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Mon, 24 Aug 2026 11:29:25 -0700 (PDT) Date: Mon, 24 Aug 2026 20:29:23 +0200 From: Michal =?utf-8?Q?Koutn=C3=BD?= To: Jiri Pirko Cc: linux-rdma@vger.kernel.org, cgroups@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org, jgg@ziepe.ca, leon@kernel.org, parav@nvidia.com, mbloch@nvidia.com, cmeiohas@nvidia.com, roman.gushchin@linux.dev, bvanassche@acm.org, zyjzyj2000@gmail.com, shuah@kernel.org, tj@kernel.org, hannes@cmpxchg.org, alibuda@linux.alibaba.com, dust.li@linux.alibaba.com, sidraya@linux.ibm.com, wenjia@linux.ibm.com, yanjun.zhu@linux.dev, cui.tao@linux.dev Subject: Re: [PATCH rdma-next v3 08/14] RDMA/cgroup: Disambiguate devices across net namespaces Message-ID: References: <20260716132316.1495242-1-jiri@resnulli.us> <20260716132316.1495242-9-jiri@resnulli.us> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="cxu7rzeeuvesxlev" Content-Disposition: inline In-Reply-To: <20260716132316.1495242-9-jiri@resnulli.us> --cxu7rzeeuvesxlev Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH rdma-next v3 08/14] RDMA/cgroup: Disambiguate devices across net namespaces MIME-Version: 1.0 Hello Jiri. On Thu, Jul 16, 2026 at 03:23:09PM +0200, Jiri Pirko wro= te: > From: Jiri Pirko >=20 > RDMA device names are unique only within a network namespace, but an > RDMA cgroup can account resources for devices from multiple namespaces. > Duplicate names therefore make cgroup output ambiguous and can cause > limit writes to select the wrong device. =46rom the cover letter: | A device in one network namespace therefore cannot use a name already | taken in another, even in exclusive netns mode (netns_mode=3D0) where | the two are otherwise isolated. Net devices have no such restriction - | their names only need to be unique within a network namespace. If this is modelled after net devices, why not make the visibility netns based? I.e. only list (write to) devices of the caller's netns. >=20 > Use the system-wide RDMA device index to distinguish duplicate names > while preserving the existing UAPI for unique names. Reject ambiguous > name-only writes with -ENOTUNIQ and expose a complete device view to > administrators. I admit, the administrators won't get the full view but that's no different from the netns devices situation. Regards, Michal --cxu7rzeeuvesxlev Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJEEABYKADkWIQRCE24Fn/AcRjnLivR+PQLnlNv4CAUCaoyNfxsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMiwyLDIACgkQfj0C55Tb+Ag9cgEAmqyg7SX/4xxY6jGBQ6Ho ldb//2ddSquKpPFaT3oiD/8BAOPzNVL2AFncp/3gajGpePR8JfvA8gWP67r2kNjr koMD =6AcV -----END PGP SIGNATURE----- --cxu7rzeeuvesxlev--