CIFS: SMBD: Introduce kernel config option CONFIG_CIFS_SMB_DIRECT

Build SMB Direct code when this option is set.
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>

fs/cifs/Kconfig

@@ -196,6 +196,14 @@ config CIFS_SMB311
 	  This dialect includes improved security negotiation features.
 	  If unsure, say N
 
+config CIFS_SMB_DIRECT
+	bool "SMB Direct support (Experimental)"
+	depends on CIFS && INFINIBAND
+	help
+	  Enables SMB Direct experimental support for SMB 3.0, 3.02 and 3.1.1.
+	  SMB Direct allows transferring SMB packets over RDMA. If unsure,
+	  say N.
+
 config CIFS_FSCACHE
 	  bool "Provide CIFS client caching support"
 	  depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y