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> |
| 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 | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 54 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 55 | struct pipe_buffer *buf) |
| 56 | { |
| 57 | struct page *page = buf->page; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 58 | struct address_space *mapping; |
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 | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 62 | mapping = page_mapping(page); |
| 63 | if (mapping) { |
| 64 | WARN_ON(!PageUptodate(page)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 65 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 66 | /* |
| 67 | * At least for ext2 with nobh option, we need to wait on |
| 68 | * writeback completing on this page, since we'll remove it |
| 69 | * from the pagecache. Otherwise truncate wont wait on the |
| 70 | * page, allowing the disk blocks to be reused by someone else |
| 71 | * before we actually wrote our data to them. fs corruption |
| 72 | * ensues. |
| 73 | */ |
| 74 | wait_on_page_writeback(page); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 75 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 76 | if (PagePrivate(page)) |
| 77 | try_to_release_page(page, mapping_gfp_mask(mapping)); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 78 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 79 | /* |
| 80 | * If we succeeded in removing the mapping, set LRU flag |
| 81 | * and return good. |
| 82 | */ |
| 83 | if (remove_mapping(mapping, page)) { |
| 84 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 85 | return 0; |
| 86 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 87 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 88 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 89 | /* |
| 90 | * Raced with truncate or failed to remove page from current |
| 91 | * address space, unlock and return failure. |
| 92 | */ |
| 93 | unlock_page(page); |
| 94 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 95 | } |
| 96 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 97 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 98 | struct pipe_buffer *buf) |
| 99 | { |
| 100 | page_cache_release(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 101 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 102 | } |
| 103 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 104 | static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 105 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 106 | { |
| 107 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 108 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 109 | |
| 110 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 111 | lock_page(page); |
| 112 | |
| 113 | /* |
| 114 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 115 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 116 | */ |
| 117 | if (!page->mapping) { |
| 118 | err = -ENODATA; |
| 119 | goto error; |
| 120 | } |
| 121 | |
| 122 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 123 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 124 | */ |
| 125 | if (!PageUptodate(page)) { |
| 126 | err = -EIO; |
| 127 | goto error; |
| 128 | } |
| 129 | |
| 130 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 131 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 132 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 133 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 134 | } |
| 135 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 136 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 137 | error: |
| 138 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 139 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 140 | } |
| 141 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 142 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { |
| 143 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 144 | .map = generic_pipe_buf_map, |
| 145 | .unmap = generic_pipe_buf_unmap, |
| 146 | .pin = page_cache_pipe_buf_pin, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 147 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 148 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 149 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 150 | }; |
| 151 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 152 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 153 | struct pipe_buffer *buf) |
| 154 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 155 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 156 | return 1; |
| 157 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 158 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 159 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 160 | } |
| 161 | |
| 162 | static struct pipe_buf_operations user_page_pipe_buf_ops = { |
| 163 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 164 | .map = generic_pipe_buf_map, |
| 165 | .unmap = generic_pipe_buf_unmap, |
| 166 | .pin = generic_pipe_buf_pin, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 167 | .release = page_cache_pipe_buf_release, |
| 168 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 169 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 170 | }; |
| 171 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 172 | /* |
| 173 | * Pipe output worker. This sets up our pipe format with the page cache |
| 174 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). |
| 175 | */ |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 176 | static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 177 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 178 | { |
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 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 185 | if (pipe->inode) |
| 186 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 187 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 188 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 189 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 190 | send_sig(SIGPIPE, current, 0); |
| 191 | if (!ret) |
| 192 | ret = -EPIPE; |
| 193 | break; |
| 194 | } |
| 195 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 196 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 197 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 198 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 199 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 200 | buf->page = spd->pages[page_nr]; |
| 201 | buf->offset = spd->partial[page_nr].offset; |
| 202 | buf->len = spd->partial[page_nr].len; |
| 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 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 247 | if (pipe->inode) |
| 248 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 249 | |
| 250 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 251 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 252 | if (waitqueue_active(&pipe->wait)) |
| 253 | wake_up_interruptible(&pipe->wait); |
| 254 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 255 | } |
| 256 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 257 | while (page_nr < spd->nr_pages) |
| 258 | page_cache_release(spd->pages[page_nr++]); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 259 | |
| 260 | return ret; |
| 261 | } |
| 262 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 263 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 264 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 265 | struct pipe_inode_info *pipe, size_t len, |
| 266 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 267 | { |
| 268 | struct address_space *mapping = in->f_mapping; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 269 | unsigned int loff, nr_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 270 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 271 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 272 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 273 | pgoff_t index, end_index; |
| 274 | loff_t isize; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 275 | size_t total_len; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 276 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 277 | struct splice_pipe_desc spd = { |
| 278 | .pages = pages, |
| 279 | .partial = partial, |
| 280 | .flags = flags, |
| 281 | .ops = &page_cache_pipe_buf_ops, |
| 282 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 283 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 284 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 285 | loff = *ppos & ~PAGE_CACHE_MASK; |
| 286 | nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 287 | |
| 288 | if (nr_pages > PIPE_BUFFERS) |
| 289 | nr_pages = PIPE_BUFFERS; |
| 290 | |
| 291 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 292 | * Initiate read-ahead on this page range. however, don't call into |
Jens Axboe | 0b749ce | 2006-04-10 09:05:04 +0200 | [diff] [blame] | 293 | * read-ahead if this is a non-zero offset (we are likely doing small |
| 294 | * chunk splice and the page is already there) for a single page. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 295 | */ |
Jens Axboe | eb645a2 | 2006-04-27 08:44:27 +0200 | [diff] [blame] | 296 | if (!loff || nr_pages > 1) |
| 297 | page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 298 | |
| 299 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 300 | * Now fill in the holes: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 301 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 302 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 303 | total_len = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 304 | |
| 305 | /* |
| 306 | * Lookup the (hopefully) full range of pages we need. |
| 307 | */ |
| 308 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
| 309 | |
| 310 | /* |
| 311 | * If find_get_pages_contig() returned fewer pages than we needed, |
| 312 | * allocate the rest. |
| 313 | */ |
| 314 | index += spd.nr_pages; |
| 315 | while (spd.nr_pages < nr_pages) { |
| 316 | /* |
| 317 | * Page could be there, find_get_pages_contig() breaks on |
| 318 | * the first hole. |
| 319 | */ |
| 320 | page = find_get_page(mapping, index); |
| 321 | if (!page) { |
| 322 | /* |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 323 | * Make sure the read-ahead engine is notified |
| 324 | * about this failure. |
| 325 | */ |
| 326 | handle_ra_miss(mapping, &in->f_ra, index); |
| 327 | |
| 328 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 329 | * page didn't exist, allocate one. |
| 330 | */ |
| 331 | page = page_cache_alloc_cold(mapping); |
| 332 | if (!page) |
| 333 | break; |
| 334 | |
| 335 | error = add_to_page_cache_lru(page, mapping, index, |
| 336 | mapping_gfp_mask(mapping)); |
| 337 | if (unlikely(error)) { |
| 338 | page_cache_release(page); |
Jens Axboe | a054887 | 2006-05-03 10:58:22 +0200 | [diff] [blame] | 339 | if (error == -EEXIST) |
| 340 | continue; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 341 | break; |
| 342 | } |
| 343 | /* |
| 344 | * add_to_page_cache() locks the page, unlock it |
| 345 | * to avoid convoluting the logic below even more. |
| 346 | */ |
| 347 | unlock_page(page); |
| 348 | } |
| 349 | |
| 350 | pages[spd.nr_pages++] = page; |
| 351 | index++; |
| 352 | } |
| 353 | |
| 354 | /* |
| 355 | * Now loop over the map and see if we need to start IO on any |
| 356 | * pages, fill in the partial map, etc. |
| 357 | */ |
| 358 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 359 | nr_pages = spd.nr_pages; |
| 360 | spd.nr_pages = 0; |
| 361 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 362 | unsigned int this_len; |
| 363 | |
| 364 | if (!len) |
| 365 | break; |
| 366 | |
| 367 | /* |
| 368 | * this_len is the max we'll use from this page |
| 369 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 370 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 371 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 372 | |
| 373 | /* |
| 374 | * If the page isn't uptodate, we may need to start io on it |
| 375 | */ |
| 376 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 377 | /* |
| 378 | * If in nonblock mode then dont block on waiting |
| 379 | * for an in-flight io page |
| 380 | */ |
| 381 | if (flags & SPLICE_F_NONBLOCK) |
| 382 | break; |
| 383 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 384 | lock_page(page); |
| 385 | |
| 386 | /* |
| 387 | * page was truncated, stop here. if this isn't the |
| 388 | * first page, we'll just complete what we already |
| 389 | * added |
| 390 | */ |
| 391 | if (!page->mapping) { |
| 392 | unlock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 393 | break; |
| 394 | } |
| 395 | /* |
| 396 | * page was already under io and is now done, great |
| 397 | */ |
| 398 | if (PageUptodate(page)) { |
| 399 | unlock_page(page); |
| 400 | goto fill_it; |
| 401 | } |
| 402 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 403 | /* |
| 404 | * need to read in the page |
| 405 | */ |
| 406 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 407 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 408 | /* |
| 409 | * We really should re-lookup the page here, |
| 410 | * but it complicates things a lot. Instead |
| 411 | * lets just do what we already stored, and |
| 412 | * we'll get it the next time we are called. |
| 413 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 414 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 415 | error = 0; |
| 416 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 417 | break; |
| 418 | } |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 419 | |
| 420 | /* |
| 421 | * i_size must be checked after ->readpage(). |
| 422 | */ |
| 423 | isize = i_size_read(mapping->host); |
| 424 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 425 | if (unlikely(!isize || index > end_index)) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 426 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 427 | |
| 428 | /* |
| 429 | * if this is the last page, see if we need to shrink |
| 430 | * the length and stop |
| 431 | */ |
| 432 | if (end_index == index) { |
| 433 | loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 434 | if (total_len + loff > isize) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 435 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 436 | /* |
| 437 | * force quit after adding this page |
| 438 | */ |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 439 | len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 440 | this_len = min(this_len, loff); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 441 | loff = 0; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 442 | } |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 443 | } |
| 444 | fill_it: |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 445 | partial[page_nr].offset = loff; |
| 446 | partial[page_nr].len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 447 | len -= this_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 448 | total_len += this_len; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 449 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 450 | spd.nr_pages++; |
| 451 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 452 | } |
| 453 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 454 | /* |
| 455 | * Release any pages at the end, if we quit early. 'i' is how far |
| 456 | * we got, 'nr_pages' is how many pages are in the map. |
| 457 | */ |
| 458 | while (page_nr < nr_pages) |
| 459 | page_cache_release(pages[page_nr++]); |
| 460 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 461 | if (spd.nr_pages) |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 462 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 463 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 464 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 465 | } |
| 466 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 467 | /** |
| 468 | * generic_file_splice_read - splice data from file to a pipe |
| 469 | * @in: file to splice from |
| 470 | * @pipe: pipe to splice to |
| 471 | * @len: number of bytes to splice |
| 472 | * @flags: splice modifier flags |
| 473 | * |
| 474 | * Will read pages from given file and fill them into a pipe. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 475 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 476 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 477 | struct pipe_inode_info *pipe, size_t len, |
| 478 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 479 | { |
| 480 | ssize_t spliced; |
| 481 | int ret; |
| 482 | |
| 483 | ret = 0; |
| 484 | spliced = 0; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 485 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 486 | while (len) { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 487 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 488 | |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 489 | if (ret < 0) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 490 | break; |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 491 | else if (!ret) { |
| 492 | if (spliced) |
| 493 | break; |
| 494 | if (flags & SPLICE_F_NONBLOCK) { |
| 495 | ret = -EAGAIN; |
| 496 | break; |
| 497 | } |
| 498 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 499 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 500 | *ppos += ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 501 | len -= ret; |
| 502 | spliced += ret; |
| 503 | } |
| 504 | |
| 505 | if (spliced) |
| 506 | return spliced; |
| 507 | |
| 508 | return ret; |
| 509 | } |
| 510 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 511 | EXPORT_SYMBOL(generic_file_splice_read); |
| 512 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 513 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 514 | * 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] | 515 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 516 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 517 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 518 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 519 | { |
| 520 | struct file *file = sd->file; |
| 521 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 522 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 523 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 524 | ret = buf->ops->pin(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 525 | if (!ret) { |
| 526 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 527 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 528 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 529 | sd->len, &pos, more); |
| 530 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 531 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 532 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 533 | } |
| 534 | |
| 535 | /* |
| 536 | * This is a little more tricky than the file -> pipe splicing. There are |
| 537 | * basically three cases: |
| 538 | * |
| 539 | * - Destination page already exists in the address space and there |
| 540 | * are users of it. For that case we have no other option that |
| 541 | * copying the data. Tough luck. |
| 542 | * - Destination page already exists in the address space, but there |
| 543 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 544 | * through to last case. |
| 545 | * - Destination page does not exist, we can add the pipe page to |
| 546 | * the page cache and avoid the copy. |
| 547 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 548 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 549 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 550 | * file address space page cache. This is possible if no one else has |
| 551 | * the pipe page referenced outside of the pipe and page cache. If |
| 552 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 553 | * 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] | 554 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 555 | static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 556 | struct splice_desc *sd) |
| 557 | { |
| 558 | struct file *file = sd->file; |
| 559 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 560 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 561 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 562 | struct page *page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 563 | pgoff_t index; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 564 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 565 | |
| 566 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 567 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 568 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 569 | ret = buf->ops->pin(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 570 | if (unlikely(ret)) |
| 571 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 572 | |
| 573 | index = sd->pos >> PAGE_CACHE_SHIFT; |
| 574 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 575 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 576 | this_len = sd->len; |
| 577 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 578 | this_len = PAGE_CACHE_SIZE - offset; |
| 579 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 580 | /* |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 581 | * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full |
| 582 | * page. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 583 | */ |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 584 | if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) { |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 585 | /* |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 586 | * If steal succeeds, buf->page is now pruned from the |
| 587 | * pagecache and we can reuse it. The page will also be |
| 588 | * locked on successful return. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 589 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 590 | if (buf->ops->steal(pipe, buf)) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 591 | goto find_page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 592 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 593 | page = buf->page; |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 594 | if (add_to_page_cache(page, mapping, index, gfp_mask)) { |
| 595 | unlock_page(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 596 | goto find_page; |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 597 | } |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 598 | |
| 599 | page_cache_get(page); |
| 600 | |
| 601 | if (!(buf->flags & PIPE_BUF_FLAG_LRU)) |
| 602 | lru_cache_add(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 603 | } else { |
| 604 | find_page: |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 605 | page = find_lock_page(mapping, index); |
| 606 | if (!page) { |
| 607 | ret = -ENOMEM; |
| 608 | page = page_cache_alloc_cold(mapping); |
| 609 | if (unlikely(!page)) |
Jens Axboe | e6e80f2 | 2006-10-11 10:03:09 +0200 | [diff] [blame] | 610 | goto out_ret; |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 611 | |
| 612 | /* |
| 613 | * This will also lock the page |
| 614 | */ |
| 615 | ret = add_to_page_cache_lru(page, mapping, index, |
| 616 | gfp_mask); |
| 617 | if (unlikely(ret)) |
| 618 | goto out; |
| 619 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 620 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 621 | /* |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 622 | * We get here with the page locked. If the page is also |
| 623 | * uptodate, we don't need to do more. If it isn't, we |
| 624 | * may need to bring it in if we are not going to overwrite |
| 625 | * the full page. |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 626 | */ |
| 627 | if (!PageUptodate(page)) { |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 628 | if (this_len < PAGE_CACHE_SIZE) { |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 629 | ret = mapping->a_ops->readpage(file, page); |
| 630 | if (unlikely(ret)) |
| 631 | goto out; |
| 632 | |
| 633 | lock_page(page); |
| 634 | |
| 635 | if (!PageUptodate(page)) { |
| 636 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 637 | * Page got invalidated, repeat. |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 638 | */ |
| 639 | if (!page->mapping) { |
| 640 | unlock_page(page); |
| 641 | page_cache_release(page); |
| 642 | goto find_page; |
| 643 | } |
| 644 | ret = -EIO; |
| 645 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 646 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 647 | } else |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 648 | SetPageUptodate(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 649 | } |
| 650 | } |
| 651 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 652 | ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len); |
Jens Axboe | bfc4ee3 | 2006-05-03 10:35:10 +0200 | [diff] [blame] | 653 | if (unlikely(ret)) { |
| 654 | loff_t isize = i_size_read(mapping->host); |
| 655 | |
| 656 | if (ret != AOP_TRUNCATED_PAGE) |
| 657 | unlock_page(page); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 658 | page_cache_release(page); |
Jens Axboe | bfc4ee3 | 2006-05-03 10:35:10 +0200 | [diff] [blame] | 659 | if (ret == AOP_TRUNCATED_PAGE) |
| 660 | goto find_page; |
| 661 | |
| 662 | /* |
| 663 | * prepare_write() may have instantiated a few blocks |
| 664 | * outside i_size. Trim these off again. |
| 665 | */ |
| 666 | if (sd->pos + this_len > isize) |
| 667 | vmtruncate(mapping->host, isize); |
| 668 | |
Jens Axboe | e6e80f2 | 2006-10-11 10:03:09 +0200 | [diff] [blame] | 669 | goto out_ret; |
Jens Axboe | bfc4ee3 | 2006-05-03 10:35:10 +0200 | [diff] [blame] | 670 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 671 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 672 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 673 | /* |
| 674 | * Careful, ->map() uses KM_USER0! |
| 675 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 676 | char *src = buf->ops->map(pipe, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 677 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 678 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 679 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 680 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 681 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 682 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 683 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 684 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 685 | ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 686 | if (!ret) { |
| 687 | /* |
| 688 | * Return the number of bytes written and mark page as |
| 689 | * accessed, we are now done! |
| 690 | */ |
| 691 | ret = this_len; |
| 692 | mark_page_accessed(page); |
| 693 | balance_dirty_pages_ratelimited(mapping); |
| 694 | } else if (ret == AOP_TRUNCATED_PAGE) { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 695 | page_cache_release(page); |
| 696 | goto find_page; |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 697 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 698 | out: |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 699 | page_cache_release(page); |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 700 | unlock_page(page); |
Jens Axboe | e6e80f2 | 2006-10-11 10:03:09 +0200 | [diff] [blame] | 701 | out_ret: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 702 | return ret; |
| 703 | } |
| 704 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 705 | /* |
| 706 | * Pipe input worker. Most of this logic works like a regular pipe, the |
| 707 | * key here is the 'actor' worker passed in that actually moves the data |
| 708 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. |
| 709 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 710 | static ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, |
| 711 | struct file *out, loff_t *ppos, size_t len, |
| 712 | unsigned int flags, splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 713 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 714 | int ret, do_wakeup, err; |
| 715 | struct splice_desc sd; |
| 716 | |
| 717 | ret = 0; |
| 718 | do_wakeup = 0; |
| 719 | |
| 720 | sd.total_len = len; |
| 721 | sd.flags = flags; |
| 722 | sd.file = out; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 723 | sd.pos = *ppos; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 724 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 725 | for (;;) { |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 726 | if (pipe->nrbufs) { |
| 727 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 728 | struct pipe_buf_operations *ops = buf->ops; |
| 729 | |
| 730 | sd.len = buf->len; |
| 731 | if (sd.len > sd.total_len) |
| 732 | sd.len = sd.total_len; |
| 733 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 734 | err = actor(pipe, buf, &sd); |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 735 | if (err <= 0) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 736 | if (!ret && err != -ENODATA) |
| 737 | ret = err; |
| 738 | |
| 739 | break; |
| 740 | } |
| 741 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 742 | ret += err; |
| 743 | buf->offset += err; |
| 744 | buf->len -= err; |
| 745 | |
| 746 | sd.len -= err; |
| 747 | sd.pos += err; |
| 748 | sd.total_len -= err; |
| 749 | if (sd.len) |
| 750 | continue; |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 751 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 752 | if (!buf->len) { |
| 753 | buf->ops = NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 754 | ops->release(pipe, buf); |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 755 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 756 | pipe->nrbufs--; |
| 757 | if (pipe->inode) |
| 758 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 759 | } |
| 760 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 761 | if (!sd.total_len) |
| 762 | break; |
| 763 | } |
| 764 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 765 | if (pipe->nrbufs) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 766 | continue; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 767 | if (!pipe->writers) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 768 | break; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 769 | if (!pipe->waiting_writers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 770 | if (ret) |
| 771 | break; |
| 772 | } |
| 773 | |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 774 | if (flags & SPLICE_F_NONBLOCK) { |
| 775 | if (!ret) |
| 776 | ret = -EAGAIN; |
| 777 | break; |
| 778 | } |
| 779 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 780 | if (signal_pending(current)) { |
| 781 | if (!ret) |
| 782 | ret = -ERESTARTSYS; |
| 783 | break; |
| 784 | } |
| 785 | |
| 786 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 787 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 788 | if (waitqueue_active(&pipe->wait)) |
| 789 | wake_up_interruptible_sync(&pipe->wait); |
| 790 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 791 | do_wakeup = 0; |
| 792 | } |
| 793 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 794 | pipe_wait(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 795 | } |
| 796 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 797 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 798 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 799 | if (waitqueue_active(&pipe->wait)) |
| 800 | wake_up_interruptible(&pipe->wait); |
| 801 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 802 | } |
| 803 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 804 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 805 | } |
| 806 | |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 807 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 808 | loff_t *ppos, size_t len, unsigned int flags, |
| 809 | splice_actor *actor) |
| 810 | { |
| 811 | ssize_t ret; |
| 812 | struct inode *inode = out->f_mapping->host; |
| 813 | |
| 814 | /* |
| 815 | * The actor worker might be calling ->prepare_write and |
| 816 | * ->commit_write. Most of the time, these expect i_mutex to |
| 817 | * be held. Since this may result in an ABBA deadlock with |
| 818 | * pipe->inode, we have to order lock acquiry here. |
| 819 | */ |
| 820 | inode_double_lock(inode, pipe->inode); |
| 821 | ret = __splice_from_pipe(pipe, out, ppos, len, flags, actor); |
| 822 | inode_double_unlock(inode, pipe->inode); |
| 823 | |
| 824 | return ret; |
| 825 | } |
| 826 | |
| 827 | /** |
| 828 | * generic_file_splice_write_nolock - generic_file_splice_write without mutexes |
| 829 | * @pipe: pipe info |
| 830 | * @out: file to write to |
| 831 | * @len: number of bytes to splice |
| 832 | * @flags: splice modifier flags |
| 833 | * |
| 834 | * Will either move or copy pages (determined by @flags options) from |
| 835 | * the given pipe inode to the given file. The caller is responsible |
| 836 | * for acquiring i_mutex on both inodes. |
| 837 | * |
| 838 | */ |
| 839 | ssize_t |
| 840 | generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, |
| 841 | loff_t *ppos, size_t len, unsigned int flags) |
| 842 | { |
| 843 | struct address_space *mapping = out->f_mapping; |
| 844 | struct inode *inode = mapping->host; |
| 845 | ssize_t ret; |
| 846 | int err; |
| 847 | |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 848 | err = remove_suid(out->f_dentry); |
| 849 | if (unlikely(err)) |
| 850 | return err; |
| 851 | |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 852 | ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
| 853 | if (ret > 0) { |
| 854 | *ppos += ret; |
| 855 | |
| 856 | /* |
| 857 | * If file or inode is SYNC and we actually wrote some data, |
| 858 | * sync it. |
| 859 | */ |
| 860 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 861 | err = generic_osync_inode(inode, mapping, |
| 862 | OSYNC_METADATA|OSYNC_DATA); |
| 863 | |
| 864 | if (err) |
| 865 | ret = err; |
| 866 | } |
| 867 | } |
| 868 | |
| 869 | return ret; |
| 870 | } |
| 871 | |
| 872 | EXPORT_SYMBOL(generic_file_splice_write_nolock); |
| 873 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 874 | /** |
| 875 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 876 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 877 | * @out: file to write to |
| 878 | * @len: number of bytes to splice |
| 879 | * @flags: splice modifier flags |
| 880 | * |
| 881 | * Will either move or copy pages (determined by @flags options) from |
| 882 | * the given pipe inode to the given file. |
| 883 | * |
| 884 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 885 | ssize_t |
| 886 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 887 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 888 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 889 | struct address_space *mapping = out->f_mapping; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 890 | struct inode *inode = mapping->host; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 891 | ssize_t ret; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 892 | int err; |
| 893 | |
| 894 | err = should_remove_suid(out->f_dentry); |
| 895 | if (unlikely(err)) { |
| 896 | mutex_lock(&inode->i_mutex); |
| 897 | err = __remove_suid(out->f_dentry, err); |
| 898 | mutex_unlock(&inode->i_mutex); |
| 899 | if (err) |
| 900 | return err; |
| 901 | } |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 902 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 903 | ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 904 | if (ret > 0) { |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 905 | *ppos += ret; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 906 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 907 | /* |
| 908 | * If file or inode is SYNC and we actually wrote some data, |
| 909 | * sync it. |
| 910 | */ |
| 911 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 912 | mutex_lock(&inode->i_mutex); |
| 913 | err = generic_osync_inode(inode, mapping, |
| 914 | OSYNC_METADATA|OSYNC_DATA); |
| 915 | mutex_unlock(&inode->i_mutex); |
| 916 | |
| 917 | if (err) |
| 918 | ret = err; |
| 919 | } |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 920 | } |
| 921 | |
| 922 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 923 | } |
| 924 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 925 | EXPORT_SYMBOL(generic_file_splice_write); |
| 926 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 927 | /** |
| 928 | * generic_splice_sendpage - splice data from a pipe to a socket |
| 929 | * @inode: pipe inode |
| 930 | * @out: socket to write to |
| 931 | * @len: number of bytes to splice |
| 932 | * @flags: splice modifier flags |
| 933 | * |
| 934 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 935 | * is involved. |
| 936 | * |
| 937 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 938 | 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] | 939 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 940 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 941 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 942 | } |
| 943 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 944 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 945 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 946 | /* |
| 947 | * Attempt to initiate a splice from pipe to file. |
| 948 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 949 | 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] | 950 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 951 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 952 | int ret; |
| 953 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 954 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 955 | return -EINVAL; |
| 956 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 957 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 958 | return -EBADF; |
| 959 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 960 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 961 | if (unlikely(ret < 0)) |
| 962 | return ret; |
| 963 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 964 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 965 | } |
| 966 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 967 | /* |
| 968 | * Attempt to initiate a splice from a file to a pipe. |
| 969 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 970 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 971 | struct pipe_inode_info *pipe, size_t len, |
| 972 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 973 | { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 974 | loff_t isize, left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 975 | int ret; |
| 976 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 977 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 978 | return -EINVAL; |
| 979 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 980 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 981 | return -EBADF; |
| 982 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 983 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 984 | if (unlikely(ret < 0)) |
| 985 | return ret; |
| 986 | |
| 987 | isize = i_size_read(in->f_mapping->host); |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 988 | if (unlikely(*ppos >= isize)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 989 | return 0; |
| 990 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 991 | left = isize - *ppos; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 992 | if (unlikely(left < len)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 993 | len = left; |
| 994 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 995 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 996 | } |
| 997 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 998 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 999 | size_t len, unsigned int flags) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1000 | { |
| 1001 | struct pipe_inode_info *pipe; |
| 1002 | long ret, bytes; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1003 | loff_t out_off; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1004 | umode_t i_mode; |
| 1005 | int i; |
| 1006 | |
| 1007 | /* |
| 1008 | * We require the input being a regular file, as we don't want to |
| 1009 | * randomly drop data for eg socket -> socket splicing. Use the |
| 1010 | * piped splicing for that! |
| 1011 | */ |
| 1012 | i_mode = in->f_dentry->d_inode->i_mode; |
| 1013 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 1014 | return -EINVAL; |
| 1015 | |
| 1016 | /* |
| 1017 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 1018 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 1019 | */ |
| 1020 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1021 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1022 | pipe = alloc_pipe_info(NULL); |
| 1023 | if (!pipe) |
| 1024 | return -ENOMEM; |
| 1025 | |
| 1026 | /* |
| 1027 | * 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] | 1028 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1029 | * PIPE_READERS appropriately. |
| 1030 | */ |
| 1031 | pipe->readers = 1; |
| 1032 | |
| 1033 | current->splice_pipe = pipe; |
| 1034 | } |
| 1035 | |
| 1036 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 1037 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1038 | */ |
| 1039 | ret = 0; |
| 1040 | bytes = 0; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1041 | out_off = 0; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1042 | |
| 1043 | while (len) { |
| 1044 | size_t read_len, max_read_len; |
| 1045 | |
| 1046 | /* |
| 1047 | * Do at most PIPE_BUFFERS pages worth of transfer: |
| 1048 | */ |
| 1049 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); |
| 1050 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1051 | ret = do_splice_to(in, ppos, pipe, max_read_len, flags); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1052 | if (unlikely(ret < 0)) |
| 1053 | goto out_release; |
| 1054 | |
| 1055 | read_len = ret; |
| 1056 | |
| 1057 | /* |
| 1058 | * NOTE: nonblocking mode only applies to the input. We |
| 1059 | * must not do the output in nonblocking mode as then we |
| 1060 | * could get stuck data in the internal pipe: |
| 1061 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1062 | ret = do_splice_from(pipe, out, &out_off, read_len, |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1063 | flags & ~SPLICE_F_NONBLOCK); |
| 1064 | if (unlikely(ret < 0)) |
| 1065 | goto out_release; |
| 1066 | |
| 1067 | bytes += ret; |
| 1068 | len -= ret; |
| 1069 | |
| 1070 | /* |
| 1071 | * In nonblocking mode, if we got back a short read then |
| 1072 | * that was due to either an IO error or due to the |
| 1073 | * pagecache entry not being there. In the IO error case |
| 1074 | * the _next_ splice attempt will produce a clean IO error |
| 1075 | * return value (not a short read), so in both cases it's |
| 1076 | * correct to break out of the loop here: |
| 1077 | */ |
| 1078 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) |
| 1079 | break; |
| 1080 | } |
| 1081 | |
| 1082 | pipe->nrbufs = pipe->curbuf = 0; |
| 1083 | |
| 1084 | return bytes; |
| 1085 | |
| 1086 | out_release: |
| 1087 | /* |
| 1088 | * If we did an incomplete transfer we must release |
| 1089 | * the pipe buffers in question: |
| 1090 | */ |
| 1091 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1092 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1093 | |
| 1094 | if (buf->ops) { |
| 1095 | buf->ops->release(pipe, buf); |
| 1096 | buf->ops = NULL; |
| 1097 | } |
| 1098 | } |
| 1099 | pipe->nrbufs = pipe->curbuf = 0; |
| 1100 | |
| 1101 | /* |
| 1102 | * If we transferred some data, return the number of bytes: |
| 1103 | */ |
| 1104 | if (bytes > 0) |
| 1105 | return bytes; |
| 1106 | |
| 1107 | return ret; |
| 1108 | } |
| 1109 | |
| 1110 | EXPORT_SYMBOL(do_splice_direct); |
| 1111 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1112 | /* |
| 1113 | * Determine where to splice to/from. |
| 1114 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1115 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1116 | struct file *out, loff_t __user *off_out, |
| 1117 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1118 | { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1119 | struct pipe_inode_info *pipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1120 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1121 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1122 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1123 | pipe = in->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1124 | if (pipe) { |
| 1125 | if (off_in) |
| 1126 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1127 | if (off_out) { |
| 1128 | if (out->f_op->llseek == no_llseek) |
| 1129 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1130 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1131 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1132 | off = &offset; |
| 1133 | } else |
| 1134 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1135 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1136 | ret = do_splice_from(pipe, out, off, len, flags); |
| 1137 | |
| 1138 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1139 | ret = -EFAULT; |
| 1140 | |
| 1141 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1142 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1143 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1144 | pipe = out->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1145 | if (pipe) { |
| 1146 | if (off_out) |
| 1147 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1148 | if (off_in) { |
| 1149 | if (in->f_op->llseek == no_llseek) |
| 1150 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1151 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1152 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1153 | off = &offset; |
| 1154 | } else |
| 1155 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1156 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1157 | ret = do_splice_to(in, off, pipe, len, flags); |
| 1158 | |
| 1159 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1160 | ret = -EFAULT; |
| 1161 | |
| 1162 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1163 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1164 | |
| 1165 | return -EINVAL; |
| 1166 | } |
| 1167 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1168 | /* |
| 1169 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1170 | * partial_page structure, we can map several non-contiguous ranges into |
| 1171 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1172 | * Could easily be exported as a generic helper for other users, in which |
| 1173 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1174 | */ |
| 1175 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1176 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1177 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1178 | { |
| 1179 | int buffers = 0, error = 0; |
| 1180 | |
| 1181 | /* |
| 1182 | * It's ok to take the mmap_sem for reading, even |
| 1183 | * across a "get_user()". |
| 1184 | */ |
| 1185 | down_read(¤t->mm->mmap_sem); |
| 1186 | |
| 1187 | while (nr_vecs) { |
| 1188 | unsigned long off, npages; |
| 1189 | void __user *base; |
| 1190 | size_t len; |
| 1191 | int i; |
| 1192 | |
| 1193 | /* |
| 1194 | * Get user address base and length for this iovec. |
| 1195 | */ |
| 1196 | error = get_user(base, &iov->iov_base); |
| 1197 | if (unlikely(error)) |
| 1198 | break; |
| 1199 | error = get_user(len, &iov->iov_len); |
| 1200 | if (unlikely(error)) |
| 1201 | break; |
| 1202 | |
| 1203 | /* |
| 1204 | * Sanity check this iovec. 0 read succeeds. |
| 1205 | */ |
| 1206 | if (unlikely(!len)) |
| 1207 | break; |
| 1208 | error = -EFAULT; |
| 1209 | if (unlikely(!base)) |
| 1210 | break; |
| 1211 | |
| 1212 | /* |
| 1213 | * Get this base offset and number of pages, then map |
| 1214 | * in the user pages. |
| 1215 | */ |
| 1216 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1217 | |
| 1218 | /* |
| 1219 | * If asked for alignment, the offset must be zero and the |
| 1220 | * length a multiple of the PAGE_SIZE. |
| 1221 | */ |
| 1222 | error = -EINVAL; |
| 1223 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1224 | break; |
| 1225 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1226 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1227 | if (npages > PIPE_BUFFERS - buffers) |
| 1228 | npages = PIPE_BUFFERS - buffers; |
| 1229 | |
| 1230 | error = get_user_pages(current, current->mm, |
| 1231 | (unsigned long) base, npages, 0, 0, |
| 1232 | &pages[buffers], NULL); |
| 1233 | |
| 1234 | if (unlikely(error <= 0)) |
| 1235 | break; |
| 1236 | |
| 1237 | /* |
| 1238 | * Fill this contiguous range into the partial page map. |
| 1239 | */ |
| 1240 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1241 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1242 | |
| 1243 | partial[buffers].offset = off; |
| 1244 | partial[buffers].len = plen; |
| 1245 | |
| 1246 | off = 0; |
| 1247 | len -= plen; |
| 1248 | buffers++; |
| 1249 | } |
| 1250 | |
| 1251 | /* |
| 1252 | * We didn't complete this iov, stop here since it probably |
| 1253 | * means we have to move some of this into a pipe to |
| 1254 | * be able to continue. |
| 1255 | */ |
| 1256 | if (len) |
| 1257 | break; |
| 1258 | |
| 1259 | /* |
| 1260 | * Don't continue if we mapped fewer pages than we asked for, |
| 1261 | * or if we mapped the max number of pages that we have |
| 1262 | * room for. |
| 1263 | */ |
| 1264 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1265 | break; |
| 1266 | |
| 1267 | nr_vecs--; |
| 1268 | iov++; |
| 1269 | } |
| 1270 | |
| 1271 | up_read(¤t->mm->mmap_sem); |
| 1272 | |
| 1273 | if (buffers) |
| 1274 | return buffers; |
| 1275 | |
| 1276 | return error; |
| 1277 | } |
| 1278 | |
| 1279 | /* |
| 1280 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1281 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1282 | * to file). In both cases the output is a pipe, naturally. |
| 1283 | * |
| 1284 | * Note that vmsplice only supports splicing _from_ user memory to a pipe, |
| 1285 | * not the other way around. Splicing from user memory is a simple operation |
| 1286 | * that can be supported without any funky alignment restrictions or nasty |
| 1287 | * vm tricks. We simply map in the user memory and fill them into a pipe. |
| 1288 | * The reverse isn't quite as easy, though. There are two possible solutions |
| 1289 | * for that: |
| 1290 | * |
| 1291 | * - memcpy() the data internally, at which point we might as well just |
| 1292 | * do a regular read() on the buffer anyway. |
| 1293 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1294 | * has restriction limitations on both ends of the pipe). |
| 1295 | * |
| 1296 | * Alas, it isn't here. |
| 1297 | * |
| 1298 | */ |
| 1299 | static long do_vmsplice(struct file *file, const struct iovec __user *iov, |
| 1300 | unsigned long nr_segs, unsigned int flags) |
| 1301 | { |
| 1302 | struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe; |
| 1303 | struct page *pages[PIPE_BUFFERS]; |
| 1304 | struct partial_page partial[PIPE_BUFFERS]; |
| 1305 | struct splice_pipe_desc spd = { |
| 1306 | .pages = pages, |
| 1307 | .partial = partial, |
| 1308 | .flags = flags, |
| 1309 | .ops = &user_page_pipe_buf_ops, |
| 1310 | }; |
| 1311 | |
| 1312 | if (unlikely(!pipe)) |
| 1313 | return -EBADF; |
| 1314 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1315 | return -EINVAL; |
| 1316 | else if (unlikely(!nr_segs)) |
| 1317 | return 0; |
| 1318 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1319 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1320 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1321 | if (spd.nr_pages <= 0) |
| 1322 | return spd.nr_pages; |
| 1323 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1324 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1325 | } |
| 1326 | |
| 1327 | asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, |
| 1328 | unsigned long nr_segs, unsigned int flags) |
| 1329 | { |
| 1330 | struct file *file; |
| 1331 | long error; |
| 1332 | int fput; |
| 1333 | |
| 1334 | error = -EBADF; |
| 1335 | file = fget_light(fd, &fput); |
| 1336 | if (file) { |
| 1337 | if (file->f_mode & FMODE_WRITE) |
| 1338 | error = do_vmsplice(file, iov, nr_segs, flags); |
| 1339 | |
| 1340 | fput_light(file, fput); |
| 1341 | } |
| 1342 | |
| 1343 | return error; |
| 1344 | } |
| 1345 | |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1346 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
| 1347 | int fd_out, loff_t __user *off_out, |
| 1348 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1349 | { |
| 1350 | long error; |
| 1351 | struct file *in, *out; |
| 1352 | int fput_in, fput_out; |
| 1353 | |
| 1354 | if (unlikely(!len)) |
| 1355 | return 0; |
| 1356 | |
| 1357 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1358 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1359 | if (in) { |
| 1360 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1361 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1362 | if (out) { |
| 1363 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1364 | error = do_splice(in, off_in, |
| 1365 | out, off_out, |
| 1366 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1367 | fput_light(out, fput_out); |
| 1368 | } |
| 1369 | } |
| 1370 | |
| 1371 | fput_light(in, fput_in); |
| 1372 | } |
| 1373 | |
| 1374 | return error; |
| 1375 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1376 | |
| 1377 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1378 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1379 | * return an appropriate error. |
| 1380 | */ |
| 1381 | static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1382 | { |
| 1383 | int ret; |
| 1384 | |
| 1385 | /* |
| 1386 | * Check ->nrbufs without the inode lock first. This function |
| 1387 | * is speculative anyways, so missing one is ok. |
| 1388 | */ |
| 1389 | if (pipe->nrbufs) |
| 1390 | return 0; |
| 1391 | |
| 1392 | ret = 0; |
| 1393 | mutex_lock(&pipe->inode->i_mutex); |
| 1394 | |
| 1395 | while (!pipe->nrbufs) { |
| 1396 | if (signal_pending(current)) { |
| 1397 | ret = -ERESTARTSYS; |
| 1398 | break; |
| 1399 | } |
| 1400 | if (!pipe->writers) |
| 1401 | break; |
| 1402 | if (!pipe->waiting_writers) { |
| 1403 | if (flags & SPLICE_F_NONBLOCK) { |
| 1404 | ret = -EAGAIN; |
| 1405 | break; |
| 1406 | } |
| 1407 | } |
| 1408 | pipe_wait(pipe); |
| 1409 | } |
| 1410 | |
| 1411 | mutex_unlock(&pipe->inode->i_mutex); |
| 1412 | return ret; |
| 1413 | } |
| 1414 | |
| 1415 | /* |
| 1416 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1417 | * return an appropriate error. |
| 1418 | */ |
| 1419 | static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1420 | { |
| 1421 | int ret; |
| 1422 | |
| 1423 | /* |
| 1424 | * Check ->nrbufs without the inode lock first. This function |
| 1425 | * is speculative anyways, so missing one is ok. |
| 1426 | */ |
| 1427 | if (pipe->nrbufs < PIPE_BUFFERS) |
| 1428 | return 0; |
| 1429 | |
| 1430 | ret = 0; |
| 1431 | mutex_lock(&pipe->inode->i_mutex); |
| 1432 | |
| 1433 | while (pipe->nrbufs >= PIPE_BUFFERS) { |
| 1434 | if (!pipe->readers) { |
| 1435 | send_sig(SIGPIPE, current, 0); |
| 1436 | ret = -EPIPE; |
| 1437 | break; |
| 1438 | } |
| 1439 | if (flags & SPLICE_F_NONBLOCK) { |
| 1440 | ret = -EAGAIN; |
| 1441 | break; |
| 1442 | } |
| 1443 | if (signal_pending(current)) { |
| 1444 | ret = -ERESTARTSYS; |
| 1445 | break; |
| 1446 | } |
| 1447 | pipe->waiting_writers++; |
| 1448 | pipe_wait(pipe); |
| 1449 | pipe->waiting_writers--; |
| 1450 | } |
| 1451 | |
| 1452 | mutex_unlock(&pipe->inode->i_mutex); |
| 1453 | return ret; |
| 1454 | } |
| 1455 | |
| 1456 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1457 | * Link contents of ipipe to opipe. |
| 1458 | */ |
| 1459 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1460 | struct pipe_inode_info *opipe, |
| 1461 | size_t len, unsigned int flags) |
| 1462 | { |
| 1463 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1464 | int ret = 0, i = 0, nbuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1465 | |
| 1466 | /* |
| 1467 | * Potential ABBA deadlock, work around it by ordering lock |
| 1468 | * grabbing by inode address. Otherwise two different processes |
| 1469 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1470 | */ |
Mark Fasheh | 62752ee | 2006-10-17 10:31:38 +0200 | [diff] [blame] | 1471 | inode_double_lock(ipipe->inode, opipe->inode); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1472 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1473 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1474 | if (!opipe->readers) { |
| 1475 | send_sig(SIGPIPE, current, 0); |
| 1476 | if (!ret) |
| 1477 | ret = -EPIPE; |
| 1478 | break; |
| 1479 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1480 | |
| 1481 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1482 | * If we have iterated all input buffers or ran out of |
| 1483 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1484 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1485 | if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1486 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1487 | |
| 1488 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1489 | nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1490 | |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1491 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1492 | * Get a reference to this pipe buffer, |
| 1493 | * so we can copy the contents over. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1494 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1495 | ibuf->ops->get(ipipe, ibuf); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1496 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1497 | obuf = opipe->bufs + nbuf; |
| 1498 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1499 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1500 | /* |
| 1501 | * Don't inherit the gift flag, we need to |
| 1502 | * prevent multiple steals of this page. |
| 1503 | */ |
| 1504 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1505 | |
| 1506 | if (obuf->len > len) |
| 1507 | obuf->len = len; |
| 1508 | |
| 1509 | opipe->nrbufs++; |
| 1510 | ret += obuf->len; |
| 1511 | len -= obuf->len; |
| 1512 | i++; |
| 1513 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1514 | |
Mark Fasheh | 62752ee | 2006-10-17 10:31:38 +0200 | [diff] [blame] | 1515 | inode_double_unlock(ipipe->inode, opipe->inode); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1516 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1517 | /* |
| 1518 | * If we put data in the output pipe, wakeup any potential readers. |
| 1519 | */ |
| 1520 | if (ret > 0) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1521 | smp_mb(); |
| 1522 | if (waitqueue_active(&opipe->wait)) |
| 1523 | wake_up_interruptible(&opipe->wait); |
| 1524 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1525 | } |
| 1526 | |
| 1527 | return ret; |
| 1528 | } |
| 1529 | |
| 1530 | /* |
| 1531 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1532 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1533 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1534 | * applicable one is SPLICE_F_NONBLOCK. |
| 1535 | */ |
| 1536 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1537 | unsigned int flags) |
| 1538 | { |
| 1539 | struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe; |
| 1540 | struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1541 | int ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1542 | |
| 1543 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1544 | * Duplicate the contents of ipipe to opipe without actually |
| 1545 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1546 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1547 | if (ipipe && opipe && ipipe != opipe) { |
| 1548 | /* |
| 1549 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1550 | * ordering doesn't really matter. |
| 1551 | */ |
| 1552 | ret = link_ipipe_prep(ipipe, flags); |
| 1553 | if (!ret) { |
| 1554 | ret = link_opipe_prep(opipe, flags); |
| 1555 | if (!ret) { |
| 1556 | ret = link_pipe(ipipe, opipe, len, flags); |
| 1557 | if (!ret && (flags & SPLICE_F_NONBLOCK)) |
| 1558 | ret = -EAGAIN; |
| 1559 | } |
| 1560 | } |
| 1561 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1562 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1563 | return ret; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1564 | } |
| 1565 | |
| 1566 | asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) |
| 1567 | { |
| 1568 | struct file *in; |
| 1569 | int error, fput_in; |
| 1570 | |
| 1571 | if (unlikely(!len)) |
| 1572 | return 0; |
| 1573 | |
| 1574 | error = -EBADF; |
| 1575 | in = fget_light(fdin, &fput_in); |
| 1576 | if (in) { |
| 1577 | if (in->f_mode & FMODE_READ) { |
| 1578 | int fput_out; |
| 1579 | struct file *out = fget_light(fdout, &fput_out); |
| 1580 | |
| 1581 | if (out) { |
| 1582 | if (out->f_mode & FMODE_WRITE) |
| 1583 | error = do_tee(in, out, len, flags); |
| 1584 | fput_light(out, fput_out); |
| 1585 | } |
| 1586 | } |
| 1587 | fput_light(in, fput_in); |
| 1588 | } |
| 1589 | |
| 1590 | return error; |
| 1591 | } |