splice: export do_tee()

export do_tee() for use in io_uring

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/splice.h

@@ -82,6 +82,9 @@ extern long do_splice(struct file *in, loff_t __user *off_in,
 		      struct file *out, loff_t __user *off_out,
 		      size_t len, unsigned int flags);
 
+extern long do_tee(struct file *in, struct file *out, size_t len,
+		   unsigned int flags);
+
 /*
  * for dynamic pipe sizing
  */