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Date: Fri, 8 Mar 2024 20:08:01 +0800
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Subject: Re: [PATCH net-next] net/packet: Add getsockopt support for
 PACKET_COPY_THRESH
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>, davem@davemloft.net,
 edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <AM6PR03MB5848595A20BB5D958C2D9DE299272@AM6PR03MB5848.eurprd03.prod.outlook.com>
 <65eaf9e336d07_133b25294db@willemb.c.googlers.com.notmuch>
From: Juntong Deng <juntong.deng@outlook.com>
In-Reply-To: <65eaf9e336d07_133b25294db@willemb.c.googlers.com.notmuch>
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On 2024/3/8 19:43, Willem de Bruijn wrote:
> Juntong Deng wrote:
>> Currently getsockopt does not support PACKET_COPY_THRESH,
>> and we are unable to get the value of PACKET_COPY_THRESH
>> socket option through getsockopt.
>>
>> This patch adds getsockopt support for PACKET_COPY_THRESH.
>>
>> Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
>> ---
>>   net/packet/af_packet.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
>> index 0db31ca4982d..65042edd1a97 100644
>> --- a/net/packet/af_packet.c
>> +++ b/net/packet/af_packet.c
>> @@ -4090,6 +4090,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
>>   	case PACKET_VNET_HDR_SZ:
>>   		val = READ_ONCE(po->vnet_hdr_sz);
>>   		break;
>> +	case PACKET_COPY_THRESH:
>> +		val = pkt_sk(sk)->copy_thresh;
>> +		break;
> 
> This is probably a good opportunity to use READ_ONCE/WRITE_ONCE for
> this variable that can be modified and read concurrently.
> 
> Alternatively I can fix up all three locations in a follow-on patch.
> 
> No concerns with adding the getsockopt itself.
> 
>>   	case PACKET_VERSION:
>>   		val = po->tp_version;
>>   		break;
>> -- 
>> 2.39.2
>>
> 
> 

Thanks for reviewing.

So, do I need to send PATCH V2 to add READ_ONCE?

Or do you want you to use a follow-on patch to fix all three locations 
at once?