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e1152c37 PMF |
1 | /* |
2 | * Public API and common code for kernel->userspace relay file support. | |
3 | * | |
4 | * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp | |
5 | * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com) | |
6 | * Copyright (C) 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) | |
7 | * | |
8 | * Moved to kernel/relay.c by Paul Mundt, 2006. | |
9 | * November 2006 - CPU hotplug support by Mathieu Desnoyers | |
10 | * (mathieu.desnoyers@polymtl.ca) | |
11 | * | |
12 | * This file is released under the GPL. | |
13 | */ | |
5f54827b PMF |
14 | //ust// #include <linux/errno.h> |
15 | //ust// #include <linux/stddef.h> | |
16 | //ust// #include <linux/slab.h> | |
17 | //ust// #include <linux/module.h> | |
18 | //ust// #include <linux/string.h> | |
19 | //ust// #include <linux/ltt-relay.h> | |
20 | //ust// #include <linux/vmalloc.h> | |
21 | //ust// #include <linux/mm.h> | |
22 | //ust// #include <linux/cpu.h> | |
23 | //ust// #include <linux/splice.h> | |
24 | //ust// #include <linux/bitops.h> | |
25 | #include <sys/mman.h> | |
26 | #include "kernelcompat.h" | |
27 | #include "list.h" | |
28 | #include "relay.h" | |
29 | #include "channels.h" | |
30 | #include "kref.h" | |
e1152c37 PMF |
31 | |
32 | /* list of open channels, for cpu hotplug */ | |
33 | static DEFINE_MUTEX(relay_channels_mutex); | |
34 | static LIST_HEAD(relay_channels); | |
35 | ||
36 | /** | |
37 | * relay_alloc_buf - allocate a channel buffer | |
38 | * @buf: the buffer struct | |
39 | * @size: total size of the buffer | |
40 | */ | |
5f54827b PMF |
41 | //ust// static int relay_alloc_buf(struct rchan_buf *buf, size_t *size) |
42 | //ust//{ | |
43 | //ust// unsigned int i, n_pages; | |
44 | //ust// struct buf_page *buf_page, *n; | |
45 | //ust// | |
46 | //ust// *size = PAGE_ALIGN(*size); | |
47 | //ust// n_pages = *size >> PAGE_SHIFT; | |
48 | //ust// | |
49 | //ust// INIT_LIST_HEAD(&buf->pages); | |
50 | //ust// | |
51 | //ust// for (i = 0; i < n_pages; i++) { | |
52 | //ust// buf_page = kmalloc_node(sizeof(*buf_page), GFP_KERNEL, | |
53 | //ust// cpu_to_node(buf->cpu)); | |
54 | //ust// if (unlikely(!buf_page)) | |
55 | //ust// goto depopulate; | |
56 | //ust// buf_page->page = alloc_pages_node(cpu_to_node(buf->cpu), | |
57 | //ust// GFP_KERNEL | __GFP_ZERO, 0); | |
58 | //ust// if (unlikely(!buf_page->page)) { | |
59 | //ust// kfree(buf_page); | |
60 | //ust// goto depopulate; | |
61 | //ust// } | |
62 | //ust// list_add_tail(&buf_page->list, &buf->pages); | |
63 | //ust// buf_page->offset = (size_t)i << PAGE_SHIFT; | |
64 | //ust// buf_page->buf = buf; | |
65 | //ust// set_page_private(buf_page->page, (unsigned long)buf_page); | |
66 | //ust// if (i == 0) { | |
67 | //ust// buf->wpage = buf_page; | |
68 | //ust// buf->hpage[0] = buf_page; | |
69 | //ust// buf->hpage[1] = buf_page; | |
70 | //ust// buf->rpage = buf_page; | |
71 | //ust// } | |
72 | //ust// } | |
73 | //ust// buf->page_count = n_pages; | |
74 | //ust// return 0; | |
75 | //ust// | |
76 | //ust//depopulate: | |
77 | //ust// list_for_each_entry_safe(buf_page, n, &buf->pages, list) { | |
78 | //ust// list_del_init(&buf_page->list); | |
79 | //ust// __free_page(buf_page->page); | |
80 | //ust// kfree(buf_page); | |
81 | //ust// } | |
82 | //ust// return -ENOMEM; | |
83 | //ust//} | |
84 | ||
e1152c37 PMF |
85 | static int relay_alloc_buf(struct rchan_buf *buf, size_t *size) |
86 | { | |
5f54827b | 87 | unsigned int n_pages; |
e1152c37 PMF |
88 | struct buf_page *buf_page, *n; |
89 | ||
5f54827b PMF |
90 | void *result; |
91 | ||
e1152c37 | 92 | *size = PAGE_ALIGN(*size); |
e1152c37 | 93 | |
5f54827b PMF |
94 | /* Maybe do read-ahead */ |
95 | result = mmap(NULL, *size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS, -1, 0); | |
96 | if(result == MAP_FAILED) { | |
97 | PERROR("mmap"); | |
98 | return -1; | |
e1152c37 | 99 | } |
5f54827b PMF |
100 | |
101 | buf->buf_data = result; | |
102 | buf->buf_size = *size; | |
103 | ||
104 | return 0; | |
e1152c37 PMF |
105 | } |
106 | ||
107 | /** | |
108 | * relay_create_buf - allocate and initialize a channel buffer | |
109 | * @chan: the relay channel | |
110 | * @cpu: cpu the buffer belongs to | |
111 | * | |
112 | * Returns channel buffer if successful, %NULL otherwise. | |
113 | */ | |
114 | static struct rchan_buf *relay_create_buf(struct rchan *chan, int cpu) | |
115 | { | |
116 | int ret; | |
117 | struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL); | |
118 | if (!buf) | |
119 | return NULL; | |
120 | ||
5f54827b | 121 | // buf->cpu = cpu; |
e1152c37 PMF |
122 | ret = relay_alloc_buf(buf, &chan->alloc_size); |
123 | if (ret) | |
124 | goto free_buf; | |
125 | ||
126 | buf->chan = chan; | |
127 | kref_get(&buf->chan->kref); | |
128 | return buf; | |
129 | ||
130 | free_buf: | |
131 | kfree(buf); | |
132 | return NULL; | |
133 | } | |
134 | ||
135 | /** | |
136 | * relay_destroy_channel - free the channel struct | |
137 | * @kref: target kernel reference that contains the relay channel | |
138 | * | |
139 | * Should only be called from kref_put(). | |
140 | */ | |
141 | static void relay_destroy_channel(struct kref *kref) | |
142 | { | |
143 | struct rchan *chan = container_of(kref, struct rchan, kref); | |
144 | kfree(chan); | |
145 | } | |
146 | ||
147 | /** | |
148 | * relay_destroy_buf - destroy an rchan_buf struct and associated buffer | |
149 | * @buf: the buffer struct | |
150 | */ | |
151 | static void relay_destroy_buf(struct rchan_buf *buf) | |
152 | { | |
153 | struct rchan *chan = buf->chan; | |
154 | struct buf_page *buf_page, *n; | |
5f54827b | 155 | int result; |
e1152c37 | 156 | |
5f54827b PMF |
157 | result = munmap(buf->buf_data, buf->buf_size); |
158 | if(result == -1) { | |
159 | PERROR("munmap"); | |
160 | ||
161 | //ust// chan->buf[buf->cpu] = NULL; | |
e1152c37 PMF |
162 | kfree(buf); |
163 | kref_put(&chan->kref, relay_destroy_channel); | |
164 | } | |
165 | ||
166 | /** | |
167 | * relay_remove_buf - remove a channel buffer | |
168 | * @kref: target kernel reference that contains the relay buffer | |
169 | * | |
170 | * Removes the file from the fileystem, which also frees the | |
171 | * rchan_buf_struct and the channel buffer. Should only be called from | |
172 | * kref_put(). | |
173 | */ | |
174 | static void relay_remove_buf(struct kref *kref) | |
175 | { | |
176 | struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); | |
177 | buf->chan->cb->remove_buf_file(buf->dentry); | |
178 | relay_destroy_buf(buf); | |
179 | } | |
180 | ||
181 | /* | |
182 | * High-level relay kernel API and associated functions. | |
183 | */ | |
184 | ||
185 | /* | |
186 | * rchan_callback implementations defining default channel behavior. Used | |
187 | * in place of corresponding NULL values in client callback struct. | |
188 | */ | |
189 | ||
190 | /* | |
191 | * create_buf_file_create() default callback. Does nothing. | |
192 | */ | |
193 | static struct dentry *create_buf_file_default_callback(const char *filename, | |
194 | struct dentry *parent, | |
195 | int mode, | |
196 | struct rchan_buf *buf) | |
197 | { | |
198 | return NULL; | |
199 | } | |
200 | ||
201 | /* | |
202 | * remove_buf_file() default callback. Does nothing. | |
203 | */ | |
204 | static int remove_buf_file_default_callback(struct dentry *dentry) | |
205 | { | |
206 | return -EINVAL; | |
207 | } | |
208 | ||
209 | /* relay channel default callbacks */ | |
210 | static struct rchan_callbacks default_channel_callbacks = { | |
211 | .create_buf_file = create_buf_file_default_callback, | |
212 | .remove_buf_file = remove_buf_file_default_callback, | |
213 | }; | |
214 | ||
215 | /** | |
216 | * wakeup_readers - wake up readers waiting on a channel | |
217 | * @data: contains the channel buffer | |
218 | * | |
219 | * This is the timer function used to defer reader waking. | |
220 | */ | |
221 | static void wakeup_readers(unsigned long data) | |
222 | { | |
223 | struct rchan_buf *buf = (struct rchan_buf *)data; | |
224 | wake_up_interruptible(&buf->read_wait); | |
225 | } | |
226 | ||
227 | /** | |
228 | * __relay_reset - reset a channel buffer | |
229 | * @buf: the channel buffer | |
230 | * @init: 1 if this is a first-time initialization | |
231 | * | |
232 | * See relay_reset() for description of effect. | |
233 | */ | |
234 | static void __relay_reset(struct rchan_buf *buf, unsigned int init) | |
235 | { | |
236 | if (init) { | |
237 | init_waitqueue_head(&buf->read_wait); | |
238 | kref_init(&buf->kref); | |
239 | setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf); | |
240 | } else | |
241 | del_timer_sync(&buf->timer); | |
242 | ||
243 | buf->finalized = 0; | |
244 | } | |
245 | ||
246 | /* | |
247 | * relay_open_buf - create a new relay channel buffer | |
248 | * | |
249 | * used by relay_open() and CPU hotplug. | |
250 | */ | |
251 | static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) | |
252 | { | |
253 | struct rchan_buf *buf = NULL; | |
254 | struct dentry *dentry; | |
255 | char *tmpname; | |
256 | ||
257 | tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL); | |
258 | if (!tmpname) | |
259 | goto end; | |
260 | snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu); | |
261 | ||
262 | buf = relay_create_buf(chan, cpu); | |
263 | if (!buf) | |
264 | goto free_name; | |
265 | ||
266 | __relay_reset(buf, 1); | |
267 | ||
268 | /* Create file in fs */ | |
5f54827b PMF |
269 | //ust// dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, |
270 | //ust// buf); | |
271 | //ust// if (!dentry) | |
272 | //ust// goto free_buf; | |
273 | //ust// | |
274 | //ust// buf->dentry = dentry; | |
e1152c37 PMF |
275 | |
276 | goto free_name; | |
277 | ||
278 | free_buf: | |
279 | relay_destroy_buf(buf); | |
280 | buf = NULL; | |
281 | free_name: | |
282 | kfree(tmpname); | |
283 | end: | |
284 | return buf; | |
285 | } | |
286 | ||
287 | /** | |
288 | * relay_close_buf - close a channel buffer | |
289 | * @buf: channel buffer | |
290 | * | |
291 | * Marks the buffer finalized and restores the default callbacks. | |
292 | * The channel buffer and channel buffer data structure are then freed | |
293 | * automatically when the last reference is given up. | |
294 | */ | |
295 | static void relay_close_buf(struct rchan_buf *buf) | |
296 | { | |
297 | del_timer_sync(&buf->timer); | |
298 | kref_put(&buf->kref, relay_remove_buf); | |
299 | } | |
300 | ||
301 | static void setup_callbacks(struct rchan *chan, | |
302 | struct rchan_callbacks *cb) | |
303 | { | |
304 | if (!cb) { | |
305 | chan->cb = &default_channel_callbacks; | |
306 | return; | |
307 | } | |
308 | ||
309 | if (!cb->create_buf_file) | |
310 | cb->create_buf_file = create_buf_file_default_callback; | |
311 | if (!cb->remove_buf_file) | |
312 | cb->remove_buf_file = remove_buf_file_default_callback; | |
313 | chan->cb = cb; | |
314 | } | |
315 | ||
316 | /** | |
317 | * relay_hotcpu_callback - CPU hotplug callback | |
318 | * @nb: notifier block | |
319 | * @action: hotplug action to take | |
320 | * @hcpu: CPU number | |
321 | * | |
322 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
323 | */ | |
5f54827b PMF |
324 | //ust// static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb, |
325 | //ust// unsigned long action, | |
326 | //ust// void *hcpu) | |
327 | //ust// { | |
328 | //ust// unsigned int hotcpu = (unsigned long)hcpu; | |
329 | //ust// struct rchan *chan; | |
330 | //ust// | |
331 | //ust// switch (action) { | |
332 | //ust// case CPU_UP_PREPARE: | |
333 | //ust// case CPU_UP_PREPARE_FROZEN: | |
334 | //ust// mutex_lock(&relay_channels_mutex); | |
335 | //ust// list_for_each_entry(chan, &relay_channels, list) { | |
336 | //ust// if (chan->buf[hotcpu]) | |
337 | //ust// continue; | |
338 | //ust// chan->buf[hotcpu] = relay_open_buf(chan, hotcpu); | |
339 | //ust// if (!chan->buf[hotcpu]) { | |
340 | //ust// printk(KERN_ERR | |
341 | //ust// "relay_hotcpu_callback: cpu %d buffer " | |
342 | //ust// "creation failed\n", hotcpu); | |
343 | //ust// mutex_unlock(&relay_channels_mutex); | |
344 | //ust// return NOTIFY_BAD; | |
345 | //ust// } | |
346 | //ust// } | |
347 | //ust// mutex_unlock(&relay_channels_mutex); | |
348 | //ust// break; | |
349 | //ust// case CPU_DEAD: | |
350 | //ust// case CPU_DEAD_FROZEN: | |
351 | //ust// /* No need to flush the cpu : will be flushed upon | |
352 | //ust// * final relay_flush() call. */ | |
353 | //ust// break; | |
354 | //ust// } | |
355 | //ust// return NOTIFY_OK; | |
356 | //ust// } | |
e1152c37 PMF |
357 | |
358 | /** | |
359 | * ltt_relay_open - create a new relay channel | |
360 | * @base_filename: base name of files to create | |
361 | * @parent: dentry of parent directory, %NULL for root directory | |
362 | * @subbuf_size: size of sub-buffers | |
363 | * @n_subbufs: number of sub-buffers | |
364 | * @cb: client callback functions | |
365 | * @private_data: user-defined data | |
366 | * | |
367 | * Returns channel pointer if successful, %NULL otherwise. | |
368 | * | |
369 | * Creates a channel buffer for each cpu using the sizes and | |
370 | * attributes specified. The created channel buffer files | |
371 | * will be named base_filename0...base_filenameN-1. File | |
372 | * permissions will be %S_IRUSR. | |
373 | */ | |
374 | struct rchan *ltt_relay_open(const char *base_filename, | |
375 | struct dentry *parent, | |
376 | size_t subbuf_size, | |
377 | size_t n_subbufs, | |
378 | struct rchan_callbacks *cb, | |
379 | void *private_data) | |
380 | { | |
381 | unsigned int i; | |
382 | struct rchan *chan; | |
383 | if (!base_filename) | |
384 | return NULL; | |
385 | ||
386 | if (!(subbuf_size && n_subbufs)) | |
387 | return NULL; | |
388 | ||
389 | chan = kzalloc(sizeof(struct rchan), GFP_KERNEL); | |
390 | if (!chan) | |
391 | return NULL; | |
392 | ||
393 | chan->version = LTT_RELAY_CHANNEL_VERSION; | |
394 | chan->n_subbufs = n_subbufs; | |
395 | chan->subbuf_size = subbuf_size; | |
396 | chan->subbuf_size_order = get_count_order(subbuf_size); | |
397 | chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); | |
398 | chan->parent = parent; | |
399 | chan->private_data = private_data; | |
400 | strlcpy(chan->base_filename, base_filename, NAME_MAX); | |
401 | setup_callbacks(chan, cb); | |
402 | kref_init(&chan->kref); | |
403 | ||
404 | mutex_lock(&relay_channels_mutex); | |
405 | for_each_online_cpu(i) { | |
406 | chan->buf[i] = relay_open_buf(chan, i); | |
407 | if (!chan->buf[i]) | |
408 | goto free_bufs; | |
409 | } | |
410 | list_add(&chan->list, &relay_channels); | |
411 | mutex_unlock(&relay_channels_mutex); | |
412 | ||
413 | return chan; | |
414 | ||
415 | free_bufs: | |
416 | for_each_possible_cpu(i) { | |
417 | if (!chan->buf[i]) | |
418 | break; | |
419 | relay_close_buf(chan->buf[i]); | |
420 | } | |
421 | ||
422 | kref_put(&chan->kref, relay_destroy_channel); | |
423 | mutex_unlock(&relay_channels_mutex); | |
424 | return NULL; | |
425 | } | |
426 | EXPORT_SYMBOL_GPL(ltt_relay_open); | |
427 | ||
428 | /** | |
429 | * ltt_relay_close - close the channel | |
430 | * @chan: the channel | |
431 | * | |
432 | * Closes all channel buffers and frees the channel. | |
433 | */ | |
434 | void ltt_relay_close(struct rchan *chan) | |
435 | { | |
436 | unsigned int i; | |
437 | ||
438 | if (!chan) | |
439 | return; | |
440 | ||
441 | mutex_lock(&relay_channels_mutex); | |
442 | for_each_possible_cpu(i) | |
443 | if (chan->buf[i]) | |
444 | relay_close_buf(chan->buf[i]); | |
445 | ||
446 | list_del(&chan->list); | |
447 | kref_put(&chan->kref, relay_destroy_channel); | |
448 | mutex_unlock(&relay_channels_mutex); | |
449 | } | |
450 | EXPORT_SYMBOL_GPL(ltt_relay_close); | |
451 | ||
452 | /* | |
453 | * Start iteration at the previous element. Skip the real list head. | |
454 | */ | |
455 | struct buf_page *ltt_relay_find_prev_page(struct rchan_buf *buf, | |
456 | struct buf_page *page, size_t offset, ssize_t diff_offset) | |
457 | { | |
458 | struct buf_page *iter; | |
459 | size_t orig_iter_off; | |
460 | unsigned int i = 0; | |
461 | ||
462 | orig_iter_off = page->offset; | |
463 | list_for_each_entry_reverse(iter, &page->list, list) { | |
464 | /* | |
465 | * Skip the real list head. | |
466 | */ | |
467 | if (&iter->list == &buf->pages) | |
468 | continue; | |
469 | i++; | |
470 | if (offset >= iter->offset | |
471 | && offset < iter->offset + PAGE_SIZE) { | |
472 | #ifdef CONFIG_LTT_RELAY_CHECK_RANDOM_ACCESS | |
473 | if (i > 1) { | |
474 | printk(KERN_WARNING | |
475 | "Backward random access detected in " | |
476 | "ltt_relay. Iterations %u, " | |
477 | "offset %zu, orig iter->off %zu, " | |
478 | "iter->off %zu diff_offset %zd.\n", i, | |
479 | offset, orig_iter_off, iter->offset, | |
480 | diff_offset); | |
481 | WARN_ON(1); | |
482 | } | |
483 | #endif | |
484 | return iter; | |
485 | } | |
486 | } | |
487 | WARN_ON(1); | |
488 | return NULL; | |
489 | } | |
490 | EXPORT_SYMBOL_GPL(ltt_relay_find_prev_page); | |
491 | ||
492 | /* | |
493 | * Start iteration at the next element. Skip the real list head. | |
494 | */ | |
495 | struct buf_page *ltt_relay_find_next_page(struct rchan_buf *buf, | |
496 | struct buf_page *page, size_t offset, ssize_t diff_offset) | |
497 | { | |
498 | struct buf_page *iter; | |
499 | unsigned int i = 0; | |
500 | size_t orig_iter_off; | |
501 | ||
502 | orig_iter_off = page->offset; | |
503 | list_for_each_entry(iter, &page->list, list) { | |
504 | /* | |
505 | * Skip the real list head. | |
506 | */ | |
507 | if (&iter->list == &buf->pages) | |
508 | continue; | |
509 | i++; | |
510 | if (offset >= iter->offset | |
511 | && offset < iter->offset + PAGE_SIZE) { | |
512 | #ifdef CONFIG_LTT_RELAY_CHECK_RANDOM_ACCESS | |
513 | if (i > 1) { | |
514 | printk(KERN_WARNING | |
515 | "Forward random access detected in " | |
516 | "ltt_relay. Iterations %u, " | |
517 | "offset %zu, orig iter->off %zu, " | |
518 | "iter->off %zu diff_offset %zd.\n", i, | |
519 | offset, orig_iter_off, iter->offset, | |
520 | diff_offset); | |
521 | WARN_ON(1); | |
522 | } | |
523 | #endif | |
524 | return iter; | |
525 | } | |
526 | } | |
527 | WARN_ON(1); | |
528 | return NULL; | |
529 | } | |
530 | EXPORT_SYMBOL_GPL(ltt_relay_find_next_page); | |
531 | ||
532 | /** | |
533 | * ltt_relay_write - write data to a ltt_relay buffer. | |
534 | * @buf : buffer | |
535 | * @offset : offset within the buffer | |
536 | * @src : source address | |
537 | * @len : length to write | |
538 | * @page : cached buffer page | |
539 | * @pagecpy : page size copied so far | |
540 | */ | |
541 | void _ltt_relay_write(struct rchan_buf *buf, size_t offset, | |
542 | const void *src, size_t len, struct buf_page *page, ssize_t pagecpy) | |
543 | { | |
544 | do { | |
545 | len -= pagecpy; | |
546 | src += pagecpy; | |
547 | offset += pagecpy; | |
548 | /* | |
549 | * Underlying layer should never ask for writes across | |
550 | * subbuffers. | |
551 | */ | |
552 | WARN_ON(offset >= buf->chan->alloc_size); | |
553 | ||
554 | page = ltt_relay_cache_page(buf, &buf->wpage, page, offset); | |
555 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
556 | ltt_relay_do_copy(page_address(page->page) | |
557 | + (offset & ~PAGE_MASK), src, pagecpy); | |
558 | } while (unlikely(len != pagecpy)); | |
559 | } | |
560 | EXPORT_SYMBOL_GPL(_ltt_relay_write); | |
561 | ||
562 | /** | |
563 | * ltt_relay_read - read data from ltt_relay_buffer. | |
564 | * @buf : buffer | |
565 | * @offset : offset within the buffer | |
566 | * @dest : destination address | |
567 | * @len : length to write | |
568 | */ | |
569 | int ltt_relay_read(struct rchan_buf *buf, size_t offset, | |
570 | void *dest, size_t len) | |
571 | { | |
572 | struct buf_page *page; | |
573 | ssize_t pagecpy, orig_len; | |
574 | ||
575 | orig_len = len; | |
576 | offset &= buf->chan->alloc_size - 1; | |
577 | page = buf->rpage; | |
578 | if (unlikely(!len)) | |
579 | return 0; | |
580 | for (;;) { | |
581 | page = ltt_relay_cache_page(buf, &buf->rpage, page, offset); | |
582 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
583 | memcpy(dest, page_address(page->page) + (offset & ~PAGE_MASK), | |
584 | pagecpy); | |
585 | len -= pagecpy; | |
586 | if (likely(!len)) | |
587 | break; | |
588 | dest += pagecpy; | |
589 | offset += pagecpy; | |
590 | /* | |
591 | * Underlying layer should never ask for reads across | |
592 | * subbuffers. | |
593 | */ | |
594 | WARN_ON(offset >= buf->chan->alloc_size); | |
595 | } | |
596 | return orig_len; | |
597 | } | |
598 | EXPORT_SYMBOL_GPL(ltt_relay_read); | |
599 | ||
600 | /** | |
601 | * ltt_relay_read_get_page - Get a whole page to read from | |
602 | * @buf : buffer | |
603 | * @offset : offset within the buffer | |
604 | */ | |
5f54827b PMF |
605 | //ust// struct buf_page *ltt_relay_read_get_page(struct rchan_buf *buf, size_t offset) |
606 | //ust// { | |
607 | //ust// struct buf_page *page; | |
e1152c37 | 608 | |
5f54827b PMF |
609 | //ust// offset &= buf->chan->alloc_size - 1; |
610 | //ust// page = buf->rpage; | |
611 | //ust// page = ltt_relay_cache_page(buf, &buf->rpage, page, offset); | |
612 | //ust// return page; | |
613 | //ust// } | |
614 | //ust// EXPORT_SYMBOL_GPL(ltt_relay_read_get_page); | |
e1152c37 PMF |
615 | |
616 | /** | |
617 | * ltt_relay_offset_address - get address of a location within the buffer | |
618 | * @buf : buffer | |
619 | * @offset : offset within the buffer. | |
620 | * | |
621 | * Return the address where a given offset is located. | |
622 | * Should be used to get the current subbuffer header pointer. Given we know | |
623 | * it's never on a page boundary, it's safe to write directly to this address, | |
624 | * as long as the write is never bigger than a page size. | |
625 | */ | |
626 | void *ltt_relay_offset_address(struct rchan_buf *buf, size_t offset) | |
627 | { | |
628 | struct buf_page *page; | |
629 | unsigned int odd; | |
630 | ||
631 | offset &= buf->chan->alloc_size - 1; | |
632 | odd = !!(offset & buf->chan->subbuf_size); | |
633 | page = buf->hpage[odd]; | |
634 | if (offset < page->offset || offset >= page->offset + PAGE_SIZE) | |
635 | buf->hpage[odd] = page = buf->wpage; | |
636 | page = ltt_relay_cache_page(buf, &buf->hpage[odd], page, offset); | |
637 | return page_address(page->page) + (offset & ~PAGE_MASK); | |
638 | } | |
5f54827b | 639 | //ust// EXPORT_SYMBOL_GPL(ltt_relay_offset_address); |
e1152c37 PMF |
640 | |
641 | /** | |
642 | * relay_file_open - open file op for relay files | |
643 | * @inode: the inode | |
644 | * @filp: the file | |
645 | * | |
646 | * Increments the channel buffer refcount. | |
647 | */ | |
5f54827b PMF |
648 | //ust// static int relay_file_open(struct inode *inode, struct file *filp) |
649 | //ust// { | |
650 | //ust// struct rchan_buf *buf = inode->i_private; | |
651 | //ust// kref_get(&buf->kref); | |
652 | //ust// filp->private_data = buf; | |
653 | //ust// | |
654 | //ust// return nonseekable_open(inode, filp); | |
655 | //ust// } | |
e1152c37 PMF |
656 | |
657 | /** | |
658 | * relay_file_release - release file op for relay files | |
659 | * @inode: the inode | |
660 | * @filp: the file | |
661 | * | |
662 | * Decrements the channel refcount, as the filesystem is | |
663 | * no longer using it. | |
664 | */ | |
665 | static int relay_file_release(struct inode *inode, struct file *filp) | |
666 | { | |
667 | struct rchan_buf *buf = filp->private_data; | |
668 | kref_put(&buf->kref, relay_remove_buf); | |
669 | ||
670 | return 0; | |
671 | } | |
672 | ||
5f54827b PMF |
673 | //ust// const struct file_operations ltt_relay_file_operations = { |
674 | //ust// .open = relay_file_open, | |
675 | //ust// .release = relay_file_release, | |
676 | //ust// }; | |
677 | //ust// EXPORT_SYMBOL_GPL(ltt_relay_file_operations); | |
e1152c37 | 678 | |
5f54827b PMF |
679 | //ust// static __init int relay_init(void) |
680 | //ust// { | |
681 | //ust// hotcpu_notifier(relay_hotcpu_callback, 5); | |
682 | //ust// return 0; | |
683 | //ust// } | |
e1152c37 | 684 | |
5f54827b | 685 | //ust// module_init(relay_init); |