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> 33983652c6SChung-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 /* 420f99fc51SJens Axboe * Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to 430f99fc51SJens Axboe * indicate they support non-blocking reads or writes, we must clear it 440f99fc51SJens Axboe * here if set to avoid blocking other users of this pipe if splice is 450f99fc51SJens Axboe * being done on it. 460f99fc51SJens Axboe */ 470f99fc51SJens Axboe static noinline void noinline pipe_clear_nowait(struct file *file) 480f99fc51SJens Axboe { 490f99fc51SJens Axboe fmode_t fmode = READ_ONCE(file->f_mode); 500f99fc51SJens Axboe 510f99fc51SJens Axboe do { 520f99fc51SJens Axboe if (!(fmode & FMODE_NOWAIT)) 530f99fc51SJens Axboe break; 540f99fc51SJens Axboe } while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT)); 550f99fc51SJens Axboe } 560f99fc51SJens Axboe 570f99fc51SJens Axboe /* 5883f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 5983f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 6083f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 6183f9135bSJens Axboe * attempt to reuse this page for another destination. 6283f9135bSJens Axboe */ 63c928f642SChristoph Hellwig static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, 645abc97aaSJens Axboe struct pipe_buffer *buf) 655abc97aaSJens Axboe { 665100da38SMatthew Wilcox (Oracle) struct folio *folio = page_folio(buf->page); 679e94cd4fSJens Axboe struct address_space *mapping; 685abc97aaSJens Axboe 69b9ccad2eSMatthew Wilcox (Oracle) folio_lock(folio); 709e0267c2SJens Axboe 71b9ccad2eSMatthew Wilcox (Oracle) mapping = folio_mapping(folio); 729e94cd4fSJens Axboe if (mapping) { 73b9ccad2eSMatthew Wilcox (Oracle) WARN_ON(!folio_test_uptodate(folio)); 745abc97aaSJens Axboe 75ad8d6f0aSJens Axboe /* 769e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 77b9ccad2eSMatthew Wilcox (Oracle) * writeback completing on this folio, since we'll remove it 789e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 79b9ccad2eSMatthew Wilcox (Oracle) * folio, allowing the disk blocks to be reused by someone else 809e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 819e94cd4fSJens Axboe * ensues. 82ad8d6f0aSJens Axboe */ 83b9ccad2eSMatthew Wilcox (Oracle) folio_wait_writeback(folio); 84ad8d6f0aSJens Axboe 85b9ccad2eSMatthew Wilcox (Oracle) if (folio_has_private(folio) && 86b9ccad2eSMatthew Wilcox (Oracle) !filemap_release_folio(folio, GFP_KERNEL)) 87ca39d651SJens Axboe goto out_unlock; 884f6f0bd2SJens Axboe 899e94cd4fSJens Axboe /* 909e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 919e94cd4fSJens Axboe * and return good. 929e94cd4fSJens Axboe */ 935100da38SMatthew Wilcox (Oracle) if (remove_mapping(mapping, folio)) { 941432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 95c928f642SChristoph Hellwig return true; 965abc97aaSJens Axboe } 979e94cd4fSJens Axboe } 989e94cd4fSJens Axboe 999e94cd4fSJens Axboe /* 100b9ccad2eSMatthew Wilcox (Oracle) * Raced with truncate or failed to remove folio from current 1019e94cd4fSJens Axboe * address space, unlock and return failure. 1029e94cd4fSJens Axboe */ 103ca39d651SJens Axboe out_unlock: 104b9ccad2eSMatthew Wilcox (Oracle) folio_unlock(folio); 105c928f642SChristoph Hellwig return false; 1069e94cd4fSJens Axboe } 1075abc97aaSJens Axboe 10876ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 1095274f052SJens Axboe struct pipe_buffer *buf) 1105274f052SJens Axboe { 11109cbfeafSKirill A. Shutemov put_page(buf->page); 1121432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 1135274f052SJens Axboe } 1145274f052SJens Axboe 1150845718dSJens Axboe /* 1160845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 1170845718dSJens Axboe * is a page cache page, IO may be in flight. 1180845718dSJens Axboe */ 119cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 1205274f052SJens Axboe struct pipe_buffer *buf) 1215274f052SJens Axboe { 1225274f052SJens Axboe struct page *page = buf->page; 12349d0b21bSJens Axboe int err; 1245274f052SJens Axboe 1255274f052SJens Axboe if (!PageUptodate(page)) { 12649d0b21bSJens Axboe lock_page(page); 1275274f052SJens Axboe 12849d0b21bSJens Axboe /* 12949d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 13073d62d83SIngo Molnar * splice, if this is the first page. 13149d0b21bSJens Axboe */ 1325274f052SJens Axboe if (!page->mapping) { 13349d0b21bSJens Axboe err = -ENODATA; 13449d0b21bSJens Axboe goto error; 1355274f052SJens Axboe } 1365274f052SJens Axboe 13749d0b21bSJens Axboe /* 13873d62d83SIngo Molnar * Uh oh, read-error from disk. 13949d0b21bSJens Axboe */ 14049d0b21bSJens Axboe if (!PageUptodate(page)) { 14149d0b21bSJens Axboe err = -EIO; 14249d0b21bSJens Axboe goto error; 14349d0b21bSJens Axboe } 14449d0b21bSJens Axboe 14549d0b21bSJens Axboe /* 146f84d7519SJens Axboe * Page is ok afterall, we are done. 14749d0b21bSJens Axboe */ 14849d0b21bSJens Axboe unlock_page(page); 14949d0b21bSJens Axboe } 15049d0b21bSJens Axboe 151f84d7519SJens Axboe return 0; 15249d0b21bSJens Axboe error: 15349d0b21bSJens Axboe unlock_page(page); 154f84d7519SJens Axboe return err; 15570524490SJens Axboe } 15670524490SJens Axboe 157708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 158cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1595274f052SJens Axboe .release = page_cache_pipe_buf_release, 160c928f642SChristoph Hellwig .try_steal = page_cache_pipe_buf_try_steal, 161f84d7519SJens Axboe .get = generic_pipe_buf_get, 1625274f052SJens Axboe }; 1635274f052SJens Axboe 164c928f642SChristoph Hellwig static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, 165912d35f8SJens Axboe struct pipe_buffer *buf) 166912d35f8SJens Axboe { 1677afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 168c928f642SChristoph Hellwig return false; 1697afa6fd0SJens Axboe 1701432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 171c928f642SChristoph Hellwig return generic_pipe_buf_try_steal(pipe, buf); 172912d35f8SJens Axboe } 173912d35f8SJens Axboe 174d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 175912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 176c928f642SChristoph Hellwig .try_steal = user_page_pipe_buf_try_steal, 177f84d7519SJens Axboe .get = generic_pipe_buf_get, 178912d35f8SJens Axboe }; 179912d35f8SJens Axboe 180825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 181825cdcb1SNamhyung Kim { 182825cdcb1SNamhyung Kim smp_mb(); 1830ddad21dSLinus Torvalds if (waitqueue_active(&pipe->rd_wait)) 1840ddad21dSLinus Torvalds wake_up_interruptible(&pipe->rd_wait); 185825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 186825cdcb1SNamhyung Kim } 187825cdcb1SNamhyung Kim 188932cc6d4SJens Axboe /** 189932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 190932cc6d4SJens Axboe * @pipe: pipe to fill 191932cc6d4SJens Axboe * @spd: data to fill 192932cc6d4SJens Axboe * 193932cc6d4SJens Axboe * Description: 19479685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 195932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 196932cc6d4SJens Axboe * function will link that data to the pipe. 197932cc6d4SJens Axboe * 19883f9135bSJens Axboe */ 199d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 200912d35f8SJens Axboe struct splice_pipe_desc *spd) 2015274f052SJens Axboe { 20200de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 2038cefc107SDavid Howells unsigned int tail = pipe->tail; 2048cefc107SDavid Howells unsigned int head = pipe->head; 2058cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 2068924feffSAl Viro int ret = 0, page_nr = 0; 2075274f052SJens Axboe 208d6785d91SRabin Vincent if (!spd_pages) 209d6785d91SRabin Vincent return 0; 210d6785d91SRabin Vincent 2118924feffSAl Viro if (unlikely(!pipe->readers)) { 2125274f052SJens Axboe send_sig(SIGPIPE, current, 0); 2135274f052SJens Axboe ret = -EPIPE; 2148924feffSAl Viro goto out; 2155274f052SJens Axboe } 2165274f052SJens Axboe 2176718b6f8SDavid Howells while (!pipe_full(head, tail, pipe->max_usage)) { 2188cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[head & mask]; 2195274f052SJens Axboe 220912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 221912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 222912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 223497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 224912d35f8SJens Axboe buf->ops = spd->ops; 2255a81e6a1SMiklos Szeredi buf->flags = 0; 2267afa6fd0SJens Axboe 2278cefc107SDavid Howells head++; 2288cefc107SDavid Howells pipe->head = head; 229912d35f8SJens Axboe page_nr++; 230912d35f8SJens Axboe ret += buf->len; 231912d35f8SJens Axboe 232912d35f8SJens Axboe if (!--spd->nr_pages) 2335274f052SJens Axboe break; 2345274f052SJens Axboe } 2355274f052SJens Axboe 23629e35094SLinus Torvalds if (!ret) 23729e35094SLinus Torvalds ret = -EAGAIN; 23829e35094SLinus Torvalds 2398924feffSAl Viro out: 24000de00bdSJens Axboe while (page_nr < spd_pages) 241bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2425274f052SJens Axboe 2435274f052SJens Axboe return ret; 2445274f052SJens Axboe } 2452b514574SHannes Frederic Sowa EXPORT_SYMBOL_GPL(splice_to_pipe); 2465274f052SJens Axboe 24779fddc4eSAl Viro ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 24879fddc4eSAl Viro { 2498cefc107SDavid Howells unsigned int head = pipe->head; 2508cefc107SDavid Howells unsigned int tail = pipe->tail; 2518cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 25279fddc4eSAl Viro int ret; 25379fddc4eSAl Viro 25479fddc4eSAl Viro if (unlikely(!pipe->readers)) { 25579fddc4eSAl Viro send_sig(SIGPIPE, current, 0); 25679fddc4eSAl Viro ret = -EPIPE; 2576718b6f8SDavid Howells } else if (pipe_full(head, tail, pipe->max_usage)) { 25879fddc4eSAl Viro ret = -EAGAIN; 25979fddc4eSAl Viro } else { 2608cefc107SDavid Howells pipe->bufs[head & mask] = *buf; 2618cefc107SDavid Howells pipe->head = head + 1; 26279fddc4eSAl Viro return buf->len; 26379fddc4eSAl Viro } 264a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 26579fddc4eSAl Viro return ret; 26679fddc4eSAl Viro } 26779fddc4eSAl Viro EXPORT_SYMBOL(add_to_pipe); 26879fddc4eSAl Viro 26935f3d14dSJens Axboe /* 27035f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 27135f3d14dSJens Axboe * descriptions. 27235f3d14dSJens Axboe */ 273047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 27435f3d14dSJens Axboe { 2756718b6f8SDavid Howells unsigned int max_usage = READ_ONCE(pipe->max_usage); 276047fe360SEric Dumazet 2778cefc107SDavid Howells spd->nr_pages_max = max_usage; 2788cefc107SDavid Howells if (max_usage <= PIPE_DEF_BUFFERS) 27935f3d14dSJens Axboe return 0; 28035f3d14dSJens Axboe 2818cefc107SDavid Howells spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); 2828cefc107SDavid Howells spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), 2836da2ec56SKees Cook GFP_KERNEL); 28435f3d14dSJens Axboe 28535f3d14dSJens Axboe if (spd->pages && spd->partial) 28635f3d14dSJens Axboe return 0; 28735f3d14dSJens Axboe 28835f3d14dSJens Axboe kfree(spd->pages); 28935f3d14dSJens Axboe kfree(spd->partial); 29035f3d14dSJens Axboe return -ENOMEM; 29135f3d14dSJens Axboe } 29235f3d14dSJens Axboe 293047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 29435f3d14dSJens Axboe { 295047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 29635f3d14dSJens Axboe return; 29735f3d14dSJens Axboe 29835f3d14dSJens Axboe kfree(spd->pages); 29935f3d14dSJens Axboe kfree(spd->partial); 30035f3d14dSJens Axboe } 30135f3d14dSJens Axboe 30233b3b041SDavid Howells /* 30369df79a4SDavid Howells * Copy data from a file into pages and then splice those into the output pipe. 30433b3b041SDavid Howells */ 30569df79a4SDavid Howells ssize_t copy_splice_read(struct file *in, loff_t *ppos, 30633b3b041SDavid Howells struct pipe_inode_info *pipe, 30733b3b041SDavid Howells size_t len, unsigned int flags) 30833b3b041SDavid Howells { 30933b3b041SDavid Howells struct iov_iter to; 31033b3b041SDavid Howells struct bio_vec *bv; 31133b3b041SDavid Howells struct kiocb kiocb; 31233b3b041SDavid Howells struct page **pages; 31333b3b041SDavid Howells ssize_t ret; 314e69f37bcSDavid Howells size_t used, npages, chunk, remain, keep = 0; 31533b3b041SDavid Howells int i; 31633b3b041SDavid Howells 31733b3b041SDavid Howells /* Work out how much data we can actually add into the pipe */ 31833b3b041SDavid Howells used = pipe_occupancy(pipe->head, pipe->tail); 31933b3b041SDavid Howells npages = max_t(ssize_t, pipe->max_usage - used, 0); 32033b3b041SDavid Howells len = min_t(size_t, len, npages * PAGE_SIZE); 32133b3b041SDavid Howells npages = DIV_ROUND_UP(len, PAGE_SIZE); 32233b3b041SDavid Howells 32333b3b041SDavid Howells bv = kzalloc(array_size(npages, sizeof(bv[0])) + 32433b3b041SDavid Howells array_size(npages, sizeof(struct page *)), GFP_KERNEL); 32533b3b041SDavid Howells if (!bv) 32633b3b041SDavid Howells return -ENOMEM; 32733b3b041SDavid Howells 328e69f37bcSDavid Howells pages = (struct page **)(bv + npages); 32933b3b041SDavid Howells npages = alloc_pages_bulk_array(GFP_USER, npages, pages); 33033b3b041SDavid Howells if (!npages) { 33133b3b041SDavid Howells kfree(bv); 33233b3b041SDavid Howells return -ENOMEM; 33333b3b041SDavid Howells } 33433b3b041SDavid Howells 33533b3b041SDavid Howells remain = len = min_t(size_t, len, npages * PAGE_SIZE); 33633b3b041SDavid Howells 33733b3b041SDavid Howells for (i = 0; i < npages; i++) { 33833b3b041SDavid Howells chunk = min_t(size_t, PAGE_SIZE, remain); 33933b3b041SDavid Howells bv[i].bv_page = pages[i]; 34033b3b041SDavid Howells bv[i].bv_offset = 0; 34133b3b041SDavid Howells bv[i].bv_len = chunk; 34233b3b041SDavid Howells remain -= chunk; 34333b3b041SDavid Howells } 34433b3b041SDavid Howells 34533b3b041SDavid Howells /* Do the I/O */ 34633b3b041SDavid Howells iov_iter_bvec(&to, ITER_DEST, bv, npages, len); 34733b3b041SDavid Howells init_sync_kiocb(&kiocb, in); 34833b3b041SDavid Howells kiocb.ki_pos = *ppos; 34933b3b041SDavid Howells ret = call_read_iter(in, &kiocb, &to); 35033b3b041SDavid Howells 35133b3b041SDavid Howells if (ret > 0) { 352e69f37bcSDavid Howells keep = DIV_ROUND_UP(ret, PAGE_SIZE); 35333b3b041SDavid Howells *ppos = kiocb.ki_pos; 35433b3b041SDavid Howells file_accessed(in); 35533b3b041SDavid Howells } else if (ret < 0) { 35633b3b041SDavid Howells /* 35733b3b041SDavid Howells * callers of ->splice_read() expect -EAGAIN on 35833b3b041SDavid Howells * "can't put anything in there", rather than -EFAULT. 35933b3b041SDavid Howells */ 36033b3b041SDavid Howells if (ret == -EFAULT) 36133b3b041SDavid Howells ret = -EAGAIN; 36233b3b041SDavid Howells } 36333b3b041SDavid Howells 36433b3b041SDavid Howells /* Free any pages that didn't get touched at all. */ 365e69f37bcSDavid Howells if (keep < npages) 366e69f37bcSDavid Howells release_pages(pages + keep, npages - keep); 36733b3b041SDavid Howells 36833b3b041SDavid Howells /* Push the remaining pages into the pipe. */ 369e69f37bcSDavid Howells remain = ret; 370e69f37bcSDavid Howells for (i = 0; i < keep; i++) { 37133b3b041SDavid Howells struct pipe_buffer *buf = pipe_head_buf(pipe); 37233b3b041SDavid Howells 37333b3b041SDavid Howells chunk = min_t(size_t, remain, PAGE_SIZE); 37433b3b041SDavid Howells *buf = (struct pipe_buffer) { 37533b3b041SDavid Howells .ops = &default_pipe_buf_ops, 37633b3b041SDavid Howells .page = bv[i].bv_page, 37733b3b041SDavid Howells .offset = 0, 37833b3b041SDavid Howells .len = chunk, 37933b3b041SDavid Howells }; 38033b3b041SDavid Howells pipe->head++; 38133b3b041SDavid Howells remain -= chunk; 38233b3b041SDavid Howells } 38333b3b041SDavid Howells 38433b3b041SDavid Howells kfree(bv); 38533b3b041SDavid Howells return ret; 38633b3b041SDavid Howells } 38769df79a4SDavid Howells EXPORT_SYMBOL(copy_splice_read); 38833b3b041SDavid Howells 38983f9135bSJens Axboe /** 39083f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 39183f9135bSJens Axboe * @in: file to splice from 392932cc6d4SJens Axboe * @ppos: position in @in 39383f9135bSJens Axboe * @pipe: pipe to splice to 39483f9135bSJens Axboe * @len: number of bytes to splice 39583f9135bSJens Axboe * @flags: splice modifier flags 39683f9135bSJens Axboe * 397932cc6d4SJens Axboe * Description: 398932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 39982c156f8SAl Viro * used as long as it has more or less sane ->read_iter(). 400932cc6d4SJens Axboe * 40183f9135bSJens Axboe */ 402cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 403cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 404cbb7e577SJens Axboe unsigned int flags) 4055274f052SJens Axboe { 40682c156f8SAl Viro struct iov_iter to; 40782c156f8SAl Viro struct kiocb kiocb; 4088cefc107SDavid Howells int ret; 409be64f884SBoaz Harrosh 410de4eda9dSAl Viro iov_iter_pipe(&to, ITER_DEST, pipe, len); 41182c156f8SAl Viro init_sync_kiocb(&kiocb, in); 41282c156f8SAl Viro kiocb.ki_pos = *ppos; 413bb7462b6SMiklos Szeredi ret = call_read_iter(in, &kiocb, &to); 414723590edSMiklos Szeredi if (ret > 0) { 41582c156f8SAl Viro *ppos = kiocb.ki_pos; 416723590edSMiklos Szeredi file_accessed(in); 41782c156f8SAl Viro } else if (ret < 0) { 4180d964934SAl Viro /* free what was emitted */ 4190d964934SAl Viro pipe_discard_from(pipe, to.start_head); 42082c156f8SAl Viro /* 42182c156f8SAl Viro * callers of ->splice_read() expect -EAGAIN on 42282c156f8SAl Viro * "can't put anything in there", rather than -EFAULT. 42382c156f8SAl Viro */ 42482c156f8SAl Viro if (ret == -EFAULT) 42582c156f8SAl Viro ret = -EAGAIN; 426723590edSMiklos Szeredi } 4275274f052SJens Axboe 4285274f052SJens Axboe return ret; 4295274f052SJens Axboe } 430059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 431059a8f37SJens Axboe 432241699cdSAl Viro const struct pipe_buf_operations default_pipe_buf_ops = { 4336818173bSMiklos Szeredi .release = generic_pipe_buf_release, 434c928f642SChristoph Hellwig .try_steal = generic_pipe_buf_try_steal, 4356818173bSMiklos Szeredi .get = generic_pipe_buf_get, 4366818173bSMiklos Szeredi }; 4376818173bSMiklos Szeredi 43828a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 43928a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 44028a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 44128a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 44228a625cbSMiklos Szeredi }; 44328a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 44428a625cbSMiklos Szeredi 4455274f052SJens Axboe /* 4464f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 447016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4485274f052SJens Axboe */ 44976ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 4505274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4515274f052SJens Axboe { 4526a14b90bSJens Axboe struct file *file = sd->u.file; 4535274f052SJens Axboe loff_t pos = sd->pos; 454a8adbe37SMichał Mirosław int more; 4555274f052SJens Axboe 45672c2d531SAl Viro if (!likely(file->f_op->sendpage)) 457a8adbe37SMichał Mirosław return -EINVAL; 458a8adbe37SMichał Mirosław 45935f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 460ae62ca7bSEric Dumazet 4618cefc107SDavid Howells if (sd->len < sd->total_len && 4628cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail) > 1) 46335f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 464ae62ca7bSEric Dumazet 465a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 466f84d7519SJens Axboe sd->len, &pos, more); 4675274f052SJens Axboe } 4685274f052SJens Axboe 469b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 470b3c2d2ddSMiklos Szeredi { 471b3c2d2ddSMiklos Szeredi smp_mb(); 4720ddad21dSLinus Torvalds if (waitqueue_active(&pipe->wr_wait)) 4730ddad21dSLinus Torvalds wake_up_interruptible(&pipe->wr_wait); 474b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 475b3c2d2ddSMiklos Szeredi } 476b3c2d2ddSMiklos Szeredi 477b3c2d2ddSMiklos Szeredi /** 478b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 479b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 480b3c2d2ddSMiklos Szeredi * @sd: information to @actor 481b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 482b3c2d2ddSMiklos Szeredi * 483b3c2d2ddSMiklos Szeredi * Description: 484b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 485b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 486b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 487b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 488b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 489b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 490b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 491b3c2d2ddSMiklos Szeredi * 492b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 493b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 494b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 495b3c2d2ddSMiklos Szeredi * destination. 496b3c2d2ddSMiklos Szeredi */ 49796f9bc8fSAl Viro static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 498b3c2d2ddSMiklos Szeredi splice_actor *actor) 499b3c2d2ddSMiklos Szeredi { 5008cefc107SDavid Howells unsigned int head = pipe->head; 5018cefc107SDavid Howells unsigned int tail = pipe->tail; 5028cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 503b3c2d2ddSMiklos Szeredi int ret; 504b3c2d2ddSMiklos Szeredi 505ec057595SLinus Torvalds while (!pipe_empty(head, tail)) { 5068cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 507b3c2d2ddSMiklos Szeredi 508b3c2d2ddSMiklos Szeredi sd->len = buf->len; 509b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 510b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 511b3c2d2ddSMiklos Szeredi 512fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 513a8adbe37SMichał Mirosław if (unlikely(ret)) { 514b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 515b3c2d2ddSMiklos Szeredi ret = 0; 516b3c2d2ddSMiklos Szeredi return ret; 517b3c2d2ddSMiklos Szeredi } 518a8adbe37SMichał Mirosław 519a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 520a8adbe37SMichał Mirosław if (ret <= 0) 521a8adbe37SMichał Mirosław return ret; 522a8adbe37SMichał Mirosław 523b3c2d2ddSMiklos Szeredi buf->offset += ret; 524b3c2d2ddSMiklos Szeredi buf->len -= ret; 525b3c2d2ddSMiklos Szeredi 526b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 527b3c2d2ddSMiklos Szeredi sd->len -= ret; 528b3c2d2ddSMiklos Szeredi sd->pos += ret; 529b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 530b3c2d2ddSMiklos Szeredi 531b3c2d2ddSMiklos Szeredi if (!buf->len) { 532a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 5338cefc107SDavid Howells tail++; 5348cefc107SDavid Howells pipe->tail = tail; 5356447a3cfSAl Viro if (pipe->files) 536b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 537b3c2d2ddSMiklos Szeredi } 538b3c2d2ddSMiklos Szeredi 539b3c2d2ddSMiklos Szeredi if (!sd->total_len) 540b3c2d2ddSMiklos Szeredi return 0; 541b3c2d2ddSMiklos Szeredi } 542b3c2d2ddSMiklos Szeredi 543b3c2d2ddSMiklos Szeredi return 1; 544b3c2d2ddSMiklos Szeredi } 545b3c2d2ddSMiklos Szeredi 546d1a819a2SLinus Torvalds /* We know we have a pipe buffer, but maybe it's empty? */ 547d1a819a2SLinus Torvalds static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) 548d1a819a2SLinus Torvalds { 549d1a819a2SLinus Torvalds unsigned int tail = pipe->tail; 550d1a819a2SLinus Torvalds unsigned int mask = pipe->ring_size - 1; 551d1a819a2SLinus Torvalds struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 552d1a819a2SLinus Torvalds 553d1a819a2SLinus Torvalds if (unlikely(!buf->len)) { 554d1a819a2SLinus Torvalds pipe_buf_release(pipe, buf); 555d1a819a2SLinus Torvalds pipe->tail = tail+1; 556d1a819a2SLinus Torvalds return true; 557d1a819a2SLinus Torvalds } 558d1a819a2SLinus Torvalds 559d1a819a2SLinus Torvalds return false; 560d1a819a2SLinus Torvalds } 561d1a819a2SLinus Torvalds 562b3c2d2ddSMiklos Szeredi /** 563b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 564b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 565b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 566b3c2d2ddSMiklos Szeredi * 567b3c2d2ddSMiklos Szeredi * Description: 568b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 569b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 570b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 571b3c2d2ddSMiklos Szeredi */ 57296f9bc8fSAl Viro static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 573b3c2d2ddSMiklos Szeredi { 574c725bfceSJan Kara /* 575c725bfceSJan Kara * Check for signal early to make process killable when there are 576c725bfceSJan Kara * always buffers available 577c725bfceSJan Kara */ 578c725bfceSJan Kara if (signal_pending(current)) 579c725bfceSJan Kara return -ERESTARTSYS; 580c725bfceSJan Kara 581d1a819a2SLinus Torvalds repeat: 5828cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 583b3c2d2ddSMiklos Szeredi if (!pipe->writers) 584b3c2d2ddSMiklos Szeredi return 0; 585b3c2d2ddSMiklos Szeredi 586a28c8b9dSLinus Torvalds if (sd->num_spliced) 587b3c2d2ddSMiklos Szeredi return 0; 588b3c2d2ddSMiklos Szeredi 589b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 590b3c2d2ddSMiklos Szeredi return -EAGAIN; 591b3c2d2ddSMiklos Szeredi 592b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 593b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 594b3c2d2ddSMiklos Szeredi 595b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 596b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 597b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 598b3c2d2ddSMiklos Szeredi } 599b3c2d2ddSMiklos Szeredi 600472e5b05SLinus Torvalds pipe_wait_readable(pipe); 601b3c2d2ddSMiklos Szeredi } 602b3c2d2ddSMiklos Szeredi 603d1a819a2SLinus Torvalds if (eat_empty_buffer(pipe)) 604d1a819a2SLinus Torvalds goto repeat; 605d1a819a2SLinus Torvalds 606b3c2d2ddSMiklos Szeredi return 1; 607b3c2d2ddSMiklos Szeredi } 608b3c2d2ddSMiklos Szeredi 609b3c2d2ddSMiklos Szeredi /** 610b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 611b80901bbSRandy Dunlap * @sd: information about the splice operation 612b3c2d2ddSMiklos Szeredi * 613b3c2d2ddSMiklos Szeredi * Description: 614b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 615b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 616b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 617b3c2d2ddSMiklos Szeredi */ 61896f9bc8fSAl Viro static void splice_from_pipe_begin(struct splice_desc *sd) 619b3c2d2ddSMiklos Szeredi { 620b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 621b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 622b3c2d2ddSMiklos Szeredi } 623b3c2d2ddSMiklos Szeredi 624b3c2d2ddSMiklos Szeredi /** 625b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 626b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 627b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 628b3c2d2ddSMiklos Szeredi * 629b3c2d2ddSMiklos Szeredi * Description: 630b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 631b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 632b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 633b3c2d2ddSMiklos Szeredi */ 63496f9bc8fSAl Viro static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 635b3c2d2ddSMiklos Szeredi { 636b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 637b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 638b3c2d2ddSMiklos Szeredi } 639b3c2d2ddSMiklos Szeredi 640932cc6d4SJens Axboe /** 641932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 642932cc6d4SJens Axboe * @pipe: pipe to splice from 643932cc6d4SJens Axboe * @sd: information to @actor 644932cc6d4SJens Axboe * @actor: handler that splices the data 645932cc6d4SJens Axboe * 646932cc6d4SJens Axboe * Description: 647932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 648932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 649932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 650932cc6d4SJens Axboe * pipe_to_user. 651932cc6d4SJens Axboe * 65283f9135bSJens Axboe */ 653c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 654c66ab6faSJens Axboe splice_actor *actor) 6555274f052SJens Axboe { 656b3c2d2ddSMiklos Szeredi int ret; 6575274f052SJens Axboe 658b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 659b3c2d2ddSMiklos Szeredi do { 660c2489e07SJan Kara cond_resched(); 661b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 662b3c2d2ddSMiklos Szeredi if (ret > 0) 663b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 664b3c2d2ddSMiklos Szeredi } while (ret > 0); 665b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 6665274f052SJens Axboe 667b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 6685274f052SJens Axboe } 66940bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6705274f052SJens Axboe 671932cc6d4SJens Axboe /** 672932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 673932cc6d4SJens Axboe * @pipe: pipe to splice from 674932cc6d4SJens Axboe * @out: file to splice to 675932cc6d4SJens Axboe * @ppos: position in @out 676932cc6d4SJens Axboe * @len: how many bytes to splice 677932cc6d4SJens Axboe * @flags: splice modifier flags 678932cc6d4SJens Axboe * @actor: handler that splices the data 679932cc6d4SJens Axboe * 680932cc6d4SJens Axboe * Description: 6812933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 682932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 683932cc6d4SJens Axboe * 684932cc6d4SJens Axboe */ 6856da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 6866da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 6876da61809SMark Fasheh splice_actor *actor) 6886da61809SMark Fasheh { 6896da61809SMark Fasheh ssize_t ret; 690c66ab6faSJens Axboe struct splice_desc sd = { 691c66ab6faSJens Axboe .total_len = len, 692c66ab6faSJens Axboe .flags = flags, 693c66ab6faSJens Axboe .pos = *ppos, 6946a14b90bSJens Axboe .u.file = out, 695c66ab6faSJens Axboe }; 6966da61809SMark Fasheh 69761e0d47cSMiklos Szeredi pipe_lock(pipe); 698c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 69961e0d47cSMiklos Szeredi pipe_unlock(pipe); 7006da61809SMark Fasheh 7016da61809SMark Fasheh return ret; 7026da61809SMark Fasheh } 7036da61809SMark Fasheh 7046da61809SMark Fasheh /** 7058d020765SAl Viro * iter_file_splice_write - splice data from a pipe to a file 7068d020765SAl Viro * @pipe: pipe info 7078d020765SAl Viro * @out: file to write to 7088d020765SAl Viro * @ppos: position in @out 7098d020765SAl Viro * @len: number of bytes to splice 7108d020765SAl Viro * @flags: splice modifier flags 7118d020765SAl Viro * 7128d020765SAl Viro * Description: 7138d020765SAl Viro * Will either move or copy pages (determined by @flags options) from 7148d020765SAl Viro * the given pipe inode to the given file. 7158d020765SAl Viro * This one is ->write_iter-based. 7168d020765SAl Viro * 7178d020765SAl Viro */ 7188d020765SAl Viro ssize_t 7198d020765SAl Viro iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 7208d020765SAl Viro loff_t *ppos, size_t len, unsigned int flags) 7218d020765SAl Viro { 7228d020765SAl Viro struct splice_desc sd = { 7238d020765SAl Viro .total_len = len, 7248d020765SAl Viro .flags = flags, 7258d020765SAl Viro .pos = *ppos, 7268d020765SAl Viro .u.file = out, 7278d020765SAl Viro }; 7286718b6f8SDavid Howells int nbufs = pipe->max_usage; 7298d020765SAl Viro struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), 7308d020765SAl Viro GFP_KERNEL); 7318d020765SAl Viro ssize_t ret; 7328d020765SAl Viro 7338d020765SAl Viro if (unlikely(!array)) 7348d020765SAl Viro return -ENOMEM; 7358d020765SAl Viro 7368d020765SAl Viro pipe_lock(pipe); 7378d020765SAl Viro 7388d020765SAl Viro splice_from_pipe_begin(&sd); 7398d020765SAl Viro while (sd.total_len) { 7408d020765SAl Viro struct iov_iter from; 741ec057595SLinus Torvalds unsigned int head, tail, mask; 7428d020765SAl Viro size_t left; 7438cefc107SDavid Howells int n; 7448d020765SAl Viro 7458d020765SAl Viro ret = splice_from_pipe_next(pipe, &sd); 7468d020765SAl Viro if (ret <= 0) 7478d020765SAl Viro break; 7488d020765SAl Viro 7496718b6f8SDavid Howells if (unlikely(nbufs < pipe->max_usage)) { 7508d020765SAl Viro kfree(array); 7516718b6f8SDavid Howells nbufs = pipe->max_usage; 7528d020765SAl Viro array = kcalloc(nbufs, sizeof(struct bio_vec), 7538d020765SAl Viro GFP_KERNEL); 7548d020765SAl Viro if (!array) { 7558d020765SAl Viro ret = -ENOMEM; 7568d020765SAl Viro break; 7578d020765SAl Viro } 7588d020765SAl Viro } 7598d020765SAl Viro 760ec057595SLinus Torvalds head = pipe->head; 761ec057595SLinus Torvalds tail = pipe->tail; 762ec057595SLinus Torvalds mask = pipe->ring_size - 1; 763ec057595SLinus Torvalds 7648d020765SAl Viro /* build the vector */ 7658d020765SAl Viro left = sd.total_len; 7660f1d344fSPavel Begunkov for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { 7678cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7688d020765SAl Viro size_t this_len = buf->len; 7698d020765SAl Viro 7700f1d344fSPavel Begunkov /* zero-length bvecs are not supported, skip them */ 7710f1d344fSPavel Begunkov if (!this_len) 7720f1d344fSPavel Begunkov continue; 7730f1d344fSPavel Begunkov this_len = min(this_len, left); 7748d020765SAl Viro 775fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 7768d020765SAl Viro if (unlikely(ret)) { 7778d020765SAl Viro if (ret == -ENODATA) 7788d020765SAl Viro ret = 0; 7798d020765SAl Viro goto done; 7808d020765SAl Viro } 7818d020765SAl Viro 782664e4078SChristoph Hellwig bvec_set_page(&array[n], buf->page, this_len, 783664e4078SChristoph Hellwig buf->offset); 7848d020765SAl Viro left -= this_len; 7850f1d344fSPavel Begunkov n++; 7868d020765SAl Viro } 7878d020765SAl Viro 788de4eda9dSAl Viro iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); 789abbb6589SChristoph Hellwig ret = vfs_iter_write(out, &from, &sd.pos, 0); 7908d020765SAl Viro if (ret <= 0) 7918d020765SAl Viro break; 7928d020765SAl Viro 7938d020765SAl Viro sd.num_spliced += ret; 7948d020765SAl Viro sd.total_len -= ret; 795dbe4e192SChristoph Hellwig *ppos = sd.pos; 7968d020765SAl Viro 7978d020765SAl Viro /* dismiss the fully eaten buffers, adjust the partial one */ 7988cefc107SDavid Howells tail = pipe->tail; 7998d020765SAl Viro while (ret) { 8008cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 8018d020765SAl Viro if (ret >= buf->len) { 8028d020765SAl Viro ret -= buf->len; 8038d020765SAl Viro buf->len = 0; 804a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 8058cefc107SDavid Howells tail++; 8068cefc107SDavid Howells pipe->tail = tail; 8078d020765SAl Viro if (pipe->files) 8088d020765SAl Viro sd.need_wakeup = true; 8098d020765SAl Viro } else { 8108d020765SAl Viro buf->offset += ret; 8118d020765SAl Viro buf->len -= ret; 8128d020765SAl Viro ret = 0; 8138d020765SAl Viro } 8148d020765SAl Viro } 8158d020765SAl Viro } 8168d020765SAl Viro done: 8178d020765SAl Viro kfree(array); 8188d020765SAl Viro splice_from_pipe_end(pipe, &sd); 8198d020765SAl Viro 8208d020765SAl Viro pipe_unlock(pipe); 8218d020765SAl Viro 8228d020765SAl Viro if (sd.num_spliced) 8238d020765SAl Viro ret = sd.num_spliced; 8248d020765SAl Viro 8258d020765SAl Viro return ret; 8268d020765SAl Viro } 8278d020765SAl Viro 8288d020765SAl Viro EXPORT_SYMBOL(iter_file_splice_write); 8298d020765SAl Viro 83083f9135bSJens Axboe /** 83183f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 832932cc6d4SJens Axboe * @pipe: pipe to splice from 83383f9135bSJens Axboe * @out: socket to write to 834932cc6d4SJens Axboe * @ppos: position in @out 83583f9135bSJens Axboe * @len: number of bytes to splice 83683f9135bSJens Axboe * @flags: splice modifier flags 83783f9135bSJens Axboe * 838932cc6d4SJens Axboe * Description: 83983f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 84083f9135bSJens Axboe * is involved. 84183f9135bSJens Axboe * 84283f9135bSJens Axboe */ 8433a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 844cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8455274f052SJens Axboe { 84600522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8475274f052SJens Axboe } 8485274f052SJens Axboe 849059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 850a0f06780SJeff Garzik 85136e2c742SChristoph Hellwig static int warn_unsupported(struct file *file, const char *op) 85236e2c742SChristoph Hellwig { 85336e2c742SChristoph Hellwig pr_debug_ratelimited( 85436e2c742SChristoph Hellwig "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", 85536e2c742SChristoph Hellwig op, file, current->pid, current->comm); 85636e2c742SChristoph Hellwig return -EINVAL; 85736e2c742SChristoph Hellwig } 85836e2c742SChristoph Hellwig 85983f9135bSJens Axboe /* 86083f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 86183f9135bSJens Axboe */ 8623a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 863cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8645274f052SJens Axboe { 86536e2c742SChristoph Hellwig if (unlikely(!out->f_op->splice_write)) 86636e2c742SChristoph Hellwig return warn_unsupported(out, "write"); 86700c285d0SChristoph Hellwig return out->f_op->splice_write(pipe, out, ppos, len, flags); 8685274f052SJens Axboe } 8695274f052SJens Axboe 8706a3f30b8SDavid Howells /** 8716a3f30b8SDavid Howells * vfs_splice_read - Read data from a file and splice it into a pipe 8726a3f30b8SDavid Howells * @in: File to splice from 8736a3f30b8SDavid Howells * @ppos: Input file offset 8746a3f30b8SDavid Howells * @pipe: Pipe to splice to 8756a3f30b8SDavid Howells * @len: Number of bytes to splice 8766a3f30b8SDavid Howells * @flags: Splice modifier flags (SPLICE_F_*) 8776a3f30b8SDavid Howells * 8786a3f30b8SDavid Howells * Splice the requested amount of data from the input file to the pipe. This 8796a3f30b8SDavid Howells * is synchronous as the caller must hold the pipe lock across the entire 8806a3f30b8SDavid Howells * operation. 8816a3f30b8SDavid Howells * 8826a3f30b8SDavid Howells * If successful, it returns the amount of data spliced, 0 if it hit the EOF or 8836a3f30b8SDavid Howells * a hole and a negative error code otherwise. 88483f9135bSJens Axboe */ 8856a3f30b8SDavid Howells long vfs_splice_read(struct file *in, loff_t *ppos, 886cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 887cbb7e577SJens Axboe unsigned int flags) 8885274f052SJens Axboe { 889313d64a3SAl Viro unsigned int p_space; 8905274f052SJens Axboe int ret; 8915274f052SJens Axboe 89249570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8935274f052SJens Axboe return -EBADF; 894123856f0SDavid Howells if (!len) 895123856f0SDavid Howells return 0; 8965274f052SJens Axboe 897313d64a3SAl Viro /* Don't try to read more the pipe has space for. */ 898313d64a3SAl Viro p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); 899313d64a3SAl Viro len = min_t(size_t, len, p_space << PAGE_SHIFT); 900313d64a3SAl Viro 901cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 9025274f052SJens Axboe if (unlikely(ret < 0)) 9035274f052SJens Axboe return ret; 9045274f052SJens Axboe 90503cc0789SAl Viro if (unlikely(len > MAX_RW_COUNT)) 90603cc0789SAl Viro len = MAX_RW_COUNT; 90703cc0789SAl Viro 90836e2c742SChristoph Hellwig if (unlikely(!in->f_op->splice_read)) 90936e2c742SChristoph Hellwig return warn_unsupported(in, "read"); 910*aa3dbde8SDavid Howells /* 911*aa3dbde8SDavid Howells * O_DIRECT doesn't deal with the pagecache, so we allocate a buffer, 912*aa3dbde8SDavid Howells * copy into it and splice that into the pipe. 913*aa3dbde8SDavid Howells */ 914*aa3dbde8SDavid Howells if ((in->f_flags & O_DIRECT)) 915*aa3dbde8SDavid Howells return copy_splice_read(in, ppos, pipe, len, flags); 9162bc01060SChristoph Hellwig return in->f_op->splice_read(in, ppos, pipe, len, flags); 9175274f052SJens Axboe } 9186a3f30b8SDavid Howells EXPORT_SYMBOL_GPL(vfs_splice_read); 9195274f052SJens Axboe 920932cc6d4SJens Axboe /** 921932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 922932cc6d4SJens Axboe * @in: file to splice from 923932cc6d4SJens Axboe * @sd: actor information on where to splice to 924932cc6d4SJens Axboe * @actor: handles the data splicing 925932cc6d4SJens Axboe * 926932cc6d4SJens Axboe * Description: 927932cc6d4SJens Axboe * This is a special case helper to splice directly between two 928932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 929932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 930932cc6d4SJens Axboe * that process. 931932cc6d4SJens Axboe * 932c66ab6faSJens Axboe */ 933c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 934c66ab6faSJens Axboe splice_direct_actor *actor) 935b92ce558SJens Axboe { 936b92ce558SJens Axboe struct pipe_inode_info *pipe; 937b92ce558SJens Axboe long ret, bytes; 938c66ab6faSJens Axboe size_t len; 9390ff28d9fSChristophe Leroy int i, flags, more; 940b92ce558SJens Axboe 941b92ce558SJens Axboe /* 94297ef77c5SJason A. Donenfeld * We require the input to be seekable, as we don't want to randomly 94397ef77c5SJason A. Donenfeld * drop data for eg socket -> socket splicing. Use the piped splicing 94497ef77c5SJason A. Donenfeld * for that! 945b92ce558SJens Axboe */ 94697ef77c5SJason A. Donenfeld if (unlikely(!(in->f_mode & FMODE_LSEEK))) 947b92ce558SJens Axboe return -EINVAL; 948b92ce558SJens Axboe 949b92ce558SJens Axboe /* 950b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 951b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 952b92ce558SJens Axboe */ 953b92ce558SJens Axboe pipe = current->splice_pipe; 95449570e9bSJens Axboe if (unlikely(!pipe)) { 9557bee130eSAl Viro pipe = alloc_pipe_info(); 956b92ce558SJens Axboe if (!pipe) 957b92ce558SJens Axboe return -ENOMEM; 958b92ce558SJens Axboe 959b92ce558SJens Axboe /* 960b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 96100522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 962b92ce558SJens Axboe * PIPE_READERS appropriately. 963b92ce558SJens Axboe */ 964b92ce558SJens Axboe pipe->readers = 1; 965b92ce558SJens Axboe 966b92ce558SJens Axboe current->splice_pipe = pipe; 967b92ce558SJens Axboe } 968b92ce558SJens Axboe 969b92ce558SJens Axboe /* 97073d62d83SIngo Molnar * Do the splice. 971b92ce558SJens Axboe */ 972b92ce558SJens Axboe bytes = 0; 973c66ab6faSJens Axboe len = sd->total_len; 974c66ab6faSJens Axboe flags = sd->flags; 975c66ab6faSJens Axboe 976c66ab6faSJens Axboe /* 977c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 978c66ab6faSJens Axboe */ 979c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 9800ff28d9fSChristophe Leroy more = sd->flags & SPLICE_F_MORE; 981b92ce558SJens Axboe 9828cefc107SDavid Howells WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); 98317614445SDarrick J. Wong 984b92ce558SJens Axboe while (len) { 98551a92c0fSJens Axboe size_t read_len; 986a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 987b92ce558SJens Axboe 9886a3f30b8SDavid Howells ret = vfs_splice_read(in, &pos, pipe, len, flags); 98951a92c0fSJens Axboe if (unlikely(ret <= 0)) 990b92ce558SJens Axboe goto out_release; 991b92ce558SJens Axboe 992b92ce558SJens Axboe read_len = ret; 993c66ab6faSJens Axboe sd->total_len = read_len; 994b92ce558SJens Axboe 995b92ce558SJens Axboe /* 9960ff28d9fSChristophe Leroy * If more data is pending, set SPLICE_F_MORE 9970ff28d9fSChristophe Leroy * If this is the last data and SPLICE_F_MORE was not set 9980ff28d9fSChristophe Leroy * initially, clears it. 9990ff28d9fSChristophe Leroy */ 10000ff28d9fSChristophe Leroy if (read_len < len) 10010ff28d9fSChristophe Leroy sd->flags |= SPLICE_F_MORE; 10020ff28d9fSChristophe Leroy else if (!more) 10030ff28d9fSChristophe Leroy sd->flags &= ~SPLICE_F_MORE; 10040ff28d9fSChristophe Leroy /* 1005b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1006b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1007b92ce558SJens Axboe * could get stuck data in the internal pipe: 1008b92ce558SJens Axboe */ 1009c66ab6faSJens Axboe ret = actor(pipe, sd); 1010a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1011a82c53a0STom Zanussi sd->pos = prev_pos; 1012b92ce558SJens Axboe goto out_release; 1013a82c53a0STom Zanussi } 1014b92ce558SJens Axboe 1015b92ce558SJens Axboe bytes += ret; 1016b92ce558SJens Axboe len -= ret; 1017bcd4f3acSJens Axboe sd->pos = pos; 1018b92ce558SJens Axboe 1019a82c53a0STom Zanussi if (ret < read_len) { 1020a82c53a0STom Zanussi sd->pos = prev_pos + ret; 102151a92c0fSJens Axboe goto out_release; 1022b92ce558SJens Axboe } 1023a82c53a0STom Zanussi } 1024b92ce558SJens Axboe 10259e97198dSJens Axboe done: 10268cefc107SDavid Howells pipe->tail = pipe->head = 0; 10279e97198dSJens Axboe file_accessed(in); 1028b92ce558SJens Axboe return bytes; 1029b92ce558SJens Axboe 1030b92ce558SJens Axboe out_release: 1031b92ce558SJens Axboe /* 1032b92ce558SJens Axboe * If we did an incomplete transfer we must release 1033b92ce558SJens Axboe * the pipe buffers in question: 1034b92ce558SJens Axboe */ 10358cefc107SDavid Howells for (i = 0; i < pipe->ring_size; i++) { 10368cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[i]; 1037b92ce558SJens Axboe 1038a779638cSMiklos Szeredi if (buf->ops) 1039a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 1040b92ce558SJens Axboe } 1041b92ce558SJens Axboe 10429e97198dSJens Axboe if (!bytes) 10439e97198dSJens Axboe bytes = ret; 1044b92ce558SJens Axboe 10459e97198dSJens Axboe goto done; 1046c66ab6faSJens Axboe } 1047c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1048c66ab6faSJens Axboe 1049c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1050c66ab6faSJens Axboe struct splice_desc *sd) 1051c66ab6faSJens Axboe { 10526a14b90bSJens Axboe struct file *file = sd->u.file; 1053c66ab6faSJens Axboe 10547995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 10552cb4b05eSChangli Gao sd->flags); 1056c66ab6faSJens Axboe } 1057c66ab6faSJens Axboe 1058932cc6d4SJens Axboe /** 1059932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1060932cc6d4SJens Axboe * @in: file to splice from 1061932cc6d4SJens Axboe * @ppos: input file offset 1062932cc6d4SJens Axboe * @out: file to splice to 1063acdb37c3SRandy Dunlap * @opos: output file offset 1064932cc6d4SJens Axboe * @len: number of bytes to splice 1065932cc6d4SJens Axboe * @flags: splice modifier flags 1066932cc6d4SJens Axboe * 1067932cc6d4SJens Axboe * Description: 1068932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1069932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1070932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1071932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1072932cc6d4SJens Axboe * 1073932cc6d4SJens Axboe */ 1074c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 10757995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1076c66ab6faSJens Axboe { 1077c66ab6faSJens Axboe struct splice_desc sd = { 1078c66ab6faSJens Axboe .len = len, 1079c66ab6faSJens Axboe .total_len = len, 1080c66ab6faSJens Axboe .flags = flags, 1081c66ab6faSJens Axboe .pos = *ppos, 10826a14b90bSJens Axboe .u.file = out, 10837995bd28SAl Viro .opos = opos, 1084c66ab6faSJens Axboe }; 108551a92c0fSJens Axboe long ret; 1086c66ab6faSJens Axboe 108718c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 108818c67cb9SAl Viro return -EBADF; 108918c67cb9SAl Viro 109018c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 109118c67cb9SAl Viro return -EINVAL; 109218c67cb9SAl Viro 109318c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 109418c67cb9SAl Viro if (unlikely(ret < 0)) 109518c67cb9SAl Viro return ret; 109618c67cb9SAl Viro 1097c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 109851a92c0fSJens Axboe if (ret > 0) 1099a82c53a0STom Zanussi *ppos = sd.pos; 110051a92c0fSJens Axboe 1101c66ab6faSJens Axboe return ret; 1102b92ce558SJens Axboe } 11031c118596SMiklos Szeredi EXPORT_SYMBOL(do_splice_direct); 1104b92ce558SJens Axboe 11058924feffSAl Viro static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) 11068924feffSAl Viro { 110752bce911SLinus Torvalds for (;;) { 110852bce911SLinus Torvalds if (unlikely(!pipe->readers)) { 110952bce911SLinus Torvalds send_sig(SIGPIPE, current, 0); 111052bce911SLinus Torvalds return -EPIPE; 111152bce911SLinus Torvalds } 11126718b6f8SDavid Howells if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 111352bce911SLinus Torvalds return 0; 11148924feffSAl Viro if (flags & SPLICE_F_NONBLOCK) 11158924feffSAl Viro return -EAGAIN; 11168924feffSAl Viro if (signal_pending(current)) 11178924feffSAl Viro return -ERESTARTSYS; 1118472e5b05SLinus Torvalds pipe_wait_writable(pipe); 11198924feffSAl Viro } 11208924feffSAl Viro } 11218924feffSAl Viro 11227c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 11237c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 11247c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1125ddac0d39SJens Axboe 1126b964bf53SAl Viro long splice_file_to_pipe(struct file *in, 1127faa97c48SAl Viro struct pipe_inode_info *opipe, 1128faa97c48SAl Viro loff_t *offset, 1129faa97c48SAl Viro size_t len, unsigned int flags) 1130faa97c48SAl Viro { 1131faa97c48SAl Viro long ret; 1132faa97c48SAl Viro 1133faa97c48SAl Viro pipe_lock(opipe); 1134faa97c48SAl Viro ret = wait_for_space(opipe, flags); 1135faa97c48SAl Viro if (!ret) 11366a3f30b8SDavid Howells ret = vfs_splice_read(in, offset, opipe, len, flags); 1137faa97c48SAl Viro pipe_unlock(opipe); 1138faa97c48SAl Viro if (ret > 0) 1139faa97c48SAl Viro wakeup_pipe_readers(opipe); 1140faa97c48SAl Viro return ret; 1141faa97c48SAl Viro } 1142faa97c48SAl Viro 1143ddac0d39SJens Axboe /* 114483f9135bSJens Axboe * Determine where to splice to/from. 114583f9135bSJens Axboe */ 1146ee6e00c8SJens Axboe long do_splice(struct file *in, loff_t *off_in, struct file *out, 1147ee6e00c8SJens Axboe loff_t *off_out, size_t len, unsigned int flags) 11485274f052SJens Axboe { 11497c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 11507c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 11517995bd28SAl Viro loff_t offset; 1152a4514ebdSJens Axboe long ret; 11535274f052SJens Axboe 115490da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 115590da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 115690da2e3fSPavel Begunkov return -EBADF; 115790da2e3fSPavel Begunkov 1158c73be61cSDavid Howells ipipe = get_pipe_info(in, true); 1159c73be61cSDavid Howells opipe = get_pipe_info(out, true); 11607c77f0b3SMiklos Szeredi 11617c77f0b3SMiklos Szeredi if (ipipe && opipe) { 11627c77f0b3SMiklos Szeredi if (off_in || off_out) 11637c77f0b3SMiklos Szeredi return -ESPIPE; 11647c77f0b3SMiklos Szeredi 11657c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 11667c77f0b3SMiklos Szeredi if (ipipe == opipe) 11677c77f0b3SMiklos Szeredi return -EINVAL; 11687c77f0b3SMiklos Szeredi 1169ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1170ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1171ee5e0011SSlavomir Kaslev 11727c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 11737c77f0b3SMiklos Szeredi } 11747c77f0b3SMiklos Szeredi 11757c77f0b3SMiklos Szeredi if (ipipe) { 1176529565dcSIngo Molnar if (off_in) 1177529565dcSIngo Molnar return -ESPIPE; 1178b92ce558SJens Axboe if (off_out) { 117919c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1180b92ce558SJens Axboe return -EINVAL; 1181ee6e00c8SJens Axboe offset = *off_out; 11827995bd28SAl Viro } else { 11837995bd28SAl Viro offset = out->f_pos; 11847995bd28SAl Viro } 1185529565dcSIngo Molnar 118618c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 118718c67cb9SAl Viro return -EINVAL; 118818c67cb9SAl Viro 118918c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 119018c67cb9SAl Viro if (unlikely(ret < 0)) 119118c67cb9SAl Viro return ret; 119218c67cb9SAl Viro 1193ee5e0011SSlavomir Kaslev if (in->f_flags & O_NONBLOCK) 1194ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1195ee5e0011SSlavomir Kaslev 1196500368f7SAl Viro file_start_write(out); 11977995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1198500368f7SAl Viro file_end_write(out); 1199a4514ebdSJens Axboe 1200983652c6SChung-Chiang Cheng if (ret > 0) 1201983652c6SChung-Chiang Cheng fsnotify_modify(out); 1202983652c6SChung-Chiang Cheng 12037995bd28SAl Viro if (!off_out) 12047995bd28SAl Viro out->f_pos = offset; 1205ee6e00c8SJens Axboe else 1206ee6e00c8SJens Axboe *off_out = offset; 1207a4514ebdSJens Axboe 1208a4514ebdSJens Axboe return ret; 1209529565dcSIngo Molnar } 12105274f052SJens Axboe 12117c77f0b3SMiklos Szeredi if (opipe) { 1212529565dcSIngo Molnar if (off_out) 1213529565dcSIngo Molnar return -ESPIPE; 1214b92ce558SJens Axboe if (off_in) { 121519c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1216b92ce558SJens Axboe return -EINVAL; 1217ee6e00c8SJens Axboe offset = *off_in; 12187995bd28SAl Viro } else { 12197995bd28SAl Viro offset = in->f_pos; 12207995bd28SAl Viro } 1221529565dcSIngo Molnar 1222ee5e0011SSlavomir Kaslev if (out->f_flags & O_NONBLOCK) 1223ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1224ee5e0011SSlavomir Kaslev 1225faa97c48SAl Viro ret = splice_file_to_pipe(in, opipe, &offset, len, flags); 1226983652c6SChung-Chiang Cheng 1227983652c6SChung-Chiang Cheng if (ret > 0) 1228983652c6SChung-Chiang Cheng fsnotify_access(in); 1229983652c6SChung-Chiang Cheng 12307995bd28SAl Viro if (!off_in) 12317995bd28SAl Viro in->f_pos = offset; 1232ee6e00c8SJens Axboe else 1233ee6e00c8SJens Axboe *off_in = offset; 1234a4514ebdSJens Axboe 1235a4514ebdSJens Axboe return ret; 1236529565dcSIngo Molnar } 12375274f052SJens Axboe 12385274f052SJens Axboe return -EINVAL; 12395274f052SJens Axboe } 12405274f052SJens Axboe 1241ee6e00c8SJens Axboe static long __do_splice(struct file *in, loff_t __user *off_in, 1242ee6e00c8SJens Axboe struct file *out, loff_t __user *off_out, 1243ee6e00c8SJens Axboe size_t len, unsigned int flags) 1244ee6e00c8SJens Axboe { 1245ee6e00c8SJens Axboe struct pipe_inode_info *ipipe; 1246ee6e00c8SJens Axboe struct pipe_inode_info *opipe; 1247ee6e00c8SJens Axboe loff_t offset, *__off_in = NULL, *__off_out = NULL; 1248ee6e00c8SJens Axboe long ret; 1249ee6e00c8SJens Axboe 1250ee6e00c8SJens Axboe ipipe = get_pipe_info(in, true); 1251ee6e00c8SJens Axboe opipe = get_pipe_info(out, true); 1252ee6e00c8SJens Axboe 12530f99fc51SJens Axboe if (ipipe) { 12540f99fc51SJens Axboe if (off_in) 1255ee6e00c8SJens Axboe return -ESPIPE; 12560f99fc51SJens Axboe pipe_clear_nowait(in); 12570f99fc51SJens Axboe } 12580f99fc51SJens Axboe if (opipe) { 12590f99fc51SJens Axboe if (off_out) 1260ee6e00c8SJens Axboe return -ESPIPE; 12610f99fc51SJens Axboe pipe_clear_nowait(out); 12620f99fc51SJens Axboe } 1263ee6e00c8SJens Axboe 1264ee6e00c8SJens Axboe if (off_out) { 1265ee6e00c8SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1266ee6e00c8SJens Axboe return -EFAULT; 1267ee6e00c8SJens Axboe __off_out = &offset; 1268ee6e00c8SJens Axboe } 1269ee6e00c8SJens Axboe if (off_in) { 1270ee6e00c8SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1271ee6e00c8SJens Axboe return -EFAULT; 1272ee6e00c8SJens Axboe __off_in = &offset; 1273ee6e00c8SJens Axboe } 1274ee6e00c8SJens Axboe 1275ee6e00c8SJens Axboe ret = do_splice(in, __off_in, out, __off_out, len, flags); 1276ee6e00c8SJens Axboe if (ret < 0) 1277ee6e00c8SJens Axboe return ret; 1278ee6e00c8SJens Axboe 1279ee6e00c8SJens Axboe if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) 1280ee6e00c8SJens Axboe return -EFAULT; 1281ee6e00c8SJens Axboe if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) 1282ee6e00c8SJens Axboe return -EFAULT; 1283ee6e00c8SJens Axboe 1284ee6e00c8SJens Axboe return ret; 1285ee6e00c8SJens Axboe } 1286ee6e00c8SJens Axboe 128779fddc4eSAl Viro static int iter_to_pipe(struct iov_iter *from, 128879fddc4eSAl Viro struct pipe_inode_info *pipe, 128979fddc4eSAl Viro unsigned flags) 1290912d35f8SJens Axboe { 129179fddc4eSAl Viro struct pipe_buffer buf = { 129279fddc4eSAl Viro .ops = &user_page_pipe_buf_ops, 129379fddc4eSAl Viro .flags = flags 129479fddc4eSAl Viro }; 129579fddc4eSAl Viro size_t total = 0; 129679fddc4eSAl Viro int ret = 0; 129779fddc4eSAl Viro 12987d690c15SAl Viro while (iov_iter_count(from)) { 129979fddc4eSAl Viro struct page *pages[16]; 13007d690c15SAl Viro ssize_t left; 1301db85a9ebSAl Viro size_t start; 13027d690c15SAl Viro int i, n; 1303912d35f8SJens Axboe 13047d690c15SAl Viro left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); 13057d690c15SAl Viro if (left <= 0) { 13067d690c15SAl Viro ret = left; 130779fddc4eSAl Viro break; 130879fddc4eSAl Viro } 1309912d35f8SJens Axboe 13107d690c15SAl Viro n = DIV_ROUND_UP(left + start, PAGE_SIZE); 13117d690c15SAl Viro for (i = 0; i < n; i++) { 13127d690c15SAl Viro int size = min_t(int, left, PAGE_SIZE - start); 13137d690c15SAl Viro 13147d690c15SAl Viro buf.page = pages[i]; 131579fddc4eSAl Viro buf.offset = start; 131679fddc4eSAl Viro buf.len = size; 131779fddc4eSAl Viro ret = add_to_pipe(pipe, &buf); 131879fddc4eSAl Viro if (unlikely(ret < 0)) { 13197d690c15SAl Viro iov_iter_revert(from, left); 13207d690c15SAl Viro // this one got dropped by add_to_pipe() 13217d690c15SAl Viro while (++i < n) 13227d690c15SAl Viro put_page(pages[i]); 13237d690c15SAl Viro goto out; 13247d690c15SAl Viro } 132579fddc4eSAl Viro total += ret; 13267d690c15SAl Viro left -= size; 13277d690c15SAl Viro start = 0; 1328912d35f8SJens Axboe } 1329912d35f8SJens Axboe } 13307d690c15SAl Viro out: 133179fddc4eSAl Viro return total ? total : ret; 1332912d35f8SJens Axboe } 1333912d35f8SJens Axboe 13346a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 13356a14b90bSJens Axboe struct splice_desc *sd) 13366a14b90bSJens Axboe { 13376130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 13386130f531SAl Viro return n == sd->len ? n : -EFAULT; 13396a14b90bSJens Axboe } 13406a14b90bSJens Axboe 13416a14b90bSJens Axboe /* 13426a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13436a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13446a14b90bSJens Axboe */ 134587a3002aSAl Viro static long vmsplice_to_user(struct file *file, struct iov_iter *iter, 134687a3002aSAl Viro unsigned int flags) 13476a14b90bSJens Axboe { 1348c73be61cSDavid Howells struct pipe_inode_info *pipe = get_pipe_info(file, true); 134987a3002aSAl Viro struct splice_desc sd = { 135087a3002aSAl Viro .total_len = iov_iter_count(iter), 135187a3002aSAl Viro .flags = flags, 135287a3002aSAl Viro .u.data = iter 135387a3002aSAl Viro }; 135487a3002aSAl Viro long ret = 0; 13556a14b90bSJens Axboe 13566a14b90bSJens Axboe if (!pipe) 13576a14b90bSJens Axboe return -EBADF; 13586a14b90bSJens Axboe 13590f99fc51SJens Axboe pipe_clear_nowait(file); 13600f99fc51SJens Axboe 1361345995faSAl Viro if (sd.total_len) { 13626130f531SAl Viro pipe_lock(pipe); 13636130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 136461e0d47cSMiklos Szeredi pipe_unlock(pipe); 1365345995faSAl Viro } 13666a14b90bSJens Axboe 13676a14b90bSJens Axboe return ret; 13686a14b90bSJens Axboe } 13696a14b90bSJens Axboe 1370912d35f8SJens Axboe /* 1371912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1372912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1373912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1374912d35f8SJens Axboe */ 137587a3002aSAl Viro static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, 137687a3002aSAl Viro unsigned int flags) 1377912d35f8SJens Axboe { 1378ddac0d39SJens Axboe struct pipe_inode_info *pipe; 137987a3002aSAl Viro long ret = 0; 138079fddc4eSAl Viro unsigned buf_flag = 0; 138179fddc4eSAl Viro 138279fddc4eSAl Viro if (flags & SPLICE_F_GIFT) 138379fddc4eSAl Viro buf_flag = PIPE_BUF_FLAG_GIFT; 1384912d35f8SJens Axboe 1385c73be61cSDavid Howells pipe = get_pipe_info(file, true); 1386ddac0d39SJens Axboe if (!pipe) 1387912d35f8SJens Axboe return -EBADF; 1388912d35f8SJens Axboe 13890f99fc51SJens Axboe pipe_clear_nowait(file); 13900f99fc51SJens Axboe 13918924feffSAl Viro pipe_lock(pipe); 13928924feffSAl Viro ret = wait_for_space(pipe, flags); 139379fddc4eSAl Viro if (!ret) 139487a3002aSAl Viro ret = iter_to_pipe(iter, pipe, buf_flag); 13958924feffSAl Viro pipe_unlock(pipe); 13968924feffSAl Viro if (ret > 0) 13978924feffSAl Viro wakeup_pipe_readers(pipe); 139835f3d14dSJens Axboe return ret; 1399912d35f8SJens Axboe } 1400912d35f8SJens Axboe 140187a3002aSAl Viro static int vmsplice_type(struct fd f, int *type) 140287a3002aSAl Viro { 140387a3002aSAl Viro if (!f.file) 140487a3002aSAl Viro return -EBADF; 140587a3002aSAl Viro if (f.file->f_mode & FMODE_WRITE) { 1406de4eda9dSAl Viro *type = ITER_SOURCE; 140787a3002aSAl Viro } else if (f.file->f_mode & FMODE_READ) { 1408de4eda9dSAl Viro *type = ITER_DEST; 140987a3002aSAl Viro } else { 141087a3002aSAl Viro fdput(f); 141187a3002aSAl Viro return -EBADF; 141287a3002aSAl Viro } 141387a3002aSAl Viro return 0; 141487a3002aSAl Viro } 141587a3002aSAl Viro 14166a14b90bSJens Axboe /* 14176a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 14186a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 14196a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 14206a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 14216a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 14226a14b90bSJens Axboe * solutions for that: 14236a14b90bSJens Axboe * 14246a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 14256a14b90bSJens Axboe * do a regular read() on the buffer anyway. 14266a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 14276a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 14286a14b90bSJens Axboe * 14296a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 14306a14b90bSJens Axboe * 14316a14b90bSJens Axboe */ 143287a3002aSAl Viro SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, 143330cfe4efSDominik Brodowski unsigned long, nr_segs, unsigned int, flags) 143430cfe4efSDominik Brodowski { 143587a3002aSAl Viro struct iovec iovstack[UIO_FASTIOV]; 143687a3002aSAl Viro struct iovec *iov = iovstack; 143787a3002aSAl Viro struct iov_iter iter; 143887e5e6daSJens Axboe ssize_t error; 143987a3002aSAl Viro struct fd f; 144087a3002aSAl Viro int type; 144187a3002aSAl Viro 1442598b3cecSChristoph Hellwig if (unlikely(flags & ~SPLICE_F_ALL)) 1443598b3cecSChristoph Hellwig return -EINVAL; 1444598b3cecSChristoph Hellwig 144587a3002aSAl Viro f = fdget(fd); 144687a3002aSAl Viro error = vmsplice_type(f, &type); 144787a3002aSAl Viro if (error) 144887a3002aSAl Viro return error; 144987a3002aSAl Viro 145087a3002aSAl Viro error = import_iovec(type, uiov, nr_segs, 145187a3002aSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 1452598b3cecSChristoph Hellwig if (error < 0) 1453598b3cecSChristoph Hellwig goto out_fdput; 1454598b3cecSChristoph Hellwig 1455598b3cecSChristoph Hellwig if (!iov_iter_count(&iter)) 1456598b3cecSChristoph Hellwig error = 0; 1457de4eda9dSAl Viro else if (type == ITER_SOURCE) 1458598b3cecSChristoph Hellwig error = vmsplice_to_pipe(f.file, &iter, flags); 1459598b3cecSChristoph Hellwig else 1460598b3cecSChristoph Hellwig error = vmsplice_to_user(f.file, &iter, flags); 1461598b3cecSChristoph Hellwig 146287a3002aSAl Viro kfree(iov); 1463598b3cecSChristoph Hellwig out_fdput: 146487a3002aSAl Viro fdput(f); 146587a3002aSAl Viro return error; 146630cfe4efSDominik Brodowski } 146730cfe4efSDominik Brodowski 1468836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1469836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1470836f92adSHeiko Carstens size_t, len, unsigned int, flags) 14715274f052SJens Axboe { 14722903ff01SAl Viro struct fd in, out; 14735274f052SJens Axboe long error; 14745274f052SJens Axboe 14755274f052SJens Axboe if (unlikely(!len)) 14765274f052SJens Axboe return 0; 14775274f052SJens Axboe 14783d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 14793d6ea290SAl Viro return -EINVAL; 14803d6ea290SAl Viro 14815274f052SJens Axboe error = -EBADF; 14822903ff01SAl Viro in = fdget(fd_in); 14832903ff01SAl Viro if (in.file) { 14842903ff01SAl Viro out = fdget(fd_out); 14852903ff01SAl Viro if (out.file) { 1486ee6e00c8SJens Axboe error = __do_splice(in.file, off_in, out.file, off_out, 1487529565dcSIngo Molnar len, flags); 14882903ff01SAl Viro fdput(out); 14895274f052SJens Axboe } 14902903ff01SAl Viro fdput(in); 14915274f052SJens Axboe } 14925274f052SJens Axboe return error; 14935274f052SJens Axboe } 149470524490SJens Axboe 149570524490SJens Axboe /* 1496aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1497aadd06e5SJens Axboe * return an appropriate error. 1498aadd06e5SJens Axboe */ 14997c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1500aadd06e5SJens Axboe { 1501aadd06e5SJens Axboe int ret; 1502aadd06e5SJens Axboe 1503aadd06e5SJens Axboe /* 15048cefc107SDavid Howells * Check the pipe occupancy without the inode lock first. This function 1505aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1506aadd06e5SJens Axboe */ 15078cefc107SDavid Howells if (!pipe_empty(pipe->head, pipe->tail)) 1508aadd06e5SJens Axboe return 0; 1509aadd06e5SJens Axboe 1510aadd06e5SJens Axboe ret = 0; 151161e0d47cSMiklos Szeredi pipe_lock(pipe); 1512aadd06e5SJens Axboe 15138cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 1514aadd06e5SJens Axboe if (signal_pending(current)) { 1515aadd06e5SJens Axboe ret = -ERESTARTSYS; 1516aadd06e5SJens Axboe break; 1517aadd06e5SJens Axboe } 1518aadd06e5SJens Axboe if (!pipe->writers) 1519aadd06e5SJens Axboe break; 1520aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1521aadd06e5SJens Axboe ret = -EAGAIN; 1522aadd06e5SJens Axboe break; 1523aadd06e5SJens Axboe } 1524472e5b05SLinus Torvalds pipe_wait_readable(pipe); 1525aadd06e5SJens Axboe } 1526aadd06e5SJens Axboe 152761e0d47cSMiklos Szeredi pipe_unlock(pipe); 1528aadd06e5SJens Axboe return ret; 1529aadd06e5SJens Axboe } 1530aadd06e5SJens Axboe 1531aadd06e5SJens Axboe /* 1532aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1533aadd06e5SJens Axboe * return an appropriate error. 1534aadd06e5SJens Axboe */ 15357c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1536aadd06e5SJens Axboe { 1537aadd06e5SJens Axboe int ret; 1538aadd06e5SJens Axboe 1539aadd06e5SJens Axboe /* 15408cefc107SDavid Howells * Check pipe occupancy without the inode lock first. This function 1541aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1542aadd06e5SJens Axboe */ 1543566d1362STetsuo Handa if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 1544aadd06e5SJens Axboe return 0; 1545aadd06e5SJens Axboe 1546aadd06e5SJens Axboe ret = 0; 154761e0d47cSMiklos Szeredi pipe_lock(pipe); 1548aadd06e5SJens Axboe 15496718b6f8SDavid Howells while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 1550aadd06e5SJens Axboe if (!pipe->readers) { 1551aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1552aadd06e5SJens Axboe ret = -EPIPE; 1553aadd06e5SJens Axboe break; 1554aadd06e5SJens Axboe } 1555aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1556aadd06e5SJens Axboe ret = -EAGAIN; 1557aadd06e5SJens Axboe break; 1558aadd06e5SJens Axboe } 1559aadd06e5SJens Axboe if (signal_pending(current)) { 1560aadd06e5SJens Axboe ret = -ERESTARTSYS; 1561aadd06e5SJens Axboe break; 1562aadd06e5SJens Axboe } 1563472e5b05SLinus Torvalds pipe_wait_writable(pipe); 1564aadd06e5SJens Axboe } 1565aadd06e5SJens Axboe 156661e0d47cSMiklos Szeredi pipe_unlock(pipe); 1567aadd06e5SJens Axboe return ret; 1568aadd06e5SJens Axboe } 1569aadd06e5SJens Axboe 1570aadd06e5SJens Axboe /* 15717c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 15727c77f0b3SMiklos Szeredi */ 15737c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 15747c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 15757c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 15767c77f0b3SMiklos Szeredi { 15777c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 15788cefc107SDavid Howells unsigned int i_head, o_head; 15798cefc107SDavid Howells unsigned int i_tail, o_tail; 15808cefc107SDavid Howells unsigned int i_mask, o_mask; 15818cefc107SDavid Howells int ret = 0; 15827c77f0b3SMiklos Szeredi bool input_wakeup = false; 15837c77f0b3SMiklos Szeredi 15847c77f0b3SMiklos Szeredi 15857c77f0b3SMiklos Szeredi retry: 15867c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 15877c77f0b3SMiklos Szeredi if (ret) 15887c77f0b3SMiklos Szeredi return ret; 15897c77f0b3SMiklos Szeredi 15907c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 15917c77f0b3SMiklos Szeredi if (ret) 15927c77f0b3SMiklos Szeredi return ret; 15937c77f0b3SMiklos Szeredi 15947c77f0b3SMiklos Szeredi /* 15957c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 15967c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 15977c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 15987c77f0b3SMiklos Szeredi */ 15997c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 16007c77f0b3SMiklos Szeredi 16018cefc107SDavid Howells i_tail = ipipe->tail; 16028cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 16038cefc107SDavid Howells o_head = opipe->head; 16048cefc107SDavid Howells o_mask = opipe->ring_size - 1; 16058cefc107SDavid Howells 16067c77f0b3SMiklos Szeredi do { 16078cefc107SDavid Howells size_t o_len; 16088cefc107SDavid Howells 16097c77f0b3SMiklos Szeredi if (!opipe->readers) { 16107c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 16117c77f0b3SMiklos Szeredi if (!ret) 16127c77f0b3SMiklos Szeredi ret = -EPIPE; 16137c77f0b3SMiklos Szeredi break; 16147c77f0b3SMiklos Szeredi } 16157c77f0b3SMiklos Szeredi 16168cefc107SDavid Howells i_head = ipipe->head; 16178cefc107SDavid Howells o_tail = opipe->tail; 16188cefc107SDavid Howells 16198cefc107SDavid Howells if (pipe_empty(i_head, i_tail) && !ipipe->writers) 16207c77f0b3SMiklos Szeredi break; 16217c77f0b3SMiklos Szeredi 16227c77f0b3SMiklos Szeredi /* 16237c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 16247c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 16257c77f0b3SMiklos Szeredi */ 16268cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 16276718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) { 16287c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 16297c77f0b3SMiklos Szeredi if (ret) 16307c77f0b3SMiklos Szeredi break; 16317c77f0b3SMiklos Szeredi 16327c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 16337c77f0b3SMiklos Szeredi ret = -EAGAIN; 16347c77f0b3SMiklos Szeredi break; 16357c77f0b3SMiklos Szeredi } 16367c77f0b3SMiklos Szeredi 16377c77f0b3SMiklos Szeredi /* 16387c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 16397c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 16407c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 16417c77f0b3SMiklos Szeredi */ 16427c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16437c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16447c77f0b3SMiklos Szeredi goto retry; 16457c77f0b3SMiklos Szeredi } 16467c77f0b3SMiklos Szeredi 16478cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 16488cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 16497c77f0b3SMiklos Szeredi 16507c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 16517c77f0b3SMiklos Szeredi /* 16527c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 16537c77f0b3SMiklos Szeredi */ 16547c77f0b3SMiklos Szeredi *obuf = *ibuf; 16557c77f0b3SMiklos Szeredi ibuf->ops = NULL; 16568cefc107SDavid Howells i_tail++; 16578cefc107SDavid Howells ipipe->tail = i_tail; 16587c77f0b3SMiklos Szeredi input_wakeup = true; 16598cefc107SDavid Howells o_len = obuf->len; 16608cefc107SDavid Howells o_head++; 16618cefc107SDavid Howells opipe->head = o_head; 16627c77f0b3SMiklos Szeredi } else { 16637c77f0b3SMiklos Szeredi /* 16647c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 16657c77f0b3SMiklos Szeredi * so we can copy the contents over. 16667c77f0b3SMiklos Szeredi */ 166715fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 166815fab63eSMatthew Wilcox if (ret == 0) 166915fab63eSMatthew Wilcox ret = -EFAULT; 167015fab63eSMatthew Wilcox break; 167115fab63eSMatthew Wilcox } 16727c77f0b3SMiklos Szeredi *obuf = *ibuf; 16737c77f0b3SMiklos Szeredi 16747c77f0b3SMiklos Szeredi /* 1675f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flags, we need to 16767c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 16777c77f0b3SMiklos Szeredi */ 16787c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1679f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1680a0ce2f0aSJann Horn 16817c77f0b3SMiklos Szeredi obuf->len = len; 16828cefc107SDavid Howells ibuf->offset += len; 16838cefc107SDavid Howells ibuf->len -= len; 16848cefc107SDavid Howells o_len = len; 16858cefc107SDavid Howells o_head++; 16868cefc107SDavid Howells opipe->head = o_head; 16877c77f0b3SMiklos Szeredi } 16888cefc107SDavid Howells ret += o_len; 16898cefc107SDavid Howells len -= o_len; 16907c77f0b3SMiklos Szeredi } while (len); 16917c77f0b3SMiklos Szeredi 16927c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16937c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16947c77f0b3SMiklos Szeredi 16957c77f0b3SMiklos Szeredi /* 16967c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 16977c77f0b3SMiklos Szeredi */ 1698825cdcb1SNamhyung Kim if (ret > 0) 1699825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1700825cdcb1SNamhyung Kim 17017c77f0b3SMiklos Szeredi if (input_wakeup) 17027c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 17037c77f0b3SMiklos Szeredi 17047c77f0b3SMiklos Szeredi return ret; 17057c77f0b3SMiklos Szeredi } 17067c77f0b3SMiklos Szeredi 17077c77f0b3SMiklos Szeredi /* 170870524490SJens Axboe * Link contents of ipipe to opipe. 170970524490SJens Axboe */ 171070524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 171170524490SJens Axboe struct pipe_inode_info *opipe, 171270524490SJens Axboe size_t len, unsigned int flags) 171370524490SJens Axboe { 171470524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 17158cefc107SDavid Howells unsigned int i_head, o_head; 17168cefc107SDavid Howells unsigned int i_tail, o_tail; 17178cefc107SDavid Howells unsigned int i_mask, o_mask; 17188cefc107SDavid Howells int ret = 0; 171970524490SJens Axboe 172070524490SJens Axboe /* 172170524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 172261e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 172370524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 172470524490SJens Axboe */ 172561e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 172670524490SJens Axboe 17278cefc107SDavid Howells i_tail = ipipe->tail; 17288cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 17298cefc107SDavid Howells o_head = opipe->head; 17308cefc107SDavid Howells o_mask = opipe->ring_size - 1; 17318cefc107SDavid Howells 1732aadd06e5SJens Axboe do { 173370524490SJens Axboe if (!opipe->readers) { 173470524490SJens Axboe send_sig(SIGPIPE, current, 0); 173570524490SJens Axboe if (!ret) 173670524490SJens Axboe ret = -EPIPE; 173770524490SJens Axboe break; 173870524490SJens Axboe } 173970524490SJens Axboe 17408cefc107SDavid Howells i_head = ipipe->head; 17418cefc107SDavid Howells o_tail = opipe->tail; 17428cefc107SDavid Howells 174370524490SJens Axboe /* 17448cefc107SDavid Howells * If we have iterated all input buffers or run out of 1745aadd06e5SJens Axboe * output room, break. 174670524490SJens Axboe */ 17478cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 17486718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) 1749aadd06e5SJens Axboe break; 1750aadd06e5SJens Axboe 17518cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 17528cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 175370524490SJens Axboe 175470524490SJens Axboe /* 175570524490SJens Axboe * Get a reference to this pipe buffer, 175670524490SJens Axboe * so we can copy the contents over. 175770524490SJens Axboe */ 175815fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 175915fab63eSMatthew Wilcox if (ret == 0) 176015fab63eSMatthew Wilcox ret = -EFAULT; 176115fab63eSMatthew Wilcox break; 176215fab63eSMatthew Wilcox } 176370524490SJens Axboe 176470524490SJens Axboe *obuf = *ibuf; 176570524490SJens Axboe 17667afa6fd0SJens Axboe /* 1767f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flag, we need to prevent 1768f6dd9755SChristoph Hellwig * multiple steals of this page. 17697afa6fd0SJens Axboe */ 17707afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1771f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1772a0ce2f0aSJann Horn 177370524490SJens Axboe if (obuf->len > len) 177470524490SJens Axboe obuf->len = len; 177570524490SJens Axboe ret += obuf->len; 177670524490SJens Axboe len -= obuf->len; 17778cefc107SDavid Howells 17788cefc107SDavid Howells o_head++; 17798cefc107SDavid Howells opipe->head = o_head; 17808cefc107SDavid Howells i_tail++; 1781aadd06e5SJens Axboe } while (len); 178270524490SJens Axboe 178361e0d47cSMiklos Szeredi pipe_unlock(ipipe); 178461e0d47cSMiklos Szeredi pipe_unlock(opipe); 178570524490SJens Axboe 1786aadd06e5SJens Axboe /* 1787aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1788aadd06e5SJens Axboe */ 1789825cdcb1SNamhyung Kim if (ret > 0) 1790825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 179170524490SJens Axboe 179270524490SJens Axboe return ret; 179370524490SJens Axboe } 179470524490SJens Axboe 179570524490SJens Axboe /* 179670524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 179770524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 179870524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 179970524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 180070524490SJens Axboe */ 18019dafdfc2SPavel Begunkov long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) 180270524490SJens Axboe { 1803c73be61cSDavid Howells struct pipe_inode_info *ipipe = get_pipe_info(in, true); 1804c73be61cSDavid Howells struct pipe_inode_info *opipe = get_pipe_info(out, true); 1805aadd06e5SJens Axboe int ret = -EINVAL; 180670524490SJens Axboe 180790da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 180890da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 180990da2e3fSPavel Begunkov return -EBADF; 181090da2e3fSPavel Begunkov 181170524490SJens Axboe /* 1812aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1813aadd06e5SJens Axboe * copying the data. 181470524490SJens Axboe */ 1815aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1816ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1817ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1818ee5e0011SSlavomir Kaslev 1819aadd06e5SJens Axboe /* 1820aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1821aadd06e5SJens Axboe * ordering doesn't really matter. 1822aadd06e5SJens Axboe */ 18237c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1824aadd06e5SJens Axboe if (!ret) { 18257c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 182602cf01aeSJens Axboe if (!ret) 1827aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1828aadd06e5SJens Axboe } 1829aadd06e5SJens Axboe } 183070524490SJens Axboe 1831aadd06e5SJens Axboe return ret; 183270524490SJens Axboe } 183370524490SJens Axboe 1834836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 183570524490SJens Axboe { 183690da2e3fSPavel Begunkov struct fd in, out; 18372903ff01SAl Viro int error; 183870524490SJens Axboe 18393d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 18403d6ea290SAl Viro return -EINVAL; 18413d6ea290SAl Viro 184270524490SJens Axboe if (unlikely(!len)) 184370524490SJens Axboe return 0; 184470524490SJens Axboe 184570524490SJens Axboe error = -EBADF; 18462903ff01SAl Viro in = fdget(fdin); 18472903ff01SAl Viro if (in.file) { 184890da2e3fSPavel Begunkov out = fdget(fdout); 18492903ff01SAl Viro if (out.file) { 185090da2e3fSPavel Begunkov error = do_tee(in.file, out.file, len, flags); 18512903ff01SAl Viro fdput(out); 185270524490SJens Axboe } 18532903ff01SAl Viro fdput(in); 185470524490SJens Axboe } 185570524490SJens Axboe 185670524490SJens Axboe return error; 185770524490SJens Axboe } 1858