[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>

diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index 765ef9541013538869d072dff071fa7e9389dfbb..2a94719a4226a7f4d3d36d25a9838195de515d93 100644 (file)
--- a/drivers/net/8139too.c
+++ b/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;
 }