netdev - Re: [PATCH net-next v6 1/1] net sched actions: Add support for user cookies

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Date:   Mon, 23 Jan 2017 13:58:40 +0100
From:   Simon Horman <simon.horman@...ronome.com>
To:     Jamal Hadi Salim <jhs@...atatu.com>
Cc:     davem@...emloft.net, netdev@...r.kernel.org, jiri@...lanox.com,
        paulb@...lanox.com, john.fastabend@...il.com, mrv@...atatu.com,
        hadarh@...lanox.com, ogerlitz@...lanox.com, roid@...lanox.com,
        xiyou.wangcong@...il.com, daniel@...earbox.net
Subject: Re: [PATCH net-next v6 1/1] net sched actions: Add support for user
 cookies

Hi Jamal,

On Sun, Jan 22, 2017 at 03:25:50PM -0500, Jamal Hadi Salim wrote:

...

> diff --git a/net/sched/act_api.c b/net/sched/act_api.c
> index cd08df9..58cf1c5 100644
> --- a/net/sched/act_api.c
> +++ b/net/sched/act_api.c
> @@ -24,6 +24,7 @@
>  #include <net/net_namespace.h>
>  #include <net/sock.h>
>  #include <net/sch_generic.h>
> +#include <net/pkt_cls.h>
>  #include <net/act_api.h>
>  #include <net/netlink.h>
>  
> @@ -33,6 +34,8 @@ static void free_tcf(struct rcu_head *head)
>  
>  	free_percpu(p->cpu_bstats);
>  	free_percpu(p->cpu_qstats);
> +	kfree(p->act_cookie->data);

Does the above need to be protected by a check for p->act_cookie being non-NULL?

> +	kfree(p->act_cookie);
>  	kfree(p);
>  }
>  

...

> @@ -575,6 +584,33 @@ struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla,
>  	if (err < 0)
>  		goto err_mod;
>  
> +	if (tb[TCA_ACT_COOKIE]) {
> +		int cklen = nla_len(tb[TCA_ACT_COOKIE]);
> +
> +		if (cklen > TC_COOKIE_MAX_SIZE) {
> +			err = -EINVAL;
> +			tcf_hash_release(a, bind);
> +			goto err_mod;
> +		}
> +
> +		a->act_cookie = kzalloc(sizeof(*a->act_cookie), GFP_KERNEL);
> +		if (!a->act_cookie) {
> +			err = -ENOMEM;
> +			tcf_hash_release(a, bind);
> +			goto err_mod;
> +		}
> +
> +		a->act_cookie->data = nla_memdup(tb[TCA_ACT_COOKIE],
> +						 GFP_KERNEL);
> +		if (!a->act_cookie->data) {
> +			err = -ENOMEM;
> +			kfree(a->act_cookie);
> +			tcf_hash_release(a, bind);
> +			goto err_mod;
> +		}
> +		a->act_cookie->len = cklen;

FWIW, the above looks correct but it also looks like the error handling
could be done less verbosely if the logic was moved to a separate function.

> +	}
> +
>  	/* module count goes up only when brand new policy is created
>  	 * if it exists and is only bound to in a_o->init() then
>  	 * ACT_P_CREATED is not returned (a zero is).
> -- 
> 1.9.1
>