Commit | Line | Data |
---|---|---|
2056a782 | 1 | /* |
0fe23479 | 2 | * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> |
2056a782 JA |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program; if not, write to the Free Software | |
15 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | * | |
17 | */ | |
2056a782 JA |
18 | #include <linux/kernel.h> |
19 | #include <linux/blkdev.h> | |
20 | #include <linux/blktrace_api.h> | |
21 | #include <linux/percpu.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/mutex.h> | |
24 | #include <linux/debugfs.h> | |
be1c6341 | 25 | #include <linux/time.h> |
2056a782 JA |
26 | #include <asm/uaccess.h> |
27 | ||
28 | static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, }; | |
29 | static unsigned int blktrace_seq __read_mostly = 1; | |
30 | ||
be1c6341 OK |
31 | /* |
32 | * Send out a notify message. | |
33 | */ | |
a863055b JA |
34 | static void trace_note(struct blk_trace *bt, pid_t pid, int action, |
35 | const void *data, size_t len) | |
be1c6341 OK |
36 | { |
37 | struct blk_io_trace *t; | |
be1c6341 OK |
38 | |
39 | t = relay_reserve(bt->rchan, sizeof(*t) + len); | |
d3d9d2a5 JA |
40 | if (t) { |
41 | const int cpu = smp_processor_id(); | |
42 | ||
43 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
7c2ff389 | 44 | t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); |
d3d9d2a5 JA |
45 | t->device = bt->dev; |
46 | t->action = action; | |
47 | t->pid = pid; | |
48 | t->cpu = cpu; | |
49 | t->pdu_len = len; | |
50 | memcpy((void *) t + sizeof(*t), data, len); | |
51 | } | |
be1c6341 OK |
52 | } |
53 | ||
2056a782 JA |
54 | /* |
55 | * Send out a notify for this process, if we haven't done so since a trace | |
56 | * started | |
57 | */ | |
58 | static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) | |
59 | { | |
a863055b JA |
60 | tsk->btrace_seq = blktrace_seq; |
61 | trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); | |
be1c6341 | 62 | } |
2056a782 | 63 | |
be1c6341 OK |
64 | static void trace_note_time(struct blk_trace *bt) |
65 | { | |
66 | struct timespec now; | |
67 | unsigned long flags; | |
68 | u32 words[2]; | |
69 | ||
70 | getnstimeofday(&now); | |
71 | words[0] = now.tv_sec; | |
72 | words[1] = now.tv_nsec; | |
73 | ||
74 | local_irq_save(flags); | |
75 | trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); | |
76 | local_irq_restore(flags); | |
2056a782 JA |
77 | } |
78 | ||
79 | static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, | |
80 | pid_t pid) | |
81 | { | |
82 | if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) | |
83 | return 1; | |
84 | if (sector < bt->start_lba || sector > bt->end_lba) | |
85 | return 1; | |
86 | if (bt->pid && pid != bt->pid) | |
87 | return 1; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | /* | |
93 | * Data direction bit lookup | |
94 | */ | |
95 | static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; | |
96 | ||
97 | /* | |
98 | * Bio action bits of interest | |
99 | */ | |
7457e6e2 | 100 | static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) }; |
2056a782 JA |
101 | |
102 | /* | |
103 | * More could be added as needed, taking care to increment the decrementer | |
104 | * to get correct indexing | |
105 | */ | |
106 | #define trace_barrier_bit(rw) \ | |
107 | (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0)) | |
108 | #define trace_sync_bit(rw) \ | |
109 | (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1)) | |
40359ccb | 110 | #define trace_ahead_bit(rw) \ |
ad01b1ca | 111 | (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD)) |
7457e6e2 JA |
112 | #define trace_meta_bit(rw) \ |
113 | (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3)) | |
2056a782 JA |
114 | |
115 | /* | |
116 | * The worker for the various blk_add_trace*() types. Fills out a | |
117 | * blk_io_trace structure and places it in a per-cpu subbuffer. | |
118 | */ | |
119 | void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, | |
120 | int rw, u32 what, int error, int pdu_len, void *pdu_data) | |
121 | { | |
122 | struct task_struct *tsk = current; | |
123 | struct blk_io_trace *t; | |
124 | unsigned long flags; | |
125 | unsigned long *sequence; | |
126 | pid_t pid; | |
127 | int cpu; | |
128 | ||
129 | if (unlikely(bt->trace_state != Blktrace_running)) | |
130 | return; | |
131 | ||
132 | what |= ddir_act[rw & WRITE]; | |
133 | what |= bio_act[trace_barrier_bit(rw)]; | |
134 | what |= bio_act[trace_sync_bit(rw)]; | |
40359ccb | 135 | what |= bio_act[trace_ahead_bit(rw)]; |
7457e6e2 | 136 | what |= bio_act[trace_meta_bit(rw)]; |
2056a782 JA |
137 | |
138 | pid = tsk->pid; | |
139 | if (unlikely(act_log_check(bt, what, sector, pid))) | |
140 | return; | |
141 | ||
142 | /* | |
143 | * A word about the locking here - we disable interrupts to reserve | |
144 | * some space in the relay per-cpu buffer, to prevent an irq | |
145 | * from coming in and stepping on our toes. Once reserved, it's | |
146 | * enough to get preemption disabled to prevent read of this data | |
147 | * before we are through filling it. get_cpu()/put_cpu() does this | |
148 | * for us | |
149 | */ | |
150 | local_irq_save(flags); | |
151 | ||
152 | if (unlikely(tsk->btrace_seq != blktrace_seq)) | |
153 | trace_note_tsk(bt, tsk); | |
154 | ||
155 | t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); | |
156 | if (t) { | |
157 | cpu = smp_processor_id(); | |
158 | sequence = per_cpu_ptr(bt->sequence, cpu); | |
159 | ||
160 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
161 | t->sequence = ++(*sequence); | |
7c2ff389 | 162 | t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); |
2056a782 JA |
163 | t->sector = sector; |
164 | t->bytes = bytes; | |
165 | t->action = what; | |
166 | t->pid = pid; | |
167 | t->device = bt->dev; | |
168 | t->cpu = cpu; | |
169 | t->error = error; | |
170 | t->pdu_len = pdu_len; | |
171 | ||
172 | if (pdu_len) | |
173 | memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); | |
174 | } | |
175 | ||
176 | local_irq_restore(flags); | |
177 | } | |
178 | ||
179 | EXPORT_SYMBOL_GPL(__blk_add_trace); | |
180 | ||
181 | static struct dentry *blk_tree_root; | |
182 | static struct mutex blk_tree_mutex; | |
183 | static unsigned int root_users; | |
184 | ||
185 | static inline void blk_remove_root(void) | |
186 | { | |
187 | if (blk_tree_root) { | |
188 | debugfs_remove(blk_tree_root); | |
189 | blk_tree_root = NULL; | |
190 | } | |
191 | } | |
192 | ||
193 | static void blk_remove_tree(struct dentry *dir) | |
194 | { | |
195 | mutex_lock(&blk_tree_mutex); | |
196 | debugfs_remove(dir); | |
197 | if (--root_users == 0) | |
198 | blk_remove_root(); | |
199 | mutex_unlock(&blk_tree_mutex); | |
200 | } | |
201 | ||
202 | static struct dentry *blk_create_tree(const char *blk_name) | |
203 | { | |
204 | struct dentry *dir = NULL; | |
35fc51e7 | 205 | int created = 0; |
2056a782 JA |
206 | |
207 | mutex_lock(&blk_tree_mutex); | |
208 | ||
209 | if (!blk_tree_root) { | |
210 | blk_tree_root = debugfs_create_dir("block", NULL); | |
211 | if (!blk_tree_root) | |
212 | goto err; | |
35fc51e7 | 213 | created = 1; |
2056a782 JA |
214 | } |
215 | ||
216 | dir = debugfs_create_dir(blk_name, blk_tree_root); | |
217 | if (dir) | |
218 | root_users++; | |
35fc51e7 AK |
219 | else { |
220 | /* Delete root only if we created it */ | |
221 | if (created) | |
222 | blk_remove_root(); | |
223 | } | |
2056a782 JA |
224 | |
225 | err: | |
226 | mutex_unlock(&blk_tree_mutex); | |
227 | return dir; | |
228 | } | |
229 | ||
230 | static void blk_trace_cleanup(struct blk_trace *bt) | |
231 | { | |
232 | relay_close(bt->rchan); | |
233 | debugfs_remove(bt->dropped_file); | |
234 | blk_remove_tree(bt->dir); | |
235 | free_percpu(bt->sequence); | |
236 | kfree(bt); | |
237 | } | |
238 | ||
165125e1 | 239 | static int blk_trace_remove(struct request_queue *q) |
2056a782 JA |
240 | { |
241 | struct blk_trace *bt; | |
242 | ||
243 | bt = xchg(&q->blk_trace, NULL); | |
244 | if (!bt) | |
245 | return -EINVAL; | |
246 | ||
247 | if (bt->trace_state == Blktrace_setup || | |
248 | bt->trace_state == Blktrace_stopped) | |
249 | blk_trace_cleanup(bt); | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | static int blk_dropped_open(struct inode *inode, struct file *filp) | |
255 | { | |
8e18e294 | 256 | filp->private_data = inode->i_private; |
2056a782 JA |
257 | |
258 | return 0; | |
259 | } | |
260 | ||
261 | static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, | |
262 | size_t count, loff_t *ppos) | |
263 | { | |
264 | struct blk_trace *bt = filp->private_data; | |
265 | char buf[16]; | |
266 | ||
267 | snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); | |
268 | ||
269 | return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); | |
270 | } | |
271 | ||
2b8693c0 | 272 | static const struct file_operations blk_dropped_fops = { |
2056a782 JA |
273 | .owner = THIS_MODULE, |
274 | .open = blk_dropped_open, | |
275 | .read = blk_dropped_read, | |
276 | }; | |
277 | ||
278 | /* | |
279 | * Keep track of how many times we encountered a full subbuffer, to aid | |
280 | * the user space app in telling how many lost events there were. | |
281 | */ | |
282 | static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, | |
283 | void *prev_subbuf, size_t prev_padding) | |
284 | { | |
285 | struct blk_trace *bt; | |
286 | ||
287 | if (!relay_buf_full(buf)) | |
288 | return 1; | |
289 | ||
290 | bt = buf->chan->private_data; | |
291 | atomic_inc(&bt->dropped); | |
292 | return 0; | |
293 | } | |
294 | ||
295 | static int blk_remove_buf_file_callback(struct dentry *dentry) | |
296 | { | |
297 | debugfs_remove(dentry); | |
298 | return 0; | |
299 | } | |
300 | ||
301 | static struct dentry *blk_create_buf_file_callback(const char *filename, | |
302 | struct dentry *parent, | |
303 | int mode, | |
304 | struct rchan_buf *buf, | |
305 | int *is_global) | |
306 | { | |
307 | return debugfs_create_file(filename, mode, parent, buf, | |
308 | &relay_file_operations); | |
309 | } | |
310 | ||
311 | static struct rchan_callbacks blk_relay_callbacks = { | |
312 | .subbuf_start = blk_subbuf_start_callback, | |
313 | .create_buf_file = blk_create_buf_file_callback, | |
314 | .remove_buf_file = blk_remove_buf_file_callback, | |
315 | }; | |
316 | ||
317 | /* | |
318 | * Setup everything required to start tracing | |
319 | */ | |
171044d4 AB |
320 | int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev, |
321 | struct blk_user_trace_setup *buts) | |
2056a782 | 322 | { |
2056a782 JA |
323 | struct blk_trace *old_bt, *bt = NULL; |
324 | struct dentry *dir = NULL; | |
325 | char b[BDEVNAME_SIZE]; | |
326 | int ret, i; | |
327 | ||
171044d4 | 328 | if (!buts->buf_size || !buts->buf_nr) |
2056a782 JA |
329 | return -EINVAL; |
330 | ||
171044d4 | 331 | strcpy(buts->name, bdevname(bdev, b)); |
2056a782 JA |
332 | |
333 | /* | |
334 | * some device names have larger paths - convert the slashes | |
335 | * to underscores for this to work as expected | |
336 | */ | |
171044d4 AB |
337 | for (i = 0; i < strlen(buts->name); i++) |
338 | if (buts->name[i] == '/') | |
339 | buts->name[i] = '_'; | |
2056a782 JA |
340 | |
341 | ret = -ENOMEM; | |
342 | bt = kzalloc(sizeof(*bt), GFP_KERNEL); | |
343 | if (!bt) | |
344 | goto err; | |
345 | ||
346 | bt->sequence = alloc_percpu(unsigned long); | |
347 | if (!bt->sequence) | |
348 | goto err; | |
349 | ||
350 | ret = -ENOENT; | |
171044d4 | 351 | dir = blk_create_tree(buts->name); |
2056a782 JA |
352 | if (!dir) |
353 | goto err; | |
354 | ||
355 | bt->dir = dir; | |
356 | bt->dev = bdev->bd_dev; | |
357 | atomic_set(&bt->dropped, 0); | |
358 | ||
359 | ret = -EIO; | |
360 | bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); | |
361 | if (!bt->dropped_file) | |
362 | goto err; | |
363 | ||
171044d4 AB |
364 | bt->rchan = relay_open("trace", dir, buts->buf_size, |
365 | buts->buf_nr, &blk_relay_callbacks, bt); | |
2056a782 JA |
366 | if (!bt->rchan) |
367 | goto err; | |
2056a782 | 368 | |
171044d4 | 369 | bt->act_mask = buts->act_mask; |
2056a782 JA |
370 | if (!bt->act_mask) |
371 | bt->act_mask = (u16) -1; | |
372 | ||
171044d4 AB |
373 | bt->start_lba = buts->start_lba; |
374 | bt->end_lba = buts->end_lba; | |
2056a782 JA |
375 | if (!bt->end_lba) |
376 | bt->end_lba = -1ULL; | |
377 | ||
171044d4 | 378 | bt->pid = buts->pid; |
2056a782 JA |
379 | bt->trace_state = Blktrace_setup; |
380 | ||
381 | ret = -EBUSY; | |
382 | old_bt = xchg(&q->blk_trace, bt); | |
383 | if (old_bt) { | |
384 | (void) xchg(&q->blk_trace, old_bt); | |
385 | goto err; | |
386 | } | |
387 | ||
388 | return 0; | |
389 | err: | |
390 | if (dir) | |
391 | blk_remove_tree(dir); | |
392 | if (bt) { | |
393 | if (bt->dropped_file) | |
394 | debugfs_remove(bt->dropped_file); | |
a1205868 | 395 | free_percpu(bt->sequence); |
2056a782 JA |
396 | if (bt->rchan) |
397 | relay_close(bt->rchan); | |
398 | kfree(bt); | |
399 | } | |
400 | return ret; | |
401 | } | |
171044d4 AB |
402 | |
403 | static int blk_trace_setup(struct request_queue *q, struct block_device *bdev, | |
404 | char __user *arg) | |
405 | { | |
406 | struct blk_user_trace_setup buts; | |
407 | int ret; | |
408 | ||
409 | ret = copy_from_user(&buts, arg, sizeof(buts)); | |
410 | if (ret) | |
411 | return -EFAULT; | |
412 | ||
413 | ret = do_blk_trace_setup(q, bdev, &buts); | |
414 | if (ret) | |
415 | return ret; | |
416 | ||
417 | if (copy_to_user(arg, &buts, sizeof(buts))) | |
418 | return -EFAULT; | |
419 | ||
420 | return 0; | |
421 | } | |
2056a782 | 422 | |
165125e1 | 423 | static int blk_trace_startstop(struct request_queue *q, int start) |
2056a782 JA |
424 | { |
425 | struct blk_trace *bt; | |
426 | int ret; | |
427 | ||
428 | if ((bt = q->blk_trace) == NULL) | |
429 | return -EINVAL; | |
430 | ||
431 | /* | |
432 | * For starting a trace, we can transition from a setup or stopped | |
433 | * trace. For stopping a trace, the state must be running | |
434 | */ | |
435 | ret = -EINVAL; | |
436 | if (start) { | |
437 | if (bt->trace_state == Blktrace_setup || | |
438 | bt->trace_state == Blktrace_stopped) { | |
439 | blktrace_seq++; | |
440 | smp_mb(); | |
441 | bt->trace_state = Blktrace_running; | |
be1c6341 OK |
442 | |
443 | trace_note_time(bt); | |
2056a782 JA |
444 | ret = 0; |
445 | } | |
446 | } else { | |
447 | if (bt->trace_state == Blktrace_running) { | |
448 | bt->trace_state = Blktrace_stopped; | |
449 | relay_flush(bt->rchan); | |
450 | ret = 0; | |
451 | } | |
452 | } | |
453 | ||
454 | return ret; | |
455 | } | |
456 | ||
457 | /** | |
458 | * blk_trace_ioctl: - handle the ioctls associated with tracing | |
459 | * @bdev: the block device | |
460 | * @cmd: the ioctl cmd | |
461 | * @arg: the argument data, if any | |
462 | * | |
463 | **/ | |
464 | int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) | |
465 | { | |
165125e1 | 466 | struct request_queue *q; |
2056a782 JA |
467 | int ret, start = 0; |
468 | ||
469 | q = bdev_get_queue(bdev); | |
470 | if (!q) | |
471 | return -ENXIO; | |
472 | ||
473 | mutex_lock(&bdev->bd_mutex); | |
474 | ||
475 | switch (cmd) { | |
476 | case BLKTRACESETUP: | |
477 | ret = blk_trace_setup(q, bdev, arg); | |
478 | break; | |
479 | case BLKTRACESTART: | |
480 | start = 1; | |
481 | case BLKTRACESTOP: | |
482 | ret = blk_trace_startstop(q, start); | |
483 | break; | |
484 | case BLKTRACETEARDOWN: | |
485 | ret = blk_trace_remove(q); | |
486 | break; | |
487 | default: | |
488 | ret = -ENOTTY; | |
489 | break; | |
490 | } | |
491 | ||
492 | mutex_unlock(&bdev->bd_mutex); | |
493 | return ret; | |
494 | } | |
495 | ||
496 | /** | |
497 | * blk_trace_shutdown: - stop and cleanup trace structures | |
498 | * @q: the request queue associated with the device | |
499 | * | |
500 | **/ | |
165125e1 | 501 | void blk_trace_shutdown(struct request_queue *q) |
2056a782 | 502 | { |
6c5c9341 AD |
503 | if (q->blk_trace) { |
504 | blk_trace_startstop(q, 0); | |
505 | blk_trace_remove(q); | |
506 | } | |
2056a782 JA |
507 | } |
508 | ||
509 | /* | |
7c2ff389 | 510 | * Average offset over two calls to cpu_clock() with a gettimeofday() |
2056a782 JA |
511 | * in the middle |
512 | */ | |
7c2ff389 | 513 | static void blk_check_time(unsigned long long *t, int this_cpu) |
2056a782 JA |
514 | { |
515 | unsigned long long a, b; | |
516 | struct timeval tv; | |
517 | ||
7c2ff389 | 518 | a = cpu_clock(this_cpu); |
2056a782 | 519 | do_gettimeofday(&tv); |
7c2ff389 | 520 | b = cpu_clock(this_cpu); |
2056a782 JA |
521 | |
522 | *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000; | |
523 | *t -= (a + b) / 2; | |
524 | } | |
525 | ||
4090959a MP |
526 | /* |
527 | * calibrate our inter-CPU timings | |
528 | */ | |
2056a782 JA |
529 | static void blk_trace_check_cpu_time(void *data) |
530 | { | |
531 | unsigned long long *t; | |
7c2ff389 | 532 | int this_cpu = get_cpu(); |
2056a782 | 533 | |
7c2ff389 | 534 | t = &per_cpu(blk_trace_cpu_offset, this_cpu); |
2056a782 JA |
535 | |
536 | /* | |
537 | * Just call it twice, hopefully the second call will be cache hot | |
538 | * and a little more precise | |
539 | */ | |
7c2ff389 IM |
540 | blk_check_time(t, this_cpu); |
541 | blk_check_time(t, this_cpu); | |
2056a782 JA |
542 | |
543 | put_cpu(); | |
544 | } | |
545 | ||
2056a782 JA |
546 | static void blk_trace_set_ht_offsets(void) |
547 | { | |
548 | #if defined(CONFIG_SCHED_SMT) | |
549 | int cpu, i; | |
550 | ||
551 | /* | |
552 | * now make sure HT siblings have the same time offset | |
553 | */ | |
554 | preempt_disable(); | |
555 | for_each_online_cpu(cpu) { | |
556 | unsigned long long *cpu_off, *sibling_off; | |
557 | ||
d5a7430d | 558 | for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu)) { |
2056a782 JA |
559 | if (i == cpu) |
560 | continue; | |
561 | ||
562 | cpu_off = &per_cpu(blk_trace_cpu_offset, cpu); | |
563 | sibling_off = &per_cpu(blk_trace_cpu_offset, i); | |
564 | *sibling_off = *cpu_off; | |
565 | } | |
566 | } | |
567 | preempt_enable(); | |
568 | #endif | |
569 | } | |
570 | ||
571 | static __init int blk_trace_init(void) | |
572 | { | |
573 | mutex_init(&blk_tree_mutex); | |
4090959a | 574 | on_each_cpu(blk_trace_check_cpu_time, NULL, 1, 1); |
2056a782 JA |
575 | blk_trace_set_ht_offsets(); |
576 | ||
577 | return 0; | |
578 | } | |
579 | ||
580 | module_init(blk_trace_init); | |
581 |