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 { 179912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1805274f052SJens Axboe 1815274f052SJens Axboe ret = 0; 1825274f052SJens Axboe do_wakeup = 0; 183912d35f8SJens Axboe page_nr = 0; 1845274f052SJens Axboe 1853a326a2cSIngo Molnar if (pipe->inode) 1863a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1875274f052SJens Axboe 1885274f052SJens Axboe for (;;) { 1893a326a2cSIngo Molnar if (!pipe->readers) { 1905274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1915274f052SJens Axboe if (!ret) 1925274f052SJens Axboe ret = -EPIPE; 1935274f052SJens Axboe break; 1945274f052SJens Axboe } 1955274f052SJens Axboe 1966f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1976f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1983a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1995274f052SJens Axboe 200912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 201912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 202912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 203912d35f8SJens Axboe buf->ops = spd->ops; 2047afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2057afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2067afa6fd0SJens Axboe 2076f767b04SJens Axboe pipe->nrbufs++; 208912d35f8SJens Axboe page_nr++; 209912d35f8SJens Axboe ret += buf->len; 210912d35f8SJens Axboe 2116f767b04SJens Axboe if (pipe->inode) 2125274f052SJens Axboe do_wakeup = 1; 2135274f052SJens Axboe 214912d35f8SJens Axboe if (!--spd->nr_pages) 2155274f052SJens Axboe break; 2166f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2175274f052SJens Axboe continue; 2185274f052SJens Axboe 2195274f052SJens Axboe break; 2205274f052SJens Axboe } 2215274f052SJens Axboe 222912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22329e35094SLinus Torvalds if (!ret) 22429e35094SLinus Torvalds ret = -EAGAIN; 22529e35094SLinus Torvalds break; 22629e35094SLinus Torvalds } 22729e35094SLinus Torvalds 2285274f052SJens Axboe if (signal_pending(current)) { 2295274f052SJens Axboe if (!ret) 2305274f052SJens Axboe ret = -ERESTARTSYS; 2315274f052SJens Axboe break; 2325274f052SJens Axboe } 2335274f052SJens Axboe 2345274f052SJens Axboe if (do_wakeup) { 235c0bd1f65SJens Axboe smp_mb(); 2363a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2373a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2383a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2395274f052SJens Axboe do_wakeup = 0; 2405274f052SJens Axboe } 2415274f052SJens Axboe 2423a326a2cSIngo Molnar pipe->waiting_writers++; 2433a326a2cSIngo Molnar pipe_wait(pipe); 2443a326a2cSIngo Molnar pipe->waiting_writers--; 2455274f052SJens Axboe } 2465274f052SJens Axboe 2473a326a2cSIngo Molnar if (pipe->inode) 2483a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2495274f052SJens Axboe 2505274f052SJens Axboe if (do_wakeup) { 251c0bd1f65SJens Axboe smp_mb(); 2523a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2533a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2543a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2555274f052SJens Axboe } 2565274f052SJens Axboe 257912d35f8SJens Axboe while (page_nr < spd->nr_pages) 258912d35f8SJens Axboe page_cache_release(spd->pages[page_nr++]); 2595274f052SJens Axboe 2605274f052SJens Axboe return ret; 2615274f052SJens Axboe } 2625274f052SJens Axboe 2633a326a2cSIngo Molnar static int 264cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 265cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 266cbb7e577SJens Axboe unsigned int flags) 2675274f052SJens Axboe { 2685274f052SJens Axboe struct address_space *mapping = in->f_mapping; 269912d35f8SJens Axboe unsigned int loff, nr_pages; 27016c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 271912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2725274f052SJens Axboe struct page *page; 27391ad66efSJens Axboe pgoff_t index, end_index; 27491ad66efSJens Axboe loff_t isize; 275912d35f8SJens Axboe size_t total_len; 276eb20796bSJens Axboe int error, page_nr; 277912d35f8SJens Axboe struct splice_pipe_desc spd = { 278912d35f8SJens Axboe .pages = pages, 279912d35f8SJens Axboe .partial = partial, 280912d35f8SJens Axboe .flags = flags, 281912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 282912d35f8SJens Axboe }; 2835274f052SJens Axboe 284cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 285912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 286912d35f8SJens Axboe nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2875274f052SJens Axboe 2885274f052SJens Axboe if (nr_pages > PIPE_BUFFERS) 2895274f052SJens Axboe nr_pages = PIPE_BUFFERS; 2905274f052SJens Axboe 2915274f052SJens Axboe /* 29286aa5ac5SJens Axboe * Don't try to 2nd guess the read-ahead logic, call into 29386aa5ac5SJens Axboe * page_cache_readahead() like the page cache reads would do. 2945274f052SJens Axboe */ 295eb645a24SJens Axboe page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); 2965274f052SJens Axboe 2975274f052SJens Axboe /* 29873d62d83SIngo Molnar * Now fill in the holes: 2995274f052SJens Axboe */ 3007480a904SJens Axboe error = 0; 301912d35f8SJens Axboe total_len = 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 } 41891ad66efSJens Axboe 41991ad66efSJens Axboe /* 42091ad66efSJens Axboe * i_size must be checked after ->readpage(). 42191ad66efSJens Axboe */ 42291ad66efSJens Axboe isize = i_size_read(mapping->host); 42391ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 424eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 42591ad66efSJens Axboe break; 42691ad66efSJens Axboe 42791ad66efSJens Axboe /* 42891ad66efSJens Axboe * if this is the last page, see if we need to shrink 42991ad66efSJens Axboe * the length and stop 43091ad66efSJens Axboe */ 43191ad66efSJens Axboe if (end_index == index) { 43291ad66efSJens Axboe loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); 433eb20796bSJens Axboe if (total_len + loff > isize) 43491ad66efSJens Axboe break; 43591ad66efSJens Axboe /* 43691ad66efSJens Axboe * force quit after adding this page 43791ad66efSJens Axboe */ 438eb20796bSJens Axboe len = this_len; 43982aa5d61SJens Axboe this_len = min(this_len, loff); 440912d35f8SJens Axboe loff = 0; 44191ad66efSJens Axboe } 4427480a904SJens Axboe } 4437480a904SJens Axboe fill_it: 444eb20796bSJens Axboe partial[page_nr].offset = loff; 445eb20796bSJens Axboe partial[page_nr].len = this_len; 44682aa5d61SJens Axboe len -= this_len; 447912d35f8SJens Axboe total_len += this_len; 44891ad66efSJens Axboe loff = 0; 449eb20796bSJens Axboe spd.nr_pages++; 450eb20796bSJens Axboe index++; 4515274f052SJens Axboe } 4525274f052SJens Axboe 453eb20796bSJens Axboe /* 454eb20796bSJens Axboe * Release any pages at the end, if we quit early. 'i' is how far 455eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 456eb20796bSJens Axboe */ 457eb20796bSJens Axboe while (page_nr < nr_pages) 458eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 459eb20796bSJens Axboe 460912d35f8SJens Axboe if (spd.nr_pages) 46100522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 46216c523ddSJens Axboe 4637480a904SJens Axboe return error; 4645274f052SJens Axboe } 4655274f052SJens Axboe 46683f9135bSJens Axboe /** 46783f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46883f9135bSJens Axboe * @in: file to splice from 46983f9135bSJens Axboe * @pipe: pipe to splice to 47083f9135bSJens Axboe * @len: number of bytes to splice 47183f9135bSJens Axboe * @flags: splice modifier flags 47283f9135bSJens Axboe * 47383f9135bSJens Axboe * Will read pages from given file and fill them into a pipe. 47483f9135bSJens Axboe */ 475cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 476cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 477cbb7e577SJens Axboe unsigned int flags) 4785274f052SJens Axboe { 4795274f052SJens Axboe ssize_t spliced; 4805274f052SJens Axboe int ret; 4815274f052SJens Axboe 4825274f052SJens Axboe ret = 0; 4835274f052SJens Axboe spliced = 0; 4843a326a2cSIngo Molnar 4855274f052SJens Axboe while (len) { 486cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4875274f052SJens Axboe 488c4f895cbSJens Axboe if (ret < 0) 4895274f052SJens Axboe break; 490c4f895cbSJens Axboe else if (!ret) { 491c4f895cbSJens Axboe if (spliced) 492c4f895cbSJens Axboe break; 493c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 494c4f895cbSJens Axboe ret = -EAGAIN; 495c4f895cbSJens Axboe break; 496c4f895cbSJens Axboe } 497c4f895cbSJens Axboe } 4985274f052SJens Axboe 499cbb7e577SJens Axboe *ppos += ret; 5005274f052SJens Axboe len -= ret; 5015274f052SJens Axboe spliced += ret; 5025274f052SJens Axboe } 5035274f052SJens Axboe 5045274f052SJens Axboe if (spliced) 5055274f052SJens Axboe return spliced; 5065274f052SJens Axboe 5075274f052SJens Axboe return ret; 5085274f052SJens Axboe } 5095274f052SJens Axboe 510059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 511059a8f37SJens Axboe 5125274f052SJens Axboe /* 5134f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 514016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5155274f052SJens Axboe */ 51676ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5175274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5185274f052SJens Axboe { 5195274f052SJens Axboe struct file *file = sd->file; 5205274f052SJens Axboe loff_t pos = sd->pos; 521f84d7519SJens Axboe int ret, more; 5225274f052SJens Axboe 52376ad4d11SJens Axboe ret = buf->ops->pin(pipe, buf); 524f84d7519SJens Axboe if (!ret) { 525b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5265274f052SJens Axboe 527f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 528f84d7519SJens Axboe sd->len, &pos, more); 529f84d7519SJens Axboe } 5305274f052SJens Axboe 531016b661eSJens Axboe return ret; 5325274f052SJens Axboe } 5335274f052SJens Axboe 5345274f052SJens Axboe /* 5355274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5365274f052SJens Axboe * basically three cases: 5375274f052SJens Axboe * 5385274f052SJens Axboe * - Destination page already exists in the address space and there 5395274f052SJens Axboe * are users of it. For that case we have no other option that 5405274f052SJens Axboe * copying the data. Tough luck. 5415274f052SJens Axboe * - Destination page already exists in the address space, but there 5425274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5435274f052SJens Axboe * through to last case. 5445274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5455274f052SJens Axboe * the page cache and avoid the copy. 5465274f052SJens Axboe * 54783f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 54883f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 54983f9135bSJens Axboe * file address space page cache. This is possible if no one else has 55083f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 55183f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 55283f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5535274f052SJens Axboe */ 55476ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5555274f052SJens Axboe struct splice_desc *sd) 5565274f052SJens Axboe { 5575274f052SJens Axboe struct file *file = sd->file; 5585274f052SJens Axboe struct address_space *mapping = file->f_mapping; 559016b661eSJens Axboe unsigned int offset, this_len; 5605274f052SJens Axboe struct page *page; 5615274f052SJens Axboe pgoff_t index; 5623e7ee3e7SJens Axboe int ret; 5635274f052SJens Axboe 5645274f052SJens Axboe /* 56549d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5665274f052SJens Axboe */ 56776ad4d11SJens Axboe ret = buf->ops->pin(pipe, buf); 568f84d7519SJens Axboe if (unlikely(ret)) 569f84d7519SJens Axboe return ret; 5705274f052SJens Axboe 5715274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5725274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5735274f052SJens Axboe 574016b661eSJens Axboe this_len = sd->len; 575016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 576016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 577016b661eSJens Axboe 5785274f052SJens Axboe find_page: 5799e0267c2SJens Axboe page = find_lock_page(mapping, index); 5809e0267c2SJens Axboe if (!page) { 5815274f052SJens Axboe ret = -ENOMEM; 5829e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5839e0267c2SJens Axboe if (unlikely(!page)) 584e6e80f29SJens Axboe goto out_ret; 5855274f052SJens Axboe 5865274f052SJens Axboe /* 5879e0267c2SJens Axboe * This will also lock the page 5889e0267c2SJens Axboe */ 5899e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 5902ae88149SNick Piggin GFP_KERNEL); 5919e0267c2SJens Axboe if (unlikely(ret)) 5929e0267c2SJens Axboe goto out; 5939e0267c2SJens Axboe } 5949e0267c2SJens Axboe 595016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 596bfc4ee39SJens Axboe if (unlikely(ret)) { 597bfc4ee39SJens Axboe loff_t isize = i_size_read(mapping->host); 598bfc4ee39SJens Axboe 599bfc4ee39SJens Axboe if (ret != AOP_TRUNCATED_PAGE) 600bfc4ee39SJens Axboe unlock_page(page); 6014f6f0bd2SJens Axboe page_cache_release(page); 602bfc4ee39SJens Axboe if (ret == AOP_TRUNCATED_PAGE) 6034f6f0bd2SJens Axboe goto find_page; 604bfc4ee39SJens Axboe 605bfc4ee39SJens Axboe /* 606bfc4ee39SJens Axboe * prepare_write() may have instantiated a few blocks 607bfc4ee39SJens Axboe * outside i_size. Trim these off again. 608bfc4ee39SJens Axboe */ 609bfc4ee39SJens Axboe if (sd->pos + this_len > isize) 610bfc4ee39SJens Axboe vmtruncate(mapping->host, isize); 611bfc4ee39SJens Axboe 612e6e80f29SJens Axboe goto out_ret; 613bfc4ee39SJens Axboe } 6145274f052SJens Axboe 6150568b409SJens Axboe if (buf->page != page) { 616f84d7519SJens Axboe /* 617f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 618f84d7519SJens Axboe */ 61976ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 620f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 6215abc97aaSJens Axboe 622016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6235274f052SJens Axboe flush_dcache_page(page); 624f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 62576ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6265abc97aaSJens Axboe } 6275274f052SJens Axboe 628016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 629d9993c37SDmitriy Monakhov if (ret) { 630d9993c37SDmitriy Monakhov if (ret == AOP_TRUNCATED_PAGE) { 631d9993c37SDmitriy Monakhov page_cache_release(page); 632d9993c37SDmitriy Monakhov goto find_page; 633d9993c37SDmitriy Monakhov } 634d9993c37SDmitriy Monakhov if (ret < 0) 635d9993c37SDmitriy Monakhov goto out; 636d9993c37SDmitriy Monakhov /* 637d9993c37SDmitriy Monakhov * Partial write has happened, so 'ret' already initialized by 638d9993c37SDmitriy Monakhov * number of bytes written, Where is nothing we have to do here. 639d9993c37SDmitriy Monakhov */ 640d9993c37SDmitriy Monakhov } else 641d9993c37SDmitriy Monakhov ret = this_len; 642016b661eSJens Axboe /* 6430568b409SJens Axboe * Return the number of bytes written and mark page as 6440568b409SJens Axboe * accessed, we are now done! 645016b661eSJens Axboe */ 646c7f21e4fSJens Axboe mark_page_accessed(page); 6474f6f0bd2SJens Axboe balance_dirty_pages_ratelimited(mapping); 6480568b409SJens Axboe out: 6490568b409SJens Axboe page_cache_release(page); 6504f6f0bd2SJens Axboe unlock_page(page); 651e6e80f29SJens Axboe out_ret: 6525274f052SJens Axboe return ret; 6535274f052SJens Axboe } 6545274f052SJens Axboe 65583f9135bSJens Axboe /* 65683f9135bSJens Axboe * Pipe input worker. Most of this logic works like a regular pipe, the 65783f9135bSJens Axboe * key here is the 'actor' worker passed in that actually moves the data 65883f9135bSJens Axboe * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. 65983f9135bSJens Axboe */ 66040bee44eSMark Fasheh ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, 6616da61809SMark Fasheh struct file *out, loff_t *ppos, size_t len, 6626da61809SMark Fasheh unsigned int flags, splice_actor *actor) 6635274f052SJens Axboe { 6645274f052SJens Axboe int ret, do_wakeup, err; 6655274f052SJens Axboe struct splice_desc sd; 6665274f052SJens Axboe 6675274f052SJens Axboe ret = 0; 6685274f052SJens Axboe do_wakeup = 0; 6695274f052SJens Axboe 6705274f052SJens Axboe sd.total_len = len; 6715274f052SJens Axboe sd.flags = flags; 6725274f052SJens Axboe sd.file = out; 673cbb7e577SJens Axboe sd.pos = *ppos; 6745274f052SJens Axboe 6755274f052SJens Axboe for (;;) { 6766f767b04SJens Axboe if (pipe->nrbufs) { 6776f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 678d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6795274f052SJens Axboe 6805274f052SJens Axboe sd.len = buf->len; 6815274f052SJens Axboe if (sd.len > sd.total_len) 6825274f052SJens Axboe sd.len = sd.total_len; 6835274f052SJens Axboe 6843a326a2cSIngo Molnar err = actor(pipe, buf, &sd); 685016b661eSJens Axboe if (err <= 0) { 6865274f052SJens Axboe if (!ret && err != -ENODATA) 6875274f052SJens Axboe ret = err; 6885274f052SJens Axboe 6895274f052SJens Axboe break; 6905274f052SJens Axboe } 6915274f052SJens Axboe 692016b661eSJens Axboe ret += err; 693016b661eSJens Axboe buf->offset += err; 694016b661eSJens Axboe buf->len -= err; 695016b661eSJens Axboe 696016b661eSJens Axboe sd.len -= err; 697016b661eSJens Axboe sd.pos += err; 698016b661eSJens Axboe sd.total_len -= err; 699016b661eSJens Axboe if (sd.len) 700016b661eSJens Axboe continue; 70173d62d83SIngo Molnar 7025274f052SJens Axboe if (!buf->len) { 7035274f052SJens Axboe buf->ops = NULL; 7043a326a2cSIngo Molnar ops->release(pipe, buf); 7056f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7066f767b04SJens Axboe pipe->nrbufs--; 7076f767b04SJens Axboe if (pipe->inode) 7085274f052SJens Axboe do_wakeup = 1; 7095274f052SJens Axboe } 7105274f052SJens Axboe 7115274f052SJens Axboe if (!sd.total_len) 7125274f052SJens Axboe break; 7135274f052SJens Axboe } 7145274f052SJens Axboe 7156f767b04SJens Axboe if (pipe->nrbufs) 7165274f052SJens Axboe continue; 7173a326a2cSIngo Molnar if (!pipe->writers) 7185274f052SJens Axboe break; 7193a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7205274f052SJens Axboe if (ret) 7215274f052SJens Axboe break; 7225274f052SJens Axboe } 7235274f052SJens Axboe 72429e35094SLinus Torvalds if (flags & SPLICE_F_NONBLOCK) { 72529e35094SLinus Torvalds if (!ret) 72629e35094SLinus Torvalds ret = -EAGAIN; 72729e35094SLinus Torvalds break; 72829e35094SLinus Torvalds } 72929e35094SLinus Torvalds 7305274f052SJens Axboe if (signal_pending(current)) { 7315274f052SJens Axboe if (!ret) 7325274f052SJens Axboe ret = -ERESTARTSYS; 7335274f052SJens Axboe break; 7345274f052SJens Axboe } 7355274f052SJens Axboe 7365274f052SJens Axboe if (do_wakeup) { 737c0bd1f65SJens Axboe smp_mb(); 7383a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7393a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7403a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7415274f052SJens Axboe do_wakeup = 0; 7425274f052SJens Axboe } 7435274f052SJens Axboe 7443a326a2cSIngo Molnar pipe_wait(pipe); 7455274f052SJens Axboe } 7465274f052SJens Axboe 7475274f052SJens Axboe if (do_wakeup) { 748c0bd1f65SJens Axboe smp_mb(); 7493a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7503a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7513a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7525274f052SJens Axboe } 7535274f052SJens Axboe 7545274f052SJens Axboe return ret; 7555274f052SJens Axboe } 75640bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7575274f052SJens Axboe 7586da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7596da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7606da61809SMark Fasheh splice_actor *actor) 7616da61809SMark Fasheh { 7626da61809SMark Fasheh ssize_t ret; 7636da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 7646da61809SMark Fasheh 7656da61809SMark Fasheh /* 7666da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7676da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7686da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7696da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7706da61809SMark Fasheh */ 7716da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 7726da61809SMark Fasheh ret = __splice_from_pipe(pipe, out, ppos, len, flags, actor); 7736da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7746da61809SMark Fasheh 7756da61809SMark Fasheh return ret; 7766da61809SMark Fasheh } 7776da61809SMark Fasheh 7786da61809SMark Fasheh /** 7796da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7806da61809SMark Fasheh * @pipe: pipe info 7816da61809SMark Fasheh * @out: file to write to 7826da61809SMark Fasheh * @len: number of bytes to splice 7836da61809SMark Fasheh * @flags: splice modifier flags 7846da61809SMark Fasheh * 7856da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7866da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7876da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7886da61809SMark Fasheh * 7896da61809SMark Fasheh */ 7906da61809SMark Fasheh ssize_t 7916da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 7926da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 7936da61809SMark Fasheh { 7946da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 7956da61809SMark Fasheh struct inode *inode = mapping->host; 7966da61809SMark Fasheh ssize_t ret; 7976da61809SMark Fasheh int err; 7986da61809SMark Fasheh 7990f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 8008c34e2d6SJens Axboe if (unlikely(err)) 8018c34e2d6SJens Axboe return err; 8028c34e2d6SJens Axboe 8036da61809SMark Fasheh ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 8046da61809SMark Fasheh if (ret > 0) { 8056da61809SMark Fasheh *ppos += ret; 8066da61809SMark Fasheh 8076da61809SMark Fasheh /* 8086da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 8096da61809SMark Fasheh * sync it. 8106da61809SMark Fasheh */ 8116da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8126da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8136da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8146da61809SMark Fasheh 8156da61809SMark Fasheh if (err) 8166da61809SMark Fasheh ret = err; 8176da61809SMark Fasheh } 8186da61809SMark Fasheh } 8196da61809SMark Fasheh 8206da61809SMark Fasheh return ret; 8216da61809SMark Fasheh } 8226da61809SMark Fasheh 8236da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8246da61809SMark Fasheh 82583f9135bSJens Axboe /** 82683f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8273a326a2cSIngo Molnar * @pipe: pipe info 82883f9135bSJens Axboe * @out: file to write to 82983f9135bSJens Axboe * @len: number of bytes to splice 83083f9135bSJens Axboe * @flags: splice modifier flags 83183f9135bSJens Axboe * 83283f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 83383f9135bSJens Axboe * the given pipe inode to the given file. 83483f9135bSJens Axboe * 83583f9135bSJens Axboe */ 8363a326a2cSIngo Molnar ssize_t 8373a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 838cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8395274f052SJens Axboe { 8404f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8418c34e2d6SJens Axboe struct inode *inode = mapping->host; 8423a326a2cSIngo Molnar ssize_t ret; 8438c34e2d6SJens Axboe int err; 8448c34e2d6SJens Axboe 8450f7fc9e4SJosef "Jeff" Sipek err = should_remove_suid(out->f_path.dentry); 8468c34e2d6SJens Axboe if (unlikely(err)) { 8478c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 8480f7fc9e4SJosef "Jeff" Sipek err = __remove_suid(out->f_path.dentry, err); 8498c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8508c34e2d6SJens Axboe if (err) 8518c34e2d6SJens Axboe return err; 8528c34e2d6SJens Axboe } 8533a326a2cSIngo Molnar 85400522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 855a4514ebdSJens Axboe if (ret > 0) { 856a4514ebdSJens Axboe *ppos += ret; 8574f6f0bd2SJens Axboe 8584f6f0bd2SJens Axboe /* 859a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 860a4514ebdSJens Axboe * sync it. 8614f6f0bd2SJens Axboe */ 862a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8634f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 864a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8654f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8664f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8674f6f0bd2SJens Axboe 8684f6f0bd2SJens Axboe if (err) 8694f6f0bd2SJens Axboe ret = err; 8704f6f0bd2SJens Axboe } 871a4514ebdSJens Axboe } 8724f6f0bd2SJens Axboe 8734f6f0bd2SJens Axboe return ret; 8745274f052SJens Axboe } 8755274f052SJens Axboe 876059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 877059a8f37SJens Axboe 87883f9135bSJens Axboe /** 87983f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 88083f9135bSJens Axboe * @inode: pipe inode 88183f9135bSJens Axboe * @out: socket to write to 88283f9135bSJens Axboe * @len: number of bytes to splice 88383f9135bSJens Axboe * @flags: splice modifier flags 88483f9135bSJens Axboe * 88583f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 88683f9135bSJens Axboe * is involved. 88783f9135bSJens Axboe * 88883f9135bSJens Axboe */ 8893a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 890cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8915274f052SJens Axboe { 89200522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8935274f052SJens Axboe } 8945274f052SJens Axboe 895059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 896a0f06780SJeff Garzik 89783f9135bSJens Axboe /* 89883f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 89983f9135bSJens Axboe */ 9003a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 901cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9025274f052SJens Axboe { 9035274f052SJens Axboe int ret; 9045274f052SJens Axboe 90549570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9065274f052SJens Axboe return -EINVAL; 9075274f052SJens Axboe 90849570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9095274f052SJens Axboe return -EBADF; 9105274f052SJens Axboe 911cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9125274f052SJens Axboe if (unlikely(ret < 0)) 9135274f052SJens Axboe return ret; 9145274f052SJens Axboe 915cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9165274f052SJens Axboe } 9175274f052SJens Axboe 91883f9135bSJens Axboe /* 91983f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 92083f9135bSJens Axboe */ 921cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 922cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 923cbb7e577SJens Axboe unsigned int flags) 9245274f052SJens Axboe { 925cbb7e577SJens Axboe loff_t isize, left; 9265274f052SJens Axboe int ret; 9275274f052SJens Axboe 92849570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9295274f052SJens Axboe return -EINVAL; 9305274f052SJens Axboe 93149570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9325274f052SJens Axboe return -EBADF; 9335274f052SJens Axboe 934cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9355274f052SJens Axboe if (unlikely(ret < 0)) 9365274f052SJens Axboe return ret; 9375274f052SJens Axboe 9385274f052SJens Axboe isize = i_size_read(in->f_mapping->host); 939cbb7e577SJens Axboe if (unlikely(*ppos >= isize)) 9405274f052SJens Axboe return 0; 9415274f052SJens Axboe 942cbb7e577SJens Axboe left = isize - *ppos; 94349570e9bSJens Axboe if (unlikely(left < len)) 9445274f052SJens Axboe len = left; 9455274f052SJens Axboe 946cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9475274f052SJens Axboe } 9485274f052SJens Axboe 949cbb7e577SJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 950cbb7e577SJens Axboe size_t len, unsigned int flags) 951b92ce558SJens Axboe { 952b92ce558SJens Axboe struct pipe_inode_info *pipe; 953b92ce558SJens Axboe long ret, bytes; 954cbb7e577SJens Axboe loff_t out_off; 955b92ce558SJens Axboe umode_t i_mode; 956b92ce558SJens Axboe int i; 957b92ce558SJens Axboe 958b92ce558SJens Axboe /* 959b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 960b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 961b92ce558SJens Axboe * piped splicing for that! 962b92ce558SJens Axboe */ 9630f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 964b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 965b92ce558SJens Axboe return -EINVAL; 966b92ce558SJens Axboe 967b92ce558SJens Axboe /* 968b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 969b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 970b92ce558SJens Axboe */ 971b92ce558SJens Axboe pipe = current->splice_pipe; 97249570e9bSJens Axboe if (unlikely(!pipe)) { 973b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 974b92ce558SJens Axboe if (!pipe) 975b92ce558SJens Axboe return -ENOMEM; 976b92ce558SJens Axboe 977b92ce558SJens Axboe /* 978b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 97900522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 980b92ce558SJens Axboe * PIPE_READERS appropriately. 981b92ce558SJens Axboe */ 982b92ce558SJens Axboe pipe->readers = 1; 983b92ce558SJens Axboe 984b92ce558SJens Axboe current->splice_pipe = pipe; 985b92ce558SJens Axboe } 986b92ce558SJens Axboe 987b92ce558SJens Axboe /* 98873d62d83SIngo Molnar * Do the splice. 989b92ce558SJens Axboe */ 990b92ce558SJens Axboe ret = 0; 991b92ce558SJens Axboe bytes = 0; 992cbb7e577SJens Axboe out_off = 0; 993b92ce558SJens Axboe 994b92ce558SJens Axboe while (len) { 995b92ce558SJens Axboe size_t read_len, max_read_len; 996b92ce558SJens Axboe 997b92ce558SJens Axboe /* 998b92ce558SJens Axboe * Do at most PIPE_BUFFERS pages worth of transfer: 999b92ce558SJens Axboe */ 1000b92ce558SJens Axboe max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); 1001b92ce558SJens Axboe 1002cbb7e577SJens Axboe ret = do_splice_to(in, ppos, pipe, max_read_len, flags); 1003b92ce558SJens Axboe if (unlikely(ret < 0)) 1004b92ce558SJens Axboe goto out_release; 1005b92ce558SJens Axboe 1006b92ce558SJens Axboe read_len = ret; 1007b92ce558SJens Axboe 1008b92ce558SJens Axboe /* 1009b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1010b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1011b92ce558SJens Axboe * could get stuck data in the internal pipe: 1012b92ce558SJens Axboe */ 1013cbb7e577SJens Axboe ret = do_splice_from(pipe, out, &out_off, read_len, 1014b92ce558SJens Axboe flags & ~SPLICE_F_NONBLOCK); 1015b92ce558SJens Axboe if (unlikely(ret < 0)) 1016b92ce558SJens Axboe goto out_release; 1017b92ce558SJens Axboe 1018b92ce558SJens Axboe bytes += ret; 1019b92ce558SJens Axboe len -= ret; 1020b92ce558SJens Axboe 1021b92ce558SJens Axboe /* 1022b92ce558SJens Axboe * In nonblocking mode, if we got back a short read then 1023b92ce558SJens Axboe * that was due to either an IO error or due to the 1024b92ce558SJens Axboe * pagecache entry not being there. In the IO error case 1025b92ce558SJens Axboe * the _next_ splice attempt will produce a clean IO error 1026b92ce558SJens Axboe * return value (not a short read), so in both cases it's 1027b92ce558SJens Axboe * correct to break out of the loop here: 1028b92ce558SJens Axboe */ 1029b92ce558SJens Axboe if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) 1030b92ce558SJens Axboe break; 1031b92ce558SJens Axboe } 1032b92ce558SJens Axboe 1033b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1034b92ce558SJens Axboe 1035b92ce558SJens Axboe return bytes; 1036b92ce558SJens Axboe 1037b92ce558SJens Axboe out_release: 1038b92ce558SJens Axboe /* 1039b92ce558SJens Axboe * If we did an incomplete transfer we must release 1040b92ce558SJens Axboe * the pipe buffers in question: 1041b92ce558SJens Axboe */ 1042b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1043b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1044b92ce558SJens Axboe 1045b92ce558SJens Axboe if (buf->ops) { 1046b92ce558SJens Axboe buf->ops->release(pipe, buf); 1047b92ce558SJens Axboe buf->ops = NULL; 1048b92ce558SJens Axboe } 1049b92ce558SJens Axboe } 1050b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1051b92ce558SJens Axboe 1052b92ce558SJens Axboe /* 1053b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1054b92ce558SJens Axboe */ 1055b92ce558SJens Axboe if (bytes > 0) 1056b92ce558SJens Axboe return bytes; 1057b92ce558SJens Axboe 1058b92ce558SJens Axboe return ret; 1059b92ce558SJens Axboe } 1060b92ce558SJens Axboe 1061b92ce558SJens Axboe EXPORT_SYMBOL(do_splice_direct); 1062b92ce558SJens Axboe 106383f9135bSJens Axboe /* 1064ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1065ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1066ddac0d39SJens Axboe * pipe. 1067ddac0d39SJens Axboe */ 1068ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1069ddac0d39SJens Axboe { 1070ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1071ddac0d39SJens Axboe return inode->i_pipe; 1072ddac0d39SJens Axboe 1073ddac0d39SJens Axboe return NULL; 1074ddac0d39SJens Axboe } 1075ddac0d39SJens Axboe 1076ddac0d39SJens Axboe /* 107783f9135bSJens Axboe * Determine where to splice to/from. 107883f9135bSJens Axboe */ 1079529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1080529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1081529565dcSIngo Molnar size_t len, unsigned int flags) 10825274f052SJens Axboe { 10833a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1084cbb7e577SJens Axboe loff_t offset, *off; 1085a4514ebdSJens Axboe long ret; 10865274f052SJens Axboe 10870f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1088529565dcSIngo Molnar if (pipe) { 1089529565dcSIngo Molnar if (off_in) 1090529565dcSIngo Molnar return -ESPIPE; 1091b92ce558SJens Axboe if (off_out) { 1092b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1093b92ce558SJens Axboe return -EINVAL; 1094cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1095b92ce558SJens Axboe return -EFAULT; 1096cbb7e577SJens Axboe off = &offset; 1097cbb7e577SJens Axboe } else 1098cbb7e577SJens Axboe off = &out->f_pos; 1099529565dcSIngo Molnar 1100a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1101a4514ebdSJens Axboe 1102a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1103a4514ebdSJens Axboe ret = -EFAULT; 1104a4514ebdSJens Axboe 1105a4514ebdSJens Axboe return ret; 1106529565dcSIngo Molnar } 11075274f052SJens Axboe 11080f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1109529565dcSIngo Molnar if (pipe) { 1110529565dcSIngo Molnar if (off_out) 1111529565dcSIngo Molnar return -ESPIPE; 1112b92ce558SJens Axboe if (off_in) { 1113b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1114b92ce558SJens Axboe return -EINVAL; 1115cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1116b92ce558SJens Axboe return -EFAULT; 1117cbb7e577SJens Axboe off = &offset; 1118cbb7e577SJens Axboe } else 1119cbb7e577SJens Axboe off = &in->f_pos; 1120529565dcSIngo Molnar 1121a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1122a4514ebdSJens Axboe 1123a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1124a4514ebdSJens Axboe ret = -EFAULT; 1125a4514ebdSJens Axboe 1126a4514ebdSJens Axboe return ret; 1127529565dcSIngo Molnar } 11285274f052SJens Axboe 11295274f052SJens Axboe return -EINVAL; 11305274f052SJens Axboe } 11315274f052SJens Axboe 1132912d35f8SJens Axboe /* 1133912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1134912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1135912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1136912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1137912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1138912d35f8SJens Axboe */ 1139912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1140912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 11417afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1142912d35f8SJens Axboe { 1143912d35f8SJens Axboe int buffers = 0, error = 0; 1144912d35f8SJens Axboe 1145912d35f8SJens Axboe /* 1146912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1147912d35f8SJens Axboe * across a "get_user()". 1148912d35f8SJens Axboe */ 1149912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1150912d35f8SJens Axboe 1151912d35f8SJens Axboe while (nr_vecs) { 1152912d35f8SJens Axboe unsigned long off, npages; 1153912d35f8SJens Axboe void __user *base; 1154912d35f8SJens Axboe size_t len; 1155912d35f8SJens Axboe int i; 1156912d35f8SJens Axboe 1157912d35f8SJens Axboe /* 1158912d35f8SJens Axboe * Get user address base and length for this iovec. 1159912d35f8SJens Axboe */ 1160912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1161912d35f8SJens Axboe if (unlikely(error)) 1162912d35f8SJens Axboe break; 1163912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1164912d35f8SJens Axboe if (unlikely(error)) 1165912d35f8SJens Axboe break; 1166912d35f8SJens Axboe 1167912d35f8SJens Axboe /* 1168912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1169912d35f8SJens Axboe */ 1170912d35f8SJens Axboe if (unlikely(!len)) 1171912d35f8SJens Axboe break; 1172912d35f8SJens Axboe error = -EFAULT; 1173912d35f8SJens Axboe if (unlikely(!base)) 1174912d35f8SJens Axboe break; 1175912d35f8SJens Axboe 1176912d35f8SJens Axboe /* 1177912d35f8SJens Axboe * Get this base offset and number of pages, then map 1178912d35f8SJens Axboe * in the user pages. 1179912d35f8SJens Axboe */ 1180912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 11817afa6fd0SJens Axboe 11827afa6fd0SJens Axboe /* 11837afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 11847afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 11857afa6fd0SJens Axboe */ 11867afa6fd0SJens Axboe error = -EINVAL; 11877afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 11887afa6fd0SJens Axboe break; 11897afa6fd0SJens Axboe 1190912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1191912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1192912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1193912d35f8SJens Axboe 1194912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1195912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1196912d35f8SJens Axboe &pages[buffers], NULL); 1197912d35f8SJens Axboe 1198912d35f8SJens Axboe if (unlikely(error <= 0)) 1199912d35f8SJens Axboe break; 1200912d35f8SJens Axboe 1201912d35f8SJens Axboe /* 1202912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1203912d35f8SJens Axboe */ 1204912d35f8SJens Axboe for (i = 0; i < error; i++) { 12057591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1206912d35f8SJens Axboe 1207912d35f8SJens Axboe partial[buffers].offset = off; 1208912d35f8SJens Axboe partial[buffers].len = plen; 1209912d35f8SJens Axboe 1210912d35f8SJens Axboe off = 0; 1211912d35f8SJens Axboe len -= plen; 1212912d35f8SJens Axboe buffers++; 1213912d35f8SJens Axboe } 1214912d35f8SJens Axboe 1215912d35f8SJens Axboe /* 1216912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1217912d35f8SJens Axboe * means we have to move some of this into a pipe to 1218912d35f8SJens Axboe * be able to continue. 1219912d35f8SJens Axboe */ 1220912d35f8SJens Axboe if (len) 1221912d35f8SJens Axboe break; 1222912d35f8SJens Axboe 1223912d35f8SJens Axboe /* 1224912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1225912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1226912d35f8SJens Axboe * room for. 1227912d35f8SJens Axboe */ 1228912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1229912d35f8SJens Axboe break; 1230912d35f8SJens Axboe 1231912d35f8SJens Axboe nr_vecs--; 1232912d35f8SJens Axboe iov++; 1233912d35f8SJens Axboe } 1234912d35f8SJens Axboe 1235912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1236912d35f8SJens Axboe 1237912d35f8SJens Axboe if (buffers) 1238912d35f8SJens Axboe return buffers; 1239912d35f8SJens Axboe 1240912d35f8SJens Axboe return error; 1241912d35f8SJens Axboe } 1242912d35f8SJens Axboe 1243912d35f8SJens Axboe /* 1244912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1245912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1246912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1247912d35f8SJens Axboe * 1248912d35f8SJens Axboe * Note that vmsplice only supports splicing _from_ user memory to a pipe, 1249912d35f8SJens Axboe * not the other way around. Splicing from user memory is a simple operation 1250912d35f8SJens Axboe * that can be supported without any funky alignment restrictions or nasty 1251912d35f8SJens Axboe * vm tricks. We simply map in the user memory and fill them into a pipe. 1252912d35f8SJens Axboe * The reverse isn't quite as easy, though. There are two possible solutions 1253912d35f8SJens Axboe * for that: 1254912d35f8SJens Axboe * 1255912d35f8SJens Axboe * - memcpy() the data internally, at which point we might as well just 1256912d35f8SJens Axboe * do a regular read() on the buffer anyway. 1257912d35f8SJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 1258912d35f8SJens Axboe * has restriction limitations on both ends of the pipe). 1259912d35f8SJens Axboe * 1260912d35f8SJens Axboe * Alas, it isn't here. 1261912d35f8SJens Axboe * 1262912d35f8SJens Axboe */ 1263912d35f8SJens Axboe static long do_vmsplice(struct file *file, const struct iovec __user *iov, 1264912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1265912d35f8SJens Axboe { 1266ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1267912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1268912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1269912d35f8SJens Axboe struct splice_pipe_desc spd = { 1270912d35f8SJens Axboe .pages = pages, 1271912d35f8SJens Axboe .partial = partial, 1272912d35f8SJens Axboe .flags = flags, 1273912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1274912d35f8SJens Axboe }; 1275912d35f8SJens Axboe 12760f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1277ddac0d39SJens Axboe if (!pipe) 1278912d35f8SJens Axboe return -EBADF; 1279912d35f8SJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 1280912d35f8SJens Axboe return -EINVAL; 1281912d35f8SJens Axboe else if (unlikely(!nr_segs)) 1282912d35f8SJens Axboe return 0; 1283912d35f8SJens Axboe 12847afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 12857afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1286912d35f8SJens Axboe if (spd.nr_pages <= 0) 1287912d35f8SJens Axboe return spd.nr_pages; 1288912d35f8SJens Axboe 128900522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1290912d35f8SJens Axboe } 1291912d35f8SJens Axboe 1292912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1293912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1294912d35f8SJens Axboe { 1295912d35f8SJens Axboe struct file *file; 1296912d35f8SJens Axboe long error; 1297912d35f8SJens Axboe int fput; 1298912d35f8SJens Axboe 1299912d35f8SJens Axboe error = -EBADF; 1300912d35f8SJens Axboe file = fget_light(fd, &fput); 1301912d35f8SJens Axboe if (file) { 1302912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 1303912d35f8SJens Axboe error = do_vmsplice(file, iov, nr_segs, flags); 1304912d35f8SJens Axboe 1305912d35f8SJens Axboe fput_light(file, fput); 1306912d35f8SJens Axboe } 1307912d35f8SJens Axboe 1308912d35f8SJens Axboe return error; 1309912d35f8SJens Axboe } 1310912d35f8SJens Axboe 1311529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1312529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1313529565dcSIngo Molnar size_t len, unsigned int flags) 13145274f052SJens Axboe { 13155274f052SJens Axboe long error; 13165274f052SJens Axboe struct file *in, *out; 13175274f052SJens Axboe int fput_in, fput_out; 13185274f052SJens Axboe 13195274f052SJens Axboe if (unlikely(!len)) 13205274f052SJens Axboe return 0; 13215274f052SJens Axboe 13225274f052SJens Axboe error = -EBADF; 1323529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 13245274f052SJens Axboe if (in) { 13255274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1326529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 13275274f052SJens Axboe if (out) { 13285274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1329529565dcSIngo Molnar error = do_splice(in, off_in, 1330529565dcSIngo Molnar out, off_out, 1331529565dcSIngo Molnar len, flags); 13325274f052SJens Axboe fput_light(out, fput_out); 13335274f052SJens Axboe } 13345274f052SJens Axboe } 13355274f052SJens Axboe 13365274f052SJens Axboe fput_light(in, fput_in); 13375274f052SJens Axboe } 13385274f052SJens Axboe 13395274f052SJens Axboe return error; 13405274f052SJens Axboe } 134170524490SJens Axboe 134270524490SJens Axboe /* 1343aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1344aadd06e5SJens Axboe * return an appropriate error. 1345aadd06e5SJens Axboe */ 1346aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1347aadd06e5SJens Axboe { 1348aadd06e5SJens Axboe int ret; 1349aadd06e5SJens Axboe 1350aadd06e5SJens Axboe /* 1351aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1352aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1353aadd06e5SJens Axboe */ 1354aadd06e5SJens Axboe if (pipe->nrbufs) 1355aadd06e5SJens Axboe return 0; 1356aadd06e5SJens Axboe 1357aadd06e5SJens Axboe ret = 0; 1358aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1359aadd06e5SJens Axboe 1360aadd06e5SJens Axboe while (!pipe->nrbufs) { 1361aadd06e5SJens Axboe if (signal_pending(current)) { 1362aadd06e5SJens Axboe ret = -ERESTARTSYS; 1363aadd06e5SJens Axboe break; 1364aadd06e5SJens Axboe } 1365aadd06e5SJens Axboe if (!pipe->writers) 1366aadd06e5SJens Axboe break; 1367aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1368aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1369aadd06e5SJens Axboe ret = -EAGAIN; 1370aadd06e5SJens Axboe break; 1371aadd06e5SJens Axboe } 1372aadd06e5SJens Axboe } 1373aadd06e5SJens Axboe pipe_wait(pipe); 1374aadd06e5SJens Axboe } 1375aadd06e5SJens Axboe 1376aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1377aadd06e5SJens Axboe return ret; 1378aadd06e5SJens Axboe } 1379aadd06e5SJens Axboe 1380aadd06e5SJens Axboe /* 1381aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1382aadd06e5SJens Axboe * return an appropriate error. 1383aadd06e5SJens Axboe */ 1384aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1385aadd06e5SJens Axboe { 1386aadd06e5SJens Axboe int ret; 1387aadd06e5SJens Axboe 1388aadd06e5SJens Axboe /* 1389aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1390aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1391aadd06e5SJens Axboe */ 1392aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1393aadd06e5SJens Axboe return 0; 1394aadd06e5SJens Axboe 1395aadd06e5SJens Axboe ret = 0; 1396aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1397aadd06e5SJens Axboe 1398aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1399aadd06e5SJens Axboe if (!pipe->readers) { 1400aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1401aadd06e5SJens Axboe ret = -EPIPE; 1402aadd06e5SJens Axboe break; 1403aadd06e5SJens Axboe } 1404aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1405aadd06e5SJens Axboe ret = -EAGAIN; 1406aadd06e5SJens Axboe break; 1407aadd06e5SJens Axboe } 1408aadd06e5SJens Axboe if (signal_pending(current)) { 1409aadd06e5SJens Axboe ret = -ERESTARTSYS; 1410aadd06e5SJens Axboe break; 1411aadd06e5SJens Axboe } 1412aadd06e5SJens Axboe pipe->waiting_writers++; 1413aadd06e5SJens Axboe pipe_wait(pipe); 1414aadd06e5SJens Axboe pipe->waiting_writers--; 1415aadd06e5SJens Axboe } 1416aadd06e5SJens Axboe 1417aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1418aadd06e5SJens Axboe return ret; 1419aadd06e5SJens Axboe } 1420aadd06e5SJens Axboe 1421aadd06e5SJens Axboe /* 142270524490SJens Axboe * Link contents of ipipe to opipe. 142370524490SJens Axboe */ 142470524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 142570524490SJens Axboe struct pipe_inode_info *opipe, 142670524490SJens Axboe size_t len, unsigned int flags) 142770524490SJens Axboe { 142870524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1429aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 143070524490SJens Axboe 143170524490SJens Axboe /* 143270524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 143370524490SJens Axboe * grabbing by inode address. Otherwise two different processes 143470524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 143570524490SJens Axboe */ 143662752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 143770524490SJens Axboe 1438aadd06e5SJens Axboe do { 143970524490SJens Axboe if (!opipe->readers) { 144070524490SJens Axboe send_sig(SIGPIPE, current, 0); 144170524490SJens Axboe if (!ret) 144270524490SJens Axboe ret = -EPIPE; 144370524490SJens Axboe break; 144470524490SJens Axboe } 144570524490SJens Axboe 144670524490SJens Axboe /* 1447aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1448aadd06e5SJens Axboe * output room, break. 144970524490SJens Axboe */ 1450aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1451aadd06e5SJens Axboe break; 1452aadd06e5SJens Axboe 1453aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1454aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 145570524490SJens Axboe 145670524490SJens Axboe /* 145770524490SJens Axboe * Get a reference to this pipe buffer, 145870524490SJens Axboe * so we can copy the contents over. 145970524490SJens Axboe */ 146070524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 146170524490SJens Axboe 146270524490SJens Axboe obuf = opipe->bufs + nbuf; 146370524490SJens Axboe *obuf = *ibuf; 146470524490SJens Axboe 14657afa6fd0SJens Axboe /* 14667afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 14677afa6fd0SJens Axboe * prevent multiple steals of this page. 14687afa6fd0SJens Axboe */ 14697afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 14707afa6fd0SJens Axboe 147170524490SJens Axboe if (obuf->len > len) 147270524490SJens Axboe obuf->len = len; 147370524490SJens Axboe 147470524490SJens Axboe opipe->nrbufs++; 147570524490SJens Axboe ret += obuf->len; 147670524490SJens Axboe len -= obuf->len; 1477aadd06e5SJens Axboe i++; 1478aadd06e5SJens Axboe } while (len); 147970524490SJens Axboe 148062752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 148170524490SJens Axboe 1482aadd06e5SJens Axboe /* 1483aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1484aadd06e5SJens Axboe */ 1485aadd06e5SJens Axboe if (ret > 0) { 148670524490SJens Axboe smp_mb(); 148770524490SJens Axboe if (waitqueue_active(&opipe->wait)) 148870524490SJens Axboe wake_up_interruptible(&opipe->wait); 148970524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 149070524490SJens Axboe } 149170524490SJens Axboe 149270524490SJens Axboe return ret; 149370524490SJens Axboe } 149470524490SJens Axboe 149570524490SJens Axboe /* 149670524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 149770524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 149870524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 149970524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 150070524490SJens Axboe */ 150170524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 150270524490SJens Axboe unsigned int flags) 150370524490SJens Axboe { 15040f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 15050f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1506aadd06e5SJens Axboe int ret = -EINVAL; 150770524490SJens Axboe 150870524490SJens Axboe /* 1509aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1510aadd06e5SJens Axboe * copying the data. 151170524490SJens Axboe */ 1512aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1513aadd06e5SJens Axboe /* 1514aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1515aadd06e5SJens Axboe * ordering doesn't really matter. 1516aadd06e5SJens Axboe */ 1517aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1518aadd06e5SJens Axboe if (!ret) { 1519aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 1520aadd06e5SJens Axboe if (!ret) { 1521aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1522aadd06e5SJens Axboe if (!ret && (flags & SPLICE_F_NONBLOCK)) 1523aadd06e5SJens Axboe ret = -EAGAIN; 1524aadd06e5SJens Axboe } 1525aadd06e5SJens Axboe } 1526aadd06e5SJens Axboe } 152770524490SJens Axboe 1528aadd06e5SJens Axboe return ret; 152970524490SJens Axboe } 153070524490SJens Axboe 153170524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 153270524490SJens Axboe { 153370524490SJens Axboe struct file *in; 153470524490SJens Axboe int error, fput_in; 153570524490SJens Axboe 153670524490SJens Axboe if (unlikely(!len)) 153770524490SJens Axboe return 0; 153870524490SJens Axboe 153970524490SJens Axboe error = -EBADF; 154070524490SJens Axboe in = fget_light(fdin, &fput_in); 154170524490SJens Axboe if (in) { 154270524490SJens Axboe if (in->f_mode & FMODE_READ) { 154370524490SJens Axboe int fput_out; 154470524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 154570524490SJens Axboe 154670524490SJens Axboe if (out) { 154770524490SJens Axboe if (out->f_mode & FMODE_WRITE) 154870524490SJens Axboe error = do_tee(in, out, len, flags); 154970524490SJens Axboe fput_light(out, fput_out); 155070524490SJens Axboe } 155170524490SJens Axboe } 155270524490SJens Axboe fput_light(in, fput_in); 155370524490SJens Axboe } 155470524490SJens Axboe 155570524490SJens Axboe return error; 155670524490SJens Axboe } 1557