Andrii Nakryiko wrote:
> Add LINK_DETACH command to force-detach bpf_link without destroying it. It has
> the same behavior as auto-detaching of bpf_link due to cgroup dying for
> bpf_cgroup_link or net_device being destroyed for bpf_xdp_link. In such case,
> bpf_link is still a valid kernel object, but is defuncts and doesn't hold BPF
> program attached to corresponding BPF hook. This functionality allows users
> with enough access rights to manually force-detach attached bpf_link without
> killing respective owner process.
>
> This patch implements LINK_DETACH for cgroup, xdp, and netns links, mostly
> re-using existing link release handling code.
>
> Acked-by: Song Liu <songliubraving@xxxxxx>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
Looks necessary otherwise we have no way, as far as I read it, to delete
an XDP program and go back the no prog state after link_{create|update}.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
