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 <asm/uaccess.h>
28 #include <../kernel/trace/trace_output.h>
30 static unsigned int blktrace_seq __read_mostly
= 1;
32 static struct trace_array
*blk_tr
;
33 static int __read_mostly blk_tracer_enabled
;
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 DEFINE_MUTEX(blk_probe_mutex
);
51 static atomic_t blk_probes_ref
= ATOMIC_INIT(0);
53 static int blk_register_tracepoints(void);
54 static void blk_unregister_tracepoints(void);
57 * Send out a notify message.
59 static void trace_note(struct blk_trace
*bt
, pid_t pid
, int action
,
60 const void *data
, size_t len
)
62 struct blk_io_trace
*t
;
67 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + len
);
69 const int cpu
= smp_processor_id();
71 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
72 t
->time
= ktime_to_ns(ktime_get());
78 memcpy((void *) t
+ sizeof(*t
), data
, len
);
83 * Send out a notify for this process, if we haven't done so since a trace
86 static void trace_note_tsk(struct blk_trace
*bt
, struct task_struct
*tsk
)
88 tsk
->btrace_seq
= blktrace_seq
;
89 trace_note(bt
, tsk
->pid
, BLK_TN_PROCESS
, tsk
->comm
, sizeof(tsk
->comm
));
92 static void trace_note_time(struct blk_trace
*bt
)
99 words
[0] = now
.tv_sec
;
100 words
[1] = now
.tv_nsec
;
102 local_irq_save(flags
);
103 trace_note(bt
, 0, BLK_TN_TIMESTAMP
, words
, sizeof(words
));
104 local_irq_restore(flags
);
107 void __trace_note_message(struct blk_trace
*bt
, const char *fmt
, ...)
116 ftrace_vprintk(fmt
, args
);
124 local_irq_save(flags
);
125 buf
= per_cpu_ptr(bt
->msg_data
, smp_processor_id());
127 n
= vscnprintf(buf
, BLK_TN_MAX_MSG
, fmt
, args
);
130 trace_note(bt
, 0, BLK_TN_MESSAGE
, buf
, n
);
131 local_irq_restore(flags
);
133 EXPORT_SYMBOL_GPL(__trace_note_message
);
135 static int act_log_check(struct blk_trace
*bt
, u32 what
, sector_t sector
,
138 if (((bt
->act_mask
<< BLK_TC_SHIFT
) & what
) == 0)
140 if (sector
< bt
->start_lba
|| sector
> bt
->end_lba
)
142 if (bt
->pid
&& pid
!= bt
->pid
)
149 * Data direction bit lookup
151 static u32 ddir_act
[2] __read_mostly
= { BLK_TC_ACT(BLK_TC_READ
), 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
;
168 unsigned long *sequence
;
172 if (unlikely(bt
->trace_state
!= Blktrace_running
|| !blk_tracer_enabled
))
175 what
|= ddir_act
[rw
& WRITE
];
176 what
|= MASK_TC_BIT(rw
, BARRIER
);
177 what
|= MASK_TC_BIT(rw
, SYNC
);
178 what
|= MASK_TC_BIT(rw
, AHEAD
);
179 what
|= MASK_TC_BIT(rw
, META
);
180 what
|= MASK_TC_BIT(rw
, DISCARD
);
183 if (unlikely(act_log_check(bt
, what
, sector
, pid
)))
185 cpu
= raw_smp_processor_id();
188 struct trace_entry
*ent
;
189 tracing_record_cmdline(current
);
191 event
= ring_buffer_lock_reserve(blk_tr
->buffer
,
192 sizeof(*t
) + pdu_len
, &flags
);
196 ent
= ring_buffer_event_data(event
);
197 t
= (struct blk_io_trace
*)ent
;
198 pc
= preempt_count();
199 tracing_generic_entry_update(ent
, 0, pc
);
200 ent
->type
= TRACE_BLK
;
205 * A word about the locking here - we disable interrupts to reserve
206 * some space in the relay per-cpu buffer, to prevent an irq
207 * from coming in and stepping on our toes.
209 local_irq_save(flags
);
211 if (unlikely(tsk
->btrace_seq
!= blktrace_seq
))
212 trace_note_tsk(bt
, tsk
);
214 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + pdu_len
);
216 sequence
= per_cpu_ptr(bt
->sequence
, cpu
);
218 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
219 t
->sequence
= ++(*sequence
);
220 t
->time
= ktime_to_ns(ktime_get());
229 t
->pdu_len
= pdu_len
;
232 memcpy((void *) t
+ sizeof(*t
), pdu_data
, pdu_len
);
235 ring_buffer_unlock_commit(blk_tr
->buffer
, event
, flags
);
237 (blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
) == 0 &&
238 (trace_flags
& TRACE_ITER_STACKTRACE
) != 0)
239 __trace_stack(blk_tr
, NULL
, flags
, 5, pc
);
245 local_irq_restore(flags
);
248 static struct dentry
*blk_tree_root
;
249 static DEFINE_MUTEX(blk_tree_mutex
);
250 static unsigned int root_users
;
252 static inline void blk_remove_root(void)
255 debugfs_remove(blk_tree_root
);
256 blk_tree_root
= NULL
;
260 static void blk_remove_tree(struct dentry
*dir
)
262 mutex_lock(&blk_tree_mutex
);
264 if (--root_users
== 0)
266 mutex_unlock(&blk_tree_mutex
);
269 static struct dentry
*blk_create_tree(const char *blk_name
)
271 struct dentry
*dir
= NULL
;
274 mutex_lock(&blk_tree_mutex
);
276 if (!blk_tree_root
) {
277 blk_tree_root
= debugfs_create_dir("block", NULL
);
283 dir
= debugfs_create_dir(blk_name
, blk_tree_root
);
287 /* Delete root only if we created it */
293 mutex_unlock(&blk_tree_mutex
);
297 static void blk_trace_cleanup(struct blk_trace
*bt
)
299 relay_close(bt
->rchan
);
300 debugfs_remove(bt
->msg_file
);
301 debugfs_remove(bt
->dropped_file
);
302 blk_remove_tree(bt
->dir
);
303 free_percpu(bt
->sequence
);
304 free_percpu(bt
->msg_data
);
306 mutex_lock(&blk_probe_mutex
);
307 if (atomic_dec_and_test(&blk_probes_ref
))
308 blk_unregister_tracepoints();
309 mutex_unlock(&blk_probe_mutex
);
312 int blk_trace_remove(struct request_queue
*q
)
314 struct blk_trace
*bt
;
316 bt
= xchg(&q
->blk_trace
, NULL
);
320 if (bt
->trace_state
== Blktrace_setup
||
321 bt
->trace_state
== Blktrace_stopped
)
322 blk_trace_cleanup(bt
);
326 EXPORT_SYMBOL_GPL(blk_trace_remove
);
328 static int blk_dropped_open(struct inode
*inode
, struct file
*filp
)
330 filp
->private_data
= inode
->i_private
;
335 static ssize_t
blk_dropped_read(struct file
*filp
, char __user
*buffer
,
336 size_t count
, loff_t
*ppos
)
338 struct blk_trace
*bt
= filp
->private_data
;
341 snprintf(buf
, sizeof(buf
), "%u\n", atomic_read(&bt
->dropped
));
343 return simple_read_from_buffer(buffer
, count
, ppos
, buf
, strlen(buf
));
346 static const struct file_operations blk_dropped_fops
= {
347 .owner
= THIS_MODULE
,
348 .open
= blk_dropped_open
,
349 .read
= blk_dropped_read
,
352 static int blk_msg_open(struct inode
*inode
, struct file
*filp
)
354 filp
->private_data
= inode
->i_private
;
359 static ssize_t
blk_msg_write(struct file
*filp
, const char __user
*buffer
,
360 size_t count
, loff_t
*ppos
)
363 struct blk_trace
*bt
;
365 if (count
> BLK_TN_MAX_MSG
)
368 msg
= kmalloc(count
, GFP_KERNEL
);
372 if (copy_from_user(msg
, buffer
, count
)) {
377 bt
= filp
->private_data
;
378 __trace_note_message(bt
, "%s", msg
);
384 static const struct file_operations blk_msg_fops
= {
385 .owner
= THIS_MODULE
,
386 .open
= blk_msg_open
,
387 .write
= blk_msg_write
,
391 * Keep track of how many times we encountered a full subbuffer, to aid
392 * the user space app in telling how many lost events there were.
394 static int blk_subbuf_start_callback(struct rchan_buf
*buf
, void *subbuf
,
395 void *prev_subbuf
, size_t prev_padding
)
397 struct blk_trace
*bt
;
399 if (!relay_buf_full(buf
))
402 bt
= buf
->chan
->private_data
;
403 atomic_inc(&bt
->dropped
);
407 static int blk_remove_buf_file_callback(struct dentry
*dentry
)
409 debugfs_remove(dentry
);
413 static struct dentry
*blk_create_buf_file_callback(const char *filename
,
414 struct dentry
*parent
,
416 struct rchan_buf
*buf
,
419 return debugfs_create_file(filename
, mode
, parent
, buf
,
420 &relay_file_operations
);
423 static struct rchan_callbacks blk_relay_callbacks
= {
424 .subbuf_start
= blk_subbuf_start_callback
,
425 .create_buf_file
= blk_create_buf_file_callback
,
426 .remove_buf_file
= blk_remove_buf_file_callback
,
430 * Setup everything required to start tracing
432 int do_blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
433 struct blk_user_trace_setup
*buts
)
435 struct blk_trace
*old_bt
, *bt
= NULL
;
436 struct dentry
*dir
= NULL
;
439 if (!buts
->buf_size
|| !buts
->buf_nr
)
442 strncpy(buts
->name
, name
, BLKTRACE_BDEV_SIZE
);
443 buts
->name
[BLKTRACE_BDEV_SIZE
- 1] = '\0';
446 * some device names have larger paths - convert the slashes
447 * to underscores for this to work as expected
449 for (i
= 0; i
< strlen(buts
->name
); i
++)
450 if (buts
->name
[i
] == '/')
454 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
458 bt
->sequence
= alloc_percpu(unsigned long);
462 bt
->msg_data
= __alloc_percpu(BLK_TN_MAX_MSG
);
467 dir
= blk_create_tree(buts
->name
);
473 atomic_set(&bt
->dropped
, 0);
476 bt
->dropped_file
= debugfs_create_file("dropped", 0444, dir
, bt
, &blk_dropped_fops
);
477 if (!bt
->dropped_file
)
480 bt
->msg_file
= debugfs_create_file("msg", 0222, dir
, bt
, &blk_msg_fops
);
484 bt
->rchan
= relay_open("trace", dir
, buts
->buf_size
,
485 buts
->buf_nr
, &blk_relay_callbacks
, bt
);
489 bt
->act_mask
= buts
->act_mask
;
491 bt
->act_mask
= (u16
) -1;
493 bt
->start_lba
= buts
->start_lba
;
494 bt
->end_lba
= buts
->end_lba
;
499 bt
->trace_state
= Blktrace_setup
;
501 mutex_lock(&blk_probe_mutex
);
502 if (atomic_add_return(1, &blk_probes_ref
) == 1) {
503 ret
= blk_register_tracepoints();
507 mutex_unlock(&blk_probe_mutex
);
510 old_bt
= xchg(&q
->blk_trace
, bt
);
512 (void) xchg(&q
->blk_trace
, old_bt
);
518 atomic_dec(&blk_probes_ref
);
519 mutex_unlock(&blk_probe_mutex
);
522 blk_remove_tree(dir
);
525 debugfs_remove(bt
->msg_file
);
526 if (bt
->dropped_file
)
527 debugfs_remove(bt
->dropped_file
);
528 free_percpu(bt
->sequence
);
529 free_percpu(bt
->msg_data
);
531 relay_close(bt
->rchan
);
537 int blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
540 struct blk_user_trace_setup buts
;
543 ret
= copy_from_user(&buts
, arg
, sizeof(buts
));
547 ret
= do_blk_trace_setup(q
, name
, dev
, &buts
);
551 if (copy_to_user(arg
, &buts
, sizeof(buts
)))
556 EXPORT_SYMBOL_GPL(blk_trace_setup
);
558 int blk_trace_startstop(struct request_queue
*q
, int start
)
560 struct blk_trace
*bt
;
563 if ((bt
= q
->blk_trace
) == NULL
)
567 * For starting a trace, we can transition from a setup or stopped
568 * trace. For stopping a trace, the state must be running
572 if (bt
->trace_state
== Blktrace_setup
||
573 bt
->trace_state
== Blktrace_stopped
) {
576 bt
->trace_state
= Blktrace_running
;
582 if (bt
->trace_state
== Blktrace_running
) {
583 bt
->trace_state
= Blktrace_stopped
;
584 relay_flush(bt
->rchan
);
591 EXPORT_SYMBOL_GPL(blk_trace_startstop
);
594 * blk_trace_ioctl: - handle the ioctls associated with tracing
595 * @bdev: the block device
596 * @cmd: the ioctl cmd
597 * @arg: the argument data, if any
600 int blk_trace_ioctl(struct block_device
*bdev
, unsigned cmd
, char __user
*arg
)
602 struct request_queue
*q
;
604 char b
[BDEVNAME_SIZE
];
606 q
= bdev_get_queue(bdev
);
610 mutex_lock(&bdev
->bd_mutex
);
615 ret
= blk_trace_setup(q
, b
, bdev
->bd_dev
, arg
);
620 ret
= blk_trace_startstop(q
, start
);
622 case BLKTRACETEARDOWN
:
623 ret
= blk_trace_remove(q
);
630 mutex_unlock(&bdev
->bd_mutex
);
635 * blk_trace_shutdown: - stop and cleanup trace structures
636 * @q: the request queue associated with the device
639 void blk_trace_shutdown(struct request_queue
*q
)
642 blk_trace_startstop(q
, 0);
652 * blk_add_trace_rq - Add a trace for a request oriented action
653 * @q: queue the io is for
654 * @rq: the source request
658 * Records an action against a request. Will log the bio offset + size.
661 static void blk_add_trace_rq(struct request_queue
*q
, struct request
*rq
,
664 struct blk_trace
*bt
= q
->blk_trace
;
665 int rw
= rq
->cmd_flags
& 0x03;
670 if (blk_discard_rq(rq
))
671 rw
|= (1 << BIO_RW_DISCARD
);
673 if (blk_pc_request(rq
)) {
674 what
|= BLK_TC_ACT(BLK_TC_PC
);
675 __blk_add_trace(bt
, 0, rq
->data_len
, rw
, what
, rq
->errors
,
676 sizeof(rq
->cmd
), rq
->cmd
);
678 what
|= BLK_TC_ACT(BLK_TC_FS
);
679 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
680 rw
, what
, rq
->errors
, 0, NULL
);
684 static void blk_add_trace_rq_abort(struct request_queue
*q
, struct request
*rq
)
686 blk_add_trace_rq(q
, rq
, BLK_TA_ABORT
);
689 static void blk_add_trace_rq_insert(struct request_queue
*q
, struct request
*rq
)
691 blk_add_trace_rq(q
, rq
, BLK_TA_INSERT
);
694 static void blk_add_trace_rq_issue(struct request_queue
*q
, struct request
*rq
)
696 blk_add_trace_rq(q
, rq
, BLK_TA_ISSUE
);
699 static void blk_add_trace_rq_requeue(struct request_queue
*q
, struct request
*rq
)
701 blk_add_trace_rq(q
, rq
, BLK_TA_REQUEUE
);
704 static void blk_add_trace_rq_complete(struct request_queue
*q
, struct request
*rq
)
706 blk_add_trace_rq(q
, rq
, BLK_TA_COMPLETE
);
710 * blk_add_trace_bio - Add a trace for a bio oriented action
711 * @q: queue the io is for
712 * @bio: the source bio
716 * Records an action against a bio. Will log the bio offset + size.
719 static void blk_add_trace_bio(struct request_queue
*q
, struct bio
*bio
,
722 struct blk_trace
*bt
= q
->blk_trace
;
727 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
, what
,
728 !bio_flagged(bio
, BIO_UPTODATE
), 0, NULL
);
731 static void blk_add_trace_bio_bounce(struct request_queue
*q
, struct bio
*bio
)
733 blk_add_trace_bio(q
, bio
, BLK_TA_BOUNCE
);
736 static void blk_add_trace_bio_complete(struct request_queue
*q
, struct bio
*bio
)
738 blk_add_trace_bio(q
, bio
, BLK_TA_COMPLETE
);
741 static void blk_add_trace_bio_backmerge(struct request_queue
*q
, struct bio
*bio
)
743 blk_add_trace_bio(q
, bio
, BLK_TA_BACKMERGE
);
746 static void blk_add_trace_bio_frontmerge(struct request_queue
*q
, struct bio
*bio
)
748 blk_add_trace_bio(q
, bio
, BLK_TA_FRONTMERGE
);
751 static void blk_add_trace_bio_queue(struct request_queue
*q
, struct bio
*bio
)
753 blk_add_trace_bio(q
, bio
, BLK_TA_QUEUE
);
756 static void blk_add_trace_getrq(struct request_queue
*q
, struct bio
*bio
, int rw
)
759 blk_add_trace_bio(q
, bio
, BLK_TA_GETRQ
);
761 struct blk_trace
*bt
= q
->blk_trace
;
764 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_GETRQ
, 0, 0, NULL
);
769 static void blk_add_trace_sleeprq(struct request_queue
*q
, struct bio
*bio
, int rw
)
772 blk_add_trace_bio(q
, bio
, BLK_TA_SLEEPRQ
);
774 struct blk_trace
*bt
= q
->blk_trace
;
777 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_SLEEPRQ
, 0, 0, NULL
);
781 static void blk_add_trace_plug(struct request_queue
*q
)
783 struct blk_trace
*bt
= q
->blk_trace
;
786 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_PLUG
, 0, 0, NULL
);
789 static void blk_add_trace_unplug_io(struct request_queue
*q
)
791 struct blk_trace
*bt
= q
->blk_trace
;
794 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
795 __be64 rpdu
= cpu_to_be64(pdu
);
797 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_IO
, 0,
798 sizeof(rpdu
), &rpdu
);
802 static void blk_add_trace_unplug_timer(struct request_queue
*q
)
804 struct blk_trace
*bt
= q
->blk_trace
;
807 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
808 __be64 rpdu
= cpu_to_be64(pdu
);
810 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_TIMER
, 0,
811 sizeof(rpdu
), &rpdu
);
815 static void blk_add_trace_split(struct request_queue
*q
, struct bio
*bio
,
818 struct blk_trace
*bt
= q
->blk_trace
;
821 __be64 rpdu
= cpu_to_be64(pdu
);
823 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
,
824 BLK_TA_SPLIT
, !bio_flagged(bio
, BIO_UPTODATE
),
825 sizeof(rpdu
), &rpdu
);
830 * blk_add_trace_remap - Add a trace for a remap operation
831 * @q: queue the io is for
832 * @bio: the source bio
833 * @dev: target device
834 * @from: source sector
838 * Device mapper or raid target sometimes need to split a bio because
839 * it spans a stripe (or similar). Add a trace for that action.
842 static void blk_add_trace_remap(struct request_queue
*q
, struct bio
*bio
,
843 dev_t dev
, sector_t from
, sector_t to
)
845 struct blk_trace
*bt
= q
->blk_trace
;
846 struct blk_io_trace_remap r
;
851 r
.device
= cpu_to_be32(dev
);
852 r
.device_from
= cpu_to_be32(bio
->bi_bdev
->bd_dev
);
853 r
.sector
= cpu_to_be64(to
);
855 __blk_add_trace(bt
, from
, bio
->bi_size
, bio
->bi_rw
, BLK_TA_REMAP
,
856 !bio_flagged(bio
, BIO_UPTODATE
), sizeof(r
), &r
);
860 * blk_add_driver_data - Add binary message with driver-specific data
861 * @q: queue the io is for
863 * @data: driver-specific data
864 * @len: length of driver-specific data
867 * Some drivers might want to write driver-specific data per request.
870 void blk_add_driver_data(struct request_queue
*q
,
872 void *data
, size_t len
)
874 struct blk_trace
*bt
= q
->blk_trace
;
879 if (blk_pc_request(rq
))
880 __blk_add_trace(bt
, 0, rq
->data_len
, 0, BLK_TA_DRV_DATA
,
881 rq
->errors
, len
, data
);
883 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
884 0, BLK_TA_DRV_DATA
, rq
->errors
, len
, data
);
886 EXPORT_SYMBOL_GPL(blk_add_driver_data
);
888 static int blk_register_tracepoints(void)
892 ret
= register_trace_block_rq_abort(blk_add_trace_rq_abort
);
894 ret
= register_trace_block_rq_insert(blk_add_trace_rq_insert
);
896 ret
= register_trace_block_rq_issue(blk_add_trace_rq_issue
);
898 ret
= register_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
900 ret
= register_trace_block_rq_complete(blk_add_trace_rq_complete
);
902 ret
= register_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
904 ret
= register_trace_block_bio_complete(blk_add_trace_bio_complete
);
906 ret
= register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
908 ret
= register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
910 ret
= register_trace_block_bio_queue(blk_add_trace_bio_queue
);
912 ret
= register_trace_block_getrq(blk_add_trace_getrq
);
914 ret
= register_trace_block_sleeprq(blk_add_trace_sleeprq
);
916 ret
= register_trace_block_plug(blk_add_trace_plug
);
918 ret
= register_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
920 ret
= register_trace_block_unplug_io(blk_add_trace_unplug_io
);
922 ret
= register_trace_block_split(blk_add_trace_split
);
924 ret
= register_trace_block_remap(blk_add_trace_remap
);
929 static void blk_unregister_tracepoints(void)
931 unregister_trace_block_remap(blk_add_trace_remap
);
932 unregister_trace_block_split(blk_add_trace_split
);
933 unregister_trace_block_unplug_io(blk_add_trace_unplug_io
);
934 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
935 unregister_trace_block_plug(blk_add_trace_plug
);
936 unregister_trace_block_sleeprq(blk_add_trace_sleeprq
);
937 unregister_trace_block_getrq(blk_add_trace_getrq
);
938 unregister_trace_block_bio_queue(blk_add_trace_bio_queue
);
939 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
940 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
941 unregister_trace_block_bio_complete(blk_add_trace_bio_complete
);
942 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
943 unregister_trace_block_rq_complete(blk_add_trace_rq_complete
);
944 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
945 unregister_trace_block_rq_issue(blk_add_trace_rq_issue
);
946 unregister_trace_block_rq_insert(blk_add_trace_rq_insert
);
947 unregister_trace_block_rq_abort(blk_add_trace_rq_abort
);
949 tracepoint_synchronize_unregister();
953 * struct blk_io_tracer formatting routines
956 static void fill_rwbs(char *rwbs
, const struct blk_io_trace
*t
)
960 if (t
->action
& BLK_TC_DISCARD
) rwbs
[i
++] = 'D';
961 else if (t
->action
& BLK_TC_WRITE
) rwbs
[i
++] = 'W';
962 else if (t
->bytes
) rwbs
[i
++] = 'R';
963 else rwbs
[i
++] = 'N';
965 if (t
->action
& BLK_TC_AHEAD
) rwbs
[i
++] = 'A';
966 if (t
->action
& BLK_TC_BARRIER
) rwbs
[i
++] = 'B';
967 if (t
->action
& BLK_TC_SYNC
) rwbs
[i
++] = 'S';
968 if (t
->action
& BLK_TC_META
) rwbs
[i
++] = 'M';
974 const struct blk_io_trace
*te_blk_io_trace(const struct trace_entry
*ent
)
976 return (const struct blk_io_trace
*)ent
;
979 static inline const void *pdu_start(const struct trace_entry
*ent
)
981 return te_blk_io_trace(ent
) + 1;
984 static inline u32
t_sec(const struct trace_entry
*ent
)
986 return te_blk_io_trace(ent
)->bytes
>> 9;
989 static inline unsigned long long t_sector(const struct trace_entry
*ent
)
991 return te_blk_io_trace(ent
)->sector
;
994 static inline __u16
t_error(const struct trace_entry
*ent
)
996 return te_blk_io_trace(ent
)->sector
;
999 static __u64
get_pdu_int(const struct trace_entry
*ent
)
1001 const __u64
*val
= pdu_start(ent
);
1002 return be64_to_cpu(*val
);
1005 static void get_pdu_remap(const struct trace_entry
*ent
,
1006 struct blk_io_trace_remap
*r
)
1008 const struct blk_io_trace_remap
*__r
= pdu_start(ent
);
1009 __u64 sector
= __r
->sector
;
1011 r
->device
= be32_to_cpu(__r
->device
);
1012 r
->device_from
= be32_to_cpu(__r
->device_from
);
1013 r
->sector
= be64_to_cpu(sector
);
1016 static int blk_log_action_iter(struct trace_iterator
*iter
, const char *act
)
1019 unsigned long long ts
= ns2usecs(iter
->ts
);
1020 unsigned long usec_rem
= do_div(ts
, USEC_PER_SEC
);
1021 unsigned secs
= (unsigned long)ts
;
1022 const struct trace_entry
*ent
= iter
->ent
;
1023 const struct blk_io_trace
*t
= (const struct blk_io_trace
*)ent
;
1027 return trace_seq_printf(&iter
->seq
,
1028 "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
1029 MAJOR(t
->device
), MINOR(t
->device
), iter
->cpu
,
1030 secs
, usec_rem
, ent
->pid
, act
, rwbs
);
1033 static int blk_log_action_seq(struct trace_seq
*s
, const struct blk_io_trace
*t
,
1038 return trace_seq_printf(s
, "%3d,%-3d %2s %3s ",
1039 MAJOR(t
->device
), MINOR(t
->device
), act
, rwbs
);
1042 static int blk_log_generic(struct trace_seq
*s
, const struct trace_entry
*ent
)
1044 const char *cmd
= trace_find_cmdline(ent
->pid
);
1047 return trace_seq_printf(s
, "%llu + %u [%s]\n",
1048 t_sector(ent
), t_sec(ent
), cmd
);
1049 return trace_seq_printf(s
, "[%s]\n", cmd
);
1052 static int blk_log_with_error(struct trace_seq
*s
, const struct trace_entry
*ent
)
1055 return trace_seq_printf(s
, "%llu + %u [%d]\n", t_sector(ent
),
1056 t_sec(ent
), t_error(ent
));
1057 return trace_seq_printf(s
, "%llu [%d]\n", t_sector(ent
), t_error(ent
));
1060 static int blk_log_remap(struct trace_seq
*s
, const struct trace_entry
*ent
)
1062 struct blk_io_trace_remap r
= { .device
= 0, };
1064 get_pdu_remap(ent
, &r
);
1065 return trace_seq_printf(s
, "%llu + %u <- (%d,%d) %llu\n",
1067 t_sec(ent
), MAJOR(r
.device
), MINOR(r
.device
),
1068 (unsigned long long)r
.sector
);
1071 static int blk_log_plug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1073 return trace_seq_printf(s
, "[%s]\n", trace_find_cmdline(ent
->pid
));
1076 static int blk_log_unplug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1078 return trace_seq_printf(s
, "[%s] %llu\n", trace_find_cmdline(ent
->pid
),
1082 static int blk_log_split(struct trace_seq
*s
, const struct trace_entry
*ent
)
1084 return trace_seq_printf(s
, "%llu / %llu [%s]\n", t_sector(ent
),
1085 get_pdu_int(ent
), trace_find_cmdline(ent
->pid
));
1089 * struct tracer operations
1092 static void blk_tracer_print_header(struct seq_file
*m
)
1094 if (!(blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
))
1096 seq_puts(m
, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1100 static void blk_tracer_start(struct trace_array
*tr
)
1104 tr
->time_start
= ftrace_now(tr
->cpu
);
1106 for_each_online_cpu(cpu
)
1107 tracing_reset(tr
, cpu
);
1109 mutex_lock(&blk_probe_mutex
);
1110 if (atomic_add_return(1, &blk_probes_ref
) == 1)
1111 if (blk_register_tracepoints())
1112 atomic_dec(&blk_probes_ref
);
1113 mutex_unlock(&blk_probe_mutex
);
1116 static int blk_tracer_init(struct trace_array
*tr
)
1119 blk_tracer_start(tr
);
1120 mutex_lock(&blk_probe_mutex
);
1121 blk_tracer_enabled
++;
1122 mutex_unlock(&blk_probe_mutex
);
1126 static void blk_tracer_stop(struct trace_array
*tr
)
1128 mutex_lock(&blk_probe_mutex
);
1129 if (atomic_dec_and_test(&blk_probes_ref
))
1130 blk_unregister_tracepoints();
1131 mutex_unlock(&blk_probe_mutex
);
1134 static void blk_tracer_reset(struct trace_array
*tr
)
1136 if (!atomic_read(&blk_probes_ref
))
1139 mutex_lock(&blk_probe_mutex
);
1140 blk_tracer_enabled
--;
1141 WARN_ON(blk_tracer_enabled
< 0);
1142 mutex_unlock(&blk_probe_mutex
);
1144 blk_tracer_stop(tr
);
1149 int (*print
)(struct trace_seq
*s
, const struct trace_entry
*ent
);
1150 } what2act
[] __read_mostly
= {
1151 [__BLK_TA_QUEUE
] = {{ "Q", "queue" }, blk_log_generic
},
1152 [__BLK_TA_BACKMERGE
] = {{ "M", "backmerge" }, blk_log_generic
},
1153 [__BLK_TA_FRONTMERGE
] = {{ "F", "frontmerge" }, blk_log_generic
},
1154 [__BLK_TA_GETRQ
] = {{ "G", "getrq" }, blk_log_generic
},
1155 [__BLK_TA_SLEEPRQ
] = {{ "S", "sleeprq" }, blk_log_generic
},
1156 [__BLK_TA_REQUEUE
] = {{ "R", "requeue" }, blk_log_with_error
},
1157 [__BLK_TA_ISSUE
] = {{ "D", "issue" }, blk_log_generic
},
1158 [__BLK_TA_COMPLETE
] = {{ "C", "complete" }, blk_log_with_error
},
1159 [__BLK_TA_PLUG
] = {{ "P", "plug" }, blk_log_plug
},
1160 [__BLK_TA_UNPLUG_IO
] = {{ "U", "unplug_io" }, blk_log_unplug
},
1161 [__BLK_TA_UNPLUG_TIMER
] = {{ "UT", "unplug_timer" }, blk_log_unplug
},
1162 [__BLK_TA_INSERT
] = {{ "I", "insert" }, blk_log_generic
},
1163 [__BLK_TA_SPLIT
] = {{ "X", "split" }, blk_log_split
},
1164 [__BLK_TA_BOUNCE
] = {{ "B", "bounce" }, blk_log_generic
},
1165 [__BLK_TA_REMAP
] = {{ "A", "remap" }, blk_log_remap
},
1168 static int blk_trace_event_print(struct trace_seq
*s
, struct trace_entry
*ent
,
1171 const struct blk_io_trace
*t
= (struct blk_io_trace
*)ent
;
1172 const u16 what
= t
->action
& ((1 << BLK_TC_SHIFT
) - 1);
1175 if (unlikely(what
== 0 || what
> ARRAY_SIZE(what2act
)))
1176 ret
= trace_seq_printf(s
, "Bad pc action %x\n", what
);
1178 const bool long_act
= !!(trace_flags
& TRACE_ITER_VERBOSE
);
1179 ret
= blk_log_action_seq(s
, t
, what2act
[what
].act
[long_act
]);
1181 ret
= what2act
[what
].print(s
, ent
);
1184 return ret
? 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 .latency_trace
= blk_trace_event_print
,
1226 .raw
= trace_nop_print
,
1227 .hex
= trace_nop_print
,
1228 .binary
= trace_nop_print
,
1231 static int __init
init_blk_tracer(void)
1233 if (!register_ftrace_event(&trace_blk_event
)) {
1234 pr_warning("Warning: could not register block events\n");
1238 if (register_tracer(&blk_tracer
) != 0) {
1239 pr_warning("Warning: could not register the block tracer\n");
1240 unregister_ftrace_event(&trace_blk_event
);
1247 device_initcall(init_blk_tracer
);
1249 static int blk_trace_remove_queue(struct request_queue
*q
)
1251 struct blk_trace
*bt
;
1253 bt
= xchg(&q
->blk_trace
, NULL
);
1262 * Setup everything required to start tracing
1264 static int blk_trace_setup_queue(struct request_queue
*q
, dev_t dev
)
1266 struct blk_trace
*old_bt
, *bt
= NULL
;
1270 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
1275 bt
->act_mask
= (u16
)-1;
1276 bt
->end_lba
= -1ULL;
1277 bt
->trace_state
= Blktrace_running
;
1279 old_bt
= xchg(&q
->blk_trace
, bt
);
1280 if (old_bt
!= NULL
) {
1281 (void)xchg(&q
->blk_trace
, old_bt
);
1291 * sysfs interface to enable and configure tracing
1294 static ssize_t
sysfs_blk_trace_enable_show(struct device
*dev
,
1295 struct device_attribute
*attr
,
1298 struct hd_struct
*p
= dev_to_part(dev
);
1299 struct block_device
*bdev
;
1300 ssize_t ret
= -ENXIO
;
1303 bdev
= bdget(part_devt(p
));
1305 struct request_queue
*q
= bdev_get_queue(bdev
);
1308 mutex_lock(&bdev
->bd_mutex
);
1309 ret
= sprintf(buf
, "%u\n", !!q
->blk_trace
);
1310 mutex_unlock(&bdev
->bd_mutex
);
1320 static ssize_t
sysfs_blk_trace_enable_store(struct device
*dev
,
1321 struct device_attribute
*attr
,
1322 const char *buf
, size_t count
)
1324 struct block_device
*bdev
;
1325 struct request_queue
*q
;
1326 struct hd_struct
*p
;
1328 ssize_t ret
= -ENXIO
;
1330 if (count
== 0 || sscanf(buf
, "%d", &value
) != 1)
1334 p
= dev_to_part(dev
);
1335 bdev
= bdget(part_devt(p
));
1337 goto out_unlock_kernel
;
1339 q
= bdev_get_queue(bdev
);
1343 mutex_lock(&bdev
->bd_mutex
);
1345 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1347 ret
= blk_trace_remove_queue(q
);
1348 mutex_unlock(&bdev
->bd_mutex
);
1360 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1361 struct device_attribute
*attr
,
1363 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1364 struct device_attribute
*attr
,
1365 const char *buf
, size_t count
);
1366 #define BLK_TRACE_DEVICE_ATTR(_name) \
1367 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1368 sysfs_blk_trace_attr_show, \
1369 sysfs_blk_trace_attr_store)
1371 static DEVICE_ATTR(enable
, S_IRUGO
| S_IWUSR
,
1372 sysfs_blk_trace_enable_show
, sysfs_blk_trace_enable_store
);
1373 static BLK_TRACE_DEVICE_ATTR(act_mask
);
1374 static BLK_TRACE_DEVICE_ATTR(pid
);
1375 static BLK_TRACE_DEVICE_ATTR(start_lba
);
1376 static BLK_TRACE_DEVICE_ATTR(end_lba
);
1378 static struct attribute
*blk_trace_attrs
[] = {
1379 &dev_attr_enable
.attr
,
1380 &dev_attr_act_mask
.attr
,
1382 &dev_attr_start_lba
.attr
,
1383 &dev_attr_end_lba
.attr
,
1387 struct attribute_group blk_trace_attr_group
= {
1389 .attrs
= blk_trace_attrs
,
1392 static int blk_str2act_mask(const char *str
)
1395 char *copy
= kstrdup(str
, GFP_KERNEL
), *s
;
1403 char *sep
= strchr(s
, ',');
1408 if (strcasecmp(s
, "barrier") == 0)
1409 mask
|= BLK_TC_BARRIER
;
1410 else if (strcasecmp(s
, "complete") == 0)
1411 mask
|= BLK_TC_COMPLETE
;
1412 else if (strcasecmp(s
, "fs") == 0)
1414 else if (strcasecmp(s
, "issue") == 0)
1415 mask
|= BLK_TC_ISSUE
;
1416 else if (strcasecmp(s
, "pc") == 0)
1418 else if (strcasecmp(s
, "queue") == 0)
1419 mask
|= BLK_TC_QUEUE
;
1420 else if (strcasecmp(s
, "read") == 0)
1421 mask
|= BLK_TC_READ
;
1422 else if (strcasecmp(s
, "requeue") == 0)
1423 mask
|= BLK_TC_REQUEUE
;
1424 else if (strcasecmp(s
, "sync") == 0)
1425 mask
|= BLK_TC_SYNC
;
1426 else if (strcasecmp(s
, "write") == 0)
1427 mask
|= BLK_TC_WRITE
;
1439 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1440 struct device_attribute
*attr
,
1443 struct hd_struct
*p
= dev_to_part(dev
);
1444 struct request_queue
*q
;
1445 struct block_device
*bdev
;
1446 ssize_t ret
= -ENXIO
;
1449 bdev
= bdget(part_devt(p
));
1451 goto out_unlock_kernel
;
1453 q
= bdev_get_queue(bdev
);
1456 mutex_lock(&bdev
->bd_mutex
);
1457 if (q
->blk_trace
== NULL
)
1458 ret
= sprintf(buf
, "disabled\n");
1459 else if (attr
== &dev_attr_act_mask
)
1460 ret
= sprintf(buf
, "%#x\n", q
->blk_trace
->act_mask
);
1461 else if (attr
== &dev_attr_pid
)
1462 ret
= sprintf(buf
, "%u\n", q
->blk_trace
->pid
);
1463 else if (attr
== &dev_attr_start_lba
)
1464 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->start_lba
);
1465 else if (attr
== &dev_attr_end_lba
)
1466 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->end_lba
);
1467 mutex_unlock(&bdev
->bd_mutex
);
1475 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1476 struct device_attribute
*attr
,
1477 const char *buf
, size_t count
)
1479 struct block_device
*bdev
;
1480 struct request_queue
*q
;
1481 struct hd_struct
*p
;
1483 ssize_t ret
= -ENXIO
;
1488 if (attr
== &dev_attr_act_mask
) {
1489 if (sscanf(buf
, "%llx", &value
) != 1) {
1490 /* Assume it is a list of trace category names */
1491 value
= blk_str2act_mask(buf
);
1495 } else if (sscanf(buf
, "%llu", &value
) != 1)
1499 p
= dev_to_part(dev
);
1500 bdev
= bdget(part_devt(p
));
1502 goto out_unlock_kernel
;
1504 q
= bdev_get_queue(bdev
);
1508 mutex_lock(&bdev
->bd_mutex
);
1510 if (q
->blk_trace
== NULL
)
1511 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1514 if (attr
== &dev_attr_act_mask
)
1515 q
->blk_trace
->act_mask
= value
;
1516 else if (attr
== &dev_attr_pid
)
1517 q
->blk_trace
->pid
= value
;
1518 else if (attr
== &dev_attr_start_lba
)
1519 q
->blk_trace
->start_lba
= value
;
1520 else if (attr
== &dev_attr_end_lba
)
1521 q
->blk_trace
->end_lba
= value
;
1524 mutex_unlock(&bdev
->bd_mutex
);