On Mon, 26 Jan 2026 19:06:49 -0800 Bobby Eshleman wrote:

quoted

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Then, if the dmabuf count encoding space is exhausted, the socket would
have to wait until the user returns all of the tokens from one of the
dmabufs and frees the ID (or err out is another option).

This wouldn't change adding a field to the socket, we'd have to add one
or two more for allocating the dmabuf ID and fetching the dmabuf with
it. But it does fix the single binding thing.  

I think the bigger problem (than space exhaustion) is that we'd also
have some understanding of permissions. If an application guesses 
the binding ID of another app it can mess up its buffers. ENOBUENO..  

I was thinking it would be per-socket, effectively:

sk->sk_devmem_info.bindings[binding_id_from_token(token)]

So sockets could only access those that they have already recv'd on.

Ah, missed that the array would be per socket. I guess it'd have to be
reusing the token xarray otherwise we're taking up even more space in
the socket struct? Dunno.