blob: c010a72ca2d2a3543fb2a7365b2e8c5b4c73b652 [file] [log] [blame]
Jens Axboe5274f052006-03-30 15:15:30 +02001/*
2 * "splice": joining two ropes together by interweaving their strands.
3 *
4 * This is the "extended pipe" functionality, where a pipe is used as
5 * an arbitrary in-memory buffer. Think of a pipe as a small kernel
6 * buffer that you can use to transfer data from one end to the other.
7 *
8 * The traditional unix read/write is extended with a "splice()" operation
9 * that transfers data buffers to or from a pipe buffer.
10 *
11 * Named by Larry McVoy, original implementation from Linus, extended by
Jens Axboec2058e02006-04-11 13:56:34 +020012 * Jens to support splicing to files, network, direct splicing, etc and
13 * fixing lots of bugs.
Jens Axboe5274f052006-03-30 15:15:30 +020014 *
Jens Axboe0fe23472006-09-04 15:41:16 +020015 * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk>
Jens Axboec2058e02006-04-11 13:56:34 +020016 * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org>
17 * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu>
Jens Axboe5274f052006-03-30 15:15:30 +020018 *
19 */
20#include <linux/fs.h>
21#include <linux/file.h>
22#include <linux/pagemap.h>
Jens Axboed6b29d72007-06-04 09:59:47 +020023#include <linux/splice.h>
Jens Axboe5274f052006-03-30 15:15:30 +020024#include <linux/mm_inline.h>
Jens Axboe5abc97a2006-03-30 15:16:46 +020025#include <linux/swap.h>
Jens Axboe4f6f0bd2006-04-02 23:04:46 +020026#include <linux/writeback.h>
27#include <linux/buffer_head.h>
Jeff Garzika0f06782006-03-30 23:06:13 -050028#include <linux/module.h>
Jens Axboe4f6f0bd2006-04-02 23:04:46 +020029#include <linux/syscalls.h>
Jens Axboe912d35f2006-04-26 10:59:21 +020030#include <linux/uio.h>
James Morris29ce2052007-07-13 11:44:32 +020031#include <linux/security.h>
Jens Axboe5274f052006-03-30 15:15:30 +020032
Jens Axboe83f91352006-04-02 23:05:09 +020033/*
34 * Attempt to steal a page from a pipe buffer. This should perhaps go into
35 * a vm helper function, it's already simplified quite a bit by the
36 * addition of remove_mapping(). If success is returned, the caller may
37 * attempt to reuse this page for another destination.
38 */
Jens Axboe76ad4d12006-05-03 10:41:33 +020039static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
Jens Axboe5abc97a2006-03-30 15:16:46 +020040 struct pipe_buffer *buf)
41{
42 struct page *page = buf->page;
Jens Axboe9e94cd42006-06-20 15:01:12 +020043 struct address_space *mapping;
Jens Axboe5abc97a2006-03-30 15:16:46 +020044
Jens Axboe9e0267c2006-04-19 15:57:31 +020045 lock_page(page);
46
Jens Axboe9e94cd42006-06-20 15:01:12 +020047 mapping = page_mapping(page);
48 if (mapping) {
49 WARN_ON(!PageUptodate(page));
Jens Axboe5abc97a2006-03-30 15:16:46 +020050
Jens Axboe9e94cd42006-06-20 15:01:12 +020051 /*
52 * At least for ext2 with nobh option, we need to wait on
53 * writeback completing on this page, since we'll remove it
54 * from the pagecache. Otherwise truncate wont wait on the
55 * page, allowing the disk blocks to be reused by someone else
56 * before we actually wrote our data to them. fs corruption
57 * ensues.
58 */
59 wait_on_page_writeback(page);
Jens Axboead8d6f02006-04-02 23:10:32 +020060
Jens Axboe9e94cd42006-06-20 15:01:12 +020061 if (PagePrivate(page))
Nick Piggin2ae88142006-10-28 10:38:23 -070062 try_to_release_page(page, GFP_KERNEL);
Jens Axboe4f6f0bd2006-04-02 23:04:46 +020063
Jens Axboe9e94cd42006-06-20 15:01:12 +020064 /*
65 * If we succeeded in removing the mapping, set LRU flag
66 * and return good.
67 */
68 if (remove_mapping(mapping, page)) {
69 buf->flags |= PIPE_BUF_FLAG_LRU;
70 return 0;
71 }
Jens Axboe9e0267c2006-04-19 15:57:31 +020072 }
Jens Axboe5abc97a2006-03-30 15:16:46 +020073
Jens Axboe9e94cd42006-06-20 15:01:12 +020074 /*
75 * Raced with truncate or failed to remove page from current
76 * address space, unlock and return failure.
77 */
78 unlock_page(page);
79 return 1;
Jens Axboe5abc97a2006-03-30 15:16:46 +020080}
81
Jens Axboe76ad4d12006-05-03 10:41:33 +020082static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
Jens Axboe5274f052006-03-30 15:15:30 +020083 struct pipe_buffer *buf)
84{
85 page_cache_release(buf->page);
Jens Axboe14328732006-05-03 10:35:26 +020086 buf->flags &= ~PIPE_BUF_FLAG_LRU;
Jens Axboe5274f052006-03-30 15:15:30 +020087}
88
Jens Axboe08457182007-06-12 20:51:32 +020089/*
90 * Check whether the contents of buf is OK to access. Since the content
91 * is a page cache page, IO may be in flight.
92 */
Jens Axboecac36bb2007-06-14 13:10:48 +020093static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
94 struct pipe_buffer *buf)
Jens Axboe5274f052006-03-30 15:15:30 +020095{
96 struct page *page = buf->page;
Jens Axboe49d0b212006-04-10 09:04:41 +020097 int err;
Jens Axboe5274f052006-03-30 15:15:30 +020098
99 if (!PageUptodate(page)) {
Jens Axboe49d0b212006-04-10 09:04:41 +0200100 lock_page(page);
101
102 /*
103 * Page got truncated/unhashed. This will cause a 0-byte
Ingo Molnar73d62d82006-04-11 13:57:21 +0200104 * splice, if this is the first page.
Jens Axboe49d0b212006-04-10 09:04:41 +0200105 */
106 if (!page->mapping) {
107 err = -ENODATA;
108 goto error;
109 }
110
111 /*
Ingo Molnar73d62d82006-04-11 13:57:21 +0200112 * Uh oh, read-error from disk.
Jens Axboe49d0b212006-04-10 09:04:41 +0200113 */
114 if (!PageUptodate(page)) {
115 err = -EIO;
116 goto error;
117 }
118
119 /*
Jens Axboef84d7512006-05-01 19:59:03 +0200120 * Page is ok afterall, we are done.
Jens Axboe49d0b212006-04-10 09:04:41 +0200121 */
Jens Axboe5274f052006-03-30 15:15:30 +0200122 unlock_page(page);
Jens Axboe5274f052006-03-30 15:15:30 +0200123 }
124
Jens Axboef84d7512006-05-01 19:59:03 +0200125 return 0;
Jens Axboe49d0b212006-04-10 09:04:41 +0200126error:
127 unlock_page(page);
Jens Axboef84d7512006-05-01 19:59:03 +0200128 return err;
Jens Axboe70524492006-04-11 15:51:17 +0200129}
130
Eric Dumazetd4c3cca2006-12-13 00:34:04 -0800131static const struct pipe_buf_operations page_cache_pipe_buf_ops = {
Jens Axboe5274f052006-03-30 15:15:30 +0200132 .can_merge = 0,
Jens Axboef84d7512006-05-01 19:59:03 +0200133 .map = generic_pipe_buf_map,
134 .unmap = generic_pipe_buf_unmap,
Jens Axboecac36bb2007-06-14 13:10:48 +0200135 .confirm = page_cache_pipe_buf_confirm,
Jens Axboe5274f052006-03-30 15:15:30 +0200136 .release = page_cache_pipe_buf_release,
Jens Axboe5abc97a2006-03-30 15:16:46 +0200137 .steal = page_cache_pipe_buf_steal,
Jens Axboef84d7512006-05-01 19:59:03 +0200138 .get = generic_pipe_buf_get,
Jens Axboe5274f052006-03-30 15:15:30 +0200139};
140
Jens Axboe912d35f2006-04-26 10:59:21 +0200141static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
142 struct pipe_buffer *buf)
143{
Jens Axboe7afa6fd2006-05-01 20:02:33 +0200144 if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
145 return 1;
146
Jens Axboe14328732006-05-03 10:35:26 +0200147 buf->flags |= PIPE_BUF_FLAG_LRU;
Jens Axboe330ab712006-05-02 15:29:57 +0200148 return generic_pipe_buf_steal(pipe, buf);
Jens Axboe912d35f2006-04-26 10:59:21 +0200149}
150
Eric Dumazetd4c3cca2006-12-13 00:34:04 -0800151static const struct pipe_buf_operations user_page_pipe_buf_ops = {
Jens Axboe912d35f2006-04-26 10:59:21 +0200152 .can_merge = 0,
Jens Axboef84d7512006-05-01 19:59:03 +0200153 .map = generic_pipe_buf_map,
154 .unmap = generic_pipe_buf_unmap,
Jens Axboecac36bb2007-06-14 13:10:48 +0200155 .confirm = generic_pipe_buf_confirm,
Jens Axboe912d35f2006-04-26 10:59:21 +0200156 .release = page_cache_pipe_buf_release,
157 .steal = user_page_pipe_buf_steal,
Jens Axboef84d7512006-05-01 19:59:03 +0200158 .get = generic_pipe_buf_get,
Jens Axboe912d35f2006-04-26 10:59:21 +0200159};
160
Jens Axboe932cc6d2007-06-21 13:10:21 +0200161/**
162 * splice_to_pipe - fill passed data into a pipe
163 * @pipe: pipe to fill
164 * @spd: data to fill
165 *
166 * Description:
Randy Dunlap79685b82007-07-27 08:08:51 +0200167 * @spd contains a map of pages and len/offset tuples, along with
Jens Axboe932cc6d2007-06-21 13:10:21 +0200168 * the struct pipe_buf_operations associated with these pages. This
169 * function will link that data to the pipe.
170 *
Jens Axboe83f91352006-04-02 23:05:09 +0200171 */
Jens Axboed6b29d72007-06-04 09:59:47 +0200172ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
173 struct splice_pipe_desc *spd)
Jens Axboe5274f052006-03-30 15:15:30 +0200174{
Jens Axboe00de00b2007-06-15 13:14:22 +0200175 unsigned int spd_pages = spd->nr_pages;
Jens Axboe912d35f2006-04-26 10:59:21 +0200176 int ret, do_wakeup, page_nr;
Jens Axboe5274f052006-03-30 15:15:30 +0200177
178 ret = 0;
179 do_wakeup = 0;
Jens Axboe912d35f2006-04-26 10:59:21 +0200180 page_nr = 0;
Jens Axboe5274f052006-03-30 15:15:30 +0200181
Ingo Molnar3a326a22006-04-10 15:18:35 +0200182 if (pipe->inode)
183 mutex_lock(&pipe->inode->i_mutex);
Jens Axboe5274f052006-03-30 15:15:30 +0200184
Jens Axboe5274f052006-03-30 15:15:30 +0200185 for (;;) {
Ingo Molnar3a326a22006-04-10 15:18:35 +0200186 if (!pipe->readers) {
Jens Axboe5274f052006-03-30 15:15:30 +0200187 send_sig(SIGPIPE, current, 0);
188 if (!ret)
189 ret = -EPIPE;
190 break;
191 }
192
Jens Axboe6f767b02006-04-11 13:53:56 +0200193 if (pipe->nrbufs < PIPE_BUFFERS) {
194 int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
Ingo Molnar3a326a22006-04-10 15:18:35 +0200195 struct pipe_buffer *buf = pipe->bufs + newbuf;
Jens Axboe5274f052006-03-30 15:15:30 +0200196
Jens Axboe912d35f2006-04-26 10:59:21 +0200197 buf->page = spd->pages[page_nr];
198 buf->offset = spd->partial[page_nr].offset;
199 buf->len = spd->partial[page_nr].len;
Jens Axboe497f9622007-06-11 12:00:45 +0200200 buf->private = spd->partial[page_nr].private;
Jens Axboe912d35f2006-04-26 10:59:21 +0200201 buf->ops = spd->ops;
Jens Axboe7afa6fd2006-05-01 20:02:33 +0200202 if (spd->flags & SPLICE_F_GIFT)
203 buf->flags |= PIPE_BUF_FLAG_GIFT;
204
Jens Axboe6f767b02006-04-11 13:53:56 +0200205 pipe->nrbufs++;
Jens Axboe912d35f2006-04-26 10:59:21 +0200206 page_nr++;
207 ret += buf->len;
208
Jens Axboe6f767b02006-04-11 13:53:56 +0200209 if (pipe->inode)
210 do_wakeup = 1;
Jens Axboe5274f052006-03-30 15:15:30 +0200211
Jens Axboe912d35f2006-04-26 10:59:21 +0200212 if (!--spd->nr_pages)
Jens Axboe5274f052006-03-30 15:15:30 +0200213 break;
Jens Axboe6f767b02006-04-11 13:53:56 +0200214 if (pipe->nrbufs < PIPE_BUFFERS)
Jens Axboe5274f052006-03-30 15:15:30 +0200215 continue;
216
217 break;
218 }
219
Jens Axboe912d35f2006-04-26 10:59:21 +0200220 if (spd->flags & SPLICE_F_NONBLOCK) {
Linus Torvalds29e35092006-04-02 12:46:35 -0700221 if (!ret)
222 ret = -EAGAIN;
223 break;
224 }
225
Jens Axboe5274f052006-03-30 15:15:30 +0200226 if (signal_pending(current)) {
227 if (!ret)
228 ret = -ERESTARTSYS;
229 break;
230 }
231
232 if (do_wakeup) {
Jens Axboec0bd1f62006-04-10 09:03:32 +0200233 smp_mb();
Ingo Molnar3a326a22006-04-10 15:18:35 +0200234 if (waitqueue_active(&pipe->wait))
235 wake_up_interruptible_sync(&pipe->wait);
236 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
Jens Axboe5274f052006-03-30 15:15:30 +0200237 do_wakeup = 0;
238 }
239
Ingo Molnar3a326a22006-04-10 15:18:35 +0200240 pipe->waiting_writers++;
241 pipe_wait(pipe);
242 pipe->waiting_writers--;
Jens Axboe5274f052006-03-30 15:15:30 +0200243 }
244
Jens Axboe02676e52007-06-15 13:16:13 +0200245 if (pipe->inode) {
Ingo Molnar3a326a22006-04-10 15:18:35 +0200246 mutex_unlock(&pipe->inode->i_mutex);
Jens Axboe5274f052006-03-30 15:15:30 +0200247
Jens Axboe02676e52007-06-15 13:16:13 +0200248 if (do_wakeup) {
249 smp_mb();
250 if (waitqueue_active(&pipe->wait))
251 wake_up_interruptible(&pipe->wait);
252 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
253 }
Jens Axboe5274f052006-03-30 15:15:30 +0200254 }
255
Jens Axboe00de00b2007-06-15 13:14:22 +0200256 while (page_nr < spd_pages)
Jens Axboe912d35f2006-04-26 10:59:21 +0200257 page_cache_release(spd->pages[page_nr++]);
Jens Axboe5274f052006-03-30 15:15:30 +0200258
259 return ret;
260}
261
Ingo Molnar3a326a22006-04-10 15:18:35 +0200262static int
Jens Axboecbb7e572006-04-11 14:57:50 +0200263__generic_file_splice_read(struct file *in, loff_t *ppos,
264 struct pipe_inode_info *pipe, size_t len,
265 unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200266{
267 struct address_space *mapping = in->f_mapping;
Fengguang Wud8983912007-07-19 01:48:06 -0700268 unsigned int loff, nr_pages, req_pages;
Jens Axboe16c523d2006-04-10 09:03:58 +0200269 struct page *pages[PIPE_BUFFERS];
Jens Axboe912d35f2006-04-26 10:59:21 +0200270 struct partial_page partial[PIPE_BUFFERS];
Jens Axboe5274f052006-03-30 15:15:30 +0200271 struct page *page;
Jens Axboe91ad66e2006-04-19 15:55:10 +0200272 pgoff_t index, end_index;
273 loff_t isize;
Jens Axboeeb207962006-04-27 11:05:22 +0200274 int error, page_nr;
Jens Axboe912d35f2006-04-26 10:59:21 +0200275 struct splice_pipe_desc spd = {
276 .pages = pages,
277 .partial = partial,
278 .flags = flags,
279 .ops = &page_cache_pipe_buf_ops,
280 };
Jens Axboe5274f052006-03-30 15:15:30 +0200281
Jens Axboecbb7e572006-04-11 14:57:50 +0200282 index = *ppos >> PAGE_CACHE_SHIFT;
Jens Axboe912d35f2006-04-26 10:59:21 +0200283 loff = *ppos & ~PAGE_CACHE_MASK;
Fengguang Wud8983912007-07-19 01:48:06 -0700284 req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
285 nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS);
Jens Axboe5274f052006-03-30 15:15:30 +0200286
287 /*
Jens Axboeeb207962006-04-27 11:05:22 +0200288 * Lookup the (hopefully) full range of pages we need.
289 */
290 spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages);
Fengguang Wu431a4822007-07-19 01:48:05 -0700291 index += spd.nr_pages;
Jens Axboeeb207962006-04-27 11:05:22 +0200292
293 /*
294 * If find_get_pages_contig() returned fewer pages than we needed,
Fengguang Wu431a4822007-07-19 01:48:05 -0700295 * readahead/allocate the rest and fill in the holes.
Jens Axboeeb207962006-04-27 11:05:22 +0200296 */
Fengguang Wu431a4822007-07-19 01:48:05 -0700297 if (spd.nr_pages < nr_pages)
Rusty Russellcf914a72007-07-19 01:48:08 -0700298 page_cache_sync_readahead(mapping, &in->f_ra, in,
299 index, req_pages - spd.nr_pages);
Fengguang Wu431a4822007-07-19 01:48:05 -0700300
Jens Axboe932cc6d2007-06-21 13:10:21 +0200301 error = 0;
Jens Axboeeb207962006-04-27 11:05:22 +0200302 while (spd.nr_pages < nr_pages) {
303 /*
304 * Page could be there, find_get_pages_contig() breaks on
305 * the first hole.
306 */
307 page = find_get_page(mapping, index);
308 if (!page) {
Jens Axboee27dedd2006-05-01 19:59:54 +0200309 /*
Jens Axboeeb207962006-04-27 11:05:22 +0200310 * page didn't exist, allocate one.
311 */
312 page = page_cache_alloc_cold(mapping);
313 if (!page)
314 break;
315
316 error = add_to_page_cache_lru(page, mapping, index,
Nick Piggin2ae88142006-10-28 10:38:23 -0700317 GFP_KERNEL);
Jens Axboeeb207962006-04-27 11:05:22 +0200318 if (unlikely(error)) {
319 page_cache_release(page);
Jens Axboea0548872006-05-03 10:58:22 +0200320 if (error == -EEXIST)
321 continue;
Jens Axboeeb207962006-04-27 11:05:22 +0200322 break;
323 }
324 /*
325 * add_to_page_cache() locks the page, unlock it
326 * to avoid convoluting the logic below even more.
327 */
328 unlock_page(page);
329 }
330
331 pages[spd.nr_pages++] = page;
332 index++;
333 }
334
335 /*
336 * Now loop over the map and see if we need to start IO on any
337 * pages, fill in the partial map, etc.
338 */
339 index = *ppos >> PAGE_CACHE_SHIFT;
340 nr_pages = spd.nr_pages;
341 spd.nr_pages = 0;
342 for (page_nr = 0; page_nr < nr_pages; page_nr++) {
Jens Axboe82aa5d62006-04-20 13:05:48 +0200343 unsigned int this_len;
344
345 if (!len)
346 break;
347
348 /*
349 * this_len is the max we'll use from this page
350 */
Andrew Mortonba5f5d92006-04-25 15:33:34 +0200351 this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
Jens Axboeeb207962006-04-27 11:05:22 +0200352 page = pages[page_nr];
Jens Axboe7480a902006-04-11 13:52:47 +0200353
Fengguang Wua08a1662007-07-19 01:48:03 -0700354 if (PageReadahead(page))
Rusty Russellcf914a72007-07-19 01:48:08 -0700355 page_cache_async_readahead(mapping, &in->f_ra, in,
Fengguang Wud8983912007-07-19 01:48:06 -0700356 page, index, req_pages - page_nr);
Fengguang Wua08a1662007-07-19 01:48:03 -0700357
Jens Axboe7480a902006-04-11 13:52:47 +0200358 /*
359 * If the page isn't uptodate, we may need to start io on it
360 */
361 if (!PageUptodate(page)) {
Jens Axboec4f895c2006-04-19 15:56:12 +0200362 /*
363 * If in nonblock mode then dont block on waiting
364 * for an in-flight io page
365 */
Fengguang Wu9ae9d682007-05-08 08:44:36 +0200366 if (flags & SPLICE_F_NONBLOCK) {
367 if (TestSetPageLocked(page))
368 break;
369 } else
370 lock_page(page);
Jens Axboe7480a902006-04-11 13:52:47 +0200371
372 /*
373 * page was truncated, stop here. if this isn't the
374 * first page, we'll just complete what we already
375 * added
376 */
377 if (!page->mapping) {
378 unlock_page(page);
Jens Axboe7480a902006-04-11 13:52:47 +0200379 break;
380 }
381 /*
382 * page was already under io and is now done, great
383 */
384 if (PageUptodate(page)) {
385 unlock_page(page);
386 goto fill_it;
387 }
388
Jens Axboe7480a902006-04-11 13:52:47 +0200389 /*
390 * need to read in the page
391 */
392 error = mapping->a_ops->readpage(in, page);
Jens Axboe7480a902006-04-11 13:52:47 +0200393 if (unlikely(error)) {
Jens Axboeeb207962006-04-27 11:05:22 +0200394 /*
395 * We really should re-lookup the page here,
396 * but it complicates things a lot. Instead
397 * lets just do what we already stored, and
398 * we'll get it the next time we are called.
399 */
Jens Axboe7480a902006-04-11 13:52:47 +0200400 if (error == AOP_TRUNCATED_PAGE)
Jens Axboeeb207962006-04-27 11:05:22 +0200401 error = 0;
402
Jens Axboe7480a902006-04-11 13:52:47 +0200403 break;
404 }
Jens Axboe620a3242007-06-07 09:39:42 +0200405 }
406fill_it:
407 /*
408 * i_size must be checked after PageUptodate.
409 */
410 isize = i_size_read(mapping->host);
411 end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
412 if (unlikely(!isize || index > end_index))
413 break;
414
415 /*
416 * if this is the last page, see if we need to shrink
417 * the length and stop
418 */
419 if (end_index == index) {
420 unsigned int plen;
Jens Axboe91ad66e2006-04-19 15:55:10 +0200421
422 /*
Jens Axboe620a3242007-06-07 09:39:42 +0200423 * max good bytes in this page
Jens Axboe91ad66e2006-04-19 15:55:10 +0200424 */
Jens Axboe620a3242007-06-07 09:39:42 +0200425 plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
426 if (plen <= loff)
Jens Axboe91ad66e2006-04-19 15:55:10 +0200427 break;
Jens Axboe91ad66e2006-04-19 15:55:10 +0200428
429 /*
Jens Axboe620a3242007-06-07 09:39:42 +0200430 * force quit after adding this page
Jens Axboe91ad66e2006-04-19 15:55:10 +0200431 */
Jens Axboe620a3242007-06-07 09:39:42 +0200432 this_len = min(this_len, plen - loff);
433 len = this_len;
Jens Axboe7480a902006-04-11 13:52:47 +0200434 }
Jens Axboe620a3242007-06-07 09:39:42 +0200435
Jens Axboeeb207962006-04-27 11:05:22 +0200436 partial[page_nr].offset = loff;
437 partial[page_nr].len = this_len;
Jens Axboe82aa5d62006-04-20 13:05:48 +0200438 len -= this_len;
Jens Axboe91ad66e2006-04-19 15:55:10 +0200439 loff = 0;
Jens Axboeeb207962006-04-27 11:05:22 +0200440 spd.nr_pages++;
441 index++;
Jens Axboe5274f052006-03-30 15:15:30 +0200442 }
443
Jens Axboeeb207962006-04-27 11:05:22 +0200444 /*
Hugh Dickins475ecad2007-06-07 09:36:00 +0200445 * Release any pages at the end, if we quit early. 'page_nr' is how far
Jens Axboeeb207962006-04-27 11:05:22 +0200446 * we got, 'nr_pages' is how many pages are in the map.
447 */
448 while (page_nr < nr_pages)
449 page_cache_release(pages[page_nr++]);
Fengguang Wua08a1662007-07-19 01:48:03 -0700450 in->f_ra.prev_index = index;
Jens Axboeeb207962006-04-27 11:05:22 +0200451
Jens Axboe912d35f2006-04-26 10:59:21 +0200452 if (spd.nr_pages)
Jens Axboe00522fb2006-04-26 14:39:29 +0200453 return splice_to_pipe(pipe, &spd);
Jens Axboe5274f052006-03-30 15:15:30 +0200454
Jens Axboe7480a902006-04-11 13:52:47 +0200455 return error;
Jens Axboe5274f052006-03-30 15:15:30 +0200456}
457
Jens Axboe83f91352006-04-02 23:05:09 +0200458/**
459 * generic_file_splice_read - splice data from file to a pipe
460 * @in: file to splice from
Jens Axboe932cc6d2007-06-21 13:10:21 +0200461 * @ppos: position in @in
Jens Axboe83f91352006-04-02 23:05:09 +0200462 * @pipe: pipe to splice to
463 * @len: number of bytes to splice
464 * @flags: splice modifier flags
465 *
Jens Axboe932cc6d2007-06-21 13:10:21 +0200466 * Description:
467 * Will read pages from given file and fill them into a pipe. Can be
468 * used as long as the address_space operations for the source implements
469 * a readpage() hook.
470 *
Jens Axboe83f91352006-04-02 23:05:09 +0200471 */
Jens Axboecbb7e572006-04-11 14:57:50 +0200472ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
473 struct pipe_inode_info *pipe, size_t len,
474 unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200475{
476 ssize_t spliced;
477 int ret;
Jens Axboed366d3982007-06-01 14:54:11 +0200478 loff_t isize, left;
479
480 isize = i_size_read(in->f_mapping->host);
481 if (unlikely(*ppos >= isize))
482 return 0;
483
484 left = isize - *ppos;
485 if (unlikely(left < len))
486 len = left;
Jens Axboe5274f052006-03-30 15:15:30 +0200487
488 ret = 0;
489 spliced = 0;
Jens Axboe51a92c02007-07-13 14:11:43 +0200490 while (len && !spliced) {
Jens Axboecbb7e572006-04-11 14:57:50 +0200491 ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
Jens Axboe5274f052006-03-30 15:15:30 +0200492
Jens Axboec4f895c2006-04-19 15:56:12 +0200493 if (ret < 0)
Jens Axboe5274f052006-03-30 15:15:30 +0200494 break;
Jens Axboec4f895c2006-04-19 15:56:12 +0200495 else if (!ret) {
496 if (spliced)
497 break;
498 if (flags & SPLICE_F_NONBLOCK) {
499 ret = -EAGAIN;
500 break;
501 }
502 }
Jens Axboe5274f052006-03-30 15:15:30 +0200503
Jens Axboecbb7e572006-04-11 14:57:50 +0200504 *ppos += ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200505 len -= ret;
506 spliced += ret;
507 }
508
509 if (spliced)
510 return spliced;
511
512 return ret;
513}
514
Jens Axboe059a8f32006-04-02 23:06:05 +0200515EXPORT_SYMBOL(generic_file_splice_read);
516
Jens Axboe5274f052006-03-30 15:15:30 +0200517/*
Jens Axboe4f6f0bd2006-04-02 23:04:46 +0200518 * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
Jens Axboe016b6612006-04-25 15:42:00 +0200519 * using sendpage(). Return the number of bytes sent.
Jens Axboe5274f052006-03-30 15:15:30 +0200520 */
Jens Axboe76ad4d12006-05-03 10:41:33 +0200521static int pipe_to_sendpage(struct pipe_inode_info *pipe,
Jens Axboe5274f052006-03-30 15:15:30 +0200522 struct pipe_buffer *buf, struct splice_desc *sd)
523{
Jens Axboe6a14b902007-06-14 13:08:55 +0200524 struct file *file = sd->u.file;
Jens Axboe5274f052006-03-30 15:15:30 +0200525 loff_t pos = sd->pos;
Jens Axboef84d7512006-05-01 19:59:03 +0200526 int ret, more;
Jens Axboe5274f052006-03-30 15:15:30 +0200527
Jens Axboecac36bb2007-06-14 13:10:48 +0200528 ret = buf->ops->confirm(pipe, buf);
Jens Axboef84d7512006-05-01 19:59:03 +0200529 if (!ret) {
530 more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
Jens Axboe5274f052006-03-30 15:15:30 +0200531
Jens Axboef84d7512006-05-01 19:59:03 +0200532 ret = file->f_op->sendpage(file, buf->page, buf->offset,
533 sd->len, &pos, more);
534 }
Jens Axboe5274f052006-03-30 15:15:30 +0200535
Jens Axboe016b6612006-04-25 15:42:00 +0200536 return ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200537}
538
539/*
540 * This is a little more tricky than the file -> pipe splicing. There are
541 * basically three cases:
542 *
543 * - Destination page already exists in the address space and there
544 * are users of it. For that case we have no other option that
545 * copying the data. Tough luck.
546 * - Destination page already exists in the address space, but there
547 * are no users of it. Make sure it's uptodate, then drop it. Fall
548 * through to last case.
549 * - Destination page does not exist, we can add the pipe page to
550 * the page cache and avoid the copy.
551 *
Jens Axboe83f91352006-04-02 23:05:09 +0200552 * If asked to move pages to the output file (SPLICE_F_MOVE is set in
553 * sd->flags), we attempt to migrate pages from the pipe to the output
554 * file address space page cache. This is possible if no one else has
555 * the pipe page referenced outside of the pipe and page cache. If
556 * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
557 * a new page in the output file page cache and fill/dirty that.
Jens Axboe5274f052006-03-30 15:15:30 +0200558 */
Jens Axboe76ad4d12006-05-03 10:41:33 +0200559static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
Jens Axboe5274f052006-03-30 15:15:30 +0200560 struct splice_desc *sd)
561{
Jens Axboe6a14b902007-06-14 13:08:55 +0200562 struct file *file = sd->u.file;
Jens Axboe5274f052006-03-30 15:15:30 +0200563 struct address_space *mapping = file->f_mapping;
Jens Axboe016b6612006-04-25 15:42:00 +0200564 unsigned int offset, this_len;
Jens Axboe5274f052006-03-30 15:15:30 +0200565 struct page *page;
Jens Axboe5274f052006-03-30 15:15:30 +0200566 pgoff_t index;
Jens Axboe3e7ee3e2006-04-02 23:11:04 +0200567 int ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200568
569 /*
Jens Axboe49d0b212006-04-10 09:04:41 +0200570 * make sure the data in this buffer is uptodate
Jens Axboe5274f052006-03-30 15:15:30 +0200571 */
Jens Axboecac36bb2007-06-14 13:10:48 +0200572 ret = buf->ops->confirm(pipe, buf);
Jens Axboef84d7512006-05-01 19:59:03 +0200573 if (unlikely(ret))
574 return ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200575
576 index = sd->pos >> PAGE_CACHE_SHIFT;
577 offset = sd->pos & ~PAGE_CACHE_MASK;
578
Jens Axboe016b6612006-04-25 15:42:00 +0200579 this_len = sd->len;
580 if (this_len + offset > PAGE_CACHE_SIZE)
581 this_len = PAGE_CACHE_SIZE - offset;
582
Jens Axboe5abc97a2006-03-30 15:16:46 +0200583find_page:
Nick Piggin485ddb42007-03-27 08:55:08 +0200584 page = find_lock_page(mapping, index);
585 if (!page) {
586 ret = -ENOMEM;
587 page = page_cache_alloc_cold(mapping);
588 if (unlikely(!page))
589 goto out_ret;
Jens Axboe9e0267c2006-04-19 15:57:31 +0200590
Nick Piggin485ddb42007-03-27 08:55:08 +0200591 /*
592 * This will also lock the page
593 */
594 ret = add_to_page_cache_lru(page, mapping, index,
595 GFP_KERNEL);
596 if (unlikely(ret))
Jens Axboe6a860c92007-07-20 15:18:12 +0200597 goto out_release;
Nick Piggin485ddb42007-03-27 08:55:08 +0200598 }
599
Jens Axboe016b6612006-04-25 15:42:00 +0200600 ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
Jens Axboebfc4ee32006-05-03 10:35:10 +0200601 if (unlikely(ret)) {
602 loff_t isize = i_size_read(mapping->host);
603
604 if (ret != AOP_TRUNCATED_PAGE)
605 unlock_page(page);
Jens Axboe4f6f0bd2006-04-02 23:04:46 +0200606 page_cache_release(page);
Jens Axboebfc4ee32006-05-03 10:35:10 +0200607 if (ret == AOP_TRUNCATED_PAGE)
608 goto find_page;
609
610 /*
611 * prepare_write() may have instantiated a few blocks
612 * outside i_size. Trim these off again.
613 */
614 if (sd->pos + this_len > isize)
615 vmtruncate(mapping->host, isize);
616
Jens Axboee6e80f22006-10-11 10:03:09 +0200617 goto out_ret;
Jens Axboebfc4ee32006-05-03 10:35:10 +0200618 }
Jens Axboe5274f052006-03-30 15:15:30 +0200619
Jens Axboe0568b402006-05-01 19:50:48 +0200620 if (buf->page != page) {
Jens Axboef84d7512006-05-01 19:59:03 +0200621 /*
622 * Careful, ->map() uses KM_USER0!
623 */
Jens Axboe76ad4d12006-05-03 10:41:33 +0200624 char *src = buf->ops->map(pipe, buf, 1);
Jens Axboef84d7512006-05-01 19:59:03 +0200625 char *dst = kmap_atomic(page, KM_USER1);
Jens Axboe5abc97a2006-03-30 15:16:46 +0200626
Jens Axboe016b6612006-04-25 15:42:00 +0200627 memcpy(dst + offset, src + buf->offset, this_len);
Jens Axboe5abc97a2006-03-30 15:16:46 +0200628 flush_dcache_page(page);
Jens Axboef84d7512006-05-01 19:59:03 +0200629 kunmap_atomic(dst, KM_USER1);
Jens Axboe76ad4d12006-05-03 10:41:33 +0200630 buf->ops->unmap(pipe, buf, src);
Jens Axboe5abc97a2006-03-30 15:16:46 +0200631 }
Jens Axboe5274f052006-03-30 15:15:30 +0200632
Jens Axboe016b6612006-04-25 15:42:00 +0200633 ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
Dmitriy Monakhovd9993c32007-03-29 14:24:09 +0200634 if (ret) {
635 if (ret == AOP_TRUNCATED_PAGE) {
636 page_cache_release(page);
637 goto find_page;
638 }
639 if (ret < 0)
640 goto out;
Jens Axboe0568b402006-05-01 19:50:48 +0200641 /*
Dmitriy Monakhovd9993c32007-03-29 14:24:09 +0200642 * Partial write has happened, so 'ret' already initialized by
643 * number of bytes written, Where is nothing we have to do here.
Jens Axboe0568b402006-05-01 19:50:48 +0200644 */
Dmitriy Monakhovd9993c32007-03-29 14:24:09 +0200645 } else
Jens Axboe0568b402006-05-01 19:50:48 +0200646 ret = this_len;
Dmitriy Monakhovd9993c32007-03-29 14:24:09 +0200647 /*
648 * Return the number of bytes written and mark page as
649 * accessed, we are now done!
650 */
651 mark_page_accessed(page);
Jens Axboe5274f052006-03-30 15:15:30 +0200652out:
Jens Axboe9e0267c2006-04-19 15:57:31 +0200653 unlock_page(page);
Jens Axboe6a860c92007-07-20 15:18:12 +0200654out_release:
655 page_cache_release(page);
Jens Axboee6e80f22006-10-11 10:03:09 +0200656out_ret:
Jens Axboe5274f052006-03-30 15:15:30 +0200657 return ret;
658}
659
Jens Axboe932cc6d2007-06-21 13:10:21 +0200660/**
661 * __splice_from_pipe - splice data from a pipe to given actor
662 * @pipe: pipe to splice from
663 * @sd: information to @actor
664 * @actor: handler that splices the data
665 *
666 * Description:
667 * This function does little more than loop over the pipe and call
668 * @actor to do the actual moving of a single struct pipe_buffer to
669 * the desired destination. See pipe_to_file, pipe_to_sendpage, or
670 * pipe_to_user.
671 *
Jens Axboe83f91352006-04-02 23:05:09 +0200672 */
Jens Axboec66ab6f2007-06-12 21:17:17 +0200673ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
674 splice_actor *actor)
Jens Axboe5274f052006-03-30 15:15:30 +0200675{
Jens Axboe5274f052006-03-30 15:15:30 +0200676 int ret, do_wakeup, err;
Jens Axboe5274f052006-03-30 15:15:30 +0200677
678 ret = 0;
679 do_wakeup = 0;
680
Jens Axboe5274f052006-03-30 15:15:30 +0200681 for (;;) {
Jens Axboe6f767b02006-04-11 13:53:56 +0200682 if (pipe->nrbufs) {
683 struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
Eric Dumazetd4c3cca2006-12-13 00:34:04 -0800684 const struct pipe_buf_operations *ops = buf->ops;
Jens Axboe5274f052006-03-30 15:15:30 +0200685
Jens Axboec66ab6f2007-06-12 21:17:17 +0200686 sd->len = buf->len;
687 if (sd->len > sd->total_len)
688 sd->len = sd->total_len;
Jens Axboe5274f052006-03-30 15:15:30 +0200689
Jens Axboec66ab6f2007-06-12 21:17:17 +0200690 err = actor(pipe, buf, sd);
Jens Axboe016b6612006-04-25 15:42:00 +0200691 if (err <= 0) {
Jens Axboe5274f052006-03-30 15:15:30 +0200692 if (!ret && err != -ENODATA)
693 ret = err;
694
695 break;
696 }
697
Jens Axboe016b6612006-04-25 15:42:00 +0200698 ret += err;
699 buf->offset += err;
700 buf->len -= err;
701
Jens Axboec66ab6f2007-06-12 21:17:17 +0200702 sd->len -= err;
703 sd->pos += err;
704 sd->total_len -= err;
705 if (sd->len)
Jens Axboe016b6612006-04-25 15:42:00 +0200706 continue;
Ingo Molnar73d62d82006-04-11 13:57:21 +0200707
Jens Axboe5274f052006-03-30 15:15:30 +0200708 if (!buf->len) {
709 buf->ops = NULL;
Ingo Molnar3a326a22006-04-10 15:18:35 +0200710 ops->release(pipe, buf);
Jens Axboe6f767b02006-04-11 13:53:56 +0200711 pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1);
712 pipe->nrbufs--;
713 if (pipe->inode)
714 do_wakeup = 1;
Jens Axboe5274f052006-03-30 15:15:30 +0200715 }
716
Jens Axboec66ab6f2007-06-12 21:17:17 +0200717 if (!sd->total_len)
Jens Axboe5274f052006-03-30 15:15:30 +0200718 break;
719 }
720
Jens Axboe6f767b02006-04-11 13:53:56 +0200721 if (pipe->nrbufs)
Jens Axboe5274f052006-03-30 15:15:30 +0200722 continue;
Ingo Molnar3a326a22006-04-10 15:18:35 +0200723 if (!pipe->writers)
Jens Axboe5274f052006-03-30 15:15:30 +0200724 break;
Ingo Molnar3a326a22006-04-10 15:18:35 +0200725 if (!pipe->waiting_writers) {
Jens Axboe5274f052006-03-30 15:15:30 +0200726 if (ret)
727 break;
728 }
729
Jens Axboec66ab6f2007-06-12 21:17:17 +0200730 if (sd->flags & SPLICE_F_NONBLOCK) {
Linus Torvalds29e35092006-04-02 12:46:35 -0700731 if (!ret)
732 ret = -EAGAIN;
733 break;
734 }
735
Jens Axboe5274f052006-03-30 15:15:30 +0200736 if (signal_pending(current)) {
737 if (!ret)
738 ret = -ERESTARTSYS;
739 break;
740 }
741
742 if (do_wakeup) {
Jens Axboec0bd1f62006-04-10 09:03:32 +0200743 smp_mb();
Ingo Molnar3a326a22006-04-10 15:18:35 +0200744 if (waitqueue_active(&pipe->wait))
745 wake_up_interruptible_sync(&pipe->wait);
746 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
Jens Axboe5274f052006-03-30 15:15:30 +0200747 do_wakeup = 0;
748 }
749
Ingo Molnar3a326a22006-04-10 15:18:35 +0200750 pipe_wait(pipe);
Jens Axboe5274f052006-03-30 15:15:30 +0200751 }
752
Jens Axboe5274f052006-03-30 15:15:30 +0200753 if (do_wakeup) {
Jens Axboec0bd1f62006-04-10 09:03:32 +0200754 smp_mb();
Ingo Molnar3a326a22006-04-10 15:18:35 +0200755 if (waitqueue_active(&pipe->wait))
756 wake_up_interruptible(&pipe->wait);
757 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
Jens Axboe5274f052006-03-30 15:15:30 +0200758 }
759
Jens Axboe5274f052006-03-30 15:15:30 +0200760 return ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200761}
Mark Fasheh40bee442007-03-21 13:11:02 +0100762EXPORT_SYMBOL(__splice_from_pipe);
Jens Axboe5274f052006-03-30 15:15:30 +0200763
Jens Axboe932cc6d2007-06-21 13:10:21 +0200764/**
765 * splice_from_pipe - splice data from a pipe to a file
766 * @pipe: pipe to splice from
767 * @out: file to splice to
768 * @ppos: position in @out
769 * @len: how many bytes to splice
770 * @flags: splice modifier flags
771 * @actor: handler that splices the data
772 *
773 * Description:
774 * See __splice_from_pipe. This function locks the input and output inodes,
775 * otherwise it's identical to __splice_from_pipe().
776 *
777 */
Mark Fasheh6da61802006-10-17 18:43:07 +0200778ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
779 loff_t *ppos, size_t len, unsigned int flags,
780 splice_actor *actor)
781{
782 ssize_t ret;
783 struct inode *inode = out->f_mapping->host;
Jens Axboec66ab6f2007-06-12 21:17:17 +0200784 struct splice_desc sd = {
785 .total_len = len,
786 .flags = flags,
787 .pos = *ppos,
Jens Axboe6a14b902007-06-14 13:08:55 +0200788 .u.file = out,
Jens Axboec66ab6f2007-06-12 21:17:17 +0200789 };
Mark Fasheh6da61802006-10-17 18:43:07 +0200790
791 /*
792 * The actor worker might be calling ->prepare_write and
793 * ->commit_write. Most of the time, these expect i_mutex to
794 * be held. Since this may result in an ABBA deadlock with
795 * pipe->inode, we have to order lock acquiry here.
796 */
797 inode_double_lock(inode, pipe->inode);
Jens Axboec66ab6f2007-06-12 21:17:17 +0200798 ret = __splice_from_pipe(pipe, &sd, actor);
Mark Fasheh6da61802006-10-17 18:43:07 +0200799 inode_double_unlock(inode, pipe->inode);
800
801 return ret;
802}
803
804/**
805 * generic_file_splice_write_nolock - generic_file_splice_write without mutexes
806 * @pipe: pipe info
807 * @out: file to write to
Jens Axboe932cc6d2007-06-21 13:10:21 +0200808 * @ppos: position in @out
Mark Fasheh6da61802006-10-17 18:43:07 +0200809 * @len: number of bytes to splice
810 * @flags: splice modifier flags
811 *
Jens Axboe932cc6d2007-06-21 13:10:21 +0200812 * Description:
813 * Will either move or copy pages (determined by @flags options) from
814 * the given pipe inode to the given file. The caller is responsible
815 * for acquiring i_mutex on both inodes.
Mark Fasheh6da61802006-10-17 18:43:07 +0200816 *
817 */
818ssize_t
819generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
820 loff_t *ppos, size_t len, unsigned int flags)
821{
822 struct address_space *mapping = out->f_mapping;
823 struct inode *inode = mapping->host;
Jens Axboec66ab6f2007-06-12 21:17:17 +0200824 struct splice_desc sd = {
825 .total_len = len,
826 .flags = flags,
827 .pos = *ppos,
Jens Axboe6a14b902007-06-14 13:08:55 +0200828 .u.file = out,
Jens Axboec66ab6f2007-06-12 21:17:17 +0200829 };
Mark Fasheh6da61802006-10-17 18:43:07 +0200830 ssize_t ret;
831 int err;
832
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800833 err = remove_suid(out->f_path.dentry);
Jens Axboe8c34e2d2006-10-17 19:43:22 +0200834 if (unlikely(err))
835 return err;
836
Jens Axboec66ab6f2007-06-12 21:17:17 +0200837 ret = __splice_from_pipe(pipe, &sd, pipe_to_file);
Mark Fasheh6da61802006-10-17 18:43:07 +0200838 if (ret > 0) {
Jens Axboe17ee4f42007-06-15 13:10:37 +0200839 unsigned long nr_pages;
840
Mark Fasheh6da61802006-10-17 18:43:07 +0200841 *ppos += ret;
Jens Axboe17ee4f42007-06-15 13:10:37 +0200842 nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Mark Fasheh6da61802006-10-17 18:43:07 +0200843
844 /*
845 * If file or inode is SYNC and we actually wrote some data,
846 * sync it.
847 */
848 if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
849 err = generic_osync_inode(inode, mapping,
850 OSYNC_METADATA|OSYNC_DATA);
851
852 if (err)
853 ret = err;
854 }
Jens Axboe17ee4f42007-06-15 13:10:37 +0200855 balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
Mark Fasheh6da61802006-10-17 18:43:07 +0200856 }
857
858 return ret;
859}
860
861EXPORT_SYMBOL(generic_file_splice_write_nolock);
862
Jens Axboe83f91352006-04-02 23:05:09 +0200863/**
864 * generic_file_splice_write - splice data from a pipe to a file
Ingo Molnar3a326a22006-04-10 15:18:35 +0200865 * @pipe: pipe info
Jens Axboe83f91352006-04-02 23:05:09 +0200866 * @out: file to write to
Jens Axboe932cc6d2007-06-21 13:10:21 +0200867 * @ppos: position in @out
Jens Axboe83f91352006-04-02 23:05:09 +0200868 * @len: number of bytes to splice
869 * @flags: splice modifier flags
870 *
Jens Axboe932cc6d2007-06-21 13:10:21 +0200871 * Description:
872 * Will either move or copy pages (determined by @flags options) from
873 * the given pipe inode to the given file.
Jens Axboe83f91352006-04-02 23:05:09 +0200874 *
875 */
Ingo Molnar3a326a22006-04-10 15:18:35 +0200876ssize_t
877generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
Jens Axboecbb7e572006-04-11 14:57:50 +0200878 loff_t *ppos, size_t len, unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200879{
Jens Axboe4f6f0bd2006-04-02 23:04:46 +0200880 struct address_space *mapping = out->f_mapping;
Jens Axboe8c34e2d2006-10-17 19:43:22 +0200881 struct inode *inode = mapping->host;
Ingo Molnar3a326a22006-04-10 15:18:35 +0200882 ssize_t ret;
Jens Axboe8c34e2d2006-10-17 19:43:22 +0200883 int err;
884
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800885 err = should_remove_suid(out->f_path.dentry);
Jens Axboe8c34e2d2006-10-17 19:43:22 +0200886 if (unlikely(err)) {
887 mutex_lock(&inode->i_mutex);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800888 err = __remove_suid(out->f_path.dentry, err);
Jens Axboe8c34e2d2006-10-17 19:43:22 +0200889 mutex_unlock(&inode->i_mutex);
890 if (err)
891 return err;
892 }
Ingo Molnar3a326a22006-04-10 15:18:35 +0200893
Jens Axboe00522fb2006-04-26 14:39:29 +0200894 ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
Jens Axboea4514eb2006-04-19 15:57:05 +0200895 if (ret > 0) {
Jens Axboe17ee4f42007-06-15 13:10:37 +0200896 unsigned long nr_pages;
897
Jens Axboea4514eb2006-04-19 15:57:05 +0200898 *ppos += ret;
Jens Axboe17ee4f42007-06-15 13:10:37 +0200899 nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Jens Axboe4f6f0bd2006-04-02 23:04:46 +0200900
Jens Axboea4514eb2006-04-19 15:57:05 +0200901 /*
902 * If file or inode is SYNC and we actually wrote some data,
903 * sync it.
904 */
905 if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
Jens Axboea4514eb2006-04-19 15:57:05 +0200906 mutex_lock(&inode->i_mutex);
907 err = generic_osync_inode(inode, mapping,
908 OSYNC_METADATA|OSYNC_DATA);
909 mutex_unlock(&inode->i_mutex);
910
911 if (err)
912 ret = err;
913 }
Jens Axboe17ee4f42007-06-15 13:10:37 +0200914 balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
Jens Axboe4f6f0bd2006-04-02 23:04:46 +0200915 }
916
917 return ret;
Jens Axboe5274f052006-03-30 15:15:30 +0200918}
919
Jens Axboe059a8f32006-04-02 23:06:05 +0200920EXPORT_SYMBOL(generic_file_splice_write);
921
Jens Axboe83f91352006-04-02 23:05:09 +0200922/**
923 * generic_splice_sendpage - splice data from a pipe to a socket
Jens Axboe932cc6d2007-06-21 13:10:21 +0200924 * @pipe: pipe to splice from
Jens Axboe83f91352006-04-02 23:05:09 +0200925 * @out: socket to write to
Jens Axboe932cc6d2007-06-21 13:10:21 +0200926 * @ppos: position in @out
Jens Axboe83f91352006-04-02 23:05:09 +0200927 * @len: number of bytes to splice
928 * @flags: splice modifier flags
929 *
Jens Axboe932cc6d2007-06-21 13:10:21 +0200930 * Description:
931 * Will send @len bytes from the pipe to a network socket. No data copying
932 * is involved.
Jens Axboe83f91352006-04-02 23:05:09 +0200933 *
934 */
Ingo Molnar3a326a22006-04-10 15:18:35 +0200935ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
Jens Axboecbb7e572006-04-11 14:57:50 +0200936 loff_t *ppos, size_t len, unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200937{
Jens Axboe00522fb2006-04-26 14:39:29 +0200938 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
Jens Axboe5274f052006-03-30 15:15:30 +0200939}
940
Jens Axboe059a8f32006-04-02 23:06:05 +0200941EXPORT_SYMBOL(generic_splice_sendpage);
Jeff Garzika0f06782006-03-30 23:06:13 -0500942
Jens Axboe83f91352006-04-02 23:05:09 +0200943/*
944 * Attempt to initiate a splice from pipe to file.
945 */
Ingo Molnar3a326a22006-04-10 15:18:35 +0200946static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
Jens Axboecbb7e572006-04-11 14:57:50 +0200947 loff_t *ppos, size_t len, unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200948{
Jens Axboe5274f052006-03-30 15:15:30 +0200949 int ret;
950
Jens Axboe49570e92006-04-11 13:56:09 +0200951 if (unlikely(!out->f_op || !out->f_op->splice_write))
Jens Axboe5274f052006-03-30 15:15:30 +0200952 return -EINVAL;
953
Jens Axboe49570e92006-04-11 13:56:09 +0200954 if (unlikely(!(out->f_mode & FMODE_WRITE)))
Jens Axboe5274f052006-03-30 15:15:30 +0200955 return -EBADF;
956
Jens Axboecbb7e572006-04-11 14:57:50 +0200957 ret = rw_verify_area(WRITE, out, ppos, len);
Jens Axboe5274f052006-03-30 15:15:30 +0200958 if (unlikely(ret < 0))
959 return ret;
960
James Morris29ce2052007-07-13 11:44:32 +0200961 ret = security_file_permission(out, MAY_WRITE);
962 if (unlikely(ret < 0))
963 return ret;
964
Jens Axboecbb7e572006-04-11 14:57:50 +0200965 return out->f_op->splice_write(pipe, out, ppos, len, flags);
Jens Axboe5274f052006-03-30 15:15:30 +0200966}
967
Jens Axboe83f91352006-04-02 23:05:09 +0200968/*
969 * Attempt to initiate a splice from a file to a pipe.
970 */
Jens Axboecbb7e572006-04-11 14:57:50 +0200971static long do_splice_to(struct file *in, loff_t *ppos,
972 struct pipe_inode_info *pipe, size_t len,
973 unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +0200974{
Jens Axboe5274f052006-03-30 15:15:30 +0200975 int ret;
976
Jens Axboe49570e92006-04-11 13:56:09 +0200977 if (unlikely(!in->f_op || !in->f_op->splice_read))
Jens Axboe5274f052006-03-30 15:15:30 +0200978 return -EINVAL;
979
Jens Axboe49570e92006-04-11 13:56:09 +0200980 if (unlikely(!(in->f_mode & FMODE_READ)))
Jens Axboe5274f052006-03-30 15:15:30 +0200981 return -EBADF;
982
Jens Axboecbb7e572006-04-11 14:57:50 +0200983 ret = rw_verify_area(READ, in, ppos, len);
Jens Axboe5274f052006-03-30 15:15:30 +0200984 if (unlikely(ret < 0))
985 return ret;
986
James Morris29ce2052007-07-13 11:44:32 +0200987 ret = security_file_permission(in, MAY_READ);
988 if (unlikely(ret < 0))
989 return ret;
990
Jens Axboecbb7e572006-04-11 14:57:50 +0200991 return in->f_op->splice_read(in, ppos, pipe, len, flags);
Jens Axboe5274f052006-03-30 15:15:30 +0200992}
993
Jens Axboe932cc6d2007-06-21 13:10:21 +0200994/**
995 * splice_direct_to_actor - splices data directly between two non-pipes
996 * @in: file to splice from
997 * @sd: actor information on where to splice to
998 * @actor: handles the data splicing
999 *
1000 * Description:
1001 * This is a special case helper to splice directly between two
1002 * points, without requiring an explicit pipe. Internally an allocated
Randy Dunlap79685b82007-07-27 08:08:51 +02001003 * pipe is cached in the process, and reused during the lifetime of
Jens Axboe932cc6d2007-06-21 13:10:21 +02001004 * that process.
1005 *
Jens Axboec66ab6f2007-06-12 21:17:17 +02001006 */
1007ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
1008 splice_direct_actor *actor)
Jens Axboeb92ce552006-04-11 13:52:07 +02001009{
1010 struct pipe_inode_info *pipe;
1011 long ret, bytes;
1012 umode_t i_mode;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001013 size_t len;
1014 int i, flags;
Jens Axboeb92ce552006-04-11 13:52:07 +02001015
1016 /*
1017 * We require the input being a regular file, as we don't want to
1018 * randomly drop data for eg socket -> socket splicing. Use the
1019 * piped splicing for that!
1020 */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001021 i_mode = in->f_path.dentry->d_inode->i_mode;
Jens Axboeb92ce552006-04-11 13:52:07 +02001022 if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode)))
1023 return -EINVAL;
1024
1025 /*
1026 * neither in nor out is a pipe, setup an internal pipe attached to
1027 * 'out' and transfer the wanted data from 'in' to 'out' through that
1028 */
1029 pipe = current->splice_pipe;
Jens Axboe49570e92006-04-11 13:56:09 +02001030 if (unlikely(!pipe)) {
Jens Axboeb92ce552006-04-11 13:52:07 +02001031 pipe = alloc_pipe_info(NULL);
1032 if (!pipe)
1033 return -ENOMEM;
1034
1035 /*
1036 * We don't have an immediate reader, but we'll read the stuff
Jens Axboe00522fb2006-04-26 14:39:29 +02001037 * out of the pipe right after the splice_to_pipe(). So set
Jens Axboeb92ce552006-04-11 13:52:07 +02001038 * PIPE_READERS appropriately.
1039 */
1040 pipe->readers = 1;
1041
1042 current->splice_pipe = pipe;
1043 }
1044
1045 /*
Ingo Molnar73d62d82006-04-11 13:57:21 +02001046 * Do the splice.
Jens Axboeb92ce552006-04-11 13:52:07 +02001047 */
1048 ret = 0;
1049 bytes = 0;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001050 len = sd->total_len;
1051 flags = sd->flags;
1052
1053 /*
1054 * Don't block on output, we have to drain the direct pipe.
1055 */
1056 sd->flags &= ~SPLICE_F_NONBLOCK;
Jens Axboeb92ce552006-04-11 13:52:07 +02001057
1058 while (len) {
Jens Axboe51a92c02007-07-13 14:11:43 +02001059 size_t read_len;
Jens Axboebcd4f3a2007-07-16 14:41:49 +02001060 loff_t pos = sd->pos;
Jens Axboeb92ce552006-04-11 13:52:07 +02001061
Jens Axboebcd4f3a2007-07-16 14:41:49 +02001062 ret = do_splice_to(in, &pos, pipe, len, flags);
Jens Axboe51a92c02007-07-13 14:11:43 +02001063 if (unlikely(ret <= 0))
Jens Axboeb92ce552006-04-11 13:52:07 +02001064 goto out_release;
1065
1066 read_len = ret;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001067 sd->total_len = read_len;
Jens Axboeb92ce552006-04-11 13:52:07 +02001068
1069 /*
1070 * NOTE: nonblocking mode only applies to the input. We
1071 * must not do the output in nonblocking mode as then we
1072 * could get stuck data in the internal pipe:
1073 */
Jens Axboec66ab6f2007-06-12 21:17:17 +02001074 ret = actor(pipe, sd);
Jens Axboe51a92c02007-07-13 14:11:43 +02001075 if (unlikely(ret <= 0))
Jens Axboeb92ce552006-04-11 13:52:07 +02001076 goto out_release;
1077
1078 bytes += ret;
1079 len -= ret;
Jens Axboebcd4f3a2007-07-16 14:41:49 +02001080 sd->pos = pos;
Jens Axboeb92ce552006-04-11 13:52:07 +02001081
Jens Axboe51a92c02007-07-13 14:11:43 +02001082 if (ret < read_len)
1083 goto out_release;
Jens Axboeb92ce552006-04-11 13:52:07 +02001084 }
1085
1086 pipe->nrbufs = pipe->curbuf = 0;
Jens Axboeb92ce552006-04-11 13:52:07 +02001087 return bytes;
1088
1089out_release:
1090 /*
1091 * If we did an incomplete transfer we must release
1092 * the pipe buffers in question:
1093 */
1094 for (i = 0; i < PIPE_BUFFERS; i++) {
1095 struct pipe_buffer *buf = pipe->bufs + i;
1096
1097 if (buf->ops) {
1098 buf->ops->release(pipe, buf);
1099 buf->ops = NULL;
1100 }
1101 }
1102 pipe->nrbufs = pipe->curbuf = 0;
1103
1104 /*
1105 * If we transferred some data, return the number of bytes:
1106 */
1107 if (bytes > 0)
1108 return bytes;
1109
1110 return ret;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001111
1112}
1113EXPORT_SYMBOL(splice_direct_to_actor);
1114
1115static int direct_splice_actor(struct pipe_inode_info *pipe,
1116 struct splice_desc *sd)
1117{
Jens Axboe6a14b902007-06-14 13:08:55 +02001118 struct file *file = sd->u.file;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001119
1120 return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
1121}
1122
Jens Axboe932cc6d2007-06-21 13:10:21 +02001123/**
1124 * do_splice_direct - splices data directly between two files
1125 * @in: file to splice from
1126 * @ppos: input file offset
1127 * @out: file to splice to
1128 * @len: number of bytes to splice
1129 * @flags: splice modifier flags
1130 *
1131 * Description:
1132 * For use by do_sendfile(). splice can easily emulate sendfile, but
1133 * doing it in the application would incur an extra system call
1134 * (splice in + splice out, as compared to just sendfile()). So this helper
1135 * can splice directly through a process-private pipe.
1136 *
1137 */
Jens Axboec66ab6f2007-06-12 21:17:17 +02001138long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
1139 size_t len, unsigned int flags)
1140{
1141 struct splice_desc sd = {
1142 .len = len,
1143 .total_len = len,
1144 .flags = flags,
1145 .pos = *ppos,
Jens Axboe6a14b902007-06-14 13:08:55 +02001146 .u.file = out,
Jens Axboec66ab6f2007-06-12 21:17:17 +02001147 };
Jens Axboe51a92c02007-07-13 14:11:43 +02001148 long ret;
Jens Axboec66ab6f2007-06-12 21:17:17 +02001149
1150 ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
Jens Axboe51a92c02007-07-13 14:11:43 +02001151 if (ret > 0)
1152 *ppos += ret;
1153
Jens Axboec66ab6f2007-06-12 21:17:17 +02001154 return ret;
Jens Axboeb92ce552006-04-11 13:52:07 +02001155}
1156
Jens Axboe83f91352006-04-02 23:05:09 +02001157/*
Jens Axboeddac0d32006-11-04 12:49:32 +01001158 * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
1159 * location, so checking ->i_pipe is not enough to verify that this is a
1160 * pipe.
1161 */
1162static inline struct pipe_inode_info *pipe_info(struct inode *inode)
1163{
1164 if (S_ISFIFO(inode->i_mode))
1165 return inode->i_pipe;
1166
1167 return NULL;
1168}
1169
1170/*
Jens Axboe83f91352006-04-02 23:05:09 +02001171 * Determine where to splice to/from.
1172 */
Ingo Molnar529565d2006-04-10 15:18:58 +02001173static long do_splice(struct file *in, loff_t __user *off_in,
1174 struct file *out, loff_t __user *off_out,
1175 size_t len, unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +02001176{
Ingo Molnar3a326a22006-04-10 15:18:35 +02001177 struct pipe_inode_info *pipe;
Jens Axboecbb7e572006-04-11 14:57:50 +02001178 loff_t offset, *off;
Jens Axboea4514eb2006-04-19 15:57:05 +02001179 long ret;
Jens Axboe5274f052006-03-30 15:15:30 +02001180
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001181 pipe = pipe_info(in->f_path.dentry->d_inode);
Ingo Molnar529565d2006-04-10 15:18:58 +02001182 if (pipe) {
1183 if (off_in)
1184 return -ESPIPE;
Jens Axboeb92ce552006-04-11 13:52:07 +02001185 if (off_out) {
1186 if (out->f_op->llseek == no_llseek)
1187 return -EINVAL;
Jens Axboecbb7e572006-04-11 14:57:50 +02001188 if (copy_from_user(&offset, off_out, sizeof(loff_t)))
Jens Axboeb92ce552006-04-11 13:52:07 +02001189 return -EFAULT;
Jens Axboecbb7e572006-04-11 14:57:50 +02001190 off = &offset;
1191 } else
1192 off = &out->f_pos;
Ingo Molnar529565d2006-04-10 15:18:58 +02001193
Jens Axboea4514eb2006-04-19 15:57:05 +02001194 ret = do_splice_from(pipe, out, off, len, flags);
1195
1196 if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
1197 ret = -EFAULT;
1198
1199 return ret;
Ingo Molnar529565d2006-04-10 15:18:58 +02001200 }
Jens Axboe5274f052006-03-30 15:15:30 +02001201
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001202 pipe = pipe_info(out->f_path.dentry->d_inode);
Ingo Molnar529565d2006-04-10 15:18:58 +02001203 if (pipe) {
1204 if (off_out)
1205 return -ESPIPE;
Jens Axboeb92ce552006-04-11 13:52:07 +02001206 if (off_in) {
1207 if (in->f_op->llseek == no_llseek)
1208 return -EINVAL;
Jens Axboecbb7e572006-04-11 14:57:50 +02001209 if (copy_from_user(&offset, off_in, sizeof(loff_t)))
Jens Axboeb92ce552006-04-11 13:52:07 +02001210 return -EFAULT;
Jens Axboecbb7e572006-04-11 14:57:50 +02001211 off = &offset;
1212 } else
1213 off = &in->f_pos;
Ingo Molnar529565d2006-04-10 15:18:58 +02001214
Jens Axboea4514eb2006-04-19 15:57:05 +02001215 ret = do_splice_to(in, off, pipe, len, flags);
1216
1217 if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
1218 ret = -EFAULT;
1219
1220 return ret;
Ingo Molnar529565d2006-04-10 15:18:58 +02001221 }
Jens Axboe5274f052006-03-30 15:15:30 +02001222
1223 return -EINVAL;
1224}
1225
Jens Axboe912d35f2006-04-26 10:59:21 +02001226/*
1227 * Map an iov into an array of pages and offset/length tupples. With the
1228 * partial_page structure, we can map several non-contiguous ranges into
1229 * our ones pages[] map instead of splitting that operation into pieces.
1230 * Could easily be exported as a generic helper for other users, in which
1231 * case one would probably want to add a 'max_nr_pages' parameter as well.
1232 */
1233static int get_iovec_page_array(const struct iovec __user *iov,
1234 unsigned int nr_vecs, struct page **pages,
Jens Axboe7afa6fd2006-05-01 20:02:33 +02001235 struct partial_page *partial, int aligned)
Jens Axboe912d35f2006-04-26 10:59:21 +02001236{
1237 int buffers = 0, error = 0;
1238
1239 /*
1240 * It's ok to take the mmap_sem for reading, even
1241 * across a "get_user()".
1242 */
1243 down_read(&current->mm->mmap_sem);
1244
1245 while (nr_vecs) {
1246 unsigned long off, npages;
1247 void __user *base;
1248 size_t len;
1249 int i;
1250
1251 /*
1252 * Get user address base and length for this iovec.
1253 */
1254 error = get_user(base, &iov->iov_base);
1255 if (unlikely(error))
1256 break;
1257 error = get_user(len, &iov->iov_len);
1258 if (unlikely(error))
1259 break;
1260
1261 /*
1262 * Sanity check this iovec. 0 read succeeds.
1263 */
1264 if (unlikely(!len))
1265 break;
1266 error = -EFAULT;
1267 if (unlikely(!base))
1268 break;
1269
1270 /*
1271 * Get this base offset and number of pages, then map
1272 * in the user pages.
1273 */
1274 off = (unsigned long) base & ~PAGE_MASK;
Jens Axboe7afa6fd2006-05-01 20:02:33 +02001275
1276 /*
1277 * If asked for alignment, the offset must be zero and the
1278 * length a multiple of the PAGE_SIZE.
1279 */
1280 error = -EINVAL;
1281 if (aligned && (off || len & ~PAGE_MASK))
1282 break;
1283
Jens Axboe912d35f2006-04-26 10:59:21 +02001284 npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1285 if (npages > PIPE_BUFFERS - buffers)
1286 npages = PIPE_BUFFERS - buffers;
1287
1288 error = get_user_pages(current, current->mm,
1289 (unsigned long) base, npages, 0, 0,
1290 &pages[buffers], NULL);
1291
1292 if (unlikely(error <= 0))
1293 break;
1294
1295 /*
1296 * Fill this contiguous range into the partial page map.
1297 */
1298 for (i = 0; i < error; i++) {
Jens Axboe75914892006-05-02 12:57:18 +02001299 const int plen = min_t(size_t, len, PAGE_SIZE - off);
Jens Axboe912d35f2006-04-26 10:59:21 +02001300
1301 partial[buffers].offset = off;
1302 partial[buffers].len = plen;
1303
1304 off = 0;
1305 len -= plen;
1306 buffers++;
1307 }
1308
1309 /*
1310 * We didn't complete this iov, stop here since it probably
1311 * means we have to move some of this into a pipe to
1312 * be able to continue.
1313 */
1314 if (len)
1315 break;
1316
1317 /*
1318 * Don't continue if we mapped fewer pages than we asked for,
1319 * or if we mapped the max number of pages that we have
1320 * room for.
1321 */
1322 if (error < npages || buffers == PIPE_BUFFERS)
1323 break;
1324
1325 nr_vecs--;
1326 iov++;
1327 }
1328
1329 up_read(&current->mm->mmap_sem);
1330
1331 if (buffers)
1332 return buffers;
1333
1334 return error;
1335}
1336
Jens Axboe6a14b902007-06-14 13:08:55 +02001337static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
1338 struct splice_desc *sd)
1339{
1340 char *src;
1341 int ret;
1342
Jens Axboecac36bb2007-06-14 13:10:48 +02001343 ret = buf->ops->confirm(pipe, buf);
Jens Axboe6a14b902007-06-14 13:08:55 +02001344 if (unlikely(ret))
1345 return ret;
1346
1347 /*
1348 * See if we can use the atomic maps, by prefaulting in the
1349 * pages and doing an atomic copy
1350 */
1351 if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) {
1352 src = buf->ops->map(pipe, buf, 1);
1353 ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset,
1354 sd->len);
1355 buf->ops->unmap(pipe, buf, src);
1356 if (!ret) {
1357 ret = sd->len;
1358 goto out;
1359 }
1360 }
1361
1362 /*
1363 * No dice, use slow non-atomic map and copy
1364 */
1365 src = buf->ops->map(pipe, buf, 0);
1366
1367 ret = sd->len;
1368 if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len))
1369 ret = -EFAULT;
1370
1371out:
1372 if (ret > 0)
1373 sd->u.userptr += ret;
1374 buf->ops->unmap(pipe, buf, src);
1375 return ret;
1376}
1377
1378/*
1379 * For lack of a better implementation, implement vmsplice() to userspace
1380 * as a simple copy of the pipes pages to the user iov.
1381 */
1382static long vmsplice_to_user(struct file *file, const struct iovec __user *iov,
1383 unsigned long nr_segs, unsigned int flags)
1384{
1385 struct pipe_inode_info *pipe;
1386 struct splice_desc sd;
1387 ssize_t size;
1388 int error;
1389 long ret;
1390
1391 pipe = pipe_info(file->f_path.dentry->d_inode);
1392 if (!pipe)
1393 return -EBADF;
1394
1395 if (pipe->inode)
1396 mutex_lock(&pipe->inode->i_mutex);
1397
1398 error = ret = 0;
1399 while (nr_segs) {
1400 void __user *base;
1401 size_t len;
1402
1403 /*
1404 * Get user address base and length for this iovec.
1405 */
1406 error = get_user(base, &iov->iov_base);
1407 if (unlikely(error))
1408 break;
1409 error = get_user(len, &iov->iov_len);
1410 if (unlikely(error))
1411 break;
1412
1413 /*
1414 * Sanity check this iovec. 0 read succeeds.
1415 */
1416 if (unlikely(!len))
1417 break;
1418 if (unlikely(!base)) {
1419 error = -EFAULT;
1420 break;
1421 }
1422
1423 sd.len = 0;
1424 sd.total_len = len;
1425 sd.flags = flags;
1426 sd.u.userptr = base;
1427 sd.pos = 0;
1428
1429 size = __splice_from_pipe(pipe, &sd, pipe_to_user);
1430 if (size < 0) {
1431 if (!ret)
1432 ret = size;
1433
1434 break;
1435 }
1436
1437 ret += size;
1438
1439 if (size < len)
1440 break;
1441
1442 nr_segs--;
1443 iov++;
1444 }
1445
1446 if (pipe->inode)
1447 mutex_unlock(&pipe->inode->i_mutex);
1448
1449 if (!ret)
1450 ret = error;
1451
1452 return ret;
1453}
1454
Jens Axboe912d35f2006-04-26 10:59:21 +02001455/*
1456 * vmsplice splices a user address range into a pipe. It can be thought of
1457 * as splice-from-memory, where the regular splice is splice-from-file (or
1458 * to file). In both cases the output is a pipe, naturally.
Jens Axboe912d35f2006-04-26 10:59:21 +02001459 */
Jens Axboe6a14b902007-06-14 13:08:55 +02001460static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
1461 unsigned long nr_segs, unsigned int flags)
Jens Axboe912d35f2006-04-26 10:59:21 +02001462{
Jens Axboeddac0d32006-11-04 12:49:32 +01001463 struct pipe_inode_info *pipe;
Jens Axboe912d35f2006-04-26 10:59:21 +02001464 struct page *pages[PIPE_BUFFERS];
1465 struct partial_page partial[PIPE_BUFFERS];
1466 struct splice_pipe_desc spd = {
1467 .pages = pages,
1468 .partial = partial,
1469 .flags = flags,
1470 .ops = &user_page_pipe_buf_ops,
1471 };
1472
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001473 pipe = pipe_info(file->f_path.dentry->d_inode);
Jens Axboeddac0d32006-11-04 12:49:32 +01001474 if (!pipe)
Jens Axboe912d35f2006-04-26 10:59:21 +02001475 return -EBADF;
Jens Axboe912d35f2006-04-26 10:59:21 +02001476
Jens Axboe7afa6fd2006-05-01 20:02:33 +02001477 spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial,
1478 flags & SPLICE_F_GIFT);
Jens Axboe912d35f2006-04-26 10:59:21 +02001479 if (spd.nr_pages <= 0)
1480 return spd.nr_pages;
1481
Jens Axboe00522fb2006-04-26 14:39:29 +02001482 return splice_to_pipe(pipe, &spd);
Jens Axboe912d35f2006-04-26 10:59:21 +02001483}
1484
Jens Axboe6a14b902007-06-14 13:08:55 +02001485/*
1486 * Note that vmsplice only really supports true splicing _from_ user memory
1487 * to a pipe, not the other way around. Splicing from user memory is a simple
1488 * operation that can be supported without any funky alignment restrictions
1489 * or nasty vm tricks. We simply map in the user memory and fill them into
1490 * a pipe. The reverse isn't quite as easy, though. There are two possible
1491 * solutions for that:
1492 *
1493 * - memcpy() the data internally, at which point we might as well just
1494 * do a regular read() on the buffer anyway.
1495 * - Lots of nasty vm tricks, that are neither fast nor flexible (it
1496 * has restriction limitations on both ends of the pipe).
1497 *
1498 * Currently we punt and implement it as a normal copy, see pipe_to_user().
1499 *
1500 */
Jens Axboe912d35f2006-04-26 10:59:21 +02001501asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov,
1502 unsigned long nr_segs, unsigned int flags)
1503{
1504 struct file *file;
1505 long error;
1506 int fput;
1507
Jens Axboe6a14b902007-06-14 13:08:55 +02001508 if (unlikely(nr_segs > UIO_MAXIOV))
1509 return -EINVAL;
1510 else if (unlikely(!nr_segs))
1511 return 0;
1512
Jens Axboe912d35f2006-04-26 10:59:21 +02001513 error = -EBADF;
1514 file = fget_light(fd, &fput);
1515 if (file) {
1516 if (file->f_mode & FMODE_WRITE)
Jens Axboe6a14b902007-06-14 13:08:55 +02001517 error = vmsplice_to_pipe(file, iov, nr_segs, flags);
1518 else if (file->f_mode & FMODE_READ)
1519 error = vmsplice_to_user(file, iov, nr_segs, flags);
Jens Axboe912d35f2006-04-26 10:59:21 +02001520
1521 fput_light(file, fput);
1522 }
1523
1524 return error;
1525}
1526
Ingo Molnar529565d2006-04-10 15:18:58 +02001527asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
1528 int fd_out, loff_t __user *off_out,
1529 size_t len, unsigned int flags)
Jens Axboe5274f052006-03-30 15:15:30 +02001530{
1531 long error;
1532 struct file *in, *out;
1533 int fput_in, fput_out;
1534
1535 if (unlikely(!len))
1536 return 0;
1537
1538 error = -EBADF;
Ingo Molnar529565d2006-04-10 15:18:58 +02001539 in = fget_light(fd_in, &fput_in);
Jens Axboe5274f052006-03-30 15:15:30 +02001540 if (in) {
1541 if (in->f_mode & FMODE_READ) {
Ingo Molnar529565d2006-04-10 15:18:58 +02001542 out = fget_light(fd_out, &fput_out);
Jens Axboe5274f052006-03-30 15:15:30 +02001543 if (out) {
1544 if (out->f_mode & FMODE_WRITE)
Ingo Molnar529565d2006-04-10 15:18:58 +02001545 error = do_splice(in, off_in,
1546 out, off_out,
1547 len, flags);
Jens Axboe5274f052006-03-30 15:15:30 +02001548 fput_light(out, fput_out);
1549 }
1550 }
1551
1552 fput_light(in, fput_in);
1553 }
1554
1555 return error;
1556}
Jens Axboe70524492006-04-11 15:51:17 +02001557
1558/*
Jens Axboeaadd06e2006-07-10 11:00:01 +02001559 * Make sure there's data to read. Wait for input if we can, otherwise
1560 * return an appropriate error.
1561 */
1562static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
1563{
1564 int ret;
1565
1566 /*
1567 * Check ->nrbufs without the inode lock first. This function
1568 * is speculative anyways, so missing one is ok.
1569 */
1570 if (pipe->nrbufs)
1571 return 0;
1572
1573 ret = 0;
1574 mutex_lock(&pipe->inode->i_mutex);
1575
1576 while (!pipe->nrbufs) {
1577 if (signal_pending(current)) {
1578 ret = -ERESTARTSYS;
1579 break;
1580 }
1581 if (!pipe->writers)
1582 break;
1583 if (!pipe->waiting_writers) {
1584 if (flags & SPLICE_F_NONBLOCK) {
1585 ret = -EAGAIN;
1586 break;
1587 }
1588 }
1589 pipe_wait(pipe);
1590 }
1591
1592 mutex_unlock(&pipe->inode->i_mutex);
1593 return ret;
1594}
1595
1596/*
1597 * Make sure there's writeable room. Wait for room if we can, otherwise
1598 * return an appropriate error.
1599 */
1600static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
1601{
1602 int ret;
1603
1604 /*
1605 * Check ->nrbufs without the inode lock first. This function
1606 * is speculative anyways, so missing one is ok.
1607 */
1608 if (pipe->nrbufs < PIPE_BUFFERS)
1609 return 0;
1610
1611 ret = 0;
1612 mutex_lock(&pipe->inode->i_mutex);
1613
1614 while (pipe->nrbufs >= PIPE_BUFFERS) {
1615 if (!pipe->readers) {
1616 send_sig(SIGPIPE, current, 0);
1617 ret = -EPIPE;
1618 break;
1619 }
1620 if (flags & SPLICE_F_NONBLOCK) {
1621 ret = -EAGAIN;
1622 break;
1623 }
1624 if (signal_pending(current)) {
1625 ret = -ERESTARTSYS;
1626 break;
1627 }
1628 pipe->waiting_writers++;
1629 pipe_wait(pipe);
1630 pipe->waiting_writers--;
1631 }
1632
1633 mutex_unlock(&pipe->inode->i_mutex);
1634 return ret;
1635}
1636
1637/*
Jens Axboe70524492006-04-11 15:51:17 +02001638 * Link contents of ipipe to opipe.
1639 */
1640static int link_pipe(struct pipe_inode_info *ipipe,
1641 struct pipe_inode_info *opipe,
1642 size_t len, unsigned int flags)
1643{
1644 struct pipe_buffer *ibuf, *obuf;
Jens Axboeaadd06e2006-07-10 11:00:01 +02001645 int ret = 0, i = 0, nbuf;
Jens Axboe70524492006-04-11 15:51:17 +02001646
1647 /*
1648 * Potential ABBA deadlock, work around it by ordering lock
1649 * grabbing by inode address. Otherwise two different processes
1650 * could deadlock (one doing tee from A -> B, the other from B -> A).
1651 */
Mark Fasheh62752ee2006-10-17 10:31:38 +02001652 inode_double_lock(ipipe->inode, opipe->inode);
Jens Axboe70524492006-04-11 15:51:17 +02001653
Jens Axboeaadd06e2006-07-10 11:00:01 +02001654 do {
Jens Axboe70524492006-04-11 15:51:17 +02001655 if (!opipe->readers) {
1656 send_sig(SIGPIPE, current, 0);
1657 if (!ret)
1658 ret = -EPIPE;
1659 break;
1660 }
Jens Axboe70524492006-04-11 15:51:17 +02001661
1662 /*
Jens Axboeaadd06e2006-07-10 11:00:01 +02001663 * If we have iterated all input buffers or ran out of
1664 * output room, break.
Jens Axboe70524492006-04-11 15:51:17 +02001665 */
Jens Axboeaadd06e2006-07-10 11:00:01 +02001666 if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS)
Jens Axboe70524492006-04-11 15:51:17 +02001667 break;
Jens Axboeaadd06e2006-07-10 11:00:01 +02001668
1669 ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
1670 nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
1671
Jens Axboe2a272502006-04-19 15:56:40 +02001672 /*
Jens Axboeaadd06e2006-07-10 11:00:01 +02001673 * Get a reference to this pipe buffer,
1674 * so we can copy the contents over.
Jens Axboe2a272502006-04-19 15:56:40 +02001675 */
Jens Axboeaadd06e2006-07-10 11:00:01 +02001676 ibuf->ops->get(ipipe, ibuf);
Jens Axboe70524492006-04-11 15:51:17 +02001677
Jens Axboeaadd06e2006-07-10 11:00:01 +02001678 obuf = opipe->bufs + nbuf;
1679 *obuf = *ibuf;
Jens Axboe70524492006-04-11 15:51:17 +02001680
Jens Axboeaadd06e2006-07-10 11:00:01 +02001681 /*
1682 * Don't inherit the gift flag, we need to
1683 * prevent multiple steals of this page.
1684 */
1685 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1686
1687 if (obuf->len > len)
1688 obuf->len = len;
1689
1690 opipe->nrbufs++;
1691 ret += obuf->len;
1692 len -= obuf->len;
1693 i++;
1694 } while (len);
Jens Axboe70524492006-04-11 15:51:17 +02001695
Mark Fasheh62752ee2006-10-17 10:31:38 +02001696 inode_double_unlock(ipipe->inode, opipe->inode);
Jens Axboe70524492006-04-11 15:51:17 +02001697
Jens Axboeaadd06e2006-07-10 11:00:01 +02001698 /*
1699 * If we put data in the output pipe, wakeup any potential readers.
1700 */
1701 if (ret > 0) {
Jens Axboe70524492006-04-11 15:51:17 +02001702 smp_mb();
1703 if (waitqueue_active(&opipe->wait))
1704 wake_up_interruptible(&opipe->wait);
1705 kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
1706 }
1707
1708 return ret;
1709}
1710
1711/*
1712 * This is a tee(1) implementation that works on pipes. It doesn't copy
1713 * any data, it simply references the 'in' pages on the 'out' pipe.
1714 * The 'flags' used are the SPLICE_F_* variants, currently the only
1715 * applicable one is SPLICE_F_NONBLOCK.
1716 */
1717static long do_tee(struct file *in, struct file *out, size_t len,
1718 unsigned int flags)
1719{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001720 struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode);
1721 struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode);
Jens Axboeaadd06e2006-07-10 11:00:01 +02001722 int ret = -EINVAL;
Jens Axboe70524492006-04-11 15:51:17 +02001723
1724 /*
Jens Axboeaadd06e2006-07-10 11:00:01 +02001725 * Duplicate the contents of ipipe to opipe without actually
1726 * copying the data.
Jens Axboe70524492006-04-11 15:51:17 +02001727 */
Jens Axboeaadd06e2006-07-10 11:00:01 +02001728 if (ipipe && opipe && ipipe != opipe) {
1729 /*
1730 * Keep going, unless we encounter an error. The ipipe/opipe
1731 * ordering doesn't really matter.
1732 */
1733 ret = link_ipipe_prep(ipipe, flags);
1734 if (!ret) {
1735 ret = link_opipe_prep(opipe, flags);
1736 if (!ret) {
1737 ret = link_pipe(ipipe, opipe, len, flags);
1738 if (!ret && (flags & SPLICE_F_NONBLOCK))
1739 ret = -EAGAIN;
1740 }
1741 }
1742 }
Jens Axboe70524492006-04-11 15:51:17 +02001743
Jens Axboeaadd06e2006-07-10 11:00:01 +02001744 return ret;
Jens Axboe70524492006-04-11 15:51:17 +02001745}
1746
1747asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags)
1748{
1749 struct file *in;
1750 int error, fput_in;
1751
1752 if (unlikely(!len))
1753 return 0;
1754
1755 error = -EBADF;
1756 in = fget_light(fdin, &fput_in);
1757 if (in) {
1758 if (in->f_mode & FMODE_READ) {
1759 int fput_out;
1760 struct file *out = fget_light(fdout, &fput_out);
1761
1762 if (out) {
1763 if (out->f_mode & FMODE_WRITE)
1764 error = do_tee(in, out, len, flags);
1765 fput_light(out, fput_out);
1766 }
1767 }
1768 fput_light(in, fput_in);
1769 }
1770
1771 return error;
1772}