[PATCH] staging: fieldbus: anybuss: force address space conversion

Sven Van Asbroeck thesven73 at gmail.com
Tue May 21 15:53:15 UTC 2019


On Tue, May 21, 2019 at 11:42 AM Greg KH <gregkh at linuxfoundation.org> wrote:
>
> Ick, if you are using __force, almost always something is wrong.
>

What if I create a separate structure for the regmap context ?

struct anybus_regmap_context {
        void __iomem *base;
};

Then just store the base pointer inside the struct, and pass the struct
as the regmap context:

ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
ctx->base = base;
devm_regmap_init(..., ctx);

static int write_reg_bus(void *context, unsigned int reg,
                  unsigned int val)
{
        struct anybus_regmap_context *ctx = context;
        <now access ctx->base>
}

Penalty is an additional dynamic pointer-size
allocation. Pro: it'll be formally correct ?


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