drbd: Define the size of res_opts->cpu_mask in a single place

Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index de7d74a..6f60136 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -382,4 +382,6 @@
 #define DRBD_MD_INDEX_FLEX_EXT -2
 #define DRBD_MD_INDEX_FLEX_INT -3
 
+#define DRBD_CPU_MASK_SIZE 32
+
 #endif
diff --git a/include/linux/drbd_genl.h b/include/linux/drbd_genl.h
index b14a2e8..4193f5f 100644
--- a/include/linux/drbd_genl.h
+++ b/include/linux/drbd_genl.h
@@ -135,7 +135,7 @@
 )
 
 GENL_struct(DRBD_NLA_RESOURCE_OPTS, 4, res_opts,
-	__str_field_def(1,	DRBD_GENLA_F_MANDATORY,	cpu_mask,       32)
+	__str_field_def(1,	DRBD_GENLA_F_MANDATORY,	cpu_mask,       DRBD_CPU_MASK_SIZE)
 	__u32_field_def(2,	DRBD_GENLA_F_MANDATORY,	on_no_data, DRBD_ON_NO_DATA_DEF)
 )