On 11/19/25 1:23 AM, Michael S. Tsirkin wrote:
> On Wed, Nov 19, 2025 at 01:18:56AM -0600, Dan Jurgens wrote:
>> On 11/19/25 12:35 AM, Michael S. Tsirkin wrote:
>>> On Wed, Nov 19, 2025 at 12:26:23AM -0600, Dan Jurgens wrote:
>>>> On 11/18/25 3:55 PM, Michael S. Tsirkin wrote:
>>>>> On Tue, Nov 18, 2025 at 08:38:58AM -0600, Daniel Jurgens wrote:
>>>>>> Classifiers can be used by more than one rule. If there is an existing
>>>>>> classifier, use it instead of creating a new one.
>>>>
>>>>>> + struct virtnet_classifier *tmp;
>>>>>> + unsigned long i;
>>>>>> int err;
>>>>>>
>>>>>> - err = xa_alloc(&ff->classifiers, &c->id, c,
>>>>>> + xa_for_each(&ff->classifiers, i, tmp) {
>>>>>> + if ((*c)->size == tmp->size &&
>>>>>> + !memcmp(&tmp->classifier, &(*c)->classifier,
>>>>>> tmp->size)) {
>>>>>
>>>>> note that classifier has padding bytes.
>>>>> comparing these with memcmp is not safe, is it?
>>>>
>>>> The reserved bytes are set to 0, this is fine.
>>>
>>> I mean the compiler padding. set to 0 where?
>>
>> There's no compiler padding in virtio_net_ff_selector. There are
>> reserved fields between the count and selector array.
>
> I might be missing something here, but are not the
> structures this code compares of the type struct virtnet_classifier
> not virtio_net_ff_selector ?
>
> and that one is:
>
> struct virtnet_classifier {
> size_t size;
> + refcount_t refcount;
> u32 id;
> struct virtio_net_resource_obj_ff_classifier classifier;
> };
>
>
> which seems to have some padding depending on the architecture.
We're only comparing the ->classifier part of that, which is pad free.
>
>
>
