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 | ||
2056a782 JA |
28 | static unsigned int blktrace_seq __read_mostly = 1; |
29 | ||
be1c6341 OK |
30 | /* |
31 | * Send out a notify message. | |
32 | */ | |
a863055b JA |
33 | static void trace_note(struct blk_trace *bt, pid_t pid, int action, |
34 | const void *data, size_t len) | |
be1c6341 OK |
35 | { |
36 | struct blk_io_trace *t; | |
be1c6341 OK |
37 | |
38 | t = relay_reserve(bt->rchan, sizeof(*t) + len); | |
d3d9d2a5 JA |
39 | if (t) { |
40 | const int cpu = smp_processor_id(); | |
41 | ||
42 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
2997c8c4 | 43 | t->time = ktime_to_ns(ktime_get()); |
d3d9d2a5 JA |
44 | t->device = bt->dev; |
45 | t->action = action; | |
46 | t->pid = pid; | |
47 | t->cpu = cpu; | |
48 | t->pdu_len = len; | |
49 | memcpy((void *) t + sizeof(*t), data, len); | |
50 | } | |
be1c6341 OK |
51 | } |
52 | ||
2056a782 JA |
53 | /* |
54 | * Send out a notify for this process, if we haven't done so since a trace | |
55 | * started | |
56 | */ | |
57 | static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) | |
58 | { | |
a863055b JA |
59 | tsk->btrace_seq = blktrace_seq; |
60 | trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); | |
be1c6341 | 61 | } |
2056a782 | 62 | |
be1c6341 OK |
63 | static void trace_note_time(struct blk_trace *bt) |
64 | { | |
65 | struct timespec now; | |
66 | unsigned long flags; | |
67 | u32 words[2]; | |
68 | ||
69 | getnstimeofday(&now); | |
70 | words[0] = now.tv_sec; | |
71 | words[1] = now.tv_nsec; | |
72 | ||
73 | local_irq_save(flags); | |
74 | trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); | |
75 | local_irq_restore(flags); | |
2056a782 JA |
76 | } |
77 | ||
9d5f09a4 AB |
78 | void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) |
79 | { | |
80 | int n; | |
81 | va_list args; | |
14a73f54 | 82 | unsigned long flags; |
64565911 | 83 | char *buf; |
9d5f09a4 | 84 | |
14a73f54 | 85 | local_irq_save(flags); |
64565911 | 86 | buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); |
9d5f09a4 | 87 | va_start(args, fmt); |
64565911 | 88 | n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); |
9d5f09a4 AB |
89 | va_end(args); |
90 | ||
64565911 | 91 | trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); |
14a73f54 | 92 | local_irq_restore(flags); |
9d5f09a4 AB |
93 | } |
94 | EXPORT_SYMBOL_GPL(__trace_note_message); | |
95 | ||
2056a782 JA |
96 | static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, |
97 | pid_t pid) | |
98 | { | |
99 | if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) | |
100 | return 1; | |
101 | if (sector < bt->start_lba || sector > bt->end_lba) | |
102 | return 1; | |
103 | if (bt->pid && pid != bt->pid) | |
104 | return 1; | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | /* | |
110 | * Data direction bit lookup | |
111 | */ | |
112 | static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; | |
113 | ||
35ba8f70 DW |
114 | /* The ilog2() calls fall out because they're constant */ |
115 | #define MASK_TC_BIT(rw, __name) ( (rw & (1 << BIO_RW_ ## __name)) << \ | |
116 | (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name) ) | |
2056a782 JA |
117 | |
118 | /* | |
119 | * The worker for the various blk_add_trace*() types. Fills out a | |
120 | * blk_io_trace structure and places it in a per-cpu subbuffer. | |
121 | */ | |
122 | void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, | |
123 | int rw, u32 what, int error, int pdu_len, void *pdu_data) | |
124 | { | |
125 | struct task_struct *tsk = current; | |
126 | struct blk_io_trace *t; | |
127 | unsigned long flags; | |
128 | unsigned long *sequence; | |
129 | pid_t pid; | |
130 | int cpu; | |
131 | ||
132 | if (unlikely(bt->trace_state != Blktrace_running)) | |
133 | return; | |
134 | ||
135 | what |= ddir_act[rw & WRITE]; | |
35ba8f70 DW |
136 | what |= MASK_TC_BIT(rw, BARRIER); |
137 | what |= MASK_TC_BIT(rw, SYNC); | |
138 | what |= MASK_TC_BIT(rw, AHEAD); | |
139 | what |= MASK_TC_BIT(rw, META); | |
140 | what |= MASK_TC_BIT(rw, DISCARD); | |
2056a782 JA |
141 | |
142 | pid = tsk->pid; | |
143 | if (unlikely(act_log_check(bt, what, sector, pid))) | |
144 | return; | |
145 | ||
146 | /* | |
147 | * A word about the locking here - we disable interrupts to reserve | |
148 | * some space in the relay per-cpu buffer, to prevent an irq | |
14a73f54 | 149 | * from coming in and stepping on our toes. |
2056a782 JA |
150 | */ |
151 | local_irq_save(flags); | |
152 | ||
153 | if (unlikely(tsk->btrace_seq != blktrace_seq)) | |
154 | trace_note_tsk(bt, tsk); | |
155 | ||
156 | t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); | |
157 | if (t) { | |
158 | cpu = smp_processor_id(); | |
159 | sequence = per_cpu_ptr(bt->sequence, cpu); | |
160 | ||
161 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
162 | t->sequence = ++(*sequence); | |
2997c8c4 | 163 | t->time = ktime_to_ns(ktime_get()); |
2056a782 JA |
164 | t->sector = sector; |
165 | t->bytes = bytes; | |
166 | t->action = what; | |
167 | t->pid = pid; | |
168 | t->device = bt->dev; | |
169 | t->cpu = cpu; | |
170 | t->error = error; | |
171 | t->pdu_len = pdu_len; | |
172 | ||
173 | if (pdu_len) | |
174 | memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); | |
175 | } | |
176 | ||
177 | local_irq_restore(flags); | |
178 | } | |
179 | ||
180 | EXPORT_SYMBOL_GPL(__blk_add_trace); | |
181 | ||
182 | static struct dentry *blk_tree_root; | |
11a57153 | 183 | static DEFINE_MUTEX(blk_tree_mutex); |
2056a782 JA |
184 | static unsigned int root_users; |
185 | ||
186 | static inline void blk_remove_root(void) | |
187 | { | |
188 | if (blk_tree_root) { | |
189 | debugfs_remove(blk_tree_root); | |
190 | blk_tree_root = NULL; | |
191 | } | |
192 | } | |
193 | ||
194 | static void blk_remove_tree(struct dentry *dir) | |
195 | { | |
196 | mutex_lock(&blk_tree_mutex); | |
197 | debugfs_remove(dir); | |
198 | if (--root_users == 0) | |
199 | blk_remove_root(); | |
200 | mutex_unlock(&blk_tree_mutex); | |
201 | } | |
202 | ||
203 | static struct dentry *blk_create_tree(const char *blk_name) | |
204 | { | |
205 | struct dentry *dir = NULL; | |
35fc51e7 | 206 | int created = 0; |
2056a782 JA |
207 | |
208 | mutex_lock(&blk_tree_mutex); | |
209 | ||
210 | if (!blk_tree_root) { | |
211 | blk_tree_root = debugfs_create_dir("block", NULL); | |
212 | if (!blk_tree_root) | |
213 | goto err; | |
35fc51e7 | 214 | created = 1; |
2056a782 JA |
215 | } |
216 | ||
217 | dir = debugfs_create_dir(blk_name, blk_tree_root); | |
218 | if (dir) | |
219 | root_users++; | |
35fc51e7 AK |
220 | else { |
221 | /* Delete root only if we created it */ | |
222 | if (created) | |
223 | blk_remove_root(); | |
224 | } | |
2056a782 JA |
225 | |
226 | err: | |
227 | mutex_unlock(&blk_tree_mutex); | |
228 | return dir; | |
229 | } | |
230 | ||
231 | static void blk_trace_cleanup(struct blk_trace *bt) | |
232 | { | |
233 | relay_close(bt->rchan); | |
02c62304 | 234 | debugfs_remove(bt->msg_file); |
2056a782 JA |
235 | debugfs_remove(bt->dropped_file); |
236 | blk_remove_tree(bt->dir); | |
237 | free_percpu(bt->sequence); | |
64565911 | 238 | free_percpu(bt->msg_data); |
2056a782 JA |
239 | kfree(bt); |
240 | } | |
241 | ||
6da127ad | 242 | int blk_trace_remove(struct request_queue *q) |
2056a782 JA |
243 | { |
244 | struct blk_trace *bt; | |
245 | ||
246 | bt = xchg(&q->blk_trace, NULL); | |
247 | if (!bt) | |
248 | return -EINVAL; | |
249 | ||
250 | if (bt->trace_state == Blktrace_setup || | |
251 | bt->trace_state == Blktrace_stopped) | |
252 | blk_trace_cleanup(bt); | |
253 | ||
254 | return 0; | |
255 | } | |
6da127ad | 256 | EXPORT_SYMBOL_GPL(blk_trace_remove); |
2056a782 JA |
257 | |
258 | static int blk_dropped_open(struct inode *inode, struct file *filp) | |
259 | { | |
8e18e294 | 260 | filp->private_data = inode->i_private; |
2056a782 JA |
261 | |
262 | return 0; | |
263 | } | |
264 | ||
265 | static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, | |
266 | size_t count, loff_t *ppos) | |
267 | { | |
268 | struct blk_trace *bt = filp->private_data; | |
269 | char buf[16]; | |
270 | ||
271 | snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); | |
272 | ||
273 | return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); | |
274 | } | |
275 | ||
2b8693c0 | 276 | static const struct file_operations blk_dropped_fops = { |
2056a782 JA |
277 | .owner = THIS_MODULE, |
278 | .open = blk_dropped_open, | |
279 | .read = blk_dropped_read, | |
280 | }; | |
281 | ||
02c62304 AB |
282 | static int blk_msg_open(struct inode *inode, struct file *filp) |
283 | { | |
284 | filp->private_data = inode->i_private; | |
285 | ||
286 | return 0; | |
287 | } | |
288 | ||
289 | static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, | |
290 | size_t count, loff_t *ppos) | |
291 | { | |
292 | char *msg; | |
293 | struct blk_trace *bt; | |
294 | ||
295 | if (count > BLK_TN_MAX_MSG) | |
296 | return -EINVAL; | |
297 | ||
298 | msg = kmalloc(count, GFP_KERNEL); | |
299 | if (msg == NULL) | |
300 | return -ENOMEM; | |
301 | ||
302 | if (copy_from_user(msg, buffer, count)) { | |
303 | kfree(msg); | |
304 | return -EFAULT; | |
305 | } | |
306 | ||
307 | bt = filp->private_data; | |
308 | __trace_note_message(bt, "%s", msg); | |
309 | kfree(msg); | |
310 | ||
311 | return count; | |
312 | } | |
313 | ||
314 | static const struct file_operations blk_msg_fops = { | |
315 | .owner = THIS_MODULE, | |
316 | .open = blk_msg_open, | |
317 | .write = blk_msg_write, | |
318 | }; | |
319 | ||
2056a782 JA |
320 | /* |
321 | * Keep track of how many times we encountered a full subbuffer, to aid | |
322 | * the user space app in telling how many lost events there were. | |
323 | */ | |
324 | static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, | |
325 | void *prev_subbuf, size_t prev_padding) | |
326 | { | |
327 | struct blk_trace *bt; | |
328 | ||
329 | if (!relay_buf_full(buf)) | |
330 | return 1; | |
331 | ||
332 | bt = buf->chan->private_data; | |
333 | atomic_inc(&bt->dropped); | |
334 | return 0; | |
335 | } | |
336 | ||
337 | static int blk_remove_buf_file_callback(struct dentry *dentry) | |
338 | { | |
339 | debugfs_remove(dentry); | |
340 | return 0; | |
341 | } | |
342 | ||
343 | static struct dentry *blk_create_buf_file_callback(const char *filename, | |
344 | struct dentry *parent, | |
345 | int mode, | |
346 | struct rchan_buf *buf, | |
347 | int *is_global) | |
348 | { | |
349 | return debugfs_create_file(filename, mode, parent, buf, | |
350 | &relay_file_operations); | |
351 | } | |
352 | ||
353 | static struct rchan_callbacks blk_relay_callbacks = { | |
354 | .subbuf_start = blk_subbuf_start_callback, | |
355 | .create_buf_file = blk_create_buf_file_callback, | |
356 | .remove_buf_file = blk_remove_buf_file_callback, | |
357 | }; | |
358 | ||
359 | /* | |
360 | * Setup everything required to start tracing | |
361 | */ | |
6da127ad | 362 | int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
171044d4 | 363 | struct blk_user_trace_setup *buts) |
2056a782 | 364 | { |
2056a782 JA |
365 | struct blk_trace *old_bt, *bt = NULL; |
366 | struct dentry *dir = NULL; | |
2056a782 JA |
367 | int ret, i; |
368 | ||
171044d4 | 369 | if (!buts->buf_size || !buts->buf_nr) |
2056a782 JA |
370 | return -EINVAL; |
371 | ||
0497b345 JA |
372 | strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); |
373 | buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; | |
2056a782 JA |
374 | |
375 | /* | |
376 | * some device names have larger paths - convert the slashes | |
377 | * to underscores for this to work as expected | |
378 | */ | |
171044d4 AB |
379 | for (i = 0; i < strlen(buts->name); i++) |
380 | if (buts->name[i] == '/') | |
381 | buts->name[i] = '_'; | |
2056a782 JA |
382 | |
383 | ret = -ENOMEM; | |
384 | bt = kzalloc(sizeof(*bt), GFP_KERNEL); | |
385 | if (!bt) | |
386 | goto err; | |
387 | ||
388 | bt->sequence = alloc_percpu(unsigned long); | |
389 | if (!bt->sequence) | |
390 | goto err; | |
391 | ||
64565911 JA |
392 | bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG); |
393 | if (!bt->msg_data) | |
394 | goto err; | |
395 | ||
2056a782 | 396 | ret = -ENOENT; |
171044d4 | 397 | dir = blk_create_tree(buts->name); |
2056a782 JA |
398 | if (!dir) |
399 | goto err; | |
400 | ||
401 | bt->dir = dir; | |
6da127ad | 402 | bt->dev = dev; |
2056a782 JA |
403 | atomic_set(&bt->dropped, 0); |
404 | ||
405 | ret = -EIO; | |
406 | bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); | |
407 | if (!bt->dropped_file) | |
408 | goto err; | |
409 | ||
02c62304 AB |
410 | bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); |
411 | if (!bt->msg_file) | |
412 | goto err; | |
413 | ||
171044d4 AB |
414 | bt->rchan = relay_open("trace", dir, buts->buf_size, |
415 | buts->buf_nr, &blk_relay_callbacks, bt); | |
2056a782 JA |
416 | if (!bt->rchan) |
417 | goto err; | |
2056a782 | 418 | |
171044d4 | 419 | bt->act_mask = buts->act_mask; |
2056a782 JA |
420 | if (!bt->act_mask) |
421 | bt->act_mask = (u16) -1; | |
422 | ||
171044d4 AB |
423 | bt->start_lba = buts->start_lba; |
424 | bt->end_lba = buts->end_lba; | |
2056a782 JA |
425 | if (!bt->end_lba) |
426 | bt->end_lba = -1ULL; | |
427 | ||
171044d4 | 428 | bt->pid = buts->pid; |
2056a782 JA |
429 | bt->trace_state = Blktrace_setup; |
430 | ||
431 | ret = -EBUSY; | |
432 | old_bt = xchg(&q->blk_trace, bt); | |
433 | if (old_bt) { | |
434 | (void) xchg(&q->blk_trace, old_bt); | |
435 | goto err; | |
436 | } | |
437 | ||
438 | return 0; | |
439 | err: | |
440 | if (dir) | |
441 | blk_remove_tree(dir); | |
442 | if (bt) { | |
02c62304 AB |
443 | if (bt->msg_file) |
444 | debugfs_remove(bt->msg_file); | |
2056a782 JA |
445 | if (bt->dropped_file) |
446 | debugfs_remove(bt->dropped_file); | |
a1205868 | 447 | free_percpu(bt->sequence); |
64565911 | 448 | free_percpu(bt->msg_data); |
2056a782 JA |
449 | if (bt->rchan) |
450 | relay_close(bt->rchan); | |
451 | kfree(bt); | |
452 | } | |
453 | return ret; | |
454 | } | |
171044d4 | 455 | |
6da127ad CS |
456 | int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
457 | char __user *arg) | |
171044d4 AB |
458 | { |
459 | struct blk_user_trace_setup buts; | |
460 | int ret; | |
461 | ||
462 | ret = copy_from_user(&buts, arg, sizeof(buts)); | |
463 | if (ret) | |
464 | return -EFAULT; | |
465 | ||
6da127ad | 466 | ret = do_blk_trace_setup(q, name, dev, &buts); |
171044d4 AB |
467 | if (ret) |
468 | return ret; | |
469 | ||
470 | if (copy_to_user(arg, &buts, sizeof(buts))) | |
471 | return -EFAULT; | |
472 | ||
473 | return 0; | |
474 | } | |
6da127ad | 475 | EXPORT_SYMBOL_GPL(blk_trace_setup); |
2056a782 | 476 | |
6da127ad | 477 | int blk_trace_startstop(struct request_queue *q, int start) |
2056a782 JA |
478 | { |
479 | struct blk_trace *bt; | |
480 | int ret; | |
481 | ||
482 | if ((bt = q->blk_trace) == NULL) | |
483 | return -EINVAL; | |
484 | ||
485 | /* | |
486 | * For starting a trace, we can transition from a setup or stopped | |
487 | * trace. For stopping a trace, the state must be running | |
488 | */ | |
489 | ret = -EINVAL; | |
490 | if (start) { | |
491 | if (bt->trace_state == Blktrace_setup || | |
492 | bt->trace_state == Blktrace_stopped) { | |
493 | blktrace_seq++; | |
494 | smp_mb(); | |
495 | bt->trace_state = Blktrace_running; | |
be1c6341 OK |
496 | |
497 | trace_note_time(bt); | |
2056a782 JA |
498 | ret = 0; |
499 | } | |
500 | } else { | |
501 | if (bt->trace_state == Blktrace_running) { | |
502 | bt->trace_state = Blktrace_stopped; | |
503 | relay_flush(bt->rchan); | |
504 | ret = 0; | |
505 | } | |
506 | } | |
507 | ||
508 | return ret; | |
509 | } | |
6da127ad | 510 | EXPORT_SYMBOL_GPL(blk_trace_startstop); |
2056a782 JA |
511 | |
512 | /** | |
513 | * blk_trace_ioctl: - handle the ioctls associated with tracing | |
514 | * @bdev: the block device | |
515 | * @cmd: the ioctl cmd | |
516 | * @arg: the argument data, if any | |
517 | * | |
518 | **/ | |
519 | int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) | |
520 | { | |
165125e1 | 521 | struct request_queue *q; |
2056a782 | 522 | int ret, start = 0; |
6da127ad | 523 | char b[BDEVNAME_SIZE]; |
2056a782 JA |
524 | |
525 | q = bdev_get_queue(bdev); | |
526 | if (!q) | |
527 | return -ENXIO; | |
528 | ||
529 | mutex_lock(&bdev->bd_mutex); | |
530 | ||
531 | switch (cmd) { | |
532 | case BLKTRACESETUP: | |
f36f21ec | 533 | bdevname(bdev, b); |
6da127ad | 534 | ret = blk_trace_setup(q, b, bdev->bd_dev, arg); |
2056a782 JA |
535 | break; |
536 | case BLKTRACESTART: | |
537 | start = 1; | |
538 | case BLKTRACESTOP: | |
539 | ret = blk_trace_startstop(q, start); | |
540 | break; | |
541 | case BLKTRACETEARDOWN: | |
542 | ret = blk_trace_remove(q); | |
543 | break; | |
544 | default: | |
545 | ret = -ENOTTY; | |
546 | break; | |
547 | } | |
548 | ||
549 | mutex_unlock(&bdev->bd_mutex); | |
550 | return ret; | |
551 | } | |
552 | ||
553 | /** | |
554 | * blk_trace_shutdown: - stop and cleanup trace structures | |
555 | * @q: the request queue associated with the device | |
556 | * | |
557 | **/ | |
165125e1 | 558 | void blk_trace_shutdown(struct request_queue *q) |
2056a782 | 559 | { |
6c5c9341 AD |
560 | if (q->blk_trace) { |
561 | blk_trace_startstop(q, 0); | |
562 | blk_trace_remove(q); | |
563 | } | |
2056a782 | 564 | } |