bpf, netns: Keep a list of attached bpf_link's

To support multi-prog link-based attachments for new netns attach types, we
need to keep track of more than one bpf_link per attach type. Hence,
convert net->bpf.links into a list, that currently can be either empty or
have just one item.

Instead of reusing bpf_prog_list from bpf-cgroup, we link together
bpf_netns_link's themselves. This makes list management simpler as we don't
have to allocate, initialize, and later release list elements. We can do
this because multi-prog attachment will be available only for bpf_link, and
we don't need to build a list of programs attached directly and indirectly
via links.

No functional changes intended.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-4-jakub@cloudflare.com
This commit is contained in:
Jakub Sitnicki 2020-06-25 16:13:56 +02:00 committed by Alexei Starovoitov
parent 695c12147a
commit ab53cad90e
2 changed files with 24 additions and 20 deletions

View file

@ -15,7 +15,7 @@ struct netns_bpf {
/* Array of programs to run compiled from progs or links */
struct bpf_prog_array __rcu *run_array[MAX_NETNS_BPF_ATTACH_TYPE];
struct bpf_prog *progs[MAX_NETNS_BPF_ATTACH_TYPE];
struct bpf_link *links[MAX_NETNS_BPF_ATTACH_TYPE];
struct list_head links[MAX_NETNS_BPF_ATTACH_TYPE];
};
#endif /* __NETNS_BPF_H__ */