Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1 | /* |
| 2 | * "splice": joining two ropes together by interweaving their strands. |
| 3 | * |
| 4 | * This is the "extended pipe" functionality, where a pipe is used as |
| 5 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel |
| 6 | * buffer that you can use to transfer data from one end to the other. |
| 7 | * |
| 8 | * The traditional unix read/write is extended with a "splice()" operation |
| 9 | * that transfers data buffers to or from a pipe buffer. |
| 10 | * |
| 11 | * Named by Larry McVoy, original implementation from Linus, extended by |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 12 | * Jens to support splicing to files, network, direct splicing, etc and |
| 13 | * fixing lots of bugs. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 14 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
Jens Axboe | c2058e0 | 2006-04-11 13:56:34 +0200 | [diff] [blame] | 16 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
| 17 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 18 | * |
| 19 | */ |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/file.h> |
| 22 | #include <linux/pagemap.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 23 | #include <linux/splice.h> |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 24 | #include <linux/memcontrol.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 25 | #include <linux/mm_inline.h> |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 26 | #include <linux/swap.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 27 | #include <linux/writeback.h> |
| 28 | #include <linux/buffer_head.h> |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 29 | #include <linux/module.h> |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 30 | #include <linux/syscalls.h> |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 31 | #include <linux/uio.h> |
James Morris | 29ce205 | 2007-07-13 11:44:32 +0200 | [diff] [blame] | 32 | #include <linux/security.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 33 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 34 | /* |
| 35 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 36 | * a vm helper function, it's already simplified quite a bit by the |
| 37 | * addition of remove_mapping(). If success is returned, the caller may |
| 38 | * attempt to reuse this page for another destination. |
| 39 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 40 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 41 | struct pipe_buffer *buf) |
| 42 | { |
| 43 | struct page *page = buf->page; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 44 | struct address_space *mapping; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 45 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 46 | lock_page(page); |
| 47 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 48 | mapping = page_mapping(page); |
| 49 | if (mapping) { |
| 50 | WARN_ON(!PageUptodate(page)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 51 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 52 | /* |
| 53 | * At least for ext2 with nobh option, we need to wait on |
| 54 | * writeback completing on this page, since we'll remove it |
| 55 | * from the pagecache. Otherwise truncate wont wait on the |
| 56 | * page, allowing the disk blocks to be reused by someone else |
| 57 | * before we actually wrote our data to them. fs corruption |
| 58 | * ensues. |
| 59 | */ |
| 60 | wait_on_page_writeback(page); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 61 | |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 62 | if (page_has_private(page) && |
| 63 | !try_to_release_page(page, GFP_KERNEL)) |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 64 | goto out_unlock; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 65 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 66 | /* |
| 67 | * If we succeeded in removing the mapping, set LRU flag |
| 68 | * and return good. |
| 69 | */ |
| 70 | if (remove_mapping(mapping, page)) { |
| 71 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 72 | return 0; |
| 73 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 74 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 75 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 76 | /* |
| 77 | * Raced with truncate or failed to remove page from current |
| 78 | * address space, unlock and return failure. |
| 79 | */ |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 80 | out_unlock: |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 81 | unlock_page(page); |
| 82 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 83 | } |
| 84 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 85 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 86 | struct pipe_buffer *buf) |
| 87 | { |
| 88 | page_cache_release(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 89 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 90 | } |
| 91 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 92 | /* |
| 93 | * Check whether the contents of buf is OK to access. Since the content |
| 94 | * is a page cache page, IO may be in flight. |
| 95 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 96 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 97 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 98 | { |
| 99 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 100 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 101 | |
| 102 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 103 | lock_page(page); |
| 104 | |
| 105 | /* |
| 106 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 107 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 108 | */ |
| 109 | if (!page->mapping) { |
| 110 | err = -ENODATA; |
| 111 | goto error; |
| 112 | } |
| 113 | |
| 114 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 115 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 116 | */ |
| 117 | if (!PageUptodate(page)) { |
| 118 | err = -EIO; |
| 119 | goto error; |
| 120 | } |
| 121 | |
| 122 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 123 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 124 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 125 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 126 | } |
| 127 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 128 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 129 | error: |
| 130 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 131 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 132 | } |
| 133 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 134 | static const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 135 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 136 | .map = generic_pipe_buf_map, |
| 137 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 138 | .confirm = page_cache_pipe_buf_confirm, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 139 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 140 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 141 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 142 | }; |
| 143 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 144 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 145 | struct pipe_buffer *buf) |
| 146 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 147 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 148 | return 1; |
| 149 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 150 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 151 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 152 | } |
| 153 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 154 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 155 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 156 | .map = generic_pipe_buf_map, |
| 157 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 158 | .confirm = generic_pipe_buf_confirm, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 159 | .release = page_cache_pipe_buf_release, |
| 160 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 161 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 162 | }; |
| 163 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 164 | /** |
| 165 | * splice_to_pipe - fill passed data into a pipe |
| 166 | * @pipe: pipe to fill |
| 167 | * @spd: data to fill |
| 168 | * |
| 169 | * Description: |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 170 | * @spd contains a map of pages and len/offset tuples, along with |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 171 | * the struct pipe_buf_operations associated with these pages. This |
| 172 | * function will link that data to the pipe. |
| 173 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 174 | */ |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 175 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 176 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 177 | { |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 178 | unsigned int spd_pages = spd->nr_pages; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 179 | int ret, do_wakeup, page_nr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 180 | |
| 181 | ret = 0; |
| 182 | do_wakeup = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 183 | page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 184 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 185 | pipe_lock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 186 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 187 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 188 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 189 | send_sig(SIGPIPE, current, 0); |
| 190 | if (!ret) |
| 191 | ret = -EPIPE; |
| 192 | break; |
| 193 | } |
| 194 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 195 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 196 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 197 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 198 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 199 | buf->page = spd->pages[page_nr]; |
| 200 | buf->offset = spd->partial[page_nr].offset; |
| 201 | buf->len = spd->partial[page_nr].len; |
Jens Axboe | 497f962 | 2007-06-11 12:00:45 +0200 | [diff] [blame] | 202 | buf->private = spd->partial[page_nr].private; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 203 | buf->ops = spd->ops; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 204 | if (spd->flags & SPLICE_F_GIFT) |
| 205 | buf->flags |= PIPE_BUF_FLAG_GIFT; |
| 206 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 207 | pipe->nrbufs++; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 208 | page_nr++; |
| 209 | ret += buf->len; |
| 210 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 211 | if (pipe->inode) |
| 212 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 213 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 214 | if (!--spd->nr_pages) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 215 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 216 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 217 | continue; |
| 218 | |
| 219 | break; |
| 220 | } |
| 221 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 222 | if (spd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 223 | if (!ret) |
| 224 | ret = -EAGAIN; |
| 225 | break; |
| 226 | } |
| 227 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 228 | if (signal_pending(current)) { |
| 229 | if (!ret) |
| 230 | ret = -ERESTARTSYS; |
| 231 | break; |
| 232 | } |
| 233 | |
| 234 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 235 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 236 | if (waitqueue_active(&pipe->wait)) |
| 237 | wake_up_interruptible_sync(&pipe->wait); |
| 238 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 239 | do_wakeup = 0; |
| 240 | } |
| 241 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 242 | pipe->waiting_writers++; |
| 243 | pipe_wait(pipe); |
| 244 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 245 | } |
| 246 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 247 | pipe_unlock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 248 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 249 | if (do_wakeup) { |
| 250 | smp_mb(); |
| 251 | if (waitqueue_active(&pipe->wait)) |
| 252 | wake_up_interruptible(&pipe->wait); |
| 253 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 254 | } |
| 255 | |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 256 | while (page_nr < spd_pages) |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 257 | spd->spd_release(spd, page_nr++); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 258 | |
| 259 | return ret; |
| 260 | } |
| 261 | |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 262 | static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) |
| 263 | { |
| 264 | page_cache_release(spd->pages[i]); |
| 265 | } |
| 266 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 267 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 268 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 269 | struct pipe_inode_info *pipe, size_t len, |
| 270 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 271 | { |
| 272 | struct address_space *mapping = in->f_mapping; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 273 | unsigned int loff, nr_pages, req_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 274 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 275 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 276 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 277 | pgoff_t index, end_index; |
| 278 | loff_t isize; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 279 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 280 | struct splice_pipe_desc spd = { |
| 281 | .pages = pages, |
| 282 | .partial = partial, |
| 283 | .flags = flags, |
| 284 | .ops = &page_cache_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 285 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 286 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 287 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 288 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 289 | loff = *ppos & ~PAGE_CACHE_MASK; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 290 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 291 | nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 292 | |
| 293 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 294 | * Lookup the (hopefully) full range of pages we need. |
| 295 | */ |
| 296 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 297 | index += spd.nr_pages; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 298 | |
| 299 | /* |
| 300 | * If find_get_pages_contig() returned fewer pages than we needed, |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 301 | * readahead/allocate the rest and fill in the holes. |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 302 | */ |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 303 | if (spd.nr_pages < nr_pages) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 304 | page_cache_sync_readahead(mapping, &in->f_ra, in, |
| 305 | index, req_pages - spd.nr_pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 306 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 307 | error = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 308 | while (spd.nr_pages < nr_pages) { |
| 309 | /* |
| 310 | * Page could be there, find_get_pages_contig() breaks on |
| 311 | * the first hole. |
| 312 | */ |
| 313 | page = find_get_page(mapping, index); |
| 314 | if (!page) { |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 315 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 316 | * page didn't exist, allocate one. |
| 317 | */ |
| 318 | page = page_cache_alloc_cold(mapping); |
| 319 | if (!page) |
| 320 | break; |
| 321 | |
| 322 | error = add_to_page_cache_lru(page, mapping, index, |
Hugh Dickins | 4cd1350 | 2008-04-03 23:35:22 +0100 | [diff] [blame] | 323 | mapping_gfp_mask(mapping)); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 324 | if (unlikely(error)) { |
| 325 | page_cache_release(page); |
Jens Axboe | a054887 | 2006-05-03 10:58:22 +0200 | [diff] [blame] | 326 | if (error == -EEXIST) |
| 327 | continue; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 328 | break; |
| 329 | } |
| 330 | /* |
| 331 | * add_to_page_cache() locks the page, unlock it |
| 332 | * to avoid convoluting the logic below even more. |
| 333 | */ |
| 334 | unlock_page(page); |
| 335 | } |
| 336 | |
| 337 | pages[spd.nr_pages++] = page; |
| 338 | index++; |
| 339 | } |
| 340 | |
| 341 | /* |
| 342 | * Now loop over the map and see if we need to start IO on any |
| 343 | * pages, fill in the partial map, etc. |
| 344 | */ |
| 345 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 346 | nr_pages = spd.nr_pages; |
| 347 | spd.nr_pages = 0; |
| 348 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 349 | unsigned int this_len; |
| 350 | |
| 351 | if (!len) |
| 352 | break; |
| 353 | |
| 354 | /* |
| 355 | * this_len is the max we'll use from this page |
| 356 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 357 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 358 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 359 | |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 360 | if (PageReadahead(page)) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 361 | page_cache_async_readahead(mapping, &in->f_ra, in, |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 362 | page, index, req_pages - page_nr); |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 363 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 364 | /* |
| 365 | * If the page isn't uptodate, we may need to start io on it |
| 366 | */ |
| 367 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 368 | /* |
| 369 | * If in nonblock mode then dont block on waiting |
| 370 | * for an in-flight io page |
| 371 | */ |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 372 | if (flags & SPLICE_F_NONBLOCK) { |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 373 | if (!trylock_page(page)) { |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 374 | error = -EAGAIN; |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 375 | break; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 376 | } |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 377 | } else |
| 378 | lock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 379 | |
| 380 | /* |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 381 | * Page was truncated, or invalidated by the |
| 382 | * filesystem. Redo the find/create, but this time the |
| 383 | * page is kept locked, so there's no chance of another |
| 384 | * race with truncate/invalidate. |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 385 | */ |
| 386 | if (!page->mapping) { |
| 387 | unlock_page(page); |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 388 | page = find_or_create_page(mapping, index, |
| 389 | mapping_gfp_mask(mapping)); |
| 390 | |
| 391 | if (!page) { |
| 392 | error = -ENOMEM; |
| 393 | break; |
| 394 | } |
| 395 | page_cache_release(pages[page_nr]); |
| 396 | pages[page_nr] = page; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 397 | } |
| 398 | /* |
| 399 | * page was already under io and is now done, great |
| 400 | */ |
| 401 | if (PageUptodate(page)) { |
| 402 | unlock_page(page); |
| 403 | goto fill_it; |
| 404 | } |
| 405 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 406 | /* |
| 407 | * need to read in the page |
| 408 | */ |
| 409 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 410 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 411 | /* |
| 412 | * We really should re-lookup the page here, |
| 413 | * but it complicates things a lot. Instead |
| 414 | * lets just do what we already stored, and |
| 415 | * we'll get it the next time we are called. |
| 416 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 417 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 418 | error = 0; |
| 419 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 420 | break; |
| 421 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 422 | } |
| 423 | fill_it: |
| 424 | /* |
| 425 | * i_size must be checked after PageUptodate. |
| 426 | */ |
| 427 | isize = i_size_read(mapping->host); |
| 428 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 429 | if (unlikely(!isize || index > end_index)) |
| 430 | break; |
| 431 | |
| 432 | /* |
| 433 | * if this is the last page, see if we need to shrink |
| 434 | * the length and stop |
| 435 | */ |
| 436 | if (end_index == index) { |
| 437 | unsigned int plen; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 438 | |
| 439 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 440 | * max good bytes in this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 441 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 442 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 443 | if (plen <= loff) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 444 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 445 | |
| 446 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 447 | * force quit after adding this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 448 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 449 | this_len = min(this_len, plen - loff); |
| 450 | len = this_len; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 451 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 452 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 453 | partial[page_nr].offset = loff; |
| 454 | partial[page_nr].len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 455 | len -= this_len; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 456 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 457 | spd.nr_pages++; |
| 458 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 459 | } |
| 460 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 461 | /* |
Hugh Dickins | 475ecad | 2007-06-07 09:36:00 +0200 | [diff] [blame] | 462 | * Release any pages at the end, if we quit early. 'page_nr' is how far |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 463 | * we got, 'nr_pages' is how many pages are in the map. |
| 464 | */ |
| 465 | while (page_nr < nr_pages) |
| 466 | page_cache_release(pages[page_nr++]); |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 467 | in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 468 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 469 | if (spd.nr_pages) |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 470 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 471 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 472 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 473 | } |
| 474 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 475 | /** |
| 476 | * generic_file_splice_read - splice data from file to a pipe |
| 477 | * @in: file to splice from |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 478 | * @ppos: position in @in |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 479 | * @pipe: pipe to splice to |
| 480 | * @len: number of bytes to splice |
| 481 | * @flags: splice modifier flags |
| 482 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 483 | * Description: |
| 484 | * Will read pages from given file and fill them into a pipe. Can be |
| 485 | * used as long as the address_space operations for the source implements |
| 486 | * a readpage() hook. |
| 487 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 488 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 489 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 490 | struct pipe_inode_info *pipe, size_t len, |
| 491 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 492 | { |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 493 | loff_t isize, left; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 494 | int ret; |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 495 | |
| 496 | isize = i_size_read(in->f_mapping->host); |
| 497 | if (unlikely(*ppos >= isize)) |
| 498 | return 0; |
| 499 | |
| 500 | left = isize - *ppos; |
| 501 | if (unlikely(left < len)) |
| 502 | len = left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 503 | |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 504 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
| 505 | if (ret > 0) |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 506 | *ppos += ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 507 | |
| 508 | return ret; |
| 509 | } |
| 510 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 511 | EXPORT_SYMBOL(generic_file_splice_read); |
| 512 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 513 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 514 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 515 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 516 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 517 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 518 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 519 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 520 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 521 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 522 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 523 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 524 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 525 | if (!ret) { |
| 526 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 527 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 528 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 529 | sd->len, &pos, more); |
| 530 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 531 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 532 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 533 | } |
| 534 | |
| 535 | /* |
| 536 | * This is a little more tricky than the file -> pipe splicing. There are |
| 537 | * basically three cases: |
| 538 | * |
| 539 | * - Destination page already exists in the address space and there |
| 540 | * are users of it. For that case we have no other option that |
| 541 | * copying the data. Tough luck. |
| 542 | * - Destination page already exists in the address space, but there |
| 543 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 544 | * through to last case. |
| 545 | * - Destination page does not exist, we can add the pipe page to |
| 546 | * the page cache and avoid the copy. |
| 547 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 548 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 549 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 550 | * file address space page cache. This is possible if no one else has |
| 551 | * the pipe page referenced outside of the pipe and page cache. If |
| 552 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 553 | * a new page in the output file page cache and fill/dirty that. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 554 | */ |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 555 | int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 556 | struct splice_desc *sd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 557 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 558 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 559 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 560 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 561 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 562 | void *fsdata; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 563 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 564 | |
| 565 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 566 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 567 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 568 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 569 | if (unlikely(ret)) |
| 570 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 571 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 572 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 573 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 574 | this_len = sd->len; |
| 575 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 576 | this_len = PAGE_CACHE_SIZE - offset; |
| 577 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 578 | ret = pagecache_write_begin(file, mapping, sd->pos, this_len, |
| 579 | AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); |
| 580 | if (unlikely(ret)) |
| 581 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 582 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 583 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 584 | /* |
| 585 | * Careful, ->map() uses KM_USER0! |
| 586 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 587 | char *src = buf->ops->map(pipe, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 588 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 589 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 590 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 591 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 592 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 593 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 594 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 595 | ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, |
| 596 | page, fsdata); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 597 | out: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 598 | return ret; |
| 599 | } |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 600 | EXPORT_SYMBOL(pipe_to_file); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 601 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 602 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
| 603 | { |
| 604 | smp_mb(); |
| 605 | if (waitqueue_active(&pipe->wait)) |
| 606 | wake_up_interruptible(&pipe->wait); |
| 607 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
| 608 | } |
| 609 | |
| 610 | /** |
| 611 | * splice_from_pipe_feed - feed available data from a pipe to a file |
| 612 | * @pipe: pipe to splice from |
| 613 | * @sd: information to @actor |
| 614 | * @actor: handler that splices the data |
| 615 | * |
| 616 | * Description: |
| 617 | |
| 618 | * This function loops over the pipe and calls @actor to do the |
| 619 | * actual moving of a single struct pipe_buffer to the desired |
| 620 | * destination. It returns when there's no more buffers left in |
| 621 | * the pipe or if the requested number of bytes (@sd->total_len) |
| 622 | * have been copied. It returns a positive number (one) if the |
| 623 | * pipe needs to be filled with more data, zero if the required |
| 624 | * number of bytes have been copied and -errno on error. |
| 625 | * |
| 626 | * This, together with splice_from_pipe_{begin,end,next}, may be |
| 627 | * used to implement the functionality of __splice_from_pipe() when |
| 628 | * locking is required around copying the pipe buffers to the |
| 629 | * destination. |
| 630 | */ |
| 631 | int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 632 | splice_actor *actor) |
| 633 | { |
| 634 | int ret; |
| 635 | |
| 636 | while (pipe->nrbufs) { |
| 637 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
| 638 | const struct pipe_buf_operations *ops = buf->ops; |
| 639 | |
| 640 | sd->len = buf->len; |
| 641 | if (sd->len > sd->total_len) |
| 642 | sd->len = sd->total_len; |
| 643 | |
| 644 | ret = actor(pipe, buf, sd); |
| 645 | if (ret <= 0) { |
| 646 | if (ret == -ENODATA) |
| 647 | ret = 0; |
| 648 | return ret; |
| 649 | } |
| 650 | buf->offset += ret; |
| 651 | buf->len -= ret; |
| 652 | |
| 653 | sd->num_spliced += ret; |
| 654 | sd->len -= ret; |
| 655 | sd->pos += ret; |
| 656 | sd->total_len -= ret; |
| 657 | |
| 658 | if (!buf->len) { |
| 659 | buf->ops = NULL; |
| 660 | ops->release(pipe, buf); |
| 661 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 662 | pipe->nrbufs--; |
| 663 | if (pipe->inode) |
| 664 | sd->need_wakeup = true; |
| 665 | } |
| 666 | |
| 667 | if (!sd->total_len) |
| 668 | return 0; |
| 669 | } |
| 670 | |
| 671 | return 1; |
| 672 | } |
| 673 | EXPORT_SYMBOL(splice_from_pipe_feed); |
| 674 | |
| 675 | /** |
| 676 | * splice_from_pipe_next - wait for some data to splice from |
| 677 | * @pipe: pipe to splice from |
| 678 | * @sd: information about the splice operation |
| 679 | * |
| 680 | * Description: |
| 681 | * This function will wait for some data and return a positive |
| 682 | * value (one) if pipe buffers are available. It will return zero |
| 683 | * or -errno if no more data needs to be spliced. |
| 684 | */ |
| 685 | int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 686 | { |
| 687 | while (!pipe->nrbufs) { |
| 688 | if (!pipe->writers) |
| 689 | return 0; |
| 690 | |
| 691 | if (!pipe->waiting_writers && sd->num_spliced) |
| 692 | return 0; |
| 693 | |
| 694 | if (sd->flags & SPLICE_F_NONBLOCK) |
| 695 | return -EAGAIN; |
| 696 | |
| 697 | if (signal_pending(current)) |
| 698 | return -ERESTARTSYS; |
| 699 | |
| 700 | if (sd->need_wakeup) { |
| 701 | wakeup_pipe_writers(pipe); |
| 702 | sd->need_wakeup = false; |
| 703 | } |
| 704 | |
| 705 | pipe_wait(pipe); |
| 706 | } |
| 707 | |
| 708 | return 1; |
| 709 | } |
| 710 | EXPORT_SYMBOL(splice_from_pipe_next); |
| 711 | |
| 712 | /** |
| 713 | * splice_from_pipe_begin - start splicing from pipe |
| 714 | * @pipe: pipe to splice from |
| 715 | * |
| 716 | * Description: |
| 717 | * This function should be called before a loop containing |
| 718 | * splice_from_pipe_next() and splice_from_pipe_feed() to |
| 719 | * initialize the necessary fields of @sd. |
| 720 | */ |
| 721 | void splice_from_pipe_begin(struct splice_desc *sd) |
| 722 | { |
| 723 | sd->num_spliced = 0; |
| 724 | sd->need_wakeup = false; |
| 725 | } |
| 726 | EXPORT_SYMBOL(splice_from_pipe_begin); |
| 727 | |
| 728 | /** |
| 729 | * splice_from_pipe_end - finish splicing from pipe |
| 730 | * @pipe: pipe to splice from |
| 731 | * @sd: information about the splice operation |
| 732 | * |
| 733 | * Description: |
| 734 | * This function will wake up pipe writers if necessary. It should |
| 735 | * be called after a loop containing splice_from_pipe_next() and |
| 736 | * splice_from_pipe_feed(). |
| 737 | */ |
| 738 | void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 739 | { |
| 740 | if (sd->need_wakeup) |
| 741 | wakeup_pipe_writers(pipe); |
| 742 | } |
| 743 | EXPORT_SYMBOL(splice_from_pipe_end); |
| 744 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 745 | /** |
| 746 | * __splice_from_pipe - splice data from a pipe to given actor |
| 747 | * @pipe: pipe to splice from |
| 748 | * @sd: information to @actor |
| 749 | * @actor: handler that splices the data |
| 750 | * |
| 751 | * Description: |
| 752 | * This function does little more than loop over the pipe and call |
| 753 | * @actor to do the actual moving of a single struct pipe_buffer to |
| 754 | * the desired destination. See pipe_to_file, pipe_to_sendpage, or |
| 755 | * pipe_to_user. |
| 756 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 757 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 758 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 759 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 760 | { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 761 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 762 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 763 | splice_from_pipe_begin(sd); |
| 764 | do { |
| 765 | ret = splice_from_pipe_next(pipe, sd); |
| 766 | if (ret > 0) |
| 767 | ret = splice_from_pipe_feed(pipe, sd, actor); |
| 768 | } while (ret > 0); |
| 769 | splice_from_pipe_end(pipe, sd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 770 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 771 | return sd->num_spliced ? sd->num_spliced : ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 772 | } |
Mark Fasheh | 40bee44 | 2007-03-21 13:11:02 +0100 | [diff] [blame] | 773 | EXPORT_SYMBOL(__splice_from_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 774 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 775 | /** |
| 776 | * splice_from_pipe - splice data from a pipe to a file |
| 777 | * @pipe: pipe to splice from |
| 778 | * @out: file to splice to |
| 779 | * @ppos: position in @out |
| 780 | * @len: how many bytes to splice |
| 781 | * @flags: splice modifier flags |
| 782 | * @actor: handler that splices the data |
| 783 | * |
| 784 | * Description: |
Miklos Szeredi | 2933970 | 2009-04-14 19:48:37 +0200 | [diff] [blame] | 785 | * See __splice_from_pipe. This function locks the pipe inode, |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 786 | * otherwise it's identical to __splice_from_pipe(). |
| 787 | * |
| 788 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 789 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 790 | loff_t *ppos, size_t len, unsigned int flags, |
| 791 | splice_actor *actor) |
| 792 | { |
| 793 | ssize_t ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 794 | struct splice_desc sd = { |
| 795 | .total_len = len, |
| 796 | .flags = flags, |
| 797 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 798 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 799 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 800 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 801 | pipe_lock(pipe); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 802 | ret = __splice_from_pipe(pipe, &sd, actor); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 803 | pipe_unlock(pipe); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 804 | |
| 805 | return ret; |
| 806 | } |
| 807 | |
| 808 | /** |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 809 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 810 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 811 | * @out: file to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 812 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 813 | * @len: number of bytes to splice |
| 814 | * @flags: splice modifier flags |
| 815 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 816 | * Description: |
| 817 | * Will either move or copy pages (determined by @flags options) from |
| 818 | * the given pipe inode to the given file. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 819 | * |
| 820 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 821 | ssize_t |
| 822 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 823 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 824 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 825 | struct address_space *mapping = out->f_mapping; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 826 | struct inode *inode = mapping->host; |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 827 | struct splice_desc sd = { |
| 828 | .total_len = len, |
| 829 | .flags = flags, |
| 830 | .pos = *ppos, |
| 831 | .u.file = out, |
| 832 | }; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 833 | ssize_t ret; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 834 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 835 | pipe_lock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 836 | |
| 837 | splice_from_pipe_begin(&sd); |
| 838 | do { |
| 839 | ret = splice_from_pipe_next(pipe, &sd); |
| 840 | if (ret <= 0) |
| 841 | break; |
| 842 | |
| 843 | mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); |
| 844 | ret = file_remove_suid(out); |
| 845 | if (!ret) |
| 846 | ret = splice_from_pipe_feed(pipe, &sd, pipe_to_file); |
| 847 | mutex_unlock(&inode->i_mutex); |
| 848 | } while (ret > 0); |
| 849 | splice_from_pipe_end(pipe, &sd); |
| 850 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 851 | pipe_unlock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 852 | |
| 853 | if (sd.num_spliced) |
| 854 | ret = sd.num_spliced; |
| 855 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 856 | if (ret > 0) { |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 857 | unsigned long nr_pages; |
| 858 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 859 | *ppos += ret; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 860 | nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 861 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 862 | /* |
| 863 | * If file or inode is SYNC and we actually wrote some data, |
| 864 | * sync it. |
| 865 | */ |
| 866 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 867 | int err; |
| 868 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 869 | mutex_lock(&inode->i_mutex); |
| 870 | err = generic_osync_inode(inode, mapping, |
| 871 | OSYNC_METADATA|OSYNC_DATA); |
| 872 | mutex_unlock(&inode->i_mutex); |
| 873 | |
| 874 | if (err) |
| 875 | ret = err; |
| 876 | } |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 877 | balance_dirty_pages_ratelimited_nr(mapping, nr_pages); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 878 | } |
| 879 | |
| 880 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 881 | } |
| 882 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 883 | EXPORT_SYMBOL(generic_file_splice_write); |
| 884 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 885 | /** |
| 886 | * generic_splice_sendpage - splice data from a pipe to a socket |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 887 | * @pipe: pipe to splice from |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 888 | * @out: socket to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 889 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 890 | * @len: number of bytes to splice |
| 891 | * @flags: splice modifier flags |
| 892 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 893 | * Description: |
| 894 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 895 | * is involved. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 896 | * |
| 897 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 898 | 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] | 899 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 900 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 901 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 902 | } |
| 903 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 904 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 905 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 906 | /* |
| 907 | * Attempt to initiate a splice from pipe to file. |
| 908 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 909 | 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] | 910 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 911 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 912 | int ret; |
| 913 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 914 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 915 | return -EINVAL; |
| 916 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 917 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 918 | return -EBADF; |
| 919 | |
Linus Torvalds | efc968d | 2008-10-09 14:04:54 -0700 | [diff] [blame] | 920 | if (unlikely(out->f_flags & O_APPEND)) |
| 921 | return -EINVAL; |
| 922 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 923 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 924 | if (unlikely(ret < 0)) |
| 925 | return ret; |
| 926 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 927 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 928 | } |
| 929 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 930 | /* |
| 931 | * Attempt to initiate a splice from a file to a pipe. |
| 932 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 933 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 934 | struct pipe_inode_info *pipe, size_t len, |
| 935 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 936 | { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 937 | int ret; |
| 938 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 939 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 940 | return -EINVAL; |
| 941 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 942 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 943 | return -EBADF; |
| 944 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 945 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 946 | if (unlikely(ret < 0)) |
| 947 | return ret; |
| 948 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 949 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 950 | } |
| 951 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 952 | /** |
| 953 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 954 | * @in: file to splice from |
| 955 | * @sd: actor information on where to splice to |
| 956 | * @actor: handles the data splicing |
| 957 | * |
| 958 | * Description: |
| 959 | * This is a special case helper to splice directly between two |
| 960 | * points, without requiring an explicit pipe. Internally an allocated |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 961 | * pipe is cached in the process, and reused during the lifetime of |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 962 | * that process. |
| 963 | * |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 964 | */ |
| 965 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 966 | splice_direct_actor *actor) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 967 | { |
| 968 | struct pipe_inode_info *pipe; |
| 969 | long ret, bytes; |
| 970 | umode_t i_mode; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 971 | size_t len; |
| 972 | int i, flags; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 973 | |
| 974 | /* |
| 975 | * We require the input being a regular file, as we don't want to |
| 976 | * randomly drop data for eg socket -> socket splicing. Use the |
| 977 | * piped splicing for that! |
| 978 | */ |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 979 | i_mode = in->f_path.dentry->d_inode->i_mode; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 980 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 981 | return -EINVAL; |
| 982 | |
| 983 | /* |
| 984 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 985 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 986 | */ |
| 987 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 988 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 989 | pipe = alloc_pipe_info(NULL); |
| 990 | if (!pipe) |
| 991 | return -ENOMEM; |
| 992 | |
| 993 | /* |
| 994 | * 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] | 995 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 996 | * PIPE_READERS appropriately. |
| 997 | */ |
| 998 | pipe->readers = 1; |
| 999 | |
| 1000 | current->splice_pipe = pipe; |
| 1001 | } |
| 1002 | |
| 1003 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 1004 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1005 | */ |
| 1006 | ret = 0; |
| 1007 | bytes = 0; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1008 | len = sd->total_len; |
| 1009 | flags = sd->flags; |
| 1010 | |
| 1011 | /* |
| 1012 | * Don't block on output, we have to drain the direct pipe. |
| 1013 | */ |
| 1014 | sd->flags &= ~SPLICE_F_NONBLOCK; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1015 | |
| 1016 | while (len) { |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1017 | size_t read_len; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1018 | loff_t pos = sd->pos, prev_pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1019 | |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1020 | ret = do_splice_to(in, &pos, pipe, len, flags); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1021 | if (unlikely(ret <= 0)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1022 | goto out_release; |
| 1023 | |
| 1024 | read_len = ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1025 | sd->total_len = read_len; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1026 | |
| 1027 | /* |
| 1028 | * NOTE: nonblocking mode only applies to the input. We |
| 1029 | * must not do the output in nonblocking mode as then we |
| 1030 | * could get stuck data in the internal pipe: |
| 1031 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1032 | ret = actor(pipe, sd); |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1033 | if (unlikely(ret <= 0)) { |
| 1034 | sd->pos = prev_pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1035 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1036 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1037 | |
| 1038 | bytes += ret; |
| 1039 | len -= ret; |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1040 | sd->pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1041 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1042 | if (ret < read_len) { |
| 1043 | sd->pos = prev_pos + ret; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1044 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1045 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1046 | } |
| 1047 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1048 | done: |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1049 | pipe->nrbufs = pipe->curbuf = 0; |
Jens Axboe | 8084870 | 2008-01-30 12:24:48 +0100 | [diff] [blame] | 1050 | file_accessed(in); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1051 | return bytes; |
| 1052 | |
| 1053 | out_release: |
| 1054 | /* |
| 1055 | * If we did an incomplete transfer we must release |
| 1056 | * the pipe buffers in question: |
| 1057 | */ |
| 1058 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1059 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1060 | |
| 1061 | if (buf->ops) { |
| 1062 | buf->ops->release(pipe, buf); |
| 1063 | buf->ops = NULL; |
| 1064 | } |
| 1065 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1066 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1067 | if (!bytes) |
| 1068 | bytes = ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1069 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1070 | goto done; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1071 | } |
| 1072 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1073 | |
| 1074 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1075 | struct splice_desc *sd) |
| 1076 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1077 | struct file *file = sd->u.file; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1078 | |
| 1079 | return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); |
| 1080 | } |
| 1081 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1082 | /** |
| 1083 | * do_splice_direct - splices data directly between two files |
| 1084 | * @in: file to splice from |
| 1085 | * @ppos: input file offset |
| 1086 | * @out: file to splice to |
| 1087 | * @len: number of bytes to splice |
| 1088 | * @flags: splice modifier flags |
| 1089 | * |
| 1090 | * Description: |
| 1091 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1092 | * doing it in the application would incur an extra system call |
| 1093 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1094 | * can splice directly through a process-private pipe. |
| 1095 | * |
| 1096 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1097 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1098 | size_t len, unsigned int flags) |
| 1099 | { |
| 1100 | struct splice_desc sd = { |
| 1101 | .len = len, |
| 1102 | .total_len = len, |
| 1103 | .flags = flags, |
| 1104 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1105 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1106 | }; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1107 | long ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1108 | |
| 1109 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1110 | if (ret > 0) |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1111 | *ppos = sd.pos; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1112 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1113 | return ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1114 | } |
| 1115 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1116 | /* |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1117 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same |
| 1118 | * location, so checking ->i_pipe is not enough to verify that this is a |
| 1119 | * pipe. |
| 1120 | */ |
| 1121 | static inline struct pipe_inode_info *pipe_info(struct inode *inode) |
| 1122 | { |
| 1123 | if (S_ISFIFO(inode->i_mode)) |
| 1124 | return inode->i_pipe; |
| 1125 | |
| 1126 | return NULL; |
| 1127 | } |
| 1128 | |
| 1129 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1130 | * Determine where to splice to/from. |
| 1131 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1132 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1133 | struct file *out, loff_t __user *off_out, |
| 1134 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1135 | { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1136 | struct pipe_inode_info *pipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1137 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1138 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1139 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1140 | pipe = pipe_info(in->f_path.dentry->d_inode); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1141 | if (pipe) { |
| 1142 | if (off_in) |
| 1143 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1144 | if (off_out) { |
| 1145 | if (out->f_op->llseek == no_llseek) |
| 1146 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1147 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1148 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1149 | off = &offset; |
| 1150 | } else |
| 1151 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1152 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1153 | ret = do_splice_from(pipe, out, off, len, flags); |
| 1154 | |
| 1155 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1156 | ret = -EFAULT; |
| 1157 | |
| 1158 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1159 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1160 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1161 | pipe = pipe_info(out->f_path.dentry->d_inode); |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1162 | if (pipe) { |
| 1163 | if (off_out) |
| 1164 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1165 | if (off_in) { |
| 1166 | if (in->f_op->llseek == no_llseek) |
| 1167 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1168 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1169 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1170 | off = &offset; |
| 1171 | } else |
| 1172 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1173 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1174 | ret = do_splice_to(in, off, pipe, len, flags); |
| 1175 | |
| 1176 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1177 | ret = -EFAULT; |
| 1178 | |
| 1179 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1180 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1181 | |
| 1182 | return -EINVAL; |
| 1183 | } |
| 1184 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1185 | /* |
| 1186 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1187 | * partial_page structure, we can map several non-contiguous ranges into |
| 1188 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1189 | * Could easily be exported as a generic helper for other users, in which |
| 1190 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1191 | */ |
| 1192 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1193 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1194 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1195 | { |
| 1196 | int buffers = 0, error = 0; |
| 1197 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1198 | while (nr_vecs) { |
| 1199 | unsigned long off, npages; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1200 | struct iovec entry; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1201 | void __user *base; |
| 1202 | size_t len; |
| 1203 | int i; |
| 1204 | |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1205 | error = -EFAULT; |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1206 | if (copy_from_user(&entry, iov, sizeof(entry))) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1207 | break; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1208 | |
| 1209 | base = entry.iov_base; |
| 1210 | len = entry.iov_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1211 | |
| 1212 | /* |
| 1213 | * Sanity check this iovec. 0 read succeeds. |
| 1214 | */ |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1215 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1216 | if (unlikely(!len)) |
| 1217 | break; |
| 1218 | error = -EFAULT; |
Bastian Blank | 712a30e | 2008-02-10 16:47:57 +0200 | [diff] [blame] | 1219 | if (!access_ok(VERIFY_READ, base, len)) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1220 | break; |
| 1221 | |
| 1222 | /* |
| 1223 | * Get this base offset and number of pages, then map |
| 1224 | * in the user pages. |
| 1225 | */ |
| 1226 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1227 | |
| 1228 | /* |
| 1229 | * If asked for alignment, the offset must be zero and the |
| 1230 | * length a multiple of the PAGE_SIZE. |
| 1231 | */ |
| 1232 | error = -EINVAL; |
| 1233 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1234 | break; |
| 1235 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1236 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1237 | if (npages > PIPE_BUFFERS - buffers) |
| 1238 | npages = PIPE_BUFFERS - buffers; |
| 1239 | |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1240 | error = get_user_pages_fast((unsigned long)base, npages, |
| 1241 | 0, &pages[buffers]); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1242 | |
| 1243 | if (unlikely(error <= 0)) |
| 1244 | break; |
| 1245 | |
| 1246 | /* |
| 1247 | * Fill this contiguous range into the partial page map. |
| 1248 | */ |
| 1249 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1250 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1251 | |
| 1252 | partial[buffers].offset = off; |
| 1253 | partial[buffers].len = plen; |
| 1254 | |
| 1255 | off = 0; |
| 1256 | len -= plen; |
| 1257 | buffers++; |
| 1258 | } |
| 1259 | |
| 1260 | /* |
| 1261 | * We didn't complete this iov, stop here since it probably |
| 1262 | * means we have to move some of this into a pipe to |
| 1263 | * be able to continue. |
| 1264 | */ |
| 1265 | if (len) |
| 1266 | break; |
| 1267 | |
| 1268 | /* |
| 1269 | * Don't continue if we mapped fewer pages than we asked for, |
| 1270 | * or if we mapped the max number of pages that we have |
| 1271 | * room for. |
| 1272 | */ |
| 1273 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1274 | break; |
| 1275 | |
| 1276 | nr_vecs--; |
| 1277 | iov++; |
| 1278 | } |
| 1279 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1280 | if (buffers) |
| 1281 | return buffers; |
| 1282 | |
| 1283 | return error; |
| 1284 | } |
| 1285 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1286 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1287 | struct splice_desc *sd) |
| 1288 | { |
| 1289 | char *src; |
| 1290 | int ret; |
| 1291 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 1292 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1293 | if (unlikely(ret)) |
| 1294 | return ret; |
| 1295 | |
| 1296 | /* |
| 1297 | * See if we can use the atomic maps, by prefaulting in the |
| 1298 | * pages and doing an atomic copy |
| 1299 | */ |
| 1300 | if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { |
| 1301 | src = buf->ops->map(pipe, buf, 1); |
| 1302 | ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, |
| 1303 | sd->len); |
| 1304 | buf->ops->unmap(pipe, buf, src); |
| 1305 | if (!ret) { |
| 1306 | ret = sd->len; |
| 1307 | goto out; |
| 1308 | } |
| 1309 | } |
| 1310 | |
| 1311 | /* |
| 1312 | * No dice, use slow non-atomic map and copy |
| 1313 | */ |
| 1314 | src = buf->ops->map(pipe, buf, 0); |
| 1315 | |
| 1316 | ret = sd->len; |
| 1317 | if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) |
| 1318 | ret = -EFAULT; |
| 1319 | |
Jens Axboe | 6866bef | 2007-10-16 10:01:29 +0200 | [diff] [blame] | 1320 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1321 | out: |
| 1322 | if (ret > 0) |
| 1323 | sd->u.userptr += ret; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1324 | return ret; |
| 1325 | } |
| 1326 | |
| 1327 | /* |
| 1328 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1329 | * as a simple copy of the pipes pages to the user iov. |
| 1330 | */ |
| 1331 | static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, |
| 1332 | unsigned long nr_segs, unsigned int flags) |
| 1333 | { |
| 1334 | struct pipe_inode_info *pipe; |
| 1335 | struct splice_desc sd; |
| 1336 | ssize_t size; |
| 1337 | int error; |
| 1338 | long ret; |
| 1339 | |
| 1340 | pipe = pipe_info(file->f_path.dentry->d_inode); |
| 1341 | if (!pipe) |
| 1342 | return -EBADF; |
| 1343 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1344 | pipe_lock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1345 | |
| 1346 | error = ret = 0; |
| 1347 | while (nr_segs) { |
| 1348 | void __user *base; |
| 1349 | size_t len; |
| 1350 | |
| 1351 | /* |
| 1352 | * Get user address base and length for this iovec. |
| 1353 | */ |
| 1354 | error = get_user(base, &iov->iov_base); |
| 1355 | if (unlikely(error)) |
| 1356 | break; |
| 1357 | error = get_user(len, &iov->iov_len); |
| 1358 | if (unlikely(error)) |
| 1359 | break; |
| 1360 | |
| 1361 | /* |
| 1362 | * Sanity check this iovec. 0 read succeeds. |
| 1363 | */ |
| 1364 | if (unlikely(!len)) |
| 1365 | break; |
| 1366 | if (unlikely(!base)) { |
| 1367 | error = -EFAULT; |
| 1368 | break; |
| 1369 | } |
| 1370 | |
Jens Axboe | 8811930 | 2008-02-08 08:49:14 -0800 | [diff] [blame] | 1371 | if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { |
| 1372 | error = -EFAULT; |
| 1373 | break; |
| 1374 | } |
| 1375 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1376 | sd.len = 0; |
| 1377 | sd.total_len = len; |
| 1378 | sd.flags = flags; |
| 1379 | sd.u.userptr = base; |
| 1380 | sd.pos = 0; |
| 1381 | |
| 1382 | size = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1383 | if (size < 0) { |
| 1384 | if (!ret) |
| 1385 | ret = size; |
| 1386 | |
| 1387 | break; |
| 1388 | } |
| 1389 | |
| 1390 | ret += size; |
| 1391 | |
| 1392 | if (size < len) |
| 1393 | break; |
| 1394 | |
| 1395 | nr_segs--; |
| 1396 | iov++; |
| 1397 | } |
| 1398 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1399 | pipe_unlock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1400 | |
| 1401 | if (!ret) |
| 1402 | ret = error; |
| 1403 | |
| 1404 | return ret; |
| 1405 | } |
| 1406 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1407 | /* |
| 1408 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1409 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1410 | * to file). In both cases the output is a pipe, naturally. |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1411 | */ |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1412 | static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, |
| 1413 | unsigned long nr_segs, unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1414 | { |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1415 | struct pipe_inode_info *pipe; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1416 | struct page *pages[PIPE_BUFFERS]; |
| 1417 | struct partial_page partial[PIPE_BUFFERS]; |
| 1418 | struct splice_pipe_desc spd = { |
| 1419 | .pages = pages, |
| 1420 | .partial = partial, |
| 1421 | .flags = flags, |
| 1422 | .ops = &user_page_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 1423 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1424 | }; |
| 1425 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1426 | pipe = pipe_info(file->f_path.dentry->d_inode); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1427 | if (!pipe) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1428 | return -EBADF; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1429 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1430 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1431 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1432 | if (spd.nr_pages <= 0) |
| 1433 | return spd.nr_pages; |
| 1434 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1435 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1436 | } |
| 1437 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1438 | /* |
| 1439 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1440 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1441 | * operation that can be supported without any funky alignment restrictions |
| 1442 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1443 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1444 | * solutions for that: |
| 1445 | * |
| 1446 | * - memcpy() the data internally, at which point we might as well just |
| 1447 | * do a regular read() on the buffer anyway. |
| 1448 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1449 | * has restriction limitations on both ends of the pipe). |
| 1450 | * |
| 1451 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1452 | * |
| 1453 | */ |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1454 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, |
| 1455 | unsigned long, nr_segs, unsigned int, flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1456 | { |
| 1457 | struct file *file; |
| 1458 | long error; |
| 1459 | int fput; |
| 1460 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1461 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1462 | return -EINVAL; |
| 1463 | else if (unlikely(!nr_segs)) |
| 1464 | return 0; |
| 1465 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1466 | error = -EBADF; |
| 1467 | file = fget_light(fd, &fput); |
| 1468 | if (file) { |
| 1469 | if (file->f_mode & FMODE_WRITE) |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1470 | error = vmsplice_to_pipe(file, iov, nr_segs, flags); |
| 1471 | else if (file->f_mode & FMODE_READ) |
| 1472 | error = vmsplice_to_user(file, iov, nr_segs, flags); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1473 | |
| 1474 | fput_light(file, fput); |
| 1475 | } |
| 1476 | |
| 1477 | return error; |
| 1478 | } |
| 1479 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1480 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
| 1481 | int, fd_out, loff_t __user *, off_out, |
| 1482 | size_t, len, unsigned int, flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1483 | { |
| 1484 | long error; |
| 1485 | struct file *in, *out; |
| 1486 | int fput_in, fput_out; |
| 1487 | |
| 1488 | if (unlikely(!len)) |
| 1489 | return 0; |
| 1490 | |
| 1491 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1492 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1493 | if (in) { |
| 1494 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1495 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1496 | if (out) { |
| 1497 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1498 | error = do_splice(in, off_in, |
| 1499 | out, off_out, |
| 1500 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1501 | fput_light(out, fput_out); |
| 1502 | } |
| 1503 | } |
| 1504 | |
| 1505 | fput_light(in, fput_in); |
| 1506 | } |
| 1507 | |
| 1508 | return error; |
| 1509 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1510 | |
| 1511 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1512 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1513 | * return an appropriate error. |
| 1514 | */ |
| 1515 | static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1516 | { |
| 1517 | int ret; |
| 1518 | |
| 1519 | /* |
| 1520 | * Check ->nrbufs without the inode lock first. This function |
| 1521 | * is speculative anyways, so missing one is ok. |
| 1522 | */ |
| 1523 | if (pipe->nrbufs) |
| 1524 | return 0; |
| 1525 | |
| 1526 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1527 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1528 | |
| 1529 | while (!pipe->nrbufs) { |
| 1530 | if (signal_pending(current)) { |
| 1531 | ret = -ERESTARTSYS; |
| 1532 | break; |
| 1533 | } |
| 1534 | if (!pipe->writers) |
| 1535 | break; |
| 1536 | if (!pipe->waiting_writers) { |
| 1537 | if (flags & SPLICE_F_NONBLOCK) { |
| 1538 | ret = -EAGAIN; |
| 1539 | break; |
| 1540 | } |
| 1541 | } |
| 1542 | pipe_wait(pipe); |
| 1543 | } |
| 1544 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1545 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1546 | return ret; |
| 1547 | } |
| 1548 | |
| 1549 | /* |
| 1550 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1551 | * return an appropriate error. |
| 1552 | */ |
| 1553 | static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1554 | { |
| 1555 | int ret; |
| 1556 | |
| 1557 | /* |
| 1558 | * Check ->nrbufs without the inode lock first. This function |
| 1559 | * is speculative anyways, so missing one is ok. |
| 1560 | */ |
| 1561 | if (pipe->nrbufs < PIPE_BUFFERS) |
| 1562 | return 0; |
| 1563 | |
| 1564 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1565 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1566 | |
| 1567 | while (pipe->nrbufs >= PIPE_BUFFERS) { |
| 1568 | if (!pipe->readers) { |
| 1569 | send_sig(SIGPIPE, current, 0); |
| 1570 | ret = -EPIPE; |
| 1571 | break; |
| 1572 | } |
| 1573 | if (flags & SPLICE_F_NONBLOCK) { |
| 1574 | ret = -EAGAIN; |
| 1575 | break; |
| 1576 | } |
| 1577 | if (signal_pending(current)) { |
| 1578 | ret = -ERESTARTSYS; |
| 1579 | break; |
| 1580 | } |
| 1581 | pipe->waiting_writers++; |
| 1582 | pipe_wait(pipe); |
| 1583 | pipe->waiting_writers--; |
| 1584 | } |
| 1585 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1586 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1587 | return ret; |
| 1588 | } |
| 1589 | |
| 1590 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1591 | * Link contents of ipipe to opipe. |
| 1592 | */ |
| 1593 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1594 | struct pipe_inode_info *opipe, |
| 1595 | size_t len, unsigned int flags) |
| 1596 | { |
| 1597 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1598 | int ret = 0, i = 0, nbuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1599 | |
| 1600 | /* |
| 1601 | * Potential ABBA deadlock, work around it by ordering lock |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1602 | * grabbing by pipe info address. Otherwise two different processes |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1603 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1604 | */ |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1605 | pipe_double_lock(ipipe, opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1606 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1607 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1608 | if (!opipe->readers) { |
| 1609 | send_sig(SIGPIPE, current, 0); |
| 1610 | if (!ret) |
| 1611 | ret = -EPIPE; |
| 1612 | break; |
| 1613 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1614 | |
| 1615 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1616 | * If we have iterated all input buffers or ran out of |
| 1617 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1618 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1619 | if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1620 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1621 | |
| 1622 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1623 | nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1624 | |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1625 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1626 | * Get a reference to this pipe buffer, |
| 1627 | * so we can copy the contents over. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1628 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1629 | ibuf->ops->get(ipipe, ibuf); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1630 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1631 | obuf = opipe->bufs + nbuf; |
| 1632 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1633 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1634 | /* |
| 1635 | * Don't inherit the gift flag, we need to |
| 1636 | * prevent multiple steals of this page. |
| 1637 | */ |
| 1638 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1639 | |
| 1640 | if (obuf->len > len) |
| 1641 | obuf->len = len; |
| 1642 | |
| 1643 | opipe->nrbufs++; |
| 1644 | ret += obuf->len; |
| 1645 | len -= obuf->len; |
| 1646 | i++; |
| 1647 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1648 | |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1649 | /* |
| 1650 | * return EAGAIN if we have the potential of some data in the |
| 1651 | * future, otherwise just return 0 |
| 1652 | */ |
| 1653 | if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) |
| 1654 | ret = -EAGAIN; |
| 1655 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 1656 | pipe_unlock(ipipe); |
| 1657 | pipe_unlock(opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1658 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1659 | /* |
| 1660 | * If we put data in the output pipe, wakeup any potential readers. |
| 1661 | */ |
| 1662 | if (ret > 0) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1663 | smp_mb(); |
| 1664 | if (waitqueue_active(&opipe->wait)) |
| 1665 | wake_up_interruptible(&opipe->wait); |
| 1666 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1667 | } |
| 1668 | |
| 1669 | return ret; |
| 1670 | } |
| 1671 | |
| 1672 | /* |
| 1673 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1674 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1675 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1676 | * applicable one is SPLICE_F_NONBLOCK. |
| 1677 | */ |
| 1678 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1679 | unsigned int flags) |
| 1680 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1681 | struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1682 | 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] | 1683 | int ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1684 | |
| 1685 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1686 | * Duplicate the contents of ipipe to opipe without actually |
| 1687 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1688 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1689 | if (ipipe && opipe && ipipe != opipe) { |
| 1690 | /* |
| 1691 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1692 | * ordering doesn't really matter. |
| 1693 | */ |
| 1694 | ret = link_ipipe_prep(ipipe, flags); |
| 1695 | if (!ret) { |
| 1696 | ret = link_opipe_prep(opipe, flags); |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1697 | if (!ret) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1698 | ret = link_pipe(ipipe, opipe, len, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1699 | } |
| 1700 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1701 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1702 | return ret; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1703 | } |
| 1704 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1705 | SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1706 | { |
| 1707 | struct file *in; |
| 1708 | int error, fput_in; |
| 1709 | |
| 1710 | if (unlikely(!len)) |
| 1711 | return 0; |
| 1712 | |
| 1713 | error = -EBADF; |
| 1714 | in = fget_light(fdin, &fput_in); |
| 1715 | if (in) { |
| 1716 | if (in->f_mode & FMODE_READ) { |
| 1717 | int fput_out; |
| 1718 | struct file *out = fget_light(fdout, &fput_out); |
| 1719 | |
| 1720 | if (out) { |
| 1721 | if (out->f_mode & FMODE_WRITE) |
| 1722 | error = do_tee(in, out, len, flags); |
| 1723 | fput_light(out, fput_out); |
| 1724 | } |
| 1725 | } |
| 1726 | fput_light(in, fput_in); |
| 1727 | } |
| 1728 | |
| 1729 | return error; |
| 1730 | } |