[dpdk-stable] [PATCH] vhost: fix packed ring descriptor update in async enqueue

[Maxime Coquelin]

On 11/4/21 11:19, Jiayu Hu wrote:
> For the packet using multiple descriptors, the flag of first
> descriptor cannot be updated until finishing updating the flag
> of remaining descriptors. However, if the packet's descriptor
> index is wrapped, the first descriptor's flag is updated earlier
> than the others.

The commit message is ambiguous IMHO, it is not clear whether it
describes the bug or the fix. I understand it describes the problem,
as the first descriptor flags always have to be updated last, but it
please reword it to make it clear what iu the issue, and how this patch
fixes it.

> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: stable at dpdk.org

If you think it is worth backporting it to stable, please take care of
preparing the backport as I suspect it will not apply cleanly.

> Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
> ---
>   lib/vhost/virtio_net.c | 122 ++++++++++++++++++-----------------------
>   1 file changed, 54 insertions(+), 68 deletions(-)
>