Add support for async IO verification offload

This adds support for setting up a number of IO verification offload
threads, instead of doing the offload inline. An option for controlling
the CPU affinity of those threads are always added.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/verify.h b/verify.h
index 76d256d..50c8e43 100644
--- a/verify.h
+++ b/verify.h
@@ -64,5 +64,12 @@
 extern void populate_verify_io_u(struct thread_data *, struct io_u *);
 extern int __must_check get_next_verify(struct thread_data *td, struct io_u *);
 extern int __must_check verify_io_u(struct thread_data *, struct io_u *);
+extern int verify_io_u_async(struct thread_data *, struct io_u *);
+
+/*
+ * Async verify offload
+ */
+extern int verify_async_init(struct thread_data *);
+extern void verify_async_exit(struct thread_data *);
 
 #endif