Virtualized SINIC fixes

dev/pktfifo.hh:
    we can't modify i because it's used further down to remove
    the packet from the fifo.  Instead, copy the iterator and
    modify that to get the previous packet.
dev/sinic.cc:
    - don't change the transmit state and kick the machine unless
    we're at the head of the txList.
    - add a couple of debugging statements to figure out how far
    along we've gotten in processing a packet.
    - assert that the current tx vnic has something to do when
    we start processing the state machine.

--HG--
extra : convert_revision : 588fe2c7d810be0e3d8d39c5cc0ec8a72119517e

1 files changed, 4 insertions, 2 deletions

diff --git a/dev/pktfifo.hh b/dev/pktfifo.hh
index 61e4ead1b..e63fd291f 100644
--- a/dev/pktfifo.hh
+++ b/dev/pktfifo.hh
@@ -113,8 +113,10 @@ class PacketFifo
     {
         PacketPtr &packet = *i;
         if (i != fifo.begin()) {
-            --i;
-            (*i)->slack += packet->length;
+            iterator prev = i;
+            --prev;
+            assert(prev != fifo.end());
+            (*prev)->slack += packet->length;
         } else {
             _size -= packet->length;
             _size -= packet->slack;