linux-kernel - Re: [PATCH net-next 07/11] tuntap: move XDP flushing out of tun_do

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Message-ID: <25e6c109-69bd-ca10-3322-0e3d3b23f5dd@redhat.com>
Date:   Fri, 7 Sep 2018 11:31:37 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH net-next 07/11] tuntap: move XDP flushing out of
 tun_do_xdp()



On 2018年09月07日 01:48, Michael S. Tsirkin wrote:
> On Thu, Sep 06, 2018 at 12:05:22PM +0800, Jason Wang wrote:
>> This will allow adding batch flushing on top.
>>
>> Signed-off-by: Jason Wang <jasowang@...hat.com>
>> ---
>>   drivers/net/tun.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
>> index 21b125020b3b..ff1cbf3ebd50 100644
>> --- a/drivers/net/tun.c
>> +++ b/drivers/net/tun.c
>> @@ -1646,7 +1646,6 @@ static u32 tun_do_xdp(struct tun_struct *tun,
>>   	switch (act) {
>>   	case XDP_REDIRECT:
>>   		*err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
>> -		xdp_do_flush_map();
>>   		if (*err)
>>   			break;
>>   		goto out;
>> @@ -1735,6 +1734,9 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
>>   		act = tun_do_xdp(tun, tfile, xdp_prog, &xdp, &err);
>>   		if (err)
>>   			goto err_xdp;
>> +
>> +		if (act == XDP_REDIRECT)
>> +			xdp_do_flush_map();
>>   		if (act != XDP_PASS)
>>   			goto out;
> At this point the switch statement which used to contain all XDP things
> seems to be gone completely. Just rewrite with a bunch of if statements
> and all xdp handling spread out to where it makes sense?

But tun_do_xdp() will be reused in the batching path.

Thanks

>
>> -- 
>> 2.17.1