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> 2408e552c6SKAMEZAWA Hiroyuki #include <linux/memcontrol.h> 255274f052SJens Axboe #include <linux/mm_inline.h> 265abc97aaSJens Axboe #include <linux/swap.h> 274f6f0bd2SJens Axboe #include <linux/writeback.h> 284f6f0bd2SJens Axboe #include <linux/buffer_head.h> 29a0f06780SJeff Garzik #include <linux/module.h> 304f6f0bd2SJens Axboe #include <linux/syscalls.h> 31912d35f8SJens Axboe #include <linux/uio.h> 3229ce2058SJames Morris #include <linux/security.h> 335274f052SJens Axboe 3483f9135bSJens Axboe /* 3583f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3683f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 3783f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 3883f9135bSJens Axboe * attempt to reuse this page for another destination. 3983f9135bSJens Axboe */ 4076ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 415abc97aaSJens Axboe struct pipe_buffer *buf) 425abc97aaSJens Axboe { 435abc97aaSJens Axboe struct page *page = buf->page; 449e94cd4fSJens Axboe struct address_space *mapping; 455abc97aaSJens Axboe 469e0267c2SJens Axboe lock_page(page); 479e0267c2SJens Axboe 489e94cd4fSJens Axboe mapping = page_mapping(page); 499e94cd4fSJens Axboe if (mapping) { 505abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 515abc97aaSJens Axboe 52ad8d6f0aSJens Axboe /* 539e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 549e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 559e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 569e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 579e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 589e94cd4fSJens Axboe * ensues. 59ad8d6f0aSJens Axboe */ 60ad8d6f0aSJens Axboe wait_on_page_writeback(page); 61ad8d6f0aSJens Axboe 62ca39d651SJens Axboe if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) 63ca39d651SJens Axboe goto out_unlock; 644f6f0bd2SJens Axboe 659e94cd4fSJens Axboe /* 669e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 679e94cd4fSJens Axboe * and return good. 689e94cd4fSJens Axboe */ 699e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 701432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 715abc97aaSJens Axboe return 0; 725abc97aaSJens Axboe } 739e94cd4fSJens Axboe } 749e94cd4fSJens Axboe 759e94cd4fSJens Axboe /* 769e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 779e94cd4fSJens Axboe * address space, unlock and return failure. 789e94cd4fSJens Axboe */ 79ca39d651SJens Axboe out_unlock: 809e94cd4fSJens Axboe unlock_page(page); 819e94cd4fSJens Axboe return 1; 829e94cd4fSJens Axboe } 835abc97aaSJens Axboe 8476ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 855274f052SJens Axboe struct pipe_buffer *buf) 865274f052SJens Axboe { 875274f052SJens Axboe page_cache_release(buf->page); 881432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 895274f052SJens Axboe } 905274f052SJens Axboe 910845718dSJens Axboe /* 920845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 930845718dSJens Axboe * is a page cache page, IO may be in flight. 940845718dSJens Axboe */ 95cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 965274f052SJens Axboe struct pipe_buffer *buf) 975274f052SJens Axboe { 985274f052SJens Axboe struct page *page = buf->page; 9949d0b21bSJens Axboe int err; 1005274f052SJens Axboe 1015274f052SJens Axboe if (!PageUptodate(page)) { 10249d0b21bSJens Axboe lock_page(page); 1035274f052SJens Axboe 10449d0b21bSJens Axboe /* 10549d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10673d62d83SIngo Molnar * splice, if this is the first page. 10749d0b21bSJens Axboe */ 1085274f052SJens Axboe if (!page->mapping) { 10949d0b21bSJens Axboe err = -ENODATA; 11049d0b21bSJens Axboe goto error; 1115274f052SJens Axboe } 1125274f052SJens Axboe 11349d0b21bSJens Axboe /* 11473d62d83SIngo Molnar * Uh oh, read-error from disk. 11549d0b21bSJens Axboe */ 11649d0b21bSJens Axboe if (!PageUptodate(page)) { 11749d0b21bSJens Axboe err = -EIO; 11849d0b21bSJens Axboe goto error; 11949d0b21bSJens Axboe } 12049d0b21bSJens Axboe 12149d0b21bSJens Axboe /* 122f84d7519SJens Axboe * Page is ok afterall, we are done. 12349d0b21bSJens Axboe */ 12449d0b21bSJens Axboe unlock_page(page); 12549d0b21bSJens Axboe } 12649d0b21bSJens Axboe 127f84d7519SJens Axboe return 0; 12849d0b21bSJens Axboe error: 12949d0b21bSJens Axboe unlock_page(page); 130f84d7519SJens Axboe return err; 13170524490SJens Axboe } 13270524490SJens Axboe 133d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1345274f052SJens Axboe .can_merge = 0, 135f84d7519SJens Axboe .map = generic_pipe_buf_map, 136f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 137cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1385274f052SJens Axboe .release = page_cache_pipe_buf_release, 1395abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 140f84d7519SJens Axboe .get = generic_pipe_buf_get, 1415274f052SJens Axboe }; 1425274f052SJens Axboe 143912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 144912d35f8SJens Axboe struct pipe_buffer *buf) 145912d35f8SJens Axboe { 1467afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 147912d35f8SJens Axboe return 1; 1487afa6fd0SJens Axboe 1491432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 150330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 151912d35f8SJens Axboe } 152912d35f8SJens Axboe 153d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 154912d35f8SJens Axboe .can_merge = 0, 155f84d7519SJens Axboe .map = generic_pipe_buf_map, 156f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 157cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 158912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 159912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 160f84d7519SJens Axboe .get = generic_pipe_buf_get, 161912d35f8SJens Axboe }; 162912d35f8SJens Axboe 163932cc6d4SJens Axboe /** 164932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 165932cc6d4SJens Axboe * @pipe: pipe to fill 166932cc6d4SJens Axboe * @spd: data to fill 167932cc6d4SJens Axboe * 168932cc6d4SJens Axboe * Description: 16979685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 170932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 171932cc6d4SJens Axboe * function will link that data to the pipe. 172932cc6d4SJens Axboe * 17383f9135bSJens Axboe */ 174d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 175912d35f8SJens Axboe struct splice_pipe_desc *spd) 1765274f052SJens Axboe { 17700de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 178912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1795274f052SJens Axboe 1805274f052SJens Axboe ret = 0; 1815274f052SJens Axboe do_wakeup = 0; 182912d35f8SJens Axboe page_nr = 0; 1835274f052SJens Axboe 1843a326a2cSIngo Molnar if (pipe->inode) 1853a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1865274f052SJens Axboe 1875274f052SJens Axboe for (;;) { 1883a326a2cSIngo Molnar if (!pipe->readers) { 1895274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1905274f052SJens Axboe if (!ret) 1915274f052SJens Axboe ret = -EPIPE; 1925274f052SJens Axboe break; 1935274f052SJens Axboe } 1945274f052SJens Axboe 1956f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1966f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1973a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1985274f052SJens Axboe 199912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 200912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 201912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 202497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 203912d35f8SJens Axboe buf->ops = spd->ops; 2047afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2057afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2067afa6fd0SJens Axboe 2076f767b04SJens Axboe pipe->nrbufs++; 208912d35f8SJens Axboe page_nr++; 209912d35f8SJens Axboe ret += buf->len; 210912d35f8SJens Axboe 2116f767b04SJens Axboe if (pipe->inode) 2125274f052SJens Axboe do_wakeup = 1; 2135274f052SJens Axboe 214912d35f8SJens Axboe if (!--spd->nr_pages) 2155274f052SJens Axboe break; 2166f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2175274f052SJens Axboe continue; 2185274f052SJens Axboe 2195274f052SJens Axboe break; 2205274f052SJens Axboe } 2215274f052SJens Axboe 222912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22329e35094SLinus Torvalds if (!ret) 22429e35094SLinus Torvalds ret = -EAGAIN; 22529e35094SLinus Torvalds break; 22629e35094SLinus Torvalds } 22729e35094SLinus Torvalds 2285274f052SJens Axboe if (signal_pending(current)) { 2295274f052SJens Axboe if (!ret) 2305274f052SJens Axboe ret = -ERESTARTSYS; 2315274f052SJens Axboe break; 2325274f052SJens Axboe } 2335274f052SJens Axboe 2345274f052SJens Axboe if (do_wakeup) { 235c0bd1f65SJens Axboe smp_mb(); 2363a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2373a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2383a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2395274f052SJens Axboe do_wakeup = 0; 2405274f052SJens Axboe } 2415274f052SJens Axboe 2423a326a2cSIngo Molnar pipe->waiting_writers++; 2433a326a2cSIngo Molnar pipe_wait(pipe); 2443a326a2cSIngo Molnar pipe->waiting_writers--; 2455274f052SJens Axboe } 2465274f052SJens Axboe 24702676e5aSJens Axboe if (pipe->inode) { 2483a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2495274f052SJens Axboe 2505274f052SJens Axboe if (do_wakeup) { 251c0bd1f65SJens Axboe smp_mb(); 2523a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2533a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2543a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2555274f052SJens Axboe } 25602676e5aSJens Axboe } 2575274f052SJens Axboe 25800de00bdSJens Axboe while (page_nr < spd_pages) 259bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2605274f052SJens Axboe 2615274f052SJens Axboe return ret; 2625274f052SJens Axboe } 2635274f052SJens Axboe 264bbdfc2f7SJens Axboe static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 265bbdfc2f7SJens Axboe { 266bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 267bbdfc2f7SJens Axboe } 268bbdfc2f7SJens Axboe 2693a326a2cSIngo Molnar static int 270cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 271cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 272cbb7e577SJens Axboe unsigned int flags) 2735274f052SJens Axboe { 2745274f052SJens Axboe struct address_space *mapping = in->f_mapping; 275d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 27616c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 277912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2785274f052SJens Axboe struct page *page; 27991ad66efSJens Axboe pgoff_t index, end_index; 28091ad66efSJens Axboe loff_t isize; 281eb20796bSJens Axboe int error, page_nr; 282912d35f8SJens Axboe struct splice_pipe_desc spd = { 283912d35f8SJens Axboe .pages = pages, 284912d35f8SJens Axboe .partial = partial, 285912d35f8SJens Axboe .flags = flags, 286912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 287bbdfc2f7SJens Axboe .spd_release = spd_release_page, 288912d35f8SJens Axboe }; 2895274f052SJens Axboe 290cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 291912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 292d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 293d8983910SFengguang Wu nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); 2945274f052SJens Axboe 2955274f052SJens Axboe /* 296eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29782aa5d61SJens Axboe */ 298eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 299431a4820SFengguang Wu index += spd.nr_pages; 300eb20796bSJens Axboe 3015274f052SJens Axboe /* 302eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 303431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 304eb20796bSJens Axboe */ 305431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 306cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 307cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 308431a4820SFengguang Wu 309932cc6d4SJens Axboe error = 0; 310eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 311eb20796bSJens Axboe /* 312eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 313eb20796bSJens Axboe * the first hole. 3145274f052SJens Axboe */ 3157480a904SJens Axboe page = find_get_page(mapping, index); 3167480a904SJens Axboe if (!page) { 317e27dedd8SJens Axboe /* 318eb20796bSJens Axboe * page didn't exist, allocate one. 3197480a904SJens Axboe */ 3207480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3215274f052SJens Axboe if (!page) 3225274f052SJens Axboe break; 3235274f052SJens Axboe 3247480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3254cd13504SHugh Dickins mapping_gfp_mask(mapping)); 3265274f052SJens Axboe if (unlikely(error)) { 3275274f052SJens Axboe page_cache_release(page); 328a0548871SJens Axboe if (error == -EEXIST) 329a0548871SJens Axboe continue; 3305274f052SJens Axboe break; 3315274f052SJens Axboe } 332eb20796bSJens Axboe /* 333eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 334eb20796bSJens Axboe * to avoid convoluting the logic below even more. 335eb20796bSJens Axboe */ 336eb20796bSJens Axboe unlock_page(page); 3375274f052SJens Axboe } 3387480a904SJens Axboe 339eb20796bSJens Axboe pages[spd.nr_pages++] = page; 340eb20796bSJens Axboe index++; 341eb20796bSJens Axboe } 342eb20796bSJens Axboe 343eb20796bSJens Axboe /* 344eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 345eb20796bSJens Axboe * pages, fill in the partial map, etc. 346eb20796bSJens Axboe */ 347eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 348eb20796bSJens Axboe nr_pages = spd.nr_pages; 349eb20796bSJens Axboe spd.nr_pages = 0; 350eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 351eb20796bSJens Axboe unsigned int this_len; 352eb20796bSJens Axboe 353eb20796bSJens Axboe if (!len) 354eb20796bSJens Axboe break; 355eb20796bSJens Axboe 356eb20796bSJens Axboe /* 357eb20796bSJens Axboe * this_len is the max we'll use from this page 358eb20796bSJens Axboe */ 359eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 360eb20796bSJens Axboe page = pages[page_nr]; 361eb20796bSJens Axboe 362a08a166fSFengguang Wu if (PageReadahead(page)) 363cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 364d8983910SFengguang Wu page, index, req_pages - page_nr); 365a08a166fSFengguang Wu 3667480a904SJens Axboe /* 3677480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3687480a904SJens Axboe */ 3697480a904SJens Axboe if (!PageUptodate(page)) { 370c4f895cbSJens Axboe /* 371c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 372c4f895cbSJens Axboe * for an in-flight io page 373c4f895cbSJens Axboe */ 3749ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 375529ae9aaSNick Piggin if (!trylock_page(page)) { 3768191ecd1SJens Axboe error = -EAGAIN; 377c4f895cbSJens Axboe break; 3788191ecd1SJens Axboe } 3799ae9d68cSFengguang Wu } else 3807480a904SJens Axboe lock_page(page); 3817480a904SJens Axboe 3827480a904SJens Axboe /* 38332502b84SMiklos Szeredi * Page was truncated, or invalidated by the 38432502b84SMiklos Szeredi * filesystem. Redo the find/create, but this time the 38532502b84SMiklos Szeredi * page is kept locked, so there's no chance of another 38632502b84SMiklos Szeredi * race with truncate/invalidate. 3877480a904SJens Axboe */ 3887480a904SJens Axboe if (!page->mapping) { 3897480a904SJens Axboe unlock_page(page); 39032502b84SMiklos Szeredi page = find_or_create_page(mapping, index, 39132502b84SMiklos Szeredi mapping_gfp_mask(mapping)); 39232502b84SMiklos Szeredi 39332502b84SMiklos Szeredi if (!page) { 39432502b84SMiklos Szeredi error = -ENOMEM; 3957480a904SJens Axboe break; 3967480a904SJens Axboe } 39732502b84SMiklos Szeredi page_cache_release(pages[page_nr]); 39832502b84SMiklos Szeredi pages[page_nr] = page; 39932502b84SMiklos Szeredi } 4007480a904SJens Axboe /* 4017480a904SJens Axboe * page was already under io and is now done, great 4027480a904SJens Axboe */ 4037480a904SJens Axboe if (PageUptodate(page)) { 4047480a904SJens Axboe unlock_page(page); 4057480a904SJens Axboe goto fill_it; 4067480a904SJens Axboe } 4077480a904SJens Axboe 4087480a904SJens Axboe /* 4097480a904SJens Axboe * need to read in the page 4107480a904SJens Axboe */ 4117480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4127480a904SJens Axboe if (unlikely(error)) { 413eb20796bSJens Axboe /* 414eb20796bSJens Axboe * We really should re-lookup the page here, 415eb20796bSJens Axboe * but it complicates things a lot. Instead 416eb20796bSJens Axboe * lets just do what we already stored, and 417eb20796bSJens Axboe * we'll get it the next time we are called. 418eb20796bSJens Axboe */ 4197480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 420eb20796bSJens Axboe error = 0; 421eb20796bSJens Axboe 4227480a904SJens Axboe break; 4237480a904SJens Axboe } 424620a324bSJens Axboe } 425620a324bSJens Axboe fill_it: 42691ad66efSJens Axboe /* 427620a324bSJens Axboe * i_size must be checked after PageUptodate. 42891ad66efSJens Axboe */ 42991ad66efSJens Axboe isize = i_size_read(mapping->host); 43091ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 431eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 43291ad66efSJens Axboe break; 43391ad66efSJens Axboe 43491ad66efSJens Axboe /* 43591ad66efSJens Axboe * if this is the last page, see if we need to shrink 43691ad66efSJens Axboe * the length and stop 43791ad66efSJens Axboe */ 43891ad66efSJens Axboe if (end_index == index) { 439475ecadeSHugh Dickins unsigned int plen; 440475ecadeSHugh Dickins 441475ecadeSHugh Dickins /* 442475ecadeSHugh Dickins * max good bytes in this page 443475ecadeSHugh Dickins */ 444475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 445475ecadeSHugh Dickins if (plen <= loff) 44691ad66efSJens Axboe break; 447475ecadeSHugh Dickins 44891ad66efSJens Axboe /* 44991ad66efSJens Axboe * force quit after adding this page 45091ad66efSJens Axboe */ 451475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 452eb20796bSJens Axboe len = this_len; 45391ad66efSJens Axboe } 454620a324bSJens Axboe 455eb20796bSJens Axboe partial[page_nr].offset = loff; 456eb20796bSJens Axboe partial[page_nr].len = this_len; 45782aa5d61SJens Axboe len -= this_len; 45891ad66efSJens Axboe loff = 0; 459eb20796bSJens Axboe spd.nr_pages++; 460eb20796bSJens Axboe index++; 4615274f052SJens Axboe } 4625274f052SJens Axboe 463eb20796bSJens Axboe /* 464475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 465eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 466eb20796bSJens Axboe */ 467eb20796bSJens Axboe while (page_nr < nr_pages) 468eb20796bSJens Axboe page_cache_release(pages[page_nr++]); 469f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 470eb20796bSJens Axboe 471912d35f8SJens Axboe if (spd.nr_pages) 47200522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 47316c523ddSJens Axboe 4747480a904SJens Axboe return error; 4755274f052SJens Axboe } 4765274f052SJens Axboe 47783f9135bSJens Axboe /** 47883f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 47983f9135bSJens Axboe * @in: file to splice from 480932cc6d4SJens Axboe * @ppos: position in @in 48183f9135bSJens Axboe * @pipe: pipe to splice to 48283f9135bSJens Axboe * @len: number of bytes to splice 48383f9135bSJens Axboe * @flags: splice modifier flags 48483f9135bSJens Axboe * 485932cc6d4SJens Axboe * Description: 486932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 487932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 488932cc6d4SJens Axboe * a readpage() hook. 489932cc6d4SJens Axboe * 49083f9135bSJens Axboe */ 491cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 492cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 493cbb7e577SJens Axboe unsigned int flags) 4945274f052SJens Axboe { 495d366d398SJens Axboe loff_t isize, left; 4968191ecd1SJens Axboe int ret; 497d366d398SJens Axboe 498d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 499d366d398SJens Axboe if (unlikely(*ppos >= isize)) 500d366d398SJens Axboe return 0; 501d366d398SJens Axboe 502d366d398SJens Axboe left = isize - *ppos; 503d366d398SJens Axboe if (unlikely(left < len)) 504d366d398SJens Axboe len = left; 5055274f052SJens Axboe 506cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 5078191ecd1SJens Axboe if (ret > 0) 508cbb7e577SJens Axboe *ppos += ret; 5095274f052SJens Axboe 5105274f052SJens Axboe return ret; 5115274f052SJens Axboe } 5125274f052SJens Axboe 513059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 514059a8f37SJens Axboe 5155274f052SJens Axboe /* 5164f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 517016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 5185274f052SJens Axboe */ 51976ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 5205274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 5215274f052SJens Axboe { 5226a14b90bSJens Axboe struct file *file = sd->u.file; 5235274f052SJens Axboe loff_t pos = sd->pos; 524f84d7519SJens Axboe int ret, more; 5255274f052SJens Axboe 526cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 527f84d7519SJens Axboe if (!ret) { 528b2b39fa4SJens Axboe more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; 5295274f052SJens Axboe 530f84d7519SJens Axboe ret = file->f_op->sendpage(file, buf->page, buf->offset, 531f84d7519SJens Axboe sd->len, &pos, more); 532f84d7519SJens Axboe } 5335274f052SJens Axboe 534016b661eSJens Axboe return ret; 5355274f052SJens Axboe } 5365274f052SJens Axboe 5375274f052SJens Axboe /* 5385274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 5395274f052SJens Axboe * basically three cases: 5405274f052SJens Axboe * 5415274f052SJens Axboe * - Destination page already exists in the address space and there 5425274f052SJens Axboe * are users of it. For that case we have no other option that 5435274f052SJens Axboe * copying the data. Tough luck. 5445274f052SJens Axboe * - Destination page already exists in the address space, but there 5455274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 5465274f052SJens Axboe * through to last case. 5475274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 5485274f052SJens Axboe * the page cache and avoid the copy. 5495274f052SJens Axboe * 55083f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 55183f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 55283f9135bSJens Axboe * file address space page cache. This is possible if no one else has 55383f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 55483f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 55583f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 5565274f052SJens Axboe */ 55776ad4d11SJens Axboe static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 5585274f052SJens Axboe struct splice_desc *sd) 5595274f052SJens Axboe { 5606a14b90bSJens Axboe struct file *file = sd->u.file; 5615274f052SJens Axboe struct address_space *mapping = file->f_mapping; 562016b661eSJens Axboe unsigned int offset, this_len; 5635274f052SJens Axboe struct page *page; 564afddba49SNick Piggin void *fsdata; 5653e7ee3e7SJens Axboe int ret; 5665274f052SJens Axboe 5675274f052SJens Axboe /* 56849d0b21bSJens Axboe * make sure the data in this buffer is uptodate 5695274f052SJens Axboe */ 570cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 571f84d7519SJens Axboe if (unlikely(ret)) 572f84d7519SJens Axboe return ret; 5735274f052SJens Axboe 5745274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 5755274f052SJens Axboe 576016b661eSJens Axboe this_len = sd->len; 577016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 578016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 579016b661eSJens Axboe 580afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 581afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 5829e0267c2SJens Axboe if (unlikely(ret)) 583afddba49SNick Piggin goto out; 5845274f052SJens Axboe 5850568b409SJens Axboe if (buf->page != page) { 586f84d7519SJens Axboe /* 587f84d7519SJens Axboe * Careful, ->map() uses KM_USER0! 588f84d7519SJens Axboe */ 58976ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 590f84d7519SJens Axboe char *dst = kmap_atomic(page, KM_USER1); 5915abc97aaSJens Axboe 592016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 5935274f052SJens Axboe flush_dcache_page(page); 594f84d7519SJens Axboe kunmap_atomic(dst, KM_USER1); 59576ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 5965abc97aaSJens Axboe } 597afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 598afddba49SNick Piggin page, fsdata); 5990568b409SJens Axboe out: 6005274f052SJens Axboe return ret; 6015274f052SJens Axboe } 6025274f052SJens Axboe 603932cc6d4SJens Axboe /** 604932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 605932cc6d4SJens Axboe * @pipe: pipe to splice from 606932cc6d4SJens Axboe * @sd: information to @actor 607932cc6d4SJens Axboe * @actor: handler that splices the data 608932cc6d4SJens Axboe * 609932cc6d4SJens Axboe * Description: 610932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 611932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 612932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 613932cc6d4SJens Axboe * pipe_to_user. 614932cc6d4SJens Axboe * 61583f9135bSJens Axboe */ 616c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 617c66ab6faSJens Axboe splice_actor *actor) 6185274f052SJens Axboe { 6195274f052SJens Axboe int ret, do_wakeup, err; 6205274f052SJens Axboe 6215274f052SJens Axboe ret = 0; 6225274f052SJens Axboe do_wakeup = 0; 6235274f052SJens Axboe 6245274f052SJens Axboe for (;;) { 6256f767b04SJens Axboe if (pipe->nrbufs) { 6266f767b04SJens Axboe struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 627d4c3cca9SEric Dumazet const struct pipe_buf_operations *ops = buf->ops; 6285274f052SJens Axboe 629c66ab6faSJens Axboe sd->len = buf->len; 630c66ab6faSJens Axboe if (sd->len > sd->total_len) 631c66ab6faSJens Axboe sd->len = sd->total_len; 6325274f052SJens Axboe 633c66ab6faSJens Axboe err = actor(pipe, buf, sd); 634016b661eSJens Axboe if (err <= 0) { 6355274f052SJens Axboe if (!ret && err != -ENODATA) 6365274f052SJens Axboe ret = err; 6375274f052SJens Axboe 6385274f052SJens Axboe break; 6395274f052SJens Axboe } 6405274f052SJens Axboe 641016b661eSJens Axboe ret += err; 642016b661eSJens Axboe buf->offset += err; 643016b661eSJens Axboe buf->len -= err; 644016b661eSJens Axboe 645c66ab6faSJens Axboe sd->len -= err; 646c66ab6faSJens Axboe sd->pos += err; 647c66ab6faSJens Axboe sd->total_len -= err; 648c66ab6faSJens Axboe if (sd->len) 649016b661eSJens Axboe continue; 65073d62d83SIngo Molnar 6515274f052SJens Axboe if (!buf->len) { 6525274f052SJens Axboe buf->ops = NULL; 6533a326a2cSIngo Molnar ops->release(pipe, buf); 6546f767b04SJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); 6556f767b04SJens Axboe pipe->nrbufs--; 6566f767b04SJens Axboe if (pipe->inode) 6575274f052SJens Axboe do_wakeup = 1; 6585274f052SJens Axboe } 6595274f052SJens Axboe 660c66ab6faSJens Axboe if (!sd->total_len) 6615274f052SJens Axboe break; 6625274f052SJens Axboe } 6635274f052SJens Axboe 6646f767b04SJens Axboe if (pipe->nrbufs) 6655274f052SJens Axboe continue; 6663a326a2cSIngo Molnar if (!pipe->writers) 6675274f052SJens Axboe break; 6683a326a2cSIngo Molnar if (!pipe->waiting_writers) { 6695274f052SJens Axboe if (ret) 6705274f052SJens Axboe break; 6715274f052SJens Axboe } 6725274f052SJens Axboe 673c66ab6faSJens Axboe if (sd->flags & SPLICE_F_NONBLOCK) { 67429e35094SLinus Torvalds if (!ret) 67529e35094SLinus Torvalds ret = -EAGAIN; 67629e35094SLinus Torvalds break; 67729e35094SLinus Torvalds } 67829e35094SLinus Torvalds 6795274f052SJens Axboe if (signal_pending(current)) { 6805274f052SJens Axboe if (!ret) 6815274f052SJens Axboe ret = -ERESTARTSYS; 6825274f052SJens Axboe break; 6835274f052SJens Axboe } 6845274f052SJens Axboe 6855274f052SJens Axboe if (do_wakeup) { 686c0bd1f65SJens Axboe smp_mb(); 6873a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6883a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 6893a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 6905274f052SJens Axboe do_wakeup = 0; 6915274f052SJens Axboe } 6925274f052SJens Axboe 6933a326a2cSIngo Molnar pipe_wait(pipe); 6945274f052SJens Axboe } 6955274f052SJens Axboe 6965274f052SJens Axboe if (do_wakeup) { 697c0bd1f65SJens Axboe smp_mb(); 6983a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 6993a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 7003a326a2cSIngo Molnar kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 7015274f052SJens Axboe } 7025274f052SJens Axboe 7035274f052SJens Axboe return ret; 7045274f052SJens Axboe } 70540bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 7065274f052SJens Axboe 707932cc6d4SJens Axboe /** 708932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 709932cc6d4SJens Axboe * @pipe: pipe to splice from 710932cc6d4SJens Axboe * @out: file to splice to 711932cc6d4SJens Axboe * @ppos: position in @out 712932cc6d4SJens Axboe * @len: how many bytes to splice 713932cc6d4SJens Axboe * @flags: splice modifier flags 714932cc6d4SJens Axboe * @actor: handler that splices the data 715932cc6d4SJens Axboe * 716932cc6d4SJens Axboe * Description: 717932cc6d4SJens Axboe * See __splice_from_pipe. This function locks the input and output inodes, 718932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 719932cc6d4SJens Axboe * 720932cc6d4SJens Axboe */ 7216da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 7226da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 7236da61809SMark Fasheh splice_actor *actor) 7246da61809SMark Fasheh { 7256da61809SMark Fasheh ssize_t ret; 7266da61809SMark Fasheh struct inode *inode = out->f_mapping->host; 727c66ab6faSJens Axboe struct splice_desc sd = { 728c66ab6faSJens Axboe .total_len = len, 729c66ab6faSJens Axboe .flags = flags, 730c66ab6faSJens Axboe .pos = *ppos, 7316a14b90bSJens Axboe .u.file = out, 732c66ab6faSJens Axboe }; 7336da61809SMark Fasheh 7346da61809SMark Fasheh /* 7354e02ed4bSNick Piggin * The actor worker might be calling ->write_begin and 7364e02ed4bSNick Piggin * ->write_end. Most of the time, these expect i_mutex to 7376da61809SMark Fasheh * be held. Since this may result in an ABBA deadlock with 7386da61809SMark Fasheh * pipe->inode, we have to order lock acquiry here. 7396da61809SMark Fasheh */ 7406da61809SMark Fasheh inode_double_lock(inode, pipe->inode); 741c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 7426da61809SMark Fasheh inode_double_unlock(inode, pipe->inode); 7436da61809SMark Fasheh 7446da61809SMark Fasheh return ret; 7456da61809SMark Fasheh } 7466da61809SMark Fasheh 7476da61809SMark Fasheh /** 7486da61809SMark Fasheh * generic_file_splice_write_nolock - generic_file_splice_write without mutexes 7496da61809SMark Fasheh * @pipe: pipe info 7506da61809SMark Fasheh * @out: file to write to 751932cc6d4SJens Axboe * @ppos: position in @out 7526da61809SMark Fasheh * @len: number of bytes to splice 7536da61809SMark Fasheh * @flags: splice modifier flags 7546da61809SMark Fasheh * 755932cc6d4SJens Axboe * Description: 7566da61809SMark Fasheh * Will either move or copy pages (determined by @flags options) from 7576da61809SMark Fasheh * the given pipe inode to the given file. The caller is responsible 7586da61809SMark Fasheh * for acquiring i_mutex on both inodes. 7596da61809SMark Fasheh * 7606da61809SMark Fasheh */ 7616da61809SMark Fasheh ssize_t 7626da61809SMark Fasheh generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, 7636da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags) 7646da61809SMark Fasheh { 7656da61809SMark Fasheh struct address_space *mapping = out->f_mapping; 7666da61809SMark Fasheh struct inode *inode = mapping->host; 767c66ab6faSJens Axboe struct splice_desc sd = { 768c66ab6faSJens Axboe .total_len = len, 769c66ab6faSJens Axboe .flags = flags, 770c66ab6faSJens Axboe .pos = *ppos, 7716a14b90bSJens Axboe .u.file = out, 772c66ab6faSJens Axboe }; 7736da61809SMark Fasheh ssize_t ret; 7746da61809SMark Fasheh int err; 7756da61809SMark Fasheh 7762f1936b8SMiklos Szeredi err = file_remove_suid(out); 7778c34e2d6SJens Axboe if (unlikely(err)) 7788c34e2d6SJens Axboe return err; 7798c34e2d6SJens Axboe 780c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 7816da61809SMark Fasheh if (ret > 0) { 78217ee4f49SJens Axboe unsigned long nr_pages; 78317ee4f49SJens Axboe 7846da61809SMark Fasheh *ppos += ret; 78517ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 7866da61809SMark Fasheh 7876da61809SMark Fasheh /* 7886da61809SMark Fasheh * If file or inode is SYNC and we actually wrote some data, 7896da61809SMark Fasheh * sync it. 7906da61809SMark Fasheh */ 7916da61809SMark Fasheh if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 7926da61809SMark Fasheh err = generic_osync_inode(inode, mapping, 7936da61809SMark Fasheh OSYNC_METADATA|OSYNC_DATA); 7946da61809SMark Fasheh 7956da61809SMark Fasheh if (err) 7966da61809SMark Fasheh ret = err; 7976da61809SMark Fasheh } 79817ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 7996da61809SMark Fasheh } 8006da61809SMark Fasheh 8016da61809SMark Fasheh return ret; 8026da61809SMark Fasheh } 8036da61809SMark Fasheh 8046da61809SMark Fasheh EXPORT_SYMBOL(generic_file_splice_write_nolock); 8056da61809SMark Fasheh 80683f9135bSJens Axboe /** 80783f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 8083a326a2cSIngo Molnar * @pipe: pipe info 80983f9135bSJens Axboe * @out: file to write to 810932cc6d4SJens Axboe * @ppos: position in @out 81183f9135bSJens Axboe * @len: number of bytes to splice 81283f9135bSJens Axboe * @flags: splice modifier flags 81383f9135bSJens Axboe * 814932cc6d4SJens Axboe * Description: 81583f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 81683f9135bSJens Axboe * the given pipe inode to the given file. 81783f9135bSJens Axboe * 81883f9135bSJens Axboe */ 8193a326a2cSIngo Molnar ssize_t 8203a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 821cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8225274f052SJens Axboe { 8234f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 8248c34e2d6SJens Axboe struct inode *inode = mapping->host; 8257f3d4ee1SMiklos Szeredi struct splice_desc sd = { 8267f3d4ee1SMiklos Szeredi .total_len = len, 8277f3d4ee1SMiklos Szeredi .flags = flags, 8287f3d4ee1SMiklos Szeredi .pos = *ppos, 8297f3d4ee1SMiklos Szeredi .u.file = out, 8307f3d4ee1SMiklos Szeredi }; 8313a326a2cSIngo Molnar ssize_t ret; 8328c34e2d6SJens Axboe 8337f3d4ee1SMiklos Szeredi inode_double_lock(inode, pipe->inode); 8342f1936b8SMiklos Szeredi ret = file_remove_suid(out); 8357f3d4ee1SMiklos Szeredi if (likely(!ret)) 8367f3d4ee1SMiklos Szeredi ret = __splice_from_pipe(pipe, &sd, pipe_to_file); 8377f3d4ee1SMiklos Szeredi inode_double_unlock(inode, pipe->inode); 838a4514ebdSJens Axboe if (ret > 0) { 83917ee4f49SJens Axboe unsigned long nr_pages; 84017ee4f49SJens Axboe 841a4514ebdSJens Axboe *ppos += ret; 84217ee4f49SJens Axboe nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 8434f6f0bd2SJens Axboe 8444f6f0bd2SJens Axboe /* 845a4514ebdSJens Axboe * If file or inode is SYNC and we actually wrote some data, 846a4514ebdSJens Axboe * sync it. 8474f6f0bd2SJens Axboe */ 848a4514ebdSJens Axboe if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { 8497f3d4ee1SMiklos Szeredi int err; 8507f3d4ee1SMiklos Szeredi 8514f6f0bd2SJens Axboe mutex_lock(&inode->i_mutex); 852a4514ebdSJens Axboe err = generic_osync_inode(inode, mapping, 8534f6f0bd2SJens Axboe OSYNC_METADATA|OSYNC_DATA); 8544f6f0bd2SJens Axboe mutex_unlock(&inode->i_mutex); 8554f6f0bd2SJens Axboe 8564f6f0bd2SJens Axboe if (err) 8574f6f0bd2SJens Axboe ret = err; 8584f6f0bd2SJens Axboe } 85917ee4f49SJens Axboe balance_dirty_pages_ratelimited_nr(mapping, nr_pages); 860a4514ebdSJens Axboe } 8614f6f0bd2SJens Axboe 8624f6f0bd2SJens Axboe return ret; 8635274f052SJens Axboe } 8645274f052SJens Axboe 865059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 866059a8f37SJens Axboe 86783f9135bSJens Axboe /** 86883f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 869932cc6d4SJens Axboe * @pipe: pipe to splice from 87083f9135bSJens Axboe * @out: socket to write to 871932cc6d4SJens Axboe * @ppos: position in @out 87283f9135bSJens Axboe * @len: number of bytes to splice 87383f9135bSJens Axboe * @flags: splice modifier flags 87483f9135bSJens Axboe * 875932cc6d4SJens Axboe * Description: 87683f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 87783f9135bSJens Axboe * is involved. 87883f9135bSJens Axboe * 87983f9135bSJens Axboe */ 8803a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 881cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8825274f052SJens Axboe { 88300522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8845274f052SJens Axboe } 8855274f052SJens Axboe 886059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 887a0f06780SJeff Garzik 88883f9135bSJens Axboe /* 88983f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 89083f9135bSJens Axboe */ 8913a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 892cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8935274f052SJens Axboe { 8945274f052SJens Axboe int ret; 8955274f052SJens Axboe 89649570e9bSJens Axboe if (unlikely(!out->f_op || !out->f_op->splice_write)) 8975274f052SJens Axboe return -EINVAL; 8985274f052SJens Axboe 89949570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 9005274f052SJens Axboe return -EBADF; 9015274f052SJens Axboe 902efc968d4SLinus Torvalds if (unlikely(out->f_flags & O_APPEND)) 903efc968d4SLinus Torvalds return -EINVAL; 904efc968d4SLinus Torvalds 905cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9065274f052SJens Axboe if (unlikely(ret < 0)) 9075274f052SJens Axboe return ret; 9085274f052SJens Axboe 909cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9105274f052SJens Axboe } 9115274f052SJens Axboe 91283f9135bSJens Axboe /* 91383f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 91483f9135bSJens Axboe */ 915cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 916cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 917cbb7e577SJens Axboe unsigned int flags) 9185274f052SJens Axboe { 9195274f052SJens Axboe int ret; 9205274f052SJens Axboe 92149570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9225274f052SJens Axboe return -EINVAL; 9235274f052SJens Axboe 92449570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9255274f052SJens Axboe return -EBADF; 9265274f052SJens Axboe 927cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9285274f052SJens Axboe if (unlikely(ret < 0)) 9295274f052SJens Axboe return ret; 9305274f052SJens Axboe 931cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9325274f052SJens Axboe } 9335274f052SJens Axboe 934932cc6d4SJens Axboe /** 935932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 936932cc6d4SJens Axboe * @in: file to splice from 937932cc6d4SJens Axboe * @sd: actor information on where to splice to 938932cc6d4SJens Axboe * @actor: handles the data splicing 939932cc6d4SJens Axboe * 940932cc6d4SJens Axboe * Description: 941932cc6d4SJens Axboe * This is a special case helper to splice directly between two 942932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 943932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 944932cc6d4SJens Axboe * that process. 945932cc6d4SJens Axboe * 946c66ab6faSJens Axboe */ 947c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 948c66ab6faSJens Axboe splice_direct_actor *actor) 949b92ce558SJens Axboe { 950b92ce558SJens Axboe struct pipe_inode_info *pipe; 951b92ce558SJens Axboe long ret, bytes; 952b92ce558SJens Axboe umode_t i_mode; 953c66ab6faSJens Axboe size_t len; 954c66ab6faSJens Axboe int i, flags; 955b92ce558SJens Axboe 956b92ce558SJens Axboe /* 957b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 958b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 959b92ce558SJens Axboe * piped splicing for that! 960b92ce558SJens Axboe */ 9610f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 962b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 963b92ce558SJens Axboe return -EINVAL; 964b92ce558SJens Axboe 965b92ce558SJens Axboe /* 966b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 967b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 968b92ce558SJens Axboe */ 969b92ce558SJens Axboe pipe = current->splice_pipe; 97049570e9bSJens Axboe if (unlikely(!pipe)) { 971b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 972b92ce558SJens Axboe if (!pipe) 973b92ce558SJens Axboe return -ENOMEM; 974b92ce558SJens Axboe 975b92ce558SJens Axboe /* 976b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 97700522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 978b92ce558SJens Axboe * PIPE_READERS appropriately. 979b92ce558SJens Axboe */ 980b92ce558SJens Axboe pipe->readers = 1; 981b92ce558SJens Axboe 982b92ce558SJens Axboe current->splice_pipe = pipe; 983b92ce558SJens Axboe } 984b92ce558SJens Axboe 985b92ce558SJens Axboe /* 98673d62d83SIngo Molnar * Do the splice. 987b92ce558SJens Axboe */ 988b92ce558SJens Axboe ret = 0; 989b92ce558SJens Axboe bytes = 0; 990c66ab6faSJens Axboe len = sd->total_len; 991c66ab6faSJens Axboe flags = sd->flags; 992c66ab6faSJens Axboe 993c66ab6faSJens Axboe /* 994c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 995c66ab6faSJens Axboe */ 996c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 997b92ce558SJens Axboe 998b92ce558SJens Axboe while (len) { 99951a92c0fSJens Axboe size_t read_len; 1000a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 1001b92ce558SJens Axboe 1002bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 100351a92c0fSJens Axboe if (unlikely(ret <= 0)) 1004b92ce558SJens Axboe goto out_release; 1005b92ce558SJens Axboe 1006b92ce558SJens Axboe read_len = ret; 1007c66ab6faSJens Axboe sd->total_len = read_len; 1008b92ce558SJens Axboe 1009b92ce558SJens Axboe /* 1010b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1011b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1012b92ce558SJens Axboe * could get stuck data in the internal pipe: 1013b92ce558SJens Axboe */ 1014c66ab6faSJens Axboe ret = actor(pipe, sd); 1015a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1016a82c53a0STom Zanussi sd->pos = prev_pos; 1017b92ce558SJens Axboe goto out_release; 1018a82c53a0STom Zanussi } 1019b92ce558SJens Axboe 1020b92ce558SJens Axboe bytes += ret; 1021b92ce558SJens Axboe len -= ret; 1022bcd4f3acSJens Axboe sd->pos = pos; 1023b92ce558SJens Axboe 1024a82c53a0STom Zanussi if (ret < read_len) { 1025a82c53a0STom Zanussi sd->pos = prev_pos + ret; 102651a92c0fSJens Axboe goto out_release; 1027b92ce558SJens Axboe } 1028a82c53a0STom Zanussi } 1029b92ce558SJens Axboe 10309e97198dSJens Axboe done: 1031b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10329e97198dSJens Axboe file_accessed(in); 1033b92ce558SJens Axboe return bytes; 1034b92ce558SJens Axboe 1035b92ce558SJens Axboe out_release: 1036b92ce558SJens Axboe /* 1037b92ce558SJens Axboe * If we did an incomplete transfer we must release 1038b92ce558SJens Axboe * the pipe buffers in question: 1039b92ce558SJens Axboe */ 1040b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1041b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1042b92ce558SJens Axboe 1043b92ce558SJens Axboe if (buf->ops) { 1044b92ce558SJens Axboe buf->ops->release(pipe, buf); 1045b92ce558SJens Axboe buf->ops = NULL; 1046b92ce558SJens Axboe } 1047b92ce558SJens Axboe } 1048b92ce558SJens Axboe 10499e97198dSJens Axboe if (!bytes) 10509e97198dSJens Axboe bytes = ret; 1051b92ce558SJens Axboe 10529e97198dSJens Axboe goto done; 1053c66ab6faSJens Axboe } 1054c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1055c66ab6faSJens Axboe 1056c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1057c66ab6faSJens Axboe struct splice_desc *sd) 1058c66ab6faSJens Axboe { 10596a14b90bSJens Axboe struct file *file = sd->u.file; 1060c66ab6faSJens Axboe 1061c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1062c66ab6faSJens Axboe } 1063c66ab6faSJens Axboe 1064932cc6d4SJens Axboe /** 1065932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1066932cc6d4SJens Axboe * @in: file to splice from 1067932cc6d4SJens Axboe * @ppos: input file offset 1068932cc6d4SJens Axboe * @out: file to splice to 1069932cc6d4SJens Axboe * @len: number of bytes to splice 1070932cc6d4SJens Axboe * @flags: splice modifier flags 1071932cc6d4SJens Axboe * 1072932cc6d4SJens Axboe * Description: 1073932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1074932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1075932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1076932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1077932cc6d4SJens Axboe * 1078932cc6d4SJens Axboe */ 1079c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1080c66ab6faSJens Axboe size_t len, unsigned int flags) 1081c66ab6faSJens Axboe { 1082c66ab6faSJens Axboe struct splice_desc sd = { 1083c66ab6faSJens Axboe .len = len, 1084c66ab6faSJens Axboe .total_len = len, 1085c66ab6faSJens Axboe .flags = flags, 1086c66ab6faSJens Axboe .pos = *ppos, 10876a14b90bSJens Axboe .u.file = out, 1088c66ab6faSJens Axboe }; 108951a92c0fSJens Axboe long ret; 1090c66ab6faSJens Axboe 1091c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 109251a92c0fSJens Axboe if (ret > 0) 1093a82c53a0STom Zanussi *ppos = sd.pos; 109451a92c0fSJens Axboe 1095c66ab6faSJens Axboe return ret; 1096b92ce558SJens Axboe } 1097b92ce558SJens Axboe 109883f9135bSJens Axboe /* 1099ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1100ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1101ddac0d39SJens Axboe * pipe. 1102ddac0d39SJens Axboe */ 1103ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1104ddac0d39SJens Axboe { 1105ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1106ddac0d39SJens Axboe return inode->i_pipe; 1107ddac0d39SJens Axboe 1108ddac0d39SJens Axboe return NULL; 1109ddac0d39SJens Axboe } 1110ddac0d39SJens Axboe 1111ddac0d39SJens Axboe /* 111283f9135bSJens Axboe * Determine where to splice to/from. 111383f9135bSJens Axboe */ 1114529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1115529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1116529565dcSIngo Molnar size_t len, unsigned int flags) 11175274f052SJens Axboe { 11183a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1119cbb7e577SJens Axboe loff_t offset, *off; 1120a4514ebdSJens Axboe long ret; 11215274f052SJens Axboe 11220f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1123529565dcSIngo Molnar if (pipe) { 1124529565dcSIngo Molnar if (off_in) 1125529565dcSIngo Molnar return -ESPIPE; 1126b92ce558SJens Axboe if (off_out) { 1127b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1128b92ce558SJens Axboe return -EINVAL; 1129cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1130b92ce558SJens Axboe return -EFAULT; 1131cbb7e577SJens Axboe off = &offset; 1132cbb7e577SJens Axboe } else 1133cbb7e577SJens Axboe off = &out->f_pos; 1134529565dcSIngo Molnar 1135a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1136a4514ebdSJens Axboe 1137a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1138a4514ebdSJens Axboe ret = -EFAULT; 1139a4514ebdSJens Axboe 1140a4514ebdSJens Axboe return ret; 1141529565dcSIngo Molnar } 11425274f052SJens Axboe 11430f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1144529565dcSIngo Molnar if (pipe) { 1145529565dcSIngo Molnar if (off_out) 1146529565dcSIngo Molnar return -ESPIPE; 1147b92ce558SJens Axboe if (off_in) { 1148b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1149b92ce558SJens Axboe return -EINVAL; 1150cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1151b92ce558SJens Axboe return -EFAULT; 1152cbb7e577SJens Axboe off = &offset; 1153cbb7e577SJens Axboe } else 1154cbb7e577SJens Axboe off = &in->f_pos; 1155529565dcSIngo Molnar 1156a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1157a4514ebdSJens Axboe 1158a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1159a4514ebdSJens Axboe ret = -EFAULT; 1160a4514ebdSJens Axboe 1161a4514ebdSJens Axboe return ret; 1162529565dcSIngo Molnar } 11635274f052SJens Axboe 11645274f052SJens Axboe return -EINVAL; 11655274f052SJens Axboe } 11665274f052SJens Axboe 1167912d35f8SJens Axboe /* 1168912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1169912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1170912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1171912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1172912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1173912d35f8SJens Axboe */ 1174912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1175912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 11767afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1177912d35f8SJens Axboe { 1178912d35f8SJens Axboe int buffers = 0, error = 0; 1179912d35f8SJens Axboe 1180912d35f8SJens Axboe while (nr_vecs) { 1181912d35f8SJens Axboe unsigned long off, npages; 118275723957SLinus Torvalds struct iovec entry; 1183912d35f8SJens Axboe void __user *base; 1184912d35f8SJens Axboe size_t len; 1185912d35f8SJens Axboe int i; 1186912d35f8SJens Axboe 118775723957SLinus Torvalds error = -EFAULT; 1188bc40d73cSNick Piggin if (copy_from_user(&entry, iov, sizeof(entry))) 1189912d35f8SJens Axboe break; 119075723957SLinus Torvalds 119175723957SLinus Torvalds base = entry.iov_base; 119275723957SLinus Torvalds len = entry.iov_len; 1193912d35f8SJens Axboe 1194912d35f8SJens Axboe /* 1195912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1196912d35f8SJens Axboe */ 119775723957SLinus Torvalds error = 0; 1198912d35f8SJens Axboe if (unlikely(!len)) 1199912d35f8SJens Axboe break; 1200912d35f8SJens Axboe error = -EFAULT; 1201712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1202912d35f8SJens Axboe break; 1203912d35f8SJens Axboe 1204912d35f8SJens Axboe /* 1205912d35f8SJens Axboe * Get this base offset and number of pages, then map 1206912d35f8SJens Axboe * in the user pages. 1207912d35f8SJens Axboe */ 1208912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12097afa6fd0SJens Axboe 12107afa6fd0SJens Axboe /* 12117afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12127afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12137afa6fd0SJens Axboe */ 12147afa6fd0SJens Axboe error = -EINVAL; 12157afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12167afa6fd0SJens Axboe break; 12177afa6fd0SJens Axboe 1218912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1219912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1220912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1221912d35f8SJens Axboe 1222bc40d73cSNick Piggin error = get_user_pages_fast((unsigned long)base, npages, 1223bc40d73cSNick Piggin 0, &pages[buffers]); 1224912d35f8SJens Axboe 1225912d35f8SJens Axboe if (unlikely(error <= 0)) 1226912d35f8SJens Axboe break; 1227912d35f8SJens Axboe 1228912d35f8SJens Axboe /* 1229912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1230912d35f8SJens Axboe */ 1231912d35f8SJens Axboe for (i = 0; i < error; i++) { 12327591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1233912d35f8SJens Axboe 1234912d35f8SJens Axboe partial[buffers].offset = off; 1235912d35f8SJens Axboe partial[buffers].len = plen; 1236912d35f8SJens Axboe 1237912d35f8SJens Axboe off = 0; 1238912d35f8SJens Axboe len -= plen; 1239912d35f8SJens Axboe buffers++; 1240912d35f8SJens Axboe } 1241912d35f8SJens Axboe 1242912d35f8SJens Axboe /* 1243912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1244912d35f8SJens Axboe * means we have to move some of this into a pipe to 1245912d35f8SJens Axboe * be able to continue. 1246912d35f8SJens Axboe */ 1247912d35f8SJens Axboe if (len) 1248912d35f8SJens Axboe break; 1249912d35f8SJens Axboe 1250912d35f8SJens Axboe /* 1251912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1252912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1253912d35f8SJens Axboe * room for. 1254912d35f8SJens Axboe */ 1255912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1256912d35f8SJens Axboe break; 1257912d35f8SJens Axboe 1258912d35f8SJens Axboe nr_vecs--; 1259912d35f8SJens Axboe iov++; 1260912d35f8SJens Axboe } 1261912d35f8SJens Axboe 1262912d35f8SJens Axboe if (buffers) 1263912d35f8SJens Axboe return buffers; 1264912d35f8SJens Axboe 1265912d35f8SJens Axboe return error; 1266912d35f8SJens Axboe } 1267912d35f8SJens Axboe 12686a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12696a14b90bSJens Axboe struct splice_desc *sd) 12706a14b90bSJens Axboe { 12716a14b90bSJens Axboe char *src; 12726a14b90bSJens Axboe int ret; 12736a14b90bSJens Axboe 1274cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 12756a14b90bSJens Axboe if (unlikely(ret)) 12766a14b90bSJens Axboe return ret; 12776a14b90bSJens Axboe 12786a14b90bSJens Axboe /* 12796a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 12806a14b90bSJens Axboe * pages and doing an atomic copy 12816a14b90bSJens Axboe */ 12826a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 12836a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 12846a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 12856a14b90bSJens Axboe sd->len); 12866a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 12876a14b90bSJens Axboe if (!ret) { 12886a14b90bSJens Axboe ret = sd->len; 12896a14b90bSJens Axboe goto out; 12906a14b90bSJens Axboe } 12916a14b90bSJens Axboe } 12926a14b90bSJens Axboe 12936a14b90bSJens Axboe /* 12946a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 12956a14b90bSJens Axboe */ 12966a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 12976a14b90bSJens Axboe 12986a14b90bSJens Axboe ret = sd->len; 12996a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13006a14b90bSJens Axboe ret = -EFAULT; 13016a14b90bSJens Axboe 13026866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 13036a14b90bSJens Axboe out: 13046a14b90bSJens Axboe if (ret > 0) 13056a14b90bSJens Axboe sd->u.userptr += ret; 13066a14b90bSJens Axboe return ret; 13076a14b90bSJens Axboe } 13086a14b90bSJens Axboe 13096a14b90bSJens Axboe /* 13106a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13116a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13126a14b90bSJens Axboe */ 13136a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13146a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13156a14b90bSJens Axboe { 13166a14b90bSJens Axboe struct pipe_inode_info *pipe; 13176a14b90bSJens Axboe struct splice_desc sd; 13186a14b90bSJens Axboe ssize_t size; 13196a14b90bSJens Axboe int error; 13206a14b90bSJens Axboe long ret; 13216a14b90bSJens Axboe 13226a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13236a14b90bSJens Axboe if (!pipe) 13246a14b90bSJens Axboe return -EBADF; 13256a14b90bSJens Axboe 13266a14b90bSJens Axboe if (pipe->inode) 13276a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13286a14b90bSJens Axboe 13296a14b90bSJens Axboe error = ret = 0; 13306a14b90bSJens Axboe while (nr_segs) { 13316a14b90bSJens Axboe void __user *base; 13326a14b90bSJens Axboe size_t len; 13336a14b90bSJens Axboe 13346a14b90bSJens Axboe /* 13356a14b90bSJens Axboe * Get user address base and length for this iovec. 13366a14b90bSJens Axboe */ 13376a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13386a14b90bSJens Axboe if (unlikely(error)) 13396a14b90bSJens Axboe break; 13406a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13416a14b90bSJens Axboe if (unlikely(error)) 13426a14b90bSJens Axboe break; 13436a14b90bSJens Axboe 13446a14b90bSJens Axboe /* 13456a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13466a14b90bSJens Axboe */ 13476a14b90bSJens Axboe if (unlikely(!len)) 13486a14b90bSJens Axboe break; 13496a14b90bSJens Axboe if (unlikely(!base)) { 13506a14b90bSJens Axboe error = -EFAULT; 13516a14b90bSJens Axboe break; 13526a14b90bSJens Axboe } 13536a14b90bSJens Axboe 13548811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 13558811930dSJens Axboe error = -EFAULT; 13568811930dSJens Axboe break; 13578811930dSJens Axboe } 13588811930dSJens Axboe 13596a14b90bSJens Axboe sd.len = 0; 13606a14b90bSJens Axboe sd.total_len = len; 13616a14b90bSJens Axboe sd.flags = flags; 13626a14b90bSJens Axboe sd.u.userptr = base; 13636a14b90bSJens Axboe sd.pos = 0; 13646a14b90bSJens Axboe 13656a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 13666a14b90bSJens Axboe if (size < 0) { 13676a14b90bSJens Axboe if (!ret) 13686a14b90bSJens Axboe ret = size; 13696a14b90bSJens Axboe 13706a14b90bSJens Axboe break; 13716a14b90bSJens Axboe } 13726a14b90bSJens Axboe 13736a14b90bSJens Axboe ret += size; 13746a14b90bSJens Axboe 13756a14b90bSJens Axboe if (size < len) 13766a14b90bSJens Axboe break; 13776a14b90bSJens Axboe 13786a14b90bSJens Axboe nr_segs--; 13796a14b90bSJens Axboe iov++; 13806a14b90bSJens Axboe } 13816a14b90bSJens Axboe 13826a14b90bSJens Axboe if (pipe->inode) 13836a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 13846a14b90bSJens Axboe 13856a14b90bSJens Axboe if (!ret) 13866a14b90bSJens Axboe ret = error; 13876a14b90bSJens Axboe 13886a14b90bSJens Axboe return ret; 13896a14b90bSJens Axboe } 13906a14b90bSJens Axboe 1391912d35f8SJens Axboe /* 1392912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1393912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1394912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1395912d35f8SJens Axboe */ 13966a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1397912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1398912d35f8SJens Axboe { 1399ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1400912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1401912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1402912d35f8SJens Axboe struct splice_pipe_desc spd = { 1403912d35f8SJens Axboe .pages = pages, 1404912d35f8SJens Axboe .partial = partial, 1405912d35f8SJens Axboe .flags = flags, 1406912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1407bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1408912d35f8SJens Axboe }; 1409912d35f8SJens Axboe 14100f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1411ddac0d39SJens Axboe if (!pipe) 1412912d35f8SJens Axboe return -EBADF; 1413912d35f8SJens Axboe 14147afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14157afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1416912d35f8SJens Axboe if (spd.nr_pages <= 0) 1417912d35f8SJens Axboe return spd.nr_pages; 1418912d35f8SJens Axboe 141900522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1420912d35f8SJens Axboe } 1421912d35f8SJens Axboe 14226a14b90bSJens Axboe /* 14236a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14246a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14256a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14266a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14276a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14286a14b90bSJens Axboe * solutions for that: 14296a14b90bSJens Axboe * 14306a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14316a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14326a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14336a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14346a14b90bSJens Axboe * 14356a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14366a14b90bSJens Axboe * 14376a14b90bSJens Axboe */ 1438912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1439912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1440912d35f8SJens Axboe { 1441912d35f8SJens Axboe struct file *file; 1442912d35f8SJens Axboe long error; 1443912d35f8SJens Axboe int fput; 1444912d35f8SJens Axboe 14456a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14466a14b90bSJens Axboe return -EINVAL; 14476a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14486a14b90bSJens Axboe return 0; 14496a14b90bSJens Axboe 1450912d35f8SJens Axboe error = -EBADF; 1451912d35f8SJens Axboe file = fget_light(fd, &fput); 1452912d35f8SJens Axboe if (file) { 1453912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14546a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14556a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14566a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1457912d35f8SJens Axboe 1458912d35f8SJens Axboe fput_light(file, fput); 1459912d35f8SJens Axboe } 1460912d35f8SJens Axboe 1461912d35f8SJens Axboe return error; 1462912d35f8SJens Axboe } 1463912d35f8SJens Axboe 1464529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1465529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1466529565dcSIngo Molnar size_t len, unsigned int flags) 14675274f052SJens Axboe { 14685274f052SJens Axboe long error; 14695274f052SJens Axboe struct file *in, *out; 14705274f052SJens Axboe int fput_in, fput_out; 14715274f052SJens Axboe 14725274f052SJens Axboe if (unlikely(!len)) 14735274f052SJens Axboe return 0; 14745274f052SJens Axboe 14755274f052SJens Axboe error = -EBADF; 1476529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 14775274f052SJens Axboe if (in) { 14785274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1479529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 14805274f052SJens Axboe if (out) { 14815274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1482529565dcSIngo Molnar error = do_splice(in, off_in, 1483529565dcSIngo Molnar out, off_out, 1484529565dcSIngo Molnar len, flags); 14855274f052SJens Axboe fput_light(out, fput_out); 14865274f052SJens Axboe } 14875274f052SJens Axboe } 14885274f052SJens Axboe 14895274f052SJens Axboe fput_light(in, fput_in); 14905274f052SJens Axboe } 14915274f052SJens Axboe 14925274f052SJens Axboe return error; 14935274f052SJens Axboe } 149470524490SJens Axboe 149570524490SJens Axboe /* 1496aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1497aadd06e5SJens Axboe * return an appropriate error. 1498aadd06e5SJens Axboe */ 1499aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1500aadd06e5SJens Axboe { 1501aadd06e5SJens Axboe int ret; 1502aadd06e5SJens Axboe 1503aadd06e5SJens Axboe /* 1504aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1505aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1506aadd06e5SJens Axboe */ 1507aadd06e5SJens Axboe if (pipe->nrbufs) 1508aadd06e5SJens Axboe return 0; 1509aadd06e5SJens Axboe 1510aadd06e5SJens Axboe ret = 0; 1511aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1512aadd06e5SJens Axboe 1513aadd06e5SJens Axboe while (!pipe->nrbufs) { 1514aadd06e5SJens Axboe if (signal_pending(current)) { 1515aadd06e5SJens Axboe ret = -ERESTARTSYS; 1516aadd06e5SJens Axboe break; 1517aadd06e5SJens Axboe } 1518aadd06e5SJens Axboe if (!pipe->writers) 1519aadd06e5SJens Axboe break; 1520aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1521aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1522aadd06e5SJens Axboe ret = -EAGAIN; 1523aadd06e5SJens Axboe break; 1524aadd06e5SJens Axboe } 1525aadd06e5SJens Axboe } 1526aadd06e5SJens Axboe pipe_wait(pipe); 1527aadd06e5SJens Axboe } 1528aadd06e5SJens Axboe 1529aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1530aadd06e5SJens Axboe return ret; 1531aadd06e5SJens Axboe } 1532aadd06e5SJens Axboe 1533aadd06e5SJens Axboe /* 1534aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1535aadd06e5SJens Axboe * return an appropriate error. 1536aadd06e5SJens Axboe */ 1537aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1538aadd06e5SJens Axboe { 1539aadd06e5SJens Axboe int ret; 1540aadd06e5SJens Axboe 1541aadd06e5SJens Axboe /* 1542aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1543aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1544aadd06e5SJens Axboe */ 1545aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1546aadd06e5SJens Axboe return 0; 1547aadd06e5SJens Axboe 1548aadd06e5SJens Axboe ret = 0; 1549aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1550aadd06e5SJens Axboe 1551aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1552aadd06e5SJens Axboe if (!pipe->readers) { 1553aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1554aadd06e5SJens Axboe ret = -EPIPE; 1555aadd06e5SJens Axboe break; 1556aadd06e5SJens Axboe } 1557aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1558aadd06e5SJens Axboe ret = -EAGAIN; 1559aadd06e5SJens Axboe break; 1560aadd06e5SJens Axboe } 1561aadd06e5SJens Axboe if (signal_pending(current)) { 1562aadd06e5SJens Axboe ret = -ERESTARTSYS; 1563aadd06e5SJens Axboe break; 1564aadd06e5SJens Axboe } 1565aadd06e5SJens Axboe pipe->waiting_writers++; 1566aadd06e5SJens Axboe pipe_wait(pipe); 1567aadd06e5SJens Axboe pipe->waiting_writers--; 1568aadd06e5SJens Axboe } 1569aadd06e5SJens Axboe 1570aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1571aadd06e5SJens Axboe return ret; 1572aadd06e5SJens Axboe } 1573aadd06e5SJens Axboe 1574aadd06e5SJens Axboe /* 157570524490SJens Axboe * Link contents of ipipe to opipe. 157670524490SJens Axboe */ 157770524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 157870524490SJens Axboe struct pipe_inode_info *opipe, 157970524490SJens Axboe size_t len, unsigned int flags) 158070524490SJens Axboe { 158170524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1582aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 158370524490SJens Axboe 158470524490SJens Axboe /* 158570524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 158670524490SJens Axboe * grabbing by inode address. Otherwise two different processes 158770524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 158870524490SJens Axboe */ 158962752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 159070524490SJens Axboe 1591aadd06e5SJens Axboe do { 159270524490SJens Axboe if (!opipe->readers) { 159370524490SJens Axboe send_sig(SIGPIPE, current, 0); 159470524490SJens Axboe if (!ret) 159570524490SJens Axboe ret = -EPIPE; 159670524490SJens Axboe break; 159770524490SJens Axboe } 159870524490SJens Axboe 159970524490SJens Axboe /* 1600aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1601aadd06e5SJens Axboe * output room, break. 160270524490SJens Axboe */ 1603aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1604aadd06e5SJens Axboe break; 1605aadd06e5SJens Axboe 1606aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1607aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 160870524490SJens Axboe 160970524490SJens Axboe /* 161070524490SJens Axboe * Get a reference to this pipe buffer, 161170524490SJens Axboe * so we can copy the contents over. 161270524490SJens Axboe */ 161370524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 161470524490SJens Axboe 161570524490SJens Axboe obuf = opipe->bufs + nbuf; 161670524490SJens Axboe *obuf = *ibuf; 161770524490SJens Axboe 16187afa6fd0SJens Axboe /* 16197afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16207afa6fd0SJens Axboe * prevent multiple steals of this page. 16217afa6fd0SJens Axboe */ 16227afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16237afa6fd0SJens Axboe 162470524490SJens Axboe if (obuf->len > len) 162570524490SJens Axboe obuf->len = len; 162670524490SJens Axboe 162770524490SJens Axboe opipe->nrbufs++; 162870524490SJens Axboe ret += obuf->len; 162970524490SJens Axboe len -= obuf->len; 1630aadd06e5SJens Axboe i++; 1631aadd06e5SJens Axboe } while (len); 163270524490SJens Axboe 163302cf01aeSJens Axboe /* 163402cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 163502cf01aeSJens Axboe * future, otherwise just return 0 163602cf01aeSJens Axboe */ 163702cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 163802cf01aeSJens Axboe ret = -EAGAIN; 163902cf01aeSJens Axboe 164062752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 164170524490SJens Axboe 1642aadd06e5SJens Axboe /* 1643aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1644aadd06e5SJens Axboe */ 1645aadd06e5SJens Axboe if (ret > 0) { 164670524490SJens Axboe smp_mb(); 164770524490SJens Axboe if (waitqueue_active(&opipe->wait)) 164870524490SJens Axboe wake_up_interruptible(&opipe->wait); 164970524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 165070524490SJens Axboe } 165170524490SJens Axboe 165270524490SJens Axboe return ret; 165370524490SJens Axboe } 165470524490SJens Axboe 165570524490SJens Axboe /* 165670524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 165770524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 165870524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 165970524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 166070524490SJens Axboe */ 166170524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 166270524490SJens Axboe unsigned int flags) 166370524490SJens Axboe { 16640f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 16650f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1666aadd06e5SJens Axboe int ret = -EINVAL; 166770524490SJens Axboe 166870524490SJens Axboe /* 1669aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1670aadd06e5SJens Axboe * copying the data. 167170524490SJens Axboe */ 1672aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1673aadd06e5SJens Axboe /* 1674aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1675aadd06e5SJens Axboe * ordering doesn't really matter. 1676aadd06e5SJens Axboe */ 1677aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1678aadd06e5SJens Axboe if (!ret) { 1679aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 168002cf01aeSJens Axboe if (!ret) 1681aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1682aadd06e5SJens Axboe } 1683aadd06e5SJens Axboe } 168470524490SJens Axboe 1685aadd06e5SJens Axboe return ret; 168670524490SJens Axboe } 168770524490SJens Axboe 168870524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 168970524490SJens Axboe { 169070524490SJens Axboe struct file *in; 169170524490SJens Axboe int error, fput_in; 169270524490SJens Axboe 169370524490SJens Axboe if (unlikely(!len)) 169470524490SJens Axboe return 0; 169570524490SJens Axboe 169670524490SJens Axboe error = -EBADF; 169770524490SJens Axboe in = fget_light(fdin, &fput_in); 169870524490SJens Axboe if (in) { 169970524490SJens Axboe if (in->f_mode & FMODE_READ) { 170070524490SJens Axboe int fput_out; 170170524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 170270524490SJens Axboe 170370524490SJens Axboe if (out) { 170470524490SJens Axboe if (out->f_mode & FMODE_WRITE) 170570524490SJens Axboe error = do_tee(in, out, len, flags); 170670524490SJens Axboe fput_light(out, fput_out); 170770524490SJens Axboe } 170870524490SJens Axboe } 170970524490SJens Axboe fput_light(in, fput_in); 171070524490SJens Axboe } 171170524490SJens Axboe 171270524490SJens Axboe return error; 171370524490SJens Axboe } 1714