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) 257bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2585274f052SJens Axboe 2595274f052SJens Axboe return ret; 2605274f052SJens Axboe } 2615274f052SJens Axboe 262bbdfc2f7SJens Axboe static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 263bbdfc2f7SJens Axboe { 264bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 265bbdfc2f7SJens Axboe } 266bbdfc2f7SJens Axboe 2673a326a2cSIngo Molnar static int 268cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 269cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 270cbb7e577SJens Axboe unsigned int flags) 2715274f052SJens Axboe { 2725274f052SJens Axboe struct address_space *mapping = in->f_mapping; 273d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 27416c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 275912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2765274f052SJens Axboe struct page *page; 27791ad66efSJens Axboe pgoff_t index, end_index; 27891ad66efSJens Axboe loff_t isize; 279eb20796bSJens Axboe int error, page_nr; 280912d35f8SJens Axboe struct splice_pipe_desc spd = { 281912d35f8SJens Axboe .pages = pages, 282912d35f8SJens Axboe .partial = partial, 283912d35f8SJens Axboe .flags = flags, 284912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 285bbdfc2f7SJens Axboe .spd_release = spd_release_page, 286912d35f8SJens Axboe }; 2875274f052SJens Axboe 288cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 289912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 290d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 291d8983910SFengguang Wu nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); 2925274f052SJens Axboe 2935274f052SJens Axboe /* 294eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29582aa5d61SJens Axboe */ 296eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 297431a4820SFengguang Wu index += spd.nr_pages; 298eb20796bSJens Axboe 2995274f052SJens Axboe /* 300eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 301431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 302eb20796bSJens Axboe */ 303431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 304cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 305cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 306431a4820SFengguang Wu 307932cc6d4SJens Axboe error = 0; 308eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 309eb20796bSJens Axboe /* 310eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 311eb20796bSJens Axboe * the first hole. 3125274f052SJens Axboe */ 3137480a904SJens Axboe page = find_get_page(mapping, index); 3147480a904SJens Axboe if (!page) { 315e27dedd8SJens Axboe /* 316eb20796bSJens Axboe * page didn't exist, allocate one. 3177480a904SJens Axboe */ 3187480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3195274f052SJens Axboe if (!page) 3205274f052SJens Axboe break; 3215274f052SJens Axboe 3227480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3232ae88149SNick Piggin GFP_KERNEL); 3245274f052SJens Axboe if (unlikely(error)) { 3255274f052SJens Axboe page_cache_release(page); 326a0548871SJens Axboe if (error == -EEXIST) 327a0548871SJens Axboe continue; 3285274f052SJens Axboe break; 3295274f052SJens Axboe } 330eb20796bSJens Axboe /* 331eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 332eb20796bSJens Axboe * to avoid convoluting the logic below even more. 333eb20796bSJens Axboe */ 334eb20796bSJens Axboe unlock_page(page); 3355274f052SJens Axboe } 3367480a904SJens Axboe 337eb20796bSJens Axboe pages[spd.nr_pages++] = page; 338eb20796bSJens Axboe index++; 339eb20796bSJens Axboe } 340eb20796bSJens Axboe 341eb20796bSJens Axboe /* 342eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 343eb20796bSJens Axboe * pages, fill in the partial map, etc. 344eb20796bSJens Axboe */ 345eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 346eb20796bSJens Axboe nr_pages = spd.nr_pages; 347eb20796bSJens Axboe spd.nr_pages = 0; 348eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 349eb20796bSJens Axboe unsigned int this_len; 350eb20796bSJens Axboe 351eb20796bSJens Axboe if (!len) 352eb20796bSJens Axboe break; 353eb20796bSJens Axboe 354eb20796bSJens Axboe /* 355eb20796bSJens Axboe * this_len is the max we'll use from this page 356eb20796bSJens Axboe */ 357eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 358eb20796bSJens Axboe page = pages[page_nr]; 359eb20796bSJens Axboe 360a08a166fSFengguang Wu if (PageReadahead(page)) 361cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 362d8983910SFengguang Wu page, index, req_pages - page_nr); 363a08a166fSFengguang Wu 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++]); 456f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 457eb20796bSJens Axboe 458912d35f8SJens Axboe if (spd.nr_pages) 45900522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 46016c523ddSJens Axboe 4617480a904SJens Axboe return error; 4625274f052SJens Axboe } 4635274f052SJens Axboe 46483f9135bSJens Axboe /** 46583f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46683f9135bSJens Axboe * @in: file to splice from 467932cc6d4SJens Axboe * @ppos: position in @in 46883f9135bSJens Axboe * @pipe: pipe to splice to 46983f9135bSJens Axboe * @len: number of bytes to splice 47083f9135bSJens Axboe * @flags: splice modifier flags 47183f9135bSJens Axboe * 472932cc6d4SJens Axboe * Description: 473932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 474932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 475932cc6d4SJens Axboe * a readpage() hook. 476932cc6d4SJens Axboe * 47783f9135bSJens Axboe */ 478cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 479cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 480cbb7e577SJens Axboe unsigned int flags) 4815274f052SJens Axboe { 4825274f052SJens Axboe ssize_t spliced; 4835274f052SJens Axboe int ret; 484d366d398SJens Axboe loff_t isize, left; 485d366d398SJens Axboe 486d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 487d366d398SJens Axboe if (unlikely(*ppos >= isize)) 488d366d398SJens Axboe return 0; 489d366d398SJens Axboe 490d366d398SJens Axboe left = isize - *ppos; 491d366d398SJens Axboe if (unlikely(left < len)) 492d366d398SJens Axboe len = left; 4935274f052SJens Axboe 4945274f052SJens Axboe ret = 0; 4955274f052SJens Axboe spliced = 0; 49651a92c0fSJens Axboe while (len && !spliced) { 497cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4985274f052SJens Axboe 499c4f895cbSJens Axboe if (ret < 0) 5005274f052SJens Axboe break; 501c4f895cbSJens Axboe else if (!ret) { 502c4f895cbSJens Axboe if (spliced) 503c4f895cbSJens Axboe break; 504c4f895cbSJens Axboe if (flags & SPLICE_F_NONBLOCK) { 505c4f895cbSJens Axboe ret = -EAGAIN; 506c4f895cbSJens Axboe break; 507c4f895cbSJens Axboe } 508c4f895cbSJens Axboe } 5095274f052SJens Axboe 510cbb7e577SJens Axboe *ppos += ret; 5115274f052SJens Axboe len -= ret; 5125274f052SJens Axboe spliced += ret; 5135274f052SJens Axboe } 5145274f052SJens Axboe 5155274f052SJens Axboe if (spliced) 5165274f052SJens Axboe return spliced; 5175274f052SJens Axboe 5185274f052SJens Axboe return ret; 5195274f052SJens Axboe } 5205274f052SJens Axboe 521059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 522059a8f37SJens Axboe 5235274f052SJens Axboe /* 5244f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 525016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5265274f052SJens Axboe */ 52776ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5285274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5295274f052SJens Axboe { 5306a14b90bSJens Axboe struct file *file = sd->u.file; 5315274f052SJens Axboe loff_t pos = sd->pos; 532f84d7519SJens Axboe int ret, more; 5335274f052SJens Axboe 534cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 535f84d7519SJens Axboe if (!ret) { 536b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5375274f052SJens Axboe 538f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 539f84d7519SJens Axboe sd->len, &pos, more); 540f84d7519SJens Axboe } 5415274f052SJens Axboe 542016b661eSJens Axboe return ret; 5435274f052SJens Axboe } 5445274f052SJens Axboe 5455274f052SJens Axboe /* 5465274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5475274f052SJens Axboe * basically three cases: 5485274f052SJens Axboe * 5495274f052SJens Axboe * - Destination page already exists in the address space and there 5505274f052SJens Axboe * are users of it. For that case we have no other option that 5515274f052SJens Axboe * copying the data. Tough luck. 5525274f052SJens Axboe * - Destination page already exists in the address space, but there 5535274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5545274f052SJens Axboe * through to last case. 5555274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5565274f052SJens Axboe * the page cache and avoid the copy. 5575274f052SJens Axboe * 55883f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55983f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 56083f9135bSJens Axboe * file address space page cache. This is possible if no one else has 56183f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 56283f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 56383f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5645274f052SJens Axboe */ 56576ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5665274f052SJens Axboe struct splice_desc *sd) 5675274f052SJens Axboe { 5686a14b90bSJens Axboe struct file *file = sd->u.file; 5695274f052SJens Axboe struct address_space *mapping = file->f_mapping; 570016b661eSJens Axboe unsigned int offset, this_len; 5715274f052SJens Axboe struct page *page; 572afddba49SNick Piggin void *fsdata; 5733e7ee3e7SJens Axboe int ret; 5745274f052SJens Axboe 5755274f052SJens Axboe /* 57649d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5775274f052SJens Axboe */ 578cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 579f84d7519SJens Axboe if (unlikely(ret)) 580f84d7519SJens Axboe return ret; 5815274f052SJens Axboe 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 588afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 589afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 5909e0267c2SJens Axboe if (unlikely(ret)) 591afddba49SNick Piggin goto out; 5925274f052SJens Axboe 5930568b409SJens Axboe if (buf->page != page) { 594f84d7519SJens Axboe /* 595f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 596f84d7519SJens Axboe */ 59776ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 598f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 5995abc97aaSJens Axboe 600016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 6015274f052SJens Axboe flush_dcache_page(page); 602f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 60376ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 6045abc97aaSJens Axboe } 605afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 606afddba49SNick Piggin page, fsdata); 6070568b409SJens Axboe out: 6085274f052SJens Axboe return ret; 6095274f052SJens Axboe } 6105274f052SJens Axboe 611932cc6d4SJens Axboe /** 612932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 613932cc6d4SJens Axboe * @pipe: pipe to splice from 614932cc6d4SJens Axboe * @sd: information to @actor 615932cc6d4SJens Axboe * @actor: handler that splices the data 616932cc6d4SJens Axboe * 617932cc6d4SJens Axboe * Description: 618932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 619932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 620932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 621932cc6d4SJens Axboe * pipe_to_user. 622932cc6d4SJens Axboe * 62383f9135bSJens Axboe */ 624c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 625c66ab6faSJens Axboe splice_actor *actor) 6265274f052SJens Axboe { 6275274f052SJens Axboe int ret, do_wakeup, err; 6285274f052SJens Axboe 6295274f052SJens Axboe ret = 0; 6305274f052SJens Axboe do_wakeup = 0; 6315274f052SJens Axboe 6325274f052SJens Axboe for (;;) { 6336f767b04SJens Axboe if (pipe->nrbufs) { 6346f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 635d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6365274f052SJens Axboe 637c66ab6faSJens Axboe sd->len = buf->len; 638c66ab6faSJens Axboe if (sd->len > sd->total_len) 639c66ab6faSJens Axboe sd->len = sd->total_len; 6405274f052SJens Axboe 641c66ab6faSJens Axboe err = actor(pipe, buf, sd); 642016b661eSJens Axboe if (err <= 0) { 6435274f052SJens Axboe if (!ret && err != -ENODATA) 6445274f052SJens Axboe ret = err; 6455274f052SJens Axboe 6465274f052SJens Axboe break; 6475274f052SJens Axboe } 6485274f052SJens Axboe 649016b661eSJens Axboe ret += err; 650016b661eSJens Axboe buf->offset += err; 651016b661eSJens Axboe buf->len -= err; 652016b661eSJens Axboe 653c66ab6faSJens Axboe sd->len -= err; 654c66ab6faSJens Axboe sd->pos += err; 655c66ab6faSJens Axboe sd->total_len -= err; 656c66ab6faSJens Axboe if (sd->len) 657016b661eSJens Axboe continue; 65873d62d83SIngo Molnar 6595274f052SJens Axboe if (!buf->len) { 6605274f052SJens Axboe buf->ops = NULL; 6613a326a2cSIngo Molnar ops->release(pipe, buf); 6626f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 6636f767b04SJens Axboe pipe->nrbufs--; 6646f767b04SJens Axboe if (pipe->inode) 6655274f052SJens Axboe do_wakeup = 1; 6665274f052SJens Axboe } 6675274f052SJens Axboe 668c66ab6faSJens Axboe if (!sd->total_len) 6695274f052SJens Axboe break; 6705274f052SJens Axboe } 6715274f052SJens Axboe 6726f767b04SJens Axboe if (pipe->nrbufs) 6735274f052SJens Axboe continue; 6743a326a2cSIngo Molnar if (!pipe->writers) 6755274f052SJens Axboe break; 6763a326a2cSIngo Molnar if (!pipe->waiting_writers) { 6775274f052SJens Axboe if (ret) 6785274f052SJens Axboe break; 6795274f052SJens Axboe } 6805274f052SJens Axboe 681c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 68229e35094SLinus Torvalds if (!ret) 68329e35094SLinus Torvalds ret = -EAGAIN; 68429e35094SLinus Torvalds break; 68529e35094SLinus Torvalds } 68629e35094SLinus Torvalds 6875274f052SJens Axboe if (signal_pending(current)) { 6885274f052SJens Axboe if (!ret) 6895274f052SJens Axboe ret = -ERESTARTSYS; 6905274f052SJens Axboe break; 6915274f052SJens Axboe } 6925274f052SJens Axboe 6935274f052SJens Axboe if (do_wakeup) { 694c0bd1f65SJens Axboe smp_mb(); 6953a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6963a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 6973a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 6985274f052SJens Axboe do_wakeup = 0; 6995274f052SJens Axboe } 7005274f052SJens Axboe 7013a326a2cSIngo Molnar pipe_wait(pipe); 7025274f052SJens Axboe } 7035274f052SJens Axboe 7045274f052SJens Axboe if (do_wakeup) { 705c0bd1f65SJens Axboe smp_mb(); 7063a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 7073a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7083a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7095274f052SJens Axboe } 7105274f052SJens Axboe 7115274f052SJens Axboe return ret; 7125274f052SJens Axboe } 71340bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7145274f052SJens Axboe 715932cc6d4SJens Axboe /** 716932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 717932cc6d4SJens Axboe * @pipe: pipe to splice from 718932cc6d4SJens Axboe * @out: file to splice to 719932cc6d4SJens Axboe * @ppos: position in @out 720932cc6d4SJens Axboe * @len: how many bytes to splice 721932cc6d4SJens Axboe * @flags: splice modifier flags 722932cc6d4SJens Axboe * @actor: handler that splices the data 723932cc6d4SJens Axboe * 724932cc6d4SJens Axboe * Description: 725932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 726932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 727932cc6d4SJens Axboe * 728932cc6d4SJens Axboe */ 7296da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7306da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7316da61809SMark Fasheh splice_actor *actor) 7326da61809SMark Fasheh { 7336da61809SMark Fasheh ssize_t ret; 7346da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 735c66ab6faSJens Axboe struct splice_desc sd = { 736c66ab6faSJens Axboe .total_len = len, 737c66ab6faSJens Axboe .flags = flags, 738c66ab6faSJens Axboe .pos = *ppos, 7396a14b90bSJens Axboe .u.file = out, 740c66ab6faSJens Axboe }; 7416da61809SMark Fasheh 7426da61809SMark Fasheh /* 7436da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7446da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7456da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7466da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7476da61809SMark Fasheh */ 7486da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 749c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7506da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7516da61809SMark Fasheh 7526da61809SMark Fasheh return ret; 7536da61809SMark Fasheh } 7546da61809SMark Fasheh 7556da61809SMark Fasheh /** 7566da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7576da61809SMark Fasheh * @pipe: pipe info 7586da61809SMark Fasheh * @out: file to write to 759932cc6d4SJens Axboe * @ppos: position in @out 7606da61809SMark Fasheh * @len: number of bytes to splice 7616da61809SMark Fasheh * @flags: splice modifier flags 7626da61809SMark Fasheh * 763932cc6d4SJens Axboe * Description: 7646da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7656da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7666da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7676da61809SMark Fasheh * 7686da61809SMark Fasheh */ 7696da61809SMark Fasheh ssize_t 7706da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 7716da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 7726da61809SMark Fasheh { 7736da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 7746da61809SMark Fasheh struct inode *inode = mapping->host; 775c66ab6faSJens Axboe struct splice_desc sd = { 776c66ab6faSJens Axboe .total_len = len, 777c66ab6faSJens Axboe .flags = flags, 778c66ab6faSJens Axboe .pos = *ppos, 7796a14b90bSJens Axboe .u.file = out, 780c66ab6faSJens Axboe }; 7816da61809SMark Fasheh ssize_t ret; 7826da61809SMark Fasheh int err; 7836da61809SMark Fasheh 7840f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 7858c34e2d6SJens Axboe if (unlikely(err)) 7868c34e2d6SJens Axboe return err; 7878c34e2d6SJens Axboe 788c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 7896da61809SMark Fasheh if (ret > 0) { 79017ee4f49SJens Axboe unsigned long nr_pages; 79117ee4f49SJens Axboe 7926da61809SMark Fasheh *ppos += ret; 79317ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 7946da61809SMark Fasheh 7956da61809SMark Fasheh /* 7966da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 7976da61809SMark Fasheh * sync it. 7986da61809SMark Fasheh */ 7996da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8006da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 8016da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 8026da61809SMark Fasheh 8036da61809SMark Fasheh if (err) 8046da61809SMark Fasheh ret = err; 8056da61809SMark Fasheh } 80617ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 8076da61809SMark Fasheh } 8086da61809SMark Fasheh 8096da61809SMark Fasheh return ret; 8106da61809SMark Fasheh } 8116da61809SMark Fasheh 8126da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8136da61809SMark Fasheh 81483f9135bSJens Axboe /** 81583f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8163a326a2cSIngo Molnar * @pipe: pipe info 81783f9135bSJens Axboe * @out: file to write to 818932cc6d4SJens Axboe * @ppos: position in @out 81983f9135bSJens Axboe * @len: number of bytes to splice 82083f9135bSJens Axboe * @flags: splice modifier flags 82183f9135bSJens Axboe * 822932cc6d4SJens Axboe * Description: 82383f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 82483f9135bSJens Axboe * the given pipe inode to the given file. 82583f9135bSJens Axboe * 82683f9135bSJens Axboe */ 8273a326a2cSIngo Molnar ssize_t 8283a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 829cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8305274f052SJens Axboe { 8314f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8328c34e2d6SJens Axboe struct inode *inode = mapping->host; 833b5376771SSerge E. Hallyn int killsuid, killpriv; 8343a326a2cSIngo Molnar ssize_t ret; 835b5376771SSerge E. Hallyn int err = 0; 8368c34e2d6SJens Axboe 837b5376771SSerge E. Hallyn killpriv = security_inode_need_killpriv(out->f_path.dentry); 838b5376771SSerge E. Hallyn killsuid = should_remove_suid(out->f_path.dentry); 839b5376771SSerge E. Hallyn if (unlikely(killsuid || killpriv)) { 8408c34e2d6SJens Axboe mutex_lock(&inode->i_mutex); 841b5376771SSerge E. Hallyn if (killpriv) 842b5376771SSerge E. Hallyn err = security_inode_killpriv(out->f_path.dentry); 843b5376771SSerge E. Hallyn if (!err && killsuid) 844b5376771SSerge E. Hallyn err = __remove_suid(out->f_path.dentry, killsuid); 8458c34e2d6SJens Axboe mutex_unlock(&inode->i_mutex); 8468c34e2d6SJens Axboe if (err) 8478c34e2d6SJens Axboe return err; 8488c34e2d6SJens Axboe } 8493a326a2cSIngo Molnar 85000522fb4SJens Axboe ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); 851a4514ebdSJens Axboe if (ret > 0) { 85217ee4f49SJens Axboe unsigned long nr_pages; 85317ee4f49SJens Axboe 854a4514ebdSJens Axboe *ppos += ret; 85517ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8564f6f0bd2SJens Axboe 8574f6f0bd2SJens Axboe /* 858a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 859a4514ebdSJens Axboe * sync it. 8604f6f0bd2SJens Axboe */ 861a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8624f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 863a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8644f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8654f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8664f6f0bd2SJens Axboe 8674f6f0bd2SJens Axboe if (err) 8684f6f0bd2SJens Axboe ret = err; 8694f6f0bd2SJens Axboe } 87017ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 871a4514ebdSJens Axboe } 8724f6f0bd2SJens Axboe 8734f6f0bd2SJens Axboe return ret; 8745274f052SJens Axboe } 8755274f052SJens Axboe 876059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 877059a8f37SJens Axboe 87883f9135bSJens Axboe /** 87983f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 880932cc6d4SJens Axboe * @pipe: pipe to splice from 88183f9135bSJens Axboe * @out: socket to write to 882932cc6d4SJens Axboe * @ppos: position in @out 88383f9135bSJens Axboe * @len: number of bytes to splice 88483f9135bSJens Axboe * @flags: splice modifier flags 88583f9135bSJens Axboe * 886932cc6d4SJens Axboe * Description: 88783f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 88883f9135bSJens Axboe * is involved. 88983f9135bSJens Axboe * 89083f9135bSJens Axboe */ 8913a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 892cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8935274f052SJens Axboe { 89400522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8955274f052SJens Axboe } 8965274f052SJens Axboe 897059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 898a0f06780SJeff Garzik 89983f9135bSJens Axboe /* 90083f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 90183f9135bSJens Axboe */ 9023a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 903cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9045274f052SJens Axboe { 9055274f052SJens Axboe int ret; 9065274f052SJens Axboe 90749570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 9085274f052SJens Axboe return -EINVAL; 9095274f052SJens Axboe 91049570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9115274f052SJens Axboe return -EBADF; 9125274f052SJens Axboe 913cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9145274f052SJens Axboe if (unlikely(ret < 0)) 9155274f052SJens Axboe return ret; 9165274f052SJens Axboe 917cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9185274f052SJens Axboe } 9195274f052SJens Axboe 92083f9135bSJens Axboe /* 92183f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 92283f9135bSJens Axboe */ 923cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 924cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 925cbb7e577SJens Axboe unsigned int flags) 9265274f052SJens Axboe { 9275274f052SJens Axboe int ret; 9285274f052SJens Axboe 92949570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9305274f052SJens Axboe return -EINVAL; 9315274f052SJens Axboe 93249570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9335274f052SJens Axboe return -EBADF; 9345274f052SJens Axboe 935cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9365274f052SJens Axboe if (unlikely(ret < 0)) 9375274f052SJens Axboe return ret; 9385274f052SJens Axboe 939cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9405274f052SJens Axboe } 9415274f052SJens Axboe 942932cc6d4SJens Axboe /** 943932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 944932cc6d4SJens Axboe * @in: file to splice from 945932cc6d4SJens Axboe * @sd: actor information on where to splice to 946932cc6d4SJens Axboe * @actor: handles the data splicing 947932cc6d4SJens Axboe * 948932cc6d4SJens Axboe * Description: 949932cc6d4SJens Axboe * This is a special case helper to splice directly between two 950932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 951932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 952932cc6d4SJens Axboe * that process. 953932cc6d4SJens Axboe * 954c66ab6faSJens Axboe */ 955c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 956c66ab6faSJens Axboe splice_direct_actor *actor) 957b92ce558SJens Axboe { 958b92ce558SJens Axboe struct pipe_inode_info *pipe; 959b92ce558SJens Axboe long ret, bytes; 960b92ce558SJens Axboe umode_t i_mode; 961c66ab6faSJens Axboe size_t len; 962c66ab6faSJens Axboe int i, flags; 963b92ce558SJens Axboe 964b92ce558SJens Axboe /* 965b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 966b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 967b92ce558SJens Axboe * piped splicing for that! 968b92ce558SJens Axboe */ 9690f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 970b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 971b92ce558SJens Axboe return -EINVAL; 972b92ce558SJens Axboe 973b92ce558SJens Axboe /* 974b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 975b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 976b92ce558SJens Axboe */ 977b92ce558SJens Axboe pipe = current->splice_pipe; 97849570e9bSJens Axboe if (unlikely(!pipe)) { 979b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 980b92ce558SJens Axboe if (!pipe) 981b92ce558SJens Axboe return -ENOMEM; 982b92ce558SJens Axboe 983b92ce558SJens Axboe /* 984b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 98500522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 986b92ce558SJens Axboe * PIPE_READERS appropriately. 987b92ce558SJens Axboe */ 988b92ce558SJens Axboe pipe->readers = 1; 989b92ce558SJens Axboe 990b92ce558SJens Axboe current->splice_pipe = pipe; 991b92ce558SJens Axboe } 992b92ce558SJens Axboe 993b92ce558SJens Axboe /* 99473d62d83SIngo Molnar * Do the splice. 995b92ce558SJens Axboe */ 996b92ce558SJens Axboe ret = 0; 997b92ce558SJens Axboe bytes = 0; 998c66ab6faSJens Axboe len = sd->total_len; 999c66ab6faSJens Axboe flags = sd->flags; 1000c66ab6faSJens Axboe 1001c66ab6faSJens Axboe /* 1002c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1003c66ab6faSJens Axboe */ 1004c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1005b92ce558SJens Axboe 1006b92ce558SJens Axboe while (len) { 100751a92c0fSJens Axboe size_t read_len; 1008bcd4f3acSJens Axboe loff_t pos = sd->pos; 1009b92ce558SJens Axboe 1010bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 101151a92c0fSJens Axboe if (unlikely(ret <= 0)) 1012b92ce558SJens Axboe goto out_release; 1013b92ce558SJens Axboe 1014b92ce558SJens Axboe read_len = ret; 1015c66ab6faSJens Axboe sd->total_len = read_len; 1016b92ce558SJens Axboe 1017b92ce558SJens Axboe /* 1018b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1019b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1020b92ce558SJens Axboe * could get stuck data in the internal pipe: 1021b92ce558SJens Axboe */ 1022c66ab6faSJens Axboe ret = actor(pipe, sd); 102351a92c0fSJens Axboe if (unlikely(ret <= 0)) 1024b92ce558SJens Axboe goto out_release; 1025b92ce558SJens Axboe 1026b92ce558SJens Axboe bytes += ret; 1027b92ce558SJens Axboe len -= ret; 1028bcd4f3acSJens Axboe sd->pos = pos; 1029b92ce558SJens Axboe 103051a92c0fSJens Axboe if (ret < read_len) 103151a92c0fSJens Axboe goto out_release; 1032b92ce558SJens Axboe } 1033b92ce558SJens Axboe 10349e97198dSJens Axboe done: 1035b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10369e97198dSJens Axboe file_accessed(in); 1037b92ce558SJens Axboe return bytes; 1038b92ce558SJens Axboe 1039b92ce558SJens Axboe out_release: 1040b92ce558SJens Axboe /* 1041b92ce558SJens Axboe * If we did an incomplete transfer we must release 1042b92ce558SJens Axboe * the pipe buffers in question: 1043b92ce558SJens Axboe */ 1044b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1045b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1046b92ce558SJens Axboe 1047b92ce558SJens Axboe if (buf->ops) { 1048b92ce558SJens Axboe buf->ops->release(pipe, buf); 1049b92ce558SJens Axboe buf->ops = NULL; 1050b92ce558SJens Axboe } 1051b92ce558SJens Axboe } 1052b92ce558SJens Axboe 10539e97198dSJens Axboe if (!bytes) 10549e97198dSJens Axboe bytes = ret; 1055b92ce558SJens Axboe 10569e97198dSJens Axboe goto done; 1057c66ab6faSJens Axboe } 1058c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1059c66ab6faSJens Axboe 1060c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1061c66ab6faSJens Axboe struct splice_desc *sd) 1062c66ab6faSJens Axboe { 10636a14b90bSJens Axboe struct file *file = sd->u.file; 1064c66ab6faSJens Axboe 1065c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1066c66ab6faSJens Axboe } 1067c66ab6faSJens Axboe 1068932cc6d4SJens Axboe /** 1069932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1070932cc6d4SJens Axboe * @in: file to splice from 1071932cc6d4SJens Axboe * @ppos: input file offset 1072932cc6d4SJens Axboe * @out: file to splice to 1073932cc6d4SJens Axboe * @len: number of bytes to splice 1074932cc6d4SJens Axboe * @flags: splice modifier flags 1075932cc6d4SJens Axboe * 1076932cc6d4SJens Axboe * Description: 1077932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1078932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1079932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1080932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1081932cc6d4SJens Axboe * 1082932cc6d4SJens Axboe */ 1083c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1084c66ab6faSJens Axboe size_t len, unsigned int flags) 1085c66ab6faSJens Axboe { 1086c66ab6faSJens Axboe struct splice_desc sd = { 1087c66ab6faSJens Axboe .len = len, 1088c66ab6faSJens Axboe .total_len = len, 1089c66ab6faSJens Axboe .flags = flags, 1090c66ab6faSJens Axboe .pos = *ppos, 10916a14b90bSJens Axboe .u.file = out, 1092c66ab6faSJens Axboe }; 109351a92c0fSJens Axboe long ret; 1094c66ab6faSJens Axboe 1095c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 109651a92c0fSJens Axboe if (ret > 0) 109751a92c0fSJens Axboe *ppos += ret; 109851a92c0fSJens Axboe 1099c66ab6faSJens Axboe return ret; 1100b92ce558SJens Axboe } 1101b92ce558SJens Axboe 110283f9135bSJens Axboe /* 1103ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1104ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1105ddac0d39SJens Axboe * pipe. 1106ddac0d39SJens Axboe */ 1107ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1108ddac0d39SJens Axboe { 1109ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1110ddac0d39SJens Axboe return inode->i_pipe; 1111ddac0d39SJens Axboe 1112ddac0d39SJens Axboe return NULL; 1113ddac0d39SJens Axboe } 1114ddac0d39SJens Axboe 1115ddac0d39SJens Axboe /* 111683f9135bSJens Axboe * Determine where to splice to/from. 111783f9135bSJens Axboe */ 1118529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1119529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1120529565dcSIngo Molnar size_t len, unsigned int flags) 11215274f052SJens Axboe { 11223a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1123cbb7e577SJens Axboe loff_t offset, *off; 1124a4514ebdSJens Axboe long ret; 11255274f052SJens Axboe 11260f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1127529565dcSIngo Molnar if (pipe) { 1128529565dcSIngo Molnar if (off_in) 1129529565dcSIngo Molnar return -ESPIPE; 1130b92ce558SJens Axboe if (off_out) { 1131b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1132b92ce558SJens Axboe return -EINVAL; 1133cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1134b92ce558SJens Axboe return -EFAULT; 1135cbb7e577SJens Axboe off = &offset; 1136cbb7e577SJens Axboe } else 1137cbb7e577SJens Axboe off = &out->f_pos; 1138529565dcSIngo Molnar 1139a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1140a4514ebdSJens Axboe 1141a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1142a4514ebdSJens Axboe ret = -EFAULT; 1143a4514ebdSJens Axboe 1144a4514ebdSJens Axboe return ret; 1145529565dcSIngo Molnar } 11465274f052SJens Axboe 11470f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1148529565dcSIngo Molnar if (pipe) { 1149529565dcSIngo Molnar if (off_out) 1150529565dcSIngo Molnar return -ESPIPE; 1151b92ce558SJens Axboe if (off_in) { 1152b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1153b92ce558SJens Axboe return -EINVAL; 1154cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1155b92ce558SJens Axboe return -EFAULT; 1156cbb7e577SJens Axboe off = &offset; 1157cbb7e577SJens Axboe } else 1158cbb7e577SJens Axboe off = &in->f_pos; 1159529565dcSIngo Molnar 1160a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1161a4514ebdSJens Axboe 1162a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1163a4514ebdSJens Axboe ret = -EFAULT; 1164a4514ebdSJens Axboe 1165a4514ebdSJens Axboe return ret; 1166529565dcSIngo Molnar } 11675274f052SJens Axboe 11685274f052SJens Axboe return -EINVAL; 11695274f052SJens Axboe } 11705274f052SJens Axboe 1171912d35f8SJens Axboe /* 117275723957SLinus Torvalds * Do a copy-from-user while holding the mmap_semaphore for reading, in a 117375723957SLinus Torvalds * manner safe from deadlocking with simultaneous mmap() (grabbing mmap_sem 117475723957SLinus Torvalds * for writing) and page faulting on the user memory pointed to by src. 117575723957SLinus Torvalds * This assumes that we will very rarely hit the partial != 0 path, or this 117675723957SLinus Torvalds * will not be a win. 117775723957SLinus Torvalds */ 117875723957SLinus Torvalds static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n) 117975723957SLinus Torvalds { 118075723957SLinus Torvalds int partial; 118175723957SLinus Torvalds 11828811930dSJens Axboe if (!access_ok(VERIFY_READ, src, n)) 11838811930dSJens Axboe return -EFAULT; 11848811930dSJens Axboe 118575723957SLinus Torvalds pagefault_disable(); 118675723957SLinus Torvalds partial = __copy_from_user_inatomic(dst, src, n); 118775723957SLinus Torvalds pagefault_enable(); 118875723957SLinus Torvalds 118975723957SLinus Torvalds /* 119075723957SLinus Torvalds * Didn't copy everything, drop the mmap_sem and do a faulting copy 119175723957SLinus Torvalds */ 119275723957SLinus Torvalds if (unlikely(partial)) { 119375723957SLinus Torvalds up_read(¤t->mm->mmap_sem); 119475723957SLinus Torvalds partial = copy_from_user(dst, src, n); 119575723957SLinus Torvalds down_read(¤t->mm->mmap_sem); 119675723957SLinus Torvalds } 119775723957SLinus Torvalds 119875723957SLinus Torvalds return partial; 119975723957SLinus Torvalds } 120075723957SLinus Torvalds 120175723957SLinus Torvalds /* 1202912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1203912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1204912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1205912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1206912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1207912d35f8SJens Axboe */ 1208912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1209912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 12107afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1211912d35f8SJens Axboe { 1212912d35f8SJens Axboe int buffers = 0, error = 0; 1213912d35f8SJens Axboe 1214912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1215912d35f8SJens Axboe 1216912d35f8SJens Axboe while (nr_vecs) { 1217912d35f8SJens Axboe unsigned long off, npages; 121875723957SLinus Torvalds struct iovec entry; 1219912d35f8SJens Axboe void __user *base; 1220912d35f8SJens Axboe size_t len; 1221912d35f8SJens Axboe int i; 1222912d35f8SJens Axboe 122375723957SLinus Torvalds error = -EFAULT; 122475723957SLinus Torvalds if (copy_from_user_mmap_sem(&entry, iov, sizeof(entry))) 1225912d35f8SJens Axboe break; 122675723957SLinus Torvalds 122775723957SLinus Torvalds base = entry.iov_base; 122875723957SLinus Torvalds len = entry.iov_len; 1229912d35f8SJens Axboe 1230912d35f8SJens Axboe /* 1231912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1232912d35f8SJens Axboe */ 123375723957SLinus Torvalds error = 0; 1234912d35f8SJens Axboe if (unlikely(!len)) 1235912d35f8SJens Axboe break; 1236912d35f8SJens Axboe error = -EFAULT; 1237712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1238912d35f8SJens Axboe break; 1239912d35f8SJens Axboe 1240912d35f8SJens Axboe /* 1241912d35f8SJens Axboe * Get this base offset and number of pages, then map 1242912d35f8SJens Axboe * in the user pages. 1243912d35f8SJens Axboe */ 1244912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12457afa6fd0SJens Axboe 12467afa6fd0SJens Axboe /* 12477afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12487afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12497afa6fd0SJens Axboe */ 12507afa6fd0SJens Axboe error = -EINVAL; 12517afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12527afa6fd0SJens Axboe break; 12537afa6fd0SJens Axboe 1254912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1255912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1256912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1257912d35f8SJens Axboe 1258912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1259912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1260912d35f8SJens Axboe &pages[buffers], NULL); 1261912d35f8SJens Axboe 1262912d35f8SJens Axboe if (unlikely(error <= 0)) 1263912d35f8SJens Axboe break; 1264912d35f8SJens Axboe 1265912d35f8SJens Axboe /* 1266912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1267912d35f8SJens Axboe */ 1268912d35f8SJens Axboe for (i = 0; i < error; i++) { 12697591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1270912d35f8SJens Axboe 1271912d35f8SJens Axboe partial[buffers].offset = off; 1272912d35f8SJens Axboe partial[buffers].len = plen; 1273912d35f8SJens Axboe 1274912d35f8SJens Axboe off = 0; 1275912d35f8SJens Axboe len -= plen; 1276912d35f8SJens Axboe buffers++; 1277912d35f8SJens Axboe } 1278912d35f8SJens Axboe 1279912d35f8SJens Axboe /* 1280912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1281912d35f8SJens Axboe * means we have to move some of this into a pipe to 1282912d35f8SJens Axboe * be able to continue. 1283912d35f8SJens Axboe */ 1284912d35f8SJens Axboe if (len) 1285912d35f8SJens Axboe break; 1286912d35f8SJens Axboe 1287912d35f8SJens Axboe /* 1288912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1289912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1290912d35f8SJens Axboe * room for. 1291912d35f8SJens Axboe */ 1292912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1293912d35f8SJens Axboe break; 1294912d35f8SJens Axboe 1295912d35f8SJens Axboe nr_vecs--; 1296912d35f8SJens Axboe iov++; 1297912d35f8SJens Axboe } 1298912d35f8SJens Axboe 1299912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1300912d35f8SJens Axboe 1301912d35f8SJens Axboe if (buffers) 1302912d35f8SJens Axboe return buffers; 1303912d35f8SJens Axboe 1304912d35f8SJens Axboe return error; 1305912d35f8SJens Axboe } 1306912d35f8SJens Axboe 13076a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13086a14b90bSJens Axboe struct splice_desc *sd) 13096a14b90bSJens Axboe { 13106a14b90bSJens Axboe char *src; 13116a14b90bSJens Axboe int ret; 13126a14b90bSJens Axboe 1313cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 13146a14b90bSJens Axboe if (unlikely(ret)) 13156a14b90bSJens Axboe return ret; 13166a14b90bSJens Axboe 13176a14b90bSJens Axboe /* 13186a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13196a14b90bSJens Axboe * pages and doing an atomic copy 13206a14b90bSJens Axboe */ 13216a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13226a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13236a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13246a14b90bSJens Axboe sd->len); 13256a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13266a14b90bSJens Axboe if (!ret) { 13276a14b90bSJens Axboe ret = sd->len; 13286a14b90bSJens Axboe goto out; 13296a14b90bSJens Axboe } 13306a14b90bSJens Axboe } 13316a14b90bSJens Axboe 13326a14b90bSJens Axboe /* 13336a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13346a14b90bSJens Axboe */ 13356a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13366a14b90bSJens Axboe 13376a14b90bSJens Axboe ret = sd->len; 13386a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13396a14b90bSJens Axboe ret = -EFAULT; 13406a14b90bSJens Axboe 13416866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 13426a14b90bSJens Axboe out: 13436a14b90bSJens Axboe if (ret > 0) 13446a14b90bSJens Axboe sd->u.userptr += ret; 13456a14b90bSJens Axboe return ret; 13466a14b90bSJens Axboe } 13476a14b90bSJens Axboe 13486a14b90bSJens Axboe /* 13496a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13506a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13516a14b90bSJens Axboe */ 13526a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13536a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13546a14b90bSJens Axboe { 13556a14b90bSJens Axboe struct pipe_inode_info *pipe; 13566a14b90bSJens Axboe struct splice_desc sd; 13576a14b90bSJens Axboe ssize_t size; 13586a14b90bSJens Axboe int error; 13596a14b90bSJens Axboe long ret; 13606a14b90bSJens Axboe 13616a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13626a14b90bSJens Axboe if (!pipe) 13636a14b90bSJens Axboe return -EBADF; 13646a14b90bSJens Axboe 13656a14b90bSJens Axboe if (pipe->inode) 13666a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13676a14b90bSJens Axboe 13686a14b90bSJens Axboe error = ret = 0; 13696a14b90bSJens Axboe while (nr_segs) { 13706a14b90bSJens Axboe void __user *base; 13716a14b90bSJens Axboe size_t len; 13726a14b90bSJens Axboe 13736a14b90bSJens Axboe /* 13746a14b90bSJens Axboe * Get user address base and length for this iovec. 13756a14b90bSJens Axboe */ 13766a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13776a14b90bSJens Axboe if (unlikely(error)) 13786a14b90bSJens Axboe break; 13796a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13806a14b90bSJens Axboe if (unlikely(error)) 13816a14b90bSJens Axboe break; 13826a14b90bSJens Axboe 13836a14b90bSJens Axboe /* 13846a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13856a14b90bSJens Axboe */ 13866a14b90bSJens Axboe if (unlikely(!len)) 13876a14b90bSJens Axboe break; 13886a14b90bSJens Axboe if (unlikely(!base)) { 13896a14b90bSJens Axboe error = -EFAULT; 13906a14b90bSJens Axboe break; 13916a14b90bSJens Axboe } 13926a14b90bSJens Axboe 13938811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 13948811930dSJens Axboe error = -EFAULT; 13958811930dSJens Axboe break; 13968811930dSJens Axboe } 13978811930dSJens Axboe 13986a14b90bSJens Axboe sd.len = 0; 13996a14b90bSJens Axboe sd.total_len = len; 14006a14b90bSJens Axboe sd.flags = flags; 14016a14b90bSJens Axboe sd.u.userptr = base; 14026a14b90bSJens Axboe sd.pos = 0; 14036a14b90bSJens Axboe 14046a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 14056a14b90bSJens Axboe if (size < 0) { 14066a14b90bSJens Axboe if (!ret) 14076a14b90bSJens Axboe ret = size; 14086a14b90bSJens Axboe 14096a14b90bSJens Axboe break; 14106a14b90bSJens Axboe } 14116a14b90bSJens Axboe 14126a14b90bSJens Axboe ret += size; 14136a14b90bSJens Axboe 14146a14b90bSJens Axboe if (size < len) 14156a14b90bSJens Axboe break; 14166a14b90bSJens Axboe 14176a14b90bSJens Axboe nr_segs--; 14186a14b90bSJens Axboe iov++; 14196a14b90bSJens Axboe } 14206a14b90bSJens Axboe 14216a14b90bSJens Axboe if (pipe->inode) 14226a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14236a14b90bSJens Axboe 14246a14b90bSJens Axboe if (!ret) 14256a14b90bSJens Axboe ret = error; 14266a14b90bSJens Axboe 14276a14b90bSJens Axboe return ret; 14286a14b90bSJens Axboe } 14296a14b90bSJens Axboe 1430912d35f8SJens Axboe /* 1431912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1432912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1433912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1434912d35f8SJens Axboe */ 14356a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1436912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1437912d35f8SJens Axboe { 1438ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1439912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1440912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1441912d35f8SJens Axboe struct splice_pipe_desc spd = { 1442912d35f8SJens Axboe .pages = pages, 1443912d35f8SJens Axboe .partial = partial, 1444912d35f8SJens Axboe .flags = flags, 1445912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1446bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1447912d35f8SJens Axboe }; 1448912d35f8SJens Axboe 14490f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1450ddac0d39SJens Axboe if (!pipe) 1451912d35f8SJens Axboe return -EBADF; 1452912d35f8SJens Axboe 14537afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14547afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1455912d35f8SJens Axboe if (spd.nr_pages <= 0) 1456912d35f8SJens Axboe return spd.nr_pages; 1457912d35f8SJens Axboe 145800522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1459912d35f8SJens Axboe } 1460912d35f8SJens Axboe 14616a14b90bSJens Axboe /* 14626a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14636a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14646a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14656a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14666a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14676a14b90bSJens Axboe * solutions for that: 14686a14b90bSJens Axboe * 14696a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14706a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14716a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14726a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14736a14b90bSJens Axboe * 14746a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14756a14b90bSJens Axboe * 14766a14b90bSJens Axboe */ 1477912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1478912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1479912d35f8SJens Axboe { 1480912d35f8SJens Axboe struct file *file; 1481912d35f8SJens Axboe long error; 1482912d35f8SJens Axboe int fput; 1483912d35f8SJens Axboe 14846a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14856a14b90bSJens Axboe return -EINVAL; 14866a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14876a14b90bSJens Axboe return 0; 14886a14b90bSJens Axboe 1489912d35f8SJens Axboe error = -EBADF; 1490912d35f8SJens Axboe file = fget_light(fd, &fput); 1491912d35f8SJens Axboe if (file) { 1492912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14936a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14946a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14956a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1496912d35f8SJens Axboe 1497912d35f8SJens Axboe fput_light(file, fput); 1498912d35f8SJens Axboe } 1499912d35f8SJens Axboe 1500912d35f8SJens Axboe return error; 1501912d35f8SJens Axboe } 1502912d35f8SJens Axboe 1503529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1504529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1505529565dcSIngo Molnar size_t len, unsigned int flags) 15065274f052SJens Axboe { 15075274f052SJens Axboe long error; 15085274f052SJens Axboe struct file *in, *out; 15095274f052SJens Axboe int fput_in, fput_out; 15105274f052SJens Axboe 15115274f052SJens Axboe if (unlikely(!len)) 15125274f052SJens Axboe return 0; 15135274f052SJens Axboe 15145274f052SJens Axboe error = -EBADF; 1515529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 15165274f052SJens Axboe if (in) { 15175274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1518529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15195274f052SJens Axboe if (out) { 15205274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1521529565dcSIngo Molnar error = do_splice(in, off_in, 1522529565dcSIngo Molnar out, off_out, 1523529565dcSIngo Molnar len, flags); 15245274f052SJens Axboe fput_light(out, fput_out); 15255274f052SJens Axboe } 15265274f052SJens Axboe } 15275274f052SJens Axboe 15285274f052SJens Axboe fput_light(in, fput_in); 15295274f052SJens Axboe } 15305274f052SJens Axboe 15315274f052SJens Axboe return error; 15325274f052SJens Axboe } 153370524490SJens Axboe 153470524490SJens Axboe /* 1535aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1536aadd06e5SJens Axboe * return an appropriate error. 1537aadd06e5SJens Axboe */ 1538aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1539aadd06e5SJens Axboe { 1540aadd06e5SJens Axboe int ret; 1541aadd06e5SJens Axboe 1542aadd06e5SJens Axboe /* 1543aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1544aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1545aadd06e5SJens Axboe */ 1546aadd06e5SJens Axboe if (pipe->nrbufs) 1547aadd06e5SJens Axboe return 0; 1548aadd06e5SJens Axboe 1549aadd06e5SJens Axboe ret = 0; 1550aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1551aadd06e5SJens Axboe 1552aadd06e5SJens Axboe while (!pipe->nrbufs) { 1553aadd06e5SJens Axboe if (signal_pending(current)) { 1554aadd06e5SJens Axboe ret = -ERESTARTSYS; 1555aadd06e5SJens Axboe break; 1556aadd06e5SJens Axboe } 1557aadd06e5SJens Axboe if (!pipe->writers) 1558aadd06e5SJens Axboe break; 1559aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1560aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1561aadd06e5SJens Axboe ret = -EAGAIN; 1562aadd06e5SJens Axboe break; 1563aadd06e5SJens Axboe } 1564aadd06e5SJens Axboe } 1565aadd06e5SJens Axboe pipe_wait(pipe); 1566aadd06e5SJens Axboe } 1567aadd06e5SJens Axboe 1568aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1569aadd06e5SJens Axboe return ret; 1570aadd06e5SJens Axboe } 1571aadd06e5SJens Axboe 1572aadd06e5SJens Axboe /* 1573aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1574aadd06e5SJens Axboe * return an appropriate error. 1575aadd06e5SJens Axboe */ 1576aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1577aadd06e5SJens Axboe { 1578aadd06e5SJens Axboe int ret; 1579aadd06e5SJens Axboe 1580aadd06e5SJens Axboe /* 1581aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1582aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1583aadd06e5SJens Axboe */ 1584aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1585aadd06e5SJens Axboe return 0; 1586aadd06e5SJens Axboe 1587aadd06e5SJens Axboe ret = 0; 1588aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1589aadd06e5SJens Axboe 1590aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1591aadd06e5SJens Axboe if (!pipe->readers) { 1592aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1593aadd06e5SJens Axboe ret = -EPIPE; 1594aadd06e5SJens Axboe break; 1595aadd06e5SJens Axboe } 1596aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1597aadd06e5SJens Axboe ret = -EAGAIN; 1598aadd06e5SJens Axboe break; 1599aadd06e5SJens Axboe } 1600aadd06e5SJens Axboe if (signal_pending(current)) { 1601aadd06e5SJens Axboe ret = -ERESTARTSYS; 1602aadd06e5SJens Axboe break; 1603aadd06e5SJens Axboe } 1604aadd06e5SJens Axboe pipe->waiting_writers++; 1605aadd06e5SJens Axboe pipe_wait(pipe); 1606aadd06e5SJens Axboe pipe->waiting_writers--; 1607aadd06e5SJens Axboe } 1608aadd06e5SJens Axboe 1609aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1610aadd06e5SJens Axboe return ret; 1611aadd06e5SJens Axboe } 1612aadd06e5SJens Axboe 1613aadd06e5SJens Axboe /* 161470524490SJens Axboe * Link contents of ipipe to opipe. 161570524490SJens Axboe */ 161670524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 161770524490SJens Axboe struct pipe_inode_info *opipe, 161870524490SJens Axboe size_t len, unsigned int flags) 161970524490SJens Axboe { 162070524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1621aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 162270524490SJens Axboe 162370524490SJens Axboe /* 162470524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 162570524490SJens Axboe * grabbing by inode address. Otherwise two different processes 162670524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 162770524490SJens Axboe */ 162862752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 162970524490SJens Axboe 1630aadd06e5SJens Axboe do { 163170524490SJens Axboe if (!opipe->readers) { 163270524490SJens Axboe send_sig(SIGPIPE, current, 0); 163370524490SJens Axboe if (!ret) 163470524490SJens Axboe ret = -EPIPE; 163570524490SJens Axboe break; 163670524490SJens Axboe } 163770524490SJens Axboe 163870524490SJens Axboe /* 1639aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1640aadd06e5SJens Axboe * output room, break. 164170524490SJens Axboe */ 1642aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1643aadd06e5SJens Axboe break; 1644aadd06e5SJens Axboe 1645aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1646aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 164770524490SJens Axboe 164870524490SJens Axboe /* 164970524490SJens Axboe * Get a reference to this pipe buffer, 165070524490SJens Axboe * so we can copy the contents over. 165170524490SJens Axboe */ 165270524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 165370524490SJens Axboe 165470524490SJens Axboe obuf = opipe->bufs + nbuf; 165570524490SJens Axboe *obuf = *ibuf; 165670524490SJens Axboe 16577afa6fd0SJens Axboe /* 16587afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16597afa6fd0SJens Axboe * prevent multiple steals of this page. 16607afa6fd0SJens Axboe */ 16617afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16627afa6fd0SJens Axboe 166370524490SJens Axboe if (obuf->len > len) 166470524490SJens Axboe obuf->len = len; 166570524490SJens Axboe 166670524490SJens Axboe opipe->nrbufs++; 166770524490SJens Axboe ret += obuf->len; 166870524490SJens Axboe len -= obuf->len; 1669aadd06e5SJens Axboe i++; 1670aadd06e5SJens Axboe } while (len); 167170524490SJens Axboe 167202cf01aeSJens Axboe /* 167302cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 167402cf01aeSJens Axboe * future, otherwise just return 0 167502cf01aeSJens Axboe */ 167602cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 167702cf01aeSJens Axboe ret = -EAGAIN; 167802cf01aeSJens Axboe 167962752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 168070524490SJens Axboe 1681aadd06e5SJens Axboe /* 1682aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1683aadd06e5SJens Axboe */ 1684aadd06e5SJens Axboe if (ret > 0) { 168570524490SJens Axboe smp_mb(); 168670524490SJens Axboe if (waitqueue_active(&opipe->wait)) 168770524490SJens Axboe wake_up_interruptible(&opipe->wait); 168870524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 168970524490SJens Axboe } 169070524490SJens Axboe 169170524490SJens Axboe return ret; 169270524490SJens Axboe } 169370524490SJens Axboe 169470524490SJens Axboe /* 169570524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 169670524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 169770524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 169870524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 169970524490SJens Axboe */ 170070524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 170170524490SJens Axboe unsigned int flags) 170270524490SJens Axboe { 17030f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 17040f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1705aadd06e5SJens Axboe int ret = -EINVAL; 170670524490SJens Axboe 170770524490SJens Axboe /* 1708aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1709aadd06e5SJens Axboe * copying the data. 171070524490SJens Axboe */ 1711aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1712aadd06e5SJens Axboe /* 1713aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1714aadd06e5SJens Axboe * ordering doesn't really matter. 1715aadd06e5SJens Axboe */ 1716aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1717aadd06e5SJens Axboe if (!ret) { 1718aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 171902cf01aeSJens Axboe if (!ret) 1720aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1721aadd06e5SJens Axboe } 1722aadd06e5SJens Axboe } 172370524490SJens Axboe 1724aadd06e5SJens Axboe return ret; 172570524490SJens Axboe } 172670524490SJens Axboe 172770524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 172870524490SJens Axboe { 172970524490SJens Axboe struct file *in; 173070524490SJens Axboe int error, fput_in; 173170524490SJens Axboe 173270524490SJens Axboe if (unlikely(!len)) 173370524490SJens Axboe return 0; 173470524490SJens Axboe 173570524490SJens Axboe error = -EBADF; 173670524490SJens Axboe in = fget_light(fdin, &fput_in); 173770524490SJens Axboe if (in) { 173870524490SJens Axboe if (in->f_mode & FMODE_READ) { 173970524490SJens Axboe int fput_out; 174070524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 174170524490SJens Axboe 174270524490SJens Axboe if (out) { 174370524490SJens Axboe if (out->f_mode & FMODE_WRITE) 174470524490SJens Axboe error = do_tee(in, out, len, flags); 174570524490SJens Axboe fput_light(out, fput_out); 174670524490SJens Axboe } 174770524490SJens Axboe } 174870524490SJens Axboe fput_light(in, fput_in); 174970524490SJens Axboe } 175070524490SJens Axboe 175170524490SJens Axboe return error; 175270524490SJens Axboe } 1753