net: convert lists of macros to enumerations

Use enumerations to replace macros for simpler preprocessing. Map numeric values to enumerators. Where required, prepend the list with an additional enumerator to accommodate the rest.

---
 include/linux/net.h      | 15 +++++++++------
 include/uapi/linux/net.h | 43 +++++++++++++++++++++++--------------------
 2 files changed, 32 insertions(+), 26 deletions(-)

index 4f27575..84444bb 100644
@@ -32,12 +32,15 @@ struct inode;
 struct file;
 struct net;
 
-#define SOCK_ASYNC_NOSPACE	0
-#define SOCK_ASYNC_WAITDATA	1
-#define SOCK_NOSPACE		2
-#define SOCK_PASSCRED		3
-#define SOCK_PASSSEC		4
-#define SOCK_EXTERNALLY_ALLOCATED 5
+/* Bit value for {set,clear,test{,_and_clear}}_bit() */
+enum {
+	SOCK_ASYNC_NOSPACE,		/* 0 */
+	SOCK_ASYNC_WAITDATA,		/* 1 */
+	SOCK_NOSPACE,			/* 2 */
+	SOCK_PASSCRED,			/* 3 */
+	SOCK_PASSSEC,			/* 4 */
+	SOCK_EXTERNALLY_ALLOCATED,	/* 5 */
+};
 
 #ifndef ARCH_HAS_SOCKET_TYPES
 /**

Clean up the unnecessary assignment of the first enumerator to zero.

---
 include/uapi/linux/net.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 9136b54..9177fd3 100644
@@ -48,7 +48,7 @@ enum {
 };
 
 typedef enum {
-	SS_FREE = 0,			/* not allocated		*/
+	SS_FREE,			/* not allocated		*/
 	SS_UNCONNECTED,			/* unconnected to any socket	*/
 	SS_CONNECTING,			/* in process of connecting	*/
 	SS_CONNECTED,			/* connected to socket		*/

Converting the network based header files is easy and safe as long as you test it. Not sure if it is worth the effort.

But changing the uapi exported header risks breaking applications that were doing:

#ifdef SIOCXXXX
do some code to enable that
#endif

Since enum values don't show up in the CPP namespace.

From: Stephen Hemminger <[email protected]>
Date: Mon, 24 Jun 2013 08:14:14 -0700

Agreed, these patches aren't to be considered seriously. Too much potential breakage, and even without that risk I see pretty much zero value to these changes.