[PATCH 1/2] Fix race between device reset and start_xmit
authorFelix Fietkau <nbd@openwrt.org>
Fri, 7 Dec 2007 00:03:06 +0000 (00:03 +0000)
committerFelix Fietkau <nbd@openwrt.org>
Fri, 7 Dec 2007 00:03:06 +0000 (00:03 +0000)
Signed-off-by: oliver@opencloud.com
SVN-Revision: 9664

target/linux/ar7/files/drivers/net/cpmac.c

index 2c8d529..45bd1ee 100644 (file)
@@ -37,6 +37,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <asm/gpio.h>
+#include <asm/atomic.h>
 
 MODULE_AUTHOR("Eugene Konev <ejka@imfi.kspu.ru>");
 MODULE_DESCRIPTION("TI AR7 ethernet driver (CPMAC)");
@@ -211,6 +212,7 @@ struct cpmac_priv {
        struct net_device *dev;
        struct work_struct reset_work;
        struct platform_device *pdev;
+       atomic_t reset_pending;
 };
 
 static irqreturn_t cpmac_irq(int, void *);
@@ -460,6 +462,9 @@ static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
        struct cpmac_desc *desc;
        struct cpmac_priv *priv = netdev_priv(dev);
 
+       if (unlikely(atomic_read(&priv->reset_pending)))
+               return NETDEV_TX_BUSY;
+
        if (unlikely(skb_padto(skb, ETH_ZLEN)))
                return NETDEV_TX_OK;
 
@@ -639,14 +644,14 @@ static void cpmac_clear_tx(struct net_device *dev)
                priv->desc_ring[i].dataflags = 0;
                if (priv->desc_ring[i].skb) {
                        dev_kfree_skb_any(priv->desc_ring[i].skb);
-                       if (netif_subqueue_stopped(dev, i))
-                           netif_wake_subqueue(dev, i);
+                       priv->desc_ring[i].skb = NULL;
                }
        }
 }
 
 static void cpmac_hw_error(struct work_struct *work)
 {
+       int i;
        struct cpmac_priv *priv =
                container_of(work, struct cpmac_priv, reset_work);
 
@@ -655,7 +660,45 @@ static void cpmac_hw_error(struct work_struct *work)
        spin_unlock(&priv->rx_lock);
        cpmac_clear_tx(priv->dev);
        cpmac_hw_start(priv->dev);
-       netif_start_queue(priv->dev);
+       barrier();
+       atomic_dec(&priv->reset_pending);
+       
+       for (i = 0; i < CPMAC_QUEUES; i++) {
+               netif_wake_subqueue(priv->dev, i);
+       }
+       netif_wake_queue(priv->dev);
+}
+
+static void cpmac_check_status(struct net_device *dev)
+{
+       struct cpmac_priv *priv = netdev_priv(dev);
+
+       u32 macstatus = cpmac_read(priv->regs, CPMAC_MAC_STATUS);
+       int rx_channel = (macstatus >> 8) & 7;
+       int rx_code = (macstatus >> 12) & 15;
+       int tx_channel = (macstatus >> 16) & 7;
+       int tx_code = (macstatus >> 20) & 15;
+
+       if (rx_code || tx_code) {
+               if (netif_msg_drv(priv) && net_ratelimit()) {
+                       /* Can't find any documentation on what these error codes actually are.
+                        * So just log them and hope..
+                        */
+                       if (rx_code)
+                               printk(KERN_WARNING "%s: host error %d on rx channel %d (macstatus %08x), resetting\n",
+                                      dev->name, rx_code, rx_channel, macstatus);
+                       if (tx_code)
+                               printk(KERN_WARNING "%s: host error %d on tx channel %d (macstatus %08x), resetting\n",
+                                      dev->name, tx_code, tx_channel, macstatus);
+               }
+               
+               netif_stop_queue(dev);
+               cpmac_hw_stop(dev);
+               if (schedule_work(&priv->reset_work))
+                       atomic_inc(&priv->reset_pending);                       
+               if (unlikely(netif_msg_hw(priv)))
+                       cpmac_dump_regs(dev);
+       }
 }
 
 static irqreturn_t cpmac_irq(int irq, void *dev_id)
@@ -687,48 +730,33 @@ static irqreturn_t cpmac_irq(int irq, void *dev_id)
 
        cpmac_write(priv->regs, CPMAC_MAC_EOI_VECTOR, 0);
 
-       if (unlikely(status & (MAC_INT_HOST | MAC_INT_STATUS))) {
-               if (netif_msg_drv(priv) && net_ratelimit())
-                       printk(KERN_ERR "%s: hw error, resetting...\n",
-                              dev->name);
-               netif_stop_queue(dev);
-               cpmac_hw_stop(dev);
-               schedule_work(&priv->reset_work);
-               if (unlikely(netif_msg_hw(priv)))
-                       cpmac_dump_regs(dev);
-       }
+       if (unlikely(status & (MAC_INT_HOST | MAC_INT_STATUS)))
+               cpmac_check_status(dev);
 
        return IRQ_HANDLED;
 }
 
 static void cpmac_tx_timeout(struct net_device *dev)
 {
-       struct cpmac_priv *priv = netdev_priv(dev);
        int i;
+       struct cpmac_priv *priv = netdev_priv(dev);
 
        spin_lock(&priv->lock);
        dev->stats.tx_errors++;
        spin_unlock(&priv->lock);
        if (netif_msg_tx_err(priv) && net_ratelimit())
                printk(KERN_WARNING "%s: transmit timeout\n", dev->name);
-       /* 
-        * FIXME: waking up random queue is not the best thing to
-        * do... on the other hand why we got here at all?
-        */
-#ifdef CONFIG_NETDEVICES_MULTIQUEUE
-       for (i = 0; i < CPMAC_QUEUES; i++)
-               if (priv->desc_ring[i].skb) {
-                       priv->desc_ring[i].dataflags = 0;
-                       dev_kfree_skb_any(priv->desc_ring[i].skb);
-                       netif_wake_subqueue(dev, i);
-                       break;
-               }
-#else
-       priv->desc_ring[0].dataflags = 0;
-       if (priv->desc_ring[0].skb)
-               dev_kfree_skb_any(priv->desc_ring[0].skb);
-       netif_wake_queue(dev);
-#endif
+
+       atomic_inc(&priv->reset_pending);
+       barrier();
+       cpmac_clear_tx(dev);
+       barrier();
+       atomic_dec(&priv->reset_pending);
+
+       netif_wake_queue(priv->dev);
+       for (i = 0; i < CPMAC_QUEUES; i++) {
+               netif_wake_subqueue(dev, i);
+       }
 }
 
 static int cpmac_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
@@ -924,6 +952,7 @@ static int cpmac_open(struct net_device *dev)
                goto fail_irq;
        }
 
+       atomic_set(&priv->reset_pending, 0);
        INIT_WORK(&priv->reset_work, cpmac_hw_error);
        cpmac_hw_start(dev);