Commit | Line | Data |
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355b0502 GKH |
1 | /* |
2 | * drivers/misc/logger.c | |
3 | * | |
4 | * A Logging Subsystem | |
5 | * | |
6 | * Copyright (C) 2007-2008 Google, Inc. | |
7 | * | |
8 | * Robert Love <rlove@google.com> | |
9 | * | |
10 | * This software is licensed under the terms of the GNU General Public | |
11 | * License version 2, as published by the Free Software Foundation, and | |
12 | * may be copied, distributed, and modified under those terms. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | */ | |
19 | ||
c810a399 SK |
20 | #define pr_fmt(fmt) "logger: " fmt |
21 | ||
23687af9 | 22 | #include <linux/sched.h> |
355b0502 GKH |
23 | #include <linux/module.h> |
24 | #include <linux/fs.h> | |
25 | #include <linux/miscdevice.h> | |
26 | #include <linux/uaccess.h> | |
27 | #include <linux/poll.h> | |
c11a166c | 28 | #include <linux/slab.h> |
355b0502 | 29 | #include <linux/time.h> |
10b24199 | 30 | #include <linux/vmalloc.h> |
355b0502 GKH |
31 | #include "logger.h" |
32 | ||
33 | #include <asm/ioctls.h> | |
34 | ||
0edc6c6d | 35 | /** |
355b0502 | 36 | * struct logger_log - represents a specific log, such as 'main' or 'radio' |
0edc6c6d CJB |
37 | * @buffer: The actual ring buffer |
38 | * @misc: The "misc" device representing the log | |
39 | * @wq: The wait queue for @readers | |
40 | * @readers: This log's readers | |
41 | * @mutex: The mutex that protects the @buffer | |
42 | * @w_off: The current write head offset | |
43 | * @head: The head, or location that readers start reading at. | |
44 | * @size: The size of the log | |
45 | * @logs: The list of log channels | |
355b0502 GKH |
46 | * |
47 | * This structure lives from module insertion until module removal, so it does | |
48 | * not need additional reference counting. The structure is protected by the | |
49 | * mutex 'mutex'. | |
50 | */ | |
51 | struct logger_log { | |
0edc6c6d CJB |
52 | unsigned char *buffer; |
53 | struct miscdevice misc; | |
54 | wait_queue_head_t wq; | |
55 | struct list_head readers; | |
56 | struct mutex mutex; | |
57 | size_t w_off; | |
58 | size_t head; | |
59 | size_t size; | |
60 | struct list_head logs; | |
355b0502 GKH |
61 | }; |
62 | ||
10b24199 TB |
63 | static LIST_HEAD(log_list); |
64 | ||
65 | ||
0edc6c6d | 66 | /** |
355b0502 | 67 | * struct logger_reader - a logging device open for reading |
0edc6c6d CJB |
68 | * @log: The associated log |
69 | * @list: The associated entry in @logger_log's list | |
70 | * @r_off: The current read head offset. | |
355b0502 GKH |
71 | * |
72 | * This object lives from open to release, so we don't need additional | |
73 | * reference counting. The structure is protected by log->mutex. | |
74 | */ | |
75 | struct logger_reader { | |
0edc6c6d CJB |
76 | struct logger_log *log; |
77 | struct list_head list; | |
78 | size_t r_off; | |
355b0502 GKH |
79 | }; |
80 | ||
81 | /* logger_offset - returns index 'n' into the log via (optimized) modulus */ | |
e7f3eb0c | 82 | static size_t logger_offset(struct logger_log *log, size_t n) |
c626224d | 83 | { |
e7f3eb0c | 84 | return n & (log->size - 1); |
c626224d TB |
85 | } |
86 | ||
355b0502 GKH |
87 | |
88 | /* | |
89 | * file_get_log - Given a file structure, return the associated log | |
90 | * | |
91 | * This isn't aesthetic. We have several goals: | |
92 | * | |
277cdd01 MN |
93 | * 1) Need to quickly obtain the associated log during an I/O operation |
94 | * 2) Readers need to maintain state (logger_reader) | |
95 | * 3) Writers need to be very fast (open() should be a near no-op) | |
355b0502 GKH |
96 | * |
97 | * In the reader case, we can trivially go file->logger_reader->logger_log. | |
98 | * For a writer, we don't want to maintain a logger_reader, so we just go | |
99 | * file->logger_log. Thus what file->private_data points at depends on whether | |
100 | * or not the file was opened for reading. This function hides that dirtiness. | |
101 | */ | |
102 | static inline struct logger_log *file_get_log(struct file *file) | |
103 | { | |
104 | if (file->f_mode & FMODE_READ) { | |
105 | struct logger_reader *reader = file->private_data; | |
106 | return reader->log; | |
107 | } else | |
108 | return file->private_data; | |
109 | } | |
110 | ||
111 | /* | |
112 | * get_entry_len - Grabs the length of the payload of the next entry starting | |
113 | * from 'off'. | |
114 | * | |
3bcfa431 TB |
115 | * An entry length is 2 bytes (16 bits) in host endian order. |
116 | * In the log, the length does not include the size of the log entry structure. | |
117 | * This function returns the size including the log entry structure. | |
118 | * | |
355b0502 GKH |
119 | * Caller needs to hold log->mutex. |
120 | */ | |
121 | static __u32 get_entry_len(struct logger_log *log, size_t off) | |
122 | { | |
123 | __u16 val; | |
124 | ||
3bcfa431 TB |
125 | /* copy 2 bytes from buffer, in memcpy order, */ |
126 | /* handling possible wrap at end of buffer */ | |
127 | ||
128 | ((__u8 *)&val)[0] = log->buffer[off]; | |
129 | if (likely(off+1 < log->size)) | |
130 | ((__u8 *)&val)[1] = log->buffer[off+1]; | |
131 | else | |
132 | ((__u8 *)&val)[1] = log->buffer[0]; | |
355b0502 GKH |
133 | |
134 | return sizeof(struct logger_entry) + val; | |
135 | } | |
136 | ||
137 | /* | |
138 | * do_read_log_to_user - reads exactly 'count' bytes from 'log' into the | |
139 | * user-space buffer 'buf'. Returns 'count' on success. | |
140 | * | |
141 | * Caller must hold log->mutex. | |
142 | */ | |
143 | static ssize_t do_read_log_to_user(struct logger_log *log, | |
144 | struct logger_reader *reader, | |
145 | char __user *buf, | |
146 | size_t count) | |
147 | { | |
148 | size_t len; | |
149 | ||
150 | /* | |
151 | * We read from the log in two disjoint operations. First, we read from | |
152 | * the current read head offset up to 'count' bytes or to the end of | |
153 | * the log, whichever comes first. | |
154 | */ | |
155 | len = min(count, log->size - reader->r_off); | |
156 | if (copy_to_user(buf, log->buffer + reader->r_off, len)) | |
157 | return -EFAULT; | |
158 | ||
159 | /* | |
160 | * Second, we read any remaining bytes, starting back at the head of | |
161 | * the log. | |
162 | */ | |
163 | if (count != len) | |
164 | if (copy_to_user(buf + len, log->buffer, count - len)) | |
165 | return -EFAULT; | |
166 | ||
c626224d | 167 | reader->r_off = logger_offset(log, reader->r_off + count); |
355b0502 GKH |
168 | |
169 | return count; | |
170 | } | |
171 | ||
172 | /* | |
173 | * logger_read - our log's read() method | |
174 | * | |
175 | * Behavior: | |
176 | * | |
277cdd01 MN |
177 | * - O_NONBLOCK works |
178 | * - If there are no log entries to read, blocks until log is written to | |
179 | * - Atomically reads exactly one log entry | |
355b0502 GKH |
180 | * |
181 | * Optimal read size is LOGGER_ENTRY_MAX_LEN. Will set errno to EINVAL if read | |
182 | * buffer is insufficient to hold next entry. | |
183 | */ | |
184 | static ssize_t logger_read(struct file *file, char __user *buf, | |
185 | size_t count, loff_t *pos) | |
186 | { | |
187 | struct logger_reader *reader = file->private_data; | |
188 | struct logger_log *log = reader->log; | |
189 | ssize_t ret; | |
190 | DEFINE_WAIT(wait); | |
191 | ||
192 | start: | |
193 | while (1) { | |
c76c7ca3 TB |
194 | mutex_lock(&log->mutex); |
195 | ||
355b0502 GKH |
196 | prepare_to_wait(&log->wq, &wait, TASK_INTERRUPTIBLE); |
197 | ||
355b0502 GKH |
198 | ret = (log->w_off == reader->r_off); |
199 | mutex_unlock(&log->mutex); | |
200 | if (!ret) | |
201 | break; | |
202 | ||
203 | if (file->f_flags & O_NONBLOCK) { | |
204 | ret = -EAGAIN; | |
205 | break; | |
206 | } | |
207 | ||
208 | if (signal_pending(current)) { | |
209 | ret = -EINTR; | |
210 | break; | |
211 | } | |
212 | ||
213 | schedule(); | |
214 | } | |
215 | ||
216 | finish_wait(&log->wq, &wait); | |
217 | if (ret) | |
218 | return ret; | |
219 | ||
220 | mutex_lock(&log->mutex); | |
221 | ||
222 | /* is there still something to read or did we race? */ | |
223 | if (unlikely(log->w_off == reader->r_off)) { | |
224 | mutex_unlock(&log->mutex); | |
225 | goto start; | |
226 | } | |
227 | ||
228 | /* get the size of the next entry */ | |
229 | ret = get_entry_len(log, reader->r_off); | |
230 | if (count < ret) { | |
231 | ret = -EINVAL; | |
232 | goto out; | |
233 | } | |
234 | ||
235 | /* get exactly one entry from the log */ | |
236 | ret = do_read_log_to_user(log, reader, buf, ret); | |
237 | ||
238 | out: | |
239 | mutex_unlock(&log->mutex); | |
240 | ||
241 | return ret; | |
242 | } | |
243 | ||
244 | /* | |
245 | * get_next_entry - return the offset of the first valid entry at least 'len' | |
246 | * bytes after 'off'. | |
247 | * | |
248 | * Caller must hold log->mutex. | |
249 | */ | |
250 | static size_t get_next_entry(struct logger_log *log, size_t off, size_t len) | |
251 | { | |
252 | size_t count = 0; | |
253 | ||
254 | do { | |
255 | size_t nr = get_entry_len(log, off); | |
c626224d | 256 | off = logger_offset(log, off + nr); |
355b0502 GKH |
257 | count += nr; |
258 | } while (count < len); | |
259 | ||
260 | return off; | |
261 | } | |
262 | ||
263 | /* | |
169c843a TB |
264 | * is_between - is a < c < b, accounting for wrapping of a, b, and c |
265 | * positions in the buffer | |
266 | * | |
267 | * That is, if a<b, check for c between a and b | |
268 | * and if a>b, check for c outside (not between) a and b | |
269 | * | |
270 | * |------- a xxxxxxxx b --------| | |
271 | * c^ | |
272 | * | |
273 | * |xxxxx b --------- a xxxxxxxxx| | |
274 | * c^ | |
275 | * or c^ | |
355b0502 | 276 | */ |
169c843a | 277 | static inline int is_between(size_t a, size_t b, size_t c) |
355b0502 | 278 | { |
169c843a TB |
279 | if (a < b) { |
280 | /* is c between a and b? */ | |
281 | if (a < c && c <= b) | |
355b0502 GKH |
282 | return 1; |
283 | } else { | |
169c843a TB |
284 | /* is c outside of b through a? */ |
285 | if (c <= b || a < c) | |
355b0502 GKH |
286 | return 1; |
287 | } | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | /* | |
293 | * fix_up_readers - walk the list of all readers and "fix up" any who were | |
294 | * lapped by the writer; also do the same for the default "start head". | |
295 | * We do this by "pulling forward" the readers and start head to the first | |
296 | * entry after the new write head. | |
297 | * | |
298 | * The caller needs to hold log->mutex. | |
299 | */ | |
300 | static void fix_up_readers(struct logger_log *log, size_t len) | |
301 | { | |
302 | size_t old = log->w_off; | |
c626224d | 303 | size_t new = logger_offset(log, old + len); |
355b0502 GKH |
304 | struct logger_reader *reader; |
305 | ||
169c843a | 306 | if (is_between(old, new, log->head)) |
355b0502 GKH |
307 | log->head = get_next_entry(log, log->head, len); |
308 | ||
309 | list_for_each_entry(reader, &log->readers, list) | |
169c843a | 310 | if (is_between(old, new, reader->r_off)) |
355b0502 GKH |
311 | reader->r_off = get_next_entry(log, reader->r_off, len); |
312 | } | |
313 | ||
314 | /* | |
315 | * do_write_log - writes 'len' bytes from 'buf' to 'log' | |
316 | * | |
317 | * The caller needs to hold log->mutex. | |
318 | */ | |
319 | static void do_write_log(struct logger_log *log, const void *buf, size_t count) | |
320 | { | |
321 | size_t len; | |
322 | ||
323 | len = min(count, log->size - log->w_off); | |
324 | memcpy(log->buffer + log->w_off, buf, len); | |
325 | ||
326 | if (count != len) | |
327 | memcpy(log->buffer, buf + len, count - len); | |
328 | ||
c626224d | 329 | log->w_off = logger_offset(log, log->w_off + count); |
355b0502 GKH |
330 | |
331 | } | |
332 | ||
333 | /* | |
334 | * do_write_log_user - writes 'len' bytes from the user-space buffer 'buf' to | |
335 | * the log 'log' | |
336 | * | |
337 | * The caller needs to hold log->mutex. | |
338 | * | |
339 | * Returns 'count' on success, negative error code on failure. | |
340 | */ | |
341 | static ssize_t do_write_log_from_user(struct logger_log *log, | |
342 | const void __user *buf, size_t count) | |
343 | { | |
344 | size_t len; | |
345 | ||
346 | len = min(count, log->size - log->w_off); | |
347 | if (len && copy_from_user(log->buffer + log->w_off, buf, len)) | |
348 | return -EFAULT; | |
349 | ||
350 | if (count != len) | |
351 | if (copy_from_user(log->buffer, buf + len, count - len)) | |
350a1955 TB |
352 | /* |
353 | * Note that by not updating w_off, this abandons the | |
354 | * portion of the new entry that *was* successfully | |
355 | * copied, just above. This is intentional to avoid | |
356 | * message corruption from missing fragments. | |
357 | */ | |
355b0502 GKH |
358 | return -EFAULT; |
359 | ||
c626224d | 360 | log->w_off = logger_offset(log, log->w_off + count); |
355b0502 GKH |
361 | |
362 | return count; | |
363 | } | |
364 | ||
365 | /* | |
366 | * logger_aio_write - our write method, implementing support for write(), | |
367 | * writev(), and aio_write(). Writes are our fast path, and we try to optimize | |
368 | * them above all else. | |
369 | */ | |
e7f3eb0c | 370 | static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, |
355b0502 GKH |
371 | unsigned long nr_segs, loff_t ppos) |
372 | { | |
373 | struct logger_log *log = file_get_log(iocb->ki_filp); | |
374 | size_t orig = log->w_off; | |
375 | struct logger_entry header; | |
376 | struct timespec now; | |
377 | ssize_t ret = 0; | |
378 | ||
379 | now = current_kernel_time(); | |
380 | ||
381 | header.pid = current->tgid; | |
382 | header.tid = current->pid; | |
383 | header.sec = now.tv_sec; | |
384 | header.nsec = now.tv_nsec; | |
385 | header.len = min_t(size_t, iocb->ki_left, LOGGER_ENTRY_MAX_PAYLOAD); | |
386 | ||
387 | /* null writes succeed, return zero */ | |
388 | if (unlikely(!header.len)) | |
389 | return 0; | |
390 | ||
391 | mutex_lock(&log->mutex); | |
392 | ||
393 | /* | |
394 | * Fix up any readers, pulling them forward to the first readable | |
395 | * entry after (what will be) the new write offset. We do this now | |
396 | * because if we partially fail, we can end up with clobbered log | |
397 | * entries that encroach on readable buffer. | |
398 | */ | |
399 | fix_up_readers(log, sizeof(struct logger_entry) + header.len); | |
400 | ||
401 | do_write_log(log, &header, sizeof(struct logger_entry)); | |
402 | ||
403 | while (nr_segs-- > 0) { | |
404 | size_t len; | |
405 | ssize_t nr; | |
406 | ||
407 | /* figure out how much of this vector we can keep */ | |
408 | len = min_t(size_t, iov->iov_len, header.len - ret); | |
409 | ||
410 | /* write out this segment's payload */ | |
411 | nr = do_write_log_from_user(log, iov->iov_base, len); | |
412 | if (unlikely(nr < 0)) { | |
413 | log->w_off = orig; | |
414 | mutex_unlock(&log->mutex); | |
415 | return nr; | |
416 | } | |
417 | ||
418 | iov++; | |
419 | ret += nr; | |
420 | } | |
421 | ||
422 | mutex_unlock(&log->mutex); | |
423 | ||
424 | /* wake up any blocked readers */ | |
425 | wake_up_interruptible(&log->wq); | |
426 | ||
427 | return ret; | |
428 | } | |
429 | ||
10b24199 TB |
430 | static struct logger_log *get_log_from_minor(int minor) |
431 | { | |
432 | struct logger_log *log; | |
433 | ||
434 | list_for_each_entry(log, &log_list, logs) | |
435 | if (log->misc.minor == minor) | |
436 | return log; | |
437 | return NULL; | |
438 | } | |
355b0502 GKH |
439 | |
440 | /* | |
441 | * logger_open - the log's open() file operation | |
442 | * | |
443 | * Note how near a no-op this is in the write-only case. Keep it that way! | |
444 | */ | |
445 | static int logger_open(struct inode *inode, struct file *file) | |
446 | { | |
447 | struct logger_log *log; | |
448 | int ret; | |
449 | ||
450 | ret = nonseekable_open(inode, file); | |
451 | if (ret) | |
452 | return ret; | |
453 | ||
454 | log = get_log_from_minor(MINOR(inode->i_rdev)); | |
455 | if (!log) | |
456 | return -ENODEV; | |
457 | ||
458 | if (file->f_mode & FMODE_READ) { | |
459 | struct logger_reader *reader; | |
460 | ||
461 | reader = kmalloc(sizeof(struct logger_reader), GFP_KERNEL); | |
462 | if (!reader) | |
463 | return -ENOMEM; | |
464 | ||
465 | reader->log = log; | |
466 | INIT_LIST_HEAD(&reader->list); | |
467 | ||
468 | mutex_lock(&log->mutex); | |
469 | reader->r_off = log->head; | |
470 | list_add_tail(&reader->list, &log->readers); | |
471 | mutex_unlock(&log->mutex); | |
472 | ||
473 | file->private_data = reader; | |
474 | } else | |
475 | file->private_data = log; | |
476 | ||
477 | return 0; | |
478 | } | |
479 | ||
480 | /* | |
481 | * logger_release - the log's release file operation | |
482 | * | |
483 | * Note this is a total no-op in the write-only case. Keep it that way! | |
484 | */ | |
485 | static int logger_release(struct inode *ignored, struct file *file) | |
486 | { | |
487 | if (file->f_mode & FMODE_READ) { | |
488 | struct logger_reader *reader = file->private_data; | |
47de87a2 RV |
489 | struct logger_log *log = reader->log; |
490 | ||
491 | mutex_lock(&log->mutex); | |
355b0502 | 492 | list_del(&reader->list); |
47de87a2 RV |
493 | mutex_unlock(&log->mutex); |
494 | ||
355b0502 GKH |
495 | kfree(reader); |
496 | } | |
497 | ||
498 | return 0; | |
499 | } | |
500 | ||
501 | /* | |
502 | * logger_poll - the log's poll file operation, for poll/select/epoll | |
503 | * | |
504 | * Note we always return POLLOUT, because you can always write() to the log. | |
505 | * Note also that, strictly speaking, a return value of POLLIN does not | |
506 | * guarantee that the log is readable without blocking, as there is a small | |
507 | * chance that the writer can lap the reader in the interim between poll() | |
508 | * returning and the read() request. | |
509 | */ | |
510 | static unsigned int logger_poll(struct file *file, poll_table *wait) | |
511 | { | |
512 | struct logger_reader *reader; | |
513 | struct logger_log *log; | |
514 | unsigned int ret = POLLOUT | POLLWRNORM; | |
515 | ||
516 | if (!(file->f_mode & FMODE_READ)) | |
517 | return ret; | |
518 | ||
519 | reader = file->private_data; | |
520 | log = reader->log; | |
521 | ||
522 | poll_wait(file, &log->wq, wait); | |
523 | ||
524 | mutex_lock(&log->mutex); | |
525 | if (log->w_off != reader->r_off) | |
526 | ret |= POLLIN | POLLRDNORM; | |
527 | mutex_unlock(&log->mutex); | |
528 | ||
529 | return ret; | |
530 | } | |
531 | ||
532 | static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
533 | { | |
534 | struct logger_log *log = file_get_log(file); | |
535 | struct logger_reader *reader; | |
536 | long ret = -ENOTTY; | |
537 | ||
538 | mutex_lock(&log->mutex); | |
539 | ||
540 | switch (cmd) { | |
541 | case LOGGER_GET_LOG_BUF_SIZE: | |
542 | ret = log->size; | |
543 | break; | |
544 | case LOGGER_GET_LOG_LEN: | |
545 | if (!(file->f_mode & FMODE_READ)) { | |
546 | ret = -EBADF; | |
547 | break; | |
548 | } | |
549 | reader = file->private_data; | |
550 | if (log->w_off >= reader->r_off) | |
551 | ret = log->w_off - reader->r_off; | |
552 | else | |
553 | ret = (log->size - reader->r_off) + log->w_off; | |
554 | break; | |
555 | case LOGGER_GET_NEXT_ENTRY_LEN: | |
556 | if (!(file->f_mode & FMODE_READ)) { | |
557 | ret = -EBADF; | |
558 | break; | |
559 | } | |
560 | reader = file->private_data; | |
561 | if (log->w_off != reader->r_off) | |
562 | ret = get_entry_len(log, reader->r_off); | |
563 | else | |
564 | ret = 0; | |
565 | break; | |
566 | case LOGGER_FLUSH_LOG: | |
567 | if (!(file->f_mode & FMODE_WRITE)) { | |
568 | ret = -EBADF; | |
569 | break; | |
570 | } | |
571 | list_for_each_entry(reader, &log->readers, list) | |
572 | reader->r_off = log->w_off; | |
573 | log->head = log->w_off; | |
574 | ret = 0; | |
575 | break; | |
576 | } | |
577 | ||
578 | mutex_unlock(&log->mutex); | |
579 | ||
580 | return ret; | |
581 | } | |
582 | ||
583 | static const struct file_operations logger_fops = { | |
584 | .owner = THIS_MODULE, | |
585 | .read = logger_read, | |
586 | .aio_write = logger_aio_write, | |
587 | .poll = logger_poll, | |
588 | .unlocked_ioctl = logger_ioctl, | |
589 | .compat_ioctl = logger_ioctl, | |
590 | .open = logger_open, | |
591 | .release = logger_release, | |
592 | }; | |
593 | ||
594 | /* | |
10b24199 TB |
595 | * Log size must be a power of two, greater than LOGGER_ENTRY_MAX_LEN, |
596 | * and less than LONG_MAX minus LOGGER_ENTRY_MAX_LEN. | |
355b0502 | 597 | */ |
10b24199 TB |
598 | static int __init create_log(char *log_name, int size) |
599 | { | |
600 | int ret = 0; | |
601 | struct logger_log *log; | |
602 | unsigned char *buffer; | |
355b0502 | 603 | |
10b24199 TB |
604 | buffer = vmalloc(size); |
605 | if (buffer == NULL) | |
606 | return -ENOMEM; | |
355b0502 | 607 | |
10b24199 TB |
608 | log = kzalloc(sizeof(struct logger_log), GFP_KERNEL); |
609 | if (log == NULL) { | |
610 | ret = -ENOMEM; | |
611 | goto out_free_buffer; | |
612 | } | |
613 | log->buffer = buffer; | |
355b0502 | 614 | |
10b24199 TB |
615 | log->misc.minor = MISC_DYNAMIC_MINOR; |
616 | log->misc.name = kstrdup(log_name, GFP_KERNEL); | |
617 | if (log->misc.name == NULL) { | |
618 | ret = -ENOMEM; | |
619 | goto out_free_log; | |
620 | } | |
621 | ||
622 | log->misc.fops = &logger_fops; | |
623 | log->misc.parent = NULL; | |
355b0502 | 624 | |
10b24199 TB |
625 | init_waitqueue_head(&log->wq); |
626 | INIT_LIST_HEAD(&log->readers); | |
627 | mutex_init(&log->mutex); | |
628 | log->w_off = 0; | |
629 | log->head = 0; | |
630 | log->size = size; | |
631 | ||
632 | INIT_LIST_HEAD(&log->logs); | |
633 | list_add_tail(&log->logs, &log_list); | |
634 | ||
635 | /* finally, initialize the misc device for this log */ | |
355b0502 GKH |
636 | ret = misc_register(&log->misc); |
637 | if (unlikely(ret)) { | |
c810a399 SK |
638 | pr_err("failed to register misc device for log '%s'!\n", |
639 | log->misc.name); | |
10b24199 | 640 | goto out_free_log; |
355b0502 GKH |
641 | } |
642 | ||
c810a399 SK |
643 | pr_info("created %luK log '%s'\n", |
644 | (unsigned long) log->size >> 10, log->misc.name); | |
355b0502 GKH |
645 | |
646 | return 0; | |
10b24199 TB |
647 | |
648 | out_free_log: | |
649 | kfree(log); | |
650 | ||
651 | out_free_buffer: | |
652 | vfree(buffer); | |
653 | return ret; | |
355b0502 GKH |
654 | } |
655 | ||
656 | static int __init logger_init(void) | |
657 | { | |
658 | int ret; | |
659 | ||
10b24199 | 660 | ret = create_log(LOGGER_LOG_MAIN, 256*1024); |
355b0502 GKH |
661 | if (unlikely(ret)) |
662 | goto out; | |
663 | ||
10b24199 | 664 | ret = create_log(LOGGER_LOG_EVENTS, 256*1024); |
355b0502 GKH |
665 | if (unlikely(ret)) |
666 | goto out; | |
667 | ||
10b24199 | 668 | ret = create_log(LOGGER_LOG_RADIO, 256*1024); |
355b0502 GKH |
669 | if (unlikely(ret)) |
670 | goto out; | |
671 | ||
10b24199 | 672 | ret = create_log(LOGGER_LOG_SYSTEM, 256*1024); |
3537cdaa SM |
673 | if (unlikely(ret)) |
674 | goto out; | |
675 | ||
355b0502 GKH |
676 | out: |
677 | return ret; | |
678 | } | |
679 | device_initcall(logger_init); |