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bpf: Fix seq_show for BPF_MAP_TYPE_STRUCT_OPS 

Instead of using bpf_struct_ops_map_lookup_elem() which is
not implemented, bpf_struct_ops_map_seq_show_elem() should
also use bpf_struct_ops_map_sys_lookup_elem() which does
an inplace update to the value.  The change allocates
a value to pass to bpf_struct_ops_map_sys_lookup_elem().

[root@arch-fb-vm1 bpf]# cat /sys/fs/bpf/dctcp
{{{1}},BPF_STRUCT_OPS_STATE_INUSE,{{00000000df93eebc,00000000df93eebc},0,2, ...

Fixes: 85d33df357 ("bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200114072647.3188298-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau 2020-01-13 23:26:47 -08:00 committed by Alexei Starovoitov
parent 6dd42aa17f
commit 3b4130418f
1 changed files with 10 additions and 4 deletions
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14
kernel/bpf/bpf_struct_ops.c
View File

@ -496,14 +496,20 @@ static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
void *value;
int err;
value = bpf_struct_ops_map_lookup_elem(map, key);
value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
if (!value)
return;
btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
value, m);
seq_puts(m, "\n");
err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
if (!err) {
btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
value, m);
seq_puts(m, "\n");
}
kfree(value);
}
static void bpf_struct_ops_map_free(struct bpf_map *map)