Re: [PATCH v2 08/19] PCI/TSM: Add "evidence" support

[Dan Williams <dan.j.williams@intel.com>]

Jakub Kicinski wrote:
[..] 
> > > The main strength of Netlink is "do" commands with multiple optional
> > > attrs.  
> > 
> > Yes, that is attractive and saves a pile of bug prone ioctl handling.
> > 
> > The gap I need to fill first though is a uAPI that allows for large
> > blobs to be fetched after being regenerated / reformatted besed on some
> > input attributes.
> > 
> > "Multi message netlink attributes" while inventive, feels less awkward
> > and more future proof than a sysfs binary attribute scheme to do the
> > same.
> 
> Alright, so to make this more Netlink-y you can either:
>  - delete the F_MULTI and replicate other attrs in each message and 
>    add an offset attr; this will make each message in the dump more
>    standalone. 
>  - keep the F_MULTI but object_val has to be a multi-attr, and then 
>    we have to teach YNL to correctly append the attrs.
> 
> Former is definitely less work. Latter could end up being cleaner
> but there are some unknowns so hard to tell for sure; more plumbing.

Makes sense, and not yet sure which one is lower maintenance burden
long term. I will play with it a bit.

I am leaning to the first option more for the fact that it puts the
burden of being strange squarely on the implementation that wants it. If
this discussion attracts more large blob dumpers then the second option.

Thanks for spending some attention here.