On 18/06/21 09:00, Greg KH wrote:
+struct kvm_stats_header { + __u32 name_size; + __u32 count; + __u32 desc_offset; + __u32 data_offset; + char id[]; +};You mentioned before that the size of this really is the size of the structure + KVM_STATS_ID_MAXLEN, right? Or is it - KVM_STATS_ID_MAXLEN? If so, why not put that value explicitly in: char id[THE_REST_OF_THE_HEADER_SPACE]; As this is not a variable header size at all, and you can not change it going forward, so the variable length array here feels disingenuous.
It can change; the header goes up to desc_offset. Let's rename desc_offset to header_size.
+struct kvm_stats_desc { + __u32 flags; + __s16 exponent; + __u16 size; + __u32 offset; + __u32 unused; + char name[]; +};What is the max length of name?
It's name_size in the header.
Why aren't these structures defined here in kerneldoc so that we can understand them better? Putting them in a .rst file guarantees they will get out of sync, and you can always directly import the kerneldoc into the .rst file.
This is a problem in general with Documentation/virt/kvm/api.rst. The file is organized to match the kerneldoc structs to the ioctl that they are used for, and sometimes a ioctl includes different structs for each architecture.
It is probably possible to do it using :identifiers: and/or :doc:, but it would require running scripts/kernel-doc on the uAPI headers dozens of times. That is quite expensive at 0.3s each run, but that's what you get with Perl (gcc -fsyntax-only is 20 times faster).
Paolo
