Commit 42da88a7 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by Jens Axboe
Browse files

blktrace: split do_blk_trace_setup into two functions 



Split do_blk_trace_setup into two functions, this is done to prepare for
an incoming new BLKTRACESETUP2 ioctl(2) which can receive extended
parameters from user-space.

Also move the size verification logic to the callers in preparation for
using a new internal structure later.

Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 370cd70a

kernel/trace/blktrace.c

+56 −38
Original line number Diff line number Diff line
@@ -518,9 +518,10 @@ static void blk_trace_setup_lba(struct blk_trace *bt, 
/*

 * Setup everything required to start tracing

 */

static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,

			      struct block_device *bdev,

			      struct blk_user_trace_setup *buts)

static struct blk_trace *blk_trace_setup_prepare(struct request_queue *q,

						 char *name, dev_t dev,

						 u32 buf_size, u32 buf_nr,

						 struct block_device *bdev)

{

	struct blk_trace *bt = NULL;

	struct dentry *dir = NULL;
@@ -528,31 +529,19 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 


	lockdep_assert_held(&q->debugfs_mutex);



	if (!buts->buf_size || !buts->buf_nr)

		return -EINVAL;



	strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE);



	/*

	 * some device names have larger paths - convert the slashes

	 * to underscores for this to work as expected

	 */

	strreplace(buts->name, '/', '_');



	/*

	 * bdev can be NULL, as with scsi-generic, this is a helpful as

	 * we can be.

	 */

	if (rcu_dereference_protected(q->blk_trace,

				      lockdep_is_held(&q->debugfs_mutex))) {

		pr_warn("Concurrent blktraces are not allowed on %s\n",

			buts->name);

		return -EBUSY;

		pr_warn("Concurrent blktraces are not allowed on %s\n", name);

		return ERR_PTR(-EBUSY);

	}



	bt = kzalloc(sizeof(*bt), GFP_KERNEL);

	if (!bt)

		return -ENOMEM;

		return ERR_PTR(-ENOMEM);



	ret = -ENOMEM;

	bt->sequence = alloc_percpu(unsigned long);
@@ -572,7 +561,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	if (bdev && !bdev_is_partition(bdev))

		dir = q->debugfs_dir;

	else

		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);

		bt->dir = dir = debugfs_create_dir(name, blk_debugfs_root);



	/*

	 * As blktrace relies on debugfs for its interface the debugfs directory
@@ -580,8 +569,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	 * files or directories.

	 */

	if (IS_ERR_OR_NULL(dir)) {

		pr_warn("debugfs_dir not present for %s so skipping\n",

			buts->name);

		pr_warn("debugfs_dir not present for %s so skipping\n", name);

		ret = -ENOENT;

		goto err;

	}
@@ -593,17 +581,38 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);

	debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);



	bt->rchan = relay_open("trace", dir, buts->buf_size,

				buts->buf_nr, &blk_relay_callbacks, bt);

	bt->rchan = relay_open("trace", dir, buf_size, buf_nr,

			       &blk_relay_callbacks, bt);

	if (!bt->rchan)

		goto err;



	blk_trace_setup_lba(bt, bdev);



	return bt;



err:

	blk_trace_free(q, bt);



	return ERR_PTR(ret);

}



static void blk_trace_setup_finalize(struct request_queue *q,

				     char *name, struct blk_trace *bt,

				     struct blk_user_trace_setup *buts)



{

	strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE);



	/*

	 * some device names have larger paths - convert the slashes

	 * to underscores for this to work as expected

	 */

	strreplace(buts->name, '/', '_');



	bt->act_mask = buts->act_mask;

	if (!bt->act_mask)

		bt->act_mask = (u16) -1;



	blk_trace_setup_lba(bt, bdev);



	/* overwrite with user settings */

	if (buts->start_lba)

		bt->start_lba = buts->start_lba;
@@ -615,12 +624,6 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 


	rcu_assign_pointer(q->blk_trace, bt);

	get_probe_ref();



	ret = 0;

err:

	if (ret)

		blk_trace_free(q, bt);

	return ret;

}



int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
@@ -628,17 +631,25 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
		    char __user *arg)

{

	struct blk_user_trace_setup buts;

	struct blk_trace *bt;

	int ret;



	ret = copy_from_user(&buts, arg, sizeof(buts));

	if (ret)

		return -EFAULT;



	if (!buts.buf_size || !buts.buf_nr)

		return -EINVAL;



	mutex_lock(&q->debugfs_mutex);

	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);

	bt = blk_trace_setup_prepare(q, name, dev, buts.buf_size, buts.buf_nr,

				     bdev);

	if (IS_ERR(bt)) {

		mutex_unlock(&q->debugfs_mutex);

		return PTR_ERR(bt);

	}

	blk_trace_setup_finalize(q, name, bt, &buts);

	mutex_unlock(&q->debugfs_mutex);

	if (ret)

		return ret;



	if (copy_to_user(arg, &buts, sizeof(buts))) {

		blk_trace_remove(q);
@@ -655,11 +666,14 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name, 
{

	struct blk_user_trace_setup buts;

	struct compat_blk_user_trace_setup cbuts;

	int ret;

	struct blk_trace *bt;



	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))

		return -EFAULT;



	if (!cbuts.buf_size || !cbuts.buf_nr)

		return -EINVAL;



	buts = (struct blk_user_trace_setup) {

		.act_mask = cbuts.act_mask,

		.buf_size = cbuts.buf_size,
@@ -670,10 +684,14 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name, 
	};



	mutex_lock(&q->debugfs_mutex);

	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);

	bt = blk_trace_setup_prepare(q, name, dev, buts.buf_size, buts.buf_nr,

				     bdev);

	if (IS_ERR(bt)) {

		mutex_unlock(&q->debugfs_mutex);

		return PTR_ERR(bt);

	}

	blk_trace_setup_finalize(q, name, bt, &buts);

	mutex_unlock(&q->debugfs_mutex);

	if (ret)

		return ret;



	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {

		blk_trace_remove(q);