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I'm fine if there is a >> benefit to doing so, but would like to understand what we gain. > > Well, maybe not "a lot" of code, but in general, it eliminates the need t= o test for empty slices > every time. =C2=A0If get_bytes() returns success, you know that you actua= lly do have some bytes. > > For example: > > let sig_bytes =3D self.get_bytes(b"SIGN")?; > > // Ensure that sig_bytes can be divided evenly into chunks. > if sig_bytes.len() % num_sigs !=3D 0 { > return Err(EINVAL); > } > > // num_sigs cannot be 0, and sig_bytes cannot be empty, so this c= annot panic. > let sig_size =3D sig_bytes.len() / num_sigs; > > sig_bytes.len() cannot be 0, so we know that sig_size cannot be 0, and th= erefore > > sig_bytes.chunks_exact(sig_size).nth(index).ok_or(EINVAL) > > chunks_exact() cannot fail. Basically we want a guarantee that `sig_size` is not zero. I'd prefer if we could enforce that using the type system rather than relying on a guarantee that `get_bytes` doesn't return an empty slice, because even that guarantee alone is not enough - we also need `num_sigs > 0` and `sig_bytes.len() % num_sigs =3D=3D 0` for that. All these conditions are spread around in the code, so I think it is a good opportunity to gather them together, and use `NonZero` to hold the guarantee we want. Something like this: let num_sigs =3D usize::from_safe_cast(tlv.get_u32(b"NSIG")?); // Size of one signature - Booter is always signed let sig_size =3D if (1..=3D15).contains(&num_sigs) && sig_bytes.len() %= num_sigs =3D=3D 0 { NonZero::new(sig_bytes.len() / num_sigs) } else { None } .ok_or_else(|| { dev_err!(dev, "invalid signature count {}\n", num_sigs); EINVAL })?; ... // PANIC: `sig_size` is `NonZero`, so `chunks_exact` cannot panic. let sig_chunk =3D sig_bytes.chunks_exact(sig_size.get()).nth(index).ok_= or(EINVAL)?; This is more sound as the guarantee we need is carried by the type of `sig_size`, and with that there is no need to make `get_bytes` return an error on empty slices.