Re: [PATCH] netlink: use 48 byte ctx instead of 6 signed longs for callback

From: David Miller
Date: Mon Jul 01 2019 - 22:12:30 EST


From: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Date: Fri, 28 Jun 2019 16:42:26 +0200

> On Fri, 2019-06-28 at 16:40 +0200, Jason A. Donenfeld wrote:
>> People are inclined to stuff random things into cb->args[n] because it
>> looks like an array of integers. Sometimes people even put u64s in there
>> with comments noting that a certain member takes up two slots. The
>> horror! Really this should mirror the usage of skb->cb, which are just
>> 48 opaque bytes suitable for casting a struct. Then people can create
>> their usual casting macros for accessing strongly typed members of a
>> struct.
>>
>> As a plus, this also gives us the same amount of space on 32bit and 64bit.
>>
>> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
>> Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
>
> Reviewed-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>

Applied to net-next.