svn commit: r280163 - head/sys/dev/sfxge

[Andrew Rybchenko]

Author: arybchik
Date: Tue Mar 17 08:23:15 2015
New Revision: 280163
URL: https://svnweb.freebsd.org/changeset/base/280163

Log:
  sfxge: prefetch txq->common if TxQ is started only
  
  Transmit may be called when TxQ is not started yet (i.e. txq->common is
  invalid). TxQ state is checked below when mbuf is processed and dropped
  if TxQ is not started.
  
  Sponsored by:   Solarflare Communications, Inc.
  Approved by:    gnn (mentor)

Modified:
  head/sys/dev/sfxge/sfxge_tx.c

Modified: head/sys/dev/sfxge/sfxge_tx.c
==============================================================================
--- head/sys/dev/sfxge/sfxge_tx.c	Tue Mar 17 08:21:31 2015	(r280162)
+++ head/sys/dev/sfxge/sfxge_tx.c	Tue Mar 17 08:23:15 2015	(r280163)
@@ -423,8 +423,10 @@ sfxge_tx_qdpl_drain(struct sfxge_txq *tx
 	stdp = &txq->dpl;
 	pushed = txq->added;
 
-	prefetch_read_many(sc->enp);
-	prefetch_read_many(txq->common);
+	if (__predict_true(txq->init_state == SFXGE_TXQ_STARTED)) {
+		prefetch_read_many(sc->enp);
+		prefetch_read_many(txq->common);
+	}
 
 	mbuf = stdp->std_get;
 	count = stdp->std_get_count;