From: Eric Dumazet <eric.dumazet@gmail.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Ming Lei <tom.leiming@gmail.com>,
FB Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH v2 net-next 3/4] bpf: bpf_htab: Add syscall to iterate percpu value of a key
Date: Tue, 12 Jan 2016 18:24:56 -0800 [thread overview]
Message-ID: <1452651896.1223.45.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <1452586852-1575604-4-git-send-email-kafai@fb.com>
On Tue, 2016-01-12 at 00:20 -0800, Martin KaFai Lau wrote:
> Add map_lookup_percpu_elem() syscall to lookup value
> of a particular CPU.
...
> +static int map_lookup_percpu_elem(union bpf_attr *attr)
> +{
> + void __user *ukey = u64_to_ptr(attr->key);
> + void __user *uvalue = u64_to_ptr(attr->value);
> + u32 __user ucpu = attr->cpu;
> + int ufd = attr->map_fd;
> + struct percpu_map_value_info value_info;
> + struct bpf_map *map;
> + void *key, *value;
> + struct fd f;
> + int err;
> +
> + if (CHECK_ATTR(BPF_MAP_LOOKUP_PERCPU_ELEM) ||
> + ucpu >= num_possible_cpus())
> + return -EINVAL;
Arg, a num_possible_cpus() wrong call.
You probably want to use (ucpu >= nr_cpu_ids)
hint : You can have hosts with 2 possibles cpus, CPU0 and CPU2
So the userland loop in your changelog is wrong.
next prev parent reply other threads:[~2016-01-13 2:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 8:20 [PATCH v2 net-next 0/4] bpf: bpf_htab: Add BPF_MAP_TYPE_PERCPU_HASH Martin KaFai Lau
2016-01-12 8:20 ` [PATCH v2 net-next 1/4] bpf: bpf_htab: Refactor some htab_elem logic Martin KaFai Lau
2016-01-12 8:20 ` [PATCH v2 net-next 2/4] bpf: bpf_htab: Add BPF_MAP_TYPE_PERCPU_HASH Martin KaFai Lau
2016-01-12 8:20 ` [PATCH v2 net-next 3/4] bpf: bpf_htab: Add syscall to iterate percpu value of a key Martin KaFai Lau
2016-01-13 2:24 ` Eric Dumazet [this message]
2016-01-13 2:42 ` Ming Lei
2016-01-13 5:23 ` Alexei Starovoitov
2016-01-13 15:43 ` Ming Lei
2016-01-14 1:24 ` Alexei Starovoitov
2016-01-14 3:23 ` Ming Lei
2016-01-12 8:20 ` [PATCH v2 net-next 4/4] bpf: bpf_htab: Test for BPF_MAP_TYPE_PERCPU_HASH Martin KaFai Lau
2016-01-12 21:45 ` [PATCH v2 net-next 0/4] bpf: bpf_htab: Add BPF_MAP_TYPE_PERCPU_HASH David Miller
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