AX.25: Fix sysctl registration if !CONFIG_AX25_DAMA_SLAVE

[ Upstream commit ffb20847 ]

Since 49ffcf8f ("sysctl: update
sysctl_check_table") setting struct ctl_table.procname = NULL does no
longer work as it used to the way the AX.25 code is expecting it to
resulting in the AX.25 sysctl registration code to break if
CONFIG_AX25_DAMA_SLAVE was not set as in some distribution kernels.
Kernel releases from 2.6.24 are affected.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/ax25/sysctl_net_ax25.c

@@ -36,6 +36,7 @@ static struct ctl_path ax25_path[] = {
 	{ .procname = "ax25", .ctl_name = NET_AX25, },
 	{ }
 };
+
 static const ctl_table ax25_param_table[] = {
 	{
 		.ctl_name	= NET_AX25_IP_DEFAULT_MODE,
@@ -167,6 +168,7 @@ static const ctl_table ax25_param_table[] = {
 		.extra1		= &min_proto,
 		.extra2		= &max_proto
 	},
+#ifdef CONFIG_AX25_DAMA_SLAVE
 	{
 		.ctl_name	= NET_AX25_DAMA_SLAVE_TIMEOUT,
 		.procname	= "dama_slave_timeout",
@@ -177,6 +179,8 @@ static const ctl_table ax25_param_table[] = {
 		.extra1		= &min_ds_timeout,
 		.extra2		= &max_ds_timeout
 	},
+#endif
+
 	{ .ctl_name = 0 }	/* that's all, folks! */
 };
 
@@ -210,16 +214,6 @@ void ax25_register_sysctl(void)
 		ax25_table[n].procname     = ax25_dev->dev->name;
 		ax25_table[n].mode         = 0555;
 
-#ifndef CONFIG_AX25_DAMA_SLAVE
-		/*
-		 * We do not wish to have a representation of this parameter
-		 * in /proc/sys/ when configured *not* to include the
-		 * AX.25 DAMA slave code, do we?
-		 */
-
-		child[AX25_VALUES_DS_TIMEOUT].procname = NULL;
-#endif
-
 		child[AX25_MAX_VALUES].ctl_name = 0;	/* just in case... */
 
 		for (k = 0; k < AX25_MAX_VALUES; k++)