Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/pipe.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1999 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | #include <linux/mm.h> |
| 8 | #include <linux/file.h> |
| 9 | #include <linux/poll.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/fs.h> |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 14 | #include <linux/log2.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/mount.h> |
Muthu Kumar | b502bd1 | 2012-03-23 15:01:50 -0700 | [diff] [blame] | 16 | #include <linux/magic.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/pipe_fs_i.h> |
| 18 | #include <linux/uio.h> |
| 19 | #include <linux/highmem.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 20 | #include <linux/pagemap.h> |
Al Viro | db34950 | 2007-02-07 01:48:00 -0500 | [diff] [blame] | 21 | #include <linux/audit.h> |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 22 | #include <linux/syscalls.h> |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 23 | #include <linux/fcntl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | |
| 25 | #include <asm/uaccess.h> |
| 26 | #include <asm/ioctls.h> |
| 27 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 28 | #include "internal.h" |
| 29 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | /* |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 31 | * The max size that a non-root user is allowed to grow the pipe. Can |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 32 | * be set by root in /proc/sys/fs/pipe-max-size |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 33 | */ |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 34 | unsigned int pipe_max_size = 1048576; |
| 35 | |
| 36 | /* |
| 37 | * Minimum pipe size, as required by POSIX |
| 38 | */ |
| 39 | unsigned int pipe_min_size = PAGE_SIZE; |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 40 | |
| 41 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | * We use a start+len construction, which provides full use of the |
| 43 | * allocated memory. |
| 44 | * -- Florian Coosmann (FGC) |
| 45 | * |
| 46 | * Reads with count = 0 should always return 0. |
| 47 | * -- Julian Bradfield 1999-06-07. |
| 48 | * |
| 49 | * FIFOs and Pipes now generate SIGIO for both readers and writers. |
| 50 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 |
| 51 | * |
| 52 | * pipe_read & write cleanup |
| 53 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 |
| 54 | */ |
| 55 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 56 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
| 57 | { |
Al Viro | 6447a3c | 2013-03-21 11:01:38 -0400 | [diff] [blame] | 58 | if (pipe->files) |
Al Viro | 72b0d9a | 2013-03-21 02:32:24 -0400 | [diff] [blame] | 59 | mutex_lock_nested(&pipe->mutex, subclass); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 60 | } |
| 61 | |
| 62 | void pipe_lock(struct pipe_inode_info *pipe) |
| 63 | { |
| 64 | /* |
| 65 | * pipe_lock() nests non-pipe inode locks (for writing to a file) |
| 66 | */ |
| 67 | pipe_lock_nested(pipe, I_MUTEX_PARENT); |
| 68 | } |
| 69 | EXPORT_SYMBOL(pipe_lock); |
| 70 | |
| 71 | void pipe_unlock(struct pipe_inode_info *pipe) |
| 72 | { |
Al Viro | 6447a3c | 2013-03-21 11:01:38 -0400 | [diff] [blame] | 73 | if (pipe->files) |
Al Viro | 72b0d9a | 2013-03-21 02:32:24 -0400 | [diff] [blame] | 74 | mutex_unlock(&pipe->mutex); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 75 | } |
| 76 | EXPORT_SYMBOL(pipe_unlock); |
| 77 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 78 | static inline void __pipe_lock(struct pipe_inode_info *pipe) |
| 79 | { |
| 80 | mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT); |
| 81 | } |
| 82 | |
| 83 | static inline void __pipe_unlock(struct pipe_inode_info *pipe) |
| 84 | { |
| 85 | mutex_unlock(&pipe->mutex); |
| 86 | } |
| 87 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 88 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
| 89 | struct pipe_inode_info *pipe2) |
| 90 | { |
| 91 | BUG_ON(pipe1 == pipe2); |
| 92 | |
| 93 | if (pipe1 < pipe2) { |
| 94 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); |
| 95 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); |
| 96 | } else { |
Peter Zijlstra | 023d43c | 2009-07-21 10:09:23 +0200 | [diff] [blame] | 97 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
| 98 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 99 | } |
| 100 | } |
| 101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 103 | void pipe_wait(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | { |
| 105 | DEFINE_WAIT(wait); |
| 106 | |
Ingo Molnar | d79fc0f | 2005-09-10 00:26:12 -0700 | [diff] [blame] | 107 | /* |
| 108 | * Pipes are system-local resources, so sleeping on them |
| 109 | * is considered a noninteractive wait: |
| 110 | */ |
Mike Galbraith | af92723 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 111 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 112 | pipe_unlock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | schedule(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 114 | finish_wait(&pipe->wait, &wait); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 115 | pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | } |
| 117 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 118 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 119 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
| 120 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | { |
| 122 | unsigned long copy; |
| 123 | |
| 124 | while (len > 0) { |
| 125 | while (!iov->iov_len) |
| 126 | iov++; |
| 127 | copy = min_t(unsigned long, len, iov->iov_len); |
| 128 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 129 | if (atomic) { |
| 130 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) |
| 131 | return -EFAULT; |
| 132 | } else { |
| 133 | if (copy_from_user(to, iov->iov_base, copy)) |
| 134 | return -EFAULT; |
| 135 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | to += copy; |
| 137 | len -= copy; |
| 138 | iov->iov_base += copy; |
| 139 | iov->iov_len -= copy; |
| 140 | } |
| 141 | return 0; |
| 142 | } |
| 143 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 144 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 145 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
| 146 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | { |
| 148 | unsigned long copy; |
| 149 | |
| 150 | while (len > 0) { |
| 151 | while (!iov->iov_len) |
| 152 | iov++; |
| 153 | copy = min_t(unsigned long, len, iov->iov_len); |
| 154 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 155 | if (atomic) { |
| 156 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) |
| 157 | return -EFAULT; |
| 158 | } else { |
| 159 | if (copy_to_user(iov->iov_base, from, copy)) |
| 160 | return -EFAULT; |
| 161 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | from += copy; |
| 163 | len -= copy; |
| 164 | iov->iov_base += copy; |
| 165 | iov->iov_len -= copy; |
| 166 | } |
| 167 | return 0; |
| 168 | } |
| 169 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 170 | /* |
| 171 | * Attempt to pre-fault in the user memory, so we can use atomic copies. |
| 172 | * Returns the number of bytes not faulted in. |
| 173 | */ |
| 174 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) |
| 175 | { |
| 176 | while (!iov->iov_len) |
| 177 | iov++; |
| 178 | |
| 179 | while (len > 0) { |
| 180 | unsigned long this_len; |
| 181 | |
| 182 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 183 | if (fault_in_pages_writeable(iov->iov_base, this_len)) |
| 184 | break; |
| 185 | |
| 186 | len -= this_len; |
| 187 | iov++; |
| 188 | } |
| 189 | |
| 190 | return len; |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Pre-fault in the user memory, so we can use atomic copies. |
| 195 | */ |
| 196 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) |
| 197 | { |
| 198 | while (!iov->iov_len) |
| 199 | iov++; |
| 200 | |
| 201 | while (len > 0) { |
| 202 | unsigned long this_len; |
| 203 | |
| 204 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 205 | fault_in_pages_readable(iov->iov_base, this_len); |
| 206 | len -= this_len; |
| 207 | iov++; |
| 208 | } |
| 209 | } |
| 210 | |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 211 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
| 212 | struct pipe_buffer *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | { |
| 214 | struct page *page = buf->page; |
| 215 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 216 | /* |
| 217 | * If nobody else uses this page, and we don't already have a |
| 218 | * temporary page, let's keep track of it as a one-deep |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 219 | * allocation cache. (Otherwise just release our reference to it) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 220 | */ |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 221 | if (page_count(page) == 1 && !pipe->tmp_page) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 222 | pipe->tmp_page = page; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 223 | else |
| 224 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | } |
| 226 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 227 | /** |
| 228 | * generic_pipe_buf_map - virtually map a pipe buffer |
| 229 | * @pipe: the pipe that the buffer belongs to |
| 230 | * @buf: the buffer that should be mapped |
| 231 | * @atomic: whether to use an atomic map |
| 232 | * |
| 233 | * Description: |
| 234 | * This function returns a kernel virtual address mapping for the |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 235 | * pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 236 | * and the caller has to be careful not to fault before calling |
| 237 | * the unmap function. |
| 238 | * |
Cong Wang | 2164d33 | 2012-06-23 11:33:51 +0800 | [diff] [blame] | 239 | * Note that this function calls kmap_atomic() if @atomic != 0. |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 240 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 241 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 242 | struct pipe_buffer *buf, int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 244 | if (atomic) { |
| 245 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 246 | return kmap_atomic(buf->page); |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 247 | } |
| 248 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | return kmap(buf->page); |
| 250 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 251 | EXPORT_SYMBOL(generic_pipe_buf_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 253 | /** |
| 254 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer |
| 255 | * @pipe: the pipe that the buffer belongs to |
| 256 | * @buf: the buffer that should be unmapped |
| 257 | * @map_data: the data that the mapping function returned |
| 258 | * |
| 259 | * Description: |
| 260 | * This function undoes the mapping that ->map() provided. |
| 261 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 262 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 263 | struct pipe_buffer *buf, void *map_data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 265 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
| 266 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 267 | kunmap_atomic(map_data); |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 268 | } else |
| 269 | kunmap(buf->page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 271 | EXPORT_SYMBOL(generic_pipe_buf_unmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 273 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 274 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 275 | * @pipe: the pipe that the buffer belongs to |
| 276 | * @buf: the buffer to attempt to steal |
| 277 | * |
| 278 | * Description: |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 279 | * This function attempts to steal the &struct page attached to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 280 | * @buf. If successful, this function returns 0 and returns with |
| 281 | * the page locked. The caller may then reuse the page for whatever |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 282 | * he wishes; the typical use is insertion into a different file |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 283 | * page cache. |
| 284 | */ |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 285 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 286 | struct pipe_buffer *buf) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 287 | { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 288 | struct page *page = buf->page; |
| 289 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 290 | /* |
| 291 | * A reference of one is golden, that means that the owner of this |
| 292 | * page is the only one holding a reference to it. lock the page |
| 293 | * and return OK. |
| 294 | */ |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 295 | if (page_count(page) == 1) { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 296 | lock_page(page); |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 301 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 302 | EXPORT_SYMBOL(generic_pipe_buf_steal); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 303 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 304 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 305 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 306 | * @pipe: the pipe that the buffer belongs to |
| 307 | * @buf: the buffer to get a reference to |
| 308 | * |
| 309 | * Description: |
| 310 | * This function grabs an extra reference to @buf. It's used in |
| 311 | * in the tee() system call, when we duplicate the buffers in one |
| 312 | * pipe into another. |
| 313 | */ |
| 314 | void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 315 | { |
| 316 | page_cache_get(buf->page); |
| 317 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 318 | EXPORT_SYMBOL(generic_pipe_buf_get); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 319 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 320 | /** |
| 321 | * generic_pipe_buf_confirm - verify contents of the pipe buffer |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 322 | * @info: the pipe that the buffer belongs to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 323 | * @buf: the buffer to confirm |
| 324 | * |
| 325 | * Description: |
| 326 | * This function does nothing, because the generic pipe code uses |
| 327 | * pages that are always good when inserted into the pipe. |
| 328 | */ |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 329 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
| 330 | struct pipe_buffer *buf) |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 331 | { |
| 332 | return 0; |
| 333 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 334 | EXPORT_SYMBOL(generic_pipe_buf_confirm); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 335 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 336 | /** |
| 337 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer |
| 338 | * @pipe: the pipe that the buffer belongs to |
| 339 | * @buf: the buffer to put a reference to |
| 340 | * |
| 341 | * Description: |
| 342 | * This function releases a reference to @buf. |
| 343 | */ |
| 344 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, |
| 345 | struct pipe_buffer *buf) |
| 346 | { |
| 347 | page_cache_release(buf->page); |
| 348 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 349 | EXPORT_SYMBOL(generic_pipe_buf_release); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 350 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 351 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | .can_merge = 1, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 353 | .map = generic_pipe_buf_map, |
| 354 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 355 | .confirm = generic_pipe_buf_confirm, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | .release = anon_pipe_buf_release, |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 357 | .steal = generic_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 358 | .get = generic_pipe_buf_get, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | }; |
| 360 | |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 361 | static const struct pipe_buf_operations packet_pipe_buf_ops = { |
| 362 | .can_merge = 0, |
| 363 | .map = generic_pipe_buf_map, |
| 364 | .unmap = generic_pipe_buf_unmap, |
| 365 | .confirm = generic_pipe_buf_confirm, |
| 366 | .release = anon_pipe_buf_release, |
| 367 | .steal = generic_pipe_buf_steal, |
| 368 | .get = generic_pipe_buf_get, |
| 369 | }; |
| 370 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 372 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
| 373 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 375 | struct file *filp = iocb->ki_filp; |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 376 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | int do_wakeup; |
| 378 | ssize_t ret; |
| 379 | struct iovec *iov = (struct iovec *)_iov; |
| 380 | size_t total_len; |
| 381 | |
| 382 | total_len = iov_length(iov, nr_segs); |
| 383 | /* Null read succeeds. */ |
| 384 | if (unlikely(total_len == 0)) |
| 385 | return 0; |
| 386 | |
| 387 | do_wakeup = 0; |
| 388 | ret = 0; |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 389 | __pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | for (;;) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 391 | int bufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | if (bufs) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 393 | int curbuf = pipe->curbuf; |
| 394 | struct pipe_buffer *buf = pipe->bufs + curbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 395 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | void *addr; |
| 397 | size_t chars = buf->len; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 398 | int error, atomic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | |
| 400 | if (chars > total_len) |
| 401 | chars = total_len; |
| 402 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 403 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 404 | if (error) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 405 | if (!ret) |
Nicolas Kaiser | e5953cb | 2010-10-21 14:56:00 +0200 | [diff] [blame] | 406 | ret = error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 407 | break; |
| 408 | } |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 409 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 410 | atomic = !iov_fault_in_pages_write(iov, chars); |
| 411 | redo: |
| 412 | addr = ops->map(pipe, buf, atomic); |
| 413 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); |
| 414 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 416 | /* |
| 417 | * Just retry with the slow path if we failed. |
| 418 | */ |
| 419 | if (atomic) { |
| 420 | atomic = 0; |
| 421 | goto redo; |
| 422 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 423 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 424 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | break; |
| 426 | } |
| 427 | ret += chars; |
| 428 | buf->offset += chars; |
| 429 | buf->len -= chars; |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 430 | |
| 431 | /* Was it a packet buffer? Clean up and exit */ |
| 432 | if (buf->flags & PIPE_BUF_FLAG_PACKET) { |
| 433 | total_len = chars; |
| 434 | buf->len = 0; |
| 435 | } |
| 436 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | if (!buf->len) { |
| 438 | buf->ops = NULL; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 439 | ops->release(pipe, buf); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 440 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 441 | pipe->curbuf = curbuf; |
| 442 | pipe->nrbufs = --bufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | do_wakeup = 1; |
| 444 | } |
| 445 | total_len -= chars; |
| 446 | if (!total_len) |
| 447 | break; /* common path: read succeeded */ |
| 448 | } |
| 449 | if (bufs) /* More to do? */ |
| 450 | continue; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 451 | if (!pipe->writers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | break; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 453 | if (!pipe->waiting_writers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | /* syscall merging: Usually we must not sleep |
| 455 | * if O_NONBLOCK is set, or if we got some data. |
| 456 | * But if a writer sleeps in kernel space, then |
| 457 | * we can wait for that data without violating POSIX. |
| 458 | */ |
| 459 | if (ret) |
| 460 | break; |
| 461 | if (filp->f_flags & O_NONBLOCK) { |
| 462 | ret = -EAGAIN; |
| 463 | break; |
| 464 | } |
| 465 | } |
| 466 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 467 | if (!ret) |
| 468 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | break; |
| 470 | } |
| 471 | if (do_wakeup) { |
Linus Torvalds | 28e58ee | 2011-01-20 16:21:59 -0800 | [diff] [blame] | 472 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 473 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 475 | pipe_wait(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | } |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 477 | __pipe_unlock(pipe); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 478 | |
| 479 | /* Signal writers asynchronously that there is more room. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | if (do_wakeup) { |
Linus Torvalds | 28e58ee | 2011-01-20 16:21:59 -0800 | [diff] [blame] | 481 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 482 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | } |
| 484 | if (ret > 0) |
| 485 | file_accessed(filp); |
| 486 | return ret; |
| 487 | } |
| 488 | |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 489 | static inline int is_packetized(struct file *file) |
| 490 | { |
| 491 | return (file->f_flags & O_DIRECT) != 0; |
| 492 | } |
| 493 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 495 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
| 496 | unsigned long nr_segs, loff_t ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 498 | struct file *filp = iocb->ki_filp; |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 499 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | ssize_t ret; |
| 501 | int do_wakeup; |
| 502 | struct iovec *iov = (struct iovec *)_iov; |
| 503 | size_t total_len; |
| 504 | ssize_t chars; |
| 505 | |
| 506 | total_len = iov_length(iov, nr_segs); |
| 507 | /* Null write succeeds. */ |
| 508 | if (unlikely(total_len == 0)) |
| 509 | return 0; |
| 510 | |
| 511 | do_wakeup = 0; |
| 512 | ret = 0; |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 513 | __pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 515 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | send_sig(SIGPIPE, current, 0); |
| 517 | ret = -EPIPE; |
| 518 | goto out; |
| 519 | } |
| 520 | |
| 521 | /* We try to merge small writes */ |
| 522 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 523 | if (pipe->nrbufs && chars != 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 524 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 525 | (pipe->buffers - 1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 526 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 527 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | int offset = buf->offset + buf->len; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 529 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 531 | int error, atomic = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 532 | void *addr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 533 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 534 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 535 | if (error) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 536 | goto out; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 537 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 538 | iov_fault_in_pages_read(iov, chars); |
| 539 | redo1: |
| 540 | addr = ops->map(pipe, buf, atomic); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 541 | error = pipe_iov_copy_from_user(offset + addr, iov, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 542 | chars, atomic); |
| 543 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | ret = error; |
| 545 | do_wakeup = 1; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 546 | if (error) { |
| 547 | if (atomic) { |
| 548 | atomic = 0; |
| 549 | goto redo1; |
| 550 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 551 | goto out; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 552 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | buf->len += chars; |
| 554 | total_len -= chars; |
| 555 | ret = chars; |
| 556 | if (!total_len) |
| 557 | goto out; |
| 558 | } |
| 559 | } |
| 560 | |
| 561 | for (;;) { |
| 562 | int bufs; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 563 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 564 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | send_sig(SIGPIPE, current, 0); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 566 | if (!ret) |
| 567 | ret = -EPIPE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | break; |
| 569 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 570 | bufs = pipe->nrbufs; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 571 | if (bufs < pipe->buffers) { |
| 572 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 573 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
| 574 | struct page *page = pipe->tmp_page; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 575 | char *src; |
| 576 | int error, atomic = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | |
| 578 | if (!page) { |
| 579 | page = alloc_page(GFP_HIGHUSER); |
| 580 | if (unlikely(!page)) { |
| 581 | ret = ret ? : -ENOMEM; |
| 582 | break; |
| 583 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 584 | pipe->tmp_page = page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 586 | /* Always wake up, even if the copy fails. Otherwise |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | * we lock up (O_NONBLOCK-)readers that sleep due to |
| 588 | * syscall merging. |
| 589 | * FIXME! Is this really true? |
| 590 | */ |
| 591 | do_wakeup = 1; |
| 592 | chars = PAGE_SIZE; |
| 593 | if (chars > total_len) |
| 594 | chars = total_len; |
| 595 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 596 | iov_fault_in_pages_read(iov, chars); |
| 597 | redo2: |
| 598 | if (atomic) |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 599 | src = kmap_atomic(page); |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 600 | else |
| 601 | src = kmap(page); |
| 602 | |
| 603 | error = pipe_iov_copy_from_user(src, iov, chars, |
| 604 | atomic); |
| 605 | if (atomic) |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 606 | kunmap_atomic(src); |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 607 | else |
| 608 | kunmap(page); |
| 609 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 611 | if (atomic) { |
| 612 | atomic = 0; |
| 613 | goto redo2; |
| 614 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 615 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 616 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | break; |
| 618 | } |
| 619 | ret += chars; |
| 620 | |
| 621 | /* Insert it into the buffer array */ |
| 622 | buf->page = page; |
| 623 | buf->ops = &anon_pipe_buf_ops; |
| 624 | buf->offset = 0; |
| 625 | buf->len = chars; |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 626 | buf->flags = 0; |
| 627 | if (is_packetized(filp)) { |
| 628 | buf->ops = &packet_pipe_buf_ops; |
| 629 | buf->flags = PIPE_BUF_FLAG_PACKET; |
| 630 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 631 | pipe->nrbufs = ++bufs; |
| 632 | pipe->tmp_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | |
| 634 | total_len -= chars; |
| 635 | if (!total_len) |
| 636 | break; |
| 637 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 638 | if (bufs < pipe->buffers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | continue; |
| 640 | if (filp->f_flags & O_NONBLOCK) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 641 | if (!ret) |
| 642 | ret = -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | break; |
| 644 | } |
| 645 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 646 | if (!ret) |
| 647 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | break; |
| 649 | } |
| 650 | if (do_wakeup) { |
Linus Torvalds | 28e58ee | 2011-01-20 16:21:59 -0800 | [diff] [blame] | 651 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 652 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | do_wakeup = 0; |
| 654 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 655 | pipe->waiting_writers++; |
| 656 | pipe_wait(pipe); |
| 657 | pipe->waiting_writers--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | } |
| 659 | out: |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 660 | __pipe_unlock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | if (do_wakeup) { |
Linus Torvalds | 28e58ee | 2011-01-20 16:21:59 -0800 | [diff] [blame] | 662 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 663 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | } |
Josef Bacik | c3b2da3 | 2012-03-26 09:59:21 -0400 | [diff] [blame] | 665 | if (ret > 0) { |
| 666 | int err = file_update_time(filp); |
| 667 | if (err) |
| 668 | ret = err; |
| 669 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | return ret; |
| 671 | } |
| 672 | |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 673 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 674 | { |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 675 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 676 | int count, buf, nrbufs; |
| 677 | |
| 678 | switch (cmd) { |
| 679 | case FIONREAD: |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 680 | __pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | count = 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 682 | buf = pipe->curbuf; |
| 683 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | while (--nrbufs >= 0) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 685 | count += pipe->bufs[buf].len; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 686 | buf = (buf+1) & (pipe->buffers - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | } |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 688 | __pipe_unlock(pipe); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 689 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | return put_user(count, (int __user *)arg); |
| 691 | default: |
Will Deacon | 46ce341 | 2012-05-25 11:39:13 +0100 | [diff] [blame] | 692 | return -ENOIOCTLCMD; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | } |
| 694 | } |
| 695 | |
| 696 | /* No kernel lock held - fine */ |
| 697 | static unsigned int |
| 698 | pipe_poll(struct file *filp, poll_table *wait) |
| 699 | { |
| 700 | unsigned int mask; |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 701 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | int nrbufs; |
| 703 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 704 | poll_wait(filp, &pipe->wait, wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | |
| 706 | /* Reading only -- no need for acquiring the semaphore. */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 707 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | mask = 0; |
| 709 | if (filp->f_mode & FMODE_READ) { |
| 710 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 711 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | mask |= POLLHUP; |
| 713 | } |
| 714 | |
| 715 | if (filp->f_mode & FMODE_WRITE) { |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 716 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 717 | /* |
| 718 | * Most Unices do not set POLLERR for FIFOs but on Linux they |
| 719 | * behave exactly like pipes for poll(). |
| 720 | */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 721 | if (!pipe->readers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 722 | mask |= POLLERR; |
| 723 | } |
| 724 | |
| 725 | return mask; |
| 726 | } |
| 727 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | static int |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 729 | pipe_release(struct inode *inode, struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 730 | { |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 731 | struct pipe_inode_info *pipe = inode->i_pipe; |
| 732 | int kill = 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 733 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 734 | __pipe_lock(pipe); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 735 | if (file->f_mode & FMODE_READ) |
| 736 | pipe->readers--; |
| 737 | if (file->f_mode & FMODE_WRITE) |
| 738 | pipe->writers--; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 739 | |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 740 | if (pipe->readers || pipe->writers) { |
Linus Torvalds | 28e58ee | 2011-01-20 16:21:59 -0800 | [diff] [blame] | 741 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 742 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 743 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | } |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 745 | spin_lock(&inode->i_lock); |
| 746 | if (!--pipe->files) { |
| 747 | inode->i_pipe = NULL; |
| 748 | kill = 1; |
| 749 | } |
| 750 | spin_unlock(&inode->i_lock); |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 751 | __pipe_unlock(pipe); |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 752 | |
| 753 | if (kill) |
| 754 | __free_pipe_info(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | |
| 756 | return 0; |
| 757 | } |
| 758 | |
| 759 | static int |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 760 | pipe_fasync(int fd, struct file *filp, int on) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 761 | { |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 762 | struct pipe_inode_info *pipe = filp->private_data; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 763 | int retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 765 | __pipe_lock(pipe); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 766 | if (filp->f_mode & FMODE_READ) |
| 767 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
| 768 | if ((filp->f_mode & FMODE_WRITE) && retval >= 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 769 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 770 | if (retval < 0 && (filp->f_mode & FMODE_READ)) |
| 771 | /* this can happen only if on == T */ |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 772 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
| 773 | } |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 774 | __pipe_unlock(pipe); |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 775 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | } |
| 777 | |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame^] | 778 | struct pipe_inode_info *alloc_pipe_info(void) |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 779 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 780 | struct pipe_inode_info *pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 781 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 782 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
| 783 | if (pipe) { |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 784 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
| 785 | if (pipe->bufs) { |
| 786 | init_waitqueue_head(&pipe->wait); |
| 787 | pipe->r_counter = pipe->w_counter = 1; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 788 | pipe->buffers = PIPE_DEF_BUFFERS; |
Al Viro | 72b0d9a | 2013-03-21 02:32:24 -0400 | [diff] [blame] | 789 | mutex_init(&pipe->mutex); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 790 | return pipe; |
| 791 | } |
| 792 | kfree(pipe); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 793 | } |
| 794 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 795 | return NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 796 | } |
| 797 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 798 | void __free_pipe_info(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | { |
| 800 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 802 | for (i = 0; i < pipe->buffers; i++) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 803 | struct pipe_buffer *buf = pipe->bufs + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 804 | if (buf->ops) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 805 | buf->ops->release(pipe, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 806 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 807 | if (pipe->tmp_page) |
| 808 | __free_page(pipe->tmp_page); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 809 | kfree(pipe->bufs); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 810 | kfree(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 811 | } |
| 812 | |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 813 | void free_pipe_info(struct inode *inode) |
| 814 | { |
| 815 | __free_pipe_info(inode->i_pipe); |
| 816 | inode->i_pipe = NULL; |
| 817 | } |
| 818 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 819 | static struct vfsmount *pipe_mnt __read_mostly; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 820 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 821 | /* |
| 822 | * pipefs_dname() is called from d_path(). |
| 823 | */ |
| 824 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) |
| 825 | { |
| 826 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", |
| 827 | dentry->d_inode->i_ino); |
| 828 | } |
| 829 | |
Al Viro | 3ba13d1 | 2009-02-20 06:02:22 +0000 | [diff] [blame] | 830 | static const struct dentry_operations pipefs_dentry_operations = { |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 831 | .d_dname = pipefs_dname, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 832 | }; |
| 833 | |
| 834 | static struct inode * get_pipe_inode(void) |
| 835 | { |
Eric Dumazet | a209dfc | 2011-07-26 11:36:34 +0200 | [diff] [blame] | 836 | struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 837 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 838 | |
| 839 | if (!inode) |
| 840 | goto fail_inode; |
| 841 | |
Christoph Hellwig | 85fe402 | 2010-10-23 11:19:54 -0400 | [diff] [blame] | 842 | inode->i_ino = get_next_ino(); |
| 843 | |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame^] | 844 | pipe = alloc_pipe_info(); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 845 | if (!pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | goto fail_iput; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 847 | |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 848 | inode->i_pipe = pipe; |
| 849 | pipe->files = 2; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 850 | pipe->readers = pipe->writers = 1; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 851 | inode->i_fop = &pipefifo_fops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | |
| 853 | /* |
| 854 | * Mark the inode dirty from the very beginning, |
| 855 | * that way it will never be moved to the dirty |
| 856 | * list because "mark_inode_dirty()" will think |
| 857 | * that it already _is_ on the dirty list. |
| 858 | */ |
| 859 | inode->i_state = I_DIRTY; |
| 860 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 861 | inode->i_uid = current_fsuid(); |
| 862 | inode->i_gid = current_fsgid(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 864 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 865 | return inode; |
| 866 | |
| 867 | fail_iput: |
| 868 | iput(inode); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 869 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | fail_inode: |
| 871 | return NULL; |
| 872 | } |
| 873 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 874 | int create_pipe_files(struct file **res, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | { |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 876 | int err; |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 877 | struct inode *inode = get_pipe_inode(); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 878 | struct file *f; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 879 | struct path path; |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 880 | static struct qstr name = { .name = "" }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 881 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | if (!inode) |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 883 | return -ENFILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 884 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 885 | err = -ENOMEM; |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 886 | path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name); |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 887 | if (!path.dentry) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 888 | goto err_inode; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 889 | path.mnt = mntget(pipe_mnt); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 890 | |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 891 | d_instantiate(path.dentry, inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 892 | |
| 893 | err = -ENFILE; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 894 | f = alloc_file(&path, FMODE_WRITE, &pipefifo_fops); |
Anatol Pomozov | 39b6525 | 2012-09-12 20:11:55 -0700 | [diff] [blame] | 895 | if (IS_ERR(f)) |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 896 | goto err_dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 897 | |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 898 | f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)); |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 899 | f->private_data = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 900 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 901 | res[0] = alloc_file(&path, FMODE_READ, &pipefifo_fops); |
Anatol Pomozov | 39b6525 | 2012-09-12 20:11:55 -0700 | [diff] [blame] | 902 | if (IS_ERR(res[0])) |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 903 | goto err_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 905 | path_get(&path); |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 906 | res[0]->private_data = inode->i_pipe; |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 907 | res[0]->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
| 908 | res[1] = f; |
| 909 | return 0; |
| 910 | |
| 911 | err_file: |
| 912 | put_filp(f); |
| 913 | err_dentry: |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 914 | free_pipe_info(inode); |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 915 | path_put(&path); |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 916 | return err; |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 917 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 918 | err_inode: |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 919 | free_pipe_info(inode); |
| 920 | iput(inode); |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 921 | return err; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 922 | } |
| 923 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 924 | static int __do_pipe_flags(int *fd, struct file **files, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 925 | { |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 926 | int error; |
| 927 | int fdw, fdr; |
| 928 | |
Linus Torvalds | 9883035 | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 929 | if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT)) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 930 | return -EINVAL; |
| 931 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 932 | error = create_pipe_files(files, flags); |
| 933 | if (error) |
| 934 | return error; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 935 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 936 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 937 | if (error < 0) |
| 938 | goto err_read_pipe; |
| 939 | fdr = error; |
| 940 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 941 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 942 | if (error < 0) |
| 943 | goto err_fdr; |
| 944 | fdw = error; |
| 945 | |
Al Viro | 157cf64 | 2008-12-14 04:57:47 -0500 | [diff] [blame] | 946 | audit_fd_pair(fdr, fdw); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 947 | fd[0] = fdr; |
| 948 | fd[1] = fdw; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 949 | return 0; |
| 950 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 951 | err_fdr: |
| 952 | put_unused_fd(fdr); |
| 953 | err_read_pipe: |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 954 | fput(files[0]); |
| 955 | fput(files[1]); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 956 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | } |
| 958 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 959 | int do_pipe_flags(int *fd, int flags) |
| 960 | { |
| 961 | struct file *files[2]; |
| 962 | int error = __do_pipe_flags(fd, files, flags); |
| 963 | if (!error) { |
| 964 | fd_install(fd[0], files[0]); |
| 965 | fd_install(fd[1], files[1]); |
| 966 | } |
| 967 | return error; |
| 968 | } |
| 969 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | /* |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 971 | * sys_pipe() is the normal C calling standard for creating |
| 972 | * a pipe. It's not the way Unix traditionally does this, though. |
| 973 | */ |
Heiko Carstens | d4e8204 | 2009-01-14 14:14:34 +0100 | [diff] [blame] | 974 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 975 | { |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 976 | struct file *files[2]; |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 977 | int fd[2]; |
| 978 | int error; |
| 979 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 980 | error = __do_pipe_flags(fd, files, flags); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 981 | if (!error) { |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 982 | if (unlikely(copy_to_user(fildes, fd, sizeof(fd)))) { |
| 983 | fput(files[0]); |
| 984 | fput(files[1]); |
| 985 | put_unused_fd(fd[0]); |
| 986 | put_unused_fd(fd[1]); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 987 | error = -EFAULT; |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 988 | } else { |
| 989 | fd_install(fd[0], files[0]); |
| 990 | fd_install(fd[1], files[1]); |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 991 | } |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 992 | } |
| 993 | return error; |
| 994 | } |
| 995 | |
Heiko Carstens | 2b66421 | 2009-01-14 14:14:35 +0100 | [diff] [blame] | 996 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 997 | { |
| 998 | return sys_pipe2(fildes, 0); |
| 999 | } |
| 1000 | |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1001 | static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1002 | { |
| 1003 | int cur = *cnt; |
| 1004 | |
| 1005 | while (cur == *cnt) { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1006 | pipe_wait(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1007 | if (signal_pending(current)) |
| 1008 | break; |
| 1009 | } |
| 1010 | return cur == *cnt ? -ERESTARTSYS : 0; |
| 1011 | } |
| 1012 | |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1013 | static void wake_up_partner(struct pipe_inode_info *pipe) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1014 | { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1015 | wake_up_interruptible(&pipe->wait); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1016 | } |
| 1017 | |
| 1018 | static int fifo_open(struct inode *inode, struct file *filp) |
| 1019 | { |
| 1020 | struct pipe_inode_info *pipe; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1021 | bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC; |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1022 | int kill = 0; |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1023 | int ret; |
| 1024 | |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1025 | filp->f_version = 0; |
| 1026 | |
| 1027 | spin_lock(&inode->i_lock); |
| 1028 | if (inode->i_pipe) { |
| 1029 | pipe = inode->i_pipe; |
| 1030 | pipe->files++; |
| 1031 | spin_unlock(&inode->i_lock); |
| 1032 | } else { |
| 1033 | spin_unlock(&inode->i_lock); |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame^] | 1034 | pipe = alloc_pipe_info(); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1035 | if (!pipe) |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1036 | return -ENOMEM; |
| 1037 | pipe->files = 1; |
| 1038 | spin_lock(&inode->i_lock); |
| 1039 | if (unlikely(inode->i_pipe)) { |
| 1040 | inode->i_pipe->files++; |
| 1041 | spin_unlock(&inode->i_lock); |
| 1042 | __free_pipe_info(pipe); |
| 1043 | pipe = inode->i_pipe; |
| 1044 | } else { |
| 1045 | inode->i_pipe = pipe; |
| 1046 | spin_unlock(&inode->i_lock); |
| 1047 | } |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1048 | } |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 1049 | filp->private_data = pipe; |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1050 | /* OK, we have a pipe and it's pinned down */ |
| 1051 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1052 | __pipe_lock(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1053 | |
| 1054 | /* We can only do regular read/write on fifos */ |
| 1055 | filp->f_mode &= (FMODE_READ | FMODE_WRITE); |
| 1056 | |
| 1057 | switch (filp->f_mode) { |
| 1058 | case FMODE_READ: |
| 1059 | /* |
| 1060 | * O_RDONLY |
| 1061 | * POSIX.1 says that O_NONBLOCK means return with the FIFO |
| 1062 | * opened, even when there is no process writing the FIFO. |
| 1063 | */ |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1064 | pipe->r_counter++; |
| 1065 | if (pipe->readers++ == 0) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1066 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1067 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1068 | if (!is_pipe && !pipe->writers) { |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1069 | if ((filp->f_flags & O_NONBLOCK)) { |
| 1070 | /* suppress POLLHUP until we have |
| 1071 | * seen a writer */ |
| 1072 | filp->f_version = pipe->w_counter; |
| 1073 | } else { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1074 | if (wait_for_partner(pipe, &pipe->w_counter)) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1075 | goto err_rd; |
| 1076 | } |
| 1077 | } |
| 1078 | break; |
| 1079 | |
| 1080 | case FMODE_WRITE: |
| 1081 | /* |
| 1082 | * O_WRONLY |
| 1083 | * POSIX.1 says that O_NONBLOCK means return -1 with |
| 1084 | * errno=ENXIO when there is no process reading the FIFO. |
| 1085 | */ |
| 1086 | ret = -ENXIO; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1087 | if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1088 | goto err; |
| 1089 | |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1090 | pipe->w_counter++; |
| 1091 | if (!pipe->writers++) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1092 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1093 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1094 | if (!is_pipe && !pipe->readers) { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1095 | if (wait_for_partner(pipe, &pipe->r_counter)) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1096 | goto err_wr; |
| 1097 | } |
| 1098 | break; |
| 1099 | |
| 1100 | case FMODE_READ | FMODE_WRITE: |
| 1101 | /* |
| 1102 | * O_RDWR |
| 1103 | * POSIX.1 leaves this case "undefined" when O_NONBLOCK is set. |
| 1104 | * This implementation will NEVER block on a O_RDWR open, since |
| 1105 | * the process can at least talk to itself. |
| 1106 | */ |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1107 | |
| 1108 | pipe->readers++; |
| 1109 | pipe->writers++; |
| 1110 | pipe->r_counter++; |
| 1111 | pipe->w_counter++; |
| 1112 | if (pipe->readers == 1 || pipe->writers == 1) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1113 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1114 | break; |
| 1115 | |
| 1116 | default: |
| 1117 | ret = -EINVAL; |
| 1118 | goto err; |
| 1119 | } |
| 1120 | |
| 1121 | /* Ok! */ |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1122 | __pipe_unlock(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1123 | return 0; |
| 1124 | |
| 1125 | err_rd: |
| 1126 | if (!--pipe->readers) |
| 1127 | wake_up_interruptible(&pipe->wait); |
| 1128 | ret = -ERESTARTSYS; |
| 1129 | goto err; |
| 1130 | |
| 1131 | err_wr: |
| 1132 | if (!--pipe->writers) |
| 1133 | wake_up_interruptible(&pipe->wait); |
| 1134 | ret = -ERESTARTSYS; |
| 1135 | goto err; |
| 1136 | |
| 1137 | err: |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1138 | spin_lock(&inode->i_lock); |
| 1139 | if (!--pipe->files) { |
| 1140 | inode->i_pipe = NULL; |
| 1141 | kill = 1; |
| 1142 | } |
| 1143 | spin_unlock(&inode->i_lock); |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1144 | __pipe_unlock(pipe); |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1145 | if (kill) |
| 1146 | __free_pipe_info(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1147 | return ret; |
| 1148 | } |
| 1149 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1150 | const struct file_operations pipefifo_fops = { |
| 1151 | .open = fifo_open, |
| 1152 | .llseek = no_llseek, |
| 1153 | .read = do_sync_read, |
| 1154 | .aio_read = pipe_read, |
| 1155 | .write = do_sync_write, |
| 1156 | .aio_write = pipe_write, |
| 1157 | .poll = pipe_poll, |
| 1158 | .unlocked_ioctl = pipe_ioctl, |
| 1159 | .release = pipe_release, |
| 1160 | .fasync = pipe_fasync, |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1161 | }; |
| 1162 | |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1163 | /* |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1164 | * Allocate a new array of pipe buffers and copy the info over. Returns the |
| 1165 | * pipe size if successful, or return -ERROR on error. |
| 1166 | */ |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1167 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1168 | { |
| 1169 | struct pipe_buffer *bufs; |
| 1170 | |
| 1171 | /* |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1172 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't |
| 1173 | * expect a lot of shrink+grow operations, just free and allocate |
| 1174 | * again like we would do for growing. If the pipe currently |
| 1175 | * contains more buffers than arg, then return busy. |
| 1176 | */ |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1177 | if (nr_pages < pipe->nrbufs) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1178 | return -EBUSY; |
| 1179 | |
Sasha Levin | 2ccd4f4 | 2012-01-12 17:17:40 -0800 | [diff] [blame] | 1180 | bufs = kcalloc(nr_pages, sizeof(*bufs), GFP_KERNEL | __GFP_NOWARN); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1181 | if (unlikely(!bufs)) |
| 1182 | return -ENOMEM; |
| 1183 | |
| 1184 | /* |
| 1185 | * The pipe array wraps around, so just start the new one at zero |
| 1186 | * and adjust the indexes. |
| 1187 | */ |
| 1188 | if (pipe->nrbufs) { |
Miklos Szeredi | 1d862f4 | 2010-06-08 16:28:45 +0200 | [diff] [blame] | 1189 | unsigned int tail; |
| 1190 | unsigned int head; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1191 | |
Miklos Szeredi | 1d862f4 | 2010-06-08 16:28:45 +0200 | [diff] [blame] | 1192 | tail = pipe->curbuf + pipe->nrbufs; |
| 1193 | if (tail < pipe->buffers) |
| 1194 | tail = 0; |
| 1195 | else |
| 1196 | tail &= (pipe->buffers - 1); |
| 1197 | |
| 1198 | head = pipe->nrbufs - tail; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1199 | if (head) |
| 1200 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); |
| 1201 | if (tail) |
Miklos Szeredi | 1d862f4 | 2010-06-08 16:28:45 +0200 | [diff] [blame] | 1202 | memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1203 | } |
| 1204 | |
| 1205 | pipe->curbuf = 0; |
| 1206 | kfree(pipe->bufs); |
| 1207 | pipe->bufs = bufs; |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1208 | pipe->buffers = nr_pages; |
| 1209 | return nr_pages * PAGE_SIZE; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1210 | } |
| 1211 | |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1212 | /* |
| 1213 | * Currently we rely on the pipe array holding a power-of-2 number |
| 1214 | * of pages. |
| 1215 | */ |
| 1216 | static inline unsigned int round_pipe_size(unsigned int size) |
| 1217 | { |
| 1218 | unsigned long nr_pages; |
| 1219 | |
| 1220 | nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1221 | return roundup_pow_of_two(nr_pages) << PAGE_SHIFT; |
| 1222 | } |
| 1223 | |
| 1224 | /* |
| 1225 | * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax |
| 1226 | * will return an error. |
| 1227 | */ |
| 1228 | int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, |
| 1229 | size_t *lenp, loff_t *ppos) |
| 1230 | { |
| 1231 | int ret; |
| 1232 | |
| 1233 | ret = proc_dointvec_minmax(table, write, buf, lenp, ppos); |
| 1234 | if (ret < 0 || !write) |
| 1235 | return ret; |
| 1236 | |
| 1237 | pipe_max_size = round_pipe_size(pipe_max_size); |
| 1238 | return ret; |
| 1239 | } |
| 1240 | |
Linus Torvalds | 7208364 | 2010-11-28 16:27:19 -0800 | [diff] [blame] | 1241 | /* |
| 1242 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same |
| 1243 | * location, so checking ->i_pipe is not enough to verify that this is a |
| 1244 | * pipe. |
| 1245 | */ |
| 1246 | struct pipe_inode_info *get_pipe_info(struct file *file) |
| 1247 | { |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 1248 | return file->f_op == &pipefifo_fops ? file->private_data : NULL; |
Linus Torvalds | 7208364 | 2010-11-28 16:27:19 -0800 | [diff] [blame] | 1249 | } |
| 1250 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1251 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
| 1252 | { |
| 1253 | struct pipe_inode_info *pipe; |
| 1254 | long ret; |
| 1255 | |
Linus Torvalds | c66fb34 | 2010-11-28 14:09:57 -0800 | [diff] [blame] | 1256 | pipe = get_pipe_info(file); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1257 | if (!pipe) |
| 1258 | return -EBADF; |
| 1259 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1260 | __pipe_lock(pipe); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1261 | |
| 1262 | switch (cmd) { |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1263 | case F_SETPIPE_SZ: { |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1264 | unsigned int size, nr_pages; |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1265 | |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1266 | size = round_pipe_size(arg); |
| 1267 | nr_pages = size >> PAGE_SHIFT; |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1268 | |
Miklos Szeredi | 6db40cf | 2010-06-09 09:27:57 +0200 | [diff] [blame] | 1269 | ret = -EINVAL; |
| 1270 | if (!nr_pages) |
| 1271 | goto out; |
| 1272 | |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1273 | if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { |
Jens Axboe | b4ca761 | 2010-06-01 12:42:12 +0200 | [diff] [blame] | 1274 | ret = -EPERM; |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame] | 1275 | goto out; |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame] | 1276 | } |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1277 | ret = pipe_set_size(pipe, nr_pages); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1278 | break; |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1279 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1280 | case F_GETPIPE_SZ: |
Jens Axboe | b9598db | 2010-05-24 19:34:43 +0200 | [diff] [blame] | 1281 | ret = pipe->buffers * PAGE_SIZE; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1282 | break; |
| 1283 | default: |
| 1284 | ret = -EINVAL; |
| 1285 | break; |
| 1286 | } |
| 1287 | |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame] | 1288 | out: |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1289 | __pipe_unlock(pipe); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1290 | return ret; |
| 1291 | } |
| 1292 | |
Nick Piggin | ff0c7d1 | 2011-01-07 17:49:50 +1100 | [diff] [blame] | 1293 | static const struct super_operations pipefs_ops = { |
| 1294 | .destroy_inode = free_inode_nonrcu, |
Pavel Emelyanov | d70ef97 | 2011-10-31 17:10:04 -0700 | [diff] [blame] | 1295 | .statfs = simple_statfs, |
Nick Piggin | ff0c7d1 | 2011-01-07 17:49:50 +1100 | [diff] [blame] | 1296 | }; |
| 1297 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1298 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | * pipefs should _never_ be mounted by userland - too much of security hassle, |
| 1300 | * no real gain from having the whole whorehouse mounted. So we don't need |
| 1301 | * any operations on the root directory. However, we need a non-trivial |
| 1302 | * d_name - pipe: will go nicely and kill the special-casing in procfs. |
| 1303 | */ |
Al Viro | 51139ad | 2010-07-25 23:47:46 +0400 | [diff] [blame] | 1304 | static struct dentry *pipefs_mount(struct file_system_type *fs_type, |
| 1305 | int flags, const char *dev_name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1306 | { |
Al Viro | c74a1cb | 2011-01-12 16:59:34 -0500 | [diff] [blame] | 1307 | return mount_pseudo(fs_type, "pipe:", &pipefs_ops, |
| 1308 | &pipefs_dentry_operations, PIPEFS_MAGIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1309 | } |
| 1310 | |
| 1311 | static struct file_system_type pipe_fs_type = { |
| 1312 | .name = "pipefs", |
Al Viro | 51139ad | 2010-07-25 23:47:46 +0400 | [diff] [blame] | 1313 | .mount = pipefs_mount, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1314 | .kill_sb = kill_anon_super, |
| 1315 | }; |
| 1316 | |
| 1317 | static int __init init_pipe_fs(void) |
| 1318 | { |
| 1319 | int err = register_filesystem(&pipe_fs_type); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1320 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1321 | if (!err) { |
| 1322 | pipe_mnt = kern_mount(&pipe_fs_type); |
| 1323 | if (IS_ERR(pipe_mnt)) { |
| 1324 | err = PTR_ERR(pipe_mnt); |
| 1325 | unregister_filesystem(&pipe_fs_type); |
| 1326 | } |
| 1327 | } |
| 1328 | return err; |
| 1329 | } |
| 1330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | fs_initcall(init_pipe_fs); |