On Tue, 2013-11-26 at 18:35 -0800, Josh Triplett wrote:
> On Tue, Nov 26, 2013 at 06:26:36PM -0800, Joe Perches wrote:
> > On Wed, 2013-11-27 at 10:59 +0900, Jingoo Han wrote:
> > []
> > > ./drivers/pci/host/pci-mvebu.c
> > > static void __iomem *mvebu_pcie_map_registers(struct platform_device *pdev,
> > > struct device_node *np, struct mvebu_pcie_port *port)
> > > {
> > > .....
> > >
> > > ret = of_address_to_resource(np, 0, ®s);
> > > if (ret)
> > > - return ERR_PTR(ret);
> > > + return (void __iomem *)ERR_PTR(ret);
> > >
> > > However, other engineers said that "(void __iomem *)ERR_PTR(ret)"
> > > is not a general pattern. I cannot find the proper method to resolve
> > > this sparse warning.
> > >
> > > In this case, how can I resolve this sparse warning?
> >
> > I think there's no problem using the cast. It's not a
> > pattern because it's not been required before as function
> > returns have not previously been declared __iomem.
> >
> > Or, perhaps the arm|hexagon specific #define below could
> > be made generic so it could be used.
> >
> > arch/arm/include/asm/io.h:#define IOMEM(x) ((void __force __iomem *)(x))
> >
> > return IOMEM(ERR_PTR(ret));
> >
> > There aren't any current uses of return IOMEM(foo) either
> > though so the direct cast is probably more appropriate.
>
> I don't think that #define is appropriate for any non-constant value;
> almost any instance of that __force cast applied to a variable would be
> better written by fixing types more appropriately. I'd suggest
> updating that #define for both architectures to use BUILD_BUG_ON to
> assert __builtin_constant_p on its argument.
That's probably a good idea.
There are at least a couple things would likely need to be
fixed up if the #define were changed.
arch/arm/plat-omap/sram.c
drivers/clocksource/bcm_kona_timer.c
I've no issue with either a direct cast or your idea of
a new static inline like ERR_PTR_IO or IOMEM_ERR_PTR or
any other appropriate name.
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