tracing/blktrace: move the tracing file to kernel/trace

Impact: cleanup

Move blktrace.c to kernel/trace, also move its config entry.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 0 insertions, 1563 deletions

diff --git a/block/Kconfig b/block/Kconfig
index 7cdaa1d72252..e7d12782bcfb 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -44,30 +44,6 @@ config LBD
 
 	  If unsure, say N.
 
-config BLK_DEV_IO_TRACE
-	bool "Support for tracing block io actions"
-	depends on SYSFS
-	select RELAY
-	select DEBUG_FS
-	select TRACEPOINTS
-	select TRACING
-	select STACKTRACE
-	help
-	  Say Y here if you want to be able to trace the block layer actions
-	  on a given queue. Tracing allows you to see any traffic happening
-	  on a block device queue. For more information (and the userspace
-	  support tools needed), fetch the blktrace tools from:
-
-	  git://git.kernel.dk/blktrace.git
-
-	  Tracing also is possible using the ftrace interface, e.g.:
-
-	    echo 1 > /sys/block/sda/sda1/trace/enable
-	    echo blk > /sys/kernel/debug/tracing/current_tracer
-	    cat /sys/kernel/debug/tracing/trace_pipe
-
-	  If unsure, say N.
-
 config BLK_DEV_BSG
 	bool "Block layer SG support v4 (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
diff --git a/block/Makefile b/block/Makefile
index bfe73049f939..e9fa4dd690f2 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -13,6 +13,5 @@ obj-$(CONFIG_IOSCHED_AS)	+= as-iosched.o
 obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
 
-obj-$(CONFIG_BLK_DEV_IO_TRACE)	+= blktrace.o
 obj-$(CONFIG_BLOCK_COMPAT)	+= compat_ioctl.o
 obj-$(CONFIG_BLK_DEV_INTEGRITY)	+= blk-integrity.o
diff --git a/block/blktrace.c b/block/blktrace.c
deleted file mode 100644
index ca6d32061e4f..000000000000
--- a/block/blktrace.c
+++ /dev/null
@@ -1,1538 +0,0 @@
-/*
- * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- */
-#include <linux/kernel.h>
-#include <linux/blkdev.h>
-#include <linux/blktrace_api.h>
-#include <linux/percpu.h>
-#include <linux/init.h>
-#include <linux/mutex.h>
-#include <linux/debugfs.h>
-#include <linux/time.h>
-#include <trace/block.h>
-#include <linux/uaccess.h>
-#include <../kernel/trace/trace_output.h>
-
-static unsigned int blktrace_seq __read_mostly = 1;
-
-static struct trace_array *blk_tr;
-static int __read_mostly  blk_tracer_enabled;
-
-/* Select an alternative, minimalistic output than the original one */
-#define TRACE_BLK_OPT_CLASSIC 	0x1
-
-static struct tracer_opt blk_tracer_opts[] = {
-	/* Default disable the minimalistic output */
-	{ TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
-	{ }
-};
-
-static struct tracer_flags blk_tracer_flags = {
-	.val  = 0,
-	.opts = blk_tracer_opts,
-};
-
-/* Global reference count of probes */
-static DEFINE_MUTEX(blk_probe_mutex);
-static atomic_t blk_probes_ref = ATOMIC_INIT(0);
-
-static int blk_register_tracepoints(void);
-static void blk_unregister_tracepoints(void);
-
-/*
- * Send out a notify message.
- */
-static void trace_note(struct blk_trace *bt, pid_t pid, int action,
-		       const void *data, size_t len)
-{
-	struct blk_io_trace *t;
-
-	if (!bt->rchan)
-		return;
-
-	t = relay_reserve(bt->rchan, sizeof(*t) + len);
-	if (t) {
-		const int cpu = smp_processor_id();
-
-		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
-		t->time = ktime_to_ns(ktime_get());
-		t->device = bt->dev;
-		t->action = action;
-		t->pid = pid;
-		t->cpu = cpu;
-		t->pdu_len = len;
-		memcpy((void *) t + sizeof(*t), data, len);
-	}
-}
-
-/*
- * Send out a notify for this process, if we haven't done so since a trace
- * started
- */
-static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
-{
-	tsk->btrace_seq = blktrace_seq;
-	trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
-}
-
-static void trace_note_time(struct blk_trace *bt)
-{
-	struct timespec now;
-	unsigned long flags;
-	u32 words[2];
-
-	getnstimeofday(&now);
-	words[0] = now.tv_sec;
-	words[1] = now.tv_nsec;
-
-	local_irq_save(flags);
-	trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
-	local_irq_restore(flags);
-}
-
-void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
-{
-	int n;
-	va_list args;
-	unsigned long flags;
-	char *buf;
-
-	if (blk_tr) {
-		va_start(args, fmt);
-		ftrace_vprintk(fmt, args);
-		va_end(args);
-		return;
-	}
-
-	if (!bt->msg_data)
-		return;
-
-	local_irq_save(flags);
-	buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
-	va_start(args, fmt);
-	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
-	va_end(args);
-
-	trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(__trace_note_message);
-
-static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
-			 pid_t pid)
-{
-	if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
-		return 1;
-	if (sector < bt->start_lba || sector > bt->end_lba)
-		return 1;
-	if (bt->pid && pid != bt->pid)
-		return 1;
-
-	return 0;
-}
-
-/*
- * Data direction bit lookup
- */
-static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ),
-					 BLK_TC_ACT(BLK_TC_WRITE) };
-
-/* The ilog2() calls fall out because they're constant */
-#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
-	  (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
-
-/*
- * The worker for the various blk_add_trace*() types. Fills out a
- * blk_io_trace structure and places it in a per-cpu subbuffer.
- */
-static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
-		     int rw, u32 what, int error, int pdu_len, void *pdu_data)
-{
-	struct task_struct *tsk = current;
-	struct ring_buffer_event *event = NULL;
-	struct blk_io_trace *t;
-	unsigned long flags = 0;
-	unsigned long *sequence;
-	pid_t pid;
-	int cpu, pc = 0;
-
-	if (unlikely(bt->trace_state != Blktrace_running ||
-		     !blk_tracer_enabled))
-		return;
-
-	what |= ddir_act[rw & WRITE];
-	what |= MASK_TC_BIT(rw, BARRIER);
-	what |= MASK_TC_BIT(rw, SYNC);
-	what |= MASK_TC_BIT(rw, AHEAD);
-	what |= MASK_TC_BIT(rw, META);
-	what |= MASK_TC_BIT(rw, DISCARD);
-
-	pid = tsk->pid;
-	if (unlikely(act_log_check(bt, what, sector, pid)))
-		return;
-	cpu = raw_smp_processor_id();
-
-	if (blk_tr) {
-		tracing_record_cmdline(current);
-
-		pc = preempt_count();
-		event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
-						  sizeof(*t) + pdu_len,
-						  0, pc);
-		if (!event)
-			return;
-		t = ring_buffer_event_data(event);
-		goto record_it;
-	}
-
-	/*
-	 * A word about the locking here - we disable interrupts to reserve
-	 * some space in the relay per-cpu buffer, to prevent an irq
-	 * from coming in and stepping on our toes.
-	 */
-	local_irq_save(flags);
-
-	if (unlikely(tsk->btrace_seq != blktrace_seq))
-		trace_note_tsk(bt, tsk);
-
-	t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
-	if (t) {
-		sequence = per_cpu_ptr(bt->sequence, cpu);
-
-		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
-		t->sequence = ++(*sequence);
-		t->time = ktime_to_ns(ktime_get());
-record_it:
-		/*
-		 * These two are not needed in ftrace as they are in the
-		 * generic trace_entry, filled by tracing_generic_entry_update,
-		 * but for the trace_event->bin() synthesizer benefit we do it
-		 * here too.
-		 */
-		t->cpu = cpu;
-		t->pid = pid;
-
-		t->sector = sector;
-		t->bytes = bytes;
-		t->action = what;
-		t->device = bt->dev;
-		t->error = error;
-		t->pdu_len = pdu_len;
-
-		if (pdu_len)
-			memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
-
-		if (blk_tr) {
-			trace_buffer_unlock_commit(blk_tr, event, 0, pc);
-			return;
-		}
-	}
-
-	local_irq_restore(flags);
-}
-
-static struct dentry *blk_tree_root;
-static DEFINE_MUTEX(blk_tree_mutex);
-
-static void blk_trace_cleanup(struct blk_trace *bt)
-{
-	debugfs_remove(bt->msg_file);
-	debugfs_remove(bt->dropped_file);
-	relay_close(bt->rchan);
-	free_percpu(bt->sequence);
-	free_percpu(bt->msg_data);
-	kfree(bt);
-	mutex_lock(&blk_probe_mutex);
-	if (atomic_dec_and_test(&blk_probes_ref))
-		blk_unregister_tracepoints();
-	mutex_unlock(&blk_probe_mutex);
-}
-
-int blk_trace_remove(struct request_queue *q)
-{
-	struct blk_trace *bt;
-
-	bt = xchg(&q->blk_trace, NULL);
-	if (!bt)
-		return -EINVAL;
-
-	if (bt->trace_state == Blktrace_setup ||
-	    bt->trace_state == Blktrace_stopped)
-		blk_trace_cleanup(bt);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(blk_trace_remove);
-
-static int blk_dropped_open(struct inode *inode, struct file *filp)
-{
-	filp->private_data = inode->i_private;
-
-	return 0;
-}
-
-static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
-				size_t count, loff_t *ppos)
-{
-	struct blk_trace *bt = filp->private_data;
-	char buf[16];
-
-	snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
-
-	return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
-}
-
-static const struct file_operations blk_dropped_fops = {
-	.owner =	THIS_MODULE,
-	.open =		blk_dropped_open,
-	.read =		blk_dropped_read,
-};
-
-static int blk_msg_open(struct inode *inode, struct file *filp)
-{
-	filp->private_data = inode->i_private;
-
-	return 0;
-}
-
-static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
-				size_t count, loff_t *ppos)
-{
-	char *msg;
-	struct blk_trace *bt;
-
-	if (count > BLK_TN_MAX_MSG)
-		return -EINVAL;
-
-	msg = kmalloc(count, GFP_KERNEL);
-	if (msg == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(msg, buffer, count)) {
-		kfree(msg);
-		return -EFAULT;
-	}
-
-	bt = filp->private_data;
-	__trace_note_message(bt, "%s", msg);
-	kfree(msg);
-
-	return count;
-}
-
-static const struct file_operations blk_msg_fops = {
-	.owner =	THIS_MODULE,
-	.open =		blk_msg_open,
-	.write =	blk_msg_write,
-};
-
-/*
- * Keep track of how many times we encountered a full subbuffer, to aid
- * the user space app in telling how many lost events there were.
- */
-static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
-				     void *prev_subbuf, size_t prev_padding)
-{
-	struct blk_trace *bt;
-
-	if (!relay_buf_full(buf))
-		return 1;
-
-	bt = buf->chan->private_data;
-	atomic_inc(&bt->dropped);
-	return 0;
-}
-
-static int blk_remove_buf_file_callback(struct dentry *dentry)
-{
-	struct dentry *parent = dentry->d_parent;
-	debugfs_remove(dentry);
-
-	/*
-	* this will fail for all but the last file, but that is ok. what we
-	* care about is the top level buts->name directory going away, when
-	* the last trace file is gone. Then we don't have to rmdir() that
-	* manually on trace stop, so it nicely solves the issue with
-	* force killing of running traces.
-	*/
-
-	debugfs_remove(parent);
-	return 0;
-}
-
-static struct dentry *blk_create_buf_file_callback(const char *filename,
-						   struct dentry *parent,
-						   int mode,
-						   struct rchan_buf *buf,
-						   int *is_global)
-{
-	return debugfs_create_file(filename, mode, parent, buf,
-					&relay_file_operations);
-}
-
-static struct rchan_callbacks blk_relay_callbacks = {
-	.subbuf_start		= blk_subbuf_start_callback,
-	.create_buf_file	= blk_create_buf_file_callback,
-	.remove_buf_file	= blk_remove_buf_file_callback,
-};
-
-/*
- * Setup everything required to start tracing
- */
-int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
-			struct blk_user_trace_setup *buts)
-{
-	struct blk_trace *old_bt, *bt = NULL;
-	struct dentry *dir = NULL;
-	int ret, i;
-
-	if (!buts->buf_size || !buts->buf_nr)
-		return -EINVAL;
-
-	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
-	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
-
-	/*
-	 * some device names have larger paths - convert the slashes
-	 * to underscores for this to work as expected
-	 */
-	for (i = 0; i < strlen(buts->name); i++)
-		if (buts->name[i] == '/')
-			buts->name[i] = '_';
-
-	ret = -ENOMEM;
-	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
-	if (!bt)
-		goto err;
-
-	bt->sequence = alloc_percpu(unsigned long);
-	if (!bt->sequence)
-		goto err;
-
-	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
-	if (!bt->msg_data)
-		goto err;
-
-	ret = -ENOENT;
-
-	if (!blk_tree_root) {
-		blk_tree_root = debugfs_create_dir("block", NULL);
-		if (!blk_tree_root)
-			return -ENOMEM;
-	}
-
-	dir = debugfs_create_dir(buts->name, blk_tree_root);
-
-	if (!dir)
-		goto err;
-
-	bt->dir = dir;
-	bt->dev = dev;
-	atomic_set(&bt->dropped, 0);
-
-	ret = -EIO;
-	bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
-					       &blk_dropped_fops);
-	if (!bt->dropped_file)
-		goto err;
-
-	bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
-	if (!bt->msg_file)
-		goto err;
-
-	bt->rchan = relay_open("trace", dir, buts->buf_size,
-				buts->buf_nr, &blk_relay_callbacks, bt);
-	if (!bt->rchan)
-		goto err;
-
-	bt->act_mask = buts->act_mask;
-	if (!bt->act_mask)
-		bt->act_mask = (u16) -1;
-
-	bt->start_lba = buts->start_lba;
-	bt->end_lba = buts->end_lba;
-	if (!bt->end_lba)
-		bt->end_lba = -1ULL;
-
-	bt->pid = buts->pid;
-	bt->trace_state = Blktrace_setup;
-
-	mutex_lock(&blk_probe_mutex);
-	if (atomic_add_return(1, &blk_probes_ref) == 1) {
-		ret = blk_register_tracepoints();
-		if (ret)
-			goto probe_err;
-	}
-	mutex_unlock(&blk_probe_mutex);
-
-	ret = -EBUSY;
-	old_bt = xchg(&q->blk_trace, bt);
-	if (old_bt) {
-		(void) xchg(&q->blk_trace, old_bt);
-		goto err;
-	}
-
-	return 0;
-probe_err:
-	atomic_dec(&blk_probes_ref);
-	mutex_unlock(&blk_probe_mutex);
-err:
-	if (bt) {
-		if (bt->msg_file)
-			debugfs_remove(bt->msg_file);
-		if (bt->dropped_file)
-			debugfs_remove(bt->dropped_file);
-		free_percpu(bt->sequence);
-		free_percpu(bt->msg_data);
-		if (bt->rchan)
-			relay_close(bt->rchan);
-		kfree(bt);
-	}
-	return ret;
-}
-
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
-		    char __user *arg)
-{
-	struct blk_user_trace_setup buts;
-	int ret;
-
-	ret = copy_from_user(&buts, arg, sizeof(buts));
-	if (ret)
-		return -EFAULT;
-
-	ret = do_blk_trace_setup(q, name, dev, &buts);
-	if (ret)
-		return ret;
-
-	if (copy_to_user(arg, &buts, sizeof(buts)))
-		return -EFAULT;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(blk_trace_setup);
-
-int blk_trace_startstop(struct request_queue *q, int start)
-{
-	int ret;
-	struct blk_trace *bt = q->blk_trace;
-
-	if (bt == NULL)
-		return -EINVAL;
-
-	/*
-	 * For starting a trace, we can transition from a setup or stopped
-	 * trace. For stopping a trace, the state must be running
-	 */
-	ret = -EINVAL;
-	if (start) {
-		if (bt->trace_state == Blktrace_setup ||
-		    bt->trace_state == Blktrace_stopped) {
-			blktrace_seq++;
-			smp_mb();
-			bt->trace_state = Blktrace_running;
-
-			trace_note_time(bt);
-			ret = 0;
-		}
-	} else {
-		if (bt->trace_state == Blktrace_running) {
-			bt->trace_state = Blktrace_stopped;
-			relay_flush(bt->rchan);
-			ret = 0;
-		}
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(blk_trace_startstop);
-
-/**
- * blk_trace_ioctl: - handle the ioctls associated with tracing
- * @bdev:	the block device
- * @cmd: 	the ioctl cmd
- * @arg:	the argument data, if any
- *
- **/
-int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
-{
-	struct request_queue *q;
-	int ret, start = 0;
-	char b[BDEVNAME_SIZE];
-
-	q = bdev_get_queue(bdev);
-	if (!q)
-		return -ENXIO;
-
-	mutex_lock(&bdev->bd_mutex);
-
-	switch (cmd) {
-	case BLKTRACESETUP:
-		bdevname(bdev, b);
-		ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
-		break;
-	case BLKTRACESTART:
-		start = 1;
-	case BLKTRACESTOP:
-		ret = blk_trace_startstop(q, start);
-		break;
-	case BLKTRACETEARDOWN:
-		ret = blk_trace_remove(q);
-		break;
-	default:
-		ret = -ENOTTY;
-		break;
-	}
-
-	mutex_unlock(&bdev->bd_mutex);
-	return ret;
-}
-
-/**
- * blk_trace_shutdown: - stop and cleanup trace structures
- * @q:    the request queue associated with the device
- *
- **/
-void blk_trace_shutdown(struct request_queue *q)
-{
-	if (q->blk_trace) {
-		blk_trace_startstop(q, 0);
-		blk_trace_remove(q);
-	}
-}
-
-/*
- * blktrace probes
- */
-
-/**
- * blk_add_trace_rq - Add a trace for a request oriented action
- * @q:		queue the io is for
- * @rq:		the source request
- * @what:	the action
- *
- * Description:
- *     Records an action against a request. Will log the bio offset + size.
- *
- **/
-static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
-				    u32 what)
-{
-	struct blk_trace *bt = q->blk_trace;
-	int rw = rq->cmd_flags & 0x03;
-
-	if (likely(!bt))
-		return;
-
-	if (blk_discard_rq(rq))
-		rw |= (1 << BIO_RW_DISCARD);
-
-	if (blk_pc_request(rq)) {
-		what |= BLK_TC_ACT(BLK_TC_PC);
-		__blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
-				sizeof(rq->cmd), rq->cmd);
-	} else  {
-		what |= BLK_TC_ACT(BLK_TC_FS);
-		__blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
-				rw, what, rq->errors, 0, NULL);
-	}
-}
-
-static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
-{
-	blk_add_trace_rq(q, rq, BLK_TA_ABORT);
-}
-
-static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
-{
-	blk_add_trace_rq(q, rq, BLK_TA_INSERT);
-}
-
-static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
-{
-	blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
-}
-
-static void blk_add_trace_rq_requeue(struct request_queue *q,
-				     struct request *rq)
-{
-	blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
-}
-
-static void blk_add_trace_rq_complete(struct request_queue *q,
-				      struct request *rq)
-{
-	blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
-}
-
-/**
- * blk_add_trace_bio - Add a trace for a bio oriented action
- * @q:		queue the io is for
- * @bio:	the source bio
- * @what:	the action
- *
- * Description:
- *     Records an action against a bio. Will log the bio offset + size.
- *
- **/
-static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
-				     u32 what)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (likely(!bt))
-		return;
-
-	__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
-			!bio_flagged(bio, BIO_UPTODATE), 0, NULL);
-}
-
-static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
-{
-	blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
-}
-
-static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
-{
-	blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
-}
-
-static void blk_add_trace_bio_backmerge(struct request_queue *q,
-					struct bio *bio)
-{
-	blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
-}
-
-static void blk_add_trace_bio_frontmerge(struct request_queue *q,
-					 struct bio *bio)
-{
-	blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
-}
-
-static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
-{
-	blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
-}
-
-static void blk_add_trace_getrq(struct request_queue *q,
-				struct bio *bio, int rw)
-{
-	if (bio)
-		blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
-	else {
-		struct blk_trace *bt = q->blk_trace;
-
-		if (bt)
-			__blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
-	}
-}
-
-
-static void blk_add_trace_sleeprq(struct request_queue *q,
-				  struct bio *bio, int rw)
-{
-	if (bio)
-		blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
-	else {
-		struct blk_trace *bt = q->blk_trace;
-
-		if (bt)
-			__blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
-					0, 0, NULL);
-	}
-}
-
-static void blk_add_trace_plug(struct request_queue *q)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (bt)
-		__blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
-}
-
-static void blk_add_trace_unplug_io(struct request_queue *q)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (bt) {
-		unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
-		__be64 rpdu = cpu_to_be64(pdu);
-
-		__blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
-				sizeof(rpdu), &rpdu);
-	}
-}
-
-static void blk_add_trace_unplug_timer(struct request_queue *q)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (bt) {
-		unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
-		__be64 rpdu = cpu_to_be64(pdu);
-
-		__blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
-				sizeof(rpdu), &rpdu);
-	}
-}
-
-static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
-				unsigned int pdu)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (bt) {
-		__be64 rpdu = cpu_to_be64(pdu);
-
-		__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
-				BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
-				sizeof(rpdu), &rpdu);
-	}
-}
-
-/**
- * blk_add_trace_remap - Add a trace for a remap operation
- * @q:		queue the io is for
- * @bio:	the source bio
- * @dev:	target device
- * @from:	source sector
- * @to:		target sector
- *
- * Description:
- *     Device mapper or raid target sometimes need to split a bio because
- *     it spans a stripe (or similar). Add a trace for that action.
- *
- **/
-static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
-				       dev_t dev, sector_t from, sector_t to)
-{
-	struct blk_trace *bt = q->blk_trace;
-	struct blk_io_trace_remap r;
-
-	if (likely(!bt))
-		return;
-
-	r.device = cpu_to_be32(dev);
-	r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
-	r.sector = cpu_to_be64(to);
-
-	__blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
-			!bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
-}
-
-/**
- * blk_add_driver_data - Add binary message with driver-specific data
- * @q:		queue the io is for
- * @rq:		io request
- * @data:	driver-specific data
- * @len:	length of driver-specific data
- *
- * Description:
- *     Some drivers might want to write driver-specific data per request.
- *
- **/
-void blk_add_driver_data(struct request_queue *q,
-			 struct request *rq,
-			 void *data, size_t len)
-{
-	struct blk_trace *bt = q->blk_trace;
-
-	if (likely(!bt))
-		return;
-
-	if (blk_pc_request(rq))
-		__blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
-				rq->errors, len, data);
-	else
-		__blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
-				0, BLK_TA_DRV_DATA, rq->errors, len, data);
-}
-EXPORT_SYMBOL_GPL(blk_add_driver_data);
-
-static int blk_register_tracepoints(void)
-{
-	int ret;
-
-	ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
-	WARN_ON(ret);
-	ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
-	WARN_ON(ret);
-	ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
-	WARN_ON(ret);
-	ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
-	WARN_ON(ret);
-	ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
-	WARN_ON(ret);
-	ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
-	WARN_ON(ret);
-	ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
-	WARN_ON(ret);
-	ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
-	WARN_ON(ret);
-	ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
-	WARN_ON(ret);
-	ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
-	WARN_ON(ret);
-	ret = register_trace_block_getrq(blk_add_trace_getrq);
-	WARN_ON(ret);
-	ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
-	WARN_ON(ret);
-	ret = register_trace_block_plug(blk_add_trace_plug);
-	WARN_ON(ret);
-	ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
-	WARN_ON(ret);
-	ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
-	WARN_ON(ret);
-	ret = register_trace_block_split(blk_add_trace_split);
-	WARN_ON(ret);
-	ret = register_trace_block_remap(blk_add_trace_remap);
-	WARN_ON(ret);
-	return 0;
-}
-
-static void blk_unregister_tracepoints(void)
-{
-	unregister_trace_block_remap(blk_add_trace_remap);
-	unregister_trace_block_split(blk_add_trace_split);
-	unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
-	unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
-	unregister_trace_block_plug(blk_add_trace_plug);
-	unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
-	unregister_trace_block_getrq(blk_add_trace_getrq);
-	unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
-	unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
-	unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
-	unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
-	unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
-	unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
-	unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
-	unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
-	unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
-	unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
-
-	tracepoint_synchronize_unregister();
-}
-
-/*
- * struct blk_io_tracer formatting routines
- */
-
-static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
-{
-	int i = 0;
-
-	if (t->action & BLK_TC_DISCARD)
-		rwbs[i++] = 'D';
-	else if (t->action & BLK_TC_WRITE)
-		rwbs[i++] = 'W';
-	else if (t->bytes)
-		rwbs[i++] = 'R';
-	else
-		rwbs[i++] = 'N';
-
-	if (t->action & BLK_TC_AHEAD)
-		rwbs[i++] = 'A';
-	if (t->action & BLK_TC_BARRIER)
-		rwbs[i++] = 'B';
-	if (t->action & BLK_TC_SYNC)
-		rwbs[i++] = 'S';
-	if (t->action & BLK_TC_META)
-		rwbs[i++] = 'M';
-
-	rwbs[i] = '\0';
-}
-
-static inline
-const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
-{
-	return (const struct blk_io_trace *)ent;
-}
-
-static inline const void *pdu_start(const struct trace_entry *ent)
-{
-	return te_blk_io_trace(ent) + 1;
-}
-
-static inline u32 t_sec(const struct trace_entry *ent)
-{
-	return te_blk_io_trace(ent)->bytes >> 9;
-}
-
-static inline unsigned long long t_sector(const struct trace_entry *ent)
-{
-	return te_blk_io_trace(ent)->sector;
-}
-
-static inline __u16 t_error(const struct trace_entry *ent)
-{
-	return te_blk_io_trace(ent)->sector;
-}
-
-static __u64 get_pdu_int(const struct trace_entry *ent)
-{
-	const __u64 *val = pdu_start(ent);
-	return be64_to_cpu(*val);
-}
-
-static void get_pdu_remap(const struct trace_entry *ent,
-			  struct blk_io_trace_remap *r)
-{
-	const struct blk_io_trace_remap *__r = pdu_start(ent);
-	__u64 sector = __r->sector;
-
-	r->device = be32_to_cpu(__r->device);
-	r->device_from = be32_to_cpu(__r->device_from);
-	r->sector = be64_to_cpu(sector);
-}
-
-static int blk_log_action_iter(struct trace_iterator *iter, const char *act)
-{
-	char rwbs[6];
-	unsigned long long ts  = ns2usecs(iter->ts);
-	unsigned long usec_rem = do_div(ts, USEC_PER_SEC);
-	unsigned secs	       = (unsigned long)ts;
-	const struct trace_entry *ent = iter->ent;
-	const struct blk_io_trace *t = (const struct blk_io_trace *)ent;
-
-	fill_rwbs(rwbs, t);
-
-	return trace_seq_printf(&iter->seq,
-				"%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), iter->cpu,
-				secs, usec_rem, ent->pid, act, rwbs);
-}
-
-static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t,
-			      const char *act)
-{
-	char rwbs[6];
-	fill_rwbs(rwbs, t);
-	return trace_seq_printf(s, "%3d,%-3d %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), act, rwbs);
-}
-
-static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
-{
-	const char *cmd = trace_find_cmdline(ent->pid);
-
-	if (t_sec(ent))
-		return trace_seq_printf(s, "%llu + %u [%s]\n",
-					t_sector(ent), t_sec(ent), cmd);
-	return trace_seq_printf(s, "[%s]\n", cmd);
-}
-
-static int blk_log_with_error(struct trace_seq *s,
-			      const struct trace_entry *ent)
-{
-	if (t_sec(ent))
-		return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent),
-					t_sec(ent), t_error(ent));
-	return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent));
-}
-
-static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
-{
-	struct blk_io_trace_remap r = { .device = 0, };
-
-	get_pdu_remap(ent, &r);
-	return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
-			       t_sector(ent),
-			       t_sec(ent), MAJOR(r.device), MINOR(r.device),
-			       (unsigned long long)r.sector);
-}
-
-static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
-{
-	return trace_seq_printf(s, "[%s]\n", trace_find_cmdline(ent->pid));
-}
-
-static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
-{
-	return trace_seq_printf(s, "[%s] %llu\n", trace_find_cmdline(ent->pid),
-				get_pdu_int(ent));
-}
-
-static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
-{
-	return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
-				get_pdu_int(ent), trace_find_cmdline(ent->pid));
-}
-
-/*
- * struct tracer operations
- */
-
-static void blk_tracer_print_header(struct seq_file *m)
-{
-	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
-		return;
-	seq_puts(m, "# DEV   CPU TIMESTAMP     PID ACT FLG\n"
-		    "#  |     |     |           |   |   |\n");
-}
-
-static void blk_tracer_start(struct trace_array *tr)
-{
-	mutex_lock(&blk_probe_mutex);
-	if (atomic_add_return(1, &blk_probes_ref) == 1)
-		if (blk_register_tracepoints())
-			atomic_dec(&blk_probes_ref);
-	mutex_unlock(&blk_probe_mutex);
-	trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
-}
-
-static int blk_tracer_init(struct trace_array *tr)
-{
-	blk_tr = tr;
-	blk_tracer_start(tr);
-	mutex_lock(&blk_probe_mutex);
-	blk_tracer_enabled++;
-	mutex_unlock(&blk_probe_mutex);
-	return 0;
-}
-
-static void blk_tracer_stop(struct trace_array *tr)
-{
-	trace_flags |= TRACE_ITER_CONTEXT_INFO;
-	mutex_lock(&blk_probe_mutex);
-	if (atomic_dec_and_test(&blk_probes_ref))
-		blk_unregister_tracepoints();
-	mutex_unlock(&blk_probe_mutex);
-}
-
-static void blk_tracer_reset(struct trace_array *tr)
-{
-	if (!atomic_read(&blk_probes_ref))
-		return;
-
-	mutex_lock(&blk_probe_mutex);
-	blk_tracer_enabled--;
-	WARN_ON(blk_tracer_enabled < 0);
-	mutex_unlock(&blk_probe_mutex);
-
-	blk_tracer_stop(tr);
-}
-
-static struct {
-	const char *act[2];
-	int 	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
-} what2act[] __read_mostly = {
-	[__BLK_TA_QUEUE]	= {{  "Q", "queue" }, 	   blk_log_generic },
-	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
-	[__BLK_TA_FRONTMERGE]	= {{  "F", "frontmerge" }, blk_log_generic },
-	[__BLK_TA_GETRQ]	= {{  "G", "getrq" },	   blk_log_generic },
-	[__BLK_TA_SLEEPRQ]	= {{  "S", "sleeprq" },	   blk_log_generic },
-	[__BLK_TA_REQUEUE]	= {{  "R", "requeue" },	   blk_log_with_error },
-	[__BLK_TA_ISSUE]	= {{  "D", "issue" },	   blk_log_generic },
-	[__BLK_TA_COMPLETE]	= {{  "C", "complete" },   blk_log_with_error },
-	[__BLK_TA_PLUG]		= {{  "P", "plug" },	   blk_log_plug },
-	[__BLK_TA_UNPLUG_IO]	= {{  "U", "unplug_io" },  blk_log_unplug },
-	[__BLK_TA_UNPLUG_TIMER]	= {{ "UT", "unplug_timer" }, blk_log_unplug },
-	[__BLK_TA_INSERT]	= {{  "I", "insert" },	   blk_log_generic },
-	[__BLK_TA_SPLIT]	= {{  "X", "split" },	   blk_log_split },
-	[__BLK_TA_BOUNCE]	= {{  "B", "bounce" },	   blk_log_generic },
-	[__BLK_TA_REMAP]	= {{  "A", "remap" },	   blk_log_remap },
-};
-
-static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
-					       int flags)
-{
-	struct trace_seq *s = &iter->seq;
-	const struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
-	const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
-	int ret;
-
-	if (!trace_print_context(iter))
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
-		ret = trace_seq_printf(s, "Bad pc action %x\n", what);
-	else {
-		const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
-		ret = blk_log_action_seq(s, t, what2act[what].act[long_act]);
-		if (ret)
-			ret = what2act[what].print(s, iter->ent);
-	}
-
-	return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
-{
-	struct trace_seq *s = &iter->seq;
-	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
-	const int offset = offsetof(struct blk_io_trace, sector);
-	struct blk_io_trace old = {
-		.magic	  = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
-		.time     = ns2usecs(iter->ts),
-	};
-
-	if (!trace_seq_putmem(s, &old, offset))
-		return 0;
-	return trace_seq_putmem(s, &t->sector,
-				sizeof(old) - offset + t->pdu_len);
-}
-
-static enum print_line_t
-blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
-{
-	return blk_trace_synthesize_old_trace(iter) ?
-			TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
-{
-	const struct blk_io_trace *t;
-	u16 what;
-	int ret;
-
-	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
-		return TRACE_TYPE_UNHANDLED;
-
-	t = (const struct blk_io_trace *)iter->ent;
-	what = t->action & ((1 << BLK_TC_SHIFT) - 1);
-
-	if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
-		ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what);
-	else {
-		const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
-		ret = blk_log_action_iter(iter, what2act[what].act[long_act]);
-		if (ret)
-			ret = what2act[what].print(&iter->seq, iter->ent);
-	}
-
-	return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static struct tracer blk_tracer __read_mostly = {
-	.name		= "blk",
-	.init		= blk_tracer_init,
-	.reset		= blk_tracer_reset,
-	.start		= blk_tracer_start,
-	.stop		= blk_tracer_stop,
-	.print_header	= blk_tracer_print_header,
-	.print_line	= blk_tracer_print_line,
-	.flags		= &blk_tracer_flags,
-};
-
-static struct trace_event trace_blk_event = {
-	.type	 	= TRACE_BLK,
-	.trace		= blk_trace_event_print,
-	.latency_trace	= blk_trace_event_print,
-	.binary		= blk_trace_event_print_binary,
-};
-
-static int __init init_blk_tracer(void)
-{
-	if (!register_ftrace_event(&trace_blk_event)) {
-		pr_warning("Warning: could not register block events\n");
-		return 1;
-	}
-
-	if (register_tracer(&blk_tracer) != 0) {
-		pr_warning("Warning: could not register the block tracer\n");
-		unregister_ftrace_event(&trace_blk_event);
-		return 1;
-	}
-
-	return 0;
-}
-
-device_initcall(init_blk_tracer);
-
-static int blk_trace_remove_queue(struct request_queue *q)
-{
-	struct blk_trace *bt;
-
-	bt = xchg(&q->blk_trace, NULL);
-	if (bt == NULL)
-		return -EINVAL;
-
-	kfree(bt);
-	return 0;
-}
-
-/*
- * Setup everything required to start tracing
- */
-static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
-{
-	struct blk_trace *old_bt, *bt = NULL;
-	int ret;
-
-	ret = -ENOMEM;
-	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
-	if (!bt)
-		goto err;
-
-	bt->dev = dev;
-	bt->act_mask = (u16)-1;
-	bt->end_lba = -1ULL;
-	bt->trace_state = Blktrace_running;
-
-	old_bt = xchg(&q->blk_trace, bt);
-	if (old_bt != NULL) {
-		(void)xchg(&q->blk_trace, old_bt);
-		kfree(bt);
-		ret = -EBUSY;
-	}
-	return 0;
-err:
-	return ret;
-}
-
-/*
- * sysfs interface to enable and configure tracing
- */
-
-static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
-					   struct device_attribute *attr,
-					   char *buf)
-{
-	struct hd_struct *p = dev_to_part(dev);
-	struct block_device *bdev;
-	ssize_t ret = -ENXIO;
-
-	lock_kernel();
-	bdev = bdget(part_devt(p));
-	if (bdev != NULL) {
-		struct request_queue *q = bdev_get_queue(bdev);
-
-		if (q != NULL) {
-			mutex_lock(&bdev->bd_mutex);
-			ret = sprintf(buf, "%u\n", !!q->blk_trace);
-			mutex_unlock(&bdev->bd_mutex);
-		}
-
-		bdput(bdev);
-	}
-
-	unlock_kernel();
-	return ret;
-}
-
-static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
-					    struct device_attribute *attr,
-					    const char *buf, size_t count)
-{
-	struct block_device *bdev;
-	struct request_queue *q;
-	struct hd_struct *p;
-	int value;
-	ssize_t ret = -ENXIO;
-
-	if (count == 0 || sscanf(buf, "%d", &value) != 1)
-		goto out;
-
-	lock_kernel();
-	p = dev_to_part(dev);
-	bdev = bdget(part_devt(p));
-	if (bdev == NULL)
-		goto out_unlock_kernel;
-
-	q = bdev_get_queue(bdev);
-	if (q == NULL)
-		goto out_bdput;
-
-	mutex_lock(&bdev->bd_mutex);
-	if (value)
-		ret = blk_trace_setup_queue(q, bdev->bd_dev);
-	else
-		ret = blk_trace_remove_queue(q);
-	mutex_unlock(&bdev->bd_mutex);
-
-	if (ret == 0)
-		ret = count;
-out_bdput:
-	bdput(bdev);
-out_unlock_kernel:
-	unlock_kernel();
-out:
-	return ret;
-}
-
-static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
-					 struct device_attribute *attr,
-					 char *buf);
-static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
-					  struct device_attribute *attr,
-					  const char *buf, size_t count);
-#define BLK_TRACE_DEVICE_ATTR(_name) \
-	DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
-		    sysfs_blk_trace_attr_show, \
-		    sysfs_blk_trace_attr_store)
-
-static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
-		   sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
-static BLK_TRACE_DEVICE_ATTR(act_mask);
-static BLK_TRACE_DEVICE_ATTR(pid);
-static BLK_TRACE_DEVICE_ATTR(start_lba);
-static BLK_TRACE_DEVICE_ATTR(end_lba);
-
-static struct attribute *blk_trace_attrs[] = {
-	&dev_attr_enable.attr,
-	&dev_attr_act_mask.attr,
-	&dev_attr_pid.attr,
-	&dev_attr_start_lba.attr,
-	&dev_attr_end_lba.attr,
-	NULL
-};
-
-struct attribute_group blk_trace_attr_group = {
-	.name  = "trace",
-	.attrs = blk_trace_attrs,
-};
-
-static int blk_str2act_mask(const char *str)
-{
-	int mask = 0;
-	char *copy = kstrdup(str, GFP_KERNEL), *s;
-
-	if (copy == NULL)
-		return -ENOMEM;
-
-	s = strstrip(copy);
-
-	while (1) {
-		char *sep = strchr(s, ',');
-
-		if (sep != NULL)
-			*sep = '\0';
-
-		if (strcasecmp(s, "barrier") == 0)
-			mask |= BLK_TC_BARRIER;
-		else if (strcasecmp(s, "complete") == 0)
-			mask |= BLK_TC_COMPLETE;
-		else if (strcasecmp(s, "fs") == 0)
-			mask |= BLK_TC_FS;
-		else if (strcasecmp(s, "issue") == 0)
-			mask |= BLK_TC_ISSUE;
-		else if (strcasecmp(s, "pc") == 0)
-			mask |= BLK_TC_PC;
-		else if (strcasecmp(s, "queue") == 0)
-			mask |= BLK_TC_QUEUE;
-		else if (strcasecmp(s, "read") == 0)
-			mask |= BLK_TC_READ;
-		else if (strcasecmp(s, "requeue") == 0)
-			mask |= BLK_TC_REQUEUE;
-		else if (strcasecmp(s, "sync") == 0)
-			mask |= BLK_TC_SYNC;
-		else if (strcasecmp(s, "write") == 0)
-			mask |= BLK_TC_WRITE;
-
-		if (sep == NULL)
-			break;
-
-		s = sep + 1;
-	}
-	kfree(copy);
-
-	return mask;
-}
-
-static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
-					 struct device_attribute *attr,
-					 char *buf)
-{
-	struct hd_struct *p = dev_to_part(dev);
-	struct request_queue *q;
-	struct block_device *bdev;
-	ssize_t ret = -ENXIO;
-
-	lock_kernel();
-	bdev = bdget(part_devt(p));
-	if (bdev == NULL)
-		goto out_unlock_kernel;
-
-	q = bdev_get_queue(bdev);
-	if (q == NULL)
-		goto out_bdput;
-	mutex_lock(&bdev->bd_mutex);
-	if (q->blk_trace == NULL)
-		ret = sprintf(buf, "disabled\n");
-	else if (attr == &dev_attr_act_mask)
-		ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
-	else if (attr == &dev_attr_pid)
-		ret = sprintf(buf, "%u\n", q->blk_trace->pid);
-	else if (attr == &dev_attr_start_lba)
-		ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
-	else if (attr == &dev_attr_end_lba)
-		ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
-	mutex_unlock(&bdev->bd_mutex);
-out_bdput:
-	bdput(bdev);
-out_unlock_kernel:
-	unlock_kernel();
-	return ret;
-}
-
-static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
-					  struct device_attribute *attr,
-					  const char *buf, size_t count)
-{
-	struct block_device *bdev;
-	struct request_queue *q;
-	struct hd_struct *p;
-	u64 value;
-	ssize_t ret = -ENXIO;
-
-	if (count == 0)
-		goto out;
-
-	if (attr == &dev_attr_act_mask) {
-		if (sscanf(buf, "%llx", &value) != 1) {
-			/* Assume it is a list of trace category names */
-			value = blk_str2act_mask(buf);
-			if (value < 0)
-				goto out;
-		}
-	} else if (sscanf(buf, "%llu", &value) != 1)
-		goto out;
-
-	lock_kernel();
-	p = dev_to_part(dev);
-	bdev = bdget(part_devt(p));
-	if (bdev == NULL)
-		goto out_unlock_kernel;
-
-	q = bdev_get_queue(bdev);
-	if (q == NULL)
-		goto out_bdput;
-
-	mutex_lock(&bdev->bd_mutex);
-	ret = 0;
-	if (q->blk_trace == NULL)
-		ret = blk_trace_setup_queue(q, bdev->bd_dev);
-
-	if (ret == 0) {
-		if (attr == &dev_attr_act_mask)
-			q->blk_trace->act_mask = value;
-		else if (attr == &dev_attr_pid)
-			q->blk_trace->pid = value;
-		else if (attr == &dev_attr_start_lba)
-			q->blk_trace->start_lba = value;
-		else if (attr == &dev_attr_end_lba)
-			q->blk_trace->end_lba = value;
-		ret = count;
-	}
-	mutex_unlock(&bdev->bd_mutex);
-out_bdput:
-	bdput(bdev);
-out_unlock_kernel:
-	unlock_kernel();
-out:
-	return ret;
-}