RE: [PATCH bpf-next 1/6] net: sk_msg: simplify sk_psock initialization

[John Fastabend]

Lorenz Bauer wrote:
> Initializing psock->sk_proto and other saved callbacks is only
> done in sk_psock_update_proto, after sk_psock_init has returned.
> The logic for this is difficult to follow, and needlessly complex.
> 
> Instead, initialize psock->sk_proto whenever we allocate a new
> psock. Additionally, assert the following invariants:
> 
> * The SK has no ULP: ULP does it's own finagling of sk->sk_prot
> * sk_user_data is unused: we need it to store sk_psock
> 
> Protect our access to sk_user_data with sk_callback_lock, which
> is what other users like reuseport arrays, etc. do.
> 
> The result is that an sk_psock is always fully initialized, and
> that psock->sk_proto is always the "original" struct proto.
> The latter allows us to use psock->sk_proto when initializing
> IPv6 TCP / UDP callbacks for sockmap.
> 
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> ---

Looks like a nice bit of cleanup thanks. I think we might be able to fold
up more of this code as well, but I'll take a look in a bit.

Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>