sysctl: Remove check for sentinel element in ctl_table arrays

Use ARRAY_SIZE exclusively by removing the check to ->procname in the
stopping criteria of the loops traversing ctl_table arrays. This commit
finalizes the removal of the sentinel elements at the end of ctl_table
arrays which reduces the build time size and run time memory bloat by
~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove the entry->procname evaluation from the for loop stopping
criteria in sysctl and sysctl_net.

Signed-off-by: Joel Granados <j.granados@samsung.com>

Author: Joelgranados

fs/proc/proc_sysctl.c

@@ -21,7 +21,7 @@
 
 #define list_for_each_table_entry(entry, header)	\
 	entry = header->ctl_table;			\
-	for (size_t i = 0 ; i < header->ctl_table_size && entry->procname; ++i, entry++)
+	for (size_t i = 0 ; i < header->ctl_table_size; ++i, entry++)
 
 static const struct dentry_operations proc_sys_dentry_operations;
 static const struct file_operations proc_sys_file_operations;

net/sysctl_net.c

@@ -127,7 +127,7 @@ static void ensure_safe_net_sysctl(struct net *net, const char *path,
 
 	pr_debug("Registering net sysctl (net %p): %s\n", net, path);
 	ent = table;
-	for (size_t i = 0; i < table_size && ent->procname; ent++, i++) {
+	for (size_t i = 0; i < table_size; ent++, i++) {
 		unsigned long addr;
 		const char *where;
 
@@ -165,17 +165,10 @@ struct ctl_table_header *register_net_sysctl_sz(struct net *net,
 						struct ctl_table *table,
 						size_t table_size)
 {
-	int count;
-	struct ctl_table *entry;
-
 	if (!net_eq(net, &init_net))
 		ensure_safe_net_sysctl(net, path, table, table_size);
 
-	entry = table;
-	for (count = 0 ; count < table_size && entry->procname; entry++, count++)
-		;
-
-	return __register_sysctl_table(&net->sysctls, path, table, count);
+	return __register_sysctl_table(&net->sysctls, path, table, table_size);
 }
 EXPORT_SYMBOL_GPL(register_net_sysctl_sz);