1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 25274f052SJens Axboe /* 35274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 45274f052SJens Axboe * 55274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 65274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 75274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 85274f052SJens Axboe * 95274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 105274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 115274f052SJens Axboe * 125274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 13c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 14c2058e06SJens Axboe * fixing lots of bugs. 155274f052SJens Axboe * 160fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 17c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 18c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 195274f052SJens Axboe * 205274f052SJens Axboe */ 21be297968SChristoph Hellwig #include <linux/bvec.h> 225274f052SJens Axboe #include <linux/fs.h> 235274f052SJens Axboe #include <linux/file.h> 245274f052SJens Axboe #include <linux/pagemap.h> 25d6b29d7cSJens Axboe #include <linux/splice.h> 2608e552c6SKAMEZAWA Hiroyuki #include <linux/memcontrol.h> 275274f052SJens Axboe #include <linux/mm_inline.h> 285abc97aaSJens Axboe #include <linux/swap.h> 294f6f0bd2SJens Axboe #include <linux/writeback.h> 30630d9c47SPaul Gortmaker #include <linux/export.h> 314f6f0bd2SJens Axboe #include <linux/syscalls.h> 32912d35f8SJens Axboe #include <linux/uio.h> 33*983652c6SChung-Chiang Cheng #include <linux/fsnotify.h> 3429ce2058SJames Morris #include <linux/security.h> 355a0e3ad6STejun Heo #include <linux/gfp.h> 3635f9c09fSEric Dumazet #include <linux/socket.h> 37174cd4b1SIngo Molnar #include <linux/sched/signal.h> 38174cd4b1SIngo Molnar 3906ae43f3SAl Viro #include "internal.h" 405274f052SJens Axboe 4183f9135bSJens Axboe /* 4283f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 4383f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 4483f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 4583f9135bSJens Axboe * attempt to reuse this page for another destination. 4683f9135bSJens Axboe */ 47c928f642SChristoph Hellwig static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, 485abc97aaSJens Axboe struct pipe_buffer *buf) 495abc97aaSJens Axboe { 505100da38SMatthew Wilcox (Oracle) struct folio *folio = page_folio(buf->page); 519e94cd4fSJens Axboe struct address_space *mapping; 525abc97aaSJens Axboe 53b9ccad2eSMatthew Wilcox (Oracle) folio_lock(folio); 549e0267c2SJens Axboe 55b9ccad2eSMatthew Wilcox (Oracle) mapping = folio_mapping(folio); 569e94cd4fSJens Axboe if (mapping) { 57b9ccad2eSMatthew Wilcox (Oracle) WARN_ON(!folio_test_uptodate(folio)); 585abc97aaSJens Axboe 59ad8d6f0aSJens Axboe /* 609e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 61b9ccad2eSMatthew Wilcox (Oracle) * writeback completing on this folio, since we'll remove it 629e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 63b9ccad2eSMatthew Wilcox (Oracle) * folio, allowing the disk blocks to be reused by someone else 649e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 659e94cd4fSJens Axboe * ensues. 66ad8d6f0aSJens Axboe */ 67b9ccad2eSMatthew Wilcox (Oracle) folio_wait_writeback(folio); 68ad8d6f0aSJens Axboe 69b9ccad2eSMatthew Wilcox (Oracle) if (folio_has_private(folio) && 70b9ccad2eSMatthew Wilcox (Oracle) !filemap_release_folio(folio, GFP_KERNEL)) 71ca39d651SJens Axboe goto out_unlock; 724f6f0bd2SJens Axboe 739e94cd4fSJens Axboe /* 749e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 759e94cd4fSJens Axboe * and return good. 769e94cd4fSJens Axboe */ 775100da38SMatthew Wilcox (Oracle) if (remove_mapping(mapping, folio)) { 781432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 79c928f642SChristoph Hellwig return true; 805abc97aaSJens Axboe } 819e94cd4fSJens Axboe } 829e94cd4fSJens Axboe 839e94cd4fSJens Axboe /* 84b9ccad2eSMatthew Wilcox (Oracle) * Raced with truncate or failed to remove folio from current 859e94cd4fSJens Axboe * address space, unlock and return failure. 869e94cd4fSJens Axboe */ 87ca39d651SJens Axboe out_unlock: 88b9ccad2eSMatthew Wilcox (Oracle) folio_unlock(folio); 89c928f642SChristoph Hellwig return false; 909e94cd4fSJens Axboe } 915abc97aaSJens Axboe 9276ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 935274f052SJens Axboe struct pipe_buffer *buf) 945274f052SJens Axboe { 9509cbfeafSKirill A. Shutemov put_page(buf->page); 961432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 975274f052SJens Axboe } 985274f052SJens Axboe 990845718dSJens Axboe /* 1000845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 1010845718dSJens Axboe * is a page cache page, IO may be in flight. 1020845718dSJens Axboe */ 103cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 1045274f052SJens Axboe struct pipe_buffer *buf) 1055274f052SJens Axboe { 1065274f052SJens Axboe struct page *page = buf->page; 10749d0b21bSJens Axboe int err; 1085274f052SJens Axboe 1095274f052SJens Axboe if (!PageUptodate(page)) { 11049d0b21bSJens Axboe lock_page(page); 1115274f052SJens Axboe 11249d0b21bSJens Axboe /* 11349d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 11473d62d83SIngo Molnar * splice, if this is the first page. 11549d0b21bSJens Axboe */ 1165274f052SJens Axboe if (!page->mapping) { 11749d0b21bSJens Axboe err = -ENODATA; 11849d0b21bSJens Axboe goto error; 1195274f052SJens Axboe } 1205274f052SJens Axboe 12149d0b21bSJens Axboe /* 12273d62d83SIngo Molnar * Uh oh, read-error from disk. 12349d0b21bSJens Axboe */ 12449d0b21bSJens Axboe if (!PageUptodate(page)) { 12549d0b21bSJens Axboe err = -EIO; 12649d0b21bSJens Axboe goto error; 12749d0b21bSJens Axboe } 12849d0b21bSJens Axboe 12949d0b21bSJens Axboe /* 130f84d7519SJens Axboe * Page is ok afterall, we are done. 13149d0b21bSJens Axboe */ 13249d0b21bSJens Axboe unlock_page(page); 13349d0b21bSJens Axboe } 13449d0b21bSJens Axboe 135f84d7519SJens Axboe return 0; 13649d0b21bSJens Axboe error: 13749d0b21bSJens Axboe unlock_page(page); 138f84d7519SJens Axboe return err; 13970524490SJens Axboe } 14070524490SJens Axboe 141708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 142cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1435274f052SJens Axboe .release = page_cache_pipe_buf_release, 144c928f642SChristoph Hellwig .try_steal = page_cache_pipe_buf_try_steal, 145f84d7519SJens Axboe .get = generic_pipe_buf_get, 1465274f052SJens Axboe }; 1475274f052SJens Axboe 148c928f642SChristoph Hellwig static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, 149912d35f8SJens Axboe struct pipe_buffer *buf) 150912d35f8SJens Axboe { 1517afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 152c928f642SChristoph Hellwig return false; 1537afa6fd0SJens Axboe 1541432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 155c928f642SChristoph Hellwig return generic_pipe_buf_try_steal(pipe, buf); 156912d35f8SJens Axboe } 157912d35f8SJens Axboe 158d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 159912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 160c928f642SChristoph Hellwig .try_steal = user_page_pipe_buf_try_steal, 161f84d7519SJens Axboe .get = generic_pipe_buf_get, 162912d35f8SJens Axboe }; 163912d35f8SJens Axboe 164825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 165825cdcb1SNamhyung Kim { 166825cdcb1SNamhyung Kim smp_mb(); 1670ddad21dSLinus Torvalds if (waitqueue_active(&pipe->rd_wait)) 1680ddad21dSLinus Torvalds wake_up_interruptible(&pipe->rd_wait); 169825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 170825cdcb1SNamhyung Kim } 171825cdcb1SNamhyung Kim 172932cc6d4SJens Axboe /** 173932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 174932cc6d4SJens Axboe * @pipe: pipe to fill 175932cc6d4SJens Axboe * @spd: data to fill 176932cc6d4SJens Axboe * 177932cc6d4SJens Axboe * Description: 17879685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 179932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 180932cc6d4SJens Axboe * function will link that data to the pipe. 181932cc6d4SJens Axboe * 18283f9135bSJens Axboe */ 183d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 184912d35f8SJens Axboe struct splice_pipe_desc *spd) 1855274f052SJens Axboe { 18600de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 1878cefc107SDavid Howells unsigned int tail = pipe->tail; 1888cefc107SDavid Howells unsigned int head = pipe->head; 1898cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 1908924feffSAl Viro int ret = 0, page_nr = 0; 1915274f052SJens Axboe 192d6785d91SRabin Vincent if (!spd_pages) 193d6785d91SRabin Vincent return 0; 194d6785d91SRabin Vincent 1958924feffSAl Viro if (unlikely(!pipe->readers)) { 1965274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1975274f052SJens Axboe ret = -EPIPE; 1988924feffSAl Viro goto out; 1995274f052SJens Axboe } 2005274f052SJens Axboe 2016718b6f8SDavid Howells while (!pipe_full(head, tail, pipe->max_usage)) { 2028cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[head & mask]; 2035274f052SJens Axboe 204912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 205912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 206912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 207497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 208912d35f8SJens Axboe buf->ops = spd->ops; 2095a81e6a1SMiklos Szeredi buf->flags = 0; 2107afa6fd0SJens Axboe 2118cefc107SDavid Howells head++; 2128cefc107SDavid Howells pipe->head = head; 213912d35f8SJens Axboe page_nr++; 214912d35f8SJens Axboe ret += buf->len; 215912d35f8SJens Axboe 216912d35f8SJens Axboe if (!--spd->nr_pages) 2175274f052SJens Axboe break; 2185274f052SJens Axboe } 2195274f052SJens Axboe 22029e35094SLinus Torvalds if (!ret) 22129e35094SLinus Torvalds ret = -EAGAIN; 22229e35094SLinus Torvalds 2238924feffSAl Viro out: 22400de00bdSJens Axboe while (page_nr < spd_pages) 225bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2265274f052SJens Axboe 2275274f052SJens Axboe return ret; 2285274f052SJens Axboe } 2292b514574SHannes Frederic Sowa EXPORT_SYMBOL_GPL(splice_to_pipe); 2305274f052SJens Axboe 23179fddc4eSAl Viro ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 23279fddc4eSAl Viro { 2338cefc107SDavid Howells unsigned int head = pipe->head; 2348cefc107SDavid Howells unsigned int tail = pipe->tail; 2358cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 23679fddc4eSAl Viro int ret; 23779fddc4eSAl Viro 23879fddc4eSAl Viro if (unlikely(!pipe->readers)) { 23979fddc4eSAl Viro send_sig(SIGPIPE, current, 0); 24079fddc4eSAl Viro ret = -EPIPE; 2416718b6f8SDavid Howells } else if (pipe_full(head, tail, pipe->max_usage)) { 24279fddc4eSAl Viro ret = -EAGAIN; 24379fddc4eSAl Viro } else { 2448cefc107SDavid Howells pipe->bufs[head & mask] = *buf; 2458cefc107SDavid Howells pipe->head = head + 1; 24679fddc4eSAl Viro return buf->len; 24779fddc4eSAl Viro } 248a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 24979fddc4eSAl Viro return ret; 25079fddc4eSAl Viro } 25179fddc4eSAl Viro EXPORT_SYMBOL(add_to_pipe); 25279fddc4eSAl Viro 25335f3d14dSJens Axboe /* 25435f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 25535f3d14dSJens Axboe * descriptions. 25635f3d14dSJens Axboe */ 257047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 25835f3d14dSJens Axboe { 2596718b6f8SDavid Howells unsigned int max_usage = READ_ONCE(pipe->max_usage); 260047fe360SEric Dumazet 2618cefc107SDavid Howells spd->nr_pages_max = max_usage; 2628cefc107SDavid Howells if (max_usage <= PIPE_DEF_BUFFERS) 26335f3d14dSJens Axboe return 0; 26435f3d14dSJens Axboe 2658cefc107SDavid Howells spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); 2668cefc107SDavid Howells spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), 2676da2ec56SKees Cook GFP_KERNEL); 26835f3d14dSJens Axboe 26935f3d14dSJens Axboe if (spd->pages && spd->partial) 27035f3d14dSJens Axboe return 0; 27135f3d14dSJens Axboe 27235f3d14dSJens Axboe kfree(spd->pages); 27335f3d14dSJens Axboe kfree(spd->partial); 27435f3d14dSJens Axboe return -ENOMEM; 27535f3d14dSJens Axboe } 27635f3d14dSJens Axboe 277047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 27835f3d14dSJens Axboe { 279047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 28035f3d14dSJens Axboe return; 28135f3d14dSJens Axboe 28235f3d14dSJens Axboe kfree(spd->pages); 28335f3d14dSJens Axboe kfree(spd->partial); 28435f3d14dSJens Axboe } 28535f3d14dSJens Axboe 28633b3b041SDavid Howells /* 28733b3b041SDavid Howells * Splice data from an O_DIRECT file into pages and then add them to the output 28833b3b041SDavid Howells * pipe. 28933b3b041SDavid Howells */ 29033b3b041SDavid Howells ssize_t direct_splice_read(struct file *in, loff_t *ppos, 29133b3b041SDavid Howells struct pipe_inode_info *pipe, 29233b3b041SDavid Howells size_t len, unsigned int flags) 29333b3b041SDavid Howells { 29433b3b041SDavid Howells struct iov_iter to; 29533b3b041SDavid Howells struct bio_vec *bv; 29633b3b041SDavid Howells struct kiocb kiocb; 29733b3b041SDavid Howells struct page **pages; 29833b3b041SDavid Howells ssize_t ret; 29933b3b041SDavid Howells size_t used, npages, chunk, remain, reclaim; 30033b3b041SDavid Howells int i; 30133b3b041SDavid Howells 30233b3b041SDavid Howells /* Work out how much data we can actually add into the pipe */ 30333b3b041SDavid Howells used = pipe_occupancy(pipe->head, pipe->tail); 30433b3b041SDavid Howells npages = max_t(ssize_t, pipe->max_usage - used, 0); 30533b3b041SDavid Howells len = min_t(size_t, len, npages * PAGE_SIZE); 30633b3b041SDavid Howells npages = DIV_ROUND_UP(len, PAGE_SIZE); 30733b3b041SDavid Howells 30833b3b041SDavid Howells bv = kzalloc(array_size(npages, sizeof(bv[0])) + 30933b3b041SDavid Howells array_size(npages, sizeof(struct page *)), GFP_KERNEL); 31033b3b041SDavid Howells if (!bv) 31133b3b041SDavid Howells return -ENOMEM; 31233b3b041SDavid Howells 31333b3b041SDavid Howells pages = (void *)(bv + npages); 31433b3b041SDavid Howells npages = alloc_pages_bulk_array(GFP_USER, npages, pages); 31533b3b041SDavid Howells if (!npages) { 31633b3b041SDavid Howells kfree(bv); 31733b3b041SDavid Howells return -ENOMEM; 31833b3b041SDavid Howells } 31933b3b041SDavid Howells 32033b3b041SDavid Howells remain = len = min_t(size_t, len, npages * PAGE_SIZE); 32133b3b041SDavid Howells 32233b3b041SDavid Howells for (i = 0; i < npages; i++) { 32333b3b041SDavid Howells chunk = min_t(size_t, PAGE_SIZE, remain); 32433b3b041SDavid Howells bv[i].bv_page = pages[i]; 32533b3b041SDavid Howells bv[i].bv_offset = 0; 32633b3b041SDavid Howells bv[i].bv_len = chunk; 32733b3b041SDavid Howells remain -= chunk; 32833b3b041SDavid Howells } 32933b3b041SDavid Howells 33033b3b041SDavid Howells /* Do the I/O */ 33133b3b041SDavid Howells iov_iter_bvec(&to, ITER_DEST, bv, npages, len); 33233b3b041SDavid Howells init_sync_kiocb(&kiocb, in); 33333b3b041SDavid Howells kiocb.ki_pos = *ppos; 33433b3b041SDavid Howells ret = call_read_iter(in, &kiocb, &to); 33533b3b041SDavid Howells 33633b3b041SDavid Howells reclaim = npages * PAGE_SIZE; 33733b3b041SDavid Howells remain = 0; 33833b3b041SDavid Howells if (ret > 0) { 33933b3b041SDavid Howells reclaim -= ret; 34033b3b041SDavid Howells remain = ret; 34133b3b041SDavid Howells *ppos = kiocb.ki_pos; 34233b3b041SDavid Howells file_accessed(in); 34333b3b041SDavid Howells } else if (ret < 0) { 34433b3b041SDavid Howells /* 34533b3b041SDavid Howells * callers of ->splice_read() expect -EAGAIN on 34633b3b041SDavid Howells * "can't put anything in there", rather than -EFAULT. 34733b3b041SDavid Howells */ 34833b3b041SDavid Howells if (ret == -EFAULT) 34933b3b041SDavid Howells ret = -EAGAIN; 35033b3b041SDavid Howells } 35133b3b041SDavid Howells 35233b3b041SDavid Howells /* Free any pages that didn't get touched at all. */ 35333b3b041SDavid Howells reclaim /= PAGE_SIZE; 35433b3b041SDavid Howells if (reclaim) { 35533b3b041SDavid Howells npages -= reclaim; 35633b3b041SDavid Howells release_pages(pages + npages, reclaim); 35733b3b041SDavid Howells } 35833b3b041SDavid Howells 35933b3b041SDavid Howells /* Push the remaining pages into the pipe. */ 36033b3b041SDavid Howells for (i = 0; i < npages; i++) { 36133b3b041SDavid Howells struct pipe_buffer *buf = pipe_head_buf(pipe); 36233b3b041SDavid Howells 36333b3b041SDavid Howells chunk = min_t(size_t, remain, PAGE_SIZE); 36433b3b041SDavid Howells *buf = (struct pipe_buffer) { 36533b3b041SDavid Howells .ops = &default_pipe_buf_ops, 36633b3b041SDavid Howells .page = bv[i].bv_page, 36733b3b041SDavid Howells .offset = 0, 36833b3b041SDavid Howells .len = chunk, 36933b3b041SDavid Howells }; 37033b3b041SDavid Howells pipe->head++; 37133b3b041SDavid Howells remain -= chunk; 37233b3b041SDavid Howells } 37333b3b041SDavid Howells 37433b3b041SDavid Howells kfree(bv); 37533b3b041SDavid Howells return ret; 37633b3b041SDavid Howells } 3777c8e01ebSDavid Howells EXPORT_SYMBOL(direct_splice_read); 37833b3b041SDavid Howells 37983f9135bSJens Axboe /** 38083f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 38183f9135bSJens Axboe * @in: file to splice from 382932cc6d4SJens Axboe * @ppos: position in @in 38383f9135bSJens Axboe * @pipe: pipe to splice to 38483f9135bSJens Axboe * @len: number of bytes to splice 38583f9135bSJens Axboe * @flags: splice modifier flags 38683f9135bSJens Axboe * 387932cc6d4SJens Axboe * Description: 388932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 38982c156f8SAl Viro * used as long as it has more or less sane ->read_iter(). 390932cc6d4SJens Axboe * 39183f9135bSJens Axboe */ 392cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 393cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 394cbb7e577SJens Axboe unsigned int flags) 3955274f052SJens Axboe { 39682c156f8SAl Viro struct iov_iter to; 39782c156f8SAl Viro struct kiocb kiocb; 3988cefc107SDavid Howells int ret; 399be64f884SBoaz Harrosh 400de4eda9dSAl Viro iov_iter_pipe(&to, ITER_DEST, pipe, len); 40182c156f8SAl Viro init_sync_kiocb(&kiocb, in); 40282c156f8SAl Viro kiocb.ki_pos = *ppos; 403bb7462b6SMiklos Szeredi ret = call_read_iter(in, &kiocb, &to); 404723590edSMiklos Szeredi if (ret > 0) { 40582c156f8SAl Viro *ppos = kiocb.ki_pos; 406723590edSMiklos Szeredi file_accessed(in); 40782c156f8SAl Viro } else if (ret < 0) { 4080d964934SAl Viro /* free what was emitted */ 4090d964934SAl Viro pipe_discard_from(pipe, to.start_head); 41082c156f8SAl Viro /* 41182c156f8SAl Viro * callers of ->splice_read() expect -EAGAIN on 41282c156f8SAl Viro * "can't put anything in there", rather than -EFAULT. 41382c156f8SAl Viro */ 41482c156f8SAl Viro if (ret == -EFAULT) 41582c156f8SAl Viro ret = -EAGAIN; 416723590edSMiklos Szeredi } 4175274f052SJens Axboe 4185274f052SJens Axboe return ret; 4195274f052SJens Axboe } 420059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 421059a8f37SJens Axboe 422241699cdSAl Viro const struct pipe_buf_operations default_pipe_buf_ops = { 4236818173bSMiklos Szeredi .release = generic_pipe_buf_release, 424c928f642SChristoph Hellwig .try_steal = generic_pipe_buf_try_steal, 4256818173bSMiklos Szeredi .get = generic_pipe_buf_get, 4266818173bSMiklos Szeredi }; 4276818173bSMiklos Szeredi 42828a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 42928a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 43028a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 43128a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 43228a625cbSMiklos Szeredi }; 43328a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 43428a625cbSMiklos Szeredi 4355274f052SJens Axboe /* 4364f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 437016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4385274f052SJens Axboe */ 43976ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 4405274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4415274f052SJens Axboe { 4426a14b90bSJens Axboe struct file *file = sd->u.file; 4435274f052SJens Axboe loff_t pos = sd->pos; 444a8adbe37SMichał Mirosław int more; 4455274f052SJens Axboe 44672c2d531SAl Viro if (!likely(file->f_op->sendpage)) 447a8adbe37SMichał Mirosław return -EINVAL; 448a8adbe37SMichał Mirosław 44935f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 450ae62ca7bSEric Dumazet 4518cefc107SDavid Howells if (sd->len < sd->total_len && 4528cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail) > 1) 45335f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 454ae62ca7bSEric Dumazet 455a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 456f84d7519SJens Axboe sd->len, &pos, more); 4575274f052SJens Axboe } 4585274f052SJens Axboe 459b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 460b3c2d2ddSMiklos Szeredi { 461b3c2d2ddSMiklos Szeredi smp_mb(); 4620ddad21dSLinus Torvalds if (waitqueue_active(&pipe->wr_wait)) 4630ddad21dSLinus Torvalds wake_up_interruptible(&pipe->wr_wait); 464b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 465b3c2d2ddSMiklos Szeredi } 466b3c2d2ddSMiklos Szeredi 467b3c2d2ddSMiklos Szeredi /** 468b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 469b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 470b3c2d2ddSMiklos Szeredi * @sd: information to @actor 471b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 472b3c2d2ddSMiklos Szeredi * 473b3c2d2ddSMiklos Szeredi * Description: 474b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 475b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 476b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 477b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 478b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 479b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 480b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 481b3c2d2ddSMiklos Szeredi * 482b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 483b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 484b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 485b3c2d2ddSMiklos Szeredi * destination. 486b3c2d2ddSMiklos Szeredi */ 48796f9bc8fSAl Viro static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 488b3c2d2ddSMiklos Szeredi splice_actor *actor) 489b3c2d2ddSMiklos Szeredi { 4908cefc107SDavid Howells unsigned int head = pipe->head; 4918cefc107SDavid Howells unsigned int tail = pipe->tail; 4928cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 493b3c2d2ddSMiklos Szeredi int ret; 494b3c2d2ddSMiklos Szeredi 495ec057595SLinus Torvalds while (!pipe_empty(head, tail)) { 4968cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 497b3c2d2ddSMiklos Szeredi 498b3c2d2ddSMiklos Szeredi sd->len = buf->len; 499b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 500b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 501b3c2d2ddSMiklos Szeredi 502fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 503a8adbe37SMichał Mirosław if (unlikely(ret)) { 504b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 505b3c2d2ddSMiklos Szeredi ret = 0; 506b3c2d2ddSMiklos Szeredi return ret; 507b3c2d2ddSMiklos Szeredi } 508a8adbe37SMichał Mirosław 509a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 510a8adbe37SMichał Mirosław if (ret <= 0) 511a8adbe37SMichał Mirosław return ret; 512a8adbe37SMichał Mirosław 513b3c2d2ddSMiklos Szeredi buf->offset += ret; 514b3c2d2ddSMiklos Szeredi buf->len -= ret; 515b3c2d2ddSMiklos Szeredi 516b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 517b3c2d2ddSMiklos Szeredi sd->len -= ret; 518b3c2d2ddSMiklos Szeredi sd->pos += ret; 519b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 520b3c2d2ddSMiklos Szeredi 521b3c2d2ddSMiklos Szeredi if (!buf->len) { 522a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 5238cefc107SDavid Howells tail++; 5248cefc107SDavid Howells pipe->tail = tail; 5256447a3cfSAl Viro if (pipe->files) 526b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 527b3c2d2ddSMiklos Szeredi } 528b3c2d2ddSMiklos Szeredi 529b3c2d2ddSMiklos Szeredi if (!sd->total_len) 530b3c2d2ddSMiklos Szeredi return 0; 531b3c2d2ddSMiklos Szeredi } 532b3c2d2ddSMiklos Szeredi 533b3c2d2ddSMiklos Szeredi return 1; 534b3c2d2ddSMiklos Szeredi } 535b3c2d2ddSMiklos Szeredi 536d1a819a2SLinus Torvalds /* We know we have a pipe buffer, but maybe it's empty? */ 537d1a819a2SLinus Torvalds static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) 538d1a819a2SLinus Torvalds { 539d1a819a2SLinus Torvalds unsigned int tail = pipe->tail; 540d1a819a2SLinus Torvalds unsigned int mask = pipe->ring_size - 1; 541d1a819a2SLinus Torvalds struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 542d1a819a2SLinus Torvalds 543d1a819a2SLinus Torvalds if (unlikely(!buf->len)) { 544d1a819a2SLinus Torvalds pipe_buf_release(pipe, buf); 545d1a819a2SLinus Torvalds pipe->tail = tail+1; 546d1a819a2SLinus Torvalds return true; 547d1a819a2SLinus Torvalds } 548d1a819a2SLinus Torvalds 549d1a819a2SLinus Torvalds return false; 550d1a819a2SLinus Torvalds } 551d1a819a2SLinus Torvalds 552b3c2d2ddSMiklos Szeredi /** 553b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 554b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 555b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 556b3c2d2ddSMiklos Szeredi * 557b3c2d2ddSMiklos Szeredi * Description: 558b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 559b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 560b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 561b3c2d2ddSMiklos Szeredi */ 56296f9bc8fSAl Viro static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 563b3c2d2ddSMiklos Szeredi { 564c725bfceSJan Kara /* 565c725bfceSJan Kara * Check for signal early to make process killable when there are 566c725bfceSJan Kara * always buffers available 567c725bfceSJan Kara */ 568c725bfceSJan Kara if (signal_pending(current)) 569c725bfceSJan Kara return -ERESTARTSYS; 570c725bfceSJan Kara 571d1a819a2SLinus Torvalds repeat: 5728cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 573b3c2d2ddSMiklos Szeredi if (!pipe->writers) 574b3c2d2ddSMiklos Szeredi return 0; 575b3c2d2ddSMiklos Szeredi 576a28c8b9dSLinus Torvalds if (sd->num_spliced) 577b3c2d2ddSMiklos Szeredi return 0; 578b3c2d2ddSMiklos Szeredi 579b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 580b3c2d2ddSMiklos Szeredi return -EAGAIN; 581b3c2d2ddSMiklos Szeredi 582b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 583b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 584b3c2d2ddSMiklos Szeredi 585b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 586b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 587b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 588b3c2d2ddSMiklos Szeredi } 589b3c2d2ddSMiklos Szeredi 590472e5b05SLinus Torvalds pipe_wait_readable(pipe); 591b3c2d2ddSMiklos Szeredi } 592b3c2d2ddSMiklos Szeredi 593d1a819a2SLinus Torvalds if (eat_empty_buffer(pipe)) 594d1a819a2SLinus Torvalds goto repeat; 595d1a819a2SLinus Torvalds 596b3c2d2ddSMiklos Szeredi return 1; 597b3c2d2ddSMiklos Szeredi } 598b3c2d2ddSMiklos Szeredi 599b3c2d2ddSMiklos Szeredi /** 600b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 601b80901bbSRandy Dunlap * @sd: information about the splice operation 602b3c2d2ddSMiklos Szeredi * 603b3c2d2ddSMiklos Szeredi * Description: 604b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 605b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 606b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 607b3c2d2ddSMiklos Szeredi */ 60896f9bc8fSAl Viro static void splice_from_pipe_begin(struct splice_desc *sd) 609b3c2d2ddSMiklos Szeredi { 610b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 611b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 612b3c2d2ddSMiklos Szeredi } 613b3c2d2ddSMiklos Szeredi 614b3c2d2ddSMiklos Szeredi /** 615b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 616b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 617b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 618b3c2d2ddSMiklos Szeredi * 619b3c2d2ddSMiklos Szeredi * Description: 620b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 621b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 622b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 623b3c2d2ddSMiklos Szeredi */ 62496f9bc8fSAl Viro static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 625b3c2d2ddSMiklos Szeredi { 626b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 627b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 628b3c2d2ddSMiklos Szeredi } 629b3c2d2ddSMiklos Szeredi 630932cc6d4SJens Axboe /** 631932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 632932cc6d4SJens Axboe * @pipe: pipe to splice from 633932cc6d4SJens Axboe * @sd: information to @actor 634932cc6d4SJens Axboe * @actor: handler that splices the data 635932cc6d4SJens Axboe * 636932cc6d4SJens Axboe * Description: 637932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 638932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 639932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 640932cc6d4SJens Axboe * pipe_to_user. 641932cc6d4SJens Axboe * 64283f9135bSJens Axboe */ 643c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 644c66ab6faSJens Axboe splice_actor *actor) 6455274f052SJens Axboe { 646b3c2d2ddSMiklos Szeredi int ret; 6475274f052SJens Axboe 648b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 649b3c2d2ddSMiklos Szeredi do { 650c2489e07SJan Kara cond_resched(); 651b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 652b3c2d2ddSMiklos Szeredi if (ret > 0) 653b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 654b3c2d2ddSMiklos Szeredi } while (ret > 0); 655b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 6565274f052SJens Axboe 657b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 6585274f052SJens Axboe } 65940bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6605274f052SJens Axboe 661932cc6d4SJens Axboe /** 662932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 663932cc6d4SJens Axboe * @pipe: pipe to splice from 664932cc6d4SJens Axboe * @out: file to splice to 665932cc6d4SJens Axboe * @ppos: position in @out 666932cc6d4SJens Axboe * @len: how many bytes to splice 667932cc6d4SJens Axboe * @flags: splice modifier flags 668932cc6d4SJens Axboe * @actor: handler that splices the data 669932cc6d4SJens Axboe * 670932cc6d4SJens Axboe * Description: 6712933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 672932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 673932cc6d4SJens Axboe * 674932cc6d4SJens Axboe */ 6756da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 6766da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 6776da61809SMark Fasheh splice_actor *actor) 6786da61809SMark Fasheh { 6796da61809SMark Fasheh ssize_t ret; 680c66ab6faSJens Axboe struct splice_desc sd = { 681c66ab6faSJens Axboe .total_len = len, 682c66ab6faSJens Axboe .flags = flags, 683c66ab6faSJens Axboe .pos = *ppos, 6846a14b90bSJens Axboe .u.file = out, 685c66ab6faSJens Axboe }; 6866da61809SMark Fasheh 68761e0d47cSMiklos Szeredi pipe_lock(pipe); 688c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 68961e0d47cSMiklos Szeredi pipe_unlock(pipe); 6906da61809SMark Fasheh 6916da61809SMark Fasheh return ret; 6926da61809SMark Fasheh } 6936da61809SMark Fasheh 6946da61809SMark Fasheh /** 6958d020765SAl Viro * iter_file_splice_write - splice data from a pipe to a file 6968d020765SAl Viro * @pipe: pipe info 6978d020765SAl Viro * @out: file to write to 6988d020765SAl Viro * @ppos: position in @out 6998d020765SAl Viro * @len: number of bytes to splice 7008d020765SAl Viro * @flags: splice modifier flags 7018d020765SAl Viro * 7028d020765SAl Viro * Description: 7038d020765SAl Viro * Will either move or copy pages (determined by @flags options) from 7048d020765SAl Viro * the given pipe inode to the given file. 7058d020765SAl Viro * This one is ->write_iter-based. 7068d020765SAl Viro * 7078d020765SAl Viro */ 7088d020765SAl Viro ssize_t 7098d020765SAl Viro iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 7108d020765SAl Viro loff_t *ppos, size_t len, unsigned int flags) 7118d020765SAl Viro { 7128d020765SAl Viro struct splice_desc sd = { 7138d020765SAl Viro .total_len = len, 7148d020765SAl Viro .flags = flags, 7158d020765SAl Viro .pos = *ppos, 7168d020765SAl Viro .u.file = out, 7178d020765SAl Viro }; 7186718b6f8SDavid Howells int nbufs = pipe->max_usage; 7198d020765SAl Viro struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), 7208d020765SAl Viro GFP_KERNEL); 7218d020765SAl Viro ssize_t ret; 7228d020765SAl Viro 7238d020765SAl Viro if (unlikely(!array)) 7248d020765SAl Viro return -ENOMEM; 7258d020765SAl Viro 7268d020765SAl Viro pipe_lock(pipe); 7278d020765SAl Viro 7288d020765SAl Viro splice_from_pipe_begin(&sd); 7298d020765SAl Viro while (sd.total_len) { 7308d020765SAl Viro struct iov_iter from; 731ec057595SLinus Torvalds unsigned int head, tail, mask; 7328d020765SAl Viro size_t left; 7338cefc107SDavid Howells int n; 7348d020765SAl Viro 7358d020765SAl Viro ret = splice_from_pipe_next(pipe, &sd); 7368d020765SAl Viro if (ret <= 0) 7378d020765SAl Viro break; 7388d020765SAl Viro 7396718b6f8SDavid Howells if (unlikely(nbufs < pipe->max_usage)) { 7408d020765SAl Viro kfree(array); 7416718b6f8SDavid Howells nbufs = pipe->max_usage; 7428d020765SAl Viro array = kcalloc(nbufs, sizeof(struct bio_vec), 7438d020765SAl Viro GFP_KERNEL); 7448d020765SAl Viro if (!array) { 7458d020765SAl Viro ret = -ENOMEM; 7468d020765SAl Viro break; 7478d020765SAl Viro } 7488d020765SAl Viro } 7498d020765SAl Viro 750ec057595SLinus Torvalds head = pipe->head; 751ec057595SLinus Torvalds tail = pipe->tail; 752ec057595SLinus Torvalds mask = pipe->ring_size - 1; 753ec057595SLinus Torvalds 7548d020765SAl Viro /* build the vector */ 7558d020765SAl Viro left = sd.total_len; 7560f1d344fSPavel Begunkov for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { 7578cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7588d020765SAl Viro size_t this_len = buf->len; 7598d020765SAl Viro 7600f1d344fSPavel Begunkov /* zero-length bvecs are not supported, skip them */ 7610f1d344fSPavel Begunkov if (!this_len) 7620f1d344fSPavel Begunkov continue; 7630f1d344fSPavel Begunkov this_len = min(this_len, left); 7648d020765SAl Viro 765fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 7668d020765SAl Viro if (unlikely(ret)) { 7678d020765SAl Viro if (ret == -ENODATA) 7688d020765SAl Viro ret = 0; 7698d020765SAl Viro goto done; 7708d020765SAl Viro } 7718d020765SAl Viro 772664e4078SChristoph Hellwig bvec_set_page(&array[n], buf->page, this_len, 773664e4078SChristoph Hellwig buf->offset); 7748d020765SAl Viro left -= this_len; 7750f1d344fSPavel Begunkov n++; 7768d020765SAl Viro } 7778d020765SAl Viro 778de4eda9dSAl Viro iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); 779abbb6589SChristoph Hellwig ret = vfs_iter_write(out, &from, &sd.pos, 0); 7808d020765SAl Viro if (ret <= 0) 7818d020765SAl Viro break; 7828d020765SAl Viro 7838d020765SAl Viro sd.num_spliced += ret; 7848d020765SAl Viro sd.total_len -= ret; 785dbe4e192SChristoph Hellwig *ppos = sd.pos; 7868d020765SAl Viro 7878d020765SAl Viro /* dismiss the fully eaten buffers, adjust the partial one */ 7888cefc107SDavid Howells tail = pipe->tail; 7898d020765SAl Viro while (ret) { 7908cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7918d020765SAl Viro if (ret >= buf->len) { 7928d020765SAl Viro ret -= buf->len; 7938d020765SAl Viro buf->len = 0; 794a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 7958cefc107SDavid Howells tail++; 7968cefc107SDavid Howells pipe->tail = tail; 7978d020765SAl Viro if (pipe->files) 7988d020765SAl Viro sd.need_wakeup = true; 7998d020765SAl Viro } else { 8008d020765SAl Viro buf->offset += ret; 8018d020765SAl Viro buf->len -= ret; 8028d020765SAl Viro ret = 0; 8038d020765SAl Viro } 8048d020765SAl Viro } 8058d020765SAl Viro } 8068d020765SAl Viro done: 8078d020765SAl Viro kfree(array); 8088d020765SAl Viro splice_from_pipe_end(pipe, &sd); 8098d020765SAl Viro 8108d020765SAl Viro pipe_unlock(pipe); 8118d020765SAl Viro 8128d020765SAl Viro if (sd.num_spliced) 8138d020765SAl Viro ret = sd.num_spliced; 8148d020765SAl Viro 8158d020765SAl Viro return ret; 8168d020765SAl Viro } 8178d020765SAl Viro 8188d020765SAl Viro EXPORT_SYMBOL(iter_file_splice_write); 8198d020765SAl Viro 82083f9135bSJens Axboe /** 82183f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 822932cc6d4SJens Axboe * @pipe: pipe to splice from 82383f9135bSJens Axboe * @out: socket to write to 824932cc6d4SJens Axboe * @ppos: position in @out 82583f9135bSJens Axboe * @len: number of bytes to splice 82683f9135bSJens Axboe * @flags: splice modifier flags 82783f9135bSJens Axboe * 828932cc6d4SJens Axboe * Description: 82983f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 83083f9135bSJens Axboe * is involved. 83183f9135bSJens Axboe * 83283f9135bSJens Axboe */ 8333a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 834cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8355274f052SJens Axboe { 83600522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8375274f052SJens Axboe } 8385274f052SJens Axboe 839059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 840a0f06780SJeff Garzik 84136e2c742SChristoph Hellwig static int warn_unsupported(struct file *file, const char *op) 84236e2c742SChristoph Hellwig { 84336e2c742SChristoph Hellwig pr_debug_ratelimited( 84436e2c742SChristoph Hellwig "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", 84536e2c742SChristoph Hellwig op, file, current->pid, current->comm); 84636e2c742SChristoph Hellwig return -EINVAL; 84736e2c742SChristoph Hellwig } 84836e2c742SChristoph Hellwig 84983f9135bSJens Axboe /* 85083f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 85183f9135bSJens Axboe */ 8523a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 853cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8545274f052SJens Axboe { 85536e2c742SChristoph Hellwig if (unlikely(!out->f_op->splice_write)) 85636e2c742SChristoph Hellwig return warn_unsupported(out, "write"); 85700c285d0SChristoph Hellwig return out->f_op->splice_write(pipe, out, ppos, len, flags); 8585274f052SJens Axboe } 8595274f052SJens Axboe 86083f9135bSJens Axboe /* 86183f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 86283f9135bSJens Axboe */ 863cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 864cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 865cbb7e577SJens Axboe unsigned int flags) 8665274f052SJens Axboe { 867313d64a3SAl Viro unsigned int p_space; 8685274f052SJens Axboe int ret; 8695274f052SJens Axboe 87049570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8715274f052SJens Axboe return -EBADF; 8725274f052SJens Axboe 873313d64a3SAl Viro /* Don't try to read more the pipe has space for. */ 874313d64a3SAl Viro p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); 875313d64a3SAl Viro len = min_t(size_t, len, p_space << PAGE_SHIFT); 876313d64a3SAl Viro 877cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 8785274f052SJens Axboe if (unlikely(ret < 0)) 8795274f052SJens Axboe return ret; 8805274f052SJens Axboe 88103cc0789SAl Viro if (unlikely(len > MAX_RW_COUNT)) 88203cc0789SAl Viro len = MAX_RW_COUNT; 88303cc0789SAl Viro 88436e2c742SChristoph Hellwig if (unlikely(!in->f_op->splice_read)) 88536e2c742SChristoph Hellwig return warn_unsupported(in, "read"); 8862bc01060SChristoph Hellwig return in->f_op->splice_read(in, ppos, pipe, len, flags); 8875274f052SJens Axboe } 8885274f052SJens Axboe 889932cc6d4SJens Axboe /** 890932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 891932cc6d4SJens Axboe * @in: file to splice from 892932cc6d4SJens Axboe * @sd: actor information on where to splice to 893932cc6d4SJens Axboe * @actor: handles the data splicing 894932cc6d4SJens Axboe * 895932cc6d4SJens Axboe * Description: 896932cc6d4SJens Axboe * This is a special case helper to splice directly between two 897932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 898932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 899932cc6d4SJens Axboe * that process. 900932cc6d4SJens Axboe * 901c66ab6faSJens Axboe */ 902c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 903c66ab6faSJens Axboe splice_direct_actor *actor) 904b92ce558SJens Axboe { 905b92ce558SJens Axboe struct pipe_inode_info *pipe; 906b92ce558SJens Axboe long ret, bytes; 907c66ab6faSJens Axboe size_t len; 9080ff28d9fSChristophe Leroy int i, flags, more; 909b92ce558SJens Axboe 910b92ce558SJens Axboe /* 91197ef77c5SJason A. Donenfeld * We require the input to be seekable, as we don't want to randomly 91297ef77c5SJason A. Donenfeld * drop data for eg socket -> socket splicing. Use the piped splicing 91397ef77c5SJason A. Donenfeld * for that! 914b92ce558SJens Axboe */ 91597ef77c5SJason A. Donenfeld if (unlikely(!(in->f_mode & FMODE_LSEEK))) 916b92ce558SJens Axboe return -EINVAL; 917b92ce558SJens Axboe 918b92ce558SJens Axboe /* 919b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 920b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 921b92ce558SJens Axboe */ 922b92ce558SJens Axboe pipe = current->splice_pipe; 92349570e9bSJens Axboe if (unlikely(!pipe)) { 9247bee130eSAl Viro pipe = alloc_pipe_info(); 925b92ce558SJens Axboe if (!pipe) 926b92ce558SJens Axboe return -ENOMEM; 927b92ce558SJens Axboe 928b92ce558SJens Axboe /* 929b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 93000522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 931b92ce558SJens Axboe * PIPE_READERS appropriately. 932b92ce558SJens Axboe */ 933b92ce558SJens Axboe pipe->readers = 1; 934b92ce558SJens Axboe 935b92ce558SJens Axboe current->splice_pipe = pipe; 936b92ce558SJens Axboe } 937b92ce558SJens Axboe 938b92ce558SJens Axboe /* 93973d62d83SIngo Molnar * Do the splice. 940b92ce558SJens Axboe */ 941b92ce558SJens Axboe bytes = 0; 942c66ab6faSJens Axboe len = sd->total_len; 943c66ab6faSJens Axboe flags = sd->flags; 944c66ab6faSJens Axboe 945c66ab6faSJens Axboe /* 946c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 947c66ab6faSJens Axboe */ 948c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 9490ff28d9fSChristophe Leroy more = sd->flags & SPLICE_F_MORE; 950b92ce558SJens Axboe 9518cefc107SDavid Howells WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); 95217614445SDarrick J. Wong 953b92ce558SJens Axboe while (len) { 95451a92c0fSJens Axboe size_t read_len; 955a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 956b92ce558SJens Axboe 957313d64a3SAl Viro ret = do_splice_to(in, &pos, pipe, len, flags); 95851a92c0fSJens Axboe if (unlikely(ret <= 0)) 959b92ce558SJens Axboe goto out_release; 960b92ce558SJens Axboe 961b92ce558SJens Axboe read_len = ret; 962c66ab6faSJens Axboe sd->total_len = read_len; 963b92ce558SJens Axboe 964b92ce558SJens Axboe /* 9650ff28d9fSChristophe Leroy * If more data is pending, set SPLICE_F_MORE 9660ff28d9fSChristophe Leroy * If this is the last data and SPLICE_F_MORE was not set 9670ff28d9fSChristophe Leroy * initially, clears it. 9680ff28d9fSChristophe Leroy */ 9690ff28d9fSChristophe Leroy if (read_len < len) 9700ff28d9fSChristophe Leroy sd->flags |= SPLICE_F_MORE; 9710ff28d9fSChristophe Leroy else if (!more) 9720ff28d9fSChristophe Leroy sd->flags &= ~SPLICE_F_MORE; 9730ff28d9fSChristophe Leroy /* 974b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 975b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 976b92ce558SJens Axboe * could get stuck data in the internal pipe: 977b92ce558SJens Axboe */ 978c66ab6faSJens Axboe ret = actor(pipe, sd); 979a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 980a82c53a0STom Zanussi sd->pos = prev_pos; 981b92ce558SJens Axboe goto out_release; 982a82c53a0STom Zanussi } 983b92ce558SJens Axboe 984b92ce558SJens Axboe bytes += ret; 985b92ce558SJens Axboe len -= ret; 986bcd4f3acSJens Axboe sd->pos = pos; 987b92ce558SJens Axboe 988a82c53a0STom Zanussi if (ret < read_len) { 989a82c53a0STom Zanussi sd->pos = prev_pos + ret; 99051a92c0fSJens Axboe goto out_release; 991b92ce558SJens Axboe } 992a82c53a0STom Zanussi } 993b92ce558SJens Axboe 9949e97198dSJens Axboe done: 9958cefc107SDavid Howells pipe->tail = pipe->head = 0; 9969e97198dSJens Axboe file_accessed(in); 997b92ce558SJens Axboe return bytes; 998b92ce558SJens Axboe 999b92ce558SJens Axboe out_release: 1000b92ce558SJens Axboe /* 1001b92ce558SJens Axboe * If we did an incomplete transfer we must release 1002b92ce558SJens Axboe * the pipe buffers in question: 1003b92ce558SJens Axboe */ 10048cefc107SDavid Howells for (i = 0; i < pipe->ring_size; i++) { 10058cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[i]; 1006b92ce558SJens Axboe 1007a779638cSMiklos Szeredi if (buf->ops) 1008a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 1009b92ce558SJens Axboe } 1010b92ce558SJens Axboe 10119e97198dSJens Axboe if (!bytes) 10129e97198dSJens Axboe bytes = ret; 1013b92ce558SJens Axboe 10149e97198dSJens Axboe goto done; 1015c66ab6faSJens Axboe } 1016c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1017c66ab6faSJens Axboe 1018c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1019c66ab6faSJens Axboe struct splice_desc *sd) 1020c66ab6faSJens Axboe { 10216a14b90bSJens Axboe struct file *file = sd->u.file; 1022c66ab6faSJens Axboe 10237995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 10242cb4b05eSChangli Gao sd->flags); 1025c66ab6faSJens Axboe } 1026c66ab6faSJens Axboe 1027932cc6d4SJens Axboe /** 1028932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1029932cc6d4SJens Axboe * @in: file to splice from 1030932cc6d4SJens Axboe * @ppos: input file offset 1031932cc6d4SJens Axboe * @out: file to splice to 1032acdb37c3SRandy Dunlap * @opos: output file offset 1033932cc6d4SJens Axboe * @len: number of bytes to splice 1034932cc6d4SJens Axboe * @flags: splice modifier flags 1035932cc6d4SJens Axboe * 1036932cc6d4SJens Axboe * Description: 1037932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1038932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1039932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1040932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1041932cc6d4SJens Axboe * 1042932cc6d4SJens Axboe */ 1043c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 10447995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1045c66ab6faSJens Axboe { 1046c66ab6faSJens Axboe struct splice_desc sd = { 1047c66ab6faSJens Axboe .len = len, 1048c66ab6faSJens Axboe .total_len = len, 1049c66ab6faSJens Axboe .flags = flags, 1050c66ab6faSJens Axboe .pos = *ppos, 10516a14b90bSJens Axboe .u.file = out, 10527995bd28SAl Viro .opos = opos, 1053c66ab6faSJens Axboe }; 105451a92c0fSJens Axboe long ret; 1055c66ab6faSJens Axboe 105618c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 105718c67cb9SAl Viro return -EBADF; 105818c67cb9SAl Viro 105918c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 106018c67cb9SAl Viro return -EINVAL; 106118c67cb9SAl Viro 106218c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 106318c67cb9SAl Viro if (unlikely(ret < 0)) 106418c67cb9SAl Viro return ret; 106518c67cb9SAl Viro 1066c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 106751a92c0fSJens Axboe if (ret > 0) 1068a82c53a0STom Zanussi *ppos = sd.pos; 106951a92c0fSJens Axboe 1070c66ab6faSJens Axboe return ret; 1071b92ce558SJens Axboe } 10721c118596SMiklos Szeredi EXPORT_SYMBOL(do_splice_direct); 1073b92ce558SJens Axboe 10748924feffSAl Viro static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) 10758924feffSAl Viro { 107652bce911SLinus Torvalds for (;;) { 107752bce911SLinus Torvalds if (unlikely(!pipe->readers)) { 107852bce911SLinus Torvalds send_sig(SIGPIPE, current, 0); 107952bce911SLinus Torvalds return -EPIPE; 108052bce911SLinus Torvalds } 10816718b6f8SDavid Howells if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 108252bce911SLinus Torvalds return 0; 10838924feffSAl Viro if (flags & SPLICE_F_NONBLOCK) 10848924feffSAl Viro return -EAGAIN; 10858924feffSAl Viro if (signal_pending(current)) 10868924feffSAl Viro return -ERESTARTSYS; 1087472e5b05SLinus Torvalds pipe_wait_writable(pipe); 10888924feffSAl Viro } 10898924feffSAl Viro } 10908924feffSAl Viro 10917c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 10927c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 10937c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1094ddac0d39SJens Axboe 1095b964bf53SAl Viro long splice_file_to_pipe(struct file *in, 1096faa97c48SAl Viro struct pipe_inode_info *opipe, 1097faa97c48SAl Viro loff_t *offset, 1098faa97c48SAl Viro size_t len, unsigned int flags) 1099faa97c48SAl Viro { 1100faa97c48SAl Viro long ret; 1101faa97c48SAl Viro 1102faa97c48SAl Viro pipe_lock(opipe); 1103faa97c48SAl Viro ret = wait_for_space(opipe, flags); 1104faa97c48SAl Viro if (!ret) 1105faa97c48SAl Viro ret = do_splice_to(in, offset, opipe, len, flags); 1106faa97c48SAl Viro pipe_unlock(opipe); 1107faa97c48SAl Viro if (ret > 0) 1108faa97c48SAl Viro wakeup_pipe_readers(opipe); 1109faa97c48SAl Viro return ret; 1110faa97c48SAl Viro } 1111faa97c48SAl Viro 1112ddac0d39SJens Axboe /* 111383f9135bSJens Axboe * Determine where to splice to/from. 111483f9135bSJens Axboe */ 1115ee6e00c8SJens Axboe long do_splice(struct file *in, loff_t *off_in, struct file *out, 1116ee6e00c8SJens Axboe loff_t *off_out, size_t len, unsigned int flags) 11175274f052SJens Axboe { 11187c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 11197c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 11207995bd28SAl Viro loff_t offset; 1121a4514ebdSJens Axboe long ret; 11225274f052SJens Axboe 112390da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 112490da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 112590da2e3fSPavel Begunkov return -EBADF; 112690da2e3fSPavel Begunkov 1127c73be61cSDavid Howells ipipe = get_pipe_info(in, true); 1128c73be61cSDavid Howells opipe = get_pipe_info(out, true); 11297c77f0b3SMiklos Szeredi 11307c77f0b3SMiklos Szeredi if (ipipe && opipe) { 11317c77f0b3SMiklos Szeredi if (off_in || off_out) 11327c77f0b3SMiklos Szeredi return -ESPIPE; 11337c77f0b3SMiklos Szeredi 11347c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 11357c77f0b3SMiklos Szeredi if (ipipe == opipe) 11367c77f0b3SMiklos Szeredi return -EINVAL; 11377c77f0b3SMiklos Szeredi 1138ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1139ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1140ee5e0011SSlavomir Kaslev 11417c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 11427c77f0b3SMiklos Szeredi } 11437c77f0b3SMiklos Szeredi 11447c77f0b3SMiklos Szeredi if (ipipe) { 1145529565dcSIngo Molnar if (off_in) 1146529565dcSIngo Molnar return -ESPIPE; 1147b92ce558SJens Axboe if (off_out) { 114819c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1149b92ce558SJens Axboe return -EINVAL; 1150ee6e00c8SJens Axboe offset = *off_out; 11517995bd28SAl Viro } else { 11527995bd28SAl Viro offset = out->f_pos; 11537995bd28SAl Viro } 1154529565dcSIngo Molnar 115518c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 115618c67cb9SAl Viro return -EINVAL; 115718c67cb9SAl Viro 115818c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 115918c67cb9SAl Viro if (unlikely(ret < 0)) 116018c67cb9SAl Viro return ret; 116118c67cb9SAl Viro 1162ee5e0011SSlavomir Kaslev if (in->f_flags & O_NONBLOCK) 1163ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1164ee5e0011SSlavomir Kaslev 1165500368f7SAl Viro file_start_write(out); 11667995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1167500368f7SAl Viro file_end_write(out); 1168a4514ebdSJens Axboe 1169*983652c6SChung-Chiang Cheng if (ret > 0) 1170*983652c6SChung-Chiang Cheng fsnotify_modify(out); 1171*983652c6SChung-Chiang Cheng 11727995bd28SAl Viro if (!off_out) 11737995bd28SAl Viro out->f_pos = offset; 1174ee6e00c8SJens Axboe else 1175ee6e00c8SJens Axboe *off_out = offset; 1176a4514ebdSJens Axboe 1177a4514ebdSJens Axboe return ret; 1178529565dcSIngo Molnar } 11795274f052SJens Axboe 11807c77f0b3SMiklos Szeredi if (opipe) { 1181529565dcSIngo Molnar if (off_out) 1182529565dcSIngo Molnar return -ESPIPE; 1183b92ce558SJens Axboe if (off_in) { 118419c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1185b92ce558SJens Axboe return -EINVAL; 1186ee6e00c8SJens Axboe offset = *off_in; 11877995bd28SAl Viro } else { 11887995bd28SAl Viro offset = in->f_pos; 11897995bd28SAl Viro } 1190529565dcSIngo Molnar 1191ee5e0011SSlavomir Kaslev if (out->f_flags & O_NONBLOCK) 1192ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1193ee5e0011SSlavomir Kaslev 1194faa97c48SAl Viro ret = splice_file_to_pipe(in, opipe, &offset, len, flags); 1195*983652c6SChung-Chiang Cheng 1196*983652c6SChung-Chiang Cheng if (ret > 0) 1197*983652c6SChung-Chiang Cheng fsnotify_access(in); 1198*983652c6SChung-Chiang Cheng 11997995bd28SAl Viro if (!off_in) 12007995bd28SAl Viro in->f_pos = offset; 1201ee6e00c8SJens Axboe else 1202ee6e00c8SJens Axboe *off_in = offset; 1203a4514ebdSJens Axboe 1204a4514ebdSJens Axboe return ret; 1205529565dcSIngo Molnar } 12065274f052SJens Axboe 12075274f052SJens Axboe return -EINVAL; 12085274f052SJens Axboe } 12095274f052SJens Axboe 1210ee6e00c8SJens Axboe static long __do_splice(struct file *in, loff_t __user *off_in, 1211ee6e00c8SJens Axboe struct file *out, loff_t __user *off_out, 1212ee6e00c8SJens Axboe size_t len, unsigned int flags) 1213ee6e00c8SJens Axboe { 1214ee6e00c8SJens Axboe struct pipe_inode_info *ipipe; 1215ee6e00c8SJens Axboe struct pipe_inode_info *opipe; 1216ee6e00c8SJens Axboe loff_t offset, *__off_in = NULL, *__off_out = NULL; 1217ee6e00c8SJens Axboe long ret; 1218ee6e00c8SJens Axboe 1219ee6e00c8SJens Axboe ipipe = get_pipe_info(in, true); 1220ee6e00c8SJens Axboe opipe = get_pipe_info(out, true); 1221ee6e00c8SJens Axboe 1222ee6e00c8SJens Axboe if (ipipe && off_in) 1223ee6e00c8SJens Axboe return -ESPIPE; 1224ee6e00c8SJens Axboe if (opipe && off_out) 1225ee6e00c8SJens Axboe return -ESPIPE; 1226ee6e00c8SJens Axboe 1227ee6e00c8SJens Axboe if (off_out) { 1228ee6e00c8SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1229ee6e00c8SJens Axboe return -EFAULT; 1230ee6e00c8SJens Axboe __off_out = &offset; 1231ee6e00c8SJens Axboe } 1232ee6e00c8SJens Axboe if (off_in) { 1233ee6e00c8SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1234ee6e00c8SJens Axboe return -EFAULT; 1235ee6e00c8SJens Axboe __off_in = &offset; 1236ee6e00c8SJens Axboe } 1237ee6e00c8SJens Axboe 1238ee6e00c8SJens Axboe ret = do_splice(in, __off_in, out, __off_out, len, flags); 1239ee6e00c8SJens Axboe if (ret < 0) 1240ee6e00c8SJens Axboe return ret; 1241ee6e00c8SJens Axboe 1242ee6e00c8SJens Axboe if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) 1243ee6e00c8SJens Axboe return -EFAULT; 1244ee6e00c8SJens Axboe if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) 1245ee6e00c8SJens Axboe return -EFAULT; 1246ee6e00c8SJens Axboe 1247ee6e00c8SJens Axboe return ret; 1248ee6e00c8SJens Axboe } 1249ee6e00c8SJens Axboe 125079fddc4eSAl Viro static int iter_to_pipe(struct iov_iter *from, 125179fddc4eSAl Viro struct pipe_inode_info *pipe, 125279fddc4eSAl Viro unsigned flags) 1253912d35f8SJens Axboe { 125479fddc4eSAl Viro struct pipe_buffer buf = { 125579fddc4eSAl Viro .ops = &user_page_pipe_buf_ops, 125679fddc4eSAl Viro .flags = flags 125779fddc4eSAl Viro }; 125879fddc4eSAl Viro size_t total = 0; 125979fddc4eSAl Viro int ret = 0; 126079fddc4eSAl Viro 12617d690c15SAl Viro while (iov_iter_count(from)) { 126279fddc4eSAl Viro struct page *pages[16]; 12637d690c15SAl Viro ssize_t left; 1264db85a9ebSAl Viro size_t start; 12657d690c15SAl Viro int i, n; 1266912d35f8SJens Axboe 12677d690c15SAl Viro left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); 12687d690c15SAl Viro if (left <= 0) { 12697d690c15SAl Viro ret = left; 127079fddc4eSAl Viro break; 127179fddc4eSAl Viro } 1272912d35f8SJens Axboe 12737d690c15SAl Viro n = DIV_ROUND_UP(left + start, PAGE_SIZE); 12747d690c15SAl Viro for (i = 0; i < n; i++) { 12757d690c15SAl Viro int size = min_t(int, left, PAGE_SIZE - start); 12767d690c15SAl Viro 12777d690c15SAl Viro buf.page = pages[i]; 127879fddc4eSAl Viro buf.offset = start; 127979fddc4eSAl Viro buf.len = size; 128079fddc4eSAl Viro ret = add_to_pipe(pipe, &buf); 128179fddc4eSAl Viro if (unlikely(ret < 0)) { 12827d690c15SAl Viro iov_iter_revert(from, left); 12837d690c15SAl Viro // this one got dropped by add_to_pipe() 12847d690c15SAl Viro while (++i < n) 12857d690c15SAl Viro put_page(pages[i]); 12867d690c15SAl Viro goto out; 12877d690c15SAl Viro } 128879fddc4eSAl Viro total += ret; 12897d690c15SAl Viro left -= size; 12907d690c15SAl Viro start = 0; 1291912d35f8SJens Axboe } 1292912d35f8SJens Axboe } 12937d690c15SAl Viro out: 129479fddc4eSAl Viro return total ? total : ret; 1295912d35f8SJens Axboe } 1296912d35f8SJens Axboe 12976a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12986a14b90bSJens Axboe struct splice_desc *sd) 12996a14b90bSJens Axboe { 13006130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 13016130f531SAl Viro return n == sd->len ? n : -EFAULT; 13026a14b90bSJens Axboe } 13036a14b90bSJens Axboe 13046a14b90bSJens Axboe /* 13056a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13066a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13076a14b90bSJens Axboe */ 130887a3002aSAl Viro static long vmsplice_to_user(struct file *file, struct iov_iter *iter, 130987a3002aSAl Viro unsigned int flags) 13106a14b90bSJens Axboe { 1311c73be61cSDavid Howells struct pipe_inode_info *pipe = get_pipe_info(file, true); 131287a3002aSAl Viro struct splice_desc sd = { 131387a3002aSAl Viro .total_len = iov_iter_count(iter), 131487a3002aSAl Viro .flags = flags, 131587a3002aSAl Viro .u.data = iter 131687a3002aSAl Viro }; 131787a3002aSAl Viro long ret = 0; 13186a14b90bSJens Axboe 13196a14b90bSJens Axboe if (!pipe) 13206a14b90bSJens Axboe return -EBADF; 13216a14b90bSJens Axboe 1322345995faSAl Viro if (sd.total_len) { 13236130f531SAl Viro pipe_lock(pipe); 13246130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 132561e0d47cSMiklos Szeredi pipe_unlock(pipe); 1326345995faSAl Viro } 13276a14b90bSJens Axboe 13286a14b90bSJens Axboe return ret; 13296a14b90bSJens Axboe } 13306a14b90bSJens Axboe 1331912d35f8SJens Axboe /* 1332912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1333912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1334912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1335912d35f8SJens Axboe */ 133687a3002aSAl Viro static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, 133787a3002aSAl Viro unsigned int flags) 1338912d35f8SJens Axboe { 1339ddac0d39SJens Axboe struct pipe_inode_info *pipe; 134087a3002aSAl Viro long ret = 0; 134179fddc4eSAl Viro unsigned buf_flag = 0; 134279fddc4eSAl Viro 134379fddc4eSAl Viro if (flags & SPLICE_F_GIFT) 134479fddc4eSAl Viro buf_flag = PIPE_BUF_FLAG_GIFT; 1345912d35f8SJens Axboe 1346c73be61cSDavid Howells pipe = get_pipe_info(file, true); 1347ddac0d39SJens Axboe if (!pipe) 1348912d35f8SJens Axboe return -EBADF; 1349912d35f8SJens Axboe 13508924feffSAl Viro pipe_lock(pipe); 13518924feffSAl Viro ret = wait_for_space(pipe, flags); 135279fddc4eSAl Viro if (!ret) 135387a3002aSAl Viro ret = iter_to_pipe(iter, pipe, buf_flag); 13548924feffSAl Viro pipe_unlock(pipe); 13558924feffSAl Viro if (ret > 0) 13568924feffSAl Viro wakeup_pipe_readers(pipe); 135735f3d14dSJens Axboe return ret; 1358912d35f8SJens Axboe } 1359912d35f8SJens Axboe 136087a3002aSAl Viro static int vmsplice_type(struct fd f, int *type) 136187a3002aSAl Viro { 136287a3002aSAl Viro if (!f.file) 136387a3002aSAl Viro return -EBADF; 136487a3002aSAl Viro if (f.file->f_mode & FMODE_WRITE) { 1365de4eda9dSAl Viro *type = ITER_SOURCE; 136687a3002aSAl Viro } else if (f.file->f_mode & FMODE_READ) { 1367de4eda9dSAl Viro *type = ITER_DEST; 136887a3002aSAl Viro } else { 136987a3002aSAl Viro fdput(f); 137087a3002aSAl Viro return -EBADF; 137187a3002aSAl Viro } 137287a3002aSAl Viro return 0; 137387a3002aSAl Viro } 137487a3002aSAl Viro 13756a14b90bSJens Axboe /* 13766a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 13776a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 13786a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 13796a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 13806a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 13816a14b90bSJens Axboe * solutions for that: 13826a14b90bSJens Axboe * 13836a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 13846a14b90bSJens Axboe * do a regular read() on the buffer anyway. 13856a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 13866a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 13876a14b90bSJens Axboe * 13886a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 13896a14b90bSJens Axboe * 13906a14b90bSJens Axboe */ 139187a3002aSAl Viro SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, 139230cfe4efSDominik Brodowski unsigned long, nr_segs, unsigned int, flags) 139330cfe4efSDominik Brodowski { 139487a3002aSAl Viro struct iovec iovstack[UIO_FASTIOV]; 139587a3002aSAl Viro struct iovec *iov = iovstack; 139687a3002aSAl Viro struct iov_iter iter; 139787e5e6daSJens Axboe ssize_t error; 139887a3002aSAl Viro struct fd f; 139987a3002aSAl Viro int type; 140087a3002aSAl Viro 1401598b3cecSChristoph Hellwig if (unlikely(flags & ~SPLICE_F_ALL)) 1402598b3cecSChristoph Hellwig return -EINVAL; 1403598b3cecSChristoph Hellwig 140487a3002aSAl Viro f = fdget(fd); 140587a3002aSAl Viro error = vmsplice_type(f, &type); 140687a3002aSAl Viro if (error) 140787a3002aSAl Viro return error; 140887a3002aSAl Viro 140987a3002aSAl Viro error = import_iovec(type, uiov, nr_segs, 141087a3002aSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 1411598b3cecSChristoph Hellwig if (error < 0) 1412598b3cecSChristoph Hellwig goto out_fdput; 1413598b3cecSChristoph Hellwig 1414598b3cecSChristoph Hellwig if (!iov_iter_count(&iter)) 1415598b3cecSChristoph Hellwig error = 0; 1416de4eda9dSAl Viro else if (type == ITER_SOURCE) 1417598b3cecSChristoph Hellwig error = vmsplice_to_pipe(f.file, &iter, flags); 1418598b3cecSChristoph Hellwig else 1419598b3cecSChristoph Hellwig error = vmsplice_to_user(f.file, &iter, flags); 1420598b3cecSChristoph Hellwig 142187a3002aSAl Viro kfree(iov); 1422598b3cecSChristoph Hellwig out_fdput: 142387a3002aSAl Viro fdput(f); 142487a3002aSAl Viro return error; 142530cfe4efSDominik Brodowski } 142630cfe4efSDominik Brodowski 1427836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1428836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1429836f92adSHeiko Carstens size_t, len, unsigned int, flags) 14305274f052SJens Axboe { 14312903ff01SAl Viro struct fd in, out; 14325274f052SJens Axboe long error; 14335274f052SJens Axboe 14345274f052SJens Axboe if (unlikely(!len)) 14355274f052SJens Axboe return 0; 14365274f052SJens Axboe 14373d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 14383d6ea290SAl Viro return -EINVAL; 14393d6ea290SAl Viro 14405274f052SJens Axboe error = -EBADF; 14412903ff01SAl Viro in = fdget(fd_in); 14422903ff01SAl Viro if (in.file) { 14432903ff01SAl Viro out = fdget(fd_out); 14442903ff01SAl Viro if (out.file) { 1445ee6e00c8SJens Axboe error = __do_splice(in.file, off_in, out.file, off_out, 1446529565dcSIngo Molnar len, flags); 14472903ff01SAl Viro fdput(out); 14485274f052SJens Axboe } 14492903ff01SAl Viro fdput(in); 14505274f052SJens Axboe } 14515274f052SJens Axboe return error; 14525274f052SJens Axboe } 145370524490SJens Axboe 145470524490SJens Axboe /* 1455aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1456aadd06e5SJens Axboe * return an appropriate error. 1457aadd06e5SJens Axboe */ 14587c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1459aadd06e5SJens Axboe { 1460aadd06e5SJens Axboe int ret; 1461aadd06e5SJens Axboe 1462aadd06e5SJens Axboe /* 14638cefc107SDavid Howells * Check the pipe occupancy without the inode lock first. This function 1464aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1465aadd06e5SJens Axboe */ 14668cefc107SDavid Howells if (!pipe_empty(pipe->head, pipe->tail)) 1467aadd06e5SJens Axboe return 0; 1468aadd06e5SJens Axboe 1469aadd06e5SJens Axboe ret = 0; 147061e0d47cSMiklos Szeredi pipe_lock(pipe); 1471aadd06e5SJens Axboe 14728cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 1473aadd06e5SJens Axboe if (signal_pending(current)) { 1474aadd06e5SJens Axboe ret = -ERESTARTSYS; 1475aadd06e5SJens Axboe break; 1476aadd06e5SJens Axboe } 1477aadd06e5SJens Axboe if (!pipe->writers) 1478aadd06e5SJens Axboe break; 1479aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1480aadd06e5SJens Axboe ret = -EAGAIN; 1481aadd06e5SJens Axboe break; 1482aadd06e5SJens Axboe } 1483472e5b05SLinus Torvalds pipe_wait_readable(pipe); 1484aadd06e5SJens Axboe } 1485aadd06e5SJens Axboe 148661e0d47cSMiklos Szeredi pipe_unlock(pipe); 1487aadd06e5SJens Axboe return ret; 1488aadd06e5SJens Axboe } 1489aadd06e5SJens Axboe 1490aadd06e5SJens Axboe /* 1491aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1492aadd06e5SJens Axboe * return an appropriate error. 1493aadd06e5SJens Axboe */ 14947c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1495aadd06e5SJens Axboe { 1496aadd06e5SJens Axboe int ret; 1497aadd06e5SJens Axboe 1498aadd06e5SJens Axboe /* 14998cefc107SDavid Howells * Check pipe occupancy without the inode lock first. This function 1500aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1501aadd06e5SJens Axboe */ 1502566d1362STetsuo Handa if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 1503aadd06e5SJens Axboe return 0; 1504aadd06e5SJens Axboe 1505aadd06e5SJens Axboe ret = 0; 150661e0d47cSMiklos Szeredi pipe_lock(pipe); 1507aadd06e5SJens Axboe 15086718b6f8SDavid Howells while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 1509aadd06e5SJens Axboe if (!pipe->readers) { 1510aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1511aadd06e5SJens Axboe ret = -EPIPE; 1512aadd06e5SJens Axboe break; 1513aadd06e5SJens Axboe } 1514aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1515aadd06e5SJens Axboe ret = -EAGAIN; 1516aadd06e5SJens Axboe break; 1517aadd06e5SJens Axboe } 1518aadd06e5SJens Axboe if (signal_pending(current)) { 1519aadd06e5SJens Axboe ret = -ERESTARTSYS; 1520aadd06e5SJens Axboe break; 1521aadd06e5SJens Axboe } 1522472e5b05SLinus Torvalds pipe_wait_writable(pipe); 1523aadd06e5SJens Axboe } 1524aadd06e5SJens Axboe 152561e0d47cSMiklos Szeredi pipe_unlock(pipe); 1526aadd06e5SJens Axboe return ret; 1527aadd06e5SJens Axboe } 1528aadd06e5SJens Axboe 1529aadd06e5SJens Axboe /* 15307c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 15317c77f0b3SMiklos Szeredi */ 15327c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 15337c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 15347c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 15357c77f0b3SMiklos Szeredi { 15367c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 15378cefc107SDavid Howells unsigned int i_head, o_head; 15388cefc107SDavid Howells unsigned int i_tail, o_tail; 15398cefc107SDavid Howells unsigned int i_mask, o_mask; 15408cefc107SDavid Howells int ret = 0; 15417c77f0b3SMiklos Szeredi bool input_wakeup = false; 15427c77f0b3SMiklos Szeredi 15437c77f0b3SMiklos Szeredi 15447c77f0b3SMiklos Szeredi retry: 15457c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 15467c77f0b3SMiklos Szeredi if (ret) 15477c77f0b3SMiklos Szeredi return ret; 15487c77f0b3SMiklos Szeredi 15497c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 15507c77f0b3SMiklos Szeredi if (ret) 15517c77f0b3SMiklos Szeredi return ret; 15527c77f0b3SMiklos Szeredi 15537c77f0b3SMiklos Szeredi /* 15547c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 15557c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 15567c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 15577c77f0b3SMiklos Szeredi */ 15587c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 15597c77f0b3SMiklos Szeredi 15608cefc107SDavid Howells i_tail = ipipe->tail; 15618cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 15628cefc107SDavid Howells o_head = opipe->head; 15638cefc107SDavid Howells o_mask = opipe->ring_size - 1; 15648cefc107SDavid Howells 15657c77f0b3SMiklos Szeredi do { 15668cefc107SDavid Howells size_t o_len; 15678cefc107SDavid Howells 15687c77f0b3SMiklos Szeredi if (!opipe->readers) { 15697c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 15707c77f0b3SMiklos Szeredi if (!ret) 15717c77f0b3SMiklos Szeredi ret = -EPIPE; 15727c77f0b3SMiklos Szeredi break; 15737c77f0b3SMiklos Szeredi } 15747c77f0b3SMiklos Szeredi 15758cefc107SDavid Howells i_head = ipipe->head; 15768cefc107SDavid Howells o_tail = opipe->tail; 15778cefc107SDavid Howells 15788cefc107SDavid Howells if (pipe_empty(i_head, i_tail) && !ipipe->writers) 15797c77f0b3SMiklos Szeredi break; 15807c77f0b3SMiklos Szeredi 15817c77f0b3SMiklos Szeredi /* 15827c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 15837c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 15847c77f0b3SMiklos Szeredi */ 15858cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 15866718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) { 15877c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 15887c77f0b3SMiklos Szeredi if (ret) 15897c77f0b3SMiklos Szeredi break; 15907c77f0b3SMiklos Szeredi 15917c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 15927c77f0b3SMiklos Szeredi ret = -EAGAIN; 15937c77f0b3SMiklos Szeredi break; 15947c77f0b3SMiklos Szeredi } 15957c77f0b3SMiklos Szeredi 15967c77f0b3SMiklos Szeredi /* 15977c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 15987c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 15997c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 16007c77f0b3SMiklos Szeredi */ 16017c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16027c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16037c77f0b3SMiklos Szeredi goto retry; 16047c77f0b3SMiklos Szeredi } 16057c77f0b3SMiklos Szeredi 16068cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 16078cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 16087c77f0b3SMiklos Szeredi 16097c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 16107c77f0b3SMiklos Szeredi /* 16117c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 16127c77f0b3SMiklos Szeredi */ 16137c77f0b3SMiklos Szeredi *obuf = *ibuf; 16147c77f0b3SMiklos Szeredi ibuf->ops = NULL; 16158cefc107SDavid Howells i_tail++; 16168cefc107SDavid Howells ipipe->tail = i_tail; 16177c77f0b3SMiklos Szeredi input_wakeup = true; 16188cefc107SDavid Howells o_len = obuf->len; 16198cefc107SDavid Howells o_head++; 16208cefc107SDavid Howells opipe->head = o_head; 16217c77f0b3SMiklos Szeredi } else { 16227c77f0b3SMiklos Szeredi /* 16237c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 16247c77f0b3SMiklos Szeredi * so we can copy the contents over. 16257c77f0b3SMiklos Szeredi */ 162615fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 162715fab63eSMatthew Wilcox if (ret == 0) 162815fab63eSMatthew Wilcox ret = -EFAULT; 162915fab63eSMatthew Wilcox break; 163015fab63eSMatthew Wilcox } 16317c77f0b3SMiklos Szeredi *obuf = *ibuf; 16327c77f0b3SMiklos Szeredi 16337c77f0b3SMiklos Szeredi /* 1634f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flags, we need to 16357c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 16367c77f0b3SMiklos Szeredi */ 16377c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1638f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1639a0ce2f0aSJann Horn 16407c77f0b3SMiklos Szeredi obuf->len = len; 16418cefc107SDavid Howells ibuf->offset += len; 16428cefc107SDavid Howells ibuf->len -= len; 16438cefc107SDavid Howells o_len = len; 16448cefc107SDavid Howells o_head++; 16458cefc107SDavid Howells opipe->head = o_head; 16467c77f0b3SMiklos Szeredi } 16478cefc107SDavid Howells ret += o_len; 16488cefc107SDavid Howells len -= o_len; 16497c77f0b3SMiklos Szeredi } while (len); 16507c77f0b3SMiklos Szeredi 16517c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16527c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16537c77f0b3SMiklos Szeredi 16547c77f0b3SMiklos Szeredi /* 16557c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 16567c77f0b3SMiklos Szeredi */ 1657825cdcb1SNamhyung Kim if (ret > 0) 1658825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1659825cdcb1SNamhyung Kim 16607c77f0b3SMiklos Szeredi if (input_wakeup) 16617c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 16627c77f0b3SMiklos Szeredi 16637c77f0b3SMiklos Szeredi return ret; 16647c77f0b3SMiklos Szeredi } 16657c77f0b3SMiklos Szeredi 16667c77f0b3SMiklos Szeredi /* 166770524490SJens Axboe * Link contents of ipipe to opipe. 166870524490SJens Axboe */ 166970524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 167070524490SJens Axboe struct pipe_inode_info *opipe, 167170524490SJens Axboe size_t len, unsigned int flags) 167270524490SJens Axboe { 167370524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 16748cefc107SDavid Howells unsigned int i_head, o_head; 16758cefc107SDavid Howells unsigned int i_tail, o_tail; 16768cefc107SDavid Howells unsigned int i_mask, o_mask; 16778cefc107SDavid Howells int ret = 0; 167870524490SJens Axboe 167970524490SJens Axboe /* 168070524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 168161e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 168270524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 168370524490SJens Axboe */ 168461e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 168570524490SJens Axboe 16868cefc107SDavid Howells i_tail = ipipe->tail; 16878cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 16888cefc107SDavid Howells o_head = opipe->head; 16898cefc107SDavid Howells o_mask = opipe->ring_size - 1; 16908cefc107SDavid Howells 1691aadd06e5SJens Axboe do { 169270524490SJens Axboe if (!opipe->readers) { 169370524490SJens Axboe send_sig(SIGPIPE, current, 0); 169470524490SJens Axboe if (!ret) 169570524490SJens Axboe ret = -EPIPE; 169670524490SJens Axboe break; 169770524490SJens Axboe } 169870524490SJens Axboe 16998cefc107SDavid Howells i_head = ipipe->head; 17008cefc107SDavid Howells o_tail = opipe->tail; 17018cefc107SDavid Howells 170270524490SJens Axboe /* 17038cefc107SDavid Howells * If we have iterated all input buffers or run out of 1704aadd06e5SJens Axboe * output room, break. 170570524490SJens Axboe */ 17068cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 17076718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) 1708aadd06e5SJens Axboe break; 1709aadd06e5SJens Axboe 17108cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 17118cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 171270524490SJens Axboe 171370524490SJens Axboe /* 171470524490SJens Axboe * Get a reference to this pipe buffer, 171570524490SJens Axboe * so we can copy the contents over. 171670524490SJens Axboe */ 171715fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 171815fab63eSMatthew Wilcox if (ret == 0) 171915fab63eSMatthew Wilcox ret = -EFAULT; 172015fab63eSMatthew Wilcox break; 172115fab63eSMatthew Wilcox } 172270524490SJens Axboe 172370524490SJens Axboe *obuf = *ibuf; 172470524490SJens Axboe 17257afa6fd0SJens Axboe /* 1726f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flag, we need to prevent 1727f6dd9755SChristoph Hellwig * multiple steals of this page. 17287afa6fd0SJens Axboe */ 17297afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1730f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1731a0ce2f0aSJann Horn 173270524490SJens Axboe if (obuf->len > len) 173370524490SJens Axboe obuf->len = len; 173470524490SJens Axboe ret += obuf->len; 173570524490SJens Axboe len -= obuf->len; 17368cefc107SDavid Howells 17378cefc107SDavid Howells o_head++; 17388cefc107SDavid Howells opipe->head = o_head; 17398cefc107SDavid Howells i_tail++; 1740aadd06e5SJens Axboe } while (len); 174170524490SJens Axboe 174261e0d47cSMiklos Szeredi pipe_unlock(ipipe); 174361e0d47cSMiklos Szeredi pipe_unlock(opipe); 174470524490SJens Axboe 1745aadd06e5SJens Axboe /* 1746aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1747aadd06e5SJens Axboe */ 1748825cdcb1SNamhyung Kim if (ret > 0) 1749825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 175070524490SJens Axboe 175170524490SJens Axboe return ret; 175270524490SJens Axboe } 175370524490SJens Axboe 175470524490SJens Axboe /* 175570524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 175670524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 175770524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 175870524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 175970524490SJens Axboe */ 17609dafdfc2SPavel Begunkov long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) 176170524490SJens Axboe { 1762c73be61cSDavid Howells struct pipe_inode_info *ipipe = get_pipe_info(in, true); 1763c73be61cSDavid Howells struct pipe_inode_info *opipe = get_pipe_info(out, true); 1764aadd06e5SJens Axboe int ret = -EINVAL; 176570524490SJens Axboe 176690da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 176790da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 176890da2e3fSPavel Begunkov return -EBADF; 176990da2e3fSPavel Begunkov 177070524490SJens Axboe /* 1771aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1772aadd06e5SJens Axboe * copying the data. 177370524490SJens Axboe */ 1774aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1775ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1776ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1777ee5e0011SSlavomir Kaslev 1778aadd06e5SJens Axboe /* 1779aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1780aadd06e5SJens Axboe * ordering doesn't really matter. 1781aadd06e5SJens Axboe */ 17827c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1783aadd06e5SJens Axboe if (!ret) { 17847c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 178502cf01aeSJens Axboe if (!ret) 1786aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1787aadd06e5SJens Axboe } 1788aadd06e5SJens Axboe } 178970524490SJens Axboe 1790aadd06e5SJens Axboe return ret; 179170524490SJens Axboe } 179270524490SJens Axboe 1793836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 179470524490SJens Axboe { 179590da2e3fSPavel Begunkov struct fd in, out; 17962903ff01SAl Viro int error; 179770524490SJens Axboe 17983d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 17993d6ea290SAl Viro return -EINVAL; 18003d6ea290SAl Viro 180170524490SJens Axboe if (unlikely(!len)) 180270524490SJens Axboe return 0; 180370524490SJens Axboe 180470524490SJens Axboe error = -EBADF; 18052903ff01SAl Viro in = fdget(fdin); 18062903ff01SAl Viro if (in.file) { 180790da2e3fSPavel Begunkov out = fdget(fdout); 18082903ff01SAl Viro if (out.file) { 180990da2e3fSPavel Begunkov error = do_tee(in.file, out.file, len, flags); 18102903ff01SAl Viro fdput(out); 181170524490SJens Axboe } 18122903ff01SAl Viro fdput(in); 181370524490SJens Axboe } 181470524490SJens Axboe 181570524490SJens Axboe return error; 181670524490SJens Axboe } 1817