Thomas Gleixner | 457c899 | 2019-05-19 13:08:55 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 2 | /* |
| 3 | * "splice": joining two ropes together by interweaving their strands. |
| 4 | * |
| 5 | * This is the "extended pipe" functionality, where a pipe is used as |
| 6 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel |
| 7 | * buffer that you can use to transfer data from one end to the other. |
| 8 | * |
| 9 | * The traditional unix read/write is extended with a "splice()" operation |
| 10 | * that transfers data buffers to or from a pipe buffer. |
| 11 | * |
| 12 | * Named by Larry McVoy, original implementation from Linus, extended by |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 13 | * Jens to support splicing to files, network, direct splicing, etc and |
| 14 | * fixing lots of bugs. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 15 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 16 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 17 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
| 18 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 19 | * |
| 20 | */ |
Christoph Hellwig | be29796 | 2016-11-01 07:40:16 -0600 | [diff] [blame] | 21 | #include <linux/bvec.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 22 | #include <linux/fs.h> |
| 23 | #include <linux/file.h> |
| 24 | #include <linux/pagemap.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 25 | #include <linux/splice.h> |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 26 | #include <linux/memcontrol.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 27 | #include <linux/mm_inline.h> |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 28 | #include <linux/swap.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 29 | #include <linux/writeback.h> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 30 | #include <linux/export.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 31 | #include <linux/syscalls.h> |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 32 | #include <linux/uio.h> |
Chung-Chiang Cheng | 983652c | 2023-03-22 14:25:19 +0800 | [diff] [blame] | 33 | #include <linux/fsnotify.h> |
James Morris | 29ce205 | 2007-07-13 11:44:32 +0200 | [diff] [blame] | 34 | #include <linux/security.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 35 | #include <linux/gfp.h> |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 36 | #include <linux/net.h> |
Eric Dumazet | 35f9c09 | 2012-04-05 03:05:35 +0000 | [diff] [blame] | 37 | #include <linux/socket.h> |
Ingo Molnar | 174cd4b | 2017-02-02 19:15:33 +0100 | [diff] [blame] | 38 | #include <linux/sched/signal.h> |
| 39 | |
Al Viro | 06ae43f3 | 2013-03-20 13:19:30 -0400 | [diff] [blame] | 40 | #include "internal.h" |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 41 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 42 | /* |
Jens Axboe | 0f99fc5 | 2023-04-24 16:32:55 -0600 | [diff] [blame] | 43 | * Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to |
| 44 | * indicate they support non-blocking reads or writes, we must clear it |
| 45 | * here if set to avoid blocking other users of this pipe if splice is |
| 46 | * being done on it. |
| 47 | */ |
| 48 | static noinline void noinline pipe_clear_nowait(struct file *file) |
| 49 | { |
| 50 | fmode_t fmode = READ_ONCE(file->f_mode); |
| 51 | |
| 52 | do { |
| 53 | if (!(fmode & FMODE_NOWAIT)) |
| 54 | break; |
| 55 | } while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT)); |
| 56 | } |
| 57 | |
| 58 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 59 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 60 | * a vm helper function, it's already simplified quite a bit by the |
| 61 | * addition of remove_mapping(). If success is returned, the caller may |
| 62 | * attempt to reuse this page for another destination. |
| 63 | */ |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 64 | static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 65 | struct pipe_buffer *buf) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 66 | { |
Matthew Wilcox (Oracle) | 5100da3 | 2022-02-12 22:48:55 -0500 | [diff] [blame] | 67 | struct folio *folio = page_folio(buf->page); |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 68 | struct address_space *mapping; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 69 | |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 70 | folio_lock(folio); |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 71 | |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 72 | mapping = folio_mapping(folio); |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 73 | if (mapping) { |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 74 | WARN_ON(!folio_test_uptodate(folio)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 75 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 76 | /* |
| 77 | * At least for ext2 with nobh option, we need to wait on |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 78 | * writeback completing on this folio, since we'll remove it |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 79 | * from the pagecache. Otherwise truncate wont wait on the |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 80 | * folio, allowing the disk blocks to be reused by someone else |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 81 | * before we actually wrote our data to them. fs corruption |
| 82 | * ensues. |
| 83 | */ |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 84 | folio_wait_writeback(folio); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 85 | |
David Howells | 0201ebf | 2023-06-28 11:48:51 +0100 | [diff] [blame] | 86 | if (!filemap_release_folio(folio, GFP_KERNEL)) |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 87 | goto out_unlock; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 88 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 89 | /* |
| 90 | * If we succeeded in removing the mapping, set LRU flag |
| 91 | * and return good. |
| 92 | */ |
Matthew Wilcox (Oracle) | 5100da3 | 2022-02-12 22:48:55 -0500 | [diff] [blame] | 93 | if (remove_mapping(mapping, folio)) { |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 94 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 95 | return true; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 96 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 97 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 98 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 99 | /* |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 100 | * Raced with truncate or failed to remove folio from current |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 101 | * address space, unlock and return failure. |
| 102 | */ |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 103 | out_unlock: |
Matthew Wilcox (Oracle) | b9ccad2 | 2022-02-11 23:39:03 -0500 | [diff] [blame] | 104 | folio_unlock(folio); |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 105 | return false; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 106 | } |
| 107 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 108 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 109 | struct pipe_buffer *buf) |
| 110 | { |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 111 | put_page(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 112 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 113 | } |
| 114 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 115 | /* |
| 116 | * Check whether the contents of buf is OK to access. Since the content |
| 117 | * is a page cache page, IO may be in flight. |
| 118 | */ |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 119 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 120 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 121 | { |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 122 | struct folio *folio = page_folio(buf->page); |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 123 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 124 | |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 125 | if (!folio_test_uptodate(folio)) { |
| 126 | folio_lock(folio); |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 127 | |
| 128 | /* |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 129 | * Folio got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 130 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 131 | */ |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 132 | if (!folio->mapping) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 133 | err = -ENODATA; |
| 134 | goto error; |
| 135 | } |
| 136 | |
| 137 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 138 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 139 | */ |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 140 | if (!folio_test_uptodate(folio)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 141 | err = -EIO; |
| 142 | goto error; |
| 143 | } |
| 144 | |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 145 | /* Folio is ok after all, we are done */ |
| 146 | folio_unlock(folio); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 147 | } |
| 148 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 149 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 150 | error: |
Matthew Wilcox (Oracle) | 781ca60 | 2023-08-21 15:15:41 +0100 | [diff] [blame] | 151 | folio_unlock(folio); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 152 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 153 | } |
| 154 | |
Hugh Dickins | 708e350 | 2011-07-25 17:12:32 -0700 | [diff] [blame] | 155 | const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 156 | .confirm = page_cache_pipe_buf_confirm, |
| 157 | .release = page_cache_pipe_buf_release, |
| 158 | .try_steal = page_cache_pipe_buf_try_steal, |
| 159 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 160 | }; |
| 161 | |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 162 | static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 163 | struct pipe_buffer *buf) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 164 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 165 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 166 | return false; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 167 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 168 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 169 | return generic_pipe_buf_try_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 170 | } |
| 171 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 172 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 173 | .release = page_cache_pipe_buf_release, |
| 174 | .try_steal = user_page_pipe_buf_try_steal, |
| 175 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 176 | }; |
| 177 | |
Namhyung Kim | 825cdcb | 2011-05-23 19:58:53 +0200 | [diff] [blame] | 178 | static void wakeup_pipe_readers(struct pipe_inode_info *pipe) |
| 179 | { |
| 180 | smp_mb(); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 181 | if (waitqueue_active(&pipe->rd_wait)) |
| 182 | wake_up_interruptible(&pipe->rd_wait); |
Namhyung Kim | 825cdcb | 2011-05-23 19:58:53 +0200 | [diff] [blame] | 183 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 184 | } |
| 185 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 186 | /** |
| 187 | * splice_to_pipe - fill passed data into a pipe |
| 188 | * @pipe: pipe to fill |
| 189 | * @spd: data to fill |
| 190 | * |
| 191 | * Description: |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 192 | * @spd contains a map of pages and len/offset tuples, along with |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 193 | * the struct pipe_buf_operations associated with these pages. This |
| 194 | * function will link that data to the pipe. |
| 195 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 196 | */ |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 197 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 198 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 199 | { |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 200 | unsigned int spd_pages = spd->nr_pages; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 201 | unsigned int tail = pipe->tail; |
| 202 | unsigned int head = pipe->head; |
| 203 | unsigned int mask = pipe->ring_size - 1; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 204 | ssize_t ret = 0; |
| 205 | int page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 206 | |
Rabin Vincent | d6785d9 | 2016-03-10 21:19:06 +0100 | [diff] [blame] | 207 | if (!spd_pages) |
| 208 | return 0; |
| 209 | |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 210 | if (unlikely(!pipe->readers)) { |
| 211 | send_sig(SIGPIPE, current, 0); |
| 212 | ret = -EPIPE; |
| 213 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 214 | } |
| 215 | |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 216 | while (!pipe_full(head, tail, pipe->max_usage)) { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 217 | struct pipe_buffer *buf = &pipe->bufs[head & mask]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 218 | |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 219 | buf->page = spd->pages[page_nr]; |
| 220 | buf->offset = spd->partial[page_nr].offset; |
| 221 | buf->len = spd->partial[page_nr].len; |
| 222 | buf->private = spd->partial[page_nr].private; |
| 223 | buf->ops = spd->ops; |
Miklos Szeredi | 5a81e6a | 2017-02-16 17:49:02 +0100 | [diff] [blame] | 224 | buf->flags = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 225 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 226 | head++; |
| 227 | pipe->head = head; |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 228 | page_nr++; |
| 229 | ret += buf->len; |
| 230 | |
| 231 | if (!--spd->nr_pages) |
| 232 | break; |
| 233 | } |
| 234 | |
| 235 | if (!ret) |
| 236 | ret = -EAGAIN; |
| 237 | |
| 238 | out: |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 239 | while (page_nr < spd_pages) |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 240 | spd->spd_release(spd, page_nr++); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 241 | |
| 242 | return ret; |
| 243 | } |
Hannes Frederic Sowa | 2b51457 | 2015-05-21 17:00:01 +0200 | [diff] [blame] | 244 | EXPORT_SYMBOL_GPL(splice_to_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 245 | |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 246 | ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
| 247 | { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 248 | unsigned int head = pipe->head; |
| 249 | unsigned int tail = pipe->tail; |
| 250 | unsigned int mask = pipe->ring_size - 1; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 251 | int ret; |
| 252 | |
| 253 | if (unlikely(!pipe->readers)) { |
| 254 | send_sig(SIGPIPE, current, 0); |
| 255 | ret = -EPIPE; |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 256 | } else if (pipe_full(head, tail, pipe->max_usage)) { |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 257 | ret = -EAGAIN; |
| 258 | } else { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 259 | pipe->bufs[head & mask] = *buf; |
| 260 | pipe->head = head + 1; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 261 | return buf->len; |
| 262 | } |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 263 | pipe_buf_release(pipe, buf); |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 264 | return ret; |
| 265 | } |
| 266 | EXPORT_SYMBOL(add_to_pipe); |
| 267 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 268 | /* |
| 269 | * Check if we need to grow the arrays holding pages and partial page |
| 270 | * descriptions. |
| 271 | */ |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 272 | int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 273 | { |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 274 | unsigned int max_usage = READ_ONCE(pipe->max_usage); |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 275 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 276 | spd->nr_pages_max = max_usage; |
| 277 | if (max_usage <= PIPE_DEF_BUFFERS) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 278 | return 0; |
| 279 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 280 | spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); |
| 281 | spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), |
Kees Cook | 6da2ec5 | 2018-06-12 13:55:00 -0700 | [diff] [blame] | 282 | GFP_KERNEL); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 283 | |
| 284 | if (spd->pages && spd->partial) |
| 285 | return 0; |
| 286 | |
| 287 | kfree(spd->pages); |
| 288 | kfree(spd->partial); |
| 289 | return -ENOMEM; |
| 290 | } |
| 291 | |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 292 | void splice_shrink_spd(struct splice_pipe_desc *spd) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 293 | { |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 294 | if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 295 | return; |
| 296 | |
| 297 | kfree(spd->pages); |
| 298 | kfree(spd->partial); |
| 299 | } |
| 300 | |
David Howells | 9eee8bd | 2023-05-22 14:50:18 +0100 | [diff] [blame] | 301 | /** |
| 302 | * copy_splice_read - Copy data from a file and splice the copy into a pipe |
| 303 | * @in: The file to read from |
| 304 | * @ppos: Pointer to the file position to read from |
| 305 | * @pipe: The pipe to splice into |
| 306 | * @len: The amount to splice |
| 307 | * @flags: The SPLICE_F_* flags |
| 308 | * |
| 309 | * This function allocates a bunch of pages sufficient to hold the requested |
| 310 | * amount of data (but limited by the remaining pipe capacity), passes it to |
| 311 | * the file's ->read_iter() to read into and then splices the used pages into |
| 312 | * the pipe. |
| 313 | * |
| 314 | * Return: On success, the number of bytes read will be returned and *@ppos |
| 315 | * will be updated if appropriate; 0 will be returned if there is no more data |
| 316 | * to be read; -EAGAIN will be returned if the pipe had no space, and some |
| 317 | * other negative error code will be returned on error. A short read may occur |
| 318 | * if the pipe has insufficient space, we reach the end of the data or we hit a |
| 319 | * hole. |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 320 | */ |
David Howells | 69df79a | 2023-05-22 14:49:50 +0100 | [diff] [blame] | 321 | ssize_t copy_splice_read(struct file *in, loff_t *ppos, |
| 322 | struct pipe_inode_info *pipe, |
| 323 | size_t len, unsigned int flags) |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 324 | { |
| 325 | struct iov_iter to; |
| 326 | struct bio_vec *bv; |
| 327 | struct kiocb kiocb; |
| 328 | struct page **pages; |
| 329 | ssize_t ret; |
David Howells | e69f37b | 2023-05-22 14:49:51 +0100 | [diff] [blame] | 330 | size_t used, npages, chunk, remain, keep = 0; |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 331 | int i; |
| 332 | |
| 333 | /* Work out how much data we can actually add into the pipe */ |
| 334 | used = pipe_occupancy(pipe->head, pipe->tail); |
| 335 | npages = max_t(ssize_t, pipe->max_usage - used, 0); |
| 336 | len = min_t(size_t, len, npages * PAGE_SIZE); |
| 337 | npages = DIV_ROUND_UP(len, PAGE_SIZE); |
| 338 | |
| 339 | bv = kzalloc(array_size(npages, sizeof(bv[0])) + |
| 340 | array_size(npages, sizeof(struct page *)), GFP_KERNEL); |
| 341 | if (!bv) |
| 342 | return -ENOMEM; |
| 343 | |
David Howells | e69f37b | 2023-05-22 14:49:51 +0100 | [diff] [blame] | 344 | pages = (struct page **)(bv + npages); |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 345 | npages = alloc_pages_bulk_array(GFP_USER, npages, pages); |
| 346 | if (!npages) { |
| 347 | kfree(bv); |
| 348 | return -ENOMEM; |
| 349 | } |
| 350 | |
| 351 | remain = len = min_t(size_t, len, npages * PAGE_SIZE); |
| 352 | |
| 353 | for (i = 0; i < npages; i++) { |
| 354 | chunk = min_t(size_t, PAGE_SIZE, remain); |
| 355 | bv[i].bv_page = pages[i]; |
| 356 | bv[i].bv_offset = 0; |
| 357 | bv[i].bv_len = chunk; |
| 358 | remain -= chunk; |
| 359 | } |
| 360 | |
| 361 | /* Do the I/O */ |
| 362 | iov_iter_bvec(&to, ITER_DEST, bv, npages, len); |
| 363 | init_sync_kiocb(&kiocb, in); |
| 364 | kiocb.ki_pos = *ppos; |
Miklos Szeredi | 7c98f7c | 2023-08-28 17:13:18 +0200 | [diff] [blame] | 365 | ret = in->f_op->read_iter(&kiocb, &to); |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 366 | |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 367 | if (ret > 0) { |
David Howells | e69f37b | 2023-05-22 14:49:51 +0100 | [diff] [blame] | 368 | keep = DIV_ROUND_UP(ret, PAGE_SIZE); |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 369 | *ppos = kiocb.ki_pos; |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 370 | } |
| 371 | |
Christoph Hellwig | 2e82f6c | 2023-06-14 16:03:39 +0200 | [diff] [blame] | 372 | /* |
| 373 | * Callers of ->splice_read() expect -EAGAIN on "can't put anything in |
| 374 | * there", rather than -EFAULT. |
| 375 | */ |
| 376 | if (ret == -EFAULT) |
| 377 | ret = -EAGAIN; |
| 378 | |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 379 | /* Free any pages that didn't get touched at all. */ |
David Howells | e69f37b | 2023-05-22 14:49:51 +0100 | [diff] [blame] | 380 | if (keep < npages) |
| 381 | release_pages(pages + keep, npages - keep); |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 382 | |
| 383 | /* Push the remaining pages into the pipe. */ |
David Howells | e69f37b | 2023-05-22 14:49:51 +0100 | [diff] [blame] | 384 | remain = ret; |
| 385 | for (i = 0; i < keep; i++) { |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 386 | struct pipe_buffer *buf = pipe_head_buf(pipe); |
| 387 | |
| 388 | chunk = min_t(size_t, remain, PAGE_SIZE); |
| 389 | *buf = (struct pipe_buffer) { |
| 390 | .ops = &default_pipe_buf_ops, |
| 391 | .page = bv[i].bv_page, |
| 392 | .offset = 0, |
| 393 | .len = chunk, |
| 394 | }; |
| 395 | pipe->head++; |
| 396 | remain -= chunk; |
| 397 | } |
| 398 | |
| 399 | kfree(bv); |
| 400 | return ret; |
| 401 | } |
David Howells | 69df79a | 2023-05-22 14:49:50 +0100 | [diff] [blame] | 402 | EXPORT_SYMBOL(copy_splice_read); |
David Howells | 33b3b04 | 2023-02-07 10:45:40 +0000 | [diff] [blame] | 403 | |
Al Viro | 241699c | 2016-09-22 16:33:12 -0400 | [diff] [blame] | 404 | const struct pipe_buf_operations default_pipe_buf_ops = { |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 405 | .release = generic_pipe_buf_release, |
| 406 | .try_steal = generic_pipe_buf_try_steal, |
| 407 | .get = generic_pipe_buf_get, |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 408 | }; |
| 409 | |
Miklos Szeredi | 28a625c | 2014-01-22 19:36:57 +0100 | [diff] [blame] | 410 | /* Pipe buffer operations for a socket and similar. */ |
| 411 | const struct pipe_buf_operations nosteal_pipe_buf_ops = { |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 412 | .release = generic_pipe_buf_release, |
| 413 | .get = generic_pipe_buf_get, |
Miklos Szeredi | 28a625c | 2014-01-22 19:36:57 +0100 | [diff] [blame] | 414 | }; |
| 415 | EXPORT_SYMBOL(nosteal_pipe_buf_ops); |
| 416 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 417 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
| 418 | { |
| 419 | smp_mb(); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 420 | if (waitqueue_active(&pipe->wr_wait)) |
| 421 | wake_up_interruptible(&pipe->wr_wait); |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 422 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
| 423 | } |
| 424 | |
| 425 | /** |
| 426 | * splice_from_pipe_feed - feed available data from a pipe to a file |
| 427 | * @pipe: pipe to splice from |
| 428 | * @sd: information to @actor |
| 429 | * @actor: handler that splices the data |
| 430 | * |
| 431 | * Description: |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 432 | * This function loops over the pipe and calls @actor to do the |
| 433 | * actual moving of a single struct pipe_buffer to the desired |
| 434 | * destination. It returns when there's no more buffers left in |
| 435 | * the pipe or if the requested number of bytes (@sd->total_len) |
| 436 | * have been copied. It returns a positive number (one) if the |
| 437 | * pipe needs to be filled with more data, zero if the required |
| 438 | * number of bytes have been copied and -errno on error. |
| 439 | * |
| 440 | * This, together with splice_from_pipe_{begin,end,next}, may be |
| 441 | * used to implement the functionality of __splice_from_pipe() when |
| 442 | * locking is required around copying the pipe buffers to the |
| 443 | * destination. |
| 444 | */ |
Al Viro | 96f9bc8 | 2014-04-05 04:35:49 -0400 | [diff] [blame] | 445 | static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 446 | splice_actor *actor) |
| 447 | { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 448 | unsigned int head = pipe->head; |
| 449 | unsigned int tail = pipe->tail; |
| 450 | unsigned int mask = pipe->ring_size - 1; |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 451 | int ret; |
| 452 | |
Linus Torvalds | ec05759 | 2019-12-06 12:40:35 -0800 | [diff] [blame] | 453 | while (!pipe_empty(head, tail)) { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 454 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 455 | |
| 456 | sd->len = buf->len; |
| 457 | if (sd->len > sd->total_len) |
| 458 | sd->len = sd->total_len; |
| 459 | |
Miklos Szeredi | fba597d | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 460 | ret = pipe_buf_confirm(pipe, buf); |
MichaĆ MirosĆaw | a8adbe3 | 2010-12-17 08:56:44 +0100 | [diff] [blame] | 461 | if (unlikely(ret)) { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 462 | if (ret == -ENODATA) |
| 463 | ret = 0; |
| 464 | return ret; |
| 465 | } |
MichaĆ MirosĆaw | a8adbe3 | 2010-12-17 08:56:44 +0100 | [diff] [blame] | 466 | |
| 467 | ret = actor(pipe, buf, sd); |
| 468 | if (ret <= 0) |
| 469 | return ret; |
| 470 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 471 | buf->offset += ret; |
| 472 | buf->len -= ret; |
| 473 | |
| 474 | sd->num_spliced += ret; |
| 475 | sd->len -= ret; |
| 476 | sd->pos += ret; |
| 477 | sd->total_len -= ret; |
| 478 | |
| 479 | if (!buf->len) { |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 480 | pipe_buf_release(pipe, buf); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 481 | tail++; |
| 482 | pipe->tail = tail; |
Al Viro | 6447a3c | 2013-03-21 11:01:38 -0400 | [diff] [blame] | 483 | if (pipe->files) |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 484 | sd->need_wakeup = true; |
| 485 | } |
| 486 | |
| 487 | if (!sd->total_len) |
| 488 | return 0; |
| 489 | } |
| 490 | |
| 491 | return 1; |
| 492 | } |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 493 | |
Linus Torvalds | d1a819a | 2020-10-05 11:26:27 -0700 | [diff] [blame] | 494 | /* We know we have a pipe buffer, but maybe it's empty? */ |
| 495 | static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) |
| 496 | { |
| 497 | unsigned int tail = pipe->tail; |
| 498 | unsigned int mask = pipe->ring_size - 1; |
| 499 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 500 | |
| 501 | if (unlikely(!buf->len)) { |
| 502 | pipe_buf_release(pipe, buf); |
| 503 | pipe->tail = tail+1; |
| 504 | return true; |
| 505 | } |
| 506 | |
| 507 | return false; |
| 508 | } |
| 509 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 510 | /** |
| 511 | * splice_from_pipe_next - wait for some data to splice from |
| 512 | * @pipe: pipe to splice from |
| 513 | * @sd: information about the splice operation |
| 514 | * |
| 515 | * Description: |
| 516 | * This function will wait for some data and return a positive |
| 517 | * value (one) if pipe buffers are available. It will return zero |
| 518 | * or -errno if no more data needs to be spliced. |
| 519 | */ |
Al Viro | 96f9bc8 | 2014-04-05 04:35:49 -0400 | [diff] [blame] | 520 | static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 521 | { |
Jan Kara | c725bfc | 2015-11-23 13:09:50 +0100 | [diff] [blame] | 522 | /* |
| 523 | * Check for signal early to make process killable when there are |
| 524 | * always buffers available |
| 525 | */ |
| 526 | if (signal_pending(current)) |
| 527 | return -ERESTARTSYS; |
| 528 | |
Linus Torvalds | d1a819a | 2020-10-05 11:26:27 -0700 | [diff] [blame] | 529 | repeat: |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 530 | while (pipe_empty(pipe->head, pipe->tail)) { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 531 | if (!pipe->writers) |
| 532 | return 0; |
| 533 | |
Linus Torvalds | a28c8b9 | 2019-12-07 13:21:01 -0800 | [diff] [blame] | 534 | if (sd->num_spliced) |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 535 | return 0; |
| 536 | |
| 537 | if (sd->flags & SPLICE_F_NONBLOCK) |
| 538 | return -EAGAIN; |
| 539 | |
| 540 | if (signal_pending(current)) |
| 541 | return -ERESTARTSYS; |
| 542 | |
| 543 | if (sd->need_wakeup) { |
| 544 | wakeup_pipe_writers(pipe); |
| 545 | sd->need_wakeup = false; |
| 546 | } |
| 547 | |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 548 | pipe_wait_readable(pipe); |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 549 | } |
| 550 | |
Linus Torvalds | d1a819a | 2020-10-05 11:26:27 -0700 | [diff] [blame] | 551 | if (eat_empty_buffer(pipe)) |
| 552 | goto repeat; |
| 553 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 554 | return 1; |
| 555 | } |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 556 | |
| 557 | /** |
| 558 | * splice_from_pipe_begin - start splicing from pipe |
Randy Dunlap | b80901b | 2009-04-16 19:09:55 -0700 | [diff] [blame] | 559 | * @sd: information about the splice operation |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 560 | * |
| 561 | * Description: |
| 562 | * This function should be called before a loop containing |
| 563 | * splice_from_pipe_next() and splice_from_pipe_feed() to |
| 564 | * initialize the necessary fields of @sd. |
| 565 | */ |
Al Viro | 96f9bc8 | 2014-04-05 04:35:49 -0400 | [diff] [blame] | 566 | static void splice_from_pipe_begin(struct splice_desc *sd) |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 567 | { |
| 568 | sd->num_spliced = 0; |
| 569 | sd->need_wakeup = false; |
| 570 | } |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 571 | |
| 572 | /** |
| 573 | * splice_from_pipe_end - finish splicing from pipe |
| 574 | * @pipe: pipe to splice from |
| 575 | * @sd: information about the splice operation |
| 576 | * |
| 577 | * Description: |
| 578 | * This function will wake up pipe writers if necessary. It should |
| 579 | * be called after a loop containing splice_from_pipe_next() and |
| 580 | * splice_from_pipe_feed(). |
| 581 | */ |
Al Viro | 96f9bc8 | 2014-04-05 04:35:49 -0400 | [diff] [blame] | 582 | static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 583 | { |
| 584 | if (sd->need_wakeup) |
| 585 | wakeup_pipe_writers(pipe); |
| 586 | } |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 587 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 588 | /** |
| 589 | * __splice_from_pipe - splice data from a pipe to given actor |
| 590 | * @pipe: pipe to splice from |
| 591 | * @sd: information to @actor |
| 592 | * @actor: handler that splices the data |
| 593 | * |
| 594 | * Description: |
| 595 | * This function does little more than loop over the pipe and call |
| 596 | * @actor to do the actual moving of a single struct pipe_buffer to |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 597 | * the desired destination. See pipe_to_file, pipe_to_sendmsg, or |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 598 | * pipe_to_user. |
| 599 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 600 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 601 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 602 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 603 | { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 604 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 605 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 606 | splice_from_pipe_begin(sd); |
| 607 | do { |
Jan Kara | c2489e0 | 2015-11-23 13:09:51 +0100 | [diff] [blame] | 608 | cond_resched(); |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 609 | ret = splice_from_pipe_next(pipe, sd); |
| 610 | if (ret > 0) |
| 611 | ret = splice_from_pipe_feed(pipe, sd, actor); |
| 612 | } while (ret > 0); |
| 613 | splice_from_pipe_end(pipe, sd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 614 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 615 | return sd->num_spliced ? sd->num_spliced : ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 616 | } |
Mark Fasheh | 40bee44e | 2007-03-21 13:11:02 +0100 | [diff] [blame] | 617 | EXPORT_SYMBOL(__splice_from_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 618 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 619 | /** |
| 620 | * splice_from_pipe - splice data from a pipe to a file |
| 621 | * @pipe: pipe to splice from |
| 622 | * @out: file to splice to |
| 623 | * @ppos: position in @out |
| 624 | * @len: how many bytes to splice |
| 625 | * @flags: splice modifier flags |
| 626 | * @actor: handler that splices the data |
| 627 | * |
| 628 | * Description: |
Miklos Szeredi | 2933970 | 2009-04-14 19:48:37 +0200 | [diff] [blame] | 629 | * See __splice_from_pipe. This function locks the pipe inode, |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 630 | * otherwise it's identical to __splice_from_pipe(). |
| 631 | * |
| 632 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 633 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 634 | loff_t *ppos, size_t len, unsigned int flags, |
| 635 | splice_actor *actor) |
| 636 | { |
| 637 | ssize_t ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 638 | struct splice_desc sd = { |
| 639 | .total_len = len, |
| 640 | .flags = flags, |
| 641 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 642 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 643 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 644 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 645 | pipe_lock(pipe); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 646 | ret = __splice_from_pipe(pipe, &sd, actor); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 647 | pipe_unlock(pipe); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 648 | |
| 649 | return ret; |
| 650 | } |
| 651 | |
| 652 | /** |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 653 | * iter_file_splice_write - splice data from a pipe to a file |
| 654 | * @pipe: pipe info |
| 655 | * @out: file to write to |
| 656 | * @ppos: position in @out |
| 657 | * @len: number of bytes to splice |
| 658 | * @flags: splice modifier flags |
| 659 | * |
| 660 | * Description: |
| 661 | * Will either move or copy pages (determined by @flags options) from |
| 662 | * the given pipe inode to the given file. |
| 663 | * This one is ->write_iter-based. |
| 664 | * |
| 665 | */ |
| 666 | ssize_t |
| 667 | iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
| 668 | loff_t *ppos, size_t len, unsigned int flags) |
| 669 | { |
| 670 | struct splice_desc sd = { |
| 671 | .total_len = len, |
| 672 | .flags = flags, |
| 673 | .pos = *ppos, |
| 674 | .u.file = out, |
| 675 | }; |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 676 | int nbufs = pipe->max_usage; |
Amir Goldstein | d53471ba6f | 2023-11-23 18:51:44 +0100 | [diff] [blame] | 677 | struct bio_vec *array; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 678 | ssize_t ret; |
| 679 | |
Amir Goldstein | d53471ba6f | 2023-11-23 18:51:44 +0100 | [diff] [blame] | 680 | if (!out->f_op->write_iter) |
| 681 | return -EINVAL; |
| 682 | |
| 683 | array = kcalloc(nbufs, sizeof(struct bio_vec), GFP_KERNEL); |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 684 | if (unlikely(!array)) |
| 685 | return -ENOMEM; |
| 686 | |
| 687 | pipe_lock(pipe); |
| 688 | |
| 689 | splice_from_pipe_begin(&sd); |
| 690 | while (sd.total_len) { |
Amir Goldstein | d53471ba6f | 2023-11-23 18:51:44 +0100 | [diff] [blame] | 691 | struct kiocb kiocb; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 692 | struct iov_iter from; |
Linus Torvalds | ec05759 | 2019-12-06 12:40:35 -0800 | [diff] [blame] | 693 | unsigned int head, tail, mask; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 694 | size_t left; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 695 | int n; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 696 | |
| 697 | ret = splice_from_pipe_next(pipe, &sd); |
| 698 | if (ret <= 0) |
| 699 | break; |
| 700 | |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 701 | if (unlikely(nbufs < pipe->max_usage)) { |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 702 | kfree(array); |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 703 | nbufs = pipe->max_usage; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 704 | array = kcalloc(nbufs, sizeof(struct bio_vec), |
| 705 | GFP_KERNEL); |
| 706 | if (!array) { |
| 707 | ret = -ENOMEM; |
| 708 | break; |
| 709 | } |
| 710 | } |
| 711 | |
Linus Torvalds | ec05759 | 2019-12-06 12:40:35 -0800 | [diff] [blame] | 712 | head = pipe->head; |
| 713 | tail = pipe->tail; |
| 714 | mask = pipe->ring_size - 1; |
| 715 | |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 716 | /* build the vector */ |
| 717 | left = sd.total_len; |
Pavel Begunkov | 0f1d344 | 2021-01-09 16:02:57 +0000 | [diff] [blame] | 718 | for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 719 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 720 | size_t this_len = buf->len; |
| 721 | |
Pavel Begunkov | 0f1d344 | 2021-01-09 16:02:57 +0000 | [diff] [blame] | 722 | /* zero-length bvecs are not supported, skip them */ |
| 723 | if (!this_len) |
| 724 | continue; |
| 725 | this_len = min(this_len, left); |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 726 | |
Miklos Szeredi | fba597d | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 727 | ret = pipe_buf_confirm(pipe, buf); |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 728 | if (unlikely(ret)) { |
| 729 | if (ret == -ENODATA) |
| 730 | ret = 0; |
| 731 | goto done; |
| 732 | } |
| 733 | |
Christoph Hellwig | 664e407 | 2023-02-03 16:06:28 +0100 | [diff] [blame] | 734 | bvec_set_page(&array[n], buf->page, this_len, |
| 735 | buf->offset); |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 736 | left -= this_len; |
Pavel Begunkov | 0f1d344 | 2021-01-09 16:02:57 +0000 | [diff] [blame] | 737 | n++; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 738 | } |
| 739 | |
Al Viro | de4eda9 | 2022-09-15 20:25:47 -0400 | [diff] [blame] | 740 | iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); |
Amir Goldstein | d53471ba6f | 2023-11-23 18:51:44 +0100 | [diff] [blame] | 741 | init_sync_kiocb(&kiocb, out); |
| 742 | kiocb.ki_pos = sd.pos; |
Miklos Szeredi | 7c98f7c | 2023-08-28 17:13:18 +0200 | [diff] [blame] | 743 | ret = out->f_op->write_iter(&kiocb, &from); |
Amir Goldstein | d53471ba6f | 2023-11-23 18:51:44 +0100 | [diff] [blame] | 744 | sd.pos = kiocb.ki_pos; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 745 | if (ret <= 0) |
| 746 | break; |
| 747 | |
| 748 | sd.num_spliced += ret; |
| 749 | sd.total_len -= ret; |
Christoph Hellwig | dbe4e19 | 2015-01-25 21:11:59 +0100 | [diff] [blame] | 750 | *ppos = sd.pos; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 751 | |
| 752 | /* dismiss the fully eaten buffers, adjust the partial one */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 753 | tail = pipe->tail; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 754 | while (ret) { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 755 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 756 | if (ret >= buf->len) { |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 757 | ret -= buf->len; |
| 758 | buf->len = 0; |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 759 | pipe_buf_release(pipe, buf); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 760 | tail++; |
| 761 | pipe->tail = tail; |
Al Viro | 8d02076 | 2014-04-05 04:27:08 -0400 | [diff] [blame] | 762 | if (pipe->files) |
| 763 | sd.need_wakeup = true; |
| 764 | } else { |
| 765 | buf->offset += ret; |
| 766 | buf->len -= ret; |
| 767 | ret = 0; |
| 768 | } |
| 769 | } |
| 770 | } |
| 771 | done: |
| 772 | kfree(array); |
| 773 | splice_from_pipe_end(pipe, &sd); |
| 774 | |
| 775 | pipe_unlock(pipe); |
| 776 | |
| 777 | if (sd.num_spliced) |
| 778 | ret = sd.num_spliced; |
| 779 | |
| 780 | return ret; |
| 781 | } |
| 782 | |
| 783 | EXPORT_SYMBOL(iter_file_splice_write); |
| 784 | |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 785 | #ifdef CONFIG_NET |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 786 | /** |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 787 | * splice_to_socket - splice data from a pipe to a socket |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 788 | * @pipe: pipe to splice from |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 789 | * @out: socket to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 790 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 791 | * @len: number of bytes to splice |
| 792 | * @flags: splice modifier flags |
| 793 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 794 | * Description: |
| 795 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 796 | * is involved. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 797 | * |
| 798 | */ |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 799 | ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, |
| 800 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 801 | { |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 802 | struct socket *sock = sock_from_file(out); |
| 803 | struct bio_vec bvec[16]; |
| 804 | struct msghdr msg = {}; |
| 805 | ssize_t ret = 0; |
| 806 | size_t spliced = 0; |
| 807 | bool need_wakeup = false; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 808 | |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 809 | pipe_lock(pipe); |
| 810 | |
| 811 | while (len > 0) { |
| 812 | unsigned int head, tail, mask, bc = 0; |
| 813 | size_t remain = len; |
| 814 | |
| 815 | /* |
| 816 | * Check for signal early to make process killable when there |
| 817 | * are always buffers available |
| 818 | */ |
| 819 | ret = -ERESTARTSYS; |
| 820 | if (signal_pending(current)) |
| 821 | break; |
| 822 | |
| 823 | while (pipe_empty(pipe->head, pipe->tail)) { |
| 824 | ret = 0; |
| 825 | if (!pipe->writers) |
| 826 | goto out; |
| 827 | |
| 828 | if (spliced) |
| 829 | goto out; |
| 830 | |
| 831 | ret = -EAGAIN; |
| 832 | if (flags & SPLICE_F_NONBLOCK) |
| 833 | goto out; |
| 834 | |
| 835 | ret = -ERESTARTSYS; |
| 836 | if (signal_pending(current)) |
| 837 | goto out; |
| 838 | |
| 839 | if (need_wakeup) { |
| 840 | wakeup_pipe_writers(pipe); |
| 841 | need_wakeup = false; |
| 842 | } |
| 843 | |
| 844 | pipe_wait_readable(pipe); |
| 845 | } |
| 846 | |
| 847 | head = pipe->head; |
| 848 | tail = pipe->tail; |
| 849 | mask = pipe->ring_size - 1; |
| 850 | |
| 851 | while (!pipe_empty(head, tail)) { |
| 852 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 853 | size_t seg; |
| 854 | |
| 855 | if (!buf->len) { |
| 856 | tail++; |
| 857 | continue; |
| 858 | } |
| 859 | |
| 860 | seg = min_t(size_t, remain, buf->len); |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 861 | |
| 862 | ret = pipe_buf_confirm(pipe, buf); |
| 863 | if (unlikely(ret)) { |
| 864 | if (ret == -ENODATA) |
| 865 | ret = 0; |
| 866 | break; |
| 867 | } |
| 868 | |
| 869 | bvec_set_page(&bvec[bc++], buf->page, seg, buf->offset); |
| 870 | remain -= seg; |
David Howells | ca2d49f | 2023-06-14 11:09:48 +0100 | [diff] [blame] | 871 | if (remain == 0 || bc >= ARRAY_SIZE(bvec)) |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 872 | break; |
David Howells | ca2d49f | 2023-06-14 11:09:48 +0100 | [diff] [blame] | 873 | tail++; |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 874 | } |
| 875 | |
| 876 | if (!bc) |
| 877 | break; |
| 878 | |
| 879 | msg.msg_flags = MSG_SPLICE_PAGES; |
| 880 | if (flags & SPLICE_F_MORE) |
| 881 | msg.msg_flags |= MSG_MORE; |
| 882 | if (remain && pipe_occupancy(pipe->head, tail) > 0) |
| 883 | msg.msg_flags |= MSG_MORE; |
Jan Stancek | 0f0fa27 | 2023-07-24 19:39:04 +0200 | [diff] [blame] | 884 | if (out->f_flags & O_NONBLOCK) |
| 885 | msg.msg_flags |= MSG_DONTWAIT; |
David Howells | 2dc334f | 2023-06-07 19:19:09 +0100 | [diff] [blame] | 886 | |
| 887 | iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, bvec, bc, |
| 888 | len - remain); |
| 889 | ret = sock_sendmsg(sock, &msg); |
| 890 | if (ret <= 0) |
| 891 | break; |
| 892 | |
| 893 | spliced += ret; |
| 894 | len -= ret; |
| 895 | tail = pipe->tail; |
| 896 | while (ret > 0) { |
| 897 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 898 | size_t seg = min_t(size_t, ret, buf->len); |
| 899 | |
| 900 | buf->offset += seg; |
| 901 | buf->len -= seg; |
| 902 | ret -= seg; |
| 903 | |
| 904 | if (!buf->len) { |
| 905 | pipe_buf_release(pipe, buf); |
| 906 | tail++; |
| 907 | } |
| 908 | } |
| 909 | |
| 910 | if (tail != pipe->tail) { |
| 911 | pipe->tail = tail; |
| 912 | if (pipe->files) |
| 913 | need_wakeup = true; |
| 914 | } |
| 915 | } |
| 916 | |
| 917 | out: |
| 918 | pipe_unlock(pipe); |
| 919 | if (need_wakeup) |
| 920 | wakeup_pipe_writers(pipe); |
| 921 | return spliced ?: ret; |
| 922 | } |
| 923 | #endif |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 924 | |
Christoph Hellwig | 36e2c74 | 2020-09-03 16:22:34 +0200 | [diff] [blame] | 925 | static int warn_unsupported(struct file *file, const char *op) |
| 926 | { |
| 927 | pr_debug_ratelimited( |
| 928 | "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", |
| 929 | op, file, current->pid, current->comm); |
| 930 | return -EINVAL; |
| 931 | } |
| 932 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 933 | /* |
| 934 | * Attempt to initiate a splice from pipe to file. |
| 935 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 936 | static ssize_t do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
| 937 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 938 | { |
Christoph Hellwig | 36e2c74 | 2020-09-03 16:22:34 +0200 | [diff] [blame] | 939 | if (unlikely(!out->f_op->splice_write)) |
| 940 | return warn_unsupported(out, "write"); |
| 941 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 942 | } |
| 943 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 944 | /* |
David Howells | 2bfc668 | 2023-06-07 19:19:10 +0100 | [diff] [blame] | 945 | * Indicate to the caller that there was a premature EOF when reading from the |
| 946 | * source and the caller didn't indicate they would be sending more data after |
| 947 | * this. |
| 948 | */ |
| 949 | static void do_splice_eof(struct splice_desc *sd) |
| 950 | { |
| 951 | if (sd->splice_eof) |
| 952 | sd->splice_eof(sd); |
| 953 | } |
| 954 | |
Amir Goldstein | feebea7 | 2023-11-22 14:27:02 +0200 | [diff] [blame] | 955 | /* |
| 956 | * Callers already called rw_verify_area() on the entire range. |
| 957 | * No need to call it for sub ranges. |
| 958 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 959 | static ssize_t do_splice_read(struct file *in, loff_t *ppos, |
| 960 | struct pipe_inode_info *pipe, size_t len, |
| 961 | unsigned int flags) |
Amir Goldstein | feebea7 | 2023-11-22 14:27:02 +0200 | [diff] [blame] | 962 | { |
| 963 | unsigned int p_space; |
| 964 | |
| 965 | if (unlikely(!(in->f_mode & FMODE_READ))) |
| 966 | return -EBADF; |
| 967 | if (!len) |
| 968 | return 0; |
| 969 | |
| 970 | /* Don't try to read more the pipe has space for. */ |
| 971 | p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); |
| 972 | len = min_t(size_t, len, p_space << PAGE_SHIFT); |
| 973 | |
| 974 | if (unlikely(len > MAX_RW_COUNT)) |
| 975 | len = MAX_RW_COUNT; |
| 976 | |
| 977 | if (unlikely(!in->f_op->splice_read)) |
| 978 | return warn_unsupported(in, "read"); |
| 979 | /* |
| 980 | * O_DIRECT and DAX don't deal with the pagecache, so we allocate a |
| 981 | * buffer, copy into it and splice that into the pipe. |
| 982 | */ |
| 983 | if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host)) |
| 984 | return copy_splice_read(in, ppos, pipe, len, flags); |
| 985 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
| 986 | } |
| 987 | |
David Howells | 6a3f30b | 2023-05-22 14:49:52 +0100 | [diff] [blame] | 988 | /** |
| 989 | * vfs_splice_read - Read data from a file and splice it into a pipe |
| 990 | * @in: File to splice from |
| 991 | * @ppos: Input file offset |
| 992 | * @pipe: Pipe to splice to |
| 993 | * @len: Number of bytes to splice |
| 994 | * @flags: Splice modifier flags (SPLICE_F_*) |
| 995 | * |
| 996 | * Splice the requested amount of data from the input file to the pipe. This |
| 997 | * is synchronous as the caller must hold the pipe lock across the entire |
| 998 | * operation. |
| 999 | * |
| 1000 | * If successful, it returns the amount of data spliced, 0 if it hit the EOF or |
| 1001 | * a hole and a negative error code otherwise. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1002 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1003 | ssize_t vfs_splice_read(struct file *in, loff_t *ppos, |
| 1004 | struct pipe_inode_info *pipe, size_t len, |
| 1005 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1006 | { |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1007 | ssize_t ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1008 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1009 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1010 | if (unlikely(ret < 0)) |
| 1011 | return ret; |
| 1012 | |
Amir Goldstein | feebea7 | 2023-11-22 14:27:02 +0200 | [diff] [blame] | 1013 | return do_splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1014 | } |
David Howells | 6a3f30b | 2023-05-22 14:49:52 +0100 | [diff] [blame] | 1015 | EXPORT_SYMBOL_GPL(vfs_splice_read); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1016 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1017 | /** |
| 1018 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 1019 | * @in: file to splice from |
| 1020 | * @sd: actor information on where to splice to |
| 1021 | * @actor: handles the data splicing |
| 1022 | * |
| 1023 | * Description: |
| 1024 | * This is a special case helper to splice directly between two |
| 1025 | * points, without requiring an explicit pipe. Internally an allocated |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 1026 | * pipe is cached in the process, and reused during the lifetime of |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1027 | * that process. |
| 1028 | * |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1029 | */ |
| 1030 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 1031 | splice_direct_actor *actor) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1032 | { |
| 1033 | struct pipe_inode_info *pipe; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1034 | ssize_t ret, bytes; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1035 | size_t len; |
Christophe Leroy | 0ff28d9 | 2015-05-06 17:26:47 +0200 | [diff] [blame] | 1036 | int i, flags, more; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1037 | |
| 1038 | /* |
Jason A. Donenfeld | 97ef77c | 2022-06-29 15:06:58 +0200 | [diff] [blame] | 1039 | * We require the input to be seekable, as we don't want to randomly |
| 1040 | * drop data for eg socket -> socket splicing. Use the piped splicing |
| 1041 | * for that! |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1042 | */ |
Jason A. Donenfeld | 97ef77c | 2022-06-29 15:06:58 +0200 | [diff] [blame] | 1043 | if (unlikely(!(in->f_mode & FMODE_LSEEK))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1044 | return -EINVAL; |
| 1045 | |
| 1046 | /* |
| 1047 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 1048 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 1049 | */ |
| 1050 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1051 | if (unlikely(!pipe)) { |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame] | 1052 | pipe = alloc_pipe_info(); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1053 | if (!pipe) |
| 1054 | return -ENOMEM; |
| 1055 | |
| 1056 | /* |
| 1057 | * We don't have an immediate reader, but we'll read the stuff |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1058 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1059 | * PIPE_READERS appropriately. |
| 1060 | */ |
| 1061 | pipe->readers = 1; |
| 1062 | |
| 1063 | current->splice_pipe = pipe; |
| 1064 | } |
| 1065 | |
| 1066 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 1067 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1068 | */ |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1069 | bytes = 0; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1070 | len = sd->total_len; |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1071 | |
| 1072 | /* Don't block on output, we have to drain the direct pipe. */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1073 | flags = sd->flags; |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1074 | sd->flags &= ~SPLICE_F_NONBLOCK; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1075 | |
| 1076 | /* |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1077 | * We signal MORE until we've read sufficient data to fulfill the |
| 1078 | * request and we keep signalling it if the caller set it. |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1079 | */ |
Christophe Leroy | 0ff28d9 | 2015-05-06 17:26:47 +0200 | [diff] [blame] | 1080 | more = sd->flags & SPLICE_F_MORE; |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1081 | sd->flags |= SPLICE_F_MORE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1082 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1083 | WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); |
Darrick J. Wong | 1761444 | 2018-11-30 10:37:49 -0800 | [diff] [blame] | 1084 | |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1085 | while (len) { |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1086 | size_t read_len; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1087 | loff_t pos = sd->pos, prev_pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1088 | |
Amir Goldstein | feebea7 | 2023-11-22 14:27:02 +0200 | [diff] [blame] | 1089 | ret = do_splice_read(in, &pos, pipe, len, flags); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1090 | if (unlikely(ret <= 0)) |
David Howells | 2bfc668 | 2023-06-07 19:19:10 +0100 | [diff] [blame] | 1091 | goto read_failure; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1092 | |
| 1093 | read_len = ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1094 | sd->total_len = read_len; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1095 | |
| 1096 | /* |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1097 | * If we now have sufficient data to fulfill the request then |
| 1098 | * we clear SPLICE_F_MORE if it was not set initially. |
Christophe Leroy | 0ff28d9 | 2015-05-06 17:26:47 +0200 | [diff] [blame] | 1099 | */ |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1100 | if (read_len >= len && !more) |
Christophe Leroy | 0ff28d9 | 2015-05-06 17:26:47 +0200 | [diff] [blame] | 1101 | sd->flags &= ~SPLICE_F_MORE; |
David Howells | 219d920 | 2023-06-07 19:19:16 +0100 | [diff] [blame] | 1102 | |
Christophe Leroy | 0ff28d9 | 2015-05-06 17:26:47 +0200 | [diff] [blame] | 1103 | /* |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1104 | * NOTE: nonblocking mode only applies to the input. We |
| 1105 | * must not do the output in nonblocking mode as then we |
| 1106 | * could get stuck data in the internal pipe: |
| 1107 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1108 | ret = actor(pipe, sd); |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1109 | if (unlikely(ret <= 0)) { |
| 1110 | sd->pos = prev_pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1111 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1112 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1113 | |
| 1114 | bytes += ret; |
| 1115 | len -= ret; |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1116 | sd->pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1117 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1118 | if (ret < read_len) { |
| 1119 | sd->pos = prev_pos + ret; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1120 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1121 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1122 | } |
| 1123 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1124 | done: |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1125 | pipe->tail = pipe->head = 0; |
Jens Axboe | 8084870 | 2008-01-30 12:24:48 +0100 | [diff] [blame] | 1126 | file_accessed(in); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1127 | return bytes; |
| 1128 | |
David Howells | 2bfc668 | 2023-06-07 19:19:10 +0100 | [diff] [blame] | 1129 | read_failure: |
| 1130 | /* |
| 1131 | * If the user did *not* set SPLICE_F_MORE *and* we didn't hit that |
| 1132 | * "use all of len" case that cleared SPLICE_F_MORE, *and* we did a |
| 1133 | * "->splice_in()" that returned EOF (ie zero) *and* we have sent at |
| 1134 | * least 1 byte *then* we will also do the ->splice_eof() call. |
| 1135 | */ |
| 1136 | if (ret == 0 && !more && len > 0 && bytes) |
| 1137 | do_splice_eof(sd); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1138 | out_release: |
| 1139 | /* |
| 1140 | * If we did an incomplete transfer we must release |
| 1141 | * the pipe buffers in question: |
| 1142 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1143 | for (i = 0; i < pipe->ring_size; i++) { |
| 1144 | struct pipe_buffer *buf = &pipe->bufs[i]; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1145 | |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 1146 | if (buf->ops) |
| 1147 | pipe_buf_release(pipe, buf); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1148 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1149 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1150 | if (!bytes) |
| 1151 | bytes = ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1152 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1153 | goto done; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1154 | } |
| 1155 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1156 | |
| 1157 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1158 | struct splice_desc *sd) |
| 1159 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1160 | struct file *file = sd->u.file; |
Amir Goldstein | da40448 | 2023-11-30 16:16:23 +0200 | [diff] [blame] | 1161 | long ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1162 | |
Amir Goldstein | da40448 | 2023-11-30 16:16:23 +0200 | [diff] [blame] | 1163 | file_start_write(file); |
| 1164 | ret = do_splice_from(pipe, file, sd->opos, sd->total_len, sd->flags); |
| 1165 | file_end_write(file); |
| 1166 | return ret; |
| 1167 | } |
| 1168 | |
| 1169 | static int splice_file_range_actor(struct pipe_inode_info *pipe, |
| 1170 | struct splice_desc *sd) |
| 1171 | { |
| 1172 | struct file *file = sd->u.file; |
| 1173 | |
| 1174 | return do_splice_from(pipe, file, sd->opos, sd->total_len, sd->flags); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1175 | } |
| 1176 | |
David Howells | 2bfc668 | 2023-06-07 19:19:10 +0100 | [diff] [blame] | 1177 | static void direct_file_splice_eof(struct splice_desc *sd) |
| 1178 | { |
| 1179 | struct file *file = sd->u.file; |
| 1180 | |
| 1181 | if (file->f_op->splice_eof) |
| 1182 | file->f_op->splice_eof(file); |
| 1183 | } |
| 1184 | |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1185 | static ssize_t do_splice_direct_actor(struct file *in, loff_t *ppos, |
| 1186 | struct file *out, loff_t *opos, |
| 1187 | size_t len, unsigned int flags, |
| 1188 | splice_direct_actor *actor) |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1189 | { |
| 1190 | struct splice_desc sd = { |
| 1191 | .len = len, |
| 1192 | .total_len = len, |
| 1193 | .flags = flags, |
| 1194 | .pos = *ppos, |
| 1195 | .u.file = out, |
| 1196 | .splice_eof = direct_file_splice_eof, |
| 1197 | .opos = opos, |
| 1198 | }; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1199 | ssize_t ret; |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1200 | |
| 1201 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
| 1202 | return -EBADF; |
| 1203 | |
| 1204 | if (unlikely(out->f_flags & O_APPEND)) |
| 1205 | return -EINVAL; |
| 1206 | |
| 1207 | ret = splice_direct_to_actor(in, &sd, actor); |
| 1208 | if (ret > 0) |
| 1209 | *ppos = sd.pos; |
| 1210 | |
| 1211 | return ret; |
| 1212 | } |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1213 | /** |
| 1214 | * do_splice_direct - splices data directly between two files |
| 1215 | * @in: file to splice from |
| 1216 | * @ppos: input file offset |
| 1217 | * @out: file to splice to |
Randy Dunlap | acdb37c | 2013-06-22 19:44:08 -0700 | [diff] [blame] | 1218 | * @opos: output file offset |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1219 | * @len: number of bytes to splice |
| 1220 | * @flags: splice modifier flags |
| 1221 | * |
| 1222 | * Description: |
| 1223 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1224 | * doing it in the application would incur an extra system call |
| 1225 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1226 | * can splice directly through a process-private pipe. |
| 1227 | * |
Amir Goldstein | 2a33e2d | 2023-11-22 14:27:01 +0200 | [diff] [blame] | 1228 | * Callers already called rw_verify_area() on the entire range. |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1229 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1230 | ssize_t do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1231 | loff_t *opos, size_t len, unsigned int flags) |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1232 | { |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1233 | return do_splice_direct_actor(in, ppos, out, opos, len, flags, |
| 1234 | direct_splice_actor); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1235 | } |
Miklos Szeredi | 1c11859 | 2014-10-24 00:14:35 +0200 | [diff] [blame] | 1236 | EXPORT_SYMBOL(do_splice_direct); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1237 | |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1238 | /** |
| 1239 | * splice_file_range - splices data between two files for copy_file_range() |
| 1240 | * @in: file to splice from |
| 1241 | * @ppos: input file offset |
| 1242 | * @out: file to splice to |
| 1243 | * @opos: output file offset |
| 1244 | * @len: number of bytes to splice |
| 1245 | * |
| 1246 | * Description: |
Amir Goldstein | 705bcfc | 2023-12-12 11:44:37 +0200 | [diff] [blame] | 1247 | * For use by ->copy_file_range() methods. |
Amir Goldstein | da40448 | 2023-11-30 16:16:23 +0200 | [diff] [blame] | 1248 | * Like do_splice_direct(), but vfs_copy_file_range() already holds |
| 1249 | * start_file_write() on @out file. |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1250 | * |
| 1251 | * Callers already called rw_verify_area() on the entire range. |
| 1252 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1253 | ssize_t splice_file_range(struct file *in, loff_t *ppos, struct file *out, |
| 1254 | loff_t *opos, size_t len) |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1255 | { |
| 1256 | lockdep_assert(file_write_started(out)); |
| 1257 | |
Amir Goldstein | 705bcfc | 2023-12-12 11:44:37 +0200 | [diff] [blame] | 1258 | return do_splice_direct_actor(in, ppos, out, opos, |
| 1259 | min_t(size_t, len, MAX_RW_COUNT), |
| 1260 | 0, splice_file_range_actor); |
Amir Goldstein | 488e8f6 | 2023-11-30 16:16:22 +0200 | [diff] [blame] | 1261 | } |
| 1262 | EXPORT_SYMBOL(splice_file_range); |
| 1263 | |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1264 | static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) |
| 1265 | { |
Linus Torvalds | 52bce91 | 2016-12-21 10:59:34 -0800 | [diff] [blame] | 1266 | for (;;) { |
| 1267 | if (unlikely(!pipe->readers)) { |
| 1268 | send_sig(SIGPIPE, current, 0); |
| 1269 | return -EPIPE; |
| 1270 | } |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1271 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
Linus Torvalds | 52bce91 | 2016-12-21 10:59:34 -0800 | [diff] [blame] | 1272 | return 0; |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1273 | if (flags & SPLICE_F_NONBLOCK) |
| 1274 | return -EAGAIN; |
| 1275 | if (signal_pending(current)) |
| 1276 | return -ERESTARTSYS; |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1277 | pipe_wait_writable(pipe); |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1278 | } |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1279 | } |
| 1280 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1281 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1282 | struct pipe_inode_info *opipe, |
| 1283 | size_t len, unsigned int flags); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1284 | |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1285 | ssize_t splice_file_to_pipe(struct file *in, |
| 1286 | struct pipe_inode_info *opipe, |
| 1287 | loff_t *offset, |
| 1288 | size_t len, unsigned int flags) |
Al Viro | faa97c4 | 2021-01-25 22:23:03 -0500 | [diff] [blame] | 1289 | { |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1290 | ssize_t ret; |
Al Viro | faa97c4 | 2021-01-25 22:23:03 -0500 | [diff] [blame] | 1291 | |
| 1292 | pipe_lock(opipe); |
| 1293 | ret = wait_for_space(opipe, flags); |
| 1294 | if (!ret) |
Amir Goldstein | b70d8e2 | 2023-11-22 14:27:03 +0200 | [diff] [blame] | 1295 | ret = do_splice_read(in, offset, opipe, len, flags); |
Al Viro | faa97c4 | 2021-01-25 22:23:03 -0500 | [diff] [blame] | 1296 | pipe_unlock(opipe); |
| 1297 | if (ret > 0) |
| 1298 | wakeup_pipe_readers(opipe); |
| 1299 | return ret; |
| 1300 | } |
| 1301 | |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1302 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1303 | * Determine where to splice to/from. |
| 1304 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1305 | ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out, |
| 1306 | loff_t *off_out, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1307 | { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1308 | struct pipe_inode_info *ipipe; |
| 1309 | struct pipe_inode_info *opipe; |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1310 | loff_t offset; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1311 | ssize_t ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1312 | |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 1313 | if (unlikely(!(in->f_mode & FMODE_READ) || |
| 1314 | !(out->f_mode & FMODE_WRITE))) |
| 1315 | return -EBADF; |
| 1316 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1317 | ipipe = get_pipe_info(in, true); |
| 1318 | opipe = get_pipe_info(out, true); |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1319 | |
| 1320 | if (ipipe && opipe) { |
| 1321 | if (off_in || off_out) |
| 1322 | return -ESPIPE; |
| 1323 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1324 | /* Splicing to self would be fun, but... */ |
| 1325 | if (ipipe == opipe) |
| 1326 | return -EINVAL; |
| 1327 | |
Slavomir Kaslev | ee5e001 | 2019-02-07 17:45:19 +0200 | [diff] [blame] | 1328 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
| 1329 | flags |= SPLICE_F_NONBLOCK; |
| 1330 | |
Ahelenia ZiemiaĆska | 12ee4b6 | 2023-07-03 16:42:13 +0200 | [diff] [blame] | 1331 | ret = splice_pipe_to_pipe(ipipe, opipe, len, flags); |
| 1332 | } else if (ipipe) { |
Ingo Molnar | 529565dc | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1333 | if (off_in) |
| 1334 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1335 | if (off_out) { |
Changli Gao | 19c9a49 | 2010-06-29 13:10:36 +0200 | [diff] [blame] | 1336 | if (!(out->f_mode & FMODE_PWRITE)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1337 | return -EINVAL; |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1338 | offset = *off_out; |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1339 | } else { |
| 1340 | offset = out->f_pos; |
| 1341 | } |
Ingo Molnar | 529565dc | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1342 | |
Al Viro | 18c67cb | 2013-06-19 15:41:54 +0400 | [diff] [blame] | 1343 | if (unlikely(out->f_flags & O_APPEND)) |
| 1344 | return -EINVAL; |
| 1345 | |
| 1346 | ret = rw_verify_area(WRITE, out, &offset, len); |
| 1347 | if (unlikely(ret < 0)) |
| 1348 | return ret; |
| 1349 | |
Slavomir Kaslev | ee5e001 | 2019-02-07 17:45:19 +0200 | [diff] [blame] | 1350 | if (in->f_flags & O_NONBLOCK) |
| 1351 | flags |= SPLICE_F_NONBLOCK; |
| 1352 | |
Al Viro | 500368f | 2013-05-23 20:07:11 -0400 | [diff] [blame] | 1353 | file_start_write(out); |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1354 | ret = do_splice_from(ipipe, out, &offset, len, flags); |
Al Viro | 500368f | 2013-05-23 20:07:11 -0400 | [diff] [blame] | 1355 | file_end_write(out); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1356 | |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1357 | if (!off_out) |
| 1358 | out->f_pos = offset; |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1359 | else |
| 1360 | *off_out = offset; |
Ahelenia ZiemiaĆska | 12ee4b6 | 2023-07-03 16:42:13 +0200 | [diff] [blame] | 1361 | } else if (opipe) { |
Ingo Molnar | 529565dc | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1362 | if (off_out) |
| 1363 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1364 | if (off_in) { |
Changli Gao | 19c9a49 | 2010-06-29 13:10:36 +0200 | [diff] [blame] | 1365 | if (!(in->f_mode & FMODE_PREAD)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1366 | return -EINVAL; |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1367 | offset = *off_in; |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1368 | } else { |
| 1369 | offset = in->f_pos; |
| 1370 | } |
Ingo Molnar | 529565dc | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1371 | |
Amir Goldstein | b70d8e2 | 2023-11-22 14:27:03 +0200 | [diff] [blame] | 1372 | ret = rw_verify_area(READ, in, &offset, len); |
| 1373 | if (unlikely(ret < 0)) |
| 1374 | return ret; |
| 1375 | |
Slavomir Kaslev | ee5e001 | 2019-02-07 17:45:19 +0200 | [diff] [blame] | 1376 | if (out->f_flags & O_NONBLOCK) |
| 1377 | flags |= SPLICE_F_NONBLOCK; |
| 1378 | |
Al Viro | faa97c4 | 2021-01-25 22:23:03 -0500 | [diff] [blame] | 1379 | ret = splice_file_to_pipe(in, opipe, &offset, len, flags); |
Chung-Chiang Cheng | 983652c | 2023-03-22 14:25:19 +0800 | [diff] [blame] | 1380 | |
Al Viro | 7995bd2 | 2013-06-20 18:58:36 +0400 | [diff] [blame] | 1381 | if (!off_in) |
| 1382 | in->f_pos = offset; |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1383 | else |
| 1384 | *off_in = offset; |
Ahelenia ZiemiaĆska | 12ee4b6 | 2023-07-03 16:42:13 +0200 | [diff] [blame] | 1385 | } else { |
| 1386 | ret = -EINVAL; |
Ingo Molnar | 529565dc | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1387 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1388 | |
Ahelenia ZiemiaĆska | 12ee4b6 | 2023-07-03 16:42:13 +0200 | [diff] [blame] | 1389 | if (ret > 0) { |
| 1390 | /* |
| 1391 | * Generate modify out before access in: |
| 1392 | * do_splice_from() may've already sent modify out, |
| 1393 | * and this ensures the events get merged. |
| 1394 | */ |
| 1395 | fsnotify_modify(out); |
| 1396 | fsnotify_access(in); |
| 1397 | } |
| 1398 | |
| 1399 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1400 | } |
| 1401 | |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1402 | static ssize_t __do_splice(struct file *in, loff_t __user *off_in, |
| 1403 | struct file *out, loff_t __user *off_out, |
| 1404 | size_t len, unsigned int flags) |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1405 | { |
| 1406 | struct pipe_inode_info *ipipe; |
| 1407 | struct pipe_inode_info *opipe; |
| 1408 | loff_t offset, *__off_in = NULL, *__off_out = NULL; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1409 | ssize_t ret; |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1410 | |
| 1411 | ipipe = get_pipe_info(in, true); |
| 1412 | opipe = get_pipe_info(out, true); |
| 1413 | |
Jens Axboe | 0f99fc5 | 2023-04-24 16:32:55 -0600 | [diff] [blame] | 1414 | if (ipipe) { |
| 1415 | if (off_in) |
| 1416 | return -ESPIPE; |
| 1417 | pipe_clear_nowait(in); |
| 1418 | } |
| 1419 | if (opipe) { |
| 1420 | if (off_out) |
| 1421 | return -ESPIPE; |
| 1422 | pipe_clear_nowait(out); |
| 1423 | } |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1424 | |
| 1425 | if (off_out) { |
| 1426 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
| 1427 | return -EFAULT; |
| 1428 | __off_out = &offset; |
| 1429 | } |
| 1430 | if (off_in) { |
| 1431 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
| 1432 | return -EFAULT; |
| 1433 | __off_in = &offset; |
| 1434 | } |
| 1435 | |
| 1436 | ret = do_splice(in, __off_in, out, __off_out, len, flags); |
| 1437 | if (ret < 0) |
| 1438 | return ret; |
| 1439 | |
| 1440 | if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) |
| 1441 | return -EFAULT; |
| 1442 | if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) |
| 1443 | return -EFAULT; |
| 1444 | |
| 1445 | return ret; |
| 1446 | } |
| 1447 | |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1448 | static ssize_t iter_to_pipe(struct iov_iter *from, |
| 1449 | struct pipe_inode_info *pipe, |
| 1450 | unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1451 | { |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1452 | struct pipe_buffer buf = { |
| 1453 | .ops = &user_page_pipe_buf_ops, |
| 1454 | .flags = flags |
| 1455 | }; |
| 1456 | size_t total = 0; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1457 | ssize_t ret = 0; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1458 | |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1459 | while (iov_iter_count(from)) { |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1460 | struct page *pages[16]; |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1461 | ssize_t left; |
Al Viro | db85a9e | 2016-09-17 20:25:06 -0400 | [diff] [blame] | 1462 | size_t start; |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1463 | int i, n; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1464 | |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1465 | left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); |
| 1466 | if (left <= 0) { |
| 1467 | ret = left; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1468 | break; |
| 1469 | } |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1470 | |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1471 | n = DIV_ROUND_UP(left + start, PAGE_SIZE); |
| 1472 | for (i = 0; i < n; i++) { |
| 1473 | int size = min_t(int, left, PAGE_SIZE - start); |
| 1474 | |
| 1475 | buf.page = pages[i]; |
| 1476 | buf.offset = start; |
| 1477 | buf.len = size; |
| 1478 | ret = add_to_pipe(pipe, &buf); |
| 1479 | if (unlikely(ret < 0)) { |
| 1480 | iov_iter_revert(from, left); |
| 1481 | // this one got dropped by add_to_pipe() |
| 1482 | while (++i < n) |
| 1483 | put_page(pages[i]); |
| 1484 | goto out; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1485 | } |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1486 | total += ret; |
| 1487 | left -= size; |
| 1488 | start = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1489 | } |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1490 | } |
Al Viro | 7d690c1 | 2022-06-09 11:07:52 -0400 | [diff] [blame] | 1491 | out: |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1492 | return total ? total : ret; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1493 | } |
| 1494 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1495 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1496 | struct splice_desc *sd) |
| 1497 | { |
Al Viro | 6130f53 | 2014-02-03 18:19:51 -0500 | [diff] [blame] | 1498 | int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); |
| 1499 | return n == sd->len ? n : -EFAULT; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1500 | } |
| 1501 | |
| 1502 | /* |
| 1503 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1504 | * as a simple copy of the pipes pages to the user iov. |
| 1505 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1506 | static ssize_t vmsplice_to_user(struct file *file, struct iov_iter *iter, |
| 1507 | unsigned int flags) |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1508 | { |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1509 | struct pipe_inode_info *pipe = get_pipe_info(file, true); |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1510 | struct splice_desc sd = { |
| 1511 | .total_len = iov_iter_count(iter), |
| 1512 | .flags = flags, |
| 1513 | .u.data = iter |
| 1514 | }; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1515 | ssize_t ret = 0; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1516 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1517 | if (!pipe) |
| 1518 | return -EBADF; |
| 1519 | |
Jens Axboe | 0f99fc5 | 2023-04-24 16:32:55 -0600 | [diff] [blame] | 1520 | pipe_clear_nowait(file); |
| 1521 | |
Al Viro | 345995f | 2015-03-21 19:17:55 -0400 | [diff] [blame] | 1522 | if (sd.total_len) { |
| 1523 | pipe_lock(pipe); |
| 1524 | ret = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1525 | pipe_unlock(pipe); |
| 1526 | } |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1527 | |
Ahelenia ZiemiaĆska | 7f0f1ea0 | 2023-07-03 16:42:17 +0200 | [diff] [blame] | 1528 | if (ret > 0) |
| 1529 | fsnotify_access(file); |
| 1530 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1531 | return ret; |
| 1532 | } |
| 1533 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1534 | /* |
| 1535 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1536 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1537 | * to file). In both cases the output is a pipe, naturally. |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1538 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1539 | static ssize_t vmsplice_to_pipe(struct file *file, struct iov_iter *iter, |
| 1540 | unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1541 | { |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1542 | struct pipe_inode_info *pipe; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1543 | ssize_t ret = 0; |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1544 | unsigned buf_flag = 0; |
| 1545 | |
| 1546 | if (flags & SPLICE_F_GIFT) |
| 1547 | buf_flag = PIPE_BUF_FLAG_GIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1548 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1549 | pipe = get_pipe_info(file, true); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1550 | if (!pipe) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1551 | return -EBADF; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1552 | |
Jens Axboe | 0f99fc5 | 2023-04-24 16:32:55 -0600 | [diff] [blame] | 1553 | pipe_clear_nowait(file); |
| 1554 | |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1555 | pipe_lock(pipe); |
| 1556 | ret = wait_for_space(pipe, flags); |
Al Viro | 79fddc4 | 2016-09-17 22:38:20 -0400 | [diff] [blame] | 1557 | if (!ret) |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1558 | ret = iter_to_pipe(iter, pipe, buf_flag); |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1559 | pipe_unlock(pipe); |
Ahelenia ZiemiaĆska | 7f0f1ea0 | 2023-07-03 16:42:17 +0200 | [diff] [blame] | 1560 | if (ret > 0) { |
Al Viro | 8924fef | 2016-09-17 20:44:45 -0400 | [diff] [blame] | 1561 | wakeup_pipe_readers(pipe); |
Ahelenia ZiemiaĆska | 7f0f1ea0 | 2023-07-03 16:42:17 +0200 | [diff] [blame] | 1562 | fsnotify_modify(file); |
| 1563 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1564 | return ret; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1565 | } |
| 1566 | |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1567 | static int vmsplice_type(struct fd f, int *type) |
| 1568 | { |
| 1569 | if (!f.file) |
| 1570 | return -EBADF; |
| 1571 | if (f.file->f_mode & FMODE_WRITE) { |
Al Viro | de4eda9 | 2022-09-15 20:25:47 -0400 | [diff] [blame] | 1572 | *type = ITER_SOURCE; |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1573 | } else if (f.file->f_mode & FMODE_READ) { |
Al Viro | de4eda9 | 2022-09-15 20:25:47 -0400 | [diff] [blame] | 1574 | *type = ITER_DEST; |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1575 | } else { |
| 1576 | fdput(f); |
| 1577 | return -EBADF; |
| 1578 | } |
| 1579 | return 0; |
| 1580 | } |
| 1581 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1582 | /* |
| 1583 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1584 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1585 | * operation that can be supported without any funky alignment restrictions |
| 1586 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1587 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1588 | * solutions for that: |
| 1589 | * |
| 1590 | * - memcpy() the data internally, at which point we might as well just |
| 1591 | * do a regular read() on the buffer anyway. |
| 1592 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1593 | * has restriction limitations on both ends of the pipe). |
| 1594 | * |
| 1595 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1596 | * |
| 1597 | */ |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1598 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, |
Dominik Brodowski | 30cfe4e | 2018-03-17 15:00:24 +0100 | [diff] [blame] | 1599 | unsigned long, nr_segs, unsigned int, flags) |
| 1600 | { |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1601 | struct iovec iovstack[UIO_FASTIOV]; |
| 1602 | struct iovec *iov = iovstack; |
| 1603 | struct iov_iter iter; |
Jens Axboe | 87e5e6d | 2019-05-14 16:02:22 -0600 | [diff] [blame] | 1604 | ssize_t error; |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1605 | struct fd f; |
| 1606 | int type; |
| 1607 | |
Christoph Hellwig | 598b3ce | 2020-09-25 06:51:44 +0200 | [diff] [blame] | 1608 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 1609 | return -EINVAL; |
| 1610 | |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1611 | f = fdget(fd); |
| 1612 | error = vmsplice_type(f, &type); |
| 1613 | if (error) |
| 1614 | return error; |
| 1615 | |
| 1616 | error = import_iovec(type, uiov, nr_segs, |
| 1617 | ARRAY_SIZE(iovstack), &iov, &iter); |
Christoph Hellwig | 598b3ce | 2020-09-25 06:51:44 +0200 | [diff] [blame] | 1618 | if (error < 0) |
| 1619 | goto out_fdput; |
| 1620 | |
| 1621 | if (!iov_iter_count(&iter)) |
| 1622 | error = 0; |
Al Viro | de4eda9 | 2022-09-15 20:25:47 -0400 | [diff] [blame] | 1623 | else if (type == ITER_SOURCE) |
Christoph Hellwig | 598b3ce | 2020-09-25 06:51:44 +0200 | [diff] [blame] | 1624 | error = vmsplice_to_pipe(f.file, &iter, flags); |
| 1625 | else |
| 1626 | error = vmsplice_to_user(f.file, &iter, flags); |
| 1627 | |
| 1628 | kfree(iov); |
| 1629 | out_fdput: |
Al Viro | 87a3002 | 2018-05-26 21:39:52 -0400 | [diff] [blame] | 1630 | fdput(f); |
| 1631 | return error; |
Dominik Brodowski | 30cfe4e | 2018-03-17 15:00:24 +0100 | [diff] [blame] | 1632 | } |
| 1633 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1634 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
| 1635 | int, fd_out, loff_t __user *, off_out, |
| 1636 | size_t, len, unsigned int, flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1637 | { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1638 | struct fd in, out; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1639 | ssize_t error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1640 | |
| 1641 | if (unlikely(!len)) |
| 1642 | return 0; |
| 1643 | |
Al Viro | 3d6ea29 | 2016-12-10 13:17:32 -0500 | [diff] [blame] | 1644 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 1645 | return -EINVAL; |
| 1646 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1647 | error = -EBADF; |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1648 | in = fdget(fd_in); |
| 1649 | if (in.file) { |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 1650 | out = fdget(fd_out); |
| 1651 | if (out.file) { |
Jens Axboe | ee6e00c | 2020-10-22 14:15:51 -0600 | [diff] [blame] | 1652 | error = __do_splice(in.file, off_in, out.file, off_out, |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1653 | len, flags); |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 1654 | fdput(out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1655 | } |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1656 | fdput(in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1657 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1658 | return error; |
| 1659 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1660 | |
| 1661 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1662 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1663 | * return an appropriate error. |
| 1664 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1665 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1666 | { |
| 1667 | int ret; |
| 1668 | |
| 1669 | /* |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1670 | * Check the pipe occupancy without the inode lock first. This function |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1671 | * is speculative anyways, so missing one is ok. |
| 1672 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1673 | if (!pipe_empty(pipe->head, pipe->tail)) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1674 | return 0; |
| 1675 | |
| 1676 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1677 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1678 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1679 | while (pipe_empty(pipe->head, pipe->tail)) { |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1680 | if (signal_pending(current)) { |
| 1681 | ret = -ERESTARTSYS; |
| 1682 | break; |
| 1683 | } |
| 1684 | if (!pipe->writers) |
| 1685 | break; |
Linus Torvalds | a28c8b9 | 2019-12-07 13:21:01 -0800 | [diff] [blame] | 1686 | if (flags & SPLICE_F_NONBLOCK) { |
| 1687 | ret = -EAGAIN; |
| 1688 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1689 | } |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1690 | pipe_wait_readable(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1691 | } |
| 1692 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1693 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1694 | return ret; |
| 1695 | } |
| 1696 | |
| 1697 | /* |
| 1698 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1699 | * return an appropriate error. |
| 1700 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1701 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1702 | { |
| 1703 | int ret; |
| 1704 | |
| 1705 | /* |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1706 | * Check pipe occupancy without the inode lock first. This function |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1707 | * is speculative anyways, so missing one is ok. |
| 1708 | */ |
Tetsuo Handa | 566d136 | 2020-05-20 08:51:59 +0900 | [diff] [blame] | 1709 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1710 | return 0; |
| 1711 | |
| 1712 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1713 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1714 | |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1715 | while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1716 | if (!pipe->readers) { |
| 1717 | send_sig(SIGPIPE, current, 0); |
| 1718 | ret = -EPIPE; |
| 1719 | break; |
| 1720 | } |
| 1721 | if (flags & SPLICE_F_NONBLOCK) { |
| 1722 | ret = -EAGAIN; |
| 1723 | break; |
| 1724 | } |
| 1725 | if (signal_pending(current)) { |
| 1726 | ret = -ERESTARTSYS; |
| 1727 | break; |
| 1728 | } |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1729 | pipe_wait_writable(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1730 | } |
| 1731 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1732 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1733 | return ret; |
| 1734 | } |
| 1735 | |
| 1736 | /* |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1737 | * Splice contents of ipipe to opipe. |
| 1738 | */ |
| 1739 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1740 | struct pipe_inode_info *opipe, |
| 1741 | size_t len, unsigned int flags) |
| 1742 | { |
| 1743 | struct pipe_buffer *ibuf, *obuf; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1744 | unsigned int i_head, o_head; |
| 1745 | unsigned int i_tail, o_tail; |
| 1746 | unsigned int i_mask, o_mask; |
| 1747 | int ret = 0; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1748 | bool input_wakeup = false; |
| 1749 | |
| 1750 | |
| 1751 | retry: |
| 1752 | ret = ipipe_prep(ipipe, flags); |
| 1753 | if (ret) |
| 1754 | return ret; |
| 1755 | |
| 1756 | ret = opipe_prep(opipe, flags); |
| 1757 | if (ret) |
| 1758 | return ret; |
| 1759 | |
| 1760 | /* |
| 1761 | * Potential ABBA deadlock, work around it by ordering lock |
| 1762 | * grabbing by pipe info address. Otherwise two different processes |
| 1763 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1764 | */ |
| 1765 | pipe_double_lock(ipipe, opipe); |
| 1766 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1767 | i_tail = ipipe->tail; |
| 1768 | i_mask = ipipe->ring_size - 1; |
| 1769 | o_head = opipe->head; |
| 1770 | o_mask = opipe->ring_size - 1; |
| 1771 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1772 | do { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1773 | size_t o_len; |
| 1774 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1775 | if (!opipe->readers) { |
| 1776 | send_sig(SIGPIPE, current, 0); |
| 1777 | if (!ret) |
| 1778 | ret = -EPIPE; |
| 1779 | break; |
| 1780 | } |
| 1781 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1782 | i_head = ipipe->head; |
| 1783 | o_tail = opipe->tail; |
| 1784 | |
| 1785 | if (pipe_empty(i_head, i_tail) && !ipipe->writers) |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1786 | break; |
| 1787 | |
| 1788 | /* |
| 1789 | * Cannot make any progress, because either the input |
| 1790 | * pipe is empty or the output pipe is full. |
| 1791 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1792 | if (pipe_empty(i_head, i_tail) || |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1793 | pipe_full(o_head, o_tail, opipe->max_usage)) { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1794 | /* Already processed some buffers, break */ |
| 1795 | if (ret) |
| 1796 | break; |
| 1797 | |
| 1798 | if (flags & SPLICE_F_NONBLOCK) { |
| 1799 | ret = -EAGAIN; |
| 1800 | break; |
| 1801 | } |
| 1802 | |
| 1803 | /* |
| 1804 | * We raced with another reader/writer and haven't |
| 1805 | * managed to process any buffers. A zero return |
| 1806 | * value means EOF, so retry instead. |
| 1807 | */ |
| 1808 | pipe_unlock(ipipe); |
| 1809 | pipe_unlock(opipe); |
| 1810 | goto retry; |
| 1811 | } |
| 1812 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1813 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
| 1814 | obuf = &opipe->bufs[o_head & o_mask]; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1815 | |
| 1816 | if (len >= ibuf->len) { |
| 1817 | /* |
| 1818 | * Simply move the whole buffer from ipipe to opipe |
| 1819 | */ |
| 1820 | *obuf = *ibuf; |
| 1821 | ibuf->ops = NULL; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1822 | i_tail++; |
| 1823 | ipipe->tail = i_tail; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1824 | input_wakeup = true; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1825 | o_len = obuf->len; |
| 1826 | o_head++; |
| 1827 | opipe->head = o_head; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1828 | } else { |
| 1829 | /* |
| 1830 | * Get a reference to this pipe buffer, |
| 1831 | * so we can copy the contents over. |
| 1832 | */ |
Matthew Wilcox | 15fab63 | 2019-04-05 14:02:10 -0700 | [diff] [blame] | 1833 | if (!pipe_buf_get(ipipe, ibuf)) { |
| 1834 | if (ret == 0) |
| 1835 | ret = -EFAULT; |
| 1836 | break; |
| 1837 | } |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1838 | *obuf = *ibuf; |
| 1839 | |
| 1840 | /* |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 1841 | * Don't inherit the gift and merge flags, we need to |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1842 | * prevent multiple steals of this page. |
| 1843 | */ |
| 1844 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 1845 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
Jann Horn | a0ce2f0 | 2019-01-23 15:19:17 +0100 | [diff] [blame] | 1846 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1847 | obuf->len = len; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1848 | ibuf->offset += len; |
| 1849 | ibuf->len -= len; |
| 1850 | o_len = len; |
| 1851 | o_head++; |
| 1852 | opipe->head = o_head; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1853 | } |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1854 | ret += o_len; |
| 1855 | len -= o_len; |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1856 | } while (len); |
| 1857 | |
| 1858 | pipe_unlock(ipipe); |
| 1859 | pipe_unlock(opipe); |
| 1860 | |
| 1861 | /* |
| 1862 | * If we put data in the output pipe, wakeup any potential readers. |
| 1863 | */ |
Namhyung Kim | 825cdcb | 2011-05-23 19:58:53 +0200 | [diff] [blame] | 1864 | if (ret > 0) |
| 1865 | wakeup_pipe_readers(opipe); |
| 1866 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1867 | if (input_wakeup) |
| 1868 | wakeup_pipe_writers(ipipe); |
| 1869 | |
| 1870 | return ret; |
| 1871 | } |
| 1872 | |
| 1873 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1874 | * Link contents of ipipe to opipe. |
| 1875 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1876 | static ssize_t link_pipe(struct pipe_inode_info *ipipe, |
| 1877 | struct pipe_inode_info *opipe, |
| 1878 | size_t len, unsigned int flags) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1879 | { |
| 1880 | struct pipe_buffer *ibuf, *obuf; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1881 | unsigned int i_head, o_head; |
| 1882 | unsigned int i_tail, o_tail; |
| 1883 | unsigned int i_mask, o_mask; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1884 | ssize_t ret = 0; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1885 | |
| 1886 | /* |
| 1887 | * Potential ABBA deadlock, work around it by ordering lock |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1888 | * grabbing by pipe info address. Otherwise two different processes |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1889 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1890 | */ |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1891 | pipe_double_lock(ipipe, opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1892 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1893 | i_tail = ipipe->tail; |
| 1894 | i_mask = ipipe->ring_size - 1; |
| 1895 | o_head = opipe->head; |
| 1896 | o_mask = opipe->ring_size - 1; |
| 1897 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1898 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1899 | if (!opipe->readers) { |
| 1900 | send_sig(SIGPIPE, current, 0); |
| 1901 | if (!ret) |
| 1902 | ret = -EPIPE; |
| 1903 | break; |
| 1904 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1905 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1906 | i_head = ipipe->head; |
| 1907 | o_tail = opipe->tail; |
| 1908 | |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1909 | /* |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1910 | * If we have iterated all input buffers or run out of |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1911 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1912 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1913 | if (pipe_empty(i_head, i_tail) || |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1914 | pipe_full(o_head, o_tail, opipe->max_usage)) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1915 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1916 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1917 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
| 1918 | obuf = &opipe->bufs[o_head & o_mask]; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1919 | |
Jens Axboe | 2a27250e | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1920 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1921 | * Get a reference to this pipe buffer, |
| 1922 | * so we can copy the contents over. |
Jens Axboe | 2a27250e | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1923 | */ |
Matthew Wilcox | 15fab63 | 2019-04-05 14:02:10 -0700 | [diff] [blame] | 1924 | if (!pipe_buf_get(ipipe, ibuf)) { |
| 1925 | if (ret == 0) |
| 1926 | ret = -EFAULT; |
| 1927 | break; |
| 1928 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1929 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1930 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1931 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1932 | /* |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 1933 | * Don't inherit the gift and merge flag, we need to prevent |
| 1934 | * multiple steals of this page. |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1935 | */ |
| 1936 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 1937 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
Jann Horn | a0ce2f0 | 2019-01-23 15:19:17 +0100 | [diff] [blame] | 1938 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1939 | if (obuf->len > len) |
| 1940 | obuf->len = len; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1941 | ret += obuf->len; |
| 1942 | len -= obuf->len; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1943 | |
| 1944 | o_head++; |
| 1945 | opipe->head = o_head; |
| 1946 | i_tail++; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1947 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1948 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1949 | pipe_unlock(ipipe); |
| 1950 | pipe_unlock(opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1951 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1952 | /* |
| 1953 | * If we put data in the output pipe, wakeup any potential readers. |
| 1954 | */ |
Namhyung Kim | 825cdcb | 2011-05-23 19:58:53 +0200 | [diff] [blame] | 1955 | if (ret > 0) |
| 1956 | wakeup_pipe_readers(opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1957 | |
| 1958 | return ret; |
| 1959 | } |
| 1960 | |
| 1961 | /* |
| 1962 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1963 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1964 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1965 | * applicable one is SPLICE_F_NONBLOCK. |
| 1966 | */ |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1967 | ssize_t do_tee(struct file *in, struct file *out, size_t len, |
| 1968 | unsigned int flags) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1969 | { |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1970 | struct pipe_inode_info *ipipe = get_pipe_info(in, true); |
| 1971 | struct pipe_inode_info *opipe = get_pipe_info(out, true); |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 1972 | ssize_t ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1973 | |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 1974 | if (unlikely(!(in->f_mode & FMODE_READ) || |
| 1975 | !(out->f_mode & FMODE_WRITE))) |
| 1976 | return -EBADF; |
| 1977 | |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1978 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1979 | * Duplicate the contents of ipipe to opipe without actually |
| 1980 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1981 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1982 | if (ipipe && opipe && ipipe != opipe) { |
Slavomir Kaslev | ee5e001 | 2019-02-07 17:45:19 +0200 | [diff] [blame] | 1983 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
| 1984 | flags |= SPLICE_F_NONBLOCK; |
| 1985 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1986 | /* |
| 1987 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1988 | * ordering doesn't really matter. |
| 1989 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1990 | ret = ipipe_prep(ipipe, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1991 | if (!ret) { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1992 | ret = opipe_prep(opipe, flags); |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1993 | if (!ret) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1994 | ret = link_pipe(ipipe, opipe, len, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1995 | } |
| 1996 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1997 | |
Ahelenia ZiemiaĆska | 576d498 | 2023-07-03 16:42:21 +0200 | [diff] [blame] | 1998 | if (ret > 0) { |
| 1999 | fsnotify_access(in); |
| 2000 | fsnotify_modify(out); |
| 2001 | } |
| 2002 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 2003 | return ret; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2004 | } |
| 2005 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 2006 | SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2007 | { |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 2008 | struct fd in, out; |
Amir Goldstein | 0f29208 | 2023-12-12 11:44:36 +0200 | [diff] [blame] | 2009 | ssize_t error; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2010 | |
Al Viro | 3d6ea29 | 2016-12-10 13:17:32 -0500 | [diff] [blame] | 2011 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 2012 | return -EINVAL; |
| 2013 | |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2014 | if (unlikely(!len)) |
| 2015 | return 0; |
| 2016 | |
| 2017 | error = -EBADF; |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2018 | in = fdget(fdin); |
| 2019 | if (in.file) { |
Pavel Begunkov | 90da2e3 | 2020-05-04 22:39:35 +0300 | [diff] [blame] | 2020 | out = fdget(fdout); |
| 2021 | if (out.file) { |
| 2022 | error = do_tee(in.file, out.file, len, flags); |
| 2023 | fdput(out); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2024 | } |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2025 | fdput(in); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2026 | } |
| 2027 | |
| 2028 | return error; |
| 2029 | } |