[PATCH net-next] ipv4: delete sysctls about routing cache

[PATCH net-next] ipv4: delete sysctls about routing cache

[cgel.zte]

From: xu xin <xu.xin16@zte.com.cn>

Since routing cache in ipv4 has been deleted in 2012, the sysctls about
it are useless.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
 include/uapi/linux/sysctl.h | 10 ++++----
 net/ipv4/route.c            | 48 -------------------------------------
 2 files changed, 5 insertions(+), 53 deletions(-)

diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
index 6a3b194c50fe..72ecdf38c4ed 100644
--- a/include/uapi/linux/sysctl.h
+++ b/include/uapi/linux/sysctl.h
@@ -432,9 +432,9 @@ enum {
 	NET_IPV4_ROUTE_FLUSH=1,
 	NET_IPV4_ROUTE_MIN_DELAY=2, /* obsolete since 2.6.25 */
 	NET_IPV4_ROUTE_MAX_DELAY=3, /* obsolete since 2.6.25 */
-	NET_IPV4_ROUTE_GC_THRESH=4,
-	NET_IPV4_ROUTE_MAX_SIZE=5,
-	NET_IPV4_ROUTE_GC_MIN_INTERVAL=6,
+	NET_IPV4_ROUTE_GC_THRESH=4, /* obsolete */
+	NET_IPV4_ROUTE_MAX_SIZE=5,  /* obsolete */
+	NET_IPV4_ROUTE_GC_MIN_INTERVAL=6, /* obsolete */
 	NET_IPV4_ROUTE_GC_TIMEOUT=7,
 	NET_IPV4_ROUTE_GC_INTERVAL=8, /* obsolete since 2.6.38 */
 	NET_IPV4_ROUTE_REDIRECT_LOAD=9,
@@ -442,12 +442,12 @@ enum {
 	NET_IPV4_ROUTE_REDIRECT_SILENCE=11,
 	NET_IPV4_ROUTE_ERROR_COST=12,
 	NET_IPV4_ROUTE_ERROR_BURST=13,
-	NET_IPV4_ROUTE_GC_ELASTICITY=14,
+	NET_IPV4_ROUTE_GC_ELASTICITY=14, /* obsolete */
 	NET_IPV4_ROUTE_MTU_EXPIRES=15,
 	NET_IPV4_ROUTE_MIN_PMTU=16,
 	NET_IPV4_ROUTE_MIN_ADVMSS=17,
 	NET_IPV4_ROUTE_SECRET_INTERVAL=18,
-	NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS=19,
+	NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS=19, /* obsolete */
 };
 
 enum
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 843a7a3699fe..4b0d7d654859 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -110,7 +110,6 @@
 
 #define RT_GC_TIMEOUT (300*HZ)
 
-static int ip_rt_max_size;
 static int ip_rt_redirect_number __read_mostly	= 9;
 static int ip_rt_redirect_load __read_mostly	= HZ / 50;
 static int ip_rt_redirect_silence __read_mostly	= ((HZ / 50) << (9 + 1));
@@ -3428,8 +3427,6 @@ void ip_rt_multicast_event(struct in_device *in_dev)
 }
 
 #ifdef CONFIG_SYSCTL
-static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
-static int ip_rt_gc_min_interval __read_mostly	= HZ / 2;
 static int ip_rt_gc_elasticity __read_mostly	= 8;
 static int ip_min_valid_pmtu __read_mostly	= IPV4_MIN_MTU;
 
@@ -3448,36 +3445,6 @@ static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
 }
 
 static struct ctl_table ipv4_route_table[] = {
-	{
-		.procname	= "gc_thresh",
-		.data		= &ipv4_dst_ops.gc_thresh,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-	{
-		.procname	= "max_size",
-		.data		= &ip_rt_max_size,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-	{
-		/*  Deprecated. Use gc_min_interval_ms */
-
-		.procname	= "gc_min_interval",
-		.data		= &ip_rt_gc_min_interval,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_jiffies,
-	},
-	{
-		.procname	= "gc_min_interval_ms",
-		.data		= &ip_rt_gc_min_interval,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_ms_jiffies,
-	},
 	{
 		.procname	= "gc_timeout",
 		.data		= &ip_rt_gc_timeout,
@@ -3485,13 +3452,6 @@ static struct ctl_table ipv4_route_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
-	{
-		.procname	= "gc_interval",
-		.data		= &ip_rt_gc_interval,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_jiffies,
-	},
 	{
 		.procname	= "redirect_load",
 		.data		= &ip_rt_redirect_load,
@@ -3527,13 +3487,6 @@ static struct ctl_table ipv4_route_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{
-		.procname	= "gc_elasticity",
-		.data		= &ip_rt_gc_elasticity,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 	{
 		.procname	= "mtu_expires",
 		.data		= &ip_rt_mtu_expires,
@@ -3705,7 +3658,6 @@ int __init ip_rt_init(void)
 		panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
 
 	ipv4_dst_ops.gc_thresh = ~0;
-	ip_rt_max_size = INT_MAX;
 
 	devinet_init();
 	ip_fib_init();
-- 
2.25.1

Re: [PATCH net-next] ipv4: delete sysctls about routing cache

[Jakub Kicinski]

On Thu, 23 Dec 2021 12:20:10 +0000 cgel.zte@gmail.com wrote:
> From: xu xin <xu.xin16@zte.com.cn>
> 
> Since routing cache in ipv4 has been deleted in 2012, the sysctls about
> it are useless.

Search for those on GitHub. Useless or not, there is software which
expects those files to exist and which may break if they disappear.
That's why they were left in place.

Re: [PATCH net-next] ipv4: delete sysctls about routing cache

[CGEL]

On Thu, Dec 23, 2021 at 08:47:02AM -0800, Jakub Kicinski wrote:
> On Thu, 23 Dec 2021 12:20:10 +0000 cgel.zte@gmail.com wrote:
> > From: xu xin <xu.xin16@zte.com.cn>
> > 
> > Since routing cache in ipv4 has been deleted in 2012, the sysctls about
> > it are useless.
> 
> Search for those on GitHub. Useless or not, there is software which
> expects those files to exist and which may break if they disappear.
> That's why they were left in place.
Maybe we can note these inoperative interfaces in ip-sysctl.rst or
somewhere else, suggesting users not to use them any longer.

Wish you merry christmas in advance.
Xu Xin