Igbe: Newer kernels seem to allow TSO headers and packet data to be in one desc

Implement some code we used to panic on as it actually does happen with the
e1000 driver in Linux 3.3+. We used to assume that a TSO header would never
be part of a larger payload, however it appears as though it now can be.

diff --git a/src/dev/i8254xGBe.cc b/src/dev/i8254xGBe.cc
index 71b88377d93dc5249dae707ec07293a5b365f74b..d2b7c0f7576a927d705590ee1ec19db19c576b28 100644 (file)
--- a/src/dev/i8254xGBe.cc
+++ b/src/dev/i8254xGBe.cc
@@ -1650,11 +1650,9 @@ IGbE::TxDescCache::headerComplete()
         unusedCache.pop_front();
         usedCache.push_back(desc);
     } else {
-        // I don't think this case happens, I think the headrer is always
-        // it's own packet, if it wasn't it might be as simple as just
-        // incrementing descBytesUsed by the header length, but I'm not
-        // completely sure
-        panic("TSO header part of bigger packet, not implemented\n");
+        DPRINTF(EthernetDesc, "TSO: header part of larger payload\n");
+        tsoDescBytesUsed = tsoHeaderLen;
+        tsoLoadedHeader = true;
     }
     enableSm();
     igbe->checkDrain();