--- zzzz-none-000/linux-2.6.39.4/fs/splice.c	2011-08-03 19:43:28.000000000 +0000
+++ puma6-atom-6490-729/linux-2.6.39.4/fs/splice.c	2021-11-10 13:38:17.000000000 +0000
@@ -562,7 +562,7 @@
 	return res;
 }
 
-static ssize_t kernel_write(struct file *file, const char *buf, size_t count,
+ssize_t kernel_write(struct file *file, const char *buf, size_t count,
 			    loff_t pos)
 {
 	mm_segment_t old_fs;
@@ -571,11 +571,12 @@
 	old_fs = get_fs();
 	set_fs(get_ds());
 	/* The cast to a user pointer is valid due to the set_fs() */
-	res = vfs_write(file, (const char __user *)buf, count, &pos);
+	res = vfs_write(file, (__force const char __user *)buf, count, &pos);
 	set_fs(old_fs);
 
 	return res;
 }
+EXPORT_SYMBOL(kernel_write);
 
 ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
 				 struct pipe_inode_info *pipe, size_t len,