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 * 150fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 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> 23d6b29d7cSJens Axboe #include <linux/splice.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 3283f9135bSJens Axboe /* 3383f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3483f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 3583f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 3683f9135bSJens Axboe * attempt to reuse this page for another destination. 3783f9135bSJens Axboe */ 3876ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 395abc97aaSJens Axboe struct pipe_buffer *buf) 405abc97aaSJens Axboe { 415abc97aaSJens Axboe struct page *page = buf->page; 429e94cd4fSJens Axboe struct address_space *mapping; 435abc97aaSJens Axboe 449e0267c2SJens Axboe lock_page(page); 459e0267c2SJens Axboe 469e94cd4fSJens Axboe mapping = page_mapping(page); 479e94cd4fSJens Axboe if (mapping) { 485abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 495abc97aaSJens Axboe 50ad8d6f0aSJens Axboe /* 519e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 529e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 539e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 549e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 559e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 569e94cd4fSJens Axboe * ensues. 57ad8d6f0aSJens Axboe */ 58ad8d6f0aSJens Axboe wait_on_page_writeback(page); 59ad8d6f0aSJens Axboe 604f6f0bd2SJens Axboe if (PagePrivate(page)) 612ae88149SNick Piggin try_to_release_page(page, GFP_KERNEL); 624f6f0bd2SJens Axboe 639e94cd4fSJens Axboe /* 649e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 659e94cd4fSJens Axboe * and return good. 669e94cd4fSJens Axboe */ 679e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 681432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 695abc97aaSJens Axboe return 0; 705abc97aaSJens Axboe } 719e94cd4fSJens Axboe } 729e94cd4fSJens Axboe 739e94cd4fSJens Axboe /* 749e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 759e94cd4fSJens Axboe * address space, unlock and return failure. 769e94cd4fSJens Axboe */ 779e94cd4fSJens Axboe unlock_page(page); 789e94cd4fSJens Axboe return 1; 799e94cd4fSJens Axboe } 805abc97aaSJens Axboe 8176ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 825274f052SJens Axboe struct pipe_buffer *buf) 835274f052SJens Axboe { 845274f052SJens Axboe page_cache_release(buf->page); 851432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 865274f052SJens Axboe } 875274f052SJens Axboe 880845718dSJens Axboe /* 890845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 900845718dSJens Axboe * is a page cache page, IO may be in flight. 910845718dSJens Axboe */ 92cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 935274f052SJens Axboe struct pipe_buffer *buf) 945274f052SJens Axboe { 955274f052SJens Axboe struct page *page = buf->page; 9649d0b21bSJens Axboe int err; 975274f052SJens Axboe 985274f052SJens Axboe if (!PageUptodate(page)) { 9949d0b21bSJens Axboe lock_page(page); 1005274f052SJens Axboe 10149d0b21bSJens Axboe /* 10249d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10373d62d83SIngo Molnar * splice, if this is the first page. 10449d0b21bSJens Axboe */ 1055274f052SJens Axboe if (!page->mapping) { 10649d0b21bSJens Axboe err = -ENODATA; 10749d0b21bSJens Axboe goto error; 1085274f052SJens Axboe } 1095274f052SJens Axboe 11049d0b21bSJens Axboe /* 11173d62d83SIngo Molnar * Uh oh, read-error from disk. 11249d0b21bSJens Axboe */ 11349d0b21bSJens Axboe if (!PageUptodate(page)) { 11449d0b21bSJens Axboe err = -EIO; 11549d0b21bSJens Axboe goto error; 11649d0b21bSJens Axboe } 11749d0b21bSJens Axboe 11849d0b21bSJens Axboe /* 119f84d7519SJens Axboe * Page is ok afterall, we are done. 12049d0b21bSJens Axboe */ 12149d0b21bSJens Axboe unlock_page(page); 12249d0b21bSJens Axboe } 12349d0b21bSJens Axboe 124f84d7519SJens Axboe return 0; 12549d0b21bSJens Axboe error: 12649d0b21bSJens Axboe unlock_page(page); 127f84d7519SJens Axboe return err; 12870524490SJens Axboe } 12970524490SJens Axboe 130d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1315274f052SJens Axboe .can_merge = 0, 132f84d7519SJens Axboe .map = generic_pipe_buf_map, 133f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 134cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1355274f052SJens Axboe .release = page_cache_pipe_buf_release, 1365abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 137f84d7519SJens Axboe .get = generic_pipe_buf_get, 1385274f052SJens Axboe }; 1395274f052SJens Axboe 140912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 141912d35f8SJens Axboe struct pipe_buffer *buf) 142912d35f8SJens Axboe { 1437afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 144912d35f8SJens Axboe return 1; 1457afa6fd0SJens Axboe 1461432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 147330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 148912d35f8SJens Axboe } 149912d35f8SJens Axboe 150d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 151912d35f8SJens Axboe .can_merge = 0, 152f84d7519SJens Axboe .map = generic_pipe_buf_map, 153f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 154cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 155912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 156912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 157f84d7519SJens Axboe .get = generic_pipe_buf_get, 158912d35f8SJens Axboe }; 159912d35f8SJens Axboe 160932cc6d4SJens Axboe /** 161932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 162932cc6d4SJens Axboe * @pipe: pipe to fill 163932cc6d4SJens Axboe * @spd: data to fill 164932cc6d4SJens Axboe * 165932cc6d4SJens Axboe * Description: 166932cc6d4SJens Axboe * @spd contains a map of pages and len/offset tupples, a long with 167932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 168932cc6d4SJens Axboe * function will link that data to the pipe. 169932cc6d4SJens Axboe * 17083f9135bSJens Axboe */ 171d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 172912d35f8SJens Axboe struct splice_pipe_desc *spd) 1735274f052SJens Axboe { 17400de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 175912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1765274f052SJens Axboe 1775274f052SJens Axboe ret = 0; 1785274f052SJens Axboe do_wakeup = 0; 179912d35f8SJens Axboe page_nr = 0; 1805274f052SJens Axboe 1813a326a2cSIngo Molnar if (pipe->inode) 1823a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1835274f052SJens Axboe 1845274f052SJens Axboe for (;;) { 1853a326a2cSIngo Molnar if (!pipe->readers) { 1865274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1875274f052SJens Axboe if (!ret) 1885274f052SJens Axboe ret = -EPIPE; 1895274f052SJens Axboe break; 1905274f052SJens Axboe } 1915274f052SJens Axboe 1926f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1936f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1943a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1955274f052SJens Axboe 196912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 197912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 198912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 199497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 200912d35f8SJens Axboe buf->ops = spd->ops; 2017afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2027afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2037afa6fd0SJens Axboe 2046f767b04SJens Axboe pipe->nrbufs++; 205912d35f8SJens Axboe page_nr++; 206912d35f8SJens Axboe ret += buf->len; 207912d35f8SJens Axboe 2086f767b04SJens Axboe if (pipe->inode) 2095274f052SJens Axboe do_wakeup = 1; 2105274f052SJens Axboe 211912d35f8SJens Axboe if (!--spd->nr_pages) 2125274f052SJens Axboe break; 2136f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2145274f052SJens Axboe continue; 2155274f052SJens Axboe 2165274f052SJens Axboe break; 2175274f052SJens Axboe } 2185274f052SJens Axboe 219912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22029e35094SLinus Torvalds if (!ret) 22129e35094SLinus Torvalds ret = -EAGAIN; 22229e35094SLinus Torvalds break; 22329e35094SLinus Torvalds } 22429e35094SLinus Torvalds 2255274f052SJens Axboe if (signal_pending(current)) { 2265274f052SJens Axboe if (!ret) 2275274f052SJens Axboe ret = -ERESTARTSYS; 2285274f052SJens Axboe break; 2295274f052SJens Axboe } 2305274f052SJens Axboe 2315274f052SJens Axboe if (do_wakeup) { 232c0bd1f65SJens Axboe smp_mb(); 2333a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2343a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2353a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2365274f052SJens Axboe do_wakeup = 0; 2375274f052SJens Axboe } 2385274f052SJens Axboe 2393a326a2cSIngo Molnar pipe->waiting_writers++; 2403a326a2cSIngo Molnar pipe_wait(pipe); 2413a326a2cSIngo Molnar pipe->waiting_writers--; 2425274f052SJens Axboe } 2435274f052SJens Axboe 24402676e5aSJens Axboe if (pipe->inode) { 2453a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2465274f052SJens Axboe 2475274f052SJens Axboe if (do_wakeup) { 248c0bd1f65SJens Axboe smp_mb(); 2493a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2503a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2513a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2525274f052SJens Axboe } 25302676e5aSJens Axboe } 2545274f052SJens Axboe 25500de00bdSJens Axboe while (page_nr < spd_pages) 256912d35f8SJens Axboe page_cache_release(spd->pages[page_nr++]); 2575274f052SJens Axboe 2585274f052SJens Axboe return ret; 2595274f052SJens Axboe } 2605274f052SJens Axboe 2613a326a2cSIngo Molnar static int 262cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 263cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 264cbb7e577SJens Axboe unsigned int flags) 2655274f052SJens Axboe { 2665274f052SJens Axboe struct address_space *mapping = in->f_mapping; 267912d35f8SJens Axboe unsigned int loff, nr_pages; 26816c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 269912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2705274f052SJens Axboe struct page *page; 27191ad66efSJens Axboe pgoff_t index, end_index; 27291ad66efSJens Axboe loff_t isize; 273eb20796bSJens Axboe int error, page_nr; 274912d35f8SJens Axboe struct splice_pipe_desc spd = { 275912d35f8SJens Axboe .pages = pages, 276912d35f8SJens Axboe .partial = partial, 277912d35f8SJens Axboe .flags = flags, 278912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 279912d35f8SJens Axboe }; 2805274f052SJens Axboe 281cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 282912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 283912d35f8SJens Axboe nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2845274f052SJens Axboe 2855274f052SJens Axboe if (nr_pages > PIPE_BUFFERS) 2865274f052SJens Axboe nr_pages = PIPE_BUFFERS; 2875274f052SJens Axboe 2885274f052SJens Axboe /* 28986aa5ac5SJens Axboe * Don't try to 2nd guess the read-ahead logic, call into 29086aa5ac5SJens Axboe * page_cache_readahead() like the page cache reads would do. 2915274f052SJens Axboe */ 292eb645a24SJens Axboe page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); 2935274f052SJens Axboe 2945274f052SJens Axboe /* 295eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29682aa5d61SJens Axboe */ 297eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 298eb20796bSJens Axboe 2995274f052SJens Axboe /* 300eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 301932cc6d4SJens Axboe * allocate the rest and fill in the holes. 302eb20796bSJens Axboe */ 303932cc6d4SJens Axboe error = 0; 304eb20796bSJens Axboe index += spd.nr_pages; 305eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 306eb20796bSJens Axboe /* 307eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 308eb20796bSJens Axboe * the first hole. 3095274f052SJens Axboe */ 3107480a904SJens Axboe page = find_get_page(mapping, index); 3117480a904SJens Axboe if (!page) { 3127480a904SJens Axboe /* 313e27dedd8SJens Axboe * Make sure the read-ahead engine is notified 314e27dedd8SJens Axboe * about this failure. 315e27dedd8SJens Axboe */ 316e27dedd8SJens Axboe handle_ra_miss(mapping, &in->f_ra, index); 317e27dedd8SJens Axboe 318e27dedd8SJens Axboe /* 319eb20796bSJens Axboe * page didn't exist, allocate one. 3207480a904SJens Axboe */ 3217480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3225274f052SJens Axboe if (!page) 3235274f052SJens Axboe break; 3245274f052SJens Axboe 3257480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3262ae88149SNick Piggin GFP_KERNEL); 3275274f052SJens Axboe if (unlikely(error)) { 3285274f052SJens Axboe page_cache_release(page); 329a0548871SJens Axboe if (error == -EEXIST) 330a0548871SJens Axboe continue; 3315274f052SJens Axboe break; 3325274f052SJens Axboe } 333eb20796bSJens Axboe /* 334eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 335eb20796bSJens Axboe * to avoid convoluting the logic below even more. 336eb20796bSJens Axboe */ 337eb20796bSJens Axboe unlock_page(page); 3385274f052SJens Axboe } 3397480a904SJens Axboe 340eb20796bSJens Axboe pages[spd.nr_pages++] = page; 341eb20796bSJens Axboe index++; 342eb20796bSJens Axboe } 343eb20796bSJens Axboe 344eb20796bSJens Axboe /* 345eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 346eb20796bSJens Axboe * pages, fill in the partial map, etc. 347eb20796bSJens Axboe */ 348eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 349eb20796bSJens Axboe nr_pages = spd.nr_pages; 350eb20796bSJens Axboe spd.nr_pages = 0; 351eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 352eb20796bSJens Axboe unsigned int this_len; 353eb20796bSJens Axboe 354eb20796bSJens Axboe if (!len) 355eb20796bSJens Axboe break; 356eb20796bSJens Axboe 357eb20796bSJens Axboe /* 358eb20796bSJens Axboe * this_len is the max we'll use from this page 359eb20796bSJens Axboe */ 360eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 361eb20796bSJens Axboe page = pages[page_nr]; 362eb20796bSJens Axboe 3637480a904SJens Axboe /* 3647480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3657480a904SJens Axboe */ 3667480a904SJens Axboe if (!PageUptodate(page)) { 367c4f895cbSJens Axboe /* 368c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 369c4f895cbSJens Axboe * for an in-flight io page 370c4f895cbSJens Axboe */ 3719ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3729ae9d68cSFengguang Wu if (TestSetPageLocked(page)) 373c4f895cbSJens Axboe break; 3749ae9d68cSFengguang Wu } else 3757480a904SJens Axboe lock_page(page); 3767480a904SJens Axboe 3777480a904SJens Axboe /* 3787480a904SJens Axboe * page was truncated, stop here. if this isn't the 3797480a904SJens Axboe * first page, we'll just complete what we already 3807480a904SJens Axboe * added 3817480a904SJens Axboe */ 3827480a904SJens Axboe if (!page->mapping) { 3837480a904SJens Axboe unlock_page(page); 3847480a904SJens Axboe break; 3857480a904SJens Axboe } 3867480a904SJens Axboe /* 3877480a904SJens Axboe * page was already under io and is now done, great 3887480a904SJens Axboe */ 3897480a904SJens Axboe if (PageUptodate(page)) { 3907480a904SJens Axboe unlock_page(page); 3917480a904SJens Axboe goto fill_it; 3927480a904SJens Axboe } 3937480a904SJens Axboe 3947480a904SJens Axboe /* 3957480a904SJens Axboe * need to read in the page 3967480a904SJens Axboe */ 3977480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 3987480a904SJens Axboe if (unlikely(error)) { 399eb20796bSJens Axboe /* 400eb20796bSJens Axboe * We really should re-lookup the page here, 401eb20796bSJens Axboe * but it complicates things a lot. Instead 402eb20796bSJens Axboe * lets just do what we already stored, and 403eb20796bSJens Axboe * we'll get it the next time we are called. 404eb20796bSJens Axboe */ 4057480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 406eb20796bSJens Axboe error = 0; 407eb20796bSJens Axboe 4087480a904SJens Axboe break; 4097480a904SJens Axboe } 410620a324bSJens Axboe } 411620a324bSJens Axboe fill_it: 41291ad66efSJens Axboe /* 413620a324bSJens Axboe * i_size must be checked after PageUptodate. 41491ad66efSJens Axboe */ 41591ad66efSJens Axboe isize = i_size_read(mapping->host); 41691ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 417eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 41891ad66efSJens Axboe break; 41991ad66efSJens Axboe 42091ad66efSJens Axboe /* 42191ad66efSJens Axboe * if this is the last page, see if we need to shrink 42291ad66efSJens Axboe * the length and stop 42391ad66efSJens Axboe */ 42491ad66efSJens Axboe if (end_index == index) { 425475ecadeSHugh Dickins unsigned int plen; 426475ecadeSHugh Dickins 427475ecadeSHugh Dickins /* 428475ecadeSHugh Dickins * max good bytes in this page 429475ecadeSHugh Dickins */ 430475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 431475ecadeSHugh Dickins if (plen <= loff) 43291ad66efSJens Axboe break; 433475ecadeSHugh Dickins 43491ad66efSJens Axboe /* 43591ad66efSJens Axboe * force quit after adding this page 43691ad66efSJens Axboe */ 437475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 438eb20796bSJens Axboe len = this_len; 43991ad66efSJens Axboe } 440620a324bSJens Axboe 441eb20796bSJens Axboe partial[page_nr].offset = loff; 442eb20796bSJens Axboe partial[page_nr].len = this_len; 44382aa5d61SJens Axboe len -= this_len; 44491ad66efSJens Axboe loff = 0; 445eb20796bSJens Axboe spd.nr_pages++; 446eb20796bSJens Axboe index++; 4475274f052SJens Axboe } 4485274f052SJens Axboe 449eb20796bSJens Axboe /* 450475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 451eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 452eb20796bSJens Axboe */ 453eb20796bSJens Axboe while (page_nr < nr_pages) 454eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 455eb20796bSJens Axboe 456912d35f8SJens Axboe if (spd.nr_pages) 45700522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 45816c523ddSJens Axboe 4597480a904SJens Axboe return error; 4605274f052SJens Axboe } 4615274f052SJens Axboe 46283f9135bSJens Axboe /** 46383f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46483f9135bSJens Axboe * @in: file to splice from 465932cc6d4SJens Axboe * @ppos: position in @in 46683f9135bSJens Axboe * @pipe: pipe to splice to 46783f9135bSJens Axboe * @len: number of bytes to splice 46883f9135bSJens Axboe * @flags: splice modifier flags 46983f9135bSJens Axboe * 470932cc6d4SJens Axboe * Description: 471932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 472932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 473932cc6d4SJens Axboe * a readpage() hook. 474932cc6d4SJens Axboe * 47583f9135bSJens Axboe */ 476cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 477cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 478cbb7e577SJens Axboe unsigned int flags) 4795274f052SJens Axboe { 4805274f052SJens Axboe ssize_t spliced; 4815274f052SJens Axboe int ret; 482d366d398SJens Axboe loff_t isize, left; 483d366d398SJens Axboe 484d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 485d366d398SJens Axboe if (unlikely(*ppos >= isize)) 486d366d398SJens Axboe return 0; 487d366d398SJens Axboe 488d366d398SJens Axboe left = isize - *ppos; 489d366d398SJens Axboe if (unlikely(left < len)) 490d366d398SJens Axboe len = left; 4915274f052SJens Axboe 4925274f052SJens Axboe ret = 0; 4935274f052SJens Axboe spliced = 0; 4945274f052SJens Axboe while (len) { 495cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4965274f052SJens Axboe 497c4f895cbSJens Axboe if (ret < 0) 4985274f052SJens Axboe break; 499c4f895cbSJens Axboe else if (!ret) { 500c4f895cbSJens Axboe if (spliced) 501c4f895cbSJens Axboe break; 502c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 503c4f895cbSJens Axboe ret = -EAGAIN; 504c4f895cbSJens Axboe break; 505c4f895cbSJens Axboe } 506c4f895cbSJens Axboe } 5075274f052SJens Axboe 508cbb7e577SJens Axboe *ppos += ret; 5095274f052SJens Axboe len -= ret; 5105274f052SJens Axboe spliced += ret; 5115274f052SJens Axboe } 5125274f052SJens Axboe 5135274f052SJens Axboe if (spliced) 5145274f052SJens Axboe return spliced; 5155274f052SJens Axboe 5165274f052SJens Axboe return ret; 5175274f052SJens Axboe } 5185274f052SJens Axboe 519059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 520059a8f37SJens Axboe 5215274f052SJens Axboe /* 5224f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 523016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5245274f052SJens Axboe */ 52576ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5265274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5275274f052SJens Axboe { 5286a14b90bSJens Axboe struct file *file = sd->u.file; 5295274f052SJens Axboe loff_t pos = sd->pos; 530f84d7519SJens Axboe int ret, more; 5315274f052SJens Axboe 532cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 533f84d7519SJens Axboe if (!ret) { 534b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5355274f052SJens Axboe 536f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 537f84d7519SJens Axboe sd->len, &pos, more); 538f84d7519SJens Axboe } 5395274f052SJens Axboe 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 */ 56376ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5645274f052SJens Axboe struct splice_desc *sd) 5655274f052SJens Axboe { 5666a14b90bSJens Axboe struct file *file = sd->u.file; 5675274f052SJens Axboe struct address_space *mapping = file->f_mapping; 568016b661eSJens Axboe unsigned int offset, this_len; 5695274f052SJens Axboe struct page *page; 5705274f052SJens Axboe pgoff_t index; 5713e7ee3e7SJens Axboe int ret; 5725274f052SJens Axboe 5735274f052SJens Axboe /* 57449d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5755274f052SJens Axboe */ 576cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 577f84d7519SJens Axboe if (unlikely(ret)) 578f84d7519SJens Axboe return ret; 5795274f052SJens Axboe 5805274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5815274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5825274f052SJens Axboe 583016b661eSJens Axboe this_len = sd->len; 584016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 585016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 586016b661eSJens Axboe 5875274f052SJens Axboe find_page: 5889e0267c2SJens Axboe page = find_lock_page(mapping, index); 5899e0267c2SJens Axboe if (!page) { 5905274f052SJens Axboe ret = -ENOMEM; 5919e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5929e0267c2SJens Axboe if (unlikely(!page)) 593e6e80f29SJens Axboe goto out_ret; 5945274f052SJens Axboe 5955274f052SJens Axboe /* 5969e0267c2SJens Axboe * This will also lock the page 5979e0267c2SJens Axboe */ 5989e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 5992ae88149SNick Piggin GFP_KERNEL); 6009e0267c2SJens Axboe if (unlikely(ret)) 6019e0267c2SJens Axboe goto out; 6029e0267c2SJens Axboe } 6039e0267c2SJens Axboe 604016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 605bfc4ee39SJens Axboe if (unlikely(ret)) { 606bfc4ee39SJens Axboe loff_t isize = i_size_read(mapping->host); 607bfc4ee39SJens Axboe 608bfc4ee39SJens Axboe if (ret != AOP_TRUNCATED_PAGE) 609bfc4ee39SJens Axboe unlock_page(page); 6104f6f0bd2SJens Axboe page_cache_release(page); 611bfc4ee39SJens Axboe if (ret == AOP_TRUNCATED_PAGE) 6124f6f0bd2SJens Axboe goto find_page; 613bfc4ee39SJens Axboe 614bfc4ee39SJens Axboe /* 615bfc4ee39SJens Axboe * prepare_write() may have instantiated a few blocks 616bfc4ee39SJens Axboe * outside i_size. Trim these off again. 617bfc4ee39SJens Axboe */ 618bfc4ee39SJens Axboe if (sd->pos + this_len > isize) 619bfc4ee39SJens Axboe vmtruncate(mapping->host, isize); 620bfc4ee39SJens Axboe 621e6e80f29SJens Axboe goto out_ret; 622bfc4ee39SJens Axboe } 6235274f052SJens Axboe 6240568b409SJens Axboe if (buf->page != page) { 625f84d7519SJens Axboe /* 626f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 627f84d7519SJens Axboe */ 62876ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 629f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 6305abc97aaSJens Axboe 631016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6325274f052SJens Axboe flush_dcache_page(page); 633f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 63476ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6355abc97aaSJens Axboe } 6365274f052SJens Axboe 637016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 638d9993c37SDmitriy Monakhov if (ret) { 639d9993c37SDmitriy Monakhov if (ret == AOP_TRUNCATED_PAGE) { 640d9993c37SDmitriy Monakhov page_cache_release(page); 641d9993c37SDmitriy Monakhov goto find_page; 642d9993c37SDmitriy Monakhov } 643d9993c37SDmitriy Monakhov if (ret < 0) 644d9993c37SDmitriy Monakhov goto out; 645d9993c37SDmitriy Monakhov /* 646d9993c37SDmitriy Monakhov * Partial write has happened, so 'ret' already initialized by 647d9993c37SDmitriy Monakhov * number of bytes written, Where is nothing we have to do here. 648d9993c37SDmitriy Monakhov */ 649d9993c37SDmitriy Monakhov } else 650d9993c37SDmitriy Monakhov ret = this_len; 651016b661eSJens Axboe /* 6520568b409SJens Axboe * Return the number of bytes written and mark page as 6530568b409SJens Axboe * accessed, we are now done! 654016b661eSJens Axboe */ 655c7f21e4fSJens Axboe mark_page_accessed(page); 6560568b409SJens Axboe out: 6570568b409SJens Axboe page_cache_release(page); 6584f6f0bd2SJens Axboe unlock_page(page); 659e6e80f29SJens Axboe out_ret: 6605274f052SJens Axboe return ret; 6615274f052SJens Axboe } 6625274f052SJens Axboe 663932cc6d4SJens Axboe /** 664932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 665932cc6d4SJens Axboe * @pipe: pipe to splice from 666932cc6d4SJens Axboe * @sd: information to @actor 667932cc6d4SJens Axboe * @actor: handler that splices the data 668932cc6d4SJens Axboe * 669932cc6d4SJens Axboe * Description: 670932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 671932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 672932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 673932cc6d4SJens Axboe * pipe_to_user. 674932cc6d4SJens Axboe * 67583f9135bSJens Axboe */ 676c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 677c66ab6faSJens Axboe splice_actor *actor) 6785274f052SJens Axboe { 6795274f052SJens Axboe int ret, do_wakeup, err; 6805274f052SJens Axboe 6815274f052SJens Axboe ret = 0; 6825274f052SJens Axboe do_wakeup = 0; 6835274f052SJens Axboe 6845274f052SJens Axboe for (;;) { 6856f767b04SJens Axboe if (pipe->nrbufs) { 6866f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 687d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6885274f052SJens Axboe 689c66ab6faSJens Axboe sd->len = buf->len; 690c66ab6faSJens Axboe if (sd->len > sd->total_len) 691c66ab6faSJens Axboe sd->len = sd->total_len; 6925274f052SJens Axboe 693c66ab6faSJens Axboe err = actor(pipe, buf, sd); 694016b661eSJens Axboe if (err <= 0) { 6955274f052SJens Axboe if (!ret && err != -ENODATA) 6965274f052SJens Axboe ret = err; 6975274f052SJens Axboe 6985274f052SJens Axboe break; 6995274f052SJens Axboe } 7005274f052SJens Axboe 701016b661eSJens Axboe ret += err; 702016b661eSJens Axboe buf->offset += err; 703016b661eSJens Axboe buf->len -= err; 704016b661eSJens Axboe 705c66ab6faSJens Axboe sd->len -= err; 706c66ab6faSJens Axboe sd->pos += err; 707c66ab6faSJens Axboe sd->total_len -= err; 708c66ab6faSJens Axboe if (sd->len) 709016b661eSJens Axboe continue; 71073d62d83SIngo Molnar 7115274f052SJens Axboe if (!buf->len) { 7125274f052SJens Axboe buf->ops = NULL; 7133a326a2cSIngo Molnar ops->release(pipe, buf); 7146f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7156f767b04SJens Axboe pipe->nrbufs--; 7166f767b04SJens Axboe if (pipe->inode) 7175274f052SJens Axboe do_wakeup = 1; 7185274f052SJens Axboe } 7195274f052SJens Axboe 720c66ab6faSJens Axboe if (!sd->total_len) 7215274f052SJens Axboe break; 7225274f052SJens Axboe } 7235274f052SJens Axboe 7246f767b04SJens Axboe if (pipe->nrbufs) 7255274f052SJens Axboe continue; 7263a326a2cSIngo Molnar if (!pipe->writers) 7275274f052SJens Axboe break; 7283a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7295274f052SJens Axboe if (ret) 7305274f052SJens Axboe break; 7315274f052SJens Axboe } 7325274f052SJens Axboe 733c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 73429e35094SLinus Torvalds if (!ret) 73529e35094SLinus Torvalds ret = -EAGAIN; 73629e35094SLinus Torvalds break; 73729e35094SLinus Torvalds } 73829e35094SLinus Torvalds 7395274f052SJens Axboe if (signal_pending(current)) { 7405274f052SJens Axboe if (!ret) 7415274f052SJens Axboe ret = -ERESTARTSYS; 7425274f052SJens Axboe break; 7435274f052SJens Axboe } 7445274f052SJens Axboe 7455274f052SJens Axboe if (do_wakeup) { 746c0bd1f65SJens Axboe smp_mb(); 7473a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7483a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7493a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7505274f052SJens Axboe do_wakeup = 0; 7515274f052SJens Axboe } 7525274f052SJens Axboe 7533a326a2cSIngo Molnar pipe_wait(pipe); 7545274f052SJens Axboe } 7555274f052SJens Axboe 7565274f052SJens Axboe if (do_wakeup) { 757c0bd1f65SJens Axboe smp_mb(); 7583a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7593a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7603a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7615274f052SJens Axboe } 7625274f052SJens Axboe 7635274f052SJens Axboe return ret; 7645274f052SJens Axboe } 76540bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7665274f052SJens Axboe 767932cc6d4SJens Axboe /** 768932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 769932cc6d4SJens Axboe * @pipe: pipe to splice from 770932cc6d4SJens Axboe * @out: file to splice to 771932cc6d4SJens Axboe * @ppos: position in @out 772932cc6d4SJens Axboe * @len: how many bytes to splice 773932cc6d4SJens Axboe * @flags: splice modifier flags 774932cc6d4SJens Axboe * @actor: handler that splices the data 775932cc6d4SJens Axboe * 776932cc6d4SJens Axboe * Description: 777932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 778932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 779932cc6d4SJens Axboe * 780932cc6d4SJens Axboe */ 7816da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7826da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7836da61809SMark Fasheh splice_actor *actor) 7846da61809SMark Fasheh { 7856da61809SMark Fasheh ssize_t ret; 7866da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 787c66ab6faSJens Axboe struct splice_desc sd = { 788c66ab6faSJens Axboe .total_len = len, 789c66ab6faSJens Axboe .flags = flags, 790c66ab6faSJens Axboe .pos = *ppos, 7916a14b90bSJens Axboe .u.file = out, 792c66ab6faSJens Axboe }; 7936da61809SMark Fasheh 7946da61809SMark Fasheh /* 7956da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7966da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7976da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7986da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7996da61809SMark Fasheh */ 8006da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 801c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 8026da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 8036da61809SMark Fasheh 8046da61809SMark Fasheh return ret; 8056da61809SMark Fasheh } 8066da61809SMark Fasheh 8076da61809SMark Fasheh /** 8086da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 8096da61809SMark Fasheh * @pipe: pipe info 8106da61809SMark Fasheh * @out: file to write to 811932cc6d4SJens Axboe * @ppos: position in @out 8126da61809SMark Fasheh * @len: number of bytes to splice 8136da61809SMark Fasheh * @flags: splice modifier flags 8146da61809SMark Fasheh * 815932cc6d4SJens Axboe * Description: 8166da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 8176da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 8186da61809SMark Fasheh * for acquiring i_mutex on both inodes. 8196da61809SMark Fasheh * 8206da61809SMark Fasheh */ 8216da61809SMark Fasheh ssize_t 8226da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 8236da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 8246da61809SMark Fasheh { 8256da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 8266da61809SMark Fasheh struct inode *inode = mapping->host; 827c66ab6faSJens Axboe struct splice_desc sd = { 828c66ab6faSJens Axboe .total_len = len, 829c66ab6faSJens Axboe .flags = flags, 830c66ab6faSJens Axboe .pos = *ppos, 8316a14b90bSJens Axboe .u.file = out, 832c66ab6faSJens Axboe }; 8336da61809SMark Fasheh ssize_t ret; 8346da61809SMark Fasheh int err; 8356da61809SMark Fasheh 8360f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 8378c34e2d6SJens Axboe if (unlikely(err)) 8388c34e2d6SJens Axboe return err; 8398c34e2d6SJens Axboe 840c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8416da61809SMark Fasheh if (ret > 0) { 84217ee4f49SJens Axboe unsigned long nr_pages; 84317ee4f49SJens Axboe 8446da61809SMark Fasheh *ppos += ret; 84517ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8466da61809SMark Fasheh 8476da61809SMark Fasheh /* 8486da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 8496da61809SMark Fasheh * sync it. 8506da61809SMark Fasheh */ 8516da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8526da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8536da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8546da61809SMark Fasheh 8556da61809SMark Fasheh if (err) 8566da61809SMark Fasheh ret = err; 8576da61809SMark Fasheh } 85817ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 8596da61809SMark Fasheh } 8606da61809SMark Fasheh 8616da61809SMark Fasheh return ret; 8626da61809SMark Fasheh } 8636da61809SMark Fasheh 8646da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8656da61809SMark Fasheh 86683f9135bSJens Axboe /** 86783f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8683a326a2cSIngo Molnar * @pipe: pipe info 86983f9135bSJens Axboe * @out: file to write to 870932cc6d4SJens Axboe * @ppos: position in @out 87183f9135bSJens Axboe * @len: number of bytes to splice 87283f9135bSJens Axboe * @flags: splice modifier flags 87383f9135bSJens Axboe * 874932cc6d4SJens Axboe * Description: 87583f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 87683f9135bSJens Axboe * the given pipe inode to the given file. 87783f9135bSJens Axboe * 87883f9135bSJens Axboe */ 8793a326a2cSIngo Molnar ssize_t 8803a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 881cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8825274f052SJens Axboe { 8834f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8848c34e2d6SJens Axboe struct inode *inode = mapping->host; 8853a326a2cSIngo Molnar ssize_t ret; 8868c34e2d6SJens Axboe int err; 8878c34e2d6SJens Axboe 8880f7fc9e4SJosef "Jeff" Sipek err = should_remove_suid(out->f_path.dentry); 8898c34e2d6SJens Axboe if (unlikely(err)) { 8908c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 8910f7fc9e4SJosef "Jeff" Sipek err = __remove_suid(out->f_path.dentry, err); 8928c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8938c34e2d6SJens Axboe if (err) 8948c34e2d6SJens Axboe return err; 8958c34e2d6SJens Axboe } 8963a326a2cSIngo Molnar 89700522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 898a4514ebdSJens Axboe if (ret > 0) { 89917ee4f49SJens Axboe unsigned long nr_pages; 90017ee4f49SJens Axboe 901a4514ebdSJens Axboe *ppos += ret; 90217ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 9034f6f0bd2SJens Axboe 9044f6f0bd2SJens Axboe /* 905a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 906a4514ebdSJens Axboe * sync it. 9074f6f0bd2SJens Axboe */ 908a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 9094f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 910a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 9114f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 9124f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 9134f6f0bd2SJens Axboe 9144f6f0bd2SJens Axboe if (err) 9154f6f0bd2SJens Axboe ret = err; 9164f6f0bd2SJens Axboe } 91717ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 918a4514ebdSJens Axboe } 9194f6f0bd2SJens Axboe 9204f6f0bd2SJens Axboe return ret; 9215274f052SJens Axboe } 9225274f052SJens Axboe 923059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 924059a8f37SJens Axboe 92583f9135bSJens Axboe /** 92683f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 927932cc6d4SJens Axboe * @pipe: pipe to splice from 92883f9135bSJens Axboe * @out: socket to write to 929932cc6d4SJens Axboe * @ppos: position in @out 93083f9135bSJens Axboe * @len: number of bytes to splice 93183f9135bSJens Axboe * @flags: splice modifier flags 93283f9135bSJens Axboe * 933932cc6d4SJens Axboe * Description: 93483f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 93583f9135bSJens Axboe * is involved. 93683f9135bSJens Axboe * 93783f9135bSJens Axboe */ 9383a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 939cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9405274f052SJens Axboe { 94100522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 9425274f052SJens Axboe } 9435274f052SJens Axboe 944059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 945a0f06780SJeff Garzik 94683f9135bSJens Axboe /* 94783f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 94883f9135bSJens Axboe */ 9493a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 950cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9515274f052SJens Axboe { 9525274f052SJens Axboe int ret; 9535274f052SJens Axboe 95449570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9555274f052SJens Axboe return -EINVAL; 9565274f052SJens Axboe 95749570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9585274f052SJens Axboe return -EBADF; 9595274f052SJens Axboe 960cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9615274f052SJens Axboe if (unlikely(ret < 0)) 9625274f052SJens Axboe return ret; 9635274f052SJens Axboe 964cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9655274f052SJens Axboe } 9665274f052SJens Axboe 96783f9135bSJens Axboe /* 96883f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 96983f9135bSJens Axboe */ 970cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 971cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 972cbb7e577SJens Axboe unsigned int flags) 9735274f052SJens Axboe { 9745274f052SJens Axboe int ret; 9755274f052SJens Axboe 97649570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9775274f052SJens Axboe return -EINVAL; 9785274f052SJens Axboe 97949570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9805274f052SJens Axboe return -EBADF; 9815274f052SJens Axboe 982cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9835274f052SJens Axboe if (unlikely(ret < 0)) 9845274f052SJens Axboe return ret; 9855274f052SJens Axboe 986cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9875274f052SJens Axboe } 9885274f052SJens Axboe 989932cc6d4SJens Axboe /** 990932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 991932cc6d4SJens Axboe * @in: file to splice from 992932cc6d4SJens Axboe * @sd: actor information on where to splice to 993932cc6d4SJens Axboe * @actor: handles the data splicing 994932cc6d4SJens Axboe * 995932cc6d4SJens Axboe * Description: 996932cc6d4SJens Axboe * This is a special case helper to splice directly between two 997932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 998932cc6d4SJens Axboe * pipe is cached in the process, and reused during the life time of 999932cc6d4SJens Axboe * that process. 1000932cc6d4SJens Axboe * 1001c66ab6faSJens Axboe */ 1002c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 1003c66ab6faSJens Axboe splice_direct_actor *actor) 1004b92ce558SJens Axboe { 1005b92ce558SJens Axboe struct pipe_inode_info *pipe; 1006b92ce558SJens Axboe long ret, bytes; 1007b92ce558SJens Axboe umode_t i_mode; 1008c66ab6faSJens Axboe size_t len; 1009c66ab6faSJens Axboe int i, flags; 1010b92ce558SJens Axboe 1011b92ce558SJens Axboe /* 1012b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 1013b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 1014b92ce558SJens Axboe * piped splicing for that! 1015b92ce558SJens Axboe */ 10160f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 1017b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 1018b92ce558SJens Axboe return -EINVAL; 1019b92ce558SJens Axboe 1020b92ce558SJens Axboe /* 1021b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 1022b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 1023b92ce558SJens Axboe */ 1024b92ce558SJens Axboe pipe = current->splice_pipe; 102549570e9bSJens Axboe if (unlikely(!pipe)) { 1026b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 1027b92ce558SJens Axboe if (!pipe) 1028b92ce558SJens Axboe return -ENOMEM; 1029b92ce558SJens Axboe 1030b92ce558SJens Axboe /* 1031b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 103200522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 1033b92ce558SJens Axboe * PIPE_READERS appropriately. 1034b92ce558SJens Axboe */ 1035b92ce558SJens Axboe pipe->readers = 1; 1036b92ce558SJens Axboe 1037b92ce558SJens Axboe current->splice_pipe = pipe; 1038b92ce558SJens Axboe } 1039b92ce558SJens Axboe 1040b92ce558SJens Axboe /* 104173d62d83SIngo Molnar * Do the splice. 1042b92ce558SJens Axboe */ 1043b92ce558SJens Axboe ret = 0; 1044b92ce558SJens Axboe bytes = 0; 1045c66ab6faSJens Axboe len = sd->total_len; 1046c66ab6faSJens Axboe flags = sd->flags; 1047c66ab6faSJens Axboe 1048c66ab6faSJens Axboe /* 1049c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1050c66ab6faSJens Axboe */ 1051c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1052b92ce558SJens Axboe 1053b92ce558SJens Axboe while (len) { 1054b92ce558SJens Axboe size_t read_len, max_read_len; 1055b92ce558SJens Axboe 1056b92ce558SJens Axboe /* 1057b92ce558SJens Axboe * Do at most PIPE_BUFFERS pages worth of transfer: 1058b92ce558SJens Axboe */ 1059b92ce558SJens Axboe max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); 1060b92ce558SJens Axboe 1061c66ab6faSJens Axboe ret = do_splice_to(in, &sd->pos, pipe, max_read_len, flags); 1062b92ce558SJens Axboe if (unlikely(ret < 0)) 1063b92ce558SJens Axboe goto out_release; 1064b92ce558SJens Axboe 1065b92ce558SJens Axboe read_len = ret; 1066c66ab6faSJens Axboe sd->total_len = read_len; 1067b92ce558SJens Axboe 1068b92ce558SJens Axboe /* 1069b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1070b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1071b92ce558SJens Axboe * could get stuck data in the internal pipe: 1072b92ce558SJens Axboe */ 1073c66ab6faSJens Axboe ret = actor(pipe, sd); 1074b92ce558SJens Axboe if (unlikely(ret < 0)) 1075b92ce558SJens Axboe goto out_release; 1076b92ce558SJens Axboe 1077b92ce558SJens Axboe bytes += ret; 1078b92ce558SJens Axboe len -= ret; 1079b92ce558SJens Axboe 1080b92ce558SJens Axboe /* 1081b92ce558SJens Axboe * In nonblocking mode, if we got back a short read then 1082b92ce558SJens Axboe * that was due to either an IO error or due to the 1083b92ce558SJens Axboe * pagecache entry not being there. In the IO error case 1084b92ce558SJens Axboe * the _next_ splice attempt will produce a clean IO error 1085b92ce558SJens Axboe * return value (not a short read), so in both cases it's 1086b92ce558SJens Axboe * correct to break out of the loop here: 1087b92ce558SJens Axboe */ 1088b92ce558SJens Axboe if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) 1089b92ce558SJens Axboe break; 1090b92ce558SJens Axboe } 1091b92ce558SJens Axboe 1092b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1093b92ce558SJens Axboe 1094b92ce558SJens Axboe return bytes; 1095b92ce558SJens Axboe 1096b92ce558SJens Axboe out_release: 1097b92ce558SJens Axboe /* 1098b92ce558SJens Axboe * If we did an incomplete transfer we must release 1099b92ce558SJens Axboe * the pipe buffers in question: 1100b92ce558SJens Axboe */ 1101b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1102b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1103b92ce558SJens Axboe 1104b92ce558SJens Axboe if (buf->ops) { 1105b92ce558SJens Axboe buf->ops->release(pipe, buf); 1106b92ce558SJens Axboe buf->ops = NULL; 1107b92ce558SJens Axboe } 1108b92ce558SJens Axboe } 1109b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1110b92ce558SJens Axboe 1111b92ce558SJens Axboe /* 1112b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1113b92ce558SJens Axboe */ 1114b92ce558SJens Axboe if (bytes > 0) 1115b92ce558SJens Axboe return bytes; 1116b92ce558SJens Axboe 1117b92ce558SJens Axboe return ret; 1118c66ab6faSJens Axboe 1119c66ab6faSJens Axboe } 1120c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1121c66ab6faSJens Axboe 1122c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1123c66ab6faSJens Axboe struct splice_desc *sd) 1124c66ab6faSJens Axboe { 11256a14b90bSJens Axboe struct file *file = sd->u.file; 1126c66ab6faSJens Axboe 1127c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1128c66ab6faSJens Axboe } 1129c66ab6faSJens Axboe 1130932cc6d4SJens Axboe /** 1131932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1132932cc6d4SJens Axboe * @in: file to splice from 1133932cc6d4SJens Axboe * @ppos: input file offset 1134932cc6d4SJens Axboe * @out: file to splice to 1135932cc6d4SJens Axboe * @len: number of bytes to splice 1136932cc6d4SJens Axboe * @flags: splice modifier flags 1137932cc6d4SJens Axboe * 1138932cc6d4SJens Axboe * Description: 1139932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1140932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1141932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1142932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1143932cc6d4SJens Axboe * 1144932cc6d4SJens Axboe */ 1145c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1146c66ab6faSJens Axboe size_t len, unsigned int flags) 1147c66ab6faSJens Axboe { 1148c66ab6faSJens Axboe struct splice_desc sd = { 1149c66ab6faSJens Axboe .len = len, 1150c66ab6faSJens Axboe .total_len = len, 1151c66ab6faSJens Axboe .flags = flags, 1152c66ab6faSJens Axboe .pos = *ppos, 11536a14b90bSJens Axboe .u.file = out, 1154c66ab6faSJens Axboe }; 1155c66ab6faSJens Axboe size_t ret; 1156c66ab6faSJens Axboe 1157c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 1158c66ab6faSJens Axboe *ppos = sd.pos; 1159c66ab6faSJens Axboe return ret; 1160b92ce558SJens Axboe } 1161b92ce558SJens Axboe 116283f9135bSJens Axboe /* 1163ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1164ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1165ddac0d39SJens Axboe * pipe. 1166ddac0d39SJens Axboe */ 1167ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1168ddac0d39SJens Axboe { 1169ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1170ddac0d39SJens Axboe return inode->i_pipe; 1171ddac0d39SJens Axboe 1172ddac0d39SJens Axboe return NULL; 1173ddac0d39SJens Axboe } 1174ddac0d39SJens Axboe 1175ddac0d39SJens Axboe /* 117683f9135bSJens Axboe * Determine where to splice to/from. 117783f9135bSJens Axboe */ 1178529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1179529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1180529565dcSIngo Molnar size_t len, unsigned int flags) 11815274f052SJens Axboe { 11823a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1183cbb7e577SJens Axboe loff_t offset, *off; 1184a4514ebdSJens Axboe long ret; 11855274f052SJens Axboe 11860f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1187529565dcSIngo Molnar if (pipe) { 1188529565dcSIngo Molnar if (off_in) 1189529565dcSIngo Molnar return -ESPIPE; 1190b92ce558SJens Axboe if (off_out) { 1191b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1192b92ce558SJens Axboe return -EINVAL; 1193cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1194b92ce558SJens Axboe return -EFAULT; 1195cbb7e577SJens Axboe off = &offset; 1196cbb7e577SJens Axboe } else 1197cbb7e577SJens Axboe off = &out->f_pos; 1198529565dcSIngo Molnar 1199a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1200a4514ebdSJens Axboe 1201a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1202a4514ebdSJens Axboe ret = -EFAULT; 1203a4514ebdSJens Axboe 1204a4514ebdSJens Axboe return ret; 1205529565dcSIngo Molnar } 12065274f052SJens Axboe 12070f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1208529565dcSIngo Molnar if (pipe) { 1209529565dcSIngo Molnar if (off_out) 1210529565dcSIngo Molnar return -ESPIPE; 1211b92ce558SJens Axboe if (off_in) { 1212b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1213b92ce558SJens Axboe return -EINVAL; 1214cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1215b92ce558SJens Axboe return -EFAULT; 1216cbb7e577SJens Axboe off = &offset; 1217cbb7e577SJens Axboe } else 1218cbb7e577SJens Axboe off = &in->f_pos; 1219529565dcSIngo Molnar 1220a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1221a4514ebdSJens Axboe 1222a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1223a4514ebdSJens Axboe ret = -EFAULT; 1224a4514ebdSJens Axboe 1225a4514ebdSJens Axboe return ret; 1226529565dcSIngo Molnar } 12275274f052SJens Axboe 12285274f052SJens Axboe return -EINVAL; 12295274f052SJens Axboe } 12305274f052SJens Axboe 1231912d35f8SJens Axboe /* 1232912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1233912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1234912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1235912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1236912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1237912d35f8SJens Axboe */ 1238912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1239912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 12407afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1241912d35f8SJens Axboe { 1242912d35f8SJens Axboe int buffers = 0, error = 0; 1243912d35f8SJens Axboe 1244912d35f8SJens Axboe /* 1245912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1246912d35f8SJens Axboe * across a "get_user()". 1247912d35f8SJens Axboe */ 1248912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1249912d35f8SJens Axboe 1250912d35f8SJens Axboe while (nr_vecs) { 1251912d35f8SJens Axboe unsigned long off, npages; 1252912d35f8SJens Axboe void __user *base; 1253912d35f8SJens Axboe size_t len; 1254912d35f8SJens Axboe int i; 1255912d35f8SJens Axboe 1256912d35f8SJens Axboe /* 1257912d35f8SJens Axboe * Get user address base and length for this iovec. 1258912d35f8SJens Axboe */ 1259912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1260912d35f8SJens Axboe if (unlikely(error)) 1261912d35f8SJens Axboe break; 1262912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1263912d35f8SJens Axboe if (unlikely(error)) 1264912d35f8SJens Axboe break; 1265912d35f8SJens Axboe 1266912d35f8SJens Axboe /* 1267912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1268912d35f8SJens Axboe */ 1269912d35f8SJens Axboe if (unlikely(!len)) 1270912d35f8SJens Axboe break; 1271912d35f8SJens Axboe error = -EFAULT; 1272912d35f8SJens Axboe if (unlikely(!base)) 1273912d35f8SJens Axboe break; 1274912d35f8SJens Axboe 1275912d35f8SJens Axboe /* 1276912d35f8SJens Axboe * Get this base offset and number of pages, then map 1277912d35f8SJens Axboe * in the user pages. 1278912d35f8SJens Axboe */ 1279912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12807afa6fd0SJens Axboe 12817afa6fd0SJens Axboe /* 12827afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12837afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12847afa6fd0SJens Axboe */ 12857afa6fd0SJens Axboe error = -EINVAL; 12867afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12877afa6fd0SJens Axboe break; 12887afa6fd0SJens Axboe 1289912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1290912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1291912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1292912d35f8SJens Axboe 1293912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1294912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1295912d35f8SJens Axboe &pages[buffers], NULL); 1296912d35f8SJens Axboe 1297912d35f8SJens Axboe if (unlikely(error <= 0)) 1298912d35f8SJens Axboe break; 1299912d35f8SJens Axboe 1300912d35f8SJens Axboe /* 1301912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1302912d35f8SJens Axboe */ 1303912d35f8SJens Axboe for (i = 0; i < error; i++) { 13047591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1305912d35f8SJens Axboe 1306912d35f8SJens Axboe partial[buffers].offset = off; 1307912d35f8SJens Axboe partial[buffers].len = plen; 1308912d35f8SJens Axboe 1309912d35f8SJens Axboe off = 0; 1310912d35f8SJens Axboe len -= plen; 1311912d35f8SJens Axboe buffers++; 1312912d35f8SJens Axboe } 1313912d35f8SJens Axboe 1314912d35f8SJens Axboe /* 1315912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1316912d35f8SJens Axboe * means we have to move some of this into a pipe to 1317912d35f8SJens Axboe * be able to continue. 1318912d35f8SJens Axboe */ 1319912d35f8SJens Axboe if (len) 1320912d35f8SJens Axboe break; 1321912d35f8SJens Axboe 1322912d35f8SJens Axboe /* 1323912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1324912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1325912d35f8SJens Axboe * room for. 1326912d35f8SJens Axboe */ 1327912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1328912d35f8SJens Axboe break; 1329912d35f8SJens Axboe 1330912d35f8SJens Axboe nr_vecs--; 1331912d35f8SJens Axboe iov++; 1332912d35f8SJens Axboe } 1333912d35f8SJens Axboe 1334912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1335912d35f8SJens Axboe 1336912d35f8SJens Axboe if (buffers) 1337912d35f8SJens Axboe return buffers; 1338912d35f8SJens Axboe 1339912d35f8SJens Axboe return error; 1340912d35f8SJens Axboe } 1341912d35f8SJens Axboe 13426a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13436a14b90bSJens Axboe struct splice_desc *sd) 13446a14b90bSJens Axboe { 13456a14b90bSJens Axboe char *src; 13466a14b90bSJens Axboe int ret; 13476a14b90bSJens Axboe 1348cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 13496a14b90bSJens Axboe if (unlikely(ret)) 13506a14b90bSJens Axboe return ret; 13516a14b90bSJens Axboe 13526a14b90bSJens Axboe /* 13536a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13546a14b90bSJens Axboe * pages and doing an atomic copy 13556a14b90bSJens Axboe */ 13566a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13576a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13586a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13596a14b90bSJens Axboe sd->len); 13606a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13616a14b90bSJens Axboe if (!ret) { 13626a14b90bSJens Axboe ret = sd->len; 13636a14b90bSJens Axboe goto out; 13646a14b90bSJens Axboe } 13656a14b90bSJens Axboe } 13666a14b90bSJens Axboe 13676a14b90bSJens Axboe /* 13686a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13696a14b90bSJens Axboe */ 13706a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13716a14b90bSJens Axboe 13726a14b90bSJens Axboe ret = sd->len; 13736a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13746a14b90bSJens Axboe ret = -EFAULT; 13756a14b90bSJens Axboe 13766a14b90bSJens Axboe out: 13776a14b90bSJens Axboe if (ret > 0) 13786a14b90bSJens Axboe sd->u.userptr += ret; 13796a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13806a14b90bSJens Axboe return ret; 13816a14b90bSJens Axboe } 13826a14b90bSJens Axboe 13836a14b90bSJens Axboe /* 13846a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13856a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13866a14b90bSJens Axboe */ 13876a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13886a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13896a14b90bSJens Axboe { 13906a14b90bSJens Axboe struct pipe_inode_info *pipe; 13916a14b90bSJens Axboe struct splice_desc sd; 13926a14b90bSJens Axboe ssize_t size; 13936a14b90bSJens Axboe int error; 13946a14b90bSJens Axboe long ret; 13956a14b90bSJens Axboe 13966a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13976a14b90bSJens Axboe if (!pipe) 13986a14b90bSJens Axboe return -EBADF; 13996a14b90bSJens Axboe 14006a14b90bSJens Axboe if (pipe->inode) 14016a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 14026a14b90bSJens Axboe 14036a14b90bSJens Axboe error = ret = 0; 14046a14b90bSJens Axboe while (nr_segs) { 14056a14b90bSJens Axboe void __user *base; 14066a14b90bSJens Axboe size_t len; 14076a14b90bSJens Axboe 14086a14b90bSJens Axboe /* 14096a14b90bSJens Axboe * Get user address base and length for this iovec. 14106a14b90bSJens Axboe */ 14116a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 14126a14b90bSJens Axboe if (unlikely(error)) 14136a14b90bSJens Axboe break; 14146a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 14156a14b90bSJens Axboe if (unlikely(error)) 14166a14b90bSJens Axboe break; 14176a14b90bSJens Axboe 14186a14b90bSJens Axboe /* 14196a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 14206a14b90bSJens Axboe */ 14216a14b90bSJens Axboe if (unlikely(!len)) 14226a14b90bSJens Axboe break; 14236a14b90bSJens Axboe if (unlikely(!base)) { 14246a14b90bSJens Axboe error = -EFAULT; 14256a14b90bSJens Axboe break; 14266a14b90bSJens Axboe } 14276a14b90bSJens Axboe 14286a14b90bSJens Axboe sd.len = 0; 14296a14b90bSJens Axboe sd.total_len = len; 14306a14b90bSJens Axboe sd.flags = flags; 14316a14b90bSJens Axboe sd.u.userptr = base; 14326a14b90bSJens Axboe sd.pos = 0; 14336a14b90bSJens Axboe 14346a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 14356a14b90bSJens Axboe if (size < 0) { 14366a14b90bSJens Axboe if (!ret) 14376a14b90bSJens Axboe ret = size; 14386a14b90bSJens Axboe 14396a14b90bSJens Axboe break; 14406a14b90bSJens Axboe } 14416a14b90bSJens Axboe 14426a14b90bSJens Axboe ret += size; 14436a14b90bSJens Axboe 14446a14b90bSJens Axboe if (size < len) 14456a14b90bSJens Axboe break; 14466a14b90bSJens Axboe 14476a14b90bSJens Axboe nr_segs--; 14486a14b90bSJens Axboe iov++; 14496a14b90bSJens Axboe } 14506a14b90bSJens Axboe 14516a14b90bSJens Axboe if (pipe->inode) 14526a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14536a14b90bSJens Axboe 14546a14b90bSJens Axboe if (!ret) 14556a14b90bSJens Axboe ret = error; 14566a14b90bSJens Axboe 14576a14b90bSJens Axboe return ret; 14586a14b90bSJens Axboe } 14596a14b90bSJens Axboe 1460912d35f8SJens Axboe /* 1461912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1462912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1463912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1464912d35f8SJens Axboe */ 14656a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1466912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1467912d35f8SJens Axboe { 1468ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1469912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1470912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1471912d35f8SJens Axboe struct splice_pipe_desc spd = { 1472912d35f8SJens Axboe .pages = pages, 1473912d35f8SJens Axboe .partial = partial, 1474912d35f8SJens Axboe .flags = flags, 1475912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1476912d35f8SJens Axboe }; 1477912d35f8SJens Axboe 14780f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1479ddac0d39SJens Axboe if (!pipe) 1480912d35f8SJens Axboe return -EBADF; 1481912d35f8SJens Axboe 14827afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14837afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1484912d35f8SJens Axboe if (spd.nr_pages <= 0) 1485912d35f8SJens Axboe return spd.nr_pages; 1486912d35f8SJens Axboe 148700522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1488912d35f8SJens Axboe } 1489912d35f8SJens Axboe 14906a14b90bSJens Axboe /* 14916a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14926a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14936a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14946a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14956a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14966a14b90bSJens Axboe * solutions for that: 14976a14b90bSJens Axboe * 14986a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14996a14b90bSJens Axboe * do a regular read() on the buffer anyway. 15006a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 15016a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 15026a14b90bSJens Axboe * 15036a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 15046a14b90bSJens Axboe * 15056a14b90bSJens Axboe */ 1506912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1507912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1508912d35f8SJens Axboe { 1509912d35f8SJens Axboe struct file *file; 1510912d35f8SJens Axboe long error; 1511912d35f8SJens Axboe int fput; 1512912d35f8SJens Axboe 15136a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 15146a14b90bSJens Axboe return -EINVAL; 15156a14b90bSJens Axboe else if (unlikely(!nr_segs)) 15166a14b90bSJens Axboe return 0; 15176a14b90bSJens Axboe 1518912d35f8SJens Axboe error = -EBADF; 1519912d35f8SJens Axboe file = fget_light(fd, &fput); 1520912d35f8SJens Axboe if (file) { 1521912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 15226a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 15236a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 15246a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1525912d35f8SJens Axboe 1526912d35f8SJens Axboe fput_light(file, fput); 1527912d35f8SJens Axboe } 1528912d35f8SJens Axboe 1529912d35f8SJens Axboe return error; 1530912d35f8SJens Axboe } 1531912d35f8SJens Axboe 1532529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1533529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1534529565dcSIngo Molnar size_t len, unsigned int flags) 15355274f052SJens Axboe { 15365274f052SJens Axboe long error; 15375274f052SJens Axboe struct file *in, *out; 15385274f052SJens Axboe int fput_in, fput_out; 15395274f052SJens Axboe 15405274f052SJens Axboe if (unlikely(!len)) 15415274f052SJens Axboe return 0; 15425274f052SJens Axboe 15435274f052SJens Axboe error = -EBADF; 1544529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 15455274f052SJens Axboe if (in) { 15465274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1547529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15485274f052SJens Axboe if (out) { 15495274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1550529565dcSIngo Molnar error = do_splice(in, off_in, 1551529565dcSIngo Molnar out, off_out, 1552529565dcSIngo Molnar len, flags); 15535274f052SJens Axboe fput_light(out, fput_out); 15545274f052SJens Axboe } 15555274f052SJens Axboe } 15565274f052SJens Axboe 15575274f052SJens Axboe fput_light(in, fput_in); 15585274f052SJens Axboe } 15595274f052SJens Axboe 15605274f052SJens Axboe return error; 15615274f052SJens Axboe } 156270524490SJens Axboe 156370524490SJens Axboe /* 1564aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1565aadd06e5SJens Axboe * return an appropriate error. 1566aadd06e5SJens Axboe */ 1567aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1568aadd06e5SJens Axboe { 1569aadd06e5SJens Axboe int ret; 1570aadd06e5SJens Axboe 1571aadd06e5SJens Axboe /* 1572aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1573aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1574aadd06e5SJens Axboe */ 1575aadd06e5SJens Axboe if (pipe->nrbufs) 1576aadd06e5SJens Axboe return 0; 1577aadd06e5SJens Axboe 1578aadd06e5SJens Axboe ret = 0; 1579aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1580aadd06e5SJens Axboe 1581aadd06e5SJens Axboe while (!pipe->nrbufs) { 1582aadd06e5SJens Axboe if (signal_pending(current)) { 1583aadd06e5SJens Axboe ret = -ERESTARTSYS; 1584aadd06e5SJens Axboe break; 1585aadd06e5SJens Axboe } 1586aadd06e5SJens Axboe if (!pipe->writers) 1587aadd06e5SJens Axboe break; 1588aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1589aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1590aadd06e5SJens Axboe ret = -EAGAIN; 1591aadd06e5SJens Axboe break; 1592aadd06e5SJens Axboe } 1593aadd06e5SJens Axboe } 1594aadd06e5SJens Axboe pipe_wait(pipe); 1595aadd06e5SJens Axboe } 1596aadd06e5SJens Axboe 1597aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1598aadd06e5SJens Axboe return ret; 1599aadd06e5SJens Axboe } 1600aadd06e5SJens Axboe 1601aadd06e5SJens Axboe /* 1602aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1603aadd06e5SJens Axboe * return an appropriate error. 1604aadd06e5SJens Axboe */ 1605aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1606aadd06e5SJens Axboe { 1607aadd06e5SJens Axboe int ret; 1608aadd06e5SJens Axboe 1609aadd06e5SJens Axboe /* 1610aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1611aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1612aadd06e5SJens Axboe */ 1613aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1614aadd06e5SJens Axboe return 0; 1615aadd06e5SJens Axboe 1616aadd06e5SJens Axboe ret = 0; 1617aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1618aadd06e5SJens Axboe 1619aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1620aadd06e5SJens Axboe if (!pipe->readers) { 1621aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1622aadd06e5SJens Axboe ret = -EPIPE; 1623aadd06e5SJens Axboe break; 1624aadd06e5SJens Axboe } 1625aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1626aadd06e5SJens Axboe ret = -EAGAIN; 1627aadd06e5SJens Axboe break; 1628aadd06e5SJens Axboe } 1629aadd06e5SJens Axboe if (signal_pending(current)) { 1630aadd06e5SJens Axboe ret = -ERESTARTSYS; 1631aadd06e5SJens Axboe break; 1632aadd06e5SJens Axboe } 1633aadd06e5SJens Axboe pipe->waiting_writers++; 1634aadd06e5SJens Axboe pipe_wait(pipe); 1635aadd06e5SJens Axboe pipe->waiting_writers--; 1636aadd06e5SJens Axboe } 1637aadd06e5SJens Axboe 1638aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1639aadd06e5SJens Axboe return ret; 1640aadd06e5SJens Axboe } 1641aadd06e5SJens Axboe 1642aadd06e5SJens Axboe /* 164370524490SJens Axboe * Link contents of ipipe to opipe. 164470524490SJens Axboe */ 164570524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 164670524490SJens Axboe struct pipe_inode_info *opipe, 164770524490SJens Axboe size_t len, unsigned int flags) 164870524490SJens Axboe { 164970524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1650aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 165170524490SJens Axboe 165270524490SJens Axboe /* 165370524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 165470524490SJens Axboe * grabbing by inode address. Otherwise two different processes 165570524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 165670524490SJens Axboe */ 165762752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 165870524490SJens Axboe 1659aadd06e5SJens Axboe do { 166070524490SJens Axboe if (!opipe->readers) { 166170524490SJens Axboe send_sig(SIGPIPE, current, 0); 166270524490SJens Axboe if (!ret) 166370524490SJens Axboe ret = -EPIPE; 166470524490SJens Axboe break; 166570524490SJens Axboe } 166670524490SJens Axboe 166770524490SJens Axboe /* 1668aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1669aadd06e5SJens Axboe * output room, break. 167070524490SJens Axboe */ 1671aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1672aadd06e5SJens Axboe break; 1673aadd06e5SJens Axboe 1674aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1675aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 167670524490SJens Axboe 167770524490SJens Axboe /* 167870524490SJens Axboe * Get a reference to this pipe buffer, 167970524490SJens Axboe * so we can copy the contents over. 168070524490SJens Axboe */ 168170524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 168270524490SJens Axboe 168370524490SJens Axboe obuf = opipe->bufs + nbuf; 168470524490SJens Axboe *obuf = *ibuf; 168570524490SJens Axboe 16867afa6fd0SJens Axboe /* 16877afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16887afa6fd0SJens Axboe * prevent multiple steals of this page. 16897afa6fd0SJens Axboe */ 16907afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16917afa6fd0SJens Axboe 169270524490SJens Axboe if (obuf->len > len) 169370524490SJens Axboe obuf->len = len; 169470524490SJens Axboe 169570524490SJens Axboe opipe->nrbufs++; 169670524490SJens Axboe ret += obuf->len; 169770524490SJens Axboe len -= obuf->len; 1698aadd06e5SJens Axboe i++; 1699aadd06e5SJens Axboe } while (len); 170070524490SJens Axboe 170162752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 170270524490SJens Axboe 1703aadd06e5SJens Axboe /* 1704aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1705aadd06e5SJens Axboe */ 1706aadd06e5SJens Axboe if (ret > 0) { 170770524490SJens Axboe smp_mb(); 170870524490SJens Axboe if (waitqueue_active(&opipe->wait)) 170970524490SJens Axboe wake_up_interruptible(&opipe->wait); 171070524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 171170524490SJens Axboe } 171270524490SJens Axboe 171370524490SJens Axboe return ret; 171470524490SJens Axboe } 171570524490SJens Axboe 171670524490SJens Axboe /* 171770524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 171870524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 171970524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 172070524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 172170524490SJens Axboe */ 172270524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 172370524490SJens Axboe unsigned int flags) 172470524490SJens Axboe { 17250f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 17260f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1727aadd06e5SJens Axboe int ret = -EINVAL; 172870524490SJens Axboe 172970524490SJens Axboe /* 1730aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1731aadd06e5SJens Axboe * copying the data. 173270524490SJens Axboe */ 1733aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1734aadd06e5SJens Axboe /* 1735aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1736aadd06e5SJens Axboe * ordering doesn't really matter. 1737aadd06e5SJens Axboe */ 1738aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1739aadd06e5SJens Axboe if (!ret) { 1740aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 1741aadd06e5SJens Axboe if (!ret) { 1742aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1743aadd06e5SJens Axboe if (!ret && (flags & SPLICE_F_NONBLOCK)) 1744aadd06e5SJens Axboe ret = -EAGAIN; 1745aadd06e5SJens Axboe } 1746aadd06e5SJens Axboe } 1747aadd06e5SJens Axboe } 174870524490SJens Axboe 1749aadd06e5SJens Axboe return ret; 175070524490SJens Axboe } 175170524490SJens Axboe 175270524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 175370524490SJens Axboe { 175470524490SJens Axboe struct file *in; 175570524490SJens Axboe int error, fput_in; 175670524490SJens Axboe 175770524490SJens Axboe if (unlikely(!len)) 175870524490SJens Axboe return 0; 175970524490SJens Axboe 176070524490SJens Axboe error = -EBADF; 176170524490SJens Axboe in = fget_light(fdin, &fput_in); 176270524490SJens Axboe if (in) { 176370524490SJens Axboe if (in->f_mode & FMODE_READ) { 176470524490SJens Axboe int fput_out; 176570524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 176670524490SJens Axboe 176770524490SJens Axboe if (out) { 176870524490SJens Axboe if (out->f_mode & FMODE_WRITE) 176970524490SJens Axboe error = do_tee(in, out, len, flags); 177070524490SJens Axboe fput_light(out, fput_out); 177170524490SJens Axboe } 177270524490SJens Axboe } 177370524490SJens Axboe fput_light(in, fput_in); 177470524490SJens Axboe } 177570524490SJens Axboe 177670524490SJens Axboe return error; 177770524490SJens Axboe } 1778