Name: Automagic Proc Entry Creation
Author: Rusty Russell
Status: Tested on 2.5.71-bk2

Use the module_init_exit to write a "module_proc_net" macro, as an example.

Index: linux-2.6.10-rc2-bk11-Module/net/ipv4/netfilter/ip_tables.c
===================================================================
--- linux-2.6.10-rc2-bk11-Module.orig/net/ipv4/netfilter/ip_tables.c	2004-11-29 07:48:58.000000000 +1100
+++ linux-2.6.10-rc2-bk11-Module/net/ipv4/netfilter/ip_tables.c	2004-11-29 17:35:26.504257608 +1100
@@ -1740,7 +1740,6 @@
 	.checkentry	= &icmp_checkentry,
 };
 
-#ifdef CONFIG_PROC_FS
 static inline int print_name(const char *i,
 			     off_t start_offset, char *buffer, int length,
 			     off_t *pos, unsigned int *count)
@@ -1820,12 +1819,9 @@
 	return pos;
 }
 
-static struct { char *name; get_info_t *get_info; } ipt_proc_entry[] =
-{ { "ip_tables_names", ipt_get_tables },
-  { "ip_tables_targets", ipt_get_targets },
-  { "ip_tables_matches", ipt_get_matches },
-  { NULL, NULL} };
-#endif /*CONFIG_PROC_FS*/
+module_proc_net("ip_tables_names", ipt_get_tables);
+module_proc_net("ip_tables_targets", ipt_get_targets);
+module_proc_net("ip_tables_matches", ipt_get_matches);
 
 static int __init init(void)
 {
@@ -1847,25 +1843,6 @@
 		return ret;
 	}
 
-#ifdef CONFIG_PROC_FS
-	{
-	struct proc_dir_entry *proc;
-	int i;
-
-	for (i = 0; ipt_proc_entry[i].name; i++) {
-		proc = proc_net_create(ipt_proc_entry[i].name, 0,
-				       ipt_proc_entry[i].get_info);
-		if (!proc) {
-			while (--i >= 0)
-				proc_net_remove(ipt_proc_entry[i].name);
-			nf_unregister_sockopt(&ipt_sockopts);
-			return -ENOMEM;
-		}
-		proc->owner = THIS_MODULE;
-	}
-	}
-#endif
-
 	printk("ip_tables: (C) 2000-2002 Netfilter core team\n");
 	return 0;
 }
@@ -1873,13 +1850,6 @@
 static void __exit fini(void)
 {
 	nf_unregister_sockopt(&ipt_sockopts);
-#ifdef CONFIG_PROC_FS
-	{
-	int i;
-	for (i = 0; ipt_proc_entry[i].name; i++)
-		proc_net_remove(ipt_proc_entry[i].name);
-	}
-#endif
 }
 
 EXPORT_SYMBOL(ipt_register_table);
Index: linux-2.6.10-rc2-bk11-Module/include/linux/proc_fs.h
===================================================================
--- linux-2.6.10-rc2-bk11-Module.orig/include/linux/proc_fs.h	2004-11-16 15:30:07.000000000 +1100
+++ linux-2.6.10-rc2-bk11-Module/include/linux/proc_fs.h	2004-11-29 17:24:09.903116616 +1100
@@ -4,6 +4,7 @@
 #include <linux/config.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
+#include <linux/init.h>
 #include <asm/atomic.h>
 
 /*
@@ -189,6 +190,20 @@
 	remove_proc_entry(name,proc_net);
 }
 
+#define module_proc_net(name, fn)					     \
+static int __cat(_proc_net_init,fn)(void)				     \
+{									     \
+	struct proc_dir_entry *proc = proc_net_create(name, 0, fn);	     \
+	if (!proc)							     \
+		return -EINVAL;						     \
+	proc->owner = THIS_MODULE;					     \
+	return 0;							     \
+}									     \
+static void __cat(_proc_net_exit,fn)(void)				     \
+{									     \
+	proc_net_remove(name);						     \
+}									     \
+module_init_exit(__cat(_proc_net_init,fn), __cat(_proc_net_exit,fn))
 #else
 
 #define proc_root_driver NULL
@@ -225,6 +240,10 @@
 
 extern struct proc_dir_entry proc_root;
 
+/* Check type and stop gcc from complaining about unused function, but
+ * allow gcc 3.3+ to discard it. */
+#define module_proc_net(name, fn)     \
+static inline get_info_t *__unique_id(test_fntype)(void) { return fn; }
 #endif /* CONFIG_PROC_FS */
 
 #if !defined(CONFIG_PROC_KCORE)
Index: linux-2.6.10-rc2-bk11-Module/net/ipv4/netfilter/arp_tables.c
===================================================================
--- linux-2.6.10-rc2-bk11-Module.orig/net/ipv4/netfilter/arp_tables.c	2004-11-16 15:30:12.000000000 +1100
+++ linux-2.6.10-rc2-bk11-Module/net/ipv4/netfilter/arp_tables.c	2004-11-29 17:24:09.904116464 +1100
@@ -1243,7 +1243,6 @@
 	.get		= do_arpt_get_ctl,
 };
 
-#ifdef CONFIG_PROC_FS
 static inline int print_name(const struct arpt_table *t,
 			     off_t start_offset, char *buffer, int length,
 			     off_t *pos, unsigned int *count)
@@ -1278,7 +1277,8 @@
 	*start=(char *)((unsigned long)count-offset);
 	return pos;
 }
-#endif /*CONFIG_PROC_FS*/
+
+module_proc_net("arp_tables_names", arpt_get_tables);
 
 static int __init init(void)
 {
@@ -1297,19 +1297,6 @@
 		return ret;
 	}
 
-#ifdef CONFIG_PROC_FS
-	{
-		struct proc_dir_entry *proc;
-
-		proc = proc_net_create("arp_tables_names", 0, arpt_get_tables);
-		if (!proc) {
-			nf_unregister_sockopt(&arpt_sockopts);
-			return -ENOMEM;
-		}
-		proc->owner = THIS_MODULE;
-	}
-#endif
-
 	printk("arp_tables: (C) 2002 David S. Miller\n");
 	return 0;
 }