netdev - Re: [PATCH net-next v4 10/17] net: sched: refactor tp insert/delete for concurrent execution

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <vbfimxhqr7z.fsf@mellanox.com>
Date:   Mon, 18 Feb 2019 11:19:21 +0000
From:   Vlad Buslov <vladbu@...lanox.com>
To:     Cong Wang <xiyou.wangcong@...il.com>
CC:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>,
        David Miller <davem@...emloft.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: Re: [PATCH net-next v4 10/17] net: sched: refactor tp insert/delete
 for concurrent execution


On Fri 15 Feb 2019 at 23:17, Cong Wang <xiyou.wangcong@...il.com> wrote:
> On Mon, Feb 11, 2019 at 12:56 AM Vlad Buslov <vladbu@...lanox.com> wrote:
>> +static bool tcf_proto_is_empty(struct tcf_proto *tp)
>> +{
>> +       struct tcf_walker walker = { .fn = walker_noop, };
>> +
>> +       if (tp->ops->walk) {
>> +               tp->ops->walk(tp, &walker);
>> +               return !walker.stop;
>> +       }
>> +       return true;
>> +}
>> +
>> +static bool tcf_proto_check_delete(struct tcf_proto *tp)
>> +{
>> +       spin_lock(&tp->lock);
>> +       if (tcf_proto_is_empty(tp))
>> +               tp->deleting = true;
>> +       spin_unlock(&tp->lock);
>> +       return tp->deleting;
>
> If you use this spinlock for walking each tp data structure,
> why it is not needed for adding to/deleting filters from each
> tp?

This lock is intended to be used by unlocked classifiers and I use it in
my following flower patch set extensively. Classifiers that do not set
'unlocked' flag continue to rely on rtnl lock for synchronization.