Author: gnn
Date: Mon Nov 18 22:58:14 2013
New Revision: 258328
URL: http://svnweb.freebsd.org/changeset/base/258328

Log:
  Allow ethernet drivers to pass in packets connected via the nextpkt pointer.
  Handling packets in this way allows drivers to amortize work during packet 
reception.
  
  Submitted by: Vijay Singh
  Sponsored by: NetApp

Modified:
  head/sys/net/if_ethersubr.c

Modified: head/sys/net/if_ethersubr.c
==============================================================================
--- head/sys/net/if_ethersubr.c Mon Nov 18 22:55:50 2013        (r258327)
+++ head/sys/net/if_ethersubr.c Mon Nov 18 22:58:14 2013        (r258328)
@@ -708,13 +708,25 @@ static void
 ether_input(struct ifnet *ifp, struct mbuf *m)
 {
 
+       struct mbuf *mn;
+
        /*
-        * We will rely on rcvif being set properly in the deferred context,
-        * so assert it is correct here.
+        * The drivers are allowed to pass in a chain of packets linked with
+        * m_nextpkt. We split them up into separate packets here and pass
+        * them up. This allows the drivers to amortize the receive lock.
         */
-       KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", __func__));
+       while (m) {
+               mn = m->m_nextpkt;
+               m->m_nextpkt = NULL;
 
-       netisr_dispatch(NETISR_ETHER, m);
+               /*
+                * We will rely on rcvif being set properly in the deferred 
context,
+                * so assert it is correct here.
+                */
+               KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", 
__func__));
+               netisr_dispatch(NETISR_ETHER, m);
+               m = mn;
+       }
 }
 
 /*
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