blob: 028120a0965aa9a723196d1f245012151459ae3a [file] [log] [blame]
Jens Axboe2056a782006-03-23 20:00:26 +01001/*
Jens Axboe0fe23472006-09-04 15:41:16 +02002 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
Jens Axboe2056a782006-03-23 20:00:26 +01003 *
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 */
Jens Axboe2056a782006-03-23 20:00:26 +010018#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>
Olaf Kirchbe1c6342006-12-01 10:39:12 +010025#include <linux/time.h>
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +010026#include <trace/block.h>
Jens Axboe2056a782006-03-23 20:00:26 +010027#include <asm/uaccess.h>
28
Jens Axboe2056a782006-03-23 20:00:26 +010029static unsigned int blktrace_seq __read_mostly = 1;
30
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +010031/* Global reference count of probes */
32static DEFINE_MUTEX(blk_probe_mutex);
33static atomic_t blk_probes_ref = ATOMIC_INIT(0);
34
35static int blk_register_tracepoints(void);
36static void blk_unregister_tracepoints(void);
37
Jens Axboe2056a782006-03-23 20:00:26 +010038/*
Olaf Kirchbe1c6342006-12-01 10:39:12 +010039 * Send out a notify message.
40 */
Jens Axboea8630552006-12-04 09:30:58 +010041static void trace_note(struct blk_trace *bt, pid_t pid, int action,
42 const void *data, size_t len)
Olaf Kirchbe1c6342006-12-01 10:39:12 +010043{
44 struct blk_io_trace *t;
Olaf Kirchbe1c6342006-12-01 10:39:12 +010045
46 t = relay_reserve(bt->rchan, sizeof(*t) + len);
Jens Axboed3d9d2a2006-12-04 09:27:41 +010047 if (t) {
48 const int cpu = smp_processor_id();
Olaf Kirchbe1c6342006-12-01 10:39:12 +010049
Jens Axboed3d9d2a2006-12-04 09:27:41 +010050 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
Ingo Molnar2997c8c2008-01-11 13:35:54 +010051 t->time = ktime_to_ns(ktime_get());
Jens Axboed3d9d2a2006-12-04 09:27:41 +010052 t->device = bt->dev;
53 t->action = action;
54 t->pid = pid;
55 t->cpu = cpu;
56 t->pdu_len = len;
57 memcpy((void *) t + sizeof(*t), data, len);
58 }
Olaf Kirchbe1c6342006-12-01 10:39:12 +010059}
60
61/*
Jens Axboe2056a782006-03-23 20:00:26 +010062 * Send out a notify for this process, if we haven't done so since a trace
63 * started
64 */
65static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
66{
Jens Axboea8630552006-12-04 09:30:58 +010067 tsk->btrace_seq = blktrace_seq;
68 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
Olaf Kirchbe1c6342006-12-01 10:39:12 +010069}
Jens Axboe2056a782006-03-23 20:00:26 +010070
Olaf Kirchbe1c6342006-12-01 10:39:12 +010071static void trace_note_time(struct blk_trace *bt)
72{
73 struct timespec now;
74 unsigned long flags;
75 u32 words[2];
76
77 getnstimeofday(&now);
78 words[0] = now.tv_sec;
79 words[1] = now.tv_nsec;
80
81 local_irq_save(flags);
82 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
83 local_irq_restore(flags);
Jens Axboe2056a782006-03-23 20:00:26 +010084}
85
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020086void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
87{
88 int n;
89 va_list args;
Carl Henrik Lunde14a73f52008-06-12 20:13:58 +020090 unsigned long flags;
Jens Axboe64565912008-05-28 14:45:33 +020091 char *buf;
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020092
Carl Henrik Lunde14a73f52008-06-12 20:13:58 +020093 local_irq_save(flags);
Jens Axboe64565912008-05-28 14:45:33 +020094 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020095 va_start(args, fmt);
Jens Axboe64565912008-05-28 14:45:33 +020096 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020097 va_end(args);
98
Jens Axboe64565912008-05-28 14:45:33 +020099 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
Carl Henrik Lunde14a73f52008-06-12 20:13:58 +0200100 local_irq_restore(flags);
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +0200101}
102EXPORT_SYMBOL_GPL(__trace_note_message);
103
Jens Axboe2056a782006-03-23 20:00:26 +0100104static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
105 pid_t pid)
106{
107 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
108 return 1;
109 if (sector < bt->start_lba || sector > bt->end_lba)
110 return 1;
111 if (bt->pid && pid != bt->pid)
112 return 1;
113
114 return 0;
115}
116
117/*
118 * Data direction bit lookup
119 */
120static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
121
David Woodhouse35ba8f72008-08-10 12:33:00 +0100122/* The ilog2() calls fall out because they're constant */
123#define MASK_TC_BIT(rw, __name) ( (rw & (1 << BIO_RW_ ## __name)) << \
124 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name) )
Jens Axboe2056a782006-03-23 20:00:26 +0100125
126/*
127 * The worker for the various blk_add_trace*() types. Fills out a
128 * blk_io_trace structure and places it in a per-cpu subbuffer.
129 */
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100130static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
Jens Axboe2056a782006-03-23 20:00:26 +0100131 int rw, u32 what, int error, int pdu_len, void *pdu_data)
132{
133 struct task_struct *tsk = current;
134 struct blk_io_trace *t;
135 unsigned long flags;
136 unsigned long *sequence;
137 pid_t pid;
138 int cpu;
139
140 if (unlikely(bt->trace_state != Blktrace_running))
141 return;
142
143 what |= ddir_act[rw & WRITE];
David Woodhouse35ba8f72008-08-10 12:33:00 +0100144 what |= MASK_TC_BIT(rw, BARRIER);
Jens Axboe93dbb392009-02-16 10:25:40 +0100145 what |= MASK_TC_BIT(rw, SYNCIO);
David Woodhouse35ba8f72008-08-10 12:33:00 +0100146 what |= MASK_TC_BIT(rw, AHEAD);
147 what |= MASK_TC_BIT(rw, META);
148 what |= MASK_TC_BIT(rw, DISCARD);
Jens Axboe2056a782006-03-23 20:00:26 +0100149
150 pid = tsk->pid;
151 if (unlikely(act_log_check(bt, what, sector, pid)))
152 return;
153
154 /*
155 * A word about the locking here - we disable interrupts to reserve
156 * some space in the relay per-cpu buffer, to prevent an irq
Carl Henrik Lunde14a73f52008-06-12 20:13:58 +0200157 * from coming in and stepping on our toes.
Jens Axboe2056a782006-03-23 20:00:26 +0100158 */
159 local_irq_save(flags);
160
161 if (unlikely(tsk->btrace_seq != blktrace_seq))
162 trace_note_tsk(bt, tsk);
163
164 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
165 if (t) {
166 cpu = smp_processor_id();
167 sequence = per_cpu_ptr(bt->sequence, cpu);
168
169 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
170 t->sequence = ++(*sequence);
Ingo Molnar2997c8c2008-01-11 13:35:54 +0100171 t->time = ktime_to_ns(ktime_get());
Jens Axboe2056a782006-03-23 20:00:26 +0100172 t->sector = sector;
173 t->bytes = bytes;
174 t->action = what;
175 t->pid = pid;
176 t->device = bt->dev;
177 t->cpu = cpu;
178 t->error = error;
179 t->pdu_len = pdu_len;
180
181 if (pdu_len)
182 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
183 }
184
185 local_irq_restore(flags);
186}
187
Jens Axboe2056a782006-03-23 20:00:26 +0100188static struct dentry *blk_tree_root;
Jens Axboe11a57152008-01-11 13:37:01 +0100189static DEFINE_MUTEX(blk_tree_mutex);
Jens Axboe2056a782006-03-23 20:00:26 +0100190
191static void blk_trace_cleanup(struct blk_trace *bt)
192{
Alan D. Brunelle02c62302008-06-11 09:12:52 +0200193 debugfs_remove(bt->msg_file);
Jens Axboe2056a782006-03-23 20:00:26 +0100194 debugfs_remove(bt->dropped_file);
Jens Axboef48fc4d2009-01-05 10:17:25 +0100195 relay_close(bt->rchan);
Jens Axboe2056a782006-03-23 20:00:26 +0100196 free_percpu(bt->sequence);
Jens Axboe64565912008-05-28 14:45:33 +0200197 free_percpu(bt->msg_data);
Jens Axboe2056a782006-03-23 20:00:26 +0100198 kfree(bt);
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100199 mutex_lock(&blk_probe_mutex);
200 if (atomic_dec_and_test(&blk_probes_ref))
201 blk_unregister_tracepoints();
202 mutex_unlock(&blk_probe_mutex);
Jens Axboe2056a782006-03-23 20:00:26 +0100203}
204
Christof Schmitt6da127a2008-01-11 10:09:43 +0100205int blk_trace_remove(struct request_queue *q)
Jens Axboe2056a782006-03-23 20:00:26 +0100206{
207 struct blk_trace *bt;
208
209 bt = xchg(&q->blk_trace, NULL);
210 if (!bt)
211 return -EINVAL;
212
213 if (bt->trace_state == Blktrace_setup ||
214 bt->trace_state == Blktrace_stopped)
215 blk_trace_cleanup(bt);
216
217 return 0;
218}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100219EXPORT_SYMBOL_GPL(blk_trace_remove);
Jens Axboe2056a782006-03-23 20:00:26 +0100220
221static int blk_dropped_open(struct inode *inode, struct file *filp)
222{
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700223 filp->private_data = inode->i_private;
Jens Axboe2056a782006-03-23 20:00:26 +0100224
225 return 0;
226}
227
228static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
229 size_t count, loff_t *ppos)
230{
231 struct blk_trace *bt = filp->private_data;
232 char buf[16];
233
234 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
235
236 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
237}
238
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800239static const struct file_operations blk_dropped_fops = {
Jens Axboe2056a782006-03-23 20:00:26 +0100240 .owner = THIS_MODULE,
241 .open = blk_dropped_open,
242 .read = blk_dropped_read,
243};
244
Alan D. Brunelle02c62302008-06-11 09:12:52 +0200245static int blk_msg_open(struct inode *inode, struct file *filp)
246{
247 filp->private_data = inode->i_private;
248
249 return 0;
250}
251
252static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
253 size_t count, loff_t *ppos)
254{
255 char *msg;
256 struct blk_trace *bt;
257
258 if (count > BLK_TN_MAX_MSG)
259 return -EINVAL;
260
261 msg = kmalloc(count, GFP_KERNEL);
262 if (msg == NULL)
263 return -ENOMEM;
264
265 if (copy_from_user(msg, buffer, count)) {
266 kfree(msg);
267 return -EFAULT;
268 }
269
270 bt = filp->private_data;
271 __trace_note_message(bt, "%s", msg);
272 kfree(msg);
273
274 return count;
275}
276
277static const struct file_operations blk_msg_fops = {
278 .owner = THIS_MODULE,
279 .open = blk_msg_open,
280 .write = blk_msg_write,
281};
282
Jens Axboe2056a782006-03-23 20:00:26 +0100283/*
284 * Keep track of how many times we encountered a full subbuffer, to aid
285 * the user space app in telling how many lost events there were.
286 */
287static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
288 void *prev_subbuf, size_t prev_padding)
289{
290 struct blk_trace *bt;
291
292 if (!relay_buf_full(buf))
293 return 1;
294
295 bt = buf->chan->private_data;
296 atomic_inc(&bt->dropped);
297 return 0;
298}
299
300static int blk_remove_buf_file_callback(struct dentry *dentry)
301{
Jens Axboef48fc4d2009-01-05 10:17:25 +0100302 struct dentry *parent = dentry->d_parent;
Jens Axboe2056a782006-03-23 20:00:26 +0100303 debugfs_remove(dentry);
Jens Axboef48fc4d2009-01-05 10:17:25 +0100304
305 /*
306 * this will fail for all but the last file, but that is ok. what we
307 * care about is the top level buts->name directory going away, when
308 * the last trace file is gone. Then we don't have to rmdir() that
309 * manually on trace stop, so it nicely solves the issue with
310 * force killing of running traces.
311 */
312
313 debugfs_remove(parent);
Jens Axboe2056a782006-03-23 20:00:26 +0100314 return 0;
315}
316
317static struct dentry *blk_create_buf_file_callback(const char *filename,
318 struct dentry *parent,
319 int mode,
320 struct rchan_buf *buf,
321 int *is_global)
322{
323 return debugfs_create_file(filename, mode, parent, buf,
324 &relay_file_operations);
325}
326
327static struct rchan_callbacks blk_relay_callbacks = {
328 .subbuf_start = blk_subbuf_start_callback,
329 .create_buf_file = blk_create_buf_file_callback,
330 .remove_buf_file = blk_remove_buf_file_callback,
331};
332
333/*
334 * Setup everything required to start tracing
335 */
Christof Schmitt6da127a2008-01-11 10:09:43 +0100336int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
Arnd Bergmann171044d42007-10-09 13:23:53 +0200337 struct blk_user_trace_setup *buts)
Jens Axboe2056a782006-03-23 20:00:26 +0100338{
Jens Axboe2056a782006-03-23 20:00:26 +0100339 struct blk_trace *old_bt, *bt = NULL;
340 struct dentry *dir = NULL;
Jens Axboe2056a782006-03-23 20:00:26 +0100341 int ret, i;
342
Arnd Bergmann171044d42007-10-09 13:23:53 +0200343 if (!buts->buf_size || !buts->buf_nr)
Jens Axboe2056a782006-03-23 20:00:26 +0100344 return -EINVAL;
345
Jens Axboe0497b342008-10-01 16:16:25 +0200346 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
347 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
Jens Axboe2056a782006-03-23 20:00:26 +0100348
349 /*
350 * some device names have larger paths - convert the slashes
351 * to underscores for this to work as expected
352 */
Arnd Bergmann171044d42007-10-09 13:23:53 +0200353 for (i = 0; i < strlen(buts->name); i++)
354 if (buts->name[i] == '/')
355 buts->name[i] = '_';
Jens Axboe2056a782006-03-23 20:00:26 +0100356
357 ret = -ENOMEM;
358 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
359 if (!bt)
360 goto err;
361
362 bt->sequence = alloc_percpu(unsigned long);
363 if (!bt->sequence)
364 goto err;
365
Rusty Russell313e4582009-02-20 16:29:08 +0900366 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
Jens Axboe64565912008-05-28 14:45:33 +0200367 if (!bt->msg_data)
368 goto err;
369
Jens Axboe2056a782006-03-23 20:00:26 +0100370 ret = -ENOENT;
Jens Axboef48fc4d2009-01-05 10:17:25 +0100371
372 if (!blk_tree_root) {
373 blk_tree_root = debugfs_create_dir("block", NULL);
374 if (!blk_tree_root)
375 return -ENOMEM;
376 }
377
378 dir = debugfs_create_dir(buts->name, blk_tree_root);
379
Jens Axboe2056a782006-03-23 20:00:26 +0100380 if (!dir)
381 goto err;
382
383 bt->dir = dir;
Christof Schmitt6da127a2008-01-11 10:09:43 +0100384 bt->dev = dev;
Jens Axboe2056a782006-03-23 20:00:26 +0100385 atomic_set(&bt->dropped, 0);
386
387 ret = -EIO;
388 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
389 if (!bt->dropped_file)
390 goto err;
391
Alan D. Brunelle02c62302008-06-11 09:12:52 +0200392 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
393 if (!bt->msg_file)
394 goto err;
395
Arnd Bergmann171044d42007-10-09 13:23:53 +0200396 bt->rchan = relay_open("trace", dir, buts->buf_size,
397 buts->buf_nr, &blk_relay_callbacks, bt);
Jens Axboe2056a782006-03-23 20:00:26 +0100398 if (!bt->rchan)
399 goto err;
Jens Axboe2056a782006-03-23 20:00:26 +0100400
Arnd Bergmann171044d42007-10-09 13:23:53 +0200401 bt->act_mask = buts->act_mask;
Jens Axboe2056a782006-03-23 20:00:26 +0100402 if (!bt->act_mask)
403 bt->act_mask = (u16) -1;
404
Arnd Bergmann171044d42007-10-09 13:23:53 +0200405 bt->start_lba = buts->start_lba;
406 bt->end_lba = buts->end_lba;
Jens Axboe2056a782006-03-23 20:00:26 +0100407 if (!bt->end_lba)
408 bt->end_lba = -1ULL;
409
Arnd Bergmann171044d42007-10-09 13:23:53 +0200410 bt->pid = buts->pid;
Jens Axboe2056a782006-03-23 20:00:26 +0100411 bt->trace_state = Blktrace_setup;
412
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100413 mutex_lock(&blk_probe_mutex);
414 if (atomic_add_return(1, &blk_probes_ref) == 1) {
415 ret = blk_register_tracepoints();
416 if (ret)
417 goto probe_err;
418 }
419 mutex_unlock(&blk_probe_mutex);
420
Jens Axboe2056a782006-03-23 20:00:26 +0100421 ret = -EBUSY;
422 old_bt = xchg(&q->blk_trace, bt);
423 if (old_bt) {
424 (void) xchg(&q->blk_trace, old_bt);
425 goto err;
426 }
427
428 return 0;
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100429probe_err:
430 atomic_dec(&blk_probes_ref);
431 mutex_unlock(&blk_probe_mutex);
Jens Axboe2056a782006-03-23 20:00:26 +0100432err:
Jens Axboe2056a782006-03-23 20:00:26 +0100433 if (bt) {
Alan D. Brunelle02c62302008-06-11 09:12:52 +0200434 if (bt->msg_file)
435 debugfs_remove(bt->msg_file);
Jens Axboe2056a782006-03-23 20:00:26 +0100436 if (bt->dropped_file)
437 debugfs_remove(bt->dropped_file);
Alan Sterna1205862006-12-06 20:32:37 -0800438 free_percpu(bt->sequence);
Jens Axboe64565912008-05-28 14:45:33 +0200439 free_percpu(bt->msg_data);
Jens Axboe2056a782006-03-23 20:00:26 +0100440 if (bt->rchan)
441 relay_close(bt->rchan);
442 kfree(bt);
443 }
444 return ret;
445}
446
Christof Schmitt6da127a2008-01-11 10:09:43 +0100447int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
448 char __user *arg)
Arnd Bergmann171044d42007-10-09 13:23:53 +0200449{
450 struct blk_user_trace_setup buts;
451 int ret;
452
453 ret = copy_from_user(&buts, arg, sizeof(buts));
454 if (ret)
455 return -EFAULT;
456
Christof Schmitt6da127a2008-01-11 10:09:43 +0100457 ret = do_blk_trace_setup(q, name, dev, &buts);
Arnd Bergmann171044d42007-10-09 13:23:53 +0200458 if (ret)
459 return ret;
460
461 if (copy_to_user(arg, &buts, sizeof(buts)))
462 return -EFAULT;
463
464 return 0;
465}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100466EXPORT_SYMBOL_GPL(blk_trace_setup);
Arnd Bergmann171044d42007-10-09 13:23:53 +0200467
Christof Schmitt6da127a2008-01-11 10:09:43 +0100468int blk_trace_startstop(struct request_queue *q, int start)
Jens Axboe2056a782006-03-23 20:00:26 +0100469{
470 struct blk_trace *bt;
471 int ret;
472
473 if ((bt = q->blk_trace) == NULL)
474 return -EINVAL;
475
476 /*
477 * For starting a trace, we can transition from a setup or stopped
478 * trace. For stopping a trace, the state must be running
479 */
480 ret = -EINVAL;
481 if (start) {
482 if (bt->trace_state == Blktrace_setup ||
483 bt->trace_state == Blktrace_stopped) {
484 blktrace_seq++;
485 smp_mb();
486 bt->trace_state = Blktrace_running;
Olaf Kirchbe1c6342006-12-01 10:39:12 +0100487
488 trace_note_time(bt);
Jens Axboe2056a782006-03-23 20:00:26 +0100489 ret = 0;
490 }
491 } else {
492 if (bt->trace_state == Blktrace_running) {
493 bt->trace_state = Blktrace_stopped;
494 relay_flush(bt->rchan);
495 ret = 0;
496 }
497 }
498
499 return ret;
500}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100501EXPORT_SYMBOL_GPL(blk_trace_startstop);
Jens Axboe2056a782006-03-23 20:00:26 +0100502
503/**
504 * blk_trace_ioctl: - handle the ioctls associated with tracing
505 * @bdev: the block device
506 * @cmd: the ioctl cmd
507 * @arg: the argument data, if any
508 *
509 **/
510int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
511{
Jens Axboe165125e2007-07-24 09:28:11 +0200512 struct request_queue *q;
Jens Axboe2056a782006-03-23 20:00:26 +0100513 int ret, start = 0;
Christof Schmitt6da127a2008-01-11 10:09:43 +0100514 char b[BDEVNAME_SIZE];
Jens Axboe2056a782006-03-23 20:00:26 +0100515
516 q = bdev_get_queue(bdev);
517 if (!q)
518 return -ENXIO;
519
520 mutex_lock(&bdev->bd_mutex);
521
522 switch (cmd) {
523 case BLKTRACESETUP:
Jean Delvaref36f21e2008-05-12 14:02:33 -0700524 bdevname(bdev, b);
Christof Schmitt6da127a2008-01-11 10:09:43 +0100525 ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
Jens Axboe2056a782006-03-23 20:00:26 +0100526 break;
527 case BLKTRACESTART:
528 start = 1;
529 case BLKTRACESTOP:
530 ret = blk_trace_startstop(q, start);
531 break;
532 case BLKTRACETEARDOWN:
533 ret = blk_trace_remove(q);
534 break;
535 default:
536 ret = -ENOTTY;
537 break;
538 }
539
540 mutex_unlock(&bdev->bd_mutex);
541 return ret;
542}
543
544/**
545 * blk_trace_shutdown: - stop and cleanup trace structures
546 * @q: the request queue associated with the device
547 *
548 **/
Jens Axboe165125e2007-07-24 09:28:11 +0200549void blk_trace_shutdown(struct request_queue *q)
Jens Axboe2056a782006-03-23 20:00:26 +0100550{
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700551 if (q->blk_trace) {
552 blk_trace_startstop(q, 0);
553 blk_trace_remove(q);
554 }
Jens Axboe2056a782006-03-23 20:00:26 +0100555}
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100556
557/*
558 * blktrace probes
559 */
560
561/**
562 * blk_add_trace_rq - Add a trace for a request oriented action
563 * @q: queue the io is for
564 * @rq: the source request
565 * @what: the action
566 *
567 * Description:
568 * Records an action against a request. Will log the bio offset + size.
569 *
570 **/
571static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
572 u32 what)
573{
574 struct blk_trace *bt = q->blk_trace;
575 int rw = rq->cmd_flags & 0x03;
576
577 if (likely(!bt))
578 return;
579
580 if (blk_discard_rq(rq))
581 rw |= (1 << BIO_RW_DISCARD);
582
583 if (blk_pc_request(rq)) {
584 what |= BLK_TC_ACT(BLK_TC_PC);
585 __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
586 sizeof(rq->cmd), rq->cmd);
587 } else {
588 what |= BLK_TC_ACT(BLK_TC_FS);
589 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
590 rw, what, rq->errors, 0, NULL);
591 }
592}
593
594static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
595{
596 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
597}
598
599static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
600{
601 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
602}
603
604static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
605{
606 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
607}
608
609static void blk_add_trace_rq_requeue(struct request_queue *q, struct request *rq)
610{
611 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
612}
613
614static void blk_add_trace_rq_complete(struct request_queue *q, struct request *rq)
615{
616 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
617}
618
619/**
620 * blk_add_trace_bio - Add a trace for a bio oriented action
621 * @q: queue the io is for
622 * @bio: the source bio
623 * @what: the action
624 *
625 * Description:
626 * Records an action against a bio. Will log the bio offset + size.
627 *
628 **/
629static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
630 u32 what)
631{
632 struct blk_trace *bt = q->blk_trace;
633
634 if (likely(!bt))
635 return;
636
637 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
638 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
639}
640
641static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
642{
643 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
644}
645
646static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
647{
648 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
649}
650
651static void blk_add_trace_bio_backmerge(struct request_queue *q, struct bio *bio)
652{
653 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
654}
655
656static void blk_add_trace_bio_frontmerge(struct request_queue *q, struct bio *bio)
657{
658 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
659}
660
661static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
662{
663 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
664}
665
666static void blk_add_trace_getrq(struct request_queue *q, struct bio *bio, int rw)
667{
668 if (bio)
669 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
670 else {
671 struct blk_trace *bt = q->blk_trace;
672
673 if (bt)
674 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
675 }
676}
677
678
679static void blk_add_trace_sleeprq(struct request_queue *q, struct bio *bio, int rw)
680{
681 if (bio)
682 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
683 else {
684 struct blk_trace *bt = q->blk_trace;
685
686 if (bt)
687 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 0, 0, NULL);
688 }
689}
690
691static void blk_add_trace_plug(struct request_queue *q)
692{
693 struct blk_trace *bt = q->blk_trace;
694
695 if (bt)
696 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
697}
698
699static void blk_add_trace_unplug_io(struct request_queue *q)
700{
701 struct blk_trace *bt = q->blk_trace;
702
703 if (bt) {
704 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
705 __be64 rpdu = cpu_to_be64(pdu);
706
707 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
708 sizeof(rpdu), &rpdu);
709 }
710}
711
712static void blk_add_trace_unplug_timer(struct request_queue *q)
713{
714 struct blk_trace *bt = q->blk_trace;
715
716 if (bt) {
717 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
718 __be64 rpdu = cpu_to_be64(pdu);
719
720 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
721 sizeof(rpdu), &rpdu);
722 }
723}
724
725static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
726 unsigned int pdu)
727{
728 struct blk_trace *bt = q->blk_trace;
729
730 if (bt) {
731 __be64 rpdu = cpu_to_be64(pdu);
732
733 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
734 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
735 sizeof(rpdu), &rpdu);
736 }
737}
738
739/**
740 * blk_add_trace_remap - Add a trace for a remap operation
741 * @q: queue the io is for
742 * @bio: the source bio
743 * @dev: target device
744 * @from: source sector
745 * @to: target sector
746 *
747 * Description:
748 * Device mapper or raid target sometimes need to split a bio because
749 * it spans a stripe (or similar). Add a trace for that action.
750 *
751 **/
752static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
753 dev_t dev, sector_t from, sector_t to)
754{
755 struct blk_trace *bt = q->blk_trace;
756 struct blk_io_trace_remap r;
757
758 if (likely(!bt))
759 return;
760
761 r.device = cpu_to_be32(dev);
762 r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
763 r.sector = cpu_to_be64(to);
764
765 __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
766 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
767}
768
769/**
770 * blk_add_driver_data - Add binary message with driver-specific data
771 * @q: queue the io is for
772 * @rq: io request
773 * @data: driver-specific data
774 * @len: length of driver-specific data
775 *
776 * Description:
777 * Some drivers might want to write driver-specific data per request.
778 *
779 **/
780void blk_add_driver_data(struct request_queue *q,
781 struct request *rq,
782 void *data, size_t len)
783{
784 struct blk_trace *bt = q->blk_trace;
785
786 if (likely(!bt))
787 return;
788
789 if (blk_pc_request(rq))
790 __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
791 rq->errors, len, data);
792 else
793 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
794 0, BLK_TA_DRV_DATA, rq->errors, len, data);
795}
796EXPORT_SYMBOL_GPL(blk_add_driver_data);
797
798static int blk_register_tracepoints(void)
799{
800 int ret;
801
802 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
803 WARN_ON(ret);
804 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
805 WARN_ON(ret);
806 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
807 WARN_ON(ret);
808 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
809 WARN_ON(ret);
810 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
811 WARN_ON(ret);
812 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
813 WARN_ON(ret);
814 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
815 WARN_ON(ret);
816 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
817 WARN_ON(ret);
818 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
819 WARN_ON(ret);
820 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
821 WARN_ON(ret);
822 ret = register_trace_block_getrq(blk_add_trace_getrq);
823 WARN_ON(ret);
824 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
825 WARN_ON(ret);
826 ret = register_trace_block_plug(blk_add_trace_plug);
827 WARN_ON(ret);
828 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
829 WARN_ON(ret);
830 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
831 WARN_ON(ret);
832 ret = register_trace_block_split(blk_add_trace_split);
833 WARN_ON(ret);
834 ret = register_trace_block_remap(blk_add_trace_remap);
835 WARN_ON(ret);
836 return 0;
837}
838
839static void blk_unregister_tracepoints(void)
840{
841 unregister_trace_block_remap(blk_add_trace_remap);
842 unregister_trace_block_split(blk_add_trace_split);
843 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
844 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
845 unregister_trace_block_plug(blk_add_trace_plug);
846 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
847 unregister_trace_block_getrq(blk_add_trace_getrq);
848 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
849 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
850 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
851 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
852 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
853 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
854 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
855 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
856 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
857 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
858
859 tracepoint_synchronize_unregister();
860}