staging: lustre: debug: initialize debug_msg_data if needed

initialize the libcfs_debug_msg_data only if needed
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-1408
Reviewed-on: http://review.whamcloud.com/8338Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/cl_object.h

@@ -1041,9 +1041,8 @@ struct cl_page_operations {
  */
 #define CL_PAGE_DEBUG(mask, env, page, format, ...)		     \
 do {								    \
-	LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		\
-									\
 	if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) {		   \
+		LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);	\
 		cl_page_print(env, &msgdata, lu_cdebug_printer, page);  \
 		CDEBUG(mask, format, ## __VA_ARGS__);		  \
 	}							       \
@@ -1054,9 +1053,8 @@ do {								    \
  */
 #define CL_PAGE_HEADER(mask, env, page, format, ...)			  \
 do {									  \
-	LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		      \
-									      \
 	if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) {			 \
+		LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		\
 		cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
 		CDEBUG(mask, format, ## __VA_ARGS__);			\
 	}								     \

drivers/staging/lustre/lustre/include/lu_object.h

@@ -780,9 +780,8 @@ int lu_cdebug_printer(const struct lu_env *env,
  */
 #define LU_OBJECT_DEBUG(mask, env, object, format, ...)		   \
 do {								      \
-	LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		  \
-									  \
 	if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) {		     \
+		LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		\
 		lu_object_print(env, &msgdata, lu_cdebug_printer, object);\
 		CDEBUG(mask, format, ## __VA_ARGS__);		    \
 	}								 \
@@ -793,9 +792,8 @@ do {								      \
  */
 #define LU_OBJECT_HEADER(mask, env, object, format, ...)		\
 do {								    \
-	LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		\
-									\
 	if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) {		   \
+		LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL);		\
 		lu_object_header_print(env, &msgdata, lu_cdebug_printer,\
 				       (object)->lo_header);	    \
 		lu_cdebug_printer(env, &msgdata, "\n");		 \