Re: VIRTIO_NET_HDR_F_RSC_INFO in virtio-net vs headers update

[Jason Wang <jasowang@redhat.com>]

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On 2020/4/27 下午3:33, Cornelia Huck wrote:
> Hi,
>
> I'm currently trying to prepare a linux-headers update to 5.7-rc3,
> which adds the definition of VIRTIO_NET_HDR_F_RSC_INFO.
>
> Unfortunately, this breaks the build of virtio-net, because now
> virtio_net_rsc_ext_num_{packets,dupacks} are undefined (they are
> guarded by existence of VIRTIO_NET_HDR_F_RSC_INFO).
>
> What is the right way to fix this? Remove the constants that are now
> provided by the header and keep the definitions of
> virtio_net_rsc_ext_num_{packets,dupacks}?


We probably need to add a version of the above function when 
VIRTIO_NET_HDR_F_RSC_INFO is defined as attached.

But I fail to understand why we need a fallback when 
VIRTIO_NET_HDR_F_RSC_INFO is not defined.

Thanks


>
> [I'd like to queue a headers update as soon as possible, as the whole
> s390 protected virt stuff depends on it...]
>
>

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From 915144149cfef1c056ae3b96dfb714a2bd483759 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Mon, 27 Apr 2020 16:38:51 +0800
Subject: [PATCH]

---
 hw/net/virtio-net.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index e5bf670c3f..dd671bcc0d 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -171,6 +171,20 @@ static inline __virtio16 *virtio_net_rsc_ext_num_dupacks(
     return &hdr->csum_offset;
 }
 
+#else
+
+static inline __virtio16 *virtio_net_rsc_ext_num_packets(
+    struct virtio_net_hdr *hdr)
+{
+    return &hdr->segments;
+}
+
+static inline __virtio16 *virtio_net_rsc_ext_num_dupacks(
+    struct virtio_net_hdr *hdr)
+{
+    return &hdr->dup_acks;
+}
+
 #endif
 
 static VirtIOFeature feature_sizes[] = {
-- 
2.20.1