can: peak_pci: Fix the way channels are linked together

commit 29830406415c227a54af429d7b300aabd4754237 upstream.

Change the way channels objects are linked together by peak_pci_probe()
avoiding any kernel oops when driver is removed. Side effect is that
the list is now browsed from last to first channel.

Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/net/can/sja1000/peak_pci.c b/drivers/net/can/sja1000/peak_pci.c
index 2c7f503..2147959 100644 (file)
--- a/drivers/net/can/sja1000/peak_pci.c
+++ b/drivers/net/can/sja1000/peak_pci.c
@@ -39,9 +39,9 @@ MODULE_LICENSE("GPL v2");
 #define DRV_NAME  "peak_pci"
 
 struct peak_pci_chan {
-       void __iomem *cfg_base;      /* Common for all channels */
-       struct net_device *next_dev; /* Chain of network devices */
-       u16 icr_mask;                /* Interrupt mask for fast ack */
+       void __iomem *cfg_base;         /* Common for all channels */
+       struct net_device *prev_dev;    /* Chain of network devices */
+       u16 icr_mask;                   /* Interrupt mask for fast ack */
 };
 
 #define PEAK_PCI_CAN_CLOCK     (16000000 / 2)
@@ -98,7 +98,7 @@ static int __devinit peak_pci_probe(struct pci_dev *pdev,
 {
        struct sja1000_priv *priv;
        struct peak_pci_chan *chan;
-       struct net_device *dev, *dev0 = NULL;
+       struct net_device *dev;
        void __iomem *cfg_base, *reg_base;
        u16 sub_sys_id, icr;
        int i, err, channels;
@@ -196,18 +196,14 @@ static int __devinit peak_pci_probe(struct pci_dev *pdev,
                }
 
                /* Create chain of SJA1000 devices */
-               if (i == 0)
-                       dev0 = dev;
-               else
-                       chan->next_dev = dev;
+               chan->prev_dev = pci_get_drvdata(pdev);
+               pci_set_drvdata(pdev, dev);
 
                dev_info(&pdev->dev,
                         "%s at reg_base=0x%p cfg_base=0x%p irq=%d\n",
                         dev->name, priv->reg_base, chan->cfg_base, dev->irq);
        }
 
-       pci_set_drvdata(pdev, dev0);
-
        /* Enable interrupts */
        writew(icr, cfg_base + PITA_ICR + 2);
 
@@ -217,12 +213,11 @@ failure_remove_channels:
        /* Disable interrupts */
        writew(0x0, cfg_base + PITA_ICR + 2);
 
-       for (dev = dev0; dev; dev = chan->next_dev) {
+       for (dev = pci_get_drvdata(pdev); dev; dev = chan->prev_dev) {
                unregister_sja1000dev(dev);
                free_sja1000dev(dev);
                priv = netdev_priv(dev);
                chan = priv->priv;
-               dev = chan->next_dev;
        }
 
        pci_iounmap(pdev, reg_base);
@@ -241,7 +236,7 @@ failure_disable_pci:
 
 static void __devexit peak_pci_remove(struct pci_dev *pdev)
 {
-       struct net_device *dev = pci_get_drvdata(pdev); /* First device */
+       struct net_device *dev = pci_get_drvdata(pdev); /* Last device */
        struct sja1000_priv *priv = netdev_priv(dev);
        struct peak_pci_chan *chan = priv->priv;
        void __iomem *cfg_base = chan->cfg_base;
@@ -255,7 +250,7 @@ static void __devexit peak_pci_remove(struct pci_dev *pdev)
                dev_info(&pdev->dev, "removing device %s\n", dev->name);
                unregister_sja1000dev(dev);
                free_sja1000dev(dev);
-               dev = chan->next_dev;
+               dev = chan->prev_dev;
                if (!dev)
                        break;
                priv = netdev_priv(dev);