From 57dc4fa63e53e55edfbc63c201726da185066d98 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 26 Feb 2021 12:49:27 -0800 Subject: [PATCH] bpf: Add hashtab support for bpf_for_each_map_elem() helper [upstream commit 314ee05e2fc601a7bece14376547d2b7a04bab67] This patch added support for hashmap, percpu hashmap, lru hashmap and percpu lru hashmap. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210226204927.3885020-1-yhs@fb.com --- include/linux/bpf.h | 4 +++ kernel/bpf/hashtab.c | 58 +++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 27 ++++++++++++++++++++ 3 files changed, 89 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 52ea23849..a6126da6f 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1190,6 +1190,10 @@ bool bpf_link_is_iter(struct bpf_link *link); struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop); int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx); +int map_set_for_each_callback_args(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee); + int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 592d68d70..63235a284 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1279,6 +1279,56 @@ static void htab_map_seq_show_elem(struct bpf_map *map, void *key, rcu_read_unlock(); } +static int bpf_for_each_hash_elem(struct bpf_map *map, void *callback_fn, + void *callback_ctx, u64 flags) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + struct htab_elem *elem; + u32 roundup_key_size; + int i, num_elems = 0; + void __percpu *pptr; + struct bucket *b; + void *key, *val; + bool is_percpu; + u64 ret = 0; + + if (flags != 0) + return -EINVAL; + + is_percpu = htab_is_percpu(htab); + + roundup_key_size = round_up(map->key_size, 8); + for (i = 0; i < htab->n_buckets; i++) { + b = &htab->buckets[i]; + rcu_read_lock(); + head = &b->head; + hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) { + key = elem->key; + if (is_percpu) { + /* current cpu value for percpu map */ + pptr = htab_elem_get_ptr(elem, map->key_size); + val = this_cpu_ptr(pptr); + } else { + val = elem->key + roundup_key_size; + } + num_elems++; + ret = BPF_CAST_CALL(callback_fn)((u64)(long)map, + (u64)(long)key, (u64)(long)val, + (u64)(long)callback_ctx, 0); + /* return value: 0 - continue, 1 - stop and return */ + if (ret) { + rcu_read_unlock(); + goto out; + } + } + rcu_read_unlock(); + } +out: + return num_elems; +} + static int htab_map_btf_id; struct bpf_iter_seq_hash_map_info { struct bpf_map *map; @@ -1480,6 +1530,8 @@ const struct bpf_map_ops htab_map_ops = { .map_delete_elem = htab_map_delete_elem, .map_gen_lookup = htab_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, + .map_set_for_each_callback_args = map_set_for_each_callback_args, + .map_for_each_callback = bpf_for_each_hash_elem, .map_btf_name = "bpf_htab", .map_btf_id = &htab_map_btf_id, .iter_seq_info = &iter_seq_info, @@ -1497,6 +1549,8 @@ const struct bpf_map_ops htab_lru_map_ops = { .map_delete_elem = htab_lru_map_delete_elem, .map_gen_lookup = htab_lru_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, + .map_set_for_each_callback_args = map_set_for_each_callback_args, + .map_for_each_callback = bpf_for_each_hash_elem, .map_btf_name = "bpf_htab", .map_btf_id = &htab_lru_map_btf_id, .iter_seq_info = &iter_seq_info, @@ -1614,6 +1668,8 @@ const struct bpf_map_ops htab_percpu_map_ops = { .map_update_elem = htab_percpu_map_update_elem, .map_delete_elem = htab_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, + .map_set_for_each_callback_args = map_set_for_each_callback_args, + .map_for_each_callback = bpf_for_each_hash_elem, .map_btf_name = "bpf_htab", .map_btf_id = &htab_percpu_map_btf_id, .iter_seq_info = &iter_seq_info, @@ -1629,6 +1685,8 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { .map_update_elem = htab_lru_percpu_map_update_elem, .map_delete_elem = htab_lru_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, + .map_set_for_each_callback_args = map_set_for_each_callback_args, + .map_for_each_callback = bpf_for_each_hash_elem, .map_btf_name = "bpf_htab", .map_btf_id = &htab_lru_percpu_map_btf_id, .iter_seq_info = &iter_seq_info, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5f5db7b83..3abe24b72 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4443,6 +4443,33 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn return 0; } +int map_set_for_each_callback_args(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee) +{ + /* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, + * void *callback_ctx, u64 flags); + * callback_fn(struct bpf_map *map, void *key, void *value, + * void *callback_ctx); + */ + callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1]; + + callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY; + __mark_reg_known_zero(&callee->regs[BPF_REG_2]); + callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr; + + callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE; + __mark_reg_known_zero(&callee->regs[BPF_REG_3]); + callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr; + + /* pointer to stack or null */ + callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3]; + + /* unused */ + __mark_reg_not_init(env, &callee->regs[BPF_REG_5]); + return 0; +} + static int set_callee_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, int insn_idx)