[PATCH net-next] gro: introduce gro_mac_header_len
From: Eric Dumazet <hidden>
Date: 2012-02-06 16:27:07
Also in:
linux-rdma
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2012-02-06 · Re: [PATCH net-next] gro: introduce gro_mac_header_len · David Miller <hidden>
- 2012-02-06 · Re: [PATCH net-next] gro: introduce gro_mac_header_len · Or Gerlitz <hidden>
Shlomo Pongratz reported GRO L2 header check was suited for Ethernet only, and failed on IB/ipoib traffic. He provided a patch faking a zeroed header to let GRO aggregates frames. Roland Dreier, Herbert Xu, and others suggested we change GRO L2 header check to be more generic. This patch introduces a new netdevice field, gro_mac_header_len, giving L2 header length, default to ETH_HLEN (14 bytes) A device setup function can override this default value. __napi_gro_receive() has special handling for the common case (Ethernet) to avoid a memcmp() call and use an inline optimized function instead. Signed-off-by: Eric Dumazet <redacted> Reported-by: Shlomo Pongratz <shlomop-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Cc: Roland Dreier <redacted> Cc: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Cc: Herbert Xu <redacted> --- include/linux/netdevice.h | 1 + net/core/dev.c | 11 +++++++++-- 2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0eac07c..d17192b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -1095,6 +1095,7 @@ struct net_device { unsigned int mtu; /* interface MTU value */ unsigned short type; /* interface hardware type */ unsigned short hard_header_len; /* hardware hdr length */ + unsigned int gro_mac_header_len; /* extra head- and tailroom the hardware may need, but not in all cases * can this be guaranteed, especially tailroom. Some cases also use
diff --git a/net/core/dev.c b/net/core/dev.c
index f124947..0b43939 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -3491,14 +3491,20 @@ static inline gro_result_t __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) { struct sk_buff *p; + unsigned int maclen = skb->dev->gro_mac_header_len; for (p = napi->gro_list; p; p = p->next) { unsigned long diffs; diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; diffs |= p->vlan_tci ^ skb->vlan_tci; - diffs |= compare_ether_header(skb_mac_header(p), - skb_gro_mac_header(skb)); + if (maclen == ETH_HLEN) + diffs |= compare_ether_header(skb_mac_header(p), + skb_gro_mac_header(skb)); + else if (!diffs) + diffs = memcmp(skb_mac_header(p), + skb_gro_mac_header(skb), + maclen); NAPI_GRO_CB(p)->same_flow = !diffs; NAPI_GRO_CB(p)->flush = 0; }
@@ -5962,6 +5968,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, INIT_LIST_HEAD(&dev->unreg_list); INIT_LIST_HEAD(&dev->link_watch_list); dev->priv_flags = IFF_XMIT_DST_RELEASE; + dev->gro_mac_header_len = ETH_HLEN; setup(dev); dev->num_tx_queues = txqs; --
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