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 | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de> |
| 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> |
| 23 | #include <linux/pipe_fs_i.h> |
| 24 | #include <linux/mm_inline.h> |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 25 | #include <linux/swap.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 26 | #include <linux/writeback.h> |
| 27 | #include <linux/buffer_head.h> |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 28 | #include <linux/module.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 29 | #include <linux/syscalls.h> |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 30 | #include <linux/uio.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 31 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 32 | struct partial_page { |
| 33 | unsigned int offset; |
| 34 | unsigned int len; |
| 35 | }; |
| 36 | |
| 37 | /* |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 38 | * Passed to splice_to_pipe |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 39 | */ |
| 40 | struct splice_pipe_desc { |
| 41 | struct page **pages; /* page map */ |
| 42 | struct partial_page *partial; /* pages[] may not be contig */ |
| 43 | int nr_pages; /* number of pages in map */ |
| 44 | unsigned int flags; /* splice flags */ |
| 45 | struct pipe_buf_operations *ops;/* ops associated with output pipe */ |
| 46 | }; |
| 47 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 48 | /* |
| 49 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 50 | * a vm helper function, it's already simplified quite a bit by the |
| 51 | * addition of remove_mapping(). If success is returned, the caller may |
| 52 | * attempt to reuse this page for another destination. |
| 53 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 54 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, |
| 55 | struct pipe_buffer *buf) |
| 56 | { |
| 57 | struct page *page = buf->page; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 58 | struct address_space *mapping = page_mapping(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 59 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 60 | lock_page(page); |
| 61 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 62 | WARN_ON(!PageUptodate(page)); |
| 63 | |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 64 | /* |
| 65 | * At least for ext2 with nobh option, we need to wait on writeback |
| 66 | * completing on this page, since we'll remove it from the pagecache. |
| 67 | * Otherwise truncate wont wait on the page, allowing the disk |
| 68 | * blocks to be reused by someone else before we actually wrote our |
| 69 | * data to them. fs corruption ensues. |
| 70 | */ |
| 71 | wait_on_page_writeback(page); |
| 72 | |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 73 | if (PagePrivate(page)) |
| 74 | try_to_release_page(page, mapping_gfp_mask(mapping)); |
| 75 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 76 | if (!remove_mapping(mapping, page)) { |
| 77 | unlock_page(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 78 | return 1; |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 79 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 80 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 81 | return 0; |
| 82 | } |
| 83 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 84 | static void page_cache_pipe_buf_release(struct pipe_inode_info *info, |
| 85 | struct pipe_buffer *buf) |
| 86 | { |
| 87 | page_cache_release(buf->page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 88 | } |
| 89 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 90 | static int page_cache_pipe_buf_pin(struct pipe_inode_info *info, |
| 91 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 92 | { |
| 93 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 94 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 95 | |
| 96 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 97 | lock_page(page); |
| 98 | |
| 99 | /* |
| 100 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 101 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 102 | */ |
| 103 | if (!page->mapping) { |
| 104 | err = -ENODATA; |
| 105 | goto error; |
| 106 | } |
| 107 | |
| 108 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 109 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 110 | */ |
| 111 | if (!PageUptodate(page)) { |
| 112 | err = -EIO; |
| 113 | goto error; |
| 114 | } |
| 115 | |
| 116 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 117 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 118 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 119 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 120 | } |
| 121 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 122 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 123 | error: |
| 124 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 125 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 126 | } |
| 127 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 128 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { |
| 129 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 130 | .map = generic_pipe_buf_map, |
| 131 | .unmap = generic_pipe_buf_unmap, |
| 132 | .pin = page_cache_pipe_buf_pin, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 133 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 134 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 135 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 136 | }; |
| 137 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 138 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 139 | struct pipe_buffer *buf) |
| 140 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 141 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 142 | return 1; |
| 143 | |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame^] | 144 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 145 | } |
| 146 | |
| 147 | static struct pipe_buf_operations user_page_pipe_buf_ops = { |
| 148 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 149 | .map = generic_pipe_buf_map, |
| 150 | .unmap = generic_pipe_buf_unmap, |
| 151 | .pin = generic_pipe_buf_pin, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 152 | .release = page_cache_pipe_buf_release, |
| 153 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 154 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 155 | }; |
| 156 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 157 | /* |
| 158 | * Pipe output worker. This sets up our pipe format with the page cache |
| 159 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). |
| 160 | */ |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 161 | static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 162 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 163 | { |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 164 | int ret, do_wakeup, page_nr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 165 | |
| 166 | ret = 0; |
| 167 | do_wakeup = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 168 | page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 169 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 170 | if (pipe->inode) |
| 171 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 172 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 173 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 174 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 175 | send_sig(SIGPIPE, current, 0); |
| 176 | if (!ret) |
| 177 | ret = -EPIPE; |
| 178 | break; |
| 179 | } |
| 180 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 181 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 182 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 183 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 184 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 185 | buf->page = spd->pages[page_nr]; |
| 186 | buf->offset = spd->partial[page_nr].offset; |
| 187 | buf->len = spd->partial[page_nr].len; |
| 188 | buf->ops = spd->ops; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 189 | if (spd->flags & SPLICE_F_GIFT) |
| 190 | buf->flags |= PIPE_BUF_FLAG_GIFT; |
| 191 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 192 | pipe->nrbufs++; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 193 | page_nr++; |
| 194 | ret += buf->len; |
| 195 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 196 | if (pipe->inode) |
| 197 | do_wakeup = 1; |
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 | if (!--spd->nr_pages) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 200 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 201 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 202 | continue; |
| 203 | |
| 204 | break; |
| 205 | } |
| 206 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 207 | if (spd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 208 | if (!ret) |
| 209 | ret = -EAGAIN; |
| 210 | break; |
| 211 | } |
| 212 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 213 | if (signal_pending(current)) { |
| 214 | if (!ret) |
| 215 | ret = -ERESTARTSYS; |
| 216 | break; |
| 217 | } |
| 218 | |
| 219 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 220 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 221 | if (waitqueue_active(&pipe->wait)) |
| 222 | wake_up_interruptible_sync(&pipe->wait); |
| 223 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 224 | do_wakeup = 0; |
| 225 | } |
| 226 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 227 | pipe->waiting_writers++; |
| 228 | pipe_wait(pipe); |
| 229 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 230 | } |
| 231 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 232 | if (pipe->inode) |
| 233 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 234 | |
| 235 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 236 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 237 | if (waitqueue_active(&pipe->wait)) |
| 238 | wake_up_interruptible(&pipe->wait); |
| 239 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 240 | } |
| 241 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 242 | while (page_nr < spd->nr_pages) |
| 243 | page_cache_release(spd->pages[page_nr++]); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 244 | |
| 245 | return ret; |
| 246 | } |
| 247 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 248 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 249 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 250 | struct pipe_inode_info *pipe, size_t len, |
| 251 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 252 | { |
| 253 | struct address_space *mapping = in->f_mapping; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 254 | unsigned int loff, nr_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 255 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 256 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 257 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 258 | pgoff_t index, end_index; |
| 259 | loff_t isize; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 260 | size_t total_len; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 261 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 262 | struct splice_pipe_desc spd = { |
| 263 | .pages = pages, |
| 264 | .partial = partial, |
| 265 | .flags = flags, |
| 266 | .ops = &page_cache_pipe_buf_ops, |
| 267 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 268 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 269 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 270 | loff = *ppos & ~PAGE_CACHE_MASK; |
| 271 | nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 272 | |
| 273 | if (nr_pages > PIPE_BUFFERS) |
| 274 | nr_pages = PIPE_BUFFERS; |
| 275 | |
| 276 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 277 | * Initiate read-ahead on this page range. however, don't call into |
Jens Axboe | 0b749ce | 2006-04-10 09:05:04 +0200 | [diff] [blame] | 278 | * read-ahead if this is a non-zero offset (we are likely doing small |
| 279 | * chunk splice and the page is already there) for a single page. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 280 | */ |
Jens Axboe | eb645a2 | 2006-04-27 08:44:27 +0200 | [diff] [blame] | 281 | if (!loff || nr_pages > 1) |
| 282 | page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 283 | |
| 284 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 285 | * Now fill in the holes: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 286 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 287 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 288 | total_len = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 289 | |
| 290 | /* |
| 291 | * Lookup the (hopefully) full range of pages we need. |
| 292 | */ |
| 293 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
| 294 | |
| 295 | /* |
| 296 | * If find_get_pages_contig() returned fewer pages than we needed, |
| 297 | * allocate the rest. |
| 298 | */ |
| 299 | index += spd.nr_pages; |
| 300 | while (spd.nr_pages < nr_pages) { |
| 301 | /* |
| 302 | * Page could be there, find_get_pages_contig() breaks on |
| 303 | * the first hole. |
| 304 | */ |
| 305 | page = find_get_page(mapping, index); |
| 306 | if (!page) { |
| 307 | /* |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 308 | * Make sure the read-ahead engine is notified |
| 309 | * about this failure. |
| 310 | */ |
| 311 | handle_ra_miss(mapping, &in->f_ra, index); |
| 312 | |
| 313 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 314 | * page didn't exist, allocate one. |
| 315 | */ |
| 316 | page = page_cache_alloc_cold(mapping); |
| 317 | if (!page) |
| 318 | break; |
| 319 | |
| 320 | error = add_to_page_cache_lru(page, mapping, index, |
| 321 | mapping_gfp_mask(mapping)); |
| 322 | if (unlikely(error)) { |
| 323 | page_cache_release(page); |
| 324 | break; |
| 325 | } |
| 326 | /* |
| 327 | * add_to_page_cache() locks the page, unlock it |
| 328 | * to avoid convoluting the logic below even more. |
| 329 | */ |
| 330 | unlock_page(page); |
| 331 | } |
| 332 | |
| 333 | pages[spd.nr_pages++] = page; |
| 334 | index++; |
| 335 | } |
| 336 | |
| 337 | /* |
| 338 | * Now loop over the map and see if we need to start IO on any |
| 339 | * pages, fill in the partial map, etc. |
| 340 | */ |
| 341 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 342 | nr_pages = spd.nr_pages; |
| 343 | spd.nr_pages = 0; |
| 344 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 345 | unsigned int this_len; |
| 346 | |
| 347 | if (!len) |
| 348 | break; |
| 349 | |
| 350 | /* |
| 351 | * this_len is the max we'll use from this page |
| 352 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 353 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 354 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 355 | |
| 356 | /* |
| 357 | * If the page isn't uptodate, we may need to start io on it |
| 358 | */ |
| 359 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 360 | /* |
| 361 | * If in nonblock mode then dont block on waiting |
| 362 | * for an in-flight io page |
| 363 | */ |
| 364 | if (flags & SPLICE_F_NONBLOCK) |
| 365 | break; |
| 366 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 367 | lock_page(page); |
| 368 | |
| 369 | /* |
| 370 | * page was truncated, stop here. if this isn't the |
| 371 | * first page, we'll just complete what we already |
| 372 | * added |
| 373 | */ |
| 374 | if (!page->mapping) { |
| 375 | unlock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 376 | break; |
| 377 | } |
| 378 | /* |
| 379 | * page was already under io and is now done, great |
| 380 | */ |
| 381 | if (PageUptodate(page)) { |
| 382 | unlock_page(page); |
| 383 | goto fill_it; |
| 384 | } |
| 385 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 386 | /* |
| 387 | * need to read in the page |
| 388 | */ |
| 389 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 390 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 391 | /* |
| 392 | * We really should re-lookup the page here, |
| 393 | * but it complicates things a lot. Instead |
| 394 | * lets just do what we already stored, and |
| 395 | * we'll get it the next time we are called. |
| 396 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 397 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 398 | error = 0; |
| 399 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 400 | break; |
| 401 | } |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 402 | |
| 403 | /* |
| 404 | * i_size must be checked after ->readpage(). |
| 405 | */ |
| 406 | isize = i_size_read(mapping->host); |
| 407 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 408 | if (unlikely(!isize || index > end_index)) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 409 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 410 | |
| 411 | /* |
| 412 | * if this is the last page, see if we need to shrink |
| 413 | * the length and stop |
| 414 | */ |
| 415 | if (end_index == index) { |
| 416 | loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 417 | if (total_len + loff > isize) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 418 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 419 | /* |
| 420 | * force quit after adding this page |
| 421 | */ |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 422 | len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 423 | this_len = min(this_len, loff); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 424 | loff = 0; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 425 | } |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 426 | } |
| 427 | fill_it: |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 428 | partial[page_nr].offset = loff; |
| 429 | partial[page_nr].len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 430 | len -= this_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 431 | total_len += this_len; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 432 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 433 | spd.nr_pages++; |
| 434 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 435 | } |
| 436 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 437 | /* |
| 438 | * Release any pages at the end, if we quit early. 'i' is how far |
| 439 | * we got, 'nr_pages' is how many pages are in the map. |
| 440 | */ |
| 441 | while (page_nr < nr_pages) |
| 442 | page_cache_release(pages[page_nr++]); |
| 443 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 444 | if (spd.nr_pages) |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 445 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 446 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 447 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 448 | } |
| 449 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 450 | /** |
| 451 | * generic_file_splice_read - splice data from file to a pipe |
| 452 | * @in: file to splice from |
| 453 | * @pipe: pipe to splice to |
| 454 | * @len: number of bytes to splice |
| 455 | * @flags: splice modifier flags |
| 456 | * |
| 457 | * Will read pages from given file and fill them into a pipe. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 458 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 459 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 460 | struct pipe_inode_info *pipe, size_t len, |
| 461 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 462 | { |
| 463 | ssize_t spliced; |
| 464 | int ret; |
| 465 | |
| 466 | ret = 0; |
| 467 | spliced = 0; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 468 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 469 | while (len) { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 470 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 471 | |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 472 | if (ret < 0) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 473 | break; |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 474 | else if (!ret) { |
| 475 | if (spliced) |
| 476 | break; |
| 477 | if (flags & SPLICE_F_NONBLOCK) { |
| 478 | ret = -EAGAIN; |
| 479 | break; |
| 480 | } |
| 481 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 482 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 483 | *ppos += ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 484 | len -= ret; |
| 485 | spliced += ret; |
| 486 | } |
| 487 | |
| 488 | if (spliced) |
| 489 | return spliced; |
| 490 | |
| 491 | return ret; |
| 492 | } |
| 493 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 494 | EXPORT_SYMBOL(generic_file_splice_read); |
| 495 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 496 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 497 | * 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] | 498 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 499 | */ |
| 500 | static int pipe_to_sendpage(struct pipe_inode_info *info, |
| 501 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 502 | { |
| 503 | struct file *file = sd->file; |
| 504 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 505 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 506 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 507 | ret = buf->ops->pin(info, buf); |
| 508 | if (!ret) { |
| 509 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 510 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 511 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 512 | sd->len, &pos, more); |
| 513 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 514 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 515 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 516 | } |
| 517 | |
| 518 | /* |
| 519 | * This is a little more tricky than the file -> pipe splicing. There are |
| 520 | * basically three cases: |
| 521 | * |
| 522 | * - Destination page already exists in the address space and there |
| 523 | * are users of it. For that case we have no other option that |
| 524 | * copying the data. Tough luck. |
| 525 | * - Destination page already exists in the address space, but there |
| 526 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 527 | * through to last case. |
| 528 | * - Destination page does not exist, we can add the pipe page to |
| 529 | * the page cache and avoid the copy. |
| 530 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 531 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 532 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 533 | * file address space page cache. This is possible if no one else has |
| 534 | * the pipe page referenced outside of the pipe and page cache. If |
| 535 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 536 | * 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] | 537 | */ |
| 538 | static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, |
| 539 | struct splice_desc *sd) |
| 540 | { |
| 541 | struct file *file = sd->file; |
| 542 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 543 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 544 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 545 | struct page *page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 546 | pgoff_t index; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 547 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 548 | |
| 549 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 550 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 551 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 552 | ret = buf->ops->pin(info, buf); |
| 553 | if (unlikely(ret)) |
| 554 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 555 | |
| 556 | index = sd->pos >> PAGE_CACHE_SHIFT; |
| 557 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 558 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 559 | this_len = sd->len; |
| 560 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 561 | this_len = PAGE_CACHE_SIZE - offset; |
| 562 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 563 | /* |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 564 | * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full |
| 565 | * page. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 566 | */ |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 567 | if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) { |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 568 | /* |
| 569 | * If steal succeeds, buf->page is now pruned from the vm |
Jens Axboe | a893b99 | 2006-05-02 15:03:27 +0200 | [diff] [blame] | 570 | * side (page cache) and we can reuse it. The page will also |
| 571 | * be locked on successful return. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 572 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 573 | if (buf->ops->steal(info, buf)) |
| 574 | goto find_page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 575 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 576 | page = buf->page; |
Jens Axboe | a893b99 | 2006-05-02 15:03:27 +0200 | [diff] [blame] | 577 | page_cache_get(page); |
| 578 | |
| 579 | /* |
| 580 | * page must be on the LRU for adding to the pagecache. |
| 581 | * Check this without grabbing the zone lock, if it isn't |
| 582 | * the do grab the zone lock, recheck, and add if necessary. |
| 583 | */ |
| 584 | if (!PageLRU(page)) { |
| 585 | struct zone *zone = page_zone(page); |
| 586 | |
| 587 | spin_lock_irq(&zone->lru_lock); |
| 588 | if (!PageLRU(page)) { |
| 589 | SetPageLRU(page); |
| 590 | add_page_to_inactive_list(zone, page); |
| 591 | } |
| 592 | spin_unlock_irq(&zone->lru_lock); |
| 593 | } |
| 594 | |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 595 | if (add_to_page_cache(page, mapping, index, gfp_mask)) { |
Jens Axboe | a893b99 | 2006-05-02 15:03:27 +0200 | [diff] [blame] | 596 | page_cache_release(page); |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 597 | unlock_page(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 598 | goto find_page; |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 599 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 600 | } else { |
| 601 | find_page: |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 602 | page = find_lock_page(mapping, index); |
| 603 | if (!page) { |
| 604 | ret = -ENOMEM; |
| 605 | page = page_cache_alloc_cold(mapping); |
| 606 | if (unlikely(!page)) |
| 607 | goto out_nomem; |
| 608 | |
| 609 | /* |
| 610 | * This will also lock the page |
| 611 | */ |
| 612 | ret = add_to_page_cache_lru(page, mapping, index, |
| 613 | gfp_mask); |
| 614 | if (unlikely(ret)) |
| 615 | goto out; |
| 616 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 617 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 618 | /* |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 619 | * We get here with the page locked. If the page is also |
| 620 | * uptodate, we don't need to do more. If it isn't, we |
| 621 | * may need to bring it in if we are not going to overwrite |
| 622 | * the full page. |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 623 | */ |
| 624 | if (!PageUptodate(page)) { |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 625 | if (this_len < PAGE_CACHE_SIZE) { |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 626 | ret = mapping->a_ops->readpage(file, page); |
| 627 | if (unlikely(ret)) |
| 628 | goto out; |
| 629 | |
| 630 | lock_page(page); |
| 631 | |
| 632 | if (!PageUptodate(page)) { |
| 633 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 634 | * Page got invalidated, repeat. |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 635 | */ |
| 636 | if (!page->mapping) { |
| 637 | unlock_page(page); |
| 638 | page_cache_release(page); |
| 639 | goto find_page; |
| 640 | } |
| 641 | ret = -EIO; |
| 642 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 643 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 644 | } else |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 645 | SetPageUptodate(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 646 | } |
| 647 | } |
| 648 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 649 | ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 650 | if (ret == AOP_TRUNCATED_PAGE) { |
| 651 | page_cache_release(page); |
| 652 | goto find_page; |
| 653 | } else if (ret) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 654 | goto out; |
| 655 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 656 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 657 | /* |
| 658 | * Careful, ->map() uses KM_USER0! |
| 659 | */ |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 660 | char *src = buf->ops->map(info, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 661 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 662 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 663 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 664 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 665 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 666 | buf->ops->unmap(info, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 667 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 668 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 669 | ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 670 | if (!ret) { |
| 671 | /* |
| 672 | * Return the number of bytes written and mark page as |
| 673 | * accessed, we are now done! |
| 674 | */ |
| 675 | ret = this_len; |
| 676 | mark_page_accessed(page); |
| 677 | balance_dirty_pages_ratelimited(mapping); |
| 678 | } else if (ret == AOP_TRUNCATED_PAGE) { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 679 | page_cache_release(page); |
| 680 | goto find_page; |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 681 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 682 | out: |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 683 | page_cache_release(page); |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 684 | unlock_page(page); |
Dave Jones | 9aefe43 | 2006-04-10 09:02:40 +0200 | [diff] [blame] | 685 | out_nomem: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 686 | return ret; |
| 687 | } |
| 688 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 689 | /* |
| 690 | * Pipe input worker. Most of this logic works like a regular pipe, the |
| 691 | * key here is the 'actor' worker passed in that actually moves the data |
| 692 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. |
| 693 | */ |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 694 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 695 | loff_t *ppos, size_t len, unsigned int flags, |
| 696 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 697 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 698 | int ret, do_wakeup, err; |
| 699 | struct splice_desc sd; |
| 700 | |
| 701 | ret = 0; |
| 702 | do_wakeup = 0; |
| 703 | |
| 704 | sd.total_len = len; |
| 705 | sd.flags = flags; |
| 706 | sd.file = out; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 707 | sd.pos = *ppos; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 708 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 709 | if (pipe->inode) |
| 710 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 711 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 712 | for (;;) { |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 713 | if (pipe->nrbufs) { |
| 714 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 715 | struct pipe_buf_operations *ops = buf->ops; |
| 716 | |
| 717 | sd.len = buf->len; |
| 718 | if (sd.len > sd.total_len) |
| 719 | sd.len = sd.total_len; |
| 720 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 721 | err = actor(pipe, buf, &sd); |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 722 | if (err <= 0) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 723 | if (!ret && err != -ENODATA) |
| 724 | ret = err; |
| 725 | |
| 726 | break; |
| 727 | } |
| 728 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 729 | ret += err; |
| 730 | buf->offset += err; |
| 731 | buf->len -= err; |
| 732 | |
| 733 | sd.len -= err; |
| 734 | sd.pos += err; |
| 735 | sd.total_len -= err; |
| 736 | if (sd.len) |
| 737 | continue; |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 738 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 739 | if (!buf->len) { |
| 740 | buf->ops = NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 741 | ops->release(pipe, buf); |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 742 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 743 | pipe->nrbufs--; |
| 744 | if (pipe->inode) |
| 745 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 746 | } |
| 747 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 748 | if (!sd.total_len) |
| 749 | break; |
| 750 | } |
| 751 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 752 | if (pipe->nrbufs) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 753 | continue; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 754 | if (!pipe->writers) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 755 | break; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 756 | if (!pipe->waiting_writers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 757 | if (ret) |
| 758 | break; |
| 759 | } |
| 760 | |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 761 | if (flags & SPLICE_F_NONBLOCK) { |
| 762 | if (!ret) |
| 763 | ret = -EAGAIN; |
| 764 | break; |
| 765 | } |
| 766 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 767 | if (signal_pending(current)) { |
| 768 | if (!ret) |
| 769 | ret = -ERESTARTSYS; |
| 770 | break; |
| 771 | } |
| 772 | |
| 773 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 774 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 775 | if (waitqueue_active(&pipe->wait)) |
| 776 | wake_up_interruptible_sync(&pipe->wait); |
| 777 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 778 | do_wakeup = 0; |
| 779 | } |
| 780 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 781 | pipe_wait(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 782 | } |
| 783 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 784 | if (pipe->inode) |
| 785 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 786 | |
| 787 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 788 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 789 | if (waitqueue_active(&pipe->wait)) |
| 790 | wake_up_interruptible(&pipe->wait); |
| 791 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 792 | } |
| 793 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 794 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 795 | } |
| 796 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 797 | /** |
| 798 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 799 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 800 | * @out: file to write to |
| 801 | * @len: number of bytes to splice |
| 802 | * @flags: splice modifier flags |
| 803 | * |
| 804 | * Will either move or copy pages (determined by @flags options) from |
| 805 | * the given pipe inode to the given file. |
| 806 | * |
| 807 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 808 | ssize_t |
| 809 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 810 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 811 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 812 | struct address_space *mapping = out->f_mapping; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 813 | ssize_t ret; |
| 814 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 815 | ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 816 | if (ret > 0) { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 817 | struct inode *inode = mapping->host; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 818 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 819 | *ppos += ret; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 820 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 821 | /* |
| 822 | * If file or inode is SYNC and we actually wrote some data, |
| 823 | * sync it. |
| 824 | */ |
| 825 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 826 | int err; |
| 827 | |
| 828 | mutex_lock(&inode->i_mutex); |
| 829 | err = generic_osync_inode(inode, mapping, |
| 830 | OSYNC_METADATA|OSYNC_DATA); |
| 831 | mutex_unlock(&inode->i_mutex); |
| 832 | |
| 833 | if (err) |
| 834 | ret = err; |
| 835 | } |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 836 | } |
| 837 | |
| 838 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 839 | } |
| 840 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 841 | EXPORT_SYMBOL(generic_file_splice_write); |
| 842 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 843 | /** |
| 844 | * generic_splice_sendpage - splice data from a pipe to a socket |
| 845 | * @inode: pipe inode |
| 846 | * @out: socket to write to |
| 847 | * @len: number of bytes to splice |
| 848 | * @flags: splice modifier flags |
| 849 | * |
| 850 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 851 | * is involved. |
| 852 | * |
| 853 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 854 | 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] | 855 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 856 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 857 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 858 | } |
| 859 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 860 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 861 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 862 | /* |
| 863 | * Attempt to initiate a splice from pipe to file. |
| 864 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 865 | 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] | 866 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 867 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 868 | int ret; |
| 869 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 870 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 871 | return -EINVAL; |
| 872 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 873 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 874 | return -EBADF; |
| 875 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 876 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 877 | if (unlikely(ret < 0)) |
| 878 | return ret; |
| 879 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 880 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 881 | } |
| 882 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 883 | /* |
| 884 | * Attempt to initiate a splice from a file to a pipe. |
| 885 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 886 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 887 | struct pipe_inode_info *pipe, size_t len, |
| 888 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 889 | { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 890 | loff_t isize, left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 891 | int ret; |
| 892 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 893 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 894 | return -EINVAL; |
| 895 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 896 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 897 | return -EBADF; |
| 898 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 899 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 900 | if (unlikely(ret < 0)) |
| 901 | return ret; |
| 902 | |
| 903 | isize = i_size_read(in->f_mapping->host); |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 904 | if (unlikely(*ppos >= isize)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 905 | return 0; |
| 906 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 907 | left = isize - *ppos; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 908 | if (unlikely(left < len)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 909 | len = left; |
| 910 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 911 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 912 | } |
| 913 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 914 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 915 | size_t len, unsigned int flags) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 916 | { |
| 917 | struct pipe_inode_info *pipe; |
| 918 | long ret, bytes; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 919 | loff_t out_off; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 920 | umode_t i_mode; |
| 921 | int i; |
| 922 | |
| 923 | /* |
| 924 | * We require the input being a regular file, as we don't want to |
| 925 | * randomly drop data for eg socket -> socket splicing. Use the |
| 926 | * piped splicing for that! |
| 927 | */ |
| 928 | i_mode = in->f_dentry->d_inode->i_mode; |
| 929 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 930 | return -EINVAL; |
| 931 | |
| 932 | /* |
| 933 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 934 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 935 | */ |
| 936 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 937 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 938 | pipe = alloc_pipe_info(NULL); |
| 939 | if (!pipe) |
| 940 | return -ENOMEM; |
| 941 | |
| 942 | /* |
| 943 | * 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] | 944 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 945 | * PIPE_READERS appropriately. |
| 946 | */ |
| 947 | pipe->readers = 1; |
| 948 | |
| 949 | current->splice_pipe = pipe; |
| 950 | } |
| 951 | |
| 952 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 953 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 954 | */ |
| 955 | ret = 0; |
| 956 | bytes = 0; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 957 | out_off = 0; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 958 | |
| 959 | while (len) { |
| 960 | size_t read_len, max_read_len; |
| 961 | |
| 962 | /* |
| 963 | * Do at most PIPE_BUFFERS pages worth of transfer: |
| 964 | */ |
| 965 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); |
| 966 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 967 | ret = do_splice_to(in, ppos, pipe, max_read_len, flags); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 968 | if (unlikely(ret < 0)) |
| 969 | goto out_release; |
| 970 | |
| 971 | read_len = ret; |
| 972 | |
| 973 | /* |
| 974 | * NOTE: nonblocking mode only applies to the input. We |
| 975 | * must not do the output in nonblocking mode as then we |
| 976 | * could get stuck data in the internal pipe: |
| 977 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 978 | ret = do_splice_from(pipe, out, &out_off, read_len, |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 979 | flags & ~SPLICE_F_NONBLOCK); |
| 980 | if (unlikely(ret < 0)) |
| 981 | goto out_release; |
| 982 | |
| 983 | bytes += ret; |
| 984 | len -= ret; |
| 985 | |
| 986 | /* |
| 987 | * In nonblocking mode, if we got back a short read then |
| 988 | * that was due to either an IO error or due to the |
| 989 | * pagecache entry not being there. In the IO error case |
| 990 | * the _next_ splice attempt will produce a clean IO error |
| 991 | * return value (not a short read), so in both cases it's |
| 992 | * correct to break out of the loop here: |
| 993 | */ |
| 994 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) |
| 995 | break; |
| 996 | } |
| 997 | |
| 998 | pipe->nrbufs = pipe->curbuf = 0; |
| 999 | |
| 1000 | return bytes; |
| 1001 | |
| 1002 | out_release: |
| 1003 | /* |
| 1004 | * If we did an incomplete transfer we must release |
| 1005 | * the pipe buffers in question: |
| 1006 | */ |
| 1007 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1008 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1009 | |
| 1010 | if (buf->ops) { |
| 1011 | buf->ops->release(pipe, buf); |
| 1012 | buf->ops = NULL; |
| 1013 | } |
| 1014 | } |
| 1015 | pipe->nrbufs = pipe->curbuf = 0; |
| 1016 | |
| 1017 | /* |
| 1018 | * If we transferred some data, return the number of bytes: |
| 1019 | */ |
| 1020 | if (bytes > 0) |
| 1021 | return bytes; |
| 1022 | |
| 1023 | return ret; |
| 1024 | } |
| 1025 | |
| 1026 | EXPORT_SYMBOL(do_splice_direct); |
| 1027 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1028 | /* |
| 1029 | * Determine where to splice to/from. |
| 1030 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1031 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1032 | struct file *out, loff_t __user *off_out, |
| 1033 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1034 | { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1035 | struct pipe_inode_info *pipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1036 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1037 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1038 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1039 | pipe = in->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1040 | if (pipe) { |
| 1041 | if (off_in) |
| 1042 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1043 | if (off_out) { |
| 1044 | if (out->f_op->llseek == no_llseek) |
| 1045 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1046 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1047 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1048 | off = &offset; |
| 1049 | } else |
| 1050 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1051 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1052 | ret = do_splice_from(pipe, out, off, len, flags); |
| 1053 | |
| 1054 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1055 | ret = -EFAULT; |
| 1056 | |
| 1057 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1058 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1059 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1060 | pipe = out->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1061 | if (pipe) { |
| 1062 | if (off_out) |
| 1063 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1064 | if (off_in) { |
| 1065 | if (in->f_op->llseek == no_llseek) |
| 1066 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1067 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1068 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1069 | off = &offset; |
| 1070 | } else |
| 1071 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1072 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1073 | ret = do_splice_to(in, off, pipe, len, flags); |
| 1074 | |
| 1075 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1076 | ret = -EFAULT; |
| 1077 | |
| 1078 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1079 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1080 | |
| 1081 | return -EINVAL; |
| 1082 | } |
| 1083 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1084 | /* |
| 1085 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1086 | * partial_page structure, we can map several non-contiguous ranges into |
| 1087 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1088 | * Could easily be exported as a generic helper for other users, in which |
| 1089 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1090 | */ |
| 1091 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1092 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1093 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1094 | { |
| 1095 | int buffers = 0, error = 0; |
| 1096 | |
| 1097 | /* |
| 1098 | * It's ok to take the mmap_sem for reading, even |
| 1099 | * across a "get_user()". |
| 1100 | */ |
| 1101 | down_read(¤t->mm->mmap_sem); |
| 1102 | |
| 1103 | while (nr_vecs) { |
| 1104 | unsigned long off, npages; |
| 1105 | void __user *base; |
| 1106 | size_t len; |
| 1107 | int i; |
| 1108 | |
| 1109 | /* |
| 1110 | * Get user address base and length for this iovec. |
| 1111 | */ |
| 1112 | error = get_user(base, &iov->iov_base); |
| 1113 | if (unlikely(error)) |
| 1114 | break; |
| 1115 | error = get_user(len, &iov->iov_len); |
| 1116 | if (unlikely(error)) |
| 1117 | break; |
| 1118 | |
| 1119 | /* |
| 1120 | * Sanity check this iovec. 0 read succeeds. |
| 1121 | */ |
| 1122 | if (unlikely(!len)) |
| 1123 | break; |
| 1124 | error = -EFAULT; |
| 1125 | if (unlikely(!base)) |
| 1126 | break; |
| 1127 | |
| 1128 | /* |
| 1129 | * Get this base offset and number of pages, then map |
| 1130 | * in the user pages. |
| 1131 | */ |
| 1132 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1133 | |
| 1134 | /* |
| 1135 | * If asked for alignment, the offset must be zero and the |
| 1136 | * length a multiple of the PAGE_SIZE. |
| 1137 | */ |
| 1138 | error = -EINVAL; |
| 1139 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1140 | break; |
| 1141 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1142 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1143 | if (npages > PIPE_BUFFERS - buffers) |
| 1144 | npages = PIPE_BUFFERS - buffers; |
| 1145 | |
| 1146 | error = get_user_pages(current, current->mm, |
| 1147 | (unsigned long) base, npages, 0, 0, |
| 1148 | &pages[buffers], NULL); |
| 1149 | |
| 1150 | if (unlikely(error <= 0)) |
| 1151 | break; |
| 1152 | |
| 1153 | /* |
| 1154 | * Fill this contiguous range into the partial page map. |
| 1155 | */ |
| 1156 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1157 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1158 | |
| 1159 | partial[buffers].offset = off; |
| 1160 | partial[buffers].len = plen; |
| 1161 | |
| 1162 | off = 0; |
| 1163 | len -= plen; |
| 1164 | buffers++; |
| 1165 | } |
| 1166 | |
| 1167 | /* |
| 1168 | * We didn't complete this iov, stop here since it probably |
| 1169 | * means we have to move some of this into a pipe to |
| 1170 | * be able to continue. |
| 1171 | */ |
| 1172 | if (len) |
| 1173 | break; |
| 1174 | |
| 1175 | /* |
| 1176 | * Don't continue if we mapped fewer pages than we asked for, |
| 1177 | * or if we mapped the max number of pages that we have |
| 1178 | * room for. |
| 1179 | */ |
| 1180 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1181 | break; |
| 1182 | |
| 1183 | nr_vecs--; |
| 1184 | iov++; |
| 1185 | } |
| 1186 | |
| 1187 | up_read(¤t->mm->mmap_sem); |
| 1188 | |
| 1189 | if (buffers) |
| 1190 | return buffers; |
| 1191 | |
| 1192 | return error; |
| 1193 | } |
| 1194 | |
| 1195 | /* |
| 1196 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1197 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1198 | * to file). In both cases the output is a pipe, naturally. |
| 1199 | * |
| 1200 | * Note that vmsplice only supports splicing _from_ user memory to a pipe, |
| 1201 | * not the other way around. Splicing from user memory is a simple operation |
| 1202 | * that can be supported without any funky alignment restrictions or nasty |
| 1203 | * vm tricks. We simply map in the user memory and fill them into a pipe. |
| 1204 | * The reverse isn't quite as easy, though. There are two possible solutions |
| 1205 | * for that: |
| 1206 | * |
| 1207 | * - memcpy() the data internally, at which point we might as well just |
| 1208 | * do a regular read() on the buffer anyway. |
| 1209 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1210 | * has restriction limitations on both ends of the pipe). |
| 1211 | * |
| 1212 | * Alas, it isn't here. |
| 1213 | * |
| 1214 | */ |
| 1215 | static long do_vmsplice(struct file *file, const struct iovec __user *iov, |
| 1216 | unsigned long nr_segs, unsigned int flags) |
| 1217 | { |
| 1218 | struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; |
| 1219 | struct page *pages[PIPE_BUFFERS]; |
| 1220 | struct partial_page partial[PIPE_BUFFERS]; |
| 1221 | struct splice_pipe_desc spd = { |
| 1222 | .pages = pages, |
| 1223 | .partial = partial, |
| 1224 | .flags = flags, |
| 1225 | .ops = &user_page_pipe_buf_ops, |
| 1226 | }; |
| 1227 | |
| 1228 | if (unlikely(!pipe)) |
| 1229 | return -EBADF; |
| 1230 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1231 | return -EINVAL; |
| 1232 | else if (unlikely(!nr_segs)) |
| 1233 | return 0; |
| 1234 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1235 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1236 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1237 | if (spd.nr_pages <= 0) |
| 1238 | return spd.nr_pages; |
| 1239 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1240 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1241 | } |
| 1242 | |
| 1243 | asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, |
| 1244 | unsigned long nr_segs, unsigned int flags) |
| 1245 | { |
| 1246 | struct file *file; |
| 1247 | long error; |
| 1248 | int fput; |
| 1249 | |
| 1250 | error = -EBADF; |
| 1251 | file = fget_light(fd, &fput); |
| 1252 | if (file) { |
| 1253 | if (file->f_mode & FMODE_WRITE) |
| 1254 | error = do_vmsplice(file, iov, nr_segs, flags); |
| 1255 | |
| 1256 | fput_light(file, fput); |
| 1257 | } |
| 1258 | |
| 1259 | return error; |
| 1260 | } |
| 1261 | |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1262 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
| 1263 | int fd_out, loff_t __user *off_out, |
| 1264 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1265 | { |
| 1266 | long error; |
| 1267 | struct file *in, *out; |
| 1268 | int fput_in, fput_out; |
| 1269 | |
| 1270 | if (unlikely(!len)) |
| 1271 | return 0; |
| 1272 | |
| 1273 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1274 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1275 | if (in) { |
| 1276 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1277 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1278 | if (out) { |
| 1279 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1280 | error = do_splice(in, off_in, |
| 1281 | out, off_out, |
| 1282 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1283 | fput_light(out, fput_out); |
| 1284 | } |
| 1285 | } |
| 1286 | |
| 1287 | fput_light(in, fput_in); |
| 1288 | } |
| 1289 | |
| 1290 | return error; |
| 1291 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1292 | |
| 1293 | /* |
| 1294 | * Link contents of ipipe to opipe. |
| 1295 | */ |
| 1296 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1297 | struct pipe_inode_info *opipe, |
| 1298 | size_t len, unsigned int flags) |
| 1299 | { |
| 1300 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1301 | int ret, do_wakeup, i, ipipe_first; |
| 1302 | |
| 1303 | ret = do_wakeup = ipipe_first = 0; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1304 | |
| 1305 | /* |
| 1306 | * Potential ABBA deadlock, work around it by ordering lock |
| 1307 | * grabbing by inode address. Otherwise two different processes |
| 1308 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1309 | */ |
| 1310 | if (ipipe->inode < opipe->inode) { |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1311 | ipipe_first = 1; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1312 | mutex_lock(&ipipe->inode->i_mutex); |
| 1313 | mutex_lock(&opipe->inode->i_mutex); |
| 1314 | } else { |
| 1315 | mutex_lock(&opipe->inode->i_mutex); |
| 1316 | mutex_lock(&ipipe->inode->i_mutex); |
| 1317 | } |
| 1318 | |
| 1319 | for (i = 0;; i++) { |
| 1320 | if (!opipe->readers) { |
| 1321 | send_sig(SIGPIPE, current, 0); |
| 1322 | if (!ret) |
| 1323 | ret = -EPIPE; |
| 1324 | break; |
| 1325 | } |
| 1326 | if (ipipe->nrbufs - i) { |
| 1327 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1328 | |
| 1329 | /* |
| 1330 | * If we have room, fill this buffer |
| 1331 | */ |
| 1332 | if (opipe->nrbufs < PIPE_BUFFERS) { |
| 1333 | int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1334 | |
| 1335 | /* |
| 1336 | * Get a reference to this pipe buffer, |
| 1337 | * so we can copy the contents over. |
| 1338 | */ |
| 1339 | ibuf->ops->get(ipipe, ibuf); |
| 1340 | |
| 1341 | obuf = opipe->bufs + nbuf; |
| 1342 | *obuf = *ibuf; |
| 1343 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1344 | /* |
| 1345 | * Don't inherit the gift flag, we need to |
| 1346 | * prevent multiple steals of this page. |
| 1347 | */ |
| 1348 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1349 | |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1350 | if (obuf->len > len) |
| 1351 | obuf->len = len; |
| 1352 | |
| 1353 | opipe->nrbufs++; |
| 1354 | do_wakeup = 1; |
| 1355 | ret += obuf->len; |
| 1356 | len -= obuf->len; |
| 1357 | |
| 1358 | if (!len) |
| 1359 | break; |
| 1360 | if (opipe->nrbufs < PIPE_BUFFERS) |
| 1361 | continue; |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * We have input available, but no output room. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1366 | * If we already copied data, return that. If we |
| 1367 | * need to drop the opipe lock, it must be ordered |
| 1368 | * last to avoid deadlocks. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1369 | */ |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1370 | if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1371 | if (!ret) |
| 1372 | ret = -EAGAIN; |
| 1373 | break; |
| 1374 | } |
| 1375 | if (signal_pending(current)) { |
| 1376 | if (!ret) |
| 1377 | ret = -ERESTARTSYS; |
| 1378 | break; |
| 1379 | } |
| 1380 | if (do_wakeup) { |
| 1381 | smp_mb(); |
| 1382 | if (waitqueue_active(&opipe->wait)) |
| 1383 | wake_up_interruptible(&opipe->wait); |
| 1384 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1385 | do_wakeup = 0; |
| 1386 | } |
| 1387 | |
| 1388 | opipe->waiting_writers++; |
| 1389 | pipe_wait(opipe); |
| 1390 | opipe->waiting_writers--; |
| 1391 | continue; |
| 1392 | } |
| 1393 | |
| 1394 | /* |
| 1395 | * No input buffers, do the usual checks for available |
| 1396 | * writers and blocking and wait if necessary |
| 1397 | */ |
| 1398 | if (!ipipe->writers) |
| 1399 | break; |
| 1400 | if (!ipipe->waiting_writers) { |
| 1401 | if (ret) |
| 1402 | break; |
| 1403 | } |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1404 | /* |
| 1405 | * pipe_wait() drops the ipipe mutex. To avoid deadlocks |
| 1406 | * with another process, we can only safely do that if |
| 1407 | * the ipipe lock is ordered last. |
| 1408 | */ |
| 1409 | if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1410 | if (!ret) |
| 1411 | ret = -EAGAIN; |
| 1412 | break; |
| 1413 | } |
| 1414 | if (signal_pending(current)) { |
| 1415 | if (!ret) |
| 1416 | ret = -ERESTARTSYS; |
| 1417 | break; |
| 1418 | } |
| 1419 | |
| 1420 | if (waitqueue_active(&ipipe->wait)) |
| 1421 | wake_up_interruptible_sync(&ipipe->wait); |
| 1422 | kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT); |
| 1423 | |
| 1424 | pipe_wait(ipipe); |
| 1425 | } |
| 1426 | |
| 1427 | mutex_unlock(&ipipe->inode->i_mutex); |
| 1428 | mutex_unlock(&opipe->inode->i_mutex); |
| 1429 | |
| 1430 | if (do_wakeup) { |
| 1431 | smp_mb(); |
| 1432 | if (waitqueue_active(&opipe->wait)) |
| 1433 | wake_up_interruptible(&opipe->wait); |
| 1434 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1435 | } |
| 1436 | |
| 1437 | return ret; |
| 1438 | } |
| 1439 | |
| 1440 | /* |
| 1441 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1442 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1443 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1444 | * applicable one is SPLICE_F_NONBLOCK. |
| 1445 | */ |
| 1446 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1447 | unsigned int flags) |
| 1448 | { |
| 1449 | struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; |
| 1450 | struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; |
| 1451 | |
| 1452 | /* |
| 1453 | * Link ipipe to the two output pipes, consuming as we go along. |
| 1454 | */ |
| 1455 | if (ipipe && opipe) |
| 1456 | return link_pipe(ipipe, opipe, len, flags); |
| 1457 | |
| 1458 | return -EINVAL; |
| 1459 | } |
| 1460 | |
| 1461 | asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) |
| 1462 | { |
| 1463 | struct file *in; |
| 1464 | int error, fput_in; |
| 1465 | |
| 1466 | if (unlikely(!len)) |
| 1467 | return 0; |
| 1468 | |
| 1469 | error = -EBADF; |
| 1470 | in = fget_light(fdin, &fput_in); |
| 1471 | if (in) { |
| 1472 | if (in->f_mode & FMODE_READ) { |
| 1473 | int fput_out; |
| 1474 | struct file *out = fget_light(fdout, &fput_out); |
| 1475 | |
| 1476 | if (out) { |
| 1477 | if (out->f_mode & FMODE_WRITE) |
| 1478 | error = do_tee(in, out, len, flags); |
| 1479 | fput_light(out, fput_out); |
| 1480 | } |
| 1481 | } |
| 1482 | fput_light(in, fput_in); |
| 1483 | } |
| 1484 | |
| 1485 | return error; |
| 1486 | } |