Add an enum (cgroup_bpf_attach_type) containing only valid cgroup_bpf attach types and a function to map bpf_attach_type values to the new enum. Inspired by netns_bpf_attach_type. Then, migrate cgroup_bpf to use cgroup_bpf_attach_type wherever possible. Functionality is unchanged as attach_type_to_prog_type switches in bpf/syscall.c were preventing non-cgroup programs from making use of the invalid cgroup_bpf array slots. As a result struct cgroup_bpf uses 504 fewer bytes relative to when its arrays were sized using MAX_BPF_ATTACH_TYPE. bpf_cgroup_storage is notably not migrated as struct bpf_cgroup_storage_key is part of uapi and contains a bpf_attach_type member which is not meant to be opaque. Similarly, bpf_cgroup_link continues to report its bpf_attach_type member to userspace via fdinfo and bpf_link_info. To ease disambiguation, bpf_attach_type variables are renamed from 'type' to 'atype' when changed to cgroup_bpf_attach_type.
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| @@ -84,7 +84,7 @@ struct bpf_lpm_trie_key { · 83 unmodified lines | ||
| 84 | 84 | |
| 85 | 85 | struct bpf_cgroup_storage_key { |
| 86 | 86 | __u64 cgroup_inode_id; /* cgroup inode id */ |
| 87 | − __u32 attach_type; /* program attach type */ | |
| 87 | + __u32 attach_type; /* program attach type (enum bpf_attach_type) */ | |
| 88 | 88 | }; |
| 89 | 89 | |
| 90 | 90 | union bpf_iter_link_info { |