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From: "Justin T. Gibbs" <gibbs@FreeBSD.org>
Date: Sat, 29 Jan 2011 02:36:45 +0000 (UTC)
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Subject: svn commit: r218056 - head/sys/dev/xen/netfront
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Author: gibbs
Date: Sat Jan 29 02:36:45 2011
New Revision: 218056
URL: http://svn.freebsd.org/changeset/base/218056

Log:
  Fix bug in the netfront driver that caused excessive packet drops during
  receive processing.
  
  Remove unnecessary restrictions on the mbuf chain length built during an
  LRO receive.  This restriction was copied from the Linux netfront driver
  where the LRO implementation cannot handle more than 18 discontinuities.
  The FreeBSD implementation has no such restriction.
  
  MFC after: 1 week

Modified:
  head/sys/dev/xen/netfront/netfront.c

Modified: head/sys/dev/xen/netfront/netfront.c
==============================================================================
--- head/sys/dev/xen/netfront/netfront.c	Sat Jan 29 00:53:58 2011	(r218055)
+++ head/sys/dev/xen/netfront/netfront.c	Sat Jan 29 02:36:45 2011	(r218056)
@@ -1273,7 +1273,6 @@ xennet_get_responses(struct netfront_inf
 	struct mbuf *m, *m0, *m_prev;
 	grant_ref_t ref = xennet_get_rx_ref(np, *cons);
 	RING_IDX ref_cons = *cons;
-	int max = 5 /* MAX_TX_REQ_FRAGS + (rx->status <= RX_COPY_THRESHOLD) */;
 	int frags = 1;
 	int err = 0;
 	u_long ret;
@@ -1416,20 +1415,10 @@ next_skip_queue:
 		frags++;
 	}
 	*list = m0;
-
-	if (unlikely(frags > max)) {
-		if (net_ratelimit())
-			WPRINTK("Too many frags\n");
-		printf("%s: too many frags %d > max %d\n", __func__, frags,
-		       max);
-		err = E2BIG;
-	}
-
 	*cons += frags;
-
 	*pages_flipped_p = pages_flipped;
 
-	return err;
+	return (err);
 }
 
 static void