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    SubjectRe: [PATCH v2 5/7] [PATCH 5/8] can: SJA1000 generic platform bus driver
    On Tue, 12 May 2009 11:28:02 +0200
    Wolfgang Grandegger <wg@grandegger.com> wrote:

    > This driver adds support for the SJA1000 chips connected to the
    > "platform bus", which can be found on various embedded systems.

    [...]

    > +
    > +static u8 sp_read_reg(const struct net_device *dev, int reg)
    > +{
    > + return ioread8((void __iomem *)(dev->base_addr + reg));
    > +}
    > +
    > +static void sp_write_reg(const struct net_device *dev, int reg, u8 val)
    > +{
    > + iowrite8(val, (void __iomem *)(dev->base_addr + reg));
    > +}

    So there's no locking around accesses to the hardware at all. How do you
    protect against concurrent access?

    [...]

    > +static int sp_remove(struct platform_device *pdev)
    > +{
    > + struct net_device *dev = dev_get_drvdata(&pdev->dev);
    > + struct resource *res;
    > +
    > + unregister_sja1000dev(dev);
    > + dev_set_drvdata(&pdev->dev, NULL);
    > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    > + release_mem_region(res->start, res->end - res->start + 1);
    > +
    > + if (dev->base_addr)
    > + iounmap((void __iomem *)dev->base_addr);

    Seems like you should unmap it before releasing it back to the kernel.
    Nobody else is ever going to jump in and try to map it, but still...

    > + free_sja1000dev(dev);
    > +
    > + return 0;
    > +}

    jon


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