On Thu, 2017-01-26 at 07:50 +0100, Steffen Klassert wrote:
> This patch adds a napi instance for IPsec GRO.
> With this, we handle IPsec GRO with no impact
> on the generic networking code.
>
> Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com>
> ---
> net/xfrm/xfrm_input.c | 87
> ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 86 insertions(+), 1 deletion(-)
>
> diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
> index 6e3f025..c5fc12d 100644
> --- a/net/xfrm/xfrm_input.c
> +++ b/net/xfrm/xfrm_input.c
> @@ -21,6 +21,90 @@
> static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
> static struct xfrm_input_afinfo __rcu *xfrm_input_afinfo[NPROTO];
>
> +struct xfrm_napi {
> + struct sk_buff_head napi_skbs;
> + struct napi_struct napi;
> +};
> +
> +static struct xfrm_napi __percpu *napis;
> +
> +static void xfrm_gro_receive(struct sk_buff *skb)
> +{
> + struct xfrm_napi *xnapi;
> + struct net_device *dev = skb->dev;
> +
> + if (!napis || skb_cloned(skb) || !(dev->features & NETIF_F_GRO)) {
> + netif_rx(skb);
> + return;
> + }
> +
> + xnapi = this_cpu_ptr(napis);
> +
> + if (skb_queue_len(&xnapi->napi_skbs) > netdev_max_backlog) {
> + atomic_long_inc(&dev->rx_dropped);
> + kfree_skb(skb);
> + return;
> + }
> +
> + __skb_queue_tail(&xnapi->napi_skbs, skb);
> + if (skb_queue_len(&xnapi->napi_skbs) == 1)
> + napi_schedule(&xnapi->napi);
> +}
> +
> +static int xfrm_gro_poll(struct napi_struct *napi, int budget)
> +{
> + unsigned long flags;
> + struct sk_buff *skb;
> + int work_done = 0;
> + struct xfrm_napi *xnapi = container_of(napi, struct xfrm_napi, napi);
> +
> + while (work_done < budget) {
> + skb = __skb_dequeue(&xnapi->napi_skbs);
> + if (!skb)
> + break;
> + napi_gro_receive(napi, skb);
> + work_done++;
> + }
> +
> + if (work_done < budget) {
> + napi_gro_flush(napi, false);
> +
> + if (likely(list_empty(&napi->poll_list))) {
> + WARN_ON_ONCE(!test_and_clear_bit(NAPI_STATE_SCHED,
> &napi->state));
> + } else {
> + /* If n->poll_list is not empty, we need to mask irqs */
> + local_irq_save(flags);
> + __napi_complete(napi);
> + local_irq_restore(flags);
> + }
> + }
The following should work and contain less copy/pasted code.
if (work_done < budget)
napi_complete(napi);
> +
> + return work_done;
> +}
> +
> +static void xfrm_gro_init(void)
> +{
> + int i;
> +
> + /* Napi remains disabled if we can't alloc memory. */
> + napis = alloc_percpu(struct xfrm_napi);
napis can be NULL here.
> +
> + for_each_possible_cpu(i) {
> + struct xfrm_napi *xnapi = per_cpu_ptr(napis, i);
> +
> + __skb_queue_head_init(&xnapi->napi_skbs);
> +
> + set_bit(NAPI_STATE_NO_BUSY_POLL, &xnapi->napi.state);
> +
> + INIT_LIST_HEAD(&xnapi->napi.poll_list);
> + xnapi->napi.poll = xfrm_gro_poll;
> + xnapi->napi.weight = 64;
> + xnapi->napi.gro_list = NULL;
> + xnapi->napi.gro_count = 0;
> + xnapi->napi.skb = NULL;
> + }
> +}
Alternative would be to use a
static struct net_device xfrm_napi_anchor_device;
and use gro_cell
I will present in next netdev conference a work based on NAPI,
and having less hand coded napi logic will help a lot.
Thanks.
