diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index b8b67041f955..ba0e8e6337c0 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2808,7 +2808,14 @@ sctp_rmem - vector of 3 INTEGERs: min, default, max
 	Default: 4K
 
 sctp_wmem  - vector of 3 INTEGERs: min, default, max
-	Currently this tunable has no effect.
+	Only the first value ("min") is used, "default" and "max" are
+	ignored.
+
+	min: Minimum size of send buffer that can be used by SCTP sockets.
+	It is guaranteed to each SCTP socket (but not association) even
+	under moderate memory pressure.
+
+	Default: 4K
 
 addr_scope_policy - INTEGER
 	Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00