Implementation of module management interface functions. At this level,
the input and output parameters are converted and the corresponding
subsystems of the module are called.

Signed-off-by: Sergei Shtepa <sergei.shtepa@veeam.com>
---
 drivers/block/blksnap/ctrl.c | 410 +++++++++++++++++++++++++++++++++++
 drivers/block/blksnap/ctrl.h |   9 +
 2 files changed, 419 insertions(+)
 create mode 100644 drivers/block/blksnap/ctrl.c
 create mode 100644 drivers/block/blksnap/ctrl.h

diff --git a/drivers/block/blksnap/ctrl.c b/drivers/block/blksnap/ctrl.c
new file mode 100644
index 000000000000..990ffb004db3
--- /dev/null
+++ b/drivers/block/blksnap/ctrl.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME "-ctrl: " fmt
+
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <uapi/linux/blksnap.h>
+#include "ctrl.h"
+#include "params.h"
+#include "version.h"
+#include "snapshot.h"
+#include "snapimage.h"
+#include "tracker.h"
+
+static_assert(sizeof(uuid_t) == sizeof(struct blk_snap_uuid),
+	"Invalid size of struct blk_snap_uuid or uuid_t.");
+
+static int blk_snap_major;
+
+static long ctrl_unlocked_ioctl(struct file *filp, unsigned int cmd,
+				unsigned long arg);
+
+static const struct file_operations ctrl_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = ctrl_unlocked_ioctl,
+};
+
+static const struct blk_snap_version version = {
+	.major = VERSION_MAJOR,
+	.minor = VERSION_MINOR,
+	.revision = VERSION_REVISION,
+	.build = VERSION_BUILD,
+};
+
+int get_blk_snap_major(void)
+{
+	return blk_snap_major;
+}
+
+int ctrl_init(void)
+{
+	int ret;
+
+	ret = register_chrdev(0, THIS_MODULE->name, &ctrl_fops);
+	if (ret < 0) {
+		pr_err("Failed to register a character device. errno=%d\n",
+		       abs(blk_snap_major));
+		return ret;
+	}
+
+	blk_snap_major = ret;
+	pr_info("Register control device [%d:0].\n", blk_snap_major);
+	return 0;
+}
+
+void ctrl_done(void)
+{
+	pr_info("Unregister control device\n");
+
+	unregister_chrdev(blk_snap_major, THIS_MODULE->name);
+}
+
+static int ioctl_version(unsigned long arg)
+{
+	if (copy_to_user((void *)arg, &version, sizeof(version))) {
+		pr_err("Unable to get version: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	return 0;
+}
+
+static int ioctl_tracker_remove(unsigned long arg)
+{
+	struct blk_snap_tracker_remove karg;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg)) != 0) {
+		pr_err("Unable to remove device from tracking: invalid user buffer\n");
+		return -ENODATA;
+	}
+	return tracker_remove(MKDEV(karg.dev_id.mj, karg.dev_id.mn));
+}
+
+static int ioctl_tracker_collect(unsigned long arg)
+{
+	int res;
+	struct blk_snap_tracker_collect karg;
+	struct blk_snap_cbt_info *cbt_info = NULL;
+
+	pr_debug("Collecting tracking devices\n");
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to collect tracking devices: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	if (!karg.cbt_info_array) {
+		/*
+		 * If the buffer is empty, this is a request to determine
+		 * the number of trackers.
+		 */
+		res = tracker_collect(0, NULL, &karg.count);
+		if (res) {
+			pr_err("Failed to execute tracker_collect. errno=%d\n",
+			       abs(res));
+			return res;
+		}
+		if (copy_to_user((void *)arg, (void *)&karg, sizeof(karg))) {
+			pr_err("Unable to collect tracking devices: invalid user buffer for arguments\n");
+			return -ENODATA;
+		}
+		return 0;
+	}
+
+	cbt_info = kcalloc(karg.count, sizeof(struct blk_snap_cbt_info),
+			   GFP_KERNEL);
+	if (cbt_info == NULL)
+		return -ENOMEM;
+
+	res = tracker_collect(karg.count, cbt_info, &karg.count);
+	if (res) {
+		pr_err("Failed to execute tracker_collect. errno=%d\n",
+		       abs(res));
+		goto fail;
+	}
+
+	if (copy_to_user(karg.cbt_info_array, cbt_info,
+			 karg.count * sizeof(struct blk_snap_cbt_info))) {
+		pr_err("Unable to collect tracking devices: invalid user buffer for CBT info\n");
+		res = -ENODATA;
+		goto fail;
+	}
+
+	if (copy_to_user((void *)arg, (void *)&karg, sizeof(karg))) {
+		pr_err("Unable to collect tracking devices: invalid user buffer for arguments\n");
+		res = -ENODATA;
+		goto fail;
+	}
+fail:
+	kfree(cbt_info);
+
+	return res;
+}
+
+static int ioctl_tracker_read_cbt_map(unsigned long arg)
+{
+	struct blk_snap_tracker_read_cbt_bitmap karg;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to read CBT map: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	return tracker_read_cbt_bitmap(MKDEV(karg.dev_id.mj, karg.dev_id.mn),
+				       karg.offset, karg.length,
+				       (char __user *)karg.buff);
+}
+
+static int ioctl_tracker_mark_dirty_blocks(unsigned long arg)
+{
+	int ret = 0;
+	struct blk_snap_tracker_mark_dirty_blocks karg;
+	struct blk_snap_block_range *dirty_blocks_array;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to mark dirty blocks: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	dirty_blocks_array = kcalloc(
+		karg.count, sizeof(struct blk_snap_block_range), GFP_KERNEL);
+	if (!dirty_blocks_array)
+		return -ENOMEM;
+
+	if (copy_from_user(dirty_blocks_array, (void *)karg.dirty_blocks_array,
+			   karg.count * sizeof(struct blk_snap_block_range))) {
+		pr_err("Unable to mark dirty blocks: invalid user buffer\n");
+		ret = -ENODATA;
+	} else {
+		if (karg.dev_id.mj == snapimage_major())
+			ret = snapshot_mark_dirty_blocks(
+				MKDEV(karg.dev_id.mj, karg.dev_id.mn),
+				dirty_blocks_array, karg.count);
+		else
+			ret = tracker_mark_dirty_blocks(
+				MKDEV(karg.dev_id.mj, karg.dev_id.mn),
+				dirty_blocks_array, karg.count);
+	}
+
+	kfree(dirty_blocks_array);
+
+	return ret;
+}
+
+static int ioctl_snapshot_create(unsigned long arg)
+{
+	int ret;
+	struct blk_snap_snapshot_create karg;
+	struct blk_snap_dev *dev_id_array = NULL;
+	uuid_t new_id;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to create snapshot: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	dev_id_array =
+		kcalloc(karg.count, sizeof(struct blk_snap_dev), GFP_KERNEL);
+	if (dev_id_array == NULL) {
+		pr_err("Unable to create snapshot: too many devices %d\n",
+		       karg.count);
+		return -ENOMEM;
+	}
+
+	if (copy_from_user(dev_id_array, (void *)karg.dev_id_array,
+			   karg.count * sizeof(struct blk_snap_dev))) {
+		pr_err("Unable to create snapshot: invalid user buffer\n");
+		ret = -ENODATA;
+		goto out;
+	}
+
+	ret = snapshot_create(dev_id_array, karg.count, &new_id);
+	if (ret)
+		goto out;
+
+	export_uuid(karg.id.b, &new_id);
+	if (copy_to_user((void *)arg, &karg, sizeof(karg))) {
+		pr_err("Unable to create snapshot: invalid user buffer\n");
+		ret = -ENODATA;
+	}
+out:
+	kfree(dev_id_array);
+
+	return ret;
+}
+
+static int ioctl_snapshot_destroy(unsigned long arg)
+{
+	struct blk_snap_snapshot_destroy karg;
+	uuid_t id;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to destroy snapshot: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	import_uuid(&id, karg.id.b);
+	return snapshot_destroy(&id);
+}
+
+static int ioctl_snapshot_append_storage(unsigned long arg)
+{
+	struct blk_snap_snapshot_append_storage karg;
+	uuid_t id;
+
+	pr_debug("Append difference storage\n");
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to append difference storage: invalid user buffer\n");
+		return -EINVAL;
+	}
+
+	import_uuid(&id, karg.id.b);
+	return snapshot_append_storage(&id, karg.dev_id, karg.ranges,
+				       karg.count);
+}
+
+static int ioctl_snapshot_take(unsigned long arg)
+{
+	struct blk_snap_snapshot_take karg;
+	uuid_t id;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to take snapshot: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	import_uuid(&id, karg.id.b);
+	return snapshot_take(&id);
+}
+
+static int ioctl_snapshot_wait_event(unsigned long arg)
+{
+	int ret = 0;
+	struct blk_snap_snapshot_event *karg;
+	uuid_t id;
+	struct event *event;
+
+	karg = kzalloc(sizeof(struct blk_snap_snapshot_event), GFP_KERNEL);
+	if (!karg)
+		return -ENOMEM;
+
+	/* Copy only snapshot ID */
+	if (copy_from_user(&karg->id,
+			   &((struct blk_snap_snapshot_event *)arg)->id,
+			   sizeof(struct blk_snap_uuid))) {
+		pr_err("Unable to get snapshot event. Invalid user buffer\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	import_uuid(&id, karg->id.b);
+	event = snapshot_wait_event(&id, karg->timeout_ms);
+	if (IS_ERR(event)) {
+		ret = PTR_ERR(event);
+		goto out;
+	}
+
+	pr_debug("Received event=%lld code=%d data_size=%d\n", event->time,
+		 event->code, event->data_size);
+	karg->code = event->code;
+	karg->time_label = event->time;
+
+	if (event->data_size > sizeof(karg->data)) {
+		pr_err("Event size %d is too big\n", event->data_size);
+		ret = -ENOSPC;
+		/* If we can't copy all the data, we copy only part of it. */
+	}
+	memcpy(karg->data, event->data, event->data_size);
+	event_free(event);
+
+	if (copy_to_user((void *)arg, karg,
+			 sizeof(struct blk_snap_snapshot_event))) {
+		pr_err("Unable to get snapshot event. Invalid user buffer\n");
+		ret = -EINVAL;
+	}
+out:
+	kfree(karg);
+
+	return ret;
+}
+
+static int ioctl_snapshot_collect(unsigned long arg)
+{
+	int ret;
+	struct blk_snap_snapshot_collect karg;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to collect available snapshots: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	ret = snapshot_collect(&karg.count, karg.ids);
+
+	if (copy_to_user((void *)arg, &karg, sizeof(karg))) {
+		pr_err("Unable to collect available snapshots: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	return ret;
+}
+
+static int ioctl_snapshot_collect_images(unsigned long arg)
+{
+	int ret;
+	struct blk_snap_snapshot_collect_images karg;
+	uuid_t id;
+
+	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
+		pr_err("Unable to collect snapshot images: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	import_uuid(&id, karg.id.b);
+	ret = snapshot_collect_images(&id, karg.image_info_array,
+				      &karg.count);
+
+	if (copy_to_user((void *)arg, &karg, sizeof(karg))) {
+		pr_err("Unable to collect snapshot images: invalid user buffer\n");
+		return -ENODATA;
+	}
+
+	return ret;
+}
+
+static int (*const blk_snap_ioctl_table[])(unsigned long arg) = {
+	ioctl_version,
+	ioctl_tracker_remove,
+	ioctl_tracker_collect,
+	ioctl_tracker_read_cbt_map,
+	ioctl_tracker_mark_dirty_blocks,
+	ioctl_snapshot_create,
+	ioctl_snapshot_destroy,
+	ioctl_snapshot_append_storage,
+	ioctl_snapshot_take,
+	ioctl_snapshot_collect,
+	ioctl_snapshot_collect_images,
+	ioctl_snapshot_wait_event,
+};
+
+static_assert(
+	sizeof(blk_snap_ioctl_table) ==
+	((blk_snap_ioctl_snapshot_wait_event + 1) * sizeof(void *)),
+	"The size of table blk_snap_ioctl_table does not match the enum blk_snap_ioctl.");
+
+
+static long ctrl_unlocked_ioctl(struct file *filp, unsigned int cmd,
+				unsigned long arg)
+{
+	int nr = _IOC_NR(cmd);
+
+	if (nr > (sizeof(blk_snap_ioctl_table) / sizeof(void *)))
+		return -ENOTTY;
+
+	if (!blk_snap_ioctl_table[nr])
+		return -ENOTTY;
+
+	return blk_snap_ioctl_table[nr](arg);
+}
diff --git a/drivers/block/blksnap/ctrl.h b/drivers/block/blksnap/ctrl.h
new file mode 100644
index 000000000000..ade3f1cf57e9
--- /dev/null
+++ b/drivers/block/blksnap/ctrl.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __BLK_SNAP_CTRL_H
+#define __BLK_SNAP_CTRL_H
+
+int get_blk_snap_major(void);
+
+int ctrl_init(void);
+void ctrl_done(void);
+#endif /* __BLK_SNAP_CTRL_H */
-- 
2.20.1

On Fri, Dec 09, 2022 at 03:23:16PM +0100, Sergei Shtepa wrote:
> +static int ioctl_tracker_mark_dirty_blocks(unsigned long arg)
> +{
> +	int ret = 0;
> +	struct blk_snap_tracker_mark_dirty_blocks karg;
> +	struct blk_snap_block_range *dirty_blocks_array;
> +
> +	if (copy_from_user(&karg, (void *)arg, sizeof(karg))) {
> +		pr_err("Unable to mark dirty blocks: invalid user buffer\n");
> +		return -ENODATA;
> +	}
> +
> +	dirty_blocks_array = kcalloc(
> +		karg.count, sizeof(struct blk_snap_block_range), GFP_KERNEL);
> +	if (!dirty_blocks_array)
> +		return -ENOMEM;
> +
> +	if (copy_from_user(dirty_blocks_array, (void *)karg.dirty_blocks_array,
> +			   karg.count * sizeof(struct blk_snap_block_range))) {
> +		pr_err("Unable to mark dirty blocks: invalid user buffer\n");
> +		ret = -ENODATA;

Minor nit:
The following could be done to keep it consistent with other functions:

	if (copy_from_user(dirty_blocks_array, (void *)karg.dirty_blocks_array,
			   karg.count * sizeof(struct blk_snap_block_range))) {
		pr_err("Unable to mark dirty blocks: invalid user buffer\n");
		ret = -ENODATA;
		goto out;
	}

	if (karg.dev_id.mj == snapimage_major())
		ret = snapshot_mark_dirty_blocks(
			MKDEV(karg.dev_id.mj, karg.dev_id.mn),
			dirty_blocks_array, karg.count);
	else
		ret = tracker_mark_dirty_blocks(
			MKDEV(karg.dev_id.mj, karg.dev_id.mn),
			dirty_blocks_array, karg.count);
out:
	kfree(dirty_blocks_array);

	return ret;
}


> +	} else {
> +		if (karg.dev_id.mj == snapimage_major())
> +			ret = snapshot_mark_dirty_blocks(
> +				MKDEV(karg.dev_id.mj, karg.dev_id.mn),
> +				dirty_blocks_array, karg.count);
> +		else
> +			ret = tracker_mark_dirty_blocks(
> +				MKDEV(karg.dev_id.mj, karg.dev_id.mn),
> +				dirty_blocks_array, karg.count);
> +	}
> +
> +	kfree(dirty_blocks_array);
> +
> +	return ret;
> +}
> +
-- 
Pankaj Raghav

> +	ret = register_chrdev(0, THIS_MODULE->name, &ctrl_fops);

This crashed when blksnap is built into the kernel because THIS_MODULE
is NULL for that case.

But I think most of this boilerplate can be removed - just use a misc
device and use /proc/misc to find the major from userspace if anything
cares, but nothing should as the misc devices already create the
node through udev.  I.e.g:

diff --git a/drivers/block/blksnap/Makefile b/drivers/block/blksnap/Makefile
index b196b17f9d9d97..cbcac12cc61d59 100644
--- a/drivers/block/blksnap/Makefile
+++ b/drivers/block/blksnap/Makefile
@@ -12,7 +12,6 @@ blksnap-y := 		\
 	main.o		\
 	snapimage.o	\
 	snapshot.o	\
-	sysfs.o		\
 	tracker.o
 
 obj-$(CONFIG_BLK_SNAP)	 += blksnap.o
diff --git a/drivers/block/blksnap/ctrl.c b/drivers/block/blksnap/ctrl.c
index 990ffb004db3f9..d1a5e3a13a19be 100644
--- a/drivers/block/blksnap/ctrl.c
+++ b/drivers/block/blksnap/ctrl.c
@@ -5,6 +5,7 @@
 #include <linux/poll.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/miscdevice.h>
 #include <uapi/linux/blksnap.h>
 #include "ctrl.h"
 #include "params.h"
@@ -16,16 +17,6 @@
 static_assert(sizeof(uuid_t) == sizeof(struct blk_snap_uuid),
 	"Invalid size of struct blk_snap_uuid or uuid_t.");
 
-static int blk_snap_major;
-
-static long ctrl_unlocked_ioctl(struct file *filp, unsigned int cmd,
-				unsigned long arg);
-
-static const struct file_operations ctrl_fops = {
-	.owner = THIS_MODULE,
-	.unlocked_ioctl = ctrl_unlocked_ioctl,
-};
-
 static const struct blk_snap_version version = {
 	.major = VERSION_MAJOR,
 	.minor = VERSION_MINOR,
@@ -33,34 +24,6 @@ static const struct blk_snap_version version = {
 	.build = VERSION_BUILD,
 };
 
-int get_blk_snap_major(void)
-{
-	return blk_snap_major;
-}
-
-int ctrl_init(void)
-{
-	int ret;
-
-	ret = register_chrdev(0, THIS_MODULE->name, &ctrl_fops);
-	if (ret < 0) {
-		pr_err("Failed to register a character device. errno=%d\n",
-		       abs(blk_snap_major));
-		return ret;
-	}
-
-	blk_snap_major = ret;
-	pr_info("Register control device [%d:0].\n", blk_snap_major);
-	return 0;
-}
-
-void ctrl_done(void)
-{
-	pr_info("Unregister control device\n");
-
-	unregister_chrdev(blk_snap_major, THIS_MODULE->name);
-}
-
 static int ioctl_version(unsigned long arg)
 {
 	if (copy_to_user((void *)arg, &version, sizeof(version))) {
@@ -408,3 +371,24 @@ static long ctrl_unlocked_ioctl(struct file *filp, unsigned int cmd,
 
 	return blk_snap_ioctl_table[nr](arg);
 }
+
+static const struct file_operations blksnap_ctrl_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= ctrl_unlocked_ioctl,
+};
+
+static struct miscdevice blksnap_ctrl_misc = {
+	.minor		= MISC_DYNAMIC_MINOR,
+	.name		= "blksnap-control",
+	.fops		= &blksnap_ctrl_fops,
+};
+
+int ctrl_init(void)
+{
+	return misc_register(&blksnap_ctrl_misc);
+}
+
+void ctrl_done(void)
+{
+	misc_deregister(&blksnap_ctrl_misc);
+}
diff --git a/drivers/block/blksnap/ctrl.h b/drivers/block/blksnap/ctrl.h
index ade3f1cf57e90c..88f4b05296e575 100644
--- a/drivers/block/blksnap/ctrl.h
+++ b/drivers/block/blksnap/ctrl.h
@@ -2,8 +2,6 @@
 #ifndef __BLK_SNAP_CTRL_H
 #define __BLK_SNAP_CTRL_H
 
-int get_blk_snap_major(void);
-
 int ctrl_init(void);
 void ctrl_done(void);
 #endif /* __BLK_SNAP_CTRL_H */
diff --git a/drivers/block/blksnap/main.c b/drivers/block/blksnap/main.c
index a7939efc6497b9..f8b6f5c406ed7c 100644
--- a/drivers/block/blksnap/main.c
+++ b/drivers/block/blksnap/main.c
@@ -6,7 +6,6 @@
 #include "version.h"
 #include "params.h"
 #include "ctrl.h"
-#include "sysfs.h"
 #include "snapimage.h"
 #include "snapshot.h"
 #include "tracker.h"
@@ -44,8 +43,6 @@ static int __init blk_snap_init(void)
 	result = ctrl_init();
 	if (result)
 		return result;
-
-	result = sysfs_initialize();
 	return result;
 }
 
@@ -53,7 +50,6 @@ static void __exit blk_snap_exit(void)
 {
 	pr_info("Unloading module\n");
 
-	sysfs_finalize();
 	ctrl_done();
 
 	diff_io_done();
diff --git a/drivers/block/blksnap/sysfs.c b/drivers/block/blksnap/sysfs.c
deleted file mode 100644
index 6f53c4217d6c7b..00000000000000
--- a/drivers/block/blksnap/sysfs.c
+++ /dev/null
@@ -1,80 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#define pr_fmt(fmt) KBUILD_MODNAME "-sysfs: " fmt
-
-#include <linux/module.h>
-#include <linux/blkdev.h>
-#include <linux/sysfs.h>
-#include <linux/device.h>
-#include <uapi/linux/blksnap.h>
-#include "sysfs.h"
-#include "ctrl.h"
-
-static ssize_t major_show(struct class *class, struct class_attribute *attr,
-			  char *buf)
-{
-	sprintf(buf, "%d", get_blk_snap_major());
-	return strlen(buf);
-}
-
-/* Declare class_attr_major */
-CLASS_ATTR_RO(major);
-
-static struct class *blk_snap_class;
-
-static struct device *blk_snap_device;
-
-int sysfs_initialize(void)
-{
-	struct device *dev;
-	int res;
-
-	blk_snap_class = class_create(THIS_MODULE, THIS_MODULE->name);
-	if (IS_ERR(blk_snap_class)) {
-		res = PTR_ERR(blk_snap_class);
-
-		pr_err("Bad class create. errno=%d\n", abs(res));
-		return res;
-	}
-
-	pr_info("Create 'major' sysfs attribute\n");
-	res = class_create_file(blk_snap_class, &class_attr_major);
-	if (res) {
-		pr_err("Failed to create 'major' sysfs file\n");
-
-		class_destroy(blk_snap_class);
-		blk_snap_class = NULL;
-		return res;
-	}
-
-	dev = device_create(blk_snap_class, NULL,
-			    MKDEV(get_blk_snap_major(), 0), NULL,
-			    THIS_MODULE->name);
-	if (IS_ERR(dev)) {
-		res = PTR_ERR(dev);
-		pr_err("Failed to create device, errno=%d\n", abs(res));
-
-		class_remove_file(blk_snap_class, &class_attr_major);
-		class_destroy(blk_snap_class);
-		blk_snap_class = NULL;
-		return res;
-	}
-
-	blk_snap_device = dev;
-	return res;
-}
-
-void sysfs_finalize(void)
-{
-	pr_info("Cleanup sysfs\n");
-
-	if (blk_snap_device) {
-		device_unregister(blk_snap_device);
-		blk_snap_device = NULL;
-	}
-
-	if (blk_snap_class != NULL) {
-		class_remove_file(blk_snap_class, &class_attr_major);
-		class_destroy(blk_snap_class);
-		blk_snap_class = NULL;
-	}
-}
diff --git a/drivers/block/blksnap/sysfs.h b/drivers/block/blksnap/sysfs.h
deleted file mode 100644
index 5fc200d3678964..00000000000000
--- a/drivers/block/blksnap/sysfs.h
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __BLK_SNAP_SYSFS_H
-#define __BLK_SNAP_SYSFS_H
-
-int sysfs_initialize(void);
-void sysfs_finalize(void);
-#endif /* __BLK_SNAP_SYSFS_H */