | npages = DIV_ROUND_UP(len, PAGE_SIZE); | |
338 | ||
339 | bv = kzalloc(array_size(npages, sizeof(bv[0])) + | |
340 | array_size(npages, sizeof(struct page *)), GFP_KERNEL); | |
341 | if (!bv) | |
342 | return -ENOMEM; | |
343 | ||
e69f37bc | 344 | pages = (struct page **)(bv + npages); |
33b3b041 DH |
345 | npages = alloc_pages_bulk_array(GFP_USER, npages, pages); |
346 | if (!npages) { | |
347 | kfree(bv); | |
348 | return -ENOMEM; | |
349 | } | |
350 | ||
351 | remain = len = min_t(size_t, len, npages * PAGE_SIZE); | |
352 | ||
353 | for (i = 0; i < npages; i++) { | |
354 | chunk = min_t(size_t, PAGE_SIZE, remain); | |
355 | bv[i].bv_page = pages[i]; | |
356 | bv[i].bv_offset = 0; | |
357 | bv[i].bv_len = chunk; | |
358 | remain -= chunk; | |
359 | } | |
360 | ||
361 | /* Do the I/O */ | |
362 | iov_iter_bvec(&to, ITER_DEST, bv, npages, len); | |
363 | init_sync_kiocb(&kiocb, in); | |
364 | kiocb.ki_pos = *ppos; | |
365 | ret = call_read_iter(in, &kiocb, &to); | |
366 | ||
33b3b041 | 367 | if (ret > 0) { |
e69f37bc | 368 | keep = DIV_ROUND_UP(ret, PAGE_SIZE); |
33b3b041 | 369 | *ppos = kiocb.ki_pos; |
33b3b041 DH |
370 | } |
371 | ||
2e82f6c3 CH |
372 | /* |
373 | * Callers of ->splice_read() expect -EAGAIN on "can't put anything in | |
374 | * there", rather than -EFAULT. | |
375 | */ | |
376 | if (ret == -EFAULT) | |
377 | ret = -EAGAIN; | |
378 | ||
33b3b041 | 379 | /* Free any pages that didn't get touched at all. */ |
e69f37bc DH |
380 | if (keep < npages) |
381 | release_pages(pages + keep, npages - keep); | |
33b3b041 DH |
382 | |
383 | /* Push the remaining pages into the pipe. */ | |
e69f37bc DH |
384 | remain = ret; |
385 | for (i = 0; i < keep; i++) { | |
33b3b041 DH |
386 | struct pipe_buffer *buf = pipe_head_buf(pipe); |
387 | ||
388 | chunk = min_t(size_t, remain, PAGE_SIZE); | |
389 | *buf = (struct pipe_buffer) { | |
390 | .ops = &default_pipe_buf_ops, | |
391 | .page = bv[i].bv_page, | |
392 | .offset = 0, | |
393 | .len = chunk, | |
394 | }; | |
395 | pipe->head++; | |
396 | remain -= chunk; | |
397 | } | |
398 | ||
399 | kfree(bv); | |
400 | return ret; | |
401 | } | |
69df79a4 | 402 | EXPORT_SYMBOL(copy_splice_read); |
33b3b041 | 403 | |
241699cd | 404 | const struct pipe_buf_operations default_pipe_buf_ops = { |
c928f642 CH |
405 | .release = generic_pipe_buf_release, |
406 | .try_steal = generic_pipe_buf_try_steal, | |
407 | .get = generic_pipe_buf_get, | |
6818173b MS |
408 | }; |
409 | ||
28a625cb MS |
410 | /* Pipe buffer operations for a socket and similar. */ |
411 | const struct pipe_buf_operations nosteal_pipe_buf_ops = { | |
c928f642 CH |
412 | .release = generic_pipe_buf_release, |
413 | .get = generic_pipe_buf_get, | |
28a625cb MS |
414 | }; |
415 | EXPORT_SYMBOL(nosteal_pipe_buf_ops); | |
416 | ||
b3c2d2dd MS |
417 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
418 | { | |
419 | smp_mb(); | |
0ddad21d LT |
420 | if (waitqueue_active(&pipe->wr_wait)) |
421 | wake_up_interruptible(&pipe->wr_wait); | |
b3c2d2dd MS |
422 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
423 | } | |
424 | ||
932cc6d4 | 425 | /** |
b3c2d2dd | 426 | * splice_from_pipe_feed - feed available data from a pipe to a file |
932cc6d4 JA |
427 | * @pipe: pipe to splice from |
428 | * @sd: information to @actor | |
429 | * @actor: handler that splices the data | |
430 | * | |
431 | * Description: | |
b3c2d2dd MS |
432 | * This function loops over the pipe and calls @actor to do the |
433 | * actual moving of a single struct pipe_buffer to the desired | |
434 | * destination. It returns when there's no more buffers left in | |
435 | * the pipe or if the requested number of bytes (@sd->total_len) | |
436 | * have been copied. It returns a positive number (one) if the | |
437 | * pipe needs to be filled with more data, zero if the required | |
438 | * number of bytes have been copied and -errno on error. | |
932cc6d4 | 439 | * |
b3c2d2dd MS |
440 | * This, together with splice_from_pipe_{begin,end,next}, may be |
441 | * used to implement the functionality of __splice_from_pipe() when | |
442 | * locking is required around copying the pipe buffers to the | |
443 | * destination. | |
83f9135b | 444 | */ |
96f9bc8f | 445 | static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
b3c2d2dd | 446 | splice_actor *actor) |
5274f052 | 447 | { |
8cefc107 DH |
448 | unsigned int head = pipe->head; |
449 | unsigned int tail = pipe->tail; | |
450 | unsigned int mask = pipe->ring_size - 1; | |
b3c2d2dd | 451 | int ret; |
5274f052 | 452 | |
ec057595 | 453 | while (!pipe_empty(head, tail)) { |
8cefc107 | 454 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
5274f052 | 455 | |
b3c2d2dd MS |
456 | sd->len = buf->len; |
457 | if (sd->len > sd->total_len) | |
458 | sd->len = sd->total_len; | |
5274f052 | 459 | |
fba597db | 460 | ret = pipe_buf_confirm(pipe, buf); |
a8adbe37 | 461 | if (unlikely(ret)) { |
b3c2d2dd MS |
462 | if (ret == -ENODATA) |
463 | ret = 0; | |
464 | return ret; | |
465 | } | |
a8adbe37 MM |
466 | |
467 | ret = actor(pipe, buf, sd); | |
468 | if (ret <= 0) | |
469 | return ret; | |
470 | ||
b3c2d2dd MS |
471 | buf->offset += ret; |
472 | buf->len -= ret; | |
473 | ||
474 | sd->num_spliced += ret; | |
475 | sd->len -= ret; | |
476 | sd->pos += ret; | |
477 | sd->total_len -= ret; | |
478 | ||
479 | if (!buf->len) { | |
a779638c | 480 | pipe_buf_release(pipe, buf); |
8cefc107 DH |
481 | tail++; |
482 | pipe->tail = tail; | |
6447a3cf | 483 | if (pipe->files) |
b3c2d2dd MS |
484 | sd->need_wakeup = true; |
485 | } | |
5274f052 | 486 | |
b3c2d2dd MS |
487 | if (!sd->total_len) |
488 | return 0; | |
489 | } | |
5274f052 | 490 | |
b3c2d2dd MS |
491 | return 1; |
492 | } | |
5274f052 | 493 | |
d1a819a2 LT |
494 | /* We know we have a pipe buffer, but maybe it's empty? */ |
495 | static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) | |
496 | { | |
497 | unsigned int tail = pipe->tail; | |
498 | unsigned int mask = pipe->ring_size - 1; | |
499 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
500 | ||
501 | if (unlikely(!buf->len)) { | |
502 | pipe_buf_release(pipe, buf); | |
503 | pipe->tail = tail+1; | |
504 | return true; | |
505 | } | |
506 | ||
507 | return false; | |
508 | } | |
509 | ||
b3c2d2dd MS |
510 | /** |
511 | * splice_from_pipe_next - wait for some data to splice from | |
512 | * @pipe: pipe to splice from | |
513 | * @sd: information about the splice operation | |
514 | * | |
515 | * Description: | |
516 | * This function will wait for some data and return a positive | |
517 | * value (one) if pipe buffers are available. It will return zero | |
518 | * or -errno if no more data needs to be spliced. | |
519 | */ | |
96f9bc8f | 520 | static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
b3c2d2dd | 521 | { |
c725bfce JK |
522 | /* |
523 | * Check for signal early to make process killable when there are | |
524 | * always buffers available | |
525 | */ | |
526 | if (signal_pending(current)) | |
527 | return -ERESTARTSYS; | |
528 | ||
d1a819a2 | 529 | repeat: |
8cefc107 | 530 | while (pipe_empty(pipe->head, pipe->tail)) { |
b3c2d2dd MS |
531 | if (!pipe->writers) |
532 | return 0; | |
016b661e | 533 | |
a28c8b9d | 534 | if (sd->num_spliced) |
b3c2d2dd | 535 | return 0; |
73d62d83 | 536 | |
b3c2d2dd MS |
537 | if (sd->flags & SPLICE_F_NONBLOCK) |
538 | return -EAGAIN; | |
5274f052 | 539 | |
b3c2d2dd MS |
540 | if (signal_pending(current)) |
541 | return -ERESTARTSYS; | |
5274f052 | 542 | |
b3c2d2dd MS |
543 | if (sd->need_wakeup) { |
544 | wakeup_pipe_writers(pipe); | |
545 | sd->need_wakeup = false; | |
5274f052 JA |
546 | } |
547 | ||
472e5b05 | 548 | pipe_wait_readable(pipe); |
b3c2d2dd | 549 | } |
29e35094 | 550 | |
d1a819a2 LT |
551 | if (eat_empty_buffer(pipe)) |
552 | goto repeat; | |
553 | ||
b3c2d2dd MS |
554 | return 1; |
555 | } | |
5274f052 | 556 | |
b3c2d2dd MS |
557 | /** |
558 | * splice_from_pipe_begin - start splicing from pipe | |
b80901bb | 559 | * @sd: information about the splice operation |
b3c2d2dd MS |
560 | * |
561 | * Description: | |
562 | * This function should be called before a loop containing | |
563 | * splice_from_pipe_next() and splice_from_pipe_feed() to | |
564 | * initialize the necessary fields of @sd. | |
565 | */ | |
96f9bc8f | 566 | static void splice_from_pipe_begin(struct splice_desc *sd) |
b3c2d2dd MS |
567 | { |
568 | sd->num_spliced = 0; | |
569 | sd->need_wakeup = false; | |
570 | } | |
5274f052 | 571 | |
b3c2d2dd MS |
572 | /** |
573 | * splice_from_pipe_end - finish splicing from pipe | |
574 | * @pipe: pipe to splice from | |
575 | * @sd: information about the splice operation | |
576 | * | |
577 | * Description: | |
578 | * This function will wake up pipe writers if necessary. It should | |
579 | * be called after a loop containing splice_from_pipe_next() and | |
580 | * splice_from_pipe_feed(). | |
581 | */ | |
96f9bc8f | 582 | static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
b3c2d2dd MS |
583 | { |
584 | if (sd->need_wakeup) | |
585 | wakeup_pipe_writers(pipe); | |
586 | } | |
5274f052 | 587 | |
b3c2d2dd MS |
588 | /** |
589 | * __splice_from_pipe - splice data from a pipe to given actor | |
590 | * @pipe: pipe to splice from | |
591 | * @sd: information to @actor | |
592 | * @actor: handler that splices the data | |
593 | * | |
594 | * Description: | |
595 | * This function does little more than loop over the pipe and call | |
596 | * @actor to do the actual moving of a single struct pipe_buffer to | |
2dc334f1 | 597 | * the desired destination. See pipe_to_file, pipe_to_sendmsg, or |
b3c2d2dd MS |
598 | * pipe_to_user. |
599 | * | |
600 | */ | |
601 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, | |
602 | splice_actor *actor) | |
603 | { | |
604 | int ret; | |
5274f052 | 605 | |
b3c2d2dd MS |
606 | splice_from_pipe_begin(sd); |
607 | do { | |
c2489e07 | 608 | cond_resched(); |
b3c2d2dd MS |
609 | ret = splice_from_pipe_next(pipe, sd); |
610 | if (ret > 0) | |
611 | ret = splice_from_pipe_feed(pipe, sd, actor); | |
612 | } while (ret > 0); | |
613 | splice_from_pipe_end(pipe, sd); | |
614 | ||
615 | return sd->num_spliced ? sd->num_spliced : ret; | |
5274f052 | 616 | } |
40bee44e | 617 | EXPORT_SYMBOL(__splice_from_pipe); |
5274f052 | 618 | |
932cc6d4 JA |
619 | /** |
620 | * splice_from_pipe - splice data from a pipe to a file | |
621 | * @pipe: pipe to splice from | |
622 | * @out: file to splice to | |
623 | * @ppos: position in @out | |
624 | * @len: how many bytes to splice | |
625 | * @flags: splice modifier flags | |
626 | * @actor: handler that splices the data | |
627 | * | |
628 | * Description: | |
2933970b | 629 | * See __splice_from_pipe. This function locks the pipe inode, |
932cc6d4 JA |
630 | * otherwise it's identical to __splice_from_pipe(). |
631 | * | |
632 | */ | |
6da61809 MF |
633 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
634 | loff_t *ppos, size_t len, unsigned int flags, | |
635 | splice_actor *actor) | |
636 | { | |
637 | ssize_t ret; | |
c66ab6fa JA |
638 | struct splice_desc sd = { |
639 | .total_len = len, | |
640 | .flags = flags, | |
641 | .pos = *ppos, | |
6a14b90b | 642 | .u.file = out, |
c66ab6fa | 643 | }; |
6da61809 | 644 | |
61e0d47c | 645 | pipe_lock(pipe); |
c66ab6fa | 646 | ret = __splice_from_pipe(pipe, &sd, actor); |
61e0d47c | 647 | pipe_unlock(pipe); |
6da61809 MF |
648 | |
649 | return ret; | |
650 | } | |
651 | ||
8d020765 AV |
652 | /** |
653 | * iter_file_splice_write - splice data from a pipe to a file | |
654 | * @pipe: pipe info | |
655 | * @out: file to write to | |
656 | * @ppos: position in @out | |
657 | * @len: number of bytes to splice | |
658 | * @flags: splice modifier flags | |
659 | * | |
660 | * Description: | |
661 | * Will either move or copy pages (determined by @flags options) from | |
662 | * the given pipe inode to the given file. | |
663 | * This one is ->write_iter-based. | |
664 | * | |
665 | */ | |
666 | ssize_t | |
667 | iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, | |
668 | loff_t *ppos, size_t len, unsigned int flags) | |
669 | { | |
670 | struct splice_desc sd = { | |
671 | .total_len = len, | |
672 | .flags = flags, | |
673 | .pos = *ppos, | |
674 | .u.file = out, | |
675 | }; | |
6718b6f8 | 676 | int nbufs = pipe->max_usage; |
8d020765 AV |
677 | struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), |
678 | GFP_KERNEL); | |
679 | ssize_t ret; | |
680 | ||
681 | if (unlikely(!array)) | |
682 | return -ENOMEM; | |
683 | ||
684 | pipe_lock(pipe); | |
685 | ||
686 | splice_from_pipe_begin(&sd); | |
687 | while (sd.total_len) { | |
688 | struct iov_iter from; | |
ec057595 | 689 | unsigned int head, tail, mask; |
8d020765 | 690 | size_t left; |
8cefc107 | 691 | int n; |
8d020765 AV |
692 | |
693 | ret = splice_from_pipe_next(pipe, &sd); | |
694 | if (ret <= 0) | |
695 | break; | |
696 | ||
6718b6f8 | 697 | if (unlikely(nbufs < pipe->max_usage)) { |
8d020765 | 698 | kfree(array); |
6718b6f8 | 699 | nbufs = pipe->max_usage; |
8d020765 AV |
700 | array = kcalloc(nbufs, sizeof(struct bio_vec), |
701 | GFP_KERNEL); | |
702 | if (!array) { | |
703 | ret = -ENOMEM; | |
704 | break; | |
705 | } | |
706 | } | |
707 | ||
ec057595 LT |
708 | head = pipe->head; |
709 | tail = pipe->tail; | |
710 | mask = pipe->ring_size - 1; | |
711 | ||
8d020765 AV |
712 | /* build the vector */ |
713 | left = sd.total_len; | |
0f1d344f | 714 | for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { |
8cefc107 | 715 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
8d020765 AV |
716 | size_t this_len = buf->len; |
717 | ||
0f1d344f PB |
718 | /* zero-length bvecs are not supported, skip them */ |
719 | if (!this_len) | |
720 | continue; | |
721 | this_len = min(this_len, left); | |
8d020765 | 722 | |
fba597db | 723 | ret = pipe_buf_confirm(pipe, buf); |
8d020765 AV |
724 | if (unlikely(ret)) { |
725 | if (ret == -ENODATA) | |
726 | ret = 0; | |
727 | goto done; | |
728 | } | |
729 | ||
664e4078 CH |
730 | bvec_set_page(&array[n], buf->page, this_len, |
731 | buf->offset); | |
8d020765 | 732 | left -= this_len; |
0f1d344f | 733 | n++; |
8d020765 AV |
734 | } |
735 | ||
de4eda9d | 736 | iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); |
abbb6589 | 737 | ret = vfs_iter_write(out, &from, &sd.pos, 0); |
8d020765 AV |
738 | if (ret <= 0) |
739 | break; | |
740 | ||
741 | sd.num_spliced += ret; | |
742 | sd.total_len -= ret; | |
dbe4e192 | 743 | *ppos = sd.pos; |
8d020765 AV |
744 | |
745 | /* dismiss the fully eaten buffers, adjust the partial one */ | |
8cefc107 | 746 | tail = pipe->tail; |
8d020765 | 747 | while (ret) { |
8cefc107 | 748 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
8d020765 | 749 | if (ret >= buf->len) { |
8d020765 AV |
750 | ret -= buf->len; |
751 | buf->len = 0; | |
a779638c | 752 | pipe_buf_release(pipe, buf); |
8cefc107 DH |
753 | tail++; |
754 | pipe->tail = tail; | |
8d020765 AV |
755 | if (pipe->files) |
756 | sd.need_wakeup = true; | |
757 | } else { | |
758 | buf->offset += ret; | |
759 | buf->len -= ret; | |
760 | ret = 0; | |
761 | } | |
762 | } | |
763 | } | |
764 | done: | |
765 | kfree(array); | |
766 | splice_from_pipe_end(pipe, &sd); | |
767 | ||
768 | pipe_unlock(pipe); | |
769 | ||
770 | if (sd.num_spliced) | |
771 | ret = sd.num_spliced; | |
772 | ||
773 | return ret; | |
774 | } | |
775 | ||
776 | EXPORT_SYMBOL(iter_file_splice_write); | |
777 | ||
2dc334f1 | 778 | #ifdef CONFIG_NET |
83f9135b | 779 | /** |
2dc334f1 | 780 | * splice_to_socket - splice data from a pipe to a socket |
932cc6d4 | 781 | * @pipe: pipe to splice from |
83f9135b | 782 | * @out: socket to write to |
932cc6d4 | 783 | * @ppos: position in @out |
83f9135b JA |
784 | * @len: number of bytes to splice |
785 | * @flags: splice modifier flags | |
786 | * | |
932cc6d4 JA |
787 | * Description: |
788 | * Will send @len bytes from the pipe to a network socket. No data copying | |
789 | * is involved. | |
83f9135b JA |
790 | * |
791 | */ | |
2dc334f1 DH |
792 | ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, |
793 | loff_t *ppos, size_t len, unsigned int flags) | |
5274f052 | 794 | { |
2dc334f1 DH |
795 | struct socket *sock = sock_from_file(out); |
796 | struct bio_vec bvec[16]; | |
797 | struct msghdr msg = {}; | |
798 | ssize_t ret = 0; | |
799 | size_t spliced = 0; | |
800 | bool need_wakeup = false; | |
801 | ||
802 | pipe_lock(pipe); | |
803 | ||
804 | while (len > 0) { | |
805 | unsigned int head, tail, mask, bc = 0; | |
806 | size_t remain = len; | |
807 | ||
808 | /* | |
809 | * Check for signal early to make process killable when there | |
810 | * are always buffers available | |
811 | */ | |
812 | ret = -ERESTARTSYS; | |
813 | if (signal_pending(current)) | |
814 | break; | |
815 | ||
816 | while (pipe_empty(pipe->head, pipe->tail)) { | |
817 | ret = 0; | |
818 | if (!pipe->writers) | |
819 | goto out; | |
820 | ||
821 | if (spliced) | |
822 | goto out; | |
823 | ||
824 | ret = -EAGAIN; | |
825 | if (flags & SPLICE_F_NONBLOCK) | |
826 | goto out; | |
827 | ||
828 | ret = -ERESTARTSYS; | |
829 | if (signal_pending(current)) | |
830 | goto out; | |
831 | ||
832 | if (need_wakeup) { | |
833 | wakeup_pipe_writers(pipe); | |
834 | need_wakeup = false; | |
835 | } | |
836 | ||
837 | pipe_wait_readable(pipe); | |
838 | } | |
839 | ||
840 | head = pipe->head; | |
841 | tail = pipe->tail; | |
842 | mask = pipe->ring_size - 1; | |
843 | ||
844 | while (!pipe_empty(head, tail)) { | |
845 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
846 | size_t seg; | |
847 | ||
848 | if (!buf->len) { | |
849 | tail++; | |
850 | continue; | |
851 | } | |
5274f052 | 852 | |
2dc334f1 | 853 | seg = min_t(size_t, remain, buf->len); |
2dc334f1 DH |
854 | |
855 | ret = pipe_buf_confirm(pipe, buf); | |
856 | if (unlikely(ret)) { | |
857 | if (ret == -ENODATA) | |
858 | ret = 0; | |
859 | break; | |
860 | } | |
5274f052 | 861 | |
2dc334f1 DH |
862 | bvec_set_page(&bvec[bc++], buf->page, seg, buf->offset); |
863 | remain -= seg; | |
ca2d49f7 | 864 | if (remain == 0 || bc >= ARRAY_SIZE(bvec)) |
2dc334f1 | 865 | break; |
ca2d49f7 | 866 | tail++; |
2dc334f1 DH |
867 | } |
868 | ||
869 | if (!bc) | |
870 | break; | |
871 | ||
872 | msg.msg_flags = MSG_SPLICE_PAGES; | |
873 | if (flags & SPLICE_F_MORE) | |
874 | msg.msg_flags |= MSG_MORE; | |
875 | if (remain && pipe_occupancy(pipe->head, tail) > 0) | |
876 | msg.msg_flags |= MSG_MORE; | |
0f0fa27b JS |
877 | if (out->f_flags & O_NONBLOCK) |
878 | msg.msg_flags |= MSG_DONTWAIT; | |
2dc334f1 DH |
879 | |
880 | iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, bvec, bc, | |
881 | len - remain); | |
882 | ret = sock_sendmsg(sock, &msg); | |
883 | if (ret <= 0) | |
884 | break; | |
885 | ||
886 | spliced += ret; | |
887 | len -= ret; | |
888 | tail = pipe->tail; | |
889 | while (ret > 0) { | |
890 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; | |
891 | size_t seg = min_t(size_t, ret, buf->len); | |
892 | ||
893 | buf->offset += seg; | |
894 | buf->len -= seg; | |
895 | ret -= seg; | |
896 | ||
897 | if (!buf->len) { | |
898 | pipe_buf_release(pipe, buf); | |
899 | tail++; | |
900 | } | |
901 | } | |
902 | ||
903 | if (tail != pipe->tail) { | |
904 | pipe->tail = tail; | |
905 | if (pipe->files) | |
906 | need_wakeup = true; | |
907 | } | |
908 | } | |
909 | ||
910 | out: | |
911 | pipe_unlock(pipe); | |
912 | if (need_wakeup) | |
913 | wakeup_pipe_writers(pipe); | |
914 | return spliced ?: ret; | |
915 | } | |
916 | #endif | |
a0f06780 | 917 | |
36e2c742 CH |
918 | static int warn_unsupported(struct file *file, const char *op) |
919 | { | |
920 | pr_debug_ratelimited( | |
921 | "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", | |
922 | op, file, current->pid, current->comm); | |
923 | return -EINVAL; | |
924 | } | |
925 | ||
83f9135b JA |
926 | /* |
927 | * Attempt to initiate a splice from pipe to file. | |
928 | */ | |
3a326a2c | 929 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
cbb7e577 | 930 | loff_t *ppos, size_t len, unsigned int flags) |
5274f052 | 931 | { |
36e2c742 CH |
932 | if (unlikely(!out->f_op->splice_write)) |
933 | return warn_unsupported(out, "write"); | |
934 | return out->f_op->splice_write(pipe, out, ppos, len, flags); | |
5274f052 JA |
935 | } |
936 | ||
2bfc6685 DH |
937 | /* |
938 | * Indicate to the caller that there was a premature EOF when reading from the | |
939 | * source and the caller didn't indicate they would be sending more data after | |
940 | * this. | |
941 | */ | |
942 | static void do_splice_eof(struct splice_desc *sd) | |
943 | { | |
944 | if (sd->splice_eof) | |
945 | sd->splice_eof(sd); | |
946 | } | |
947 | ||
6a3f30b8 DH |
948 | /** |
949 | * vfs_splice_read - Read data from a file and splice it into a pipe | |
950 | * @in: File to splice from | |
951 | * @ppos: Input file offset | |
952 | * @pipe: Pipe to splice to | |
953 | * @len: Number of bytes to splice | |
954 | * @flags: Splice modifier flags (SPLICE_F_*) | |
955 | * | |
956 | * Splice the requested amount of data from the input file to the pipe. This | |
957 | * is synchronous as the caller must hold the pipe lock across the entire | |
958 | * operation. | |
959 | * | |
960 | * If successful, it returns the amount of data spliced, 0 if it hit the EOF or | |
961 | * a hole and a negative error code otherwise. | |
83f9135b | 962 | */ |
6a3f30b8 DH |
963 | long vfs_splice_read(struct file *in, loff_t *ppos, |
964 | struct pipe_inode_info *pipe, size_t len, | |
965 | unsigned int flags) | |
5274f052 | 966 | { |
313d64a3 | 967 | unsigned int p_space; |
5274f052 JA |
968 | int ret; |
969 | ||
49570e9b | 970 | if (unlikely(!(in->f_mode & FMODE_READ))) |
5274f052 | 971 | return -EBADF; |
123856f0 DH |
972 | if (!len) |
973 | return 0; | |
5274f052 | 974 | |
313d64a3 AV |
975 | /* Don't try to read more the pipe has space for. */ |
976 | p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); | |
977 | len = min_t(size_t, len, p_space << PAGE_SHIFT); | |
978 | ||
cbb7e577 | 979 | ret = rw_verify_area(READ, in, ppos, len); |
5274f052 JA |
980 | if (unlikely(ret < 0)) |
981 | return ret; | |
982 | ||
03cc0789 AV |
983 | if (unlikely(len > MAX_RW_COUNT)) |
984 | len = MAX_RW_COUNT; | |
985 | ||
36e2c742 CH |
986 | if (unlikely(!in->f_op->splice_read)) |
987 | return warn_unsupported(in, "read"); | |
aa3dbde8 | 988 | /* |
b85930a0 DH |
989 | * O_DIRECT and DAX don't deal with the pagecache, so we allocate a |
990 | * buffer, copy into it and splice that into the pipe. | |
aa3dbde8 | 991 | */ |
b85930a0 | 992 | if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host)) |
aa3dbde8 | 993 | return copy_splice_read(in, ppos, pipe, len, flags); |
36e2c742 | 994 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
5274f052 | 995 | } |
6a3f30b8 | 996 | EXPORT_SYMBOL_GPL(vfs_splice_read); |
5274f052 | 997 | |
932cc6d4 JA |
998 | /** |
999 | * splice_direct_to_actor - splices data directly between two non-pipes | |
1000 | * @in: file to splice from | |
1001 | * @sd: actor information on where to splice to | |
1002 | * @actor: handles the data splicing | |
1003 | * | |
1004 | * Description: | |
1005 | * This is a special case helper to splice directly between two | |
1006 | * points, without requiring an explicit pipe. Internally an allocated | |
79685b8d | 1007 | * pipe is cached in the process, and reused during the lifetime of |
932cc6d4 JA |
1008 | * that process. |
1009 | * | |
c66ab6fa JA |
1010 | */ |
1011 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, | |
1012 | splice_direct_actor *actor) | |
b92ce558 JA |
1013 | { |
1014 | struct pipe_inode_info *pipe; | |
1015 | long ret, bytes; | |
c66ab6fa | 1016 | size_t len; |
0ff28d9f | 1017 | int i, flags, more; |
b92ce558 JA |
1018 | |
1019 | /* | |
97ef77c5 JD |
1020 | * We require the input to be seekable, as we don't want to randomly |
1021 | * drop data for eg socket -> socket splicing. Use the piped splicing | |
1022 | * for that! | |
b92ce558 | 1023 | */ |
97ef77c5 | 1024 | if (unlikely(!(in->f_mode & FMODE_LSEEK))) |
b92ce558 JA |
1025 | return -EINVAL; |
1026 | ||
1027 | /* | |
1028 | * neither in nor out is a pipe, setup an internal pipe attached to | |
1029 | * 'out' and transfer the wanted data from 'in' to 'out' through that | |
1030 | */ | |
1031 | pipe = current->splice_pipe; | |
49570e9b | 1032 | if (unlikely(!pipe)) { |
7bee130e | 1033 | pipe = alloc_pipe_info(); |
b92ce558 JA |
1034 | if (!pipe) |
1035 | return -ENOMEM; | |
1036 | ||
1037 | /* | |
1038 | * We don't have an immediate reader, but we'll read the stuff | |
00522fb4 | 1039 | * out of the pipe right after the splice_to_pipe(). So set |
b92ce558 JA |
1040 | * PIPE_READERS appropriately. |
1041 | */ | |
1042 | pipe->readers = 1; | |
1043 | ||
1044 | current->splice_pipe = pipe; | |
1045 | } | |
1046 | ||
1047 | /* | |
73d62d83 | 1048 | * Do the splice. |
b92ce558 | 1049 | */ |
b92ce558 | 1050 | bytes = 0; |
c66ab6fa | 1051 | len = sd->total_len; |
219d9205 DH |
1052 | |
1053 | /* Don't block on output, we have to drain the direct pipe. */ | |
c66ab6fa | 1054 | flags = sd->flags; |
219d9205 | 1055 | sd->flags &= ~SPLICE_F_NONBLOCK; |
c66ab6fa JA |
1056 | |
1057 | /* | |
219d9205 DH |
1058 | * We signal MORE until we've read sufficient data to fulfill the |
1059 | * request and we keep signalling it if the caller set it. | |
c66ab6fa | 1060 | */ |
0ff28d9f | 1061 | more = sd->flags & SPLICE_F_MORE; |
219d9205 | 1062 | sd->flags |= SPLICE_F_MORE; |
b92ce558 | 1063 | |
8cefc107 | 1064 | WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); |
17614445 | 1065 | |
b92ce558 | 1066 | while (len) { |
51a92c0f | 1067 | size_t read_len; |
a82c53a0 | 1068 | loff_t pos = sd->pos, prev_pos = pos; |
b92ce558 | 1069 | |
6a3f30b8 | 1070 | ret = vfs_splice_read(in, &pos, pipe, len, flags); |
51a92c0f | 1071 | if (unlikely(ret <= 0)) |
2bfc6685 | 1072 | goto read_failure; |
b92ce558 JA |
1073 | |
1074 | read_len = ret; | |
c66ab6fa | 1075 | sd->total_len = read_len; |
b92ce558 | 1076 | |
0ff28d9f | 1077 | /* |
219d9205 DH |
1078 | * If we now have sufficient data to fulfill the request then |
1079 | * we clear SPLICE_F_MORE if it was not set initially. | |
0ff28d9f | 1080 | */ |
219d9205 | 1081 | if (read_len >= len && !more) |
0ff28d9f | 1082 | sd->flags &= ~SPLICE_F_MORE; |
219d9205 | 1083 | |
b92ce558 JA |
1084 | /* |
1085 | * NOTE: nonblocking mode only applies to the input. We | |
1086 | * must not do the output in nonblocking mode as then we | |
1087 | * could get stuck data in the internal pipe: | |
1088 | */ | |
c66ab6fa | 1089 | ret = actor(pipe, sd); |
a82c53a0 TZ |
1090 | if (unlikely(ret <= 0)) { |
1091 | sd->pos = prev_pos; | |
b92ce558 | 1092 | goto out_release; |
a82c53a0 | 1093 | } |
b92ce558 JA |
1094 | |
1095 | bytes += ret; | |
1096 | len -= ret; | |
bcd4f3ac | 1097 | sd->pos = pos; |
b92ce558 | 1098 | |
a82c53a0 TZ |
1099 | if (ret < read_len) { |
1100 | sd->pos = prev_pos + ret; | |
51a92c0f | 1101 | goto out_release; |
a82c53a0 | 1102 | } |
b92ce558 JA |
1103 | } |
1104 | ||
9e97198d | 1105 | done: |
8cefc107 | 1106 | pipe->tail = pipe->head = 0; |
80848708 | 1107 | file_accessed(in); |
b92ce558 JA |
1108 | return bytes; |
1109 | ||
2bfc6685 DH |
1110 | read_failure: |
1111 | /* | |
1112 | * If the user did *not* set SPLICE_F_MORE *and* we didn't hit that | |
1113 | * "use all of len" case that cleared SPLICE_F_MORE, *and* we did a | |
1114 | * "->splice_in()" that returned EOF (ie zero) *and* we have sent at | |
1115 | * least 1 byte *then* we will also do the ->splice_eof() call. | |
1116 | */ | |
1117 | if (ret == 0 && !more && len > 0 && bytes) | |
1118 | do_splice_eof(sd); | |
b92ce558 JA |
1119 | out_release: |
1120 | /* | |
1121 | * If we did an incomplete transfer we must release | |
1122 | * the pipe buffers in question: | |
1123 | */ | |
8cefc107 DH |
1124 | for (i = 0; i < pipe->ring_size; i++) { |
1125 | struct pipe_buffer *buf = &pipe->bufs[i]; | |
b92ce558 | 1126 | |
a779638c MS |
1127 | if (buf->ops) |
1128 | pipe_buf_release(pipe, buf); | |
b92ce558 | 1129 | } |
b92ce558 | 1130 | |
9e97198d JA |
1131 | if (!bytes) |
1132 | bytes = ret; | |
c66ab6fa | 1133 | |
9e97198d | 1134 | goto done; |
c66ab6fa JA |
1135 | } |
1136 | EXPORT_SYMBOL(splice_direct_to_actor); | |
1137 | ||
1138 | static int direct_splice_actor(struct pipe_inode_info *pipe, | |
1139 | struct splice_desc *sd) | |
1140 | { | |
6a14b90b | 1141 | struct file *file = sd->u.file; |
c66ab6fa | 1142 | |
7995bd28 | 1143 | return do_splice_from(pipe, file, sd->opos, sd->total_len, |
2cb4b05e | 1144 | sd->flags); |
c66ab6fa JA |
1145 | } |
1146 | ||
2bfc6685 DH |
1147 | static void direct_file_splice_eof(struct splice_desc *sd) |
1148 | { | |
1149 | struct file *file = sd->u.file; | |
1150 | ||
1151 | if (file->f_op->splice_eof) | |
1152 | file->f_op->splice_eof(file); | |
1153 | } | |
1154 | ||
932cc6d4 JA |
1155 | /** |
1156 | * do_splice_direct - splices data directly between two files | |
1157 | * @in: file to splice from | |
1158 | * @ppos: input file offset | |
1159 | * @out: file to splice to | |
acdb37c3 | 1160 | * @opos: output file offset |
932cc6d4 JA |
1161 | * @len: number of bytes to splice |
1162 | * @flags: splice modifier flags | |
1163 | * | |
1164 | * Description: | |
1165 | * For use by do_sendfile(). splice can easily emulate sendfile, but | |
1166 | * doing it in the application would incur an extra system call | |
1167 | * (splice in + splice out, as compared to just sendfile()). So this helper | |
1168 | * can splice directly through a process-private pipe. | |
1169 | * | |
1170 | */ | |
c66ab6fa | 1171 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
7995bd28 | 1172 | loff_t *opos, size_t len, unsigned int flags) |
c66ab6fa JA |
1173 | { |
1174 | struct splice_desc sd = { | |
1175 | .len = len, | |
1176 | .total_len = len, | |
1177 | .flags = flags, | |
1178 | .pos = *ppos, | |
6a14b90b | 1179 | .u.file = out, |
2bfc6685 | 1180 | .splice_eof = direct_file_splice_eof, |
7995bd28 | 1181 | .opos = opos, |
c66ab6fa | 1182 | }; |
51a92c0f | 1183 | long ret; |
c66ab6fa | 1184 | |
18c67cb9 AV |
1185 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
1186 | return -EBADF; | |
1187 | ||
1188 | if (unlikely(out->f_flags & O_APPEND)) | |
1189 | return -EINVAL; | |
1190 | ||
1191 | ret = rw_verify_area(WRITE, out, opos, len); | |
1192 | if (unlikely(ret < 0)) | |
1193 | return ret; | |
1194 | ||
c66ab6fa | 1195 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
51a92c0f | 1196 | if (ret > 0) |
a82c53a0 | 1197 | *ppos = sd.pos; |
51a92c0f | 1198 | |
c66ab6fa | 1199 | return ret; |
b92ce558 | 1200 | } |
1c118596 | 1201 | EXPORT_SYMBOL(do_splice_direct); |
b92ce558 | 1202 | |
8924feff AV |
1203 | static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) |
1204 | { | |
52bce911 LT |
1205 | for (;;) { |
1206 | if (unlikely(!pipe->readers)) { | |
1207 | send_sig(SIGPIPE, current, 0); | |
1208 | return -EPIPE; | |
1209 | } | |
6718b6f8 | 1210 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
52bce911 | 1211 | return 0; |
8924feff AV |
1212 | if (flags & SPLICE_F_NONBLOCK) |
1213 | return -EAGAIN; | |
1214 | if (signal_pending(current)) | |
1215 | return -ERESTARTSYS; | |
472e5b05 | 1216 | pipe_wait_writable(pipe); |
8924feff | 1217 | } |
8924feff AV |
1218 | } |
1219 | ||
7c77f0b3 MS |
1220 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
1221 | struct pipe_inode_info *opipe, | |
1222 | size_t len, unsigned int flags); | |
ddac0d39 | 1223 | |
b964bf53 | 1224 | long splice_file_to_pipe(struct file *in, |
faa97c48 AV |
1225 | struct pipe_inode_info *opipe, |
1226 | loff_t *offset, | |
1227 | size_t len, unsigned int flags) | |
1228 | { | |
1229 | long ret; | |
1230 | ||
1231 | pipe_lock(opipe); | |
1232 | ret = wait_for_space(opipe, flags); | |
1233 | if (!ret) | |
6a3f30b8 | 1234 | ret = vfs_splice_read(in, offset, opipe, len, flags); |
faa97c48 AV |
1235 | pipe_unlock(opipe); |
1236 | if (ret > 0) | |
1237 | wakeup_pipe_readers(opipe); | |
1238 | return ret; | |
1239 | } | |
1240 | ||
83f9135b JA |
1241 | /* |
1242 | * Determine where to splice to/from. | |
1243 | */ | |
ee6e00c8 JA |
1244 | long do_splice(struct file *in, loff_t *off_in, struct file *out, |
1245 | loff_t *off_out, size_t len, unsigned int flags) | |
5274f052 | 1246 | { |
7c77f0b3 MS |
1247 | struct pipe_inode_info *ipipe; |
1248 | struct pipe_inode_info *opipe; | |
7995bd28 | 1249 | loff_t offset; |
a4514ebd | 1250 | long ret; |
5274f052 | 1251 | |
90da2e3f PB |
1252 | if (unlikely(!(in->f_mode & FMODE_READ) || |
1253 | !(out->f_mode & FMODE_WRITE))) | |
1254 | return -EBADF; | |
1255 | ||
c73be61c DH |
1256 | ipipe = get_pipe_info(in, true); |
1257 | opipe = get_pipe_info(out, true); | |
7c77f0b3 MS |
1258 | |
1259 | if (ipipe && opipe) { | |
1260 | if (off_in || off_out) | |
1261 | return -ESPIPE; | |
1262 | ||
7c77f0b3 MS |
1263 | /* Splicing to self would be fun, but... */ |
1264 | if (ipipe == opipe) | |
1265 | return -EINVAL; | |
1266 | ||
ee5e0011 SK |
1267 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
1268 | flags |= SPLICE_F_NONBLOCK; | |
1269 | ||
12ee4b66 AZ |
1270 | ret = splice_pipe_to_pipe(ipipe, opipe, len, flags); |
1271 | } else if (ipipe) { | |
529565dc IM |
1272 | if (off_in) |
1273 | return -ESPIPE; | |
b92ce558 | 1274 | if (off_out) { |
19c9a49b | 1275 | if (!(out->f_mode & FMODE_PWRITE)) |
b92ce558 | 1276 | return -EINVAL; |
ee6e00c8 | 1277 | offset = *off_out; |
7995bd28 AV |
1278 | } else { |
1279 | offset = out->f_pos; | |
1280 | } | |
529565dc | 1281 | |
18c67cb9 AV |
1282 | if (unlikely(out->f_flags & O_APPEND)) |
1283 | return -EINVAL; | |
1284 | ||
1285 | ret = rw_verify_area(WRITE, out, &offset, len); | |
1286 | if (unlikely(ret < 0)) | |
1287 | return ret; | |
1288 | ||
ee5e0011 SK |
1289 | if (in->f_flags & O_NONBLOCK) |
1290 | flags |= SPLICE_F_NONBLOCK; | |
1291 | ||
500368f7 | 1292 | file_start_write(out); |
7995bd28 | 1293 | ret = do_splice_from(ipipe, out, &offset, len, flags); |
500368f7 | 1294 | file_end_write(out); |
a4514ebd | 1295 | |
7995bd28 AV |
1296 | if (!off_out) |
1297 | out->f_pos = offset; | |
ee6e00c8 JA |
1298 | else |
1299 | *off_out = offset; | |
12ee4b66 | 1300 | } else if (opipe) { |
529565dc IM |
1301 | if (off_out) |
1302 | return -ESPIPE; | |
b92ce558 | 1303 | if (off_in) { |
19c9a49b | 1304 | if (!(in->f_mode & FMODE_PREAD)) |
b92ce558 | 1305 | return -EINVAL; |
ee6e00c8 | 1306 | offset = *off_in; |
7995bd28 AV |
1307 | } else { |
1308 | offset = in->f_pos; | |
1309 | } | |
529565dc | 1310 | |
ee5e0011 SK |
1311 | if (out->f_flags & O_NONBLOCK) |
1312 | flags |= SPLICE_F_NONBLOCK; | |
1313 | ||
faa97c48 | 1314 | ret = splice_file_to_pipe(in, opipe, &offset, len, flags); |
983652c6 | 1315 | |
7995bd28 AV |
1316 | if (!off_in) |
1317 | in->f_pos = offset; | |
ee6e00c8 JA |
1318 | else |
1319 | *off_in = offset; | |
12ee4b66 AZ |
1320 | } else { |
1321 | ret = -EINVAL; | |
1322 | } | |
a4514ebd | 1323 | |
12ee4b66 AZ |
1324 | if (ret > 0) { |
1325 | /* | |
1326 | * Generate modify out before access in: | |
1327 | * do_splice_from() may've already sent modify out, | |
1328 | * and this ensures the events get merged. | |
1329 | */ | |
1330 | fsnotify_modify(out); | |
1331 | fsnotify_access(in); | |
529565dc | 1332 | } |
5274f052 | 1333 | |
12ee4b66 | 1334 | return ret; |
5274f052 JA |
1335 | } |
1336 | ||
ee6e00c8 JA |
1337 | static long __do_splice(struct file *in, loff_t __user *off_in, |
1338 | struct file *out, loff_t __user *off_out, | |
1339 | size_t len, unsigned int flags) | |
1340 | { | |
1341 | struct pipe_inode_info *ipipe; | |
1342 | struct pipe_inode_info *opipe; | |
1343 | loff_t offset, *__off_in = NULL, *__off_out = NULL; | |
1344 | long ret; | |
1345 | ||
1346 | ipipe = get_pipe_info(in, true); | |
1347 | opipe = get_pipe_info(out, true); | |
1348 | ||
0f99fc51 JA |
1349 | if (ipipe) { |
1350 | if (off_in) | |
1351 | return -ESPIPE; | |
1352 | pipe_clear_nowait(in); | |
1353 | } | |
1354 | if (opipe) { | |
1355 | if (off_out) | |
1356 | return -ESPIPE; | |
1357 | pipe_clear_nowait(out); | |
1358 | } | |
ee6e00c8 JA |
1359 | |
1360 | if (off_out) { | |
1361 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) | |
1362 | return -EFAULT; | |
1363 | __off_out = &offset; | |
1364 | } | |
1365 | if (off_in) { | |
1366 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) | |
1367 | return -EFAULT; | |
1368 | __off_in = &offset; | |
1369 | } | |
1370 | ||
1371 | ret = do_splice(in, __off_in, out, __off_out, len, flags); | |
1372 | if (ret < 0) | |
1373 | return ret; | |
1374 | ||
1375 | if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) | |
1376 | return -EFAULT; | |
1377 | if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) | |
1378 | return -EFAULT; | |
1379 | ||
1380 | return ret; | |
1381 | } | |
1382 | ||
79fddc4e AV |
1383 | static int iter_to_pipe(struct iov_iter *from, |
1384 | struct pipe_inode_info *pipe, | |
1385 | unsigned flags) | |
912d35f8 | 1386 | { |
79fddc4e AV |
1387 | struct pipe_buffer buf = { |
1388 | .ops = &user_page_pipe_buf_ops, | |
1389 | .flags = flags | |
1390 | }; | |
1391 | size_t total = 0; | |
1392 | int ret = 0; | |
79fddc4e | 1393 | |
7d690c15 | 1394 | while (iov_iter_count(from)) { |
79fddc4e | 1395 | struct page *pages[16]; |
7d690c15 | 1396 | ssize_t left; |
db85a9eb | 1397 | size_t start; |
7d690c15 | 1398 | int i, n; |
db85a9eb | 1399 | |
7d690c15 AV |
1400 | left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); |
1401 | if (left <= 0) { | |
1402 | ret = left; | |
79fddc4e AV |
1403 | break; |
1404 | } | |
db85a9eb | 1405 | |
7d690c15 AV |
1406 | n = DIV_ROUND_UP(left + start, PAGE_SIZE); |
1407 | for (i = 0; i < n; i++) { | |
1408 | int size = min_t(int, left, PAGE_SIZE - start); | |
1409 | ||
1410 | buf.page = pages[i]; | |
1411 | buf.offset = start; | |
1412 | buf.len = size; | |
1413 | ret = add_to_pipe(pipe, &buf); | |
1414 | if (unlikely(ret < 0)) { | |
1415 | iov_iter_revert(from, left); | |
1416 | // this one got dropped by add_to_pipe() | |
1417 | while (++i < n) | |
1418 | put_page(pages[i]); | |
1419 | goto out; | |
79fddc4e | 1420 | } |
7d690c15 AV |
1421 | total += ret; |
1422 | left -= size; | |
1423 | start = 0; | |
912d35f8 | 1424 | } |
912d35f8 | 1425 | } |
7d690c15 | 1426 | out: |
79fddc4e | 1427 | return total ? total : ret; |
912d35f8 JA |
1428 | } |
1429 | ||
6a14b90b JA |
1430 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
1431 | struct splice_desc *sd) | |
1432 | { | |
6130f531 AV |
1433 | int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); |
1434 | return n == sd->len ? n : -EFAULT; | |
6a14b90b JA |
1435 | } |
1436 | ||
1437 | /* | |
1438 | * For lack of a better implementation, implement vmsplice() to userspace | |
1439 | * as a simple copy of the pipes pages to the user iov. | |
1440 | */ | |
87a3002a AV |
1441 | static long vmsplice_to_user(struct file *file, struct iov_iter *iter, |
1442 | unsigned int flags) | |
6a14b90b | 1443 | { |
c73be61c | 1444 | struct pipe_inode_info *pipe = get_pipe_info(file, true); |
87a3002a AV |
1445 | struct splice_desc sd = { |
1446 | .total_len = iov_iter_count(iter), | |
1447 | .flags = flags, | |
1448 | .u.data = iter | |
1449 | }; | |
1450 | long ret = 0; | |
6a14b90b | 1451 | |
6a14b90b JA |
1452 | if (!pipe) |
1453 | return -EBADF; | |
1454 | ||
0f99fc51 JA |
1455 | pipe_clear_nowait(file); |
1456 | ||
345995fa AV |
1457 | if (sd.total_len) { |
1458 | pipe_lock(pipe); | |
1459 | ret = __splice_from_pipe(pipe, &sd, pipe_to_user); | |
1460 | pipe_unlock(pipe); | |
1461 | } | |
6a14b90b | 1462 | |
7f0f1ea0 AZ |
1463 | if (ret > 0) |
1464 | fsnotify_access(file); | |
1465 | ||
6a14b90b JA |
1466 | return ret; |
1467 | } | |
1468 | ||
912d35f8 JA |
1469 | /* |
1470 | * vmsplice splices a user address range into a pipe. It can be thought of | |
1471 | * as splice-from-memory, where the regular splice is splice-from-file (or | |
1472 | * to file). In both cases the output is a pipe, naturally. | |
912d35f8 | 1473 | */ |
87a3002a AV |
1474 | static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, |
1475 | unsigned int flags) | |
912d35f8 | 1476 | { |
ddac0d39 | 1477 | struct pipe_inode_info *pipe; |
87a3002a | 1478 | long ret = 0; |
79fddc4e AV |
1479 | unsigned buf_flag = 0; |
1480 | ||
1481 | if (flags & SPLICE_F_GIFT) | |
1482 | buf_flag = PIPE_BUF_FLAG_GIFT; | |
912d35f8 | 1483 | |
c73be61c | 1484 | pipe = get_pipe_info(file, true); |
ddac0d39 | 1485 | if (!pipe) |
912d35f8 | 1486 | return -EBADF; |
912d35f8 | 1487 | |
0f99fc51 JA |
1488 | pipe_clear_nowait(file); |
1489 | ||
8924feff AV |
1490 | pipe_lock(pipe); |
1491 | ret = wait_for_space(pipe, flags); | |
79fddc4e | 1492 | if (!ret) |
87a3002a | 1493 | ret = iter_to_pipe(iter, pipe, buf_flag); |
8924feff | 1494 | pipe_unlock(pipe); |
7f0f1ea0 | 1495 | if (ret > 0) { |
8924feff | 1496 | wakeup_pipe_readers(pipe); |
7f0f1ea0 AZ |
1497 | fsnotify_modify(file); |
1498 | } | |
35f3d14d | 1499 | return ret; |
912d35f8 JA |
1500 | } |
1501 | ||
87a3002a AV |
1502 | static int vmsplice_type(struct fd f, int *type) |
1503 | { | |
1504 | if (!f.file) | |
1505 | return -EBADF; | |
1506 | if (f.file->f_mode & FMODE_WRITE) { | |
de4eda9d | 1507 | *type = ITER_SOURCE; |
87a3002a | 1508 | } else if (f.file->f_mode & FMODE_READ) { |
de4eda9d | 1509 | *type = ITER_DEST; |
87a3002a AV |
1510 | } else { |
1511 | fdput(f); | |
1512 | return -EBADF; | |
1513 | } | |
1514 | return 0; | |
1515 | } | |
1516 | ||
6a14b90b JA |
1517 | /* |
1518 | * Note that vmsplice only really supports true splicing _from_ user memory | |
1519 | * to a pipe, not the other way around. Splicing from user memory is a simple | |
1520 | * operation that can be supported without any funky alignment restrictions | |
1521 | * or nasty vm tricks. We simply map in the user memory and fill them into | |
1522 | * a pipe. The reverse isn't quite as easy, though. There are two possible | |
1523 | * solutions for that: | |
1524 | * | |
1525 | * - memcpy() the data internally, at which point we might as well just | |
1526 | * do a regular read() on the buffer anyway. | |
1527 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it | |
1528 | * has restriction limitations on both ends of the pipe). | |
1529 | * | |
1530 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). | |
1531 | * | |
1532 | */ | |
87a3002a | 1533 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, |
30cfe4ef DB |
1534 | unsigned long, nr_segs, unsigned int, flags) |
1535 | { | |
87a3002a AV |
1536 | struct iovec iovstack[UIO_FASTIOV]; |
1537 | struct iovec *iov = iovstack; | |
1538 | struct iov_iter iter; | |
87e5e6da | 1539 | ssize_t error; |
87a3002a AV |
1540 | struct fd f; |
1541 | int type; | |
1542 | ||
598b3cec CH |
1543 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1544 | return -EINVAL; | |
1545 | ||
87a3002a AV |
1546 | f = fdget(fd); |
1547 | error = vmsplice_type(f, &type); | |
1548 | if (error) | |
1549 | return error; | |
1550 | ||
1551 | error = import_iovec(type, uiov, nr_segs, | |
1552 | ARRAY_SIZE(iovstack), &iov, &iter); | |
598b3cec CH |
1553 | if (error < 0) |
1554 | goto out_fdput; | |
30cfe4ef | 1555 | |
598b3cec CH |
1556 | if (!iov_iter_count(&iter)) |
1557 | error = 0; | |
de4eda9d | 1558 | else if (type == ITER_SOURCE) |
598b3cec CH |
1559 | error = vmsplice_to_pipe(f.file, &iter, flags); |
1560 | else | |
1561 | error = vmsplice_to_user(f.file, &iter, flags); | |
87a3002a | 1562 | |
598b3cec CH |
1563 | kfree(iov); |
1564 | out_fdput: | |
87a3002a AV |
1565 | fdput(f); |
1566 | return error; | |
76b021d0 | 1567 | } |
76b021d0 | 1568 | |
836f92ad HC |
1569 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
1570 | int, fd_out, loff_t __user *, off_out, | |
1571 | size_t, len, unsigned int, flags) | |
5274f052 | 1572 | { |
2903ff01 | 1573 | struct fd in, out; |
5274f052 | 1574 | long error; |
5274f052 JA |
1575 | |
1576 | if (unlikely(!len)) | |
1577 | return 0; | |
1578 | ||
3d6ea290 AV |
1579 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1580 | return -EINVAL; | |
1581 | ||
5274f052 | 1582 | error = -EBADF; |
2903ff01 AV |
1583 | in = fdget(fd_in); |
1584 | if (in.file) { | |
90da2e3f PB |
1585 | out = fdget(fd_out); |
1586 | if (out.file) { | |
ee6e00c8 JA |
1587 | error = __do_splice(in.file, off_in, out.file, off_out, |
1588 | len, flags); | |
90da2e3f | 1589 | fdput(out); |
5274f052 | 1590 | } |
2903ff01 | 1591 | fdput(in); |
5274f052 | 1592 | } |
5274f052 JA |
1593 | return error; |
1594 | } | |
70524490 | 1595 | |
aadd06e5 JA |
1596 | /* |
1597 | * Make sure there's data to read. Wait for input if we can, otherwise | |
1598 | * return an appropriate error. | |
1599 | */ | |
7c77f0b3 | 1600 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
aadd06e5 JA |
1601 | { |
1602 | int ret; | |
1603 | ||
1604 | /* | |
8cefc107 | 1605 | * Check the pipe occupancy without the inode lock first. This function |
aadd06e5 JA |
1606 | * is speculative anyways, so missing one is ok. |
1607 | */ | |
8cefc107 | 1608 | if (!pipe_empty(pipe->head, pipe->tail)) |
aadd06e5 JA |
1609 | return 0; |
1610 | ||
1611 | ret = 0; | |
61e0d47c | 1612 | pipe_lock(pipe); |
aadd06e5 | 1613 | |
8cefc107 | 1614 | while (pipe_empty(pipe->head, pipe->tail)) { |
aadd06e5 JA |
1615 | if (signal_pending(current)) { |
1616 | ret = -ERESTARTSYS; | |
1617 | break; | |
1618 | } | |
1619 | if (!pipe->writers) | |
1620 | break; | |
a28c8b9d LT |
1621 | if (flags & SPLICE_F_NONBLOCK) { |
1622 | ret = -EAGAIN; | |
1623 | break; | |
aadd06e5 | 1624 | } |
472e5b05 | 1625 | pipe_wait_readable(pipe); |
aadd06e5 JA |
1626 | } |
1627 | ||
61e0d47c | 1628 | pipe_unlock(pipe); |
aadd06e5 JA |
1629 | return ret; |
1630 | } | |
1631 | ||
1632 | /* | |
1633 | * Make sure there's writeable room. Wait for room if we can, otherwise | |
1634 | * return an appropriate error. | |
1635 | */ | |
7c77f0b3 | 1636 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
aadd06e5 JA |
1637 | { |
1638 | int ret; | |
1639 | ||
1640 | /* | |
8cefc107 | 1641 | * Check pipe occupancy without the inode lock first. This function |
aadd06e5 JA |
1642 | * is speculative anyways, so missing one is ok. |
1643 | */ | |
566d1362 | 1644 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
aadd06e5 JA |
1645 | return 0; |
1646 | ||
1647 | ret = 0; | |
61e0d47c | 1648 | pipe_lock(pipe); |
aadd06e5 | 1649 | |
6718b6f8 | 1650 | while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { |
aadd06e5 JA |
1651 | if (!pipe->readers) { |
1652 | send_sig(SIGPIPE, current, 0); | |
1653 | ret = -EPIPE; | |
1654 | break; | |
1655 | } | |
1656 | if (flags & SPLICE_F_NONBLOCK) { | |
1657 | ret = -EAGAIN; | |
1658 | break; | |
1659 | } | |
1660 | if (signal_pending(current)) { | |
1661 | ret = -ERESTARTSYS; | |
1662 | break; | |
1663 | } | |
472e5b05 | 1664 | pipe_wait_writable(pipe); |
aadd06e5 JA |
1665 | } |
1666 | ||
61e0d47c | 1667 | pipe_unlock(pipe); |
aadd06e5 JA |
1668 | return ret; |
1669 | } | |
1670 | ||
7c77f0b3 MS |
1671 | /* |
1672 | * Splice contents of ipipe to opipe. | |
1673 | */ | |
1674 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, | |
1675 | struct pipe_inode_info *opipe, | |
1676 | size_t len, unsigned int flags) | |
1677 | { | |
1678 | struct pipe_buffer *ibuf, *obuf; | |
8cefc107 DH |
1679 | unsigned int i_head, o_head; |
1680 | unsigned int i_tail, o_tail; | |
1681 | unsigned int i_mask, o_mask; | |
1682 | int ret = 0; | |
7c77f0b3 MS |
1683 | bool input_wakeup = false; |
1684 | ||
1685 | ||
1686 | retry: | |
1687 | ret = ipipe_prep(ipipe, flags); | |
1688 | if (ret) | |
1689 | return ret; | |
1690 | ||
1691 | ret = opipe_prep(opipe, flags); | |
1692 | if (ret) | |
1693 | return ret; | |
1694 | ||
1695 | /* | |
1696 | * Potential ABBA deadlock, work around it by ordering lock | |
1697 | * grabbing by pipe info address. Otherwise two different processes | |
1698 | * could deadlock (one doing tee from A -> B, the other from B -> A). | |
1699 | */ | |
1700 | pipe_double_lock(ipipe, opipe); | |
1701 | ||
8cefc107 DH |
1702 | i_tail = ipipe->tail; |
1703 | i_mask = ipipe->ring_size - 1; | |
1704 | o_head = opipe->head; | |
1705 | o_mask = opipe->ring_size - 1; | |
1706 | ||
7c77f0b3 | 1707 | do { |
8cefc107 DH |
1708 | size_t o_len; |
1709 | ||
7c77f0b3 MS |
1710 | if (!opipe->readers) { |
1711 | send_sig(SIGPIPE, current, 0); | |
1712 | if (!ret) | |
1713 | ret = -EPIPE; | |
1714 | break; | |
1715 | } | |
1716 | ||
8cefc107 DH |
1717 | i_head = ipipe->head; |
1718 | o_tail = opipe->tail; | |
1719 | ||
1720 | if (pipe_empty(i_head, i_tail) && !ipipe->writers) | |
7c77f0b3 MS |
1721 | break; |
1722 | ||
1723 | /* | |
1724 | * Cannot make any progress, because either the input | |
1725 | * pipe is empty or the output pipe is full. | |
1726 | */ | |
8cefc107 | 1727 | if (pipe_empty(i_head, i_tail) || |
6718b6f8 | 1728 | pipe_full(o_head, o_tail, opipe->max_usage)) { |
7c77f0b3 MS |
1729 | /* Already processed some buffers, break */ |
1730 | if (ret) | |
1731 | break; | |
1732 | ||
1733 | if (flags & SPLICE_F_NONBLOCK) { | |
1734 | ret = -EAGAIN; | |
1735 | break; | |
1736 | } | |
1737 | ||
1738 | /* | |
1739 | * We raced with another reader/writer and haven't | |
1740 | * managed to process any buffers. A zero return | |
1741 | * value means EOF, so retry instead. | |
1742 | */ | |
1743 | pipe_unlock(ipipe); | |
1744 | pipe_unlock(opipe); | |
1745 | goto retry; | |
1746 | } | |
1747 | ||
8cefc107 DH |
1748 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
1749 | obuf = &opipe->bufs[o_head & o_mask]; | |
7c77f0b3 MS |
1750 | |
1751 | if (len >= ibuf->len) { | |
1752 | /* | |
1753 | * Simply move the whole buffer from ipipe to opipe | |
1754 | */ | |
1755 | *obuf = *ibuf; | |
1756 | ibuf->ops = NULL; | |
8cefc107 DH |
1757 | i_tail++; |
1758 | ipipe->tail = i_tail; | |
7c77f0b3 | 1759 | input_wakeup = true; |
8cefc107 DH |
1760 | o_len = obuf->len; |
1761 | o_head++; | |
1762 | opipe->head = o_head; | |
7c77f0b3 MS |
1763 | } else { |
1764 | /* | |
1765 | * Get a reference to this pipe buffer, | |
1766 | * so we can copy the contents over. | |
1767 | */ | |
15fab63e MW |
1768 | if (!pipe_buf_get(ipipe, ibuf)) { |
1769 | if (ret == 0) | |
1770 | ret = -EFAULT; | |
1771 | break; | |
1772 | } | |
7c77f0b3 MS |
1773 | *obuf = *ibuf; |
1774 | ||
1775 | /* | |
f6dd9755 | 1776 | * Don't inherit the gift and merge flags, we need to |
7c77f0b3 MS |
1777 | * prevent multiple steals of this page. |
1778 | */ | |
1779 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; | |
f6dd9755 | 1780 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
a0ce2f0a | 1781 | |
7c77f0b3 | 1782 | obuf->len = len; |
8cefc107 DH |
1783 | ibuf->offset += len; |
1784 | ibuf->len -= len; | |
1785 | o_len = len; | |
1786 | o_head++; | |
1787 | opipe->head = o_head; | |
7c77f0b3 | 1788 | } |
8cefc107 DH |
1789 | ret += o_len; |
1790 | len -= o_len; | |
7c77f0b3 MS |
1791 | } while (len); |
1792 | ||
1793 | pipe_unlock(ipipe); | |
1794 | pipe_unlock(opipe); | |
1795 | ||
1796 | /* | |
1797 | * If we put data in the output pipe, wakeup any potential readers. | |
1798 | */ | |
825cdcb1 NK |
1799 | if (ret > 0) |
1800 | wakeup_pipe_readers(opipe); | |
1801 | ||
7c77f0b3 MS |
1802 | if (input_wakeup) |
1803 | wakeup_pipe_writers(ipipe); | |
1804 | ||
1805 | return ret; | |
1806 | } | |
1807 | ||
70524490 JA |
1808 | /* |
1809 | * Link contents of ipipe to opipe. | |
1810 | */ | |
1811 | static int link_pipe(struct pipe_inode_info *ipipe, | |
1812 | struct pipe_inode_info *opipe, | |
1813 | size_t len, unsigned int flags) | |
1814 | { | |
1815 | struct pipe_buffer *ibuf, *obuf; | |
8cefc107 DH |
1816 | unsigned int i_head, o_head; |
1817 | unsigned int i_tail, o_tail; | |
1818 | unsigned int i_mask, o_mask; | |
1819 | int ret = 0; | |
70524490 JA |
1820 | |
1821 | /* | |
1822 | * Potential ABBA deadlock, work around it by ordering lock | |
61e0d47c | 1823 | * grabbing by pipe info address. Otherwise two different processes |
70524490 JA |
1824 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
1825 | */ | |
61e0d47c | 1826 | pipe_double_lock(ipipe, opipe); |
70524490 | 1827 | |
8cefc107 DH |
1828 | i_tail = ipipe->tail; |
1829 | i_mask = ipipe->ring_size - 1; | |
1830 | o_head = opipe->head; | |
1831 | o_mask = opipe->ring_size - 1; | |
1832 | ||
aadd06e5 | 1833 | do { |
70524490 JA |
1834 | if (!opipe->readers) { |
1835 | send_sig(SIGPIPE, current, 0); | |
1836 | if (!ret) | |
1837 | ret = -EPIPE; | |
1838 | break; | |
1839 | } | |
70524490 | 1840 | |
8cefc107 DH |
1841 | i_head = ipipe->head; |
1842 | o_tail = opipe->tail; | |
1843 | ||
aadd06e5 | 1844 | /* |
8cefc107 | 1845 | * If we have iterated all input buffers or run out of |
aadd06e5 JA |
1846 | * output room, break. |
1847 | */ | |
8cefc107 | 1848 | if (pipe_empty(i_head, i_tail) || |
6718b6f8 | 1849 | pipe_full(o_head, o_tail, opipe->max_usage)) |
aadd06e5 | 1850 | break; |
70524490 | 1851 | |
8cefc107 DH |
1852 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
1853 | obuf = &opipe->bufs[o_head & o_mask]; | |
70524490 JA |
1854 | |
1855 | /* | |
aadd06e5 JA |
1856 | * Get a reference to this pipe buffer, |
1857 | * so we can copy the contents over. | |
70524490 | 1858 | */ |
15fab63e MW |
1859 | if (!pipe_buf_get(ipipe, ibuf)) { |
1860 | if (ret == 0) | |
1861 | ret = -EFAULT; | |
1862 | break; | |
1863 | } | |
aadd06e5 | 1864 | |
aadd06e5 JA |
1865 | *obuf = *ibuf; |
1866 | ||
2a27250e | 1867 | /* |
f6dd9755 CH |
1868 | * Don't inherit the gift and merge flag, we need to prevent |
1869 | * multiple steals of this page. | |
2a27250e | 1870 | */ |
aadd06e5 | 1871 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
f6dd9755 | 1872 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
a0ce2f0a | 1873 | |
aadd06e5 JA |
1874 | if (obuf->len > len) |
1875 | obuf->len = len; | |
aadd06e5 JA |
1876 | ret += obuf->len; |
1877 | len -= obuf->len; | |
8cefc107 DH |
1878 | |
1879 | o_head++; | |
1880 | opipe->head = o_head; | |
1881 | i_tail++; | |
aadd06e5 | 1882 | } while (len); |
70524490 | 1883 | |
61e0d47c MS |
1884 | pipe_unlock(ipipe); |
1885 | pipe_unlock(opipe); | |
70524490 | 1886 | |
aadd06e5 JA |
1887 | /* |
1888 | * If we put data in the output pipe, wakeup any potential readers. | |
1889 | */ | |
825cdcb1 NK |
1890 | if (ret > 0) |
1891 | wakeup_pipe_readers(opipe); | |
70524490 JA |
1892 | |
1893 | return ret; | |
1894 | } | |
1895 | ||
1896 | /* | |
1897 | * This is a tee(1) implementation that works on pipes. It doesn't copy | |
1898 | * any data, it simply references the 'in' pages on the 'out' pipe. | |
1899 | * The 'flags' used are the SPLICE_F_* variants, currently the only | |
1900 | * applicable one is SPLICE_F_NONBLOCK. | |
1901 | */ | |
9dafdfc2 | 1902 | long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) |
70524490 | 1903 | { |
c73be61c DH |
1904 | struct pipe_inode_info *ipipe = get_pipe_info(in, true); |
1905 | struct pipe_inode_info *opipe = get_pipe_info(out, true); | |
aadd06e5 | 1906 | int ret = -EINVAL; |
70524490 | 1907 | |
90da2e3f PB |
1908 | if (unlikely(!(in->f_mode & FMODE_READ) || |
1909 | !(out->f_mode & FMODE_WRITE))) | |
1910 | return -EBADF; | |
1911 | ||
70524490 | 1912 | /* |
aadd06e5 JA |
1913 | * Duplicate the contents of ipipe to opipe without actually |
1914 | * copying the data. | |
70524490 | 1915 | */ |
aadd06e5 | 1916 | if (ipipe && opipe && ipipe != opipe) { |
ee5e0011 SK |
1917 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
1918 | flags |= SPLICE_F_NONBLOCK; | |
1919 | ||
aadd06e5 JA |
1920 | /* |
1921 | * Keep going, unless we encounter an error. The ipipe/opipe | |
1922 | * ordering doesn't really matter. | |
1923 | */ | |
7c77f0b3 | 1924 | ret = ipipe_prep(ipipe, flags); |
aadd06e5 | 1925 | if (!ret) { |
7c77f0b3 | 1926 | ret = opipe_prep(opipe, flags); |
02cf01ae | 1927 | if (!ret) |
aadd06e5 | 1928 | ret = link_pipe(ipipe, opipe, len, flags); |
aadd06e5 JA |
1929 | } |
1930 | } | |
70524490 | 1931 | |
576d498e AZ |
1932 | if (ret > 0) { |
1933 | fsnotify_access(in); | |
1934 | fsnotify_modify(out); | |
1935 | } | |
1936 | ||
aadd06e5 | 1937 | return ret; |
70524490 JA |
1938 | } |
1939 | ||
836f92ad | 1940 | SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) |
70524490 | 1941 | { |
90da2e3f | 1942 | struct fd in, out; |
2903ff01 | 1943 | int error; |
70524490 | 1944 | |
3d6ea290 AV |
1945 | if (unlikely(flags & ~SPLICE_F_ALL)) |
1946 | return -EINVAL; | |
1947 | ||
70524490 JA |
1948 | if (unlikely(!len)) |
1949 | return 0; | |
1950 | ||
1951 | error = -EBADF; | |
2903ff01 AV |
1952 | in = fdget(fdin); |
1953 | if (in.file) { | |
90da2e3f PB |
1954 | out = fdget(fdout); |
1955 | if (out.file) { | |
1956 | error = do_tee(in.file, out.file, len, flags); | |
1957 | fdput(out); | |
70524490 | 1958 | } |
2903ff01 | 1959 | fdput(in); |
70524490 JA |
1960 | } |
1961 | ||
1962 | return error; | |
1963 | } |