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; 282912d35f8SJens Axboe int error; 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; 310912d35f8SJens Axboe for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) { 31182aa5d61SJens Axboe unsigned int this_len; 31282aa5d61SJens Axboe 31382aa5d61SJens Axboe if (!len) 31482aa5d61SJens Axboe break; 31582aa5d61SJens Axboe 31682aa5d61SJens Axboe /* 31782aa5d61SJens Axboe * this_len is the max we'll use from this page 31882aa5d61SJens Axboe */ 319ba5f5d90SAndrew Morton this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 3207480a904SJens Axboe find_page: 3215274f052SJens Axboe /* 3227480a904SJens Axboe * lookup the page for this index 3235274f052SJens Axboe */ 3247480a904SJens Axboe page = find_get_page(mapping, index); 3257480a904SJens Axboe if (!page) { 3267480a904SJens Axboe /* 3277480a904SJens Axboe * page didn't exist, allocate one 3287480a904SJens Axboe */ 3297480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3305274f052SJens Axboe if (!page) 3315274f052SJens Axboe break; 3325274f052SJens Axboe 3337480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3347480a904SJens Axboe mapping_gfp_mask(mapping)); 3355274f052SJens Axboe if (unlikely(error)) { 3365274f052SJens Axboe page_cache_release(page); 3375274f052SJens Axboe break; 3385274f052SJens Axboe } 3397480a904SJens Axboe 3407480a904SJens Axboe goto readpage; 3415274f052SJens Axboe } 3427480a904SJens Axboe 3437480a904SJens Axboe /* 3447480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3457480a904SJens Axboe */ 3467480a904SJens Axboe if (!PageUptodate(page)) { 347c4f895cbSJens Axboe /* 348c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 349c4f895cbSJens Axboe * for an in-flight io page 350c4f895cbSJens Axboe */ 351c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) 352c4f895cbSJens Axboe break; 353c4f895cbSJens Axboe 3547480a904SJens Axboe lock_page(page); 3557480a904SJens Axboe 3567480a904SJens Axboe /* 3577480a904SJens Axboe * page was truncated, stop here. if this isn't the 3587480a904SJens Axboe * first page, we'll just complete what we already 3597480a904SJens Axboe * added 3607480a904SJens Axboe */ 3617480a904SJens Axboe if (!page->mapping) { 3627480a904SJens Axboe unlock_page(page); 3637480a904SJens Axboe page_cache_release(page); 3647480a904SJens Axboe break; 3657480a904SJens Axboe } 3667480a904SJens Axboe /* 3677480a904SJens Axboe * page was already under io and is now done, great 3687480a904SJens Axboe */ 3697480a904SJens Axboe if (PageUptodate(page)) { 3707480a904SJens Axboe unlock_page(page); 3717480a904SJens Axboe goto fill_it; 3727480a904SJens Axboe } 3737480a904SJens Axboe 3747480a904SJens Axboe readpage: 3757480a904SJens Axboe /* 3767480a904SJens Axboe * need to read in the page 3777480a904SJens Axboe */ 3787480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 3797480a904SJens Axboe 3807480a904SJens Axboe if (unlikely(error)) { 3817480a904SJens Axboe page_cache_release(page); 3827480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 3837480a904SJens Axboe goto find_page; 3847480a904SJens Axboe break; 3857480a904SJens Axboe } 38691ad66efSJens Axboe 38791ad66efSJens Axboe /* 38891ad66efSJens Axboe * i_size must be checked after ->readpage(). 38991ad66efSJens Axboe */ 39091ad66efSJens Axboe isize = i_size_read(mapping->host); 39191ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 39291ad66efSJens Axboe if (unlikely(!isize || index > end_index)) { 39391ad66efSJens Axboe page_cache_release(page); 39491ad66efSJens Axboe break; 39591ad66efSJens Axboe } 39691ad66efSJens Axboe 39791ad66efSJens Axboe /* 39891ad66efSJens Axboe * if this is the last page, see if we need to shrink 39991ad66efSJens Axboe * the length and stop 40091ad66efSJens Axboe */ 40191ad66efSJens Axboe if (end_index == index) { 40291ad66efSJens Axboe loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); 403912d35f8SJens Axboe if (total_len + loff > isize) { 40491ad66efSJens Axboe page_cache_release(page); 40591ad66efSJens Axboe break; 40691ad66efSJens Axboe } 40791ad66efSJens Axboe /* 40891ad66efSJens Axboe * force quit after adding this page 40991ad66efSJens Axboe */ 410912d35f8SJens Axboe nr_pages = spd.nr_pages; 41182aa5d61SJens Axboe this_len = min(this_len, loff); 412912d35f8SJens Axboe loff = 0; 41391ad66efSJens Axboe } 4147480a904SJens Axboe } 4157480a904SJens Axboe fill_it: 416912d35f8SJens Axboe pages[spd.nr_pages] = page; 417912d35f8SJens Axboe partial[spd.nr_pages].offset = loff; 418912d35f8SJens Axboe partial[spd.nr_pages].len = this_len; 41982aa5d61SJens Axboe len -= this_len; 420912d35f8SJens Axboe total_len += this_len; 42191ad66efSJens Axboe loff = 0; 4225274f052SJens Axboe } 4235274f052SJens Axboe 424912d35f8SJens Axboe if (spd.nr_pages) 42500522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 42616c523ddSJens Axboe 4277480a904SJens Axboe return error; 4285274f052SJens Axboe } 4295274f052SJens Axboe 43083f9135bSJens Axboe /** 43183f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 43283f9135bSJens Axboe * @in: file to splice from 43383f9135bSJens Axboe * @pipe: pipe to splice to 43483f9135bSJens Axboe * @len: number of bytes to splice 43583f9135bSJens Axboe * @flags: splice modifier flags 43683f9135bSJens Axboe * 43783f9135bSJens Axboe * Will read pages from given file and fill them into a pipe. 43883f9135bSJens Axboe */ 439cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 440cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 441cbb7e577SJens Axboe unsigned int flags) 4425274f052SJens Axboe { 4435274f052SJens Axboe ssize_t spliced; 4445274f052SJens Axboe int ret; 4455274f052SJens Axboe 4465274f052SJens Axboe ret = 0; 4475274f052SJens Axboe spliced = 0; 4483a326a2cSIngo Molnar 4495274f052SJens Axboe while (len) { 450cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4515274f052SJens Axboe 452c4f895cbSJens Axboe if (ret < 0) 4535274f052SJens Axboe break; 454c4f895cbSJens Axboe else if (!ret) { 455c4f895cbSJens Axboe if (spliced) 456c4f895cbSJens Axboe break; 457c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 458c4f895cbSJens Axboe ret = -EAGAIN; 459c4f895cbSJens Axboe break; 460c4f895cbSJens Axboe } 461c4f895cbSJens Axboe } 4625274f052SJens Axboe 463cbb7e577SJens Axboe *ppos += ret; 4645274f052SJens Axboe len -= ret; 4655274f052SJens Axboe spliced += ret; 4665274f052SJens Axboe } 4675274f052SJens Axboe 4685274f052SJens Axboe if (spliced) 4695274f052SJens Axboe return spliced; 4705274f052SJens Axboe 4715274f052SJens Axboe return ret; 4725274f052SJens Axboe } 4735274f052SJens Axboe 474059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 475059a8f37SJens Axboe 4765274f052SJens Axboe /* 4774f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 478016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4795274f052SJens Axboe */ 4805274f052SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *info, 4815274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4825274f052SJens Axboe { 4835274f052SJens Axboe struct file *file = sd->file; 4845274f052SJens Axboe loff_t pos = sd->pos; 4855274f052SJens Axboe ssize_t ret; 4865274f052SJens Axboe void *ptr; 487b2b39fa4SJens Axboe int more; 4885274f052SJens Axboe 4895274f052SJens Axboe /* 49073d62d83SIngo Molnar * Sub-optimal, but we are limited by the pipe ->map. We don't 4915274f052SJens Axboe * need a kmap'ed buffer here, we just want to make sure we 4925274f052SJens Axboe * have the page pinned if the pipe page originates from the 49373d62d83SIngo Molnar * page cache. 4945274f052SJens Axboe */ 4955274f052SJens Axboe ptr = buf->ops->map(file, info, buf); 4965274f052SJens Axboe if (IS_ERR(ptr)) 4975274f052SJens Axboe return PTR_ERR(ptr); 4985274f052SJens Axboe 499b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5005274f052SJens Axboe 501016b661eSJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len, 502016b661eSJens Axboe &pos, more); 5035274f052SJens Axboe 5045274f052SJens Axboe buf->ops->unmap(info, buf); 505016b661eSJens Axboe return ret; 5065274f052SJens Axboe } 5075274f052SJens Axboe 5085274f052SJens Axboe /* 5095274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5105274f052SJens Axboe * basically three cases: 5115274f052SJens Axboe * 5125274f052SJens Axboe * - Destination page already exists in the address space and there 5135274f052SJens Axboe * are users of it. For that case we have no other option that 5145274f052SJens Axboe * copying the data. Tough luck. 5155274f052SJens Axboe * - Destination page already exists in the address space, but there 5165274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5175274f052SJens Axboe * through to last case. 5185274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5195274f052SJens Axboe * the page cache and avoid the copy. 5205274f052SJens Axboe * 52183f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 52283f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 52383f9135bSJens Axboe * file address space page cache. This is possible if no one else has 52483f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 52583f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 52683f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5275274f052SJens Axboe */ 5285274f052SJens Axboe static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 5295274f052SJens Axboe struct splice_desc *sd) 5305274f052SJens Axboe { 5315274f052SJens Axboe struct file *file = sd->file; 5325274f052SJens Axboe struct address_space *mapping = file->f_mapping; 5333e7ee3e7SJens Axboe gfp_t gfp_mask = mapping_gfp_mask(mapping); 534016b661eSJens Axboe unsigned int offset, this_len; 5355274f052SJens Axboe struct page *page; 5365274f052SJens Axboe pgoff_t index; 5375abc97aaSJens Axboe char *src; 5383e7ee3e7SJens Axboe int ret; 5395274f052SJens Axboe 5405274f052SJens Axboe /* 54149d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5425274f052SJens Axboe */ 5435274f052SJens Axboe src = buf->ops->map(file, info, buf); 5445274f052SJens Axboe if (IS_ERR(src)) 5455274f052SJens Axboe return PTR_ERR(src); 5465274f052SJens Axboe 5475274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5485274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5495274f052SJens Axboe 550016b661eSJens Axboe this_len = sd->len; 551016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 552016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 553016b661eSJens Axboe 5545abc97aaSJens Axboe /* 55573d62d83SIngo Molnar * Reuse buf page, if SPLICE_F_MOVE is set. 5565abc97aaSJens Axboe */ 5575abc97aaSJens Axboe if (sd->flags & SPLICE_F_MOVE) { 55883f9135bSJens Axboe /* 55983f9135bSJens Axboe * If steal succeeds, buf->page is now pruned from the vm 5609e0267c2SJens Axboe * side (LRU and page cache) and we can reuse it. The page 5619e0267c2SJens Axboe * will also be looked on successful return. 56283f9135bSJens Axboe */ 5635abc97aaSJens Axboe if (buf->ops->steal(info, buf)) 5645abc97aaSJens Axboe goto find_page; 5655abc97aaSJens Axboe 5665abc97aaSJens Axboe page = buf->page; 5673e7ee3e7SJens Axboe if (add_to_page_cache(page, mapping, index, gfp_mask)) 5685abc97aaSJens Axboe goto find_page; 5693e7ee3e7SJens Axboe 5703e7ee3e7SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 5713e7ee3e7SJens Axboe lru_cache_add(page); 5725abc97aaSJens Axboe } else { 5735274f052SJens Axboe find_page: 5749e0267c2SJens Axboe page = find_lock_page(mapping, index); 5759e0267c2SJens Axboe if (!page) { 5765274f052SJens Axboe ret = -ENOMEM; 5779e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5789e0267c2SJens Axboe if (unlikely(!page)) 5799aefe431SDave Jones goto out_nomem; 5805274f052SJens Axboe 5815274f052SJens Axboe /* 5829e0267c2SJens Axboe * This will also lock the page 5839e0267c2SJens Axboe */ 5849e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 5859e0267c2SJens Axboe gfp_mask); 5869e0267c2SJens Axboe if (unlikely(ret)) 5879e0267c2SJens Axboe goto out; 5889e0267c2SJens Axboe } 5899e0267c2SJens Axboe 5909e0267c2SJens Axboe /* 5919e0267c2SJens Axboe * We get here with the page locked. If the page is also 5929e0267c2SJens Axboe * uptodate, we don't need to do more. If it isn't, we 5939e0267c2SJens Axboe * may need to bring it in if we are not going to overwrite 5949e0267c2SJens Axboe * the full page. 5955274f052SJens Axboe */ 5965274f052SJens Axboe if (!PageUptodate(page)) { 597016b661eSJens Axboe if (this_len < PAGE_CACHE_SIZE) { 5985274f052SJens Axboe ret = mapping->a_ops->readpage(file, page); 5995274f052SJens Axboe if (unlikely(ret)) 6005274f052SJens Axboe goto out; 6015274f052SJens Axboe 6025274f052SJens Axboe lock_page(page); 6035274f052SJens Axboe 6045274f052SJens Axboe if (!PageUptodate(page)) { 6055274f052SJens Axboe /* 60673d62d83SIngo Molnar * Page got invalidated, repeat. 6075274f052SJens Axboe */ 6085274f052SJens Axboe if (!page->mapping) { 6095274f052SJens Axboe unlock_page(page); 6105274f052SJens Axboe page_cache_release(page); 6115274f052SJens Axboe goto find_page; 6125274f052SJens Axboe } 6135274f052SJens Axboe ret = -EIO; 6145274f052SJens Axboe goto out; 6155274f052SJens Axboe } 6169e0267c2SJens Axboe } else 6175274f052SJens Axboe SetPageUptodate(page); 6185274f052SJens Axboe } 6195274f052SJens Axboe } 6205274f052SJens Axboe 621016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 6224f6f0bd2SJens Axboe if (ret == AOP_TRUNCATED_PAGE) { 6234f6f0bd2SJens Axboe page_cache_release(page); 6244f6f0bd2SJens Axboe goto find_page; 6254f6f0bd2SJens Axboe } else if (ret) 6265274f052SJens Axboe goto out; 6275274f052SJens Axboe 6283e7ee3e7SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { 6295abc97aaSJens Axboe char *dst = kmap_atomic(page, KM_USER0); 6305abc97aaSJens Axboe 631016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6325274f052SJens Axboe flush_dcache_page(page); 6335274f052SJens Axboe kunmap_atomic(dst, KM_USER0); 6345abc97aaSJens Axboe } 6355274f052SJens Axboe 636016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 6374f6f0bd2SJens Axboe if (ret == AOP_TRUNCATED_PAGE) { 6384f6f0bd2SJens Axboe page_cache_release(page); 6394f6f0bd2SJens Axboe goto find_page; 6404f6f0bd2SJens Axboe } else if (ret) 6415274f052SJens Axboe goto out; 6425274f052SJens Axboe 643016b661eSJens Axboe /* 644016b661eSJens Axboe * Return the number of bytes written. 645016b661eSJens Axboe */ 646016b661eSJens Axboe ret = this_len; 647c7f21e4fSJens Axboe mark_page_accessed(page); 6484f6f0bd2SJens Axboe balance_dirty_pages_ratelimited(mapping); 6495274f052SJens Axboe out: 6509e0267c2SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) 6515274f052SJens Axboe page_cache_release(page); 6529e0267c2SJens Axboe 6534f6f0bd2SJens Axboe unlock_page(page); 6549aefe431SDave Jones out_nomem: 6555274f052SJens Axboe buf->ops->unmap(info, buf); 6565274f052SJens Axboe return ret; 6575274f052SJens Axboe } 6585274f052SJens Axboe 65983f9135bSJens Axboe /* 66083f9135bSJens Axboe * Pipe input worker. Most of this logic works like a regular pipe, the 66183f9135bSJens Axboe * key here is the 'actor' worker passed in that actually moves the data 66283f9135bSJens Axboe * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. 66383f9135bSJens Axboe */ 66400522fb4SJens Axboe ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 665cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags, 6665274f052SJens Axboe splice_actor *actor) 6675274f052SJens Axboe { 6685274f052SJens Axboe int ret, do_wakeup, err; 6695274f052SJens Axboe struct splice_desc sd; 6705274f052SJens Axboe 6715274f052SJens Axboe ret = 0; 6725274f052SJens Axboe do_wakeup = 0; 6735274f052SJens Axboe 6745274f052SJens Axboe sd.total_len = len; 6755274f052SJens Axboe sd.flags = flags; 6765274f052SJens Axboe sd.file = out; 677cbb7e577SJens Axboe sd.pos = *ppos; 6785274f052SJens Axboe 6793a326a2cSIngo Molnar if (pipe->inode) 6803a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 6815274f052SJens Axboe 6825274f052SJens Axboe for (;;) { 6836f767b04SJens Axboe if (pipe->nrbufs) { 6846f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 6855274f052SJens Axboe struct pipe_buf_operations *ops = buf->ops; 6865274f052SJens Axboe 6875274f052SJens Axboe sd.len = buf->len; 6885274f052SJens Axboe if (sd.len > sd.total_len) 6895274f052SJens Axboe sd.len = sd.total_len; 6905274f052SJens Axboe 6913a326a2cSIngo Molnar err = actor(pipe, buf, &sd); 692016b661eSJens Axboe if (err <= 0) { 6935274f052SJens Axboe if (!ret && err != -ENODATA) 6945274f052SJens Axboe ret = err; 6955274f052SJens Axboe 6965274f052SJens Axboe break; 6975274f052SJens Axboe } 6985274f052SJens Axboe 699016b661eSJens Axboe ret += err; 700016b661eSJens Axboe buf->offset += err; 701016b661eSJens Axboe buf->len -= err; 702016b661eSJens Axboe 703016b661eSJens Axboe sd.len -= err; 704016b661eSJens Axboe sd.pos += err; 705016b661eSJens Axboe sd.total_len -= err; 706016b661eSJens Axboe if (sd.len) 707016b661eSJens Axboe continue; 70873d62d83SIngo Molnar 7095274f052SJens Axboe if (!buf->len) { 7105274f052SJens Axboe buf->ops = NULL; 7113a326a2cSIngo Molnar ops->release(pipe, buf); 7126f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7136f767b04SJens Axboe pipe->nrbufs--; 7146f767b04SJens Axboe if (pipe->inode) 7155274f052SJens Axboe do_wakeup = 1; 7165274f052SJens Axboe } 7175274f052SJens Axboe 7185274f052SJens Axboe if (!sd.total_len) 7195274f052SJens Axboe break; 7205274f052SJens Axboe } 7215274f052SJens Axboe 7226f767b04SJens Axboe if (pipe->nrbufs) 7235274f052SJens Axboe continue; 7243a326a2cSIngo Molnar if (!pipe->writers) 7255274f052SJens Axboe break; 7263a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7275274f052SJens Axboe if (ret) 7285274f052SJens Axboe break; 7295274f052SJens Axboe } 7305274f052SJens Axboe 73129e35094SLinus Torvalds if (flags & SPLICE_F_NONBLOCK) { 73229e35094SLinus Torvalds if (!ret) 73329e35094SLinus Torvalds ret = -EAGAIN; 73429e35094SLinus Torvalds break; 73529e35094SLinus Torvalds } 73629e35094SLinus Torvalds 7375274f052SJens Axboe if (signal_pending(current)) { 7385274f052SJens Axboe if (!ret) 7395274f052SJens Axboe ret = -ERESTARTSYS; 7405274f052SJens Axboe break; 7415274f052SJens Axboe } 7425274f052SJens Axboe 7435274f052SJens Axboe if (do_wakeup) { 744c0bd1f65SJens Axboe smp_mb(); 7453a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7463a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7473a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7485274f052SJens Axboe do_wakeup = 0; 7495274f052SJens Axboe } 7505274f052SJens Axboe 7513a326a2cSIngo Molnar pipe_wait(pipe); 7525274f052SJens Axboe } 7535274f052SJens Axboe 7543a326a2cSIngo Molnar if (pipe->inode) 7553a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 7565274f052SJens Axboe 7575274f052SJens Axboe if (do_wakeup) { 758c0bd1f65SJens Axboe smp_mb(); 7593a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7603a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7613a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7625274f052SJens Axboe } 7635274f052SJens Axboe 7645274f052SJens Axboe return ret; 7655274f052SJens Axboe } 7665274f052SJens Axboe 76783f9135bSJens Axboe /** 76883f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 7693a326a2cSIngo Molnar * @pipe: pipe info 77083f9135bSJens Axboe * @out: file to write to 77183f9135bSJens Axboe * @len: number of bytes to splice 77283f9135bSJens Axboe * @flags: splice modifier flags 77383f9135bSJens Axboe * 77483f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 77583f9135bSJens Axboe * the given pipe inode to the given file. 77683f9135bSJens Axboe * 77783f9135bSJens Axboe */ 7783a326a2cSIngo Molnar ssize_t 7793a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 780cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 7815274f052SJens Axboe { 7824f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 7833a326a2cSIngo Molnar ssize_t ret; 7843a326a2cSIngo Molnar 78500522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 786a4514ebdSJens Axboe if (ret > 0) { 787a4514ebdSJens Axboe struct inode *inode = mapping->host; 788a4514ebdSJens Axboe 789a4514ebdSJens Axboe *ppos += ret; 7904f6f0bd2SJens Axboe 7914f6f0bd2SJens Axboe /* 792a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 793a4514ebdSJens Axboe * sync it. 7944f6f0bd2SJens Axboe */ 795a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 7964f6f0bd2SJens Axboe int err; 7974f6f0bd2SJens Axboe 7984f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 799a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8004f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8014f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8024f6f0bd2SJens Axboe 8034f6f0bd2SJens Axboe if (err) 8044f6f0bd2SJens Axboe ret = err; 8054f6f0bd2SJens Axboe } 806a4514ebdSJens Axboe } 8074f6f0bd2SJens Axboe 8084f6f0bd2SJens Axboe return ret; 8095274f052SJens Axboe } 8105274f052SJens Axboe 811059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 812059a8f37SJens Axboe 81383f9135bSJens Axboe /** 81483f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 81583f9135bSJens Axboe * @inode: pipe inode 81683f9135bSJens Axboe * @out: socket to write to 81783f9135bSJens Axboe * @len: number of bytes to splice 81883f9135bSJens Axboe * @flags: splice modifier flags 81983f9135bSJens Axboe * 82083f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 82183f9135bSJens Axboe * is involved. 82283f9135bSJens Axboe * 82383f9135bSJens Axboe */ 8243a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 825cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8265274f052SJens Axboe { 82700522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8285274f052SJens Axboe } 8295274f052SJens Axboe 830059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 831a0f06780SJeff Garzik 83283f9135bSJens Axboe /* 83383f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 83483f9135bSJens Axboe */ 8353a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 836cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8375274f052SJens Axboe { 8385274f052SJens Axboe int ret; 8395274f052SJens Axboe 84049570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 8415274f052SJens Axboe return -EINVAL; 8425274f052SJens Axboe 84349570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 8445274f052SJens Axboe return -EBADF; 8455274f052SJens Axboe 846cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 8475274f052SJens Axboe if (unlikely(ret < 0)) 8485274f052SJens Axboe return ret; 8495274f052SJens Axboe 850cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 8515274f052SJens Axboe } 8525274f052SJens Axboe 85383f9135bSJens Axboe /* 85483f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 85583f9135bSJens Axboe */ 856cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 857cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 858cbb7e577SJens Axboe unsigned int flags) 8595274f052SJens Axboe { 860cbb7e577SJens Axboe loff_t isize, left; 8615274f052SJens Axboe int ret; 8625274f052SJens Axboe 86349570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 8645274f052SJens Axboe return -EINVAL; 8655274f052SJens Axboe 86649570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8675274f052SJens Axboe return -EBADF; 8685274f052SJens Axboe 869cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 8705274f052SJens Axboe if (unlikely(ret < 0)) 8715274f052SJens Axboe return ret; 8725274f052SJens Axboe 8735274f052SJens Axboe isize = i_size_read(in->f_mapping->host); 874cbb7e577SJens Axboe if (unlikely(*ppos >= isize)) 8755274f052SJens Axboe return 0; 8765274f052SJens Axboe 877cbb7e577SJens Axboe left = isize - *ppos; 87849570e9bSJens Axboe if (unlikely(left < len)) 8795274f052SJens Axboe len = left; 8805274f052SJens Axboe 881cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 8825274f052SJens Axboe } 8835274f052SJens Axboe 884cbb7e577SJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 885cbb7e577SJens Axboe size_t len, unsigned int flags) 886b92ce558SJens Axboe { 887b92ce558SJens Axboe struct pipe_inode_info *pipe; 888b92ce558SJens Axboe long ret, bytes; 889cbb7e577SJens Axboe loff_t out_off; 890b92ce558SJens Axboe umode_t i_mode; 891b92ce558SJens Axboe int i; 892b92ce558SJens Axboe 893b92ce558SJens Axboe /* 894b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 895b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 896b92ce558SJens Axboe * piped splicing for that! 897b92ce558SJens Axboe */ 898b92ce558SJens Axboe i_mode = in->f_dentry->d_inode->i_mode; 899b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 900b92ce558SJens Axboe return -EINVAL; 901b92ce558SJens Axboe 902b92ce558SJens Axboe /* 903b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 904b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 905b92ce558SJens Axboe */ 906b92ce558SJens Axboe pipe = current->splice_pipe; 90749570e9bSJens Axboe if (unlikely(!pipe)) { 908b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 909b92ce558SJens Axboe if (!pipe) 910b92ce558SJens Axboe return -ENOMEM; 911b92ce558SJens Axboe 912b92ce558SJens Axboe /* 913b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 91400522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 915b92ce558SJens Axboe * PIPE_READERS appropriately. 916b92ce558SJens Axboe */ 917b92ce558SJens Axboe pipe->readers = 1; 918b92ce558SJens Axboe 919b92ce558SJens Axboe current->splice_pipe = pipe; 920b92ce558SJens Axboe } 921b92ce558SJens Axboe 922b92ce558SJens Axboe /* 92373d62d83SIngo Molnar * Do the splice. 924b92ce558SJens Axboe */ 925b92ce558SJens Axboe ret = 0; 926b92ce558SJens Axboe bytes = 0; 927cbb7e577SJens Axboe out_off = 0; 928b92ce558SJens Axboe 929b92ce558SJens Axboe while (len) { 930b92ce558SJens Axboe size_t read_len, max_read_len; 931b92ce558SJens Axboe 932b92ce558SJens Axboe /* 933b92ce558SJens Axboe * Do at most PIPE_BUFFERS pages worth of transfer: 934b92ce558SJens Axboe */ 935b92ce558SJens Axboe max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); 936b92ce558SJens Axboe 937cbb7e577SJens Axboe ret = do_splice_to(in, ppos, pipe, max_read_len, flags); 938b92ce558SJens Axboe if (unlikely(ret < 0)) 939b92ce558SJens Axboe goto out_release; 940b92ce558SJens Axboe 941b92ce558SJens Axboe read_len = ret; 942b92ce558SJens Axboe 943b92ce558SJens Axboe /* 944b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 945b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 946b92ce558SJens Axboe * could get stuck data in the internal pipe: 947b92ce558SJens Axboe */ 948cbb7e577SJens Axboe ret = do_splice_from(pipe, out, &out_off, read_len, 949b92ce558SJens Axboe flags & ~SPLICE_F_NONBLOCK); 950b92ce558SJens Axboe if (unlikely(ret < 0)) 951b92ce558SJens Axboe goto out_release; 952b92ce558SJens Axboe 953b92ce558SJens Axboe bytes += ret; 954b92ce558SJens Axboe len -= ret; 955b92ce558SJens Axboe 956b92ce558SJens Axboe /* 957b92ce558SJens Axboe * In nonblocking mode, if we got back a short read then 958b92ce558SJens Axboe * that was due to either an IO error or due to the 959b92ce558SJens Axboe * pagecache entry not being there. In the IO error case 960b92ce558SJens Axboe * the _next_ splice attempt will produce a clean IO error 961b92ce558SJens Axboe * return value (not a short read), so in both cases it's 962b92ce558SJens Axboe * correct to break out of the loop here: 963b92ce558SJens Axboe */ 964b92ce558SJens Axboe if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) 965b92ce558SJens Axboe break; 966b92ce558SJens Axboe } 967b92ce558SJens Axboe 968b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 969b92ce558SJens Axboe 970b92ce558SJens Axboe return bytes; 971b92ce558SJens Axboe 972b92ce558SJens Axboe out_release: 973b92ce558SJens Axboe /* 974b92ce558SJens Axboe * If we did an incomplete transfer we must release 975b92ce558SJens Axboe * the pipe buffers in question: 976b92ce558SJens Axboe */ 977b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 978b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 979b92ce558SJens Axboe 980b92ce558SJens Axboe if (buf->ops) { 981b92ce558SJens Axboe buf->ops->release(pipe, buf); 982b92ce558SJens Axboe buf->ops = NULL; 983b92ce558SJens Axboe } 984b92ce558SJens Axboe } 985b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 986b92ce558SJens Axboe 987b92ce558SJens Axboe /* 988b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 989b92ce558SJens Axboe */ 990b92ce558SJens Axboe if (bytes > 0) 991b92ce558SJens Axboe return bytes; 992b92ce558SJens Axboe 993b92ce558SJens Axboe return ret; 994b92ce558SJens Axboe } 995b92ce558SJens Axboe 996b92ce558SJens Axboe EXPORT_SYMBOL(do_splice_direct); 997b92ce558SJens Axboe 99883f9135bSJens Axboe /* 99983f9135bSJens Axboe * Determine where to splice to/from. 100083f9135bSJens Axboe */ 1001529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1002529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1003529565dcSIngo Molnar size_t len, unsigned int flags) 10045274f052SJens Axboe { 10053a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1006cbb7e577SJens Axboe loff_t offset, *off; 1007a4514ebdSJens Axboe long ret; 10085274f052SJens Axboe 10093a326a2cSIngo Molnar pipe = in->f_dentry->d_inode->i_pipe; 1010529565dcSIngo Molnar if (pipe) { 1011529565dcSIngo Molnar if (off_in) 1012529565dcSIngo Molnar return -ESPIPE; 1013b92ce558SJens Axboe if (off_out) { 1014b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1015b92ce558SJens Axboe return -EINVAL; 1016cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1017b92ce558SJens Axboe return -EFAULT; 1018cbb7e577SJens Axboe off = &offset; 1019cbb7e577SJens Axboe } else 1020cbb7e577SJens Axboe off = &out->f_pos; 1021529565dcSIngo Molnar 1022a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1023a4514ebdSJens Axboe 1024a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1025a4514ebdSJens Axboe ret = -EFAULT; 1026a4514ebdSJens Axboe 1027a4514ebdSJens Axboe return ret; 1028529565dcSIngo Molnar } 10295274f052SJens Axboe 10303a326a2cSIngo Molnar pipe = out->f_dentry->d_inode->i_pipe; 1031529565dcSIngo Molnar if (pipe) { 1032529565dcSIngo Molnar if (off_out) 1033529565dcSIngo Molnar return -ESPIPE; 1034b92ce558SJens Axboe if (off_in) { 1035b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1036b92ce558SJens Axboe return -EINVAL; 1037cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1038b92ce558SJens Axboe return -EFAULT; 1039cbb7e577SJens Axboe off = &offset; 1040cbb7e577SJens Axboe } else 1041cbb7e577SJens Axboe off = &in->f_pos; 1042529565dcSIngo Molnar 1043a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1044a4514ebdSJens Axboe 1045a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1046a4514ebdSJens Axboe ret = -EFAULT; 1047a4514ebdSJens Axboe 1048a4514ebdSJens Axboe return ret; 1049529565dcSIngo Molnar } 10505274f052SJens Axboe 10515274f052SJens Axboe return -EINVAL; 10525274f052SJens Axboe } 10535274f052SJens Axboe 1054912d35f8SJens Axboe /* 1055912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1056912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1057912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1058912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1059912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1060912d35f8SJens Axboe */ 1061912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1062912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 1063912d35f8SJens Axboe struct partial_page *partial) 1064912d35f8SJens Axboe { 1065912d35f8SJens Axboe int buffers = 0, error = 0; 1066912d35f8SJens Axboe 1067912d35f8SJens Axboe /* 1068912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1069912d35f8SJens Axboe * across a "get_user()". 1070912d35f8SJens Axboe */ 1071912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1072912d35f8SJens Axboe 1073912d35f8SJens Axboe while (nr_vecs) { 1074912d35f8SJens Axboe unsigned long off, npages; 1075912d35f8SJens Axboe void __user *base; 1076912d35f8SJens Axboe size_t len; 1077912d35f8SJens Axboe int i; 1078912d35f8SJens Axboe 1079912d35f8SJens Axboe /* 1080912d35f8SJens Axboe * Get user address base and length for this iovec. 1081912d35f8SJens Axboe */ 1082912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1083912d35f8SJens Axboe if (unlikely(error)) 1084912d35f8SJens Axboe break; 1085912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1086912d35f8SJens Axboe if (unlikely(error)) 1087912d35f8SJens Axboe break; 1088912d35f8SJens Axboe 1089912d35f8SJens Axboe /* 1090912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1091912d35f8SJens Axboe */ 1092912d35f8SJens Axboe if (unlikely(!len)) 1093912d35f8SJens Axboe break; 1094912d35f8SJens Axboe error = -EFAULT; 1095912d35f8SJens Axboe if (unlikely(!base)) 1096912d35f8SJens Axboe break; 1097912d35f8SJens Axboe 1098912d35f8SJens Axboe /* 1099912d35f8SJens Axboe * Get this base offset and number of pages, then map 1100912d35f8SJens Axboe * in the user pages. 1101912d35f8SJens Axboe */ 1102912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 1103912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1104912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1105912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1106912d35f8SJens Axboe 1107912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1108912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1109912d35f8SJens Axboe &pages[buffers], NULL); 1110912d35f8SJens Axboe 1111912d35f8SJens Axboe if (unlikely(error <= 0)) 1112912d35f8SJens Axboe break; 1113912d35f8SJens Axboe 1114912d35f8SJens Axboe /* 1115912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1116912d35f8SJens Axboe */ 1117912d35f8SJens Axboe for (i = 0; i < error; i++) { 1118912d35f8SJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE) - off; 1119912d35f8SJens Axboe 1120912d35f8SJens Axboe partial[buffers].offset = off; 1121912d35f8SJens Axboe partial[buffers].len = plen; 1122912d35f8SJens Axboe 1123912d35f8SJens Axboe off = 0; 1124912d35f8SJens Axboe len -= plen; 1125912d35f8SJens Axboe buffers++; 1126912d35f8SJens Axboe } 1127912d35f8SJens Axboe 1128912d35f8SJens Axboe /* 1129912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1130912d35f8SJens Axboe * means we have to move some of this into a pipe to 1131912d35f8SJens Axboe * be able to continue. 1132912d35f8SJens Axboe */ 1133912d35f8SJens Axboe if (len) 1134912d35f8SJens Axboe break; 1135912d35f8SJens Axboe 1136912d35f8SJens Axboe /* 1137912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1138912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1139912d35f8SJens Axboe * room for. 1140912d35f8SJens Axboe */ 1141912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1142912d35f8SJens Axboe break; 1143912d35f8SJens Axboe 1144912d35f8SJens Axboe nr_vecs--; 1145912d35f8SJens Axboe iov++; 1146912d35f8SJens Axboe } 1147912d35f8SJens Axboe 1148912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1149912d35f8SJens Axboe 1150912d35f8SJens Axboe if (buffers) 1151912d35f8SJens Axboe return buffers; 1152912d35f8SJens Axboe 1153912d35f8SJens Axboe return error; 1154912d35f8SJens Axboe } 1155912d35f8SJens Axboe 1156912d35f8SJens Axboe /* 1157912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1158912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1159912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1160912d35f8SJens Axboe * 1161912d35f8SJens Axboe * Note that vmsplice only supports splicing _from_ user memory to a pipe, 1162912d35f8SJens Axboe * not the other way around. Splicing from user memory is a simple operation 1163912d35f8SJens Axboe * that can be supported without any funky alignment restrictions or nasty 1164912d35f8SJens Axboe * vm tricks. We simply map in the user memory and fill them into a pipe. 1165912d35f8SJens Axboe * The reverse isn't quite as easy, though. There are two possible solutions 1166912d35f8SJens Axboe * for that: 1167912d35f8SJens Axboe * 1168912d35f8SJens Axboe * - memcpy() the data internally, at which point we might as well just 1169912d35f8SJens Axboe * do a regular read() on the buffer anyway. 1170912d35f8SJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 1171912d35f8SJens Axboe * has restriction limitations on both ends of the pipe). 1172912d35f8SJens Axboe * 1173912d35f8SJens Axboe * Alas, it isn't here. 1174912d35f8SJens Axboe * 1175912d35f8SJens Axboe */ 1176912d35f8SJens Axboe static long do_vmsplice(struct file *file, const struct iovec __user *iov, 1177912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1178912d35f8SJens Axboe { 1179912d35f8SJens Axboe struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; 1180912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1181912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1182912d35f8SJens Axboe struct splice_pipe_desc spd = { 1183912d35f8SJens Axboe .pages = pages, 1184912d35f8SJens Axboe .partial = partial, 1185912d35f8SJens Axboe .flags = flags, 1186912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1187912d35f8SJens Axboe }; 1188912d35f8SJens Axboe 1189912d35f8SJens Axboe if (unlikely(!pipe)) 1190912d35f8SJens Axboe return -EBADF; 1191912d35f8SJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 1192912d35f8SJens Axboe return -EINVAL; 1193912d35f8SJens Axboe else if (unlikely(!nr_segs)) 1194912d35f8SJens Axboe return 0; 1195912d35f8SJens Axboe 1196912d35f8SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial); 1197912d35f8SJens Axboe if (spd.nr_pages <= 0) 1198912d35f8SJens Axboe return spd.nr_pages; 1199912d35f8SJens Axboe 120000522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1201912d35f8SJens Axboe } 1202912d35f8SJens Axboe 1203912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1204912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1205912d35f8SJens Axboe { 1206912d35f8SJens Axboe struct file *file; 1207912d35f8SJens Axboe long error; 1208912d35f8SJens Axboe int fput; 1209912d35f8SJens Axboe 1210912d35f8SJens Axboe error = -EBADF; 1211912d35f8SJens Axboe file = fget_light(fd, &fput); 1212912d35f8SJens Axboe if (file) { 1213912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 1214912d35f8SJens Axboe error = do_vmsplice(file, iov, nr_segs, flags); 1215912d35f8SJens Axboe 1216912d35f8SJens Axboe fput_light(file, fput); 1217912d35f8SJens Axboe } 1218912d35f8SJens Axboe 1219912d35f8SJens Axboe return error; 1220912d35f8SJens Axboe } 1221912d35f8SJens Axboe 1222529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1223529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1224529565dcSIngo Molnar size_t len, unsigned int flags) 12255274f052SJens Axboe { 12265274f052SJens Axboe long error; 12275274f052SJens Axboe struct file *in, *out; 12285274f052SJens Axboe int fput_in, fput_out; 12295274f052SJens Axboe 12305274f052SJens Axboe if (unlikely(!len)) 12315274f052SJens Axboe return 0; 12325274f052SJens Axboe 12335274f052SJens Axboe error = -EBADF; 1234529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 12355274f052SJens Axboe if (in) { 12365274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1237529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 12385274f052SJens Axboe if (out) { 12395274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1240529565dcSIngo Molnar error = do_splice(in, off_in, 1241529565dcSIngo Molnar out, off_out, 1242529565dcSIngo Molnar len, flags); 12435274f052SJens Axboe fput_light(out, fput_out); 12445274f052SJens Axboe } 12455274f052SJens Axboe } 12465274f052SJens Axboe 12475274f052SJens Axboe fput_light(in, fput_in); 12485274f052SJens Axboe } 12495274f052SJens Axboe 12505274f052SJens Axboe return error; 12515274f052SJens Axboe } 125270524490SJens Axboe 125370524490SJens Axboe /* 125470524490SJens Axboe * Link contents of ipipe to opipe. 125570524490SJens Axboe */ 125670524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 125770524490SJens Axboe struct pipe_inode_info *opipe, 125870524490SJens Axboe size_t len, unsigned int flags) 125970524490SJens Axboe { 126070524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 12612a27250eSJens Axboe int ret, do_wakeup, i, ipipe_first; 12622a27250eSJens Axboe 12632a27250eSJens Axboe ret = do_wakeup = ipipe_first = 0; 126470524490SJens Axboe 126570524490SJens Axboe /* 126670524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 126770524490SJens Axboe * grabbing by inode address. Otherwise two different processes 126870524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 126970524490SJens Axboe */ 127070524490SJens Axboe if (ipipe->inode < opipe->inode) { 12712a27250eSJens Axboe ipipe_first = 1; 127270524490SJens Axboe mutex_lock(&ipipe->inode->i_mutex); 127370524490SJens Axboe mutex_lock(&opipe->inode->i_mutex); 127470524490SJens Axboe } else { 127570524490SJens Axboe mutex_lock(&opipe->inode->i_mutex); 127670524490SJens Axboe mutex_lock(&ipipe->inode->i_mutex); 127770524490SJens Axboe } 127870524490SJens Axboe 127970524490SJens Axboe for (i = 0;; i++) { 128070524490SJens Axboe if (!opipe->readers) { 128170524490SJens Axboe send_sig(SIGPIPE, current, 0); 128270524490SJens Axboe if (!ret) 128370524490SJens Axboe ret = -EPIPE; 128470524490SJens Axboe break; 128570524490SJens Axboe } 128670524490SJens Axboe if (ipipe->nrbufs - i) { 128770524490SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 128870524490SJens Axboe 128970524490SJens Axboe /* 129070524490SJens Axboe * If we have room, fill this buffer 129170524490SJens Axboe */ 129270524490SJens Axboe if (opipe->nrbufs < PIPE_BUFFERS) { 129370524490SJens Axboe int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 129470524490SJens Axboe 129570524490SJens Axboe /* 129670524490SJens Axboe * Get a reference to this pipe buffer, 129770524490SJens Axboe * so we can copy the contents over. 129870524490SJens Axboe */ 129970524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 130070524490SJens Axboe 130170524490SJens Axboe obuf = opipe->bufs + nbuf; 130270524490SJens Axboe *obuf = *ibuf; 130370524490SJens Axboe 130470524490SJens Axboe if (obuf->len > len) 130570524490SJens Axboe obuf->len = len; 130670524490SJens Axboe 130770524490SJens Axboe opipe->nrbufs++; 130870524490SJens Axboe do_wakeup = 1; 130970524490SJens Axboe ret += obuf->len; 131070524490SJens Axboe len -= obuf->len; 131170524490SJens Axboe 131270524490SJens Axboe if (!len) 131370524490SJens Axboe break; 131470524490SJens Axboe if (opipe->nrbufs < PIPE_BUFFERS) 131570524490SJens Axboe continue; 131670524490SJens Axboe } 131770524490SJens Axboe 131870524490SJens Axboe /* 131970524490SJens Axboe * We have input available, but no output room. 13202a27250eSJens Axboe * If we already copied data, return that. If we 13212a27250eSJens Axboe * need to drop the opipe lock, it must be ordered 13222a27250eSJens Axboe * last to avoid deadlocks. 132370524490SJens Axboe */ 13242a27250eSJens Axboe if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { 132570524490SJens Axboe if (!ret) 132670524490SJens Axboe ret = -EAGAIN; 132770524490SJens Axboe break; 132870524490SJens Axboe } 132970524490SJens Axboe if (signal_pending(current)) { 133070524490SJens Axboe if (!ret) 133170524490SJens Axboe ret = -ERESTARTSYS; 133270524490SJens Axboe break; 133370524490SJens Axboe } 133470524490SJens Axboe if (do_wakeup) { 133570524490SJens Axboe smp_mb(); 133670524490SJens Axboe if (waitqueue_active(&opipe->wait)) 133770524490SJens Axboe wake_up_interruptible(&opipe->wait); 133870524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 133970524490SJens Axboe do_wakeup = 0; 134070524490SJens Axboe } 134170524490SJens Axboe 134270524490SJens Axboe opipe->waiting_writers++; 134370524490SJens Axboe pipe_wait(opipe); 134470524490SJens Axboe opipe->waiting_writers--; 134570524490SJens Axboe continue; 134670524490SJens Axboe } 134770524490SJens Axboe 134870524490SJens Axboe /* 134970524490SJens Axboe * No input buffers, do the usual checks for available 135070524490SJens Axboe * writers and blocking and wait if necessary 135170524490SJens Axboe */ 135270524490SJens Axboe if (!ipipe->writers) 135370524490SJens Axboe break; 135470524490SJens Axboe if (!ipipe->waiting_writers) { 135570524490SJens Axboe if (ret) 135670524490SJens Axboe break; 135770524490SJens Axboe } 13582a27250eSJens Axboe /* 13592a27250eSJens Axboe * pipe_wait() drops the ipipe mutex. To avoid deadlocks 13602a27250eSJens Axboe * with another process, we can only safely do that if 13612a27250eSJens Axboe * the ipipe lock is ordered last. 13622a27250eSJens Axboe */ 13632a27250eSJens Axboe if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { 136470524490SJens Axboe if (!ret) 136570524490SJens Axboe ret = -EAGAIN; 136670524490SJens Axboe break; 136770524490SJens Axboe } 136870524490SJens Axboe if (signal_pending(current)) { 136970524490SJens Axboe if (!ret) 137070524490SJens Axboe ret = -ERESTARTSYS; 137170524490SJens Axboe break; 137270524490SJens Axboe } 137370524490SJens Axboe 137470524490SJens Axboe if (waitqueue_active(&ipipe->wait)) 137570524490SJens Axboe wake_up_interruptible_sync(&ipipe->wait); 137670524490SJens Axboe kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); 137770524490SJens Axboe 137870524490SJens Axboe pipe_wait(ipipe); 137970524490SJens Axboe } 138070524490SJens Axboe 138170524490SJens Axboe mutex_unlock(&ipipe->inode->i_mutex); 138270524490SJens Axboe mutex_unlock(&opipe->inode->i_mutex); 138370524490SJens Axboe 138470524490SJens Axboe if (do_wakeup) { 138570524490SJens Axboe smp_mb(); 138670524490SJens Axboe if (waitqueue_active(&opipe->wait)) 138770524490SJens Axboe wake_up_interruptible(&opipe->wait); 138870524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 138970524490SJens Axboe } 139070524490SJens Axboe 139170524490SJens Axboe return ret; 139270524490SJens Axboe } 139370524490SJens Axboe 139470524490SJens Axboe /* 139570524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 139670524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 139770524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 139870524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 139970524490SJens Axboe */ 140070524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 140170524490SJens Axboe unsigned int flags) 140270524490SJens Axboe { 140370524490SJens Axboe struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; 140470524490SJens Axboe struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; 140570524490SJens Axboe 140670524490SJens Axboe /* 140770524490SJens Axboe * Link ipipe to the two output pipes, consuming as we go along. 140870524490SJens Axboe */ 140970524490SJens Axboe if (ipipe && opipe) 141070524490SJens Axboe return link_pipe(ipipe, opipe, len, flags); 141170524490SJens Axboe 141270524490SJens Axboe return -EINVAL; 141370524490SJens Axboe } 141470524490SJens Axboe 141570524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 141670524490SJens Axboe { 141770524490SJens Axboe struct file *in; 141870524490SJens Axboe int error, fput_in; 141970524490SJens Axboe 142070524490SJens Axboe if (unlikely(!len)) 142170524490SJens Axboe return 0; 142270524490SJens Axboe 142370524490SJens Axboe error = -EBADF; 142470524490SJens Axboe in = fget_light(fdin, &fput_in); 142570524490SJens Axboe if (in) { 142670524490SJens Axboe if (in->f_mode & FMODE_READ) { 142770524490SJens Axboe int fput_out; 142870524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 142970524490SJens Axboe 143070524490SJens Axboe if (out) { 143170524490SJens Axboe if (out->f_mode & FMODE_WRITE) 143270524490SJens Axboe error = do_tee(in, out, len, flags); 143370524490SJens Axboe fput_light(out, fput_out); 143470524490SJens Axboe } 143570524490SJens Axboe } 143670524490SJens Axboe fput_light(in, fput_in); 143770524490SJens Axboe } 143870524490SJens Axboe 143970524490SJens Axboe return error; 144070524490SJens Axboe } 1441