John Fastabend <john.fastabend@xxxxxxxxx> writes:
> Lorenzo Bianconi wrote:
>> From: Toke Hoiland-Jorgensen <toke@xxxxxxxxxx>
>>
>> The check for tail call map compatibility ensures that tail calls only
>> happen between maps of the same type. To ensure backwards compatibility for
>> XDP multi-buffer we need a similar type of check for cpumap and devmap
>> programs, so move the state from bpf_array_aux into bpf_map, add xdp_mb to
>> the check, and apply the same check to cpumap and devmap.
>>
>> Co-developed-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
>> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
>> Signed-off-by: Toke Hoiland-Jorgensen <toke@xxxxxxxxxx>
>> ---
>
> ...
>
>> -bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
>> +static inline bool map_type_contains_progs(struct bpf_map *map)
>
> Maybe map_type_check_needed()? Just noticing that devmap doesn't contain
> progs.
Ah, but it does :)
See: fbee97feed9b ("bpf: Add support to attach bpf program to a devmap entry")
Indeed this feature is why this check is needed, so I think the name is
accurate...
-Toke
