15274f052SJens Axboe /* 25274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 35274f052SJens Axboe * 45274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 55274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 65274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 75274f052SJens Axboe * 85274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 95274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 105274f052SJens Axboe * 115274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 12c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 13c2058e06SJens Axboe * fixing lots of bugs. 145274f052SJens Axboe * 150fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 16c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 17c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 185274f052SJens Axboe * 195274f052SJens Axboe */ 205274f052SJens Axboe #include <linux/fs.h> 215274f052SJens Axboe #include <linux/file.h> 225274f052SJens Axboe #include <linux/pagemap.h> 23d6b29d7cSJens Axboe #include <linux/splice.h> 245274f052SJens Axboe #include <linux/mm_inline.h> 255abc97aaSJens Axboe #include <linux/swap.h> 264f6f0bd2SJens Axboe #include <linux/writeback.h> 274f6f0bd2SJens Axboe #include <linux/buffer_head.h> 28a0f06780SJeff Garzik #include <linux/module.h> 294f6f0bd2SJens Axboe #include <linux/syscalls.h> 30912d35f8SJens Axboe #include <linux/uio.h> 3129ce2058SJames Morris #include <linux/security.h> 325274f052SJens Axboe 3383f9135bSJens Axboe /* 3483f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3583f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 3683f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 3783f9135bSJens Axboe * attempt to reuse this page for another destination. 3883f9135bSJens Axboe */ 3976ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 405abc97aaSJens Axboe struct pipe_buffer *buf) 415abc97aaSJens Axboe { 425abc97aaSJens Axboe struct page *page = buf->page; 439e94cd4fSJens Axboe struct address_space *mapping; 445abc97aaSJens Axboe 459e0267c2SJens Axboe lock_page(page); 469e0267c2SJens Axboe 479e94cd4fSJens Axboe mapping = page_mapping(page); 489e94cd4fSJens Axboe if (mapping) { 495abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 505abc97aaSJens Axboe 51ad8d6f0aSJens Axboe /* 529e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 539e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 549e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 559e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 569e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 579e94cd4fSJens Axboe * ensues. 58ad8d6f0aSJens Axboe */ 59ad8d6f0aSJens Axboe wait_on_page_writeback(page); 60ad8d6f0aSJens Axboe 61ca39d651SJens Axboe if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) 62ca39d651SJens Axboe goto out_unlock; 634f6f0bd2SJens Axboe 649e94cd4fSJens Axboe /* 659e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 669e94cd4fSJens Axboe * and return good. 679e94cd4fSJens Axboe */ 689e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 691432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 705abc97aaSJens Axboe return 0; 715abc97aaSJens Axboe } 729e94cd4fSJens Axboe } 739e94cd4fSJens Axboe 749e94cd4fSJens Axboe /* 759e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 769e94cd4fSJens Axboe * address space, unlock and return failure. 779e94cd4fSJens Axboe */ 78ca39d651SJens Axboe out_unlock: 799e94cd4fSJens Axboe unlock_page(page); 809e94cd4fSJens Axboe return 1; 819e94cd4fSJens Axboe } 825abc97aaSJens Axboe 8376ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 845274f052SJens Axboe struct pipe_buffer *buf) 855274f052SJens Axboe { 865274f052SJens Axboe page_cache_release(buf->page); 871432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 885274f052SJens Axboe } 895274f052SJens Axboe 900845718dSJens Axboe /* 910845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 920845718dSJens Axboe * is a page cache page, IO may be in flight. 930845718dSJens Axboe */ 94cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 955274f052SJens Axboe struct pipe_buffer *buf) 965274f052SJens Axboe { 975274f052SJens Axboe struct page *page = buf->page; 9849d0b21bSJens Axboe int err; 995274f052SJens Axboe 1005274f052SJens Axboe if (!PageUptodate(page)) { 10149d0b21bSJens Axboe lock_page(page); 1025274f052SJens Axboe 10349d0b21bSJens Axboe /* 10449d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10573d62d83SIngo Molnar * splice, if this is the first page. 10649d0b21bSJens Axboe */ 1075274f052SJens Axboe if (!page->mapping) { 10849d0b21bSJens Axboe err = -ENODATA; 10949d0b21bSJens Axboe goto error; 1105274f052SJens Axboe } 1115274f052SJens Axboe 11249d0b21bSJens Axboe /* 11373d62d83SIngo Molnar * Uh oh, read-error from disk. 11449d0b21bSJens Axboe */ 11549d0b21bSJens Axboe if (!PageUptodate(page)) { 11649d0b21bSJens Axboe err = -EIO; 11749d0b21bSJens Axboe goto error; 11849d0b21bSJens Axboe } 11949d0b21bSJens Axboe 12049d0b21bSJens Axboe /* 121f84d7519SJens Axboe * Page is ok afterall, we are done. 12249d0b21bSJens Axboe */ 12349d0b21bSJens Axboe unlock_page(page); 12449d0b21bSJens Axboe } 12549d0b21bSJens Axboe 126f84d7519SJens Axboe return 0; 12749d0b21bSJens Axboe error: 12849d0b21bSJens Axboe unlock_page(page); 129f84d7519SJens Axboe return err; 13070524490SJens Axboe } 13170524490SJens Axboe 132d4c3cca9SEric Dumazet static const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1335274f052SJens Axboe .can_merge = 0, 134f84d7519SJens Axboe .map = generic_pipe_buf_map, 135f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 136cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1375274f052SJens Axboe .release = page_cache_pipe_buf_release, 1385abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 139f84d7519SJens Axboe .get = generic_pipe_buf_get, 1405274f052SJens Axboe }; 1415274f052SJens Axboe 142912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 143912d35f8SJens Axboe struct pipe_buffer *buf) 144912d35f8SJens Axboe { 1457afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 146912d35f8SJens Axboe return 1; 1477afa6fd0SJens Axboe 1481432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 149330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 150912d35f8SJens Axboe } 151912d35f8SJens Axboe 152d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 153912d35f8SJens Axboe .can_merge = 0, 154f84d7519SJens Axboe .map = generic_pipe_buf_map, 155f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 156cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 157912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 158912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 159f84d7519SJens Axboe .get = generic_pipe_buf_get, 160912d35f8SJens Axboe }; 161912d35f8SJens Axboe 162932cc6d4SJens Axboe /** 163932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 164932cc6d4SJens Axboe * @pipe: pipe to fill 165932cc6d4SJens Axboe * @spd: data to fill 166932cc6d4SJens Axboe * 167932cc6d4SJens Axboe * Description: 16879685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 169932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 170932cc6d4SJens Axboe * function will link that data to the pipe. 171932cc6d4SJens Axboe * 17283f9135bSJens Axboe */ 173d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 174912d35f8SJens Axboe struct splice_pipe_desc *spd) 1755274f052SJens Axboe { 17600de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 177912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1785274f052SJens Axboe 1795274f052SJens Axboe ret = 0; 1805274f052SJens Axboe do_wakeup = 0; 181912d35f8SJens Axboe page_nr = 0; 1825274f052SJens Axboe 1833a326a2cSIngo Molnar if (pipe->inode) 1843a326a2cSIngo Molnar mutex_lock(&pipe->inode->i_mutex); 1855274f052SJens Axboe 1865274f052SJens Axboe for (;;) { 1873a326a2cSIngo Molnar if (!pipe->readers) { 1885274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1895274f052SJens Axboe if (!ret) 1905274f052SJens Axboe ret = -EPIPE; 1915274f052SJens Axboe break; 1925274f052SJens Axboe } 1935274f052SJens Axboe 1946f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) { 1956f767b04SJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); 1963a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 1975274f052SJens Axboe 198912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 199912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 200912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 201497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 202912d35f8SJens Axboe buf->ops = spd->ops; 2037afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2047afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2057afa6fd0SJens Axboe 2066f767b04SJens Axboe pipe->nrbufs++; 207912d35f8SJens Axboe page_nr++; 208912d35f8SJens Axboe ret += buf->len; 209912d35f8SJens Axboe 2106f767b04SJens Axboe if (pipe->inode) 2115274f052SJens Axboe do_wakeup = 1; 2125274f052SJens Axboe 213912d35f8SJens Axboe if (!--spd->nr_pages) 2145274f052SJens Axboe break; 2156f767b04SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 2165274f052SJens Axboe continue; 2175274f052SJens Axboe 2185274f052SJens Axboe break; 2195274f052SJens Axboe } 2205274f052SJens Axboe 221912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 22229e35094SLinus Torvalds if (!ret) 22329e35094SLinus Torvalds ret = -EAGAIN; 22429e35094SLinus Torvalds break; 22529e35094SLinus Torvalds } 22629e35094SLinus Torvalds 2275274f052SJens Axboe if (signal_pending(current)) { 2285274f052SJens Axboe if (!ret) 2295274f052SJens Axboe ret = -ERESTARTSYS; 2305274f052SJens Axboe break; 2315274f052SJens Axboe } 2325274f052SJens Axboe 2335274f052SJens Axboe if (do_wakeup) { 234c0bd1f65SJens Axboe smp_mb(); 2353a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2363a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2373a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2385274f052SJens Axboe do_wakeup = 0; 2395274f052SJens Axboe } 2405274f052SJens Axboe 2413a326a2cSIngo Molnar pipe->waiting_writers++; 2423a326a2cSIngo Molnar pipe_wait(pipe); 2433a326a2cSIngo Molnar pipe->waiting_writers--; 2445274f052SJens Axboe } 2455274f052SJens Axboe 24602676e5aSJens Axboe if (pipe->inode) { 2473a326a2cSIngo Molnar mutex_unlock(&pipe->inode->i_mutex); 2485274f052SJens Axboe 2495274f052SJens Axboe if (do_wakeup) { 250c0bd1f65SJens Axboe smp_mb(); 2513a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2523a326a2cSIngo Molnar wake_up_interruptible(&pipe->wait); 2533a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2545274f052SJens Axboe } 25502676e5aSJens Axboe } 2565274f052SJens Axboe 25700de00bdSJens Axboe while (page_nr < spd_pages) 258bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2595274f052SJens Axboe 2605274f052SJens Axboe return ret; 2615274f052SJens Axboe } 2625274f052SJens Axboe 263bbdfc2f7SJens Axboe static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 264bbdfc2f7SJens Axboe { 265bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 266bbdfc2f7SJens Axboe } 267bbdfc2f7SJens Axboe 2683a326a2cSIngo Molnar static int 269cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 270cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 271cbb7e577SJens Axboe unsigned int flags) 2725274f052SJens Axboe { 2735274f052SJens Axboe struct address_space *mapping = in->f_mapping; 274d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 27516c523ddSJens Axboe struct page *pages[PIPE_BUFFERS]; 276912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 2775274f052SJens Axboe struct page *page; 27891ad66efSJens Axboe pgoff_t index, end_index; 27991ad66efSJens Axboe loff_t isize; 280eb20796bSJens Axboe int error, page_nr; 281912d35f8SJens Axboe struct splice_pipe_desc spd = { 282912d35f8SJens Axboe .pages = pages, 283912d35f8SJens Axboe .partial = partial, 284912d35f8SJens Axboe .flags = flags, 285912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 286bbdfc2f7SJens Axboe .spd_release = spd_release_page, 287912d35f8SJens Axboe }; 2885274f052SJens Axboe 289cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 290912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 291d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 292d8983910SFengguang Wu nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); 2935274f052SJens Axboe 2945274f052SJens Axboe /* 295eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 29682aa5d61SJens Axboe */ 297eb20796bSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); 298431a4820SFengguang Wu index += spd.nr_pages; 299eb20796bSJens Axboe 3005274f052SJens Axboe /* 301eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 302431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 303eb20796bSJens Axboe */ 304431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 305cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 306cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 307431a4820SFengguang Wu 308932cc6d4SJens Axboe error = 0; 309eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 310eb20796bSJens Axboe /* 311eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 312eb20796bSJens Axboe * the first hole. 3135274f052SJens Axboe */ 3147480a904SJens Axboe page = find_get_page(mapping, index); 3157480a904SJens Axboe if (!page) { 316e27dedd8SJens Axboe /* 317eb20796bSJens Axboe * page didn't exist, allocate one. 3187480a904SJens Axboe */ 3197480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3205274f052SJens Axboe if (!page) 3215274f052SJens Axboe break; 3225274f052SJens Axboe 3237480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3244cd13504SHugh Dickins mapping_gfp_mask(mapping)); 3255274f052SJens Axboe if (unlikely(error)) { 3265274f052SJens Axboe page_cache_release(page); 327a0548871SJens Axboe if (error == -EEXIST) 328a0548871SJens Axboe continue; 3295274f052SJens Axboe break; 3305274f052SJens Axboe } 331eb20796bSJens Axboe /* 332eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 333eb20796bSJens Axboe * to avoid convoluting the logic below even more. 334eb20796bSJens Axboe */ 335eb20796bSJens Axboe unlock_page(page); 3365274f052SJens Axboe } 3377480a904SJens Axboe 338eb20796bSJens Axboe pages[spd.nr_pages++] = page; 339eb20796bSJens Axboe index++; 340eb20796bSJens Axboe } 341eb20796bSJens Axboe 342eb20796bSJens Axboe /* 343eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 344eb20796bSJens Axboe * pages, fill in the partial map, etc. 345eb20796bSJens Axboe */ 346eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 347eb20796bSJens Axboe nr_pages = spd.nr_pages; 348eb20796bSJens Axboe spd.nr_pages = 0; 349eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 350eb20796bSJens Axboe unsigned int this_len; 351eb20796bSJens Axboe 352eb20796bSJens Axboe if (!len) 353eb20796bSJens Axboe break; 354eb20796bSJens Axboe 355eb20796bSJens Axboe /* 356eb20796bSJens Axboe * this_len is the max we'll use from this page 357eb20796bSJens Axboe */ 358eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 359eb20796bSJens Axboe page = pages[page_nr]; 360eb20796bSJens Axboe 361a08a166fSFengguang Wu if (PageReadahead(page)) 362cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 363d8983910SFengguang Wu page, index, req_pages - page_nr); 364a08a166fSFengguang Wu 3657480a904SJens Axboe /* 3667480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 3677480a904SJens Axboe */ 3687480a904SJens Axboe if (!PageUptodate(page)) { 369c4f895cbSJens Axboe /* 370c4f895cbSJens Axboe * If in nonblock mode then dont block on waiting 371c4f895cbSJens Axboe * for an in-flight io page 372c4f895cbSJens Axboe */ 3739ae9d68cSFengguang Wu if (flags & SPLICE_F_NONBLOCK) { 3748191ecd1SJens Axboe if (TestSetPageLocked(page)) { 3758191ecd1SJens Axboe error = -EAGAIN; 376c4f895cbSJens Axboe break; 3778191ecd1SJens Axboe } 3789ae9d68cSFengguang Wu } else 3797480a904SJens Axboe lock_page(page); 3807480a904SJens Axboe 3817480a904SJens Axboe /* 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 7750f7fc9e4SJosef "Jeff" Sipek err = remove_suid(out->f_path.dentry); 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); 8337f3d4ee1SMiklos Szeredi ret = remove_suid(out->f_path.dentry); 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 901cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 9025274f052SJens Axboe if (unlikely(ret < 0)) 9035274f052SJens Axboe return ret; 9045274f052SJens Axboe 905cbb7e577SJens Axboe return out->f_op->splice_write(pipe, out, ppos, len, flags); 9065274f052SJens Axboe } 9075274f052SJens Axboe 90883f9135bSJens Axboe /* 90983f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 91083f9135bSJens Axboe */ 911cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 912cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 913cbb7e577SJens Axboe unsigned int flags) 9145274f052SJens Axboe { 9155274f052SJens Axboe int ret; 9165274f052SJens Axboe 91749570e9bSJens Axboe if (unlikely(!in->f_op || !in->f_op->splice_read)) 9185274f052SJens Axboe return -EINVAL; 9195274f052SJens Axboe 92049570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 9215274f052SJens Axboe return -EBADF; 9225274f052SJens Axboe 923cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9245274f052SJens Axboe if (unlikely(ret < 0)) 9255274f052SJens Axboe return ret; 9265274f052SJens Axboe 927cbb7e577SJens Axboe return in->f_op->splice_read(in, ppos, pipe, len, flags); 9285274f052SJens Axboe } 9295274f052SJens Axboe 930932cc6d4SJens Axboe /** 931932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 932932cc6d4SJens Axboe * @in: file to splice from 933932cc6d4SJens Axboe * @sd: actor information on where to splice to 934932cc6d4SJens Axboe * @actor: handles the data splicing 935932cc6d4SJens Axboe * 936932cc6d4SJens Axboe * Description: 937932cc6d4SJens Axboe * This is a special case helper to splice directly between two 938932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 939932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 940932cc6d4SJens Axboe * that process. 941932cc6d4SJens Axboe * 942c66ab6faSJens Axboe */ 943c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 944c66ab6faSJens Axboe splice_direct_actor *actor) 945b92ce558SJens Axboe { 946b92ce558SJens Axboe struct pipe_inode_info *pipe; 947b92ce558SJens Axboe long ret, bytes; 948b92ce558SJens Axboe umode_t i_mode; 949c66ab6faSJens Axboe size_t len; 950c66ab6faSJens Axboe int i, flags; 951b92ce558SJens Axboe 952b92ce558SJens Axboe /* 953b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 954b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 955b92ce558SJens Axboe * piped splicing for that! 956b92ce558SJens Axboe */ 9570f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 958b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 959b92ce558SJens Axboe return -EINVAL; 960b92ce558SJens Axboe 961b92ce558SJens Axboe /* 962b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 963b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 964b92ce558SJens Axboe */ 965b92ce558SJens Axboe pipe = current->splice_pipe; 96649570e9bSJens Axboe if (unlikely(!pipe)) { 967b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 968b92ce558SJens Axboe if (!pipe) 969b92ce558SJens Axboe return -ENOMEM; 970b92ce558SJens Axboe 971b92ce558SJens Axboe /* 972b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 97300522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 974b92ce558SJens Axboe * PIPE_READERS appropriately. 975b92ce558SJens Axboe */ 976b92ce558SJens Axboe pipe->readers = 1; 977b92ce558SJens Axboe 978b92ce558SJens Axboe current->splice_pipe = pipe; 979b92ce558SJens Axboe } 980b92ce558SJens Axboe 981b92ce558SJens Axboe /* 98273d62d83SIngo Molnar * Do the splice. 983b92ce558SJens Axboe */ 984b92ce558SJens Axboe ret = 0; 985b92ce558SJens Axboe bytes = 0; 986c66ab6faSJens Axboe len = sd->total_len; 987c66ab6faSJens Axboe flags = sd->flags; 988c66ab6faSJens Axboe 989c66ab6faSJens Axboe /* 990c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 991c66ab6faSJens Axboe */ 992c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 993b92ce558SJens Axboe 994b92ce558SJens Axboe while (len) { 99551a92c0fSJens Axboe size_t read_len; 996a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 997b92ce558SJens Axboe 998bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 99951a92c0fSJens Axboe if (unlikely(ret <= 0)) 1000b92ce558SJens Axboe goto out_release; 1001b92ce558SJens Axboe 1002b92ce558SJens Axboe read_len = ret; 1003c66ab6faSJens Axboe sd->total_len = read_len; 1004b92ce558SJens Axboe 1005b92ce558SJens Axboe /* 1006b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1007b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1008b92ce558SJens Axboe * could get stuck data in the internal pipe: 1009b92ce558SJens Axboe */ 1010c66ab6faSJens Axboe ret = actor(pipe, sd); 1011a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1012a82c53a0STom Zanussi sd->pos = prev_pos; 1013b92ce558SJens Axboe goto out_release; 1014a82c53a0STom Zanussi } 1015b92ce558SJens Axboe 1016b92ce558SJens Axboe bytes += ret; 1017b92ce558SJens Axboe len -= ret; 1018bcd4f3acSJens Axboe sd->pos = pos; 1019b92ce558SJens Axboe 1020a82c53a0STom Zanussi if (ret < read_len) { 1021a82c53a0STom Zanussi sd->pos = prev_pos + ret; 102251a92c0fSJens Axboe goto out_release; 1023b92ce558SJens Axboe } 1024a82c53a0STom Zanussi } 1025b92ce558SJens Axboe 10269e97198dSJens Axboe done: 1027b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10289e97198dSJens Axboe file_accessed(in); 1029b92ce558SJens Axboe return bytes; 1030b92ce558SJens Axboe 1031b92ce558SJens Axboe out_release: 1032b92ce558SJens Axboe /* 1033b92ce558SJens Axboe * If we did an incomplete transfer we must release 1034b92ce558SJens Axboe * the pipe buffers in question: 1035b92ce558SJens Axboe */ 1036b92ce558SJens Axboe for (i = 0; i < PIPE_BUFFERS; i++) { 1037b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1038b92ce558SJens Axboe 1039b92ce558SJens Axboe if (buf->ops) { 1040b92ce558SJens Axboe buf->ops->release(pipe, buf); 1041b92ce558SJens Axboe buf->ops = NULL; 1042b92ce558SJens Axboe } 1043b92ce558SJens Axboe } 1044b92ce558SJens Axboe 10459e97198dSJens Axboe if (!bytes) 10469e97198dSJens Axboe bytes = ret; 1047b92ce558SJens Axboe 10489e97198dSJens Axboe goto done; 1049c66ab6faSJens Axboe } 1050c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1051c66ab6faSJens Axboe 1052c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1053c66ab6faSJens Axboe struct splice_desc *sd) 1054c66ab6faSJens Axboe { 10556a14b90bSJens Axboe struct file *file = sd->u.file; 1056c66ab6faSJens Axboe 1057c66ab6faSJens Axboe return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); 1058c66ab6faSJens Axboe } 1059c66ab6faSJens Axboe 1060932cc6d4SJens Axboe /** 1061932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1062932cc6d4SJens Axboe * @in: file to splice from 1063932cc6d4SJens Axboe * @ppos: input file offset 1064932cc6d4SJens Axboe * @out: file to splice to 1065932cc6d4SJens Axboe * @len: number of bytes to splice 1066932cc6d4SJens Axboe * @flags: splice modifier flags 1067932cc6d4SJens Axboe * 1068932cc6d4SJens Axboe * Description: 1069932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1070932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1071932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1072932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1073932cc6d4SJens Axboe * 1074932cc6d4SJens Axboe */ 1075c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1076c66ab6faSJens Axboe size_t len, unsigned int flags) 1077c66ab6faSJens Axboe { 1078c66ab6faSJens Axboe struct splice_desc sd = { 1079c66ab6faSJens Axboe .len = len, 1080c66ab6faSJens Axboe .total_len = len, 1081c66ab6faSJens Axboe .flags = flags, 1082c66ab6faSJens Axboe .pos = *ppos, 10836a14b90bSJens Axboe .u.file = out, 1084c66ab6faSJens Axboe }; 108551a92c0fSJens Axboe long ret; 1086c66ab6faSJens Axboe 1087c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 108851a92c0fSJens Axboe if (ret > 0) 1089a82c53a0STom Zanussi *ppos = sd.pos; 109051a92c0fSJens Axboe 1091c66ab6faSJens Axboe return ret; 1092b92ce558SJens Axboe } 1093b92ce558SJens Axboe 109483f9135bSJens Axboe /* 1095ddac0d39SJens Axboe * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same 1096ddac0d39SJens Axboe * location, so checking ->i_pipe is not enough to verify that this is a 1097ddac0d39SJens Axboe * pipe. 1098ddac0d39SJens Axboe */ 1099ddac0d39SJens Axboe static inline struct pipe_inode_info *pipe_info(struct inode *inode) 1100ddac0d39SJens Axboe { 1101ddac0d39SJens Axboe if (S_ISFIFO(inode->i_mode)) 1102ddac0d39SJens Axboe return inode->i_pipe; 1103ddac0d39SJens Axboe 1104ddac0d39SJens Axboe return NULL; 1105ddac0d39SJens Axboe } 1106ddac0d39SJens Axboe 1107ddac0d39SJens Axboe /* 110883f9135bSJens Axboe * Determine where to splice to/from. 110983f9135bSJens Axboe */ 1110529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1111529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1112529565dcSIngo Molnar size_t len, unsigned int flags) 11135274f052SJens Axboe { 11143a326a2cSIngo Molnar struct pipe_inode_info *pipe; 1115cbb7e577SJens Axboe loff_t offset, *off; 1116a4514ebdSJens Axboe long ret; 11175274f052SJens Axboe 11180f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(in->f_path.dentry->d_inode); 1119529565dcSIngo Molnar if (pipe) { 1120529565dcSIngo Molnar if (off_in) 1121529565dcSIngo Molnar return -ESPIPE; 1122b92ce558SJens Axboe if (off_out) { 1123b92ce558SJens Axboe if (out->f_op->llseek == no_llseek) 1124b92ce558SJens Axboe return -EINVAL; 1125cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1126b92ce558SJens Axboe return -EFAULT; 1127cbb7e577SJens Axboe off = &offset; 1128cbb7e577SJens Axboe } else 1129cbb7e577SJens Axboe off = &out->f_pos; 1130529565dcSIngo Molnar 1131a4514ebdSJens Axboe ret = do_splice_from(pipe, out, off, len, flags); 1132a4514ebdSJens Axboe 1133a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1134a4514ebdSJens Axboe ret = -EFAULT; 1135a4514ebdSJens Axboe 1136a4514ebdSJens Axboe return ret; 1137529565dcSIngo Molnar } 11385274f052SJens Axboe 11390f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(out->f_path.dentry->d_inode); 1140529565dcSIngo Molnar if (pipe) { 1141529565dcSIngo Molnar if (off_out) 1142529565dcSIngo Molnar return -ESPIPE; 1143b92ce558SJens Axboe if (off_in) { 1144b92ce558SJens Axboe if (in->f_op->llseek == no_llseek) 1145b92ce558SJens Axboe return -EINVAL; 1146cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1147b92ce558SJens Axboe return -EFAULT; 1148cbb7e577SJens Axboe off = &offset; 1149cbb7e577SJens Axboe } else 1150cbb7e577SJens Axboe off = &in->f_pos; 1151529565dcSIngo Molnar 1152a4514ebdSJens Axboe ret = do_splice_to(in, off, pipe, len, flags); 1153a4514ebdSJens Axboe 1154a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1155a4514ebdSJens Axboe ret = -EFAULT; 1156a4514ebdSJens Axboe 1157a4514ebdSJens Axboe return ret; 1158529565dcSIngo Molnar } 11595274f052SJens Axboe 11605274f052SJens Axboe return -EINVAL; 11615274f052SJens Axboe } 11625274f052SJens Axboe 1163912d35f8SJens Axboe /* 116475723957SLinus Torvalds * Do a copy-from-user while holding the mmap_semaphore for reading, in a 116575723957SLinus Torvalds * manner safe from deadlocking with simultaneous mmap() (grabbing mmap_sem 116675723957SLinus Torvalds * for writing) and page faulting on the user memory pointed to by src. 116775723957SLinus Torvalds * This assumes that we will very rarely hit the partial != 0 path, or this 116875723957SLinus Torvalds * will not be a win. 116975723957SLinus Torvalds */ 117075723957SLinus Torvalds static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n) 117175723957SLinus Torvalds { 117275723957SLinus Torvalds int partial; 117375723957SLinus Torvalds 11748811930dSJens Axboe if (!access_ok(VERIFY_READ, src, n)) 11758811930dSJens Axboe return -EFAULT; 11768811930dSJens Axboe 117775723957SLinus Torvalds pagefault_disable(); 117875723957SLinus Torvalds partial = __copy_from_user_inatomic(dst, src, n); 117975723957SLinus Torvalds pagefault_enable(); 118075723957SLinus Torvalds 118175723957SLinus Torvalds /* 118275723957SLinus Torvalds * Didn't copy everything, drop the mmap_sem and do a faulting copy 118375723957SLinus Torvalds */ 118475723957SLinus Torvalds if (unlikely(partial)) { 118575723957SLinus Torvalds up_read(¤t->mm->mmap_sem); 118675723957SLinus Torvalds partial = copy_from_user(dst, src, n); 118775723957SLinus Torvalds down_read(¤t->mm->mmap_sem); 118875723957SLinus Torvalds } 118975723957SLinus Torvalds 119075723957SLinus Torvalds return partial; 119175723957SLinus Torvalds } 119275723957SLinus Torvalds 119375723957SLinus Torvalds /* 1194912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1195912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1196912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1197912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1198912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1199912d35f8SJens Axboe */ 1200912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1201912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 12027afa6fd0SJens Axboe struct partial_page *partial, int aligned) 1203912d35f8SJens Axboe { 1204912d35f8SJens Axboe int buffers = 0, error = 0; 1205912d35f8SJens Axboe 1206912d35f8SJens Axboe down_read(¤t->mm->mmap_sem); 1207912d35f8SJens Axboe 1208912d35f8SJens Axboe while (nr_vecs) { 1209912d35f8SJens Axboe unsigned long off, npages; 121075723957SLinus Torvalds struct iovec entry; 1211912d35f8SJens Axboe void __user *base; 1212912d35f8SJens Axboe size_t len; 1213912d35f8SJens Axboe int i; 1214912d35f8SJens Axboe 121575723957SLinus Torvalds error = -EFAULT; 121675723957SLinus Torvalds if (copy_from_user_mmap_sem(&entry, iov, sizeof(entry))) 1217912d35f8SJens Axboe break; 121875723957SLinus Torvalds 121975723957SLinus Torvalds base = entry.iov_base; 122075723957SLinus Torvalds len = entry.iov_len; 1221912d35f8SJens Axboe 1222912d35f8SJens Axboe /* 1223912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1224912d35f8SJens Axboe */ 122575723957SLinus Torvalds error = 0; 1226912d35f8SJens Axboe if (unlikely(!len)) 1227912d35f8SJens Axboe break; 1228912d35f8SJens Axboe error = -EFAULT; 1229712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1230912d35f8SJens Axboe break; 1231912d35f8SJens Axboe 1232912d35f8SJens Axboe /* 1233912d35f8SJens Axboe * Get this base offset and number of pages, then map 1234912d35f8SJens Axboe * in the user pages. 1235912d35f8SJens Axboe */ 1236912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 12377afa6fd0SJens Axboe 12387afa6fd0SJens Axboe /* 12397afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 12407afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 12417afa6fd0SJens Axboe */ 12427afa6fd0SJens Axboe error = -EINVAL; 12437afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 12447afa6fd0SJens Axboe break; 12457afa6fd0SJens Axboe 1246912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1247912d35f8SJens Axboe if (npages > PIPE_BUFFERS - buffers) 1248912d35f8SJens Axboe npages = PIPE_BUFFERS - buffers; 1249912d35f8SJens Axboe 1250912d35f8SJens Axboe error = get_user_pages(current, current->mm, 1251912d35f8SJens Axboe (unsigned long) base, npages, 0, 0, 1252912d35f8SJens Axboe &pages[buffers], NULL); 1253912d35f8SJens Axboe 1254912d35f8SJens Axboe if (unlikely(error <= 0)) 1255912d35f8SJens Axboe break; 1256912d35f8SJens Axboe 1257912d35f8SJens Axboe /* 1258912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1259912d35f8SJens Axboe */ 1260912d35f8SJens Axboe for (i = 0; i < error; i++) { 12617591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1262912d35f8SJens Axboe 1263912d35f8SJens Axboe partial[buffers].offset = off; 1264912d35f8SJens Axboe partial[buffers].len = plen; 1265912d35f8SJens Axboe 1266912d35f8SJens Axboe off = 0; 1267912d35f8SJens Axboe len -= plen; 1268912d35f8SJens Axboe buffers++; 1269912d35f8SJens Axboe } 1270912d35f8SJens Axboe 1271912d35f8SJens Axboe /* 1272912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1273912d35f8SJens Axboe * means we have to move some of this into a pipe to 1274912d35f8SJens Axboe * be able to continue. 1275912d35f8SJens Axboe */ 1276912d35f8SJens Axboe if (len) 1277912d35f8SJens Axboe break; 1278912d35f8SJens Axboe 1279912d35f8SJens Axboe /* 1280912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1281912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1282912d35f8SJens Axboe * room for. 1283912d35f8SJens Axboe */ 1284912d35f8SJens Axboe if (error < npages || buffers == PIPE_BUFFERS) 1285912d35f8SJens Axboe break; 1286912d35f8SJens Axboe 1287912d35f8SJens Axboe nr_vecs--; 1288912d35f8SJens Axboe iov++; 1289912d35f8SJens Axboe } 1290912d35f8SJens Axboe 1291912d35f8SJens Axboe up_read(¤t->mm->mmap_sem); 1292912d35f8SJens Axboe 1293912d35f8SJens Axboe if (buffers) 1294912d35f8SJens Axboe return buffers; 1295912d35f8SJens Axboe 1296912d35f8SJens Axboe return error; 1297912d35f8SJens Axboe } 1298912d35f8SJens Axboe 12996a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13006a14b90bSJens Axboe struct splice_desc *sd) 13016a14b90bSJens Axboe { 13026a14b90bSJens Axboe char *src; 13036a14b90bSJens Axboe int ret; 13046a14b90bSJens Axboe 1305cac36bb0SJens Axboe ret = buf->ops->confirm(pipe, buf); 13066a14b90bSJens Axboe if (unlikely(ret)) 13076a14b90bSJens Axboe return ret; 13086a14b90bSJens Axboe 13096a14b90bSJens Axboe /* 13106a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 13116a14b90bSJens Axboe * pages and doing an atomic copy 13126a14b90bSJens Axboe */ 13136a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 13146a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 13156a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 13166a14b90bSJens Axboe sd->len); 13176a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 13186a14b90bSJens Axboe if (!ret) { 13196a14b90bSJens Axboe ret = sd->len; 13206a14b90bSJens Axboe goto out; 13216a14b90bSJens Axboe } 13226a14b90bSJens Axboe } 13236a14b90bSJens Axboe 13246a14b90bSJens Axboe /* 13256a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 13266a14b90bSJens Axboe */ 13276a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 13286a14b90bSJens Axboe 13296a14b90bSJens Axboe ret = sd->len; 13306a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 13316a14b90bSJens Axboe ret = -EFAULT; 13326a14b90bSJens Axboe 13336866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 13346a14b90bSJens Axboe out: 13356a14b90bSJens Axboe if (ret > 0) 13366a14b90bSJens Axboe sd->u.userptr += ret; 13376a14b90bSJens Axboe return ret; 13386a14b90bSJens Axboe } 13396a14b90bSJens Axboe 13406a14b90bSJens Axboe /* 13416a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13426a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13436a14b90bSJens Axboe */ 13446a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 13456a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 13466a14b90bSJens Axboe { 13476a14b90bSJens Axboe struct pipe_inode_info *pipe; 13486a14b90bSJens Axboe struct splice_desc sd; 13496a14b90bSJens Axboe ssize_t size; 13506a14b90bSJens Axboe int error; 13516a14b90bSJens Axboe long ret; 13526a14b90bSJens Axboe 13536a14b90bSJens Axboe pipe = pipe_info(file->f_path.dentry->d_inode); 13546a14b90bSJens Axboe if (!pipe) 13556a14b90bSJens Axboe return -EBADF; 13566a14b90bSJens Axboe 13576a14b90bSJens Axboe if (pipe->inode) 13586a14b90bSJens Axboe mutex_lock(&pipe->inode->i_mutex); 13596a14b90bSJens Axboe 13606a14b90bSJens Axboe error = ret = 0; 13616a14b90bSJens Axboe while (nr_segs) { 13626a14b90bSJens Axboe void __user *base; 13636a14b90bSJens Axboe size_t len; 13646a14b90bSJens Axboe 13656a14b90bSJens Axboe /* 13666a14b90bSJens Axboe * Get user address base and length for this iovec. 13676a14b90bSJens Axboe */ 13686a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 13696a14b90bSJens Axboe if (unlikely(error)) 13706a14b90bSJens Axboe break; 13716a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 13726a14b90bSJens Axboe if (unlikely(error)) 13736a14b90bSJens Axboe break; 13746a14b90bSJens Axboe 13756a14b90bSJens Axboe /* 13766a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 13776a14b90bSJens Axboe */ 13786a14b90bSJens Axboe if (unlikely(!len)) 13796a14b90bSJens Axboe break; 13806a14b90bSJens Axboe if (unlikely(!base)) { 13816a14b90bSJens Axboe error = -EFAULT; 13826a14b90bSJens Axboe break; 13836a14b90bSJens Axboe } 13846a14b90bSJens Axboe 13858811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 13868811930dSJens Axboe error = -EFAULT; 13878811930dSJens Axboe break; 13888811930dSJens Axboe } 13898811930dSJens Axboe 13906a14b90bSJens Axboe sd.len = 0; 13916a14b90bSJens Axboe sd.total_len = len; 13926a14b90bSJens Axboe sd.flags = flags; 13936a14b90bSJens Axboe sd.u.userptr = base; 13946a14b90bSJens Axboe sd.pos = 0; 13956a14b90bSJens Axboe 13966a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 13976a14b90bSJens Axboe if (size < 0) { 13986a14b90bSJens Axboe if (!ret) 13996a14b90bSJens Axboe ret = size; 14006a14b90bSJens Axboe 14016a14b90bSJens Axboe break; 14026a14b90bSJens Axboe } 14036a14b90bSJens Axboe 14046a14b90bSJens Axboe ret += size; 14056a14b90bSJens Axboe 14066a14b90bSJens Axboe if (size < len) 14076a14b90bSJens Axboe break; 14086a14b90bSJens Axboe 14096a14b90bSJens Axboe nr_segs--; 14106a14b90bSJens Axboe iov++; 14116a14b90bSJens Axboe } 14126a14b90bSJens Axboe 14136a14b90bSJens Axboe if (pipe->inode) 14146a14b90bSJens Axboe mutex_unlock(&pipe->inode->i_mutex); 14156a14b90bSJens Axboe 14166a14b90bSJens Axboe if (!ret) 14176a14b90bSJens Axboe ret = error; 14186a14b90bSJens Axboe 14196a14b90bSJens Axboe return ret; 14206a14b90bSJens Axboe } 14216a14b90bSJens Axboe 1422912d35f8SJens Axboe /* 1423912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1424912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1425912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1426912d35f8SJens Axboe */ 14276a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1428912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1429912d35f8SJens Axboe { 1430ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1431912d35f8SJens Axboe struct page *pages[PIPE_BUFFERS]; 1432912d35f8SJens Axboe struct partial_page partial[PIPE_BUFFERS]; 1433912d35f8SJens Axboe struct splice_pipe_desc spd = { 1434912d35f8SJens Axboe .pages = pages, 1435912d35f8SJens Axboe .partial = partial, 1436912d35f8SJens Axboe .flags = flags, 1437912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1438bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1439912d35f8SJens Axboe }; 1440912d35f8SJens Axboe 14410f7fc9e4SJosef "Jeff" Sipek pipe = pipe_info(file->f_path.dentry->d_inode); 1442ddac0d39SJens Axboe if (!pipe) 1443912d35f8SJens Axboe return -EBADF; 1444912d35f8SJens Axboe 14457afa6fd0SJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, 14467afa6fd0SJens Axboe flags & SPLICE_F_GIFT); 1447912d35f8SJens Axboe if (spd.nr_pages <= 0) 1448912d35f8SJens Axboe return spd.nr_pages; 1449912d35f8SJens Axboe 145000522fb4SJens Axboe return splice_to_pipe(pipe, &spd); 1451912d35f8SJens Axboe } 1452912d35f8SJens Axboe 14536a14b90bSJens Axboe /* 14546a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14556a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14566a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14576a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14586a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14596a14b90bSJens Axboe * solutions for that: 14606a14b90bSJens Axboe * 14616a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14626a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14636a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14646a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14656a14b90bSJens Axboe * 14666a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14676a14b90bSJens Axboe * 14686a14b90bSJens Axboe */ 1469912d35f8SJens Axboe asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, 1470912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1471912d35f8SJens Axboe { 1472912d35f8SJens Axboe struct file *file; 1473912d35f8SJens Axboe long error; 1474912d35f8SJens Axboe int fput; 1475912d35f8SJens Axboe 14766a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 14776a14b90bSJens Axboe return -EINVAL; 14786a14b90bSJens Axboe else if (unlikely(!nr_segs)) 14796a14b90bSJens Axboe return 0; 14806a14b90bSJens Axboe 1481912d35f8SJens Axboe error = -EBADF; 1482912d35f8SJens Axboe file = fget_light(fd, &fput); 1483912d35f8SJens Axboe if (file) { 1484912d35f8SJens Axboe if (file->f_mode & FMODE_WRITE) 14856a14b90bSJens Axboe error = vmsplice_to_pipe(file, iov, nr_segs, flags); 14866a14b90bSJens Axboe else if (file->f_mode & FMODE_READ) 14876a14b90bSJens Axboe error = vmsplice_to_user(file, iov, nr_segs, flags); 1488912d35f8SJens Axboe 1489912d35f8SJens Axboe fput_light(file, fput); 1490912d35f8SJens Axboe } 1491912d35f8SJens Axboe 1492912d35f8SJens Axboe return error; 1493912d35f8SJens Axboe } 1494912d35f8SJens Axboe 1495529565dcSIngo Molnar asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, 1496529565dcSIngo Molnar int fd_out, loff_t __user *off_out, 1497529565dcSIngo Molnar size_t len, unsigned int flags) 14985274f052SJens Axboe { 14995274f052SJens Axboe long error; 15005274f052SJens Axboe struct file *in, *out; 15015274f052SJens Axboe int fput_in, fput_out; 15025274f052SJens Axboe 15035274f052SJens Axboe if (unlikely(!len)) 15045274f052SJens Axboe return 0; 15055274f052SJens Axboe 15065274f052SJens Axboe error = -EBADF; 1507529565dcSIngo Molnar in = fget_light(fd_in, &fput_in); 15085274f052SJens Axboe if (in) { 15095274f052SJens Axboe if (in->f_mode & FMODE_READ) { 1510529565dcSIngo Molnar out = fget_light(fd_out, &fput_out); 15115274f052SJens Axboe if (out) { 15125274f052SJens Axboe if (out->f_mode & FMODE_WRITE) 1513529565dcSIngo Molnar error = do_splice(in, off_in, 1514529565dcSIngo Molnar out, off_out, 1515529565dcSIngo Molnar len, flags); 15165274f052SJens Axboe fput_light(out, fput_out); 15175274f052SJens Axboe } 15185274f052SJens Axboe } 15195274f052SJens Axboe 15205274f052SJens Axboe fput_light(in, fput_in); 15215274f052SJens Axboe } 15225274f052SJens Axboe 15235274f052SJens Axboe return error; 15245274f052SJens Axboe } 152570524490SJens Axboe 152670524490SJens Axboe /* 1527aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1528aadd06e5SJens Axboe * return an appropriate error. 1529aadd06e5SJens Axboe */ 1530aadd06e5SJens Axboe static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1531aadd06e5SJens Axboe { 1532aadd06e5SJens Axboe int ret; 1533aadd06e5SJens Axboe 1534aadd06e5SJens Axboe /* 1535aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1536aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1537aadd06e5SJens Axboe */ 1538aadd06e5SJens Axboe if (pipe->nrbufs) 1539aadd06e5SJens Axboe return 0; 1540aadd06e5SJens Axboe 1541aadd06e5SJens Axboe ret = 0; 1542aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1543aadd06e5SJens Axboe 1544aadd06e5SJens Axboe while (!pipe->nrbufs) { 1545aadd06e5SJens Axboe if (signal_pending(current)) { 1546aadd06e5SJens Axboe ret = -ERESTARTSYS; 1547aadd06e5SJens Axboe break; 1548aadd06e5SJens Axboe } 1549aadd06e5SJens Axboe if (!pipe->writers) 1550aadd06e5SJens Axboe break; 1551aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1552aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1553aadd06e5SJens Axboe ret = -EAGAIN; 1554aadd06e5SJens Axboe break; 1555aadd06e5SJens Axboe } 1556aadd06e5SJens Axboe } 1557aadd06e5SJens Axboe pipe_wait(pipe); 1558aadd06e5SJens Axboe } 1559aadd06e5SJens Axboe 1560aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1561aadd06e5SJens Axboe return ret; 1562aadd06e5SJens Axboe } 1563aadd06e5SJens Axboe 1564aadd06e5SJens Axboe /* 1565aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1566aadd06e5SJens Axboe * return an appropriate error. 1567aadd06e5SJens Axboe */ 1568aadd06e5SJens Axboe static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1569aadd06e5SJens Axboe { 1570aadd06e5SJens Axboe int ret; 1571aadd06e5SJens Axboe 1572aadd06e5SJens Axboe /* 1573aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1574aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1575aadd06e5SJens Axboe */ 1576aadd06e5SJens Axboe if (pipe->nrbufs < PIPE_BUFFERS) 1577aadd06e5SJens Axboe return 0; 1578aadd06e5SJens Axboe 1579aadd06e5SJens Axboe ret = 0; 1580aadd06e5SJens Axboe mutex_lock(&pipe->inode->i_mutex); 1581aadd06e5SJens Axboe 1582aadd06e5SJens Axboe while (pipe->nrbufs >= PIPE_BUFFERS) { 1583aadd06e5SJens Axboe if (!pipe->readers) { 1584aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1585aadd06e5SJens Axboe ret = -EPIPE; 1586aadd06e5SJens Axboe break; 1587aadd06e5SJens Axboe } 1588aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1589aadd06e5SJens Axboe ret = -EAGAIN; 1590aadd06e5SJens Axboe break; 1591aadd06e5SJens Axboe } 1592aadd06e5SJens Axboe if (signal_pending(current)) { 1593aadd06e5SJens Axboe ret = -ERESTARTSYS; 1594aadd06e5SJens Axboe break; 1595aadd06e5SJens Axboe } 1596aadd06e5SJens Axboe pipe->waiting_writers++; 1597aadd06e5SJens Axboe pipe_wait(pipe); 1598aadd06e5SJens Axboe pipe->waiting_writers--; 1599aadd06e5SJens Axboe } 1600aadd06e5SJens Axboe 1601aadd06e5SJens Axboe mutex_unlock(&pipe->inode->i_mutex); 1602aadd06e5SJens Axboe return ret; 1603aadd06e5SJens Axboe } 1604aadd06e5SJens Axboe 1605aadd06e5SJens Axboe /* 160670524490SJens Axboe * Link contents of ipipe to opipe. 160770524490SJens Axboe */ 160870524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 160970524490SJens Axboe struct pipe_inode_info *opipe, 161070524490SJens Axboe size_t len, unsigned int flags) 161170524490SJens Axboe { 161270524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1613aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 161470524490SJens Axboe 161570524490SJens Axboe /* 161670524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 161770524490SJens Axboe * grabbing by inode address. Otherwise two different processes 161870524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 161970524490SJens Axboe */ 162062752ee1SMark Fasheh inode_double_lock(ipipe->inode, opipe->inode); 162170524490SJens Axboe 1622aadd06e5SJens Axboe do { 162370524490SJens Axboe if (!opipe->readers) { 162470524490SJens Axboe send_sig(SIGPIPE, current, 0); 162570524490SJens Axboe if (!ret) 162670524490SJens Axboe ret = -EPIPE; 162770524490SJens Axboe break; 162870524490SJens Axboe } 162970524490SJens Axboe 163070524490SJens Axboe /* 1631aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1632aadd06e5SJens Axboe * output room, break. 163370524490SJens Axboe */ 1634aadd06e5SJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) 1635aadd06e5SJens Axboe break; 1636aadd06e5SJens Axboe 1637aadd06e5SJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); 1638aadd06e5SJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); 163970524490SJens Axboe 164070524490SJens Axboe /* 164170524490SJens Axboe * Get a reference to this pipe buffer, 164270524490SJens Axboe * so we can copy the contents over. 164370524490SJens Axboe */ 164470524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 164570524490SJens Axboe 164670524490SJens Axboe obuf = opipe->bufs + nbuf; 164770524490SJens Axboe *obuf = *ibuf; 164870524490SJens Axboe 16497afa6fd0SJens Axboe /* 16507afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16517afa6fd0SJens Axboe * prevent multiple steals of this page. 16527afa6fd0SJens Axboe */ 16537afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16547afa6fd0SJens Axboe 165570524490SJens Axboe if (obuf->len > len) 165670524490SJens Axboe obuf->len = len; 165770524490SJens Axboe 165870524490SJens Axboe opipe->nrbufs++; 165970524490SJens Axboe ret += obuf->len; 166070524490SJens Axboe len -= obuf->len; 1661aadd06e5SJens Axboe i++; 1662aadd06e5SJens Axboe } while (len); 166370524490SJens Axboe 166402cf01aeSJens Axboe /* 166502cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 166602cf01aeSJens Axboe * future, otherwise just return 0 166702cf01aeSJens Axboe */ 166802cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 166902cf01aeSJens Axboe ret = -EAGAIN; 167002cf01aeSJens Axboe 167162752ee1SMark Fasheh inode_double_unlock(ipipe->inode, opipe->inode); 167270524490SJens Axboe 1673aadd06e5SJens Axboe /* 1674aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1675aadd06e5SJens Axboe */ 1676aadd06e5SJens Axboe if (ret > 0) { 167770524490SJens Axboe smp_mb(); 167870524490SJens Axboe if (waitqueue_active(&opipe->wait)) 167970524490SJens Axboe wake_up_interruptible(&opipe->wait); 168070524490SJens Axboe kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); 168170524490SJens Axboe } 168270524490SJens Axboe 168370524490SJens Axboe return ret; 168470524490SJens Axboe } 168570524490SJens Axboe 168670524490SJens Axboe /* 168770524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 168870524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 168970524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 169070524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 169170524490SJens Axboe */ 169270524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 169370524490SJens Axboe unsigned int flags) 169470524490SJens Axboe { 16950f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); 16960f7fc9e4SJosef "Jeff" Sipek struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); 1697aadd06e5SJens Axboe int ret = -EINVAL; 169870524490SJens Axboe 169970524490SJens Axboe /* 1700aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1701aadd06e5SJens Axboe * copying the data. 170270524490SJens Axboe */ 1703aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1704aadd06e5SJens Axboe /* 1705aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1706aadd06e5SJens Axboe * ordering doesn't really matter. 1707aadd06e5SJens Axboe */ 1708aadd06e5SJens Axboe ret = link_ipipe_prep(ipipe, flags); 1709aadd06e5SJens Axboe if (!ret) { 1710aadd06e5SJens Axboe ret = link_opipe_prep(opipe, flags); 171102cf01aeSJens Axboe if (!ret) 1712aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1713aadd06e5SJens Axboe } 1714aadd06e5SJens Axboe } 171570524490SJens Axboe 1716aadd06e5SJens Axboe return ret; 171770524490SJens Axboe } 171870524490SJens Axboe 171970524490SJens Axboe asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) 172070524490SJens Axboe { 172170524490SJens Axboe struct file *in; 172270524490SJens Axboe int error, fput_in; 172370524490SJens Axboe 172470524490SJens Axboe if (unlikely(!len)) 172570524490SJens Axboe return 0; 172670524490SJens Axboe 172770524490SJens Axboe error = -EBADF; 172870524490SJens Axboe in = fget_light(fdin, &fput_in); 172970524490SJens Axboe if (in) { 173070524490SJens Axboe if (in->f_mode & FMODE_READ) { 173170524490SJens Axboe int fput_out; 173270524490SJens Axboe struct file *out = fget_light(fdout, &fput_out); 173370524490SJens Axboe 173470524490SJens Axboe if (out) { 173570524490SJens Axboe if (out->f_mode & FMODE_WRITE) 173670524490SJens Axboe error = do_tee(in, out, len, flags); 173770524490SJens Axboe fput_light(out, fput_out); 173870524490SJens Axboe } 173970524490SJens Axboe } 174070524490SJens Axboe fput_light(in, fput_in); 174170524490SJens Axboe } 174270524490SJens Axboe 174370524490SJens Axboe return error; 174470524490SJens Axboe } 1745