RDMA/uverbs: Export XRC domains to user space

Allow user space to create XRC domains.  Because XRCDs are expected to
be shared among multiple processes, we use inodes to identify an XRCD.

Based on patches by Jack Morgenstein <jackm@dev.mellanox.co.il>

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/include/rdma/ib_user_verbs.h b/include/rdma/ib_user_verbs.h
index fe5b051..b5cb63f 100644
--- a/include/rdma/ib_user_verbs.h
+++ b/include/rdma/ib_user_verbs.h
@@ -81,7 +81,9 @@
 	IB_USER_VERBS_CMD_MODIFY_SRQ,
 	IB_USER_VERBS_CMD_QUERY_SRQ,
 	IB_USER_VERBS_CMD_DESTROY_SRQ,
-	IB_USER_VERBS_CMD_POST_SRQ_RECV
+	IB_USER_VERBS_CMD_POST_SRQ_RECV,
+	IB_USER_VERBS_CMD_OPEN_XRCD,
+	IB_USER_VERBS_CMD_CLOSE_XRCD
 };
 
 /*
@@ -222,6 +224,21 @@
 	__u32 pd_handle;
 };
 
+struct ib_uverbs_open_xrcd {
+	__u64 response;
+	__u32 fd;
+	__u32 oflags;
+	__u64 driver_data[0];
+};
+
+struct ib_uverbs_open_xrcd_resp {
+	__u32 xrcd_handle;
+};
+
+struct ib_uverbs_close_xrcd {
+	__u32 xrcd_handle;
+};
+
 struct ib_uverbs_reg_mr {
 	__u64 response;
 	__u64 start;