Re-send [PATCH 2 2.6.7-rc3-bk6] pcnet32: recover after rx hang.

[Don Fry <brazilnut@us.ibm.com>]

This patch fixes a receive hang that occasionally occurs after a Tx
FIFO underrun.  The receive dma remains in a hung state sometimes.  The
transmit operations continue to occur, but no receive activity.

This was reproduced on several ppc64 systems and the fix has been verified
there.  The patch has been tested as well on an ia32 system, which did
not experience the hang because it did not have fifo underruns, which is
a preqrequisite for the hang.  The memory barriers decreased the frequency
of occurrence.  The final change to reset the chip instead of just stopping
it eliminated the last hangs.

Please also apply against 2.4.27 (with offset of -1), tested ia32.

Signed-off-by: Don Fry <brazilnut@us.ibm.com>

--- linux-2.6.7-rc3-bk6/drivers/net/orig.pcnet32.c	Mon Jun 14 12:19:09 2004
+++ linux-2.6.7-rc3-bk6/drivers/net/pcnet32.c	Tue Jun 15 09:36:43 2004
@@ -22,8 +22,8 @@
  *************************************************************************/
 
 #define DRV_NAME	"pcnet32"
-#define DRV_VERSION	"1.30c"
-#define DRV_RELDATE	"05.25.2004"
+#define DRV_VERSION	"1.30d"
+#define DRV_RELDATE	"06.01.2004"
 #define PFX		DRV_NAME ": "
 
 static const char *version =
@@ -245,6 +245,7 @@ static int full_duplex[MAX_UNITS];
  * v1.30b  24 May 2004 Don Fry fix bogus tx carrier errors with 79c973,
  *	   assisted by Bruce Penrod <bmpenrod@endruntechnologies.com>.
  * v1.30c  25 May 2004 Don Fry added netif_wake_queue after pcnet32_restart.
+ * v1.30d  01 Jun 2004 Don Fry discard oversize rx packets.
  */
 
 
@@ -1907,7 +1908,13 @@ pcnet32_rx(struct net_device *dev)
 	    short pkt_len = (le32_to_cpu(lp->rx_ring[entry].msg_length) & 0xfff)-4;
 	    struct sk_buff *skb;
 
-	    if (pkt_len < 60) {
+	    /* Discard oversize frames. */
+	    if (unlikely(pkt_len > PKT_BUF_SZ - 2)) {
+		if (netif_msg_drv(lp))
+		    printk(KERN_ERR "%s: Impossible packet size %d!\n",
+			    dev->name, pkt_len);
+		lp->stats.rx_errors++;
+	    } else if (pkt_len < 60) {
 		if (netif_msg_rx_err(lp))
 		    printk(KERN_ERR "%s: Runt packet!\n", dev->name);
 		lp->stats.rx_errors++;

-- 
Don Fry
brazilnut@us.ibm.com