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) { 374529ae9aaSNick Piggin if (!trylock_page(page)) { 3758191ecd1SJens Axboe error = -EAGAIN; 376c4f895cbSJens Axboe break; 3778191ecd1SJens Axboe } 3789ae9d68cSFengguang Wu } else 3797480a904SJens Axboe lock_page(page); 3807480a904SJens Axboe 3817480a904SJens Axboe /* 38232502b84SMiklos Szeredi * Page was truncated, or invalidated by the 38332502b84SMiklos Szeredi * filesystem. Redo the find/create, but this time the 38432502b84SMiklos Szeredi * page is kept locked, so there's no chance of another 38532502b84SMiklos Szeredi * race with truncate/invalidate. 3867480a904SJens Axboe */ 3877480a904SJens Axboe if (!page->mapping) { 3887480a904SJens Axboe unlock_page(page); 38932502b84SMiklos Szeredi page = find_or_create_page(mapping, index, 39032502b84SMiklos Szeredi mapping_gfp_mask(mapping)); 39132502b84SMiklos Szeredi 39232502b84SMiklos Szeredi if (!page) { 39332502b84SMiklos Szeredi error = -ENOMEM; 3947480a904SJens Axboe break; 3957480a904SJens Axboe } 39632502b84SMiklos Szeredi page_cache_release(pages[page_nr]); 39732502b84SMiklos Szeredi pages[page_nr] = page; 39832502b84SMiklos Szeredi } 3997480a904SJens Axboe /* 4007480a904SJens Axboe * page was already under io and is now done, great 4017480a904SJens Axboe */ 4027480a904SJens Axboe if (PageUptodate(page)) { 4037480a904SJens Axboe unlock_page(page); 4047480a904SJens Axboe goto fill_it; 4057480a904SJens Axboe } 4067480a904SJens Axboe 4077480a904SJens Axboe /* 4087480a904SJens Axboe * need to read in the page 4097480a904SJens Axboe */ 4107480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4117480a904SJens Axboe if (unlikely(error)) { 412eb20796bSJens Axboe /* 413eb20796bSJens Axboe * We really should re-lookup the page here, 414eb20796bSJens Axboe * but it complicates things a lot. Instead 415eb20796bSJens Axboe * lets just do what we already stored, and 416eb20796bSJens Axboe * we'll get it the next time we are called. 417eb20796bSJens Axboe */ 4187480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 419eb20796bSJens Axboe error = 0; 420eb20796bSJens Axboe 4217480a904SJens Axboe break; 4227480a904SJens Axboe } 423620a324bSJens Axboe } 424620a324bSJens Axboe fill_it: 42591ad66efSJens Axboe /* 426620a324bSJens Axboe * i_size must be checked after PageUptodate. 42791ad66efSJens Axboe */ 42891ad66efSJens Axboe isize = i_size_read(mapping->host); 42991ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 430eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 43191ad66efSJens Axboe break; 43291ad66efSJens Axboe 43391ad66efSJens Axboe /* 43491ad66efSJens Axboe * if this is the last page, see if we need to shrink 43591ad66efSJens Axboe * the length and stop 43691ad66efSJens Axboe */ 43791ad66efSJens Axboe if (end_index == index) { 438475ecadeSHugh Dickins unsigned int plen; 439475ecadeSHugh Dickins 440475ecadeSHugh Dickins /* 441475ecadeSHugh Dickins * max good bytes in this page 442475ecadeSHugh Dickins */ 443475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 444475ecadeSHugh Dickins if (plen <= loff) 44591ad66efSJens Axboe break; 446475ecadeSHugh Dickins 44791ad66efSJens Axboe /* 44891ad66efSJens Axboe * force quit after adding this page 44991ad66efSJens Axboe */ 450475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 451eb20796bSJens Axboe len = this_len; 45291ad66efSJens Axboe } 453620a324bSJens Axboe 454eb20796bSJens Axboe partial[page_nr].offset = loff; 455eb20796bSJens Axboe partial[page_nr].len = this_len; 45682aa5d61SJens Axboe len -= this_len; 45791ad66efSJens Axboe loff = 0; 458eb20796bSJens Axboe spd.nr_pages++; 459eb20796bSJens Axboe index++; 4605274f052SJens Axboe } 4615274f052SJens Axboe 462eb20796bSJens Axboe /* 463475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 464eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 465eb20796bSJens Axboe */ 466eb20796bSJens Axboe while (page_nr < nr_pages) 467eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 468f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 469eb20796bSJens Axboe 470912d35f8SJens Axboe if (spd.nr_pages) 47100522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 47216c523ddSJens Axboe 4737480a904SJens Axboe return error; 4745274f052SJens Axboe } 4755274f052SJens Axboe 47683f9135bSJens Axboe /** 47783f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 47883f9135bSJens Axboe * @in: file to splice from 479932cc6d4SJens Axboe * @ppos: position in @in 48083f9135bSJens Axboe * @pipe: pipe to splice to 48183f9135bSJens Axboe * @len: number of bytes to splice 48283f9135bSJens Axboe * @flags: splice modifier flags 48383f9135bSJens Axboe * 484932cc6d4SJens Axboe * Description: 485932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 486932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 487932cc6d4SJens Axboe * a readpage() hook. 488932cc6d4SJens Axboe * 48983f9135bSJens Axboe */ 490cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 491cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 492cbb7e577SJens Axboe unsigned int flags) 4935274f052SJens Axboe { 494d366d398SJens Axboe loff_t isize, left; 4958191ecd1SJens Axboe int ret; 496d366d398SJens Axboe 497d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 498d366d398SJens Axboe if (unlikely(*ppos >= isize)) 499d366d398SJens Axboe return 0; 500d366d398SJens Axboe 501d366d398SJens Axboe left = isize - *ppos; 502d366d398SJens Axboe if (unlikely(left < len)) 503d366d398SJens Axboe len = left; 5045274f052SJens Axboe 505cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 5068191ecd1SJens Axboe if (ret > 0) 507cbb7e577SJens Axboe *ppos += ret; 5085274f052SJens Axboe 5095274f052SJens Axboe return ret; 5105274f052SJens Axboe } 5115274f052SJens Axboe 512059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 513059a8f37SJens Axboe 5145274f052SJens Axboe /* 5154f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 516016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5175274f052SJens Axboe */ 51876ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5195274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5205274f052SJens Axboe { 5216a14b90bSJens Axboe struct file *file = sd->u.file; 5225274f052SJens Axboe loff_t pos = sd->pos; 523f84d7519SJens Axboe int ret, more; 5245274f052SJens Axboe 525cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 526f84d7519SJens Axboe if (!ret) { 527b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5285274f052SJens Axboe 529f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 530f84d7519SJens Axboe sd->len, &pos, more); 531f84d7519SJens Axboe } 5325274f052SJens Axboe 533016b661eSJens Axboe return ret; 5345274f052SJens Axboe } 5355274f052SJens Axboe 5365274f052SJens Axboe /* 5375274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5385274f052SJens Axboe * basically three cases: 5395274f052SJens Axboe * 5405274f052SJens Axboe * - Destination page already exists in the address space and there 5415274f052SJens Axboe * are users of it. For that case we have no other option that 5425274f052SJens Axboe * copying the data. Tough luck. 5435274f052SJens Axboe * - Destination page already exists in the address space, but there 5445274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5455274f052SJens Axboe * through to last case. 5465274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5475274f052SJens Axboe * the page cache and avoid the copy. 5485274f052SJens Axboe * 54983f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55083f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 55183f9135bSJens Axboe * file address space page cache. This is possible if no one else has 55283f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 55383f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 55483f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5555274f052SJens Axboe */ 55676ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5575274f052SJens Axboe struct splice_desc *sd) 5585274f052SJens Axboe { 5596a14b90bSJens Axboe struct file *file = sd->u.file; 5605274f052SJens Axboe struct address_space *mapping = file->f_mapping; 561016b661eSJens Axboe unsigned int offset, this_len; 5625274f052SJens Axboe struct page *page; 563afddba49SNick Piggin void *fsdata; 5643e7ee3e7SJens Axboe int ret; 5655274f052SJens Axboe 5665274f052SJens Axboe /* 56749d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5685274f052SJens Axboe */ 569cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 570f84d7519SJens Axboe if (unlikely(ret)) 571f84d7519SJens Axboe return ret; 5725274f052SJens Axboe 5735274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5745274f052SJens Axboe 575016b661eSJens Axboe this_len = sd->len; 576016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 577016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 578016b661eSJens Axboe 579afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 580afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 5819e0267c2SJens Axboe if (unlikely(ret)) 582afddba49SNick Piggin goto out; 5835274f052SJens Axboe 5840568b409SJens Axboe if (buf->page != page) { 585f84d7519SJens Axboe /* 586f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 587f84d7519SJens Axboe */ 58876ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 589f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 5905abc97aaSJens Axboe 591016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 5925274f052SJens Axboe flush_dcache_page(page); 593f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 59476ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 5955abc97aaSJens Axboe } 596afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 597afddba49SNick Piggin page, fsdata); 5980568b409SJens Axboe out: 5995274f052SJens Axboe return ret; 6005274f052SJens Axboe } 6015274f052SJens Axboe 602932cc6d4SJens Axboe /** 603932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 604932cc6d4SJens Axboe * @pipe: pipe to splice from 605932cc6d4SJens Axboe * @sd: information to @actor 606932cc6d4SJens Axboe * @actor: handler that splices the data 607932cc6d4SJens Axboe * 608932cc6d4SJens Axboe * Description: 609932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 610932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 611932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 612932cc6d4SJens Axboe * pipe_to_user. 613932cc6d4SJens Axboe * 61483f9135bSJens Axboe */ 615c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 616c66ab6faSJens Axboe splice_actor *actor) 6175274f052SJens Axboe { 6185274f052SJens Axboe int ret, do_wakeup, err; 6195274f052SJens Axboe 6205274f052SJens Axboe ret = 0; 6215274f052SJens Axboe do_wakeup = 0; 6225274f052SJens Axboe 6235274f052SJens Axboe for (;;) { 6246f767b04SJens Axboe if (pipe->nrbufs) { 6256f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 626d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6275274f052SJens Axboe 628c66ab6faSJens Axboe sd->len = buf->len; 629c66ab6faSJens Axboe if (sd->len > sd->total_len) 630c66ab6faSJens Axboe sd->len = sd->total_len; 6315274f052SJens Axboe 632c66ab6faSJens Axboe err = actor(pipe, buf, sd); 633016b661eSJens Axboe if (err <= 0) { 6345274f052SJens Axboe if (!ret && err != -ENODATA) 6355274f052SJens Axboe ret = err; 6365274f052SJens Axboe 6375274f052SJens Axboe break; 6385274f052SJens Axboe } 6395274f052SJens Axboe 640016b661eSJens Axboe ret += err; 641016b661eSJens Axboe buf->offset += err; 642016b661eSJens Axboe buf->len -= err; 643016b661eSJens Axboe 644c66ab6faSJens Axboe sd->len -= err; 645c66ab6faSJens Axboe sd->pos += err; 646c66ab6faSJens Axboe sd->total_len -= err; 647c66ab6faSJens Axboe if (sd->len) 648016b661eSJens Axboe continue; 64973d62d83SIngo Molnar 6505274f052SJens Axboe if (!buf->len) { 6515274f052SJens Axboe buf->ops = NULL; 6523a326a2cSIngo Molnar ops->release(pipe, buf); 6536f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 6546f767b04SJens Axboe pipe->nrbufs--; 6556f767b04SJens Axboe if (pipe->inode) 6565274f052SJens Axboe do_wakeup = 1; 6575274f052SJens Axboe } 6585274f052SJens Axboe 659c66ab6faSJens Axboe if (!sd->total_len) 6605274f052SJens Axboe break; 6615274f052SJens Axboe } 6625274f052SJens Axboe 6636f767b04SJens Axboe if (pipe->nrbufs) 6645274f052SJens Axboe continue; 6653a326a2cSIngo Molnar if (!pipe->writers) 6665274f052SJens Axboe break; 6673a326a2cSIngo Molnar if (!pipe->waiting_writers) { 6685274f052SJens Axboe if (ret) 6695274f052SJens Axboe break; 6705274f052SJens Axboe } 6715274f052SJens Axboe 672c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 67329e35094SLinus Torvalds if (!ret) 67429e35094SLinus Torvalds ret = -EAGAIN; 67529e35094SLinus Torvalds break; 67629e35094SLinus Torvalds } 67729e35094SLinus Torvalds 6785274f052SJens Axboe if (signal_pending(current)) { 6795274f052SJens Axboe if (!ret) 6805274f052SJens Axboe ret = -ERESTARTSYS; 6815274f052SJens Axboe break; 6825274f052SJens Axboe } 6835274f052SJens Axboe 6845274f052SJens Axboe if (do_wakeup) { 685c0bd1f65SJens Axboe smp_mb(); 6863a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6873a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 6883a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 6895274f052SJens Axboe do_wakeup = 0; 6905274f052SJens Axboe } 6915274f052SJens Axboe 6923a326a2cSIngo Molnar pipe_wait(pipe); 6935274f052SJens Axboe } 6945274f052SJens Axboe 6955274f052SJens Axboe if (do_wakeup) { 696c0bd1f65SJens Axboe smp_mb(); 6973a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6983a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 6993a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7005274f052SJens Axboe } 7015274f052SJens Axboe 7025274f052SJens Axboe return ret; 7035274f052SJens Axboe } 70440bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7055274f052SJens Axboe 706932cc6d4SJens Axboe /** 707932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 708932cc6d4SJens Axboe * @pipe: pipe to splice from 709932cc6d4SJens Axboe * @out: file to splice to 710932cc6d4SJens Axboe * @ppos: position in @out 711932cc6d4SJens Axboe * @len: how many bytes to splice 712932cc6d4SJens Axboe * @flags: splice modifier flags 713932cc6d4SJens Axboe * @actor: handler that splices the data 714932cc6d4SJens Axboe * 715932cc6d4SJens Axboe * Description: 716932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 717932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 718932cc6d4SJens Axboe * 719932cc6d4SJens Axboe */ 7206da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7216da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7226da61809SMark Fasheh splice_actor *actor) 7236da61809SMark Fasheh { 7246da61809SMark Fasheh ssize_t ret; 7256da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 726c66ab6faSJens Axboe struct splice_desc sd = { 727c66ab6faSJens Axboe .total_len = len, 728c66ab6faSJens Axboe .flags = flags, 729c66ab6faSJens Axboe .pos = *ppos, 7306a14b90bSJens Axboe .u.file = out, 731c66ab6faSJens Axboe }; 7326da61809SMark Fasheh 7336da61809SMark Fasheh /* 7346da61809SMark Fasheh * The actor worker might be calling ->prepare_write and 7356da61809SMark Fasheh * ->commit_write. Most of the time, these expect i_mutex to 7366da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7376da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7386da61809SMark Fasheh */ 7396da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 740c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7416da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7426da61809SMark Fasheh 7436da61809SMark Fasheh return ret; 7446da61809SMark Fasheh } 7456da61809SMark Fasheh 7466da61809SMark Fasheh /** 7476da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7486da61809SMark Fasheh * @pipe: pipe info 7496da61809SMark Fasheh * @out: file to write to 750932cc6d4SJens Axboe * @ppos: position in @out 7516da61809SMark Fasheh * @len: number of bytes to splice 7526da61809SMark Fasheh * @flags: splice modifier flags 7536da61809SMark Fasheh * 754932cc6d4SJens Axboe * Description: 7556da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7566da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7576da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7586da61809SMark Fasheh * 7596da61809SMark Fasheh */ 7606da61809SMark Fasheh ssize_t 7616da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 7626da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 7636da61809SMark Fasheh { 7646da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 7656da61809SMark Fasheh struct inode *inode = mapping->host; 766c66ab6faSJens Axboe struct splice_desc sd = { 767c66ab6faSJens Axboe .total_len = len, 768c66ab6faSJens Axboe .flags = flags, 769c66ab6faSJens Axboe .pos = *ppos, 7706a14b90bSJens Axboe .u.file = out, 771c66ab6faSJens Axboe }; 7726da61809SMark Fasheh ssize_t ret; 7736da61809SMark Fasheh int err; 7746da61809SMark Fasheh 7752f1936b8SMiklos Szeredi err = file_remove_suid(out); 7768c34e2d6SJens Axboe if (unlikely(err)) 7778c34e2d6SJens Axboe return err; 7788c34e2d6SJens Axboe 779c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 7806da61809SMark Fasheh if (ret > 0) { 78117ee4f49SJens Axboe unsigned long nr_pages; 78217ee4f49SJens Axboe 7836da61809SMark Fasheh *ppos += ret; 78417ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 7856da61809SMark Fasheh 7866da61809SMark Fasheh /* 7876da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 7886da61809SMark Fasheh * sync it. 7896da61809SMark Fasheh */ 7906da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 7916da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 7926da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 7936da61809SMark Fasheh 7946da61809SMark Fasheh if (err) 7956da61809SMark Fasheh ret = err; 7966da61809SMark Fasheh } 79717ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 7986da61809SMark Fasheh } 7996da61809SMark Fasheh 8006da61809SMark Fasheh return ret; 8016da61809SMark Fasheh } 8026da61809SMark Fasheh 8036da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8046da61809SMark Fasheh 80583f9135bSJens Axboe /** 80683f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8073a326a2cSIngo Molnar * @pipe: pipe info 80883f9135bSJens Axboe * @out: file to write to 809932cc6d4SJens Axboe * @ppos: position in @out 81083f9135bSJens Axboe * @len: number of bytes to splice 81183f9135bSJens Axboe * @flags: splice modifier flags 81283f9135bSJens Axboe * 813932cc6d4SJens Axboe * Description: 81483f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 81583f9135bSJens Axboe * the given pipe inode to the given file. 81683f9135bSJens Axboe * 81783f9135bSJens Axboe */ 8183a326a2cSIngo Molnar ssize_t 8193a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 820cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8215274f052SJens Axboe { 8224f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8238c34e2d6SJens Axboe struct inode *inode = mapping->host; 8247f3d4ee1SMiklos Szeredi struct splice_desc sd = { 8257f3d4ee1SMiklos Szeredi .total_len = len, 8267f3d4ee1SMiklos Szeredi .flags = flags, 8277f3d4ee1SMiklos Szeredi .pos = *ppos, 8287f3d4ee1SMiklos Szeredi .u.file = out, 8297f3d4ee1SMiklos Szeredi }; 8303a326a2cSIngo Molnar ssize_t ret; 8318c34e2d6SJens Axboe 8327f3d4ee1SMiklos Szeredi inode_double_lock(inode, pipe->inode); 8332f1936b8SMiklos Szeredi ret = file_remove_suid(out); 8347f3d4ee1SMiklos Szeredi if (likely(!ret)) 8357f3d4ee1SMiklos Szeredi ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8367f3d4ee1SMiklos Szeredi inode_double_unlock(inode, pipe->inode); 837a4514ebdSJens Axboe if (ret > 0) { 83817ee4f49SJens Axboe unsigned long nr_pages; 83917ee4f49SJens Axboe 840a4514ebdSJens Axboe *ppos += ret; 84117ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8424f6f0bd2SJens Axboe 8434f6f0bd2SJens Axboe /* 844a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 845a4514ebdSJens Axboe * sync it. 8464f6f0bd2SJens Axboe */ 847a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8487f3d4ee1SMiklos Szeredi int err; 8497f3d4ee1SMiklos Szeredi 8504f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 851a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8524f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8534f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8544f6f0bd2SJens Axboe 8554f6f0bd2SJens Axboe if (err) 8564f6f0bd2SJens Axboe ret = err; 8574f6f0bd2SJens Axboe } 85817ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 859a4514ebdSJens Axboe } 8604f6f0bd2SJens Axboe 8614f6f0bd2SJens Axboe return ret; 8625274f052SJens Axboe } 8635274f052SJens Axboe 864059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 865059a8f37SJens Axboe 86683f9135bSJens Axboe /** 86783f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 868932cc6d4SJens Axboe * @pipe: pipe to splice from 86983f9135bSJens Axboe * @out: socket to write to 870932cc6d4SJens Axboe * @ppos: position in @out 87183f9135bSJens Axboe * @len: number of bytes to splice 87283f9135bSJens Axboe * @flags: splice modifier flags 87383f9135bSJens Axboe * 874932cc6d4SJens Axboe * Description: 87583f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 87683f9135bSJens Axboe * is involved. 87783f9135bSJens Axboe * 87883f9135bSJens Axboe */ 8793a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 880cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8815274f052SJens Axboe { 88200522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8835274f052SJens Axboe } 8845274f052SJens Axboe 885059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 886a0f06780SJeff Garzik 88783f9135bSJens Axboe /* 88883f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 88983f9135bSJens Axboe */ 8903a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 891cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8925274f052SJens Axboe { 8935274f052SJens Axboe int ret; 8945274f052SJens Axboe 89549570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 8965274f052SJens Axboe return -EINVAL; 8975274f052SJens Axboe 89849570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 8995274f052SJens Axboe return -EBADF; 9005274f052SJens Axboe 901efc968d4SLinus Torvalds if (unlikely(out->f_flags & O_APPEND)) 902efc968d4SLinus Torvalds return -EINVAL; 903efc968d4SLinus Torvalds 904cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9055274f052SJens Axboe if (unlikely(ret < 0)) 9065274f052SJens Axboe return ret; 9075274f052SJens Axboe 908cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9095274f052SJens Axboe } 9105274f052SJens Axboe 91183f9135bSJens Axboe /* 91283f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 91383f9135bSJens Axboe */ 914cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 915cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 916cbb7e577SJens Axboe unsigned int flags) 9175274f052SJens Axboe { 9185274f052SJens Axboe int ret; 9195274f052SJens Axboe 92049570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9215274f052SJens Axboe return -EINVAL; 9225274f052SJens Axboe 92349570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9245274f052SJens Axboe return -EBADF; 9255274f052SJens Axboe 926cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9275274f052SJens Axboe if (unlikely(ret < 0)) 9285274f052SJens Axboe return ret; 9295274f052SJens Axboe 930cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9315274f052SJens Axboe } 9325274f052SJens Axboe 933932cc6d4SJens Axboe /** 934932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 935932cc6d4SJens Axboe * @in: file to splice from 936932cc6d4SJens Axboe * @sd: actor information on where to splice to 937932cc6d4SJens Axboe * @actor: handles the data splicing 938932cc6d4SJens Axboe * 939932cc6d4SJens Axboe * Description: 940932cc6d4SJens Axboe * This is a special case helper to splice directly between two 941932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 942932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 943932cc6d4SJens Axboe * that process. 944932cc6d4SJens Axboe * 945c66ab6faSJens Axboe */ 946c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 947c66ab6faSJens Axboe splice_direct_actor *actor) 948b92ce558SJens Axboe { 949b92ce558SJens Axboe struct pipe_inode_info *pipe; 950b92ce558SJens Axboe long ret, bytes; 951b92ce558SJens Axboe umode_t i_mode; 952c66ab6faSJens Axboe size_t len; 953c66ab6faSJens Axboe int i, flags; 954b92ce558SJens Axboe 955b92ce558SJens Axboe /* 956b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 957b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 958b92ce558SJens Axboe * piped splicing for that! 959b92ce558SJens Axboe */ 9600f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 961b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 962b92ce558SJens Axboe return -EINVAL; 963b92ce558SJens Axboe 964b92ce558SJens Axboe /* 965b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 966b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 967b92ce558SJens Axboe */ 968b92ce558SJens Axboe pipe = current->splice_pipe; 96949570e9bSJens Axboe if (unlikely(!pipe)) { 970b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 971b92ce558SJens Axboe if (!pipe) 972b92ce558SJens Axboe return -ENOMEM; 973b92ce558SJens Axboe 974b92ce558SJens Axboe /* 975b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 97600522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 977b92ce558SJens Axboe * PIPE_READERS appropriately. 978b92ce558SJens Axboe */ 979b92ce558SJens Axboe pipe->readers = 1; 980b92ce558SJens Axboe 981b92ce558SJens Axboe current->splice_pipe = pipe; 982b92ce558SJens Axboe } 983b92ce558SJens Axboe 984b92ce558SJens Axboe /* 98573d62d83SIngo Molnar * Do the splice. 986b92ce558SJens Axboe */ 987b92ce558SJens Axboe ret = 0; 988b92ce558SJens Axboe bytes = 0; 989c66ab6faSJens Axboe len = sd->total_len; 990c66ab6faSJens Axboe flags = sd->flags; 991c66ab6faSJens Axboe 992c66ab6faSJens Axboe /* 993c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 994c66ab6faSJens Axboe */ 995c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 996b92ce558SJens Axboe 997b92ce558SJens Axboe while (len) { 99851a92c0fSJens Axboe size_t read_len; 999a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 1000b92ce558SJens Axboe 1001bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 100251a92c0fSJens Axboe if (unlikely(ret <= 0)) 1003b92ce558SJens Axboe goto out_release; 1004b92ce558SJens Axboe 1005b92ce558SJens Axboe read_len = ret; 1006c66ab6faSJens Axboe sd->total_len = read_len; 1007b92ce558SJens Axboe 1008b92ce558SJens Axboe /* 1009b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1010b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1011b92ce558SJens Axboe * could get stuck data in the internal pipe: 1012b92ce558SJens Axboe */ 1013c66ab6faSJens Axboe ret = actor(pipe, sd); 1014a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1015a82c53a0STom Zanussi sd->pos = prev_pos; 1016b92ce558SJens Axboe goto out_release; 1017a82c53a0STom Zanussi } 1018b92ce558SJens Axboe 1019b92ce558SJens Axboe bytes += ret; 1020b92ce558SJens Axboe len -= ret; 1021bcd4f3acSJens Axboe sd->pos = pos; 1022b92ce558SJens Axboe 1023a82c53a0STom Zanussi if (ret < read_len) { 1024a82c53a0STom Zanussi sd->pos = prev_pos + ret; 102551a92c0fSJens Axboe goto out_release; 1026b92ce558SJens Axboe } 1027a82c53a0STom Zanussi } 1028b92ce558SJens Axboe 10299e97198dSJens Axboe done: 1030b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10319e97198dSJens Axboe file_accessed(in); 1032b92ce558SJens Axboe return bytes; 1033b92ce558SJens Axboe 1034b92ce558SJens Axboe out_release: 1035b92ce558SJens Axboe /* 1036b92ce558SJens Axboe * If we did an incomplete transfer we must release 1037b92ce558SJens Axboe * the pipe buffers in question: 1038b92ce558SJens Axboe */ 1039b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1040b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1041b92ce558SJens Axboe 1042b92ce558SJens Axboe if (buf->ops) { 1043b92ce558SJens Axboe buf->ops->release(pipe, buf); 1044b92ce558SJens Axboe buf->ops = NULL; 1045b92ce558SJens Axboe } 1046b92ce558SJens Axboe } 1047b92ce558SJens Axboe 10489e97198dSJens Axboe if (!bytes) 10499e97198dSJens Axboe bytes = ret; 1050b92ce558SJens Axboe 10519e97198dSJens Axboe goto done; 1052c66ab6faSJens Axboe } 1053c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1054c66ab6faSJens Axboe 1055c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1056c66ab6faSJens Axboe struct splice_desc *sd) 1057c66ab6faSJens Axboe { 10586a14b90bSJens Axboe struct file *file = sd->u.file; 1059c66ab6faSJens Axboe 1060c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1061c66ab6faSJens Axboe } 1062c66ab6faSJens Axboe 1063932cc6d4SJens Axboe /** 1064932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1065932cc6d4SJens Axboe * @in: file to splice from 1066932cc6d4SJens Axboe * @ppos: input file offset 1067932cc6d4SJens Axboe * @out: file to splice to 1068932cc6d4SJens Axboe * @len: number of bytes to splice 1069932cc6d4SJens Axboe * @flags: splice modifier flags 1070932cc6d4SJens Axboe * 1071932cc6d4SJens Axboe * Description: 1072932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1073932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1074932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1075932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1076932cc6d4SJens Axboe * 1077932cc6d4SJens Axboe */ 1078c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1079c66ab6faSJens Axboe size_t len, unsigned int flags) 1080c66ab6faSJens Axboe { 1081c66ab6faSJens Axboe struct splice_desc sd = { 1082c66ab6faSJens Axboe .len = len, 1083c66ab6faSJens Axboe .total_len = len, 1084c66ab6faSJens Axboe .flags = flags, 1085c66ab6faSJens Axboe .pos = *ppos, 10866a14b90bSJens Axboe .u.file = out, 1087c66ab6faSJens Axboe }; 108851a92c0fSJens Axboe long ret; 1089c66ab6faSJens Axboe 1090c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 109151a92c0fSJens Axboe if (ret > 0) 1092a82c53a0STom Zanussi *ppos = sd.pos; 109351a92c0fSJens Axboe 1094c66ab6faSJens Axboe return ret; 1095b92ce558SJens Axboe } 1096b92ce558SJens Axboe 109783f9135bSJens Axboe /* 1098ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1099ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1100ddac0d39SJens Axboe * pipe. 1101ddac0d39SJens Axboe */ 1102ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1103ddac0d39SJens Axboe { 1104ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1105ddac0d39SJens Axboe return inode->i_pipe; 1106ddac0d39SJens Axboe 1107ddac0d39SJens Axboe return NULL; 1108ddac0d39SJens Axboe } 1109ddac0d39SJens Axboe 1110ddac0d39SJens Axboe /* 111183f9135bSJens Axboe * Determine where to splice to/from. 111283f9135bSJens Axboe */ 1113529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1114529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1115529565dcSIngo Molnar size_t len, unsigned int flags) 11165274f052SJens Axboe { 11173a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1118cbb7e577SJens Axboe loff_t offset, *off; 1119a4514ebdSJens Axboe long ret; 11205274f052SJens Axboe 11210f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1122529565dcSIngo Molnar if (pipe) { 1123529565dcSIngo Molnar if (off_in) 1124529565dcSIngo Molnar return -ESPIPE; 1125b92ce558SJens Axboe if (off_out) { 1126b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1127b92ce558SJens Axboe return -EINVAL; 1128cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1129b92ce558SJens Axboe return -EFAULT; 1130cbb7e577SJens Axboe off = &offset; 1131cbb7e577SJens Axboe } else 1132cbb7e577SJens Axboe off = &out->f_pos; 1133529565dcSIngo Molnar 1134a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1135a4514ebdSJens Axboe 1136a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1137a4514ebdSJens Axboe ret = -EFAULT; 1138a4514ebdSJens Axboe 1139a4514ebdSJens Axboe return ret; 1140529565dcSIngo Molnar } 11415274f052SJens Axboe 11420f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1143529565dcSIngo Molnar if (pipe) { 1144529565dcSIngo Molnar if (off_out) 1145529565dcSIngo Molnar return -ESPIPE; 1146b92ce558SJens Axboe if (off_in) { 1147b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1148b92ce558SJens Axboe return -EINVAL; 1149cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1150b92ce558SJens Axboe return -EFAULT; 1151cbb7e577SJens Axboe off = &offset; 1152cbb7e577SJens Axboe } else 1153cbb7e577SJens Axboe off = &in->f_pos; 1154529565dcSIngo Molnar 1155a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1156a4514ebdSJens Axboe 1157a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1158a4514ebdSJens Axboe ret = -EFAULT; 1159a4514ebdSJens Axboe 1160a4514ebdSJens Axboe return ret; 1161529565dcSIngo Molnar } 11625274f052SJens Axboe 11635274f052SJens Axboe return -EINVAL; 11645274f052SJens Axboe } 11655274f052SJens Axboe 1166912d35f8SJens Axboe /* 1167912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1168912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1169912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1170912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1171912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1172912d35f8SJens Axboe */ 1173912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1174912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 11757afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1176912d35f8SJens Axboe { 1177912d35f8SJens Axboe int buffers = 0, error = 0; 1178912d35f8SJens Axboe 1179912d35f8SJens Axboe while (nr_vecs) { 1180912d35f8SJens Axboe unsigned long off, npages; 118175723957SLinus Torvalds struct iovec entry; 1182912d35f8SJens Axboe void __user *base; 1183912d35f8SJens Axboe size_t len; 1184912d35f8SJens Axboe int i; 1185912d35f8SJens Axboe 118675723957SLinus Torvalds error = -EFAULT; 1187bc40d73cSNick Piggin if (copy_from_user(&entry, iov, sizeof(entry))) 1188912d35f8SJens Axboe break; 118975723957SLinus Torvalds 119075723957SLinus Torvalds base = entry.iov_base; 119175723957SLinus Torvalds len = entry.iov_len; 1192912d35f8SJens Axboe 1193912d35f8SJens Axboe /* 1194912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1195912d35f8SJens Axboe */ 119675723957SLinus Torvalds error = 0; 1197912d35f8SJens Axboe if (unlikely(!len)) 1198912d35f8SJens Axboe break; 1199912d35f8SJens Axboe error = -EFAULT; 1200712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1201912d35f8SJens Axboe break; 1202912d35f8SJens Axboe 1203912d35f8SJens Axboe /* 1204912d35f8SJens Axboe * Get this base offset and number of pages, then map 1205912d35f8SJens Axboe * in the user pages. 1206912d35f8SJens Axboe */ 1207912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12087afa6fd0SJens Axboe 12097afa6fd0SJens Axboe /* 12107afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12117afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12127afa6fd0SJens Axboe */ 12137afa6fd0SJens Axboe error = -EINVAL; 12147afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12157afa6fd0SJens Axboe break; 12167afa6fd0SJens Axboe 1217912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1218912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1219912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1220912d35f8SJens Axboe 1221bc40d73cSNick Piggin error = get_user_pages_fast((unsigned long)base, npages, 1222bc40d73cSNick Piggin 0, &pages[buffers]); 1223912d35f8SJens Axboe 1224912d35f8SJens Axboe if (unlikely(error <= 0)) 1225912d35f8SJens Axboe break; 1226912d35f8SJens Axboe 1227912d35f8SJens Axboe /* 1228912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1229912d35f8SJens Axboe */ 1230912d35f8SJens Axboe for (i = 0; i < error; i++) { 12317591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1232912d35f8SJens Axboe 1233912d35f8SJens Axboe partial[buffers].offset = off; 1234912d35f8SJens Axboe partial[buffers].len = plen; 1235912d35f8SJens Axboe 1236912d35f8SJens Axboe off = 0; 1237912d35f8SJens Axboe len -= plen; 1238912d35f8SJens Axboe buffers++; 1239912d35f8SJens Axboe } 1240912d35f8SJens Axboe 1241912d35f8SJens Axboe /* 1242912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1243912d35f8SJens Axboe * means we have to move some of this into a pipe to 1244912d35f8SJens Axboe * be able to continue. 1245912d35f8SJens Axboe */ 1246912d35f8SJens Axboe if (len) 1247912d35f8SJens Axboe break; 1248912d35f8SJens Axboe 1249912d35f8SJens Axboe /* 1250912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1251912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1252912d35f8SJens Axboe * room for. 1253912d35f8SJens Axboe */ 1254912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1255912d35f8SJens Axboe break; 1256912d35f8SJens Axboe 1257912d35f8SJens Axboe nr_vecs--; 1258912d35f8SJens Axboe iov++; 1259912d35f8SJens Axboe } 1260912d35f8SJens Axboe 1261912d35f8SJens Axboe if (buffers) 1262912d35f8SJens Axboe return buffers; 1263912d35f8SJens Axboe 1264912d35f8SJens Axboe return error; 1265912d35f8SJens Axboe } 1266912d35f8SJens Axboe 12676a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12686a14b90bSJens Axboe struct splice_desc *sd) 12696a14b90bSJens Axboe { 12706a14b90bSJens Axboe char *src; 12716a14b90bSJens Axboe int ret; 12726a14b90bSJens Axboe 1273cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 12746a14b90bSJens Axboe if (unlikely(ret)) 12756a14b90bSJens Axboe return ret; 12766a14b90bSJens Axboe 12776a14b90bSJens Axboe /* 12786a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 12796a14b90bSJens Axboe * pages and doing an atomic copy 12806a14b90bSJens Axboe */ 12816a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 12826a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 12836a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 12846a14b90bSJens Axboe sd->len); 12856a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 12866a14b90bSJens Axboe if (!ret) { 12876a14b90bSJens Axboe ret = sd->len; 12886a14b90bSJens Axboe goto out; 12896a14b90bSJens Axboe } 12906a14b90bSJens Axboe } 12916a14b90bSJens Axboe 12926a14b90bSJens Axboe /* 12936a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 12946a14b90bSJens Axboe */ 12956a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 12966a14b90bSJens Axboe 12976a14b90bSJens Axboe ret = sd->len; 12986a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 12996a14b90bSJens Axboe ret = -EFAULT; 13006a14b90bSJens Axboe 13016866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 13026a14b90bSJens Axboe out: 13036a14b90bSJens Axboe if (ret > 0) 13046a14b90bSJens Axboe sd->u.userptr += ret; 13056a14b90bSJens Axboe return ret; 13066a14b90bSJens Axboe } 13076a14b90bSJens Axboe 13086a14b90bSJens Axboe /* 13096a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13106a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13116a14b90bSJens Axboe */ 13126a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13136a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13146a14b90bSJens Axboe { 13156a14b90bSJens Axboe struct pipe_inode_info *pipe; 13166a14b90bSJens Axboe struct splice_desc sd; 13176a14b90bSJens Axboe ssize_t size; 13186a14b90bSJens Axboe int error; 13196a14b90bSJens Axboe long ret; 13206a14b90bSJens Axboe 13216a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13226a14b90bSJens Axboe if (!pipe) 13236a14b90bSJens Axboe return -EBADF; 13246a14b90bSJens Axboe 13256a14b90bSJens Axboe if (pipe->inode) 13266a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13276a14b90bSJens Axboe 13286a14b90bSJens Axboe error = ret = 0; 13296a14b90bSJens Axboe while (nr_segs) { 13306a14b90bSJens Axboe void __user *base; 13316a14b90bSJens Axboe size_t len; 13326a14b90bSJens Axboe 13336a14b90bSJens Axboe /* 13346a14b90bSJens Axboe * Get user address base and length for this iovec. 13356a14b90bSJens Axboe */ 13366a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13376a14b90bSJens Axboe if (unlikely(error)) 13386a14b90bSJens Axboe break; 13396a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13406a14b90bSJens Axboe if (unlikely(error)) 13416a14b90bSJens Axboe break; 13426a14b90bSJens Axboe 13436a14b90bSJens Axboe /* 13446a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13456a14b90bSJens Axboe */ 13466a14b90bSJens Axboe if (unlikely(!len)) 13476a14b90bSJens Axboe break; 13486a14b90bSJens Axboe if (unlikely(!base)) { 13496a14b90bSJens Axboe error = -EFAULT; 13506a14b90bSJens Axboe break; 13516a14b90bSJens Axboe } 13526a14b90bSJens Axboe 13538811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 13548811930dSJens Axboe error = -EFAULT; 13558811930dSJens Axboe break; 13568811930dSJens Axboe } 13578811930dSJens Axboe 13586a14b90bSJens Axboe sd.len = 0; 13596a14b90bSJens Axboe sd.total_len = len; 13606a14b90bSJens Axboe sd.flags = flags; 13616a14b90bSJens Axboe sd.u.userptr = base; 13626a14b90bSJens Axboe sd.pos = 0; 13636a14b90bSJens Axboe 13646a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 13656a14b90bSJens Axboe if (size < 0) { 13666a14b90bSJens Axboe if (!ret) 13676a14b90bSJens Axboe ret = size; 13686a14b90bSJens Axboe 13696a14b90bSJens Axboe break; 13706a14b90bSJens Axboe } 13716a14b90bSJens Axboe 13726a14b90bSJens Axboe ret += size; 13736a14b90bSJens Axboe 13746a14b90bSJens Axboe if (size < len) 13756a14b90bSJens Axboe break; 13766a14b90bSJens Axboe 13776a14b90bSJens Axboe nr_segs--; 13786a14b90bSJens Axboe iov++; 13796a14b90bSJens Axboe } 13806a14b90bSJens Axboe 13816a14b90bSJens Axboe if (pipe->inode) 13826a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 13836a14b90bSJens Axboe 13846a14b90bSJens Axboe if (!ret) 13856a14b90bSJens Axboe ret = error; 13866a14b90bSJens Axboe 13876a14b90bSJens Axboe return ret; 13886a14b90bSJens Axboe } 13896a14b90bSJens Axboe 1390912d35f8SJens Axboe /* 1391912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1392912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1393912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1394912d35f8SJens Axboe */ 13956a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1396912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1397912d35f8SJens Axboe { 1398ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1399912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1400912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1401912d35f8SJens Axboe struct splice_pipe_desc spd = { 1402912d35f8SJens Axboe .pages = pages, 1403912d35f8SJens Axboe .partial = partial, 1404912d35f8SJens Axboe .flags = flags, 1405912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1406bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1407912d35f8SJens Axboe }; 1408912d35f8SJens Axboe 14090f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1410ddac0d39SJens Axboe if (!pipe) 1411912d35f8SJens Axboe return -EBADF; 1412912d35f8SJens Axboe 14137afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14147afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1415912d35f8SJens Axboe if (spd.nr_pages <= 0) 1416912d35f8SJens Axboe return spd.nr_pages; 1417912d35f8SJens Axboe 141800522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1419912d35f8SJens Axboe } 1420912d35f8SJens Axboe 14216a14b90bSJens Axboe /* 14226a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14236a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14246a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14256a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14266a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14276a14b90bSJens Axboe * solutions for that: 14286a14b90bSJens Axboe * 14296a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14306a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14316a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14326a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14336a14b90bSJens Axboe * 14346a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14356a14b90bSJens Axboe * 14366a14b90bSJens Axboe */ 1437912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1438912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1439912d35f8SJens Axboe { 1440912d35f8SJens Axboe struct file *file; 1441912d35f8SJens Axboe long error; 1442912d35f8SJens Axboe int fput; 1443912d35f8SJens Axboe 14446a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14456a14b90bSJens Axboe return -EINVAL; 14466a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14476a14b90bSJens Axboe return 0; 14486a14b90bSJens Axboe 1449912d35f8SJens Axboe error = -EBADF; 1450912d35f8SJens Axboe file = fget_light(fd, &fput); 1451912d35f8SJens Axboe if (file) { 1452912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14536a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14546a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14556a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1456912d35f8SJens Axboe 1457912d35f8SJens Axboe fput_light(file, fput); 1458912d35f8SJens Axboe } 1459912d35f8SJens Axboe 1460912d35f8SJens Axboe return error; 1461912d35f8SJens Axboe } 1462912d35f8SJens Axboe 1463529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1464529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1465529565dcSIngo Molnar size_t len, unsigned int flags) 14665274f052SJens Axboe { 14675274f052SJens Axboe long error; 14685274f052SJens Axboe struct file *in, *out; 14695274f052SJens Axboe int fput_in, fput_out; 14705274f052SJens Axboe 14715274f052SJens Axboe if (unlikely(!len)) 14725274f052SJens Axboe return 0; 14735274f052SJens Axboe 14745274f052SJens Axboe error = -EBADF; 1475529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 14765274f052SJens Axboe if (in) { 14775274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1478529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 14795274f052SJens Axboe if (out) { 14805274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1481529565dcSIngo Molnar error = do_splice(in, off_in, 1482529565dcSIngo Molnar out, off_out, 1483529565dcSIngo Molnar len, flags); 14845274f052SJens Axboe fput_light(out, fput_out); 14855274f052SJens Axboe } 14865274f052SJens Axboe } 14875274f052SJens Axboe 14885274f052SJens Axboe fput_light(in, fput_in); 14895274f052SJens Axboe } 14905274f052SJens Axboe 14915274f052SJens Axboe return error; 14925274f052SJens Axboe } 149370524490SJens Axboe 149470524490SJens Axboe /* 1495aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1496aadd06e5SJens Axboe * return an appropriate error. 1497aadd06e5SJens Axboe */ 1498aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1499aadd06e5SJens Axboe { 1500aadd06e5SJens Axboe int ret; 1501aadd06e5SJens Axboe 1502aadd06e5SJens Axboe /* 1503aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1504aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1505aadd06e5SJens Axboe */ 1506aadd06e5SJens Axboe if (pipe->nrbufs) 1507aadd06e5SJens Axboe return 0; 1508aadd06e5SJens Axboe 1509aadd06e5SJens Axboe ret = 0; 1510aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1511aadd06e5SJens Axboe 1512aadd06e5SJens Axboe while (!pipe->nrbufs) { 1513aadd06e5SJens Axboe if (signal_pending(current)) { 1514aadd06e5SJens Axboe ret = -ERESTARTSYS; 1515aadd06e5SJens Axboe break; 1516aadd06e5SJens Axboe } 1517aadd06e5SJens Axboe if (!pipe->writers) 1518aadd06e5SJens Axboe break; 1519aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1520aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1521aadd06e5SJens Axboe ret = -EAGAIN; 1522aadd06e5SJens Axboe break; 1523aadd06e5SJens Axboe } 1524aadd06e5SJens Axboe } 1525aadd06e5SJens Axboe pipe_wait(pipe); 1526aadd06e5SJens Axboe } 1527aadd06e5SJens Axboe 1528aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1529aadd06e5SJens Axboe return ret; 1530aadd06e5SJens Axboe } 1531aadd06e5SJens Axboe 1532aadd06e5SJens Axboe /* 1533aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1534aadd06e5SJens Axboe * return an appropriate error. 1535aadd06e5SJens Axboe */ 1536aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1537aadd06e5SJens Axboe { 1538aadd06e5SJens Axboe int ret; 1539aadd06e5SJens Axboe 1540aadd06e5SJens Axboe /* 1541aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1542aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1543aadd06e5SJens Axboe */ 1544aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1545aadd06e5SJens Axboe return 0; 1546aadd06e5SJens Axboe 1547aadd06e5SJens Axboe ret = 0; 1548aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1549aadd06e5SJens Axboe 1550aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1551aadd06e5SJens Axboe if (!pipe->readers) { 1552aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1553aadd06e5SJens Axboe ret = -EPIPE; 1554aadd06e5SJens Axboe break; 1555aadd06e5SJens Axboe } 1556aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1557aadd06e5SJens Axboe ret = -EAGAIN; 1558aadd06e5SJens Axboe break; 1559aadd06e5SJens Axboe } 1560aadd06e5SJens Axboe if (signal_pending(current)) { 1561aadd06e5SJens Axboe ret = -ERESTARTSYS; 1562aadd06e5SJens Axboe break; 1563aadd06e5SJens Axboe } 1564aadd06e5SJens Axboe pipe->waiting_writers++; 1565aadd06e5SJens Axboe pipe_wait(pipe); 1566aadd06e5SJens Axboe pipe->waiting_writers--; 1567aadd06e5SJens Axboe } 1568aadd06e5SJens Axboe 1569aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1570aadd06e5SJens Axboe return ret; 1571aadd06e5SJens Axboe } 1572aadd06e5SJens Axboe 1573aadd06e5SJens Axboe /* 157470524490SJens Axboe * Link contents of ipipe to opipe. 157570524490SJens Axboe */ 157670524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 157770524490SJens Axboe struct pipe_inode_info *opipe, 157870524490SJens Axboe size_t len, unsigned int flags) 157970524490SJens Axboe { 158070524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1581aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 158270524490SJens Axboe 158370524490SJens Axboe /* 158470524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 158570524490SJens Axboe * grabbing by inode address. Otherwise two different processes 158670524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 158770524490SJens Axboe */ 158862752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 158970524490SJens Axboe 1590aadd06e5SJens Axboe do { 159170524490SJens Axboe if (!opipe->readers) { 159270524490SJens Axboe send_sig(SIGPIPE, current, 0); 159370524490SJens Axboe if (!ret) 159470524490SJens Axboe ret = -EPIPE; 159570524490SJens Axboe break; 159670524490SJens Axboe } 159770524490SJens Axboe 159870524490SJens Axboe /* 1599aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1600aadd06e5SJens Axboe * output room, break. 160170524490SJens Axboe */ 1602aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1603aadd06e5SJens Axboe break; 1604aadd06e5SJens Axboe 1605aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1606aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 160770524490SJens Axboe 160870524490SJens Axboe /* 160970524490SJens Axboe * Get a reference to this pipe buffer, 161070524490SJens Axboe * so we can copy the contents over. 161170524490SJens Axboe */ 161270524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 161370524490SJens Axboe 161470524490SJens Axboe obuf = opipe->bufs + nbuf; 161570524490SJens Axboe *obuf = *ibuf; 161670524490SJens Axboe 16177afa6fd0SJens Axboe /* 16187afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16197afa6fd0SJens Axboe * prevent multiple steals of this page. 16207afa6fd0SJens Axboe */ 16217afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16227afa6fd0SJens Axboe 162370524490SJens Axboe if (obuf->len > len) 162470524490SJens Axboe obuf->len = len; 162570524490SJens Axboe 162670524490SJens Axboe opipe->nrbufs++; 162770524490SJens Axboe ret += obuf->len; 162870524490SJens Axboe len -= obuf->len; 1629aadd06e5SJens Axboe i++; 1630aadd06e5SJens Axboe } while (len); 163170524490SJens Axboe 163202cf01aeSJens Axboe /* 163302cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 163402cf01aeSJens Axboe * future, otherwise just return 0 163502cf01aeSJens Axboe */ 163602cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 163702cf01aeSJens Axboe ret = -EAGAIN; 163802cf01aeSJens Axboe 163962752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 164070524490SJens Axboe 1641aadd06e5SJens Axboe /* 1642aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1643aadd06e5SJens Axboe */ 1644aadd06e5SJens Axboe if (ret > 0) { 164570524490SJens Axboe smp_mb(); 164670524490SJens Axboe if (waitqueue_active(&opipe->wait)) 164770524490SJens Axboe wake_up_interruptible(&opipe->wait); 164870524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 164970524490SJens Axboe } 165070524490SJens Axboe 165170524490SJens Axboe return ret; 165270524490SJens Axboe } 165370524490SJens Axboe 165470524490SJens Axboe /* 165570524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 165670524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 165770524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 165870524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 165970524490SJens Axboe */ 166070524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 166170524490SJens Axboe unsigned int flags) 166270524490SJens Axboe { 16630f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 16640f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1665aadd06e5SJens Axboe int ret = -EINVAL; 166670524490SJens Axboe 166770524490SJens Axboe /* 1668aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1669aadd06e5SJens Axboe * copying the data. 167070524490SJens Axboe */ 1671aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1672aadd06e5SJens Axboe /* 1673aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1674aadd06e5SJens Axboe * ordering doesn't really matter. 1675aadd06e5SJens Axboe */ 1676aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1677aadd06e5SJens Axboe if (!ret) { 1678aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 167902cf01aeSJens Axboe if (!ret) 1680aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1681aadd06e5SJens Axboe } 1682aadd06e5SJens Axboe } 168370524490SJens Axboe 1684aadd06e5SJens Axboe return ret; 168570524490SJens Axboe } 168670524490SJens Axboe 168770524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 168870524490SJens Axboe { 168970524490SJens Axboe struct file *in; 169070524490SJens Axboe int error, fput_in; 169170524490SJens Axboe 169270524490SJens Axboe if (unlikely(!len)) 169370524490SJens Axboe return 0; 169470524490SJens Axboe 169570524490SJens Axboe error = -EBADF; 169670524490SJens Axboe in = fget_light(fdin, &fput_in); 169770524490SJens Axboe if (in) { 169870524490SJens Axboe if (in->f_mode & FMODE_READ) { 169970524490SJens Axboe int fput_out; 170070524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 170170524490SJens Axboe 170270524490SJens Axboe if (out) { 170370524490SJens Axboe if (out->f_mode & FMODE_WRITE) 170470524490SJens Axboe error = do_tee(in, out, len, flags); 170570524490SJens Axboe fput_light(out, fput_out); 170670524490SJens Axboe } 170770524490SJens Axboe } 170870524490SJens Axboe fput_light(in, fput_in); 170970524490SJens Axboe } 171070524490SJens Axboe 171170524490SJens Axboe return error; 171270524490SJens Axboe } 1713