linux_dsm_epyc7002/kernel/bpf
Martin KaFai Lau 56f668dfe0 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>
2017-03-22 15:45:45 -07:00
..
arraymap.c bpf: Add array of maps support 2017-03-22 15:45:45 -07:00
bpf_lru_list.c bpf: Make unnecessarily global functions static 2017-01-10 21:00:59 -05:00
bpf_lru_list.h bpf: Add percpu LRU list 2016-11-15 11:50:20 -05:00
cgroup.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
core.c bpf: make jited programs visible in traces 2017-02-17 13:40:05 -05:00
hashtab.c bpf: inline htab_map_lookup_elem() 2017-03-16 20:44:11 -07:00
helpers.c bpf: rename ARG_PTR_TO_STACK 2017-01-09 16:56:27 -05:00
inode.c bpf: add initial bpf tracepoints 2017-01-25 13:17:47 -05:00
lpm_trie.c bpf: add get_next_key callback to LPM map 2017-03-05 17:55:29 -08:00
Makefile bpf: Add array of maps support 2017-03-22 15:45:45 -07:00
map_in_map.c bpf: Add array of maps support 2017-03-22 15:45:45 -07:00
map_in_map.h bpf: Add array of maps support 2017-03-22 15:45:45 -07:00
percpu_freelist.c bpf: introduce percpu_freelist 2016-03-08 15:28:31 -05:00
percpu_freelist.h bpf: introduce percpu_freelist 2016-03-08 15:28:31 -05:00
stackmap.c bpf: mark all registered map/prog types as __ro_after_init 2017-02-17 13:40:04 -05:00
syscall.c bpf: Add array of maps support 2017-03-22 15:45:45 -07:00
verifier.c bpf: Add array of maps support 2017-03-22 15:45:45 -07:00