Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1 | /* |
| 2 | * "splice": joining two ropes together by interweaving their strands. |
| 3 | * |
| 4 | * This is the "extended pipe" functionality, where a pipe is used as |
| 5 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel |
| 6 | * buffer that you can use to transfer data from one end to the other. |
| 7 | * |
| 8 | * The traditional unix read/write is extended with a "splice()" operation |
| 9 | * that transfers data buffers to or from a pipe buffer. |
| 10 | * |
| 11 | * Named by Larry McVoy, original implementation from Linus, extended by |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 12 | * Jens to support splicing to files, network, direct splicing, etc and |
| 13 | * fixing lots of bugs. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 14 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 16 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
| 17 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 18 | * |
| 19 | */ |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/file.h> |
| 22 | #include <linux/pagemap.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 23 | #include <linux/splice.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 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> |
James Morris | 29ce205 | 2007-07-13 11:44:32 +0200 | [diff] [blame] | 31 | #include <linux/security.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 32 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 33 | /* |
| 34 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 35 | * a vm helper function, it's already simplified quite a bit by the |
| 36 | * addition of remove_mapping(). If success is returned, the caller may |
| 37 | * attempt to reuse this page for another destination. |
| 38 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 39 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 40 | struct pipe_buffer *buf) |
| 41 | { |
| 42 | struct page *page = buf->page; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 43 | struct address_space *mapping; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 44 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 45 | lock_page(page); |
| 46 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 47 | mapping = page_mapping(page); |
| 48 | if (mapping) { |
| 49 | WARN_ON(!PageUptodate(page)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 50 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 51 | /* |
| 52 | * At least for ext2 with nobh option, we need to wait on |
| 53 | * writeback completing on this page, since we'll remove it |
| 54 | * from the pagecache. Otherwise truncate wont wait on the |
| 55 | * page, allowing the disk blocks to be reused by someone else |
| 56 | * before we actually wrote our data to them. fs corruption |
| 57 | * ensues. |
| 58 | */ |
| 59 | wait_on_page_writeback(page); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 60 | |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame^] | 61 | if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) |
| 62 | goto out_unlock; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 63 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 64 | /* |
| 65 | * If we succeeded in removing the mapping, set LRU flag |
| 66 | * and return good. |
| 67 | */ |
| 68 | if (remove_mapping(mapping, page)) { |
| 69 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 70 | return 0; |
| 71 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 72 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 73 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 74 | /* |
| 75 | * Raced with truncate or failed to remove page from current |
| 76 | * address space, unlock and return failure. |
| 77 | */ |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame^] | 78 | out_unlock: |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 79 | unlock_page(page); |
| 80 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 81 | } |
| 82 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 83 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 84 | struct pipe_buffer *buf) |
| 85 | { |
| 86 | page_cache_release(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 87 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 88 | } |
| 89 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 90 | /* |
| 91 | * Check whether the contents of buf is OK to access. Since the content |
| 92 | * is a page cache page, IO may be in flight. |
| 93 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 94 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 95 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 96 | { |
| 97 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 98 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 99 | |
| 100 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 101 | lock_page(page); |
| 102 | |
| 103 | /* |
| 104 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 105 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 106 | */ |
| 107 | if (!page->mapping) { |
| 108 | err = -ENODATA; |
| 109 | goto error; |
| 110 | } |
| 111 | |
| 112 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 113 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 114 | */ |
| 115 | if (!PageUptodate(page)) { |
| 116 | err = -EIO; |
| 117 | goto error; |
| 118 | } |
| 119 | |
| 120 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 121 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 122 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 123 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 124 | } |
| 125 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 126 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 127 | error: |
| 128 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 129 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 130 | } |
| 131 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 132 | static const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 133 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 134 | .map = generic_pipe_buf_map, |
| 135 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 136 | .confirm = page_cache_pipe_buf_confirm, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 137 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 138 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 139 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 140 | }; |
| 141 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 142 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 143 | struct pipe_buffer *buf) |
| 144 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 145 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 146 | return 1; |
| 147 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 148 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 149 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 150 | } |
| 151 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 152 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 153 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 154 | .map = generic_pipe_buf_map, |
| 155 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 156 | .confirm = generic_pipe_buf_confirm, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 157 | .release = page_cache_pipe_buf_release, |
| 158 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 159 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 160 | }; |
| 161 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 162 | /** |
| 163 | * splice_to_pipe - fill passed data into a pipe |
| 164 | * @pipe: pipe to fill |
| 165 | * @spd: data to fill |
| 166 | * |
| 167 | * Description: |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 168 | * @spd contains a map of pages and len/offset tuples, along with |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 169 | * the struct pipe_buf_operations associated with these pages. This |
| 170 | * function will link that data to the pipe. |
| 171 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 172 | */ |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 173 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 174 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 175 | { |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 176 | unsigned int spd_pages = spd->nr_pages; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 177 | int ret, do_wakeup, page_nr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 178 | |
| 179 | ret = 0; |
| 180 | do_wakeup = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 181 | page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 182 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 183 | if (pipe->inode) |
| 184 | mutex_lock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 185 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 186 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 187 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 188 | send_sig(SIGPIPE, current, 0); |
| 189 | if (!ret) |
| 190 | ret = -EPIPE; |
| 191 | break; |
| 192 | } |
| 193 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 194 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 195 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 196 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 197 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 198 | buf->page = spd->pages[page_nr]; |
| 199 | buf->offset = spd->partial[page_nr].offset; |
| 200 | buf->len = spd->partial[page_nr].len; |
Jens Axboe | 497f962 | 2007-06-11 12:00:45 +0200 | [diff] [blame] | 201 | buf->private = spd->partial[page_nr].private; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 202 | buf->ops = spd->ops; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 203 | if (spd->flags & SPLICE_F_GIFT) |
| 204 | buf->flags |= PIPE_BUF_FLAG_GIFT; |
| 205 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 206 | pipe->nrbufs++; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 207 | page_nr++; |
| 208 | ret += buf->len; |
| 209 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 210 | if (pipe->inode) |
| 211 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 212 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 213 | if (!--spd->nr_pages) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 214 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 215 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 216 | continue; |
| 217 | |
| 218 | break; |
| 219 | } |
| 220 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 221 | if (spd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 222 | if (!ret) |
| 223 | ret = -EAGAIN; |
| 224 | break; |
| 225 | } |
| 226 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 227 | if (signal_pending(current)) { |
| 228 | if (!ret) |
| 229 | ret = -ERESTARTSYS; |
| 230 | break; |
| 231 | } |
| 232 | |
| 233 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 234 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 235 | if (waitqueue_active(&pipe->wait)) |
| 236 | wake_up_interruptible_sync(&pipe->wait); |
| 237 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 238 | do_wakeup = 0; |
| 239 | } |
| 240 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 241 | pipe->waiting_writers++; |
| 242 | pipe_wait(pipe); |
| 243 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 244 | } |
| 245 | |
Jens Axboe | 02676e5 | 2007-06-15 13:16:13 +0200 | [diff] [blame] | 246 | if (pipe->inode) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 247 | mutex_unlock(&pipe->inode->i_mutex); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 248 | |
Jens Axboe | 02676e5 | 2007-06-15 13:16:13 +0200 | [diff] [blame] | 249 | if (do_wakeup) { |
| 250 | smp_mb(); |
| 251 | if (waitqueue_active(&pipe->wait)) |
| 252 | wake_up_interruptible(&pipe->wait); |
| 253 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 254 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 255 | } |
| 256 | |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 257 | while (page_nr < spd_pages) |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 258 | spd->spd_release(spd, page_nr++); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 259 | |
| 260 | return ret; |
| 261 | } |
| 262 | |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 263 | static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) |
| 264 | { |
| 265 | page_cache_release(spd->pages[i]); |
| 266 | } |
| 267 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 268 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 269 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 270 | struct pipe_inode_info *pipe, size_t len, |
| 271 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 272 | { |
| 273 | struct address_space *mapping = in->f_mapping; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 274 | unsigned int loff, nr_pages, req_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 275 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 276 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 277 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 278 | pgoff_t index, end_index; |
| 279 | loff_t isize; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 280 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 281 | struct splice_pipe_desc spd = { |
| 282 | .pages = pages, |
| 283 | .partial = partial, |
| 284 | .flags = flags, |
| 285 | .ops = &page_cache_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 286 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 287 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 288 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 289 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 290 | loff = *ppos & ~PAGE_CACHE_MASK; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 291 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 292 | nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 293 | |
| 294 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 295 | * Lookup the (hopefully) full range of pages we need. |
| 296 | */ |
| 297 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 298 | index += spd.nr_pages; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 299 | |
| 300 | /* |
| 301 | * If find_get_pages_contig() returned fewer pages than we needed, |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 302 | * readahead/allocate the rest and fill in the holes. |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 303 | */ |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 304 | if (spd.nr_pages < nr_pages) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 305 | page_cache_sync_readahead(mapping, &in->f_ra, in, |
| 306 | index, req_pages - spd.nr_pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 307 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 308 | error = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 309 | while (spd.nr_pages < nr_pages) { |
| 310 | /* |
| 311 | * Page could be there, find_get_pages_contig() breaks on |
| 312 | * the first hole. |
| 313 | */ |
| 314 | page = find_get_page(mapping, index); |
| 315 | if (!page) { |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 316 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 317 | * page didn't exist, allocate one. |
| 318 | */ |
| 319 | page = page_cache_alloc_cold(mapping); |
| 320 | if (!page) |
| 321 | break; |
| 322 | |
| 323 | error = add_to_page_cache_lru(page, mapping, index, |
Hugh Dickins | 4cd1350 | 2008-04-03 23:35:22 +0100 | [diff] [blame] | 324 | mapping_gfp_mask(mapping)); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 325 | if (unlikely(error)) { |
| 326 | page_cache_release(page); |
Jens Axboe | a054887 | 2006-05-03 10:58:22 +0200 | [diff] [blame] | 327 | if (error == -EEXIST) |
| 328 | continue; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 329 | break; |
| 330 | } |
| 331 | /* |
| 332 | * add_to_page_cache() locks the page, unlock it |
| 333 | * to avoid convoluting the logic below even more. |
| 334 | */ |
| 335 | unlock_page(page); |
| 336 | } |
| 337 | |
| 338 | pages[spd.nr_pages++] = page; |
| 339 | index++; |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Now loop over the map and see if we need to start IO on any |
| 344 | * pages, fill in the partial map, etc. |
| 345 | */ |
| 346 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 347 | nr_pages = spd.nr_pages; |
| 348 | spd.nr_pages = 0; |
| 349 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 350 | unsigned int this_len; |
| 351 | |
| 352 | if (!len) |
| 353 | break; |
| 354 | |
| 355 | /* |
| 356 | * this_len is the max we'll use from this page |
| 357 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 358 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 359 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 360 | |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 361 | if (PageReadahead(page)) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 362 | page_cache_async_readahead(mapping, &in->f_ra, in, |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 363 | page, index, req_pages - page_nr); |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 364 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 365 | /* |
| 366 | * If the page isn't uptodate, we may need to start io on it |
| 367 | */ |
| 368 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 369 | /* |
| 370 | * If in nonblock mode then dont block on waiting |
| 371 | * for an in-flight io page |
| 372 | */ |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 373 | if (flags & SPLICE_F_NONBLOCK) { |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 374 | if (TestSetPageLocked(page)) { |
| 375 | error = -EAGAIN; |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 376 | break; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 377 | } |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 378 | } else |
| 379 | lock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 380 | |
| 381 | /* |
| 382 | * page was truncated, stop here. if this isn't the |
| 383 | * first page, we'll just complete what we already |
| 384 | * added |
| 385 | */ |
| 386 | if (!page->mapping) { |
| 387 | unlock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 388 | break; |
| 389 | } |
| 390 | /* |
| 391 | * page was already under io and is now done, great |
| 392 | */ |
| 393 | if (PageUptodate(page)) { |
| 394 | unlock_page(page); |
| 395 | goto fill_it; |
| 396 | } |
| 397 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 398 | /* |
| 399 | * need to read in the page |
| 400 | */ |
| 401 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 402 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 403 | /* |
| 404 | * We really should re-lookup the page here, |
| 405 | * but it complicates things a lot. Instead |
| 406 | * lets just do what we already stored, and |
| 407 | * we'll get it the next time we are called. |
| 408 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 409 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 410 | error = 0; |
| 411 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 412 | break; |
| 413 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 414 | } |
| 415 | fill_it: |
| 416 | /* |
| 417 | * i_size must be checked after PageUptodate. |
| 418 | */ |
| 419 | isize = i_size_read(mapping->host); |
| 420 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 421 | if (unlikely(!isize || index > end_index)) |
| 422 | break; |
| 423 | |
| 424 | /* |
| 425 | * if this is the last page, see if we need to shrink |
| 426 | * the length and stop |
| 427 | */ |
| 428 | if (end_index == index) { |
| 429 | unsigned int plen; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 430 | |
| 431 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 432 | * max good bytes in this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 433 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 434 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 435 | if (plen <= loff) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 436 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 437 | |
| 438 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 439 | * force quit after adding this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 440 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 441 | this_len = min(this_len, plen - loff); |
| 442 | len = this_len; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 443 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 444 | |
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 | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 448 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 449 | spd.nr_pages++; |
| 450 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 451 | } |
| 452 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 453 | /* |
Hugh Dickins | 475ecad | 2007-06-07 09:36:00 +0200 | [diff] [blame] | 454 | * Release any pages at the end, if we quit early. 'page_nr' is how far |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 455 | * we got, 'nr_pages' is how many pages are in the map. |
| 456 | */ |
| 457 | while (page_nr < nr_pages) |
| 458 | page_cache_release(pages[page_nr++]); |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 459 | in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 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 |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 470 | * @ppos: position in @in |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 471 | * @pipe: pipe to splice to |
| 472 | * @len: number of bytes to splice |
| 473 | * @flags: splice modifier flags |
| 474 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 475 | * Description: |
| 476 | * Will read pages from given file and fill them into a pipe. Can be |
| 477 | * used as long as the address_space operations for the source implements |
| 478 | * a readpage() hook. |
| 479 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 480 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 481 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 482 | struct pipe_inode_info *pipe, size_t len, |
| 483 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 484 | { |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 485 | loff_t isize, left; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 486 | int ret; |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 487 | |
| 488 | isize = i_size_read(in->f_mapping->host); |
| 489 | if (unlikely(*ppos >= isize)) |
| 490 | return 0; |
| 491 | |
| 492 | left = isize - *ppos; |
| 493 | if (unlikely(left < len)) |
| 494 | len = left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 495 | |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 496 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
| 497 | if (ret > 0) |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 498 | *ppos += ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 499 | |
| 500 | return ret; |
| 501 | } |
| 502 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 503 | EXPORT_SYMBOL(generic_file_splice_read); |
| 504 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 505 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 506 | * 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] | 507 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 508 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 509 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 510 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 511 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 512 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 513 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 514 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 515 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 516 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 517 | if (!ret) { |
| 518 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 519 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 520 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 521 | sd->len, &pos, more); |
| 522 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 523 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 524 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 525 | } |
| 526 | |
| 527 | /* |
| 528 | * This is a little more tricky than the file -> pipe splicing. There are |
| 529 | * basically three cases: |
| 530 | * |
| 531 | * - Destination page already exists in the address space and there |
| 532 | * are users of it. For that case we have no other option that |
| 533 | * copying the data. Tough luck. |
| 534 | * - Destination page already exists in the address space, but there |
| 535 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 536 | * through to last case. |
| 537 | * - Destination page does not exist, we can add the pipe page to |
| 538 | * the page cache and avoid the copy. |
| 539 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 540 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 541 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 542 | * file address space page cache. This is possible if no one else has |
| 543 | * the pipe page referenced outside of the pipe and page cache. If |
| 544 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 545 | * 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] | 546 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 547 | 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] | 548 | struct splice_desc *sd) |
| 549 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 550 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 551 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 552 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 553 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 554 | void *fsdata; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 555 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 556 | |
| 557 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 558 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 559 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 560 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 561 | if (unlikely(ret)) |
| 562 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 563 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 564 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 565 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 566 | this_len = sd->len; |
| 567 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 568 | this_len = PAGE_CACHE_SIZE - offset; |
| 569 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 570 | ret = pagecache_write_begin(file, mapping, sd->pos, this_len, |
| 571 | AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); |
| 572 | if (unlikely(ret)) |
| 573 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 574 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 575 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 576 | /* |
| 577 | * Careful, ->map() uses KM_USER0! |
| 578 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 579 | char *src = buf->ops->map(pipe, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 580 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 581 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 582 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 583 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 584 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 585 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 586 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 587 | ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, |
| 588 | page, fsdata); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 589 | out: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 590 | return ret; |
| 591 | } |
| 592 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 593 | /** |
| 594 | * __splice_from_pipe - splice data from a pipe to given actor |
| 595 | * @pipe: pipe to splice from |
| 596 | * @sd: information to @actor |
| 597 | * @actor: handler that splices the data |
| 598 | * |
| 599 | * Description: |
| 600 | * This function does little more than loop over the pipe and call |
| 601 | * @actor to do the actual moving of a single struct pipe_buffer to |
| 602 | * the desired destination. See pipe_to_file, pipe_to_sendpage, or |
| 603 | * pipe_to_user. |
| 604 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 605 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 606 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 607 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 608 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 609 | int ret, do_wakeup, err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 610 | |
| 611 | ret = 0; |
| 612 | do_wakeup = 0; |
| 613 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 614 | for (;;) { |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 615 | if (pipe->nrbufs) { |
| 616 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 617 | const struct pipe_buf_operations *ops = buf->ops; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 618 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 619 | sd->len = buf->len; |
| 620 | if (sd->len > sd->total_len) |
| 621 | sd->len = sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 622 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 623 | err = actor(pipe, buf, sd); |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 624 | if (err <= 0) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 625 | if (!ret && err != -ENODATA) |
| 626 | ret = err; |
| 627 | |
| 628 | break; |
| 629 | } |
| 630 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 631 | ret += err; |
| 632 | buf->offset += err; |
| 633 | buf->len -= err; |
| 634 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 635 | sd->len -= err; |
| 636 | sd->pos += err; |
| 637 | sd->total_len -= err; |
| 638 | if (sd->len) |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 639 | continue; |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 640 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 641 | if (!buf->len) { |
| 642 | buf->ops = NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 643 | ops->release(pipe, buf); |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 644 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 645 | pipe->nrbufs--; |
| 646 | if (pipe->inode) |
| 647 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 648 | } |
| 649 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 650 | if (!sd->total_len) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 651 | break; |
| 652 | } |
| 653 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 654 | if (pipe->nrbufs) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 655 | continue; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 656 | if (!pipe->writers) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 657 | break; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 658 | if (!pipe->waiting_writers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 659 | if (ret) |
| 660 | break; |
| 661 | } |
| 662 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 663 | if (sd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 664 | if (!ret) |
| 665 | ret = -EAGAIN; |
| 666 | break; |
| 667 | } |
| 668 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 669 | if (signal_pending(current)) { |
| 670 | if (!ret) |
| 671 | ret = -ERESTARTSYS; |
| 672 | break; |
| 673 | } |
| 674 | |
| 675 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 676 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 677 | if (waitqueue_active(&pipe->wait)) |
| 678 | wake_up_interruptible_sync(&pipe->wait); |
| 679 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 680 | do_wakeup = 0; |
| 681 | } |
| 682 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 683 | pipe_wait(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 684 | } |
| 685 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 686 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 687 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 688 | if (waitqueue_active(&pipe->wait)) |
| 689 | wake_up_interruptible(&pipe->wait); |
| 690 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 691 | } |
| 692 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 693 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 694 | } |
Mark Fasheh | 40bee44 | 2007-03-21 13:11:02 +0100 | [diff] [blame] | 695 | EXPORT_SYMBOL(__splice_from_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 696 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 697 | /** |
| 698 | * splice_from_pipe - splice data from a pipe to a file |
| 699 | * @pipe: pipe to splice from |
| 700 | * @out: file to splice to |
| 701 | * @ppos: position in @out |
| 702 | * @len: how many bytes to splice |
| 703 | * @flags: splice modifier flags |
| 704 | * @actor: handler that splices the data |
| 705 | * |
| 706 | * Description: |
| 707 | * See __splice_from_pipe. This function locks the input and output inodes, |
| 708 | * otherwise it's identical to __splice_from_pipe(). |
| 709 | * |
| 710 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 711 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 712 | loff_t *ppos, size_t len, unsigned int flags, |
| 713 | splice_actor *actor) |
| 714 | { |
| 715 | ssize_t ret; |
| 716 | struct inode *inode = out->f_mapping->host; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 717 | struct splice_desc sd = { |
| 718 | .total_len = len, |
| 719 | .flags = flags, |
| 720 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 721 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 722 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 723 | |
| 724 | /* |
| 725 | * The actor worker might be calling ->prepare_write and |
| 726 | * ->commit_write. Most of the time, these expect i_mutex to |
| 727 | * be held. Since this may result in an ABBA deadlock with |
| 728 | * pipe->inode, we have to order lock acquiry here. |
| 729 | */ |
| 730 | inode_double_lock(inode, pipe->inode); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 731 | ret = __splice_from_pipe(pipe, &sd, actor); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 732 | inode_double_unlock(inode, pipe->inode); |
| 733 | |
| 734 | return ret; |
| 735 | } |
| 736 | |
| 737 | /** |
| 738 | * generic_file_splice_write_nolock - generic_file_splice_write without mutexes |
| 739 | * @pipe: pipe info |
| 740 | * @out: file to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 741 | * @ppos: position in @out |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 742 | * @len: number of bytes to splice |
| 743 | * @flags: splice modifier flags |
| 744 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 745 | * Description: |
| 746 | * Will either move or copy pages (determined by @flags options) from |
| 747 | * the given pipe inode to the given file. The caller is responsible |
| 748 | * for acquiring i_mutex on both inodes. |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 749 | * |
| 750 | */ |
| 751 | ssize_t |
| 752 | generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, |
| 753 | loff_t *ppos, size_t len, unsigned int flags) |
| 754 | { |
| 755 | struct address_space *mapping = out->f_mapping; |
| 756 | struct inode *inode = mapping->host; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 757 | struct splice_desc sd = { |
| 758 | .total_len = len, |
| 759 | .flags = flags, |
| 760 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 761 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 762 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 763 | ssize_t ret; |
| 764 | int err; |
| 765 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 766 | err = remove_suid(out->f_path.dentry); |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 767 | if (unlikely(err)) |
| 768 | return err; |
| 769 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 770 | ret = __splice_from_pipe(pipe, &sd, pipe_to_file); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 771 | if (ret > 0) { |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 772 | unsigned long nr_pages; |
| 773 | |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 774 | *ppos += ret; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 775 | nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 776 | |
| 777 | /* |
| 778 | * If file or inode is SYNC and we actually wrote some data, |
| 779 | * sync it. |
| 780 | */ |
| 781 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 782 | err = generic_osync_inode(inode, mapping, |
| 783 | OSYNC_METADATA|OSYNC_DATA); |
| 784 | |
| 785 | if (err) |
| 786 | ret = err; |
| 787 | } |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 788 | balance_dirty_pages_ratelimited_nr(mapping, nr_pages); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 789 | } |
| 790 | |
| 791 | return ret; |
| 792 | } |
| 793 | |
| 794 | EXPORT_SYMBOL(generic_file_splice_write_nolock); |
| 795 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 796 | /** |
| 797 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 798 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 799 | * @out: file to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 800 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 801 | * @len: number of bytes to splice |
| 802 | * @flags: splice modifier flags |
| 803 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 804 | * Description: |
| 805 | * Will either move or copy pages (determined by @flags options) from |
| 806 | * the given pipe inode to the given file. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 807 | * |
| 808 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 809 | ssize_t |
| 810 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 811 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 812 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 813 | struct address_space *mapping = out->f_mapping; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 814 | struct inode *inode = mapping->host; |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 815 | struct splice_desc sd = { |
| 816 | .total_len = len, |
| 817 | .flags = flags, |
| 818 | .pos = *ppos, |
| 819 | .u.file = out, |
| 820 | }; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 821 | ssize_t ret; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 822 | |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 823 | inode_double_lock(inode, pipe->inode); |
| 824 | ret = remove_suid(out->f_path.dentry); |
| 825 | if (likely(!ret)) |
| 826 | ret = __splice_from_pipe(pipe, &sd, pipe_to_file); |
| 827 | inode_double_unlock(inode, pipe->inode); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 828 | if (ret > 0) { |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 829 | unsigned long nr_pages; |
| 830 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 831 | *ppos += ret; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 832 | nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 833 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 834 | /* |
| 835 | * If file or inode is SYNC and we actually wrote some data, |
| 836 | * sync it. |
| 837 | */ |
| 838 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 839 | int err; |
| 840 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 841 | mutex_lock(&inode->i_mutex); |
| 842 | err = generic_osync_inode(inode, mapping, |
| 843 | OSYNC_METADATA|OSYNC_DATA); |
| 844 | mutex_unlock(&inode->i_mutex); |
| 845 | |
| 846 | if (err) |
| 847 | ret = err; |
| 848 | } |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 849 | balance_dirty_pages_ratelimited_nr(mapping, nr_pages); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 850 | } |
| 851 | |
| 852 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 853 | } |
| 854 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 855 | EXPORT_SYMBOL(generic_file_splice_write); |
| 856 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 857 | /** |
| 858 | * generic_splice_sendpage - splice data from a pipe to a socket |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 859 | * @pipe: pipe to splice from |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 860 | * @out: socket to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 861 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 862 | * @len: number of bytes to splice |
| 863 | * @flags: splice modifier flags |
| 864 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 865 | * Description: |
| 866 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 867 | * is involved. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 868 | * |
| 869 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 870 | 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] | 871 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 872 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 873 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 874 | } |
| 875 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 876 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 877 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 878 | /* |
| 879 | * Attempt to initiate a splice from pipe to file. |
| 880 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 881 | 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] | 882 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 883 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 884 | int ret; |
| 885 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 886 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 887 | return -EINVAL; |
| 888 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 889 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 890 | return -EBADF; |
| 891 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 892 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 893 | if (unlikely(ret < 0)) |
| 894 | return ret; |
| 895 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 896 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 897 | } |
| 898 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 899 | /* |
| 900 | * Attempt to initiate a splice from a file to a pipe. |
| 901 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 902 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 903 | struct pipe_inode_info *pipe, size_t len, |
| 904 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 905 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 906 | int ret; |
| 907 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 908 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 909 | return -EINVAL; |
| 910 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 911 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 912 | return -EBADF; |
| 913 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 914 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 915 | if (unlikely(ret < 0)) |
| 916 | return ret; |
| 917 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 918 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 919 | } |
| 920 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 921 | /** |
| 922 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 923 | * @in: file to splice from |
| 924 | * @sd: actor information on where to splice to |
| 925 | * @actor: handles the data splicing |
| 926 | * |
| 927 | * Description: |
| 928 | * This is a special case helper to splice directly between two |
| 929 | * points, without requiring an explicit pipe. Internally an allocated |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 930 | * pipe is cached in the process, and reused during the lifetime of |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 931 | * that process. |
| 932 | * |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 933 | */ |
| 934 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 935 | splice_direct_actor *actor) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 936 | { |
| 937 | struct pipe_inode_info *pipe; |
| 938 | long ret, bytes; |
| 939 | umode_t i_mode; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 940 | size_t len; |
| 941 | int i, flags; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 942 | |
| 943 | /* |
| 944 | * We require the input being a regular file, as we don't want to |
| 945 | * randomly drop data for eg socket -> socket splicing. Use the |
| 946 | * piped splicing for that! |
| 947 | */ |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 948 | i_mode = in->f_path.dentry->d_inode->i_mode; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 949 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 950 | return -EINVAL; |
| 951 | |
| 952 | /* |
| 953 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 954 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 955 | */ |
| 956 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 957 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 958 | pipe = alloc_pipe_info(NULL); |
| 959 | if (!pipe) |
| 960 | return -ENOMEM; |
| 961 | |
| 962 | /* |
| 963 | * 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] | 964 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 965 | * PIPE_READERS appropriately. |
| 966 | */ |
| 967 | pipe->readers = 1; |
| 968 | |
| 969 | current->splice_pipe = pipe; |
| 970 | } |
| 971 | |
| 972 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 973 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 974 | */ |
| 975 | ret = 0; |
| 976 | bytes = 0; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 977 | len = sd->total_len; |
| 978 | flags = sd->flags; |
| 979 | |
| 980 | /* |
| 981 | * Don't block on output, we have to drain the direct pipe. |
| 982 | */ |
| 983 | sd->flags &= ~SPLICE_F_NONBLOCK; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 984 | |
| 985 | while (len) { |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 986 | size_t read_len; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 987 | loff_t pos = sd->pos, prev_pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 988 | |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 989 | ret = do_splice_to(in, &pos, pipe, len, flags); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 990 | if (unlikely(ret <= 0)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 991 | goto out_release; |
| 992 | |
| 993 | read_len = ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 994 | sd->total_len = read_len; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 995 | |
| 996 | /* |
| 997 | * NOTE: nonblocking mode only applies to the input. We |
| 998 | * must not do the output in nonblocking mode as then we |
| 999 | * could get stuck data in the internal pipe: |
| 1000 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1001 | ret = actor(pipe, sd); |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1002 | if (unlikely(ret <= 0)) { |
| 1003 | sd->pos = prev_pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1004 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1005 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1006 | |
| 1007 | bytes += ret; |
| 1008 | len -= ret; |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1009 | sd->pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1010 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1011 | if (ret < read_len) { |
| 1012 | sd->pos = prev_pos + ret; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1013 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1014 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1015 | } |
| 1016 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1017 | done: |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1018 | pipe->nrbufs = pipe->curbuf = 0; |
Jens Axboe | 8084870 | 2008-01-30 12:24:48 +0100 | [diff] [blame] | 1019 | file_accessed(in); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1020 | return bytes; |
| 1021 | |
| 1022 | out_release: |
| 1023 | /* |
| 1024 | * If we did an incomplete transfer we must release |
| 1025 | * the pipe buffers in question: |
| 1026 | */ |
| 1027 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1028 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1029 | |
| 1030 | if (buf->ops) { |
| 1031 | buf->ops->release(pipe, buf); |
| 1032 | buf->ops = NULL; |
| 1033 | } |
| 1034 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1035 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1036 | if (!bytes) |
| 1037 | bytes = ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1038 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1039 | goto done; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1040 | } |
| 1041 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1042 | |
| 1043 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1044 | struct splice_desc *sd) |
| 1045 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1046 | struct file *file = sd->u.file; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1047 | |
| 1048 | return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); |
| 1049 | } |
| 1050 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1051 | /** |
| 1052 | * do_splice_direct - splices data directly between two files |
| 1053 | * @in: file to splice from |
| 1054 | * @ppos: input file offset |
| 1055 | * @out: file to splice to |
| 1056 | * @len: number of bytes to splice |
| 1057 | * @flags: splice modifier flags |
| 1058 | * |
| 1059 | * Description: |
| 1060 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1061 | * doing it in the application would incur an extra system call |
| 1062 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1063 | * can splice directly through a process-private pipe. |
| 1064 | * |
| 1065 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1066 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1067 | size_t len, unsigned int flags) |
| 1068 | { |
| 1069 | struct splice_desc sd = { |
| 1070 | .len = len, |
| 1071 | .total_len = len, |
| 1072 | .flags = flags, |
| 1073 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1074 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1075 | }; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1076 | long ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1077 | |
| 1078 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1079 | if (ret > 0) |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1080 | *ppos = sd.pos; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1081 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1082 | return ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1083 | } |
| 1084 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1085 | /* |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1086 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same |
| 1087 | * location, so checking ->i_pipe is not enough to verify that this is a |
| 1088 | * pipe. |
| 1089 | */ |
| 1090 | static inline struct pipe_inode_info *pipe_info(struct inode *inode) |
| 1091 | { |
| 1092 | if (S_ISFIFO(inode->i_mode)) |
| 1093 | return inode->i_pipe; |
| 1094 | |
| 1095 | return NULL; |
| 1096 | } |
| 1097 | |
| 1098 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1099 | * Determine where to splice to/from. |
| 1100 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1101 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1102 | struct file *out, loff_t __user *off_out, |
| 1103 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1104 | { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1105 | struct pipe_inode_info *pipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1106 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1107 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1108 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1109 | pipe = pipe_info(in->f_path.dentry->d_inode); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1110 | if (pipe) { |
| 1111 | if (off_in) |
| 1112 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1113 | if (off_out) { |
| 1114 | if (out->f_op->llseek == no_llseek) |
| 1115 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1116 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1117 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1118 | off = &offset; |
| 1119 | } else |
| 1120 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1121 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1122 | ret = do_splice_from(pipe, out, off, len, flags); |
| 1123 | |
| 1124 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1125 | ret = -EFAULT; |
| 1126 | |
| 1127 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1128 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1129 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1130 | pipe = pipe_info(out->f_path.dentry->d_inode); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1131 | if (pipe) { |
| 1132 | if (off_out) |
| 1133 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1134 | if (off_in) { |
| 1135 | if (in->f_op->llseek == no_llseek) |
| 1136 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1137 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1138 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1139 | off = &offset; |
| 1140 | } else |
| 1141 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1142 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1143 | ret = do_splice_to(in, off, pipe, len, flags); |
| 1144 | |
| 1145 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1146 | ret = -EFAULT; |
| 1147 | |
| 1148 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1149 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1150 | |
| 1151 | return -EINVAL; |
| 1152 | } |
| 1153 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1154 | /* |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1155 | * Do a copy-from-user while holding the mmap_semaphore for reading, in a |
| 1156 | * manner safe from deadlocking with simultaneous mmap() (grabbing mmap_sem |
| 1157 | * for writing) and page faulting on the user memory pointed to by src. |
| 1158 | * This assumes that we will very rarely hit the partial != 0 path, or this |
| 1159 | * will not be a win. |
| 1160 | */ |
| 1161 | static int copy_from_user_mmap_sem(void *dst, const void __user *src, size_t n) |
| 1162 | { |
| 1163 | int partial; |
| 1164 | |
Jens Axboe | 8811930 | 2008-02-08 08:49:14 -0800 | [diff] [blame] | 1165 | if (!access_ok(VERIFY_READ, src, n)) |
| 1166 | return -EFAULT; |
| 1167 | |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1168 | pagefault_disable(); |
| 1169 | partial = __copy_from_user_inatomic(dst, src, n); |
| 1170 | pagefault_enable(); |
| 1171 | |
| 1172 | /* |
| 1173 | * Didn't copy everything, drop the mmap_sem and do a faulting copy |
| 1174 | */ |
| 1175 | if (unlikely(partial)) { |
| 1176 | up_read(¤t->mm->mmap_sem); |
| 1177 | partial = copy_from_user(dst, src, n); |
| 1178 | down_read(¤t->mm->mmap_sem); |
| 1179 | } |
| 1180 | |
| 1181 | return partial; |
| 1182 | } |
| 1183 | |
| 1184 | /* |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1185 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1186 | * partial_page structure, we can map several non-contiguous ranges into |
| 1187 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1188 | * Could easily be exported as a generic helper for other users, in which |
| 1189 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1190 | */ |
| 1191 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1192 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1193 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1194 | { |
| 1195 | int buffers = 0, error = 0; |
| 1196 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1197 | down_read(¤t->mm->mmap_sem); |
| 1198 | |
| 1199 | while (nr_vecs) { |
| 1200 | unsigned long off, npages; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1201 | struct iovec entry; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1202 | void __user *base; |
| 1203 | size_t len; |
| 1204 | int i; |
| 1205 | |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1206 | error = -EFAULT; |
| 1207 | if (copy_from_user_mmap_sem(&entry, iov, sizeof(entry))) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1208 | break; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1209 | |
| 1210 | base = entry.iov_base; |
| 1211 | len = entry.iov_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1212 | |
| 1213 | /* |
| 1214 | * Sanity check this iovec. 0 read succeeds. |
| 1215 | */ |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1216 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1217 | if (unlikely(!len)) |
| 1218 | break; |
| 1219 | error = -EFAULT; |
Bastian Blank | 712a30e | 2008-02-10 16:47:57 +0200 | [diff] [blame] | 1220 | if (!access_ok(VERIFY_READ, base, len)) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1221 | break; |
| 1222 | |
| 1223 | /* |
| 1224 | * Get this base offset and number of pages, then map |
| 1225 | * in the user pages. |
| 1226 | */ |
| 1227 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1228 | |
| 1229 | /* |
| 1230 | * If asked for alignment, the offset must be zero and the |
| 1231 | * length a multiple of the PAGE_SIZE. |
| 1232 | */ |
| 1233 | error = -EINVAL; |
| 1234 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1235 | break; |
| 1236 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1237 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1238 | if (npages > PIPE_BUFFERS - buffers) |
| 1239 | npages = PIPE_BUFFERS - buffers; |
| 1240 | |
| 1241 | error = get_user_pages(current, current->mm, |
| 1242 | (unsigned long) base, npages, 0, 0, |
| 1243 | &pages[buffers], NULL); |
| 1244 | |
| 1245 | if (unlikely(error <= 0)) |
| 1246 | break; |
| 1247 | |
| 1248 | /* |
| 1249 | * Fill this contiguous range into the partial page map. |
| 1250 | */ |
| 1251 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1252 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1253 | |
| 1254 | partial[buffers].offset = off; |
| 1255 | partial[buffers].len = plen; |
| 1256 | |
| 1257 | off = 0; |
| 1258 | len -= plen; |
| 1259 | buffers++; |
| 1260 | } |
| 1261 | |
| 1262 | /* |
| 1263 | * We didn't complete this iov, stop here since it probably |
| 1264 | * means we have to move some of this into a pipe to |
| 1265 | * be able to continue. |
| 1266 | */ |
| 1267 | if (len) |
| 1268 | break; |
| 1269 | |
| 1270 | /* |
| 1271 | * Don't continue if we mapped fewer pages than we asked for, |
| 1272 | * or if we mapped the max number of pages that we have |
| 1273 | * room for. |
| 1274 | */ |
| 1275 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1276 | break; |
| 1277 | |
| 1278 | nr_vecs--; |
| 1279 | iov++; |
| 1280 | } |
| 1281 | |
| 1282 | up_read(¤t->mm->mmap_sem); |
| 1283 | |
| 1284 | if (buffers) |
| 1285 | return buffers; |
| 1286 | |
| 1287 | return error; |
| 1288 | } |
| 1289 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1290 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1291 | struct splice_desc *sd) |
| 1292 | { |
| 1293 | char *src; |
| 1294 | int ret; |
| 1295 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 1296 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1297 | if (unlikely(ret)) |
| 1298 | return ret; |
| 1299 | |
| 1300 | /* |
| 1301 | * See if we can use the atomic maps, by prefaulting in the |
| 1302 | * pages and doing an atomic copy |
| 1303 | */ |
| 1304 | if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { |
| 1305 | src = buf->ops->map(pipe, buf, 1); |
| 1306 | ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, |
| 1307 | sd->len); |
| 1308 | buf->ops->unmap(pipe, buf, src); |
| 1309 | if (!ret) { |
| 1310 | ret = sd->len; |
| 1311 | goto out; |
| 1312 | } |
| 1313 | } |
| 1314 | |
| 1315 | /* |
| 1316 | * No dice, use slow non-atomic map and copy |
| 1317 | */ |
| 1318 | src = buf->ops->map(pipe, buf, 0); |
| 1319 | |
| 1320 | ret = sd->len; |
| 1321 | if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) |
| 1322 | ret = -EFAULT; |
| 1323 | |
Jens Axboe | 6866bef | 2007-10-16 10:01:29 +0200 | [diff] [blame] | 1324 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1325 | out: |
| 1326 | if (ret > 0) |
| 1327 | sd->u.userptr += ret; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1328 | return ret; |
| 1329 | } |
| 1330 | |
| 1331 | /* |
| 1332 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1333 | * as a simple copy of the pipes pages to the user iov. |
| 1334 | */ |
| 1335 | static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, |
| 1336 | unsigned long nr_segs, unsigned int flags) |
| 1337 | { |
| 1338 | struct pipe_inode_info *pipe; |
| 1339 | struct splice_desc sd; |
| 1340 | ssize_t size; |
| 1341 | int error; |
| 1342 | long ret; |
| 1343 | |
| 1344 | pipe = pipe_info(file->f_path.dentry->d_inode); |
| 1345 | if (!pipe) |
| 1346 | return -EBADF; |
| 1347 | |
| 1348 | if (pipe->inode) |
| 1349 | mutex_lock(&pipe->inode->i_mutex); |
| 1350 | |
| 1351 | error = ret = 0; |
| 1352 | while (nr_segs) { |
| 1353 | void __user *base; |
| 1354 | size_t len; |
| 1355 | |
| 1356 | /* |
| 1357 | * Get user address base and length for this iovec. |
| 1358 | */ |
| 1359 | error = get_user(base, &iov->iov_base); |
| 1360 | if (unlikely(error)) |
| 1361 | break; |
| 1362 | error = get_user(len, &iov->iov_len); |
| 1363 | if (unlikely(error)) |
| 1364 | break; |
| 1365 | |
| 1366 | /* |
| 1367 | * Sanity check this iovec. 0 read succeeds. |
| 1368 | */ |
| 1369 | if (unlikely(!len)) |
| 1370 | break; |
| 1371 | if (unlikely(!base)) { |
| 1372 | error = -EFAULT; |
| 1373 | break; |
| 1374 | } |
| 1375 | |
Jens Axboe | 8811930 | 2008-02-08 08:49:14 -0800 | [diff] [blame] | 1376 | if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { |
| 1377 | error = -EFAULT; |
| 1378 | break; |
| 1379 | } |
| 1380 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1381 | sd.len = 0; |
| 1382 | sd.total_len = len; |
| 1383 | sd.flags = flags; |
| 1384 | sd.u.userptr = base; |
| 1385 | sd.pos = 0; |
| 1386 | |
| 1387 | size = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1388 | if (size < 0) { |
| 1389 | if (!ret) |
| 1390 | ret = size; |
| 1391 | |
| 1392 | break; |
| 1393 | } |
| 1394 | |
| 1395 | ret += size; |
| 1396 | |
| 1397 | if (size < len) |
| 1398 | break; |
| 1399 | |
| 1400 | nr_segs--; |
| 1401 | iov++; |
| 1402 | } |
| 1403 | |
| 1404 | if (pipe->inode) |
| 1405 | mutex_unlock(&pipe->inode->i_mutex); |
| 1406 | |
| 1407 | if (!ret) |
| 1408 | ret = error; |
| 1409 | |
| 1410 | return ret; |
| 1411 | } |
| 1412 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1413 | /* |
| 1414 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1415 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1416 | * to file). In both cases the output is a pipe, naturally. |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1417 | */ |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1418 | static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, |
| 1419 | unsigned long nr_segs, unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1420 | { |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1421 | struct pipe_inode_info *pipe; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1422 | struct page *pages[PIPE_BUFFERS]; |
| 1423 | struct partial_page partial[PIPE_BUFFERS]; |
| 1424 | struct splice_pipe_desc spd = { |
| 1425 | .pages = pages, |
| 1426 | .partial = partial, |
| 1427 | .flags = flags, |
| 1428 | .ops = &user_page_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 1429 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1430 | }; |
| 1431 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1432 | pipe = pipe_info(file->f_path.dentry->d_inode); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1433 | if (!pipe) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1434 | return -EBADF; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1435 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1436 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1437 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1438 | if (spd.nr_pages <= 0) |
| 1439 | return spd.nr_pages; |
| 1440 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1441 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1442 | } |
| 1443 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1444 | /* |
| 1445 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1446 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1447 | * operation that can be supported without any funky alignment restrictions |
| 1448 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1449 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1450 | * solutions for that: |
| 1451 | * |
| 1452 | * - memcpy() the data internally, at which point we might as well just |
| 1453 | * do a regular read() on the buffer anyway. |
| 1454 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1455 | * has restriction limitations on both ends of the pipe). |
| 1456 | * |
| 1457 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1458 | * |
| 1459 | */ |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1460 | asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov, |
| 1461 | unsigned long nr_segs, unsigned int flags) |
| 1462 | { |
| 1463 | struct file *file; |
| 1464 | long error; |
| 1465 | int fput; |
| 1466 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1467 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1468 | return -EINVAL; |
| 1469 | else if (unlikely(!nr_segs)) |
| 1470 | return 0; |
| 1471 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1472 | error = -EBADF; |
| 1473 | file = fget_light(fd, &fput); |
| 1474 | if (file) { |
| 1475 | if (file->f_mode & FMODE_WRITE) |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1476 | error = vmsplice_to_pipe(file, iov, nr_segs, flags); |
| 1477 | else if (file->f_mode & FMODE_READ) |
| 1478 | error = vmsplice_to_user(file, iov, nr_segs, flags); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1479 | |
| 1480 | fput_light(file, fput); |
| 1481 | } |
| 1482 | |
| 1483 | return error; |
| 1484 | } |
| 1485 | |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1486 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
| 1487 | int fd_out, loff_t __user *off_out, |
| 1488 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1489 | { |
| 1490 | long error; |
| 1491 | struct file *in, *out; |
| 1492 | int fput_in, fput_out; |
| 1493 | |
| 1494 | if (unlikely(!len)) |
| 1495 | return 0; |
| 1496 | |
| 1497 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1498 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1499 | if (in) { |
| 1500 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1501 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1502 | if (out) { |
| 1503 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1504 | error = do_splice(in, off_in, |
| 1505 | out, off_out, |
| 1506 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1507 | fput_light(out, fput_out); |
| 1508 | } |
| 1509 | } |
| 1510 | |
| 1511 | fput_light(in, fput_in); |
| 1512 | } |
| 1513 | |
| 1514 | return error; |
| 1515 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1516 | |
| 1517 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1518 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1519 | * return an appropriate error. |
| 1520 | */ |
| 1521 | static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1522 | { |
| 1523 | int ret; |
| 1524 | |
| 1525 | /* |
| 1526 | * Check ->nrbufs without the inode lock first. This function |
| 1527 | * is speculative anyways, so missing one is ok. |
| 1528 | */ |
| 1529 | if (pipe->nrbufs) |
| 1530 | return 0; |
| 1531 | |
| 1532 | ret = 0; |
| 1533 | mutex_lock(&pipe->inode->i_mutex); |
| 1534 | |
| 1535 | while (!pipe->nrbufs) { |
| 1536 | if (signal_pending(current)) { |
| 1537 | ret = -ERESTARTSYS; |
| 1538 | break; |
| 1539 | } |
| 1540 | if (!pipe->writers) |
| 1541 | break; |
| 1542 | if (!pipe->waiting_writers) { |
| 1543 | if (flags & SPLICE_F_NONBLOCK) { |
| 1544 | ret = -EAGAIN; |
| 1545 | break; |
| 1546 | } |
| 1547 | } |
| 1548 | pipe_wait(pipe); |
| 1549 | } |
| 1550 | |
| 1551 | mutex_unlock(&pipe->inode->i_mutex); |
| 1552 | return ret; |
| 1553 | } |
| 1554 | |
| 1555 | /* |
| 1556 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1557 | * return an appropriate error. |
| 1558 | */ |
| 1559 | static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1560 | { |
| 1561 | int ret; |
| 1562 | |
| 1563 | /* |
| 1564 | * Check ->nrbufs without the inode lock first. This function |
| 1565 | * is speculative anyways, so missing one is ok. |
| 1566 | */ |
| 1567 | if (pipe->nrbufs < PIPE_BUFFERS) |
| 1568 | return 0; |
| 1569 | |
| 1570 | ret = 0; |
| 1571 | mutex_lock(&pipe->inode->i_mutex); |
| 1572 | |
| 1573 | while (pipe->nrbufs >= PIPE_BUFFERS) { |
| 1574 | if (!pipe->readers) { |
| 1575 | send_sig(SIGPIPE, current, 0); |
| 1576 | ret = -EPIPE; |
| 1577 | break; |
| 1578 | } |
| 1579 | if (flags & SPLICE_F_NONBLOCK) { |
| 1580 | ret = -EAGAIN; |
| 1581 | break; |
| 1582 | } |
| 1583 | if (signal_pending(current)) { |
| 1584 | ret = -ERESTARTSYS; |
| 1585 | break; |
| 1586 | } |
| 1587 | pipe->waiting_writers++; |
| 1588 | pipe_wait(pipe); |
| 1589 | pipe->waiting_writers--; |
| 1590 | } |
| 1591 | |
| 1592 | mutex_unlock(&pipe->inode->i_mutex); |
| 1593 | return ret; |
| 1594 | } |
| 1595 | |
| 1596 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1597 | * Link contents of ipipe to opipe. |
| 1598 | */ |
| 1599 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1600 | struct pipe_inode_info *opipe, |
| 1601 | size_t len, unsigned int flags) |
| 1602 | { |
| 1603 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1604 | int ret = 0, i = 0, nbuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1605 | |
| 1606 | /* |
| 1607 | * Potential ABBA deadlock, work around it by ordering lock |
| 1608 | * grabbing by inode address. Otherwise two different processes |
| 1609 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1610 | */ |
Mark Fasheh | 62752ee | 2006-10-17 10:31:38 +0200 | [diff] [blame] | 1611 | inode_double_lock(ipipe->inode, opipe->inode); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1612 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1613 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1614 | if (!opipe->readers) { |
| 1615 | send_sig(SIGPIPE, current, 0); |
| 1616 | if (!ret) |
| 1617 | ret = -EPIPE; |
| 1618 | break; |
| 1619 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1620 | |
| 1621 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1622 | * If we have iterated all input buffers or ran out of |
| 1623 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1624 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1625 | if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1626 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1627 | |
| 1628 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1629 | nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1630 | |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1631 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1632 | * Get a reference to this pipe buffer, |
| 1633 | * so we can copy the contents over. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1634 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1635 | ibuf->ops->get(ipipe, ibuf); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1636 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1637 | obuf = opipe->bufs + nbuf; |
| 1638 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1639 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1640 | /* |
| 1641 | * Don't inherit the gift flag, we need to |
| 1642 | * prevent multiple steals of this page. |
| 1643 | */ |
| 1644 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1645 | |
| 1646 | if (obuf->len > len) |
| 1647 | obuf->len = len; |
| 1648 | |
| 1649 | opipe->nrbufs++; |
| 1650 | ret += obuf->len; |
| 1651 | len -= obuf->len; |
| 1652 | i++; |
| 1653 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1654 | |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1655 | /* |
| 1656 | * return EAGAIN if we have the potential of some data in the |
| 1657 | * future, otherwise just return 0 |
| 1658 | */ |
| 1659 | if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) |
| 1660 | ret = -EAGAIN; |
| 1661 | |
Mark Fasheh | 62752ee | 2006-10-17 10:31:38 +0200 | [diff] [blame] | 1662 | inode_double_unlock(ipipe->inode, opipe->inode); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1663 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1664 | /* |
| 1665 | * If we put data in the output pipe, wakeup any potential readers. |
| 1666 | */ |
| 1667 | if (ret > 0) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1668 | smp_mb(); |
| 1669 | if (waitqueue_active(&opipe->wait)) |
| 1670 | wake_up_interruptible(&opipe->wait); |
| 1671 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1672 | } |
| 1673 | |
| 1674 | return ret; |
| 1675 | } |
| 1676 | |
| 1677 | /* |
| 1678 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1679 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1680 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1681 | * applicable one is SPLICE_F_NONBLOCK. |
| 1682 | */ |
| 1683 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1684 | unsigned int flags) |
| 1685 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1686 | struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1687 | struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1688 | int ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1689 | |
| 1690 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1691 | * Duplicate the contents of ipipe to opipe without actually |
| 1692 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1693 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1694 | if (ipipe && opipe && ipipe != opipe) { |
| 1695 | /* |
| 1696 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1697 | * ordering doesn't really matter. |
| 1698 | */ |
| 1699 | ret = link_ipipe_prep(ipipe, flags); |
| 1700 | if (!ret) { |
| 1701 | ret = link_opipe_prep(opipe, flags); |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1702 | if (!ret) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1703 | ret = link_pipe(ipipe, opipe, len, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1704 | } |
| 1705 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1706 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1707 | return ret; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1708 | } |
| 1709 | |
| 1710 | asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags) |
| 1711 | { |
| 1712 | struct file *in; |
| 1713 | int error, fput_in; |
| 1714 | |
| 1715 | if (unlikely(!len)) |
| 1716 | return 0; |
| 1717 | |
| 1718 | error = -EBADF; |
| 1719 | in = fget_light(fdin, &fput_in); |
| 1720 | if (in) { |
| 1721 | if (in->f_mode & FMODE_READ) { |
| 1722 | int fput_out; |
| 1723 | struct file *out = fget_light(fdout, &fput_out); |
| 1724 | |
| 1725 | if (out) { |
| 1726 | if (out->f_mode & FMODE_WRITE) |
| 1727 | error = do_tee(in, out, len, flags); |
| 1728 | fput_light(out, fput_out); |
| 1729 | } |
| 1730 | } |
| 1731 | fput_light(in, fput_in); |
| 1732 | } |
| 1733 | |
| 1734 | return error; |
| 1735 | } |