vfs: export do_splice_direct() to modules

Export do_splice_direct() to modules.  Needed by overlay filesystem.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
(cherry picked from commit 1c118596a7682912106c80007102ce0184c77780)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
diff --git a/fs/internal.h b/fs/internal.h
index 4657424..873cdf5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -135,12 +135,6 @@
 extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
 
 /*
- * splice.c
- */
-extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
-		loff_t *opos, size_t len, unsigned int flags);
-
-/*
  * pipe.c
  */
 extern const struct file_operations pipefifo_fops;
diff --git a/fs/splice.c b/fs/splice.c
index 12028fa..ffb92b9 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1327,6 +1327,7 @@
 
 	return ret;
 }
+EXPORT_SYMBOL(do_splice_direct);
 
 static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
 			       struct pipe_inode_info *opipe,