[PATCH net v2 3/3] vsock: document write-once behavior of the child_ns_mode sysctl

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Bobby Eshleman <bobbyeshleman@meta.com>

Update the vsock child_ns_mode documentation to include the new the
write-once semantics of setting child_ns_mode. The semantics are
implemented in a different patch in this series.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 Documentation/admin-guide/sysctl/net.rst | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
index c10530624f1e..976a176fb451 100644
--- a/Documentation/admin-guide/sysctl/net.rst
+++ b/Documentation/admin-guide/sysctl/net.rst
@@ -581,9 +581,9 @@ The init_net mode is always ``global``.
 child_ns_mode
 -------------
 
-Controls what mode newly created child namespaces will inherit. At namespace
-creation, ``ns_mode`` is inherited from the parent's ``child_ns_mode``. The
-initial value matches the namespace's own ``ns_mode``.
+Write-once. Controls what mode newly created child namespaces will inherit. At
+namespace creation, ``ns_mode`` is inherited from the parent's
+``child_ns_mode``. The initial value matches the namespace's own ``ns_mode``.
 
 Values:
 
@@ -594,6 +594,10 @@ Values:
 	  their sockets will only be able to connect within their own
 	  namespace.
 
+``child_ns_mode`` can only be written once per namespace. Writing the same
+value that is already set succeeds. Writing a different value after the first
+write returns ``-EBUSY``.
+
 Changing ``child_ns_mode`` only affects namespaces created after the change;
 it does not modify the current namespace or any existing children.
 

-- 
2.47.3