15274f052SJens Axboe /* 25274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 35274f052SJens Axboe * 45274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 55274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 65274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 75274f052SJens Axboe * 85274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 95274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 105274f052SJens Axboe * 115274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 12c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 13c2058e06SJens Axboe * fixing lots of bugs. 145274f052SJens Axboe * 15c2058e06SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de> 16c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 17c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 185274f052SJens Axboe * 195274f052SJens Axboe */ 205274f052SJens Axboe #include <linux/fs.h> 215274f052SJens Axboe #include <linux/file.h> 225274f052SJens Axboe #include <linux/pagemap.h> 235274f052SJens Axboe #include <linux/pipe_fs_i.h> 245274f052SJens Axboe #include <linux/mm_inline.h> 255abc97aaSJens Axboe #include <linux/swap.h> 264f6f0bd2SJens Axboe #include <linux/writeback.h> 274f6f0bd2SJens Axboe #include <linux/buffer_head.h> 28a0f06780SJeff Garzik #include <linux/module.h> 294f6f0bd2SJens Axboe #include <linux/syscalls.h> 30912d35f8SJens Axboe #include <linux/uio.h> 315274f052SJens Axboe 32912d35f8SJens Axboe struct partial_page { 33912d35f8SJens Axboe unsigned int offset; 34912d35f8SJens Axboe unsigned int len; 35912d35f8SJens Axboe }; 36912d35f8SJens Axboe 37912d35f8SJens Axboe /* 3800522fb4SJens Axboe * Passed to splice_to_pipe 39912d35f8SJens Axboe */ 40912d35f8SJens Axboe struct splice_pipe_desc { 41912d35f8SJens Axboe struct page **pages; /* page map */ 42912d35f8SJens Axboe struct partial_page *partial; /* pages[] may not be contig */ 43912d35f8SJens Axboe int nr_pages; /* number of pages in map */ 44912d35f8SJens Axboe unsigned int flags; /* splice flags */ 45912d35f8SJens Axboe struct pipe_buf_operations *ops;/* ops associated with output pipe */ 46912d35f8SJens Axboe }; 47912d35f8SJens Axboe 4883f9135bSJens Axboe /* 4983f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 5083f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 5183f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 5283f9135bSJens Axboe * attempt to reuse this page for another destination. 5383f9135bSJens Axboe */ 545abc97aaSJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, 555abc97aaSJens Axboe struct pipe_buffer *buf) 565abc97aaSJens Axboe { 575abc97aaSJens Axboe struct page *page = buf->page; 584f6f0bd2SJens Axboe struct address_space *mapping = page_mapping(page); 595abc97aaSJens Axboe 609e0267c2SJens Axboe lock_page(page); 619e0267c2SJens Axboe 625abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 635abc97aaSJens Axboe 64ad8d6f0aSJens Axboe /* 65ad8d6f0aSJens Axboe * At least for ext2 with nobh option, we need to wait on writeback 66ad8d6f0aSJens Axboe * completing on this page, since we'll remove it from the pagecache. 67ad8d6f0aSJens Axboe * Otherwise truncate wont wait on the page, allowing the disk 68ad8d6f0aSJens Axboe * blocks to be reused by someone else before we actually wrote our 69ad8d6f0aSJens Axboe * data to them. fs corruption ensues. 70ad8d6f0aSJens Axboe */ 71ad8d6f0aSJens Axboe wait_on_page_writeback(page); 72ad8d6f0aSJens Axboe 734f6f0bd2SJens Axboe if (PagePrivate(page)) 744f6f0bd2SJens Axboe try_to_release_page(page, mapping_gfp_mask(mapping)); 754f6f0bd2SJens Axboe 769e0267c2SJens Axboe if (!remove_mapping(mapping, page)) { 779e0267c2SJens Axboe unlock_page(page); 785abc97aaSJens Axboe return 1; 799e0267c2SJens Axboe } 805abc97aaSJens Axboe 813e7ee3e7SJens Axboe buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; 825abc97aaSJens Axboe return 0; 835abc97aaSJens Axboe } 845abc97aaSJens Axboe 855274f052SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *info, 865274f052SJens Axboe struct pipe_buffer *buf) 875274f052SJens Axboe { 885274f052SJens Axboe page_cache_release(buf->page); 895274f052SJens Axboe buf->page = NULL; 903e7ee3e7SJens Axboe buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); 915274f052SJens Axboe } 925274f052SJens Axboe 935274f052SJens Axboe static void *page_cache_pipe_buf_map(struct file *file, 945274f052SJens Axboe struct pipe_inode_info *info, 955274f052SJens Axboe struct pipe_buffer *buf) 965274f052SJens Axboe { 975274f052SJens Axboe struct page *page = buf->page; 9849d0b21bSJens Axboe int err; 995274f052SJens Axboe 1005274f052SJens Axboe if (!PageUptodate(page)) { 10149d0b21bSJens Axboe lock_page(page); 1025274f052SJens Axboe 10349d0b21bSJens Axboe /* 10449d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10573d62d83SIngo Molnar * splice, if this is the first page. 10649d0b21bSJens Axboe */ 1075274f052SJens Axboe if (!page->mapping) { 10849d0b21bSJens Axboe err = -ENODATA; 10949d0b21bSJens Axboe goto error; 1105274f052SJens Axboe } 1115274f052SJens Axboe 11249d0b21bSJens Axboe /* 11373d62d83SIngo Molnar * Uh oh, read-error from disk. 11449d0b21bSJens Axboe */ 11549d0b21bSJens Axboe if (!PageUptodate(page)) { 11649d0b21bSJens Axboe err = -EIO; 11749d0b21bSJens Axboe goto error; 11849d0b21bSJens Axboe } 11949d0b21bSJens Axboe 12049d0b21bSJens Axboe /* 12173d62d83SIngo Molnar * Page is ok afterall, fall through to mapping. 12249d0b21bSJens Axboe */ 12349d0b21bSJens Axboe unlock_page(page); 12449d0b21bSJens Axboe } 12549d0b21bSJens Axboe 12649d0b21bSJens Axboe return kmap(page); 12749d0b21bSJens Axboe error: 12849d0b21bSJens Axboe unlock_page(page); 12949d0b21bSJens Axboe return ERR_PTR(err); 1305274f052SJens Axboe } 1315274f052SJens Axboe 1325274f052SJens Axboe static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, 1335274f052SJens Axboe struct pipe_buffer *buf) 1345274f052SJens Axboe { 1355274f052SJens Axboe kunmap(buf->page); 1365274f052SJens Axboe } 1375274f052SJens Axboe 138912d35f8SJens Axboe static void *user_page_pipe_buf_map(struct file *file, 139912d35f8SJens Axboe struct pipe_inode_info *pipe, 140912d35f8SJens Axboe struct pipe_buffer *buf) 141912d35f8SJens Axboe { 142912d35f8SJens Axboe return kmap(buf->page); 143912d35f8SJens Axboe } 144912d35f8SJens Axboe 145912d35f8SJens Axboe static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe, 146912d35f8SJens Axboe struct pipe_buffer *buf) 147912d35f8SJens Axboe { 148912d35f8SJens Axboe kunmap(buf->page); 149912d35f8SJens Axboe } 150912d35f8SJens Axboe 15170524490SJens Axboe static void page_cache_pipe_buf_get(struct pipe_inode_info *info, 15270524490SJens Axboe struct pipe_buffer *buf) 15370524490SJens Axboe { 15470524490SJens Axboe page_cache_get(buf->page); 15570524490SJens Axboe } 15670524490SJens Axboe 1575274f052SJens Axboe static struct pipe_buf_operations page_cache_pipe_buf_ops = { 1585274f052SJens Axboe .can_merge = 0, 1595274f052SJens Axboe .map = page_cache_pipe_buf_map, 1605274f052SJens Axboe .unmap = page_cache_pipe_buf_unmap, 1615274f052SJens Axboe .release = page_cache_pipe_buf_release, 1625abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 16370524490SJens Axboe .get = page_cache_pipe_buf_get, 1645274f052SJens Axboe }; 1655274f052SJens Axboe 166912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 167912d35f8SJens Axboe struct pipe_buffer *buf) 168912d35f8SJens Axboe { 169912d35f8SJens Axboe return 1; 170912d35f8SJens Axboe } 171912d35f8SJens Axboe 172912d35f8SJens Axboe static struct pipe_buf_operations user_page_pipe_buf_ops = { 173912d35f8SJens Axboe .can_merge = 0, 174912d35f8SJens Axboe .map = user_page_pipe_buf_map, 175912d35f8SJens Axboe .unmap = user_page_pipe_buf_unmap, 176912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 177912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 178912d35f8SJens Axboe .get = page_cache_pipe_buf_get, 179912d35f8SJens Axboe }; 180912d35f8SJens Axboe 18183f9135bSJens Axboe /* 18283f9135bSJens Axboe * Pipe output worker. This sets up our pipe format with the page cache 18383f9135bSJens Axboe * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). 18483f9135bSJens Axboe */ 18500522fb4SJens Axboe static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 186912d35f8SJens Axboe struct splice_pipe_desc *spd) 1875274f052SJens Axboe { 188912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1895274f052SJens Axboe 1905274f052SJens Axboe ret = 0; 1915274f052SJens Axboe do_wakeup = 0; 192912d35f8SJens Axboe page_nr = 0; 1935274f052SJens Axboe 1943a326a2cSIngo Molnar if (pipe->inode) 1953a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1965274f052SJens Axboe 1975274f052SJens Axboe for (;;) { 1983a326a2cSIngo Molnar if (!pipe->readers) { 1995274f052SJens Axboe send_sig(SIGPIPE, current, 0); 2005274f052SJens Axboe if (!ret) 2015274f052SJens Axboe ret = -EPIPE; 2025274f052SJens Axboe break; 2035274f052SJens Axboe } 2045274f052SJens Axboe 2056f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 2066f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 2073a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 2085274f052SJens Axboe 209912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 210912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 211912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 212912d35f8SJens Axboe buf->ops = spd->ops; 2136f767b04SJens Axboe pipe->nrbufs++; 214912d35f8SJens Axboe page_nr++; 215912d35f8SJens Axboe ret += buf->len; 216912d35f8SJens Axboe 2176f767b04SJens Axboe if (pipe->inode) 2185274f052SJens Axboe do_wakeup = 1; 2195274f052SJens Axboe 220912d35f8SJens Axboe if (!--spd->nr_pages) 2215274f052SJens Axboe break; 2226f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2235274f052SJens Axboe continue; 2245274f052SJens Axboe 2255274f052SJens Axboe break; 2265274f052SJens Axboe } 2275274f052SJens Axboe 228912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22929e35094SLinus Torvalds if (!ret) 23029e35094SLinus Torvalds ret = -EAGAIN; 23129e35094SLinus Torvalds break; 23229e35094SLinus Torvalds } 23329e35094SLinus Torvalds 2345274f052SJens Axboe if (signal_pending(current)) { 2355274f052SJens Axboe if (!ret) 2365274f052SJens Axboe ret = -ERESTARTSYS; 2375274f052SJens Axboe break; 2385274f052SJens Axboe } 2395274f052SJens Axboe 2405274f052SJens Axboe if (do_wakeup) { 241c0bd1f65SJens Axboe smp_mb(); 2423a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2433a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2443a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2455274f052SJens Axboe do_wakeup = 0; 2465274f052SJens Axboe } 2475274f052SJens Axboe 2483a326a2cSIngo Molnar pipe->waiting_writers++; 2493a326a2cSIngo Molnar pipe_wait(pipe); 2503a326a2cSIngo Molnar pipe->waiting_writers--; 2515274f052SJens Axboe } 2525274f052SJens Axboe 2533a326a2cSIngo Molnar if (pipe->inode) 2543a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2555274f052SJens Axboe 2565274f052SJens Axboe if (do_wakeup) { 257c0bd1f65SJens Axboe smp_mb(); 2583a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2593a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2603a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2615274f052SJens Axboe } 2625274f052SJens Axboe 263912d35f8SJens Axboe while (page_nr < spd->nr_pages) 264912d35f8SJens Axboe page_cache_release(spd->pages[page_nr++]); 2655274f052SJens Axboe 2665274f052SJens Axboe return ret; 2675274f052SJens Axboe } 2685274f052SJens Axboe 2693a326a2cSIngo Molnar static int 270cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 271cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 272cbb7e577SJens Axboe unsigned int flags) 2735274f052SJens Axboe { 2745274f052SJens Axboe struct address_space *mapping = in->f_mapping; 275912d35f8SJens Axboe unsigned int loff, nr_pages; 27616c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 277912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2785274f052SJens Axboe struct page *page; 27991ad66efSJens Axboe pgoff_t index, end_index; 28091ad66efSJens Axboe loff_t isize; 281912d35f8SJens Axboe size_t total_len; 282eb20796bSJens Axboe int error, page_nr; 283912d35f8SJens Axboe struct splice_pipe_desc spd = { 284912d35f8SJens Axboe .pages = pages, 285912d35f8SJens Axboe .partial = partial, 286912d35f8SJens Axboe .flags = flags, 287912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 288912d35f8SJens Axboe }; 2895274f052SJens Axboe 290cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 291912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 292912d35f8SJens Axboe nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2935274f052SJens Axboe 2945274f052SJens Axboe if (nr_pages > PIPE_BUFFERS) 2955274f052SJens Axboe nr_pages = PIPE_BUFFERS; 2965274f052SJens Axboe 2975274f052SJens Axboe /* 29873d62d83SIngo Molnar * Initiate read-ahead on this page range. however, don't call into 2990b749ce3SJens Axboe * read-ahead if this is a non-zero offset (we are likely doing small 3000b749ce3SJens Axboe * chunk splice and the page is already there) for a single page. 3015274f052SJens Axboe */ 302eb645a24SJens Axboe if (!loff || nr_pages > 1) 303eb645a24SJens Axboe page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); 3045274f052SJens Axboe 3055274f052SJens Axboe /* 30673d62d83SIngo Molnar * Now fill in the holes: 3075274f052SJens Axboe */ 3087480a904SJens Axboe error = 0; 309912d35f8SJens Axboe total_len = 0; 31082aa5d61SJens Axboe 31182aa5d61SJens Axboe /* 312eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 31382aa5d61SJens Axboe */ 314eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 315eb20796bSJens Axboe 3165274f052SJens Axboe /* 317eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 318eb20796bSJens Axboe * allocate the rest. 319eb20796bSJens Axboe */ 320eb20796bSJens Axboe index += spd.nr_pages; 321eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 322eb20796bSJens Axboe /* 323eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 324eb20796bSJens Axboe * the first hole. 3255274f052SJens Axboe */ 3267480a904SJens Axboe page = find_get_page(mapping, index); 3277480a904SJens Axboe if (!page) { 3287480a904SJens Axboe /* 329eb20796bSJens Axboe * page didn't exist, allocate one. 3307480a904SJens Axboe */ 3317480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3325274f052SJens Axboe if (!page) 3335274f052SJens Axboe break; 3345274f052SJens Axboe 3357480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3367480a904SJens Axboe mapping_gfp_mask(mapping)); 3375274f052SJens Axboe if (unlikely(error)) { 3385274f052SJens Axboe page_cache_release(page); 3395274f052SJens Axboe break; 3405274f052SJens Axboe } 341eb20796bSJens Axboe /* 342eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 343eb20796bSJens Axboe * to avoid convoluting the logic below even more. 344eb20796bSJens Axboe */ 345eb20796bSJens Axboe unlock_page(page); 3465274f052SJens Axboe } 3477480a904SJens Axboe 348eb20796bSJens Axboe pages[spd.nr_pages++] = page; 349eb20796bSJens Axboe index++; 350eb20796bSJens Axboe } 351eb20796bSJens Axboe 352eb20796bSJens Axboe /* 353eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 354eb20796bSJens Axboe * pages, fill in the partial map, etc. 355eb20796bSJens Axboe */ 356eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 357eb20796bSJens Axboe nr_pages = spd.nr_pages; 358eb20796bSJens Axboe spd.nr_pages = 0; 359eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 360eb20796bSJens Axboe unsigned int this_len; 361eb20796bSJens Axboe 362eb20796bSJens Axboe if (!len) 363eb20796bSJens Axboe break; 364eb20796bSJens Axboe 365eb20796bSJens Axboe /* 366eb20796bSJens Axboe * this_len is the max we'll use from this page 367eb20796bSJens Axboe */ 368eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 369eb20796bSJens Axboe page = pages[page_nr]; 370eb20796bSJens Axboe 3717480a904SJens Axboe /* 3727480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3737480a904SJens Axboe */ 3747480a904SJens Axboe if (!PageUptodate(page)) { 375c4f895cbSJens Axboe /* 376c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 377c4f895cbSJens Axboe * for an in-flight io page 378c4f895cbSJens Axboe */ 379c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) 380c4f895cbSJens Axboe break; 381c4f895cbSJens Axboe 3827480a904SJens Axboe lock_page(page); 3837480a904SJens Axboe 3847480a904SJens Axboe /* 3857480a904SJens Axboe * page was truncated, stop here. if this isn't the 3867480a904SJens Axboe * first page, we'll just complete what we already 3877480a904SJens Axboe * added 3887480a904SJens Axboe */ 3897480a904SJens Axboe if (!page->mapping) { 3907480a904SJens Axboe unlock_page(page); 3917480a904SJens Axboe break; 3927480a904SJens Axboe } 3937480a904SJens Axboe /* 3947480a904SJens Axboe * page was already under io and is now done, great 3957480a904SJens Axboe */ 3967480a904SJens Axboe if (PageUptodate(page)) { 3977480a904SJens Axboe unlock_page(page); 3987480a904SJens Axboe goto fill_it; 3997480a904SJens Axboe } 4007480a904SJens Axboe 4017480a904SJens Axboe /* 4027480a904SJens Axboe * need to read in the page 4037480a904SJens Axboe */ 4047480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4057480a904SJens Axboe if (unlikely(error)) { 406eb20796bSJens Axboe /* 407eb20796bSJens Axboe * We really should re-lookup the page here, 408eb20796bSJens Axboe * but it complicates things a lot. Instead 409eb20796bSJens Axboe * lets just do what we already stored, and 410eb20796bSJens Axboe * we'll get it the next time we are called. 411eb20796bSJens Axboe */ 4127480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 413eb20796bSJens Axboe error = 0; 414eb20796bSJens Axboe 4157480a904SJens Axboe break; 4167480a904SJens Axboe } 41791ad66efSJens Axboe 41891ad66efSJens Axboe /* 41991ad66efSJens Axboe * i_size must be checked after ->readpage(). 42091ad66efSJens Axboe */ 42191ad66efSJens Axboe isize = i_size_read(mapping->host); 42291ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 423eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 42491ad66efSJens Axboe break; 42591ad66efSJens Axboe 42691ad66efSJens Axboe /* 42791ad66efSJens Axboe * if this is the last page, see if we need to shrink 42891ad66efSJens Axboe * the length and stop 42991ad66efSJens Axboe */ 43091ad66efSJens Axboe if (end_index == index) { 43191ad66efSJens Axboe loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); 432eb20796bSJens Axboe if (total_len + loff > isize) 43391ad66efSJens Axboe break; 43491ad66efSJens Axboe /* 43591ad66efSJens Axboe * force quit after adding this page 43691ad66efSJens Axboe */ 437eb20796bSJens Axboe len = this_len; 43882aa5d61SJens Axboe this_len = min(this_len, loff); 439912d35f8SJens Axboe loff = 0; 44091ad66efSJens Axboe } 4417480a904SJens Axboe } 4427480a904SJens Axboe fill_it: 443eb20796bSJens Axboe partial[page_nr].offset = loff; 444eb20796bSJens Axboe partial[page_nr].len = this_len; 44582aa5d61SJens Axboe len -= this_len; 446912d35f8SJens Axboe total_len += this_len; 44791ad66efSJens Axboe loff = 0; 448eb20796bSJens Axboe spd.nr_pages++; 449eb20796bSJens Axboe index++; 4505274f052SJens Axboe } 4515274f052SJens Axboe 452eb20796bSJens Axboe /* 453eb20796bSJens Axboe * Release any pages at the end, if we quit early. 'i' is how far 454eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 455eb20796bSJens Axboe */ 456eb20796bSJens Axboe while (page_nr < nr_pages) 457eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 458eb20796bSJens Axboe 459912d35f8SJens Axboe if (spd.nr_pages) 46000522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 46116c523ddSJens Axboe 4627480a904SJens Axboe return error; 4635274f052SJens Axboe } 4645274f052SJens Axboe 46583f9135bSJens Axboe /** 46683f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46783f9135bSJens Axboe * @in: file to splice from 46883f9135bSJens Axboe * @pipe: pipe to splice to 46983f9135bSJens Axboe * @len: number of bytes to splice 47083f9135bSJens Axboe * @flags: splice modifier flags 47183f9135bSJens Axboe * 47283f9135bSJens Axboe * Will read pages from given file and fill them into a pipe. 47383f9135bSJens Axboe */ 474cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 475cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 476cbb7e577SJens Axboe unsigned int flags) 4775274f052SJens Axboe { 4785274f052SJens Axboe ssize_t spliced; 4795274f052SJens Axboe int ret; 4805274f052SJens Axboe 4815274f052SJens Axboe ret = 0; 4825274f052SJens Axboe spliced = 0; 4833a326a2cSIngo Molnar 4845274f052SJens Axboe while (len) { 485cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4865274f052SJens Axboe 487c4f895cbSJens Axboe if (ret < 0) 4885274f052SJens Axboe break; 489c4f895cbSJens Axboe else if (!ret) { 490c4f895cbSJens Axboe if (spliced) 491c4f895cbSJens Axboe break; 492c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 493c4f895cbSJens Axboe ret = -EAGAIN; 494c4f895cbSJens Axboe break; 495c4f895cbSJens Axboe } 496c4f895cbSJens Axboe } 4975274f052SJens Axboe 498cbb7e577SJens Axboe *ppos += ret; 4995274f052SJens Axboe len -= ret; 5005274f052SJens Axboe spliced += ret; 5015274f052SJens Axboe } 5025274f052SJens Axboe 5035274f052SJens Axboe if (spliced) 5045274f052SJens Axboe return spliced; 5055274f052SJens Axboe 5065274f052SJens Axboe return ret; 5075274f052SJens Axboe } 5085274f052SJens Axboe 509059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 510059a8f37SJens Axboe 5115274f052SJens Axboe /* 5124f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 513016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5145274f052SJens Axboe */ 5155274f052SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *info, 5165274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5175274f052SJens Axboe { 5185274f052SJens Axboe struct file *file = sd->file; 5195274f052SJens Axboe loff_t pos = sd->pos; 5205274f052SJens Axboe ssize_t ret; 5215274f052SJens Axboe void *ptr; 522b2b39fa4SJens Axboe int more; 5235274f052SJens Axboe 5245274f052SJens Axboe /* 52573d62d83SIngo Molnar * Sub-optimal, but we are limited by the pipe ->map. We don't 5265274f052SJens Axboe * need a kmap'ed buffer here, we just want to make sure we 5275274f052SJens Axboe * have the page pinned if the pipe page originates from the 52873d62d83SIngo Molnar * page cache. 5295274f052SJens Axboe */ 5305274f052SJens Axboe ptr = buf->ops->map(file, info, buf); 5315274f052SJens Axboe if (IS_ERR(ptr)) 5325274f052SJens Axboe return PTR_ERR(ptr); 5335274f052SJens Axboe 534b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5355274f052SJens Axboe 536016b661eSJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len, 537016b661eSJens Axboe &pos, more); 5385274f052SJens Axboe 5395274f052SJens Axboe buf->ops->unmap(info, buf); 540016b661eSJens Axboe return ret; 5415274f052SJens Axboe } 5425274f052SJens Axboe 5435274f052SJens Axboe /* 5445274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5455274f052SJens Axboe * basically three cases: 5465274f052SJens Axboe * 5475274f052SJens Axboe * - Destination page already exists in the address space and there 5485274f052SJens Axboe * are users of it. For that case we have no other option that 5495274f052SJens Axboe * copying the data. Tough luck. 5505274f052SJens Axboe * - Destination page already exists in the address space, but there 5515274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5525274f052SJens Axboe * through to last case. 5535274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5545274f052SJens Axboe * the page cache and avoid the copy. 5555274f052SJens Axboe * 55683f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55783f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 55883f9135bSJens Axboe * file address space page cache. This is possible if no one else has 55983f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 56083f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 56183f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5625274f052SJens Axboe */ 5635274f052SJens Axboe static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 5645274f052SJens Axboe struct splice_desc *sd) 5655274f052SJens Axboe { 5665274f052SJens Axboe struct file *file = sd->file; 5675274f052SJens Axboe struct address_space *mapping = file->f_mapping; 5683e7ee3e7SJens Axboe gfp_t gfp_mask = mapping_gfp_mask(mapping); 569016b661eSJens Axboe unsigned int offset, this_len; 5705274f052SJens Axboe struct page *page; 5715274f052SJens Axboe pgoff_t index; 5725abc97aaSJens Axboe char *src; 5733e7ee3e7SJens Axboe int ret; 5745274f052SJens Axboe 5755274f052SJens Axboe /* 57649d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5775274f052SJens Axboe */ 5785274f052SJens Axboe src = buf->ops->map(file, info, buf); 5795274f052SJens Axboe if (IS_ERR(src)) 5805274f052SJens Axboe return PTR_ERR(src); 5815274f052SJens Axboe 5825274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5835274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5845274f052SJens Axboe 585016b661eSJens Axboe this_len = sd->len; 586016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 587016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 588016b661eSJens Axboe 5895abc97aaSJens Axboe /* 59073d62d83SIngo Molnar * Reuse buf page, if SPLICE_F_MOVE is set. 5915abc97aaSJens Axboe */ 5925abc97aaSJens Axboe if (sd->flags & SPLICE_F_MOVE) { 59383f9135bSJens Axboe /* 59483f9135bSJens Axboe * If steal succeeds, buf->page is now pruned from the vm 5959e0267c2SJens Axboe * side (LRU and page cache) and we can reuse it. The page 5969e0267c2SJens Axboe * will also be looked on successful return. 59783f9135bSJens Axboe */ 5985abc97aaSJens Axboe if (buf->ops->steal(info, buf)) 5995abc97aaSJens Axboe goto find_page; 6005abc97aaSJens Axboe 6015abc97aaSJens Axboe page = buf->page; 6023e7ee3e7SJens Axboe if (add_to_page_cache(page, mapping, index, gfp_mask)) 6035abc97aaSJens Axboe goto find_page; 6043e7ee3e7SJens Axboe 6053e7ee3e7SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 6063e7ee3e7SJens Axboe lru_cache_add(page); 6075abc97aaSJens Axboe } else { 6085274f052SJens Axboe find_page: 6099e0267c2SJens Axboe page = find_lock_page(mapping, index); 6109e0267c2SJens Axboe if (!page) { 6115274f052SJens Axboe ret = -ENOMEM; 6129e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 6139e0267c2SJens Axboe if (unlikely(!page)) 6149aefe431SDave Jones goto out_nomem; 6155274f052SJens Axboe 6165274f052SJens Axboe /* 6179e0267c2SJens Axboe * This will also lock the page 6189e0267c2SJens Axboe */ 6199e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 6209e0267c2SJens Axboe gfp_mask); 6219e0267c2SJens Axboe if (unlikely(ret)) 6229e0267c2SJens Axboe goto out; 6239e0267c2SJens Axboe } 6249e0267c2SJens Axboe 6259e0267c2SJens Axboe /* 6269e0267c2SJens Axboe * We get here with the page locked. If the page is also 6279e0267c2SJens Axboe * uptodate, we don't need to do more. If it isn't, we 6289e0267c2SJens Axboe * may need to bring it in if we are not going to overwrite 6299e0267c2SJens Axboe * the full page. 6305274f052SJens Axboe */ 6315274f052SJens Axboe if (!PageUptodate(page)) { 632016b661eSJens Axboe if (this_len < PAGE_CACHE_SIZE) { 6335274f052SJens Axboe ret = mapping->a_ops->readpage(file, page); 6345274f052SJens Axboe if (unlikely(ret)) 6355274f052SJens Axboe goto out; 6365274f052SJens Axboe 6375274f052SJens Axboe lock_page(page); 6385274f052SJens Axboe 6395274f052SJens Axboe if (!PageUptodate(page)) { 6405274f052SJens Axboe /* 64173d62d83SIngo Molnar * Page got invalidated, repeat. 6425274f052SJens Axboe */ 6435274f052SJens Axboe if (!page->mapping) { 6445274f052SJens Axboe unlock_page(page); 6455274f052SJens Axboe page_cache_release(page); 6465274f052SJens Axboe goto find_page; 6475274f052SJens Axboe } 6485274f052SJens Axboe ret = -EIO; 6495274f052SJens Axboe goto out; 6505274f052SJens Axboe } 6519e0267c2SJens Axboe } else 6525274f052SJens Axboe SetPageUptodate(page); 6535274f052SJens Axboe } 6545274f052SJens Axboe } 6555274f052SJens Axboe 656016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 6574f6f0bd2SJens Axboe if (ret == AOP_TRUNCATED_PAGE) { 6584f6f0bd2SJens Axboe page_cache_release(page); 6594f6f0bd2SJens Axboe goto find_page; 6604f6f0bd2SJens Axboe } else if (ret) 6615274f052SJens Axboe goto out; 6625274f052SJens Axboe 6633e7ee3e7SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { 6645abc97aaSJens Axboe char *dst = kmap_atomic(page, KM_USER0); 6655abc97aaSJens Axboe 666016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6675274f052SJens Axboe flush_dcache_page(page); 6685274f052SJens Axboe kunmap_atomic(dst, KM_USER0); 6695abc97aaSJens Axboe } 6705274f052SJens Axboe 671016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 6724f6f0bd2SJens Axboe if (ret == AOP_TRUNCATED_PAGE) { 6734f6f0bd2SJens Axboe page_cache_release(page); 6744f6f0bd2SJens Axboe goto find_page; 6754f6f0bd2SJens Axboe } else if (ret) 6765274f052SJens Axboe goto out; 6775274f052SJens Axboe 678016b661eSJens Axboe /* 679016b661eSJens Axboe * Return the number of bytes written. 680016b661eSJens Axboe */ 681016b661eSJens Axboe ret = this_len; 682c7f21e4fSJens Axboe mark_page_accessed(page); 6834f6f0bd2SJens Axboe balance_dirty_pages_ratelimited(mapping); 6845274f052SJens Axboe out: 6859e0267c2SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) 6865274f052SJens Axboe page_cache_release(page); 6879e0267c2SJens Axboe 6884f6f0bd2SJens Axboe unlock_page(page); 6899aefe431SDave Jones out_nomem: 6905274f052SJens Axboe buf->ops->unmap(info, buf); 6915274f052SJens Axboe return ret; 6925274f052SJens Axboe } 6935274f052SJens Axboe 69483f9135bSJens Axboe /* 69583f9135bSJens Axboe * Pipe input worker. Most of this logic works like a regular pipe, the 69683f9135bSJens Axboe * key here is the 'actor' worker passed in that actually moves the data 69783f9135bSJens Axboe * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. 69883f9135bSJens Axboe */ 69900522fb4SJens Axboe ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 700cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags, 7015274f052SJens Axboe splice_actor *actor) 7025274f052SJens Axboe { 7035274f052SJens Axboe int ret, do_wakeup, err; 7045274f052SJens Axboe struct splice_desc sd; 7055274f052SJens Axboe 7065274f052SJens Axboe ret = 0; 7075274f052SJens Axboe do_wakeup = 0; 7085274f052SJens Axboe 7095274f052SJens Axboe sd.total_len = len; 7105274f052SJens Axboe sd.flags = flags; 7115274f052SJens Axboe sd.file = out; 712cbb7e577SJens Axboe sd.pos = *ppos; 7135274f052SJens Axboe 7143a326a2cSIngo Molnar if (pipe->inode) 7153a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 7165274f052SJens Axboe 7175274f052SJens Axboe for (;;) { 7186f767b04SJens Axboe if (pipe->nrbufs) { 7196f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 7205274f052SJens Axboe struct pipe_buf_operations *ops = buf->ops; 7215274f052SJens Axboe 7225274f052SJens Axboe sd.len = buf->len; 7235274f052SJens Axboe if (sd.len > sd.total_len) 7245274f052SJens Axboe sd.len = sd.total_len; 7255274f052SJens Axboe 7263a326a2cSIngo Molnar err = actor(pipe, buf, &sd); 727016b661eSJens Axboe if (err <= 0) { 7285274f052SJens Axboe if (!ret && err != -ENODATA) 7295274f052SJens Axboe ret = err; 7305274f052SJens Axboe 7315274f052SJens Axboe break; 7325274f052SJens Axboe } 7335274f052SJens Axboe 734016b661eSJens Axboe ret += err; 735016b661eSJens Axboe buf->offset += err; 736016b661eSJens Axboe buf->len -= err; 737016b661eSJens Axboe 738016b661eSJens Axboe sd.len -= err; 739016b661eSJens Axboe sd.pos += err; 740016b661eSJens Axboe sd.total_len -= err; 741016b661eSJens Axboe if (sd.len) 742016b661eSJens Axboe continue; 74373d62d83SIngo Molnar 7445274f052SJens Axboe if (!buf->len) { 7455274f052SJens Axboe buf->ops = NULL; 7463a326a2cSIngo Molnar ops->release(pipe, buf); 7476f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7486f767b04SJens Axboe pipe->nrbufs--; 7496f767b04SJens Axboe if (pipe->inode) 7505274f052SJens Axboe do_wakeup = 1; 7515274f052SJens Axboe } 7525274f052SJens Axboe 7535274f052SJens Axboe if (!sd.total_len) 7545274f052SJens Axboe break; 7555274f052SJens Axboe } 7565274f052SJens Axboe 7576f767b04SJens Axboe if (pipe->nrbufs) 7585274f052SJens Axboe continue; 7593a326a2cSIngo Molnar if (!pipe->writers) 7605274f052SJens Axboe break; 7613a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7625274f052SJens Axboe if (ret) 7635274f052SJens Axboe break; 7645274f052SJens Axboe } 7655274f052SJens Axboe 76629e35094SLinus Torvalds if (flags & SPLICE_F_NONBLOCK) { 76729e35094SLinus Torvalds if (!ret) 76829e35094SLinus Torvalds ret = -EAGAIN; 76929e35094SLinus Torvalds break; 77029e35094SLinus Torvalds } 77129e35094SLinus Torvalds 7725274f052SJens Axboe if (signal_pending(current)) { 7735274f052SJens Axboe if (!ret) 7745274f052SJens Axboe ret = -ERESTARTSYS; 7755274f052SJens Axboe break; 7765274f052SJens Axboe } 7775274f052SJens Axboe 7785274f052SJens Axboe if (do_wakeup) { 779c0bd1f65SJens Axboe smp_mb(); 7803a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7813a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7823a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7835274f052SJens Axboe do_wakeup = 0; 7845274f052SJens Axboe } 7855274f052SJens Axboe 7863a326a2cSIngo Molnar pipe_wait(pipe); 7875274f052SJens Axboe } 7885274f052SJens Axboe 7893a326a2cSIngo Molnar if (pipe->inode) 7903a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 7915274f052SJens Axboe 7925274f052SJens Axboe if (do_wakeup) { 793c0bd1f65SJens Axboe smp_mb(); 7943a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7953a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7963a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7975274f052SJens Axboe } 7985274f052SJens Axboe 7995274f052SJens Axboe return ret; 8005274f052SJens Axboe } 8015274f052SJens Axboe 80283f9135bSJens Axboe /** 80383f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8043a326a2cSIngo Molnar * @pipe: pipe info 80583f9135bSJens Axboe * @out: file to write to 80683f9135bSJens Axboe * @len: number of bytes to splice 80783f9135bSJens Axboe * @flags: splice modifier flags 80883f9135bSJens Axboe * 80983f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 81083f9135bSJens Axboe * the given pipe inode to the given file. 81183f9135bSJens Axboe * 81283f9135bSJens Axboe */ 8133a326a2cSIngo Molnar ssize_t 8143a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 815cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8165274f052SJens Axboe { 8174f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8183a326a2cSIngo Molnar ssize_t ret; 8193a326a2cSIngo Molnar 82000522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 821a4514ebdSJens Axboe if (ret > 0) { 822a4514ebdSJens Axboe struct inode *inode = mapping->host; 823a4514ebdSJens Axboe 824a4514ebdSJens Axboe *ppos += ret; 8254f6f0bd2SJens Axboe 8264f6f0bd2SJens Axboe /* 827a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 828a4514ebdSJens Axboe * sync it. 8294f6f0bd2SJens Axboe */ 830a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8314f6f0bd2SJens Axboe int err; 8324f6f0bd2SJens Axboe 8334f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 834a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8354f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8364f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8374f6f0bd2SJens Axboe 8384f6f0bd2SJens Axboe if (err) 8394f6f0bd2SJens Axboe ret = err; 8404f6f0bd2SJens Axboe } 841a4514ebdSJens Axboe } 8424f6f0bd2SJens Axboe 8434f6f0bd2SJens Axboe return ret; 8445274f052SJens Axboe } 8455274f052SJens Axboe 846059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 847059a8f37SJens Axboe 84883f9135bSJens Axboe /** 84983f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 85083f9135bSJens Axboe * @inode: pipe inode 85183f9135bSJens Axboe * @out: socket to write to 85283f9135bSJens Axboe * @len: number of bytes to splice 85383f9135bSJens Axboe * @flags: splice modifier flags 85483f9135bSJens Axboe * 85583f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 85683f9135bSJens Axboe * is involved. 85783f9135bSJens Axboe * 85883f9135bSJens Axboe */ 8593a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 860cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8615274f052SJens Axboe { 86200522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8635274f052SJens Axboe } 8645274f052SJens Axboe 865059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 866a0f06780SJeff Garzik 86783f9135bSJens Axboe /* 86883f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 86983f9135bSJens Axboe */ 8703a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 871cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8725274f052SJens Axboe { 8735274f052SJens Axboe int ret; 8745274f052SJens Axboe 87549570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 8765274f052SJens Axboe return -EINVAL; 8775274f052SJens Axboe 87849570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 8795274f052SJens Axboe return -EBADF; 8805274f052SJens Axboe 881cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 8825274f052SJens Axboe if (unlikely(ret < 0)) 8835274f052SJens Axboe return ret; 8845274f052SJens Axboe 885cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 8865274f052SJens Axboe } 8875274f052SJens Axboe 88883f9135bSJens Axboe /* 88983f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 89083f9135bSJens Axboe */ 891cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 892cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 893cbb7e577SJens Axboe unsigned int flags) 8945274f052SJens Axboe { 895cbb7e577SJens Axboe loff_t isize, left; 8965274f052SJens Axboe int ret; 8975274f052SJens Axboe 89849570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 8995274f052SJens Axboe return -EINVAL; 9005274f052SJens Axboe 90149570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9025274f052SJens Axboe return -EBADF; 9035274f052SJens Axboe 904cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9055274f052SJens Axboe if (unlikely(ret < 0)) 9065274f052SJens Axboe return ret; 9075274f052SJens Axboe 9085274f052SJens Axboe isize = i_size_read(in->f_mapping->host); 909cbb7e577SJens Axboe if (unlikely(*ppos >= isize)) 9105274f052SJens Axboe return 0; 9115274f052SJens Axboe 912cbb7e577SJens Axboe left = isize - *ppos; 91349570e9bSJens Axboe if (unlikely(left < len)) 9145274f052SJens Axboe len = left; 9155274f052SJens Axboe 916cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9175274f052SJens Axboe } 9185274f052SJens Axboe 919cbb7e577SJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 920cbb7e577SJens Axboe size_t len, unsigned int flags) 921b92ce558SJens Axboe { 922b92ce558SJens Axboe struct pipe_inode_info *pipe; 923b92ce558SJens Axboe long ret, bytes; 924cbb7e577SJens Axboe loff_t out_off; 925b92ce558SJens Axboe umode_t i_mode; 926b92ce558SJens Axboe int i; 927b92ce558SJens Axboe 928b92ce558SJens Axboe /* 929b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 930b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 931b92ce558SJens Axboe * piped splicing for that! 932b92ce558SJens Axboe */ 933b92ce558SJens Axboe i_mode = in->f_dentry->d_inode->i_mode; 934b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 935b92ce558SJens Axboe return -EINVAL; 936b92ce558SJens Axboe 937b92ce558SJens Axboe /* 938b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 939b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 940b92ce558SJens Axboe */ 941b92ce558SJens Axboe pipe = current->splice_pipe; 94249570e9bSJens Axboe if (unlikely(!pipe)) { 943b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 944b92ce558SJens Axboe if (!pipe) 945b92ce558SJens Axboe return -ENOMEM; 946b92ce558SJens Axboe 947b92ce558SJens Axboe /* 948b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 94900522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 950b92ce558SJens Axboe * PIPE_READERS appropriately. 951b92ce558SJens Axboe */ 952b92ce558SJens Axboe pipe->readers = 1; 953b92ce558SJens Axboe 954b92ce558SJens Axboe current->splice_pipe = pipe; 955b92ce558SJens Axboe } 956b92ce558SJens Axboe 957b92ce558SJens Axboe /* 95873d62d83SIngo Molnar * Do the splice. 959b92ce558SJens Axboe */ 960b92ce558SJens Axboe ret = 0; 961b92ce558SJens Axboe bytes = 0; 962cbb7e577SJens Axboe out_off = 0; 963b92ce558SJens Axboe 964b92ce558SJens Axboe while (len) { 965b92ce558SJens Axboe size_t read_len, max_read_len; 966b92ce558SJens Axboe 967b92ce558SJens Axboe /* 968b92ce558SJens Axboe * Do at most PIPE_BUFFERS pages worth of transfer: 969b92ce558SJens Axboe */ 970b92ce558SJens Axboe max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); 971b92ce558SJens Axboe 972cbb7e577SJens Axboe ret = do_splice_to(in, ppos, pipe, max_read_len, flags); 973b92ce558SJens Axboe if (unlikely(ret < 0)) 974b92ce558SJens Axboe goto out_release; 975b92ce558SJens Axboe 976b92ce558SJens Axboe read_len = ret; 977b92ce558SJens Axboe 978b92ce558SJens Axboe /* 979b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 980b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 981b92ce558SJens Axboe * could get stuck data in the internal pipe: 982b92ce558SJens Axboe */ 983cbb7e577SJens Axboe ret = do_splice_from(pipe, out, &out_off, read_len, 984b92ce558SJens Axboe flags & ~SPLICE_F_NONBLOCK); 985b92ce558SJens Axboe if (unlikely(ret < 0)) 986b92ce558SJens Axboe goto out_release; 987b92ce558SJens Axboe 988b92ce558SJens Axboe bytes += ret; 989b92ce558SJens Axboe len -= ret; 990b92ce558SJens Axboe 991b92ce558SJens Axboe /* 992b92ce558SJens Axboe * In nonblocking mode, if we got back a short read then 993b92ce558SJens Axboe * that was due to either an IO error or due to the 994b92ce558SJens Axboe * pagecache entry not being there. In the IO error case 995b92ce558SJens Axboe * the _next_ splice attempt will produce a clean IO error 996b92ce558SJens Axboe * return value (not a short read), so in both cases it's 997b92ce558SJens Axboe * correct to break out of the loop here: 998b92ce558SJens Axboe */ 999b92ce558SJens Axboe if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) 1000b92ce558SJens Axboe break; 1001b92ce558SJens Axboe } 1002b92ce558SJens Axboe 1003b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1004b92ce558SJens Axboe 1005b92ce558SJens Axboe return bytes; 1006b92ce558SJens Axboe 1007b92ce558SJens Axboe out_release: 1008b92ce558SJens Axboe /* 1009b92ce558SJens Axboe * If we did an incomplete transfer we must release 1010b92ce558SJens Axboe * the pipe buffers in question: 1011b92ce558SJens Axboe */ 1012b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1013b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1014b92ce558SJens Axboe 1015b92ce558SJens Axboe if (buf->ops) { 1016b92ce558SJens Axboe buf->ops->release(pipe, buf); 1017b92ce558SJens Axboe buf->ops = NULL; 1018b92ce558SJens Axboe } 1019b92ce558SJens Axboe } 1020b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1021b92ce558SJens Axboe 1022b92ce558SJens Axboe /* 1023b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1024b92ce558SJens Axboe */ 1025b92ce558SJens Axboe if (bytes > 0) 1026b92ce558SJens Axboe return bytes; 1027b92ce558SJens Axboe 1028b92ce558SJens Axboe return ret; 1029b92ce558SJens Axboe } 1030b92ce558SJens Axboe 1031b92ce558SJens Axboe EXPORT_SYMBOL(do_splice_direct); 1032b92ce558SJens Axboe 103383f9135bSJens Axboe /* 103483f9135bSJens Axboe * Determine where to splice to/from. 103583f9135bSJens Axboe */ 1036529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1037529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1038529565dcSIngo Molnar size_t len, unsigned int flags) 10395274f052SJens Axboe { 10403a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1041cbb7e577SJens Axboe loff_t offset, *off; 1042a4514ebdSJens Axboe long ret; 10435274f052SJens Axboe 10443a326a2cSIngo Molnar pipe = in->f_dentry->d_inode->i_pipe; 1045529565dcSIngo Molnar if (pipe) { 1046529565dcSIngo Molnar if (off_in) 1047529565dcSIngo Molnar return -ESPIPE; 1048b92ce558SJens Axboe if (off_out) { 1049b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1050b92ce558SJens Axboe return -EINVAL; 1051cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1052b92ce558SJens Axboe return -EFAULT; 1053cbb7e577SJens Axboe off = &offset; 1054cbb7e577SJens Axboe } else 1055cbb7e577SJens Axboe off = &out->f_pos; 1056529565dcSIngo Molnar 1057a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1058a4514ebdSJens Axboe 1059a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1060a4514ebdSJens Axboe ret = -EFAULT; 1061a4514ebdSJens Axboe 1062a4514ebdSJens Axboe return ret; 1063529565dcSIngo Molnar } 10645274f052SJens Axboe 10653a326a2cSIngo Molnar pipe = out->f_dentry->d_inode->i_pipe; 1066529565dcSIngo Molnar if (pipe) { 1067529565dcSIngo Molnar if (off_out) 1068529565dcSIngo Molnar return -ESPIPE; 1069b92ce558SJens Axboe if (off_in) { 1070b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1071b92ce558SJens Axboe return -EINVAL; 1072cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1073b92ce558SJens Axboe return -EFAULT; 1074cbb7e577SJens Axboe off = &offset; 1075cbb7e577SJens Axboe } else 1076cbb7e577SJens Axboe off = &in->f_pos; 1077529565dcSIngo Molnar 1078a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1079a4514ebdSJens Axboe 1080a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1081a4514ebdSJens Axboe ret = -EFAULT; 1082a4514ebdSJens Axboe 1083a4514ebdSJens Axboe return ret; 1084529565dcSIngo Molnar } 10855274f052SJens Axboe 10865274f052SJens Axboe return -EINVAL; 10875274f052SJens Axboe } 10885274f052SJens Axboe 1089912d35f8SJens Axboe /* 1090912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1091912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1092912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1093912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1094912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1095912d35f8SJens Axboe */ 1096912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1097912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 1098912d35f8SJens Axboe struct partial_page *partial) 1099912d35f8SJens Axboe { 1100912d35f8SJens Axboe int buffers = 0, error = 0; 1101912d35f8SJens Axboe 1102912d35f8SJens Axboe /* 1103912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1104912d35f8SJens Axboe * across a "get_user()". 1105912d35f8SJens Axboe */ 1106912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1107912d35f8SJens Axboe 1108912d35f8SJens Axboe while (nr_vecs) { 1109912d35f8SJens Axboe unsigned long off, npages; 1110912d35f8SJens Axboe void __user *base; 1111912d35f8SJens Axboe size_t len; 1112912d35f8SJens Axboe int i; 1113912d35f8SJens Axboe 1114912d35f8SJens Axboe /* 1115912d35f8SJens Axboe * Get user address base and length for this iovec. 1116912d35f8SJens Axboe */ 1117912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1118912d35f8SJens Axboe if (unlikely(error)) 1119912d35f8SJens Axboe break; 1120912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1121912d35f8SJens Axboe if (unlikely(error)) 1122912d35f8SJens Axboe break; 1123912d35f8SJens Axboe 1124912d35f8SJens Axboe /* 1125912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1126912d35f8SJens Axboe */ 1127912d35f8SJens Axboe if (unlikely(!len)) 1128912d35f8SJens Axboe break; 1129912d35f8SJens Axboe error = -EFAULT; 1130912d35f8SJens Axboe if (unlikely(!base)) 1131912d35f8SJens Axboe break; 1132912d35f8SJens Axboe 1133912d35f8SJens Axboe /* 1134912d35f8SJens Axboe * Get this base offset and number of pages, then map 1135912d35f8SJens Axboe * in the user pages. 1136912d35f8SJens Axboe */ 1137912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 1138912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1139912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1140912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1141912d35f8SJens Axboe 1142912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1143912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1144912d35f8SJens Axboe &pages[buffers], NULL); 1145912d35f8SJens Axboe 1146912d35f8SJens Axboe if (unlikely(error <= 0)) 1147912d35f8SJens Axboe break; 1148912d35f8SJens Axboe 1149912d35f8SJens Axboe /* 1150912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1151912d35f8SJens Axboe */ 1152912d35f8SJens Axboe for (i = 0; i < error; i++) { 1153912d35f8SJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE) - off; 1154912d35f8SJens Axboe 1155912d35f8SJens Axboe partial[buffers].offset = off; 1156912d35f8SJens Axboe partial[buffers].len = plen; 1157912d35f8SJens Axboe 1158912d35f8SJens Axboe off = 0; 1159912d35f8SJens Axboe len -= plen; 1160912d35f8SJens Axboe buffers++; 1161912d35f8SJens Axboe } 1162912d35f8SJens Axboe 1163912d35f8SJens Axboe /* 1164912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1165912d35f8SJens Axboe * means we have to move some of this into a pipe to 1166912d35f8SJens Axboe * be able to continue. 1167912d35f8SJens Axboe */ 1168912d35f8SJens Axboe if (len) 1169912d35f8SJens Axboe break; 1170912d35f8SJens Axboe 1171912d35f8SJens Axboe /* 1172912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1173912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1174912d35f8SJens Axboe * room for. 1175912d35f8SJens Axboe */ 1176912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1177912d35f8SJens Axboe break; 1178912d35f8SJens Axboe 1179912d35f8SJens Axboe nr_vecs--; 1180912d35f8SJens Axboe iov++; 1181912d35f8SJens Axboe } 1182912d35f8SJens Axboe 1183912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1184912d35f8SJens Axboe 1185912d35f8SJens Axboe if (buffers) 1186912d35f8SJens Axboe return buffers; 1187912d35f8SJens Axboe 1188912d35f8SJens Axboe return error; 1189912d35f8SJens Axboe } 1190912d35f8SJens Axboe 1191912d35f8SJens Axboe /* 1192912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1193912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1194912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1195912d35f8SJens Axboe * 1196912d35f8SJens Axboe * Note that vmsplice only supports splicing _from_ user memory to a pipe, 1197912d35f8SJens Axboe * not the other way around. Splicing from user memory is a simple operation 1198912d35f8SJens Axboe * that can be supported without any funky alignment restrictions or nasty 1199912d35f8SJens Axboe * vm tricks. We simply map in the user memory and fill them into a pipe. 1200912d35f8SJens Axboe * The reverse isn't quite as easy, though. There are two possible solutions 1201912d35f8SJens Axboe * for that: 1202912d35f8SJens Axboe * 1203912d35f8SJens Axboe * - memcpy() the data internally, at which point we might as well just 1204912d35f8SJens Axboe * do a regular read() on the buffer anyway. 1205912d35f8SJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 1206912d35f8SJens Axboe * has restriction limitations on both ends of the pipe). 1207912d35f8SJens Axboe * 1208912d35f8SJens Axboe * Alas, it isn't here. 1209912d35f8SJens Axboe * 1210912d35f8SJens Axboe */ 1211912d35f8SJens Axboe static long do_vmsplice(struct file *file, const struct iovec __user *iov, 1212912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1213912d35f8SJens Axboe { 1214912d35f8SJens Axboe struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; 1215912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1216912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1217912d35f8SJens Axboe struct splice_pipe_desc spd = { 1218912d35f8SJens Axboe .pages = pages, 1219912d35f8SJens Axboe .partial = partial, 1220912d35f8SJens Axboe .flags = flags, 1221912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1222912d35f8SJens Axboe }; 1223912d35f8SJens Axboe 1224912d35f8SJens Axboe if (unlikely(!pipe)) 1225912d35f8SJens Axboe return -EBADF; 1226912d35f8SJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 1227912d35f8SJens Axboe return -EINVAL; 1228912d35f8SJens Axboe else if (unlikely(!nr_segs)) 1229912d35f8SJens Axboe return 0; 1230912d35f8SJens Axboe 1231912d35f8SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial); 1232912d35f8SJens Axboe if (spd.nr_pages <= 0) 1233912d35f8SJens Axboe return spd.nr_pages; 1234912d35f8SJens Axboe 123500522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1236912d35f8SJens Axboe } 1237912d35f8SJens Axboe 1238912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1239912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1240912d35f8SJens Axboe { 1241912d35f8SJens Axboe struct file *file; 1242912d35f8SJens Axboe long error; 1243912d35f8SJens Axboe int fput; 1244912d35f8SJens Axboe 1245912d35f8SJens Axboe error = -EBADF; 1246912d35f8SJens Axboe file = fget_light(fd, &fput); 1247912d35f8SJens Axboe if (file) { 1248912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 1249912d35f8SJens Axboe error = do_vmsplice(file, iov, nr_segs, flags); 1250912d35f8SJens Axboe 1251912d35f8SJens Axboe fput_light(file, fput); 1252912d35f8SJens Axboe } 1253912d35f8SJens Axboe 1254912d35f8SJens Axboe return error; 1255912d35f8SJens Axboe } 1256912d35f8SJens Axboe 1257529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1258529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1259529565dcSIngo Molnar size_t len, unsigned int flags) 12605274f052SJens Axboe { 12615274f052SJens Axboe long error; 12625274f052SJens Axboe struct file *in, *out; 12635274f052SJens Axboe int fput_in, fput_out; 12645274f052SJens Axboe 12655274f052SJens Axboe if (unlikely(!len)) 12665274f052SJens Axboe return 0; 12675274f052SJens Axboe 12685274f052SJens Axboe error = -EBADF; 1269529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 12705274f052SJens Axboe if (in) { 12715274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1272529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 12735274f052SJens Axboe if (out) { 12745274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1275529565dcSIngo Molnar error = do_splice(in, off_in, 1276529565dcSIngo Molnar out, off_out, 1277529565dcSIngo Molnar len, flags); 12785274f052SJens Axboe fput_light(out, fput_out); 12795274f052SJens Axboe } 12805274f052SJens Axboe } 12815274f052SJens Axboe 12825274f052SJens Axboe fput_light(in, fput_in); 12835274f052SJens Axboe } 12845274f052SJens Axboe 12855274f052SJens Axboe return error; 12865274f052SJens Axboe } 128770524490SJens Axboe 128870524490SJens Axboe /* 128970524490SJens Axboe * Link contents of ipipe to opipe. 129070524490SJens Axboe */ 129170524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 129270524490SJens Axboe struct pipe_inode_info *opipe, 129370524490SJens Axboe size_t len, unsigned int flags) 129470524490SJens Axboe { 129570524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 12962a27250eSJens Axboe int ret, do_wakeup, i, ipipe_first; 12972a27250eSJens Axboe 12982a27250eSJens Axboe ret = do_wakeup = ipipe_first = 0; 129970524490SJens Axboe 130070524490SJens Axboe /* 130170524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 130270524490SJens Axboe * grabbing by inode address. Otherwise two different processes 130370524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 130470524490SJens Axboe */ 130570524490SJens Axboe if (ipipe->inode < opipe->inode) { 13062a27250eSJens Axboe ipipe_first = 1; 130770524490SJens Axboe mutex_lock(&ipipe->inode->i_mutex); 130870524490SJens Axboe mutex_lock(&opipe->inode->i_mutex); 130970524490SJens Axboe } else { 131070524490SJens Axboe mutex_lock(&opipe->inode->i_mutex); 131170524490SJens Axboe mutex_lock(&ipipe->inode->i_mutex); 131270524490SJens Axboe } 131370524490SJens Axboe 131470524490SJens Axboe for (i = 0;; i++) { 131570524490SJens Axboe if (!opipe->readers) { 131670524490SJens Axboe send_sig(SIGPIPE, current, 0); 131770524490SJens Axboe if (!ret) 131870524490SJens Axboe ret = -EPIPE; 131970524490SJens Axboe break; 132070524490SJens Axboe } 132170524490SJens Axboe if (ipipe->nrbufs - i) { 132270524490SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 132370524490SJens Axboe 132470524490SJens Axboe /* 132570524490SJens Axboe * If we have room, fill this buffer 132670524490SJens Axboe */ 132770524490SJens Axboe if (opipe->nrbufs < PIPE_BUFFERS) { 132870524490SJens Axboe int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 132970524490SJens Axboe 133070524490SJens Axboe /* 133170524490SJens Axboe * Get a reference to this pipe buffer, 133270524490SJens Axboe * so we can copy the contents over. 133370524490SJens Axboe */ 133470524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 133570524490SJens Axboe 133670524490SJens Axboe obuf = opipe->bufs + nbuf; 133770524490SJens Axboe *obuf = *ibuf; 133870524490SJens Axboe 133970524490SJens Axboe if (obuf->len > len) 134070524490SJens Axboe obuf->len = len; 134170524490SJens Axboe 134270524490SJens Axboe opipe->nrbufs++; 134370524490SJens Axboe do_wakeup = 1; 134470524490SJens Axboe ret += obuf->len; 134570524490SJens Axboe len -= obuf->len; 134670524490SJens Axboe 134770524490SJens Axboe if (!len) 134870524490SJens Axboe break; 134970524490SJens Axboe if (opipe->nrbufs < PIPE_BUFFERS) 135070524490SJens Axboe continue; 135170524490SJens Axboe } 135270524490SJens Axboe 135370524490SJens Axboe /* 135470524490SJens Axboe * We have input available, but no output room. 13552a27250eSJens Axboe * If we already copied data, return that. If we 13562a27250eSJens Axboe * need to drop the opipe lock, it must be ordered 13572a27250eSJens Axboe * last to avoid deadlocks. 135870524490SJens Axboe */ 13592a27250eSJens Axboe if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { 136070524490SJens Axboe if (!ret) 136170524490SJens Axboe ret = -EAGAIN; 136270524490SJens Axboe break; 136370524490SJens Axboe } 136470524490SJens Axboe if (signal_pending(current)) { 136570524490SJens Axboe if (!ret) 136670524490SJens Axboe ret = -ERESTARTSYS; 136770524490SJens Axboe break; 136870524490SJens Axboe } 136970524490SJens Axboe if (do_wakeup) { 137070524490SJens Axboe smp_mb(); 137170524490SJens Axboe if (waitqueue_active(&opipe->wait)) 137270524490SJens Axboe wake_up_interruptible(&opipe->wait); 137370524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 137470524490SJens Axboe do_wakeup = 0; 137570524490SJens Axboe } 137670524490SJens Axboe 137770524490SJens Axboe opipe->waiting_writers++; 137870524490SJens Axboe pipe_wait(opipe); 137970524490SJens Axboe opipe->waiting_writers--; 138070524490SJens Axboe continue; 138170524490SJens Axboe } 138270524490SJens Axboe 138370524490SJens Axboe /* 138470524490SJens Axboe * No input buffers, do the usual checks for available 138570524490SJens Axboe * writers and blocking and wait if necessary 138670524490SJens Axboe */ 138770524490SJens Axboe if (!ipipe->writers) 138870524490SJens Axboe break; 138970524490SJens Axboe if (!ipipe->waiting_writers) { 139070524490SJens Axboe if (ret) 139170524490SJens Axboe break; 139270524490SJens Axboe } 13932a27250eSJens Axboe /* 13942a27250eSJens Axboe * pipe_wait() drops the ipipe mutex. To avoid deadlocks 13952a27250eSJens Axboe * with another process, we can only safely do that if 13962a27250eSJens Axboe * the ipipe lock is ordered last. 13972a27250eSJens Axboe */ 13982a27250eSJens Axboe if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { 139970524490SJens Axboe if (!ret) 140070524490SJens Axboe ret = -EAGAIN; 140170524490SJens Axboe break; 140270524490SJens Axboe } 140370524490SJens Axboe if (signal_pending(current)) { 140470524490SJens Axboe if (!ret) 140570524490SJens Axboe ret = -ERESTARTSYS; 140670524490SJens Axboe break; 140770524490SJens Axboe } 140870524490SJens Axboe 140970524490SJens Axboe if (waitqueue_active(&ipipe->wait)) 141070524490SJens Axboe wake_up_interruptible_sync(&ipipe->wait); 141170524490SJens Axboe kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); 141270524490SJens Axboe 141370524490SJens Axboe pipe_wait(ipipe); 141470524490SJens Axboe } 141570524490SJens Axboe 141670524490SJens Axboe mutex_unlock(&ipipe->inode->i_mutex); 141770524490SJens Axboe mutex_unlock(&opipe->inode->i_mutex); 141870524490SJens Axboe 141970524490SJens Axboe if (do_wakeup) { 142070524490SJens Axboe smp_mb(); 142170524490SJens Axboe if (waitqueue_active(&opipe->wait)) 142270524490SJens Axboe wake_up_interruptible(&opipe->wait); 142370524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 142470524490SJens Axboe } 142570524490SJens Axboe 142670524490SJens Axboe return ret; 142770524490SJens Axboe } 142870524490SJens Axboe 142970524490SJens Axboe /* 143070524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 143170524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 143270524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 143370524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 143470524490SJens Axboe */ 143570524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 143670524490SJens Axboe unsigned int flags) 143770524490SJens Axboe { 143870524490SJens Axboe struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; 143970524490SJens Axboe struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; 144070524490SJens Axboe 144170524490SJens Axboe /* 144270524490SJens Axboe * Link ipipe to the two output pipes, consuming as we go along. 144370524490SJens Axboe */ 144470524490SJens Axboe if (ipipe && opipe) 144570524490SJens Axboe return link_pipe(ipipe, opipe, len, flags); 144670524490SJens Axboe 144770524490SJens Axboe return -EINVAL; 144870524490SJens Axboe } 144970524490SJens Axboe 145070524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 145170524490SJens Axboe { 145270524490SJens Axboe struct file *in; 145370524490SJens Axboe int error, fput_in; 145470524490SJens Axboe 145570524490SJens Axboe if (unlikely(!len)) 145670524490SJens Axboe return 0; 145770524490SJens Axboe 145870524490SJens Axboe error = -EBADF; 145970524490SJens Axboe in = fget_light(fdin, &fput_in); 146070524490SJens Axboe if (in) { 146170524490SJens Axboe if (in->f_mode & FMODE_READ) { 146270524490SJens Axboe int fput_out; 146370524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 146470524490SJens Axboe 146570524490SJens Axboe if (out) { 146670524490SJens Axboe if (out->f_mode & FMODE_WRITE) 146770524490SJens Axboe error = do_tee(in, out, len, flags); 146870524490SJens Axboe fput_light(out, fput_out); 146970524490SJens Axboe } 147070524490SJens Axboe } 147170524490SJens Axboe fput_light(in, fput_in); 147270524490SJens Axboe } 147370524490SJens Axboe 147470524490SJens Axboe return error; 147570524490SJens Axboe } 1476