Re: [PATCH bpf-next 1/5] bpf: add support for forced LINK_DETACH command

On Jul 29, 2020, at 4:05 PM, Andrii Nakryiko [off-list ref] 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.

Signed-off-by: Andrii Nakryiko <redacted>

The code looks good to me. My only question is, do we need both 
bpf_link_ops->detach and bpf_link_ops->release? 

Thanks,
Song

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