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> 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 */ 45d4c3cca9SEric Dumazet const 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 */ 5476ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 555abc97aaSJens Axboe struct pipe_buffer *buf) 565abc97aaSJens Axboe { 575abc97aaSJens Axboe struct page *page = buf->page; 589e94cd4fSJens Axboe struct address_space *mapping; 595abc97aaSJens Axboe 609e0267c2SJens Axboe lock_page(page); 619e0267c2SJens Axboe 629e94cd4fSJens Axboe mapping = page_mapping(page); 639e94cd4fSJens Axboe if (mapping) { 645abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 655abc97aaSJens Axboe 66ad8d6f0aSJens Axboe /* 679e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 689e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 699e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 709e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 719e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 729e94cd4fSJens Axboe * ensues. 73ad8d6f0aSJens Axboe */ 74ad8d6f0aSJens Axboe wait_on_page_writeback(page); 75ad8d6f0aSJens Axboe 764f6f0bd2SJens Axboe if (PagePrivate(page)) 772ae88149SNick Piggin try_to_release_page(page, GFP_KERNEL); 784f6f0bd2SJens Axboe 799e94cd4fSJens Axboe /* 809e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 819e94cd4fSJens Axboe * and return good. 829e94cd4fSJens Axboe */ 839e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 841432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 855abc97aaSJens Axboe return 0; 865abc97aaSJens Axboe } 879e94cd4fSJens Axboe } 889e94cd4fSJens Axboe 899e94cd4fSJens Axboe /* 909e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 919e94cd4fSJens Axboe * address space, unlock and return failure. 929e94cd4fSJens Axboe */ 939e94cd4fSJens Axboe unlock_page(page); 949e94cd4fSJens Axboe return 1; 959e94cd4fSJens Axboe } 965abc97aaSJens Axboe 9776ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 985274f052SJens Axboe struct pipe_buffer *buf) 995274f052SJens Axboe { 1005274f052SJens Axboe page_cache_release(buf->page); 1011432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 1025274f052SJens Axboe } 1035274f052SJens Axboe 10476ad4d11SJens Axboe static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe, 1055274f052SJens Axboe struct pipe_buffer *buf) 1065274f052SJens Axboe { 1075274f052SJens Axboe struct page *page = buf->page; 10849d0b21bSJens Axboe int err; 1095274f052SJens Axboe 1105274f052SJens Axboe if (!PageUptodate(page)) { 11149d0b21bSJens Axboe lock_page(page); 1125274f052SJens Axboe 11349d0b21bSJens Axboe /* 11449d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 11573d62d83SIngo Molnar * splice, if this is the first page. 11649d0b21bSJens Axboe */ 1175274f052SJens Axboe if (!page->mapping) { 11849d0b21bSJens Axboe err = -ENODATA; 11949d0b21bSJens Axboe goto error; 1205274f052SJens Axboe } 1215274f052SJens Axboe 12249d0b21bSJens Axboe /* 12373d62d83SIngo Molnar * Uh oh, read-error from disk. 12449d0b21bSJens Axboe */ 12549d0b21bSJens Axboe if (!PageUptodate(page)) { 12649d0b21bSJens Axboe err = -EIO; 12749d0b21bSJens Axboe goto error; 12849d0b21bSJens Axboe } 12949d0b21bSJens Axboe 13049d0b21bSJens Axboe /* 131f84d7519SJens Axboe * Page is ok afterall, we are done. 13249d0b21bSJens Axboe */ 13349d0b21bSJens Axboe unlock_page(page); 13449d0b21bSJens Axboe } 13549d0b21bSJens Axboe 136f84d7519SJens Axboe return 0; 13749d0b21bSJens Axboe error: 13849d0b21bSJens Axboe unlock_page(page); 139f84d7519SJens Axboe return err; 14070524490SJens Axboe } 14170524490SJens Axboe 142d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1435274f052SJens Axboe .can_merge = 0, 144f84d7519SJens Axboe .map = generic_pipe_buf_map, 145f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 146f84d7519SJens Axboe .pin = page_cache_pipe_buf_pin, 1475274f052SJens Axboe .release = page_cache_pipe_buf_release, 1485abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 149f84d7519SJens Axboe .get = generic_pipe_buf_get, 1505274f052SJens Axboe }; 1515274f052SJens Axboe 152912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 153912d35f8SJens Axboe struct pipe_buffer *buf) 154912d35f8SJens Axboe { 1557afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 156912d35f8SJens Axboe return 1; 1577afa6fd0SJens Axboe 1581432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 159330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 160912d35f8SJens Axboe } 161912d35f8SJens Axboe 162d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 163912d35f8SJens Axboe .can_merge = 0, 164f84d7519SJens Axboe .map = generic_pipe_buf_map, 165f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 166f84d7519SJens Axboe .pin = generic_pipe_buf_pin, 167912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 168912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 169f84d7519SJens Axboe .get = generic_pipe_buf_get, 170912d35f8SJens Axboe }; 171912d35f8SJens Axboe 17283f9135bSJens Axboe /* 17383f9135bSJens Axboe * Pipe output worker. This sets up our pipe format with the page cache 17483f9135bSJens Axboe * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). 17583f9135bSJens Axboe */ 17600522fb4SJens Axboe static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 177912d35f8SJens Axboe struct splice_pipe_desc *spd) 1785274f052SJens Axboe { 17900de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 180912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1815274f052SJens Axboe 1825274f052SJens Axboe ret = 0; 1835274f052SJens Axboe do_wakeup = 0; 184912d35f8SJens Axboe page_nr = 0; 1855274f052SJens Axboe 1863a326a2cSIngo Molnar if (pipe->inode) 1873a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1885274f052SJens Axboe 1895274f052SJens Axboe for (;;) { 1903a326a2cSIngo Molnar if (!pipe->readers) { 1915274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1925274f052SJens Axboe if (!ret) 1935274f052SJens Axboe ret = -EPIPE; 1945274f052SJens Axboe break; 1955274f052SJens Axboe } 1965274f052SJens Axboe 1976f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1986f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1993a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 2005274f052SJens Axboe 201912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 202912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 203912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 204912d35f8SJens Axboe buf->ops = spd->ops; 2057afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2067afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2077afa6fd0SJens Axboe 2086f767b04SJens Axboe pipe->nrbufs++; 209912d35f8SJens Axboe page_nr++; 210912d35f8SJens Axboe ret += buf->len; 211912d35f8SJens Axboe 2126f767b04SJens Axboe if (pipe->inode) 2135274f052SJens Axboe do_wakeup = 1; 2145274f052SJens Axboe 215912d35f8SJens Axboe if (!--spd->nr_pages) 2165274f052SJens Axboe break; 2176f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2185274f052SJens Axboe continue; 2195274f052SJens Axboe 2205274f052SJens Axboe break; 2215274f052SJens Axboe } 2225274f052SJens Axboe 223912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22429e35094SLinus Torvalds if (!ret) 22529e35094SLinus Torvalds ret = -EAGAIN; 22629e35094SLinus Torvalds break; 22729e35094SLinus Torvalds } 22829e35094SLinus Torvalds 2295274f052SJens Axboe if (signal_pending(current)) { 2305274f052SJens Axboe if (!ret) 2315274f052SJens Axboe ret = -ERESTARTSYS; 2325274f052SJens Axboe break; 2335274f052SJens Axboe } 2345274f052SJens Axboe 2355274f052SJens Axboe if (do_wakeup) { 236c0bd1f65SJens Axboe smp_mb(); 2373a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2383a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2393a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2405274f052SJens Axboe do_wakeup = 0; 2415274f052SJens Axboe } 2425274f052SJens Axboe 2433a326a2cSIngo Molnar pipe->waiting_writers++; 2443a326a2cSIngo Molnar pipe_wait(pipe); 2453a326a2cSIngo Molnar pipe->waiting_writers--; 2465274f052SJens Axboe } 2475274f052SJens Axboe 24802676e5aSJens Axboe if (pipe->inode) { 2493a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2505274f052SJens Axboe 2515274f052SJens Axboe if (do_wakeup) { 252c0bd1f65SJens Axboe smp_mb(); 2533a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2543a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2553a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2565274f052SJens Axboe } 25702676e5aSJens Axboe } 2585274f052SJens Axboe 25900de00bdSJens Axboe while (page_nr < spd_pages) 260912d35f8SJens Axboe page_cache_release(spd->pages[page_nr++]); 2615274f052SJens Axboe 2625274f052SJens Axboe return ret; 2635274f052SJens Axboe } 2645274f052SJens Axboe 2653a326a2cSIngo Molnar static int 266cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 267cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 268cbb7e577SJens Axboe unsigned int flags) 2695274f052SJens Axboe { 2705274f052SJens Axboe struct address_space *mapping = in->f_mapping; 271912d35f8SJens Axboe unsigned int loff, nr_pages; 27216c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 273912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2745274f052SJens Axboe struct page *page; 27591ad66efSJens Axboe pgoff_t index, end_index; 27691ad66efSJens Axboe loff_t isize; 277eb20796bSJens Axboe int error, page_nr; 278912d35f8SJens Axboe struct splice_pipe_desc spd = { 279912d35f8SJens Axboe .pages = pages, 280912d35f8SJens Axboe .partial = partial, 281912d35f8SJens Axboe .flags = flags, 282912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 283912d35f8SJens Axboe }; 2845274f052SJens Axboe 285cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 286912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 287912d35f8SJens Axboe nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2885274f052SJens Axboe 2895274f052SJens Axboe if (nr_pages > PIPE_BUFFERS) 2905274f052SJens Axboe nr_pages = PIPE_BUFFERS; 2915274f052SJens Axboe 2925274f052SJens Axboe /* 29386aa5ac5SJens Axboe * Don't try to 2nd guess the read-ahead logic, call into 29486aa5ac5SJens Axboe * page_cache_readahead() like the page cache reads would do. 2955274f052SJens Axboe */ 296eb645a24SJens Axboe page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); 2975274f052SJens Axboe 2985274f052SJens Axboe /* 29973d62d83SIngo Molnar * Now fill in the holes: 3005274f052SJens Axboe */ 3017480a904SJens Axboe error = 0; 30282aa5d61SJens Axboe 30382aa5d61SJens Axboe /* 304eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 30582aa5d61SJens Axboe */ 306eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 307eb20796bSJens Axboe 3085274f052SJens Axboe /* 309eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 310eb20796bSJens Axboe * allocate the rest. 311eb20796bSJens Axboe */ 312eb20796bSJens Axboe index += spd.nr_pages; 313eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 314eb20796bSJens Axboe /* 315eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 316eb20796bSJens Axboe * the first hole. 3175274f052SJens Axboe */ 3187480a904SJens Axboe page = find_get_page(mapping, index); 3197480a904SJens Axboe if (!page) { 3207480a904SJens Axboe /* 321e27dedd8SJens Axboe * Make sure the read-ahead engine is notified 322e27dedd8SJens Axboe * about this failure. 323e27dedd8SJens Axboe */ 324e27dedd8SJens Axboe handle_ra_miss(mapping, &in->f_ra, index); 325e27dedd8SJens Axboe 326e27dedd8SJens Axboe /* 327eb20796bSJens 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, 3342ae88149SNick Piggin GFP_KERNEL); 3355274f052SJens Axboe if (unlikely(error)) { 3365274f052SJens Axboe page_cache_release(page); 337a0548871SJens Axboe if (error == -EEXIST) 338a0548871SJens Axboe continue; 3395274f052SJens Axboe break; 3405274f052SJens Axboe } 341eb20796bSJens Axboe /* 342eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 343eb20796bSJens Axboe * to avoid convoluting the logic below even more. 344eb20796bSJens Axboe */ 345eb20796bSJens Axboe unlock_page(page); 3465274f052SJens Axboe } 3477480a904SJens Axboe 348eb20796bSJens Axboe pages[spd.nr_pages++] = page; 349eb20796bSJens Axboe index++; 350eb20796bSJens Axboe } 351eb20796bSJens Axboe 352eb20796bSJens Axboe /* 353eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 354eb20796bSJens Axboe * pages, fill in the partial map, etc. 355eb20796bSJens Axboe */ 356eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 357eb20796bSJens Axboe nr_pages = spd.nr_pages; 358eb20796bSJens Axboe spd.nr_pages = 0; 359eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 360eb20796bSJens Axboe unsigned int this_len; 361eb20796bSJens Axboe 362eb20796bSJens Axboe if (!len) 363eb20796bSJens Axboe break; 364eb20796bSJens Axboe 365eb20796bSJens Axboe /* 366eb20796bSJens Axboe * this_len is the max we'll use from this page 367eb20796bSJens Axboe */ 368eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 369eb20796bSJens Axboe page = pages[page_nr]; 370eb20796bSJens Axboe 3717480a904SJens Axboe /* 3727480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3737480a904SJens Axboe */ 3747480a904SJens Axboe if (!PageUptodate(page)) { 375c4f895cbSJens Axboe /* 376c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 377c4f895cbSJens Axboe * for an in-flight io page 378c4f895cbSJens Axboe */ 3799ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3809ae9d68cSFengguang Wu if (TestSetPageLocked(page)) 381c4f895cbSJens Axboe break; 3829ae9d68cSFengguang Wu } else 3837480a904SJens Axboe lock_page(page); 3847480a904SJens Axboe 3857480a904SJens Axboe /* 3867480a904SJens Axboe * page was truncated, stop here. if this isn't the 3877480a904SJens Axboe * first page, we'll just complete what we already 3887480a904SJens Axboe * added 3897480a904SJens Axboe */ 3907480a904SJens Axboe if (!page->mapping) { 3917480a904SJens Axboe unlock_page(page); 3927480a904SJens Axboe break; 3937480a904SJens Axboe } 3947480a904SJens Axboe /* 3957480a904SJens Axboe * page was already under io and is now done, great 3967480a904SJens Axboe */ 3977480a904SJens Axboe if (PageUptodate(page)) { 3987480a904SJens Axboe unlock_page(page); 3997480a904SJens Axboe goto fill_it; 4007480a904SJens Axboe } 4017480a904SJens Axboe 4027480a904SJens Axboe /* 4037480a904SJens Axboe * need to read in the page 4047480a904SJens Axboe */ 4057480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4067480a904SJens Axboe if (unlikely(error)) { 407eb20796bSJens Axboe /* 408eb20796bSJens Axboe * We really should re-lookup the page here, 409eb20796bSJens Axboe * but it complicates things a lot. Instead 410eb20796bSJens Axboe * lets just do what we already stored, and 411eb20796bSJens Axboe * we'll get it the next time we are called. 412eb20796bSJens Axboe */ 4137480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 414eb20796bSJens Axboe error = 0; 415eb20796bSJens Axboe 4167480a904SJens Axboe break; 4177480a904SJens Axboe } 418620a324bSJens Axboe } 419620a324bSJens Axboe fill_it: 42091ad66efSJens Axboe /* 421620a324bSJens Axboe * i_size must be checked after PageUptodate. 42291ad66efSJens Axboe */ 42391ad66efSJens Axboe isize = i_size_read(mapping->host); 42491ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 425eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 42691ad66efSJens Axboe break; 42791ad66efSJens Axboe 42891ad66efSJens Axboe /* 42991ad66efSJens Axboe * if this is the last page, see if we need to shrink 43091ad66efSJens Axboe * the length and stop 43191ad66efSJens Axboe */ 43291ad66efSJens Axboe if (end_index == index) { 433475ecadeSHugh Dickins unsigned int plen; 434475ecadeSHugh Dickins 435475ecadeSHugh Dickins /* 436475ecadeSHugh Dickins * max good bytes in this page 437475ecadeSHugh Dickins */ 438475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 439475ecadeSHugh Dickins if (plen <= loff) 44091ad66efSJens Axboe break; 441475ecadeSHugh Dickins 44291ad66efSJens Axboe /* 44391ad66efSJens Axboe * force quit after adding this page 44491ad66efSJens Axboe */ 445475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 446eb20796bSJens Axboe len = this_len; 44791ad66efSJens Axboe } 448620a324bSJens Axboe 449eb20796bSJens Axboe partial[page_nr].offset = loff; 450eb20796bSJens Axboe partial[page_nr].len = this_len; 45182aa5d61SJens Axboe len -= this_len; 45291ad66efSJens Axboe loff = 0; 453eb20796bSJens Axboe spd.nr_pages++; 454eb20796bSJens Axboe index++; 4555274f052SJens Axboe } 4565274f052SJens Axboe 457eb20796bSJens Axboe /* 458475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 459eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 460eb20796bSJens Axboe */ 461eb20796bSJens Axboe while (page_nr < nr_pages) 462eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 463eb20796bSJens Axboe 464912d35f8SJens Axboe if (spd.nr_pages) 46500522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 46616c523ddSJens Axboe 4677480a904SJens Axboe return error; 4685274f052SJens Axboe } 4695274f052SJens Axboe 47083f9135bSJens Axboe /** 47183f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 47283f9135bSJens Axboe * @in: file to splice from 47383f9135bSJens Axboe * @pipe: pipe to splice to 47483f9135bSJens Axboe * @len: number of bytes to splice 47583f9135bSJens Axboe * @flags: splice modifier flags 47683f9135bSJens Axboe * 47783f9135bSJens Axboe * Will read pages from given file and fill them into a pipe. 47883f9135bSJens Axboe */ 479cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 480cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 481cbb7e577SJens Axboe unsigned int flags) 4825274f052SJens Axboe { 4835274f052SJens Axboe ssize_t spliced; 4845274f052SJens Axboe int ret; 485d366d398SJens Axboe loff_t isize, left; 486d366d398SJens Axboe 487d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 488d366d398SJens Axboe if (unlikely(*ppos >= isize)) 489d366d398SJens Axboe return 0; 490d366d398SJens Axboe 491d366d398SJens Axboe left = isize - *ppos; 492d366d398SJens Axboe if (unlikely(left < len)) 493d366d398SJens Axboe len = left; 4945274f052SJens Axboe 4955274f052SJens Axboe ret = 0; 4965274f052SJens Axboe spliced = 0; 4975274f052SJens Axboe while (len) { 498cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4995274f052SJens Axboe 500c4f895cbSJens Axboe if (ret < 0) 5015274f052SJens Axboe break; 502c4f895cbSJens Axboe else if (!ret) { 503c4f895cbSJens Axboe if (spliced) 504c4f895cbSJens Axboe break; 505c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 506c4f895cbSJens Axboe ret = -EAGAIN; 507c4f895cbSJens Axboe break; 508c4f895cbSJens Axboe } 509c4f895cbSJens Axboe } 5105274f052SJens Axboe 511cbb7e577SJens Axboe *ppos += ret; 5125274f052SJens Axboe len -= ret; 5135274f052SJens Axboe spliced += ret; 5145274f052SJens Axboe } 5155274f052SJens Axboe 5165274f052SJens Axboe if (spliced) 5175274f052SJens Axboe return spliced; 5185274f052SJens Axboe 5195274f052SJens Axboe return ret; 5205274f052SJens Axboe } 5215274f052SJens Axboe 522059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 523059a8f37SJens Axboe 5245274f052SJens Axboe /* 5254f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 526016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5275274f052SJens Axboe */ 52876ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5295274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5305274f052SJens Axboe { 5316a14b90bSJens Axboe struct file *file = sd->u.file; 5325274f052SJens Axboe loff_t pos = sd->pos; 533f84d7519SJens Axboe int ret, more; 5345274f052SJens Axboe 53576ad4d11SJens Axboe ret = buf->ops->pin(pipe, buf); 536f84d7519SJens Axboe if (!ret) { 537b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5385274f052SJens Axboe 539f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 540f84d7519SJens Axboe sd->len, &pos, more); 541f84d7519SJens Axboe } 5425274f052SJens Axboe 543016b661eSJens Axboe return ret; 5445274f052SJens Axboe } 5455274f052SJens Axboe 5465274f052SJens Axboe /* 5475274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5485274f052SJens Axboe * basically three cases: 5495274f052SJens Axboe * 5505274f052SJens Axboe * - Destination page already exists in the address space and there 5515274f052SJens Axboe * are users of it. For that case we have no other option that 5525274f052SJens Axboe * copying the data. Tough luck. 5535274f052SJens Axboe * - Destination page already exists in the address space, but there 5545274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5555274f052SJens Axboe * through to last case. 5565274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5575274f052SJens Axboe * the page cache and avoid the copy. 5585274f052SJens Axboe * 55983f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 56083f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 56183f9135bSJens Axboe * file address space page cache. This is possible if no one else has 56283f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 56383f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 56483f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5655274f052SJens Axboe */ 56676ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5675274f052SJens Axboe struct splice_desc *sd) 5685274f052SJens Axboe { 5696a14b90bSJens Axboe struct file *file = sd->u.file; 5705274f052SJens Axboe struct address_space *mapping = file->f_mapping; 571016b661eSJens Axboe unsigned int offset, this_len; 5725274f052SJens Axboe struct page *page; 5735274f052SJens Axboe pgoff_t index; 5743e7ee3e7SJens Axboe int ret; 5755274f052SJens Axboe 5765274f052SJens Axboe /* 57749d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5785274f052SJens Axboe */ 57976ad4d11SJens Axboe ret = buf->ops->pin(pipe, buf); 580f84d7519SJens Axboe if (unlikely(ret)) 581f84d7519SJens Axboe return ret; 5825274f052SJens Axboe 5835274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5845274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5855274f052SJens Axboe 586016b661eSJens Axboe this_len = sd->len; 587016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 588016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 589016b661eSJens Axboe 5905274f052SJens Axboe find_page: 5919e0267c2SJens Axboe page = find_lock_page(mapping, index); 5929e0267c2SJens Axboe if (!page) { 5935274f052SJens Axboe ret = -ENOMEM; 5949e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5959e0267c2SJens Axboe if (unlikely(!page)) 596e6e80f29SJens Axboe goto out_ret; 5975274f052SJens Axboe 5985274f052SJens Axboe /* 5999e0267c2SJens Axboe * This will also lock the page 6009e0267c2SJens Axboe */ 6019e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 6022ae88149SNick Piggin GFP_KERNEL); 6039e0267c2SJens Axboe if (unlikely(ret)) 6049e0267c2SJens Axboe goto out; 6059e0267c2SJens Axboe } 6069e0267c2SJens Axboe 607016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 608bfc4ee39SJens Axboe if (unlikely(ret)) { 609bfc4ee39SJens Axboe loff_t isize = i_size_read(mapping->host); 610bfc4ee39SJens Axboe 611bfc4ee39SJens Axboe if (ret != AOP_TRUNCATED_PAGE) 612bfc4ee39SJens Axboe unlock_page(page); 6134f6f0bd2SJens Axboe page_cache_release(page); 614bfc4ee39SJens Axboe if (ret == AOP_TRUNCATED_PAGE) 6154f6f0bd2SJens Axboe goto find_page; 616bfc4ee39SJens Axboe 617bfc4ee39SJens Axboe /* 618bfc4ee39SJens Axboe * prepare_write() may have instantiated a few blocks 619bfc4ee39SJens Axboe * outside i_size. Trim these off again. 620bfc4ee39SJens Axboe */ 621bfc4ee39SJens Axboe if (sd->pos + this_len > isize) 622bfc4ee39SJens Axboe vmtruncate(mapping->host, isize); 623bfc4ee39SJens Axboe 624e6e80f29SJens Axboe goto out_ret; 625bfc4ee39SJens Axboe } 6265274f052SJens Axboe 6270568b409SJens Axboe if (buf->page != page) { 628f84d7519SJens Axboe /* 629f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 630f84d7519SJens Axboe */ 63176ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 632f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 6335abc97aaSJens Axboe 634016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6355274f052SJens Axboe flush_dcache_page(page); 636f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 63776ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6385abc97aaSJens Axboe } 6395274f052SJens Axboe 640016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 641d9993c37SDmitriy Monakhov if (ret) { 642d9993c37SDmitriy Monakhov if (ret == AOP_TRUNCATED_PAGE) { 643d9993c37SDmitriy Monakhov page_cache_release(page); 644d9993c37SDmitriy Monakhov goto find_page; 645d9993c37SDmitriy Monakhov } 646d9993c37SDmitriy Monakhov if (ret < 0) 647d9993c37SDmitriy Monakhov goto out; 648d9993c37SDmitriy Monakhov /* 649d9993c37SDmitriy Monakhov * Partial write has happened, so 'ret' already initialized by 650d9993c37SDmitriy Monakhov * number of bytes written, Where is nothing we have to do here. 651d9993c37SDmitriy Monakhov */ 652d9993c37SDmitriy Monakhov } else 653d9993c37SDmitriy Monakhov ret = this_len; 654016b661eSJens Axboe /* 6550568b409SJens Axboe * Return the number of bytes written and mark page as 6560568b409SJens Axboe * accessed, we are now done! 657016b661eSJens Axboe */ 658c7f21e4fSJens Axboe mark_page_accessed(page); 6590568b409SJens Axboe out: 6600568b409SJens Axboe page_cache_release(page); 6614f6f0bd2SJens Axboe unlock_page(page); 662e6e80f29SJens Axboe out_ret: 6635274f052SJens Axboe return ret; 6645274f052SJens Axboe } 6655274f052SJens Axboe 66683f9135bSJens Axboe /* 66783f9135bSJens Axboe * Pipe input worker. Most of this logic works like a regular pipe, the 66883f9135bSJens Axboe * key here is the 'actor' worker passed in that actually moves the data 66983f9135bSJens Axboe * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. 67083f9135bSJens Axboe */ 671c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 672c66ab6faSJens Axboe splice_actor *actor) 6735274f052SJens Axboe { 6745274f052SJens Axboe int ret, do_wakeup, err; 6755274f052SJens Axboe 6765274f052SJens Axboe ret = 0; 6775274f052SJens Axboe do_wakeup = 0; 6785274f052SJens Axboe 6795274f052SJens Axboe for (;;) { 6806f767b04SJens Axboe if (pipe->nrbufs) { 6816f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 682d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6835274f052SJens Axboe 684c66ab6faSJens Axboe sd->len = buf->len; 685c66ab6faSJens Axboe if (sd->len > sd->total_len) 686c66ab6faSJens Axboe sd->len = sd->total_len; 6875274f052SJens Axboe 688c66ab6faSJens Axboe err = actor(pipe, buf, sd); 689016b661eSJens Axboe if (err <= 0) { 6905274f052SJens Axboe if (!ret && err != -ENODATA) 6915274f052SJens Axboe ret = err; 6925274f052SJens Axboe 6935274f052SJens Axboe break; 6945274f052SJens Axboe } 6955274f052SJens Axboe 696016b661eSJens Axboe ret += err; 697016b661eSJens Axboe buf->offset += err; 698016b661eSJens Axboe buf->len -= err; 699016b661eSJens Axboe 700c66ab6faSJens Axboe sd->len -= err; 701c66ab6faSJens Axboe sd->pos += err; 702c66ab6faSJens Axboe sd->total_len -= err; 703c66ab6faSJens Axboe if (sd->len) 704016b661eSJens Axboe continue; 70573d62d83SIngo Molnar 7065274f052SJens Axboe if (!buf->len) { 7075274f052SJens Axboe buf->ops = NULL; 7083a326a2cSIngo Molnar ops->release(pipe, buf); 7096f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7106f767b04SJens Axboe pipe->nrbufs--; 7116f767b04SJens Axboe if (pipe->inode) 7125274f052SJens Axboe do_wakeup = 1; 7135274f052SJens Axboe } 7145274f052SJens Axboe 715c66ab6faSJens Axboe if (!sd->total_len) 7165274f052SJens Axboe break; 7175274f052SJens Axboe } 7185274f052SJens Axboe 7196f767b04SJens Axboe if (pipe->nrbufs) 7205274f052SJens Axboe continue; 7213a326a2cSIngo Molnar if (!pipe->writers) 7225274f052SJens Axboe break; 7233a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7245274f052SJens Axboe if (ret) 7255274f052SJens Axboe break; 7265274f052SJens Axboe } 7275274f052SJens Axboe 728c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 72929e35094SLinus Torvalds if (!ret) 73029e35094SLinus Torvalds ret = -EAGAIN; 73129e35094SLinus Torvalds break; 73229e35094SLinus Torvalds } 73329e35094SLinus Torvalds 7345274f052SJens Axboe if (signal_pending(current)) { 7355274f052SJens Axboe if (!ret) 7365274f052SJens Axboe ret = -ERESTARTSYS; 7375274f052SJens Axboe break; 7385274f052SJens Axboe } 7395274f052SJens Axboe 7405274f052SJens Axboe if (do_wakeup) { 741c0bd1f65SJens Axboe smp_mb(); 7423a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7433a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7443a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7455274f052SJens Axboe do_wakeup = 0; 7465274f052SJens Axboe } 7475274f052SJens Axboe 7483a326a2cSIngo Molnar pipe_wait(pipe); 7495274f052SJens Axboe } 7505274f052SJens Axboe 7515274f052SJens Axboe if (do_wakeup) { 752c0bd1f65SJens Axboe smp_mb(); 7533a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7543a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7553a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7565274f052SJens Axboe } 7575274f052SJens Axboe 7585274f052SJens Axboe return ret; 7595274f052SJens Axboe } 76040bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7615274f052SJens Axboe 7626da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7636da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7646da61809SMark Fasheh splice_actor *actor) 7656da61809SMark Fasheh { 7666da61809SMark Fasheh ssize_t ret; 7676da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 768c66ab6faSJens Axboe struct splice_desc sd = { 769c66ab6faSJens Axboe .total_len = len, 770c66ab6faSJens Axboe .flags = flags, 771c66ab6faSJens Axboe .pos = *ppos, 7726a14b90bSJens Axboe .u.file = out, 773c66ab6faSJens Axboe }; 7746da61809SMark Fasheh 7756da61809SMark Fasheh /* 7766da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7776da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7786da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7796da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7806da61809SMark Fasheh */ 7816da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 782c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7836da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7846da61809SMark Fasheh 7856da61809SMark Fasheh return ret; 7866da61809SMark Fasheh } 7876da61809SMark Fasheh 7886da61809SMark Fasheh /** 7896da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7906da61809SMark Fasheh * @pipe: pipe info 7916da61809SMark Fasheh * @out: file to write to 7926da61809SMark Fasheh * @len: number of bytes to splice 7936da61809SMark Fasheh * @flags: splice modifier flags 7946da61809SMark Fasheh * 7956da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7966da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7976da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7986da61809SMark Fasheh * 7996da61809SMark Fasheh */ 8006da61809SMark Fasheh ssize_t 8016da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 8026da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 8036da61809SMark Fasheh { 8046da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 8056da61809SMark Fasheh struct inode *inode = mapping->host; 806c66ab6faSJens Axboe struct splice_desc sd = { 807c66ab6faSJens Axboe .total_len = len, 808c66ab6faSJens Axboe .flags = flags, 809c66ab6faSJens Axboe .pos = *ppos, 8106a14b90bSJens Axboe .u.file = out, 811c66ab6faSJens Axboe }; 8126da61809SMark Fasheh ssize_t ret; 8136da61809SMark Fasheh int err; 8146da61809SMark Fasheh 8150f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 8168c34e2d6SJens Axboe if (unlikely(err)) 8178c34e2d6SJens Axboe return err; 8188c34e2d6SJens Axboe 819c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8206da61809SMark Fasheh if (ret > 0) { 82117ee4f49SJens Axboe unsigned long nr_pages; 82217ee4f49SJens Axboe 8236da61809SMark Fasheh *ppos += ret; 82417ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8256da61809SMark Fasheh 8266da61809SMark Fasheh /* 8276da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 8286da61809SMark Fasheh * sync it. 8296da61809SMark Fasheh */ 8306da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8316da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8326da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8336da61809SMark Fasheh 8346da61809SMark Fasheh if (err) 8356da61809SMark Fasheh ret = err; 8366da61809SMark Fasheh } 83717ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 8386da61809SMark Fasheh } 8396da61809SMark Fasheh 8406da61809SMark Fasheh return ret; 8416da61809SMark Fasheh } 8426da61809SMark Fasheh 8436da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8446da61809SMark Fasheh 84583f9135bSJens Axboe /** 84683f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8473a326a2cSIngo Molnar * @pipe: pipe info 84883f9135bSJens Axboe * @out: file to write to 84983f9135bSJens Axboe * @len: number of bytes to splice 85083f9135bSJens Axboe * @flags: splice modifier flags 85183f9135bSJens Axboe * 85283f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 85383f9135bSJens Axboe * the given pipe inode to the given file. 85483f9135bSJens Axboe * 85583f9135bSJens Axboe */ 8563a326a2cSIngo Molnar ssize_t 8573a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 858cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8595274f052SJens Axboe { 8604f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8618c34e2d6SJens Axboe struct inode *inode = mapping->host; 8623a326a2cSIngo Molnar ssize_t ret; 8638c34e2d6SJens Axboe int err; 8648c34e2d6SJens Axboe 8650f7fc9e4SJosef "Jeff" Sipek err = should_remove_suid(out->f_path.dentry); 8668c34e2d6SJens Axboe if (unlikely(err)) { 8678c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 8680f7fc9e4SJosef "Jeff" Sipek err = __remove_suid(out->f_path.dentry, err); 8698c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8708c34e2d6SJens Axboe if (err) 8718c34e2d6SJens Axboe return err; 8728c34e2d6SJens Axboe } 8733a326a2cSIngo Molnar 87400522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 875a4514ebdSJens Axboe if (ret > 0) { 87617ee4f49SJens Axboe unsigned long nr_pages; 87717ee4f49SJens Axboe 878a4514ebdSJens Axboe *ppos += ret; 87917ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8804f6f0bd2SJens Axboe 8814f6f0bd2SJens Axboe /* 882a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 883a4514ebdSJens Axboe * sync it. 8844f6f0bd2SJens Axboe */ 885a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8864f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 887a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8884f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8894f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8904f6f0bd2SJens Axboe 8914f6f0bd2SJens Axboe if (err) 8924f6f0bd2SJens Axboe ret = err; 8934f6f0bd2SJens Axboe } 89417ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 895a4514ebdSJens Axboe } 8964f6f0bd2SJens Axboe 8974f6f0bd2SJens Axboe return ret; 8985274f052SJens Axboe } 8995274f052SJens Axboe 900059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 901059a8f37SJens Axboe 90283f9135bSJens Axboe /** 90383f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 90483f9135bSJens Axboe * @inode: pipe inode 90583f9135bSJens Axboe * @out: socket to write to 90683f9135bSJens Axboe * @len: number of bytes to splice 90783f9135bSJens Axboe * @flags: splice modifier flags 90883f9135bSJens Axboe * 90983f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 91083f9135bSJens Axboe * is involved. 91183f9135bSJens Axboe * 91283f9135bSJens Axboe */ 9133a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 914cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9155274f052SJens Axboe { 91600522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 9175274f052SJens Axboe } 9185274f052SJens Axboe 919059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 920a0f06780SJeff Garzik 92183f9135bSJens Axboe /* 92283f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 92383f9135bSJens Axboe */ 9243a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 925cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9265274f052SJens Axboe { 9275274f052SJens Axboe int ret; 9285274f052SJens Axboe 92949570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9305274f052SJens Axboe return -EINVAL; 9315274f052SJens Axboe 93249570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9335274f052SJens Axboe return -EBADF; 9345274f052SJens Axboe 935cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9365274f052SJens Axboe if (unlikely(ret < 0)) 9375274f052SJens Axboe return ret; 9385274f052SJens Axboe 939cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9405274f052SJens Axboe } 9415274f052SJens Axboe 94283f9135bSJens Axboe /* 94383f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 94483f9135bSJens Axboe */ 945cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 946cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 947cbb7e577SJens Axboe unsigned int flags) 9485274f052SJens Axboe { 9495274f052SJens Axboe int ret; 9505274f052SJens Axboe 95149570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9525274f052SJens Axboe return -EINVAL; 9535274f052SJens Axboe 95449570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9555274f052SJens Axboe return -EBADF; 9565274f052SJens Axboe 957cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9585274f052SJens Axboe if (unlikely(ret < 0)) 9595274f052SJens Axboe return ret; 9605274f052SJens Axboe 961cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9625274f052SJens Axboe } 9635274f052SJens Axboe 964c66ab6faSJens Axboe /* 965c66ab6faSJens Axboe * Splices from an input file to an actor, using a 'direct' pipe. 966c66ab6faSJens Axboe */ 967c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 968c66ab6faSJens Axboe splice_direct_actor *actor) 969b92ce558SJens Axboe { 970b92ce558SJens Axboe struct pipe_inode_info *pipe; 971b92ce558SJens Axboe long ret, bytes; 972b92ce558SJens Axboe umode_t i_mode; 973c66ab6faSJens Axboe size_t len; 974c66ab6faSJens Axboe int i, flags; 975b92ce558SJens Axboe 976b92ce558SJens Axboe /* 977b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 978b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 979b92ce558SJens Axboe * piped splicing for that! 980b92ce558SJens Axboe */ 9810f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 982b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 983b92ce558SJens Axboe return -EINVAL; 984b92ce558SJens Axboe 985b92ce558SJens Axboe /* 986b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 987b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 988b92ce558SJens Axboe */ 989b92ce558SJens Axboe pipe = current->splice_pipe; 99049570e9bSJens Axboe if (unlikely(!pipe)) { 991b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 992b92ce558SJens Axboe if (!pipe) 993b92ce558SJens Axboe return -ENOMEM; 994b92ce558SJens Axboe 995b92ce558SJens Axboe /* 996b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 99700522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 998b92ce558SJens Axboe * PIPE_READERS appropriately. 999b92ce558SJens Axboe */ 1000b92ce558SJens Axboe pipe->readers = 1; 1001b92ce558SJens Axboe 1002b92ce558SJens Axboe current->splice_pipe = pipe; 1003b92ce558SJens Axboe } 1004b92ce558SJens Axboe 1005b92ce558SJens Axboe /* 100673d62d83SIngo Molnar * Do the splice. 1007b92ce558SJens Axboe */ 1008b92ce558SJens Axboe ret = 0; 1009b92ce558SJens Axboe bytes = 0; 1010c66ab6faSJens Axboe len = sd->total_len; 1011c66ab6faSJens Axboe flags = sd->flags; 1012c66ab6faSJens Axboe 1013c66ab6faSJens Axboe /* 1014c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1015c66ab6faSJens Axboe */ 1016c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1017b92ce558SJens Axboe 1018b92ce558SJens Axboe while (len) { 1019b92ce558SJens Axboe size_t read_len, max_read_len; 1020b92ce558SJens Axboe 1021b92ce558SJens Axboe /* 1022b92ce558SJens Axboe * Do at most PIPE_BUFFERS pages worth of transfer: 1023b92ce558SJens Axboe */ 1024b92ce558SJens Axboe max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); 1025b92ce558SJens Axboe 1026c66ab6faSJens Axboe ret = do_splice_to(in, &sd->pos, pipe, max_read_len, flags); 1027b92ce558SJens Axboe if (unlikely(ret < 0)) 1028b92ce558SJens Axboe goto out_release; 1029b92ce558SJens Axboe 1030b92ce558SJens Axboe read_len = ret; 1031c66ab6faSJens Axboe sd->total_len = read_len; 1032b92ce558SJens Axboe 1033b92ce558SJens Axboe /* 1034b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1035b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1036b92ce558SJens Axboe * could get stuck data in the internal pipe: 1037b92ce558SJens Axboe */ 1038c66ab6faSJens Axboe ret = actor(pipe, sd); 1039b92ce558SJens Axboe if (unlikely(ret < 0)) 1040b92ce558SJens Axboe goto out_release; 1041b92ce558SJens Axboe 1042b92ce558SJens Axboe bytes += ret; 1043b92ce558SJens Axboe len -= ret; 1044b92ce558SJens Axboe 1045b92ce558SJens Axboe /* 1046b92ce558SJens Axboe * In nonblocking mode, if we got back a short read then 1047b92ce558SJens Axboe * that was due to either an IO error or due to the 1048b92ce558SJens Axboe * pagecache entry not being there. In the IO error case 1049b92ce558SJens Axboe * the _next_ splice attempt will produce a clean IO error 1050b92ce558SJens Axboe * return value (not a short read), so in both cases it's 1051b92ce558SJens Axboe * correct to break out of the loop here: 1052b92ce558SJens Axboe */ 1053b92ce558SJens Axboe if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) 1054b92ce558SJens Axboe break; 1055b92ce558SJens Axboe } 1056b92ce558SJens Axboe 1057b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1058b92ce558SJens Axboe 1059b92ce558SJens Axboe return bytes; 1060b92ce558SJens Axboe 1061b92ce558SJens Axboe out_release: 1062b92ce558SJens Axboe /* 1063b92ce558SJens Axboe * If we did an incomplete transfer we must release 1064b92ce558SJens Axboe * the pipe buffers in question: 1065b92ce558SJens Axboe */ 1066b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1067b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1068b92ce558SJens Axboe 1069b92ce558SJens Axboe if (buf->ops) { 1070b92ce558SJens Axboe buf->ops->release(pipe, buf); 1071b92ce558SJens Axboe buf->ops = NULL; 1072b92ce558SJens Axboe } 1073b92ce558SJens Axboe } 1074b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1075b92ce558SJens Axboe 1076b92ce558SJens Axboe /* 1077b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1078b92ce558SJens Axboe */ 1079b92ce558SJens Axboe if (bytes > 0) 1080b92ce558SJens Axboe return bytes; 1081b92ce558SJens Axboe 1082b92ce558SJens Axboe return ret; 1083c66ab6faSJens Axboe 1084c66ab6faSJens Axboe } 1085c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1086c66ab6faSJens Axboe 1087c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1088c66ab6faSJens Axboe struct splice_desc *sd) 1089c66ab6faSJens Axboe { 10906a14b90bSJens Axboe struct file *file = sd->u.file; 1091c66ab6faSJens Axboe 1092c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1093c66ab6faSJens Axboe } 1094c66ab6faSJens Axboe 1095c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1096c66ab6faSJens Axboe size_t len, unsigned int flags) 1097c66ab6faSJens Axboe { 1098c66ab6faSJens Axboe struct splice_desc sd = { 1099c66ab6faSJens Axboe .len = len, 1100c66ab6faSJens Axboe .total_len = len, 1101c66ab6faSJens Axboe .flags = flags, 1102c66ab6faSJens Axboe .pos = *ppos, 11036a14b90bSJens Axboe .u.file = out, 1104c66ab6faSJens Axboe }; 1105c66ab6faSJens Axboe size_t ret; 1106c66ab6faSJens Axboe 1107c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 1108c66ab6faSJens Axboe *ppos = sd.pos; 1109c66ab6faSJens Axboe return ret; 1110b92ce558SJens Axboe } 1111b92ce558SJens Axboe 111283f9135bSJens Axboe /* 1113ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1114ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1115ddac0d39SJens Axboe * pipe. 1116ddac0d39SJens Axboe */ 1117ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1118ddac0d39SJens Axboe { 1119ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1120ddac0d39SJens Axboe return inode->i_pipe; 1121ddac0d39SJens Axboe 1122ddac0d39SJens Axboe return NULL; 1123ddac0d39SJens Axboe } 1124ddac0d39SJens Axboe 1125ddac0d39SJens Axboe /* 112683f9135bSJens Axboe * Determine where to splice to/from. 112783f9135bSJens Axboe */ 1128529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1129529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1130529565dcSIngo Molnar size_t len, unsigned int flags) 11315274f052SJens Axboe { 11323a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1133cbb7e577SJens Axboe loff_t offset, *off; 1134a4514ebdSJens Axboe long ret; 11355274f052SJens Axboe 11360f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1137529565dcSIngo Molnar if (pipe) { 1138529565dcSIngo Molnar if (off_in) 1139529565dcSIngo Molnar return -ESPIPE; 1140b92ce558SJens Axboe if (off_out) { 1141b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1142b92ce558SJens Axboe return -EINVAL; 1143cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1144b92ce558SJens Axboe return -EFAULT; 1145cbb7e577SJens Axboe off = &offset; 1146cbb7e577SJens Axboe } else 1147cbb7e577SJens Axboe off = &out->f_pos; 1148529565dcSIngo Molnar 1149a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1150a4514ebdSJens Axboe 1151a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1152a4514ebdSJens Axboe ret = -EFAULT; 1153a4514ebdSJens Axboe 1154a4514ebdSJens Axboe return ret; 1155529565dcSIngo Molnar } 11565274f052SJens Axboe 11570f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1158529565dcSIngo Molnar if (pipe) { 1159529565dcSIngo Molnar if (off_out) 1160529565dcSIngo Molnar return -ESPIPE; 1161b92ce558SJens Axboe if (off_in) { 1162b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1163b92ce558SJens Axboe return -EINVAL; 1164cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1165b92ce558SJens Axboe return -EFAULT; 1166cbb7e577SJens Axboe off = &offset; 1167cbb7e577SJens Axboe } else 1168cbb7e577SJens Axboe off = &in->f_pos; 1169529565dcSIngo Molnar 1170a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1171a4514ebdSJens Axboe 1172a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1173a4514ebdSJens Axboe ret = -EFAULT; 1174a4514ebdSJens Axboe 1175a4514ebdSJens Axboe return ret; 1176529565dcSIngo Molnar } 11775274f052SJens Axboe 11785274f052SJens Axboe return -EINVAL; 11795274f052SJens Axboe } 11805274f052SJens Axboe 1181912d35f8SJens Axboe /* 1182912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1183912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1184912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1185912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1186912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1187912d35f8SJens Axboe */ 1188912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1189912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 11907afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1191912d35f8SJens Axboe { 1192912d35f8SJens Axboe int buffers = 0, error = 0; 1193912d35f8SJens Axboe 1194912d35f8SJens Axboe /* 1195912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1196912d35f8SJens Axboe * across a "get_user()". 1197912d35f8SJens Axboe */ 1198912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1199912d35f8SJens Axboe 1200912d35f8SJens Axboe while (nr_vecs) { 1201912d35f8SJens Axboe unsigned long off, npages; 1202912d35f8SJens Axboe void __user *base; 1203912d35f8SJens Axboe size_t len; 1204912d35f8SJens Axboe int i; 1205912d35f8SJens Axboe 1206912d35f8SJens Axboe /* 1207912d35f8SJens Axboe * Get user address base and length for this iovec. 1208912d35f8SJens Axboe */ 1209912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1210912d35f8SJens Axboe if (unlikely(error)) 1211912d35f8SJens Axboe break; 1212912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1213912d35f8SJens Axboe if (unlikely(error)) 1214912d35f8SJens Axboe break; 1215912d35f8SJens Axboe 1216912d35f8SJens Axboe /* 1217912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1218912d35f8SJens Axboe */ 1219912d35f8SJens Axboe if (unlikely(!len)) 1220912d35f8SJens Axboe break; 1221912d35f8SJens Axboe error = -EFAULT; 1222912d35f8SJens Axboe if (unlikely(!base)) 1223912d35f8SJens Axboe break; 1224912d35f8SJens Axboe 1225912d35f8SJens Axboe /* 1226912d35f8SJens Axboe * Get this base offset and number of pages, then map 1227912d35f8SJens Axboe * in the user pages. 1228912d35f8SJens Axboe */ 1229912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12307afa6fd0SJens Axboe 12317afa6fd0SJens Axboe /* 12327afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12337afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12347afa6fd0SJens Axboe */ 12357afa6fd0SJens Axboe error = -EINVAL; 12367afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12377afa6fd0SJens Axboe break; 12387afa6fd0SJens Axboe 1239912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1240912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1241912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1242912d35f8SJens Axboe 1243912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1244912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1245912d35f8SJens Axboe &pages[buffers], NULL); 1246912d35f8SJens Axboe 1247912d35f8SJens Axboe if (unlikely(error <= 0)) 1248912d35f8SJens Axboe break; 1249912d35f8SJens Axboe 1250912d35f8SJens Axboe /* 1251912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1252912d35f8SJens Axboe */ 1253912d35f8SJens Axboe for (i = 0; i < error; i++) { 12547591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1255912d35f8SJens Axboe 1256912d35f8SJens Axboe partial[buffers].offset = off; 1257912d35f8SJens Axboe partial[buffers].len = plen; 1258912d35f8SJens Axboe 1259912d35f8SJens Axboe off = 0; 1260912d35f8SJens Axboe len -= plen; 1261912d35f8SJens Axboe buffers++; 1262912d35f8SJens Axboe } 1263912d35f8SJens Axboe 1264912d35f8SJens Axboe /* 1265912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1266912d35f8SJens Axboe * means we have to move some of this into a pipe to 1267912d35f8SJens Axboe * be able to continue. 1268912d35f8SJens Axboe */ 1269912d35f8SJens Axboe if (len) 1270912d35f8SJens Axboe break; 1271912d35f8SJens Axboe 1272912d35f8SJens Axboe /* 1273912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1274912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1275912d35f8SJens Axboe * room for. 1276912d35f8SJens Axboe */ 1277912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1278912d35f8SJens Axboe break; 1279912d35f8SJens Axboe 1280912d35f8SJens Axboe nr_vecs--; 1281912d35f8SJens Axboe iov++; 1282912d35f8SJens Axboe } 1283912d35f8SJens Axboe 1284912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1285912d35f8SJens Axboe 1286912d35f8SJens Axboe if (buffers) 1287912d35f8SJens Axboe return buffers; 1288912d35f8SJens Axboe 1289912d35f8SJens Axboe return error; 1290912d35f8SJens Axboe } 1291912d35f8SJens Axboe 12926a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12936a14b90bSJens Axboe struct splice_desc *sd) 12946a14b90bSJens Axboe { 12956a14b90bSJens Axboe char *src; 12966a14b90bSJens Axboe int ret; 12976a14b90bSJens Axboe 12986a14b90bSJens Axboe ret = buf->ops->pin(pipe, buf); 12996a14b90bSJens Axboe if (unlikely(ret)) 13006a14b90bSJens Axboe return ret; 13016a14b90bSJens Axboe 13026a14b90bSJens Axboe /* 13036a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13046a14b90bSJens Axboe * pages and doing an atomic copy 13056a14b90bSJens Axboe */ 13066a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13076a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13086a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13096a14b90bSJens Axboe sd->len); 13106a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13116a14b90bSJens Axboe if (!ret) { 13126a14b90bSJens Axboe ret = sd->len; 13136a14b90bSJens Axboe goto out; 13146a14b90bSJens Axboe } 13156a14b90bSJens Axboe } 13166a14b90bSJens Axboe 13176a14b90bSJens Axboe /* 13186a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13196a14b90bSJens Axboe */ 13206a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13216a14b90bSJens Axboe 13226a14b90bSJens Axboe ret = sd->len; 13236a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13246a14b90bSJens Axboe ret = -EFAULT; 13256a14b90bSJens Axboe 13266a14b90bSJens Axboe out: 13276a14b90bSJens Axboe if (ret > 0) 13286a14b90bSJens Axboe sd->u.userptr += ret; 13296a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13306a14b90bSJens Axboe return ret; 13316a14b90bSJens Axboe } 13326a14b90bSJens Axboe 13336a14b90bSJens Axboe /* 13346a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13356a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13366a14b90bSJens Axboe */ 13376a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13386a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13396a14b90bSJens Axboe { 13406a14b90bSJens Axboe struct pipe_inode_info *pipe; 13416a14b90bSJens Axboe struct splice_desc sd; 13426a14b90bSJens Axboe ssize_t size; 13436a14b90bSJens Axboe int error; 13446a14b90bSJens Axboe long ret; 13456a14b90bSJens Axboe 13466a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13476a14b90bSJens Axboe if (!pipe) 13486a14b90bSJens Axboe return -EBADF; 13496a14b90bSJens Axboe 13506a14b90bSJens Axboe if (pipe->inode) 13516a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13526a14b90bSJens Axboe 13536a14b90bSJens Axboe error = ret = 0; 13546a14b90bSJens Axboe while (nr_segs) { 13556a14b90bSJens Axboe void __user *base; 13566a14b90bSJens Axboe size_t len; 13576a14b90bSJens Axboe 13586a14b90bSJens Axboe /* 13596a14b90bSJens Axboe * Get user address base and length for this iovec. 13606a14b90bSJens Axboe */ 13616a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13626a14b90bSJens Axboe if (unlikely(error)) 13636a14b90bSJens Axboe break; 13646a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13656a14b90bSJens Axboe if (unlikely(error)) 13666a14b90bSJens Axboe break; 13676a14b90bSJens Axboe 13686a14b90bSJens Axboe /* 13696a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13706a14b90bSJens Axboe */ 13716a14b90bSJens Axboe if (unlikely(!len)) 13726a14b90bSJens Axboe break; 13736a14b90bSJens Axboe if (unlikely(!base)) { 13746a14b90bSJens Axboe error = -EFAULT; 13756a14b90bSJens Axboe break; 13766a14b90bSJens Axboe } 13776a14b90bSJens Axboe 13786a14b90bSJens Axboe sd.len = 0; 13796a14b90bSJens Axboe sd.total_len = len; 13806a14b90bSJens Axboe sd.flags = flags; 13816a14b90bSJens Axboe sd.u.userptr = base; 13826a14b90bSJens Axboe sd.pos = 0; 13836a14b90bSJens Axboe 13846a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 13856a14b90bSJens Axboe if (size < 0) { 13866a14b90bSJens Axboe if (!ret) 13876a14b90bSJens Axboe ret = size; 13886a14b90bSJens Axboe 13896a14b90bSJens Axboe break; 13906a14b90bSJens Axboe } 13916a14b90bSJens Axboe 13926a14b90bSJens Axboe ret += size; 13936a14b90bSJens Axboe 13946a14b90bSJens Axboe if (size < len) 13956a14b90bSJens Axboe break; 13966a14b90bSJens Axboe 13976a14b90bSJens Axboe nr_segs--; 13986a14b90bSJens Axboe iov++; 13996a14b90bSJens Axboe } 14006a14b90bSJens Axboe 14016a14b90bSJens Axboe if (pipe->inode) 14026a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14036a14b90bSJens Axboe 14046a14b90bSJens Axboe if (!ret) 14056a14b90bSJens Axboe ret = error; 14066a14b90bSJens Axboe 14076a14b90bSJens Axboe return ret; 14086a14b90bSJens Axboe } 14096a14b90bSJens Axboe 1410912d35f8SJens Axboe /* 1411912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1412912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1413912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1414912d35f8SJens Axboe */ 14156a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1416912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1417912d35f8SJens Axboe { 1418ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1419912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1420912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1421912d35f8SJens Axboe struct splice_pipe_desc spd = { 1422912d35f8SJens Axboe .pages = pages, 1423912d35f8SJens Axboe .partial = partial, 1424912d35f8SJens Axboe .flags = flags, 1425912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1426912d35f8SJens Axboe }; 1427912d35f8SJens Axboe 14280f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1429ddac0d39SJens Axboe if (!pipe) 1430912d35f8SJens Axboe return -EBADF; 1431912d35f8SJens Axboe 14327afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14337afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1434912d35f8SJens Axboe if (spd.nr_pages <= 0) 1435912d35f8SJens Axboe return spd.nr_pages; 1436912d35f8SJens Axboe 143700522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1438912d35f8SJens Axboe } 1439912d35f8SJens Axboe 14406a14b90bSJens Axboe /* 14416a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14426a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14436a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14446a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14456a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14466a14b90bSJens Axboe * solutions for that: 14476a14b90bSJens Axboe * 14486a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14496a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14506a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14516a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14526a14b90bSJens Axboe * 14536a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14546a14b90bSJens Axboe * 14556a14b90bSJens Axboe */ 1456912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1457912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1458912d35f8SJens Axboe { 1459912d35f8SJens Axboe struct file *file; 1460912d35f8SJens Axboe long error; 1461912d35f8SJens Axboe int fput; 1462912d35f8SJens Axboe 14636a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14646a14b90bSJens Axboe return -EINVAL; 14656a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14666a14b90bSJens Axboe return 0; 14676a14b90bSJens Axboe 1468912d35f8SJens Axboe error = -EBADF; 1469912d35f8SJens Axboe file = fget_light(fd, &fput); 1470912d35f8SJens Axboe if (file) { 1471912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14726a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14736a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14746a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1475912d35f8SJens Axboe 1476912d35f8SJens Axboe fput_light(file, fput); 1477912d35f8SJens Axboe } 1478912d35f8SJens Axboe 1479912d35f8SJens Axboe return error; 1480912d35f8SJens Axboe } 1481912d35f8SJens Axboe 1482529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1483529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1484529565dcSIngo Molnar size_t len, unsigned int flags) 14855274f052SJens Axboe { 14865274f052SJens Axboe long error; 14875274f052SJens Axboe struct file *in, *out; 14885274f052SJens Axboe int fput_in, fput_out; 14895274f052SJens Axboe 14905274f052SJens Axboe if (unlikely(!len)) 14915274f052SJens Axboe return 0; 14925274f052SJens Axboe 14935274f052SJens Axboe error = -EBADF; 1494529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 14955274f052SJens Axboe if (in) { 14965274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1497529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 14985274f052SJens Axboe if (out) { 14995274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1500529565dcSIngo Molnar error = do_splice(in, off_in, 1501529565dcSIngo Molnar out, off_out, 1502529565dcSIngo Molnar len, flags); 15035274f052SJens Axboe fput_light(out, fput_out); 15045274f052SJens Axboe } 15055274f052SJens Axboe } 15065274f052SJens Axboe 15075274f052SJens Axboe fput_light(in, fput_in); 15085274f052SJens Axboe } 15095274f052SJens Axboe 15105274f052SJens Axboe return error; 15115274f052SJens Axboe } 151270524490SJens Axboe 151370524490SJens Axboe /* 1514aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1515aadd06e5SJens Axboe * return an appropriate error. 1516aadd06e5SJens Axboe */ 1517aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1518aadd06e5SJens Axboe { 1519aadd06e5SJens Axboe int ret; 1520aadd06e5SJens Axboe 1521aadd06e5SJens Axboe /* 1522aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1523aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1524aadd06e5SJens Axboe */ 1525aadd06e5SJens Axboe if (pipe->nrbufs) 1526aadd06e5SJens Axboe return 0; 1527aadd06e5SJens Axboe 1528aadd06e5SJens Axboe ret = 0; 1529aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1530aadd06e5SJens Axboe 1531aadd06e5SJens Axboe while (!pipe->nrbufs) { 1532aadd06e5SJens Axboe if (signal_pending(current)) { 1533aadd06e5SJens Axboe ret = -ERESTARTSYS; 1534aadd06e5SJens Axboe break; 1535aadd06e5SJens Axboe } 1536aadd06e5SJens Axboe if (!pipe->writers) 1537aadd06e5SJens Axboe break; 1538aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1539aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1540aadd06e5SJens Axboe ret = -EAGAIN; 1541aadd06e5SJens Axboe break; 1542aadd06e5SJens Axboe } 1543aadd06e5SJens Axboe } 1544aadd06e5SJens Axboe pipe_wait(pipe); 1545aadd06e5SJens Axboe } 1546aadd06e5SJens Axboe 1547aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1548aadd06e5SJens Axboe return ret; 1549aadd06e5SJens Axboe } 1550aadd06e5SJens Axboe 1551aadd06e5SJens Axboe /* 1552aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1553aadd06e5SJens Axboe * return an appropriate error. 1554aadd06e5SJens Axboe */ 1555aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1556aadd06e5SJens Axboe { 1557aadd06e5SJens Axboe int ret; 1558aadd06e5SJens Axboe 1559aadd06e5SJens Axboe /* 1560aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1561aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1562aadd06e5SJens Axboe */ 1563aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1564aadd06e5SJens Axboe return 0; 1565aadd06e5SJens Axboe 1566aadd06e5SJens Axboe ret = 0; 1567aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1568aadd06e5SJens Axboe 1569aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1570aadd06e5SJens Axboe if (!pipe->readers) { 1571aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1572aadd06e5SJens Axboe ret = -EPIPE; 1573aadd06e5SJens Axboe break; 1574aadd06e5SJens Axboe } 1575aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1576aadd06e5SJens Axboe ret = -EAGAIN; 1577aadd06e5SJens Axboe break; 1578aadd06e5SJens Axboe } 1579aadd06e5SJens Axboe if (signal_pending(current)) { 1580aadd06e5SJens Axboe ret = -ERESTARTSYS; 1581aadd06e5SJens Axboe break; 1582aadd06e5SJens Axboe } 1583aadd06e5SJens Axboe pipe->waiting_writers++; 1584aadd06e5SJens Axboe pipe_wait(pipe); 1585aadd06e5SJens Axboe pipe->waiting_writers--; 1586aadd06e5SJens Axboe } 1587aadd06e5SJens Axboe 1588aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1589aadd06e5SJens Axboe return ret; 1590aadd06e5SJens Axboe } 1591aadd06e5SJens Axboe 1592aadd06e5SJens Axboe /* 159370524490SJens Axboe * Link contents of ipipe to opipe. 159470524490SJens Axboe */ 159570524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 159670524490SJens Axboe struct pipe_inode_info *opipe, 159770524490SJens Axboe size_t len, unsigned int flags) 159870524490SJens Axboe { 159970524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1600aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 160170524490SJens Axboe 160270524490SJens Axboe /* 160370524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 160470524490SJens Axboe * grabbing by inode address. Otherwise two different processes 160570524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 160670524490SJens Axboe */ 160762752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 160870524490SJens Axboe 1609aadd06e5SJens Axboe do { 161070524490SJens Axboe if (!opipe->readers) { 161170524490SJens Axboe send_sig(SIGPIPE, current, 0); 161270524490SJens Axboe if (!ret) 161370524490SJens Axboe ret = -EPIPE; 161470524490SJens Axboe break; 161570524490SJens Axboe } 161670524490SJens Axboe 161770524490SJens Axboe /* 1618aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1619aadd06e5SJens Axboe * output room, break. 162070524490SJens Axboe */ 1621aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1622aadd06e5SJens Axboe break; 1623aadd06e5SJens Axboe 1624aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1625aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 162670524490SJens Axboe 162770524490SJens Axboe /* 162870524490SJens Axboe * Get a reference to this pipe buffer, 162970524490SJens Axboe * so we can copy the contents over. 163070524490SJens Axboe */ 163170524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 163270524490SJens Axboe 163370524490SJens Axboe obuf = opipe->bufs + nbuf; 163470524490SJens Axboe *obuf = *ibuf; 163570524490SJens Axboe 16367afa6fd0SJens Axboe /* 16377afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16387afa6fd0SJens Axboe * prevent multiple steals of this page. 16397afa6fd0SJens Axboe */ 16407afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16417afa6fd0SJens Axboe 164270524490SJens Axboe if (obuf->len > len) 164370524490SJens Axboe obuf->len = len; 164470524490SJens Axboe 164570524490SJens Axboe opipe->nrbufs++; 164670524490SJens Axboe ret += obuf->len; 164770524490SJens Axboe len -= obuf->len; 1648aadd06e5SJens Axboe i++; 1649aadd06e5SJens Axboe } while (len); 165070524490SJens Axboe 165162752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 165270524490SJens Axboe 1653aadd06e5SJens Axboe /* 1654aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1655aadd06e5SJens Axboe */ 1656aadd06e5SJens Axboe if (ret > 0) { 165770524490SJens Axboe smp_mb(); 165870524490SJens Axboe if (waitqueue_active(&opipe->wait)) 165970524490SJens Axboe wake_up_interruptible(&opipe->wait); 166070524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 166170524490SJens Axboe } 166270524490SJens Axboe 166370524490SJens Axboe return ret; 166470524490SJens Axboe } 166570524490SJens Axboe 166670524490SJens Axboe /* 166770524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 166870524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 166970524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 167070524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 167170524490SJens Axboe */ 167270524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 167370524490SJens Axboe unsigned int flags) 167470524490SJens Axboe { 16750f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 16760f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1677aadd06e5SJens Axboe int ret = -EINVAL; 167870524490SJens Axboe 167970524490SJens Axboe /* 1680aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1681aadd06e5SJens Axboe * copying the data. 168270524490SJens Axboe */ 1683aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1684aadd06e5SJens Axboe /* 1685aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1686aadd06e5SJens Axboe * ordering doesn't really matter. 1687aadd06e5SJens Axboe */ 1688aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1689aadd06e5SJens Axboe if (!ret) { 1690aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 1691aadd06e5SJens Axboe if (!ret) { 1692aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1693aadd06e5SJens Axboe if (!ret && (flags & SPLICE_F_NONBLOCK)) 1694aadd06e5SJens Axboe ret = -EAGAIN; 1695aadd06e5SJens Axboe } 1696aadd06e5SJens Axboe } 1697aadd06e5SJens Axboe } 169870524490SJens Axboe 1699aadd06e5SJens Axboe return ret; 170070524490SJens Axboe } 170170524490SJens Axboe 170270524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 170370524490SJens Axboe { 170470524490SJens Axboe struct file *in; 170570524490SJens Axboe int error, fput_in; 170670524490SJens Axboe 170770524490SJens Axboe if (unlikely(!len)) 170870524490SJens Axboe return 0; 170970524490SJens Axboe 171070524490SJens Axboe error = -EBADF; 171170524490SJens Axboe in = fget_light(fdin, &fput_in); 171270524490SJens Axboe if (in) { 171370524490SJens Axboe if (in->f_mode & FMODE_READ) { 171470524490SJens Axboe int fput_out; 171570524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 171670524490SJens Axboe 171770524490SJens Axboe if (out) { 171870524490SJens Axboe if (out->f_mode & FMODE_WRITE) 171970524490SJens Axboe error = do_tee(in, out, len, flags); 172070524490SJens Axboe fput_light(out, fput_out); 172170524490SJens Axboe } 172270524490SJens Axboe } 172370524490SJens Axboe fput_light(in, fput_in); 172470524490SJens Axboe } 172570524490SJens Axboe 172670524490SJens Axboe return error; 172770524490SJens Axboe } 1728