[PATCH] ixgb: fix ixgb_intr looping checks

This patch undoes a change that we believe will impact performance
adversely, by creating possibly too long a delay between servicing
completions.  The comment pretty much explains it.  We need to call both
cleanup routines each pass through the loop, this time we have a comment
explaining why.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/ixgb/ixgb_main.c

@@ -1613,13 +1613,14 @@ static irqreturn_t ixgb_intr(int irq, void *data, struct pt_regs *regs)
 		__netif_rx_schedule(netdev);
 	}
 #else
-	for (i = 0; i < IXGB_MAX_INTR; i++)
-		if (ixgb_clean_rx_irq(adapter) == FALSE)
+	/* yes, that is actually a & and it is meant to make sure that
+	 * every pass through this for loop checks both receive and
+	 * transmit queues for completed descriptors, intended to
+	 * avoid starvation issues and assist tx/rx fairness. */
+	for(i = 0; i < IXGB_MAX_INTR; i++)
+		if(!ixgb_clean_rx_irq(adapter) &
+		   !ixgb_clean_tx_irq(adapter))
 			break;
-	for (i = 0; i < IXGB_MAX_INTR; i++)
-		if (ixgb_clean_tx_irq(adapter) == FALSE)
-			break;
-
 	/* if RAIDC:EN == 1 and ICR:RXDMT0 == 1, we need to
 	 * set IMS:RXDMT0 to 1 to restart the RBD timer (POLL)
 	 */