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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 <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226204927.3885020-1-yhs@fb.com
This commit is contained in:
Yonghong Song 2021-02-26 12:49:27 -08:00 committed by Menglong Dong
parent d814bf2895
commit 57dc4fa63e
3 changed files with 89 additions and 0 deletions
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4
include/linux/bpf.h
View File

@ -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,

58
kernel/bpf/hashtab.c
View File

@ -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,

27
kernel/bpf/verifier.c
View File

@ -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)