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[82.53.134.58]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4839f99067dsm17354955e9.29.2026.02.19.02.36.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Feb 2026 02:36:42 -0800 (PST) Date: Thu, 19 Feb 2026 11:36:40 +0100 From: Stefano Garzarella To: Bobby Eshleman Cc: "David S. 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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20260218-vsock-ns-write-once-v2-3-19e4c50d509a@meta.com> 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 >+ > 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 >