15274f052SJens Axboe /* 25274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 35274f052SJens Axboe * 45274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 55274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 65274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 75274f052SJens Axboe * 85274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 95274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 105274f052SJens Axboe * 115274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 12c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 13c2058e06SJens Axboe * fixing lots of bugs. 145274f052SJens Axboe * 150fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 16c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 17c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 185274f052SJens Axboe * 195274f052SJens Axboe */ 205274f052SJens Axboe #include <linux/fs.h> 215274f052SJens Axboe #include <linux/file.h> 225274f052SJens Axboe #include <linux/pagemap.h> 23d6b29d7cSJens Axboe #include <linux/splice.h> 245274f052SJens Axboe #include <linux/mm_inline.h> 255abc97aaSJens Axboe #include <linux/swap.h> 264f6f0bd2SJens Axboe #include <linux/writeback.h> 274f6f0bd2SJens Axboe #include <linux/buffer_head.h> 28a0f06780SJeff Garzik #include <linux/module.h> 294f6f0bd2SJens Axboe #include <linux/syscalls.h> 30912d35f8SJens Axboe #include <linux/uio.h> 3129ce2058SJames Morris #include <linux/security.h> 325274f052SJens Axboe 3383f9135bSJens Axboe /* 3483f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3583f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 3683f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 3783f9135bSJens Axboe * attempt to reuse this page for another destination. 3883f9135bSJens Axboe */ 3976ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 405abc97aaSJens Axboe struct pipe_buffer *buf) 415abc97aaSJens Axboe { 425abc97aaSJens Axboe struct page *page = buf->page; 439e94cd4fSJens Axboe struct address_space *mapping; 445abc97aaSJens Axboe 459e0267c2SJens Axboe lock_page(page); 469e0267c2SJens Axboe 479e94cd4fSJens Axboe mapping = page_mapping(page); 489e94cd4fSJens Axboe if (mapping) { 495abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 505abc97aaSJens Axboe 51ad8d6f0aSJens Axboe /* 529e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 539e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 549e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 559e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 569e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 579e94cd4fSJens Axboe * ensues. 58ad8d6f0aSJens Axboe */ 59ad8d6f0aSJens Axboe wait_on_page_writeback(page); 60ad8d6f0aSJens Axboe 614f6f0bd2SJens Axboe if (PagePrivate(page)) 622ae88149SNick Piggin try_to_release_page(page, GFP_KERNEL); 634f6f0bd2SJens Axboe 649e94cd4fSJens Axboe /* 659e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 669e94cd4fSJens Axboe * and return good. 679e94cd4fSJens Axboe */ 689e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 691432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 705abc97aaSJens Axboe return 0; 715abc97aaSJens Axboe } 729e94cd4fSJens Axboe } 739e94cd4fSJens Axboe 749e94cd4fSJens Axboe /* 759e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 769e94cd4fSJens Axboe * address space, unlock and return failure. 779e94cd4fSJens Axboe */ 789e94cd4fSJens Axboe unlock_page(page); 799e94cd4fSJens Axboe return 1; 809e94cd4fSJens Axboe } 815abc97aaSJens Axboe 8276ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 835274f052SJens Axboe struct pipe_buffer *buf) 845274f052SJens Axboe { 855274f052SJens Axboe page_cache_release(buf->page); 861432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 875274f052SJens Axboe } 885274f052SJens Axboe 890845718dSJens Axboe /* 900845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 910845718dSJens Axboe * is a page cache page, IO may be in flight. 920845718dSJens Axboe */ 93cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 945274f052SJens Axboe struct pipe_buffer *buf) 955274f052SJens Axboe { 965274f052SJens Axboe struct page *page = buf->page; 9749d0b21bSJens Axboe int err; 985274f052SJens Axboe 995274f052SJens Axboe if (!PageUptodate(page)) { 10049d0b21bSJens Axboe lock_page(page); 1015274f052SJens Axboe 10249d0b21bSJens Axboe /* 10349d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10473d62d83SIngo Molnar * splice, if this is the first page. 10549d0b21bSJens Axboe */ 1065274f052SJens Axboe if (!page->mapping) { 10749d0b21bSJens Axboe err = -ENODATA; 10849d0b21bSJens Axboe goto error; 1095274f052SJens Axboe } 1105274f052SJens Axboe 11149d0b21bSJens Axboe /* 11273d62d83SIngo Molnar * Uh oh, read-error from disk. 11349d0b21bSJens Axboe */ 11449d0b21bSJens Axboe if (!PageUptodate(page)) { 11549d0b21bSJens Axboe err = -EIO; 11649d0b21bSJens Axboe goto error; 11749d0b21bSJens Axboe } 11849d0b21bSJens Axboe 11949d0b21bSJens Axboe /* 120f84d7519SJens Axboe * Page is ok afterall, we are done. 12149d0b21bSJens Axboe */ 12249d0b21bSJens Axboe unlock_page(page); 12349d0b21bSJens Axboe } 12449d0b21bSJens Axboe 125f84d7519SJens Axboe return 0; 12649d0b21bSJens Axboe error: 12749d0b21bSJens Axboe unlock_page(page); 128f84d7519SJens Axboe return err; 12970524490SJens Axboe } 13070524490SJens Axboe 131d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1325274f052SJens Axboe .can_merge = 0, 133f84d7519SJens Axboe .map = generic_pipe_buf_map, 134f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 135cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1365274f052SJens Axboe .release = page_cache_pipe_buf_release, 1375abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 138f84d7519SJens Axboe .get = generic_pipe_buf_get, 1395274f052SJens Axboe }; 1405274f052SJens Axboe 141912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 142912d35f8SJens Axboe struct pipe_buffer *buf) 143912d35f8SJens Axboe { 1447afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 145912d35f8SJens Axboe return 1; 1467afa6fd0SJens Axboe 1471432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 148330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 149912d35f8SJens Axboe } 150912d35f8SJens Axboe 151d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 152912d35f8SJens Axboe .can_merge = 0, 153f84d7519SJens Axboe .map = generic_pipe_buf_map, 154f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 155cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 156912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 157912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 158f84d7519SJens Axboe .get = generic_pipe_buf_get, 159912d35f8SJens Axboe }; 160912d35f8SJens Axboe 161932cc6d4SJens Axboe /** 162932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 163932cc6d4SJens Axboe * @pipe: pipe to fill 164932cc6d4SJens Axboe * @spd: data to fill 165932cc6d4SJens Axboe * 166932cc6d4SJens Axboe * Description: 16779685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 168932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 169932cc6d4SJens Axboe * function will link that data to the pipe. 170932cc6d4SJens Axboe * 17183f9135bSJens Axboe */ 172d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 173912d35f8SJens Axboe struct splice_pipe_desc *spd) 1745274f052SJens Axboe { 17500de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 176912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1775274f052SJens Axboe 1785274f052SJens Axboe ret = 0; 1795274f052SJens Axboe do_wakeup = 0; 180912d35f8SJens Axboe page_nr = 0; 1815274f052SJens Axboe 1823a326a2cSIngo Molnar if (pipe->inode) 1833a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1845274f052SJens Axboe 1855274f052SJens Axboe for (;;) { 1863a326a2cSIngo Molnar if (!pipe->readers) { 1875274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1885274f052SJens Axboe if (!ret) 1895274f052SJens Axboe ret = -EPIPE; 1905274f052SJens Axboe break; 1915274f052SJens Axboe } 1925274f052SJens Axboe 1936f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1946f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1953a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1965274f052SJens Axboe 197912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 198912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 199912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 200497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 201912d35f8SJens Axboe buf->ops = spd->ops; 2027afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2037afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2047afa6fd0SJens Axboe 2056f767b04SJens Axboe pipe->nrbufs++; 206912d35f8SJens Axboe page_nr++; 207912d35f8SJens Axboe ret += buf->len; 208912d35f8SJens Axboe 2096f767b04SJens Axboe if (pipe->inode) 2105274f052SJens Axboe do_wakeup = 1; 2115274f052SJens Axboe 212912d35f8SJens Axboe if (!--spd->nr_pages) 2135274f052SJens Axboe break; 2146f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2155274f052SJens Axboe continue; 2165274f052SJens Axboe 2175274f052SJens Axboe break; 2185274f052SJens Axboe } 2195274f052SJens Axboe 220912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22129e35094SLinus Torvalds if (!ret) 22229e35094SLinus Torvalds ret = -EAGAIN; 22329e35094SLinus Torvalds break; 22429e35094SLinus Torvalds } 22529e35094SLinus Torvalds 2265274f052SJens Axboe if (signal_pending(current)) { 2275274f052SJens Axboe if (!ret) 2285274f052SJens Axboe ret = -ERESTARTSYS; 2295274f052SJens Axboe break; 2305274f052SJens Axboe } 2315274f052SJens Axboe 2325274f052SJens Axboe if (do_wakeup) { 233c0bd1f65SJens Axboe smp_mb(); 2343a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2353a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2363a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2375274f052SJens Axboe do_wakeup = 0; 2385274f052SJens Axboe } 2395274f052SJens Axboe 2403a326a2cSIngo Molnar pipe->waiting_writers++; 2413a326a2cSIngo Molnar pipe_wait(pipe); 2423a326a2cSIngo Molnar pipe->waiting_writers--; 2435274f052SJens Axboe } 2445274f052SJens Axboe 24502676e5aSJens Axboe if (pipe->inode) { 2463a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2475274f052SJens Axboe 2485274f052SJens Axboe if (do_wakeup) { 249c0bd1f65SJens Axboe smp_mb(); 2503a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2513a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2523a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2535274f052SJens Axboe } 25402676e5aSJens Axboe } 2555274f052SJens Axboe 25600de00bdSJens Axboe while (page_nr < spd_pages) 257912d35f8SJens Axboe page_cache_release(spd->pages[page_nr++]); 2585274f052SJens Axboe 2595274f052SJens Axboe return ret; 2605274f052SJens Axboe } 2615274f052SJens Axboe 2623a326a2cSIngo Molnar static int 263cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 264cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 265cbb7e577SJens Axboe unsigned int flags) 2665274f052SJens Axboe { 2675274f052SJens Axboe struct address_space *mapping = in->f_mapping; 268d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 26916c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 270912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2715274f052SJens Axboe struct page *page; 27291ad66efSJens Axboe pgoff_t index, end_index; 27391ad66efSJens Axboe loff_t isize; 274eb20796bSJens Axboe int error, page_nr; 275912d35f8SJens Axboe struct splice_pipe_desc spd = { 276912d35f8SJens Axboe .pages = pages, 277912d35f8SJens Axboe .partial = partial, 278912d35f8SJens Axboe .flags = flags, 279912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 280912d35f8SJens Axboe }; 2815274f052SJens Axboe 282cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 283912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 284d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 285d8983910SFengguang Wu nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); 2865274f052SJens Axboe 2875274f052SJens Axboe /* 288eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 28982aa5d61SJens Axboe */ 290eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 291431a4820SFengguang Wu index += spd.nr_pages; 292eb20796bSJens Axboe 2935274f052SJens Axboe /* 294eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 295431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 296eb20796bSJens Axboe */ 297431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 298cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 299cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 300431a4820SFengguang Wu 301932cc6d4SJens Axboe error = 0; 302eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 303eb20796bSJens Axboe /* 304eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 305eb20796bSJens Axboe * the first hole. 3065274f052SJens Axboe */ 3077480a904SJens Axboe page = find_get_page(mapping, index); 3087480a904SJens Axboe if (!page) { 309e27dedd8SJens Axboe /* 310eb20796bSJens Axboe * page didn't exist, allocate one. 3117480a904SJens Axboe */ 3127480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3135274f052SJens Axboe if (!page) 3145274f052SJens Axboe break; 3155274f052SJens Axboe 3167480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3172ae88149SNick Piggin GFP_KERNEL); 3185274f052SJens Axboe if (unlikely(error)) { 3195274f052SJens Axboe page_cache_release(page); 320a0548871SJens Axboe if (error == -EEXIST) 321a0548871SJens Axboe continue; 3225274f052SJens Axboe break; 3235274f052SJens Axboe } 324eb20796bSJens Axboe /* 325eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 326eb20796bSJens Axboe * to avoid convoluting the logic below even more. 327eb20796bSJens Axboe */ 328eb20796bSJens Axboe unlock_page(page); 3295274f052SJens Axboe } 3307480a904SJens Axboe 331eb20796bSJens Axboe pages[spd.nr_pages++] = page; 332eb20796bSJens Axboe index++; 333eb20796bSJens Axboe } 334eb20796bSJens Axboe 335eb20796bSJens Axboe /* 336eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 337eb20796bSJens Axboe * pages, fill in the partial map, etc. 338eb20796bSJens Axboe */ 339eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 340eb20796bSJens Axboe nr_pages = spd.nr_pages; 341eb20796bSJens Axboe spd.nr_pages = 0; 342eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 343eb20796bSJens Axboe unsigned int this_len; 344eb20796bSJens Axboe 345eb20796bSJens Axboe if (!len) 346eb20796bSJens Axboe break; 347eb20796bSJens Axboe 348eb20796bSJens Axboe /* 349eb20796bSJens Axboe * this_len is the max we'll use from this page 350eb20796bSJens Axboe */ 351eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 352eb20796bSJens Axboe page = pages[page_nr]; 353eb20796bSJens Axboe 354a08a166fSFengguang Wu if (PageReadahead(page)) 355cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 356d8983910SFengguang Wu page, index, req_pages - page_nr); 357a08a166fSFengguang Wu 3587480a904SJens Axboe /* 3597480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3607480a904SJens Axboe */ 3617480a904SJens Axboe if (!PageUptodate(page)) { 362c4f895cbSJens Axboe /* 363c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 364c4f895cbSJens Axboe * for an in-flight io page 365c4f895cbSJens Axboe */ 3669ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3679ae9d68cSFengguang Wu if (TestSetPageLocked(page)) 368c4f895cbSJens Axboe break; 3699ae9d68cSFengguang Wu } else 3707480a904SJens Axboe lock_page(page); 3717480a904SJens Axboe 3727480a904SJens Axboe /* 3737480a904SJens Axboe * page was truncated, stop here. if this isn't the 3747480a904SJens Axboe * first page, we'll just complete what we already 3757480a904SJens Axboe * added 3767480a904SJens Axboe */ 3777480a904SJens Axboe if (!page->mapping) { 3787480a904SJens Axboe unlock_page(page); 3797480a904SJens Axboe break; 3807480a904SJens Axboe } 3817480a904SJens Axboe /* 3827480a904SJens Axboe * page was already under io and is now done, great 3837480a904SJens Axboe */ 3847480a904SJens Axboe if (PageUptodate(page)) { 3857480a904SJens Axboe unlock_page(page); 3867480a904SJens Axboe goto fill_it; 3877480a904SJens Axboe } 3887480a904SJens Axboe 3897480a904SJens Axboe /* 3907480a904SJens Axboe * need to read in the page 3917480a904SJens Axboe */ 3927480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 3937480a904SJens Axboe if (unlikely(error)) { 394eb20796bSJens Axboe /* 395eb20796bSJens Axboe * We really should re-lookup the page here, 396eb20796bSJens Axboe * but it complicates things a lot. Instead 397eb20796bSJens Axboe * lets just do what we already stored, and 398eb20796bSJens Axboe * we'll get it the next time we are called. 399eb20796bSJens Axboe */ 4007480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 401eb20796bSJens Axboe error = 0; 402eb20796bSJens Axboe 4037480a904SJens Axboe break; 4047480a904SJens Axboe } 405620a324bSJens Axboe } 406620a324bSJens Axboe fill_it: 40791ad66efSJens Axboe /* 408620a324bSJens Axboe * i_size must be checked after PageUptodate. 40991ad66efSJens Axboe */ 41091ad66efSJens Axboe isize = i_size_read(mapping->host); 41191ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 412eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 41391ad66efSJens Axboe break; 41491ad66efSJens Axboe 41591ad66efSJens Axboe /* 41691ad66efSJens Axboe * if this is the last page, see if we need to shrink 41791ad66efSJens Axboe * the length and stop 41891ad66efSJens Axboe */ 41991ad66efSJens Axboe if (end_index == index) { 420475ecadeSHugh Dickins unsigned int plen; 421475ecadeSHugh Dickins 422475ecadeSHugh Dickins /* 423475ecadeSHugh Dickins * max good bytes in this page 424475ecadeSHugh Dickins */ 425475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 426475ecadeSHugh Dickins if (plen <= loff) 42791ad66efSJens Axboe break; 428475ecadeSHugh Dickins 42991ad66efSJens Axboe /* 43091ad66efSJens Axboe * force quit after adding this page 43191ad66efSJens Axboe */ 432475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 433eb20796bSJens Axboe len = this_len; 43491ad66efSJens Axboe } 435620a324bSJens Axboe 436eb20796bSJens Axboe partial[page_nr].offset = loff; 437eb20796bSJens Axboe partial[page_nr].len = this_len; 43882aa5d61SJens Axboe len -= this_len; 43991ad66efSJens Axboe loff = 0; 440eb20796bSJens Axboe spd.nr_pages++; 441eb20796bSJens Axboe index++; 4425274f052SJens Axboe } 4435274f052SJens Axboe 444eb20796bSJens Axboe /* 445475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 446eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 447eb20796bSJens Axboe */ 448eb20796bSJens Axboe while (page_nr < nr_pages) 449eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 450f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 451eb20796bSJens Axboe 452912d35f8SJens Axboe if (spd.nr_pages) 45300522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 45416c523ddSJens Axboe 4557480a904SJens Axboe return error; 4565274f052SJens Axboe } 4575274f052SJens Axboe 45883f9135bSJens Axboe /** 45983f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46083f9135bSJens Axboe * @in: file to splice from 461932cc6d4SJens Axboe * @ppos: position in @in 46283f9135bSJens Axboe * @pipe: pipe to splice to 46383f9135bSJens Axboe * @len: number of bytes to splice 46483f9135bSJens Axboe * @flags: splice modifier flags 46583f9135bSJens Axboe * 466932cc6d4SJens Axboe * Description: 467932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 468932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 469932cc6d4SJens Axboe * a readpage() hook. 470932cc6d4SJens Axboe * 47183f9135bSJens Axboe */ 472cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 473cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 474cbb7e577SJens Axboe unsigned int flags) 4755274f052SJens Axboe { 4765274f052SJens Axboe ssize_t spliced; 4775274f052SJens Axboe int ret; 478d366d398SJens Axboe loff_t isize, left; 479d366d398SJens Axboe 480d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 481d366d398SJens Axboe if (unlikely(*ppos >= isize)) 482d366d398SJens Axboe return 0; 483d366d398SJens Axboe 484d366d398SJens Axboe left = isize - *ppos; 485d366d398SJens Axboe if (unlikely(left < len)) 486d366d398SJens Axboe len = left; 4875274f052SJens Axboe 4885274f052SJens Axboe ret = 0; 4895274f052SJens Axboe spliced = 0; 49051a92c0fSJens Axboe while (len && !spliced) { 491cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4925274f052SJens Axboe 493c4f895cbSJens Axboe if (ret < 0) 4945274f052SJens Axboe break; 495c4f895cbSJens Axboe else if (!ret) { 496c4f895cbSJens Axboe if (spliced) 497c4f895cbSJens Axboe break; 498c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 499c4f895cbSJens Axboe ret = -EAGAIN; 500c4f895cbSJens Axboe break; 501c4f895cbSJens Axboe } 502c4f895cbSJens Axboe } 5035274f052SJens Axboe 504cbb7e577SJens Axboe *ppos += ret; 5055274f052SJens Axboe len -= ret; 5065274f052SJens Axboe spliced += ret; 5075274f052SJens Axboe } 5085274f052SJens Axboe 5095274f052SJens Axboe if (spliced) 5105274f052SJens Axboe return spliced; 5115274f052SJens Axboe 5125274f052SJens Axboe return ret; 5135274f052SJens Axboe } 5145274f052SJens Axboe 515059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 516059a8f37SJens Axboe 5175274f052SJens Axboe /* 5184f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 519016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5205274f052SJens Axboe */ 52176ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5225274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5235274f052SJens Axboe { 5246a14b90bSJens Axboe struct file *file = sd->u.file; 5255274f052SJens Axboe loff_t pos = sd->pos; 526f84d7519SJens Axboe int ret, more; 5275274f052SJens Axboe 528cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 529f84d7519SJens Axboe if (!ret) { 530b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5315274f052SJens Axboe 532f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 533f84d7519SJens Axboe sd->len, &pos, more); 534f84d7519SJens Axboe } 5355274f052SJens Axboe 536016b661eSJens Axboe return ret; 5375274f052SJens Axboe } 5385274f052SJens Axboe 5395274f052SJens Axboe /* 5405274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5415274f052SJens Axboe * basically three cases: 5425274f052SJens Axboe * 5435274f052SJens Axboe * - Destination page already exists in the address space and there 5445274f052SJens Axboe * are users of it. For that case we have no other option that 5455274f052SJens Axboe * copying the data. Tough luck. 5465274f052SJens Axboe * - Destination page already exists in the address space, but there 5475274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5485274f052SJens Axboe * through to last case. 5495274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5505274f052SJens Axboe * the page cache and avoid the copy. 5515274f052SJens Axboe * 55283f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55383f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 55483f9135bSJens Axboe * file address space page cache. This is possible if no one else has 55583f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 55683f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 55783f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5585274f052SJens Axboe */ 55976ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5605274f052SJens Axboe struct splice_desc *sd) 5615274f052SJens Axboe { 5626a14b90bSJens Axboe struct file *file = sd->u.file; 5635274f052SJens Axboe struct address_space *mapping = file->f_mapping; 564016b661eSJens Axboe unsigned int offset, this_len; 5655274f052SJens Axboe struct page *page; 5665274f052SJens Axboe pgoff_t index; 5673e7ee3e7SJens Axboe int ret; 5685274f052SJens Axboe 5695274f052SJens Axboe /* 57049d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5715274f052SJens Axboe */ 572cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 573f84d7519SJens Axboe if (unlikely(ret)) 574f84d7519SJens Axboe return ret; 5755274f052SJens Axboe 5765274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5775274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5785274f052SJens Axboe 579016b661eSJens Axboe this_len = sd->len; 580016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 581016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 582016b661eSJens Axboe 5835274f052SJens Axboe find_page: 5849e0267c2SJens Axboe page = find_lock_page(mapping, index); 5859e0267c2SJens Axboe if (!page) { 5865274f052SJens Axboe ret = -ENOMEM; 5879e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5889e0267c2SJens Axboe if (unlikely(!page)) 589e6e80f29SJens Axboe goto out_ret; 5905274f052SJens Axboe 5915274f052SJens Axboe /* 5929e0267c2SJens Axboe * This will also lock the page 5939e0267c2SJens Axboe */ 5949e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 5952ae88149SNick Piggin GFP_KERNEL); 5969e0267c2SJens Axboe if (unlikely(ret)) 5976a860c97SJens Axboe goto out_release; 5989e0267c2SJens Axboe } 5999e0267c2SJens Axboe 600016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 601bfc4ee39SJens Axboe if (unlikely(ret)) { 602bfc4ee39SJens Axboe loff_t isize = i_size_read(mapping->host); 603bfc4ee39SJens Axboe 604bfc4ee39SJens Axboe if (ret != AOP_TRUNCATED_PAGE) 605bfc4ee39SJens Axboe unlock_page(page); 6064f6f0bd2SJens Axboe page_cache_release(page); 607bfc4ee39SJens Axboe if (ret == AOP_TRUNCATED_PAGE) 6084f6f0bd2SJens Axboe goto find_page; 609bfc4ee39SJens Axboe 610bfc4ee39SJens Axboe /* 611bfc4ee39SJens Axboe * prepare_write() may have instantiated a few blocks 612bfc4ee39SJens Axboe * outside i_size. Trim these off again. 613bfc4ee39SJens Axboe */ 614bfc4ee39SJens Axboe if (sd->pos + this_len > isize) 615bfc4ee39SJens Axboe vmtruncate(mapping->host, isize); 616bfc4ee39SJens Axboe 617e6e80f29SJens Axboe goto out_ret; 618bfc4ee39SJens Axboe } 6195274f052SJens Axboe 6200568b409SJens Axboe if (buf->page != page) { 621f84d7519SJens Axboe /* 622f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 623f84d7519SJens Axboe */ 62476ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 625f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 6265abc97aaSJens Axboe 627016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6285274f052SJens Axboe flush_dcache_page(page); 629f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 63076ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6315abc97aaSJens Axboe } 6325274f052SJens Axboe 633016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 634d9993c37SDmitriy Monakhov if (ret) { 635d9993c37SDmitriy Monakhov if (ret == AOP_TRUNCATED_PAGE) { 636d9993c37SDmitriy Monakhov page_cache_release(page); 637d9993c37SDmitriy Monakhov goto find_page; 638d9993c37SDmitriy Monakhov } 639d9993c37SDmitriy Monakhov if (ret < 0) 640d9993c37SDmitriy Monakhov goto out; 641d9993c37SDmitriy Monakhov /* 642d9993c37SDmitriy Monakhov * Partial write has happened, so 'ret' already initialized by 643d9993c37SDmitriy Monakhov * number of bytes written, Where is nothing we have to do here. 644d9993c37SDmitriy Monakhov */ 645d9993c37SDmitriy Monakhov } else 646d9993c37SDmitriy Monakhov ret = this_len; 647016b661eSJens Axboe /* 6480568b409SJens Axboe * Return the number of bytes written and mark page as 6490568b409SJens Axboe * accessed, we are now done! 650016b661eSJens Axboe */ 651c7f21e4fSJens Axboe mark_page_accessed(page); 6520568b409SJens Axboe out: 6534f6f0bd2SJens Axboe unlock_page(page); 6546a860c97SJens Axboe out_release: 6556a860c97SJens Axboe page_cache_release(page); 656e6e80f29SJens Axboe out_ret: 6575274f052SJens Axboe return ret; 6585274f052SJens Axboe } 6595274f052SJens Axboe 660932cc6d4SJens Axboe /** 661932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 662932cc6d4SJens Axboe * @pipe: pipe to splice from 663932cc6d4SJens Axboe * @sd: information to @actor 664932cc6d4SJens Axboe * @actor: handler that splices the data 665932cc6d4SJens Axboe * 666932cc6d4SJens Axboe * Description: 667932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 668932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 669932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 670932cc6d4SJens Axboe * pipe_to_user. 671932cc6d4SJens Axboe * 67283f9135bSJens Axboe */ 673c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 674c66ab6faSJens Axboe splice_actor *actor) 6755274f052SJens Axboe { 6765274f052SJens Axboe int ret, do_wakeup, err; 6775274f052SJens Axboe 6785274f052SJens Axboe ret = 0; 6795274f052SJens Axboe do_wakeup = 0; 6805274f052SJens Axboe 6815274f052SJens Axboe for (;;) { 6826f767b04SJens Axboe if (pipe->nrbufs) { 6836f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 684d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6855274f052SJens Axboe 686c66ab6faSJens Axboe sd->len = buf->len; 687c66ab6faSJens Axboe if (sd->len > sd->total_len) 688c66ab6faSJens Axboe sd->len = sd->total_len; 6895274f052SJens Axboe 690c66ab6faSJens Axboe err = actor(pipe, buf, sd); 691016b661eSJens Axboe if (err <= 0) { 6925274f052SJens Axboe if (!ret && err != -ENODATA) 6935274f052SJens Axboe ret = err; 6945274f052SJens Axboe 6955274f052SJens Axboe break; 6965274f052SJens Axboe } 6975274f052SJens Axboe 698016b661eSJens Axboe ret += err; 699016b661eSJens Axboe buf->offset += err; 700016b661eSJens Axboe buf->len -= err; 701016b661eSJens Axboe 702c66ab6faSJens Axboe sd->len -= err; 703c66ab6faSJens Axboe sd->pos += err; 704c66ab6faSJens Axboe sd->total_len -= err; 705c66ab6faSJens Axboe if (sd->len) 706016b661eSJens Axboe continue; 70773d62d83SIngo Molnar 7085274f052SJens Axboe if (!buf->len) { 7095274f052SJens Axboe buf->ops = NULL; 7103a326a2cSIngo Molnar ops->release(pipe, buf); 7116f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7126f767b04SJens Axboe pipe->nrbufs--; 7136f767b04SJens Axboe if (pipe->inode) 7145274f052SJens Axboe do_wakeup = 1; 7155274f052SJens Axboe } 7165274f052SJens Axboe 717c66ab6faSJens Axboe if (!sd->total_len) 7185274f052SJens Axboe break; 7195274f052SJens Axboe } 7205274f052SJens Axboe 7216f767b04SJens Axboe if (pipe->nrbufs) 7225274f052SJens Axboe continue; 7233a326a2cSIngo Molnar if (!pipe->writers) 7245274f052SJens Axboe break; 7253a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7265274f052SJens Axboe if (ret) 7275274f052SJens Axboe break; 7285274f052SJens Axboe } 7295274f052SJens Axboe 730c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 73129e35094SLinus Torvalds if (!ret) 73229e35094SLinus Torvalds ret = -EAGAIN; 73329e35094SLinus Torvalds break; 73429e35094SLinus Torvalds } 73529e35094SLinus Torvalds 7365274f052SJens Axboe if (signal_pending(current)) { 7375274f052SJens Axboe if (!ret) 7385274f052SJens Axboe ret = -ERESTARTSYS; 7395274f052SJens Axboe break; 7405274f052SJens Axboe } 7415274f052SJens Axboe 7425274f052SJens Axboe if (do_wakeup) { 743c0bd1f65SJens Axboe smp_mb(); 7443a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7453a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7463a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7475274f052SJens Axboe do_wakeup = 0; 7485274f052SJens Axboe } 7495274f052SJens Axboe 7503a326a2cSIngo Molnar pipe_wait(pipe); 7515274f052SJens Axboe } 7525274f052SJens Axboe 7535274f052SJens Axboe if (do_wakeup) { 754c0bd1f65SJens Axboe smp_mb(); 7553a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7563a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7573a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7585274f052SJens Axboe } 7595274f052SJens Axboe 7605274f052SJens Axboe return ret; 7615274f052SJens Axboe } 76240bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7635274f052SJens Axboe 764932cc6d4SJens Axboe /** 765932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 766932cc6d4SJens Axboe * @pipe: pipe to splice from 767932cc6d4SJens Axboe * @out: file to splice to 768932cc6d4SJens Axboe * @ppos: position in @out 769932cc6d4SJens Axboe * @len: how many bytes to splice 770932cc6d4SJens Axboe * @flags: splice modifier flags 771932cc6d4SJens Axboe * @actor: handler that splices the data 772932cc6d4SJens Axboe * 773932cc6d4SJens Axboe * Description: 774932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 775932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 776932cc6d4SJens Axboe * 777932cc6d4SJens Axboe */ 7786da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7796da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7806da61809SMark Fasheh splice_actor *actor) 7816da61809SMark Fasheh { 7826da61809SMark Fasheh ssize_t ret; 7836da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 784c66ab6faSJens Axboe struct splice_desc sd = { 785c66ab6faSJens Axboe .total_len = len, 786c66ab6faSJens Axboe .flags = flags, 787c66ab6faSJens Axboe .pos = *ppos, 7886a14b90bSJens Axboe .u.file = out, 789c66ab6faSJens Axboe }; 7906da61809SMark Fasheh 7916da61809SMark Fasheh /* 7926da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7936da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7946da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7956da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7966da61809SMark Fasheh */ 7976da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 798c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7996da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 8006da61809SMark Fasheh 8016da61809SMark Fasheh return ret; 8026da61809SMark Fasheh } 8036da61809SMark Fasheh 8046da61809SMark Fasheh /** 8056da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 8066da61809SMark Fasheh * @pipe: pipe info 8076da61809SMark Fasheh * @out: file to write to 808932cc6d4SJens Axboe * @ppos: position in @out 8096da61809SMark Fasheh * @len: number of bytes to splice 8106da61809SMark Fasheh * @flags: splice modifier flags 8116da61809SMark Fasheh * 812932cc6d4SJens Axboe * Description: 8136da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 8146da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 8156da61809SMark Fasheh * for acquiring i_mutex on both inodes. 8166da61809SMark Fasheh * 8176da61809SMark Fasheh */ 8186da61809SMark Fasheh ssize_t 8196da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 8206da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 8216da61809SMark Fasheh { 8226da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 8236da61809SMark Fasheh struct inode *inode = mapping->host; 824c66ab6faSJens Axboe struct splice_desc sd = { 825c66ab6faSJens Axboe .total_len = len, 826c66ab6faSJens Axboe .flags = flags, 827c66ab6faSJens Axboe .pos = *ppos, 8286a14b90bSJens Axboe .u.file = out, 829c66ab6faSJens Axboe }; 8306da61809SMark Fasheh ssize_t ret; 8316da61809SMark Fasheh int err; 8326da61809SMark Fasheh 8330f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 8348c34e2d6SJens Axboe if (unlikely(err)) 8358c34e2d6SJens Axboe return err; 8368c34e2d6SJens Axboe 837c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8386da61809SMark Fasheh if (ret > 0) { 83917ee4f49SJens Axboe unsigned long nr_pages; 84017ee4f49SJens Axboe 8416da61809SMark Fasheh *ppos += ret; 84217ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8436da61809SMark Fasheh 8446da61809SMark Fasheh /* 8456da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 8466da61809SMark Fasheh * sync it. 8476da61809SMark Fasheh */ 8486da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8496da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8506da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8516da61809SMark Fasheh 8526da61809SMark Fasheh if (err) 8536da61809SMark Fasheh ret = err; 8546da61809SMark Fasheh } 85517ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 8566da61809SMark Fasheh } 8576da61809SMark Fasheh 8586da61809SMark Fasheh return ret; 8596da61809SMark Fasheh } 8606da61809SMark Fasheh 8616da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8626da61809SMark Fasheh 86383f9135bSJens Axboe /** 86483f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8653a326a2cSIngo Molnar * @pipe: pipe info 86683f9135bSJens Axboe * @out: file to write to 867932cc6d4SJens Axboe * @ppos: position in @out 86883f9135bSJens Axboe * @len: number of bytes to splice 86983f9135bSJens Axboe * @flags: splice modifier flags 87083f9135bSJens Axboe * 871932cc6d4SJens Axboe * Description: 87283f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 87383f9135bSJens Axboe * the given pipe inode to the given file. 87483f9135bSJens Axboe * 87583f9135bSJens Axboe */ 8763a326a2cSIngo Molnar ssize_t 8773a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 878cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8795274f052SJens Axboe { 8804f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8818c34e2d6SJens Axboe struct inode *inode = mapping->host; 8823a326a2cSIngo Molnar ssize_t ret; 8838c34e2d6SJens Axboe int err; 8848c34e2d6SJens Axboe 8850f7fc9e4SJosef "Jeff" Sipek err = should_remove_suid(out->f_path.dentry); 8868c34e2d6SJens Axboe if (unlikely(err)) { 8878c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 8880f7fc9e4SJosef "Jeff" Sipek err = __remove_suid(out->f_path.dentry, err); 8898c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8908c34e2d6SJens Axboe if (err) 8918c34e2d6SJens Axboe return err; 8928c34e2d6SJens Axboe } 8933a326a2cSIngo Molnar 89400522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 895a4514ebdSJens Axboe if (ret > 0) { 89617ee4f49SJens Axboe unsigned long nr_pages; 89717ee4f49SJens Axboe 898a4514ebdSJens Axboe *ppos += ret; 89917ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 9004f6f0bd2SJens Axboe 9014f6f0bd2SJens Axboe /* 902a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 903a4514ebdSJens Axboe * sync it. 9044f6f0bd2SJens Axboe */ 905a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 9064f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 907a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 9084f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 9094f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 9104f6f0bd2SJens Axboe 9114f6f0bd2SJens Axboe if (err) 9124f6f0bd2SJens Axboe ret = err; 9134f6f0bd2SJens Axboe } 91417ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 915a4514ebdSJens Axboe } 9164f6f0bd2SJens Axboe 9174f6f0bd2SJens Axboe return ret; 9185274f052SJens Axboe } 9195274f052SJens Axboe 920059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 921059a8f37SJens Axboe 92283f9135bSJens Axboe /** 92383f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 924932cc6d4SJens Axboe * @pipe: pipe to splice from 92583f9135bSJens Axboe * @out: socket to write to 926932cc6d4SJens Axboe * @ppos: position in @out 92783f9135bSJens Axboe * @len: number of bytes to splice 92883f9135bSJens Axboe * @flags: splice modifier flags 92983f9135bSJens Axboe * 930932cc6d4SJens Axboe * Description: 93183f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 93283f9135bSJens Axboe * is involved. 93383f9135bSJens Axboe * 93483f9135bSJens Axboe */ 9353a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 936cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9375274f052SJens Axboe { 93800522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 9395274f052SJens Axboe } 9405274f052SJens Axboe 941059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 942a0f06780SJeff Garzik 94383f9135bSJens Axboe /* 94483f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 94583f9135bSJens Axboe */ 9463a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 947cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9485274f052SJens Axboe { 9495274f052SJens Axboe int ret; 9505274f052SJens Axboe 95149570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9525274f052SJens Axboe return -EINVAL; 9535274f052SJens Axboe 95449570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9555274f052SJens Axboe return -EBADF; 9565274f052SJens Axboe 957cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9585274f052SJens Axboe if (unlikely(ret < 0)) 9595274f052SJens Axboe return ret; 9605274f052SJens Axboe 96129ce2058SJames Morris ret = security_file_permission(out, MAY_WRITE); 96229ce2058SJames Morris if (unlikely(ret < 0)) 96329ce2058SJames Morris return ret; 96429ce2058SJames Morris 965cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9665274f052SJens Axboe } 9675274f052SJens Axboe 96883f9135bSJens Axboe /* 96983f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 97083f9135bSJens Axboe */ 971cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 972cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 973cbb7e577SJens Axboe unsigned int flags) 9745274f052SJens Axboe { 9755274f052SJens Axboe int ret; 9765274f052SJens Axboe 97749570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9785274f052SJens Axboe return -EINVAL; 9795274f052SJens Axboe 98049570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9815274f052SJens Axboe return -EBADF; 9825274f052SJens Axboe 983cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9845274f052SJens Axboe if (unlikely(ret < 0)) 9855274f052SJens Axboe return ret; 9865274f052SJens Axboe 98729ce2058SJames Morris ret = security_file_permission(in, MAY_READ); 98829ce2058SJames Morris if (unlikely(ret < 0)) 98929ce2058SJames Morris return ret; 99029ce2058SJames Morris 991cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9925274f052SJens Axboe } 9935274f052SJens Axboe 994932cc6d4SJens Axboe /** 995932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 996932cc6d4SJens Axboe * @in: file to splice from 997932cc6d4SJens Axboe * @sd: actor information on where to splice to 998932cc6d4SJens Axboe * @actor: handles the data splicing 999932cc6d4SJens Axboe * 1000932cc6d4SJens Axboe * Description: 1001932cc6d4SJens Axboe * This is a special case helper to splice directly between two 1002932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 1003932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 1004932cc6d4SJens Axboe * that process. 1005932cc6d4SJens Axboe * 1006c66ab6faSJens Axboe */ 1007c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 1008c66ab6faSJens Axboe splice_direct_actor *actor) 1009b92ce558SJens Axboe { 1010b92ce558SJens Axboe struct pipe_inode_info *pipe; 1011b92ce558SJens Axboe long ret, bytes; 1012b92ce558SJens Axboe umode_t i_mode; 1013c66ab6faSJens Axboe size_t len; 1014c66ab6faSJens Axboe int i, flags; 1015b92ce558SJens Axboe 1016b92ce558SJens Axboe /* 1017b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 1018b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 1019b92ce558SJens Axboe * piped splicing for that! 1020b92ce558SJens Axboe */ 10210f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 1022b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 1023b92ce558SJens Axboe return -EINVAL; 1024b92ce558SJens Axboe 1025b92ce558SJens Axboe /* 1026b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 1027b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 1028b92ce558SJens Axboe */ 1029b92ce558SJens Axboe pipe = current->splice_pipe; 103049570e9bSJens Axboe if (unlikely(!pipe)) { 1031b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 1032b92ce558SJens Axboe if (!pipe) 1033b92ce558SJens Axboe return -ENOMEM; 1034b92ce558SJens Axboe 1035b92ce558SJens Axboe /* 1036b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 103700522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 1038b92ce558SJens Axboe * PIPE_READERS appropriately. 1039b92ce558SJens Axboe */ 1040b92ce558SJens Axboe pipe->readers = 1; 1041b92ce558SJens Axboe 1042b92ce558SJens Axboe current->splice_pipe = pipe; 1043b92ce558SJens Axboe } 1044b92ce558SJens Axboe 1045b92ce558SJens Axboe /* 104673d62d83SIngo Molnar * Do the splice. 1047b92ce558SJens Axboe */ 1048b92ce558SJens Axboe ret = 0; 1049b92ce558SJens Axboe bytes = 0; 1050c66ab6faSJens Axboe len = sd->total_len; 1051c66ab6faSJens Axboe flags = sd->flags; 1052c66ab6faSJens Axboe 1053c66ab6faSJens Axboe /* 1054c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1055c66ab6faSJens Axboe */ 1056c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1057b92ce558SJens Axboe 1058b92ce558SJens Axboe while (len) { 105951a92c0fSJens Axboe size_t read_len; 1060bcd4f3acSJens Axboe loff_t pos = sd->pos; 1061b92ce558SJens Axboe 1062bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 106351a92c0fSJens Axboe if (unlikely(ret <= 0)) 1064b92ce558SJens Axboe goto out_release; 1065b92ce558SJens Axboe 1066b92ce558SJens Axboe read_len = ret; 1067c66ab6faSJens Axboe sd->total_len = read_len; 1068b92ce558SJens Axboe 1069b92ce558SJens Axboe /* 1070b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1071b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1072b92ce558SJens Axboe * could get stuck data in the internal pipe: 1073b92ce558SJens Axboe */ 1074c66ab6faSJens Axboe ret = actor(pipe, sd); 107551a92c0fSJens Axboe if (unlikely(ret <= 0)) 1076b92ce558SJens Axboe goto out_release; 1077b92ce558SJens Axboe 1078b92ce558SJens Axboe bytes += ret; 1079b92ce558SJens Axboe len -= ret; 1080bcd4f3acSJens Axboe sd->pos = pos; 1081b92ce558SJens Axboe 108251a92c0fSJens Axboe if (ret < read_len) 108351a92c0fSJens Axboe goto out_release; 1084b92ce558SJens Axboe } 1085b92ce558SJens Axboe 1086b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1087b92ce558SJens Axboe return bytes; 1088b92ce558SJens Axboe 1089b92ce558SJens Axboe out_release: 1090b92ce558SJens Axboe /* 1091b92ce558SJens Axboe * If we did an incomplete transfer we must release 1092b92ce558SJens Axboe * the pipe buffers in question: 1093b92ce558SJens Axboe */ 1094b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1095b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1096b92ce558SJens Axboe 1097b92ce558SJens Axboe if (buf->ops) { 1098b92ce558SJens Axboe buf->ops->release(pipe, buf); 1099b92ce558SJens Axboe buf->ops = NULL; 1100b92ce558SJens Axboe } 1101b92ce558SJens Axboe } 1102b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1103b92ce558SJens Axboe 1104b92ce558SJens Axboe /* 1105b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1106b92ce558SJens Axboe */ 1107b92ce558SJens Axboe if (bytes > 0) 1108b92ce558SJens Axboe return bytes; 1109b92ce558SJens Axboe 1110b92ce558SJens Axboe return ret; 1111c66ab6faSJens Axboe 1112c66ab6faSJens Axboe } 1113c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1114c66ab6faSJens Axboe 1115c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1116c66ab6faSJens Axboe struct splice_desc *sd) 1117c66ab6faSJens Axboe { 11186a14b90bSJens Axboe struct file *file = sd->u.file; 1119c66ab6faSJens Axboe 1120c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1121c66ab6faSJens Axboe } 1122c66ab6faSJens Axboe 1123932cc6d4SJens Axboe /** 1124932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1125932cc6d4SJens Axboe * @in: file to splice from 1126932cc6d4SJens Axboe * @ppos: input file offset 1127932cc6d4SJens Axboe * @out: file to splice to 1128932cc6d4SJens Axboe * @len: number of bytes to splice 1129932cc6d4SJens Axboe * @flags: splice modifier flags 1130932cc6d4SJens Axboe * 1131932cc6d4SJens Axboe * Description: 1132932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1133932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1134932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1135932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1136932cc6d4SJens Axboe * 1137932cc6d4SJens Axboe */ 1138c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1139c66ab6faSJens Axboe size_t len, unsigned int flags) 1140c66ab6faSJens Axboe { 1141c66ab6faSJens Axboe struct splice_desc sd = { 1142c66ab6faSJens Axboe .len = len, 1143c66ab6faSJens Axboe .total_len = len, 1144c66ab6faSJens Axboe .flags = flags, 1145c66ab6faSJens Axboe .pos = *ppos, 11466a14b90bSJens Axboe .u.file = out, 1147c66ab6faSJens Axboe }; 114851a92c0fSJens Axboe long ret; 1149c66ab6faSJens Axboe 1150c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 115151a92c0fSJens Axboe if (ret > 0) 115251a92c0fSJens Axboe *ppos += ret; 115351a92c0fSJens Axboe 1154c66ab6faSJens Axboe return ret; 1155b92ce558SJens Axboe } 1156b92ce558SJens Axboe 115783f9135bSJens Axboe /* 1158ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1159ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1160ddac0d39SJens Axboe * pipe. 1161ddac0d39SJens Axboe */ 1162ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1163ddac0d39SJens Axboe { 1164ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1165ddac0d39SJens Axboe return inode->i_pipe; 1166ddac0d39SJens Axboe 1167ddac0d39SJens Axboe return NULL; 1168ddac0d39SJens Axboe } 1169ddac0d39SJens Axboe 1170ddac0d39SJens Axboe /* 117183f9135bSJens Axboe * Determine where to splice to/from. 117283f9135bSJens Axboe */ 1173529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1174529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1175529565dcSIngo Molnar size_t len, unsigned int flags) 11765274f052SJens Axboe { 11773a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1178cbb7e577SJens Axboe loff_t offset, *off; 1179a4514ebdSJens Axboe long ret; 11805274f052SJens Axboe 11810f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1182529565dcSIngo Molnar if (pipe) { 1183529565dcSIngo Molnar if (off_in) 1184529565dcSIngo Molnar return -ESPIPE; 1185b92ce558SJens Axboe if (off_out) { 1186b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1187b92ce558SJens Axboe return -EINVAL; 1188cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1189b92ce558SJens Axboe return -EFAULT; 1190cbb7e577SJens Axboe off = &offset; 1191cbb7e577SJens Axboe } else 1192cbb7e577SJens Axboe off = &out->f_pos; 1193529565dcSIngo Molnar 1194a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1195a4514ebdSJens Axboe 1196a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1197a4514ebdSJens Axboe ret = -EFAULT; 1198a4514ebdSJens Axboe 1199a4514ebdSJens Axboe return ret; 1200529565dcSIngo Molnar } 12015274f052SJens Axboe 12020f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1203529565dcSIngo Molnar if (pipe) { 1204529565dcSIngo Molnar if (off_out) 1205529565dcSIngo Molnar return -ESPIPE; 1206b92ce558SJens Axboe if (off_in) { 1207b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1208b92ce558SJens Axboe return -EINVAL; 1209cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1210b92ce558SJens Axboe return -EFAULT; 1211cbb7e577SJens Axboe off = &offset; 1212cbb7e577SJens Axboe } else 1213cbb7e577SJens Axboe off = &in->f_pos; 1214529565dcSIngo Molnar 1215a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1216a4514ebdSJens Axboe 1217a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1218a4514ebdSJens Axboe ret = -EFAULT; 1219a4514ebdSJens Axboe 1220a4514ebdSJens Axboe return ret; 1221529565dcSIngo Molnar } 12225274f052SJens Axboe 12235274f052SJens Axboe return -EINVAL; 12245274f052SJens Axboe } 12255274f052SJens Axboe 1226912d35f8SJens Axboe /* 122775723957SLinus Torvalds * Do a copy-from-user while holding the mmap_semaphore for reading, in a 122875723957SLinus Torvalds * manner safe from deadlocking with simultaneous mmap() (grabbing mmap_sem 122975723957SLinus Torvalds * for writing) and page faulting on the user memory pointed to by src. 123075723957SLinus Torvalds * This assumes that we will very rarely hit the partial != 0 path, or this 123175723957SLinus Torvalds * will not be a win. 123275723957SLinus Torvalds */ 123375723957SLinus Torvalds static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n) 123475723957SLinus Torvalds { 123575723957SLinus Torvalds int partial; 123675723957SLinus Torvalds 123775723957SLinus Torvalds pagefault_disable(); 123875723957SLinus Torvalds partial = __copy_from_user_inatomic(dst, src, n); 123975723957SLinus Torvalds pagefault_enable(); 124075723957SLinus Torvalds 124175723957SLinus Torvalds /* 124275723957SLinus Torvalds * Didn't copy everything, drop the mmap_sem and do a faulting copy 124375723957SLinus Torvalds */ 124475723957SLinus Torvalds if (unlikely(partial)) { 124575723957SLinus Torvalds up_read(¤t->mm->mmap_sem); 124675723957SLinus Torvalds partial = copy_from_user(dst, src, n); 124775723957SLinus Torvalds down_read(¤t->mm->mmap_sem); 124875723957SLinus Torvalds } 124975723957SLinus Torvalds 125075723957SLinus Torvalds return partial; 125175723957SLinus Torvalds } 125275723957SLinus Torvalds 125375723957SLinus Torvalds /* 1254912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1255912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1256912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1257912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1258912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1259912d35f8SJens Axboe */ 1260912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1261912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 12627afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1263912d35f8SJens Axboe { 1264912d35f8SJens Axboe int buffers = 0, error = 0; 1265912d35f8SJens Axboe 1266912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1267912d35f8SJens Axboe 1268912d35f8SJens Axboe while (nr_vecs) { 1269912d35f8SJens Axboe unsigned long off, npages; 127075723957SLinus Torvalds struct iovec entry; 1271912d35f8SJens Axboe void __user *base; 1272912d35f8SJens Axboe size_t len; 1273912d35f8SJens Axboe int i; 1274912d35f8SJens Axboe 127575723957SLinus Torvalds error = -EFAULT; 127675723957SLinus Torvalds if (copy_from_user_mmap_sem(&entry, iov, sizeof(entry))) 1277912d35f8SJens Axboe break; 127875723957SLinus Torvalds 127975723957SLinus Torvalds base = entry.iov_base; 128075723957SLinus Torvalds len = entry.iov_len; 1281912d35f8SJens Axboe 1282912d35f8SJens Axboe /* 1283912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1284912d35f8SJens Axboe */ 128575723957SLinus Torvalds error = 0; 1286912d35f8SJens Axboe if (unlikely(!len)) 1287912d35f8SJens Axboe break; 1288912d35f8SJens Axboe error = -EFAULT; 1289912d35f8SJens Axboe if (unlikely(!base)) 1290912d35f8SJens Axboe break; 1291912d35f8SJens Axboe 1292912d35f8SJens Axboe /* 1293912d35f8SJens Axboe * Get this base offset and number of pages, then map 1294912d35f8SJens Axboe * in the user pages. 1295912d35f8SJens Axboe */ 1296912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12977afa6fd0SJens Axboe 12987afa6fd0SJens Axboe /* 12997afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 13007afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 13017afa6fd0SJens Axboe */ 13027afa6fd0SJens Axboe error = -EINVAL; 13037afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 13047afa6fd0SJens Axboe break; 13057afa6fd0SJens Axboe 1306912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1307912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1308912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1309912d35f8SJens Axboe 1310912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1311912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1312912d35f8SJens Axboe &pages[buffers], NULL); 1313912d35f8SJens Axboe 1314912d35f8SJens Axboe if (unlikely(error <= 0)) 1315912d35f8SJens Axboe break; 1316912d35f8SJens Axboe 1317912d35f8SJens Axboe /* 1318912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1319912d35f8SJens Axboe */ 1320912d35f8SJens Axboe for (i = 0; i < error; i++) { 13217591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1322912d35f8SJens Axboe 1323912d35f8SJens Axboe partial[buffers].offset = off; 1324912d35f8SJens Axboe partial[buffers].len = plen; 1325912d35f8SJens Axboe 1326912d35f8SJens Axboe off = 0; 1327912d35f8SJens Axboe len -= plen; 1328912d35f8SJens Axboe buffers++; 1329912d35f8SJens Axboe } 1330912d35f8SJens Axboe 1331912d35f8SJens Axboe /* 1332912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1333912d35f8SJens Axboe * means we have to move some of this into a pipe to 1334912d35f8SJens Axboe * be able to continue. 1335912d35f8SJens Axboe */ 1336912d35f8SJens Axboe if (len) 1337912d35f8SJens Axboe break; 1338912d35f8SJens Axboe 1339912d35f8SJens Axboe /* 1340912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1341912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1342912d35f8SJens Axboe * room for. 1343912d35f8SJens Axboe */ 1344912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1345912d35f8SJens Axboe break; 1346912d35f8SJens Axboe 1347912d35f8SJens Axboe nr_vecs--; 1348912d35f8SJens Axboe iov++; 1349912d35f8SJens Axboe } 1350912d35f8SJens Axboe 1351912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1352912d35f8SJens Axboe 1353912d35f8SJens Axboe if (buffers) 1354912d35f8SJens Axboe return buffers; 1355912d35f8SJens Axboe 1356912d35f8SJens Axboe return error; 1357912d35f8SJens Axboe } 1358912d35f8SJens Axboe 13596a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13606a14b90bSJens Axboe struct splice_desc *sd) 13616a14b90bSJens Axboe { 13626a14b90bSJens Axboe char *src; 13636a14b90bSJens Axboe int ret; 13646a14b90bSJens Axboe 1365cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 13666a14b90bSJens Axboe if (unlikely(ret)) 13676a14b90bSJens Axboe return ret; 13686a14b90bSJens Axboe 13696a14b90bSJens Axboe /* 13706a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13716a14b90bSJens Axboe * pages and doing an atomic copy 13726a14b90bSJens Axboe */ 13736a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13746a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13756a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13766a14b90bSJens Axboe sd->len); 13776a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13786a14b90bSJens Axboe if (!ret) { 13796a14b90bSJens Axboe ret = sd->len; 13806a14b90bSJens Axboe goto out; 13816a14b90bSJens Axboe } 13826a14b90bSJens Axboe } 13836a14b90bSJens Axboe 13846a14b90bSJens Axboe /* 13856a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13866a14b90bSJens Axboe */ 13876a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13886a14b90bSJens Axboe 13896a14b90bSJens Axboe ret = sd->len; 13906a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13916a14b90bSJens Axboe ret = -EFAULT; 13926a14b90bSJens Axboe 13936a14b90bSJens Axboe out: 13946a14b90bSJens Axboe if (ret > 0) 13956a14b90bSJens Axboe sd->u.userptr += ret; 13966a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13976a14b90bSJens Axboe return ret; 13986a14b90bSJens Axboe } 13996a14b90bSJens Axboe 14006a14b90bSJens Axboe /* 14016a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 14026a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 14036a14b90bSJens Axboe */ 14046a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 14056a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 14066a14b90bSJens Axboe { 14076a14b90bSJens Axboe struct pipe_inode_info *pipe; 14086a14b90bSJens Axboe struct splice_desc sd; 14096a14b90bSJens Axboe ssize_t size; 14106a14b90bSJens Axboe int error; 14116a14b90bSJens Axboe long ret; 14126a14b90bSJens Axboe 14136a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 14146a14b90bSJens Axboe if (!pipe) 14156a14b90bSJens Axboe return -EBADF; 14166a14b90bSJens Axboe 14176a14b90bSJens Axboe if (pipe->inode) 14186a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 14196a14b90bSJens Axboe 14206a14b90bSJens Axboe error = ret = 0; 14216a14b90bSJens Axboe while (nr_segs) { 14226a14b90bSJens Axboe void __user *base; 14236a14b90bSJens Axboe size_t len; 14246a14b90bSJens Axboe 14256a14b90bSJens Axboe /* 14266a14b90bSJens Axboe * Get user address base and length for this iovec. 14276a14b90bSJens Axboe */ 14286a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 14296a14b90bSJens Axboe if (unlikely(error)) 14306a14b90bSJens Axboe break; 14316a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 14326a14b90bSJens Axboe if (unlikely(error)) 14336a14b90bSJens Axboe break; 14346a14b90bSJens Axboe 14356a14b90bSJens Axboe /* 14366a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 14376a14b90bSJens Axboe */ 14386a14b90bSJens Axboe if (unlikely(!len)) 14396a14b90bSJens Axboe break; 14406a14b90bSJens Axboe if (unlikely(!base)) { 14416a14b90bSJens Axboe error = -EFAULT; 14426a14b90bSJens Axboe break; 14436a14b90bSJens Axboe } 14446a14b90bSJens Axboe 14456a14b90bSJens Axboe sd.len = 0; 14466a14b90bSJens Axboe sd.total_len = len; 14476a14b90bSJens Axboe sd.flags = flags; 14486a14b90bSJens Axboe sd.u.userptr = base; 14496a14b90bSJens Axboe sd.pos = 0; 14506a14b90bSJens Axboe 14516a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 14526a14b90bSJens Axboe if (size < 0) { 14536a14b90bSJens Axboe if (!ret) 14546a14b90bSJens Axboe ret = size; 14556a14b90bSJens Axboe 14566a14b90bSJens Axboe break; 14576a14b90bSJens Axboe } 14586a14b90bSJens Axboe 14596a14b90bSJens Axboe ret += size; 14606a14b90bSJens Axboe 14616a14b90bSJens Axboe if (size < len) 14626a14b90bSJens Axboe break; 14636a14b90bSJens Axboe 14646a14b90bSJens Axboe nr_segs--; 14656a14b90bSJens Axboe iov++; 14666a14b90bSJens Axboe } 14676a14b90bSJens Axboe 14686a14b90bSJens Axboe if (pipe->inode) 14696a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14706a14b90bSJens Axboe 14716a14b90bSJens Axboe if (!ret) 14726a14b90bSJens Axboe ret = error; 14736a14b90bSJens Axboe 14746a14b90bSJens Axboe return ret; 14756a14b90bSJens Axboe } 14766a14b90bSJens Axboe 1477912d35f8SJens Axboe /* 1478912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1479912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1480912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1481912d35f8SJens Axboe */ 14826a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1483912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1484912d35f8SJens Axboe { 1485ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1486912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1487912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1488912d35f8SJens Axboe struct splice_pipe_desc spd = { 1489912d35f8SJens Axboe .pages = pages, 1490912d35f8SJens Axboe .partial = partial, 1491912d35f8SJens Axboe .flags = flags, 1492912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1493912d35f8SJens Axboe }; 1494912d35f8SJens Axboe 14950f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1496ddac0d39SJens Axboe if (!pipe) 1497912d35f8SJens Axboe return -EBADF; 1498912d35f8SJens Axboe 14997afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 15007afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1501912d35f8SJens Axboe if (spd.nr_pages <= 0) 1502912d35f8SJens Axboe return spd.nr_pages; 1503912d35f8SJens Axboe 150400522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1505912d35f8SJens Axboe } 1506912d35f8SJens Axboe 15076a14b90bSJens Axboe /* 15086a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 15096a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 15106a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 15116a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 15126a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 15136a14b90bSJens Axboe * solutions for that: 15146a14b90bSJens Axboe * 15156a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 15166a14b90bSJens Axboe * do a regular read() on the buffer anyway. 15176a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 15186a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 15196a14b90bSJens Axboe * 15206a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 15216a14b90bSJens Axboe * 15226a14b90bSJens Axboe */ 1523912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1524912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1525912d35f8SJens Axboe { 1526912d35f8SJens Axboe struct file *file; 1527912d35f8SJens Axboe long error; 1528912d35f8SJens Axboe int fput; 1529912d35f8SJens Axboe 15306a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 15316a14b90bSJens Axboe return -EINVAL; 15326a14b90bSJens Axboe else if (unlikely(!nr_segs)) 15336a14b90bSJens Axboe return 0; 15346a14b90bSJens Axboe 1535912d35f8SJens Axboe error = -EBADF; 1536912d35f8SJens Axboe file = fget_light(fd, &fput); 1537912d35f8SJens Axboe if (file) { 1538912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 15396a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 15406a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 15416a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1542912d35f8SJens Axboe 1543912d35f8SJens Axboe fput_light(file, fput); 1544912d35f8SJens Axboe } 1545912d35f8SJens Axboe 1546912d35f8SJens Axboe return error; 1547912d35f8SJens Axboe } 1548912d35f8SJens Axboe 1549529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1550529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1551529565dcSIngo Molnar size_t len, unsigned int flags) 15525274f052SJens Axboe { 15535274f052SJens Axboe long error; 15545274f052SJens Axboe struct file *in, *out; 15555274f052SJens Axboe int fput_in, fput_out; 15565274f052SJens Axboe 15575274f052SJens Axboe if (unlikely(!len)) 15585274f052SJens Axboe return 0; 15595274f052SJens Axboe 15605274f052SJens Axboe error = -EBADF; 1561529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 15625274f052SJens Axboe if (in) { 15635274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1564529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15655274f052SJens Axboe if (out) { 15665274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1567529565dcSIngo Molnar error = do_splice(in, off_in, 1568529565dcSIngo Molnar out, off_out, 1569529565dcSIngo Molnar len, flags); 15705274f052SJens Axboe fput_light(out, fput_out); 15715274f052SJens Axboe } 15725274f052SJens Axboe } 15735274f052SJens Axboe 15745274f052SJens Axboe fput_light(in, fput_in); 15755274f052SJens Axboe } 15765274f052SJens Axboe 15775274f052SJens Axboe return error; 15785274f052SJens Axboe } 157970524490SJens Axboe 158070524490SJens Axboe /* 1581aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1582aadd06e5SJens Axboe * return an appropriate error. 1583aadd06e5SJens Axboe */ 1584aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1585aadd06e5SJens Axboe { 1586aadd06e5SJens Axboe int ret; 1587aadd06e5SJens Axboe 1588aadd06e5SJens Axboe /* 1589aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1590aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1591aadd06e5SJens Axboe */ 1592aadd06e5SJens Axboe if (pipe->nrbufs) 1593aadd06e5SJens Axboe return 0; 1594aadd06e5SJens Axboe 1595aadd06e5SJens Axboe ret = 0; 1596aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1597aadd06e5SJens Axboe 1598aadd06e5SJens Axboe while (!pipe->nrbufs) { 1599aadd06e5SJens Axboe if (signal_pending(current)) { 1600aadd06e5SJens Axboe ret = -ERESTARTSYS; 1601aadd06e5SJens Axboe break; 1602aadd06e5SJens Axboe } 1603aadd06e5SJens Axboe if (!pipe->writers) 1604aadd06e5SJens Axboe break; 1605aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1606aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1607aadd06e5SJens Axboe ret = -EAGAIN; 1608aadd06e5SJens Axboe break; 1609aadd06e5SJens Axboe } 1610aadd06e5SJens Axboe } 1611aadd06e5SJens Axboe pipe_wait(pipe); 1612aadd06e5SJens Axboe } 1613aadd06e5SJens Axboe 1614aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1615aadd06e5SJens Axboe return ret; 1616aadd06e5SJens Axboe } 1617aadd06e5SJens Axboe 1618aadd06e5SJens Axboe /* 1619aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1620aadd06e5SJens Axboe * return an appropriate error. 1621aadd06e5SJens Axboe */ 1622aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1623aadd06e5SJens Axboe { 1624aadd06e5SJens Axboe int ret; 1625aadd06e5SJens Axboe 1626aadd06e5SJens Axboe /* 1627aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1628aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1629aadd06e5SJens Axboe */ 1630aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1631aadd06e5SJens Axboe return 0; 1632aadd06e5SJens Axboe 1633aadd06e5SJens Axboe ret = 0; 1634aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1635aadd06e5SJens Axboe 1636aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1637aadd06e5SJens Axboe if (!pipe->readers) { 1638aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1639aadd06e5SJens Axboe ret = -EPIPE; 1640aadd06e5SJens Axboe break; 1641aadd06e5SJens Axboe } 1642aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1643aadd06e5SJens Axboe ret = -EAGAIN; 1644aadd06e5SJens Axboe break; 1645aadd06e5SJens Axboe } 1646aadd06e5SJens Axboe if (signal_pending(current)) { 1647aadd06e5SJens Axboe ret = -ERESTARTSYS; 1648aadd06e5SJens Axboe break; 1649aadd06e5SJens Axboe } 1650aadd06e5SJens Axboe pipe->waiting_writers++; 1651aadd06e5SJens Axboe pipe_wait(pipe); 1652aadd06e5SJens Axboe pipe->waiting_writers--; 1653aadd06e5SJens Axboe } 1654aadd06e5SJens Axboe 1655aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1656aadd06e5SJens Axboe return ret; 1657aadd06e5SJens Axboe } 1658aadd06e5SJens Axboe 1659aadd06e5SJens Axboe /* 166070524490SJens Axboe * Link contents of ipipe to opipe. 166170524490SJens Axboe */ 166270524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 166370524490SJens Axboe struct pipe_inode_info *opipe, 166470524490SJens Axboe size_t len, unsigned int flags) 166570524490SJens Axboe { 166670524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1667aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 166870524490SJens Axboe 166970524490SJens Axboe /* 167070524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 167170524490SJens Axboe * grabbing by inode address. Otherwise two different processes 167270524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 167370524490SJens Axboe */ 167462752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 167570524490SJens Axboe 1676aadd06e5SJens Axboe do { 167770524490SJens Axboe if (!opipe->readers) { 167870524490SJens Axboe send_sig(SIGPIPE, current, 0); 167970524490SJens Axboe if (!ret) 168070524490SJens Axboe ret = -EPIPE; 168170524490SJens Axboe break; 168270524490SJens Axboe } 168370524490SJens Axboe 168470524490SJens Axboe /* 1685aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1686aadd06e5SJens Axboe * output room, break. 168770524490SJens Axboe */ 1688aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1689aadd06e5SJens Axboe break; 1690aadd06e5SJens Axboe 1691aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1692aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 169370524490SJens Axboe 169470524490SJens Axboe /* 169570524490SJens Axboe * Get a reference to this pipe buffer, 169670524490SJens Axboe * so we can copy the contents over. 169770524490SJens Axboe */ 169870524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 169970524490SJens Axboe 170070524490SJens Axboe obuf = opipe->bufs + nbuf; 170170524490SJens Axboe *obuf = *ibuf; 170270524490SJens Axboe 17037afa6fd0SJens Axboe /* 17047afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 17057afa6fd0SJens Axboe * prevent multiple steals of this page. 17067afa6fd0SJens Axboe */ 17077afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 17087afa6fd0SJens Axboe 170970524490SJens Axboe if (obuf->len > len) 171070524490SJens Axboe obuf->len = len; 171170524490SJens Axboe 171270524490SJens Axboe opipe->nrbufs++; 171370524490SJens Axboe ret += obuf->len; 171470524490SJens Axboe len -= obuf->len; 1715aadd06e5SJens Axboe i++; 1716aadd06e5SJens Axboe } while (len); 171770524490SJens Axboe 171862752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 171970524490SJens Axboe 1720aadd06e5SJens Axboe /* 1721aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1722aadd06e5SJens Axboe */ 1723aadd06e5SJens Axboe if (ret > 0) { 172470524490SJens Axboe smp_mb(); 172570524490SJens Axboe if (waitqueue_active(&opipe->wait)) 172670524490SJens Axboe wake_up_interruptible(&opipe->wait); 172770524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 172870524490SJens Axboe } 172970524490SJens Axboe 173070524490SJens Axboe return ret; 173170524490SJens Axboe } 173270524490SJens Axboe 173370524490SJens Axboe /* 173470524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 173570524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 173670524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 173770524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 173870524490SJens Axboe */ 173970524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 174070524490SJens Axboe unsigned int flags) 174170524490SJens Axboe { 17420f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 17430f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1744aadd06e5SJens Axboe int ret = -EINVAL; 174570524490SJens Axboe 174670524490SJens Axboe /* 1747aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1748aadd06e5SJens Axboe * copying the data. 174970524490SJens Axboe */ 1750aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1751aadd06e5SJens Axboe /* 1752aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1753aadd06e5SJens Axboe * ordering doesn't really matter. 1754aadd06e5SJens Axboe */ 1755aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1756aadd06e5SJens Axboe if (!ret) { 1757aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 1758aadd06e5SJens Axboe if (!ret) { 1759aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1760aadd06e5SJens Axboe if (!ret && (flags & SPLICE_F_NONBLOCK)) 1761aadd06e5SJens Axboe ret = -EAGAIN; 1762aadd06e5SJens Axboe } 1763aadd06e5SJens Axboe } 1764aadd06e5SJens Axboe } 176570524490SJens Axboe 1766aadd06e5SJens Axboe return ret; 176770524490SJens Axboe } 176870524490SJens Axboe 176970524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 177070524490SJens Axboe { 177170524490SJens Axboe struct file *in; 177270524490SJens Axboe int error, fput_in; 177370524490SJens Axboe 177470524490SJens Axboe if (unlikely(!len)) 177570524490SJens Axboe return 0; 177670524490SJens Axboe 177770524490SJens Axboe error = -EBADF; 177870524490SJens Axboe in = fget_light(fdin, &fput_in); 177970524490SJens Axboe if (in) { 178070524490SJens Axboe if (in->f_mode & FMODE_READ) { 178170524490SJens Axboe int fput_out; 178270524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 178370524490SJens Axboe 178470524490SJens Axboe if (out) { 178570524490SJens Axboe if (out->f_mode & FMODE_WRITE) 178670524490SJens Axboe error = do_tee(in, out, len, flags); 178770524490SJens Axboe fput_light(out, fput_out); 178870524490SJens Axboe } 178970524490SJens Axboe } 179070524490SJens Axboe fput_light(in, fput_in); 179170524490SJens Axboe } 179270524490SJens Axboe 179370524490SJens Axboe return error; 179470524490SJens Axboe } 1795