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/debugfs.h>
25 #include <linux/time.h>
26 #include <trace/block.h>
27 #include <linux/uaccess.h>
28 #include "trace_output.h"
30 static unsigned int blktrace_seq __read_mostly
= 1;
32 static struct trace_array
*blk_tr
;
33 static bool blk_tracer_enabled __read_mostly
;
35 /* Select an alternative, minimalistic output than the original one */
36 #define TRACE_BLK_OPT_CLASSIC 0x1
38 static struct tracer_opt blk_tracer_opts
[] = {
39 /* Default disable the minimalistic output */
40 { TRACER_OPT(blk_classic
, TRACE_BLK_OPT_CLASSIC
) },
44 static struct tracer_flags blk_tracer_flags
= {
46 .opts
= blk_tracer_opts
,
49 /* Global reference count of probes */
50 static atomic_t blk_probes_ref
= ATOMIC_INIT(0);
52 static void blk_register_tracepoints(void);
53 static void blk_unregister_tracepoints(void);
56 * Send out a notify message.
58 static void trace_note(struct blk_trace
*bt
, pid_t pid
, int action
,
59 const void *data
, size_t len
)
61 struct blk_io_trace
*t
;
66 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + len
);
68 const int cpu
= smp_processor_id();
70 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
71 t
->time
= ktime_to_ns(ktime_get());
77 memcpy((void *) t
+ sizeof(*t
), data
, len
);
82 * Send out a notify for this process, if we haven't done so since a trace
85 static void trace_note_tsk(struct blk_trace
*bt
, struct task_struct
*tsk
)
87 tsk
->btrace_seq
= blktrace_seq
;
88 trace_note(bt
, tsk
->pid
, BLK_TN_PROCESS
, tsk
->comm
, sizeof(tsk
->comm
));
91 static void trace_note_time(struct blk_trace
*bt
)
98 words
[0] = now
.tv_sec
;
99 words
[1] = now
.tv_nsec
;
101 local_irq_save(flags
);
102 trace_note(bt
, 0, BLK_TN_TIMESTAMP
, words
, sizeof(words
));
103 local_irq_restore(flags
);
106 void __trace_note_message(struct blk_trace
*bt
, const char *fmt
, ...)
115 ftrace_vprintk(fmt
, args
);
123 local_irq_save(flags
);
124 buf
= per_cpu_ptr(bt
->msg_data
, smp_processor_id());
126 n
= vscnprintf(buf
, BLK_TN_MAX_MSG
, fmt
, args
);
129 trace_note(bt
, 0, BLK_TN_MESSAGE
, buf
, n
);
130 local_irq_restore(flags
);
132 EXPORT_SYMBOL_GPL(__trace_note_message
);
134 static int act_log_check(struct blk_trace
*bt
, u32 what
, sector_t sector
,
137 if (((bt
->act_mask
<< BLK_TC_SHIFT
) & what
) == 0)
139 if (sector
< bt
->start_lba
|| sector
> bt
->end_lba
)
141 if (bt
->pid
&& pid
!= bt
->pid
)
148 * Data direction bit lookup
150 static const u32 ddir_act
[2] = { BLK_TC_ACT(BLK_TC_READ
),
151 BLK_TC_ACT(BLK_TC_WRITE
) };
153 /* The ilog2() calls fall out because they're constant */
154 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
155 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
158 * The worker for the various blk_add_trace*() types. Fills out a
159 * blk_io_trace structure and places it in a per-cpu subbuffer.
161 static void __blk_add_trace(struct blk_trace
*bt
, sector_t sector
, int bytes
,
162 int rw
, u32 what
, int error
, int pdu_len
, void *pdu_data
)
164 struct task_struct
*tsk
= current
;
165 struct ring_buffer_event
*event
= NULL
;
166 struct blk_io_trace
*t
;
167 unsigned long flags
= 0;
168 unsigned long *sequence
;
172 if (unlikely(bt
->trace_state
!= Blktrace_running
||
173 !blk_tracer_enabled
))
176 what
|= ddir_act
[rw
& WRITE
];
177 what
|= MASK_TC_BIT(rw
, BARRIER
);
178 what
|= MASK_TC_BIT(rw
, SYNCIO
);
179 what
|= MASK_TC_BIT(rw
, AHEAD
);
180 what
|= MASK_TC_BIT(rw
, META
);
181 what
|= MASK_TC_BIT(rw
, DISCARD
);
184 if (unlikely(act_log_check(bt
, what
, sector
, pid
)))
186 cpu
= raw_smp_processor_id();
189 tracing_record_cmdline(current
);
191 pc
= preempt_count();
192 event
= trace_buffer_lock_reserve(blk_tr
, TRACE_BLK
,
193 sizeof(*t
) + pdu_len
,
197 t
= ring_buffer_event_data(event
);
202 * A word about the locking here - we disable interrupts to reserve
203 * some space in the relay per-cpu buffer, to prevent an irq
204 * from coming in and stepping on our toes.
206 local_irq_save(flags
);
208 if (unlikely(tsk
->btrace_seq
!= blktrace_seq
))
209 trace_note_tsk(bt
, tsk
);
211 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + pdu_len
);
213 sequence
= per_cpu_ptr(bt
->sequence
, cpu
);
215 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
216 t
->sequence
= ++(*sequence
);
217 t
->time
= ktime_to_ns(ktime_get());
220 * These two are not needed in ftrace as they are in the
221 * generic trace_entry, filled by tracing_generic_entry_update,
222 * but for the trace_event->bin() synthesizer benefit we do it
233 t
->pdu_len
= pdu_len
;
236 memcpy((void *) t
+ sizeof(*t
), pdu_data
, pdu_len
);
239 trace_buffer_unlock_commit(blk_tr
, event
, 0, pc
);
244 local_irq_restore(flags
);
247 static struct dentry
*blk_tree_root
;
248 static DEFINE_MUTEX(blk_tree_mutex
);
250 static void blk_trace_cleanup(struct blk_trace
*bt
)
252 debugfs_remove(bt
->msg_file
);
253 debugfs_remove(bt
->dropped_file
);
254 relay_close(bt
->rchan
);
255 free_percpu(bt
->sequence
);
256 free_percpu(bt
->msg_data
);
258 if (atomic_dec_and_test(&blk_probes_ref
))
259 blk_unregister_tracepoints();
262 int blk_trace_remove(struct request_queue
*q
)
264 struct blk_trace
*bt
;
266 bt
= xchg(&q
->blk_trace
, NULL
);
270 if (bt
->trace_state
== Blktrace_setup
||
271 bt
->trace_state
== Blktrace_stopped
)
272 blk_trace_cleanup(bt
);
276 EXPORT_SYMBOL_GPL(blk_trace_remove
);
278 static int blk_dropped_open(struct inode
*inode
, struct file
*filp
)
280 filp
->private_data
= inode
->i_private
;
285 static ssize_t
blk_dropped_read(struct file
*filp
, char __user
*buffer
,
286 size_t count
, loff_t
*ppos
)
288 struct blk_trace
*bt
= filp
->private_data
;
291 snprintf(buf
, sizeof(buf
), "%u\n", atomic_read(&bt
->dropped
));
293 return simple_read_from_buffer(buffer
, count
, ppos
, buf
, strlen(buf
));
296 static const struct file_operations blk_dropped_fops
= {
297 .owner
= THIS_MODULE
,
298 .open
= blk_dropped_open
,
299 .read
= blk_dropped_read
,
302 static int blk_msg_open(struct inode
*inode
, struct file
*filp
)
304 filp
->private_data
= inode
->i_private
;
309 static ssize_t
blk_msg_write(struct file
*filp
, const char __user
*buffer
,
310 size_t count
, loff_t
*ppos
)
313 struct blk_trace
*bt
;
315 if (count
> BLK_TN_MAX_MSG
)
318 msg
= kmalloc(count
, GFP_KERNEL
);
322 if (copy_from_user(msg
, buffer
, count
)) {
327 bt
= filp
->private_data
;
328 __trace_note_message(bt
, "%s", msg
);
334 static const struct file_operations blk_msg_fops
= {
335 .owner
= THIS_MODULE
,
336 .open
= blk_msg_open
,
337 .write
= blk_msg_write
,
341 * Keep track of how many times we encountered a full subbuffer, to aid
342 * the user space app in telling how many lost events there were.
344 static int blk_subbuf_start_callback(struct rchan_buf
*buf
, void *subbuf
,
345 void *prev_subbuf
, size_t prev_padding
)
347 struct blk_trace
*bt
;
349 if (!relay_buf_full(buf
))
352 bt
= buf
->chan
->private_data
;
353 atomic_inc(&bt
->dropped
);
357 static int blk_remove_buf_file_callback(struct dentry
*dentry
)
359 struct dentry
*parent
= dentry
->d_parent
;
360 debugfs_remove(dentry
);
363 * this will fail for all but the last file, but that is ok. what we
364 * care about is the top level buts->name directory going away, when
365 * the last trace file is gone. Then we don't have to rmdir() that
366 * manually on trace stop, so it nicely solves the issue with
367 * force killing of running traces.
370 debugfs_remove(parent
);
374 static struct dentry
*blk_create_buf_file_callback(const char *filename
,
375 struct dentry
*parent
,
377 struct rchan_buf
*buf
,
380 return debugfs_create_file(filename
, mode
, parent
, buf
,
381 &relay_file_operations
);
384 static struct rchan_callbacks blk_relay_callbacks
= {
385 .subbuf_start
= blk_subbuf_start_callback
,
386 .create_buf_file
= blk_create_buf_file_callback
,
387 .remove_buf_file
= blk_remove_buf_file_callback
,
391 * Setup everything required to start tracing
393 int do_blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
394 struct blk_user_trace_setup
*buts
)
396 struct blk_trace
*old_bt
, *bt
= NULL
;
397 struct dentry
*dir
= NULL
;
400 if (!buts
->buf_size
|| !buts
->buf_nr
)
403 strncpy(buts
->name
, name
, BLKTRACE_BDEV_SIZE
);
404 buts
->name
[BLKTRACE_BDEV_SIZE
- 1] = '\0';
407 * some device names have larger paths - convert the slashes
408 * to underscores for this to work as expected
410 for (i
= 0; i
< strlen(buts
->name
); i
++)
411 if (buts
->name
[i
] == '/')
415 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
419 bt
->sequence
= alloc_percpu(unsigned long);
423 bt
->msg_data
= __alloc_percpu(BLK_TN_MAX_MSG
, __alignof__(char));
429 if (!blk_tree_root
) {
430 blk_tree_root
= debugfs_create_dir("block", NULL
);
435 dir
= debugfs_create_dir(buts
->name
, blk_tree_root
);
442 atomic_set(&bt
->dropped
, 0);
445 bt
->dropped_file
= debugfs_create_file("dropped", 0444, dir
, bt
,
447 if (!bt
->dropped_file
)
450 bt
->msg_file
= debugfs_create_file("msg", 0222, dir
, bt
, &blk_msg_fops
);
454 bt
->rchan
= relay_open("trace", dir
, buts
->buf_size
,
455 buts
->buf_nr
, &blk_relay_callbacks
, bt
);
459 bt
->act_mask
= buts
->act_mask
;
461 bt
->act_mask
= (u16
) -1;
463 bt
->start_lba
= buts
->start_lba
;
464 bt
->end_lba
= buts
->end_lba
;
469 bt
->trace_state
= Blktrace_setup
;
472 old_bt
= xchg(&q
->blk_trace
, bt
);
474 (void) xchg(&q
->blk_trace
, old_bt
);
478 if (atomic_add_return(1, &blk_probes_ref
) == 1)
479 blk_register_tracepoints();
485 debugfs_remove(bt
->msg_file
);
486 if (bt
->dropped_file
)
487 debugfs_remove(bt
->dropped_file
);
488 free_percpu(bt
->sequence
);
489 free_percpu(bt
->msg_data
);
491 relay_close(bt
->rchan
);
497 int blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
500 struct blk_user_trace_setup buts
;
503 ret
= copy_from_user(&buts
, arg
, sizeof(buts
));
507 ret
= do_blk_trace_setup(q
, name
, dev
, &buts
);
511 if (copy_to_user(arg
, &buts
, sizeof(buts
)))
516 EXPORT_SYMBOL_GPL(blk_trace_setup
);
518 int blk_trace_startstop(struct request_queue
*q
, int start
)
521 struct blk_trace
*bt
= q
->blk_trace
;
527 * For starting a trace, we can transition from a setup or stopped
528 * trace. For stopping a trace, the state must be running
532 if (bt
->trace_state
== Blktrace_setup
||
533 bt
->trace_state
== Blktrace_stopped
) {
536 bt
->trace_state
= Blktrace_running
;
542 if (bt
->trace_state
== Blktrace_running
) {
543 bt
->trace_state
= Blktrace_stopped
;
544 relay_flush(bt
->rchan
);
551 EXPORT_SYMBOL_GPL(blk_trace_startstop
);
554 * blk_trace_ioctl: - handle the ioctls associated with tracing
555 * @bdev: the block device
556 * @cmd: the ioctl cmd
557 * @arg: the argument data, if any
560 int blk_trace_ioctl(struct block_device
*bdev
, unsigned cmd
, char __user
*arg
)
562 struct request_queue
*q
;
564 char b
[BDEVNAME_SIZE
];
566 q
= bdev_get_queue(bdev
);
570 mutex_lock(&bdev
->bd_mutex
);
575 ret
= blk_trace_setup(q
, b
, bdev
->bd_dev
, arg
);
580 ret
= blk_trace_startstop(q
, start
);
582 case BLKTRACETEARDOWN
:
583 ret
= blk_trace_remove(q
);
590 mutex_unlock(&bdev
->bd_mutex
);
595 * blk_trace_shutdown: - stop and cleanup trace structures
596 * @q: the request queue associated with the device
599 void blk_trace_shutdown(struct request_queue
*q
)
602 blk_trace_startstop(q
, 0);
612 * blk_add_trace_rq - Add a trace for a request oriented action
613 * @q: queue the io is for
614 * @rq: the source request
618 * Records an action against a request. Will log the bio offset + size.
621 static void blk_add_trace_rq(struct request_queue
*q
, struct request
*rq
,
624 struct blk_trace
*bt
= q
->blk_trace
;
625 int rw
= rq
->cmd_flags
& 0x03;
630 if (blk_discard_rq(rq
))
631 rw
|= (1 << BIO_RW_DISCARD
);
633 if (blk_pc_request(rq
)) {
634 what
|= BLK_TC_ACT(BLK_TC_PC
);
635 __blk_add_trace(bt
, 0, rq
->data_len
, rw
, what
, rq
->errors
,
636 sizeof(rq
->cmd
), rq
->cmd
);
638 what
|= BLK_TC_ACT(BLK_TC_FS
);
639 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
640 rw
, what
, rq
->errors
, 0, NULL
);
644 static void blk_add_trace_rq_abort(struct request_queue
*q
, struct request
*rq
)
646 blk_add_trace_rq(q
, rq
, BLK_TA_ABORT
);
649 static void blk_add_trace_rq_insert(struct request_queue
*q
, struct request
*rq
)
651 blk_add_trace_rq(q
, rq
, BLK_TA_INSERT
);
654 static void blk_add_trace_rq_issue(struct request_queue
*q
, struct request
*rq
)
656 blk_add_trace_rq(q
, rq
, BLK_TA_ISSUE
);
659 static void blk_add_trace_rq_requeue(struct request_queue
*q
,
662 blk_add_trace_rq(q
, rq
, BLK_TA_REQUEUE
);
665 static void blk_add_trace_rq_complete(struct request_queue
*q
,
668 blk_add_trace_rq(q
, rq
, BLK_TA_COMPLETE
);
672 * blk_add_trace_bio - Add a trace for a bio oriented action
673 * @q: queue the io is for
674 * @bio: the source bio
678 * Records an action against a bio. Will log the bio offset + size.
681 static void blk_add_trace_bio(struct request_queue
*q
, struct bio
*bio
,
684 struct blk_trace
*bt
= q
->blk_trace
;
689 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
, what
,
690 !bio_flagged(bio
, BIO_UPTODATE
), 0, NULL
);
693 static void blk_add_trace_bio_bounce(struct request_queue
*q
, struct bio
*bio
)
695 blk_add_trace_bio(q
, bio
, BLK_TA_BOUNCE
);
698 static void blk_add_trace_bio_complete(struct request_queue
*q
, struct bio
*bio
)
700 blk_add_trace_bio(q
, bio
, BLK_TA_COMPLETE
);
703 static void blk_add_trace_bio_backmerge(struct request_queue
*q
,
706 blk_add_trace_bio(q
, bio
, BLK_TA_BACKMERGE
);
709 static void blk_add_trace_bio_frontmerge(struct request_queue
*q
,
712 blk_add_trace_bio(q
, bio
, BLK_TA_FRONTMERGE
);
715 static void blk_add_trace_bio_queue(struct request_queue
*q
, struct bio
*bio
)
717 blk_add_trace_bio(q
, bio
, BLK_TA_QUEUE
);
720 static void blk_add_trace_getrq(struct request_queue
*q
,
721 struct bio
*bio
, int rw
)
724 blk_add_trace_bio(q
, bio
, BLK_TA_GETRQ
);
726 struct blk_trace
*bt
= q
->blk_trace
;
729 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_GETRQ
, 0, 0, NULL
);
734 static void blk_add_trace_sleeprq(struct request_queue
*q
,
735 struct bio
*bio
, int rw
)
738 blk_add_trace_bio(q
, bio
, BLK_TA_SLEEPRQ
);
740 struct blk_trace
*bt
= q
->blk_trace
;
743 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_SLEEPRQ
,
748 static void blk_add_trace_plug(struct request_queue
*q
)
750 struct blk_trace
*bt
= q
->blk_trace
;
753 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_PLUG
, 0, 0, NULL
);
756 static void blk_add_trace_unplug_io(struct request_queue
*q
)
758 struct blk_trace
*bt
= q
->blk_trace
;
761 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
762 __be64 rpdu
= cpu_to_be64(pdu
);
764 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_IO
, 0,
765 sizeof(rpdu
), &rpdu
);
769 static void blk_add_trace_unplug_timer(struct request_queue
*q
)
771 struct blk_trace
*bt
= q
->blk_trace
;
774 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
775 __be64 rpdu
= cpu_to_be64(pdu
);
777 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_TIMER
, 0,
778 sizeof(rpdu
), &rpdu
);
782 static void blk_add_trace_split(struct request_queue
*q
, struct bio
*bio
,
785 struct blk_trace
*bt
= q
->blk_trace
;
788 __be64 rpdu
= cpu_to_be64(pdu
);
790 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
,
791 BLK_TA_SPLIT
, !bio_flagged(bio
, BIO_UPTODATE
),
792 sizeof(rpdu
), &rpdu
);
797 * blk_add_trace_remap - Add a trace for a remap operation
798 * @q: queue the io is for
799 * @bio: the source bio
800 * @dev: target device
801 * @from: source sector
805 * Device mapper or raid target sometimes need to split a bio because
806 * it spans a stripe (or similar). Add a trace for that action.
809 static void blk_add_trace_remap(struct request_queue
*q
, struct bio
*bio
,
810 dev_t dev
, sector_t from
, sector_t to
)
812 struct blk_trace
*bt
= q
->blk_trace
;
813 struct blk_io_trace_remap r
;
818 r
.device
= cpu_to_be32(dev
);
819 r
.device_from
= cpu_to_be32(bio
->bi_bdev
->bd_dev
);
820 r
.sector
= cpu_to_be64(to
);
822 __blk_add_trace(bt
, from
, bio
->bi_size
, bio
->bi_rw
, BLK_TA_REMAP
,
823 !bio_flagged(bio
, BIO_UPTODATE
), sizeof(r
), &r
);
827 * blk_add_driver_data - Add binary message with driver-specific data
828 * @q: queue the io is for
830 * @data: driver-specific data
831 * @len: length of driver-specific data
834 * Some drivers might want to write driver-specific data per request.
837 void blk_add_driver_data(struct request_queue
*q
,
839 void *data
, size_t len
)
841 struct blk_trace
*bt
= q
->blk_trace
;
846 if (blk_pc_request(rq
))
847 __blk_add_trace(bt
, 0, rq
->data_len
, 0, BLK_TA_DRV_DATA
,
848 rq
->errors
, len
, data
);
850 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
851 0, BLK_TA_DRV_DATA
, rq
->errors
, len
, data
);
853 EXPORT_SYMBOL_GPL(blk_add_driver_data
);
855 static void blk_register_tracepoints(void)
859 ret
= register_trace_block_rq_abort(blk_add_trace_rq_abort
);
861 ret
= register_trace_block_rq_insert(blk_add_trace_rq_insert
);
863 ret
= register_trace_block_rq_issue(blk_add_trace_rq_issue
);
865 ret
= register_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
867 ret
= register_trace_block_rq_complete(blk_add_trace_rq_complete
);
869 ret
= register_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
871 ret
= register_trace_block_bio_complete(blk_add_trace_bio_complete
);
873 ret
= register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
875 ret
= register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
877 ret
= register_trace_block_bio_queue(blk_add_trace_bio_queue
);
879 ret
= register_trace_block_getrq(blk_add_trace_getrq
);
881 ret
= register_trace_block_sleeprq(blk_add_trace_sleeprq
);
883 ret
= register_trace_block_plug(blk_add_trace_plug
);
885 ret
= register_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
887 ret
= register_trace_block_unplug_io(blk_add_trace_unplug_io
);
889 ret
= register_trace_block_split(blk_add_trace_split
);
891 ret
= register_trace_block_remap(blk_add_trace_remap
);
895 static void blk_unregister_tracepoints(void)
897 unregister_trace_block_remap(blk_add_trace_remap
);
898 unregister_trace_block_split(blk_add_trace_split
);
899 unregister_trace_block_unplug_io(blk_add_trace_unplug_io
);
900 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
901 unregister_trace_block_plug(blk_add_trace_plug
);
902 unregister_trace_block_sleeprq(blk_add_trace_sleeprq
);
903 unregister_trace_block_getrq(blk_add_trace_getrq
);
904 unregister_trace_block_bio_queue(blk_add_trace_bio_queue
);
905 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
906 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
907 unregister_trace_block_bio_complete(blk_add_trace_bio_complete
);
908 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
909 unregister_trace_block_rq_complete(blk_add_trace_rq_complete
);
910 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
911 unregister_trace_block_rq_issue(blk_add_trace_rq_issue
);
912 unregister_trace_block_rq_insert(blk_add_trace_rq_insert
);
913 unregister_trace_block_rq_abort(blk_add_trace_rq_abort
);
915 tracepoint_synchronize_unregister();
919 * struct blk_io_tracer formatting routines
922 static void fill_rwbs(char *rwbs
, const struct blk_io_trace
*t
)
925 int tc
= t
->action
>> BLK_TC_SHIFT
;
927 if (tc
& BLK_TC_DISCARD
)
929 else if (tc
& BLK_TC_WRITE
)
936 if (tc
& BLK_TC_AHEAD
)
938 if (tc
& BLK_TC_BARRIER
)
940 if (tc
& BLK_TC_SYNC
)
942 if (tc
& BLK_TC_META
)
949 const struct blk_io_trace
*te_blk_io_trace(const struct trace_entry
*ent
)
951 return (const struct blk_io_trace
*)ent
;
954 static inline const void *pdu_start(const struct trace_entry
*ent
)
956 return te_blk_io_trace(ent
) + 1;
959 static inline u32
t_sec(const struct trace_entry
*ent
)
961 return te_blk_io_trace(ent
)->bytes
>> 9;
964 static inline unsigned long long t_sector(const struct trace_entry
*ent
)
966 return te_blk_io_trace(ent
)->sector
;
969 static inline __u16
t_error(const struct trace_entry
*ent
)
971 return te_blk_io_trace(ent
)->sector
;
974 static __u64
get_pdu_int(const struct trace_entry
*ent
)
976 const __u64
*val
= pdu_start(ent
);
977 return be64_to_cpu(*val
);
980 static void get_pdu_remap(const struct trace_entry
*ent
,
981 struct blk_io_trace_remap
*r
)
983 const struct blk_io_trace_remap
*__r
= pdu_start(ent
);
984 __u64 sector
= __r
->sector
;
986 r
->device
= be32_to_cpu(__r
->device
);
987 r
->device_from
= be32_to_cpu(__r
->device_from
);
988 r
->sector
= be64_to_cpu(sector
);
991 static int blk_log_action_iter(struct trace_iterator
*iter
, const char *act
)
994 unsigned long long ts
= ns2usecs(iter
->ts
);
995 unsigned long usec_rem
= do_div(ts
, USEC_PER_SEC
);
996 unsigned secs
= (unsigned long)ts
;
997 const struct trace_entry
*ent
= iter
->ent
;
998 const struct blk_io_trace
*t
= (const struct blk_io_trace
*)ent
;
1002 return trace_seq_printf(&iter
->seq
,
1003 "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
1004 MAJOR(t
->device
), MINOR(t
->device
), iter
->cpu
,
1005 secs
, usec_rem
, ent
->pid
, act
, rwbs
);
1008 static int blk_log_action_seq(struct trace_seq
*s
, const struct blk_io_trace
*t
,
1013 return trace_seq_printf(s
, "%3d,%-3d %2s %3s ",
1014 MAJOR(t
->device
), MINOR(t
->device
), act
, rwbs
);
1017 static int blk_log_generic(struct trace_seq
*s
, const struct trace_entry
*ent
)
1019 char cmd
[TASK_COMM_LEN
];
1021 trace_find_cmdline(ent
->pid
, cmd
);
1024 return trace_seq_printf(s
, "%llu + %u [%s]\n",
1025 t_sector(ent
), t_sec(ent
), cmd
);
1026 return trace_seq_printf(s
, "[%s]\n", cmd
);
1029 static int blk_log_with_error(struct trace_seq
*s
,
1030 const struct trace_entry
*ent
)
1033 return trace_seq_printf(s
, "%llu + %u [%d]\n", t_sector(ent
),
1034 t_sec(ent
), t_error(ent
));
1035 return trace_seq_printf(s
, "%llu [%d]\n", t_sector(ent
), t_error(ent
));
1038 static int blk_log_remap(struct trace_seq
*s
, const struct trace_entry
*ent
)
1040 struct blk_io_trace_remap r
= { .device
= 0, };
1042 get_pdu_remap(ent
, &r
);
1043 return trace_seq_printf(s
, "%llu + %u <- (%d,%d) %llu\n",
1045 t_sec(ent
), MAJOR(r
.device
), MINOR(r
.device
),
1046 (unsigned long long)r
.sector
);
1049 static int blk_log_plug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1051 char cmd
[TASK_COMM_LEN
];
1053 trace_find_cmdline(ent
->pid
, cmd
);
1055 return trace_seq_printf(s
, "[%s]\n", cmd
);
1058 static int blk_log_unplug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1060 char cmd
[TASK_COMM_LEN
];
1062 trace_find_cmdline(ent
->pid
, cmd
);
1064 return trace_seq_printf(s
, "[%s] %llu\n", cmd
, get_pdu_int(ent
));
1067 static int blk_log_split(struct trace_seq
*s
, const struct trace_entry
*ent
)
1069 char cmd
[TASK_COMM_LEN
];
1071 trace_find_cmdline(ent
->pid
, cmd
);
1073 return trace_seq_printf(s
, "%llu / %llu [%s]\n", t_sector(ent
),
1074 get_pdu_int(ent
), cmd
);
1078 * struct tracer operations
1081 static void blk_tracer_print_header(struct seq_file
*m
)
1083 if (!(blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
))
1085 seq_puts(m
, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1089 static void blk_tracer_start(struct trace_array
*tr
)
1091 if (atomic_add_return(1, &blk_probes_ref
) == 1)
1092 blk_register_tracepoints();
1093 trace_flags
&= ~TRACE_ITER_CONTEXT_INFO
;
1096 static int blk_tracer_init(struct trace_array
*tr
)
1099 blk_tracer_start(tr
);
1100 blk_tracer_enabled
= true;
1104 static void blk_tracer_stop(struct trace_array
*tr
)
1106 trace_flags
|= TRACE_ITER_CONTEXT_INFO
;
1107 if (atomic_dec_and_test(&blk_probes_ref
))
1108 blk_unregister_tracepoints();
1111 static void blk_tracer_reset(struct trace_array
*tr
)
1113 if (!atomic_read(&blk_probes_ref
))
1116 blk_tracer_enabled
= false;
1117 blk_tracer_stop(tr
);
1120 static const struct {
1122 int (*print
)(struct trace_seq
*s
, const struct trace_entry
*ent
);
1124 [__BLK_TA_QUEUE
] = {{ "Q", "queue" }, blk_log_generic
},
1125 [__BLK_TA_BACKMERGE
] = {{ "M", "backmerge" }, blk_log_generic
},
1126 [__BLK_TA_FRONTMERGE
] = {{ "F", "frontmerge" }, blk_log_generic
},
1127 [__BLK_TA_GETRQ
] = {{ "G", "getrq" }, blk_log_generic
},
1128 [__BLK_TA_SLEEPRQ
] = {{ "S", "sleeprq" }, blk_log_generic
},
1129 [__BLK_TA_REQUEUE
] = {{ "R", "requeue" }, blk_log_with_error
},
1130 [__BLK_TA_ISSUE
] = {{ "D", "issue" }, blk_log_generic
},
1131 [__BLK_TA_COMPLETE
] = {{ "C", "complete" }, blk_log_with_error
},
1132 [__BLK_TA_PLUG
] = {{ "P", "plug" }, blk_log_plug
},
1133 [__BLK_TA_UNPLUG_IO
] = {{ "U", "unplug_io" }, blk_log_unplug
},
1134 [__BLK_TA_UNPLUG_TIMER
] = {{ "UT", "unplug_timer" }, blk_log_unplug
},
1135 [__BLK_TA_INSERT
] = {{ "I", "insert" }, blk_log_generic
},
1136 [__BLK_TA_SPLIT
] = {{ "X", "split" }, blk_log_split
},
1137 [__BLK_TA_BOUNCE
] = {{ "B", "bounce" }, blk_log_generic
},
1138 [__BLK_TA_REMAP
] = {{ "A", "remap" }, blk_log_remap
},
1141 static enum print_line_t
blk_trace_event_print(struct trace_iterator
*iter
,
1144 struct trace_seq
*s
= &iter
->seq
;
1145 const struct blk_io_trace
*t
= (struct blk_io_trace
*)iter
->ent
;
1146 const u16 what
= t
->action
& ((1 << BLK_TC_SHIFT
) - 1);
1149 if (!trace_print_context(iter
))
1150 return TRACE_TYPE_PARTIAL_LINE
;
1152 if (unlikely(what
== 0 || what
> ARRAY_SIZE(what2act
)))
1153 ret
= trace_seq_printf(s
, "Bad pc action %x\n", what
);
1155 const bool long_act
= !!(trace_flags
& TRACE_ITER_VERBOSE
);
1156 ret
= blk_log_action_seq(s
, t
, what2act
[what
].act
[long_act
]);
1158 ret
= what2act
[what
].print(s
, iter
->ent
);
1161 return ret
? TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1164 static int blk_trace_synthesize_old_trace(struct trace_iterator
*iter
)
1166 struct trace_seq
*s
= &iter
->seq
;
1167 struct blk_io_trace
*t
= (struct blk_io_trace
*)iter
->ent
;
1168 const int offset
= offsetof(struct blk_io_trace
, sector
);
1169 struct blk_io_trace old
= {
1170 .magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
,
1171 .time
= ns2usecs(iter
->ts
),
1174 if (!trace_seq_putmem(s
, &old
, offset
))
1176 return trace_seq_putmem(s
, &t
->sector
,
1177 sizeof(old
) - offset
+ t
->pdu_len
);
1180 static enum print_line_t
1181 blk_trace_event_print_binary(struct trace_iterator
*iter
, int flags
)
1183 return blk_trace_synthesize_old_trace(iter
) ?
1184 TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1187 static enum print_line_t
blk_tracer_print_line(struct trace_iterator
*iter
)
1189 const struct blk_io_trace
*t
;
1193 if (!(blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
))
1194 return TRACE_TYPE_UNHANDLED
;
1196 t
= (const struct blk_io_trace
*)iter
->ent
;
1197 what
= t
->action
& ((1 << BLK_TC_SHIFT
) - 1);
1199 if (unlikely(what
== 0 || what
> ARRAY_SIZE(what2act
)))
1200 ret
= trace_seq_printf(&iter
->seq
, "Bad pc action %x\n", what
);
1202 const bool long_act
= !!(trace_flags
& TRACE_ITER_VERBOSE
);
1203 ret
= blk_log_action_iter(iter
, what2act
[what
].act
[long_act
]);
1205 ret
= what2act
[what
].print(&iter
->seq
, iter
->ent
);
1208 return ret
? TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1211 static struct tracer blk_tracer __read_mostly
= {
1213 .init
= blk_tracer_init
,
1214 .reset
= blk_tracer_reset
,
1215 .start
= blk_tracer_start
,
1216 .stop
= blk_tracer_stop
,
1217 .print_header
= blk_tracer_print_header
,
1218 .print_line
= blk_tracer_print_line
,
1219 .flags
= &blk_tracer_flags
,
1222 static struct trace_event trace_blk_event
= {
1224 .trace
= blk_trace_event_print
,
1225 .binary
= blk_trace_event_print_binary
,
1228 static int __init
init_blk_tracer(void)
1230 if (!register_ftrace_event(&trace_blk_event
)) {
1231 pr_warning("Warning: could not register block events\n");
1235 if (register_tracer(&blk_tracer
) != 0) {
1236 pr_warning("Warning: could not register the block tracer\n");
1237 unregister_ftrace_event(&trace_blk_event
);
1244 device_initcall(init_blk_tracer
);
1246 static int blk_trace_remove_queue(struct request_queue
*q
)
1248 struct blk_trace
*bt
;
1250 bt
= xchg(&q
->blk_trace
, NULL
);
1259 * Setup everything required to start tracing
1261 static int blk_trace_setup_queue(struct request_queue
*q
, dev_t dev
)
1263 struct blk_trace
*old_bt
, *bt
= NULL
;
1265 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
1270 bt
->act_mask
= (u16
)-1;
1271 bt
->end_lba
= -1ULL;
1272 bt
->trace_state
= Blktrace_running
;
1274 old_bt
= xchg(&q
->blk_trace
, bt
);
1275 if (old_bt
!= NULL
) {
1276 (void)xchg(&q
->blk_trace
, old_bt
);
1285 * sysfs interface to enable and configure tracing
1288 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1289 struct device_attribute
*attr
,
1291 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1292 struct device_attribute
*attr
,
1293 const char *buf
, size_t count
);
1294 #define BLK_TRACE_DEVICE_ATTR(_name) \
1295 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1296 sysfs_blk_trace_attr_show, \
1297 sysfs_blk_trace_attr_store)
1299 static BLK_TRACE_DEVICE_ATTR(enable
);
1300 static BLK_TRACE_DEVICE_ATTR(act_mask
);
1301 static BLK_TRACE_DEVICE_ATTR(pid
);
1302 static BLK_TRACE_DEVICE_ATTR(start_lba
);
1303 static BLK_TRACE_DEVICE_ATTR(end_lba
);
1305 static struct attribute
*blk_trace_attrs
[] = {
1306 &dev_attr_enable
.attr
,
1307 &dev_attr_act_mask
.attr
,
1309 &dev_attr_start_lba
.attr
,
1310 &dev_attr_end_lba
.attr
,
1314 struct attribute_group blk_trace_attr_group
= {
1316 .attrs
= blk_trace_attrs
,
1319 static int blk_str2act_mask(const char *str
)
1322 char *copy
= kstrdup(str
, GFP_KERNEL
), *s
;
1330 char *sep
= strchr(s
, ',');
1335 if (strcasecmp(s
, "barrier") == 0)
1336 mask
|= BLK_TC_BARRIER
;
1337 else if (strcasecmp(s
, "complete") == 0)
1338 mask
|= BLK_TC_COMPLETE
;
1339 else if (strcasecmp(s
, "fs") == 0)
1341 else if (strcasecmp(s
, "issue") == 0)
1342 mask
|= BLK_TC_ISSUE
;
1343 else if (strcasecmp(s
, "pc") == 0)
1345 else if (strcasecmp(s
, "queue") == 0)
1346 mask
|= BLK_TC_QUEUE
;
1347 else if (strcasecmp(s
, "read") == 0)
1348 mask
|= BLK_TC_READ
;
1349 else if (strcasecmp(s
, "requeue") == 0)
1350 mask
|= BLK_TC_REQUEUE
;
1351 else if (strcasecmp(s
, "sync") == 0)
1352 mask
|= BLK_TC_SYNC
;
1353 else if (strcasecmp(s
, "write") == 0)
1354 mask
|= BLK_TC_WRITE
;
1366 static struct request_queue
*blk_trace_get_queue(struct block_device
*bdev
)
1368 if (bdev
->bd_disk
== NULL
)
1371 return bdev_get_queue(bdev
);
1374 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1375 struct device_attribute
*attr
,
1378 struct hd_struct
*p
= dev_to_part(dev
);
1379 struct request_queue
*q
;
1380 struct block_device
*bdev
;
1381 ssize_t ret
= -ENXIO
;
1384 bdev
= bdget(part_devt(p
));
1386 goto out_unlock_kernel
;
1388 q
= blk_trace_get_queue(bdev
);
1392 mutex_lock(&bdev
->bd_mutex
);
1394 if (attr
== &dev_attr_enable
) {
1395 ret
= sprintf(buf
, "%u\n", !!q
->blk_trace
);
1396 goto out_unlock_bdev
;
1399 if (q
->blk_trace
== NULL
)
1400 ret
= sprintf(buf
, "disabled\n");
1401 else if (attr
== &dev_attr_act_mask
)
1402 ret
= sprintf(buf
, "%#x\n", q
->blk_trace
->act_mask
);
1403 else if (attr
== &dev_attr_pid
)
1404 ret
= sprintf(buf
, "%u\n", q
->blk_trace
->pid
);
1405 else if (attr
== &dev_attr_start_lba
)
1406 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->start_lba
);
1407 else if (attr
== &dev_attr_end_lba
)
1408 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->end_lba
);
1411 mutex_unlock(&bdev
->bd_mutex
);
1419 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1420 struct device_attribute
*attr
,
1421 const char *buf
, size_t count
)
1423 struct block_device
*bdev
;
1424 struct request_queue
*q
;
1425 struct hd_struct
*p
;
1427 ssize_t ret
= -ENXIO
;
1432 if (attr
== &dev_attr_act_mask
) {
1433 if (sscanf(buf
, "%llx", &value
) != 1) {
1434 /* Assume it is a list of trace category names */
1435 value
= blk_str2act_mask(buf
);
1439 } else if (sscanf(buf
, "%llu", &value
) != 1)
1443 p
= dev_to_part(dev
);
1444 bdev
= bdget(part_devt(p
));
1446 goto out_unlock_kernel
;
1448 q
= blk_trace_get_queue(bdev
);
1452 mutex_lock(&bdev
->bd_mutex
);
1454 if (attr
== &dev_attr_enable
) {
1456 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1458 ret
= blk_trace_remove_queue(q
);
1459 goto out_unlock_bdev
;
1463 if (q
->blk_trace
== NULL
)
1464 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1467 if (attr
== &dev_attr_act_mask
)
1468 q
->blk_trace
->act_mask
= value
;
1469 else if (attr
== &dev_attr_pid
)
1470 q
->blk_trace
->pid
= value
;
1471 else if (attr
== &dev_attr_start_lba
)
1472 q
->blk_trace
->start_lba
= value
;
1473 else if (attr
== &dev_attr_end_lba
)
1474 q
->blk_trace
->end_lba
= value
;
1478 mutex_unlock(&bdev
->bd_mutex
);
1484 return ret
? ret
: count
;