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bpf: btf: add pretty print for hash/lru_hash maps 

Commit a26ca7c982 ("bpf: btf: Add pretty print support to
the basic arraymap") added pretty print support to array map.
This patch adds pretty print for hash and lru_hash maps.
The following example shows the pretty-print result of
a pinned hashmap:

    struct map_value {
            int count_a;
            int count_b;
    };

    cat /sys/fs/bpf/pinned_hash_map:

    87907: {87907,87908}
    57354: {37354,57355}
    76625: {76625,76626}
    ...

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
hifive-unleashed-5.1
Yonghong Song 2018-08-09 08:55:20 -07:00 committed by Daniel Borkmann
parent dc1508a579
commit 699c86d6ec
1 changed files with 44 additions and 0 deletions
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44
kernel/bpf/hashtab.c
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@ -11,9 +11,11 @@
* General Public License for more details.
*/
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/jhash.h>
#include <linux/filter.h>
#include <linux/rculist_nulls.h>
#include <uapi/linux/btf.h>
#include "percpu_freelist.h"
#include "bpf_lru_list.h"
#include "map_in_map.h"
@ -1162,6 +1164,44 @@ static void htab_map_free(struct bpf_map *map)
kfree(htab);
}
static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
void *value;
rcu_read_lock();
value = htab_map_lookup_elem(map, key);
if (!value) {
rcu_read_unlock();
return;
}
btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
seq_puts(m, ": ");
btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
seq_puts(m, "\n");
rcu_read_unlock();
}
static int htab_map_check_btf(const struct bpf_map *map, const struct btf *btf,
u32 btf_key_id, u32 btf_value_id)
{
const struct btf_type *key_type, *value_type;
u32 key_size, value_size;
key_type = btf_type_id_size(btf, &btf_key_id, &key_size);
if (!key_type || key_size != map->key_size)
return -EINVAL;
value_type = btf_type_id_size(btf, &btf_value_id, &value_size);
if (!value_type || value_size != map->value_size)
return -EINVAL;
return 0;
}
const struct bpf_map_ops htab_map_ops = {
.map_alloc_check = htab_map_alloc_check,
.map_alloc = htab_map_alloc,
@ -1171,6 +1211,8 @@ const struct bpf_map_ops htab_map_ops = {
.map_update_elem = htab_map_update_elem,
.map_delete_elem = htab_map_delete_elem,
.map_gen_lookup = htab_map_gen_lookup,
.map_seq_show_elem = htab_map_seq_show_elem,
.map_check_btf = htab_map_check_btf,
};
const struct bpf_map_ops htab_lru_map_ops = {
@ -1182,6 +1224,8 @@ const struct bpf_map_ops htab_lru_map_ops = {
.map_update_elem = htab_lru_map_update_elem,
.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_check_btf = htab_map_check_btf,
};
/* Called from eBPF program */