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1 | /* | |
2 | * Public API and common code for kernel->userspace relay file support. | |
3 | * | |
4 | * See Documentation/filesystems/relay.txt for an overview. | |
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 | * November 2006 - CPU hotplug support by Mathieu Desnoyers | |
11 | * (mathieu.desnoyers@polymtl.ca) | |
12 | * | |
13 | * This file is released under the GPL. | |
14 | */ | |
15 | #include <linux/errno.h> | |
16 | #include <linux/stddef.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/relay.h> | |
21 | #include <linux/vmalloc.h> | |
22 | #include <linux/mm.h> | |
23 | #include <linux/cpu.h> | |
24 | #include <linux/splice.h> | |
25 | ||
26 | /* list of open channels, for cpu hotplug */ | |
27 | static DEFINE_MUTEX(relay_channels_mutex); | |
28 | static LIST_HEAD(relay_channels); | |
29 | ||
30 | /* | |
31 | * close() vm_op implementation for relay file mapping. | |
32 | */ | |
33 | static void relay_file_mmap_close(struct vm_area_struct *vma) | |
34 | { | |
35 | struct rchan_buf *buf = vma->vm_private_data; | |
36 | buf->chan->cb->buf_unmapped(buf, vma->vm_file); | |
37 | } | |
38 | ||
39 | /* | |
40 | * fault() vm_op implementation for relay file mapping. | |
41 | */ | |
42 | static int relay_buf_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
43 | { | |
44 | struct page *page; | |
45 | struct rchan_buf *buf = vma->vm_private_data; | |
46 | pgoff_t pgoff = vmf->pgoff; | |
47 | ||
48 | if (!buf) | |
49 | return VM_FAULT_OOM; | |
50 | ||
51 | page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT)); | |
52 | if (!page) | |
53 | return VM_FAULT_SIGBUS; | |
54 | get_page(page); | |
55 | vmf->page = page; | |
56 | ||
57 | return 0; | |
58 | } | |
59 | ||
60 | /* | |
61 | * vm_ops for relay file mappings. | |
62 | */ | |
63 | static struct vm_operations_struct relay_file_mmap_ops = { | |
64 | .fault = relay_buf_fault, | |
65 | .close = relay_file_mmap_close, | |
66 | }; | |
67 | ||
68 | /* | |
69 | * allocate an array of pointers of struct page | |
70 | */ | |
71 | static struct page **relay_alloc_page_array(unsigned int n_pages) | |
72 | { | |
73 | struct page **array; | |
74 | size_t pa_size = n_pages * sizeof(struct page *); | |
75 | ||
76 | if (pa_size > PAGE_SIZE) { | |
77 | array = vmalloc(pa_size); | |
78 | if (array) | |
79 | memset(array, 0, pa_size); | |
80 | } else { | |
81 | array = kzalloc(pa_size, GFP_KERNEL); | |
82 | } | |
83 | return array; | |
84 | } | |
85 | ||
86 | /* | |
87 | * free an array of pointers of struct page | |
88 | */ | |
89 | static void relay_free_page_array(struct page **array) | |
90 | { | |
91 | if (is_vmalloc_addr(array)) | |
92 | vfree(array); | |
93 | else | |
94 | kfree(array); | |
95 | } | |
96 | ||
97 | /** | |
98 | * relay_mmap_buf: - mmap channel buffer to process address space | |
99 | * @buf: relay channel buffer | |
100 | * @vma: vm_area_struct describing memory to be mapped | |
101 | * | |
102 | * Returns 0 if ok, negative on error | |
103 | * | |
104 | * Caller should already have grabbed mmap_sem. | |
105 | */ | |
106 | static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma) | |
107 | { | |
108 | unsigned long length = vma->vm_end - vma->vm_start; | |
109 | struct file *filp = vma->vm_file; | |
110 | ||
111 | if (!buf) | |
112 | return -EBADF; | |
113 | ||
114 | if (length != (unsigned long)buf->chan->alloc_size) | |
115 | return -EINVAL; | |
116 | ||
117 | vma->vm_ops = &relay_file_mmap_ops; | |
118 | vma->vm_flags |= VM_DONTEXPAND; | |
119 | vma->vm_private_data = buf; | |
120 | buf->chan->cb->buf_mapped(buf, filp); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | /** | |
126 | * relay_alloc_buf - allocate a channel buffer | |
127 | * @buf: the buffer struct | |
128 | * @size: total size of the buffer | |
129 | * | |
130 | * Returns a pointer to the resulting buffer, %NULL if unsuccessful. The | |
131 | * passed in size will get page aligned, if it isn't already. | |
132 | */ | |
133 | static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size) | |
134 | { | |
135 | void *mem; | |
136 | unsigned int i, j, n_pages; | |
137 | ||
138 | *size = PAGE_ALIGN(*size); | |
139 | n_pages = *size >> PAGE_SHIFT; | |
140 | ||
141 | buf->page_array = relay_alloc_page_array(n_pages); | |
142 | if (!buf->page_array) | |
143 | return NULL; | |
144 | ||
145 | for (i = 0; i < n_pages; i++) { | |
146 | buf->page_array[i] = alloc_page(GFP_KERNEL); | |
147 | if (unlikely(!buf->page_array[i])) | |
148 | goto depopulate; | |
149 | set_page_private(buf->page_array[i], (unsigned long)buf); | |
150 | } | |
151 | mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL); | |
152 | if (!mem) | |
153 | goto depopulate; | |
154 | ||
155 | memset(mem, 0, *size); | |
156 | buf->page_count = n_pages; | |
157 | return mem; | |
158 | ||
159 | depopulate: | |
160 | for (j = 0; j < i; j++) | |
161 | __free_page(buf->page_array[j]); | |
162 | relay_free_page_array(buf->page_array); | |
163 | return NULL; | |
164 | } | |
165 | ||
166 | /** | |
167 | * relay_create_buf - allocate and initialize a channel buffer | |
168 | * @chan: the relay channel | |
169 | * | |
170 | * Returns channel buffer if successful, %NULL otherwise. | |
171 | */ | |
172 | static struct rchan_buf *relay_create_buf(struct rchan *chan) | |
173 | { | |
174 | struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL); | |
175 | if (!buf) | |
176 | return NULL; | |
177 | ||
178 | buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL); | |
179 | if (!buf->padding) | |
180 | goto free_buf; | |
181 | ||
182 | buf->start = relay_alloc_buf(buf, &chan->alloc_size); | |
183 | if (!buf->start) | |
184 | goto free_buf; | |
185 | ||
186 | buf->chan = chan; | |
187 | kref_get(&buf->chan->kref); | |
188 | return buf; | |
189 | ||
190 | free_buf: | |
191 | kfree(buf->padding); | |
192 | kfree(buf); | |
193 | return NULL; | |
194 | } | |
195 | ||
196 | /** | |
197 | * relay_destroy_channel - free the channel struct | |
198 | * @kref: target kernel reference that contains the relay channel | |
199 | * | |
200 | * Should only be called from kref_put(). | |
201 | */ | |
202 | static void relay_destroy_channel(struct kref *kref) | |
203 | { | |
204 | struct rchan *chan = container_of(kref, struct rchan, kref); | |
205 | kfree(chan); | |
206 | } | |
207 | ||
208 | /** | |
209 | * relay_destroy_buf - destroy an rchan_buf struct and associated buffer | |
210 | * @buf: the buffer struct | |
211 | */ | |
212 | static void relay_destroy_buf(struct rchan_buf *buf) | |
213 | { | |
214 | struct rchan *chan = buf->chan; | |
215 | unsigned int i; | |
216 | ||
217 | if (likely(buf->start)) { | |
218 | vunmap(buf->start); | |
219 | for (i = 0; i < buf->page_count; i++) | |
220 | __free_page(buf->page_array[i]); | |
221 | relay_free_page_array(buf->page_array); | |
222 | } | |
223 | chan->buf[buf->cpu] = NULL; | |
224 | kfree(buf->padding); | |
225 | kfree(buf); | |
226 | kref_put(&chan->kref, relay_destroy_channel); | |
227 | } | |
228 | ||
229 | /** | |
230 | * relay_remove_buf - remove a channel buffer | |
231 | * @kref: target kernel reference that contains the relay buffer | |
232 | * | |
233 | * Removes the file from the fileystem, which also frees the | |
234 | * rchan_buf_struct and the channel buffer. Should only be called from | |
235 | * kref_put(). | |
236 | */ | |
237 | static void relay_remove_buf(struct kref *kref) | |
238 | { | |
239 | struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); | |
240 | buf->chan->cb->remove_buf_file(buf->dentry); | |
241 | relay_destroy_buf(buf); | |
242 | } | |
243 | ||
244 | /** | |
245 | * relay_buf_empty - boolean, is the channel buffer empty? | |
246 | * @buf: channel buffer | |
247 | * | |
248 | * Returns 1 if the buffer is empty, 0 otherwise. | |
249 | */ | |
250 | static int relay_buf_empty(struct rchan_buf *buf) | |
251 | { | |
252 | return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1; | |
253 | } | |
254 | ||
255 | /** | |
256 | * relay_buf_full - boolean, is the channel buffer full? | |
257 | * @buf: channel buffer | |
258 | * | |
259 | * Returns 1 if the buffer is full, 0 otherwise. | |
260 | */ | |
261 | int relay_buf_full(struct rchan_buf *buf) | |
262 | { | |
263 | size_t ready = buf->subbufs_produced - buf->subbufs_consumed; | |
264 | return (ready >= buf->chan->n_subbufs) ? 1 : 0; | |
265 | } | |
266 | EXPORT_SYMBOL_GPL(relay_buf_full); | |
267 | ||
268 | /* | |
269 | * High-level relay kernel API and associated functions. | |
270 | */ | |
271 | ||
272 | /* | |
273 | * rchan_callback implementations defining default channel behavior. Used | |
274 | * in place of corresponding NULL values in client callback struct. | |
275 | */ | |
276 | ||
277 | /* | |
278 | * subbuf_start() default callback. Does nothing. | |
279 | */ | |
280 | static int subbuf_start_default_callback (struct rchan_buf *buf, | |
281 | void *subbuf, | |
282 | void *prev_subbuf, | |
283 | size_t prev_padding) | |
284 | { | |
285 | if (relay_buf_full(buf)) | |
286 | return 0; | |
287 | ||
288 | return 1; | |
289 | } | |
290 | ||
291 | /* | |
292 | * buf_mapped() default callback. Does nothing. | |
293 | */ | |
294 | static void buf_mapped_default_callback(struct rchan_buf *buf, | |
295 | struct file *filp) | |
296 | { | |
297 | } | |
298 | ||
299 | /* | |
300 | * buf_unmapped() default callback. Does nothing. | |
301 | */ | |
302 | static void buf_unmapped_default_callback(struct rchan_buf *buf, | |
303 | struct file *filp) | |
304 | { | |
305 | } | |
306 | ||
307 | /* | |
308 | * create_buf_file_create() default callback. Does nothing. | |
309 | */ | |
310 | static struct dentry *create_buf_file_default_callback(const char *filename, | |
311 | struct dentry *parent, | |
312 | int mode, | |
313 | struct rchan_buf *buf, | |
314 | int *is_global) | |
315 | { | |
316 | return NULL; | |
317 | } | |
318 | ||
319 | /* | |
320 | * remove_buf_file() default callback. Does nothing. | |
321 | */ | |
322 | static int remove_buf_file_default_callback(struct dentry *dentry) | |
323 | { | |
324 | return -EINVAL; | |
325 | } | |
326 | ||
327 | /* relay channel default callbacks */ | |
328 | static struct rchan_callbacks default_channel_callbacks = { | |
329 | .subbuf_start = subbuf_start_default_callback, | |
330 | .buf_mapped = buf_mapped_default_callback, | |
331 | .buf_unmapped = buf_unmapped_default_callback, | |
332 | .create_buf_file = create_buf_file_default_callback, | |
333 | .remove_buf_file = remove_buf_file_default_callback, | |
334 | }; | |
335 | ||
336 | /** | |
337 | * wakeup_readers - wake up readers waiting on a channel | |
338 | * @data: contains the channel buffer | |
339 | * | |
340 | * This is the timer function used to defer reader waking. | |
341 | */ | |
342 | static void wakeup_readers(unsigned long data) | |
343 | { | |
344 | struct rchan_buf *buf = (struct rchan_buf *)data; | |
345 | wake_up_interruptible(&buf->read_wait); | |
346 | } | |
347 | ||
348 | /** | |
349 | * __relay_reset - reset a channel buffer | |
350 | * @buf: the channel buffer | |
351 | * @init: 1 if this is a first-time initialization | |
352 | * | |
353 | * See relay_reset() for description of effect. | |
354 | */ | |
355 | static void __relay_reset(struct rchan_buf *buf, unsigned int init) | |
356 | { | |
357 | size_t i; | |
358 | ||
359 | if (init) { | |
360 | init_waitqueue_head(&buf->read_wait); | |
361 | kref_init(&buf->kref); | |
362 | setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf); | |
363 | } else | |
364 | del_timer_sync(&buf->timer); | |
365 | ||
366 | buf->subbufs_produced = 0; | |
367 | buf->subbufs_consumed = 0; | |
368 | buf->bytes_consumed = 0; | |
369 | buf->finalized = 0; | |
370 | buf->data = buf->start; | |
371 | buf->offset = 0; | |
372 | ||
373 | for (i = 0; i < buf->chan->n_subbufs; i++) | |
374 | buf->padding[i] = 0; | |
375 | ||
376 | buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0); | |
377 | } | |
378 | ||
379 | /** | |
380 | * relay_reset - reset the channel | |
381 | * @chan: the channel | |
382 | * | |
383 | * This has the effect of erasing all data from all channel buffers | |
384 | * and restarting the channel in its initial state. The buffers | |
385 | * are not freed, so any mappings are still in effect. | |
386 | * | |
387 | * NOTE. Care should be taken that the channel isn't actually | |
388 | * being used by anything when this call is made. | |
389 | */ | |
390 | void relay_reset(struct rchan *chan) | |
391 | { | |
392 | unsigned int i; | |
393 | ||
394 | if (!chan) | |
395 | return; | |
396 | ||
397 | if (chan->is_global && chan->buf[0]) { | |
398 | __relay_reset(chan->buf[0], 0); | |
399 | return; | |
400 | } | |
401 | ||
402 | mutex_lock(&relay_channels_mutex); | |
403 | for_each_online_cpu(i) | |
404 | if (chan->buf[i]) | |
405 | __relay_reset(chan->buf[i], 0); | |
406 | mutex_unlock(&relay_channels_mutex); | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(relay_reset); | |
409 | ||
410 | /* | |
411 | * relay_open_buf - create a new relay channel buffer | |
412 | * | |
413 | * used by relay_open() and CPU hotplug. | |
414 | */ | |
415 | static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) | |
416 | { | |
417 | struct rchan_buf *buf = NULL; | |
418 | struct dentry *dentry; | |
419 | char *tmpname; | |
420 | ||
421 | if (chan->is_global) | |
422 | return chan->buf[0]; | |
423 | ||
424 | tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL); | |
425 | if (!tmpname) | |
426 | goto end; | |
427 | snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu); | |
428 | ||
429 | buf = relay_create_buf(chan); | |
430 | if (!buf) | |
431 | goto free_name; | |
432 | ||
433 | buf->cpu = cpu; | |
434 | __relay_reset(buf, 1); | |
435 | ||
436 | /* Create file in fs */ | |
437 | dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, | |
438 | buf, &chan->is_global); | |
439 | if (!dentry) | |
440 | goto free_buf; | |
441 | ||
442 | buf->dentry = dentry; | |
443 | ||
444 | if(chan->is_global) { | |
445 | chan->buf[0] = buf; | |
446 | buf->cpu = 0; | |
447 | } | |
448 | ||
449 | goto free_name; | |
450 | ||
451 | free_buf: | |
452 | relay_destroy_buf(buf); | |
453 | buf = NULL; | |
454 | free_name: | |
455 | kfree(tmpname); | |
456 | end: | |
457 | return buf; | |
458 | } | |
459 | ||
460 | /** | |
461 | * relay_close_buf - close a channel buffer | |
462 | * @buf: channel buffer | |
463 | * | |
464 | * Marks the buffer finalized and restores the default callbacks. | |
465 | * The channel buffer and channel buffer data structure are then freed | |
466 | * automatically when the last reference is given up. | |
467 | */ | |
468 | static void relay_close_buf(struct rchan_buf *buf) | |
469 | { | |
470 | buf->finalized = 1; | |
471 | del_timer_sync(&buf->timer); | |
472 | kref_put(&buf->kref, relay_remove_buf); | |
473 | } | |
474 | ||
475 | static void setup_callbacks(struct rchan *chan, | |
476 | struct rchan_callbacks *cb) | |
477 | { | |
478 | if (!cb) { | |
479 | chan->cb = &default_channel_callbacks; | |
480 | return; | |
481 | } | |
482 | ||
483 | if (!cb->subbuf_start) | |
484 | cb->subbuf_start = subbuf_start_default_callback; | |
485 | if (!cb->buf_mapped) | |
486 | cb->buf_mapped = buf_mapped_default_callback; | |
487 | if (!cb->buf_unmapped) | |
488 | cb->buf_unmapped = buf_unmapped_default_callback; | |
489 | if (!cb->create_buf_file) | |
490 | cb->create_buf_file = create_buf_file_default_callback; | |
491 | if (!cb->remove_buf_file) | |
492 | cb->remove_buf_file = remove_buf_file_default_callback; | |
493 | chan->cb = cb; | |
494 | } | |
495 | ||
496 | /** | |
497 | * relay_hotcpu_callback - CPU hotplug callback | |
498 | * @nb: notifier block | |
499 | * @action: hotplug action to take | |
500 | * @hcpu: CPU number | |
501 | * | |
502 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
503 | */ | |
504 | static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb, | |
505 | unsigned long action, | |
506 | void *hcpu) | |
507 | { | |
508 | unsigned int hotcpu = (unsigned long)hcpu; | |
509 | struct rchan *chan; | |
510 | ||
511 | switch(action) { | |
512 | case CPU_UP_PREPARE: | |
513 | case CPU_UP_PREPARE_FROZEN: | |
514 | mutex_lock(&relay_channels_mutex); | |
515 | list_for_each_entry(chan, &relay_channels, list) { | |
516 | if (chan->buf[hotcpu]) | |
517 | continue; | |
518 | chan->buf[hotcpu] = relay_open_buf(chan, hotcpu); | |
519 | if(!chan->buf[hotcpu]) { | |
520 | printk(KERN_ERR | |
521 | "relay_hotcpu_callback: cpu %d buffer " | |
522 | "creation failed\n", hotcpu); | |
523 | mutex_unlock(&relay_channels_mutex); | |
524 | return NOTIFY_BAD; | |
525 | } | |
526 | } | |
527 | mutex_unlock(&relay_channels_mutex); | |
528 | break; | |
529 | case CPU_DEAD: | |
530 | case CPU_DEAD_FROZEN: | |
531 | /* No need to flush the cpu : will be flushed upon | |
532 | * final relay_flush() call. */ | |
533 | break; | |
534 | } | |
535 | return NOTIFY_OK; | |
536 | } | |
537 | ||
538 | /** | |
539 | * relay_open - create a new relay channel | |
540 | * @base_filename: base name of files to create | |
541 | * @parent: dentry of parent directory, %NULL for root directory | |
542 | * @subbuf_size: size of sub-buffers | |
543 | * @n_subbufs: number of sub-buffers | |
544 | * @cb: client callback functions | |
545 | * @private_data: user-defined data | |
546 | * | |
547 | * Returns channel pointer if successful, %NULL otherwise. | |
548 | * | |
549 | * Creates a channel buffer for each cpu using the sizes and | |
550 | * attributes specified. The created channel buffer files | |
551 | * will be named base_filename0...base_filenameN-1. File | |
552 | * permissions will be %S_IRUSR. | |
553 | */ | |
554 | struct rchan *relay_open(const char *base_filename, | |
555 | struct dentry *parent, | |
556 | size_t subbuf_size, | |
557 | size_t n_subbufs, | |
558 | struct rchan_callbacks *cb, | |
559 | void *private_data) | |
560 | { | |
561 | unsigned int i; | |
562 | struct rchan *chan; | |
563 | if (!base_filename) | |
564 | return NULL; | |
565 | ||
566 | if (!(subbuf_size && n_subbufs)) | |
567 | return NULL; | |
568 | ||
569 | chan = kzalloc(sizeof(struct rchan), GFP_KERNEL); | |
570 | if (!chan) | |
571 | return NULL; | |
572 | ||
573 | chan->version = RELAYFS_CHANNEL_VERSION; | |
574 | chan->n_subbufs = n_subbufs; | |
575 | chan->subbuf_size = subbuf_size; | |
576 | chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); | |
577 | chan->parent = parent; | |
578 | chan->private_data = private_data; | |
579 | strlcpy(chan->base_filename, base_filename, NAME_MAX); | |
580 | setup_callbacks(chan, cb); | |
581 | kref_init(&chan->kref); | |
582 | ||
583 | mutex_lock(&relay_channels_mutex); | |
584 | for_each_online_cpu(i) { | |
585 | chan->buf[i] = relay_open_buf(chan, i); | |
586 | if (!chan->buf[i]) | |
587 | goto free_bufs; | |
588 | } | |
589 | list_add(&chan->list, &relay_channels); | |
590 | mutex_unlock(&relay_channels_mutex); | |
591 | ||
592 | return chan; | |
593 | ||
594 | free_bufs: | |
595 | for_each_online_cpu(i) { | |
596 | if (!chan->buf[i]) | |
597 | break; | |
598 | relay_close_buf(chan->buf[i]); | |
599 | } | |
600 | ||
601 | kref_put(&chan->kref, relay_destroy_channel); | |
602 | mutex_unlock(&relay_channels_mutex); | |
603 | return NULL; | |
604 | } | |
605 | EXPORT_SYMBOL_GPL(relay_open); | |
606 | ||
607 | /** | |
608 | * relay_switch_subbuf - switch to a new sub-buffer | |
609 | * @buf: channel buffer | |
610 | * @length: size of current event | |
611 | * | |
612 | * Returns either the length passed in or 0 if full. | |
613 | * | |
614 | * Performs sub-buffer-switch tasks such as invoking callbacks, | |
615 | * updating padding counts, waking up readers, etc. | |
616 | */ | |
617 | size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) | |
618 | { | |
619 | void *old, *new; | |
620 | size_t old_subbuf, new_subbuf; | |
621 | ||
622 | if (unlikely(length > buf->chan->subbuf_size)) | |
623 | goto toobig; | |
624 | ||
625 | if (buf->offset != buf->chan->subbuf_size + 1) { | |
626 | buf->prev_padding = buf->chan->subbuf_size - buf->offset; | |
627 | old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; | |
628 | buf->padding[old_subbuf] = buf->prev_padding; | |
629 | buf->subbufs_produced++; | |
630 | buf->dentry->d_inode->i_size += buf->chan->subbuf_size - | |
631 | buf->padding[old_subbuf]; | |
632 | smp_mb(); | |
633 | if (waitqueue_active(&buf->read_wait)) | |
634 | /* | |
635 | * Calling wake_up_interruptible() from here | |
636 | * will deadlock if we happen to be logging | |
637 | * from the scheduler (trying to re-grab | |
638 | * rq->lock), so defer it. | |
639 | */ | |
640 | __mod_timer(&buf->timer, jiffies + 1); | |
641 | } | |
642 | ||
643 | old = buf->data; | |
644 | new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; | |
645 | new = buf->start + new_subbuf * buf->chan->subbuf_size; | |
646 | buf->offset = 0; | |
647 | if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) { | |
648 | buf->offset = buf->chan->subbuf_size + 1; | |
649 | return 0; | |
650 | } | |
651 | buf->data = new; | |
652 | buf->padding[new_subbuf] = 0; | |
653 | ||
654 | if (unlikely(length + buf->offset > buf->chan->subbuf_size)) | |
655 | goto toobig; | |
656 | ||
657 | return length; | |
658 | ||
659 | toobig: | |
660 | buf->chan->last_toobig = length; | |
661 | return 0; | |
662 | } | |
663 | EXPORT_SYMBOL_GPL(relay_switch_subbuf); | |
664 | ||
665 | /** | |
666 | * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count | |
667 | * @chan: the channel | |
668 | * @cpu: the cpu associated with the channel buffer to update | |
669 | * @subbufs_consumed: number of sub-buffers to add to current buf's count | |
670 | * | |
671 | * Adds to the channel buffer's consumed sub-buffer count. | |
672 | * subbufs_consumed should be the number of sub-buffers newly consumed, | |
673 | * not the total consumed. | |
674 | * | |
675 | * NOTE. Kernel clients don't need to call this function if the channel | |
676 | * mode is 'overwrite'. | |
677 | */ | |
678 | void relay_subbufs_consumed(struct rchan *chan, | |
679 | unsigned int cpu, | |
680 | size_t subbufs_consumed) | |
681 | { | |
682 | struct rchan_buf *buf; | |
683 | ||
684 | if (!chan) | |
685 | return; | |
686 | ||
687 | if (cpu >= NR_CPUS || !chan->buf[cpu]) | |
688 | return; | |
689 | ||
690 | buf = chan->buf[cpu]; | |
691 | buf->subbufs_consumed += subbufs_consumed; | |
692 | if (buf->subbufs_consumed > buf->subbufs_produced) | |
693 | buf->subbufs_consumed = buf->subbufs_produced; | |
694 | } | |
695 | EXPORT_SYMBOL_GPL(relay_subbufs_consumed); | |
696 | ||
697 | /** | |
698 | * relay_close - close the channel | |
699 | * @chan: the channel | |
700 | * | |
701 | * Closes all channel buffers and frees the channel. | |
702 | */ | |
703 | void relay_close(struct rchan *chan) | |
704 | { | |
705 | unsigned int i; | |
706 | ||
707 | if (!chan) | |
708 | return; | |
709 | ||
710 | mutex_lock(&relay_channels_mutex); | |
711 | if (chan->is_global && chan->buf[0]) | |
712 | relay_close_buf(chan->buf[0]); | |
713 | else | |
714 | for_each_possible_cpu(i) | |
715 | if (chan->buf[i]) | |
716 | relay_close_buf(chan->buf[i]); | |
717 | ||
718 | if (chan->last_toobig) | |
719 | printk(KERN_WARNING "relay: one or more items not logged " | |
720 | "[item size (%Zd) > sub-buffer size (%Zd)]\n", | |
721 | chan->last_toobig, chan->subbuf_size); | |
722 | ||
723 | list_del(&chan->list); | |
724 | kref_put(&chan->kref, relay_destroy_channel); | |
725 | mutex_unlock(&relay_channels_mutex); | |
726 | } | |
727 | EXPORT_SYMBOL_GPL(relay_close); | |
728 | ||
729 | /** | |
730 | * relay_flush - close the channel | |
731 | * @chan: the channel | |
732 | * | |
733 | * Flushes all channel buffers, i.e. forces buffer switch. | |
734 | */ | |
735 | void relay_flush(struct rchan *chan) | |
736 | { | |
737 | unsigned int i; | |
738 | ||
739 | if (!chan) | |
740 | return; | |
741 | ||
742 | if (chan->is_global && chan->buf[0]) { | |
743 | relay_switch_subbuf(chan->buf[0], 0); | |
744 | return; | |
745 | } | |
746 | ||
747 | mutex_lock(&relay_channels_mutex); | |
748 | for_each_possible_cpu(i) | |
749 | if (chan->buf[i]) | |
750 | relay_switch_subbuf(chan->buf[i], 0); | |
751 | mutex_unlock(&relay_channels_mutex); | |
752 | } | |
753 | EXPORT_SYMBOL_GPL(relay_flush); | |
754 | ||
755 | /** | |
756 | * relay_file_open - open file op for relay files | |
757 | * @inode: the inode | |
758 | * @filp: the file | |
759 | * | |
760 | * Increments the channel buffer refcount. | |
761 | */ | |
762 | static int relay_file_open(struct inode *inode, struct file *filp) | |
763 | { | |
764 | struct rchan_buf *buf = inode->i_private; | |
765 | kref_get(&buf->kref); | |
766 | filp->private_data = buf; | |
767 | ||
768 | return nonseekable_open(inode, filp); | |
769 | } | |
770 | ||
771 | /** | |
772 | * relay_file_mmap - mmap file op for relay files | |
773 | * @filp: the file | |
774 | * @vma: the vma describing what to map | |
775 | * | |
776 | * Calls upon relay_mmap_buf() to map the file into user space. | |
777 | */ | |
778 | static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma) | |
779 | { | |
780 | struct rchan_buf *buf = filp->private_data; | |
781 | return relay_mmap_buf(buf, vma); | |
782 | } | |
783 | ||
784 | /** | |
785 | * relay_file_poll - poll file op for relay files | |
786 | * @filp: the file | |
787 | * @wait: poll table | |
788 | * | |
789 | * Poll implemention. | |
790 | */ | |
791 | static unsigned int relay_file_poll(struct file *filp, poll_table *wait) | |
792 | { | |
793 | unsigned int mask = 0; | |
794 | struct rchan_buf *buf = filp->private_data; | |
795 | ||
796 | if (buf->finalized) | |
797 | return POLLERR; | |
798 | ||
799 | if (filp->f_mode & FMODE_READ) { | |
800 | poll_wait(filp, &buf->read_wait, wait); | |
801 | if (!relay_buf_empty(buf)) | |
802 | mask |= POLLIN | POLLRDNORM; | |
803 | } | |
804 | ||
805 | return mask; | |
806 | } | |
807 | ||
808 | /** | |
809 | * relay_file_release - release file op for relay files | |
810 | * @inode: the inode | |
811 | * @filp: the file | |
812 | * | |
813 | * Decrements the channel refcount, as the filesystem is | |
814 | * no longer using it. | |
815 | */ | |
816 | static int relay_file_release(struct inode *inode, struct file *filp) | |
817 | { | |
818 | struct rchan_buf *buf = filp->private_data; | |
819 | kref_put(&buf->kref, relay_remove_buf); | |
820 | ||
821 | return 0; | |
822 | } | |
823 | ||
824 | /* | |
825 | * relay_file_read_consume - update the consumed count for the buffer | |
826 | */ | |
827 | static void relay_file_read_consume(struct rchan_buf *buf, | |
828 | size_t read_pos, | |
829 | size_t bytes_consumed) | |
830 | { | |
831 | size_t subbuf_size = buf->chan->subbuf_size; | |
832 | size_t n_subbufs = buf->chan->n_subbufs; | |
833 | size_t read_subbuf; | |
834 | ||
835 | if (buf->bytes_consumed + bytes_consumed > subbuf_size) { | |
836 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); | |
837 | buf->bytes_consumed = 0; | |
838 | } | |
839 | ||
840 | buf->bytes_consumed += bytes_consumed; | |
841 | if (!read_pos) | |
842 | read_subbuf = buf->subbufs_consumed % n_subbufs; | |
843 | else | |
844 | read_subbuf = read_pos / buf->chan->subbuf_size; | |
845 | if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) { | |
846 | if ((read_subbuf == buf->subbufs_produced % n_subbufs) && | |
847 | (buf->offset == subbuf_size)) | |
848 | return; | |
849 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); | |
850 | buf->bytes_consumed = 0; | |
851 | } | |
852 | } | |
853 | ||
854 | /* | |
855 | * relay_file_read_avail - boolean, are there unconsumed bytes available? | |
856 | */ | |
857 | static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos) | |
858 | { | |
859 | size_t subbuf_size = buf->chan->subbuf_size; | |
860 | size_t n_subbufs = buf->chan->n_subbufs; | |
861 | size_t produced = buf->subbufs_produced; | |
862 | size_t consumed = buf->subbufs_consumed; | |
863 | ||
864 | relay_file_read_consume(buf, read_pos, 0); | |
865 | ||
866 | if (unlikely(buf->offset > subbuf_size)) { | |
867 | if (produced == consumed) | |
868 | return 0; | |
869 | return 1; | |
870 | } | |
871 | ||
872 | if (unlikely(produced - consumed >= n_subbufs)) { | |
873 | consumed = produced - n_subbufs + 1; | |
874 | buf->subbufs_consumed = consumed; | |
875 | buf->bytes_consumed = 0; | |
876 | } | |
877 | ||
878 | produced = (produced % n_subbufs) * subbuf_size + buf->offset; | |
879 | consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed; | |
880 | ||
881 | if (consumed > produced) | |
882 | produced += n_subbufs * subbuf_size; | |
883 | ||
884 | if (consumed == produced) | |
885 | return 0; | |
886 | ||
887 | return 1; | |
888 | } | |
889 | ||
890 | /** | |
891 | * relay_file_read_subbuf_avail - return bytes available in sub-buffer | |
892 | * @read_pos: file read position | |
893 | * @buf: relay channel buffer | |
894 | */ | |
895 | static size_t relay_file_read_subbuf_avail(size_t read_pos, | |
896 | struct rchan_buf *buf) | |
897 | { | |
898 | size_t padding, avail = 0; | |
899 | size_t read_subbuf, read_offset, write_subbuf, write_offset; | |
900 | size_t subbuf_size = buf->chan->subbuf_size; | |
901 | ||
902 | write_subbuf = (buf->data - buf->start) / subbuf_size; | |
903 | write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset; | |
904 | read_subbuf = read_pos / subbuf_size; | |
905 | read_offset = read_pos % subbuf_size; | |
906 | padding = buf->padding[read_subbuf]; | |
907 | ||
908 | if (read_subbuf == write_subbuf) { | |
909 | if (read_offset + padding < write_offset) | |
910 | avail = write_offset - (read_offset + padding); | |
911 | } else | |
912 | avail = (subbuf_size - padding) - read_offset; | |
913 | ||
914 | return avail; | |
915 | } | |
916 | ||
917 | /** | |
918 | * relay_file_read_start_pos - find the first available byte to read | |
919 | * @read_pos: file read position | |
920 | * @buf: relay channel buffer | |
921 | * | |
922 | * If the @read_pos is in the middle of padding, return the | |
923 | * position of the first actually available byte, otherwise | |
924 | * return the original value. | |
925 | */ | |
926 | static size_t relay_file_read_start_pos(size_t read_pos, | |
927 | struct rchan_buf *buf) | |
928 | { | |
929 | size_t read_subbuf, padding, padding_start, padding_end; | |
930 | size_t subbuf_size = buf->chan->subbuf_size; | |
931 | size_t n_subbufs = buf->chan->n_subbufs; | |
932 | size_t consumed = buf->subbufs_consumed % n_subbufs; | |
933 | ||
934 | if (!read_pos) | |
935 | read_pos = consumed * subbuf_size + buf->bytes_consumed; | |
936 | read_subbuf = read_pos / subbuf_size; | |
937 | padding = buf->padding[read_subbuf]; | |
938 | padding_start = (read_subbuf + 1) * subbuf_size - padding; | |
939 | padding_end = (read_subbuf + 1) * subbuf_size; | |
940 | if (read_pos >= padding_start && read_pos < padding_end) { | |
941 | read_subbuf = (read_subbuf + 1) % n_subbufs; | |
942 | read_pos = read_subbuf * subbuf_size; | |
943 | } | |
944 | ||
945 | return read_pos; | |
946 | } | |
947 | ||
948 | /** | |
949 | * relay_file_read_end_pos - return the new read position | |
950 | * @read_pos: file read position | |
951 | * @buf: relay channel buffer | |
952 | * @count: number of bytes to be read | |
953 | */ | |
954 | static size_t relay_file_read_end_pos(struct rchan_buf *buf, | |
955 | size_t read_pos, | |
956 | size_t count) | |
957 | { | |
958 | size_t read_subbuf, padding, end_pos; | |
959 | size_t subbuf_size = buf->chan->subbuf_size; | |
960 | size_t n_subbufs = buf->chan->n_subbufs; | |
961 | ||
962 | read_subbuf = read_pos / subbuf_size; | |
963 | padding = buf->padding[read_subbuf]; | |
964 | if (read_pos % subbuf_size + count + padding == subbuf_size) | |
965 | end_pos = (read_subbuf + 1) * subbuf_size; | |
966 | else | |
967 | end_pos = read_pos + count; | |
968 | if (end_pos >= subbuf_size * n_subbufs) | |
969 | end_pos = 0; | |
970 | ||
971 | return end_pos; | |
972 | } | |
973 | ||
974 | /* | |
975 | * subbuf_read_actor - read up to one subbuf's worth of data | |
976 | */ | |
977 | static int subbuf_read_actor(size_t read_start, | |
978 | struct rchan_buf *buf, | |
979 | size_t avail, | |
980 | read_descriptor_t *desc, | |
981 | read_actor_t actor) | |
982 | { | |
983 | void *from; | |
984 | int ret = 0; | |
985 | ||
986 | from = buf->start + read_start; | |
987 | ret = avail; | |
988 | if (copy_to_user(desc->arg.buf, from, avail)) { | |
989 | desc->error = -EFAULT; | |
990 | ret = 0; | |
991 | } | |
992 | desc->arg.data += ret; | |
993 | desc->written += ret; | |
994 | desc->count -= ret; | |
995 | ||
996 | return ret; | |
997 | } | |
998 | ||
999 | typedef int (*subbuf_actor_t) (size_t read_start, | |
1000 | struct rchan_buf *buf, | |
1001 | size_t avail, | |
1002 | read_descriptor_t *desc, | |
1003 | read_actor_t actor); | |
1004 | ||
1005 | /* | |
1006 | * relay_file_read_subbufs - read count bytes, bridging subbuf boundaries | |
1007 | */ | |
1008 | static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos, | |
1009 | subbuf_actor_t subbuf_actor, | |
1010 | read_actor_t actor, | |
1011 | read_descriptor_t *desc) | |
1012 | { | |
1013 | struct rchan_buf *buf = filp->private_data; | |
1014 | size_t read_start, avail; | |
1015 | int ret; | |
1016 | ||
1017 | if (!desc->count) | |
1018 | return 0; | |
1019 | ||
1020 | mutex_lock(&filp->f_path.dentry->d_inode->i_mutex); | |
1021 | do { | |
1022 | if (!relay_file_read_avail(buf, *ppos)) | |
1023 | break; | |
1024 | ||
1025 | read_start = relay_file_read_start_pos(*ppos, buf); | |
1026 | avail = relay_file_read_subbuf_avail(read_start, buf); | |
1027 | if (!avail) | |
1028 | break; | |
1029 | ||
1030 | avail = min(desc->count, avail); | |
1031 | ret = subbuf_actor(read_start, buf, avail, desc, actor); | |
1032 | if (desc->error < 0) | |
1033 | break; | |
1034 | ||
1035 | if (ret) { | |
1036 | relay_file_read_consume(buf, read_start, ret); | |
1037 | *ppos = relay_file_read_end_pos(buf, read_start, ret); | |
1038 | } | |
1039 | } while (desc->count && ret); | |
1040 | mutex_unlock(&filp->f_path.dentry->d_inode->i_mutex); | |
1041 | ||
1042 | return desc->written; | |
1043 | } | |
1044 | ||
1045 | static ssize_t relay_file_read(struct file *filp, | |
1046 | char __user *buffer, | |
1047 | size_t count, | |
1048 | loff_t *ppos) | |
1049 | { | |
1050 | read_descriptor_t desc; | |
1051 | desc.written = 0; | |
1052 | desc.count = count; | |
1053 | desc.arg.buf = buffer; | |
1054 | desc.error = 0; | |
1055 | return relay_file_read_subbufs(filp, ppos, subbuf_read_actor, | |
1056 | NULL, &desc); | |
1057 | } | |
1058 | ||
1059 | static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed) | |
1060 | { | |
1061 | rbuf->bytes_consumed += bytes_consumed; | |
1062 | ||
1063 | if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) { | |
1064 | relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1); | |
1065 | rbuf->bytes_consumed %= rbuf->chan->subbuf_size; | |
1066 | } | |
1067 | } | |
1068 | ||
1069 | static void relay_pipe_buf_release(struct pipe_inode_info *pipe, | |
1070 | struct pipe_buffer *buf) | |
1071 | { | |
1072 | struct rchan_buf *rbuf; | |
1073 | ||
1074 | rbuf = (struct rchan_buf *)page_private(buf->page); | |
1075 | relay_consume_bytes(rbuf, buf->private); | |
1076 | } | |
1077 | ||
1078 | static struct pipe_buf_operations relay_pipe_buf_ops = { | |
1079 | .can_merge = 0, | |
1080 | .map = generic_pipe_buf_map, | |
1081 | .unmap = generic_pipe_buf_unmap, | |
1082 | .confirm = generic_pipe_buf_confirm, | |
1083 | .release = relay_pipe_buf_release, | |
1084 | .steal = generic_pipe_buf_steal, | |
1085 | .get = generic_pipe_buf_get, | |
1086 | }; | |
1087 | ||
1088 | static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i) | |
1089 | { | |
1090 | } | |
1091 | ||
1092 | /* | |
1093 | * subbuf_splice_actor - splice up to one subbuf's worth of data | |
1094 | */ | |
1095 | static int subbuf_splice_actor(struct file *in, | |
1096 | loff_t *ppos, | |
1097 | struct pipe_inode_info *pipe, | |
1098 | size_t len, | |
1099 | unsigned int flags, | |
1100 | int *nonpad_ret) | |
1101 | { | |
1102 | unsigned int pidx, poff, total_len, subbuf_pages, nr_pages, ret; | |
1103 | struct rchan_buf *rbuf = in->private_data; | |
1104 | unsigned int subbuf_size = rbuf->chan->subbuf_size; | |
1105 | uint64_t pos = (uint64_t) *ppos; | |
1106 | uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size; | |
1107 | size_t read_start = (size_t) do_div(pos, alloc_size); | |
1108 | size_t read_subbuf = read_start / subbuf_size; | |
1109 | size_t padding = rbuf->padding[read_subbuf]; | |
1110 | size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding; | |
1111 | struct page *pages[PIPE_BUFFERS]; | |
1112 | struct partial_page partial[PIPE_BUFFERS]; | |
1113 | struct splice_pipe_desc spd = { | |
1114 | .pages = pages, | |
1115 | .nr_pages = 0, | |
1116 | .partial = partial, | |
1117 | .flags = flags, | |
1118 | .ops = &relay_pipe_buf_ops, | |
1119 | .spd_release = relay_page_release, | |
1120 | }; | |
1121 | ||
1122 | if (rbuf->subbufs_produced == rbuf->subbufs_consumed) | |
1123 | return 0; | |
1124 | ||
1125 | /* | |
1126 | * Adjust read len, if longer than what is available | |
1127 | */ | |
1128 | if (len > (subbuf_size - read_start % subbuf_size)) | |
1129 | len = subbuf_size - read_start % subbuf_size; | |
1130 | ||
1131 | subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT; | |
1132 | pidx = (read_start / PAGE_SIZE) % subbuf_pages; | |
1133 | poff = read_start & ~PAGE_MASK; | |
1134 | nr_pages = min_t(unsigned int, subbuf_pages, PIPE_BUFFERS); | |
1135 | ||
1136 | for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) { | |
1137 | unsigned int this_len, this_end, private; | |
1138 | unsigned int cur_pos = read_start + total_len; | |
1139 | ||
1140 | if (!len) | |
1141 | break; | |
1142 | ||
1143 | this_len = min_t(unsigned long, len, PAGE_SIZE - poff); | |
1144 | private = this_len; | |
1145 | ||
1146 | spd.pages[spd.nr_pages] = rbuf->page_array[pidx]; | |
1147 | spd.partial[spd.nr_pages].offset = poff; | |
1148 | ||
1149 | this_end = cur_pos + this_len; | |
1150 | if (this_end >= nonpad_end) { | |
1151 | this_len = nonpad_end - cur_pos; | |
1152 | private = this_len + padding; | |
1153 | } | |
1154 | spd.partial[spd.nr_pages].len = this_len; | |
1155 | spd.partial[spd.nr_pages].private = private; | |
1156 | ||
1157 | len -= this_len; | |
1158 | total_len += this_len; | |
1159 | poff = 0; | |
1160 | pidx = (pidx + 1) % subbuf_pages; | |
1161 | ||
1162 | if (this_end >= nonpad_end) { | |
1163 | spd.nr_pages++; | |
1164 | break; | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | if (!spd.nr_pages) | |
1169 | return 0; | |
1170 | ||
1171 | ret = *nonpad_ret = splice_to_pipe(pipe, &spd); | |
1172 | if (ret < 0 || ret < total_len) | |
1173 | return ret; | |
1174 | ||
1175 | if (read_start + ret == nonpad_end) | |
1176 | ret += padding; | |
1177 | ||
1178 | return ret; | |
1179 | } | |
1180 | ||
1181 | static ssize_t relay_file_splice_read(struct file *in, | |
1182 | loff_t *ppos, | |
1183 | struct pipe_inode_info *pipe, | |
1184 | size_t len, | |
1185 | unsigned int flags) | |
1186 | { | |
1187 | ssize_t spliced; | |
1188 | int ret; | |
1189 | int nonpad_ret = 0; | |
1190 | ||
1191 | ret = 0; | |
1192 | spliced = 0; | |
1193 | ||
1194 | while (len && !spliced) { | |
1195 | ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret); | |
1196 | if (ret < 0) | |
1197 | break; | |
1198 | else if (!ret) { | |
1199 | if (spliced) | |
1200 | break; | |
1201 | if (flags & SPLICE_F_NONBLOCK) { | |
1202 | ret = -EAGAIN; | |
1203 | break; | |
1204 | } | |
1205 | } | |
1206 | ||
1207 | *ppos += ret; | |
1208 | if (ret > len) | |
1209 | len = 0; | |
1210 | else | |
1211 | len -= ret; | |
1212 | spliced += nonpad_ret; | |
1213 | nonpad_ret = 0; | |
1214 | } | |
1215 | ||
1216 | if (spliced) | |
1217 | return spliced; | |
1218 | ||
1219 | return ret; | |
1220 | } | |
1221 | ||
1222 | const struct file_operations relay_file_operations = { | |
1223 | .open = relay_file_open, | |
1224 | .poll = relay_file_poll, | |
1225 | .mmap = relay_file_mmap, | |
1226 | .read = relay_file_read, | |
1227 | .llseek = no_llseek, | |
1228 | .release = relay_file_release, | |
1229 | .splice_read = relay_file_splice_read, | |
1230 | }; | |
1231 | EXPORT_SYMBOL_GPL(relay_file_operations); | |
1232 | ||
1233 | static __init int relay_init(void) | |
1234 | { | |
1235 | ||
1236 | hotcpu_notifier(relay_hotcpu_callback, 0); | |
1237 | return 0; | |
1238 | } | |
1239 | ||
1240 | module_init(relay_init); |