[PATCH] 8139too: be sure to progress during rtl8139_rx()

From: Francois Romieu <romieu@fr.zoreil.com>

If the Rx buffer gets corrupted or the FIFO hangs in new interesting ways,
this code prevents the driver from looping in ksoftirqd context without
making any progress.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

drivers/net/8139too.c

@@ -593,6 +593,7 @@ struct rtl8139_private {
 	int time_to_die;
 	struct mii_if_info mii;
 	unsigned int regs_len;
+	unsigned long fifo_copy_timeout;
 };
 
 MODULE_AUTHOR ("Jeff Garzik <jgarzik@pobox.com>");
@@ -1955,7 +1956,7 @@ static int rtl8139_rx(struct net_device *dev, struct rtl8139_private *tp,
 	unsigned int rx_size = 0;
 
 	DPRINTK ("%s: In rtl8139_rx(), current %4.4x BufAddr %4.4x,"
-		 " free to %4.4x, Cmd %2.2x.\n", dev->name, cur_rx,
+		 " free to %4.4x, Cmd %2.2x.\n", dev->name, (u16)cur_rx,
 		 RTL_R16 (RxBufAddr),
 		 RTL_R16 (RxBufPtr), RTL_R8 (ChipCmd));
 
@@ -1993,10 +1994,24 @@ static int rtl8139_rx(struct net_device *dev, struct rtl8139_private *tp,
 		 * since EarlyRx is disabled.
 		 */
 		if (unlikely(rx_size == 0xfff0)) {
+			if (!tp->fifo_copy_timeout)
+				tp->fifo_copy_timeout = jiffies + 2;
+			else if (time_after(jiffies, tp->fifo_copy_timeout)) {
+				DPRINTK ("%s: hung FIFO. Reset.", dev->name);
+				rx_size = 0;
+				goto no_early_rx;
+			}
+			if (netif_msg_intr(tp)) {
+				printk(KERN_DEBUG "%s: fifo copy in progress.",
+				       dev->name);
+			}
 			tp->xstats.early_rx++;
 			break;
 		}
 
+no_early_rx:
+		tp->fifo_copy_timeout = 0;
+
 		/* If Rx err or invalid rx_size/rx_status received
 		 * (which happens if we get lost in the ring),
 		 * Rx process gets reset, so we abort any further
@@ -2057,6 +2072,14 @@ static int rtl8139_rx(struct net_device *dev, struct rtl8139_private *tp,
 #endif
 
 	tp->cur_rx = cur_rx;
+
+	/*
+	 * The receive buffer should be mostly empty.
+	 * Tell NAPI to reenable the Rx irq.
+	 */
+	if (tp->fifo_copy_timeout)
+		received = budget;
+
 out:
 	return received;
 }