2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
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.
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.
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
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/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/time.h>
27 #include <linux/uaccess.h>
29 #include <trace/events/block.h>
31 #include "trace_output.h"
33 #ifdef CONFIG_BLK_DEV_IO_TRACE
35 static unsigned int blktrace_seq __read_mostly = 1;
37 static struct trace_array *blk_tr;
38 static bool blk_tracer_enabled __read_mostly;
40 /* Select an alternative, minimalistic output than the original one */
41 #define TRACE_BLK_OPT_CLASSIC 0x1
43 static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
49 static struct tracer_flags blk_tracer_flags = {
51 .opts = blk_tracer_opts,
54 /* Global reference count of probes */
55 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57 static void blk_register_tracepoints(void);
58 static void blk_unregister_tracepoints(void);
61 * Send out a notify message.
63 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
64 const void *data, size_t len)
66 struct blk_io_trace *t;
67 struct ring_buffer_event *event = NULL;
68 struct ring_buffer *buffer = NULL;
70 int cpu = smp_processor_id();
71 bool blk_tracer = blk_tracer_enabled;
74 buffer = blk_tr->buffer;
76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
81 t = ring_buffer_event_data(event);
88 t = relay_reserve(bt->rchan, sizeof(*t) + len);
90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
91 t->time = ktime_to_ns(ktime_get());
98 memcpy((void *) t + sizeof(*t), data, len);
101 trace_buffer_unlock_commit(buffer, event, 0, pc);
106 * Send out a notify for this process, if we haven't done so since a trace
109 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
111 tsk->btrace_seq = blktrace_seq;
112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
115 static void trace_note_time(struct blk_trace *bt)
121 getnstimeofday(&now);
122 words[0] = now.tv_sec;
123 words[1] = now.tv_nsec;
125 local_irq_save(flags);
126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
127 local_irq_restore(flags);
130 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
137 if (unlikely(bt->trace_state != Blktrace_running &&
138 !blk_tracer_enabled))
141 local_irq_save(flags);
142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
148 local_irq_restore(flags);
150 EXPORT_SYMBOL_GPL(__trace_note_message);
152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
157 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
159 if (bt->pid && pid != bt->pid)
166 * Data direction bit lookup
168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
169 BLK_TC_ACT(BLK_TC_WRITE) };
171 #define BLK_TC_RAHEAD BLK_TC_AHEAD
173 /* The ilog2() calls fall out because they're constant */
174 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
175 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
178 * The worker for the various blk_add_trace*() types. Fills out a
179 * blk_io_trace structure and places it in a per-cpu subbuffer.
181 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
182 int rw, u32 what, int error, int pdu_len, void *pdu_data)
184 struct task_struct *tsk = current;
185 struct ring_buffer_event *event = NULL;
186 struct ring_buffer *buffer = NULL;
187 struct blk_io_trace *t;
188 unsigned long flags = 0;
189 unsigned long *sequence;
192 bool blk_tracer = blk_tracer_enabled;
194 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
197 what |= ddir_act[rw & WRITE];
198 what |= MASK_TC_BIT(rw, SYNC);
199 what |= MASK_TC_BIT(rw, RAHEAD);
200 what |= MASK_TC_BIT(rw, META);
201 what |= MASK_TC_BIT(rw, DISCARD);
204 if (act_log_check(bt, what, sector, pid))
206 cpu = raw_smp_processor_id();
209 tracing_record_cmdline(current);
211 buffer = blk_tr->buffer;
212 pc = preempt_count();
213 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
214 sizeof(*t) + pdu_len,
218 t = ring_buffer_event_data(event);
223 * A word about the locking here - we disable interrupts to reserve
224 * some space in the relay per-cpu buffer, to prevent an irq
225 * from coming in and stepping on our toes.
227 local_irq_save(flags);
229 if (unlikely(tsk->btrace_seq != blktrace_seq))
230 trace_note_tsk(bt, tsk);
232 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
234 sequence = per_cpu_ptr(bt->sequence, cpu);
236 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
237 t->sequence = ++(*sequence);
238 t->time = ktime_to_ns(ktime_get());
241 * These two are not needed in ftrace as they are in the
242 * generic trace_entry, filled by tracing_generic_entry_update,
243 * but for the trace_event->bin() synthesizer benefit we do it
254 t->pdu_len = pdu_len;
257 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
260 trace_buffer_unlock_commit(buffer, event, 0, pc);
265 local_irq_restore(flags);
268 static struct dentry *blk_tree_root;
269 static DEFINE_MUTEX(blk_tree_mutex);
271 static void blk_trace_free(struct blk_trace *bt)
273 debugfs_remove(bt->msg_file);
274 debugfs_remove(bt->dropped_file);
275 relay_close(bt->rchan);
276 debugfs_remove(bt->dir);
277 free_percpu(bt->sequence);
278 free_percpu(bt->msg_data);
282 static void blk_trace_cleanup(struct blk_trace *bt)
285 if (atomic_dec_and_test(&blk_probes_ref))
286 blk_unregister_tracepoints();
289 int blk_trace_remove(struct request_queue *q)
291 struct blk_trace *bt;
293 bt = xchg(&q->blk_trace, NULL);
297 if (bt->trace_state != Blktrace_running)
298 blk_trace_cleanup(bt);
302 EXPORT_SYMBOL_GPL(blk_trace_remove);
304 static int blk_dropped_open(struct inode *inode, struct file *filp)
306 filp->private_data = inode->i_private;
311 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
312 size_t count, loff_t *ppos)
314 struct blk_trace *bt = filp->private_data;
317 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
319 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
322 static const struct file_operations blk_dropped_fops = {
323 .owner = THIS_MODULE,
324 .open = blk_dropped_open,
325 .read = blk_dropped_read,
326 .llseek = default_llseek,
329 static int blk_msg_open(struct inode *inode, struct file *filp)
331 filp->private_data = inode->i_private;
336 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
337 size_t count, loff_t *ppos)
340 struct blk_trace *bt;
342 if (count >= BLK_TN_MAX_MSG)
345 msg = kmalloc(count + 1, GFP_KERNEL);
349 if (copy_from_user(msg, buffer, count)) {
355 bt = filp->private_data;
356 __trace_note_message(bt, "%s", msg);
362 static const struct file_operations blk_msg_fops = {
363 .owner = THIS_MODULE,
364 .open = blk_msg_open,
365 .write = blk_msg_write,
366 .llseek = noop_llseek,
370 * Keep track of how many times we encountered a full subbuffer, to aid
371 * the user space app in telling how many lost events there were.
373 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
374 void *prev_subbuf, size_t prev_padding)
376 struct blk_trace *bt;
378 if (!relay_buf_full(buf))
381 bt = buf->chan->private_data;
382 atomic_inc(&bt->dropped);
386 static int blk_remove_buf_file_callback(struct dentry *dentry)
388 debugfs_remove(dentry);
393 static struct dentry *blk_create_buf_file_callback(const char *filename,
394 struct dentry *parent,
396 struct rchan_buf *buf,
399 return debugfs_create_file(filename, mode, parent, buf,
400 &relay_file_operations);
403 static struct rchan_callbacks blk_relay_callbacks = {
404 .subbuf_start = blk_subbuf_start_callback,
405 .create_buf_file = blk_create_buf_file_callback,
406 .remove_buf_file = blk_remove_buf_file_callback,
409 static void blk_trace_setup_lba(struct blk_trace *bt,
410 struct block_device *bdev)
412 struct hd_struct *part = NULL;
415 part = bdev->bd_part;
418 bt->start_lba = part->start_sect;
419 bt->end_lba = part->start_sect + part->nr_sects;
427 * Setup everything required to start tracing
429 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
430 struct block_device *bdev,
431 struct blk_user_trace_setup *buts)
433 struct blk_trace *old_bt, *bt = NULL;
434 struct dentry *dir = NULL;
437 if (!buts->buf_size || !buts->buf_nr)
440 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
441 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
444 * some device names have larger paths - convert the slashes
445 * to underscores for this to work as expected
447 for (i = 0; i < strlen(buts->name); i++)
448 if (buts->name[i] == '/')
451 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
456 bt->sequence = alloc_percpu(unsigned long);
460 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
466 mutex_lock(&blk_tree_mutex);
467 if (!blk_tree_root) {
468 blk_tree_root = debugfs_create_dir("block", NULL);
469 if (!blk_tree_root) {
470 mutex_unlock(&blk_tree_mutex);
474 mutex_unlock(&blk_tree_mutex);
476 dir = debugfs_create_dir(buts->name, blk_tree_root);
483 atomic_set(&bt->dropped, 0);
486 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
488 if (!bt->dropped_file)
491 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
495 bt->rchan = relay_open("trace", dir, buts->buf_size,
496 buts->buf_nr, &blk_relay_callbacks, bt);
500 bt->act_mask = buts->act_mask;
502 bt->act_mask = (u16) -1;
504 blk_trace_setup_lba(bt, bdev);
506 /* overwrite with user settings */
508 bt->start_lba = buts->start_lba;
510 bt->end_lba = buts->end_lba;
513 bt->trace_state = Blktrace_setup;
516 old_bt = xchg(&q->blk_trace, bt);
518 (void) xchg(&q->blk_trace, old_bt);
522 if (atomic_inc_return(&blk_probes_ref) == 1)
523 blk_register_tracepoints();
531 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
532 struct block_device *bdev,
535 struct blk_user_trace_setup buts;
538 ret = copy_from_user(&buts, arg, sizeof(buts));
542 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
546 if (copy_to_user(arg, &buts, sizeof(buts))) {
552 EXPORT_SYMBOL_GPL(blk_trace_setup);
554 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
555 static int compat_blk_trace_setup(struct request_queue *q, char *name,
556 dev_t dev, struct block_device *bdev,
559 struct blk_user_trace_setup buts;
560 struct compat_blk_user_trace_setup cbuts;
563 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
566 buts = (struct blk_user_trace_setup) {
567 .act_mask = cbuts.act_mask,
568 .buf_size = cbuts.buf_size,
569 .buf_nr = cbuts.buf_nr,
570 .start_lba = cbuts.start_lba,
571 .end_lba = cbuts.end_lba,
574 memcpy(&buts.name, &cbuts.name, 32);
576 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
580 if (copy_to_user(arg, &buts.name, 32)) {
589 int blk_trace_startstop(struct request_queue *q, int start)
592 struct blk_trace *bt = q->blk_trace;
598 * For starting a trace, we can transition from a setup or stopped
599 * trace. For stopping a trace, the state must be running
603 if (bt->trace_state == Blktrace_setup ||
604 bt->trace_state == Blktrace_stopped) {
607 bt->trace_state = Blktrace_running;
613 if (bt->trace_state == Blktrace_running) {
614 bt->trace_state = Blktrace_stopped;
615 relay_flush(bt->rchan);
622 EXPORT_SYMBOL_GPL(blk_trace_startstop);
625 * blk_trace_ioctl: - handle the ioctls associated with tracing
626 * @bdev: the block device
627 * @cmd: the ioctl cmd
628 * @arg: the argument data, if any
631 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
633 struct request_queue *q;
635 char b[BDEVNAME_SIZE];
637 q = bdev_get_queue(bdev);
641 mutex_lock(&bdev->bd_mutex);
646 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
648 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
649 case BLKTRACESETUP32:
651 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
657 ret = blk_trace_startstop(q, start);
659 case BLKTRACETEARDOWN:
660 ret = blk_trace_remove(q);
667 mutex_unlock(&bdev->bd_mutex);
672 * blk_trace_shutdown: - stop and cleanup trace structures
673 * @q: the request queue associated with the device
676 void blk_trace_shutdown(struct request_queue *q)
679 blk_trace_startstop(q, 0);
689 * blk_add_trace_rq - Add a trace for a request oriented action
690 * @q: queue the io is for
691 * @rq: the source request
695 * Records an action against a request. Will log the bio offset + size.
698 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
701 struct blk_trace *bt = q->blk_trace;
702 int rw = rq->cmd_flags & 0x03;
707 if (rq->cmd_flags & REQ_DISCARD)
710 if (rq->cmd_flags & REQ_SECURE)
713 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
714 what |= BLK_TC_ACT(BLK_TC_PC);
715 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
716 what, rq->errors, rq->cmd_len, rq->cmd);
718 what |= BLK_TC_ACT(BLK_TC_FS);
719 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
720 what, rq->errors, 0, NULL);
724 static void blk_add_trace_rq_abort(void *ignore,
725 struct request_queue *q, struct request *rq)
727 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
730 static void blk_add_trace_rq_insert(void *ignore,
731 struct request_queue *q, struct request *rq)
733 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
736 static void blk_add_trace_rq_issue(void *ignore,
737 struct request_queue *q, struct request *rq)
739 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
742 static void blk_add_trace_rq_requeue(void *ignore,
743 struct request_queue *q,
746 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
749 static void blk_add_trace_rq_complete(void *ignore,
750 struct request_queue *q,
753 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
757 * blk_add_trace_bio - Add a trace for a bio oriented action
758 * @q: queue the io is for
759 * @bio: the source bio
763 * Records an action against a bio. Will log the bio offset + size.
766 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
769 struct blk_trace *bt = q->blk_trace;
774 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
775 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
778 static void blk_add_trace_bio_bounce(void *ignore,
779 struct request_queue *q, struct bio *bio)
781 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
784 static void blk_add_trace_bio_complete(void *ignore,
785 struct request_queue *q, struct bio *bio,
788 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
791 static void blk_add_trace_bio_backmerge(void *ignore,
792 struct request_queue *q,
795 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
798 static void blk_add_trace_bio_frontmerge(void *ignore,
799 struct request_queue *q,
802 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
805 static void blk_add_trace_bio_queue(void *ignore,
806 struct request_queue *q, struct bio *bio)
808 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
811 static void blk_add_trace_getrq(void *ignore,
812 struct request_queue *q,
813 struct bio *bio, int rw)
816 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
818 struct blk_trace *bt = q->blk_trace;
821 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
826 static void blk_add_trace_sleeprq(void *ignore,
827 struct request_queue *q,
828 struct bio *bio, int rw)
831 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
833 struct blk_trace *bt = q->blk_trace;
836 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
841 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
843 struct blk_trace *bt = q->blk_trace;
846 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
849 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
851 struct blk_trace *bt = q->blk_trace;
854 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
855 __be64 rpdu = cpu_to_be64(pdu);
857 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
858 sizeof(rpdu), &rpdu);
862 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
864 struct blk_trace *bt = q->blk_trace;
867 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
868 __be64 rpdu = cpu_to_be64(pdu);
870 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
871 sizeof(rpdu), &rpdu);
875 static void blk_add_trace_split(void *ignore,
876 struct request_queue *q, struct bio *bio,
879 struct blk_trace *bt = q->blk_trace;
882 __be64 rpdu = cpu_to_be64(pdu);
884 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
885 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
886 sizeof(rpdu), &rpdu);
891 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
892 * @ignore: trace callback data parameter (not used)
893 * @q: queue the io is for
894 * @bio: the source bio
895 * @dev: target device
896 * @from: source sector
899 * Device mapper or raid target sometimes need to split a bio because
900 * it spans a stripe (or similar). Add a trace for that action.
903 static void blk_add_trace_bio_remap(void *ignore,
904 struct request_queue *q, struct bio *bio,
905 dev_t dev, sector_t from)
907 struct blk_trace *bt = q->blk_trace;
908 struct blk_io_trace_remap r;
913 r.device_from = cpu_to_be32(dev);
914 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
915 r.sector_from = cpu_to_be64(from);
917 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
918 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
923 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
924 * @ignore: trace callback data parameter (not used)
925 * @q: queue the io is for
926 * @rq: the source request
927 * @dev: target device
928 * @from: source sector
931 * Device mapper remaps request to other devices.
932 * Add a trace for that action.
935 static void blk_add_trace_rq_remap(void *ignore,
936 struct request_queue *q,
937 struct request *rq, dev_t dev,
940 struct blk_trace *bt = q->blk_trace;
941 struct blk_io_trace_remap r;
946 r.device_from = cpu_to_be32(dev);
947 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
948 r.sector_from = cpu_to_be64(from);
950 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
951 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
956 * blk_add_driver_data - Add binary message with driver-specific data
957 * @q: queue the io is for
959 * @data: driver-specific data
960 * @len: length of driver-specific data
963 * Some drivers might want to write driver-specific data per request.
966 void blk_add_driver_data(struct request_queue *q,
968 void *data, size_t len)
970 struct blk_trace *bt = q->blk_trace;
975 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
976 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
977 BLK_TA_DRV_DATA, rq->errors, len, data);
979 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
980 BLK_TA_DRV_DATA, rq->errors, len, data);
982 EXPORT_SYMBOL_GPL(blk_add_driver_data);
984 static void blk_register_tracepoints(void)
988 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
990 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
992 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
994 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
996 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
998 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1000 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1002 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1004 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1006 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1008 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1010 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1012 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1014 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1016 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1018 ret = register_trace_block_split(blk_add_trace_split, NULL);
1020 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1022 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1026 static void blk_unregister_tracepoints(void)
1028 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1029 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1030 unregister_trace_block_split(blk_add_trace_split, NULL);
1031 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1032 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1033 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1034 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1035 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1036 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1037 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1038 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1039 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1040 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1041 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1042 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1043 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1044 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1045 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1047 tracepoint_synchronize_unregister();
1051 * struct blk_io_tracer formatting routines
1054 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1057 int tc = t->action >> BLK_TC_SHIFT;
1059 if (t->action == BLK_TN_MESSAGE) {
1064 if (tc & BLK_TC_DISCARD)
1066 else if (tc & BLK_TC_WRITE)
1073 if (tc & BLK_TC_AHEAD)
1075 if (tc & BLK_TC_BARRIER)
1077 if (tc & BLK_TC_SYNC)
1079 if (tc & BLK_TC_META)
1086 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1088 return (const struct blk_io_trace *)ent;
1091 static inline const void *pdu_start(const struct trace_entry *ent)
1093 return te_blk_io_trace(ent) + 1;
1096 static inline u32 t_action(const struct trace_entry *ent)
1098 return te_blk_io_trace(ent)->action;
1101 static inline u32 t_bytes(const struct trace_entry *ent)
1103 return te_blk_io_trace(ent)->bytes;
1106 static inline u32 t_sec(const struct trace_entry *ent)
1108 return te_blk_io_trace(ent)->bytes >> 9;
1111 static inline unsigned long long t_sector(const struct trace_entry *ent)
1113 return te_blk_io_trace(ent)->sector;
1116 static inline __u16 t_error(const struct trace_entry *ent)
1118 return te_blk_io_trace(ent)->error;
1121 static __u64 get_pdu_int(const struct trace_entry *ent)
1123 const __u64 *val = pdu_start(ent);
1124 return be64_to_cpu(*val);
1127 static void get_pdu_remap(const struct trace_entry *ent,
1128 struct blk_io_trace_remap *r)
1130 const struct blk_io_trace_remap *__r = pdu_start(ent);
1131 __u64 sector_from = __r->sector_from;
1133 r->device_from = be32_to_cpu(__r->device_from);
1134 r->device_to = be32_to_cpu(__r->device_to);
1135 r->sector_from = be64_to_cpu(sector_from);
1138 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1140 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1143 unsigned long long ts = iter->ts;
1144 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1145 unsigned secs = (unsigned long)ts;
1146 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1150 return trace_seq_printf(&iter->seq,
1151 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1152 MAJOR(t->device), MINOR(t->device), iter->cpu,
1153 secs, nsec_rem, iter->ent->pid, act, rwbs);
1156 static int blk_log_action(struct trace_iterator *iter, const char *act)
1159 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1162 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1163 MAJOR(t->device), MINOR(t->device), act, rwbs);
1166 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1168 const unsigned char *pdu_buf;
1172 pdu_buf = pdu_start(ent);
1173 pdu_len = te_blk_io_trace(ent)->pdu_len;
1178 /* find the last zero that needs to be printed */
1179 for (end = pdu_len - 1; end >= 0; end--)
1184 if (!trace_seq_putc(s, '('))
1187 for (i = 0; i < pdu_len; i++) {
1189 ret = trace_seq_printf(s, "%s%02x",
1190 i == 0 ? "" : " ", pdu_buf[i]);
1195 * stop when the rest is just zeroes and indicate so
1196 * with a ".." appended
1198 if (i == end && end != pdu_len - 1)
1199 return trace_seq_puts(s, " ..) ");
1202 return trace_seq_puts(s, ") ");
1205 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1207 char cmd[TASK_COMM_LEN];
1209 trace_find_cmdline(ent->pid, cmd);
1211 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1214 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1217 ret = blk_log_dump_pdu(s, ent);
1220 return trace_seq_printf(s, "[%s]\n", cmd);
1223 return trace_seq_printf(s, "%llu + %u [%s]\n",
1224 t_sector(ent), t_sec(ent), cmd);
1225 return trace_seq_printf(s, "[%s]\n", cmd);
1229 static int blk_log_with_error(struct trace_seq *s,
1230 const struct trace_entry *ent)
1232 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1235 ret = blk_log_dump_pdu(s, ent);
1237 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1241 return trace_seq_printf(s, "%llu + %u [%d]\n",
1243 t_sec(ent), t_error(ent));
1244 return trace_seq_printf(s, "%llu [%d]\n",
1245 t_sector(ent), t_error(ent));
1249 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1251 struct blk_io_trace_remap r = { .device_from = 0, };
1253 get_pdu_remap(ent, &r);
1254 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1255 t_sector(ent), t_sec(ent),
1256 MAJOR(r.device_from), MINOR(r.device_from),
1257 (unsigned long long)r.sector_from);
1260 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1262 char cmd[TASK_COMM_LEN];
1264 trace_find_cmdline(ent->pid, cmd);
1266 return trace_seq_printf(s, "[%s]\n", cmd);
1269 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1271 char cmd[TASK_COMM_LEN];
1273 trace_find_cmdline(ent->pid, cmd);
1275 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1278 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1280 char cmd[TASK_COMM_LEN];
1282 trace_find_cmdline(ent->pid, cmd);
1284 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1285 get_pdu_int(ent), cmd);
1288 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1291 const struct blk_io_trace *t = te_blk_io_trace(ent);
1293 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1295 return trace_seq_putc(s, '\n');
1300 * struct tracer operations
1303 static void blk_tracer_print_header(struct seq_file *m)
1305 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1307 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1311 static void blk_tracer_start(struct trace_array *tr)
1313 blk_tracer_enabled = true;
1316 static int blk_tracer_init(struct trace_array *tr)
1319 blk_tracer_start(tr);
1323 static void blk_tracer_stop(struct trace_array *tr)
1325 blk_tracer_enabled = false;
1328 static void blk_tracer_reset(struct trace_array *tr)
1330 blk_tracer_stop(tr);
1333 static const struct {
1335 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1337 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1338 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1339 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1340 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1341 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1342 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1343 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1344 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1345 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1346 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1347 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1348 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1349 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1350 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1351 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1354 static enum print_line_t print_one_line(struct trace_iterator *iter,
1357 struct trace_seq *s = &iter->seq;
1358 const struct blk_io_trace *t;
1362 blk_log_action_t *log_action;
1364 t = te_blk_io_trace(iter->ent);
1365 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1366 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1367 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1369 if (t->action == BLK_TN_MESSAGE) {
1370 ret = log_action(iter, long_act ? "message" : "m");
1372 ret = blk_log_msg(s, iter->ent);
1376 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1377 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1379 ret = log_action(iter, what2act[what].act[long_act]);
1381 ret = what2act[what].print(s, iter->ent);
1384 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1387 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1388 int flags, struct trace_event *event)
1390 return print_one_line(iter, false);
1393 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1395 struct trace_seq *s = &iter->seq;
1396 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1397 const int offset = offsetof(struct blk_io_trace, sector);
1398 struct blk_io_trace old = {
1399 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1403 if (!trace_seq_putmem(s, &old, offset))
1405 return trace_seq_putmem(s, &t->sector,
1406 sizeof(old) - offset + t->pdu_len);
1409 static enum print_line_t
1410 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1411 struct trace_event *event)
1413 return blk_trace_synthesize_old_trace(iter) ?
1414 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1417 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1419 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1420 return TRACE_TYPE_UNHANDLED;
1422 return print_one_line(iter, true);
1425 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1427 /* don't output context-info for blk_classic output */
1428 if (bit == TRACE_BLK_OPT_CLASSIC) {
1430 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1432 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1437 static struct tracer blk_tracer __read_mostly = {
1439 .init = blk_tracer_init,
1440 .reset = blk_tracer_reset,
1441 .start = blk_tracer_start,
1442 .stop = blk_tracer_stop,
1443 .print_header = blk_tracer_print_header,
1444 .print_line = blk_tracer_print_line,
1445 .flags = &blk_tracer_flags,
1446 .set_flag = blk_tracer_set_flag,
1449 static struct trace_event_functions trace_blk_event_funcs = {
1450 .trace = blk_trace_event_print,
1451 .binary = blk_trace_event_print_binary,
1454 static struct trace_event trace_blk_event = {
1456 .funcs = &trace_blk_event_funcs,
1459 static int __init init_blk_tracer(void)
1461 if (!register_ftrace_event(&trace_blk_event)) {
1462 pr_warning("Warning: could not register block events\n");
1466 if (register_tracer(&blk_tracer) != 0) {
1467 pr_warning("Warning: could not register the block tracer\n");
1468 unregister_ftrace_event(&trace_blk_event);
1475 device_initcall(init_blk_tracer);
1477 static int blk_trace_remove_queue(struct request_queue *q)
1479 struct blk_trace *bt;
1481 bt = xchg(&q->blk_trace, NULL);
1485 if (atomic_dec_and_test(&blk_probes_ref))
1486 blk_unregister_tracepoints();
1493 * Setup everything required to start tracing
1495 static int blk_trace_setup_queue(struct request_queue *q,
1496 struct block_device *bdev)
1498 struct blk_trace *old_bt, *bt = NULL;
1501 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1505 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1509 bt->dev = bdev->bd_dev;
1510 bt->act_mask = (u16)-1;
1512 blk_trace_setup_lba(bt, bdev);
1514 old_bt = xchg(&q->blk_trace, bt);
1515 if (old_bt != NULL) {
1516 (void)xchg(&q->blk_trace, old_bt);
1521 if (atomic_inc_return(&blk_probes_ref) == 1)
1522 blk_register_tracepoints();
1531 * sysfs interface to enable and configure tracing
1534 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1535 struct device_attribute *attr,
1537 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1538 struct device_attribute *attr,
1539 const char *buf, size_t count);
1540 #define BLK_TRACE_DEVICE_ATTR(_name) \
1541 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1542 sysfs_blk_trace_attr_show, \
1543 sysfs_blk_trace_attr_store)
1545 static BLK_TRACE_DEVICE_ATTR(enable);
1546 static BLK_TRACE_DEVICE_ATTR(act_mask);
1547 static BLK_TRACE_DEVICE_ATTR(pid);
1548 static BLK_TRACE_DEVICE_ATTR(start_lba);
1549 static BLK_TRACE_DEVICE_ATTR(end_lba);
1551 static struct attribute *blk_trace_attrs[] = {
1552 &dev_attr_enable.attr,
1553 &dev_attr_act_mask.attr,
1555 &dev_attr_start_lba.attr,
1556 &dev_attr_end_lba.attr,
1560 struct attribute_group blk_trace_attr_group = {
1562 .attrs = blk_trace_attrs,
1565 static const struct {
1569 { BLK_TC_READ, "read" },
1570 { BLK_TC_WRITE, "write" },
1571 { BLK_TC_BARRIER, "barrier" },
1572 { BLK_TC_SYNC, "sync" },
1573 { BLK_TC_QUEUE, "queue" },
1574 { BLK_TC_REQUEUE, "requeue" },
1575 { BLK_TC_ISSUE, "issue" },
1576 { BLK_TC_COMPLETE, "complete" },
1577 { BLK_TC_FS, "fs" },
1578 { BLK_TC_PC, "pc" },
1579 { BLK_TC_AHEAD, "ahead" },
1580 { BLK_TC_META, "meta" },
1581 { BLK_TC_DISCARD, "discard" },
1582 { BLK_TC_DRV_DATA, "drv_data" },
1585 static int blk_trace_str2mask(const char *str)
1589 char *buf, *s, *token;
1591 buf = kstrdup(str, GFP_KERNEL);
1597 token = strsep(&s, ",");
1604 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1605 if (strcasecmp(token, mask_maps[i].str) == 0) {
1606 mask |= mask_maps[i].mask;
1610 if (i == ARRAY_SIZE(mask_maps)) {
1620 static ssize_t blk_trace_mask2str(char *buf, int mask)
1625 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1626 if (mask & mask_maps[i].mask) {
1627 p += sprintf(p, "%s%s",
1628 (p == buf) ? "" : ",", mask_maps[i].str);
1636 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1638 if (bdev->bd_disk == NULL)
1641 return bdev_get_queue(bdev);
1644 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1645 struct device_attribute *attr,
1648 struct hd_struct *p = dev_to_part(dev);
1649 struct request_queue *q;
1650 struct block_device *bdev;
1651 ssize_t ret = -ENXIO;
1653 bdev = bdget(part_devt(p));
1657 q = blk_trace_get_queue(bdev);
1661 mutex_lock(&bdev->bd_mutex);
1663 if (attr == &dev_attr_enable) {
1664 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1665 goto out_unlock_bdev;
1668 if (q->blk_trace == NULL)
1669 ret = sprintf(buf, "disabled\n");
1670 else if (attr == &dev_attr_act_mask)
1671 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1672 else if (attr == &dev_attr_pid)
1673 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1674 else if (attr == &dev_attr_start_lba)
1675 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1676 else if (attr == &dev_attr_end_lba)
1677 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1680 mutex_unlock(&bdev->bd_mutex);
1687 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1688 struct device_attribute *attr,
1689 const char *buf, size_t count)
1691 struct block_device *bdev;
1692 struct request_queue *q;
1693 struct hd_struct *p;
1695 ssize_t ret = -EINVAL;
1700 if (attr == &dev_attr_act_mask) {
1701 if (sscanf(buf, "%llx", &value) != 1) {
1702 /* Assume it is a list of trace category names */
1703 ret = blk_trace_str2mask(buf);
1708 } else if (sscanf(buf, "%llu", &value) != 1)
1713 p = dev_to_part(dev);
1714 bdev = bdget(part_devt(p));
1718 q = blk_trace_get_queue(bdev);
1722 mutex_lock(&bdev->bd_mutex);
1724 if (attr == &dev_attr_enable) {
1726 ret = blk_trace_setup_queue(q, bdev);
1728 ret = blk_trace_remove_queue(q);
1729 goto out_unlock_bdev;
1733 if (q->blk_trace == NULL)
1734 ret = blk_trace_setup_queue(q, bdev);
1737 if (attr == &dev_attr_act_mask)
1738 q->blk_trace->act_mask = value;
1739 else if (attr == &dev_attr_pid)
1740 q->blk_trace->pid = value;
1741 else if (attr == &dev_attr_start_lba)
1742 q->blk_trace->start_lba = value;
1743 else if (attr == &dev_attr_end_lba)
1744 q->blk_trace->end_lba = value;
1748 mutex_unlock(&bdev->bd_mutex);
1752 return ret ? ret : count;
1755 int blk_trace_init_sysfs(struct device *dev)
1757 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1760 void blk_trace_remove_sysfs(struct device *dev)
1762 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1765 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1767 #ifdef CONFIG_EVENT_TRACING
1769 void blk_dump_cmd(char *buf, struct request *rq)
1772 int len = rq->cmd_len;
1773 unsigned char *cmd = rq->cmd;
1775 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1780 for (end = len - 1; end >= 0; end--)
1785 for (i = 0; i < len; i++) {
1786 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1787 if (i == end && end != len - 1) {
1788 sprintf(buf, " ..");
1794 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1800 else if (rw & REQ_DISCARD)
1807 if (rw & REQ_RAHEAD)
1813 if (rw & REQ_SECURE)
1819 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1821 int rw = rq->cmd_flags & 0x03;
1824 if (rq->cmd_flags & REQ_DISCARD)
1827 if (rq->cmd_flags & REQ_SECURE)
1830 bytes = blk_rq_bytes(rq);
1832 blk_fill_rwbs(rwbs, rw, bytes);
1835 #endif /* CONFIG_EVENT_TRACING */