bpf: Fix and simplifications on inline map lookup
Fix in verifier:
For the same bpf_map_lookup_elem() instruction (i.e. "call 1"),
a broken case is "a different type of map could be used for the
same lookup instruction". For example, an array in one case and a
hashmap in another. We have to resort to the old dynamic call behavior
in this case. The fix is to check for collision on insn_aux->map_ptr.
If there is collision, don't inline the map lookup.
Please see the "do_reg_lookup()" in test_map_in_map_kern.c in the later
patch for how-to trigger the above case.
Simplifications on array_map_gen_lookup():
1. Calculate elem_size from map->value_size. It removes the
need for 'struct bpf_array' which makes the later map-in-map
implementation easier.
2. Remove the 'elem_size == 1' test
Fixes: 81ed18ab3098 ("bpf: add helper inlining infra and optimize map_array lookup")
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>
2 files changed
