[bpf-next,0/1] Refactor cgroup_bpf internals to use more specific attach_type

Message

Dave Marchevsky July 31, 2021, 11:30 p.m. UTC

The cgroup_bpf struct has a few arrays (effective, progs, and flags) of
size MAX_BPF_ATTACH_TYPE. These are meant to separate progs by their
attach type, currently represented by the bpf_attach_type enum.

There are some bpf_attach_type values which are not valid attach types
for cgroup bpf programs. Programs with these attach types will never be
handled by cgroup_bpf_{attach,detach} and thus will never be held in
cgroup_bpf structs. Even if such programs did make it into their
reserved slot in those arrays, they would never be executed.

Accordingly we can migrate to a new internal cgroup_bpf-specific enum
for these arrays, saving some bytes per cgroup and making it more
obvious which BPF programs belong there. netns_bpf_attach_type is an
existing example of this pattern, let's do similar for cgroup_bpf.

Dave Marchevsky (1):
  bpf: migrate cgroup_bpf to internal cgroup_bpf_attach_type enum

 include/linux/bpf-cgroup.h     | 200 +++++++++++++++++++++++----------
 include/uapi/linux/bpf.h       |   2 +-
 kernel/bpf/cgroup.c            | 154 +++++++++++++++----------
 net/ipv4/af_inet.c             |   6 +-
 net/ipv4/udp.c                 |   2 +-
 net/ipv6/af_inet6.c            |   6 +-
 net/ipv6/udp.c                 |   2 +-
 tools/include/uapi/linux/bpf.h |   2 +-
 8 files changed, 243 insertions(+), 131 deletions(-)