netdev - Re: [net-next PATCH v8 5/8] cn10k-ipsec: Add SA add/del support for outb ipsec crypto offload

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Message-ID: <ZtbY9AF1fjUCcBOH@hog>
Date: Tue, 3 Sep 2024 11:37:56 +0200
From: Sabrina Dubroca <sd@...asysnail.net>
To: Bharat Bhushan <bbhushan2@...vell.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	sgoutham@...vell.com, gakula@...vell.com, sbhatta@...vell.com,
	hkelam@...vell.com, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com, jerinj@...vell.com,
	lcherian@...vell.com, richardcochran@...il.com,
	bharatb.linux@...il.com
Subject: Re: [net-next PATCH v8 5/8] cn10k-ipsec: Add SA add/del support for
 outb ipsec crypto offload

2024-09-03, 10:29:34 +0530, Bharat Bhushan wrote:
> +static int cn10k_ipsec_validate_state(struct xfrm_state *x)
> +{
> +	struct net_device *netdev = x->xso.dev;
> +
> +	if (x->props.aalgo != SADB_AALG_NONE) {
> +		netdev_err(netdev, "Cannot offload authenticated xfrm states\n");

This should use extack, to return this information directly to the
application that's creating the invalid config. You can propagate it
from cn10k_ipsec_add_state down to this function, and then:

    NL_SET_ERR_MSG_MOD(extack, "Cannot offload authenticated xfrm states");


> +static int cn10k_ipsec_inb_add_state(struct xfrm_state *x)
> +{
> +	struct net_device *netdev = x->xso.dev;
> +
> +	netdev_err(netdev, "xfrm inbound offload not supported\n");

Here too, extack.

> +	return -EOPNOTSUPP;
> +}
> +
> +static int cn10k_ipsec_outb_add_state(struct xfrm_state *x)
> +{
> +	struct net_device *netdev = x->xso.dev;
> +	struct cn10k_tx_sa_s *sa_entry;
> +	struct cpt_ctx_info_s *sa_info;
> +	struct otx2_nic *pf;
> +	int err;
> +
> +	err = cn10k_ipsec_validate_state(x);
> +	if (err)
> +		return err;
> +
> +	pf = netdev_priv(netdev);
> +	if (!mutex_trylock(&pf->ipsec.lock)) {

Why not wait until we can take the lock? Failing to offload the state
because this lock is temporarily busy isn't nice to users.

> +		netdev_err(netdev, "IPSEC device is busy\n");
> +		return -EBUSY;
> +	}
> +
> +	if (!(pf->flags & OTX2_FLAG_IPSEC_OFFLOAD_ENABLED)) {
> +		netdev_err(netdev, "IPSEC not enabled/supported on device\n");

You should also use extack in this function.


[...]
> +static void cn10k_ipsec_del_state(struct xfrm_state *x)
> +{
> +	struct net_device *netdev = x->xso.dev;
> +	struct cn10k_tx_sa_s *sa_entry;
> +	struct cpt_ctx_info_s *sa_info;
> +	struct otx2_nic *pf;
> +	int sa_index;
> +
> +	if (x->xso.dir == XFRM_DEV_OFFLOAD_IN)
> +		return;
> +
> +	pf = netdev_priv(netdev);
> +	if (!mutex_trylock(&pf->ipsec.lock)) {
> +		netdev_err(netdev, "IPSEC device is busy\n");
> +		return;

If we can't take the lock, we leave the state installed on the device
and leak some memory? That's not good. I assume we're going to reach
HW limits if this happens a bunch of times, and then we can't offload
ipsec at all anymore?

I think it would be better to wait until we can take the lock.

-- 
Sabrina