netdev - [net-next PATCH v3 1/6] udp: Record gso_segs when supporting UDP segmentation offload

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Message-ID: <20180507180821.3486.68488.stgit@localhost.localdomain>
Date:   Mon, 07 May 2018 11:08:22 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     netdev@...r.kernel.org, willemb@...gle.com, davem@...emloft.net
Subject: [net-next PATCH v3 1/6] udp: Record gso_segs when supporting UDP
 segmentation offload

From: Alexander Duyck <alexander.h.duyck@...el.com>

We need to record the number of segments that will be generated when this
frame is segmented. The expectation is that if gso_size is set then
gso_segs is set as well. Without this some drivers such as ixgbe get
confused if they attempt to offload this as they record 0 segments for the
entire packet instead of the correct value.

Reviewed-by: Eric Dumazet <edumazet@...gle.com>
Acked-by: Willem de Bruijn <willemb@...gle.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
 net/ipv4/udp.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index dd3102a37ef9..e07db83b311e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -793,6 +793,8 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
 
 		skb_shinfo(skb)->gso_size = cork->gso_size;
 		skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
+		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(uh),
+							 cork->gso_size);
 		goto csum_partial;
 	}