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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Stefan Hajnoczi , Shuah Khan , Bobby Eshleman , "Michael S. Tsirkin" , Jonathan Corbet , Shuah Khan , virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH net v2 3/3] vsock: document write-once behavior of the child_ns_mode sysctl Message-ID: References: <20260218-vsock-ns-write-once-v2-0-19e4c50d509a@meta.com> <20260218-vsock-ns-write-once-v2-3-19e4c50d509a@meta.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: > > From: Bobby Eshleman > > > > Update the vsock child_ns_mode documentation to include the new the > > nit: s/the new the/the new > > > 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. > > > > > Signed-off-by: Bobby Eshleman > > --- > > 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. > > > + > > 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 > > >