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 | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 30 | |
| 31 | /* |
| 32 | * Passed to the actors |
| 33 | */ |
| 34 | struct splice_desc { |
| 35 | unsigned int len, total_len; /* current and remaining length */ |
| 36 | unsigned int flags; /* splice flags */ |
| 37 | struct file *file; /* file to read/write */ |
| 38 | loff_t pos; /* file position */ |
| 39 | }; |
| 40 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 41 | /* |
| 42 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 43 | * a vm helper function, it's already simplified quite a bit by the |
| 44 | * addition of remove_mapping(). If success is returned, the caller may |
| 45 | * attempt to reuse this page for another destination. |
| 46 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 47 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, |
| 48 | struct pipe_buffer *buf) |
| 49 | { |
| 50 | struct page *page = buf->page; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 51 | struct address_space *mapping = page_mapping(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 52 | |
| 53 | WARN_ON(!PageLocked(page)); |
| 54 | WARN_ON(!PageUptodate(page)); |
| 55 | |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 56 | /* |
| 57 | * At least for ext2 with nobh option, we need to wait on writeback |
| 58 | * completing on this page, since we'll remove it from the pagecache. |
| 59 | * Otherwise truncate wont wait on the page, allowing the disk |
| 60 | * blocks to be reused by someone else before we actually wrote our |
| 61 | * data to them. fs corruption ensues. |
| 62 | */ |
| 63 | wait_on_page_writeback(page); |
| 64 | |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 65 | if (PagePrivate(page)) |
| 66 | try_to_release_page(page, mapping_gfp_mask(mapping)); |
| 67 | |
| 68 | if (!remove_mapping(mapping, page)) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 69 | return 1; |
| 70 | |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 71 | buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 72 | return 0; |
| 73 | } |
| 74 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 75 | static void page_cache_pipe_buf_release(struct pipe_inode_info *info, |
| 76 | struct pipe_buffer *buf) |
| 77 | { |
| 78 | page_cache_release(buf->page); |
| 79 | buf->page = NULL; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 80 | buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 81 | } |
| 82 | |
| 83 | static void *page_cache_pipe_buf_map(struct file *file, |
| 84 | struct pipe_inode_info *info, |
| 85 | struct pipe_buffer *buf) |
| 86 | { |
| 87 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 88 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 89 | |
| 90 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 91 | lock_page(page); |
| 92 | |
| 93 | /* |
| 94 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 95 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 96 | */ |
| 97 | if (!page->mapping) { |
| 98 | err = -ENODATA; |
| 99 | goto error; |
| 100 | } |
| 101 | |
| 102 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 103 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 104 | */ |
| 105 | if (!PageUptodate(page)) { |
| 106 | err = -EIO; |
| 107 | goto error; |
| 108 | } |
| 109 | |
| 110 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 111 | * Page is ok afterall, fall through to mapping. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 112 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 113 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 114 | } |
| 115 | |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 116 | return kmap(page); |
| 117 | error: |
| 118 | unlock_page(page); |
| 119 | return ERR_PTR(err); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 120 | } |
| 121 | |
| 122 | static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, |
| 123 | struct pipe_buffer *buf) |
| 124 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 125 | kunmap(buf->page); |
| 126 | } |
| 127 | |
| 128 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { |
| 129 | .can_merge = 0, |
| 130 | .map = page_cache_pipe_buf_map, |
| 131 | .unmap = page_cache_pipe_buf_unmap, |
| 132 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 133 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 134 | }; |
| 135 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 136 | /* |
| 137 | * Pipe output worker. This sets up our pipe format with the page cache |
| 138 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). |
| 139 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 140 | static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 141 | int nr_pages, unsigned long offset, |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 142 | unsigned long len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 143 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 144 | int ret, do_wakeup, i; |
| 145 | |
| 146 | ret = 0; |
| 147 | do_wakeup = 0; |
| 148 | i = 0; |
| 149 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 150 | if (pipe->inode) |
| 151 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 152 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 153 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 154 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 155 | send_sig(SIGPIPE, current, 0); |
| 156 | if (!ret) |
| 157 | ret = -EPIPE; |
| 158 | break; |
| 159 | } |
| 160 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 161 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 162 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 163 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 164 | struct page *page = pages[i++]; |
| 165 | unsigned long this_len; |
| 166 | |
| 167 | this_len = PAGE_CACHE_SIZE - offset; |
| 168 | if (this_len > len) |
| 169 | this_len = len; |
| 170 | |
| 171 | buf->page = page; |
| 172 | buf->offset = offset; |
| 173 | buf->len = this_len; |
| 174 | buf->ops = &page_cache_pipe_buf_ops; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 175 | pipe->nrbufs++; |
| 176 | if (pipe->inode) |
| 177 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 178 | |
| 179 | ret += this_len; |
| 180 | len -= this_len; |
| 181 | offset = 0; |
| 182 | if (!--nr_pages) |
| 183 | break; |
| 184 | if (!len) |
| 185 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 186 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 187 | continue; |
| 188 | |
| 189 | break; |
| 190 | } |
| 191 | |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 192 | if (flags & SPLICE_F_NONBLOCK) { |
| 193 | if (!ret) |
| 194 | ret = -EAGAIN; |
| 195 | break; |
| 196 | } |
| 197 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 198 | if (signal_pending(current)) { |
| 199 | if (!ret) |
| 200 | ret = -ERESTARTSYS; |
| 201 | break; |
| 202 | } |
| 203 | |
| 204 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 205 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 206 | if (waitqueue_active(&pipe->wait)) |
| 207 | wake_up_interruptible_sync(&pipe->wait); |
| 208 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 209 | do_wakeup = 0; |
| 210 | } |
| 211 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 212 | pipe->waiting_writers++; |
| 213 | pipe_wait(pipe); |
| 214 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 215 | } |
| 216 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 217 | if (pipe->inode) |
| 218 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 219 | |
| 220 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 221 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 222 | if (waitqueue_active(&pipe->wait)) |
| 223 | wake_up_interruptible(&pipe->wait); |
| 224 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 225 | } |
| 226 | |
| 227 | while (i < nr_pages) |
| 228 | page_cache_release(pages[i++]); |
| 229 | |
| 230 | return ret; |
| 231 | } |
| 232 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 233 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 234 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 235 | struct pipe_inode_info *pipe, size_t len, |
| 236 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 237 | { |
| 238 | struct address_space *mapping = in->f_mapping; |
| 239 | unsigned int offset, nr_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 240 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 241 | struct page *page; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 242 | pgoff_t index; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 243 | int i, error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 244 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 245 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 246 | offset = *ppos & ~PAGE_CACHE_MASK; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 247 | nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 248 | |
| 249 | if (nr_pages > PIPE_BUFFERS) |
| 250 | nr_pages = PIPE_BUFFERS; |
| 251 | |
| 252 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 253 | * Initiate read-ahead on this page range. however, don't call into |
Jens Axboe | 0b749ce | 2006-04-10 09:05:04 +0200 | [diff] [blame] | 254 | * read-ahead if this is a non-zero offset (we are likely doing small |
| 255 | * chunk splice and the page is already there) for a single page. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 256 | */ |
Jens Axboe | 0b749ce | 2006-04-10 09:05:04 +0200 | [diff] [blame] | 257 | if (!offset || nr_pages > 1) |
| 258 | do_page_cache_readahead(mapping, in, index, nr_pages); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 259 | |
| 260 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 261 | * Now fill in the holes: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 262 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 263 | error = 0; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 264 | for (i = 0; i < nr_pages; i++, index++) { |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 265 | find_page: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 266 | /* |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 267 | * lookup the page for this index |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 268 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 269 | page = find_get_page(mapping, index); |
| 270 | if (!page) { |
| 271 | /* |
| 272 | * If in nonblock mode then dont block on |
| 273 | * readpage (we've kicked readahead so there |
| 274 | * will be asynchronous progress): |
| 275 | */ |
| 276 | if (flags & SPLICE_F_NONBLOCK) |
| 277 | break; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 278 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 279 | /* |
| 280 | * page didn't exist, allocate one |
| 281 | */ |
| 282 | page = page_cache_alloc_cold(mapping); |
| 283 | if (!page) |
| 284 | break; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 285 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 286 | error = add_to_page_cache_lru(page, mapping, index, |
| 287 | mapping_gfp_mask(mapping)); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 288 | if (unlikely(error)) { |
| 289 | page_cache_release(page); |
| 290 | break; |
| 291 | } |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 292 | |
| 293 | goto readpage; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 294 | } |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 295 | |
| 296 | /* |
| 297 | * If the page isn't uptodate, we may need to start io on it |
| 298 | */ |
| 299 | if (!PageUptodate(page)) { |
| 300 | lock_page(page); |
| 301 | |
| 302 | /* |
| 303 | * page was truncated, stop here. if this isn't the |
| 304 | * first page, we'll just complete what we already |
| 305 | * added |
| 306 | */ |
| 307 | if (!page->mapping) { |
| 308 | unlock_page(page); |
| 309 | page_cache_release(page); |
| 310 | break; |
| 311 | } |
| 312 | /* |
| 313 | * page was already under io and is now done, great |
| 314 | */ |
| 315 | if (PageUptodate(page)) { |
| 316 | unlock_page(page); |
| 317 | goto fill_it; |
| 318 | } |
| 319 | |
| 320 | readpage: |
| 321 | /* |
| 322 | * need to read in the page |
| 323 | */ |
| 324 | error = mapping->a_ops->readpage(in, page); |
| 325 | |
| 326 | if (unlikely(error)) { |
| 327 | page_cache_release(page); |
| 328 | if (error == AOP_TRUNCATED_PAGE) |
| 329 | goto find_page; |
| 330 | break; |
| 331 | } |
| 332 | } |
| 333 | fill_it: |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 334 | pages[i] = page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 335 | } |
| 336 | |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 337 | if (i) |
| 338 | return move_to_pipe(pipe, pages, i, offset, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 339 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 340 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 341 | } |
| 342 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 343 | /** |
| 344 | * generic_file_splice_read - splice data from file to a pipe |
| 345 | * @in: file to splice from |
| 346 | * @pipe: pipe to splice to |
| 347 | * @len: number of bytes to splice |
| 348 | * @flags: splice modifier flags |
| 349 | * |
| 350 | * Will read pages from given file and fill them into a pipe. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 351 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 352 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 353 | struct pipe_inode_info *pipe, size_t len, |
| 354 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 355 | { |
| 356 | ssize_t spliced; |
| 357 | int ret; |
| 358 | |
| 359 | ret = 0; |
| 360 | spliced = 0; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 361 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 362 | while (len) { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 363 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 364 | |
| 365 | if (ret <= 0) |
| 366 | break; |
| 367 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 368 | *ppos += ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 369 | len -= ret; |
| 370 | spliced += ret; |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 371 | |
| 372 | if (!(flags & SPLICE_F_NONBLOCK)) |
| 373 | continue; |
| 374 | ret = -EAGAIN; |
| 375 | break; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 376 | } |
| 377 | |
| 378 | if (spliced) |
| 379 | return spliced; |
| 380 | |
| 381 | return ret; |
| 382 | } |
| 383 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 384 | EXPORT_SYMBOL(generic_file_splice_read); |
| 385 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 386 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 387 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
| 388 | * using sendpage(). |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 389 | */ |
| 390 | static int pipe_to_sendpage(struct pipe_inode_info *info, |
| 391 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 392 | { |
| 393 | struct file *file = sd->file; |
| 394 | loff_t pos = sd->pos; |
| 395 | unsigned int offset; |
| 396 | ssize_t ret; |
| 397 | void *ptr; |
Jens Axboe | b2b39fa | 2006-04-02 23:05:41 +0200 | [diff] [blame] | 398 | int more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 399 | |
| 400 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 401 | * Sub-optimal, but we are limited by the pipe ->map. We don't |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 402 | * need a kmap'ed buffer here, we just want to make sure we |
| 403 | * have the page pinned if the pipe page originates from the |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 404 | * page cache. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 405 | */ |
| 406 | ptr = buf->ops->map(file, info, buf); |
| 407 | if (IS_ERR(ptr)) |
| 408 | return PTR_ERR(ptr); |
| 409 | |
| 410 | offset = pos & ~PAGE_CACHE_MASK; |
Jens Axboe | b2b39fa | 2006-04-02 23:05:41 +0200 | [diff] [blame] | 411 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 412 | |
Jens Axboe | b2b39fa | 2006-04-02 23:05:41 +0200 | [diff] [blame] | 413 | ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 414 | |
| 415 | buf->ops->unmap(info, buf); |
| 416 | if (ret == sd->len) |
| 417 | return 0; |
| 418 | |
| 419 | return -EIO; |
| 420 | } |
| 421 | |
| 422 | /* |
| 423 | * This is a little more tricky than the file -> pipe splicing. There are |
| 424 | * basically three cases: |
| 425 | * |
| 426 | * - Destination page already exists in the address space and there |
| 427 | * are users of it. For that case we have no other option that |
| 428 | * copying the data. Tough luck. |
| 429 | * - Destination page already exists in the address space, but there |
| 430 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 431 | * through to last case. |
| 432 | * - Destination page does not exist, we can add the pipe page to |
| 433 | * the page cache and avoid the copy. |
| 434 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 435 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 436 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 437 | * file address space page cache. This is possible if no one else has |
| 438 | * the pipe page referenced outside of the pipe and page cache. If |
| 439 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 440 | * 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] | 441 | */ |
| 442 | static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, |
| 443 | struct splice_desc *sd) |
| 444 | { |
| 445 | struct file *file = sd->file; |
| 446 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 447 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 448 | unsigned int offset; |
| 449 | struct page *page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 450 | pgoff_t index; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 451 | char *src; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 452 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 453 | |
| 454 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 455 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 456 | */ |
| 457 | src = buf->ops->map(file, info, buf); |
| 458 | if (IS_ERR(src)) |
| 459 | return PTR_ERR(src); |
| 460 | |
| 461 | index = sd->pos >> PAGE_CACHE_SHIFT; |
| 462 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 463 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 464 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 465 | * Reuse buf page, if SPLICE_F_MOVE is set. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 466 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 467 | if (sd->flags & SPLICE_F_MOVE) { |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 468 | /* |
| 469 | * If steal succeeds, buf->page is now pruned from the vm |
| 470 | * side (LRU and page cache) and we can reuse it. |
| 471 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 472 | if (buf->ops->steal(info, buf)) |
| 473 | goto find_page; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 474 | |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 475 | /* |
| 476 | * this will also set the page locked |
| 477 | */ |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 478 | page = buf->page; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 479 | if (add_to_page_cache(page, mapping, index, gfp_mask)) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 480 | goto find_page; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 481 | |
| 482 | if (!(buf->flags & PIPE_BUF_FLAG_LRU)) |
| 483 | lru_cache_add(page); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 484 | } else { |
| 485 | find_page: |
| 486 | ret = -ENOMEM; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 487 | page = find_or_create_page(mapping, index, gfp_mask); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 488 | if (!page) |
Dave Jones | 9aefe43 | 2006-04-10 09:02:40 +0200 | [diff] [blame] | 489 | goto out_nomem; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 490 | |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 491 | /* |
| 492 | * If the page is uptodate, it is also locked. If it isn't |
| 493 | * uptodate, we can mark it uptodate if we are filling the |
| 494 | * full page. Otherwise we need to read it in first... |
| 495 | */ |
| 496 | if (!PageUptodate(page)) { |
| 497 | if (sd->len < PAGE_CACHE_SIZE) { |
| 498 | ret = mapping->a_ops->readpage(file, page); |
| 499 | if (unlikely(ret)) |
| 500 | goto out; |
| 501 | |
| 502 | lock_page(page); |
| 503 | |
| 504 | if (!PageUptodate(page)) { |
| 505 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 506 | * Page got invalidated, repeat. |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 507 | */ |
| 508 | if (!page->mapping) { |
| 509 | unlock_page(page); |
| 510 | page_cache_release(page); |
| 511 | goto find_page; |
| 512 | } |
| 513 | ret = -EIO; |
| 514 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 515 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 516 | } else { |
| 517 | WARN_ON(!PageLocked(page)); |
| 518 | SetPageUptodate(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 519 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 520 | } |
| 521 | } |
| 522 | |
| 523 | ret = mapping->a_ops->prepare_write(file, page, 0, sd->len); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 524 | if (ret == AOP_TRUNCATED_PAGE) { |
| 525 | page_cache_release(page); |
| 526 | goto find_page; |
| 527 | } else if (ret) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 528 | goto out; |
| 529 | |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 530 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 531 | char *dst = kmap_atomic(page, KM_USER0); |
| 532 | |
| 533 | memcpy(dst + offset, src + buf->offset, sd->len); |
| 534 | flush_dcache_page(page); |
| 535 | kunmap_atomic(dst, KM_USER0); |
| 536 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 537 | |
| 538 | ret = mapping->a_ops->commit_write(file, page, 0, sd->len); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 539 | if (ret == AOP_TRUNCATED_PAGE) { |
| 540 | page_cache_release(page); |
| 541 | goto find_page; |
| 542 | } else if (ret) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 543 | goto out; |
| 544 | |
Jens Axboe | c7f21e4 | 2006-04-10 09:01:01 +0200 | [diff] [blame] | 545 | mark_page_accessed(page); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 546 | balance_dirty_pages_ratelimited(mapping); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 547 | out: |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 548 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 549 | page_cache_release(page); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 550 | unlock_page(page); |
| 551 | } |
Dave Jones | 9aefe43 | 2006-04-10 09:02:40 +0200 | [diff] [blame] | 552 | out_nomem: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 553 | buf->ops->unmap(info, buf); |
| 554 | return ret; |
| 555 | } |
| 556 | |
| 557 | typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, |
| 558 | struct splice_desc *); |
| 559 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 560 | /* |
| 561 | * Pipe input worker. Most of this logic works like a regular pipe, the |
| 562 | * key here is the 'actor' worker passed in that actually moves the data |
| 563 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. |
| 564 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 565 | static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 566 | loff_t *ppos, size_t len, unsigned int flags, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 567 | splice_actor *actor) |
| 568 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 569 | int ret, do_wakeup, err; |
| 570 | struct splice_desc sd; |
| 571 | |
| 572 | ret = 0; |
| 573 | do_wakeup = 0; |
| 574 | |
| 575 | sd.total_len = len; |
| 576 | sd.flags = flags; |
| 577 | sd.file = out; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 578 | sd.pos = *ppos; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 579 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 580 | if (pipe->inode) |
| 581 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 582 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 583 | for (;;) { |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 584 | if (pipe->nrbufs) { |
| 585 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 586 | struct pipe_buf_operations *ops = buf->ops; |
| 587 | |
| 588 | sd.len = buf->len; |
| 589 | if (sd.len > sd.total_len) |
| 590 | sd.len = sd.total_len; |
| 591 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 592 | err = actor(pipe, buf, &sd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 593 | if (err) { |
| 594 | if (!ret && err != -ENODATA) |
| 595 | ret = err; |
| 596 | |
| 597 | break; |
| 598 | } |
| 599 | |
| 600 | ret += sd.len; |
| 601 | buf->offset += sd.len; |
| 602 | buf->len -= sd.len; |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 603 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 604 | if (!buf->len) { |
| 605 | buf->ops = NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 606 | ops->release(pipe, buf); |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 607 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 608 | pipe->nrbufs--; |
| 609 | if (pipe->inode) |
| 610 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 611 | } |
| 612 | |
| 613 | sd.pos += sd.len; |
| 614 | sd.total_len -= sd.len; |
| 615 | if (!sd.total_len) |
| 616 | break; |
| 617 | } |
| 618 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 619 | if (pipe->nrbufs) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 620 | continue; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 621 | if (!pipe->writers) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 622 | break; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 623 | if (!pipe->waiting_writers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 624 | if (ret) |
| 625 | break; |
| 626 | } |
| 627 | |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 628 | if (flags & SPLICE_F_NONBLOCK) { |
| 629 | if (!ret) |
| 630 | ret = -EAGAIN; |
| 631 | break; |
| 632 | } |
| 633 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 634 | if (signal_pending(current)) { |
| 635 | if (!ret) |
| 636 | ret = -ERESTARTSYS; |
| 637 | break; |
| 638 | } |
| 639 | |
| 640 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 641 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 642 | if (waitqueue_active(&pipe->wait)) |
| 643 | wake_up_interruptible_sync(&pipe->wait); |
| 644 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 645 | do_wakeup = 0; |
| 646 | } |
| 647 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 648 | pipe_wait(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 649 | } |
| 650 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 651 | if (pipe->inode) |
| 652 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 653 | |
| 654 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 655 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 656 | if (waitqueue_active(&pipe->wait)) |
| 657 | wake_up_interruptible(&pipe->wait); |
| 658 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 659 | } |
| 660 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 661 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 662 | } |
| 663 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 664 | /** |
| 665 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 666 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 667 | * @out: file to write to |
| 668 | * @len: number of bytes to splice |
| 669 | * @flags: splice modifier flags |
| 670 | * |
| 671 | * Will either move or copy pages (determined by @flags options) from |
| 672 | * the given pipe inode to the given file. |
| 673 | * |
| 674 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 675 | ssize_t |
| 676 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 677 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 678 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 679 | struct address_space *mapping = out->f_mapping; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 680 | ssize_t ret; |
| 681 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 682 | ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 683 | |
| 684 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 685 | * If file or inode is SYNC and we actually wrote some data, sync it. |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 686 | */ |
| 687 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(mapping->host)) |
| 688 | && ret > 0) { |
| 689 | struct inode *inode = mapping->host; |
| 690 | int err; |
| 691 | |
| 692 | mutex_lock(&inode->i_mutex); |
| 693 | err = generic_osync_inode(mapping->host, mapping, |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 694 | OSYNC_METADATA|OSYNC_DATA); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 695 | mutex_unlock(&inode->i_mutex); |
| 696 | |
| 697 | if (err) |
| 698 | ret = err; |
| 699 | } |
| 700 | |
| 701 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 702 | } |
| 703 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 704 | EXPORT_SYMBOL(generic_file_splice_write); |
| 705 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 706 | /** |
| 707 | * generic_splice_sendpage - splice data from a pipe to a socket |
| 708 | * @inode: pipe inode |
| 709 | * @out: socket to write to |
| 710 | * @len: number of bytes to splice |
| 711 | * @flags: splice modifier flags |
| 712 | * |
| 713 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 714 | * is involved. |
| 715 | * |
| 716 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 717 | 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^] | 718 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 719 | { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 720 | return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 721 | } |
| 722 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 723 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 724 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 725 | /* |
| 726 | * Attempt to initiate a splice from pipe to file. |
| 727 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 728 | 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^] | 729 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 730 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 731 | int ret; |
| 732 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 733 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 734 | return -EINVAL; |
| 735 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 736 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 737 | return -EBADF; |
| 738 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 739 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 740 | if (unlikely(ret < 0)) |
| 741 | return ret; |
| 742 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 743 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 744 | } |
| 745 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 746 | /* |
| 747 | * Attempt to initiate a splice from a file to a pipe. |
| 748 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 749 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 750 | struct pipe_inode_info *pipe, size_t len, |
| 751 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 752 | { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 753 | loff_t isize, left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 754 | int ret; |
| 755 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 756 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 757 | return -EINVAL; |
| 758 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 759 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 760 | return -EBADF; |
| 761 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 762 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 763 | if (unlikely(ret < 0)) |
| 764 | return ret; |
| 765 | |
| 766 | isize = i_size_read(in->f_mapping->host); |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 767 | if (unlikely(*ppos >= isize)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 768 | return 0; |
| 769 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 770 | left = isize - *ppos; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 771 | if (unlikely(left < len)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 772 | len = left; |
| 773 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 774 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 775 | } |
| 776 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 777 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 778 | size_t len, unsigned int flags) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 779 | { |
| 780 | struct pipe_inode_info *pipe; |
| 781 | long ret, bytes; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 782 | loff_t out_off; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 783 | umode_t i_mode; |
| 784 | int i; |
| 785 | |
| 786 | /* |
| 787 | * We require the input being a regular file, as we don't want to |
| 788 | * randomly drop data for eg socket -> socket splicing. Use the |
| 789 | * piped splicing for that! |
| 790 | */ |
| 791 | i_mode = in->f_dentry->d_inode->i_mode; |
| 792 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 793 | return -EINVAL; |
| 794 | |
| 795 | /* |
| 796 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 797 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 798 | */ |
| 799 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 800 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 801 | pipe = alloc_pipe_info(NULL); |
| 802 | if (!pipe) |
| 803 | return -ENOMEM; |
| 804 | |
| 805 | /* |
| 806 | * We don't have an immediate reader, but we'll read the stuff |
| 807 | * out of the pipe right after the move_to_pipe(). So set |
| 808 | * PIPE_READERS appropriately. |
| 809 | */ |
| 810 | pipe->readers = 1; |
| 811 | |
| 812 | current->splice_pipe = pipe; |
| 813 | } |
| 814 | |
| 815 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 816 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 817 | */ |
| 818 | ret = 0; |
| 819 | bytes = 0; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 820 | out_off = 0; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 821 | |
| 822 | while (len) { |
| 823 | size_t read_len, max_read_len; |
| 824 | |
| 825 | /* |
| 826 | * Do at most PIPE_BUFFERS pages worth of transfer: |
| 827 | */ |
| 828 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); |
| 829 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 830 | ret = do_splice_to(in, ppos, pipe, max_read_len, flags); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 831 | if (unlikely(ret < 0)) |
| 832 | goto out_release; |
| 833 | |
| 834 | read_len = ret; |
| 835 | |
| 836 | /* |
| 837 | * NOTE: nonblocking mode only applies to the input. We |
| 838 | * must not do the output in nonblocking mode as then we |
| 839 | * could get stuck data in the internal pipe: |
| 840 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 841 | ret = do_splice_from(pipe, out, &out_off, read_len, |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 842 | flags & ~SPLICE_F_NONBLOCK); |
| 843 | if (unlikely(ret < 0)) |
| 844 | goto out_release; |
| 845 | |
| 846 | bytes += ret; |
| 847 | len -= ret; |
| 848 | |
| 849 | /* |
| 850 | * In nonblocking mode, if we got back a short read then |
| 851 | * that was due to either an IO error or due to the |
| 852 | * pagecache entry not being there. In the IO error case |
| 853 | * the _next_ splice attempt will produce a clean IO error |
| 854 | * return value (not a short read), so in both cases it's |
| 855 | * correct to break out of the loop here: |
| 856 | */ |
| 857 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) |
| 858 | break; |
| 859 | } |
| 860 | |
| 861 | pipe->nrbufs = pipe->curbuf = 0; |
| 862 | |
| 863 | return bytes; |
| 864 | |
| 865 | out_release: |
| 866 | /* |
| 867 | * If we did an incomplete transfer we must release |
| 868 | * the pipe buffers in question: |
| 869 | */ |
| 870 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 871 | struct pipe_buffer *buf = pipe->bufs + i; |
| 872 | |
| 873 | if (buf->ops) { |
| 874 | buf->ops->release(pipe, buf); |
| 875 | buf->ops = NULL; |
| 876 | } |
| 877 | } |
| 878 | pipe->nrbufs = pipe->curbuf = 0; |
| 879 | |
| 880 | /* |
| 881 | * If we transferred some data, return the number of bytes: |
| 882 | */ |
| 883 | if (bytes > 0) |
| 884 | return bytes; |
| 885 | |
| 886 | return ret; |
| 887 | } |
| 888 | |
| 889 | EXPORT_SYMBOL(do_splice_direct); |
| 890 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 891 | /* |
| 892 | * Determine where to splice to/from. |
| 893 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 894 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 895 | struct file *out, loff_t __user *off_out, |
| 896 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 897 | { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 898 | struct pipe_inode_info *pipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 899 | loff_t offset, *off; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 900 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 901 | pipe = in->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 902 | if (pipe) { |
| 903 | if (off_in) |
| 904 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 905 | if (off_out) { |
| 906 | if (out->f_op->llseek == no_llseek) |
| 907 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 908 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 909 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 910 | off = &offset; |
| 911 | } else |
| 912 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 913 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 914 | return do_splice_from(pipe, out, off, len, flags); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 915 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 916 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 917 | pipe = out->f_dentry->d_inode->i_pipe; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 918 | if (pipe) { |
| 919 | if (off_out) |
| 920 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 921 | if (off_in) { |
| 922 | if (in->f_op->llseek == no_llseek) |
| 923 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 924 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 925 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 926 | off = &offset; |
| 927 | } else |
| 928 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 929 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame^] | 930 | return do_splice_to(in, off, pipe, len, flags); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 931 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 932 | |
| 933 | return -EINVAL; |
| 934 | } |
| 935 | |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 936 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
| 937 | int fd_out, loff_t __user *off_out, |
| 938 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 939 | { |
| 940 | long error; |
| 941 | struct file *in, *out; |
| 942 | int fput_in, fput_out; |
| 943 | |
| 944 | if (unlikely(!len)) |
| 945 | return 0; |
| 946 | |
| 947 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 948 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 949 | if (in) { |
| 950 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 951 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 952 | if (out) { |
| 953 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 954 | error = do_splice(in, off_in, |
| 955 | out, off_out, |
| 956 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 957 | fput_light(out, fput_out); |
| 958 | } |
| 959 | } |
| 960 | |
| 961 | fput_light(in, fput_in); |
| 962 | } |
| 963 | |
| 964 | return error; |
| 965 | } |