: Provide central source file and debug facility

[TFRC]: Provide central source file and debug facility

This patch changes the tfrc_lib module in the following manner:

(1) a dedicated tfrc_module source file (this is later populated

     with TX/RX hist and LI Database routines);

(2) a dedicated tfrc_pr_debug macro with toggle switch `tfrc_debug'.

The first serves to make the source code structure clearer, since module initialisation and module parameter statements are currently spread over loss_interval.c and packet_history.c (which are part of the tfrc_lib).

There is no functional change in this patch: but subsequent patches will contribute module initialisation/cleanup routines (left open for now).

Point (2) provides a functionality which is available in all other DCCP modules already: module debugging is enabled via a Kconfig option, in the running code, debugging output can be toggled via the module parameter `tfrc_debug'. So far, one had to resort to dccp_pr_debug for this, but it is not a good idea since it destroys the logical module separation and makes tfrc_lib debugging dependent on dccp main-module debugging flags.

NB: TFRC debugging is enabled via Kconfig dependency on CCID3 debug,
since CCID3 is currently the only `customer' of the TFRC library.

---
 net/dccp/ccids/Kconfig              |   12 ++++++++----
 net/dccp/ccids/lib/Makefile         |    3 ++-
 net/dccp/ccids/lib/packet_history.c |    7 -------
 net/dccp/ccids/lib/packet_history.h |    3 +--
 net/dccp/ccids/lib/tfrc.h           |    8 ++++++++
 net/dccp/ccids/lib/tfrc_module.c    |   31 +++++++++++++++++++++++++++++++
 6 files changed, 50 insertions(+), 14 deletions(-)

@@ -15,6 +15,14 @@
  */
 #include <linux/types.h>
 #include <asm/div64.h>
+#include "../../dccp.h"
+
+#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
+extern int tfrc_debug;
+#define tfrc_pr_debug(format, a...)	DCCP_PR_DEBUG(tfrc_debug, format, ##a)
+#else
+#define tfrc_pr_debug(format, a...)
+#endif
 
 /* integer-arithmetic divisions of type (a * 1000000)/b */
 static inline u64 scaled_div(u64 a, u32 b)

@@ -1,3 +1,4 @@
 obj-$(CONFIG_IP_DCCP_TFRC_LIB) += dccp_tfrc_lib.o
 
-dccp_tfrc_lib-y := loss_interval.o packet_history.o tfrc_equation.o
+dccp_tfrc_lib-y := tfrc_module.o    tfrc_equation.o \
+                   packet_history.o loss_interval.o

@@ -0,0 +1,31 @@
+/*
+ * TFRC: main module holding the pieces of the TFRC library together
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include "tfrc.h"
+
+static int __init tfrc_module_init(void)
+{
+	int rc = 0;
+
+	return rc;
+}
+
+static void __exit tfrc_module_exit(void)
+{
+}
+
+module_init(tfrc_module_init);
+module_exit(tfrc_module_exit);
+
+#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
+int tfrc_debug;
+module_param(tfrc_debug, bool, 0444);
+MODULE_PARM_DESC(tfrc_debug, "Enable debug messages");
+#endif
+
+MODULE_AUTHOR("Ian McDonald <[email protected]>, "
+	      "Arnaldo Carvalho de Melo <[email protected]>");
+MODULE_DESCRIPTION("DCCP TFRC library");
+MODULE_LICENSE("GPL");

@@ -34,7 +34,6 @@
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <linux/module.h>
 #include <linux/string.h>
 #include "packet_history.h"
 

@@ -296,9 +295,3 @@ void dccp_rx_hist_purge(struct dccp_rx_h
 }
 
 EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
-
-
-MODULE_AUTHOR("Ian McDonald <[email protected]>, "
-	      "Arnaldo Carvalho de Melo <[email protected]>");
-MODULE_DESCRIPTION("DCCP TFRC library");
-MODULE_LICENSE("GPL");

@@ -40,8 +40,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/time.h>
-
-#include "../../dccp.h"
+#include "tfrc.h"
 
 /* Number of later packets received before one is considered lost */
 #define TFRC_RECV_NUM_LATE_LOSS	 3

@@ -74,10 +74,6 @@ config IP_DCCP_CCID3
 
 	  If in doubt, say M.
 
-config IP_DCCP_TFRC_LIB
-	depends on IP_DCCP_CCID3
-	def_tristate IP_DCCP_CCID3
-
 config IP_DCCP_CCID3_DEBUG
 	  bool "CCID3 debugging messages"
 	  depends on IP_DCCP_CCID3

@@ -121,5 +117,13 @@ config IP_DCCP_CCID3_RTO
 	    is serious network congestion: experimenting with larger values should
 	    therefore not be performed on WANs.
 
+# The TFRC Library: currently only has CCID 3 as customer
+config IP_DCCP_TFRC_LIB
+	depends on IP_DCCP_CCID3
+	def_tristate IP_DCCP_CCID3
+
+config IP_DCCP_TFRC_DEBUG
+	bool
+	default y if IP_DCCP_CCID3_DEBUG
 
 endmenu

Do you intend to get rid of either of these or are we just increasing number of files?

I'll signoff on it trusting that the changes to come make it worthwhile.

Web: http://wand.net.nz/~iam4/
Blog: http://iansblog.jandi.co.nz
WAND Network Research Group

Ian McDonald wrote:

|  > The first serves to make the source code structure clearer, since module
|  > initialisation and module parameter statements are currently spread over
|  > loss_interval.c and packet_history.c (which are part of the tfrc_lib).
|  
|  Do you intend to get rid of either of these or are we just increasing
|  number of files?

By no means - the organisation of the source files is fine: packet_history.c does one thing and not another, and so do tfrc_equation.c and loss_interval.c.

The point is that each of these files does something specific.

The added file is therefore more of a binder: aggregating those files which serve only a specific purpose.

During the course of the the next patches, initialisation and cleanup routines will follow.

Further module parameters and module documentation can also be added to this file.