From: John Fastabend <john.r.fastabend@intel•com>
To: davem@davemloft•net, netdev@vger•kernel.org, eric.dumazet@gmail•com
Subject: Re: [RFC PATCH v2 2/3] netlink: implement nla_policy for HW QOS
Date: Thu, 02 Dec 2010 11:53:37 -0800 [thread overview]
Message-ID: <4CF7F941.6080701@intel.com> (raw)
In-Reply-To: <20101202102037.GB10221@canuck.infradead.org>
On 12/2/2010 2:20 AM, Thomas Graf wrote:
> On Wed, Dec 01, 2010 at 10:22:58AM -0800, John Fastabend wrote:
>> +
>> + NLA_PUT_U8(skb, IFLA_TC_TXMAX, dev->max_tcs);
>> + NLA_PUT_U8(skb, IFLA_TC_TXNUM, dev->num_tcs);
>> +
>> + tc_txq = nla_nest_start(skb, IFLA_TC_TXQS);
>
> You have to check the return value here.
>
>> + for (i = 0; i < dev->num_tcs; i++) {
>> + tcq = netdev_get_tc_queue(dev, i);
>> + ifla_tcq.tc = i;
>> + ifla_tcq.count = tcq->count;
>> + ifla_tcq.offset = tcq->offset;
>> +
>> + NLA_PUT(skb, IFLA_TC_TXQ, sizeof(ifla_tcq), &ifla_tcq);
>> + }
>> + nla_nest_end(skb, tc_txq);
>> +
>> + tc_map = nla_nest_start(skb, IFLA_TC_MAPS);
>
> Same here
>
>> + for (i = 0; i < 16; i++) {
>> + ifla_map.prio = i;
>> + ifla_map.tc = netdev_get_prio_tc_map(dev, i);
>> + NLA_PUT(skb, IFLA_TC_MAP, sizeof(ifla_map), &ifla_map);
>> + }
>>
>> +
>> +static const struct nla_policy ifla_tc_txq[IFLA_TC_TXQS_MAX+1] = {
>> + [IFLA_TC_TXQ] = { .type = NLA_BINARY,
>> + .len = sizeof(struct ifla_tc_txq)},
>
> This is probably not what you want. NLA_BINARY only enforces a maximum
> payload length but no minimum payload length.
>
> Omit the .type and let it fall back to NLA_UNSPEC and only specify a
> .len. This enforces that the attribute payload is at least .len in
> length. You should not worry about payload that exceeds your size
> expectations. This allows to extend ifla_tc_txq in the future.
>
>> +static const struct nla_policy ifla_tc_map[IFLA_TC_MAPS_MAX+1] = {
>> + [IFLA_TC_MAP] = { .type = NLA_BINARY,
>> + .len = sizeof(struct ifla_tc_map)},
>> +};
>
> Same here
errors noted. Thanks for the clarification I'll fix this up. Also I'll look into Jamal's comment regarding moving this to use 'tc'.
-- John
next prev parent reply other threads:[~2010-12-02 19:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-01 18:22 [RFC PATCH v2 1/3] net: implement mechanism for HW based QOS John Fastabend
2010-12-01 18:22 ` [RFC PATCH v2 2/3] netlink: implement nla_policy for HW QOS John Fastabend
2010-12-02 10:20 ` Thomas Graf
2010-12-02 19:53 ` John Fastabend [this message]
2010-12-01 18:23 ` [RFC PATCH v2 3/3] ixgbe: add multiple txqs per tc John Fastabend
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