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From: Stephen Hemminger <stephen@networkplumber.org>
To: Yunjian Wang <wangyunjian@huawei.com>
Cc: <dev@dpdk.org>, <maxime.coquelin@redhat.com>,
	<chenbox@nvidia.com>, <jerry.lilijun@huawei.com>,
	<xiawei40@huawei.com>, <wangzengyuan@huawei.com>,
	<stable@dpdk.org>
Subject: Re: [PATCH 1/1] vhost: fix a double fetch when dequeue offloading
Date: Fri, 20 Dec 2024 08:35:46 -0800	[thread overview]
Message-ID: <20241220083546.4b5ba9c9@hermes.local> (raw)
In-Reply-To: <91dc12662805a3867413940f856ba9454b91c579.1734588243.git.wangyunjian@huawei.com>

On Thu, 19 Dec 2024 14:38:28 +0800
Yunjian Wang <wangyunjian@huawei.com> wrote:

> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 69901ab3b5..5c40ae7069 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -2914,10 +2914,12 @@ desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  			 * in a contiguous virtual area.
>  			 */
>  			copy_vnet_hdr_from_desc(&tmp_hdr, buf_vec);
> -			hdr = &tmp_hdr;
>  		} else {
> -			hdr = (struct virtio_net_hdr *)((uintptr_t)buf_vec[0].buf_addr);
> +			rte_memcpy((void *)(uintptr_t)&tmp_hdr,
> +				(void *)(uintptr_t)buf_vec[0].buf_addr,
> +				sizeof(struct virtio_net_hdr));
>  		}
> +		hdr = &tmp_hdr;

Since this if block is just an optimization of the case where vnet header
is contiguous why not just always use copy_vnet_hdr_from_desc? and inline it?

      parent reply	other threads:[~2024-12-20 16:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-19  6:38 Yunjian Wang
2024-12-19  8:24 ` David Marchand
2024-12-19 11:02   ` Wangyunjian(wangyunjian,TongTu)
2024-12-19 16:15 ` Stephen Hemminger
2024-12-20  2:17   ` Wangyunjian(wangyunjian,TongTu)
2024-12-20  4:59     ` Stephen Hemminger
2024-12-20  3:49 ` [PATCH v2 " Yunjian Wang
2024-12-20 17:10   ` Stephen Hemminger
2024-12-20 16:35 ` Stephen Hemminger [this message]

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