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author | Martin KaFai Lau <kafai@fb.com> | 2017-03-22 18:00:33 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2017-03-22 23:45:45 +0100 |
commit | 56f668dfe00dcf086734f1c42ea999398fad6572 (patch) | |
tree | d233ae9458347dccd529e8be12e24d73bcb13617 /kernel/bpf/map_in_map.h | |
parent | bpf: Fix and simplifications on inline map lookup (diff) | |
download | linux-56f668dfe00dcf086734f1c42ea999398fad6572.tar.xz linux-56f668dfe00dcf086734f1c42ea999398fad6572.zip |
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 'kernel/bpf/map_in_map.h')
-rw-r--r-- | kernel/bpf/map_in_map.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/bpf/map_in_map.h b/kernel/bpf/map_in_map.h new file mode 100644 index 000000000000..177fadb689dc --- /dev/null +++ b/kernel/bpf/map_in_map.h @@ -0,0 +1,23 @@ +/* Copyright (c) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#ifndef __MAP_IN_MAP_H__ +#define __MAP_IN_MAP_H__ + +#include <linux/types.h> + +struct file; +struct bpf_map; + +struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd); +void bpf_map_meta_free(struct bpf_map *map_meta); +bool bpf_map_meta_equal(const struct bpf_map *meta0, + const struct bpf_map *meta1); +void *bpf_map_fd_get_ptr(struct bpf_map *map, struct file *map_file, + int ufd); +void bpf_map_fd_put_ptr(void *ptr); + +#endif |