Re: [PATCH] vfio: pci: use kzalloc_flex

[Gustavo A. R. Silva]

> > > > > Use __counted_by for extra runtime analysis. Move assignment to after
> > > > > allocation as required by __counted_by.
> > > >
> > > > I don't understand this statement, nr_ranges was previously set after
> > > > the allocation of phys_vec.  The only reordering was relative to
> > > > setting vdev, but that appears arbitrary.
> > > Yes that one. My understanding is __counted_by mandates immediate
> > > assignment after allocation. Otherwise UBSAN complains.
> >
> > Not true. However, it's best practice.
> >
> > The requirement is that the _counter_ must be initialized before
> > the first reference to the flexible-array member.
> OTOH kzalloc_flex automatically sets it for GCC15 and above. Useful to

That's what the "it's best practice." comment above alludes to.

-Gustavo