Re: [PATCH] GRE: Use IS_ERR_OR_NULL in gre_gso_segment

[Eric Dumazet <eric.dumazet@gmail.com>]

On Thu, 2013-04-25 at 17:11 +0800, Herbert Xu wrote:

> In any case, returning an error in this case makes little sense
> because when we return NULL it is precisely because the packet is
> well-formed and ready for direct processing by the hardware which
> will perform GSO instead of us.
> 
> The reason this dichotomy exists is because we've reused the
> normal software GSO path to do header verification for hardware
> GSO.
> 

OK, then current code is fine. Comments will save future 'cleanups'.

diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c
index d2d5a99..ddf72eb 100644
--- a/net/ipv4/gre.c
+++ b/net/ipv4/gre.c
@@ -168,7 +168,11 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	/* segment inner packet. */
 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
 	segs = skb_mac_gso_segment(skb, enc_features);
-	if (!segs || IS_ERR(segs))
+	/* if no segmentation is needed, we're done */
+	if (!segs)
+		goto out;
+	/* if an error happened during segmentation, we're done */
+	if (IS_ERR(segs))
 		goto out;
 
 	skb = segs;