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    SubjectRe: [PATCH] mtd: dc21285.c: remove double check of CONFIG_ARCH_NETWINDER
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    On Tue, 2012-05-29 at 12:06 +0200, Christian Dietrich wrote:
    > When CONFIG_ARCH_NETWINDER is unset nw_en_write is a NOP. But
    > machine_is_netwinder() also checks for
    > CONFIG_ARCH_NETWINDER. Therefore in the !netwinder case the
    > preprocessed code is:
    >
    > if (0)
    > do {} while(0);

    It's not a double check. It's a compile time check for "do we even need
    to build this code at all?", and a separate run time check for "do we
    need to run this code now?".

    Think about the case where CONFIG_ARCH_NETWINDER is set, but you aren't
    actually running this kernel binary on a netwinder *today*.

    Yes, we might not support multi-platform kernels on ARM yet, but we are
    slowly getting there. This kind of change just makes that harder.

    And even if the machine_is_netwinder() "function" is *currently* a macro
    which is hard-coded to return one or zero, that just means that your
    change achieves nothing in the compiler output. It'll be silently
    optimised away, or not, as appropriate.

    --
    dwmw2
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