From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Daniel Borkmann <daniel@iogearbox.net>,
"Paul E . McKenney" <paulmck@kernel.org>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH v4 bpf-next 1/5] bpf: Remove redundant synchronize_rcu.
Date: Mon, 29 Jun 2020 17:58:38 -0700 [thread overview]
Message-ID: <CAEf4BzaLJ619mcN9pBQkupkJOcFfXWiuM8oy0Qjezy65Rpd_vA@mail.gmail.com> (raw)
In-Reply-To: <20200630003441.42616-2-alexei.starovoitov@gmail.com>
On Mon, Jun 29, 2020 at 5:35 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> From: Alexei Starovoitov <ast@kernel.org>
>
> bpf_free_used_maps() or close(map_fd) will trigger map_free callback.
> bpf_free_used_maps() is called after bpf prog is no longer executing:
> bpf_prog_put->call_rcu->bpf_prog_free->bpf_free_used_maps.
> Hence there is no need to call synchronize_rcu() to protect map elements.
>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---
Seems correct. And nice that maps don't have to care about this anymore.
Acked-by: Andrii Nakryiko <andriin@fb.com>
> kernel/bpf/arraymap.c | 9 ---------
> kernel/bpf/hashtab.c | 8 +++-----
> kernel/bpf/lpm_trie.c | 5 -----
> kernel/bpf/queue_stack_maps.c | 7 -------
> kernel/bpf/reuseport_array.c | 2 --
> kernel/bpf/ringbuf.c | 7 -------
> kernel/bpf/stackmap.c | 3 ---
> 7 files changed, 3 insertions(+), 38 deletions(-)
>
next prev parent reply other threads:[~2020-06-30 0:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 0:34 [PATCH v4 bpf-next 0/5] bpf: Introduce minimal support for sleepable progs Alexei Starovoitov
2020-06-30 0:34 ` [PATCH v4 bpf-next 1/5] bpf: Remove redundant synchronize_rcu Alexei Starovoitov
2020-06-30 0:58 ` Andrii Nakryiko [this message]
2020-06-30 1:08 ` Andrii Nakryiko
2020-06-30 2:56 ` Alexei Starovoitov
2020-06-30 3:31 ` Andrii Nakryiko
2020-06-30 0:34 ` [PATCH v4 bpf-next 2/5] bpf: Introduce sleepable BPF programs Alexei Starovoitov
2020-06-30 1:15 ` Andrii Nakryiko
2020-06-30 3:03 ` Alexei Starovoitov
2020-06-30 0:34 ` [PATCH v4 bpf-next 3/5] bpf: Add bpf_copy_from_user() helper Alexei Starovoitov
2020-06-30 1:18 ` Andrii Nakryiko
2020-06-30 0:34 ` [PATCH v4 bpf-next 4/5] libbpf: support sleepable progs Alexei Starovoitov
2020-06-30 0:34 ` [PATCH v4 bpf-next 5/5] selftests/bpf: Add sleepable tests Alexei Starovoitov
2020-06-30 1:25 ` Andrii Nakryiko
2020-06-30 3:06 ` Alexei Starovoitov
2020-06-30 3:34 ` Andrii Nakryiko
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