Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1 | /* |
| 2 | * "splice": joining two ropes together by interweaving their strands. |
| 3 | * |
| 4 | * This is the "extended pipe" functionality, where a pipe is used as |
| 5 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel |
| 6 | * buffer that you can use to transfer data from one end to the other. |
| 7 | * |
| 8 | * The traditional unix read/write is extended with a "splice()" operation |
| 9 | * that transfers data buffers to or from a pipe buffer. |
| 10 | * |
| 11 | * Named by Larry McVoy, original implementation from Linus, extended by |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 12 | * Jens to support splicing to files, network, direct splicing, etc and |
| 13 | * fixing lots of bugs. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 14 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 16 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
| 17 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 18 | * |
| 19 | */ |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/file.h> |
| 22 | #include <linux/pagemap.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 23 | #include <linux/splice.h> |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 24 | #include <linux/memcontrol.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 25 | #include <linux/mm_inline.h> |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 26 | #include <linux/swap.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 27 | #include <linux/writeback.h> |
| 28 | #include <linux/buffer_head.h> |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 29 | #include <linux/module.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 30 | #include <linux/syscalls.h> |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 31 | #include <linux/uio.h> |
James Morris | 29ce205 | 2007-07-13 11:44:32 +0200 | [diff] [blame] | 32 | #include <linux/security.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 33 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 34 | /* |
| 35 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 36 | * a vm helper function, it's already simplified quite a bit by the |
| 37 | * addition of remove_mapping(). If success is returned, the caller may |
| 38 | * attempt to reuse this page for another destination. |
| 39 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 40 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 41 | struct pipe_buffer *buf) |
| 42 | { |
| 43 | struct page *page = buf->page; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 44 | struct address_space *mapping; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 45 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 46 | lock_page(page); |
| 47 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 48 | mapping = page_mapping(page); |
| 49 | if (mapping) { |
| 50 | WARN_ON(!PageUptodate(page)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 51 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 52 | /* |
| 53 | * At least for ext2 with nobh option, we need to wait on |
| 54 | * writeback completing on this page, since we'll remove it |
| 55 | * from the pagecache. Otherwise truncate wont wait on the |
| 56 | * page, allowing the disk blocks to be reused by someone else |
| 57 | * before we actually wrote our data to them. fs corruption |
| 58 | * ensues. |
| 59 | */ |
| 60 | wait_on_page_writeback(page); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 61 | |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 62 | if (page_has_private(page) && |
| 63 | !try_to_release_page(page, GFP_KERNEL)) |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 64 | goto out_unlock; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 65 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 66 | /* |
| 67 | * If we succeeded in removing the mapping, set LRU flag |
| 68 | * and return good. |
| 69 | */ |
| 70 | if (remove_mapping(mapping, page)) { |
| 71 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 72 | return 0; |
| 73 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 74 | } |
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 | * Raced with truncate or failed to remove page from current |
| 78 | * address space, unlock and return failure. |
| 79 | */ |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 80 | out_unlock: |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 81 | unlock_page(page); |
| 82 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 83 | } |
| 84 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 85 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 86 | struct pipe_buffer *buf) |
| 87 | { |
| 88 | page_cache_release(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 89 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 90 | } |
| 91 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 92 | /* |
| 93 | * Check whether the contents of buf is OK to access. Since the content |
| 94 | * is a page cache page, IO may be in flight. |
| 95 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 96 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 97 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 98 | { |
| 99 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 100 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 101 | |
| 102 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 103 | lock_page(page); |
| 104 | |
| 105 | /* |
| 106 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 107 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 108 | */ |
| 109 | if (!page->mapping) { |
| 110 | err = -ENODATA; |
| 111 | goto error; |
| 112 | } |
| 113 | |
| 114 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 115 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 116 | */ |
| 117 | if (!PageUptodate(page)) { |
| 118 | err = -EIO; |
| 119 | goto error; |
| 120 | } |
| 121 | |
| 122 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 123 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 124 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 125 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 126 | } |
| 127 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 128 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 129 | error: |
| 130 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 131 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 132 | } |
| 133 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 134 | static const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 135 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 136 | .map = generic_pipe_buf_map, |
| 137 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 138 | .confirm = page_cache_pipe_buf_confirm, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 139 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 140 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 141 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 142 | }; |
| 143 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 144 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 145 | struct pipe_buffer *buf) |
| 146 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 147 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 148 | return 1; |
| 149 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 150 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 151 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 152 | } |
| 153 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 154 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 155 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 156 | .map = generic_pipe_buf_map, |
| 157 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 158 | .confirm = generic_pipe_buf_confirm, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 159 | .release = page_cache_pipe_buf_release, |
| 160 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 161 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 162 | }; |
| 163 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 164 | /** |
| 165 | * splice_to_pipe - fill passed data into a pipe |
| 166 | * @pipe: pipe to fill |
| 167 | * @spd: data to fill |
| 168 | * |
| 169 | * Description: |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 170 | * @spd contains a map of pages and len/offset tuples, along with |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 171 | * the struct pipe_buf_operations associated with these pages. This |
| 172 | * function will link that data to the pipe. |
| 173 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 174 | */ |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 175 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 176 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 177 | { |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 178 | unsigned int spd_pages = spd->nr_pages; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 179 | int ret, do_wakeup, page_nr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 180 | |
| 181 | ret = 0; |
| 182 | do_wakeup = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 183 | page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 184 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 185 | pipe_lock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 186 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 187 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 188 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 189 | send_sig(SIGPIPE, current, 0); |
| 190 | if (!ret) |
| 191 | ret = -EPIPE; |
| 192 | break; |
| 193 | } |
| 194 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 195 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 196 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 197 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 198 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 199 | buf->page = spd->pages[page_nr]; |
| 200 | buf->offset = spd->partial[page_nr].offset; |
| 201 | buf->len = spd->partial[page_nr].len; |
Jens Axboe | 497f962 | 2007-06-11 12:00:45 +0200 | [diff] [blame] | 202 | buf->private = spd->partial[page_nr].private; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 203 | buf->ops = spd->ops; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 204 | if (spd->flags & SPLICE_F_GIFT) |
| 205 | buf->flags |= PIPE_BUF_FLAG_GIFT; |
| 206 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 207 | pipe->nrbufs++; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 208 | page_nr++; |
| 209 | ret += buf->len; |
| 210 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 211 | if (pipe->inode) |
| 212 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 213 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 214 | if (!--spd->nr_pages) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 215 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 216 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 217 | continue; |
| 218 | |
| 219 | break; |
| 220 | } |
| 221 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 222 | if (spd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 223 | if (!ret) |
| 224 | ret = -EAGAIN; |
| 225 | break; |
| 226 | } |
| 227 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 228 | if (signal_pending(current)) { |
| 229 | if (!ret) |
| 230 | ret = -ERESTARTSYS; |
| 231 | break; |
| 232 | } |
| 233 | |
| 234 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 235 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 236 | if (waitqueue_active(&pipe->wait)) |
| 237 | wake_up_interruptible_sync(&pipe->wait); |
| 238 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 239 | do_wakeup = 0; |
| 240 | } |
| 241 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 242 | pipe->waiting_writers++; |
| 243 | pipe_wait(pipe); |
| 244 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 245 | } |
| 246 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 247 | pipe_unlock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 248 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 249 | if (do_wakeup) { |
| 250 | smp_mb(); |
| 251 | if (waitqueue_active(&pipe->wait)) |
| 252 | wake_up_interruptible(&pipe->wait); |
| 253 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 254 | } |
| 255 | |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 256 | while (page_nr < spd_pages) |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 257 | spd->spd_release(spd, page_nr++); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 258 | |
| 259 | return ret; |
| 260 | } |
| 261 | |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 262 | static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) |
| 263 | { |
| 264 | page_cache_release(spd->pages[i]); |
| 265 | } |
| 266 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 267 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 268 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 269 | struct pipe_inode_info *pipe, size_t len, |
| 270 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 271 | { |
| 272 | struct address_space *mapping = in->f_mapping; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 273 | unsigned int loff, nr_pages, req_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 274 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 275 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 276 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 277 | pgoff_t index, end_index; |
| 278 | loff_t isize; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 279 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 280 | struct splice_pipe_desc spd = { |
| 281 | .pages = pages, |
| 282 | .partial = partial, |
| 283 | .flags = flags, |
| 284 | .ops = &page_cache_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 285 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 286 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 287 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 288 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 289 | loff = *ppos & ~PAGE_CACHE_MASK; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 290 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 291 | nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 292 | |
| 293 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 294 | * Lookup the (hopefully) full range of pages we need. |
| 295 | */ |
| 296 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 297 | index += spd.nr_pages; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 298 | |
| 299 | /* |
| 300 | * If find_get_pages_contig() returned fewer pages than we needed, |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 301 | * readahead/allocate the rest and fill in the holes. |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 302 | */ |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 303 | if (spd.nr_pages < nr_pages) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 304 | page_cache_sync_readahead(mapping, &in->f_ra, in, |
| 305 | index, req_pages - spd.nr_pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 306 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 307 | error = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 308 | while (spd.nr_pages < nr_pages) { |
| 309 | /* |
| 310 | * Page could be there, find_get_pages_contig() breaks on |
| 311 | * the first hole. |
| 312 | */ |
| 313 | page = find_get_page(mapping, index); |
| 314 | if (!page) { |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 315 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 316 | * page didn't exist, allocate one. |
| 317 | */ |
| 318 | page = page_cache_alloc_cold(mapping); |
| 319 | if (!page) |
| 320 | break; |
| 321 | |
| 322 | error = add_to_page_cache_lru(page, mapping, index, |
Hugh Dickins | 4cd1350 | 2008-04-03 23:35:22 +0100 | [diff] [blame] | 323 | mapping_gfp_mask(mapping)); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 324 | if (unlikely(error)) { |
| 325 | page_cache_release(page); |
Jens Axboe | a054887 | 2006-05-03 10:58:22 +0200 | [diff] [blame] | 326 | if (error == -EEXIST) |
| 327 | continue; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 328 | break; |
| 329 | } |
| 330 | /* |
| 331 | * add_to_page_cache() locks the page, unlock it |
| 332 | * to avoid convoluting the logic below even more. |
| 333 | */ |
| 334 | unlock_page(page); |
| 335 | } |
| 336 | |
| 337 | pages[spd.nr_pages++] = page; |
| 338 | index++; |
| 339 | } |
| 340 | |
| 341 | /* |
| 342 | * Now loop over the map and see if we need to start IO on any |
| 343 | * pages, fill in the partial map, etc. |
| 344 | */ |
| 345 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 346 | nr_pages = spd.nr_pages; |
| 347 | spd.nr_pages = 0; |
| 348 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 349 | unsigned int this_len; |
| 350 | |
| 351 | if (!len) |
| 352 | break; |
| 353 | |
| 354 | /* |
| 355 | * this_len is the max we'll use from this page |
| 356 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 357 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 358 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 359 | |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 360 | if (PageReadahead(page)) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 361 | page_cache_async_readahead(mapping, &in->f_ra, in, |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 362 | page, index, req_pages - page_nr); |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 363 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 364 | /* |
| 365 | * If the page isn't uptodate, we may need to start io on it |
| 366 | */ |
| 367 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 368 | /* |
| 369 | * If in nonblock mode then dont block on waiting |
| 370 | * for an in-flight io page |
| 371 | */ |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 372 | if (flags & SPLICE_F_NONBLOCK) { |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 373 | if (!trylock_page(page)) { |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 374 | error = -EAGAIN; |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 375 | break; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 376 | } |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 377 | } else |
| 378 | lock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 379 | |
| 380 | /* |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 381 | * Page was truncated, or invalidated by the |
| 382 | * filesystem. Redo the find/create, but this time the |
| 383 | * page is kept locked, so there's no chance of another |
| 384 | * race with truncate/invalidate. |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 385 | */ |
| 386 | if (!page->mapping) { |
| 387 | unlock_page(page); |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 388 | page = find_or_create_page(mapping, index, |
| 389 | mapping_gfp_mask(mapping)); |
| 390 | |
| 391 | if (!page) { |
| 392 | error = -ENOMEM; |
| 393 | break; |
| 394 | } |
| 395 | page_cache_release(pages[page_nr]); |
| 396 | pages[page_nr] = page; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 397 | } |
| 398 | /* |
| 399 | * page was already under io and is now done, great |
| 400 | */ |
| 401 | if (PageUptodate(page)) { |
| 402 | unlock_page(page); |
| 403 | goto fill_it; |
| 404 | } |
| 405 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 406 | /* |
| 407 | * need to read in the page |
| 408 | */ |
| 409 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 410 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 411 | /* |
| 412 | * We really should re-lookup the page here, |
| 413 | * but it complicates things a lot. Instead |
| 414 | * lets just do what we already stored, and |
| 415 | * we'll get it the next time we are called. |
| 416 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 417 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 418 | error = 0; |
| 419 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 420 | break; |
| 421 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 422 | } |
| 423 | fill_it: |
| 424 | /* |
| 425 | * i_size must be checked after PageUptodate. |
| 426 | */ |
| 427 | isize = i_size_read(mapping->host); |
| 428 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 429 | if (unlikely(!isize || index > end_index)) |
| 430 | break; |
| 431 | |
| 432 | /* |
| 433 | * if this is the last page, see if we need to shrink |
| 434 | * the length and stop |
| 435 | */ |
| 436 | if (end_index == index) { |
| 437 | unsigned int plen; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 438 | |
| 439 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 440 | * max good bytes in this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 441 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 442 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 443 | if (plen <= loff) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 444 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 445 | |
| 446 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 447 | * force quit after adding this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 448 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 449 | this_len = min(this_len, plen - loff); |
| 450 | len = this_len; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 451 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 452 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 453 | partial[page_nr].offset = loff; |
| 454 | partial[page_nr].len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 455 | len -= this_len; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 456 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 457 | spd.nr_pages++; |
| 458 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 459 | } |
| 460 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 461 | /* |
Hugh Dickins | 475ecad | 2007-06-07 09:36:00 +0200 | [diff] [blame] | 462 | * Release any pages at the end, if we quit early. 'page_nr' is how far |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 463 | * we got, 'nr_pages' is how many pages are in the map. |
| 464 | */ |
| 465 | while (page_nr < nr_pages) |
| 466 | page_cache_release(pages[page_nr++]); |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 467 | in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 468 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 469 | if (spd.nr_pages) |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 470 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 471 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 472 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 473 | } |
| 474 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 475 | /** |
| 476 | * generic_file_splice_read - splice data from file to a pipe |
| 477 | * @in: file to splice from |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 478 | * @ppos: position in @in |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 479 | * @pipe: pipe to splice to |
| 480 | * @len: number of bytes to splice |
| 481 | * @flags: splice modifier flags |
| 482 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 483 | * Description: |
| 484 | * Will read pages from given file and fill them into a pipe. Can be |
| 485 | * used as long as the address_space operations for the source implements |
| 486 | * a readpage() hook. |
| 487 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 488 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 489 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 490 | struct pipe_inode_info *pipe, size_t len, |
| 491 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 492 | { |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 493 | loff_t isize, left; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 494 | int ret; |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 495 | |
| 496 | isize = i_size_read(in->f_mapping->host); |
| 497 | if (unlikely(*ppos >= isize)) |
| 498 | return 0; |
| 499 | |
| 500 | left = isize - *ppos; |
| 501 | if (unlikely(left < len)) |
| 502 | len = left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 503 | |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 504 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame^] | 505 | if (ret > 0) { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 506 | *ppos += ret; |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame^] | 507 | file_accessed(in); |
| 508 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 509 | |
| 510 | return ret; |
| 511 | } |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 512 | EXPORT_SYMBOL(generic_file_splice_read); |
| 513 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 514 | static const struct pipe_buf_operations default_pipe_buf_ops = { |
| 515 | .can_merge = 0, |
| 516 | .map = generic_pipe_buf_map, |
| 517 | .unmap = generic_pipe_buf_unmap, |
| 518 | .confirm = generic_pipe_buf_confirm, |
| 519 | .release = generic_pipe_buf_release, |
| 520 | .steal = generic_pipe_buf_steal, |
| 521 | .get = generic_pipe_buf_get, |
| 522 | }; |
| 523 | |
| 524 | static ssize_t kernel_readv(struct file *file, const struct iovec *vec, |
| 525 | unsigned long vlen, loff_t offset) |
| 526 | { |
| 527 | mm_segment_t old_fs; |
| 528 | loff_t pos = offset; |
| 529 | ssize_t res; |
| 530 | |
| 531 | old_fs = get_fs(); |
| 532 | set_fs(get_ds()); |
| 533 | /* The cast to a user pointer is valid due to the set_fs() */ |
| 534 | res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos); |
| 535 | set_fs(old_fs); |
| 536 | |
| 537 | return res; |
| 538 | } |
| 539 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 540 | static ssize_t kernel_write(struct file *file, const char *buf, size_t count, |
| 541 | loff_t pos) |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 542 | { |
| 543 | mm_segment_t old_fs; |
| 544 | ssize_t res; |
| 545 | |
| 546 | old_fs = get_fs(); |
| 547 | set_fs(get_ds()); |
| 548 | /* The cast to a user pointer is valid due to the set_fs() */ |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 549 | res = vfs_write(file, (const char __user *)buf, count, &pos); |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 550 | set_fs(old_fs); |
| 551 | |
| 552 | return res; |
| 553 | } |
| 554 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 555 | ssize_t default_file_splice_read(struct file *in, loff_t *ppos, |
| 556 | struct pipe_inode_info *pipe, size_t len, |
| 557 | unsigned int flags) |
| 558 | { |
| 559 | unsigned int nr_pages; |
| 560 | unsigned int nr_freed; |
| 561 | size_t offset; |
| 562 | struct page *pages[PIPE_BUFFERS]; |
| 563 | struct partial_page partial[PIPE_BUFFERS]; |
| 564 | struct iovec vec[PIPE_BUFFERS]; |
| 565 | pgoff_t index; |
| 566 | ssize_t res; |
| 567 | size_t this_len; |
| 568 | int error; |
| 569 | int i; |
| 570 | struct splice_pipe_desc spd = { |
| 571 | .pages = pages, |
| 572 | .partial = partial, |
| 573 | .flags = flags, |
| 574 | .ops = &default_pipe_buf_ops, |
| 575 | .spd_release = spd_release_page, |
| 576 | }; |
| 577 | |
| 578 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 579 | offset = *ppos & ~PAGE_CACHE_MASK; |
| 580 | nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 581 | |
| 582 | for (i = 0; i < nr_pages && i < PIPE_BUFFERS && len; i++) { |
| 583 | struct page *page; |
| 584 | |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 585 | page = alloc_page(GFP_USER); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 586 | error = -ENOMEM; |
| 587 | if (!page) |
| 588 | goto err; |
| 589 | |
| 590 | this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset); |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 591 | vec[i].iov_base = (void __user *) page_address(page); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 592 | vec[i].iov_len = this_len; |
| 593 | pages[i] = page; |
| 594 | spd.nr_pages++; |
| 595 | len -= this_len; |
| 596 | offset = 0; |
| 597 | } |
| 598 | |
| 599 | res = kernel_readv(in, vec, spd.nr_pages, *ppos); |
Andrew Morton | 77f6bf5 | 2009-05-14 09:49:44 +0200 | [diff] [blame] | 600 | if (res < 0) { |
| 601 | error = res; |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 602 | goto err; |
Andrew Morton | 77f6bf5 | 2009-05-14 09:49:44 +0200 | [diff] [blame] | 603 | } |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 604 | |
| 605 | error = 0; |
| 606 | if (!res) |
| 607 | goto err; |
| 608 | |
| 609 | nr_freed = 0; |
| 610 | for (i = 0; i < spd.nr_pages; i++) { |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 611 | this_len = min_t(size_t, vec[i].iov_len, res); |
| 612 | partial[i].offset = 0; |
| 613 | partial[i].len = this_len; |
| 614 | if (!this_len) { |
| 615 | __free_page(pages[i]); |
| 616 | pages[i] = NULL; |
| 617 | nr_freed++; |
| 618 | } |
| 619 | res -= this_len; |
| 620 | } |
| 621 | spd.nr_pages -= nr_freed; |
| 622 | |
| 623 | res = splice_to_pipe(pipe, &spd); |
| 624 | if (res > 0) |
| 625 | *ppos += res; |
| 626 | |
| 627 | return res; |
| 628 | |
| 629 | err: |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 630 | for (i = 0; i < spd.nr_pages; i++) |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 631 | __free_page(pages[i]); |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 632 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 633 | return error; |
| 634 | } |
| 635 | EXPORT_SYMBOL(default_file_splice_read); |
| 636 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 637 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 638 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 639 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 640 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 641 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 642 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 643 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 644 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 645 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 646 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 647 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 648 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 649 | if (!ret) { |
| 650 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 651 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 652 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 653 | sd->len, &pos, more); |
| 654 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 655 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 656 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 657 | } |
| 658 | |
| 659 | /* |
| 660 | * This is a little more tricky than the file -> pipe splicing. There are |
| 661 | * basically three cases: |
| 662 | * |
| 663 | * - Destination page already exists in the address space and there |
| 664 | * are users of it. For that case we have no other option that |
| 665 | * copying the data. Tough luck. |
| 666 | * - Destination page already exists in the address space, but there |
| 667 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 668 | * through to last case. |
| 669 | * - Destination page does not exist, we can add the pipe page to |
| 670 | * the page cache and avoid the copy. |
| 671 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 672 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 673 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 674 | * file address space page cache. This is possible if no one else has |
| 675 | * the pipe page referenced outside of the pipe and page cache. If |
| 676 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 677 | * a new page in the output file page cache and fill/dirty that. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 678 | */ |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 679 | int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 680 | struct splice_desc *sd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 681 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 682 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 683 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 684 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 685 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 686 | void *fsdata; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 687 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 688 | |
| 689 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 690 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 691 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 692 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 693 | if (unlikely(ret)) |
| 694 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 695 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 696 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 697 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 698 | this_len = sd->len; |
| 699 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 700 | this_len = PAGE_CACHE_SIZE - offset; |
| 701 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 702 | ret = pagecache_write_begin(file, mapping, sd->pos, this_len, |
| 703 | AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); |
| 704 | if (unlikely(ret)) |
| 705 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 706 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 707 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 708 | /* |
| 709 | * Careful, ->map() uses KM_USER0! |
| 710 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 711 | char *src = buf->ops->map(pipe, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 712 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 713 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 714 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 715 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 716 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 717 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 718 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 719 | ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, |
| 720 | page, fsdata); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 721 | out: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 722 | return ret; |
| 723 | } |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 724 | EXPORT_SYMBOL(pipe_to_file); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 725 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 726 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
| 727 | { |
| 728 | smp_mb(); |
| 729 | if (waitqueue_active(&pipe->wait)) |
| 730 | wake_up_interruptible(&pipe->wait); |
| 731 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
| 732 | } |
| 733 | |
| 734 | /** |
| 735 | * splice_from_pipe_feed - feed available data from a pipe to a file |
| 736 | * @pipe: pipe to splice from |
| 737 | * @sd: information to @actor |
| 738 | * @actor: handler that splices the data |
| 739 | * |
| 740 | * Description: |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 741 | * This function loops over the pipe and calls @actor to do the |
| 742 | * actual moving of a single struct pipe_buffer to the desired |
| 743 | * destination. It returns when there's no more buffers left in |
| 744 | * the pipe or if the requested number of bytes (@sd->total_len) |
| 745 | * have been copied. It returns a positive number (one) if the |
| 746 | * pipe needs to be filled with more data, zero if the required |
| 747 | * number of bytes have been copied and -errno on error. |
| 748 | * |
| 749 | * This, together with splice_from_pipe_{begin,end,next}, may be |
| 750 | * used to implement the functionality of __splice_from_pipe() when |
| 751 | * locking is required around copying the pipe buffers to the |
| 752 | * destination. |
| 753 | */ |
| 754 | int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 755 | splice_actor *actor) |
| 756 | { |
| 757 | int ret; |
| 758 | |
| 759 | while (pipe->nrbufs) { |
| 760 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
| 761 | const struct pipe_buf_operations *ops = buf->ops; |
| 762 | |
| 763 | sd->len = buf->len; |
| 764 | if (sd->len > sd->total_len) |
| 765 | sd->len = sd->total_len; |
| 766 | |
| 767 | ret = actor(pipe, buf, sd); |
| 768 | if (ret <= 0) { |
| 769 | if (ret == -ENODATA) |
| 770 | ret = 0; |
| 771 | return ret; |
| 772 | } |
| 773 | buf->offset += ret; |
| 774 | buf->len -= ret; |
| 775 | |
| 776 | sd->num_spliced += ret; |
| 777 | sd->len -= ret; |
| 778 | sd->pos += ret; |
| 779 | sd->total_len -= ret; |
| 780 | |
| 781 | if (!buf->len) { |
| 782 | buf->ops = NULL; |
| 783 | ops->release(pipe, buf); |
| 784 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 785 | pipe->nrbufs--; |
| 786 | if (pipe->inode) |
| 787 | sd->need_wakeup = true; |
| 788 | } |
| 789 | |
| 790 | if (!sd->total_len) |
| 791 | return 0; |
| 792 | } |
| 793 | |
| 794 | return 1; |
| 795 | } |
| 796 | EXPORT_SYMBOL(splice_from_pipe_feed); |
| 797 | |
| 798 | /** |
| 799 | * splice_from_pipe_next - wait for some data to splice from |
| 800 | * @pipe: pipe to splice from |
| 801 | * @sd: information about the splice operation |
| 802 | * |
| 803 | * Description: |
| 804 | * This function will wait for some data and return a positive |
| 805 | * value (one) if pipe buffers are available. It will return zero |
| 806 | * or -errno if no more data needs to be spliced. |
| 807 | */ |
| 808 | int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 809 | { |
| 810 | while (!pipe->nrbufs) { |
| 811 | if (!pipe->writers) |
| 812 | return 0; |
| 813 | |
| 814 | if (!pipe->waiting_writers && sd->num_spliced) |
| 815 | return 0; |
| 816 | |
| 817 | if (sd->flags & SPLICE_F_NONBLOCK) |
| 818 | return -EAGAIN; |
| 819 | |
| 820 | if (signal_pending(current)) |
| 821 | return -ERESTARTSYS; |
| 822 | |
| 823 | if (sd->need_wakeup) { |
| 824 | wakeup_pipe_writers(pipe); |
| 825 | sd->need_wakeup = false; |
| 826 | } |
| 827 | |
| 828 | pipe_wait(pipe); |
| 829 | } |
| 830 | |
| 831 | return 1; |
| 832 | } |
| 833 | EXPORT_SYMBOL(splice_from_pipe_next); |
| 834 | |
| 835 | /** |
| 836 | * splice_from_pipe_begin - start splicing from pipe |
Randy Dunlap | b80901b | 2009-04-16 19:09:55 -0700 | [diff] [blame] | 837 | * @sd: information about the splice operation |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 838 | * |
| 839 | * Description: |
| 840 | * This function should be called before a loop containing |
| 841 | * splice_from_pipe_next() and splice_from_pipe_feed() to |
| 842 | * initialize the necessary fields of @sd. |
| 843 | */ |
| 844 | void splice_from_pipe_begin(struct splice_desc *sd) |
| 845 | { |
| 846 | sd->num_spliced = 0; |
| 847 | sd->need_wakeup = false; |
| 848 | } |
| 849 | EXPORT_SYMBOL(splice_from_pipe_begin); |
| 850 | |
| 851 | /** |
| 852 | * splice_from_pipe_end - finish splicing from pipe |
| 853 | * @pipe: pipe to splice from |
| 854 | * @sd: information about the splice operation |
| 855 | * |
| 856 | * Description: |
| 857 | * This function will wake up pipe writers if necessary. It should |
| 858 | * be called after a loop containing splice_from_pipe_next() and |
| 859 | * splice_from_pipe_feed(). |
| 860 | */ |
| 861 | void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 862 | { |
| 863 | if (sd->need_wakeup) |
| 864 | wakeup_pipe_writers(pipe); |
| 865 | } |
| 866 | EXPORT_SYMBOL(splice_from_pipe_end); |
| 867 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 868 | /** |
| 869 | * __splice_from_pipe - splice data from a pipe to given actor |
| 870 | * @pipe: pipe to splice from |
| 871 | * @sd: information to @actor |
| 872 | * @actor: handler that splices the data |
| 873 | * |
| 874 | * Description: |
| 875 | * This function does little more than loop over the pipe and call |
| 876 | * @actor to do the actual moving of a single struct pipe_buffer to |
| 877 | * the desired destination. See pipe_to_file, pipe_to_sendpage, or |
| 878 | * pipe_to_user. |
| 879 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 880 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 881 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 882 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 883 | { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 884 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 885 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 886 | splice_from_pipe_begin(sd); |
| 887 | do { |
| 888 | ret = splice_from_pipe_next(pipe, sd); |
| 889 | if (ret > 0) |
| 890 | ret = splice_from_pipe_feed(pipe, sd, actor); |
| 891 | } while (ret > 0); |
| 892 | splice_from_pipe_end(pipe, sd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 893 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 894 | return sd->num_spliced ? sd->num_spliced : ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 895 | } |
Mark Fasheh | 40bee44 | 2007-03-21 13:11:02 +0100 | [diff] [blame] | 896 | EXPORT_SYMBOL(__splice_from_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 897 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 898 | /** |
| 899 | * splice_from_pipe - splice data from a pipe to a file |
| 900 | * @pipe: pipe to splice from |
| 901 | * @out: file to splice to |
| 902 | * @ppos: position in @out |
| 903 | * @len: how many bytes to splice |
| 904 | * @flags: splice modifier flags |
| 905 | * @actor: handler that splices the data |
| 906 | * |
| 907 | * Description: |
Miklos Szeredi | 2933970 | 2009-04-14 19:48:37 +0200 | [diff] [blame] | 908 | * See __splice_from_pipe. This function locks the pipe inode, |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 909 | * otherwise it's identical to __splice_from_pipe(). |
| 910 | * |
| 911 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 912 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 913 | loff_t *ppos, size_t len, unsigned int flags, |
| 914 | splice_actor *actor) |
| 915 | { |
| 916 | ssize_t ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 917 | struct splice_desc sd = { |
| 918 | .total_len = len, |
| 919 | .flags = flags, |
| 920 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 921 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 922 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 923 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 924 | pipe_lock(pipe); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 925 | ret = __splice_from_pipe(pipe, &sd, actor); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 926 | pipe_unlock(pipe); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 927 | |
| 928 | return ret; |
| 929 | } |
| 930 | |
| 931 | /** |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 932 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 933 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 934 | * @out: file to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 935 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 936 | * @len: number of bytes to splice |
| 937 | * @flags: splice modifier flags |
| 938 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 939 | * Description: |
| 940 | * Will either move or copy pages (determined by @flags options) from |
| 941 | * the given pipe inode to the given file. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 942 | * |
| 943 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 944 | ssize_t |
| 945 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 946 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 947 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 948 | struct address_space *mapping = out->f_mapping; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 949 | struct inode *inode = mapping->host; |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 950 | struct splice_desc sd = { |
| 951 | .total_len = len, |
| 952 | .flags = flags, |
| 953 | .pos = *ppos, |
| 954 | .u.file = out, |
| 955 | }; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 956 | ssize_t ret; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 957 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 958 | pipe_lock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 959 | |
| 960 | splice_from_pipe_begin(&sd); |
| 961 | do { |
| 962 | ret = splice_from_pipe_next(pipe, &sd); |
| 963 | if (ret <= 0) |
| 964 | break; |
| 965 | |
| 966 | mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); |
| 967 | ret = file_remove_suid(out); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame^] | 968 | if (!ret) { |
| 969 | file_update_time(out); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 970 | ret = splice_from_pipe_feed(pipe, &sd, pipe_to_file); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame^] | 971 | } |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 972 | mutex_unlock(&inode->i_mutex); |
| 973 | } while (ret > 0); |
| 974 | splice_from_pipe_end(pipe, &sd); |
| 975 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 976 | pipe_unlock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 977 | |
| 978 | if (sd.num_spliced) |
| 979 | ret = sd.num_spliced; |
| 980 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 981 | if (ret > 0) { |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 982 | unsigned long nr_pages; |
| 983 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 984 | *ppos += ret; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 985 | nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 986 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 987 | /* |
| 988 | * If file or inode is SYNC and we actually wrote some data, |
| 989 | * sync it. |
| 990 | */ |
| 991 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 992 | int err; |
| 993 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 994 | mutex_lock(&inode->i_mutex); |
| 995 | err = generic_osync_inode(inode, mapping, |
| 996 | OSYNC_METADATA|OSYNC_DATA); |
| 997 | mutex_unlock(&inode->i_mutex); |
| 998 | |
| 999 | if (err) |
| 1000 | ret = err; |
| 1001 | } |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 1002 | balance_dirty_pages_ratelimited_nr(mapping, nr_pages); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 1003 | } |
| 1004 | |
| 1005 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1006 | } |
| 1007 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 1008 | EXPORT_SYMBOL(generic_file_splice_write); |
| 1009 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1010 | static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1011 | struct splice_desc *sd) |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1012 | { |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1013 | int ret; |
| 1014 | void *data; |
| 1015 | |
| 1016 | ret = buf->ops->confirm(pipe, buf); |
| 1017 | if (ret) |
| 1018 | return ret; |
| 1019 | |
| 1020 | data = buf->ops->map(pipe, buf, 0); |
| 1021 | ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos); |
| 1022 | buf->ops->unmap(pipe, buf, data); |
| 1023 | |
| 1024 | return ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1025 | } |
| 1026 | |
| 1027 | static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, |
| 1028 | struct file *out, loff_t *ppos, |
| 1029 | size_t len, unsigned int flags) |
| 1030 | { |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1031 | ssize_t ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1032 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1033 | ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); |
| 1034 | if (ret > 0) |
| 1035 | *ppos += ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1036 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1037 | return ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1038 | } |
| 1039 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1040 | /** |
| 1041 | * generic_splice_sendpage - splice data from a pipe to a socket |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1042 | * @pipe: pipe to splice from |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1043 | * @out: socket to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1044 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1045 | * @len: number of bytes to splice |
| 1046 | * @flags: splice modifier flags |
| 1047 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1048 | * Description: |
| 1049 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 1050 | * is involved. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1051 | * |
| 1052 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1053 | ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1054 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1055 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1056 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1057 | } |
| 1058 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 1059 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 1060 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1061 | /* |
| 1062 | * Attempt to initiate a splice from pipe to file. |
| 1063 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1064 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1065 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1066 | { |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1067 | ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, |
| 1068 | loff_t *, size_t, unsigned int); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1069 | int ret; |
| 1070 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1071 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1072 | return -EBADF; |
| 1073 | |
Linus Torvalds | efc968d | 2008-10-09 14:04:54 -0700 | [diff] [blame] | 1074 | if (unlikely(out->f_flags & O_APPEND)) |
| 1075 | return -EINVAL; |
| 1076 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1077 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1078 | if (unlikely(ret < 0)) |
| 1079 | return ret; |
| 1080 | |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1081 | splice_write = out->f_op->splice_write; |
| 1082 | if (!splice_write) |
| 1083 | splice_write = default_file_splice_write; |
| 1084 | |
| 1085 | return splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1086 | } |
| 1087 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1088 | /* |
| 1089 | * Attempt to initiate a splice from a file to a pipe. |
| 1090 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1091 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 1092 | struct pipe_inode_info *pipe, size_t len, |
| 1093 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1094 | { |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 1095 | ssize_t (*splice_read)(struct file *, loff_t *, |
| 1096 | struct pipe_inode_info *, size_t, unsigned int); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1097 | int ret; |
| 1098 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1099 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1100 | return -EBADF; |
| 1101 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1102 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1103 | if (unlikely(ret < 0)) |
| 1104 | return ret; |
| 1105 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 1106 | splice_read = in->f_op->splice_read; |
| 1107 | if (!splice_read) |
| 1108 | splice_read = default_file_splice_read; |
| 1109 | |
| 1110 | return splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1111 | } |
| 1112 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1113 | /** |
| 1114 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 1115 | * @in: file to splice from |
| 1116 | * @sd: actor information on where to splice to |
| 1117 | * @actor: handles the data splicing |
| 1118 | * |
| 1119 | * Description: |
| 1120 | * This is a special case helper to splice directly between two |
| 1121 | * points, without requiring an explicit pipe. Internally an allocated |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 1122 | * pipe is cached in the process, and reused during the lifetime of |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1123 | * that process. |
| 1124 | * |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1125 | */ |
| 1126 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 1127 | splice_direct_actor *actor) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1128 | { |
| 1129 | struct pipe_inode_info *pipe; |
| 1130 | long ret, bytes; |
| 1131 | umode_t i_mode; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1132 | size_t len; |
| 1133 | int i, flags; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1134 | |
| 1135 | /* |
| 1136 | * We require the input being a regular file, as we don't want to |
| 1137 | * randomly drop data for eg socket -> socket splicing. Use the |
| 1138 | * piped splicing for that! |
| 1139 | */ |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1140 | i_mode = in->f_path.dentry->d_inode->i_mode; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1141 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 1142 | return -EINVAL; |
| 1143 | |
| 1144 | /* |
| 1145 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 1146 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 1147 | */ |
| 1148 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1149 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1150 | pipe = alloc_pipe_info(NULL); |
| 1151 | if (!pipe) |
| 1152 | return -ENOMEM; |
| 1153 | |
| 1154 | /* |
| 1155 | * 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] | 1156 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1157 | * PIPE_READERS appropriately. |
| 1158 | */ |
| 1159 | pipe->readers = 1; |
| 1160 | |
| 1161 | current->splice_pipe = pipe; |
| 1162 | } |
| 1163 | |
| 1164 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 1165 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1166 | */ |
| 1167 | ret = 0; |
| 1168 | bytes = 0; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1169 | len = sd->total_len; |
| 1170 | flags = sd->flags; |
| 1171 | |
| 1172 | /* |
| 1173 | * Don't block on output, we have to drain the direct pipe. |
| 1174 | */ |
| 1175 | sd->flags &= ~SPLICE_F_NONBLOCK; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1176 | |
| 1177 | while (len) { |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1178 | size_t read_len; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1179 | loff_t pos = sd->pos, prev_pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1180 | |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1181 | ret = do_splice_to(in, &pos, pipe, len, flags); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1182 | if (unlikely(ret <= 0)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1183 | goto out_release; |
| 1184 | |
| 1185 | read_len = ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1186 | sd->total_len = read_len; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1187 | |
| 1188 | /* |
| 1189 | * NOTE: nonblocking mode only applies to the input. We |
| 1190 | * must not do the output in nonblocking mode as then we |
| 1191 | * could get stuck data in the internal pipe: |
| 1192 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1193 | ret = actor(pipe, sd); |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1194 | if (unlikely(ret <= 0)) { |
| 1195 | sd->pos = prev_pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1196 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1197 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1198 | |
| 1199 | bytes += ret; |
| 1200 | len -= ret; |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1201 | sd->pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1202 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1203 | if (ret < read_len) { |
| 1204 | sd->pos = prev_pos + ret; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1205 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1206 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1207 | } |
| 1208 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1209 | done: |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1210 | pipe->nrbufs = pipe->curbuf = 0; |
Jens Axboe | 8084870 | 2008-01-30 12:24:48 +0100 | [diff] [blame] | 1211 | file_accessed(in); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1212 | return bytes; |
| 1213 | |
| 1214 | out_release: |
| 1215 | /* |
| 1216 | * If we did an incomplete transfer we must release |
| 1217 | * the pipe buffers in question: |
| 1218 | */ |
| 1219 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1220 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1221 | |
| 1222 | if (buf->ops) { |
| 1223 | buf->ops->release(pipe, buf); |
| 1224 | buf->ops = NULL; |
| 1225 | } |
| 1226 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1227 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1228 | if (!bytes) |
| 1229 | bytes = ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1230 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1231 | goto done; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1232 | } |
| 1233 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1234 | |
| 1235 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1236 | struct splice_desc *sd) |
| 1237 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1238 | struct file *file = sd->u.file; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1239 | |
| 1240 | return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); |
| 1241 | } |
| 1242 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1243 | /** |
| 1244 | * do_splice_direct - splices data directly between two files |
| 1245 | * @in: file to splice from |
| 1246 | * @ppos: input file offset |
| 1247 | * @out: file to splice to |
| 1248 | * @len: number of bytes to splice |
| 1249 | * @flags: splice modifier flags |
| 1250 | * |
| 1251 | * Description: |
| 1252 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1253 | * doing it in the application would incur an extra system call |
| 1254 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1255 | * can splice directly through a process-private pipe. |
| 1256 | * |
| 1257 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1258 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1259 | size_t len, unsigned int flags) |
| 1260 | { |
| 1261 | struct splice_desc sd = { |
| 1262 | .len = len, |
| 1263 | .total_len = len, |
| 1264 | .flags = flags, |
| 1265 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1266 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1267 | }; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1268 | long ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1269 | |
| 1270 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1271 | if (ret > 0) |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1272 | *ppos = sd.pos; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1273 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1274 | return ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1275 | } |
| 1276 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1277 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1278 | struct pipe_inode_info *opipe, |
| 1279 | size_t len, unsigned int flags); |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1280 | /* |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1281 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same |
| 1282 | * location, so checking ->i_pipe is not enough to verify that this is a |
| 1283 | * pipe. |
| 1284 | */ |
| 1285 | static inline struct pipe_inode_info *pipe_info(struct inode *inode) |
| 1286 | { |
| 1287 | if (S_ISFIFO(inode->i_mode)) |
| 1288 | return inode->i_pipe; |
| 1289 | |
| 1290 | return NULL; |
| 1291 | } |
| 1292 | |
| 1293 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1294 | * Determine where to splice to/from. |
| 1295 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1296 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1297 | struct file *out, loff_t __user *off_out, |
| 1298 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1299 | { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1300 | struct pipe_inode_info *ipipe; |
| 1301 | struct pipe_inode_info *opipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1302 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1303 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1304 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1305 | ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1306 | opipe = pipe_info(out->f_path.dentry->d_inode); |
| 1307 | |
| 1308 | if (ipipe && opipe) { |
| 1309 | if (off_in || off_out) |
| 1310 | return -ESPIPE; |
| 1311 | |
| 1312 | if (!(in->f_mode & FMODE_READ)) |
| 1313 | return -EBADF; |
| 1314 | |
| 1315 | if (!(out->f_mode & FMODE_WRITE)) |
| 1316 | return -EBADF; |
| 1317 | |
| 1318 | /* Splicing to self would be fun, but... */ |
| 1319 | if (ipipe == opipe) |
| 1320 | return -EINVAL; |
| 1321 | |
| 1322 | return splice_pipe_to_pipe(ipipe, opipe, len, flags); |
| 1323 | } |
| 1324 | |
| 1325 | if (ipipe) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1326 | if (off_in) |
| 1327 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1328 | if (off_out) { |
| 1329 | if (out->f_op->llseek == no_llseek) |
| 1330 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1331 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1332 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1333 | off = &offset; |
| 1334 | } else |
| 1335 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1336 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1337 | ret = do_splice_from(ipipe, out, off, len, flags); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1338 | |
| 1339 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1340 | ret = -EFAULT; |
| 1341 | |
| 1342 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1343 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1344 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1345 | if (opipe) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1346 | if (off_out) |
| 1347 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1348 | if (off_in) { |
| 1349 | if (in->f_op->llseek == no_llseek) |
| 1350 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1351 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1352 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1353 | off = &offset; |
| 1354 | } else |
| 1355 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1356 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1357 | ret = do_splice_to(in, off, opipe, len, flags); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1358 | |
| 1359 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1360 | ret = -EFAULT; |
| 1361 | |
| 1362 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1363 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1364 | |
| 1365 | return -EINVAL; |
| 1366 | } |
| 1367 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1368 | /* |
| 1369 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1370 | * partial_page structure, we can map several non-contiguous ranges into |
| 1371 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1372 | * Could easily be exported as a generic helper for other users, in which |
| 1373 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1374 | */ |
| 1375 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1376 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1377 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1378 | { |
| 1379 | int buffers = 0, error = 0; |
| 1380 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1381 | while (nr_vecs) { |
| 1382 | unsigned long off, npages; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1383 | struct iovec entry; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1384 | void __user *base; |
| 1385 | size_t len; |
| 1386 | int i; |
| 1387 | |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1388 | error = -EFAULT; |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1389 | if (copy_from_user(&entry, iov, sizeof(entry))) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1390 | break; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1391 | |
| 1392 | base = entry.iov_base; |
| 1393 | len = entry.iov_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1394 | |
| 1395 | /* |
| 1396 | * Sanity check this iovec. 0 read succeeds. |
| 1397 | */ |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1398 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1399 | if (unlikely(!len)) |
| 1400 | break; |
| 1401 | error = -EFAULT; |
Bastian Blank | 712a30e | 2008-02-10 16:47:57 +0200 | [diff] [blame] | 1402 | if (!access_ok(VERIFY_READ, base, len)) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1403 | break; |
| 1404 | |
| 1405 | /* |
| 1406 | * Get this base offset and number of pages, then map |
| 1407 | * in the user pages. |
| 1408 | */ |
| 1409 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1410 | |
| 1411 | /* |
| 1412 | * If asked for alignment, the offset must be zero and the |
| 1413 | * length a multiple of the PAGE_SIZE. |
| 1414 | */ |
| 1415 | error = -EINVAL; |
| 1416 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1417 | break; |
| 1418 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1419 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1420 | if (npages > PIPE_BUFFERS - buffers) |
| 1421 | npages = PIPE_BUFFERS - buffers; |
| 1422 | |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1423 | error = get_user_pages_fast((unsigned long)base, npages, |
| 1424 | 0, &pages[buffers]); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1425 | |
| 1426 | if (unlikely(error <= 0)) |
| 1427 | break; |
| 1428 | |
| 1429 | /* |
| 1430 | * Fill this contiguous range into the partial page map. |
| 1431 | */ |
| 1432 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1433 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1434 | |
| 1435 | partial[buffers].offset = off; |
| 1436 | partial[buffers].len = plen; |
| 1437 | |
| 1438 | off = 0; |
| 1439 | len -= plen; |
| 1440 | buffers++; |
| 1441 | } |
| 1442 | |
| 1443 | /* |
| 1444 | * We didn't complete this iov, stop here since it probably |
| 1445 | * means we have to move some of this into a pipe to |
| 1446 | * be able to continue. |
| 1447 | */ |
| 1448 | if (len) |
| 1449 | break; |
| 1450 | |
| 1451 | /* |
| 1452 | * Don't continue if we mapped fewer pages than we asked for, |
| 1453 | * or if we mapped the max number of pages that we have |
| 1454 | * room for. |
| 1455 | */ |
| 1456 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1457 | break; |
| 1458 | |
| 1459 | nr_vecs--; |
| 1460 | iov++; |
| 1461 | } |
| 1462 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1463 | if (buffers) |
| 1464 | return buffers; |
| 1465 | |
| 1466 | return error; |
| 1467 | } |
| 1468 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1469 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1470 | struct splice_desc *sd) |
| 1471 | { |
| 1472 | char *src; |
| 1473 | int ret; |
| 1474 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 1475 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1476 | if (unlikely(ret)) |
| 1477 | return ret; |
| 1478 | |
| 1479 | /* |
| 1480 | * See if we can use the atomic maps, by prefaulting in the |
| 1481 | * pages and doing an atomic copy |
| 1482 | */ |
| 1483 | if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { |
| 1484 | src = buf->ops->map(pipe, buf, 1); |
| 1485 | ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, |
| 1486 | sd->len); |
| 1487 | buf->ops->unmap(pipe, buf, src); |
| 1488 | if (!ret) { |
| 1489 | ret = sd->len; |
| 1490 | goto out; |
| 1491 | } |
| 1492 | } |
| 1493 | |
| 1494 | /* |
| 1495 | * No dice, use slow non-atomic map and copy |
| 1496 | */ |
| 1497 | src = buf->ops->map(pipe, buf, 0); |
| 1498 | |
| 1499 | ret = sd->len; |
| 1500 | if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) |
| 1501 | ret = -EFAULT; |
| 1502 | |
Jens Axboe | 6866bef | 2007-10-16 10:01:29 +0200 | [diff] [blame] | 1503 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1504 | out: |
| 1505 | if (ret > 0) |
| 1506 | sd->u.userptr += ret; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1507 | return ret; |
| 1508 | } |
| 1509 | |
| 1510 | /* |
| 1511 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1512 | * as a simple copy of the pipes pages to the user iov. |
| 1513 | */ |
| 1514 | static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, |
| 1515 | unsigned long nr_segs, unsigned int flags) |
| 1516 | { |
| 1517 | struct pipe_inode_info *pipe; |
| 1518 | struct splice_desc sd; |
| 1519 | ssize_t size; |
| 1520 | int error; |
| 1521 | long ret; |
| 1522 | |
| 1523 | pipe = pipe_info(file->f_path.dentry->d_inode); |
| 1524 | if (!pipe) |
| 1525 | return -EBADF; |
| 1526 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1527 | pipe_lock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1528 | |
| 1529 | error = ret = 0; |
| 1530 | while (nr_segs) { |
| 1531 | void __user *base; |
| 1532 | size_t len; |
| 1533 | |
| 1534 | /* |
| 1535 | * Get user address base and length for this iovec. |
| 1536 | */ |
| 1537 | error = get_user(base, &iov->iov_base); |
| 1538 | if (unlikely(error)) |
| 1539 | break; |
| 1540 | error = get_user(len, &iov->iov_len); |
| 1541 | if (unlikely(error)) |
| 1542 | break; |
| 1543 | |
| 1544 | /* |
| 1545 | * Sanity check this iovec. 0 read succeeds. |
| 1546 | */ |
| 1547 | if (unlikely(!len)) |
| 1548 | break; |
| 1549 | if (unlikely(!base)) { |
| 1550 | error = -EFAULT; |
| 1551 | break; |
| 1552 | } |
| 1553 | |
Jens Axboe | 8811930 | 2008-02-08 08:49:14 -0800 | [diff] [blame] | 1554 | if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { |
| 1555 | error = -EFAULT; |
| 1556 | break; |
| 1557 | } |
| 1558 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1559 | sd.len = 0; |
| 1560 | sd.total_len = len; |
| 1561 | sd.flags = flags; |
| 1562 | sd.u.userptr = base; |
| 1563 | sd.pos = 0; |
| 1564 | |
| 1565 | size = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1566 | if (size < 0) { |
| 1567 | if (!ret) |
| 1568 | ret = size; |
| 1569 | |
| 1570 | break; |
| 1571 | } |
| 1572 | |
| 1573 | ret += size; |
| 1574 | |
| 1575 | if (size < len) |
| 1576 | break; |
| 1577 | |
| 1578 | nr_segs--; |
| 1579 | iov++; |
| 1580 | } |
| 1581 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1582 | pipe_unlock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1583 | |
| 1584 | if (!ret) |
| 1585 | ret = error; |
| 1586 | |
| 1587 | return ret; |
| 1588 | } |
| 1589 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1590 | /* |
| 1591 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1592 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1593 | * to file). In both cases the output is a pipe, naturally. |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1594 | */ |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1595 | static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, |
| 1596 | unsigned long nr_segs, unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1597 | { |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1598 | struct pipe_inode_info *pipe; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1599 | struct page *pages[PIPE_BUFFERS]; |
| 1600 | struct partial_page partial[PIPE_BUFFERS]; |
| 1601 | struct splice_pipe_desc spd = { |
| 1602 | .pages = pages, |
| 1603 | .partial = partial, |
| 1604 | .flags = flags, |
| 1605 | .ops = &user_page_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 1606 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1607 | }; |
| 1608 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1609 | pipe = pipe_info(file->f_path.dentry->d_inode); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1610 | if (!pipe) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1611 | return -EBADF; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1612 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1613 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1614 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1615 | if (spd.nr_pages <= 0) |
| 1616 | return spd.nr_pages; |
| 1617 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1618 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1619 | } |
| 1620 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1621 | /* |
| 1622 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1623 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1624 | * operation that can be supported without any funky alignment restrictions |
| 1625 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1626 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1627 | * solutions for that: |
| 1628 | * |
| 1629 | * - memcpy() the data internally, at which point we might as well just |
| 1630 | * do a regular read() on the buffer anyway. |
| 1631 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1632 | * has restriction limitations on both ends of the pipe). |
| 1633 | * |
| 1634 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1635 | * |
| 1636 | */ |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1637 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, |
| 1638 | unsigned long, nr_segs, unsigned int, flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1639 | { |
| 1640 | struct file *file; |
| 1641 | long error; |
| 1642 | int fput; |
| 1643 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1644 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1645 | return -EINVAL; |
| 1646 | else if (unlikely(!nr_segs)) |
| 1647 | return 0; |
| 1648 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1649 | error = -EBADF; |
| 1650 | file = fget_light(fd, &fput); |
| 1651 | if (file) { |
| 1652 | if (file->f_mode & FMODE_WRITE) |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1653 | error = vmsplice_to_pipe(file, iov, nr_segs, flags); |
| 1654 | else if (file->f_mode & FMODE_READ) |
| 1655 | error = vmsplice_to_user(file, iov, nr_segs, flags); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1656 | |
| 1657 | fput_light(file, fput); |
| 1658 | } |
| 1659 | |
| 1660 | return error; |
| 1661 | } |
| 1662 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1663 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
| 1664 | int, fd_out, loff_t __user *, off_out, |
| 1665 | size_t, len, unsigned int, flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1666 | { |
| 1667 | long error; |
| 1668 | struct file *in, *out; |
| 1669 | int fput_in, fput_out; |
| 1670 | |
| 1671 | if (unlikely(!len)) |
| 1672 | return 0; |
| 1673 | |
| 1674 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1675 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1676 | if (in) { |
| 1677 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1678 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1679 | if (out) { |
| 1680 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1681 | error = do_splice(in, off_in, |
| 1682 | out, off_out, |
| 1683 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1684 | fput_light(out, fput_out); |
| 1685 | } |
| 1686 | } |
| 1687 | |
| 1688 | fput_light(in, fput_in); |
| 1689 | } |
| 1690 | |
| 1691 | return error; |
| 1692 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1693 | |
| 1694 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1695 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1696 | * return an appropriate error. |
| 1697 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1698 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1699 | { |
| 1700 | int ret; |
| 1701 | |
| 1702 | /* |
| 1703 | * Check ->nrbufs without the inode lock first. This function |
| 1704 | * is speculative anyways, so missing one is ok. |
| 1705 | */ |
| 1706 | if (pipe->nrbufs) |
| 1707 | return 0; |
| 1708 | |
| 1709 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1710 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1711 | |
| 1712 | while (!pipe->nrbufs) { |
| 1713 | if (signal_pending(current)) { |
| 1714 | ret = -ERESTARTSYS; |
| 1715 | break; |
| 1716 | } |
| 1717 | if (!pipe->writers) |
| 1718 | break; |
| 1719 | if (!pipe->waiting_writers) { |
| 1720 | if (flags & SPLICE_F_NONBLOCK) { |
| 1721 | ret = -EAGAIN; |
| 1722 | break; |
| 1723 | } |
| 1724 | } |
| 1725 | pipe_wait(pipe); |
| 1726 | } |
| 1727 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1728 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1729 | return ret; |
| 1730 | } |
| 1731 | |
| 1732 | /* |
| 1733 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1734 | * return an appropriate error. |
| 1735 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1736 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1737 | { |
| 1738 | int ret; |
| 1739 | |
| 1740 | /* |
| 1741 | * Check ->nrbufs without the inode lock first. This function |
| 1742 | * is speculative anyways, so missing one is ok. |
| 1743 | */ |
| 1744 | if (pipe->nrbufs < PIPE_BUFFERS) |
| 1745 | return 0; |
| 1746 | |
| 1747 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1748 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1749 | |
| 1750 | while (pipe->nrbufs >= PIPE_BUFFERS) { |
| 1751 | if (!pipe->readers) { |
| 1752 | send_sig(SIGPIPE, current, 0); |
| 1753 | ret = -EPIPE; |
| 1754 | break; |
| 1755 | } |
| 1756 | if (flags & SPLICE_F_NONBLOCK) { |
| 1757 | ret = -EAGAIN; |
| 1758 | break; |
| 1759 | } |
| 1760 | if (signal_pending(current)) { |
| 1761 | ret = -ERESTARTSYS; |
| 1762 | break; |
| 1763 | } |
| 1764 | pipe->waiting_writers++; |
| 1765 | pipe_wait(pipe); |
| 1766 | pipe->waiting_writers--; |
| 1767 | } |
| 1768 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1769 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1770 | return ret; |
| 1771 | } |
| 1772 | |
| 1773 | /* |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1774 | * Splice contents of ipipe to opipe. |
| 1775 | */ |
| 1776 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1777 | struct pipe_inode_info *opipe, |
| 1778 | size_t len, unsigned int flags) |
| 1779 | { |
| 1780 | struct pipe_buffer *ibuf, *obuf; |
| 1781 | int ret = 0, nbuf; |
| 1782 | bool input_wakeup = false; |
| 1783 | |
| 1784 | |
| 1785 | retry: |
| 1786 | ret = ipipe_prep(ipipe, flags); |
| 1787 | if (ret) |
| 1788 | return ret; |
| 1789 | |
| 1790 | ret = opipe_prep(opipe, flags); |
| 1791 | if (ret) |
| 1792 | return ret; |
| 1793 | |
| 1794 | /* |
| 1795 | * Potential ABBA deadlock, work around it by ordering lock |
| 1796 | * grabbing by pipe info address. Otherwise two different processes |
| 1797 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1798 | */ |
| 1799 | pipe_double_lock(ipipe, opipe); |
| 1800 | |
| 1801 | do { |
| 1802 | if (!opipe->readers) { |
| 1803 | send_sig(SIGPIPE, current, 0); |
| 1804 | if (!ret) |
| 1805 | ret = -EPIPE; |
| 1806 | break; |
| 1807 | } |
| 1808 | |
| 1809 | if (!ipipe->nrbufs && !ipipe->writers) |
| 1810 | break; |
| 1811 | |
| 1812 | /* |
| 1813 | * Cannot make any progress, because either the input |
| 1814 | * pipe is empty or the output pipe is full. |
| 1815 | */ |
| 1816 | if (!ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) { |
| 1817 | /* Already processed some buffers, break */ |
| 1818 | if (ret) |
| 1819 | break; |
| 1820 | |
| 1821 | if (flags & SPLICE_F_NONBLOCK) { |
| 1822 | ret = -EAGAIN; |
| 1823 | break; |
| 1824 | } |
| 1825 | |
| 1826 | /* |
| 1827 | * We raced with another reader/writer and haven't |
| 1828 | * managed to process any buffers. A zero return |
| 1829 | * value means EOF, so retry instead. |
| 1830 | */ |
| 1831 | pipe_unlock(ipipe); |
| 1832 | pipe_unlock(opipe); |
| 1833 | goto retry; |
| 1834 | } |
| 1835 | |
| 1836 | ibuf = ipipe->bufs + ipipe->curbuf; |
| 1837 | nbuf = (opipe->curbuf + opipe->nrbufs) % PIPE_BUFFERS; |
| 1838 | obuf = opipe->bufs + nbuf; |
| 1839 | |
| 1840 | if (len >= ibuf->len) { |
| 1841 | /* |
| 1842 | * Simply move the whole buffer from ipipe to opipe |
| 1843 | */ |
| 1844 | *obuf = *ibuf; |
| 1845 | ibuf->ops = NULL; |
| 1846 | opipe->nrbufs++; |
| 1847 | ipipe->curbuf = (ipipe->curbuf + 1) % PIPE_BUFFERS; |
| 1848 | ipipe->nrbufs--; |
| 1849 | input_wakeup = true; |
| 1850 | } else { |
| 1851 | /* |
| 1852 | * Get a reference to this pipe buffer, |
| 1853 | * so we can copy the contents over. |
| 1854 | */ |
| 1855 | ibuf->ops->get(ipipe, ibuf); |
| 1856 | *obuf = *ibuf; |
| 1857 | |
| 1858 | /* |
| 1859 | * Don't inherit the gift flag, we need to |
| 1860 | * prevent multiple steals of this page. |
| 1861 | */ |
| 1862 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1863 | |
| 1864 | obuf->len = len; |
| 1865 | opipe->nrbufs++; |
| 1866 | ibuf->offset += obuf->len; |
| 1867 | ibuf->len -= obuf->len; |
| 1868 | } |
| 1869 | ret += obuf->len; |
| 1870 | len -= obuf->len; |
| 1871 | } while (len); |
| 1872 | |
| 1873 | pipe_unlock(ipipe); |
| 1874 | pipe_unlock(opipe); |
| 1875 | |
| 1876 | /* |
| 1877 | * If we put data in the output pipe, wakeup any potential readers. |
| 1878 | */ |
| 1879 | if (ret > 0) { |
| 1880 | smp_mb(); |
| 1881 | if (waitqueue_active(&opipe->wait)) |
| 1882 | wake_up_interruptible(&opipe->wait); |
| 1883 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1884 | } |
| 1885 | if (input_wakeup) |
| 1886 | wakeup_pipe_writers(ipipe); |
| 1887 | |
| 1888 | return ret; |
| 1889 | } |
| 1890 | |
| 1891 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1892 | * Link contents of ipipe to opipe. |
| 1893 | */ |
| 1894 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1895 | struct pipe_inode_info *opipe, |
| 1896 | size_t len, unsigned int flags) |
| 1897 | { |
| 1898 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1899 | int ret = 0, i = 0, nbuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1900 | |
| 1901 | /* |
| 1902 | * Potential ABBA deadlock, work around it by ordering lock |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1903 | * grabbing by pipe info address. Otherwise two different processes |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1904 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1905 | */ |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1906 | pipe_double_lock(ipipe, opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1907 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1908 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1909 | if (!opipe->readers) { |
| 1910 | send_sig(SIGPIPE, current, 0); |
| 1911 | if (!ret) |
| 1912 | ret = -EPIPE; |
| 1913 | break; |
| 1914 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1915 | |
| 1916 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1917 | * If we have iterated all input buffers or ran out of |
| 1918 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1919 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1920 | if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1921 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1922 | |
| 1923 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1924 | nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1925 | |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1926 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1927 | * Get a reference to this pipe buffer, |
| 1928 | * so we can copy the contents over. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1929 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1930 | ibuf->ops->get(ipipe, 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 | obuf = opipe->bufs + nbuf; |
| 1933 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1934 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1935 | /* |
| 1936 | * Don't inherit the gift flag, we need to |
| 1937 | * prevent multiple steals of this page. |
| 1938 | */ |
| 1939 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1940 | |
| 1941 | if (obuf->len > len) |
| 1942 | obuf->len = len; |
| 1943 | |
| 1944 | opipe->nrbufs++; |
| 1945 | ret += obuf->len; |
| 1946 | len -= obuf->len; |
| 1947 | i++; |
| 1948 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1949 | |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1950 | /* |
| 1951 | * return EAGAIN if we have the potential of some data in the |
| 1952 | * future, otherwise just return 0 |
| 1953 | */ |
| 1954 | if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) |
| 1955 | ret = -EAGAIN; |
| 1956 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1957 | pipe_unlock(ipipe); |
| 1958 | pipe_unlock(opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1959 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1960 | /* |
| 1961 | * If we put data in the output pipe, wakeup any potential readers. |
| 1962 | */ |
| 1963 | if (ret > 0) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1964 | smp_mb(); |
| 1965 | if (waitqueue_active(&opipe->wait)) |
| 1966 | wake_up_interruptible(&opipe->wait); |
| 1967 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1968 | } |
| 1969 | |
| 1970 | return ret; |
| 1971 | } |
| 1972 | |
| 1973 | /* |
| 1974 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1975 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1976 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1977 | * applicable one is SPLICE_F_NONBLOCK. |
| 1978 | */ |
| 1979 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1980 | unsigned int flags) |
| 1981 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1982 | struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1983 | struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1984 | int ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1985 | |
| 1986 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1987 | * Duplicate the contents of ipipe to opipe without actually |
| 1988 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1989 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1990 | if (ipipe && opipe && ipipe != opipe) { |
| 1991 | /* |
| 1992 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1993 | * ordering doesn't really matter. |
| 1994 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1995 | ret = ipipe_prep(ipipe, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1996 | if (!ret) { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1997 | ret = opipe_prep(opipe, flags); |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1998 | if (!ret) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1999 | ret = link_pipe(ipipe, opipe, len, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 2000 | } |
| 2001 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 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 | { |
| 2008 | struct file *in; |
| 2009 | int error, fput_in; |
| 2010 | |
| 2011 | if (unlikely(!len)) |
| 2012 | return 0; |
| 2013 | |
| 2014 | error = -EBADF; |
| 2015 | in = fget_light(fdin, &fput_in); |
| 2016 | if (in) { |
| 2017 | if (in->f_mode & FMODE_READ) { |
| 2018 | int fput_out; |
| 2019 | struct file *out = fget_light(fdout, &fput_out); |
| 2020 | |
| 2021 | if (out) { |
| 2022 | if (out->f_mode & FMODE_WRITE) |
| 2023 | error = do_tee(in, out, len, flags); |
| 2024 | fput_light(out, fput_out); |
| 2025 | } |
| 2026 | } |
| 2027 | fput_light(in, fput_in); |
| 2028 | } |
| 2029 | |
| 2030 | return error; |
| 2031 | } |