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 61ca39d651SJens Axboe if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) 62ca39d651SJens Axboe goto out_unlock; 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 */ 78ca39d651SJens Axboe out_unlock: 799e94cd4fSJens Axboe unlock_page(page); 809e94cd4fSJens Axboe return 1; 819e94cd4fSJens Axboe } 825abc97aaSJens Axboe 8376ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 845274f052SJens Axboe struct pipe_buffer *buf) 855274f052SJens Axboe { 865274f052SJens Axboe page_cache_release(buf->page); 871432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 885274f052SJens Axboe } 895274f052SJens Axboe 900845718dSJens Axboe /* 910845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 920845718dSJens Axboe * is a page cache page, IO may be in flight. 930845718dSJens Axboe */ 94cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 955274f052SJens Axboe struct pipe_buffer *buf) 965274f052SJens Axboe { 975274f052SJens Axboe struct page *page = buf->page; 9849d0b21bSJens Axboe int err; 995274f052SJens Axboe 1005274f052SJens Axboe if (!PageUptodate(page)) { 10149d0b21bSJens Axboe lock_page(page); 1025274f052SJens Axboe 10349d0b21bSJens Axboe /* 10449d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10573d62d83SIngo Molnar * splice, if this is the first page. 10649d0b21bSJens Axboe */ 1075274f052SJens Axboe if (!page->mapping) { 10849d0b21bSJens Axboe err = -ENODATA; 10949d0b21bSJens Axboe goto error; 1105274f052SJens Axboe } 1115274f052SJens Axboe 11249d0b21bSJens Axboe /* 11373d62d83SIngo Molnar * Uh oh, read-error from disk. 11449d0b21bSJens Axboe */ 11549d0b21bSJens Axboe if (!PageUptodate(page)) { 11649d0b21bSJens Axboe err = -EIO; 11749d0b21bSJens Axboe goto error; 11849d0b21bSJens Axboe } 11949d0b21bSJens Axboe 12049d0b21bSJens Axboe /* 121f84d7519SJens Axboe * Page is ok afterall, we are done. 12249d0b21bSJens Axboe */ 12349d0b21bSJens Axboe unlock_page(page); 12449d0b21bSJens Axboe } 12549d0b21bSJens Axboe 126f84d7519SJens Axboe return 0; 12749d0b21bSJens Axboe error: 12849d0b21bSJens Axboe unlock_page(page); 129f84d7519SJens Axboe return err; 13070524490SJens Axboe } 13170524490SJens Axboe 132d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1335274f052SJens Axboe .can_merge = 0, 134f84d7519SJens Axboe .map = generic_pipe_buf_map, 135f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 136cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1375274f052SJens Axboe .release = page_cache_pipe_buf_release, 1385abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 139f84d7519SJens Axboe .get = generic_pipe_buf_get, 1405274f052SJens Axboe }; 1415274f052SJens Axboe 142912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 143912d35f8SJens Axboe struct pipe_buffer *buf) 144912d35f8SJens Axboe { 1457afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 146912d35f8SJens Axboe return 1; 1477afa6fd0SJens Axboe 1481432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 149330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 150912d35f8SJens Axboe } 151912d35f8SJens Axboe 152d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 153912d35f8SJens Axboe .can_merge = 0, 154f84d7519SJens Axboe .map = generic_pipe_buf_map, 155f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 156cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 157912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 158912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 159f84d7519SJens Axboe .get = generic_pipe_buf_get, 160912d35f8SJens Axboe }; 161912d35f8SJens Axboe 162932cc6d4SJens Axboe /** 163932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 164932cc6d4SJens Axboe * @pipe: pipe to fill 165932cc6d4SJens Axboe * @spd: data to fill 166932cc6d4SJens Axboe * 167932cc6d4SJens Axboe * Description: 16879685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 169932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 170932cc6d4SJens Axboe * function will link that data to the pipe. 171932cc6d4SJens Axboe * 17283f9135bSJens Axboe */ 173d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 174912d35f8SJens Axboe struct splice_pipe_desc *spd) 1755274f052SJens Axboe { 17600de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 177912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1785274f052SJens Axboe 1795274f052SJens Axboe ret = 0; 1805274f052SJens Axboe do_wakeup = 0; 181912d35f8SJens Axboe page_nr = 0; 1825274f052SJens Axboe 1833a326a2cSIngo Molnar if (pipe->inode) 1843a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1855274f052SJens Axboe 1865274f052SJens Axboe for (;;) { 1873a326a2cSIngo Molnar if (!pipe->readers) { 1885274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1895274f052SJens Axboe if (!ret) 1905274f052SJens Axboe ret = -EPIPE; 1915274f052SJens Axboe break; 1925274f052SJens Axboe } 1935274f052SJens Axboe 1946f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1956f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1963a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1975274f052SJens Axboe 198912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 199912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 200912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 201497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 202912d35f8SJens Axboe buf->ops = spd->ops; 2037afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2047afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2057afa6fd0SJens Axboe 2066f767b04SJens Axboe pipe->nrbufs++; 207912d35f8SJens Axboe page_nr++; 208912d35f8SJens Axboe ret += buf->len; 209912d35f8SJens Axboe 2106f767b04SJens Axboe if (pipe->inode) 2115274f052SJens Axboe do_wakeup = 1; 2125274f052SJens Axboe 213912d35f8SJens Axboe if (!--spd->nr_pages) 2145274f052SJens Axboe break; 2156f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2165274f052SJens Axboe continue; 2175274f052SJens Axboe 2185274f052SJens Axboe break; 2195274f052SJens Axboe } 2205274f052SJens Axboe 221912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22229e35094SLinus Torvalds if (!ret) 22329e35094SLinus Torvalds ret = -EAGAIN; 22429e35094SLinus Torvalds break; 22529e35094SLinus Torvalds } 22629e35094SLinus Torvalds 2275274f052SJens Axboe if (signal_pending(current)) { 2285274f052SJens Axboe if (!ret) 2295274f052SJens Axboe ret = -ERESTARTSYS; 2305274f052SJens Axboe break; 2315274f052SJens Axboe } 2325274f052SJens Axboe 2335274f052SJens Axboe if (do_wakeup) { 234c0bd1f65SJens Axboe smp_mb(); 2353a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2363a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2373a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2385274f052SJens Axboe do_wakeup = 0; 2395274f052SJens Axboe } 2405274f052SJens Axboe 2413a326a2cSIngo Molnar pipe->waiting_writers++; 2423a326a2cSIngo Molnar pipe_wait(pipe); 2433a326a2cSIngo Molnar pipe->waiting_writers--; 2445274f052SJens Axboe } 2455274f052SJens Axboe 24602676e5aSJens Axboe if (pipe->inode) { 2473a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2485274f052SJens Axboe 2495274f052SJens Axboe if (do_wakeup) { 250c0bd1f65SJens Axboe smp_mb(); 2513a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2523a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2533a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2545274f052SJens Axboe } 25502676e5aSJens Axboe } 2565274f052SJens Axboe 25700de00bdSJens Axboe while (page_nr < spd_pages) 258bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2595274f052SJens Axboe 2605274f052SJens Axboe return ret; 2615274f052SJens Axboe } 2625274f052SJens Axboe 263bbdfc2f7SJens Axboe static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 264bbdfc2f7SJens Axboe { 265bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 266bbdfc2f7SJens Axboe } 267bbdfc2f7SJens Axboe 2683a326a2cSIngo Molnar static int 269cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 270cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 271cbb7e577SJens Axboe unsigned int flags) 2725274f052SJens Axboe { 2735274f052SJens Axboe struct address_space *mapping = in->f_mapping; 274d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 27516c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 276912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2775274f052SJens Axboe struct page *page; 27891ad66efSJens Axboe pgoff_t index, end_index; 27991ad66efSJens Axboe loff_t isize; 280eb20796bSJens Axboe int error, page_nr; 281912d35f8SJens Axboe struct splice_pipe_desc spd = { 282912d35f8SJens Axboe .pages = pages, 283912d35f8SJens Axboe .partial = partial, 284912d35f8SJens Axboe .flags = flags, 285912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 286bbdfc2f7SJens Axboe .spd_release = spd_release_page, 287912d35f8SJens Axboe }; 2885274f052SJens Axboe 289cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 290912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 291d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 292d8983910SFengguang Wu nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); 2935274f052SJens Axboe 2945274f052SJens Axboe /* 295eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29682aa5d61SJens Axboe */ 297eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 298431a4820SFengguang Wu index += spd.nr_pages; 299eb20796bSJens Axboe 3005274f052SJens Axboe /* 301eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 302431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 303eb20796bSJens Axboe */ 304431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 305cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 306cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 307431a4820SFengguang Wu 308932cc6d4SJens Axboe error = 0; 309eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 310eb20796bSJens Axboe /* 311eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 312eb20796bSJens Axboe * the first hole. 3135274f052SJens Axboe */ 3147480a904SJens Axboe page = find_get_page(mapping, index); 3157480a904SJens Axboe if (!page) { 316e27dedd8SJens Axboe /* 317eb20796bSJens Axboe * page didn't exist, allocate one. 3187480a904SJens Axboe */ 3197480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3205274f052SJens Axboe if (!page) 3215274f052SJens Axboe break; 3225274f052SJens Axboe 3237480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3244cd13504SHugh Dickins mapping_gfp_mask(mapping)); 3255274f052SJens Axboe if (unlikely(error)) { 3265274f052SJens Axboe page_cache_release(page); 327a0548871SJens Axboe if (error == -EEXIST) 328a0548871SJens Axboe continue; 3295274f052SJens Axboe break; 3305274f052SJens Axboe } 331eb20796bSJens Axboe /* 332eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 333eb20796bSJens Axboe * to avoid convoluting the logic below even more. 334eb20796bSJens Axboe */ 335eb20796bSJens Axboe unlock_page(page); 3365274f052SJens Axboe } 3377480a904SJens Axboe 338eb20796bSJens Axboe pages[spd.nr_pages++] = page; 339eb20796bSJens Axboe index++; 340eb20796bSJens Axboe } 341eb20796bSJens Axboe 342eb20796bSJens Axboe /* 343eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 344eb20796bSJens Axboe * pages, fill in the partial map, etc. 345eb20796bSJens Axboe */ 346eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 347eb20796bSJens Axboe nr_pages = spd.nr_pages; 348eb20796bSJens Axboe spd.nr_pages = 0; 349eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 350eb20796bSJens Axboe unsigned int this_len; 351eb20796bSJens Axboe 352eb20796bSJens Axboe if (!len) 353eb20796bSJens Axboe break; 354eb20796bSJens Axboe 355eb20796bSJens Axboe /* 356eb20796bSJens Axboe * this_len is the max we'll use from this page 357eb20796bSJens Axboe */ 358eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 359eb20796bSJens Axboe page = pages[page_nr]; 360eb20796bSJens Axboe 361a08a166fSFengguang Wu if (PageReadahead(page)) 362cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 363d8983910SFengguang Wu page, index, req_pages - page_nr); 364a08a166fSFengguang Wu 3657480a904SJens Axboe /* 3667480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3677480a904SJens Axboe */ 3687480a904SJens Axboe if (!PageUptodate(page)) { 369c4f895cbSJens Axboe /* 370c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 371c4f895cbSJens Axboe * for an in-flight io page 372c4f895cbSJens Axboe */ 3739ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3748191ecd1SJens Axboe if (TestSetPageLocked(page)) { 3758191ecd1SJens Axboe error = -EAGAIN; 376c4f895cbSJens Axboe break; 3778191ecd1SJens Axboe } 3789ae9d68cSFengguang Wu } else 3797480a904SJens Axboe lock_page(page); 3807480a904SJens Axboe 3817480a904SJens Axboe /* 3827480a904SJens Axboe * page was truncated, stop here. if this isn't the 3837480a904SJens Axboe * first page, we'll just complete what we already 3847480a904SJens Axboe * added 3857480a904SJens Axboe */ 3867480a904SJens Axboe if (!page->mapping) { 3877480a904SJens Axboe unlock_page(page); 3887480a904SJens Axboe break; 3897480a904SJens Axboe } 3907480a904SJens Axboe /* 3917480a904SJens Axboe * page was already under io and is now done, great 3927480a904SJens Axboe */ 3937480a904SJens Axboe if (PageUptodate(page)) { 3947480a904SJens Axboe unlock_page(page); 3957480a904SJens Axboe goto fill_it; 3967480a904SJens Axboe } 3977480a904SJens Axboe 3987480a904SJens Axboe /* 3997480a904SJens Axboe * need to read in the page 4007480a904SJens Axboe */ 4017480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4027480a904SJens Axboe if (unlikely(error)) { 403eb20796bSJens Axboe /* 404eb20796bSJens Axboe * We really should re-lookup the page here, 405eb20796bSJens Axboe * but it complicates things a lot. Instead 406eb20796bSJens Axboe * lets just do what we already stored, and 407eb20796bSJens Axboe * we'll get it the next time we are called. 408eb20796bSJens Axboe */ 4097480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 410eb20796bSJens Axboe error = 0; 411eb20796bSJens Axboe 4127480a904SJens Axboe break; 4137480a904SJens Axboe } 414620a324bSJens Axboe } 415620a324bSJens Axboe fill_it: 41691ad66efSJens Axboe /* 417620a324bSJens Axboe * i_size must be checked after PageUptodate. 41891ad66efSJens Axboe */ 41991ad66efSJens Axboe isize = i_size_read(mapping->host); 42091ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 421eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 42291ad66efSJens Axboe break; 42391ad66efSJens Axboe 42491ad66efSJens Axboe /* 42591ad66efSJens Axboe * if this is the last page, see if we need to shrink 42691ad66efSJens Axboe * the length and stop 42791ad66efSJens Axboe */ 42891ad66efSJens Axboe if (end_index == index) { 429475ecadeSHugh Dickins unsigned int plen; 430475ecadeSHugh Dickins 431475ecadeSHugh Dickins /* 432475ecadeSHugh Dickins * max good bytes in this page 433475ecadeSHugh Dickins */ 434475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 435475ecadeSHugh Dickins if (plen <= loff) 43691ad66efSJens Axboe break; 437475ecadeSHugh Dickins 43891ad66efSJens Axboe /* 43991ad66efSJens Axboe * force quit after adding this page 44091ad66efSJens Axboe */ 441475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 442eb20796bSJens Axboe len = this_len; 44391ad66efSJens Axboe } 444620a324bSJens Axboe 445eb20796bSJens Axboe partial[page_nr].offset = loff; 446eb20796bSJens Axboe partial[page_nr].len = this_len; 44782aa5d61SJens Axboe len -= this_len; 44891ad66efSJens Axboe loff = 0; 449eb20796bSJens Axboe spd.nr_pages++; 450eb20796bSJens Axboe index++; 4515274f052SJens Axboe } 4525274f052SJens Axboe 453eb20796bSJens Axboe /* 454475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 455eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 456eb20796bSJens Axboe */ 457eb20796bSJens Axboe while (page_nr < nr_pages) 458eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 459f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 460eb20796bSJens Axboe 461912d35f8SJens Axboe if (spd.nr_pages) 46200522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 46316c523ddSJens Axboe 4647480a904SJens Axboe return error; 4655274f052SJens Axboe } 4665274f052SJens Axboe 46783f9135bSJens Axboe /** 46883f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 46983f9135bSJens Axboe * @in: file to splice from 470932cc6d4SJens Axboe * @ppos: position in @in 47183f9135bSJens Axboe * @pipe: pipe to splice to 47283f9135bSJens Axboe * @len: number of bytes to splice 47383f9135bSJens Axboe * @flags: splice modifier flags 47483f9135bSJens Axboe * 475932cc6d4SJens Axboe * Description: 476932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 477932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 478932cc6d4SJens Axboe * a readpage() hook. 479932cc6d4SJens Axboe * 48083f9135bSJens Axboe */ 481cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 482cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 483cbb7e577SJens Axboe unsigned int flags) 4845274f052SJens Axboe { 485d366d398SJens Axboe loff_t isize, left; 4868191ecd1SJens Axboe int ret; 487d366d398SJens Axboe 488d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 489d366d398SJens Axboe if (unlikely(*ppos >= isize)) 490d366d398SJens Axboe return 0; 491d366d398SJens Axboe 492d366d398SJens Axboe left = isize - *ppos; 493d366d398SJens Axboe if (unlikely(left < len)) 494d366d398SJens Axboe len = left; 4955274f052SJens Axboe 496cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 4978191ecd1SJens Axboe if (ret > 0) 498cbb7e577SJens Axboe *ppos += ret; 4995274f052SJens Axboe 5005274f052SJens Axboe return ret; 5015274f052SJens Axboe } 5025274f052SJens Axboe 503059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 504059a8f37SJens Axboe 5055274f052SJens Axboe /* 5064f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 507016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5085274f052SJens Axboe */ 50976ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5105274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5115274f052SJens Axboe { 5126a14b90bSJens Axboe struct file *file = sd->u.file; 5135274f052SJens Axboe loff_t pos = sd->pos; 514f84d7519SJens Axboe int ret, more; 5155274f052SJens Axboe 516cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 517f84d7519SJens Axboe if (!ret) { 518b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5195274f052SJens Axboe 520f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 521f84d7519SJens Axboe sd->len, &pos, more); 522f84d7519SJens Axboe } 5235274f052SJens Axboe 524016b661eSJens Axboe return ret; 5255274f052SJens Axboe } 5265274f052SJens Axboe 5275274f052SJens Axboe /* 5285274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5295274f052SJens Axboe * basically three cases: 5305274f052SJens Axboe * 5315274f052SJens Axboe * - Destination page already exists in the address space and there 5325274f052SJens Axboe * are users of it. For that case we have no other option that 5335274f052SJens Axboe * copying the data. Tough luck. 5345274f052SJens Axboe * - Destination page already exists in the address space, but there 5355274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5365274f052SJens Axboe * through to last case. 5375274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5385274f052SJens Axboe * the page cache and avoid the copy. 5395274f052SJens Axboe * 54083f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 54183f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 54283f9135bSJens Axboe * file address space page cache. This is possible if no one else has 54383f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 54483f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 54583f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5465274f052SJens Axboe */ 54776ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5485274f052SJens Axboe struct splice_desc *sd) 5495274f052SJens Axboe { 5506a14b90bSJens Axboe struct file *file = sd->u.file; 5515274f052SJens Axboe struct address_space *mapping = file->f_mapping; 552016b661eSJens Axboe unsigned int offset, this_len; 5535274f052SJens Axboe struct page *page; 554afddba49SNick Piggin void *fsdata; 5553e7ee3e7SJens Axboe int ret; 5565274f052SJens Axboe 5575274f052SJens Axboe /* 55849d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5595274f052SJens Axboe */ 560cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 561f84d7519SJens Axboe if (unlikely(ret)) 562f84d7519SJens Axboe return ret; 5635274f052SJens Axboe 5645274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5655274f052SJens Axboe 566016b661eSJens Axboe this_len = sd->len; 567016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 568016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 569016b661eSJens Axboe 570afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 571afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 5729e0267c2SJens Axboe if (unlikely(ret)) 573afddba49SNick Piggin goto out; 5745274f052SJens Axboe 5750568b409SJens Axboe if (buf->page != page) { 576f84d7519SJens Axboe /* 577f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 578f84d7519SJens Axboe */ 57976ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 580f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 5815abc97aaSJens Axboe 582016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 5835274f052SJens Axboe flush_dcache_page(page); 584f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 58576ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 5865abc97aaSJens Axboe } 587afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 588afddba49SNick Piggin page, fsdata); 5890568b409SJens Axboe out: 5905274f052SJens Axboe return ret; 5915274f052SJens Axboe } 5925274f052SJens Axboe 593932cc6d4SJens Axboe /** 594932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 595932cc6d4SJens Axboe * @pipe: pipe to splice from 596932cc6d4SJens Axboe * @sd: information to @actor 597932cc6d4SJens Axboe * @actor: handler that splices the data 598932cc6d4SJens Axboe * 599932cc6d4SJens Axboe * Description: 600932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 601932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 602932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 603932cc6d4SJens Axboe * pipe_to_user. 604932cc6d4SJens Axboe * 60583f9135bSJens Axboe */ 606c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 607c66ab6faSJens Axboe splice_actor *actor) 6085274f052SJens Axboe { 6095274f052SJens Axboe int ret, do_wakeup, err; 6105274f052SJens Axboe 6115274f052SJens Axboe ret = 0; 6125274f052SJens Axboe do_wakeup = 0; 6135274f052SJens Axboe 6145274f052SJens Axboe for (;;) { 6156f767b04SJens Axboe if (pipe->nrbufs) { 6166f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 617d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6185274f052SJens Axboe 619c66ab6faSJens Axboe sd->len = buf->len; 620c66ab6faSJens Axboe if (sd->len > sd->total_len) 621c66ab6faSJens Axboe sd->len = sd->total_len; 6225274f052SJens Axboe 623c66ab6faSJens Axboe err = actor(pipe, buf, sd); 624016b661eSJens Axboe if (err <= 0) { 6255274f052SJens Axboe if (!ret && err != -ENODATA) 6265274f052SJens Axboe ret = err; 6275274f052SJens Axboe 6285274f052SJens Axboe break; 6295274f052SJens Axboe } 6305274f052SJens Axboe 631016b661eSJens Axboe ret += err; 632016b661eSJens Axboe buf->offset += err; 633016b661eSJens Axboe buf->len -= err; 634016b661eSJens Axboe 635c66ab6faSJens Axboe sd->len -= err; 636c66ab6faSJens Axboe sd->pos += err; 637c66ab6faSJens Axboe sd->total_len -= err; 638c66ab6faSJens Axboe if (sd->len) 639016b661eSJens Axboe continue; 64073d62d83SIngo Molnar 6415274f052SJens Axboe if (!buf->len) { 6425274f052SJens Axboe buf->ops = NULL; 6433a326a2cSIngo Molnar ops->release(pipe, buf); 6446f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 6456f767b04SJens Axboe pipe->nrbufs--; 6466f767b04SJens Axboe if (pipe->inode) 6475274f052SJens Axboe do_wakeup = 1; 6485274f052SJens Axboe } 6495274f052SJens Axboe 650c66ab6faSJens Axboe if (!sd->total_len) 6515274f052SJens Axboe break; 6525274f052SJens Axboe } 6535274f052SJens Axboe 6546f767b04SJens Axboe if (pipe->nrbufs) 6555274f052SJens Axboe continue; 6563a326a2cSIngo Molnar if (!pipe->writers) 6575274f052SJens Axboe break; 6583a326a2cSIngo Molnar if (!pipe->waiting_writers) { 6595274f052SJens Axboe if (ret) 6605274f052SJens Axboe break; 6615274f052SJens Axboe } 6625274f052SJens Axboe 663c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 66429e35094SLinus Torvalds if (!ret) 66529e35094SLinus Torvalds ret = -EAGAIN; 66629e35094SLinus Torvalds break; 66729e35094SLinus Torvalds } 66829e35094SLinus Torvalds 6695274f052SJens Axboe if (signal_pending(current)) { 6705274f052SJens Axboe if (!ret) 6715274f052SJens Axboe ret = -ERESTARTSYS; 6725274f052SJens Axboe break; 6735274f052SJens Axboe } 6745274f052SJens Axboe 6755274f052SJens Axboe if (do_wakeup) { 676c0bd1f65SJens Axboe smp_mb(); 6773a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6783a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 6793a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 6805274f052SJens Axboe do_wakeup = 0; 6815274f052SJens Axboe } 6825274f052SJens Axboe 6833a326a2cSIngo Molnar pipe_wait(pipe); 6845274f052SJens Axboe } 6855274f052SJens Axboe 6865274f052SJens Axboe if (do_wakeup) { 687c0bd1f65SJens Axboe smp_mb(); 6883a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6893a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 6903a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 6915274f052SJens Axboe } 6925274f052SJens Axboe 6935274f052SJens Axboe return ret; 6945274f052SJens Axboe } 69540bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6965274f052SJens Axboe 697932cc6d4SJens Axboe /** 698932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 699932cc6d4SJens Axboe * @pipe: pipe to splice from 700932cc6d4SJens Axboe * @out: file to splice to 701932cc6d4SJens Axboe * @ppos: position in @out 702932cc6d4SJens Axboe * @len: how many bytes to splice 703932cc6d4SJens Axboe * @flags: splice modifier flags 704932cc6d4SJens Axboe * @actor: handler that splices the data 705932cc6d4SJens Axboe * 706932cc6d4SJens Axboe * Description: 707932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 708932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 709932cc6d4SJens Axboe * 710932cc6d4SJens Axboe */ 7116da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7126da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7136da61809SMark Fasheh splice_actor *actor) 7146da61809SMark Fasheh { 7156da61809SMark Fasheh ssize_t ret; 7166da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 717c66ab6faSJens Axboe struct splice_desc sd = { 718c66ab6faSJens Axboe .total_len = len, 719c66ab6faSJens Axboe .flags = flags, 720c66ab6faSJens Axboe .pos = *ppos, 7216a14b90bSJens Axboe .u.file = out, 722c66ab6faSJens Axboe }; 7236da61809SMark Fasheh 7246da61809SMark Fasheh /* 7256da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7266da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7276da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7286da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7296da61809SMark Fasheh */ 7306da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 731c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7326da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7336da61809SMark Fasheh 7346da61809SMark Fasheh return ret; 7356da61809SMark Fasheh } 7366da61809SMark Fasheh 7376da61809SMark Fasheh /** 7386da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7396da61809SMark Fasheh * @pipe: pipe info 7406da61809SMark Fasheh * @out: file to write to 741932cc6d4SJens Axboe * @ppos: position in @out 7426da61809SMark Fasheh * @len: number of bytes to splice 7436da61809SMark Fasheh * @flags: splice modifier flags 7446da61809SMark Fasheh * 745932cc6d4SJens Axboe * Description: 7466da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7476da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7486da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7496da61809SMark Fasheh * 7506da61809SMark Fasheh */ 7516da61809SMark Fasheh ssize_t 7526da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 7536da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 7546da61809SMark Fasheh { 7556da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 7566da61809SMark Fasheh struct inode *inode = mapping->host; 757c66ab6faSJens Axboe struct splice_desc sd = { 758c66ab6faSJens Axboe .total_len = len, 759c66ab6faSJens Axboe .flags = flags, 760c66ab6faSJens Axboe .pos = *ppos, 7616a14b90bSJens Axboe .u.file = out, 762c66ab6faSJens Axboe }; 7636da61809SMark Fasheh ssize_t ret; 7646da61809SMark Fasheh int err; 7656da61809SMark Fasheh 7660f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 7678c34e2d6SJens Axboe if (unlikely(err)) 7688c34e2d6SJens Axboe return err; 7698c34e2d6SJens Axboe 770c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 7716da61809SMark Fasheh if (ret > 0) { 77217ee4f49SJens Axboe unsigned long nr_pages; 77317ee4f49SJens Axboe 7746da61809SMark Fasheh *ppos += ret; 77517ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 7766da61809SMark Fasheh 7776da61809SMark Fasheh /* 7786da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 7796da61809SMark Fasheh * sync it. 7806da61809SMark Fasheh */ 7816da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 7826da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 7836da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 7846da61809SMark Fasheh 7856da61809SMark Fasheh if (err) 7866da61809SMark Fasheh ret = err; 7876da61809SMark Fasheh } 78817ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 7896da61809SMark Fasheh } 7906da61809SMark Fasheh 7916da61809SMark Fasheh return ret; 7926da61809SMark Fasheh } 7936da61809SMark Fasheh 7946da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 7956da61809SMark Fasheh 79683f9135bSJens Axboe /** 79783f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 7983a326a2cSIngo Molnar * @pipe: pipe info 79983f9135bSJens Axboe * @out: file to write to 800932cc6d4SJens Axboe * @ppos: position in @out 80183f9135bSJens Axboe * @len: number of bytes to splice 80283f9135bSJens Axboe * @flags: splice modifier flags 80383f9135bSJens Axboe * 804932cc6d4SJens Axboe * Description: 80583f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 80683f9135bSJens Axboe * the given pipe inode to the given file. 80783f9135bSJens Axboe * 80883f9135bSJens Axboe */ 8093a326a2cSIngo Molnar ssize_t 8103a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 811cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8125274f052SJens Axboe { 8134f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8148c34e2d6SJens Axboe struct inode *inode = mapping->host; 8157f3d4ee1SMiklos Szeredi struct splice_desc sd = { 8167f3d4ee1SMiklos Szeredi .total_len = len, 8177f3d4ee1SMiklos Szeredi .flags = flags, 8187f3d4ee1SMiklos Szeredi .pos = *ppos, 8197f3d4ee1SMiklos Szeredi .u.file = out, 8207f3d4ee1SMiklos Szeredi }; 8213a326a2cSIngo Molnar ssize_t ret; 8228c34e2d6SJens Axboe 8237f3d4ee1SMiklos Szeredi inode_double_lock(inode, pipe->inode); 8247f3d4ee1SMiklos Szeredi ret = remove_suid(out->f_path.dentry); 8257f3d4ee1SMiklos Szeredi if (likely(!ret)) 8267f3d4ee1SMiklos Szeredi ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8277f3d4ee1SMiklos Szeredi inode_double_unlock(inode, pipe->inode); 828a4514ebdSJens Axboe if (ret > 0) { 82917ee4f49SJens Axboe unsigned long nr_pages; 83017ee4f49SJens Axboe 831a4514ebdSJens Axboe *ppos += ret; 83217ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8334f6f0bd2SJens Axboe 8344f6f0bd2SJens Axboe /* 835a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 836a4514ebdSJens Axboe * sync it. 8374f6f0bd2SJens Axboe */ 838a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8397f3d4ee1SMiklos Szeredi int err; 8407f3d4ee1SMiklos Szeredi 8414f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 842a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8434f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8444f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8454f6f0bd2SJens Axboe 8464f6f0bd2SJens Axboe if (err) 8474f6f0bd2SJens Axboe ret = err; 8484f6f0bd2SJens Axboe } 84917ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 850a4514ebdSJens Axboe } 8514f6f0bd2SJens Axboe 8524f6f0bd2SJens Axboe return ret; 8535274f052SJens Axboe } 8545274f052SJens Axboe 855059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 856059a8f37SJens Axboe 85783f9135bSJens Axboe /** 85883f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 859932cc6d4SJens Axboe * @pipe: pipe to splice from 86083f9135bSJens Axboe * @out: socket to write to 861932cc6d4SJens Axboe * @ppos: position in @out 86283f9135bSJens Axboe * @len: number of bytes to splice 86383f9135bSJens Axboe * @flags: splice modifier flags 86483f9135bSJens Axboe * 865932cc6d4SJens Axboe * Description: 86683f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 86783f9135bSJens Axboe * is involved. 86883f9135bSJens Axboe * 86983f9135bSJens Axboe */ 8703a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 871cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8725274f052SJens Axboe { 87300522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8745274f052SJens Axboe } 8755274f052SJens Axboe 876059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 877a0f06780SJeff Garzik 87883f9135bSJens Axboe /* 87983f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 88083f9135bSJens Axboe */ 8813a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 882cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8835274f052SJens Axboe { 8845274f052SJens Axboe int ret; 8855274f052SJens Axboe 88649570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 8875274f052SJens Axboe return -EINVAL; 8885274f052SJens Axboe 88949570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 8905274f052SJens Axboe return -EBADF; 8915274f052SJens Axboe 892cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 8935274f052SJens Axboe if (unlikely(ret < 0)) 8945274f052SJens Axboe return ret; 8955274f052SJens Axboe 896cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 8975274f052SJens Axboe } 8985274f052SJens Axboe 89983f9135bSJens Axboe /* 90083f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 90183f9135bSJens Axboe */ 902cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 903cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 904cbb7e577SJens Axboe unsigned int flags) 9055274f052SJens Axboe { 9065274f052SJens Axboe int ret; 9075274f052SJens Axboe 90849570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9095274f052SJens Axboe return -EINVAL; 9105274f052SJens Axboe 91149570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9125274f052SJens Axboe return -EBADF; 9135274f052SJens Axboe 914cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9155274f052SJens Axboe if (unlikely(ret < 0)) 9165274f052SJens Axboe return ret; 9175274f052SJens Axboe 918cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9195274f052SJens Axboe } 9205274f052SJens Axboe 921932cc6d4SJens Axboe /** 922932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 923932cc6d4SJens Axboe * @in: file to splice from 924932cc6d4SJens Axboe * @sd: actor information on where to splice to 925932cc6d4SJens Axboe * @actor: handles the data splicing 926932cc6d4SJens Axboe * 927932cc6d4SJens Axboe * Description: 928932cc6d4SJens Axboe * This is a special case helper to splice directly between two 929932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 930932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 931932cc6d4SJens Axboe * that process. 932932cc6d4SJens Axboe * 933c66ab6faSJens Axboe */ 934c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 935c66ab6faSJens Axboe splice_direct_actor *actor) 936b92ce558SJens Axboe { 937b92ce558SJens Axboe struct pipe_inode_info *pipe; 938b92ce558SJens Axboe long ret, bytes; 939b92ce558SJens Axboe umode_t i_mode; 940c66ab6faSJens Axboe size_t len; 941c66ab6faSJens Axboe int i, flags; 942b92ce558SJens Axboe 943b92ce558SJens Axboe /* 944b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 945b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 946b92ce558SJens Axboe * piped splicing for that! 947b92ce558SJens Axboe */ 9480f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 949b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 950b92ce558SJens Axboe return -EINVAL; 951b92ce558SJens Axboe 952b92ce558SJens Axboe /* 953b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 954b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 955b92ce558SJens Axboe */ 956b92ce558SJens Axboe pipe = current->splice_pipe; 95749570e9bSJens Axboe if (unlikely(!pipe)) { 958b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 959b92ce558SJens Axboe if (!pipe) 960b92ce558SJens Axboe return -ENOMEM; 961b92ce558SJens Axboe 962b92ce558SJens Axboe /* 963b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 96400522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 965b92ce558SJens Axboe * PIPE_READERS appropriately. 966b92ce558SJens Axboe */ 967b92ce558SJens Axboe pipe->readers = 1; 968b92ce558SJens Axboe 969b92ce558SJens Axboe current->splice_pipe = pipe; 970b92ce558SJens Axboe } 971b92ce558SJens Axboe 972b92ce558SJens Axboe /* 97373d62d83SIngo Molnar * Do the splice. 974b92ce558SJens Axboe */ 975b92ce558SJens Axboe ret = 0; 976b92ce558SJens Axboe bytes = 0; 977c66ab6faSJens Axboe len = sd->total_len; 978c66ab6faSJens Axboe flags = sd->flags; 979c66ab6faSJens Axboe 980c66ab6faSJens Axboe /* 981c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 982c66ab6faSJens Axboe */ 983c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 984b92ce558SJens Axboe 985b92ce558SJens Axboe while (len) { 98651a92c0fSJens Axboe size_t read_len; 987a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 988b92ce558SJens Axboe 989bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 99051a92c0fSJens Axboe if (unlikely(ret <= 0)) 991b92ce558SJens Axboe goto out_release; 992b92ce558SJens Axboe 993b92ce558SJens Axboe read_len = ret; 994c66ab6faSJens Axboe sd->total_len = read_len; 995b92ce558SJens Axboe 996b92ce558SJens Axboe /* 997b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 998b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 999b92ce558SJens Axboe * could get stuck data in the internal pipe: 1000b92ce558SJens Axboe */ 1001c66ab6faSJens Axboe ret = actor(pipe, sd); 1002a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1003a82c53a0STom Zanussi sd->pos = prev_pos; 1004b92ce558SJens Axboe goto out_release; 1005a82c53a0STom Zanussi } 1006b92ce558SJens Axboe 1007b92ce558SJens Axboe bytes += ret; 1008b92ce558SJens Axboe len -= ret; 1009bcd4f3acSJens Axboe sd->pos = pos; 1010b92ce558SJens Axboe 1011a82c53a0STom Zanussi if (ret < read_len) { 1012a82c53a0STom Zanussi sd->pos = prev_pos + ret; 101351a92c0fSJens Axboe goto out_release; 1014b92ce558SJens Axboe } 1015a82c53a0STom Zanussi } 1016b92ce558SJens Axboe 10179e97198dSJens Axboe done: 1018b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10199e97198dSJens Axboe file_accessed(in); 1020b92ce558SJens Axboe return bytes; 1021b92ce558SJens Axboe 1022b92ce558SJens Axboe out_release: 1023b92ce558SJens Axboe /* 1024b92ce558SJens Axboe * If we did an incomplete transfer we must release 1025b92ce558SJens Axboe * the pipe buffers in question: 1026b92ce558SJens Axboe */ 1027b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1028b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1029b92ce558SJens Axboe 1030b92ce558SJens Axboe if (buf->ops) { 1031b92ce558SJens Axboe buf->ops->release(pipe, buf); 1032b92ce558SJens Axboe buf->ops = NULL; 1033b92ce558SJens Axboe } 1034b92ce558SJens Axboe } 1035b92ce558SJens Axboe 10369e97198dSJens Axboe if (!bytes) 10379e97198dSJens Axboe bytes = ret; 1038b92ce558SJens Axboe 10399e97198dSJens Axboe goto done; 1040c66ab6faSJens Axboe } 1041c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1042c66ab6faSJens Axboe 1043c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1044c66ab6faSJens Axboe struct splice_desc *sd) 1045c66ab6faSJens Axboe { 10466a14b90bSJens Axboe struct file *file = sd->u.file; 1047c66ab6faSJens Axboe 1048c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1049c66ab6faSJens Axboe } 1050c66ab6faSJens Axboe 1051932cc6d4SJens Axboe /** 1052932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1053932cc6d4SJens Axboe * @in: file to splice from 1054932cc6d4SJens Axboe * @ppos: input file offset 1055932cc6d4SJens Axboe * @out: file to splice to 1056932cc6d4SJens Axboe * @len: number of bytes to splice 1057932cc6d4SJens Axboe * @flags: splice modifier flags 1058932cc6d4SJens Axboe * 1059932cc6d4SJens Axboe * Description: 1060932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1061932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1062932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1063932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1064932cc6d4SJens Axboe * 1065932cc6d4SJens Axboe */ 1066c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1067c66ab6faSJens Axboe size_t len, unsigned int flags) 1068c66ab6faSJens Axboe { 1069c66ab6faSJens Axboe struct splice_desc sd = { 1070c66ab6faSJens Axboe .len = len, 1071c66ab6faSJens Axboe .total_len = len, 1072c66ab6faSJens Axboe .flags = flags, 1073c66ab6faSJens Axboe .pos = *ppos, 10746a14b90bSJens Axboe .u.file = out, 1075c66ab6faSJens Axboe }; 107651a92c0fSJens Axboe long ret; 1077c66ab6faSJens Axboe 1078c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 107951a92c0fSJens Axboe if (ret > 0) 1080a82c53a0STom Zanussi *ppos = sd.pos; 108151a92c0fSJens Axboe 1082c66ab6faSJens Axboe return ret; 1083b92ce558SJens Axboe } 1084b92ce558SJens Axboe 108583f9135bSJens Axboe /* 1086ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1087ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1088ddac0d39SJens Axboe * pipe. 1089ddac0d39SJens Axboe */ 1090ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1091ddac0d39SJens Axboe { 1092ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1093ddac0d39SJens Axboe return inode->i_pipe; 1094ddac0d39SJens Axboe 1095ddac0d39SJens Axboe return NULL; 1096ddac0d39SJens Axboe } 1097ddac0d39SJens Axboe 1098ddac0d39SJens Axboe /* 109983f9135bSJens Axboe * Determine where to splice to/from. 110083f9135bSJens Axboe */ 1101529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1102529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1103529565dcSIngo Molnar size_t len, unsigned int flags) 11045274f052SJens Axboe { 11053a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1106cbb7e577SJens Axboe loff_t offset, *off; 1107a4514ebdSJens Axboe long ret; 11085274f052SJens Axboe 11090f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1110529565dcSIngo Molnar if (pipe) { 1111529565dcSIngo Molnar if (off_in) 1112529565dcSIngo Molnar return -ESPIPE; 1113b92ce558SJens Axboe if (off_out) { 1114b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1115b92ce558SJens Axboe return -EINVAL; 1116cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1117b92ce558SJens Axboe return -EFAULT; 1118cbb7e577SJens Axboe off = &offset; 1119cbb7e577SJens Axboe } else 1120cbb7e577SJens Axboe off = &out->f_pos; 1121529565dcSIngo Molnar 1122a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1123a4514ebdSJens Axboe 1124a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1125a4514ebdSJens Axboe ret = -EFAULT; 1126a4514ebdSJens Axboe 1127a4514ebdSJens Axboe return ret; 1128529565dcSIngo Molnar } 11295274f052SJens Axboe 11300f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1131529565dcSIngo Molnar if (pipe) { 1132529565dcSIngo Molnar if (off_out) 1133529565dcSIngo Molnar return -ESPIPE; 1134b92ce558SJens Axboe if (off_in) { 1135b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1136b92ce558SJens Axboe return -EINVAL; 1137cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1138b92ce558SJens Axboe return -EFAULT; 1139cbb7e577SJens Axboe off = &offset; 1140cbb7e577SJens Axboe } else 1141cbb7e577SJens Axboe off = &in->f_pos; 1142529565dcSIngo Molnar 1143a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1144a4514ebdSJens Axboe 1145a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1146a4514ebdSJens Axboe ret = -EFAULT; 1147a4514ebdSJens Axboe 1148a4514ebdSJens Axboe return ret; 1149529565dcSIngo Molnar } 11505274f052SJens Axboe 11515274f052SJens Axboe return -EINVAL; 11525274f052SJens Axboe } 11535274f052SJens Axboe 1154912d35f8SJens Axboe /* 115575723957SLinus Torvalds * Do a copy-from-user while holding the mmap_semaphore for reading, in a 115675723957SLinus Torvalds * manner safe from deadlocking with simultaneous mmap() (grabbing mmap_sem 115775723957SLinus Torvalds * for writing) and page faulting on the user memory pointed to by src. 115875723957SLinus Torvalds * This assumes that we will very rarely hit the partial != 0 path, or this 115975723957SLinus Torvalds * will not be a win. 116075723957SLinus Torvalds */ 116175723957SLinus Torvalds static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n) 116275723957SLinus Torvalds { 116375723957SLinus Torvalds int partial; 116475723957SLinus Torvalds 11658811930dSJens Axboe if (!access_ok(VERIFY_READ, src, n)) 11668811930dSJens Axboe return -EFAULT; 11678811930dSJens Axboe 116875723957SLinus Torvalds pagefault_disable(); 116975723957SLinus Torvalds partial = __copy_from_user_inatomic(dst, src, n); 117075723957SLinus Torvalds pagefault_enable(); 117175723957SLinus Torvalds 117275723957SLinus Torvalds /* 117375723957SLinus Torvalds * Didn't copy everything, drop the mmap_sem and do a faulting copy 117475723957SLinus Torvalds */ 117575723957SLinus Torvalds if (unlikely(partial)) { 117675723957SLinus Torvalds up_read(¤t->mm->mmap_sem); 117775723957SLinus Torvalds partial = copy_from_user(dst, src, n); 117875723957SLinus Torvalds down_read(¤t->mm->mmap_sem); 117975723957SLinus Torvalds } 118075723957SLinus Torvalds 118175723957SLinus Torvalds return partial; 118275723957SLinus Torvalds } 118375723957SLinus Torvalds 118475723957SLinus Torvalds /* 1185912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1186912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1187912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1188912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1189912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1190912d35f8SJens Axboe */ 1191912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1192912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 11937afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1194912d35f8SJens Axboe { 1195912d35f8SJens Axboe int buffers = 0, error = 0; 1196912d35f8SJens Axboe 1197912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1198912d35f8SJens Axboe 1199912d35f8SJens Axboe while (nr_vecs) { 1200912d35f8SJens Axboe unsigned long off, npages; 120175723957SLinus Torvalds struct iovec entry; 1202912d35f8SJens Axboe void __user *base; 1203912d35f8SJens Axboe size_t len; 1204912d35f8SJens Axboe int i; 1205912d35f8SJens Axboe 120675723957SLinus Torvalds error = -EFAULT; 120775723957SLinus Torvalds if (copy_from_user_mmap_sem(&entry, iov, sizeof(entry))) 1208912d35f8SJens Axboe break; 120975723957SLinus Torvalds 121075723957SLinus Torvalds base = entry.iov_base; 121175723957SLinus Torvalds len = entry.iov_len; 1212912d35f8SJens Axboe 1213912d35f8SJens Axboe /* 1214912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1215912d35f8SJens Axboe */ 121675723957SLinus Torvalds error = 0; 1217912d35f8SJens Axboe if (unlikely(!len)) 1218912d35f8SJens Axboe break; 1219912d35f8SJens Axboe error = -EFAULT; 1220712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1221912d35f8SJens Axboe break; 1222912d35f8SJens Axboe 1223912d35f8SJens Axboe /* 1224912d35f8SJens Axboe * Get this base offset and number of pages, then map 1225912d35f8SJens Axboe * in the user pages. 1226912d35f8SJens Axboe */ 1227912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12287afa6fd0SJens Axboe 12297afa6fd0SJens Axboe /* 12307afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12317afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12327afa6fd0SJens Axboe */ 12337afa6fd0SJens Axboe error = -EINVAL; 12347afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12357afa6fd0SJens Axboe break; 12367afa6fd0SJens Axboe 1237912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1238912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1239912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1240912d35f8SJens Axboe 1241912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1242912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1243912d35f8SJens Axboe &pages[buffers], NULL); 1244912d35f8SJens Axboe 1245912d35f8SJens Axboe if (unlikely(error <= 0)) 1246912d35f8SJens Axboe break; 1247912d35f8SJens Axboe 1248912d35f8SJens Axboe /* 1249912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1250912d35f8SJens Axboe */ 1251912d35f8SJens Axboe for (i = 0; i < error; i++) { 12527591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1253912d35f8SJens Axboe 1254912d35f8SJens Axboe partial[buffers].offset = off; 1255912d35f8SJens Axboe partial[buffers].len = plen; 1256912d35f8SJens Axboe 1257912d35f8SJens Axboe off = 0; 1258912d35f8SJens Axboe len -= plen; 1259912d35f8SJens Axboe buffers++; 1260912d35f8SJens Axboe } 1261912d35f8SJens Axboe 1262912d35f8SJens Axboe /* 1263912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1264912d35f8SJens Axboe * means we have to move some of this into a pipe to 1265912d35f8SJens Axboe * be able to continue. 1266912d35f8SJens Axboe */ 1267912d35f8SJens Axboe if (len) 1268912d35f8SJens Axboe break; 1269912d35f8SJens Axboe 1270912d35f8SJens Axboe /* 1271912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1272912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1273912d35f8SJens Axboe * room for. 1274912d35f8SJens Axboe */ 1275912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1276912d35f8SJens Axboe break; 1277912d35f8SJens Axboe 1278912d35f8SJens Axboe nr_vecs--; 1279912d35f8SJens Axboe iov++; 1280912d35f8SJens Axboe } 1281912d35f8SJens Axboe 1282912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1283912d35f8SJens Axboe 1284912d35f8SJens Axboe if (buffers) 1285912d35f8SJens Axboe return buffers; 1286912d35f8SJens Axboe 1287912d35f8SJens Axboe return error; 1288912d35f8SJens Axboe } 1289912d35f8SJens Axboe 12906a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12916a14b90bSJens Axboe struct splice_desc *sd) 12926a14b90bSJens Axboe { 12936a14b90bSJens Axboe char *src; 12946a14b90bSJens Axboe int ret; 12956a14b90bSJens Axboe 1296cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 12976a14b90bSJens Axboe if (unlikely(ret)) 12986a14b90bSJens Axboe return ret; 12996a14b90bSJens Axboe 13006a14b90bSJens Axboe /* 13016a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13026a14b90bSJens Axboe * pages and doing an atomic copy 13036a14b90bSJens Axboe */ 13046a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13056a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13066a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13076a14b90bSJens Axboe sd->len); 13086a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13096a14b90bSJens Axboe if (!ret) { 13106a14b90bSJens Axboe ret = sd->len; 13116a14b90bSJens Axboe goto out; 13126a14b90bSJens Axboe } 13136a14b90bSJens Axboe } 13146a14b90bSJens Axboe 13156a14b90bSJens Axboe /* 13166a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13176a14b90bSJens Axboe */ 13186a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13196a14b90bSJens Axboe 13206a14b90bSJens Axboe ret = sd->len; 13216a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13226a14b90bSJens Axboe ret = -EFAULT; 13236a14b90bSJens Axboe 13246866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 13256a14b90bSJens Axboe out: 13266a14b90bSJens Axboe if (ret > 0) 13276a14b90bSJens Axboe sd->u.userptr += ret; 13286a14b90bSJens Axboe return ret; 13296a14b90bSJens Axboe } 13306a14b90bSJens Axboe 13316a14b90bSJens Axboe /* 13326a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13336a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13346a14b90bSJens Axboe */ 13356a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13366a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13376a14b90bSJens Axboe { 13386a14b90bSJens Axboe struct pipe_inode_info *pipe; 13396a14b90bSJens Axboe struct splice_desc sd; 13406a14b90bSJens Axboe ssize_t size; 13416a14b90bSJens Axboe int error; 13426a14b90bSJens Axboe long ret; 13436a14b90bSJens Axboe 13446a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13456a14b90bSJens Axboe if (!pipe) 13466a14b90bSJens Axboe return -EBADF; 13476a14b90bSJens Axboe 13486a14b90bSJens Axboe if (pipe->inode) 13496a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13506a14b90bSJens Axboe 13516a14b90bSJens Axboe error = ret = 0; 13526a14b90bSJens Axboe while (nr_segs) { 13536a14b90bSJens Axboe void __user *base; 13546a14b90bSJens Axboe size_t len; 13556a14b90bSJens Axboe 13566a14b90bSJens Axboe /* 13576a14b90bSJens Axboe * Get user address base and length for this iovec. 13586a14b90bSJens Axboe */ 13596a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13606a14b90bSJens Axboe if (unlikely(error)) 13616a14b90bSJens Axboe break; 13626a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13636a14b90bSJens Axboe if (unlikely(error)) 13646a14b90bSJens Axboe break; 13656a14b90bSJens Axboe 13666a14b90bSJens Axboe /* 13676a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13686a14b90bSJens Axboe */ 13696a14b90bSJens Axboe if (unlikely(!len)) 13706a14b90bSJens Axboe break; 13716a14b90bSJens Axboe if (unlikely(!base)) { 13726a14b90bSJens Axboe error = -EFAULT; 13736a14b90bSJens Axboe break; 13746a14b90bSJens Axboe } 13756a14b90bSJens Axboe 13768811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 13778811930dSJens Axboe error = -EFAULT; 13788811930dSJens Axboe break; 13798811930dSJens Axboe } 13808811930dSJens Axboe 13816a14b90bSJens Axboe sd.len = 0; 13826a14b90bSJens Axboe sd.total_len = len; 13836a14b90bSJens Axboe sd.flags = flags; 13846a14b90bSJens Axboe sd.u.userptr = base; 13856a14b90bSJens Axboe sd.pos = 0; 13866a14b90bSJens Axboe 13876a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 13886a14b90bSJens Axboe if (size < 0) { 13896a14b90bSJens Axboe if (!ret) 13906a14b90bSJens Axboe ret = size; 13916a14b90bSJens Axboe 13926a14b90bSJens Axboe break; 13936a14b90bSJens Axboe } 13946a14b90bSJens Axboe 13956a14b90bSJens Axboe ret += size; 13966a14b90bSJens Axboe 13976a14b90bSJens Axboe if (size < len) 13986a14b90bSJens Axboe break; 13996a14b90bSJens Axboe 14006a14b90bSJens Axboe nr_segs--; 14016a14b90bSJens Axboe iov++; 14026a14b90bSJens Axboe } 14036a14b90bSJens Axboe 14046a14b90bSJens Axboe if (pipe->inode) 14056a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14066a14b90bSJens Axboe 14076a14b90bSJens Axboe if (!ret) 14086a14b90bSJens Axboe ret = error; 14096a14b90bSJens Axboe 14106a14b90bSJens Axboe return ret; 14116a14b90bSJens Axboe } 14126a14b90bSJens Axboe 1413912d35f8SJens Axboe /* 1414912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1415912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1416912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1417912d35f8SJens Axboe */ 14186a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1419912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1420912d35f8SJens Axboe { 1421ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1422912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1423912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1424912d35f8SJens Axboe struct splice_pipe_desc spd = { 1425912d35f8SJens Axboe .pages = pages, 1426912d35f8SJens Axboe .partial = partial, 1427912d35f8SJens Axboe .flags = flags, 1428912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1429bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1430912d35f8SJens Axboe }; 1431912d35f8SJens Axboe 14320f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1433ddac0d39SJens Axboe if (!pipe) 1434912d35f8SJens Axboe return -EBADF; 1435912d35f8SJens Axboe 14367afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14377afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1438912d35f8SJens Axboe if (spd.nr_pages <= 0) 1439912d35f8SJens Axboe return spd.nr_pages; 1440912d35f8SJens Axboe 144100522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1442912d35f8SJens Axboe } 1443912d35f8SJens Axboe 14446a14b90bSJens Axboe /* 14456a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14466a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14476a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14486a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14496a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14506a14b90bSJens Axboe * solutions for that: 14516a14b90bSJens Axboe * 14526a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14536a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14546a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14556a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14566a14b90bSJens Axboe * 14576a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14586a14b90bSJens Axboe * 14596a14b90bSJens Axboe */ 1460912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1461912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1462912d35f8SJens Axboe { 1463912d35f8SJens Axboe struct file *file; 1464912d35f8SJens Axboe long error; 1465912d35f8SJens Axboe int fput; 1466912d35f8SJens Axboe 14676a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14686a14b90bSJens Axboe return -EINVAL; 14696a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14706a14b90bSJens Axboe return 0; 14716a14b90bSJens Axboe 1472912d35f8SJens Axboe error = -EBADF; 1473912d35f8SJens Axboe file = fget_light(fd, &fput); 1474912d35f8SJens Axboe if (file) { 1475912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14766a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14776a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14786a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1479912d35f8SJens Axboe 1480912d35f8SJens Axboe fput_light(file, fput); 1481912d35f8SJens Axboe } 1482912d35f8SJens Axboe 1483912d35f8SJens Axboe return error; 1484912d35f8SJens Axboe } 1485912d35f8SJens Axboe 1486529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1487529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1488529565dcSIngo Molnar size_t len, unsigned int flags) 14895274f052SJens Axboe { 14905274f052SJens Axboe long error; 14915274f052SJens Axboe struct file *in, *out; 14925274f052SJens Axboe int fput_in, fput_out; 14935274f052SJens Axboe 14945274f052SJens Axboe if (unlikely(!len)) 14955274f052SJens Axboe return 0; 14965274f052SJens Axboe 14975274f052SJens Axboe error = -EBADF; 1498529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 14995274f052SJens Axboe if (in) { 15005274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1501529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15025274f052SJens Axboe if (out) { 15035274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1504529565dcSIngo Molnar error = do_splice(in, off_in, 1505529565dcSIngo Molnar out, off_out, 1506529565dcSIngo Molnar len, flags); 15075274f052SJens Axboe fput_light(out, fput_out); 15085274f052SJens Axboe } 15095274f052SJens Axboe } 15105274f052SJens Axboe 15115274f052SJens Axboe fput_light(in, fput_in); 15125274f052SJens Axboe } 15135274f052SJens Axboe 15145274f052SJens Axboe return error; 15155274f052SJens Axboe } 151670524490SJens Axboe 151770524490SJens Axboe /* 1518aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1519aadd06e5SJens Axboe * return an appropriate error. 1520aadd06e5SJens Axboe */ 1521aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1522aadd06e5SJens Axboe { 1523aadd06e5SJens Axboe int ret; 1524aadd06e5SJens Axboe 1525aadd06e5SJens Axboe /* 1526aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1527aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1528aadd06e5SJens Axboe */ 1529aadd06e5SJens Axboe if (pipe->nrbufs) 1530aadd06e5SJens Axboe return 0; 1531aadd06e5SJens Axboe 1532aadd06e5SJens Axboe ret = 0; 1533aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1534aadd06e5SJens Axboe 1535aadd06e5SJens Axboe while (!pipe->nrbufs) { 1536aadd06e5SJens Axboe if (signal_pending(current)) { 1537aadd06e5SJens Axboe ret = -ERESTARTSYS; 1538aadd06e5SJens Axboe break; 1539aadd06e5SJens Axboe } 1540aadd06e5SJens Axboe if (!pipe->writers) 1541aadd06e5SJens Axboe break; 1542aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1543aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1544aadd06e5SJens Axboe ret = -EAGAIN; 1545aadd06e5SJens Axboe break; 1546aadd06e5SJens Axboe } 1547aadd06e5SJens Axboe } 1548aadd06e5SJens Axboe pipe_wait(pipe); 1549aadd06e5SJens Axboe } 1550aadd06e5SJens Axboe 1551aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1552aadd06e5SJens Axboe return ret; 1553aadd06e5SJens Axboe } 1554aadd06e5SJens Axboe 1555aadd06e5SJens Axboe /* 1556aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1557aadd06e5SJens Axboe * return an appropriate error. 1558aadd06e5SJens Axboe */ 1559aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1560aadd06e5SJens Axboe { 1561aadd06e5SJens Axboe int ret; 1562aadd06e5SJens Axboe 1563aadd06e5SJens Axboe /* 1564aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1565aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1566aadd06e5SJens Axboe */ 1567aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1568aadd06e5SJens Axboe return 0; 1569aadd06e5SJens Axboe 1570aadd06e5SJens Axboe ret = 0; 1571aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1572aadd06e5SJens Axboe 1573aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1574aadd06e5SJens Axboe if (!pipe->readers) { 1575aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1576aadd06e5SJens Axboe ret = -EPIPE; 1577aadd06e5SJens Axboe break; 1578aadd06e5SJens Axboe } 1579aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1580aadd06e5SJens Axboe ret = -EAGAIN; 1581aadd06e5SJens Axboe break; 1582aadd06e5SJens Axboe } 1583aadd06e5SJens Axboe if (signal_pending(current)) { 1584aadd06e5SJens Axboe ret = -ERESTARTSYS; 1585aadd06e5SJens Axboe break; 1586aadd06e5SJens Axboe } 1587aadd06e5SJens Axboe pipe->waiting_writers++; 1588aadd06e5SJens Axboe pipe_wait(pipe); 1589aadd06e5SJens Axboe pipe->waiting_writers--; 1590aadd06e5SJens Axboe } 1591aadd06e5SJens Axboe 1592aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1593aadd06e5SJens Axboe return ret; 1594aadd06e5SJens Axboe } 1595aadd06e5SJens Axboe 1596aadd06e5SJens Axboe /* 159770524490SJens Axboe * Link contents of ipipe to opipe. 159870524490SJens Axboe */ 159970524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 160070524490SJens Axboe struct pipe_inode_info *opipe, 160170524490SJens Axboe size_t len, unsigned int flags) 160270524490SJens Axboe { 160370524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1604aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 160570524490SJens Axboe 160670524490SJens Axboe /* 160770524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 160870524490SJens Axboe * grabbing by inode address. Otherwise two different processes 160970524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 161070524490SJens Axboe */ 161162752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 161270524490SJens Axboe 1613aadd06e5SJens Axboe do { 161470524490SJens Axboe if (!opipe->readers) { 161570524490SJens Axboe send_sig(SIGPIPE, current, 0); 161670524490SJens Axboe if (!ret) 161770524490SJens Axboe ret = -EPIPE; 161870524490SJens Axboe break; 161970524490SJens Axboe } 162070524490SJens Axboe 162170524490SJens Axboe /* 1622aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1623aadd06e5SJens Axboe * output room, break. 162470524490SJens Axboe */ 1625aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1626aadd06e5SJens Axboe break; 1627aadd06e5SJens Axboe 1628aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1629aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 163070524490SJens Axboe 163170524490SJens Axboe /* 163270524490SJens Axboe * Get a reference to this pipe buffer, 163370524490SJens Axboe * so we can copy the contents over. 163470524490SJens Axboe */ 163570524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 163670524490SJens Axboe 163770524490SJens Axboe obuf = opipe->bufs + nbuf; 163870524490SJens Axboe *obuf = *ibuf; 163970524490SJens Axboe 16407afa6fd0SJens Axboe /* 16417afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16427afa6fd0SJens Axboe * prevent multiple steals of this page. 16437afa6fd0SJens Axboe */ 16447afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16457afa6fd0SJens Axboe 164670524490SJens Axboe if (obuf->len > len) 164770524490SJens Axboe obuf->len = len; 164870524490SJens Axboe 164970524490SJens Axboe opipe->nrbufs++; 165070524490SJens Axboe ret += obuf->len; 165170524490SJens Axboe len -= obuf->len; 1652aadd06e5SJens Axboe i++; 1653aadd06e5SJens Axboe } while (len); 165470524490SJens Axboe 165502cf01aeSJens Axboe /* 165602cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 165702cf01aeSJens Axboe * future, otherwise just return 0 165802cf01aeSJens Axboe */ 165902cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 166002cf01aeSJens Axboe ret = -EAGAIN; 166102cf01aeSJens Axboe 166262752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 166370524490SJens Axboe 1664aadd06e5SJens Axboe /* 1665aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1666aadd06e5SJens Axboe */ 1667aadd06e5SJens Axboe if (ret > 0) { 166870524490SJens Axboe smp_mb(); 166970524490SJens Axboe if (waitqueue_active(&opipe->wait)) 167070524490SJens Axboe wake_up_interruptible(&opipe->wait); 167170524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 167270524490SJens Axboe } 167370524490SJens Axboe 167470524490SJens Axboe return ret; 167570524490SJens Axboe } 167670524490SJens Axboe 167770524490SJens Axboe /* 167870524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 167970524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 168070524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 168170524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 168270524490SJens Axboe */ 168370524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 168470524490SJens Axboe unsigned int flags) 168570524490SJens Axboe { 16860f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 16870f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1688aadd06e5SJens Axboe int ret = -EINVAL; 168970524490SJens Axboe 169070524490SJens Axboe /* 1691aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1692aadd06e5SJens Axboe * copying the data. 169370524490SJens Axboe */ 1694aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1695aadd06e5SJens Axboe /* 1696aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1697aadd06e5SJens Axboe * ordering doesn't really matter. 1698aadd06e5SJens Axboe */ 1699aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1700aadd06e5SJens Axboe if (!ret) { 1701aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 170202cf01aeSJens Axboe if (!ret) 1703aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1704aadd06e5SJens Axboe } 1705aadd06e5SJens Axboe } 170670524490SJens Axboe 1707aadd06e5SJens Axboe return ret; 170870524490SJens Axboe } 170970524490SJens Axboe 171070524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 171170524490SJens Axboe { 171270524490SJens Axboe struct file *in; 171370524490SJens Axboe int error, fput_in; 171470524490SJens Axboe 171570524490SJens Axboe if (unlikely(!len)) 171670524490SJens Axboe return 0; 171770524490SJens Axboe 171870524490SJens Axboe error = -EBADF; 171970524490SJens Axboe in = fget_light(fdin, &fput_in); 172070524490SJens Axboe if (in) { 172170524490SJens Axboe if (in->f_mode & FMODE_READ) { 172270524490SJens Axboe int fput_out; 172370524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 172470524490SJens Axboe 172570524490SJens Axboe if (out) { 172670524490SJens Axboe if (out->f_mode & FMODE_WRITE) 172770524490SJens Axboe error = do_tee(in, out, len, flags); 172870524490SJens Axboe fput_light(out, fput_out); 172970524490SJens Axboe } 173070524490SJens Axboe } 173170524490SJens Axboe fput_light(in, fput_in); 173270524490SJens Axboe } 173370524490SJens Axboe 173470524490SJens Axboe return error; 173570524490SJens Axboe } 1736