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authorMartin KaFai Lau <kafai@fb.com>2017-03-22 20:00:33 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-23 01:45:45 +0300
commit56f668dfe00dcf086734f1c42ea999398fad6572 (patch)
treed233ae9458347dccd529e8be12e24d73bcb13617 /include/linux/bpf.h
parentfad73a1a35ea61f13607a391aca669caad8c04ca (diff)
downloadlinux-56f668dfe00dcf086734f1c42ea999398fad6572.tar.xz
bpf: Add array of maps support
This patch adds a few helper funcs to enable map-in-map support (i.e. outer_map->inner_map). The first outer_map type BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch. The next patch will introduce a hash of maps type. Any bpf map type can be acted as an inner_map. The exception is BPF_MAP_TYPE_PROG_ARRAY because the extra level of indirection makes it harder to verify the owner_prog_type and owner_jited. Multi-level map-in-map is not supported (i.e. map->map is ok but not map->map->map). When adding an inner_map to an outer_map, it currently checks the map_type, key_size, value_size, map_flags, max_entries and ops. The verifier also uses those map's properties to do static analysis. map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT is using a preallocated hashtab for the inner_hash also. ops and max_entries are needed to generate inlined map-lookup instructions. For simplicity reason, a simple '==' test is used for both map_flags and max_entries. The equality of ops is implied by the equality of map_type. During outer_map creation time, an inner_map_fd is needed to create an outer_map. However, the inner_map_fd's life time does not depend on the outer_map. The inner_map_fd is merely used to initialize the inner_map_meta of the outer_map. Also, for the outer_map: * It allows element update and delete from syscall * It allows element lookup from bpf_prog The above is similar to the current fd_array pattern. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/bpf.h')
-rw-r--r--include/linux/bpf.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index da8c64ca8dc9..3f3cdf9b15e8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -50,6 +50,7 @@ struct bpf_map {
const struct bpf_map_ops *ops;
struct work_struct work;
atomic_t usercnt;
+ struct bpf_map *inner_map_meta;
};
struct bpf_map_type_list {