diff options
| -rw-r--r-- | kernel/bpf/hashtab.c | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index afe5bab376c9..000153acb6d5 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -419,7 +419,11 @@ again: return NULL; } -/* Called from syscall or from eBPF program */ +/* Called from syscall or from eBPF program directly, so + * arguments have to match bpf_map_lookup_elem() exactly. + * The return value is adjusted by BPF instructions + * in htab_map_gen_lookup(). + */ static void *__htab_map_lookup_elem(struct bpf_map *map, void *key) { struct bpf_htab *htab = container_of(map, struct bpf_htab, map); @@ -451,6 +455,30 @@ static void *htab_map_lookup_elem(struct bpf_map *map, void *key) return NULL; } +/* inline bpf_map_lookup_elem() call. + * Instead of: + * bpf_prog + * bpf_map_lookup_elem + * map->ops->map_lookup_elem + * htab_map_lookup_elem + * __htab_map_lookup_elem + * do: + * bpf_prog + * __htab_map_lookup_elem + */ +static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + + *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + return insn - insn_buf; +} + static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key) { struct htab_elem *l = __htab_map_lookup_elem(map, key); @@ -1062,6 +1090,7 @@ static const struct bpf_map_ops htab_ops = { .map_lookup_elem = htab_map_lookup_elem, .map_update_elem = htab_map_update_elem, .map_delete_elem = htab_map_delete_elem, + .map_gen_lookup = htab_map_gen_lookup, }; static struct bpf_map_type_list htab_type __ro_after_init = { |