Re: [PATCH bpf-next v2 10/11] bpf: hoist type checking for nullable arg types

[Martin KaFai Lau <kafai@xxxxxx>]

On Wed, Sep 09, 2020 at 06:11:54PM +0100, Lorenz Bauer wrote:
> check_func_arg has a plethora of weird if statements with empty branches.
> They work around the fact that *_OR_NULL argument types should accept a
> SCALAR_VALUE register, as long as it's value is 0. These statements make
> it difficult to reason about the type checking logic.
> 
> Instead, skip more detailed type checking logic iff the register is 0,
> and the function expects a nullable type. This allows simplifying the type
> checking itself.
Acked-by: Martin KaFai Lau <kafai@xxxxxx>