diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index b120e85aa7b9..2f442d9f0cf9 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -267,7 +267,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
 {
 	struct kernfs_open_file *of = kernfs_of(file);
 	const struct kernfs_ops *ops;
-	size_t len;
+	ssize_t len;
 	char *buf;
 
 	if (of->atomic_write_len) {