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From: Petr Machata <petrm@nvidia.com>
To: David Ahern <dsahern@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>, Petr Machata <petrm@nvidia.com>,
	<netdev@vger.kernel.org>, David Ahern <dsahern@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Ido Schimmel <idosch@nvidia.com>
Subject: Re: [PATCH net-next 1/3] nexthop: Use a dedicated policy for nh_valid_get_del_req()
Date: Wed, 20 Jan 2021 11:45:37 +0100	[thread overview]
Message-ID: <87mtx36g4u.fsf@nvidia.com> (raw)
In-Reply-To: <74bb53b9-1bda-ba42-ceeb-9e85c8c2ea27@gmail.com>


David Ahern <dsahern@gmail.com> writes:

> On 1/19/21 1:55 PM, Jakub Kicinski wrote:
>>> diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
>>> index e53e43aef785..d5d88f7c5c11 100644
>>> --- a/net/ipv4/nexthop.c
>>> +++ b/net/ipv4/nexthop.c
>>> @@ -36,6 +36,10 @@ static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = {
>>>  	[NHA_FDB]		= { .type = NLA_FLAG },
>>>  };
>>>  
>>> +static const struct nla_policy rtm_nh_policy_get[NHA_MAX + 1] = {
>> 
>> This is an unnecessary waste of memory if you ask me.
>> 
>> NHA_ID is 1, so we're creating an array of 10 extra NULL elements.
>> 
>> Can you leave the size to the compiler and use ARRAY_SIZE() below?
>
> interesting suggestion in general for netlink attributes.
>
>> 
>>> +	[NHA_ID]		= { .type = NLA_U32 },
>>> +};
>>> +
>>>  static bool nexthop_notifiers_is_empty(struct net *net)
>>>  {
>>>  	return !net->nexthop.notifier_chain.head;
>>> @@ -1843,27 +1847,14 @@ static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id,
>>>  {
>>>  	struct nhmsg *nhm = nlmsg_data(nlh);
>>>  	struct nlattr *tb[NHA_MAX + 1];
>
> This tb array too could be sized to just the highest indexed expected -
> NHA_ID in this case.
>
>>> -	int err, i;
>>> +	int err;
>>>  
>>> -	err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
>>> +	err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy_get,
>>>  			  extack);

OK, I'll send a v2 that uses ARRAY_SIZE instead of hard-coding the max
and size.

  parent reply	other threads:[~2021-01-20 11:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-18 14:05 [PATCH net-next 0/3] nexthop: More fine-grained policies for netlink message validation Petr Machata
2021-01-18 14:05 ` [PATCH net-next 1/3] nexthop: Use a dedicated policy for nh_valid_get_del_req() Petr Machata
2021-01-18 17:41   ` David Ahern
2021-01-19 20:55   ` Jakub Kicinski
2021-01-20  2:28     ` David Ahern
2021-01-20  2:35       ` Jakub Kicinski
2021-01-20 10:45       ` Petr Machata [this message]
2021-01-18 14:05 ` [PATCH net-next 2/3] nexthop: Use a dedicated policy for nh_valid_dump_req() Petr Machata
2021-01-18 17:41   ` David Ahern
2021-01-19 20:55   ` Jakub Kicinski
2021-01-20 10:46     ` Petr Machata
2021-01-18 14:05 ` [PATCH net-next 3/3] nexthop: Specialize rtm_nh_policy Petr Machata
2021-01-18 17:42   ` David Ahern
2021-01-18 17:43 ` [PATCH net-next 0/3] nexthop: More fine-grained policies for netlink message validation David Ahern
2021-01-18 18:29   ` Ido Schimmel

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