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: 167932cc6d4SJens Axboe * @spd contains a map of pages and len/offset tupples, a long 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; 268912d35f8SJens Axboe unsigned int loff, nr_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; 284912d35f8SJens Axboe nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2855274f052SJens Axboe 2865274f052SJens Axboe if (nr_pages > PIPE_BUFFERS) 2875274f052SJens Axboe nr_pages = PIPE_BUFFERS; 2885274f052SJens Axboe 2895274f052SJens Axboe /* 29086aa5ac5SJens Axboe * Don't try to 2nd guess the read-ahead logic, call into 29186aa5ac5SJens Axboe * page_cache_readahead() like the page cache reads would do. 2925274f052SJens Axboe */ 293eb645a24SJens Axboe page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); 2945274f052SJens Axboe 2955274f052SJens Axboe /* 296eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29782aa5d61SJens Axboe */ 298eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 299eb20796bSJens Axboe 3005274f052SJens Axboe /* 301eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 302932cc6d4SJens Axboe * allocate the rest and fill in the holes. 303eb20796bSJens Axboe */ 304932cc6d4SJens Axboe error = 0; 305eb20796bSJens Axboe index += spd.nr_pages; 306eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 307eb20796bSJens Axboe /* 308eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 309eb20796bSJens Axboe * the first hole. 3105274f052SJens Axboe */ 3117480a904SJens Axboe page = find_get_page(mapping, index); 3127480a904SJens Axboe if (!page) { 3137480a904SJens Axboe /* 314e27dedd8SJens Axboe * Make sure the read-ahead engine is notified 315e27dedd8SJens Axboe * about this failure. 316e27dedd8SJens Axboe */ 317e27dedd8SJens Axboe handle_ra_miss(mapping, &in->f_ra, index); 318e27dedd8SJens Axboe 319e27dedd8SJens Axboe /* 320eb20796bSJens Axboe * page didn't exist, allocate one. 3217480a904SJens Axboe */ 3227480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3235274f052SJens Axboe if (!page) 3245274f052SJens Axboe break; 3255274f052SJens Axboe 3267480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3272ae88149SNick Piggin GFP_KERNEL); 3285274f052SJens Axboe if (unlikely(error)) { 3295274f052SJens Axboe page_cache_release(page); 330a0548871SJens Axboe if (error == -EEXIST) 331a0548871SJens Axboe continue; 3325274f052SJens Axboe break; 3335274f052SJens Axboe } 334eb20796bSJens Axboe /* 335eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 336eb20796bSJens Axboe * to avoid convoluting the logic below even more. 337eb20796bSJens Axboe */ 338eb20796bSJens Axboe unlock_page(page); 3395274f052SJens Axboe } 3407480a904SJens Axboe 341eb20796bSJens Axboe pages[spd.nr_pages++] = page; 342eb20796bSJens Axboe index++; 343eb20796bSJens Axboe } 344eb20796bSJens Axboe 345eb20796bSJens Axboe /* 346eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 347eb20796bSJens Axboe * pages, fill in the partial map, etc. 348eb20796bSJens Axboe */ 349eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 350eb20796bSJens Axboe nr_pages = spd.nr_pages; 351eb20796bSJens Axboe spd.nr_pages = 0; 352eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 353eb20796bSJens Axboe unsigned int this_len; 354eb20796bSJens Axboe 355eb20796bSJens Axboe if (!len) 356eb20796bSJens Axboe break; 357eb20796bSJens Axboe 358eb20796bSJens Axboe /* 359eb20796bSJens Axboe * this_len is the max we'll use from this page 360eb20796bSJens Axboe */ 361eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 362eb20796bSJens Axboe page = pages[page_nr]; 363eb20796bSJens Axboe 3647480a904SJens Axboe /* 3657480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3667480a904SJens Axboe */ 3677480a904SJens Axboe if (!PageUptodate(page)) { 368c4f895cbSJens Axboe /* 369c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 370c4f895cbSJens Axboe * for an in-flight io page 371c4f895cbSJens Axboe */ 3729ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3739ae9d68cSFengguang Wu if (TestSetPageLocked(page)) 374c4f895cbSJens Axboe break; 3759ae9d68cSFengguang Wu } else 3767480a904SJens Axboe lock_page(page); 3777480a904SJens Axboe 3787480a904SJens Axboe /* 3797480a904SJens Axboe * page was truncated, stop here. if this isn't the 3807480a904SJens Axboe * first page, we'll just complete what we already 3817480a904SJens Axboe * added 3827480a904SJens Axboe */ 3837480a904SJens Axboe if (!page->mapping) { 3847480a904SJens Axboe unlock_page(page); 3857480a904SJens Axboe break; 3867480a904SJens Axboe } 3877480a904SJens Axboe /* 3887480a904SJens Axboe * page was already under io and is now done, great 3897480a904SJens Axboe */ 3907480a904SJens Axboe if (PageUptodate(page)) { 3917480a904SJens Axboe unlock_page(page); 3927480a904SJens Axboe goto fill_it; 3937480a904SJens Axboe } 3947480a904SJens Axboe 3957480a904SJens Axboe /* 3967480a904SJens Axboe * need to read in the page 3977480a904SJens Axboe */ 3987480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 3997480a904SJens Axboe if (unlikely(error)) { 400eb20796bSJens Axboe /* 401eb20796bSJens Axboe * We really should re-lookup the page here, 402eb20796bSJens Axboe * but it complicates things a lot. Instead 403eb20796bSJens Axboe * lets just do what we already stored, and 404eb20796bSJens Axboe * we'll get it the next time we are called. 405eb20796bSJens Axboe */ 4067480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 407eb20796bSJens Axboe error = 0; 408eb20796bSJens Axboe 4097480a904SJens Axboe break; 4107480a904SJens Axboe } 411620a324bSJens Axboe } 412620a324bSJens Axboe fill_it: 41391ad66efSJens Axboe /* 414620a324bSJens Axboe * i_size must be checked after PageUptodate. 41591ad66efSJens Axboe */ 41691ad66efSJens Axboe isize = i_size_read(mapping->host); 41791ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 418eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 41991ad66efSJens Axboe break; 42091ad66efSJens Axboe 42191ad66efSJens Axboe /* 42291ad66efSJens Axboe * if this is the last page, see if we need to shrink 42391ad66efSJens Axboe * the length and stop 42491ad66efSJens Axboe */ 42591ad66efSJens Axboe if (end_index == index) { 426475ecadeSHugh Dickins unsigned int plen; 427475ecadeSHugh Dickins 428475ecadeSHugh Dickins /* 429475ecadeSHugh Dickins * max good bytes in this page 430475ecadeSHugh Dickins */ 431475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 432475ecadeSHugh Dickins if (plen <= loff) 43391ad66efSJens Axboe break; 434475ecadeSHugh Dickins 43591ad66efSJens Axboe /* 43691ad66efSJens Axboe * force quit after adding this page 43791ad66efSJens Axboe */ 438475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 439eb20796bSJens Axboe len = this_len; 44091ad66efSJens Axboe } 441620a324bSJens Axboe 442eb20796bSJens Axboe partial[page_nr].offset = loff; 443eb20796bSJens Axboe partial[page_nr].len = this_len; 44482aa5d61SJens Axboe len -= this_len; 44591ad66efSJens Axboe loff = 0; 446eb20796bSJens Axboe spd.nr_pages++; 447eb20796bSJens Axboe index++; 4485274f052SJens Axboe } 4495274f052SJens Axboe 450eb20796bSJens Axboe /* 451475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 452eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 453eb20796bSJens Axboe */ 454eb20796bSJens Axboe while (page_nr < nr_pages) 455eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 456eb20796bSJens Axboe 457912d35f8SJens Axboe if (spd.nr_pages) 45800522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 45916c523ddSJens Axboe 4607480a904SJens Axboe return error; 4615274f052SJens Axboe } 4625274f052SJens Axboe 46383f9135bSJens Axboe /** 46483f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46583f9135bSJens Axboe * @in: file to splice from 466932cc6d4SJens Axboe * @ppos: position in @in 46783f9135bSJens Axboe * @pipe: pipe to splice to 46883f9135bSJens Axboe * @len: number of bytes to splice 46983f9135bSJens Axboe * @flags: splice modifier flags 47083f9135bSJens Axboe * 471932cc6d4SJens Axboe * Description: 472932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 473932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 474932cc6d4SJens Axboe * a readpage() hook. 475932cc6d4SJens Axboe * 47683f9135bSJens Axboe */ 477cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 478cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 479cbb7e577SJens Axboe unsigned int flags) 4805274f052SJens Axboe { 4815274f052SJens Axboe ssize_t spliced; 4825274f052SJens Axboe int ret; 483d366d398SJens Axboe loff_t isize, left; 484d366d398SJens Axboe 485d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 486d366d398SJens Axboe if (unlikely(*ppos >= isize)) 487d366d398SJens Axboe return 0; 488d366d398SJens Axboe 489d366d398SJens Axboe left = isize - *ppos; 490d366d398SJens Axboe if (unlikely(left < len)) 491d366d398SJens Axboe len = left; 4925274f052SJens Axboe 4935274f052SJens Axboe ret = 0; 4945274f052SJens Axboe spliced = 0; 49551a92c0fSJens Axboe while (len && !spliced) { 496cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4975274f052SJens Axboe 498c4f895cbSJens Axboe if (ret < 0) 4995274f052SJens Axboe break; 500c4f895cbSJens Axboe else if (!ret) { 501c4f895cbSJens Axboe if (spliced) 502c4f895cbSJens Axboe break; 503c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 504c4f895cbSJens Axboe ret = -EAGAIN; 505c4f895cbSJens Axboe break; 506c4f895cbSJens Axboe } 507c4f895cbSJens Axboe } 5085274f052SJens Axboe 509cbb7e577SJens Axboe *ppos += ret; 5105274f052SJens Axboe len -= ret; 5115274f052SJens Axboe spliced += ret; 5125274f052SJens Axboe } 5135274f052SJens Axboe 5145274f052SJens Axboe if (spliced) 5155274f052SJens Axboe return spliced; 5165274f052SJens Axboe 5175274f052SJens Axboe return ret; 5185274f052SJens Axboe } 5195274f052SJens Axboe 520059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 521059a8f37SJens Axboe 5225274f052SJens Axboe /* 5234f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 524016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5255274f052SJens Axboe */ 52676ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5275274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5285274f052SJens Axboe { 5296a14b90bSJens Axboe struct file *file = sd->u.file; 5305274f052SJens Axboe loff_t pos = sd->pos; 531f84d7519SJens Axboe int ret, more; 5325274f052SJens Axboe 533cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 534f84d7519SJens Axboe if (!ret) { 535b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5365274f052SJens Axboe 537f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 538f84d7519SJens Axboe sd->len, &pos, more); 539f84d7519SJens Axboe } 5405274f052SJens Axboe 541016b661eSJens Axboe return ret; 5425274f052SJens Axboe } 5435274f052SJens Axboe 5445274f052SJens Axboe /* 5455274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5465274f052SJens Axboe * basically three cases: 5475274f052SJens Axboe * 5485274f052SJens Axboe * - Destination page already exists in the address space and there 5495274f052SJens Axboe * are users of it. For that case we have no other option that 5505274f052SJens Axboe * copying the data. Tough luck. 5515274f052SJens Axboe * - Destination page already exists in the address space, but there 5525274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5535274f052SJens Axboe * through to last case. 5545274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5555274f052SJens Axboe * the page cache and avoid the copy. 5565274f052SJens Axboe * 55783f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55883f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 55983f9135bSJens Axboe * file address space page cache. This is possible if no one else has 56083f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 56183f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 56283f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5635274f052SJens Axboe */ 56476ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5655274f052SJens Axboe struct splice_desc *sd) 5665274f052SJens Axboe { 5676a14b90bSJens Axboe struct file *file = sd->u.file; 5685274f052SJens Axboe struct address_space *mapping = file->f_mapping; 569016b661eSJens Axboe unsigned int offset, this_len; 5705274f052SJens Axboe struct page *page; 5715274f052SJens Axboe pgoff_t index; 5723e7ee3e7SJens Axboe int ret; 5735274f052SJens Axboe 5745274f052SJens Axboe /* 57549d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5765274f052SJens Axboe */ 577cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 578f84d7519SJens Axboe if (unlikely(ret)) 579f84d7519SJens Axboe return ret; 5805274f052SJens Axboe 5815274f052SJens Axboe index = sd->pos >> PAGE_CACHE_SHIFT; 5825274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5835274f052SJens Axboe 584016b661eSJens Axboe this_len = sd->len; 585016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 586016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 587016b661eSJens Axboe 5885274f052SJens Axboe find_page: 5899e0267c2SJens Axboe page = find_lock_page(mapping, index); 5909e0267c2SJens Axboe if (!page) { 5915274f052SJens Axboe ret = -ENOMEM; 5929e0267c2SJens Axboe page = page_cache_alloc_cold(mapping); 5939e0267c2SJens Axboe if (unlikely(!page)) 594e6e80f29SJens Axboe goto out_ret; 5955274f052SJens Axboe 5965274f052SJens Axboe /* 5979e0267c2SJens Axboe * This will also lock the page 5989e0267c2SJens Axboe */ 5999e0267c2SJens Axboe ret = add_to_page_cache_lru(page, mapping, index, 6002ae88149SNick Piggin GFP_KERNEL); 6019e0267c2SJens Axboe if (unlikely(ret)) 6029e0267c2SJens Axboe goto out; 6039e0267c2SJens Axboe } 6049e0267c2SJens Axboe 605016b661eSJens Axboe ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); 606bfc4ee39SJens Axboe if (unlikely(ret)) { 607bfc4ee39SJens Axboe loff_t isize = i_size_read(mapping->host); 608bfc4ee39SJens Axboe 609bfc4ee39SJens Axboe if (ret != AOP_TRUNCATED_PAGE) 610bfc4ee39SJens Axboe unlock_page(page); 6114f6f0bd2SJens Axboe page_cache_release(page); 612bfc4ee39SJens Axboe if (ret == AOP_TRUNCATED_PAGE) 6134f6f0bd2SJens Axboe goto find_page; 614bfc4ee39SJens Axboe 615bfc4ee39SJens Axboe /* 616bfc4ee39SJens Axboe * prepare_write() may have instantiated a few blocks 617bfc4ee39SJens Axboe * outside i_size. Trim these off again. 618bfc4ee39SJens Axboe */ 619bfc4ee39SJens Axboe if (sd->pos + this_len > isize) 620bfc4ee39SJens Axboe vmtruncate(mapping->host, isize); 621bfc4ee39SJens Axboe 622e6e80f29SJens Axboe goto out_ret; 623bfc4ee39SJens Axboe } 6245274f052SJens Axboe 6250568b409SJens Axboe if (buf->page != page) { 626f84d7519SJens Axboe /* 627f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 628f84d7519SJens Axboe */ 62976ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 630f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 6315abc97aaSJens Axboe 632016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6335274f052SJens Axboe flush_dcache_page(page); 634f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 63576ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6365abc97aaSJens Axboe } 6375274f052SJens Axboe 638016b661eSJens Axboe ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); 639d9993c37SDmitriy Monakhov if (ret) { 640d9993c37SDmitriy Monakhov if (ret == AOP_TRUNCATED_PAGE) { 641d9993c37SDmitriy Monakhov page_cache_release(page); 642d9993c37SDmitriy Monakhov goto find_page; 643d9993c37SDmitriy Monakhov } 644d9993c37SDmitriy Monakhov if (ret < 0) 645d9993c37SDmitriy Monakhov goto out; 646d9993c37SDmitriy Monakhov /* 647d9993c37SDmitriy Monakhov * Partial write has happened, so 'ret' already initialized by 648d9993c37SDmitriy Monakhov * number of bytes written, Where is nothing we have to do here. 649d9993c37SDmitriy Monakhov */ 650d9993c37SDmitriy Monakhov } else 651d9993c37SDmitriy Monakhov ret = this_len; 652016b661eSJens Axboe /* 6530568b409SJens Axboe * Return the number of bytes written and mark page as 6540568b409SJens Axboe * accessed, we are now done! 655016b661eSJens Axboe */ 656c7f21e4fSJens Axboe mark_page_accessed(page); 6570568b409SJens Axboe out: 6580568b409SJens Axboe page_cache_release(page); 6594f6f0bd2SJens Axboe unlock_page(page); 660e6e80f29SJens Axboe out_ret: 6615274f052SJens Axboe return ret; 6625274f052SJens Axboe } 6635274f052SJens Axboe 664932cc6d4SJens Axboe /** 665932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 666932cc6d4SJens Axboe * @pipe: pipe to splice from 667932cc6d4SJens Axboe * @sd: information to @actor 668932cc6d4SJens Axboe * @actor: handler that splices the data 669932cc6d4SJens Axboe * 670932cc6d4SJens Axboe * Description: 671932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 672932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 673932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 674932cc6d4SJens Axboe * pipe_to_user. 675932cc6d4SJens Axboe * 67683f9135bSJens Axboe */ 677c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 678c66ab6faSJens Axboe splice_actor *actor) 6795274f052SJens Axboe { 6805274f052SJens Axboe int ret, do_wakeup, err; 6815274f052SJens Axboe 6825274f052SJens Axboe ret = 0; 6835274f052SJens Axboe do_wakeup = 0; 6845274f052SJens Axboe 6855274f052SJens Axboe for (;;) { 6866f767b04SJens Axboe if (pipe->nrbufs) { 6876f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 688d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6895274f052SJens Axboe 690c66ab6faSJens Axboe sd->len = buf->len; 691c66ab6faSJens Axboe if (sd->len > sd->total_len) 692c66ab6faSJens Axboe sd->len = sd->total_len; 6935274f052SJens Axboe 694c66ab6faSJens Axboe err = actor(pipe, buf, sd); 695016b661eSJens Axboe if (err <= 0) { 6965274f052SJens Axboe if (!ret && err != -ENODATA) 6975274f052SJens Axboe ret = err; 6985274f052SJens Axboe 6995274f052SJens Axboe break; 7005274f052SJens Axboe } 7015274f052SJens Axboe 702016b661eSJens Axboe ret += err; 703016b661eSJens Axboe buf->offset += err; 704016b661eSJens Axboe buf->len -= err; 705016b661eSJens Axboe 706c66ab6faSJens Axboe sd->len -= err; 707c66ab6faSJens Axboe sd->pos += err; 708c66ab6faSJens Axboe sd->total_len -= err; 709c66ab6faSJens Axboe if (sd->len) 710016b661eSJens Axboe continue; 71173d62d83SIngo Molnar 7125274f052SJens Axboe if (!buf->len) { 7135274f052SJens Axboe buf->ops = NULL; 7143a326a2cSIngo Molnar ops->release(pipe, buf); 7156f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 7166f767b04SJens Axboe pipe->nrbufs--; 7176f767b04SJens Axboe if (pipe->inode) 7185274f052SJens Axboe do_wakeup = 1; 7195274f052SJens Axboe } 7205274f052SJens Axboe 721c66ab6faSJens Axboe if (!sd->total_len) 7225274f052SJens Axboe break; 7235274f052SJens Axboe } 7245274f052SJens Axboe 7256f767b04SJens Axboe if (pipe->nrbufs) 7265274f052SJens Axboe continue; 7273a326a2cSIngo Molnar if (!pipe->writers) 7285274f052SJens Axboe break; 7293a326a2cSIngo Molnar if (!pipe->waiting_writers) { 7305274f052SJens Axboe if (ret) 7315274f052SJens Axboe break; 7325274f052SJens Axboe } 7335274f052SJens Axboe 734c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 73529e35094SLinus Torvalds if (!ret) 73629e35094SLinus Torvalds ret = -EAGAIN; 73729e35094SLinus Torvalds break; 73829e35094SLinus Torvalds } 73929e35094SLinus Torvalds 7405274f052SJens Axboe if (signal_pending(current)) { 7415274f052SJens Axboe if (!ret) 7425274f052SJens Axboe ret = -ERESTARTSYS; 7435274f052SJens Axboe break; 7445274f052SJens Axboe } 7455274f052SJens Axboe 7465274f052SJens Axboe if (do_wakeup) { 747c0bd1f65SJens Axboe smp_mb(); 7483a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7493a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 7503a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7515274f052SJens Axboe do_wakeup = 0; 7525274f052SJens Axboe } 7535274f052SJens Axboe 7543a326a2cSIngo Molnar pipe_wait(pipe); 7555274f052SJens Axboe } 7565274f052SJens Axboe 7575274f052SJens Axboe if (do_wakeup) { 758c0bd1f65SJens Axboe smp_mb(); 7593a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7603a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7613a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7625274f052SJens Axboe } 7635274f052SJens Axboe 7645274f052SJens Axboe return ret; 7655274f052SJens Axboe } 76640bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7675274f052SJens Axboe 768932cc6d4SJens Axboe /** 769932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 770932cc6d4SJens Axboe * @pipe: pipe to splice from 771932cc6d4SJens Axboe * @out: file to splice to 772932cc6d4SJens Axboe * @ppos: position in @out 773932cc6d4SJens Axboe * @len: how many bytes to splice 774932cc6d4SJens Axboe * @flags: splice modifier flags 775932cc6d4SJens Axboe * @actor: handler that splices the data 776932cc6d4SJens Axboe * 777932cc6d4SJens Axboe * Description: 778932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 779932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 780932cc6d4SJens Axboe * 781932cc6d4SJens Axboe */ 7826da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7836da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7846da61809SMark Fasheh splice_actor *actor) 7856da61809SMark Fasheh { 7866da61809SMark Fasheh ssize_t ret; 7876da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 788c66ab6faSJens Axboe struct splice_desc sd = { 789c66ab6faSJens Axboe .total_len = len, 790c66ab6faSJens Axboe .flags = flags, 791c66ab6faSJens Axboe .pos = *ppos, 7926a14b90bSJens Axboe .u.file = out, 793c66ab6faSJens Axboe }; 7946da61809SMark Fasheh 7956da61809SMark Fasheh /* 7966da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7976da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7986da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7996da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 8006da61809SMark Fasheh */ 8016da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 802c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 8036da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 8046da61809SMark Fasheh 8056da61809SMark Fasheh return ret; 8066da61809SMark Fasheh } 8076da61809SMark Fasheh 8086da61809SMark Fasheh /** 8096da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 8106da61809SMark Fasheh * @pipe: pipe info 8116da61809SMark Fasheh * @out: file to write to 812932cc6d4SJens Axboe * @ppos: position in @out 8136da61809SMark Fasheh * @len: number of bytes to splice 8146da61809SMark Fasheh * @flags: splice modifier flags 8156da61809SMark Fasheh * 816932cc6d4SJens Axboe * Description: 8176da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 8186da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 8196da61809SMark Fasheh * for acquiring i_mutex on both inodes. 8206da61809SMark Fasheh * 8216da61809SMark Fasheh */ 8226da61809SMark Fasheh ssize_t 8236da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 8246da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 8256da61809SMark Fasheh { 8266da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 8276da61809SMark Fasheh struct inode *inode = mapping->host; 828c66ab6faSJens Axboe struct splice_desc sd = { 829c66ab6faSJens Axboe .total_len = len, 830c66ab6faSJens Axboe .flags = flags, 831c66ab6faSJens Axboe .pos = *ppos, 8326a14b90bSJens Axboe .u.file = out, 833c66ab6faSJens Axboe }; 8346da61809SMark Fasheh ssize_t ret; 8356da61809SMark Fasheh int err; 8366da61809SMark Fasheh 8370f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 8388c34e2d6SJens Axboe if (unlikely(err)) 8398c34e2d6SJens Axboe return err; 8408c34e2d6SJens Axboe 841c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8426da61809SMark Fasheh if (ret > 0) { 84317ee4f49SJens Axboe unsigned long nr_pages; 84417ee4f49SJens Axboe 8456da61809SMark Fasheh *ppos += ret; 84617ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8476da61809SMark Fasheh 8486da61809SMark Fasheh /* 8496da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 8506da61809SMark Fasheh * sync it. 8516da61809SMark Fasheh */ 8526da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8536da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8546da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8556da61809SMark Fasheh 8566da61809SMark Fasheh if (err) 8576da61809SMark Fasheh ret = err; 8586da61809SMark Fasheh } 85917ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 8606da61809SMark Fasheh } 8616da61809SMark Fasheh 8626da61809SMark Fasheh return ret; 8636da61809SMark Fasheh } 8646da61809SMark Fasheh 8656da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8666da61809SMark Fasheh 86783f9135bSJens Axboe /** 86883f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8693a326a2cSIngo Molnar * @pipe: pipe info 87083f9135bSJens Axboe * @out: file to write to 871932cc6d4SJens Axboe * @ppos: position in @out 87283f9135bSJens Axboe * @len: number of bytes to splice 87383f9135bSJens Axboe * @flags: splice modifier flags 87483f9135bSJens Axboe * 875932cc6d4SJens Axboe * Description: 87683f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 87783f9135bSJens Axboe * the given pipe inode to the given file. 87883f9135bSJens Axboe * 87983f9135bSJens Axboe */ 8803a326a2cSIngo Molnar ssize_t 8813a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 882cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8835274f052SJens Axboe { 8844f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8858c34e2d6SJens Axboe struct inode *inode = mapping->host; 8863a326a2cSIngo Molnar ssize_t ret; 8878c34e2d6SJens Axboe int err; 8888c34e2d6SJens Axboe 8890f7fc9e4SJosef "Jeff" Sipek err = should_remove_suid(out->f_path.dentry); 8908c34e2d6SJens Axboe if (unlikely(err)) { 8918c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 8920f7fc9e4SJosef "Jeff" Sipek err = __remove_suid(out->f_path.dentry, err); 8938c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8948c34e2d6SJens Axboe if (err) 8958c34e2d6SJens Axboe return err; 8968c34e2d6SJens Axboe } 8973a326a2cSIngo Molnar 89800522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 899a4514ebdSJens Axboe if (ret > 0) { 90017ee4f49SJens Axboe unsigned long nr_pages; 90117ee4f49SJens Axboe 902a4514ebdSJens Axboe *ppos += ret; 90317ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 9044f6f0bd2SJens Axboe 9054f6f0bd2SJens Axboe /* 906a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 907a4514ebdSJens Axboe * sync it. 9084f6f0bd2SJens Axboe */ 909a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 9104f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 911a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 9124f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 9134f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 9144f6f0bd2SJens Axboe 9154f6f0bd2SJens Axboe if (err) 9164f6f0bd2SJens Axboe ret = err; 9174f6f0bd2SJens Axboe } 91817ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 919a4514ebdSJens Axboe } 9204f6f0bd2SJens Axboe 9214f6f0bd2SJens Axboe return ret; 9225274f052SJens Axboe } 9235274f052SJens Axboe 924059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 925059a8f37SJens Axboe 92683f9135bSJens Axboe /** 92783f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 928932cc6d4SJens Axboe * @pipe: pipe to splice from 92983f9135bSJens Axboe * @out: socket to write to 930932cc6d4SJens Axboe * @ppos: position in @out 93183f9135bSJens Axboe * @len: number of bytes to splice 93283f9135bSJens Axboe * @flags: splice modifier flags 93383f9135bSJens Axboe * 934932cc6d4SJens Axboe * Description: 93583f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 93683f9135bSJens Axboe * is involved. 93783f9135bSJens Axboe * 93883f9135bSJens Axboe */ 9393a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 940cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9415274f052SJens Axboe { 94200522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 9435274f052SJens Axboe } 9445274f052SJens Axboe 945059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 946a0f06780SJeff Garzik 94783f9135bSJens Axboe /* 94883f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 94983f9135bSJens Axboe */ 9503a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 951cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9525274f052SJens Axboe { 9535274f052SJens Axboe int ret; 9545274f052SJens Axboe 95549570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9565274f052SJens Axboe return -EINVAL; 9575274f052SJens Axboe 95849570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9595274f052SJens Axboe return -EBADF; 9605274f052SJens Axboe 961cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9625274f052SJens Axboe if (unlikely(ret < 0)) 9635274f052SJens Axboe return ret; 9645274f052SJens Axboe 96529ce2058SJames Morris ret = security_file_permission(out, MAY_WRITE); 96629ce2058SJames Morris if (unlikely(ret < 0)) 96729ce2058SJames Morris return ret; 96829ce2058SJames Morris 969cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9705274f052SJens Axboe } 9715274f052SJens Axboe 97283f9135bSJens Axboe /* 97383f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 97483f9135bSJens Axboe */ 975cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 976cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 977cbb7e577SJens Axboe unsigned int flags) 9785274f052SJens Axboe { 9795274f052SJens Axboe int ret; 9805274f052SJens Axboe 98149570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9825274f052SJens Axboe return -EINVAL; 9835274f052SJens Axboe 98449570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9855274f052SJens Axboe return -EBADF; 9865274f052SJens Axboe 987cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9885274f052SJens Axboe if (unlikely(ret < 0)) 9895274f052SJens Axboe return ret; 9905274f052SJens Axboe 99129ce2058SJames Morris ret = security_file_permission(in, MAY_READ); 99229ce2058SJames Morris if (unlikely(ret < 0)) 99329ce2058SJames Morris return ret; 99429ce2058SJames Morris 995cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9965274f052SJens Axboe } 9975274f052SJens Axboe 998932cc6d4SJens Axboe /** 999932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 1000932cc6d4SJens Axboe * @in: file to splice from 1001932cc6d4SJens Axboe * @sd: actor information on where to splice to 1002932cc6d4SJens Axboe * @actor: handles the data splicing 1003932cc6d4SJens Axboe * 1004932cc6d4SJens Axboe * Description: 1005932cc6d4SJens Axboe * This is a special case helper to splice directly between two 1006932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 1007932cc6d4SJens Axboe * pipe is cached in the process, and reused during the life time of 1008932cc6d4SJens Axboe * that process. 1009932cc6d4SJens Axboe * 1010c66ab6faSJens Axboe */ 1011c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 1012c66ab6faSJens Axboe splice_direct_actor *actor) 1013b92ce558SJens Axboe { 1014b92ce558SJens Axboe struct pipe_inode_info *pipe; 1015b92ce558SJens Axboe long ret, bytes; 1016b92ce558SJens Axboe umode_t i_mode; 1017c66ab6faSJens Axboe size_t len; 1018c66ab6faSJens Axboe int i, flags; 1019b92ce558SJens Axboe 1020b92ce558SJens Axboe /* 1021b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 1022b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 1023b92ce558SJens Axboe * piped splicing for that! 1024b92ce558SJens Axboe */ 10250f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 1026b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 1027b92ce558SJens Axboe return -EINVAL; 1028b92ce558SJens Axboe 1029b92ce558SJens Axboe /* 1030b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 1031b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 1032b92ce558SJens Axboe */ 1033b92ce558SJens Axboe pipe = current->splice_pipe; 103449570e9bSJens Axboe if (unlikely(!pipe)) { 1035b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 1036b92ce558SJens Axboe if (!pipe) 1037b92ce558SJens Axboe return -ENOMEM; 1038b92ce558SJens Axboe 1039b92ce558SJens Axboe /* 1040b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 104100522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 1042b92ce558SJens Axboe * PIPE_READERS appropriately. 1043b92ce558SJens Axboe */ 1044b92ce558SJens Axboe pipe->readers = 1; 1045b92ce558SJens Axboe 1046b92ce558SJens Axboe current->splice_pipe = pipe; 1047b92ce558SJens Axboe } 1048b92ce558SJens Axboe 1049b92ce558SJens Axboe /* 105073d62d83SIngo Molnar * Do the splice. 1051b92ce558SJens Axboe */ 1052b92ce558SJens Axboe ret = 0; 1053b92ce558SJens Axboe bytes = 0; 1054c66ab6faSJens Axboe len = sd->total_len; 1055c66ab6faSJens Axboe flags = sd->flags; 1056c66ab6faSJens Axboe 1057c66ab6faSJens Axboe /* 1058c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1059c66ab6faSJens Axboe */ 1060c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1061b92ce558SJens Axboe 1062b92ce558SJens Axboe while (len) { 106351a92c0fSJens Axboe size_t read_len; 1064b92ce558SJens Axboe 106551a92c0fSJens Axboe ret = do_splice_to(in, &sd->pos, pipe, len, flags); 106651a92c0fSJens Axboe if (unlikely(ret <= 0)) 1067b92ce558SJens Axboe goto out_release; 1068b92ce558SJens Axboe 1069b92ce558SJens Axboe read_len = ret; 1070c66ab6faSJens Axboe sd->total_len = read_len; 1071b92ce558SJens Axboe 1072b92ce558SJens Axboe /* 1073b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1074b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1075b92ce558SJens Axboe * could get stuck data in the internal pipe: 1076b92ce558SJens Axboe */ 1077c66ab6faSJens Axboe ret = actor(pipe, sd); 107851a92c0fSJens Axboe if (unlikely(ret <= 0)) 1079b92ce558SJens Axboe goto out_release; 1080b92ce558SJens Axboe 1081b92ce558SJens Axboe bytes += ret; 1082b92ce558SJens Axboe len -= ret; 1083b92ce558SJens Axboe 108451a92c0fSJens Axboe if (ret < read_len) 108551a92c0fSJens Axboe goto out_release; 1086b92ce558SJens Axboe } 1087b92ce558SJens Axboe 1088b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1089b92ce558SJens Axboe return bytes; 1090b92ce558SJens Axboe 1091b92ce558SJens Axboe out_release: 1092b92ce558SJens Axboe /* 1093b92ce558SJens Axboe * If we did an incomplete transfer we must release 1094b92ce558SJens Axboe * the pipe buffers in question: 1095b92ce558SJens Axboe */ 1096b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1097b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1098b92ce558SJens Axboe 1099b92ce558SJens Axboe if (buf->ops) { 1100b92ce558SJens Axboe buf->ops->release(pipe, buf); 1101b92ce558SJens Axboe buf->ops = NULL; 1102b92ce558SJens Axboe } 1103b92ce558SJens Axboe } 1104b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 1105b92ce558SJens Axboe 1106b92ce558SJens Axboe /* 1107b92ce558SJens Axboe * If we transferred some data, return the number of bytes: 1108b92ce558SJens Axboe */ 1109b92ce558SJens Axboe if (bytes > 0) 1110b92ce558SJens Axboe return bytes; 1111b92ce558SJens Axboe 1112b92ce558SJens Axboe return ret; 1113c66ab6faSJens Axboe 1114c66ab6faSJens Axboe } 1115c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1116c66ab6faSJens Axboe 1117c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1118c66ab6faSJens Axboe struct splice_desc *sd) 1119c66ab6faSJens Axboe { 11206a14b90bSJens Axboe struct file *file = sd->u.file; 1121c66ab6faSJens Axboe 1122c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1123c66ab6faSJens Axboe } 1124c66ab6faSJens Axboe 1125932cc6d4SJens Axboe /** 1126932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1127932cc6d4SJens Axboe * @in: file to splice from 1128932cc6d4SJens Axboe * @ppos: input file offset 1129932cc6d4SJens Axboe * @out: file to splice to 1130932cc6d4SJens Axboe * @len: number of bytes to splice 1131932cc6d4SJens Axboe * @flags: splice modifier flags 1132932cc6d4SJens Axboe * 1133932cc6d4SJens Axboe * Description: 1134932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1135932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1136932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1137932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1138932cc6d4SJens Axboe * 1139932cc6d4SJens Axboe */ 1140c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1141c66ab6faSJens Axboe size_t len, unsigned int flags) 1142c66ab6faSJens Axboe { 1143c66ab6faSJens Axboe struct splice_desc sd = { 1144c66ab6faSJens Axboe .len = len, 1145c66ab6faSJens Axboe .total_len = len, 1146c66ab6faSJens Axboe .flags = flags, 1147c66ab6faSJens Axboe .pos = *ppos, 11486a14b90bSJens Axboe .u.file = out, 1149c66ab6faSJens Axboe }; 115051a92c0fSJens Axboe long ret; 1151c66ab6faSJens Axboe 1152c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 115351a92c0fSJens Axboe if (ret > 0) 115451a92c0fSJens Axboe *ppos += ret; 115551a92c0fSJens Axboe 1156c66ab6faSJens Axboe return ret; 1157b92ce558SJens Axboe } 1158b92ce558SJens Axboe 115983f9135bSJens Axboe /* 1160ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1161ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1162ddac0d39SJens Axboe * pipe. 1163ddac0d39SJens Axboe */ 1164ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1165ddac0d39SJens Axboe { 1166ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1167ddac0d39SJens Axboe return inode->i_pipe; 1168ddac0d39SJens Axboe 1169ddac0d39SJens Axboe return NULL; 1170ddac0d39SJens Axboe } 1171ddac0d39SJens Axboe 1172ddac0d39SJens Axboe /* 117383f9135bSJens Axboe * Determine where to splice to/from. 117483f9135bSJens Axboe */ 1175529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1176529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1177529565dcSIngo Molnar size_t len, unsigned int flags) 11785274f052SJens Axboe { 11793a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1180cbb7e577SJens Axboe loff_t offset, *off; 1181a4514ebdSJens Axboe long ret; 11825274f052SJens Axboe 11830f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1184529565dcSIngo Molnar if (pipe) { 1185529565dcSIngo Molnar if (off_in) 1186529565dcSIngo Molnar return -ESPIPE; 1187b92ce558SJens Axboe if (off_out) { 1188b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1189b92ce558SJens Axboe return -EINVAL; 1190cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1191b92ce558SJens Axboe return -EFAULT; 1192cbb7e577SJens Axboe off = &offset; 1193cbb7e577SJens Axboe } else 1194cbb7e577SJens Axboe off = &out->f_pos; 1195529565dcSIngo Molnar 1196a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1197a4514ebdSJens Axboe 1198a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1199a4514ebdSJens Axboe ret = -EFAULT; 1200a4514ebdSJens Axboe 1201a4514ebdSJens Axboe return ret; 1202529565dcSIngo Molnar } 12035274f052SJens Axboe 12040f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1205529565dcSIngo Molnar if (pipe) { 1206529565dcSIngo Molnar if (off_out) 1207529565dcSIngo Molnar return -ESPIPE; 1208b92ce558SJens Axboe if (off_in) { 1209b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1210b92ce558SJens Axboe return -EINVAL; 1211cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1212b92ce558SJens Axboe return -EFAULT; 1213cbb7e577SJens Axboe off = &offset; 1214cbb7e577SJens Axboe } else 1215cbb7e577SJens Axboe off = &in->f_pos; 1216529565dcSIngo Molnar 1217a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1218a4514ebdSJens Axboe 1219a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1220a4514ebdSJens Axboe ret = -EFAULT; 1221a4514ebdSJens Axboe 1222a4514ebdSJens Axboe return ret; 1223529565dcSIngo Molnar } 12245274f052SJens Axboe 12255274f052SJens Axboe return -EINVAL; 12265274f052SJens Axboe } 12275274f052SJens Axboe 1228912d35f8SJens Axboe /* 1229912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1230912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1231912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1232912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1233912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1234912d35f8SJens Axboe */ 1235912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1236912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 12377afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1238912d35f8SJens Axboe { 1239912d35f8SJens Axboe int buffers = 0, error = 0; 1240912d35f8SJens Axboe 1241912d35f8SJens Axboe /* 1242912d35f8SJens Axboe * It's ok to take the mmap_sem for reading, even 1243912d35f8SJens Axboe * across a "get_user()". 1244912d35f8SJens Axboe */ 1245912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1246912d35f8SJens Axboe 1247912d35f8SJens Axboe while (nr_vecs) { 1248912d35f8SJens Axboe unsigned long off, npages; 1249912d35f8SJens Axboe void __user *base; 1250912d35f8SJens Axboe size_t len; 1251912d35f8SJens Axboe int i; 1252912d35f8SJens Axboe 1253912d35f8SJens Axboe /* 1254912d35f8SJens Axboe * Get user address base and length for this iovec. 1255912d35f8SJens Axboe */ 1256912d35f8SJens Axboe error = get_user(base, &iov->iov_base); 1257912d35f8SJens Axboe if (unlikely(error)) 1258912d35f8SJens Axboe break; 1259912d35f8SJens Axboe error = get_user(len, &iov->iov_len); 1260912d35f8SJens Axboe if (unlikely(error)) 1261912d35f8SJens Axboe break; 1262912d35f8SJens Axboe 1263912d35f8SJens Axboe /* 1264912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1265912d35f8SJens Axboe */ 1266912d35f8SJens Axboe if (unlikely(!len)) 1267912d35f8SJens Axboe break; 1268912d35f8SJens Axboe error = -EFAULT; 1269912d35f8SJens Axboe if (unlikely(!base)) 1270912d35f8SJens Axboe break; 1271912d35f8SJens Axboe 1272912d35f8SJens Axboe /* 1273912d35f8SJens Axboe * Get this base offset and number of pages, then map 1274912d35f8SJens Axboe * in the user pages. 1275912d35f8SJens Axboe */ 1276912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12777afa6fd0SJens Axboe 12787afa6fd0SJens Axboe /* 12797afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12807afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12817afa6fd0SJens Axboe */ 12827afa6fd0SJens Axboe error = -EINVAL; 12837afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12847afa6fd0SJens Axboe break; 12857afa6fd0SJens Axboe 1286912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1287912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1288912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1289912d35f8SJens Axboe 1290912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1291912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1292912d35f8SJens Axboe &pages[buffers], NULL); 1293912d35f8SJens Axboe 1294912d35f8SJens Axboe if (unlikely(error <= 0)) 1295912d35f8SJens Axboe break; 1296912d35f8SJens Axboe 1297912d35f8SJens Axboe /* 1298912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1299912d35f8SJens Axboe */ 1300912d35f8SJens Axboe for (i = 0; i < error; i++) { 13017591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1302912d35f8SJens Axboe 1303912d35f8SJens Axboe partial[buffers].offset = off; 1304912d35f8SJens Axboe partial[buffers].len = plen; 1305912d35f8SJens Axboe 1306912d35f8SJens Axboe off = 0; 1307912d35f8SJens Axboe len -= plen; 1308912d35f8SJens Axboe buffers++; 1309912d35f8SJens Axboe } 1310912d35f8SJens Axboe 1311912d35f8SJens Axboe /* 1312912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1313912d35f8SJens Axboe * means we have to move some of this into a pipe to 1314912d35f8SJens Axboe * be able to continue. 1315912d35f8SJens Axboe */ 1316912d35f8SJens Axboe if (len) 1317912d35f8SJens Axboe break; 1318912d35f8SJens Axboe 1319912d35f8SJens Axboe /* 1320912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1321912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1322912d35f8SJens Axboe * room for. 1323912d35f8SJens Axboe */ 1324912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1325912d35f8SJens Axboe break; 1326912d35f8SJens Axboe 1327912d35f8SJens Axboe nr_vecs--; 1328912d35f8SJens Axboe iov++; 1329912d35f8SJens Axboe } 1330912d35f8SJens Axboe 1331912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1332912d35f8SJens Axboe 1333912d35f8SJens Axboe if (buffers) 1334912d35f8SJens Axboe return buffers; 1335912d35f8SJens Axboe 1336912d35f8SJens Axboe return error; 1337912d35f8SJens Axboe } 1338912d35f8SJens Axboe 13396a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13406a14b90bSJens Axboe struct splice_desc *sd) 13416a14b90bSJens Axboe { 13426a14b90bSJens Axboe char *src; 13436a14b90bSJens Axboe int ret; 13446a14b90bSJens Axboe 1345cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 13466a14b90bSJens Axboe if (unlikely(ret)) 13476a14b90bSJens Axboe return ret; 13486a14b90bSJens Axboe 13496a14b90bSJens Axboe /* 13506a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13516a14b90bSJens Axboe * pages and doing an atomic copy 13526a14b90bSJens Axboe */ 13536a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13546a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13556a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13566a14b90bSJens Axboe sd->len); 13576a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13586a14b90bSJens Axboe if (!ret) { 13596a14b90bSJens Axboe ret = sd->len; 13606a14b90bSJens Axboe goto out; 13616a14b90bSJens Axboe } 13626a14b90bSJens Axboe } 13636a14b90bSJens Axboe 13646a14b90bSJens Axboe /* 13656a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13666a14b90bSJens Axboe */ 13676a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13686a14b90bSJens Axboe 13696a14b90bSJens Axboe ret = sd->len; 13706a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13716a14b90bSJens Axboe ret = -EFAULT; 13726a14b90bSJens Axboe 13736a14b90bSJens Axboe out: 13746a14b90bSJens Axboe if (ret > 0) 13756a14b90bSJens Axboe sd->u.userptr += ret; 13766a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13776a14b90bSJens Axboe return ret; 13786a14b90bSJens Axboe } 13796a14b90bSJens Axboe 13806a14b90bSJens Axboe /* 13816a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13826a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13836a14b90bSJens Axboe */ 13846a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13856a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13866a14b90bSJens Axboe { 13876a14b90bSJens Axboe struct pipe_inode_info *pipe; 13886a14b90bSJens Axboe struct splice_desc sd; 13896a14b90bSJens Axboe ssize_t size; 13906a14b90bSJens Axboe int error; 13916a14b90bSJens Axboe long ret; 13926a14b90bSJens Axboe 13936a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13946a14b90bSJens Axboe if (!pipe) 13956a14b90bSJens Axboe return -EBADF; 13966a14b90bSJens Axboe 13976a14b90bSJens Axboe if (pipe->inode) 13986a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13996a14b90bSJens Axboe 14006a14b90bSJens Axboe error = ret = 0; 14016a14b90bSJens Axboe while (nr_segs) { 14026a14b90bSJens Axboe void __user *base; 14036a14b90bSJens Axboe size_t len; 14046a14b90bSJens Axboe 14056a14b90bSJens Axboe /* 14066a14b90bSJens Axboe * Get user address base and length for this iovec. 14076a14b90bSJens Axboe */ 14086a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 14096a14b90bSJens Axboe if (unlikely(error)) 14106a14b90bSJens Axboe break; 14116a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 14126a14b90bSJens Axboe if (unlikely(error)) 14136a14b90bSJens Axboe break; 14146a14b90bSJens Axboe 14156a14b90bSJens Axboe /* 14166a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 14176a14b90bSJens Axboe */ 14186a14b90bSJens Axboe if (unlikely(!len)) 14196a14b90bSJens Axboe break; 14206a14b90bSJens Axboe if (unlikely(!base)) { 14216a14b90bSJens Axboe error = -EFAULT; 14226a14b90bSJens Axboe break; 14236a14b90bSJens Axboe } 14246a14b90bSJens Axboe 14256a14b90bSJens Axboe sd.len = 0; 14266a14b90bSJens Axboe sd.total_len = len; 14276a14b90bSJens Axboe sd.flags = flags; 14286a14b90bSJens Axboe sd.u.userptr = base; 14296a14b90bSJens Axboe sd.pos = 0; 14306a14b90bSJens Axboe 14316a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 14326a14b90bSJens Axboe if (size < 0) { 14336a14b90bSJens Axboe if (!ret) 14346a14b90bSJens Axboe ret = size; 14356a14b90bSJens Axboe 14366a14b90bSJens Axboe break; 14376a14b90bSJens Axboe } 14386a14b90bSJens Axboe 14396a14b90bSJens Axboe ret += size; 14406a14b90bSJens Axboe 14416a14b90bSJens Axboe if (size < len) 14426a14b90bSJens Axboe break; 14436a14b90bSJens Axboe 14446a14b90bSJens Axboe nr_segs--; 14456a14b90bSJens Axboe iov++; 14466a14b90bSJens Axboe } 14476a14b90bSJens Axboe 14486a14b90bSJens Axboe if (pipe->inode) 14496a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14506a14b90bSJens Axboe 14516a14b90bSJens Axboe if (!ret) 14526a14b90bSJens Axboe ret = error; 14536a14b90bSJens Axboe 14546a14b90bSJens Axboe return ret; 14556a14b90bSJens Axboe } 14566a14b90bSJens Axboe 1457912d35f8SJens Axboe /* 1458912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1459912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1460912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1461912d35f8SJens Axboe */ 14626a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1463912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1464912d35f8SJens Axboe { 1465ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1466912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1467912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1468912d35f8SJens Axboe struct splice_pipe_desc spd = { 1469912d35f8SJens Axboe .pages = pages, 1470912d35f8SJens Axboe .partial = partial, 1471912d35f8SJens Axboe .flags = flags, 1472912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1473912d35f8SJens Axboe }; 1474912d35f8SJens Axboe 14750f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1476ddac0d39SJens Axboe if (!pipe) 1477912d35f8SJens Axboe return -EBADF; 1478912d35f8SJens Axboe 14797afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14807afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1481912d35f8SJens Axboe if (spd.nr_pages <= 0) 1482912d35f8SJens Axboe return spd.nr_pages; 1483912d35f8SJens Axboe 148400522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1485912d35f8SJens Axboe } 1486912d35f8SJens Axboe 14876a14b90bSJens Axboe /* 14886a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14896a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14906a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14916a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14926a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14936a14b90bSJens Axboe * solutions for that: 14946a14b90bSJens Axboe * 14956a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14966a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14976a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14986a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14996a14b90bSJens Axboe * 15006a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 15016a14b90bSJens Axboe * 15026a14b90bSJens Axboe */ 1503912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1504912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1505912d35f8SJens Axboe { 1506912d35f8SJens Axboe struct file *file; 1507912d35f8SJens Axboe long error; 1508912d35f8SJens Axboe int fput; 1509912d35f8SJens Axboe 15106a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 15116a14b90bSJens Axboe return -EINVAL; 15126a14b90bSJens Axboe else if (unlikely(!nr_segs)) 15136a14b90bSJens Axboe return 0; 15146a14b90bSJens Axboe 1515912d35f8SJens Axboe error = -EBADF; 1516912d35f8SJens Axboe file = fget_light(fd, &fput); 1517912d35f8SJens Axboe if (file) { 1518912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 15196a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 15206a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 15216a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1522912d35f8SJens Axboe 1523912d35f8SJens Axboe fput_light(file, fput); 1524912d35f8SJens Axboe } 1525912d35f8SJens Axboe 1526912d35f8SJens Axboe return error; 1527912d35f8SJens Axboe } 1528912d35f8SJens Axboe 1529529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1530529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1531529565dcSIngo Molnar size_t len, unsigned int flags) 15325274f052SJens Axboe { 15335274f052SJens Axboe long error; 15345274f052SJens Axboe struct file *in, *out; 15355274f052SJens Axboe int fput_in, fput_out; 15365274f052SJens Axboe 15375274f052SJens Axboe if (unlikely(!len)) 15385274f052SJens Axboe return 0; 15395274f052SJens Axboe 15405274f052SJens Axboe error = -EBADF; 1541529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 15425274f052SJens Axboe if (in) { 15435274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1544529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15455274f052SJens Axboe if (out) { 15465274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1547529565dcSIngo Molnar error = do_splice(in, off_in, 1548529565dcSIngo Molnar out, off_out, 1549529565dcSIngo Molnar len, flags); 15505274f052SJens Axboe fput_light(out, fput_out); 15515274f052SJens Axboe } 15525274f052SJens Axboe } 15535274f052SJens Axboe 15545274f052SJens Axboe fput_light(in, fput_in); 15555274f052SJens Axboe } 15565274f052SJens Axboe 15575274f052SJens Axboe return error; 15585274f052SJens Axboe } 155970524490SJens Axboe 156070524490SJens Axboe /* 1561aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1562aadd06e5SJens Axboe * return an appropriate error. 1563aadd06e5SJens Axboe */ 1564aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1565aadd06e5SJens Axboe { 1566aadd06e5SJens Axboe int ret; 1567aadd06e5SJens Axboe 1568aadd06e5SJens Axboe /* 1569aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1570aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1571aadd06e5SJens Axboe */ 1572aadd06e5SJens Axboe if (pipe->nrbufs) 1573aadd06e5SJens Axboe return 0; 1574aadd06e5SJens Axboe 1575aadd06e5SJens Axboe ret = 0; 1576aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1577aadd06e5SJens Axboe 1578aadd06e5SJens Axboe while (!pipe->nrbufs) { 1579aadd06e5SJens Axboe if (signal_pending(current)) { 1580aadd06e5SJens Axboe ret = -ERESTARTSYS; 1581aadd06e5SJens Axboe break; 1582aadd06e5SJens Axboe } 1583aadd06e5SJens Axboe if (!pipe->writers) 1584aadd06e5SJens Axboe break; 1585aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1586aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1587aadd06e5SJens Axboe ret = -EAGAIN; 1588aadd06e5SJens Axboe break; 1589aadd06e5SJens Axboe } 1590aadd06e5SJens Axboe } 1591aadd06e5SJens Axboe pipe_wait(pipe); 1592aadd06e5SJens Axboe } 1593aadd06e5SJens Axboe 1594aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1595aadd06e5SJens Axboe return ret; 1596aadd06e5SJens Axboe } 1597aadd06e5SJens Axboe 1598aadd06e5SJens Axboe /* 1599aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1600aadd06e5SJens Axboe * return an appropriate error. 1601aadd06e5SJens Axboe */ 1602aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1603aadd06e5SJens Axboe { 1604aadd06e5SJens Axboe int ret; 1605aadd06e5SJens Axboe 1606aadd06e5SJens Axboe /* 1607aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1608aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1609aadd06e5SJens Axboe */ 1610aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1611aadd06e5SJens Axboe return 0; 1612aadd06e5SJens Axboe 1613aadd06e5SJens Axboe ret = 0; 1614aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1615aadd06e5SJens Axboe 1616aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1617aadd06e5SJens Axboe if (!pipe->readers) { 1618aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1619aadd06e5SJens Axboe ret = -EPIPE; 1620aadd06e5SJens Axboe break; 1621aadd06e5SJens Axboe } 1622aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1623aadd06e5SJens Axboe ret = -EAGAIN; 1624aadd06e5SJens Axboe break; 1625aadd06e5SJens Axboe } 1626aadd06e5SJens Axboe if (signal_pending(current)) { 1627aadd06e5SJens Axboe ret = -ERESTARTSYS; 1628aadd06e5SJens Axboe break; 1629aadd06e5SJens Axboe } 1630aadd06e5SJens Axboe pipe->waiting_writers++; 1631aadd06e5SJens Axboe pipe_wait(pipe); 1632aadd06e5SJens Axboe pipe->waiting_writers--; 1633aadd06e5SJens Axboe } 1634aadd06e5SJens Axboe 1635aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1636aadd06e5SJens Axboe return ret; 1637aadd06e5SJens Axboe } 1638aadd06e5SJens Axboe 1639aadd06e5SJens Axboe /* 164070524490SJens Axboe * Link contents of ipipe to opipe. 164170524490SJens Axboe */ 164270524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 164370524490SJens Axboe struct pipe_inode_info *opipe, 164470524490SJens Axboe size_t len, unsigned int flags) 164570524490SJens Axboe { 164670524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1647aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 164870524490SJens Axboe 164970524490SJens Axboe /* 165070524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 165170524490SJens Axboe * grabbing by inode address. Otherwise two different processes 165270524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 165370524490SJens Axboe */ 165462752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 165570524490SJens Axboe 1656aadd06e5SJens Axboe do { 165770524490SJens Axboe if (!opipe->readers) { 165870524490SJens Axboe send_sig(SIGPIPE, current, 0); 165970524490SJens Axboe if (!ret) 166070524490SJens Axboe ret = -EPIPE; 166170524490SJens Axboe break; 166270524490SJens Axboe } 166370524490SJens Axboe 166470524490SJens Axboe /* 1665aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1666aadd06e5SJens Axboe * output room, break. 166770524490SJens Axboe */ 1668aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1669aadd06e5SJens Axboe break; 1670aadd06e5SJens Axboe 1671aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1672aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 167370524490SJens Axboe 167470524490SJens Axboe /* 167570524490SJens Axboe * Get a reference to this pipe buffer, 167670524490SJens Axboe * so we can copy the contents over. 167770524490SJens Axboe */ 167870524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 167970524490SJens Axboe 168070524490SJens Axboe obuf = opipe->bufs + nbuf; 168170524490SJens Axboe *obuf = *ibuf; 168270524490SJens Axboe 16837afa6fd0SJens Axboe /* 16847afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16857afa6fd0SJens Axboe * prevent multiple steals of this page. 16867afa6fd0SJens Axboe */ 16877afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16887afa6fd0SJens Axboe 168970524490SJens Axboe if (obuf->len > len) 169070524490SJens Axboe obuf->len = len; 169170524490SJens Axboe 169270524490SJens Axboe opipe->nrbufs++; 169370524490SJens Axboe ret += obuf->len; 169470524490SJens Axboe len -= obuf->len; 1695aadd06e5SJens Axboe i++; 1696aadd06e5SJens Axboe } while (len); 169770524490SJens Axboe 169862752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 169970524490SJens Axboe 1700aadd06e5SJens Axboe /* 1701aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1702aadd06e5SJens Axboe */ 1703aadd06e5SJens Axboe if (ret > 0) { 170470524490SJens Axboe smp_mb(); 170570524490SJens Axboe if (waitqueue_active(&opipe->wait)) 170670524490SJens Axboe wake_up_interruptible(&opipe->wait); 170770524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 170870524490SJens Axboe } 170970524490SJens Axboe 171070524490SJens Axboe return ret; 171170524490SJens Axboe } 171270524490SJens Axboe 171370524490SJens Axboe /* 171470524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 171570524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 171670524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 171770524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 171870524490SJens Axboe */ 171970524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 172070524490SJens Axboe unsigned int flags) 172170524490SJens Axboe { 17220f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 17230f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1724aadd06e5SJens Axboe int ret = -EINVAL; 172570524490SJens Axboe 172670524490SJens Axboe /* 1727aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1728aadd06e5SJens Axboe * copying the data. 172970524490SJens Axboe */ 1730aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1731aadd06e5SJens Axboe /* 1732aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1733aadd06e5SJens Axboe * ordering doesn't really matter. 1734aadd06e5SJens Axboe */ 1735aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1736aadd06e5SJens Axboe if (!ret) { 1737aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 1738aadd06e5SJens Axboe if (!ret) { 1739aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1740aadd06e5SJens Axboe if (!ret && (flags & SPLICE_F_NONBLOCK)) 1741aadd06e5SJens Axboe ret = -EAGAIN; 1742aadd06e5SJens Axboe } 1743aadd06e5SJens Axboe } 1744aadd06e5SJens Axboe } 174570524490SJens Axboe 1746aadd06e5SJens Axboe return ret; 174770524490SJens Axboe } 174870524490SJens Axboe 174970524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 175070524490SJens Axboe { 175170524490SJens Axboe struct file *in; 175270524490SJens Axboe int error, fput_in; 175370524490SJens Axboe 175470524490SJens Axboe if (unlikely(!len)) 175570524490SJens Axboe return 0; 175670524490SJens Axboe 175770524490SJens Axboe error = -EBADF; 175870524490SJens Axboe in = fget_light(fdin, &fput_in); 175970524490SJens Axboe if (in) { 176070524490SJens Axboe if (in->f_mode & FMODE_READ) { 176170524490SJens Axboe int fput_out; 176270524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 176370524490SJens Axboe 176470524490SJens Axboe if (out) { 176570524490SJens Axboe if (out->f_mode & FMODE_WRITE) 176670524490SJens Axboe error = do_tee(in, out, len, flags); 176770524490SJens Axboe fput_light(out, fput_out); 176870524490SJens Axboe } 176970524490SJens Axboe } 177070524490SJens Axboe fput_light(in, fput_in); 177170524490SJens Axboe } 177270524490SJens Axboe 177370524490SJens Axboe return error; 177470524490SJens Axboe } 1775