[PATCH] doc: networking: ip-sysctl: Document conf/all/disable_ipv6 and conf/default/disable_ipv6

[Pali Rohár]

This patch adds documentation for sysctl conf/all/disable_ipv6 and
conf/default/disable_ipv6 settings which is currently missing.

Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
---
 Documentation/networking/ip-sysctl.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index dd2b12a32b73..c7b775da9554 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1807,12 +1807,24 @@ seg6_flowlabel - INTEGER
 ``conf/default/*``:
 	Change the interface-specific default settings.
 
+	These settings would be used during creating new interfaces.
+
 
 ``conf/all/*``:
 	Change all the interface-specific settings.
 
 	[XXX:  Other special features than forwarding?]
 
+conf/all/disable_ipv6 - BOOLEAN
+	Changing this value is same as changing ``conf/default/disable_ipv6``
+	setting and also all per-interface ``disable_ipv6`` settings to the same
+	value.
+
+	Reading this value does not have any particular meaning. It does not say
+	whether IPv6 support is enabled or disabled. Returned value can be 1
+	also in the case when some interface has ``disable_ipv6`` set to 0 and
+	has configured IPv6 addresses.
+
 conf/all/forwarding - BOOLEAN
 	Enable global IPv6 forwarding between all interfaces.
 
-- 
2.20.1