Re: [RFC net-next v2 2/2] tg3: Link queues to NAPIs

Joe Damato
2024-09-26T23:17:08Z

On Wed, Sep 25, 2024 at 04:20:48PM +0000, Joe Damato wrote:
> Link queues to NAPIs using the netdev-genl API so this information is
> queryable.
>
> $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
> --dump queue-get --json='{"ifindex": 2}'
>
> [{'id': 0, 'ifindex': 2, 'type': 'rx'},
> {'id': 1, 'ifindex': 2, 'napi-id': 146, 'type': 'rx'},
> {'id': 2, 'ifindex': 2, 'napi-id': 147, 'type': 'rx'},
> {'id': 3, 'ifindex': 2, 'napi-id': 148, 'type': 'rx'},
> {'id': 0, 'ifindex': 2, 'napi-id': 145, 'type': 'tx'}]
>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> ---
> drivers/net/ethernet/broadcom/tg3.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
> index ddf0bb65c929..f78d7e8c40b2 100644
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -7395,18 +7395,34 @@ static int tg3_poll(struct napi_struct *napi, int budget)
>
> static void tg3_napi_disable(struct tg3 *tp)
> {
> + struct tg3_napi *tnapi;
> int i;
>
> - for (i = tp->irq_cnt - 1; i >= 0; i--)
> - napi_disable(&tp->napi[i].napi);
> + ASSERT_RTNL();
> + for (i = tp->irq_cnt - 1; i >= 0; i--) {
> + tnapi = &tp->napi[i];
> + if (tnapi->tx_buffers)
> + netif_queue_set_napi(tp->dev, i, NETDEV_QUEUE_TYPE_TX, NULL);

It looks like the ASSERT_RTNL is unnecessary; netif_queue_set_napi
will call it internally, so I'll remove it before sending this to
the list (barring any other feedback).

> static void tg3_napi_enable(struct tg3 *tp)
> {
> + struct tg3_napi *tnapi;
> int i;
>
> - for (i = 0; i < tp->irq_cnt; i++)
> - napi_enable(&tp->napi[i].napi);
> + ASSERT_RTNL();
> + for (i = 0; i < tp->irq_cnt; i++) {
> + tnapi = &tp->napi[i];
> + napi_enable(&tnapi->napi);
> + if (tnapi->tx_buffers)
> + netif_queue_set_napi(tp->dev, i, NETDEV_QUEUE_TYPE_TX, &tnapi->napi);

Same as above.