On Thu, Feb 19, 2026 at 11:36:40AM +0100, Stefano Garzarella wrote:

On Wed, Feb 18, 2026 at 10:10:38AM -0800, Bobby Eshleman wrote:

quoted

From: Bobby Eshleman <redacted>

Update the vsock child_ns_mode documentation to include the new the

nit: s/the new the/the new

quoted

write-once semantics of setting child_ns_mode. The semantics are
implemented in a different patch in this series.

s/different/preceding ?

IMO this can be squashed with the previous patch, but not sure netdev policy
about that. Not a strong opinion, it's fine also in this way.

quoted

Signed-off-by: Bobby Eshleman <redacted>
---
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``.

nit: instead of saying that it can only be written once, we could say that
the first write locks the value, to be closer to the actual behavior,
something like this:

  The first write to ``child_ns_mode`` locks its value. Subsequent
  writes of the same value succeed, but writing a different value
  returns ``-EBUSY``.


Thanks,
Stefano

Sounds good! I agree that is more clear. I'll also remove the change
above that adds "Write-once" at the beginning of the paragraph, since
this clause does a better job explaining how it actually works.

quoted

+
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