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AJvYcCVnRIy1CWUw+QcTPLNm7pShDE//tc8ugSZ3RTiY2FhuzsCceIdzKisYw83rMFNXqw2KxHt6MMvdiA==@vger.kernel.org X-Gm-Message-State: AOJu0YzRG3kwFWUg4vEdZScjTGFezGJimtKib92iuJW3KfYz2CSKfIdd dUjrds9oixthI1LU+8y2IOo1031m1rjp9hSxJuRfeIpfbkEB4uZCVi+yJy3j4SEN9hvhB75Lm9J O/E4qGE586wGwsL+7gdg08okOi9fQ0QPaVfIfaHJ+KQg9LDlGDyiJ4Mek8Co= X-Gm-Gg: ASbGncuzz7eSfyVS0YLc64G4mYtpbEBhGW0Yp58Up1p+YtsiqdASH0Nji0Nc88WA2Sx 5reboZL6YiY/hxsrxKnjUr2wUvxZGw+aJ6J+6bj8hOLVt4rjXl5+MgNoAxbn0mrQVof4zTI7OOp 3DzZIxAGYFYfU87f9hikPa+Eqpxcgkr4Xq7d5EzH1VusXK0OCMteaCYaOrmUxu3IZECoX5Fux91 VCQNkBzwmFy/m4= X-Google-Smtp-Source: AGHT+IHT/6vjJ3shGdDPb9Fd3Wy97s1NrKmmnjPVT/7BhrMd3DmV+U6ospo8fL4BuQOHHl7LwakWHhHJqlcVvP+21aw= X-Received: by 2002:a05:6512:288:b0:557:e3bc:4950 with SMTP id 2adb3069b0e04-55e0706cc54mr65685e87.7.1755653480027; Tue, 19 Aug 2025 18:31:20 -0700 (PDT) Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <819d46e1354b0c7cc97945c6c7bde09f12df1da6.1755499376.git.asml.silence@gmail.com> In-Reply-To: From: Mina Almasry Date: Tue, 19 Aug 2025 18:31:08 -0700 X-Gm-Features: Ac12FXxQQ5U6eRVSrC6zCcNwvwL1-NkxxJKMgfbxZblDH0DrKqPtvKdkhFJsl34 Message-ID: Subject: Re: [PATCH net-next v3 14/23] net: add queue config validation callback To: Pavel Begunkov Cc: Jakub Kicinski , netdev@vger.kernel.org, Eric Dumazet , Willem de Bruijn , Paolo Abeni , andrew+netdev@lunn.ch, horms@kernel.org, davem@davemloft.net, sdf@fomichev.me, dw@davidwei.uk, michael.chan@broadcom.com, dtatulea@nvidia.com, ap420073@gmail.com, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Aug 19, 2025 at 2:54=E2=80=AFPM Mina Almasry wrote: > > On Mon, Aug 18, 2025 at 6:56=E2=80=AFAM Pavel Begunkov wrote: > > > > From: Jakub Kicinski > > > > I imagine (tm) that as the number of per-queue configuration > > options grows some of them may conflict for certain drivers. > > While the drivers can obviously do all the validation locally > > doing so is fairly inconvenient as the config is fed to drivers > > piecemeal via different ops (for different params and NIC-wide > > vs per-queue). > > > > Add a centralized callback for validating the queue config > > in queue ops. The callback gets invoked before each queue restart > > and when ring params are modified. > > > > For NIC-wide changes the callback gets invoked for each active > > (or active to-be) queue, and additionally with a negative queue > > index for NIC-wide defaults. The NIC-wide check is needed in > > case all queues have an override active when NIC-wide setting > > is changed to an unsupported one. Alternatively we could check > > the settings when new queues are enabled (in the channel API), > > but accepting invalid config is a bad idea. Users may expect > > that resetting a queue override will always work. > > > > The "trick" of passing a negative index is a bit ugly, we may > > want to revisit if it causes confusion and bugs. Existing drivers > > don't care about the index so it "just works". > > > > Signed-off-by: Jakub Kicinski > > Signed-off-by: Pavel Begunkov > > --- > > include/net/netdev_queues.h | 12 ++++++++++++ > > net/core/dev.h | 2 ++ > > net/core/netdev_config.c | 20 ++++++++++++++++++++ > > net/core/netdev_rx_queue.c | 6 ++++++ > > net/ethtool/rings.c | 5 +++++ > > 5 files changed, 45 insertions(+) > > > > diff --git a/include/net/netdev_queues.h b/include/net/netdev_queues.h > > index b850cff71d12..d0cc475ec51e 100644 > > --- a/include/net/netdev_queues.h > > +++ b/include/net/netdev_queues.h > > @@ -147,6 +147,14 @@ void netdev_stat_queue_sum(struct net_device *netd= ev, > > * defaults. Queue config structs are passed to th= is > > * helper before the user-requested settings are a= pplied. > > * > > + * @ndo_queue_cfg_validate: (Optional) Check if queue config is suppor= ted. > > + * Called when configuration affecting a queue may= be > > + * changing, either due to NIC-wide config, or con= fig > > + * scoped to the queue at a specified index. > > + * When NIC-wide config is changed the callback wi= ll > > + * be invoked for all queues, and in addition to t= hat > > + * with a negative queue index for the base settin= gs. > > + * > > * @ndo_queue_mem_alloc: Allocate memory for an RX queue at the specif= ied index. > > * The new memory is written at the specified add= ress. > > * > > @@ -167,6 +175,10 @@ struct netdev_queue_mgmt_ops { > > void (*ndo_queue_cfg_defaults)(struct net_device *dev, > > int idx, > > struct netdev_queue_config *q= cfg); > > + int (*ndo_queue_cfg_validate)(struct net_device *dev, > > + int idx, > > + struct netdev_queue_config *q= cfg, > > + struct netlink_ext_ack *extac= k); > > int (*ndo_queue_mem_alloc)(struct net_device *dev, > > struct netdev_queue_config *qcfg= , > > void *per_queue_mem, > > diff --git a/net/core/dev.h b/net/core/dev.h > > index a553a0f1f846..523d50e6f88d 100644 > > --- a/net/core/dev.h > > +++ b/net/core/dev.h > > @@ -99,6 +99,8 @@ void netdev_free_config(struct net_device *dev); > > int netdev_reconfig_start(struct net_device *dev); > > void __netdev_queue_config(struct net_device *dev, int rxq, > > struct netdev_queue_config *qcfg, bool pendi= ng); > > +int netdev_queue_config_revalidate(struct net_device *dev, > > + struct netlink_ext_ack *extack); > > > > /* netdev management, shared between various uAPI entry points */ > > struct netdev_name_node { > > diff --git a/net/core/netdev_config.c b/net/core/netdev_config.c > > index bad2d53522f0..fc700b77e4eb 100644 > > --- a/net/core/netdev_config.c > > +++ b/net/core/netdev_config.c > > @@ -99,3 +99,23 @@ void netdev_queue_config(struct net_device *dev, int= rxq, > > __netdev_queue_config(dev, rxq, qcfg, true); > > } > > EXPORT_SYMBOL(netdev_queue_config); > > + > > +int netdev_queue_config_revalidate(struct net_device *dev, > > + struct netlink_ext_ack *extack) > > +{ > > + const struct netdev_queue_mgmt_ops *qops =3D dev->queue_mgmt_op= s; > > + struct netdev_queue_config qcfg; > > + int i, err; > > + > > + if (!qops || !qops->ndo_queue_cfg_validate) > > + return 0; > > + > > + for (i =3D -1; i < (int)dev->real_num_rx_queues; i++) { > > + netdev_queue_config(dev, i, &qcfg); > > This function as written feels very useless tbh. There is no config > passed in from the caller, so the function does a netdev_queue_config, > which grabs the current-or-default-config (I'm not sure which tbh), > and then validates that is applicable. But of course the current or > default configs can be applied, right? > > I thought there would be a refactor in a future patch that makes this > function useful, but I don't see one. > > The qcfg being applied needs to be passed in by the caller of this > function, no? That would make sense to me (the caller is wondering if > this new config is applicable). > OK, I misunderstood how this works on first read. netdev_queue_config returns the pending config, not the current one, and that is what's being validated. I'll give this a closer look. --=20 Thanks, Mina