On Tue, Oct 3, 2017 at 10:39 AM, Daniel Borkmann <dan...@iogearbox.net> wrote:
> On 10/03/2017 01:07 AM, Alexei Starovoitov wrote:
>>
>> On 10/2/17 9:41 AM, Craig Gallek wrote:
>>>
>>> + /* Assume equally sized map definitions */
>>> + map_def_sz = data->d_size / nr_maps;
>>> + if (!data->d_size || (data->d_size % nr_maps) != 0) {
>>> + pr_warning("unable to determine map definition size "
>>> + "section %s, %d maps in %zd bytes\n",
>>> + obj->path, nr_maps, data->d_size);
>>> + return -EINVAL;
>>> + }
>>
>>
>> this approach is not as flexible as done by samples/bpf/bpf_load.c
>> where it looks at every map independently by walking symtab,
>> but I guess it's ok.
>
>
> Regarding different map spec structs in a single prog: unless
> we have a good use case why we would need it (and I'm not aware
> of anything in particular), I would just go with a fixed size.
> I did kind of similar sanity checks in bpf_fetch_maps_end() in
> iproute2 loader as well.
Split vote? I'm happy to try to make this work with varying sizes,
but I agree the usefulness seems low. It would imply building map
sections with different definition structures and we would then need a
way to differentiate them. If the goal is to allow for different map
definition structures, I don't think size alone is a sufficient
differentiator.
