diff --git a/sys/compat/linuxkpi/common/include/linux/seq_file.h b/sys/compat/linuxkpi/common/include/linux/seq_file.h
index 83b25a45c1d0..d8b327f59538 100644
--- a/sys/compat/linuxkpi/common/include/linux/seq_file.h
+++ b/sys/compat/linuxkpi/common/include/linux/seq_file.h
@@ -1,93 +1,94 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause
  *
  * Copyright (c) 2016-2018, Matthew Macy <mmacy@freebsd.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #ifndef _LINUXKPI_LINUX_SEQ_FILE_H_
 #define _LINUXKPI_LINUX_SEQ_FILE_H_
 
 #include <linux/types.h>
 #include <linux/fs.h>
+#include <linux/string_helpers.h>
 
 #undef file
 #define inode vnode
 
 MALLOC_DECLARE(M_LSEQ);
 
 #define	DEFINE_SHOW_ATTRIBUTE(__name)					\
 static int __name ## _open(struct inode *inode, struct linux_file *file)	\
 {									\
 	return single_open(file, __name ## _show, inode->i_private);	\
 }									\
 									\
 static const struct file_operations __name ## _fops = {			\
 	.owner		= THIS_MODULE,					\
 	.open		= __name ## _open,				\
 	.read		= seq_read,					\
 	.llseek		= seq_lseek,					\
 	.release	= single_release,				\
 }
 
 struct seq_file {
 	struct sbuf *buf;
 	size_t size;
 	const struct seq_operations *op;
 	const struct linux_file *file;
 	void *private;
 };
 
 struct seq_operations {
 	void * (*start) (struct seq_file *m, off_t *pos);
 	void (*stop) (struct seq_file *m, void *v);
 	void * (*next) (struct seq_file *m, void *v, off_t *pos);
 	int (*show) (struct seq_file *m, void *v);
 };
 
 ssize_t seq_read(struct linux_file *, char *, size_t, off_t *);
 int seq_write(struct seq_file *seq, const void *data, size_t len);
 void seq_putc(struct seq_file *m, char c);
 void seq_puts(struct seq_file *m, const char *str);
 bool seq_has_overflowed(struct seq_file *m);
 
 void *__seq_open_private(struct linux_file *, const struct seq_operations *, int);
 int seq_release_private(struct inode *, struct linux_file *);
 
 int seq_open(struct linux_file *f, const struct seq_operations *op);
 int seq_release(struct inode *inode, struct linux_file *file);
 
 off_t seq_lseek(struct linux_file *file, off_t offset, int whence);
 int single_open(struct linux_file *, int (*)(struct seq_file *, void *), void *);
 int single_open_size(struct linux_file *, int (*)(struct seq_file *, void *), void *, size_t);
 int single_release(struct inode *, struct linux_file *);
 
 void lkpi_seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
 void lkpi_seq_printf(struct seq_file *m, const char *fmt, ...);
 
 #define	seq_vprintf(...)	lkpi_seq_vprintf(__VA_ARGS__)
 #define	seq_printf(...)		lkpi_seq_printf(__VA_ARGS__)
 
 #define	file			linux_file
 
 #endif	/* _LINUXKPI_LINUX_SEQ_FILE_H_ */