netdev - Re: Fwd: u32 ht filters

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Message-ID: <20180208073846.GA2041@nanopsycho>
Date:   Thu, 8 Feb 2018 08:38:46 +0100
From:   Jiri Pirko <jiri@...nulli.us>
To:     Cong Wang <xiyou.wangcong@...il.com>
Cc:     Jiri Pirko <jiri@...lanox.com>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Paweł Staszewski <pstaszewski@...are.pl>
Subject: Re: Fwd: u32 ht filters

Thu, Feb 08, 2018 at 12:08:36AM CET, xiyou.wangcong@...il.com wrote:
>On Tue, Feb 6, 2018 at 11:01 PM, Jiri Pirko <jiri@...nulli.us> wrote:
>> Wed, Feb 07, 2018 at 06:09:15AM CET, xiyou.wangcong@...il.com wrote:
>>>Hi, Jiri
>>>
>>>Your  commit 7fa9d974f3c2a016b9accb18f4ee2ed2a738585c
>>>breaks the tc script by Paweł. Please find below for details.
>>
>> Did you do the bisection?
>> The commit just uses block struct instead of q, but since they
>> are in 1:1 relation, that should be equvivalent. So basically you still
>> have per-qdisc hashtables for u32.
>
>Well, at least the following fixes the problem here. But I am not sure
>if it is expected too for shared block among multiple qdiscs.

For shared block, block->q is null.


>
>
>@@ -338,7 +330,7 @@ static struct hlist_head *tc_u_common_hash;
>
> static unsigned int tc_u_hash(const struct tcf_proto *tp)
> {
>-       return hash_ptr(tp->chain->block, U32_HASH_SHIFT);
>+       return hash_ptr(tp->chain->block->q, U32_HASH_SHIFT);
> }
>
> static struct tc_u_common *tc_u_common_find(const struct tcf_proto *tp)
>@@ -348,7 +340,7 @@ static struct tc_u_common *tc_u_common_find(const
>struct tcf_proto *tp)
>
>        h = tc_u_hash(tp);
>        hlist_for_each_entry(tc, &tc_u_common_hash[h], hnode) {
>-               if (tc->block == tp->chain->block)
>+               if (tc->block->q == tp->chain->block->q)

:O I don't get it. tc->block is pointer, tc->block->q is pointer. And
they are different at the same time for non-shared block.


>                        return tc;
>        }
>        return NULL;