linux-kernel - Re: [PATCH 1/1] tg3: fix meaningless hw_stats reading after tg3_halt memset 0 hw

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Message-ID: <eb6f9052-88fc-6b90-2278-88df3b3cccd8@gmail.com>
Date:   Sun, 29 Apr 2018 14:43:19 +0800
From:   Zumeng Chen <zumeng.chen@...il.com>
To:     Michael Chan <michael.chan@...adcom.com>
Cc:     Netdev <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Siva Reddy Kallam <siva.kallam@...adcom.com>,
        "michael.chan@...adcom.com" <mchan@...adcom.com>,
        "prashant.sreedharan@...adcom.com" <prashant@...adcom.com>,
        David Miller <davem@...emloft.net>
Subject: Re: [PATCH 1/1] tg3: fix meaningless hw_stats reading after tg3_halt
 memset 0 hw_stats

On 2018年04月29日 02:36, Michael Chan wrote:
> On Fri, Apr 27, 2018 at 8:15 PM, Zumeng Chen <zumeng.chen@...il.com> wrote:
>
>> diff --git a/drivers/net/ethernet/broadcom/tg3.h b/drivers/net/ethernet/broadcom/tg3.h
>> index 3b5e98e..6727d93 100644
>> --- a/drivers/net/ethernet/broadcom/tg3.h
>> +++ b/drivers/net/ethernet/broadcom/tg3.h
>> @@ -3352,6 +3352,7 @@ struct tg3 {
>>          struct pci_dev                  *pdev_peer;
>>
>>          struct tg3_hw_stats             *hw_stats;
>> +       bool                            hw_stats_flag;
> You can just add another bit to enum TG3_FLAGS for this purpose.

Right, it's a good idea, I didn't notice it, I'll send V2 with that later.

>
> While this scheme will probably work, I think a better and more
> elegant way to fix this is to use RCU.

IMHO, RCU is not necessary for this simple two consumers, and no 
frequent ops
on tg3_halt, plus no new locker involved either.

Cheers,
Zumeng
>
>>          dma_addr_t                      stats_mapping;
>>          struct work_struct              reset_task;
>>
>> --
>> 2.9.3
>>