Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Public API and common code for kernel->userspace relay file support. |
| 3 | * |
| 4 | * See Documentation/filesystems/relayfs.txt for an overview of relayfs. |
| 5 | * |
| 6 | * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp |
| 7 | * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com) |
| 8 | * |
| 9 | * Moved to kernel/relay.c by Paul Mundt, 2006. |
| 10 | * |
| 11 | * This file is released under the GPL. |
| 12 | */ |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/stddef.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/string.h> |
| 18 | #include <linux/relay.h> |
| 19 | #include <linux/vmalloc.h> |
| 20 | #include <linux/mm.h> |
| 21 | |
| 22 | /* |
| 23 | * close() vm_op implementation for relay file mapping. |
| 24 | */ |
| 25 | static void relay_file_mmap_close(struct vm_area_struct *vma) |
| 26 | { |
| 27 | struct rchan_buf *buf = vma->vm_private_data; |
| 28 | buf->chan->cb->buf_unmapped(buf, vma->vm_file); |
| 29 | } |
| 30 | |
| 31 | /* |
| 32 | * nopage() vm_op implementation for relay file mapping. |
| 33 | */ |
| 34 | static struct page *relay_buf_nopage(struct vm_area_struct *vma, |
| 35 | unsigned long address, |
| 36 | int *type) |
| 37 | { |
| 38 | struct page *page; |
| 39 | struct rchan_buf *buf = vma->vm_private_data; |
| 40 | unsigned long offset = address - vma->vm_start; |
| 41 | |
| 42 | if (address > vma->vm_end) |
| 43 | return NOPAGE_SIGBUS; /* Disallow mremap */ |
| 44 | if (!buf) |
| 45 | return NOPAGE_OOM; |
| 46 | |
| 47 | page = vmalloc_to_page(buf->start + offset); |
| 48 | if (!page) |
| 49 | return NOPAGE_OOM; |
| 50 | get_page(page); |
| 51 | |
| 52 | if (type) |
| 53 | *type = VM_FAULT_MINOR; |
| 54 | |
| 55 | return page; |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * vm_ops for relay file mappings. |
| 60 | */ |
| 61 | static struct vm_operations_struct relay_file_mmap_ops = { |
| 62 | .nopage = relay_buf_nopage, |
| 63 | .close = relay_file_mmap_close, |
| 64 | }; |
| 65 | |
| 66 | /** |
| 67 | * relay_mmap_buf: - mmap channel buffer to process address space |
| 68 | * @buf: relay channel buffer |
| 69 | * @vma: vm_area_struct describing memory to be mapped |
| 70 | * |
| 71 | * Returns 0 if ok, negative on error |
| 72 | * |
| 73 | * Caller should already have grabbed mmap_sem. |
| 74 | */ |
| 75 | int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma) |
| 76 | { |
| 77 | unsigned long length = vma->vm_end - vma->vm_start; |
| 78 | struct file *filp = vma->vm_file; |
| 79 | |
| 80 | if (!buf) |
| 81 | return -EBADF; |
| 82 | |
| 83 | if (length != (unsigned long)buf->chan->alloc_size) |
| 84 | return -EINVAL; |
| 85 | |
| 86 | vma->vm_ops = &relay_file_mmap_ops; |
| 87 | vma->vm_private_data = buf; |
| 88 | buf->chan->cb->buf_mapped(buf, filp); |
| 89 | |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * relay_alloc_buf - allocate a channel buffer |
| 95 | * @buf: the buffer struct |
| 96 | * @size: total size of the buffer |
| 97 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 98 | * Returns a pointer to the resulting buffer, %NULL if unsuccessful. The |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 99 | * passed in size will get page aligned, if it isn't already. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 100 | */ |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 101 | static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 102 | { |
| 103 | void *mem; |
| 104 | unsigned int i, j, n_pages; |
| 105 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 106 | *size = PAGE_ALIGN(*size); |
| 107 | n_pages = *size >> PAGE_SHIFT; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 108 | |
| 109 | buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL); |
| 110 | if (!buf->page_array) |
| 111 | return NULL; |
| 112 | |
| 113 | for (i = 0; i < n_pages; i++) { |
| 114 | buf->page_array[i] = alloc_page(GFP_KERNEL); |
| 115 | if (unlikely(!buf->page_array[i])) |
| 116 | goto depopulate; |
| 117 | } |
| 118 | mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL); |
| 119 | if (!mem) |
| 120 | goto depopulate; |
| 121 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 122 | memset(mem, 0, *size); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 123 | buf->page_count = n_pages; |
| 124 | return mem; |
| 125 | |
| 126 | depopulate: |
| 127 | for (j = 0; j < i; j++) |
| 128 | __free_page(buf->page_array[j]); |
| 129 | kfree(buf->page_array); |
| 130 | return NULL; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * relay_create_buf - allocate and initialize a channel buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 135 | * @chan: the relay channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 136 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 137 | * Returns channel buffer if successful, %NULL otherwise. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 138 | */ |
| 139 | struct rchan_buf *relay_create_buf(struct rchan *chan) |
| 140 | { |
| 141 | struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL); |
| 142 | if (!buf) |
| 143 | return NULL; |
| 144 | |
| 145 | buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL); |
| 146 | if (!buf->padding) |
| 147 | goto free_buf; |
| 148 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 149 | buf->start = relay_alloc_buf(buf, &chan->alloc_size); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 150 | if (!buf->start) |
| 151 | goto free_buf; |
| 152 | |
| 153 | buf->chan = chan; |
| 154 | kref_get(&buf->chan->kref); |
| 155 | return buf; |
| 156 | |
| 157 | free_buf: |
| 158 | kfree(buf->padding); |
| 159 | kfree(buf); |
| 160 | return NULL; |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * relay_destroy_channel - free the channel struct |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 165 | * @kref: target kernel reference that contains the relay channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 166 | * |
| 167 | * Should only be called from kref_put(). |
| 168 | */ |
| 169 | void relay_destroy_channel(struct kref *kref) |
| 170 | { |
| 171 | struct rchan *chan = container_of(kref, struct rchan, kref); |
| 172 | kfree(chan); |
| 173 | } |
| 174 | |
| 175 | /** |
| 176 | * relay_destroy_buf - destroy an rchan_buf struct and associated buffer |
| 177 | * @buf: the buffer struct |
| 178 | */ |
| 179 | void relay_destroy_buf(struct rchan_buf *buf) |
| 180 | { |
| 181 | struct rchan *chan = buf->chan; |
| 182 | unsigned int i; |
| 183 | |
| 184 | if (likely(buf->start)) { |
| 185 | vunmap(buf->start); |
| 186 | for (i = 0; i < buf->page_count; i++) |
| 187 | __free_page(buf->page_array[i]); |
| 188 | kfree(buf->page_array); |
| 189 | } |
| 190 | kfree(buf->padding); |
| 191 | kfree(buf); |
| 192 | kref_put(&chan->kref, relay_destroy_channel); |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * relay_remove_buf - remove a channel buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 197 | * @kref: target kernel reference that contains the relay buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 198 | * |
| 199 | * Removes the file from the fileystem, which also frees the |
| 200 | * rchan_buf_struct and the channel buffer. Should only be called from |
| 201 | * kref_put(). |
| 202 | */ |
| 203 | void relay_remove_buf(struct kref *kref) |
| 204 | { |
| 205 | struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); |
| 206 | buf->chan->cb->remove_buf_file(buf->dentry); |
| 207 | relay_destroy_buf(buf); |
| 208 | } |
| 209 | |
| 210 | /** |
| 211 | * relay_buf_empty - boolean, is the channel buffer empty? |
| 212 | * @buf: channel buffer |
| 213 | * |
| 214 | * Returns 1 if the buffer is empty, 0 otherwise. |
| 215 | */ |
| 216 | int relay_buf_empty(struct rchan_buf *buf) |
| 217 | { |
| 218 | return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1; |
| 219 | } |
| 220 | EXPORT_SYMBOL_GPL(relay_buf_empty); |
| 221 | |
| 222 | /** |
| 223 | * relay_buf_full - boolean, is the channel buffer full? |
| 224 | * @buf: channel buffer |
| 225 | * |
| 226 | * Returns 1 if the buffer is full, 0 otherwise. |
| 227 | */ |
| 228 | int relay_buf_full(struct rchan_buf *buf) |
| 229 | { |
| 230 | size_t ready = buf->subbufs_produced - buf->subbufs_consumed; |
| 231 | return (ready >= buf->chan->n_subbufs) ? 1 : 0; |
| 232 | } |
| 233 | EXPORT_SYMBOL_GPL(relay_buf_full); |
| 234 | |
| 235 | /* |
| 236 | * High-level relay kernel API and associated functions. |
| 237 | */ |
| 238 | |
| 239 | /* |
| 240 | * rchan_callback implementations defining default channel behavior. Used |
| 241 | * in place of corresponding NULL values in client callback struct. |
| 242 | */ |
| 243 | |
| 244 | /* |
| 245 | * subbuf_start() default callback. Does nothing. |
| 246 | */ |
| 247 | static int subbuf_start_default_callback (struct rchan_buf *buf, |
| 248 | void *subbuf, |
| 249 | void *prev_subbuf, |
| 250 | size_t prev_padding) |
| 251 | { |
| 252 | if (relay_buf_full(buf)) |
| 253 | return 0; |
| 254 | |
| 255 | return 1; |
| 256 | } |
| 257 | |
| 258 | /* |
| 259 | * buf_mapped() default callback. Does nothing. |
| 260 | */ |
| 261 | static void buf_mapped_default_callback(struct rchan_buf *buf, |
| 262 | struct file *filp) |
| 263 | { |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * buf_unmapped() default callback. Does nothing. |
| 268 | */ |
| 269 | static void buf_unmapped_default_callback(struct rchan_buf *buf, |
| 270 | struct file *filp) |
| 271 | { |
| 272 | } |
| 273 | |
| 274 | /* |
| 275 | * create_buf_file_create() default callback. Does nothing. |
| 276 | */ |
| 277 | static struct dentry *create_buf_file_default_callback(const char *filename, |
| 278 | struct dentry *parent, |
| 279 | int mode, |
| 280 | struct rchan_buf *buf, |
| 281 | int *is_global) |
| 282 | { |
| 283 | return NULL; |
| 284 | } |
| 285 | |
| 286 | /* |
| 287 | * remove_buf_file() default callback. Does nothing. |
| 288 | */ |
| 289 | static int remove_buf_file_default_callback(struct dentry *dentry) |
| 290 | { |
| 291 | return -EINVAL; |
| 292 | } |
| 293 | |
| 294 | /* relay channel default callbacks */ |
| 295 | static struct rchan_callbacks default_channel_callbacks = { |
| 296 | .subbuf_start = subbuf_start_default_callback, |
| 297 | .buf_mapped = buf_mapped_default_callback, |
| 298 | .buf_unmapped = buf_unmapped_default_callback, |
| 299 | .create_buf_file = create_buf_file_default_callback, |
| 300 | .remove_buf_file = remove_buf_file_default_callback, |
| 301 | }; |
| 302 | |
| 303 | /** |
| 304 | * wakeup_readers - wake up readers waiting on a channel |
| 305 | * @private: the channel buffer |
| 306 | * |
| 307 | * This is the work function used to defer reader waking. The |
| 308 | * reason waking is deferred is that calling directly from write |
| 309 | * causes problems if you're writing from say the scheduler. |
| 310 | */ |
| 311 | static void wakeup_readers(void *private) |
| 312 | { |
| 313 | struct rchan_buf *buf = private; |
| 314 | wake_up_interruptible(&buf->read_wait); |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * __relay_reset - reset a channel buffer |
| 319 | * @buf: the channel buffer |
| 320 | * @init: 1 if this is a first-time initialization |
| 321 | * |
| 322 | * See relay_reset for description of effect. |
| 323 | */ |
| 324 | static inline void __relay_reset(struct rchan_buf *buf, unsigned int init) |
| 325 | { |
| 326 | size_t i; |
| 327 | |
| 328 | if (init) { |
| 329 | init_waitqueue_head(&buf->read_wait); |
| 330 | kref_init(&buf->kref); |
| 331 | INIT_WORK(&buf->wake_readers, NULL, NULL); |
| 332 | } else { |
| 333 | cancel_delayed_work(&buf->wake_readers); |
| 334 | flush_scheduled_work(); |
| 335 | } |
| 336 | |
| 337 | buf->subbufs_produced = 0; |
| 338 | buf->subbufs_consumed = 0; |
| 339 | buf->bytes_consumed = 0; |
| 340 | buf->finalized = 0; |
| 341 | buf->data = buf->start; |
| 342 | buf->offset = 0; |
| 343 | |
| 344 | for (i = 0; i < buf->chan->n_subbufs; i++) |
| 345 | buf->padding[i] = 0; |
| 346 | |
| 347 | buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0); |
| 348 | } |
| 349 | |
| 350 | /** |
| 351 | * relay_reset - reset the channel |
| 352 | * @chan: the channel |
| 353 | * |
| 354 | * This has the effect of erasing all data from all channel buffers |
| 355 | * and restarting the channel in its initial state. The buffers |
| 356 | * are not freed, so any mappings are still in effect. |
| 357 | * |
| 358 | * NOTE: Care should be taken that the channel isn't actually |
| 359 | * being used by anything when this call is made. |
| 360 | */ |
| 361 | void relay_reset(struct rchan *chan) |
| 362 | { |
| 363 | unsigned int i; |
| 364 | struct rchan_buf *prev = NULL; |
| 365 | |
| 366 | if (!chan) |
| 367 | return; |
| 368 | |
| 369 | for (i = 0; i < NR_CPUS; i++) { |
| 370 | if (!chan->buf[i] || chan->buf[i] == prev) |
| 371 | break; |
| 372 | __relay_reset(chan->buf[i], 0); |
| 373 | prev = chan->buf[i]; |
| 374 | } |
| 375 | } |
| 376 | EXPORT_SYMBOL_GPL(relay_reset); |
| 377 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 378 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 379 | * relay_open_buf - create a new relay channel buffer |
| 380 | * |
| 381 | * Internal - used by relay_open(). |
| 382 | */ |
| 383 | static struct rchan_buf *relay_open_buf(struct rchan *chan, |
| 384 | const char *filename, |
| 385 | struct dentry *parent, |
| 386 | int *is_global) |
| 387 | { |
| 388 | struct rchan_buf *buf; |
| 389 | struct dentry *dentry; |
| 390 | |
| 391 | if (*is_global) |
| 392 | return chan->buf[0]; |
| 393 | |
| 394 | buf = relay_create_buf(chan); |
| 395 | if (!buf) |
| 396 | return NULL; |
| 397 | |
| 398 | /* Create file in fs */ |
| 399 | dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR, |
| 400 | buf, is_global); |
| 401 | if (!dentry) { |
| 402 | relay_destroy_buf(buf); |
| 403 | return NULL; |
| 404 | } |
| 405 | |
| 406 | buf->dentry = dentry; |
| 407 | __relay_reset(buf, 1); |
| 408 | |
| 409 | return buf; |
| 410 | } |
| 411 | |
| 412 | /** |
| 413 | * relay_close_buf - close a channel buffer |
| 414 | * @buf: channel buffer |
| 415 | * |
| 416 | * Marks the buffer finalized and restores the default callbacks. |
| 417 | * The channel buffer and channel buffer data structure are then freed |
| 418 | * automatically when the last reference is given up. |
| 419 | */ |
| 420 | static inline void relay_close_buf(struct rchan_buf *buf) |
| 421 | { |
| 422 | buf->finalized = 1; |
| 423 | cancel_delayed_work(&buf->wake_readers); |
| 424 | flush_scheduled_work(); |
| 425 | kref_put(&buf->kref, relay_remove_buf); |
| 426 | } |
| 427 | |
| 428 | static inline void setup_callbacks(struct rchan *chan, |
| 429 | struct rchan_callbacks *cb) |
| 430 | { |
| 431 | if (!cb) { |
| 432 | chan->cb = &default_channel_callbacks; |
| 433 | return; |
| 434 | } |
| 435 | |
| 436 | if (!cb->subbuf_start) |
| 437 | cb->subbuf_start = subbuf_start_default_callback; |
| 438 | if (!cb->buf_mapped) |
| 439 | cb->buf_mapped = buf_mapped_default_callback; |
| 440 | if (!cb->buf_unmapped) |
| 441 | cb->buf_unmapped = buf_unmapped_default_callback; |
| 442 | if (!cb->create_buf_file) |
| 443 | cb->create_buf_file = create_buf_file_default_callback; |
| 444 | if (!cb->remove_buf_file) |
| 445 | cb->remove_buf_file = remove_buf_file_default_callback; |
| 446 | chan->cb = cb; |
| 447 | } |
| 448 | |
| 449 | /** |
| 450 | * relay_open - create a new relay channel |
| 451 | * @base_filename: base name of files to create |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 452 | * @parent: dentry of parent directory, %NULL for root directory |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 453 | * @subbuf_size: size of sub-buffers |
| 454 | * @n_subbufs: number of sub-buffers |
| 455 | * @cb: client callback functions |
| 456 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 457 | * Returns channel pointer if successful, %NULL otherwise. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 458 | * |
| 459 | * Creates a channel buffer for each cpu using the sizes and |
| 460 | * attributes specified. The created channel buffer files |
| 461 | * will be named base_filename0...base_filenameN-1. File |
| 462 | * permissions will be S_IRUSR. |
| 463 | */ |
| 464 | struct rchan *relay_open(const char *base_filename, |
| 465 | struct dentry *parent, |
| 466 | size_t subbuf_size, |
| 467 | size_t n_subbufs, |
| 468 | struct rchan_callbacks *cb) |
| 469 | { |
| 470 | unsigned int i; |
| 471 | struct rchan *chan; |
| 472 | char *tmpname; |
| 473 | int is_global = 0; |
| 474 | |
| 475 | if (!base_filename) |
| 476 | return NULL; |
| 477 | |
| 478 | if (!(subbuf_size && n_subbufs)) |
| 479 | return NULL; |
| 480 | |
| 481 | chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL); |
| 482 | if (!chan) |
| 483 | return NULL; |
| 484 | |
| 485 | chan->version = RELAYFS_CHANNEL_VERSION; |
| 486 | chan->n_subbufs = n_subbufs; |
| 487 | chan->subbuf_size = subbuf_size; |
| 488 | chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); |
| 489 | setup_callbacks(chan, cb); |
| 490 | kref_init(&chan->kref); |
| 491 | |
| 492 | tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL); |
| 493 | if (!tmpname) |
| 494 | goto free_chan; |
| 495 | |
| 496 | for_each_online_cpu(i) { |
| 497 | sprintf(tmpname, "%s%d", base_filename, i); |
| 498 | chan->buf[i] = relay_open_buf(chan, tmpname, parent, |
| 499 | &is_global); |
| 500 | if (!chan->buf[i]) |
| 501 | goto free_bufs; |
| 502 | |
| 503 | chan->buf[i]->cpu = i; |
| 504 | } |
| 505 | |
| 506 | kfree(tmpname); |
| 507 | return chan; |
| 508 | |
| 509 | free_bufs: |
| 510 | for (i = 0; i < NR_CPUS; i++) { |
| 511 | if (!chan->buf[i]) |
| 512 | break; |
| 513 | relay_close_buf(chan->buf[i]); |
| 514 | if (is_global) |
| 515 | break; |
| 516 | } |
| 517 | kfree(tmpname); |
| 518 | |
| 519 | free_chan: |
| 520 | kref_put(&chan->kref, relay_destroy_channel); |
| 521 | return NULL; |
| 522 | } |
| 523 | EXPORT_SYMBOL_GPL(relay_open); |
| 524 | |
| 525 | /** |
| 526 | * relay_switch_subbuf - switch to a new sub-buffer |
| 527 | * @buf: channel buffer |
| 528 | * @length: size of current event |
| 529 | * |
| 530 | * Returns either the length passed in or 0 if full. |
| 531 | * |
| 532 | * Performs sub-buffer-switch tasks such as invoking callbacks, |
| 533 | * updating padding counts, waking up readers, etc. |
| 534 | */ |
| 535 | size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) |
| 536 | { |
| 537 | void *old, *new; |
| 538 | size_t old_subbuf, new_subbuf; |
| 539 | |
| 540 | if (unlikely(length > buf->chan->subbuf_size)) |
| 541 | goto toobig; |
| 542 | |
| 543 | if (buf->offset != buf->chan->subbuf_size + 1) { |
| 544 | buf->prev_padding = buf->chan->subbuf_size - buf->offset; |
| 545 | old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; |
| 546 | buf->padding[old_subbuf] = buf->prev_padding; |
| 547 | buf->subbufs_produced++; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 548 | buf->dentry->d_inode->i_size += buf->chan->subbuf_size - |
| 549 | buf->padding[old_subbuf]; |
| 550 | smp_mb(); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 551 | if (waitqueue_active(&buf->read_wait)) { |
| 552 | PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf); |
| 553 | schedule_delayed_work(&buf->wake_readers, 1); |
| 554 | } |
| 555 | } |
| 556 | |
| 557 | old = buf->data; |
| 558 | new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; |
| 559 | new = buf->start + new_subbuf * buf->chan->subbuf_size; |
| 560 | buf->offset = 0; |
| 561 | if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) { |
| 562 | buf->offset = buf->chan->subbuf_size + 1; |
| 563 | return 0; |
| 564 | } |
| 565 | buf->data = new; |
| 566 | buf->padding[new_subbuf] = 0; |
| 567 | |
| 568 | if (unlikely(length + buf->offset > buf->chan->subbuf_size)) |
| 569 | goto toobig; |
| 570 | |
| 571 | return length; |
| 572 | |
| 573 | toobig: |
| 574 | buf->chan->last_toobig = length; |
| 575 | return 0; |
| 576 | } |
| 577 | EXPORT_SYMBOL_GPL(relay_switch_subbuf); |
| 578 | |
| 579 | /** |
| 580 | * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count |
| 581 | * @chan: the channel |
| 582 | * @cpu: the cpu associated with the channel buffer to update |
| 583 | * @subbufs_consumed: number of sub-buffers to add to current buf's count |
| 584 | * |
| 585 | * Adds to the channel buffer's consumed sub-buffer count. |
| 586 | * subbufs_consumed should be the number of sub-buffers newly consumed, |
| 587 | * not the total consumed. |
| 588 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 589 | * NOTE: Kernel clients don't need to call this function if the channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 590 | * mode is 'overwrite'. |
| 591 | */ |
| 592 | void relay_subbufs_consumed(struct rchan *chan, |
| 593 | unsigned int cpu, |
| 594 | size_t subbufs_consumed) |
| 595 | { |
| 596 | struct rchan_buf *buf; |
| 597 | |
| 598 | if (!chan) |
| 599 | return; |
| 600 | |
| 601 | if (cpu >= NR_CPUS || !chan->buf[cpu]) |
| 602 | return; |
| 603 | |
| 604 | buf = chan->buf[cpu]; |
| 605 | buf->subbufs_consumed += subbufs_consumed; |
| 606 | if (buf->subbufs_consumed > buf->subbufs_produced) |
| 607 | buf->subbufs_consumed = buf->subbufs_produced; |
| 608 | } |
| 609 | EXPORT_SYMBOL_GPL(relay_subbufs_consumed); |
| 610 | |
| 611 | /** |
| 612 | * relay_close - close the channel |
| 613 | * @chan: the channel |
| 614 | * |
| 615 | * Closes all channel buffers and frees the channel. |
| 616 | */ |
| 617 | void relay_close(struct rchan *chan) |
| 618 | { |
| 619 | unsigned int i; |
| 620 | struct rchan_buf *prev = NULL; |
| 621 | |
| 622 | if (!chan) |
| 623 | return; |
| 624 | |
| 625 | for (i = 0; i < NR_CPUS; i++) { |
| 626 | if (!chan->buf[i] || chan->buf[i] == prev) |
| 627 | break; |
| 628 | relay_close_buf(chan->buf[i]); |
| 629 | prev = chan->buf[i]; |
| 630 | } |
| 631 | |
| 632 | if (chan->last_toobig) |
| 633 | printk(KERN_WARNING "relay: one or more items not logged " |
| 634 | "[item size (%Zd) > sub-buffer size (%Zd)]\n", |
| 635 | chan->last_toobig, chan->subbuf_size); |
| 636 | |
| 637 | kref_put(&chan->kref, relay_destroy_channel); |
| 638 | } |
| 639 | EXPORT_SYMBOL_GPL(relay_close); |
| 640 | |
| 641 | /** |
| 642 | * relay_flush - close the channel |
| 643 | * @chan: the channel |
| 644 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 645 | * Flushes all channel buffers, i.e. forces buffer switch. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 646 | */ |
| 647 | void relay_flush(struct rchan *chan) |
| 648 | { |
| 649 | unsigned int i; |
| 650 | struct rchan_buf *prev = NULL; |
| 651 | |
| 652 | if (!chan) |
| 653 | return; |
| 654 | |
| 655 | for (i = 0; i < NR_CPUS; i++) { |
| 656 | if (!chan->buf[i] || chan->buf[i] == prev) |
| 657 | break; |
| 658 | relay_switch_subbuf(chan->buf[i], 0); |
| 659 | prev = chan->buf[i]; |
| 660 | } |
| 661 | } |
| 662 | EXPORT_SYMBOL_GPL(relay_flush); |
| 663 | |
| 664 | /** |
| 665 | * relay_file_open - open file op for relay files |
| 666 | * @inode: the inode |
| 667 | * @filp: the file |
| 668 | * |
| 669 | * Increments the channel buffer refcount. |
| 670 | */ |
| 671 | static int relay_file_open(struct inode *inode, struct file *filp) |
| 672 | { |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 673 | struct rchan_buf *buf = inode->i_private; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 674 | kref_get(&buf->kref); |
| 675 | filp->private_data = buf; |
| 676 | |
| 677 | return 0; |
| 678 | } |
| 679 | |
| 680 | /** |
| 681 | * relay_file_mmap - mmap file op for relay files |
| 682 | * @filp: the file |
| 683 | * @vma: the vma describing what to map |
| 684 | * |
| 685 | * Calls upon relay_mmap_buf to map the file into user space. |
| 686 | */ |
| 687 | static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma) |
| 688 | { |
| 689 | struct rchan_buf *buf = filp->private_data; |
| 690 | return relay_mmap_buf(buf, vma); |
| 691 | } |
| 692 | |
| 693 | /** |
| 694 | * relay_file_poll - poll file op for relay files |
| 695 | * @filp: the file |
| 696 | * @wait: poll table |
| 697 | * |
| 698 | * Poll implemention. |
| 699 | */ |
| 700 | static unsigned int relay_file_poll(struct file *filp, poll_table *wait) |
| 701 | { |
| 702 | unsigned int mask = 0; |
| 703 | struct rchan_buf *buf = filp->private_data; |
| 704 | |
| 705 | if (buf->finalized) |
| 706 | return POLLERR; |
| 707 | |
| 708 | if (filp->f_mode & FMODE_READ) { |
| 709 | poll_wait(filp, &buf->read_wait, wait); |
| 710 | if (!relay_buf_empty(buf)) |
| 711 | mask |= POLLIN | POLLRDNORM; |
| 712 | } |
| 713 | |
| 714 | return mask; |
| 715 | } |
| 716 | |
| 717 | /** |
| 718 | * relay_file_release - release file op for relay files |
| 719 | * @inode: the inode |
| 720 | * @filp: the file |
| 721 | * |
| 722 | * Decrements the channel refcount, as the filesystem is |
| 723 | * no longer using it. |
| 724 | */ |
| 725 | static int relay_file_release(struct inode *inode, struct file *filp) |
| 726 | { |
| 727 | struct rchan_buf *buf = filp->private_data; |
| 728 | kref_put(&buf->kref, relay_remove_buf); |
| 729 | |
| 730 | return 0; |
| 731 | } |
| 732 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 733 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 734 | * relay_file_read_consume - update the consumed count for the buffer |
| 735 | */ |
| 736 | static void relay_file_read_consume(struct rchan_buf *buf, |
| 737 | size_t read_pos, |
| 738 | size_t bytes_consumed) |
| 739 | { |
| 740 | size_t subbuf_size = buf->chan->subbuf_size; |
| 741 | size_t n_subbufs = buf->chan->n_subbufs; |
| 742 | size_t read_subbuf; |
| 743 | |
| 744 | if (buf->bytes_consumed + bytes_consumed > subbuf_size) { |
| 745 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); |
| 746 | buf->bytes_consumed = 0; |
| 747 | } |
| 748 | |
| 749 | buf->bytes_consumed += bytes_consumed; |
| 750 | read_subbuf = read_pos / buf->chan->subbuf_size; |
| 751 | if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) { |
| 752 | if ((read_subbuf == buf->subbufs_produced % n_subbufs) && |
| 753 | (buf->offset == subbuf_size)) |
| 754 | return; |
| 755 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); |
| 756 | buf->bytes_consumed = 0; |
| 757 | } |
| 758 | } |
| 759 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 760 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 761 | * relay_file_read_avail - boolean, are there unconsumed bytes available? |
| 762 | */ |
| 763 | static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos) |
| 764 | { |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 765 | size_t subbuf_size = buf->chan->subbuf_size; |
| 766 | size_t n_subbufs = buf->chan->n_subbufs; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 767 | size_t produced = buf->subbufs_produced; |
| 768 | size_t consumed = buf->subbufs_consumed; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 769 | |
| 770 | relay_file_read_consume(buf, read_pos, 0); |
| 771 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 772 | if (unlikely(buf->offset > subbuf_size)) { |
| 773 | if (produced == consumed) |
| 774 | return 0; |
| 775 | return 1; |
| 776 | } |
| 777 | |
| 778 | if (unlikely(produced - consumed >= n_subbufs)) { |
| 779 | consumed = (produced / n_subbufs) * n_subbufs; |
| 780 | buf->subbufs_consumed = consumed; |
| 781 | } |
| 782 | |
| 783 | produced = (produced % n_subbufs) * subbuf_size + buf->offset; |
| 784 | consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed; |
| 785 | |
| 786 | if (consumed > produced) |
| 787 | produced += n_subbufs * subbuf_size; |
| 788 | |
| 789 | if (consumed == produced) |
| 790 | return 0; |
| 791 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 792 | return 1; |
| 793 | } |
| 794 | |
| 795 | /** |
| 796 | * relay_file_read_subbuf_avail - return bytes available in sub-buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 797 | * @read_pos: file read position |
| 798 | * @buf: relay channel buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 799 | */ |
| 800 | static size_t relay_file_read_subbuf_avail(size_t read_pos, |
| 801 | struct rchan_buf *buf) |
| 802 | { |
| 803 | size_t padding, avail = 0; |
| 804 | size_t read_subbuf, read_offset, write_subbuf, write_offset; |
| 805 | size_t subbuf_size = buf->chan->subbuf_size; |
| 806 | |
| 807 | write_subbuf = (buf->data - buf->start) / subbuf_size; |
| 808 | write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset; |
| 809 | read_subbuf = read_pos / subbuf_size; |
| 810 | read_offset = read_pos % subbuf_size; |
| 811 | padding = buf->padding[read_subbuf]; |
| 812 | |
| 813 | if (read_subbuf == write_subbuf) { |
| 814 | if (read_offset + padding < write_offset) |
| 815 | avail = write_offset - (read_offset + padding); |
| 816 | } else |
| 817 | avail = (subbuf_size - padding) - read_offset; |
| 818 | |
| 819 | return avail; |
| 820 | } |
| 821 | |
| 822 | /** |
| 823 | * relay_file_read_start_pos - find the first available byte to read |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 824 | * @read_pos: file read position |
| 825 | * @buf: relay channel buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 826 | * |
| 827 | * If the read_pos is in the middle of padding, return the |
| 828 | * position of the first actually available byte, otherwise |
| 829 | * return the original value. |
| 830 | */ |
| 831 | static size_t relay_file_read_start_pos(size_t read_pos, |
| 832 | struct rchan_buf *buf) |
| 833 | { |
| 834 | size_t read_subbuf, padding, padding_start, padding_end; |
| 835 | size_t subbuf_size = buf->chan->subbuf_size; |
| 836 | size_t n_subbufs = buf->chan->n_subbufs; |
| 837 | |
| 838 | read_subbuf = read_pos / subbuf_size; |
| 839 | padding = buf->padding[read_subbuf]; |
| 840 | padding_start = (read_subbuf + 1) * subbuf_size - padding; |
| 841 | padding_end = (read_subbuf + 1) * subbuf_size; |
| 842 | if (read_pos >= padding_start && read_pos < padding_end) { |
| 843 | read_subbuf = (read_subbuf + 1) % n_subbufs; |
| 844 | read_pos = read_subbuf * subbuf_size; |
| 845 | } |
| 846 | |
| 847 | return read_pos; |
| 848 | } |
| 849 | |
| 850 | /** |
| 851 | * relay_file_read_end_pos - return the new read position |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 852 | * @read_pos: file read position |
| 853 | * @buf: relay channel buffer |
| 854 | * @count: number of bytes to be read |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 855 | */ |
| 856 | static size_t relay_file_read_end_pos(struct rchan_buf *buf, |
| 857 | size_t read_pos, |
| 858 | size_t count) |
| 859 | { |
| 860 | size_t read_subbuf, padding, end_pos; |
| 861 | size_t subbuf_size = buf->chan->subbuf_size; |
| 862 | size_t n_subbufs = buf->chan->n_subbufs; |
| 863 | |
| 864 | read_subbuf = read_pos / subbuf_size; |
| 865 | padding = buf->padding[read_subbuf]; |
| 866 | if (read_pos % subbuf_size + count + padding == subbuf_size) |
| 867 | end_pos = (read_subbuf + 1) * subbuf_size; |
| 868 | else |
| 869 | end_pos = read_pos + count; |
| 870 | if (end_pos >= subbuf_size * n_subbufs) |
| 871 | end_pos = 0; |
| 872 | |
| 873 | return end_pos; |
| 874 | } |
| 875 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 876 | /* |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 877 | * subbuf_read_actor - read up to one subbuf's worth of data |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 878 | */ |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 879 | static int subbuf_read_actor(size_t read_start, |
| 880 | struct rchan_buf *buf, |
| 881 | size_t avail, |
| 882 | read_descriptor_t *desc, |
| 883 | read_actor_t actor) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 884 | { |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 885 | void *from; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 886 | int ret = 0; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 887 | |
| 888 | from = buf->start + read_start; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 889 | ret = avail; |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 890 | if (copy_to_user(desc->arg.buf, from, avail)) { |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 891 | desc->error = -EFAULT; |
| 892 | ret = 0; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 893 | } |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 894 | desc->arg.data += ret; |
| 895 | desc->written += ret; |
| 896 | desc->count -= ret; |
| 897 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 898 | return ret; |
| 899 | } |
| 900 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 901 | /* |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 902 | * subbuf_send_actor - send up to one subbuf's worth of data |
| 903 | */ |
| 904 | static int subbuf_send_actor(size_t read_start, |
| 905 | struct rchan_buf *buf, |
| 906 | size_t avail, |
| 907 | read_descriptor_t *desc, |
| 908 | read_actor_t actor) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 909 | { |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 910 | unsigned long pidx, poff; |
| 911 | unsigned int subbuf_pages; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 912 | int ret = 0; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 913 | |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 914 | subbuf_pages = buf->chan->alloc_size >> PAGE_SHIFT; |
| 915 | pidx = (read_start / PAGE_SIZE) % subbuf_pages; |
| 916 | poff = read_start & ~PAGE_MASK; |
| 917 | while (avail) { |
| 918 | struct page *p = buf->page_array[pidx]; |
| 919 | unsigned int len; |
| 920 | |
| 921 | len = PAGE_SIZE - poff; |
| 922 | if (len > avail) |
| 923 | len = avail; |
| 924 | |
| 925 | len = actor(desc, p, poff, len); |
| 926 | if (desc->error) |
| 927 | break; |
| 928 | |
| 929 | avail -= len; |
| 930 | ret += len; |
| 931 | poff = 0; |
| 932 | pidx = (pidx + 1) % subbuf_pages; |
| 933 | } |
| 934 | |
| 935 | return ret; |
| 936 | } |
| 937 | |
| 938 | typedef int (*subbuf_actor_t) (size_t read_start, |
| 939 | struct rchan_buf *buf, |
| 940 | size_t avail, |
| 941 | read_descriptor_t *desc, |
| 942 | read_actor_t actor); |
| 943 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 944 | /* |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 945 | * relay_file_read_subbufs - read count bytes, bridging subbuf boundaries |
| 946 | */ |
| 947 | static inline ssize_t relay_file_read_subbufs(struct file *filp, |
| 948 | loff_t *ppos, |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 949 | subbuf_actor_t subbuf_actor, |
| 950 | read_actor_t actor, |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 951 | read_descriptor_t *desc) |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 952 | { |
| 953 | struct rchan_buf *buf = filp->private_data; |
| 954 | size_t read_start, avail; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 955 | int ret; |
| 956 | |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 957 | if (!desc->count) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 958 | return 0; |
| 959 | |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 960 | mutex_lock(&filp->f_dentry->d_inode->i_mutex); |
| 961 | do { |
| 962 | if (!relay_file_read_avail(buf, *ppos)) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 963 | break; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 964 | |
| 965 | read_start = relay_file_read_start_pos(*ppos, buf); |
| 966 | avail = relay_file_read_subbuf_avail(read_start, buf); |
| 967 | if (!avail) |
| 968 | break; |
| 969 | |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 970 | avail = min(desc->count, avail); |
| 971 | ret = subbuf_actor(read_start, buf, avail, desc, actor); |
| 972 | if (desc->error < 0) |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 973 | break; |
| 974 | |
| 975 | if (ret) { |
| 976 | relay_file_read_consume(buf, read_start, ret); |
| 977 | *ppos = relay_file_read_end_pos(buf, read_start, ret); |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 978 | } |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 979 | } while (desc->count && ret); |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 980 | mutex_unlock(&filp->f_dentry->d_inode->i_mutex); |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 981 | |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 982 | return desc->written; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 983 | } |
| 984 | |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 985 | static ssize_t relay_file_read(struct file *filp, |
| 986 | char __user *buffer, |
| 987 | size_t count, |
| 988 | loff_t *ppos) |
| 989 | { |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 990 | read_descriptor_t desc; |
| 991 | desc.written = 0; |
| 992 | desc.count = count; |
| 993 | desc.arg.buf = buffer; |
| 994 | desc.error = 0; |
| 995 | return relay_file_read_subbufs(filp, ppos, subbuf_read_actor, |
| 996 | NULL, &desc); |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 997 | } |
| 998 | |
| 999 | static ssize_t relay_file_sendfile(struct file *filp, |
| 1000 | loff_t *ppos, |
| 1001 | size_t count, |
| 1002 | read_actor_t actor, |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1003 | void *target) |
| 1004 | { |
Al Viro | ba2397e | 2006-10-10 22:46:57 +0100 | [diff] [blame] | 1005 | read_descriptor_t desc; |
| 1006 | desc.written = 0; |
| 1007 | desc.count = count; |
| 1008 | desc.arg.data = target; |
| 1009 | desc.error = 0; |
| 1010 | return relay_file_read_subbufs(filp, ppos, subbuf_send_actor, |
| 1011 | actor, &desc); |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1012 | } |
| 1013 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1014 | struct file_operations relay_file_operations = { |
| 1015 | .open = relay_file_open, |
| 1016 | .poll = relay_file_poll, |
| 1017 | .mmap = relay_file_mmap, |
| 1018 | .read = relay_file_read, |
| 1019 | .llseek = no_llseek, |
| 1020 | .release = relay_file_release, |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1021 | .sendfile = relay_file_sendfile, |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1022 | }; |
| 1023 | EXPORT_SYMBOL_GPL(relay_file_operations); |