netdev - Re: [PATCH RFC net-next] virtio_net: Relax queue requirement for using XDP

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: <5861350a-a0f6-9a74-e06d-4b7fd688e5e7@gmail.com>
Date:   Tue, 25 Feb 2020 21:35:04 -0700
From:   David Ahern <dsahern@...il.com>
To:     Jason Wang <jasowang@...hat.com>,
        David Ahern <dahern@...italocean.com>,
        David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org,
        "Michael S . Tsirkin" <mst@...hat.com>
Subject: Re: [PATCH RFC net-next] virtio_net: Relax queue requirement for
 using XDP

On 2/25/20 8:52 PM, Jason Wang wrote:
> 
> On 2020/2/26 上午11:34, David Ahern wrote:
>> On 2/25/20 8:29 PM, Jason Wang wrote:
>>> TAP uses spinlock for XDP_TX.
>> code reference? I can not find that.
>>
> 
> In tun_xdp_xmit(), ptr_ring is synchronized through producer_lock.
> 

thanks. I was confused by the tap comment when it is the tun code.

So you mean a spinlock around virtnet_xdp_xmit for XDP_TX:

+                       if (!vi->can_do_xdp_tx)
+                               spin_lock(&vi->xdp_tx_lock);
                        err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
+                       if (!vi->can_do_xdp_tx)
+                               spin_unlock(&vi->xdp_tx_lock);