This patch set adds support to access bpf map fields from bpf programs using btf_struct_access(). That way a program can cast a pointer to map to either `struct bpf_map *` or map type specific struct pointer such as `struct bpf_array *` or `struct bpf_htab *`, and access necessary fields, e.g. map->max_entries. The fields, in turn, should be defined by a user provided struct with preserve_access_index attribute or included from vmlinux.h. Please see patch 4 for more details on the feature and use-cases. Other patches: Patch 1 is refactoring to simplify btf_parse_vmlinux(). Patch 2 introduces a new function to simplify iteration over btf. Patch 3 is a rename to avoid having two different `struct bpf_htab`. Patch 5 enables access to map fields for all map types. Patch 6 adds selftests. Andrey Ignatov (6): bpf: Switch btf_parse_vmlinux to btf_find_by_name_kind bpf: Introduce btf_find_by_name_kind_next() bpf: Rename bpf_htab to bpf_shtab in sock_map bpf: Support access to bpf map fields bpf: Set map_btf_name for all map types selftests/bpf: Test access to bpf map pointer include/linux/bpf.h | 8 + include/linux/bpf_verifier.h | 1 + include/linux/btf.h | 2 + kernel/bpf/arraymap.c | 6 + kernel/bpf/bpf_struct_ops.c | 1 + kernel/bpf/btf.c | 97 ++- kernel/bpf/cpumap.c | 1 + kernel/bpf/devmap.c | 2 + kernel/bpf/hashtab.c | 5 + kernel/bpf/local_storage.c | 1 + kernel/bpf/lpm_trie.c | 1 + kernel/bpf/queue_stack_maps.c | 2 + kernel/bpf/reuseport_array.c | 1 + kernel/bpf/ringbuf.c | 1 + kernel/bpf/stackmap.c | 1 + kernel/bpf/verifier.c | 77 +- net/core/bpf_sk_storage.c | 1 + net/core/sock_map.c | 84 +-- net/xdp/xskmap.c | 1 + .../selftests/bpf/prog_tests/map_ptr.c | 32 + .../selftests/bpf/progs/map_ptr_kern.c | 686 ++++++++++++++++++ .../testing/selftests/bpf/verifier/map_ptr.c | 62 ++ .../selftests/bpf/verifier/map_ptr_mixing.c | 2 +- 23 files changed, 1007 insertions(+), 68 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/map_ptr.c create mode 100644 tools/testing/selftests/bpf/progs/map_ptr_kern.c create mode 100644 tools/testing/selftests/bpf/verifier/map_ptr.c -- 2.24.1
