Re: [PATCH 5/8] xen/netfront: read response from backend only once
From: Jan Beulich <hidden>
Date: 2021-05-17 14:24:05
Also in:
lkml, xen-devel
On 13.05.2021 12:02, Juergen Gross wrote:
In order to avoid problems in case the backend is modifying a response on the ring page while the frontend has already seen it, just read the response into a local buffer in one go and then operate on that buffer only. Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <redacted> with one remark:
quoted hunk ↗ jump to hunk
@@ -830,24 +830,22 @@ static int xennet_get_extras(struct netfront_queue *queue, break; } - extra = (struct xen_netif_extra_info *) - RING_GET_RESPONSE(&queue->rx, ++cons); + RING_COPY_RESPONSE(&queue->rx, ++cons, &extra); - if (unlikely(!extra->type || - extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) { + if (unlikely(!extra.type || + extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { if (net_ratelimit()) dev_warn(dev, "Invalid extra type: %d\n", - extra->type); + extra.type); err = -EINVAL; } else { - memcpy(&extras[extra->type - 1], extra, - sizeof(*extra)); + memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
Maybe take the opportunity and switch to (type safe) structure assignment? Jan