netdev - Re: gso: Attempt to handle mega-GRO packets

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Message-ID: <20131106123900.GA20259@gondor.apana.org.au>
Date:	Wed, 6 Nov 2013 20:39:00 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Ben Hutchings <bhutchings@...arflare.com>,
	David Miller <davem@...emloft.net>,
	christoph.paasch@...ouvain.be, netdev@...r.kernel.org,
	hkchu@...gle.com, mwdalton@...gle.com
Subject: Re: gso: Attempt to handle mega-GRO packets

On Wed, Nov 06, 2013 at 09:30:38AM +0800, Herbert Xu wrote:
> Here is a totally untested patch that tries to trivially process
> these new frags + frag_list skbs.  It should actually be trivial
> to make this generate TSO packets by just adding a gso_ok check
> and short-circuit.

That patch obviously didn't have a chance of working since I missed
a continue.

Here is a better version.

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3735fad..409bd9b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2816,7 +2816,31 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 			hsize = len;
 
 		if (!hsize && i >= nfrags) {
-			BUG_ON(fskb->len != len);
+			if (fskb->len != len) {
+				SKB_FRAG_ASSERT(fskb);
+
+				nskb = skb_segment(fskb, features);
+
+				err = PTR_ERR(nskb);
+				if (IS_ERR(nskb))
+					goto err;
+				err = -ENOMEM;
+
+				if (segs)
+					tail->next = nskb;
+				else
+					segs = nskb;
+
+				tail = nskb;
+				while (tail->next)
+					tail = tail->next;
+
+				BUG_ON(fskb->next && tail->len != len);
+
+				len = fskb->len;
+				fskb = fskb->next;
+				continue;
+			}
 
 			pos += len;
 			nskb = skb_clone(fskb, GFP_ATOMIC);

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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