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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame^] | 33 | #include <linux/gfp.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 34 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 35 | /* |
| 36 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 37 | * a vm helper function, it's already simplified quite a bit by the |
| 38 | * addition of remove_mapping(). If success is returned, the caller may |
| 39 | * attempt to reuse this page for another destination. |
| 40 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 41 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 42 | struct pipe_buffer *buf) |
| 43 | { |
| 44 | struct page *page = buf->page; |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 45 | struct address_space *mapping; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 46 | |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 47 | lock_page(page); |
| 48 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 49 | mapping = page_mapping(page); |
| 50 | if (mapping) { |
| 51 | WARN_ON(!PageUptodate(page)); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 52 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 53 | /* |
| 54 | * At least for ext2 with nobh option, we need to wait on |
| 55 | * writeback completing on this page, since we'll remove it |
| 56 | * from the pagecache. Otherwise truncate wont wait on the |
| 57 | * page, allowing the disk blocks to be reused by someone else |
| 58 | * before we actually wrote our data to them. fs corruption |
| 59 | * ensues. |
| 60 | */ |
| 61 | wait_on_page_writeback(page); |
Jens Axboe | ad8d6f0 | 2006-04-02 23:10:32 +0200 | [diff] [blame] | 62 | |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 63 | if (page_has_private(page) && |
| 64 | !try_to_release_page(page, GFP_KERNEL)) |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 65 | goto out_unlock; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 66 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 67 | /* |
| 68 | * If we succeeded in removing the mapping, set LRU flag |
| 69 | * and return good. |
| 70 | */ |
| 71 | if (remove_mapping(mapping, page)) { |
| 72 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 73 | return 0; |
| 74 | } |
Jens Axboe | 9e0267c | 2006-04-19 15:57:31 +0200 | [diff] [blame] | 75 | } |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 76 | |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 77 | /* |
| 78 | * Raced with truncate or failed to remove page from current |
| 79 | * address space, unlock and return failure. |
| 80 | */ |
Jens Axboe | ca39d65 | 2008-05-20 21:27:41 +0200 | [diff] [blame] | 81 | out_unlock: |
Jens Axboe | 9e94cd4 | 2006-06-20 15:01:12 +0200 | [diff] [blame] | 82 | unlock_page(page); |
| 83 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 84 | } |
| 85 | |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 86 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 87 | struct pipe_buffer *buf) |
| 88 | { |
| 89 | page_cache_release(buf->page); |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 90 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 91 | } |
| 92 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 93 | /* |
| 94 | * Check whether the contents of buf is OK to access. Since the content |
| 95 | * is a page cache page, IO may be in flight. |
| 96 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 97 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 98 | struct pipe_buffer *buf) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 99 | { |
| 100 | struct page *page = buf->page; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 101 | int err; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 102 | |
| 103 | if (!PageUptodate(page)) { |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 104 | lock_page(page); |
| 105 | |
| 106 | /* |
| 107 | * Page got truncated/unhashed. This will cause a 0-byte |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 108 | * splice, if this is the first page. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 109 | */ |
| 110 | if (!page->mapping) { |
| 111 | err = -ENODATA; |
| 112 | goto error; |
| 113 | } |
| 114 | |
| 115 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 116 | * Uh oh, read-error from disk. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 117 | */ |
| 118 | if (!PageUptodate(page)) { |
| 119 | err = -EIO; |
| 120 | goto error; |
| 121 | } |
| 122 | |
| 123 | /* |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 124 | * Page is ok afterall, we are done. |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 125 | */ |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 126 | unlock_page(page); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 127 | } |
| 128 | |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 129 | return 0; |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 130 | error: |
| 131 | unlock_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 132 | return err; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 133 | } |
| 134 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 135 | static const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 136 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 137 | .map = generic_pipe_buf_map, |
| 138 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 139 | .confirm = page_cache_pipe_buf_confirm, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 140 | .release = page_cache_pipe_buf_release, |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 141 | .steal = page_cache_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 142 | .get = generic_pipe_buf_get, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 143 | }; |
| 144 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 145 | static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 146 | struct pipe_buffer *buf) |
| 147 | { |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 148 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 149 | return 1; |
| 150 | |
Jens Axboe | 1432873 | 2006-05-03 10:35:26 +0200 | [diff] [blame] | 151 | buf->flags |= PIPE_BUF_FLAG_LRU; |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 152 | return generic_pipe_buf_steal(pipe, buf); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 153 | } |
| 154 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 155 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 156 | .can_merge = 0, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 157 | .map = generic_pipe_buf_map, |
| 158 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 159 | .confirm = generic_pipe_buf_confirm, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 160 | .release = page_cache_pipe_buf_release, |
| 161 | .steal = user_page_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 162 | .get = generic_pipe_buf_get, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 163 | }; |
| 164 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 165 | /** |
| 166 | * splice_to_pipe - fill passed data into a pipe |
| 167 | * @pipe: pipe to fill |
| 168 | * @spd: data to fill |
| 169 | * |
| 170 | * Description: |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 171 | * @spd contains a map of pages and len/offset tuples, along with |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 172 | * the struct pipe_buf_operations associated with these pages. This |
| 173 | * function will link that data to the pipe. |
| 174 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 175 | */ |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 176 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 177 | struct splice_pipe_desc *spd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 178 | { |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 179 | unsigned int spd_pages = spd->nr_pages; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 180 | int ret, do_wakeup, page_nr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 181 | |
| 182 | ret = 0; |
| 183 | do_wakeup = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 184 | page_nr = 0; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 185 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 186 | pipe_lock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 187 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 188 | for (;;) { |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 189 | if (!pipe->readers) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 190 | send_sig(SIGPIPE, current, 0); |
| 191 | if (!ret) |
| 192 | ret = -EPIPE; |
| 193 | break; |
| 194 | } |
| 195 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 196 | if (pipe->nrbufs < PIPE_BUFFERS) { |
| 197 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 198 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 199 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 200 | buf->page = spd->pages[page_nr]; |
| 201 | buf->offset = spd->partial[page_nr].offset; |
| 202 | buf->len = spd->partial[page_nr].len; |
Jens Axboe | 497f962 | 2007-06-11 12:00:45 +0200 | [diff] [blame] | 203 | buf->private = spd->partial[page_nr].private; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 204 | buf->ops = spd->ops; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 205 | if (spd->flags & SPLICE_F_GIFT) |
| 206 | buf->flags |= PIPE_BUF_FLAG_GIFT; |
| 207 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 208 | pipe->nrbufs++; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 209 | page_nr++; |
| 210 | ret += buf->len; |
| 211 | |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 212 | if (pipe->inode) |
| 213 | do_wakeup = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 214 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 215 | if (!--spd->nr_pages) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 216 | break; |
Jens Axboe | 6f767b0 | 2006-04-11 13:53:56 +0200 | [diff] [blame] | 217 | if (pipe->nrbufs < PIPE_BUFFERS) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 218 | continue; |
| 219 | |
| 220 | break; |
| 221 | } |
| 222 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 223 | if (spd->flags & SPLICE_F_NONBLOCK) { |
Linus Torvalds | 29e3509 | 2006-04-02 12:46:35 -0700 | [diff] [blame] | 224 | if (!ret) |
| 225 | ret = -EAGAIN; |
| 226 | break; |
| 227 | } |
| 228 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 229 | if (signal_pending(current)) { |
| 230 | if (!ret) |
| 231 | ret = -ERESTARTSYS; |
| 232 | break; |
| 233 | } |
| 234 | |
| 235 | if (do_wakeup) { |
Jens Axboe | c0bd1f6 | 2006-04-10 09:03:32 +0200 | [diff] [blame] | 236 | smp_mb(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 237 | if (waitqueue_active(&pipe->wait)) |
| 238 | wake_up_interruptible_sync(&pipe->wait); |
| 239 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 240 | do_wakeup = 0; |
| 241 | } |
| 242 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 243 | pipe->waiting_writers++; |
| 244 | pipe_wait(pipe); |
| 245 | pipe->waiting_writers--; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 246 | } |
| 247 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 248 | pipe_unlock(pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 249 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 250 | if (do_wakeup) { |
| 251 | smp_mb(); |
| 252 | if (waitqueue_active(&pipe->wait)) |
| 253 | wake_up_interruptible(&pipe->wait); |
| 254 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 255 | } |
| 256 | |
Jens Axboe | 00de00b | 2007-06-15 13:14:22 +0200 | [diff] [blame] | 257 | while (page_nr < spd_pages) |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 258 | spd->spd_release(spd, page_nr++); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 259 | |
| 260 | return ret; |
| 261 | } |
| 262 | |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 263 | static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) |
| 264 | { |
| 265 | page_cache_release(spd->pages[i]); |
| 266 | } |
| 267 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 268 | static int |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 269 | __generic_file_splice_read(struct file *in, loff_t *ppos, |
| 270 | struct pipe_inode_info *pipe, size_t len, |
| 271 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 272 | { |
| 273 | struct address_space *mapping = in->f_mapping; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 274 | unsigned int loff, nr_pages, req_pages; |
Jens Axboe | 16c523d | 2006-04-10 09:03:58 +0200 | [diff] [blame] | 275 | struct page *pages[PIPE_BUFFERS]; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 276 | struct partial_page partial[PIPE_BUFFERS]; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 277 | struct page *page; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 278 | pgoff_t index, end_index; |
| 279 | loff_t isize; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 280 | int error, page_nr; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 281 | struct splice_pipe_desc spd = { |
| 282 | .pages = pages, |
| 283 | .partial = partial, |
| 284 | .flags = flags, |
| 285 | .ops = &page_cache_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 286 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 287 | }; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 288 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 289 | index = *ppos >> PAGE_CACHE_SHIFT; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 290 | loff = *ppos & ~PAGE_CACHE_MASK; |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 291 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 292 | nr_pages = min(req_pages, (unsigned)PIPE_BUFFERS); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 293 | |
| 294 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 295 | * Lookup the (hopefully) full range of pages we need. |
| 296 | */ |
| 297 | spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 298 | index += spd.nr_pages; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 299 | |
| 300 | /* |
| 301 | * If find_get_pages_contig() returned fewer pages than we needed, |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 302 | * readahead/allocate the rest and fill in the holes. |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 303 | */ |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 304 | if (spd.nr_pages < nr_pages) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 305 | page_cache_sync_readahead(mapping, &in->f_ra, in, |
| 306 | index, req_pages - spd.nr_pages); |
Fengguang Wu | 431a482 | 2007-07-19 01:48:05 -0700 | [diff] [blame] | 307 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 308 | error = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 309 | while (spd.nr_pages < nr_pages) { |
| 310 | /* |
| 311 | * Page could be there, find_get_pages_contig() breaks on |
| 312 | * the first hole. |
| 313 | */ |
| 314 | page = find_get_page(mapping, index); |
| 315 | if (!page) { |
Jens Axboe | e27dedd | 2006-05-01 19:59:54 +0200 | [diff] [blame] | 316 | /* |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 317 | * page didn't exist, allocate one. |
| 318 | */ |
| 319 | page = page_cache_alloc_cold(mapping); |
| 320 | if (!page) |
| 321 | break; |
| 322 | |
| 323 | error = add_to_page_cache_lru(page, mapping, index, |
Hugh Dickins | 4cd1350 | 2008-04-03 23:35:22 +0100 | [diff] [blame] | 324 | mapping_gfp_mask(mapping)); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 325 | if (unlikely(error)) { |
| 326 | page_cache_release(page); |
Jens Axboe | a054887 | 2006-05-03 10:58:22 +0200 | [diff] [blame] | 327 | if (error == -EEXIST) |
| 328 | continue; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 329 | break; |
| 330 | } |
| 331 | /* |
| 332 | * add_to_page_cache() locks the page, unlock it |
| 333 | * to avoid convoluting the logic below even more. |
| 334 | */ |
| 335 | unlock_page(page); |
| 336 | } |
| 337 | |
| 338 | pages[spd.nr_pages++] = page; |
| 339 | index++; |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Now loop over the map and see if we need to start IO on any |
| 344 | * pages, fill in the partial map, etc. |
| 345 | */ |
| 346 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 347 | nr_pages = spd.nr_pages; |
| 348 | spd.nr_pages = 0; |
| 349 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 350 | unsigned int this_len; |
| 351 | |
| 352 | if (!len) |
| 353 | break; |
| 354 | |
| 355 | /* |
| 356 | * this_len is the max we'll use from this page |
| 357 | */ |
Andrew Morton | ba5f5d9 | 2006-04-25 15:33:34 +0200 | [diff] [blame] | 358 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 359 | page = pages[page_nr]; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 360 | |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 361 | if (PageReadahead(page)) |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 362 | page_cache_async_readahead(mapping, &in->f_ra, in, |
Fengguang Wu | d898391 | 2007-07-19 01:48:06 -0700 | [diff] [blame] | 363 | page, index, req_pages - page_nr); |
Fengguang Wu | a08a166 | 2007-07-19 01:48:03 -0700 | [diff] [blame] | 364 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 365 | /* |
| 366 | * If the page isn't uptodate, we may need to start io on it |
| 367 | */ |
| 368 | if (!PageUptodate(page)) { |
Jens Axboe | c4f895c | 2006-04-19 15:56:12 +0200 | [diff] [blame] | 369 | /* |
| 370 | * If in nonblock mode then dont block on waiting |
| 371 | * for an in-flight io page |
| 372 | */ |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 373 | if (flags & SPLICE_F_NONBLOCK) { |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 374 | if (!trylock_page(page)) { |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 375 | error = -EAGAIN; |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 376 | break; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 377 | } |
Fengguang Wu | 9ae9d68 | 2007-05-08 08:44:36 +0200 | [diff] [blame] | 378 | } else |
| 379 | lock_page(page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 380 | |
| 381 | /* |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 382 | * Page was truncated, or invalidated by the |
| 383 | * filesystem. Redo the find/create, but this time the |
| 384 | * page is kept locked, so there's no chance of another |
| 385 | * race with truncate/invalidate. |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 386 | */ |
| 387 | if (!page->mapping) { |
| 388 | unlock_page(page); |
Miklos Szeredi | 32502b8 | 2008-07-04 09:35:17 +0200 | [diff] [blame] | 389 | page = find_or_create_page(mapping, index, |
| 390 | mapping_gfp_mask(mapping)); |
| 391 | |
| 392 | if (!page) { |
| 393 | error = -ENOMEM; |
| 394 | break; |
| 395 | } |
| 396 | page_cache_release(pages[page_nr]); |
| 397 | pages[page_nr] = page; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 398 | } |
| 399 | /* |
| 400 | * page was already under io and is now done, great |
| 401 | */ |
| 402 | if (PageUptodate(page)) { |
| 403 | unlock_page(page); |
| 404 | goto fill_it; |
| 405 | } |
| 406 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 407 | /* |
| 408 | * need to read in the page |
| 409 | */ |
| 410 | error = mapping->a_ops->readpage(in, page); |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 411 | if (unlikely(error)) { |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 412 | /* |
| 413 | * We really should re-lookup the page here, |
| 414 | * but it complicates things a lot. Instead |
| 415 | * lets just do what we already stored, and |
| 416 | * we'll get it the next time we are called. |
| 417 | */ |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 418 | if (error == AOP_TRUNCATED_PAGE) |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 419 | error = 0; |
| 420 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 421 | break; |
| 422 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 423 | } |
| 424 | fill_it: |
| 425 | /* |
| 426 | * i_size must be checked after PageUptodate. |
| 427 | */ |
| 428 | isize = i_size_read(mapping->host); |
| 429 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 430 | if (unlikely(!isize || index > end_index)) |
| 431 | break; |
| 432 | |
| 433 | /* |
| 434 | * if this is the last page, see if we need to shrink |
| 435 | * the length and stop |
| 436 | */ |
| 437 | if (end_index == index) { |
| 438 | unsigned int plen; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 439 | |
| 440 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 441 | * max good bytes in this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 442 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 443 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 444 | if (plen <= loff) |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 445 | break; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 446 | |
| 447 | /* |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 448 | * force quit after adding this page |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 449 | */ |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 450 | this_len = min(this_len, plen - loff); |
| 451 | len = this_len; |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 452 | } |
Jens Axboe | 620a324 | 2007-06-07 09:39:42 +0200 | [diff] [blame] | 453 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 454 | partial[page_nr].offset = loff; |
| 455 | partial[page_nr].len = this_len; |
Jens Axboe | 82aa5d6 | 2006-04-20 13:05:48 +0200 | [diff] [blame] | 456 | len -= this_len; |
Jens Axboe | 91ad66e | 2006-04-19 15:55:10 +0200 | [diff] [blame] | 457 | loff = 0; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 458 | spd.nr_pages++; |
| 459 | index++; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 460 | } |
| 461 | |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 462 | /* |
Hugh Dickins | 475ecad | 2007-06-07 09:36:00 +0200 | [diff] [blame] | 463 | * 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] | 464 | * we got, 'nr_pages' is how many pages are in the map. |
| 465 | */ |
| 466 | while (page_nr < nr_pages) |
| 467 | page_cache_release(pages[page_nr++]); |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 468 | in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; |
Jens Axboe | eb20796 | 2006-04-27 11:05:22 +0200 | [diff] [blame] | 469 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 470 | if (spd.nr_pages) |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 471 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 472 | |
Jens Axboe | 7480a90 | 2006-04-11 13:52:47 +0200 | [diff] [blame] | 473 | return error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 474 | } |
| 475 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 476 | /** |
| 477 | * generic_file_splice_read - splice data from file to a pipe |
| 478 | * @in: file to splice from |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 479 | * @ppos: position in @in |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 480 | * @pipe: pipe to splice to |
| 481 | * @len: number of bytes to splice |
| 482 | * @flags: splice modifier flags |
| 483 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 484 | * Description: |
| 485 | * Will read pages from given file and fill them into a pipe. Can be |
| 486 | * used as long as the address_space operations for the source implements |
| 487 | * a readpage() hook. |
| 488 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 489 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 490 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 491 | struct pipe_inode_info *pipe, size_t len, |
| 492 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 493 | { |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 494 | loff_t isize, left; |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 495 | int ret; |
Jens Axboe | d366d398 | 2007-06-01 14:54:11 +0200 | [diff] [blame] | 496 | |
| 497 | isize = i_size_read(in->f_mapping->host); |
| 498 | if (unlikely(*ppos >= isize)) |
| 499 | return 0; |
| 500 | |
| 501 | left = isize - *ppos; |
| 502 | if (unlikely(left < len)) |
| 503 | len = left; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 504 | |
Jens Axboe | 8191ecd | 2008-04-10 08:24:25 +0200 | [diff] [blame] | 505 | ret = __generic_file_splice_read(in, ppos, pipe, len, flags); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame] | 506 | if (ret > 0) { |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 507 | *ppos += ret; |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame] | 508 | file_accessed(in); |
| 509 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 510 | |
| 511 | return ret; |
| 512 | } |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 513 | EXPORT_SYMBOL(generic_file_splice_read); |
| 514 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 515 | static const struct pipe_buf_operations default_pipe_buf_ops = { |
| 516 | .can_merge = 0, |
| 517 | .map = generic_pipe_buf_map, |
| 518 | .unmap = generic_pipe_buf_unmap, |
| 519 | .confirm = generic_pipe_buf_confirm, |
| 520 | .release = generic_pipe_buf_release, |
| 521 | .steal = generic_pipe_buf_steal, |
| 522 | .get = generic_pipe_buf_get, |
| 523 | }; |
| 524 | |
| 525 | static ssize_t kernel_readv(struct file *file, const struct iovec *vec, |
| 526 | unsigned long vlen, loff_t offset) |
| 527 | { |
| 528 | mm_segment_t old_fs; |
| 529 | loff_t pos = offset; |
| 530 | ssize_t res; |
| 531 | |
| 532 | old_fs = get_fs(); |
| 533 | set_fs(get_ds()); |
| 534 | /* The cast to a user pointer is valid due to the set_fs() */ |
| 535 | res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos); |
| 536 | set_fs(old_fs); |
| 537 | |
| 538 | return res; |
| 539 | } |
| 540 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 541 | static ssize_t kernel_write(struct file *file, const char *buf, size_t count, |
| 542 | loff_t pos) |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 543 | { |
| 544 | mm_segment_t old_fs; |
| 545 | ssize_t res; |
| 546 | |
| 547 | old_fs = get_fs(); |
| 548 | set_fs(get_ds()); |
| 549 | /* The cast to a user pointer is valid due to the set_fs() */ |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 550 | res = vfs_write(file, (const char __user *)buf, count, &pos); |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 551 | set_fs(old_fs); |
| 552 | |
| 553 | return res; |
| 554 | } |
| 555 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 556 | ssize_t default_file_splice_read(struct file *in, loff_t *ppos, |
| 557 | struct pipe_inode_info *pipe, size_t len, |
| 558 | unsigned int flags) |
| 559 | { |
| 560 | unsigned int nr_pages; |
| 561 | unsigned int nr_freed; |
| 562 | size_t offset; |
| 563 | struct page *pages[PIPE_BUFFERS]; |
| 564 | struct partial_page partial[PIPE_BUFFERS]; |
| 565 | struct iovec vec[PIPE_BUFFERS]; |
| 566 | pgoff_t index; |
| 567 | ssize_t res; |
| 568 | size_t this_len; |
| 569 | int error; |
| 570 | int i; |
| 571 | struct splice_pipe_desc spd = { |
| 572 | .pages = pages, |
| 573 | .partial = partial, |
| 574 | .flags = flags, |
| 575 | .ops = &default_pipe_buf_ops, |
| 576 | .spd_release = spd_release_page, |
| 577 | }; |
| 578 | |
| 579 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 580 | offset = *ppos & ~PAGE_CACHE_MASK; |
| 581 | nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 582 | |
| 583 | for (i = 0; i < nr_pages && i < PIPE_BUFFERS && len; i++) { |
| 584 | struct page *page; |
| 585 | |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 586 | page = alloc_page(GFP_USER); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 587 | error = -ENOMEM; |
| 588 | if (!page) |
| 589 | goto err; |
| 590 | |
| 591 | this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset); |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 592 | vec[i].iov_base = (void __user *) page_address(page); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 593 | vec[i].iov_len = this_len; |
| 594 | pages[i] = page; |
| 595 | spd.nr_pages++; |
| 596 | len -= this_len; |
| 597 | offset = 0; |
| 598 | } |
| 599 | |
| 600 | res = kernel_readv(in, vec, spd.nr_pages, *ppos); |
Andrew Morton | 77f6bf5 | 2009-05-14 09:49:44 +0200 | [diff] [blame] | 601 | if (res < 0) { |
| 602 | error = res; |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 603 | goto err; |
Andrew Morton | 77f6bf5 | 2009-05-14 09:49:44 +0200 | [diff] [blame] | 604 | } |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 605 | |
| 606 | error = 0; |
| 607 | if (!res) |
| 608 | goto err; |
| 609 | |
| 610 | nr_freed = 0; |
| 611 | for (i = 0; i < spd.nr_pages; i++) { |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 612 | this_len = min_t(size_t, vec[i].iov_len, res); |
| 613 | partial[i].offset = 0; |
| 614 | partial[i].len = this_len; |
| 615 | if (!this_len) { |
| 616 | __free_page(pages[i]); |
| 617 | pages[i] = NULL; |
| 618 | nr_freed++; |
| 619 | } |
| 620 | res -= this_len; |
| 621 | } |
| 622 | spd.nr_pages -= nr_freed; |
| 623 | |
| 624 | res = splice_to_pipe(pipe, &spd); |
| 625 | if (res > 0) |
| 626 | *ppos += res; |
| 627 | |
| 628 | return res; |
| 629 | |
| 630 | err: |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 631 | for (i = 0; i < spd.nr_pages; i++) |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 632 | __free_page(pages[i]); |
Jens Axboe | 4f23122 | 2009-05-13 08:35:35 +0200 | [diff] [blame] | 633 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 634 | return error; |
| 635 | } |
| 636 | EXPORT_SYMBOL(default_file_splice_read); |
| 637 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 638 | /* |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 639 | * 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] | 640 | * using sendpage(). Return the number of bytes sent. |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 641 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 642 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 643 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 644 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 645 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 646 | loff_t pos = sd->pos; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 647 | int ret, more; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 648 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 649 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 650 | if (!ret) { |
| 651 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
Changli Gao | cc56f7d | 2009-11-04 09:09:52 +0100 | [diff] [blame] | 652 | if (file->f_op && file->f_op->sendpage) |
| 653 | ret = file->f_op->sendpage(file, buf->page, buf->offset, |
| 654 | sd->len, &pos, more); |
| 655 | else |
| 656 | ret = -EINVAL; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 657 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 658 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 659 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 660 | } |
| 661 | |
| 662 | /* |
| 663 | * This is a little more tricky than the file -> pipe splicing. There are |
| 664 | * basically three cases: |
| 665 | * |
| 666 | * - Destination page already exists in the address space and there |
| 667 | * are users of it. For that case we have no other option that |
| 668 | * copying the data. Tough luck. |
| 669 | * - Destination page already exists in the address space, but there |
| 670 | * are no users of it. Make sure it's uptodate, then drop it. Fall |
| 671 | * through to last case. |
| 672 | * - Destination page does not exist, we can add the pipe page to |
| 673 | * the page cache and avoid the copy. |
| 674 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 675 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
| 676 | * sd->flags), we attempt to migrate pages from the pipe to the output |
| 677 | * file address space page cache. This is possible if no one else has |
| 678 | * the pipe page referenced outside of the pipe and page cache. If |
| 679 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create |
| 680 | * 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] | 681 | */ |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 682 | int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 683 | struct splice_desc *sd) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 684 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 685 | struct file *file = sd->u.file; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 686 | struct address_space *mapping = file->f_mapping; |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 687 | unsigned int offset, this_len; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 688 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 689 | void *fsdata; |
Jens Axboe | 3e7ee3e | 2006-04-02 23:11:04 +0200 | [diff] [blame] | 690 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 691 | |
| 692 | /* |
Jens Axboe | 49d0b21 | 2006-04-10 09:04:41 +0200 | [diff] [blame] | 693 | * make sure the data in this buffer is uptodate |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 694 | */ |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 695 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 696 | if (unlikely(ret)) |
| 697 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 698 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 699 | offset = sd->pos & ~PAGE_CACHE_MASK; |
| 700 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 701 | this_len = sd->len; |
| 702 | if (this_len + offset > PAGE_CACHE_SIZE) |
| 703 | this_len = PAGE_CACHE_SIZE - offset; |
| 704 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 705 | ret = pagecache_write_begin(file, mapping, sd->pos, this_len, |
| 706 | AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); |
| 707 | if (unlikely(ret)) |
| 708 | goto out; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 709 | |
Jens Axboe | 0568b40 | 2006-05-01 19:50:48 +0200 | [diff] [blame] | 710 | if (buf->page != page) { |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 711 | /* |
| 712 | * Careful, ->map() uses KM_USER0! |
| 713 | */ |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 714 | char *src = buf->ops->map(pipe, buf, 1); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 715 | char *dst = kmap_atomic(page, KM_USER1); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 716 | |
Jens Axboe | 016b661 | 2006-04-25 15:42:00 +0200 | [diff] [blame] | 717 | memcpy(dst + offset, src + buf->offset, this_len); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 718 | flush_dcache_page(page); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 719 | kunmap_atomic(dst, KM_USER1); |
Jens Axboe | 76ad4d1 | 2006-05-03 10:41:33 +0200 | [diff] [blame] | 720 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 721 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 722 | ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, |
| 723 | page, fsdata); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 724 | out: |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 725 | return ret; |
| 726 | } |
Miklos Szeredi | 328eaab | 2009-04-14 19:48:39 +0200 | [diff] [blame] | 727 | EXPORT_SYMBOL(pipe_to_file); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 728 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 729 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
| 730 | { |
| 731 | smp_mb(); |
| 732 | if (waitqueue_active(&pipe->wait)) |
| 733 | wake_up_interruptible(&pipe->wait); |
| 734 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
| 735 | } |
| 736 | |
| 737 | /** |
| 738 | * splice_from_pipe_feed - feed available data from a pipe to a file |
| 739 | * @pipe: pipe to splice from |
| 740 | * @sd: information to @actor |
| 741 | * @actor: handler that splices the data |
| 742 | * |
| 743 | * Description: |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 744 | * This function loops over the pipe and calls @actor to do the |
| 745 | * actual moving of a single struct pipe_buffer to the desired |
| 746 | * destination. It returns when there's no more buffers left in |
| 747 | * the pipe or if the requested number of bytes (@sd->total_len) |
| 748 | * have been copied. It returns a positive number (one) if the |
| 749 | * pipe needs to be filled with more data, zero if the required |
| 750 | * number of bytes have been copied and -errno on error. |
| 751 | * |
| 752 | * This, together with splice_from_pipe_{begin,end,next}, may be |
| 753 | * used to implement the functionality of __splice_from_pipe() when |
| 754 | * locking is required around copying the pipe buffers to the |
| 755 | * destination. |
| 756 | */ |
| 757 | int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 758 | splice_actor *actor) |
| 759 | { |
| 760 | int ret; |
| 761 | |
| 762 | while (pipe->nrbufs) { |
| 763 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; |
| 764 | const struct pipe_buf_operations *ops = buf->ops; |
| 765 | |
| 766 | sd->len = buf->len; |
| 767 | if (sd->len > sd->total_len) |
| 768 | sd->len = sd->total_len; |
| 769 | |
| 770 | ret = actor(pipe, buf, sd); |
| 771 | if (ret <= 0) { |
| 772 | if (ret == -ENODATA) |
| 773 | ret = 0; |
| 774 | return ret; |
| 775 | } |
| 776 | buf->offset += ret; |
| 777 | buf->len -= ret; |
| 778 | |
| 779 | sd->num_spliced += ret; |
| 780 | sd->len -= ret; |
| 781 | sd->pos += ret; |
| 782 | sd->total_len -= ret; |
| 783 | |
| 784 | if (!buf->len) { |
| 785 | buf->ops = NULL; |
| 786 | ops->release(pipe, buf); |
| 787 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
| 788 | pipe->nrbufs--; |
| 789 | if (pipe->inode) |
| 790 | sd->need_wakeup = true; |
| 791 | } |
| 792 | |
| 793 | if (!sd->total_len) |
| 794 | return 0; |
| 795 | } |
| 796 | |
| 797 | return 1; |
| 798 | } |
| 799 | EXPORT_SYMBOL(splice_from_pipe_feed); |
| 800 | |
| 801 | /** |
| 802 | * splice_from_pipe_next - wait for some data to splice from |
| 803 | * @pipe: pipe to splice from |
| 804 | * @sd: information about the splice operation |
| 805 | * |
| 806 | * Description: |
| 807 | * This function will wait for some data and return a positive |
| 808 | * value (one) if pipe buffers are available. It will return zero |
| 809 | * or -errno if no more data needs to be spliced. |
| 810 | */ |
| 811 | int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 812 | { |
| 813 | while (!pipe->nrbufs) { |
| 814 | if (!pipe->writers) |
| 815 | return 0; |
| 816 | |
| 817 | if (!pipe->waiting_writers && sd->num_spliced) |
| 818 | return 0; |
| 819 | |
| 820 | if (sd->flags & SPLICE_F_NONBLOCK) |
| 821 | return -EAGAIN; |
| 822 | |
| 823 | if (signal_pending(current)) |
| 824 | return -ERESTARTSYS; |
| 825 | |
| 826 | if (sd->need_wakeup) { |
| 827 | wakeup_pipe_writers(pipe); |
| 828 | sd->need_wakeup = false; |
| 829 | } |
| 830 | |
| 831 | pipe_wait(pipe); |
| 832 | } |
| 833 | |
| 834 | return 1; |
| 835 | } |
| 836 | EXPORT_SYMBOL(splice_from_pipe_next); |
| 837 | |
| 838 | /** |
| 839 | * splice_from_pipe_begin - start splicing from pipe |
Randy Dunlap | b80901b | 2009-04-16 19:09:55 -0700 | [diff] [blame] | 840 | * @sd: information about the splice operation |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 841 | * |
| 842 | * Description: |
| 843 | * This function should be called before a loop containing |
| 844 | * splice_from_pipe_next() and splice_from_pipe_feed() to |
| 845 | * initialize the necessary fields of @sd. |
| 846 | */ |
| 847 | void splice_from_pipe_begin(struct splice_desc *sd) |
| 848 | { |
| 849 | sd->num_spliced = 0; |
| 850 | sd->need_wakeup = false; |
| 851 | } |
| 852 | EXPORT_SYMBOL(splice_from_pipe_begin); |
| 853 | |
| 854 | /** |
| 855 | * splice_from_pipe_end - finish splicing from pipe |
| 856 | * @pipe: pipe to splice from |
| 857 | * @sd: information about the splice operation |
| 858 | * |
| 859 | * Description: |
| 860 | * This function will wake up pipe writers if necessary. It should |
| 861 | * be called after a loop containing splice_from_pipe_next() and |
| 862 | * splice_from_pipe_feed(). |
| 863 | */ |
| 864 | void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 865 | { |
| 866 | if (sd->need_wakeup) |
| 867 | wakeup_pipe_writers(pipe); |
| 868 | } |
| 869 | EXPORT_SYMBOL(splice_from_pipe_end); |
| 870 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 871 | /** |
| 872 | * __splice_from_pipe - splice data from a pipe to given actor |
| 873 | * @pipe: pipe to splice from |
| 874 | * @sd: information to @actor |
| 875 | * @actor: handler that splices the data |
| 876 | * |
| 877 | * Description: |
| 878 | * This function does little more than loop over the pipe and call |
| 879 | * @actor to do the actual moving of a single struct pipe_buffer to |
| 880 | * the desired destination. See pipe_to_file, pipe_to_sendpage, or |
| 881 | * pipe_to_user. |
| 882 | * |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 883 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 884 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 885 | splice_actor *actor) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 886 | { |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 887 | int ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 888 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 889 | splice_from_pipe_begin(sd); |
| 890 | do { |
| 891 | ret = splice_from_pipe_next(pipe, sd); |
| 892 | if (ret > 0) |
| 893 | ret = splice_from_pipe_feed(pipe, sd, actor); |
| 894 | } while (ret > 0); |
| 895 | splice_from_pipe_end(pipe, sd); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 896 | |
Miklos Szeredi | b3c2d2d | 2009-04-14 19:48:36 +0200 | [diff] [blame] | 897 | return sd->num_spliced ? sd->num_spliced : ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 898 | } |
Mark Fasheh | 40bee44 | 2007-03-21 13:11:02 +0100 | [diff] [blame] | 899 | EXPORT_SYMBOL(__splice_from_pipe); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 900 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 901 | /** |
| 902 | * splice_from_pipe - splice data from a pipe to a file |
| 903 | * @pipe: pipe to splice from |
| 904 | * @out: file to splice to |
| 905 | * @ppos: position in @out |
| 906 | * @len: how many bytes to splice |
| 907 | * @flags: splice modifier flags |
| 908 | * @actor: handler that splices the data |
| 909 | * |
| 910 | * Description: |
Miklos Szeredi | 2933970 | 2009-04-14 19:48:37 +0200 | [diff] [blame] | 911 | * See __splice_from_pipe. This function locks the pipe inode, |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 912 | * otherwise it's identical to __splice_from_pipe(). |
| 913 | * |
| 914 | */ |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 915 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 916 | loff_t *ppos, size_t len, unsigned int flags, |
| 917 | splice_actor *actor) |
| 918 | { |
| 919 | ssize_t ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 920 | struct splice_desc sd = { |
| 921 | .total_len = len, |
| 922 | .flags = flags, |
| 923 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 924 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 925 | }; |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 926 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 927 | pipe_lock(pipe); |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 928 | ret = __splice_from_pipe(pipe, &sd, actor); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 929 | pipe_unlock(pipe); |
Mark Fasheh | 6da6180 | 2006-10-17 18:43:07 +0200 | [diff] [blame] | 930 | |
| 931 | return ret; |
| 932 | } |
| 933 | |
| 934 | /** |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 935 | * generic_file_splice_write - splice data from a pipe to a file |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 936 | * @pipe: pipe info |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 937 | * @out: file to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 938 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 939 | * @len: number of bytes to splice |
| 940 | * @flags: splice modifier flags |
| 941 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 942 | * Description: |
| 943 | * Will either move or copy pages (determined by @flags options) from |
| 944 | * the given pipe inode to the given file. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 945 | * |
| 946 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 947 | ssize_t |
| 948 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 949 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 950 | { |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 951 | struct address_space *mapping = out->f_mapping; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 952 | struct inode *inode = mapping->host; |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 953 | struct splice_desc sd = { |
| 954 | .total_len = len, |
| 955 | .flags = flags, |
| 956 | .pos = *ppos, |
| 957 | .u.file = out, |
| 958 | }; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 959 | ssize_t ret; |
Jens Axboe | 8c34e2d | 2006-10-17 19:43:22 +0200 | [diff] [blame] | 960 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 961 | pipe_lock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 962 | |
| 963 | splice_from_pipe_begin(&sd); |
| 964 | do { |
| 965 | ret = splice_from_pipe_next(pipe, &sd); |
| 966 | if (ret <= 0) |
| 967 | break; |
| 968 | |
| 969 | mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); |
| 970 | ret = file_remove_suid(out); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame] | 971 | if (!ret) { |
| 972 | file_update_time(out); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 973 | ret = splice_from_pipe_feed(pipe, &sd, pipe_to_file); |
Miklos Szeredi | 723590e | 2009-08-15 08:43:22 +0200 | [diff] [blame] | 974 | } |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 975 | mutex_unlock(&inode->i_mutex); |
| 976 | } while (ret > 0); |
| 977 | splice_from_pipe_end(pipe, &sd); |
| 978 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 979 | pipe_unlock(pipe); |
Miklos Szeredi | eb443e5 | 2009-04-14 19:48:38 +0200 | [diff] [blame] | 980 | |
| 981 | if (sd.num_spliced) |
| 982 | ret = sd.num_spliced; |
| 983 | |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 984 | if (ret > 0) { |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 985 | unsigned long nr_pages; |
Jan Kara | 148f948 | 2009-08-17 19:52:36 +0200 | [diff] [blame] | 986 | int err; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 987 | |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 988 | nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 989 | |
Jan Kara | 148f948 | 2009-08-17 19:52:36 +0200 | [diff] [blame] | 990 | err = generic_write_sync(out, *ppos, ret); |
| 991 | if (err) |
| 992 | ret = err; |
| 993 | else |
| 994 | *ppos += ret; |
Jens Axboe | 17ee4f4 | 2007-06-15 13:10:37 +0200 | [diff] [blame] | 995 | balance_dirty_pages_ratelimited_nr(mapping, nr_pages); |
Jens Axboe | 4f6f0bd | 2006-04-02 23:04:46 +0200 | [diff] [blame] | 996 | } |
| 997 | |
| 998 | return ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 999 | } |
| 1000 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 1001 | EXPORT_SYMBOL(generic_file_splice_write); |
| 1002 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1003 | static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1004 | struct splice_desc *sd) |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1005 | { |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1006 | int ret; |
| 1007 | void *data; |
| 1008 | |
| 1009 | ret = buf->ops->confirm(pipe, buf); |
| 1010 | if (ret) |
| 1011 | return ret; |
| 1012 | |
| 1013 | data = buf->ops->map(pipe, buf, 0); |
| 1014 | ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos); |
| 1015 | buf->ops->unmap(pipe, buf, data); |
| 1016 | |
| 1017 | return ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1018 | } |
| 1019 | |
| 1020 | static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, |
| 1021 | struct file *out, loff_t *ppos, |
| 1022 | size_t len, unsigned int flags) |
| 1023 | { |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1024 | ssize_t ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1025 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1026 | ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); |
| 1027 | if (ret > 0) |
| 1028 | *ppos += ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1029 | |
Miklos Szeredi | b2858d7 | 2009-05-19 11:37:46 +0200 | [diff] [blame] | 1030 | return ret; |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1031 | } |
| 1032 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1033 | /** |
| 1034 | * generic_splice_sendpage - splice data from a pipe to a socket |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1035 | * @pipe: pipe to splice from |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1036 | * @out: socket to write to |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1037 | * @ppos: position in @out |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1038 | * @len: number of bytes to splice |
| 1039 | * @flags: splice modifier flags |
| 1040 | * |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1041 | * Description: |
| 1042 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 1043 | * is involved. |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1044 | * |
| 1045 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1046 | 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] | 1047 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1048 | { |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1049 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1050 | } |
| 1051 | |
Jens Axboe | 059a8f3 | 2006-04-02 23:06:05 +0200 | [diff] [blame] | 1052 | EXPORT_SYMBOL(generic_splice_sendpage); |
Jeff Garzik | a0f0678 | 2006-03-30 23:06:13 -0500 | [diff] [blame] | 1053 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1054 | /* |
| 1055 | * Attempt to initiate a splice from pipe to file. |
| 1056 | */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 1057 | 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] | 1058 | loff_t *ppos, size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1059 | { |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1060 | ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, |
| 1061 | loff_t *, size_t, unsigned int); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1062 | int ret; |
| 1063 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1064 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1065 | return -EBADF; |
| 1066 | |
Linus Torvalds | efc968d | 2008-10-09 14:04:54 -0700 | [diff] [blame] | 1067 | if (unlikely(out->f_flags & O_APPEND)) |
| 1068 | return -EINVAL; |
| 1069 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1070 | ret = rw_verify_area(WRITE, out, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1071 | if (unlikely(ret < 0)) |
| 1072 | return ret; |
| 1073 | |
Changli Gao | cc56f7d | 2009-11-04 09:09:52 +0100 | [diff] [blame] | 1074 | if (out->f_op && out->f_op->splice_write) |
| 1075 | splice_write = out->f_op->splice_write; |
| 1076 | else |
Miklos Szeredi | 0b0a47f | 2009-05-07 15:37:37 +0200 | [diff] [blame] | 1077 | splice_write = default_file_splice_write; |
| 1078 | |
| 1079 | return splice_write(pipe, out, ppos, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1080 | } |
| 1081 | |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1082 | /* |
| 1083 | * Attempt to initiate a splice from a file to a pipe. |
| 1084 | */ |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1085 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 1086 | struct pipe_inode_info *pipe, size_t len, |
| 1087 | unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1088 | { |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 1089 | ssize_t (*splice_read)(struct file *, loff_t *, |
| 1090 | struct pipe_inode_info *, size_t, unsigned int); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1091 | int ret; |
| 1092 | |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1093 | if (unlikely(!(in->f_mode & FMODE_READ))) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1094 | return -EBADF; |
| 1095 | |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1096 | ret = rw_verify_area(READ, in, ppos, len); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1097 | if (unlikely(ret < 0)) |
| 1098 | return ret; |
| 1099 | |
Changli Gao | cc56f7d | 2009-11-04 09:09:52 +0100 | [diff] [blame] | 1100 | if (in->f_op && in->f_op->splice_read) |
| 1101 | splice_read = in->f_op->splice_read; |
| 1102 | else |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 1103 | splice_read = default_file_splice_read; |
| 1104 | |
| 1105 | return splice_read(in, ppos, pipe, len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1106 | } |
| 1107 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1108 | /** |
| 1109 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 1110 | * @in: file to splice from |
| 1111 | * @sd: actor information on where to splice to |
| 1112 | * @actor: handles the data splicing |
| 1113 | * |
| 1114 | * Description: |
| 1115 | * This is a special case helper to splice directly between two |
| 1116 | * points, without requiring an explicit pipe. Internally an allocated |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 1117 | * pipe is cached in the process, and reused during the lifetime of |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1118 | * that process. |
| 1119 | * |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1120 | */ |
| 1121 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 1122 | splice_direct_actor *actor) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1123 | { |
| 1124 | struct pipe_inode_info *pipe; |
| 1125 | long ret, bytes; |
| 1126 | umode_t i_mode; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1127 | size_t len; |
| 1128 | int i, flags; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1129 | |
| 1130 | /* |
| 1131 | * We require the input being a regular file, as we don't want to |
| 1132 | * randomly drop data for eg socket -> socket splicing. Use the |
| 1133 | * piped splicing for that! |
| 1134 | */ |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1135 | i_mode = in->f_path.dentry->d_inode->i_mode; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1136 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) |
| 1137 | return -EINVAL; |
| 1138 | |
| 1139 | /* |
| 1140 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 1141 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 1142 | */ |
| 1143 | pipe = current->splice_pipe; |
Jens Axboe | 49570e9 | 2006-04-11 13:56:09 +0200 | [diff] [blame] | 1144 | if (unlikely(!pipe)) { |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1145 | pipe = alloc_pipe_info(NULL); |
| 1146 | if (!pipe) |
| 1147 | return -ENOMEM; |
| 1148 | |
| 1149 | /* |
| 1150 | * 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] | 1151 | * out of the pipe right after the splice_to_pipe(). So set |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1152 | * PIPE_READERS appropriately. |
| 1153 | */ |
| 1154 | pipe->readers = 1; |
| 1155 | |
| 1156 | current->splice_pipe = pipe; |
| 1157 | } |
| 1158 | |
| 1159 | /* |
Ingo Molnar | 73d62d8 | 2006-04-11 13:57:21 +0200 | [diff] [blame] | 1160 | * Do the splice. |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1161 | */ |
| 1162 | ret = 0; |
| 1163 | bytes = 0; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1164 | len = sd->total_len; |
| 1165 | flags = sd->flags; |
| 1166 | |
| 1167 | /* |
| 1168 | * Don't block on output, we have to drain the direct pipe. |
| 1169 | */ |
| 1170 | sd->flags &= ~SPLICE_F_NONBLOCK; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1171 | |
| 1172 | while (len) { |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1173 | size_t read_len; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1174 | loff_t pos = sd->pos, prev_pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1175 | |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1176 | ret = do_splice_to(in, &pos, pipe, len, flags); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1177 | if (unlikely(ret <= 0)) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1178 | goto out_release; |
| 1179 | |
| 1180 | read_len = ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1181 | sd->total_len = read_len; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1182 | |
| 1183 | /* |
| 1184 | * NOTE: nonblocking mode only applies to the input. We |
| 1185 | * must not do the output in nonblocking mode as then we |
| 1186 | * could get stuck data in the internal pipe: |
| 1187 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1188 | ret = actor(pipe, sd); |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1189 | if (unlikely(ret <= 0)) { |
| 1190 | sd->pos = prev_pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1191 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1192 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1193 | |
| 1194 | bytes += ret; |
| 1195 | len -= ret; |
Jens Axboe | bcd4f3a | 2007-07-16 14:41:49 +0200 | [diff] [blame] | 1196 | sd->pos = pos; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1197 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1198 | if (ret < read_len) { |
| 1199 | sd->pos = prev_pos + ret; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1200 | goto out_release; |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1201 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1202 | } |
| 1203 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1204 | done: |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1205 | pipe->nrbufs = pipe->curbuf = 0; |
Jens Axboe | 8084870 | 2008-01-30 12:24:48 +0100 | [diff] [blame] | 1206 | file_accessed(in); |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1207 | return bytes; |
| 1208 | |
| 1209 | out_release: |
| 1210 | /* |
| 1211 | * If we did an incomplete transfer we must release |
| 1212 | * the pipe buffers in question: |
| 1213 | */ |
| 1214 | for (i = 0; i < PIPE_BUFFERS; i++) { |
| 1215 | struct pipe_buffer *buf = pipe->bufs + i; |
| 1216 | |
| 1217 | if (buf->ops) { |
| 1218 | buf->ops->release(pipe, buf); |
| 1219 | buf->ops = NULL; |
| 1220 | } |
| 1221 | } |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1222 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1223 | if (!bytes) |
| 1224 | bytes = ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1225 | |
Jens Axboe | 9e97198 | 2008-01-29 21:05:57 +0100 | [diff] [blame] | 1226 | goto done; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1227 | } |
| 1228 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1229 | |
| 1230 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1231 | struct splice_desc *sd) |
| 1232 | { |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1233 | struct file *file = sd->u.file; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1234 | |
| 1235 | return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); |
| 1236 | } |
| 1237 | |
Jens Axboe | 932cc6d | 2007-06-21 13:10:21 +0200 | [diff] [blame] | 1238 | /** |
| 1239 | * do_splice_direct - splices data directly between two files |
| 1240 | * @in: file to splice from |
| 1241 | * @ppos: input file offset |
| 1242 | * @out: file to splice to |
| 1243 | * @len: number of bytes to splice |
| 1244 | * @flags: splice modifier flags |
| 1245 | * |
| 1246 | * Description: |
| 1247 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1248 | * doing it in the application would incur an extra system call |
| 1249 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1250 | * can splice directly through a process-private pipe. |
| 1251 | * |
| 1252 | */ |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1253 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1254 | size_t len, unsigned int flags) |
| 1255 | { |
| 1256 | struct splice_desc sd = { |
| 1257 | .len = len, |
| 1258 | .total_len = len, |
| 1259 | .flags = flags, |
| 1260 | .pos = *ppos, |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1261 | .u.file = out, |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1262 | }; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1263 | long ret; |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1264 | |
| 1265 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1266 | if (ret > 0) |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1267 | *ppos = sd.pos; |
Jens Axboe | 51a92c0 | 2007-07-13 14:11:43 +0200 | [diff] [blame] | 1268 | |
Jens Axboe | c66ab6f | 2007-06-12 21:17:17 +0200 | [diff] [blame] | 1269 | return ret; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1270 | } |
| 1271 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1272 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1273 | struct pipe_inode_info *opipe, |
| 1274 | size_t len, unsigned int flags); |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1275 | /* |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1276 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same |
| 1277 | * location, so checking ->i_pipe is not enough to verify that this is a |
| 1278 | * pipe. |
| 1279 | */ |
| 1280 | static inline struct pipe_inode_info *pipe_info(struct inode *inode) |
| 1281 | { |
| 1282 | if (S_ISFIFO(inode->i_mode)) |
| 1283 | return inode->i_pipe; |
| 1284 | |
| 1285 | return NULL; |
| 1286 | } |
| 1287 | |
| 1288 | /* |
Jens Axboe | 83f9135 | 2006-04-02 23:05:09 +0200 | [diff] [blame] | 1289 | * Determine where to splice to/from. |
| 1290 | */ |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1291 | static long do_splice(struct file *in, loff_t __user *off_in, |
| 1292 | struct file *out, loff_t __user *off_out, |
| 1293 | size_t len, unsigned int flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1294 | { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1295 | struct pipe_inode_info *ipipe; |
| 1296 | struct pipe_inode_info *opipe; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1297 | loff_t offset, *off; |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1298 | long ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1299 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1300 | ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1301 | opipe = pipe_info(out->f_path.dentry->d_inode); |
| 1302 | |
| 1303 | if (ipipe && opipe) { |
| 1304 | if (off_in || off_out) |
| 1305 | return -ESPIPE; |
| 1306 | |
| 1307 | if (!(in->f_mode & FMODE_READ)) |
| 1308 | return -EBADF; |
| 1309 | |
| 1310 | if (!(out->f_mode & FMODE_WRITE)) |
| 1311 | return -EBADF; |
| 1312 | |
| 1313 | /* Splicing to self would be fun, but... */ |
| 1314 | if (ipipe == opipe) |
| 1315 | return -EINVAL; |
| 1316 | |
| 1317 | return splice_pipe_to_pipe(ipipe, opipe, len, flags); |
| 1318 | } |
| 1319 | |
| 1320 | if (ipipe) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1321 | if (off_in) |
| 1322 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1323 | if (off_out) { |
Changli Gao | cc56f7d | 2009-11-04 09:09:52 +0100 | [diff] [blame] | 1324 | if (!out->f_op || !out->f_op->llseek || |
| 1325 | out->f_op->llseek == no_llseek) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1326 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1327 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1328 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1329 | off = &offset; |
| 1330 | } else |
| 1331 | off = &out->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1332 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1333 | ret = do_splice_from(ipipe, out, off, len, flags); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1334 | |
| 1335 | if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) |
| 1336 | ret = -EFAULT; |
| 1337 | |
| 1338 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1339 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1340 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1341 | if (opipe) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1342 | if (off_out) |
| 1343 | return -ESPIPE; |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1344 | if (off_in) { |
Changli Gao | cc56f7d | 2009-11-04 09:09:52 +0100 | [diff] [blame] | 1345 | if (!in->f_op || !in->f_op->llseek || |
| 1346 | in->f_op->llseek == no_llseek) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1347 | return -EINVAL; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1348 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 1349 | return -EFAULT; |
Jens Axboe | cbb7e57 | 2006-04-11 14:57:50 +0200 | [diff] [blame] | 1350 | off = &offset; |
| 1351 | } else |
| 1352 | off = &in->f_pos; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1353 | |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1354 | ret = do_splice_to(in, off, opipe, len, flags); |
Jens Axboe | a4514eb | 2006-04-19 15:57:05 +0200 | [diff] [blame] | 1355 | |
| 1356 | if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) |
| 1357 | ret = -EFAULT; |
| 1358 | |
| 1359 | return ret; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1360 | } |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1361 | |
| 1362 | return -EINVAL; |
| 1363 | } |
| 1364 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1365 | /* |
| 1366 | * Map an iov into an array of pages and offset/length tupples. With the |
| 1367 | * partial_page structure, we can map several non-contiguous ranges into |
| 1368 | * our ones pages[] map instead of splitting that operation into pieces. |
| 1369 | * Could easily be exported as a generic helper for other users, in which |
| 1370 | * case one would probably want to add a 'max_nr_pages' parameter as well. |
| 1371 | */ |
| 1372 | static int get_iovec_page_array(const struct iovec __user *iov, |
| 1373 | unsigned int nr_vecs, struct page **pages, |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1374 | struct partial_page *partial, int aligned) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1375 | { |
| 1376 | int buffers = 0, error = 0; |
| 1377 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1378 | while (nr_vecs) { |
| 1379 | unsigned long off, npages; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1380 | struct iovec entry; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1381 | void __user *base; |
| 1382 | size_t len; |
| 1383 | int i; |
| 1384 | |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1385 | error = -EFAULT; |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1386 | if (copy_from_user(&entry, iov, sizeof(entry))) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1387 | break; |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1388 | |
| 1389 | base = entry.iov_base; |
| 1390 | len = entry.iov_len; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1391 | |
| 1392 | /* |
| 1393 | * Sanity check this iovec. 0 read succeeds. |
| 1394 | */ |
Linus Torvalds | 7572395 | 2007-10-01 13:17:28 -0700 | [diff] [blame] | 1395 | error = 0; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1396 | if (unlikely(!len)) |
| 1397 | break; |
| 1398 | error = -EFAULT; |
Bastian Blank | 712a30e | 2008-02-10 16:47:57 +0200 | [diff] [blame] | 1399 | if (!access_ok(VERIFY_READ, base, len)) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1400 | break; |
| 1401 | |
| 1402 | /* |
| 1403 | * Get this base offset and number of pages, then map |
| 1404 | * in the user pages. |
| 1405 | */ |
| 1406 | off = (unsigned long) base & ~PAGE_MASK; |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1407 | |
| 1408 | /* |
| 1409 | * If asked for alignment, the offset must be zero and the |
| 1410 | * length a multiple of the PAGE_SIZE. |
| 1411 | */ |
| 1412 | error = -EINVAL; |
| 1413 | if (aligned && (off || len & ~PAGE_MASK)) |
| 1414 | break; |
| 1415 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1416 | npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1417 | if (npages > PIPE_BUFFERS - buffers) |
| 1418 | npages = PIPE_BUFFERS - buffers; |
| 1419 | |
Nick Piggin | bc40d73 | 2008-07-25 19:45:26 -0700 | [diff] [blame] | 1420 | error = get_user_pages_fast((unsigned long)base, npages, |
| 1421 | 0, &pages[buffers]); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1422 | |
| 1423 | if (unlikely(error <= 0)) |
| 1424 | break; |
| 1425 | |
| 1426 | /* |
| 1427 | * Fill this contiguous range into the partial page map. |
| 1428 | */ |
| 1429 | for (i = 0; i < error; i++) { |
Jens Axboe | 7591489 | 2006-05-02 12:57:18 +0200 | [diff] [blame] | 1430 | const int plen = min_t(size_t, len, PAGE_SIZE - off); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1431 | |
| 1432 | partial[buffers].offset = off; |
| 1433 | partial[buffers].len = plen; |
| 1434 | |
| 1435 | off = 0; |
| 1436 | len -= plen; |
| 1437 | buffers++; |
| 1438 | } |
| 1439 | |
| 1440 | /* |
| 1441 | * We didn't complete this iov, stop here since it probably |
| 1442 | * means we have to move some of this into a pipe to |
| 1443 | * be able to continue. |
| 1444 | */ |
| 1445 | if (len) |
| 1446 | break; |
| 1447 | |
| 1448 | /* |
| 1449 | * Don't continue if we mapped fewer pages than we asked for, |
| 1450 | * or if we mapped the max number of pages that we have |
| 1451 | * room for. |
| 1452 | */ |
| 1453 | if (error < npages || buffers == PIPE_BUFFERS) |
| 1454 | break; |
| 1455 | |
| 1456 | nr_vecs--; |
| 1457 | iov++; |
| 1458 | } |
| 1459 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1460 | if (buffers) |
| 1461 | return buffers; |
| 1462 | |
| 1463 | return error; |
| 1464 | } |
| 1465 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1466 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1467 | struct splice_desc *sd) |
| 1468 | { |
| 1469 | char *src; |
| 1470 | int ret; |
| 1471 | |
Jens Axboe | cac36bb | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 1472 | ret = buf->ops->confirm(pipe, buf); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1473 | if (unlikely(ret)) |
| 1474 | return ret; |
| 1475 | |
| 1476 | /* |
| 1477 | * See if we can use the atomic maps, by prefaulting in the |
| 1478 | * pages and doing an atomic copy |
| 1479 | */ |
| 1480 | if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { |
| 1481 | src = buf->ops->map(pipe, buf, 1); |
| 1482 | ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, |
| 1483 | sd->len); |
| 1484 | buf->ops->unmap(pipe, buf, src); |
| 1485 | if (!ret) { |
| 1486 | ret = sd->len; |
| 1487 | goto out; |
| 1488 | } |
| 1489 | } |
| 1490 | |
| 1491 | /* |
| 1492 | * No dice, use slow non-atomic map and copy |
| 1493 | */ |
| 1494 | src = buf->ops->map(pipe, buf, 0); |
| 1495 | |
| 1496 | ret = sd->len; |
| 1497 | if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) |
| 1498 | ret = -EFAULT; |
| 1499 | |
Jens Axboe | 6866bef | 2007-10-16 10:01:29 +0200 | [diff] [blame] | 1500 | buf->ops->unmap(pipe, buf, src); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1501 | out: |
| 1502 | if (ret > 0) |
| 1503 | sd->u.userptr += ret; |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1504 | return ret; |
| 1505 | } |
| 1506 | |
| 1507 | /* |
| 1508 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1509 | * as a simple copy of the pipes pages to the user iov. |
| 1510 | */ |
| 1511 | static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, |
| 1512 | unsigned long nr_segs, unsigned int flags) |
| 1513 | { |
| 1514 | struct pipe_inode_info *pipe; |
| 1515 | struct splice_desc sd; |
| 1516 | ssize_t size; |
| 1517 | int error; |
| 1518 | long ret; |
| 1519 | |
| 1520 | pipe = pipe_info(file->f_path.dentry->d_inode); |
| 1521 | if (!pipe) |
| 1522 | return -EBADF; |
| 1523 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1524 | pipe_lock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1525 | |
| 1526 | error = ret = 0; |
| 1527 | while (nr_segs) { |
| 1528 | void __user *base; |
| 1529 | size_t len; |
| 1530 | |
| 1531 | /* |
| 1532 | * Get user address base and length for this iovec. |
| 1533 | */ |
| 1534 | error = get_user(base, &iov->iov_base); |
| 1535 | if (unlikely(error)) |
| 1536 | break; |
| 1537 | error = get_user(len, &iov->iov_len); |
| 1538 | if (unlikely(error)) |
| 1539 | break; |
| 1540 | |
| 1541 | /* |
| 1542 | * Sanity check this iovec. 0 read succeeds. |
| 1543 | */ |
| 1544 | if (unlikely(!len)) |
| 1545 | break; |
| 1546 | if (unlikely(!base)) { |
| 1547 | error = -EFAULT; |
| 1548 | break; |
| 1549 | } |
| 1550 | |
Jens Axboe | 8811930 | 2008-02-08 08:49:14 -0800 | [diff] [blame] | 1551 | if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { |
| 1552 | error = -EFAULT; |
| 1553 | break; |
| 1554 | } |
| 1555 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1556 | sd.len = 0; |
| 1557 | sd.total_len = len; |
| 1558 | sd.flags = flags; |
| 1559 | sd.u.userptr = base; |
| 1560 | sd.pos = 0; |
| 1561 | |
| 1562 | size = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1563 | if (size < 0) { |
| 1564 | if (!ret) |
| 1565 | ret = size; |
| 1566 | |
| 1567 | break; |
| 1568 | } |
| 1569 | |
| 1570 | ret += size; |
| 1571 | |
| 1572 | if (size < len) |
| 1573 | break; |
| 1574 | |
| 1575 | nr_segs--; |
| 1576 | iov++; |
| 1577 | } |
| 1578 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1579 | pipe_unlock(pipe); |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1580 | |
| 1581 | if (!ret) |
| 1582 | ret = error; |
| 1583 | |
| 1584 | return ret; |
| 1585 | } |
| 1586 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1587 | /* |
| 1588 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1589 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1590 | * to file). In both cases the output is a pipe, naturally. |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1591 | */ |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1592 | static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, |
| 1593 | unsigned long nr_segs, unsigned int flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1594 | { |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1595 | struct pipe_inode_info *pipe; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1596 | struct page *pages[PIPE_BUFFERS]; |
| 1597 | struct partial_page partial[PIPE_BUFFERS]; |
| 1598 | struct splice_pipe_desc spd = { |
| 1599 | .pages = pages, |
| 1600 | .partial = partial, |
| 1601 | .flags = flags, |
| 1602 | .ops = &user_page_pipe_buf_ops, |
Jens Axboe | bbdfc2f | 2007-11-06 23:29:47 -0800 | [diff] [blame] | 1603 | .spd_release = spd_release_page, |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1604 | }; |
| 1605 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1606 | pipe = pipe_info(file->f_path.dentry->d_inode); |
Jens Axboe | ddac0d3 | 2006-11-04 12:49:32 +0100 | [diff] [blame] | 1607 | if (!pipe) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1608 | return -EBADF; |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1609 | |
Jens Axboe | 7afa6fd | 2006-05-01 20:02:33 +0200 | [diff] [blame] | 1610 | spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, |
| 1611 | flags & SPLICE_F_GIFT); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1612 | if (spd.nr_pages <= 0) |
| 1613 | return spd.nr_pages; |
| 1614 | |
Jens Axboe | 00522fb | 2006-04-26 14:39:29 +0200 | [diff] [blame] | 1615 | return splice_to_pipe(pipe, &spd); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1616 | } |
| 1617 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1618 | /* |
| 1619 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1620 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1621 | * operation that can be supported without any funky alignment restrictions |
| 1622 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1623 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1624 | * solutions for that: |
| 1625 | * |
| 1626 | * - memcpy() the data internally, at which point we might as well just |
| 1627 | * do a regular read() on the buffer anyway. |
| 1628 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1629 | * has restriction limitations on both ends of the pipe). |
| 1630 | * |
| 1631 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1632 | * |
| 1633 | */ |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1634 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, |
| 1635 | unsigned long, nr_segs, unsigned int, flags) |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1636 | { |
| 1637 | struct file *file; |
| 1638 | long error; |
| 1639 | int fput; |
| 1640 | |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1641 | if (unlikely(nr_segs > UIO_MAXIOV)) |
| 1642 | return -EINVAL; |
| 1643 | else if (unlikely(!nr_segs)) |
| 1644 | return 0; |
| 1645 | |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1646 | error = -EBADF; |
| 1647 | file = fget_light(fd, &fput); |
| 1648 | if (file) { |
| 1649 | if (file->f_mode & FMODE_WRITE) |
Jens Axboe | 6a14b90 | 2007-06-14 13:08:55 +0200 | [diff] [blame] | 1650 | error = vmsplice_to_pipe(file, iov, nr_segs, flags); |
| 1651 | else if (file->f_mode & FMODE_READ) |
| 1652 | error = vmsplice_to_user(file, iov, nr_segs, flags); |
Jens Axboe | 912d35f | 2006-04-26 10:59:21 +0200 | [diff] [blame] | 1653 | |
| 1654 | fput_light(file, fput); |
| 1655 | } |
| 1656 | |
| 1657 | return error; |
| 1658 | } |
| 1659 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 1660 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
| 1661 | int, fd_out, loff_t __user *, off_out, |
| 1662 | size_t, len, unsigned int, flags) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1663 | { |
| 1664 | long error; |
| 1665 | struct file *in, *out; |
| 1666 | int fput_in, fput_out; |
| 1667 | |
| 1668 | if (unlikely(!len)) |
| 1669 | return 0; |
| 1670 | |
| 1671 | error = -EBADF; |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1672 | in = fget_light(fd_in, &fput_in); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1673 | if (in) { |
| 1674 | if (in->f_mode & FMODE_READ) { |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1675 | out = fget_light(fd_out, &fput_out); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1676 | if (out) { |
| 1677 | if (out->f_mode & FMODE_WRITE) |
Ingo Molnar | 529565d | 2006-04-10 15:18:58 +0200 | [diff] [blame] | 1678 | error = do_splice(in, off_in, |
| 1679 | out, off_out, |
| 1680 | len, flags); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 1681 | fput_light(out, fput_out); |
| 1682 | } |
| 1683 | } |
| 1684 | |
| 1685 | fput_light(in, fput_in); |
| 1686 | } |
| 1687 | |
| 1688 | return error; |
| 1689 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1690 | |
| 1691 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1692 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1693 | * return an appropriate error. |
| 1694 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1695 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1696 | { |
| 1697 | int ret; |
| 1698 | |
| 1699 | /* |
| 1700 | * Check ->nrbufs without the inode lock first. This function |
| 1701 | * is speculative anyways, so missing one is ok. |
| 1702 | */ |
| 1703 | if (pipe->nrbufs) |
| 1704 | return 0; |
| 1705 | |
| 1706 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1707 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1708 | |
| 1709 | while (!pipe->nrbufs) { |
| 1710 | if (signal_pending(current)) { |
| 1711 | ret = -ERESTARTSYS; |
| 1712 | break; |
| 1713 | } |
| 1714 | if (!pipe->writers) |
| 1715 | break; |
| 1716 | if (!pipe->waiting_writers) { |
| 1717 | if (flags & SPLICE_F_NONBLOCK) { |
| 1718 | ret = -EAGAIN; |
| 1719 | break; |
| 1720 | } |
| 1721 | } |
| 1722 | pipe_wait(pipe); |
| 1723 | } |
| 1724 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1725 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1726 | return ret; |
| 1727 | } |
| 1728 | |
| 1729 | /* |
| 1730 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1731 | * return an appropriate error. |
| 1732 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1733 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1734 | { |
| 1735 | int ret; |
| 1736 | |
| 1737 | /* |
| 1738 | * Check ->nrbufs without the inode lock first. This function |
| 1739 | * is speculative anyways, so missing one is ok. |
| 1740 | */ |
| 1741 | if (pipe->nrbufs < PIPE_BUFFERS) |
| 1742 | return 0; |
| 1743 | |
| 1744 | ret = 0; |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1745 | pipe_lock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1746 | |
| 1747 | while (pipe->nrbufs >= PIPE_BUFFERS) { |
| 1748 | if (!pipe->readers) { |
| 1749 | send_sig(SIGPIPE, current, 0); |
| 1750 | ret = -EPIPE; |
| 1751 | break; |
| 1752 | } |
| 1753 | if (flags & SPLICE_F_NONBLOCK) { |
| 1754 | ret = -EAGAIN; |
| 1755 | break; |
| 1756 | } |
| 1757 | if (signal_pending(current)) { |
| 1758 | ret = -ERESTARTSYS; |
| 1759 | break; |
| 1760 | } |
| 1761 | pipe->waiting_writers++; |
| 1762 | pipe_wait(pipe); |
| 1763 | pipe->waiting_writers--; |
| 1764 | } |
| 1765 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1766 | pipe_unlock(pipe); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1767 | return ret; |
| 1768 | } |
| 1769 | |
| 1770 | /* |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1771 | * Splice contents of ipipe to opipe. |
| 1772 | */ |
| 1773 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1774 | struct pipe_inode_info *opipe, |
| 1775 | size_t len, unsigned int flags) |
| 1776 | { |
| 1777 | struct pipe_buffer *ibuf, *obuf; |
| 1778 | int ret = 0, nbuf; |
| 1779 | bool input_wakeup = false; |
| 1780 | |
| 1781 | |
| 1782 | retry: |
| 1783 | ret = ipipe_prep(ipipe, flags); |
| 1784 | if (ret) |
| 1785 | return ret; |
| 1786 | |
| 1787 | ret = opipe_prep(opipe, flags); |
| 1788 | if (ret) |
| 1789 | return ret; |
| 1790 | |
| 1791 | /* |
| 1792 | * Potential ABBA deadlock, work around it by ordering lock |
| 1793 | * grabbing by pipe info address. Otherwise two different processes |
| 1794 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1795 | */ |
| 1796 | pipe_double_lock(ipipe, opipe); |
| 1797 | |
| 1798 | do { |
| 1799 | if (!opipe->readers) { |
| 1800 | send_sig(SIGPIPE, current, 0); |
| 1801 | if (!ret) |
| 1802 | ret = -EPIPE; |
| 1803 | break; |
| 1804 | } |
| 1805 | |
| 1806 | if (!ipipe->nrbufs && !ipipe->writers) |
| 1807 | break; |
| 1808 | |
| 1809 | /* |
| 1810 | * Cannot make any progress, because either the input |
| 1811 | * pipe is empty or the output pipe is full. |
| 1812 | */ |
| 1813 | if (!ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) { |
| 1814 | /* Already processed some buffers, break */ |
| 1815 | if (ret) |
| 1816 | break; |
| 1817 | |
| 1818 | if (flags & SPLICE_F_NONBLOCK) { |
| 1819 | ret = -EAGAIN; |
| 1820 | break; |
| 1821 | } |
| 1822 | |
| 1823 | /* |
| 1824 | * We raced with another reader/writer and haven't |
| 1825 | * managed to process any buffers. A zero return |
| 1826 | * value means EOF, so retry instead. |
| 1827 | */ |
| 1828 | pipe_unlock(ipipe); |
| 1829 | pipe_unlock(opipe); |
| 1830 | goto retry; |
| 1831 | } |
| 1832 | |
| 1833 | ibuf = ipipe->bufs + ipipe->curbuf; |
| 1834 | nbuf = (opipe->curbuf + opipe->nrbufs) % PIPE_BUFFERS; |
| 1835 | obuf = opipe->bufs + nbuf; |
| 1836 | |
| 1837 | if (len >= ibuf->len) { |
| 1838 | /* |
| 1839 | * Simply move the whole buffer from ipipe to opipe |
| 1840 | */ |
| 1841 | *obuf = *ibuf; |
| 1842 | ibuf->ops = NULL; |
| 1843 | opipe->nrbufs++; |
| 1844 | ipipe->curbuf = (ipipe->curbuf + 1) % PIPE_BUFFERS; |
| 1845 | ipipe->nrbufs--; |
| 1846 | input_wakeup = true; |
| 1847 | } else { |
| 1848 | /* |
| 1849 | * Get a reference to this pipe buffer, |
| 1850 | * so we can copy the contents over. |
| 1851 | */ |
| 1852 | ibuf->ops->get(ipipe, ibuf); |
| 1853 | *obuf = *ibuf; |
| 1854 | |
| 1855 | /* |
| 1856 | * Don't inherit the gift flag, we need to |
| 1857 | * prevent multiple steals of this page. |
| 1858 | */ |
| 1859 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1860 | |
| 1861 | obuf->len = len; |
| 1862 | opipe->nrbufs++; |
| 1863 | ibuf->offset += obuf->len; |
| 1864 | ibuf->len -= obuf->len; |
| 1865 | } |
| 1866 | ret += obuf->len; |
| 1867 | len -= obuf->len; |
| 1868 | } while (len); |
| 1869 | |
| 1870 | pipe_unlock(ipipe); |
| 1871 | pipe_unlock(opipe); |
| 1872 | |
| 1873 | /* |
| 1874 | * If we put data in the output pipe, wakeup any potential readers. |
| 1875 | */ |
| 1876 | if (ret > 0) { |
| 1877 | smp_mb(); |
| 1878 | if (waitqueue_active(&opipe->wait)) |
| 1879 | wake_up_interruptible(&opipe->wait); |
| 1880 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1881 | } |
| 1882 | if (input_wakeup) |
| 1883 | wakeup_pipe_writers(ipipe); |
| 1884 | |
| 1885 | return ret; |
| 1886 | } |
| 1887 | |
| 1888 | /* |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1889 | * Link contents of ipipe to opipe. |
| 1890 | */ |
| 1891 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1892 | struct pipe_inode_info *opipe, |
| 1893 | size_t len, unsigned int flags) |
| 1894 | { |
| 1895 | struct pipe_buffer *ibuf, *obuf; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1896 | int ret = 0, i = 0, nbuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1897 | |
| 1898 | /* |
| 1899 | * Potential ABBA deadlock, work around it by ordering lock |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1900 | * grabbing by pipe info address. Otherwise two different processes |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1901 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1902 | */ |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1903 | pipe_double_lock(ipipe, opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1904 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1905 | do { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1906 | if (!opipe->readers) { |
| 1907 | send_sig(SIGPIPE, current, 0); |
| 1908 | if (!ret) |
| 1909 | ret = -EPIPE; |
| 1910 | break; |
| 1911 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1912 | |
| 1913 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1914 | * If we have iterated all input buffers or ran out of |
| 1915 | * output room, break. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1916 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1917 | if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1918 | break; |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1919 | |
| 1920 | ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1)); |
| 1921 | nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1); |
| 1922 | |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1923 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1924 | * Get a reference to this pipe buffer, |
| 1925 | * so we can copy the contents over. |
Jens Axboe | 2a27250 | 2006-04-19 15:56:40 +0200 | [diff] [blame] | 1926 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1927 | ibuf->ops->get(ipipe, ibuf); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1928 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1929 | obuf = opipe->bufs + nbuf; |
| 1930 | *obuf = *ibuf; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1931 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1932 | /* |
| 1933 | * Don't inherit the gift flag, we need to |
| 1934 | * prevent multiple steals of this page. |
| 1935 | */ |
| 1936 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1937 | |
| 1938 | if (obuf->len > len) |
| 1939 | obuf->len = len; |
| 1940 | |
| 1941 | opipe->nrbufs++; |
| 1942 | ret += obuf->len; |
| 1943 | len -= obuf->len; |
| 1944 | i++; |
| 1945 | } while (len); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1946 | |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1947 | /* |
| 1948 | * return EAGAIN if we have the potential of some data in the |
| 1949 | * future, otherwise just return 0 |
| 1950 | */ |
| 1951 | if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) |
| 1952 | ret = -EAGAIN; |
| 1953 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 1954 | pipe_unlock(ipipe); |
| 1955 | pipe_unlock(opipe); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1956 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1957 | /* |
| 1958 | * If we put data in the output pipe, wakeup any potential readers. |
| 1959 | */ |
| 1960 | if (ret > 0) { |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1961 | smp_mb(); |
| 1962 | if (waitqueue_active(&opipe->wait)) |
| 1963 | wake_up_interruptible(&opipe->wait); |
| 1964 | kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN); |
| 1965 | } |
| 1966 | |
| 1967 | return ret; |
| 1968 | } |
| 1969 | |
| 1970 | /* |
| 1971 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1972 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1973 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1974 | * applicable one is SPLICE_F_NONBLOCK. |
| 1975 | */ |
| 1976 | static long do_tee(struct file *in, struct file *out, size_t len, |
| 1977 | unsigned int flags) |
| 1978 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1979 | struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode); |
| 1980 | 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] | 1981 | int ret = -EINVAL; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1982 | |
| 1983 | /* |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1984 | * Duplicate the contents of ipipe to opipe without actually |
| 1985 | * copying the data. |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1986 | */ |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1987 | if (ipipe && opipe && ipipe != opipe) { |
| 1988 | /* |
| 1989 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1990 | * ordering doesn't really matter. |
| 1991 | */ |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1992 | ret = ipipe_prep(ipipe, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1993 | if (!ret) { |
Miklos Szeredi | 7c77f0b | 2009-05-07 15:37:35 +0200 | [diff] [blame] | 1994 | ret = opipe_prep(opipe, flags); |
Jens Axboe | 02cf01a | 2008-02-20 10:34:51 +0100 | [diff] [blame] | 1995 | if (!ret) |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1996 | ret = link_pipe(ipipe, opipe, len, flags); |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 1997 | } |
| 1998 | } |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 1999 | |
Jens Axboe | aadd06e | 2006-07-10 11:00:01 +0200 | [diff] [blame] | 2000 | return ret; |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 2001 | } |
| 2002 | |
Heiko Carstens | 836f92a | 2009-01-14 14:14:33 +0100 | [diff] [blame] | 2003 | 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] | 2004 | { |
| 2005 | struct file *in; |
| 2006 | int error, fput_in; |
| 2007 | |
| 2008 | if (unlikely(!len)) |
| 2009 | return 0; |
| 2010 | |
| 2011 | error = -EBADF; |
| 2012 | in = fget_light(fdin, &fput_in); |
| 2013 | if (in) { |
| 2014 | if (in->f_mode & FMODE_READ) { |
| 2015 | int fput_out; |
| 2016 | struct file *out = fget_light(fdout, &fput_out); |
| 2017 | |
| 2018 | if (out) { |
| 2019 | if (out->f_mode & FMODE_WRITE) |
| 2020 | error = do_tee(in, out, len, flags); |
| 2021 | fput_light(out, fput_out); |
| 2022 | } |
| 2023 | } |
| 2024 | fput_light(in, fput_in); |
| 2025 | } |
| 2026 | |
| 2027 | return error; |
| 2028 | } |