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    SubjectRe: [PATCH v2 4/5] Input: gpio-keys - Switch to bitmap_zalloc()
    On Sat, Jun 16, 2018 at 1:08 AM Yury Norov <ynorov@caviumnetworks.com> wrote:
    >
    > On Fri, Jun 15, 2018 at 04:20:16PM +0300, Andy Shevchenko wrote:
    > > External Email
    > >
    > > Switch to bitmap_zalloc() to show clearly what we are allocating.
    > > Besides that it returns pointer of bitmap type instead of opaque void *.
    >
    > Nit. There's no special type for bitmaps, bitmap_zalloc() returns long *.
    > Is it less opaque than void *, not sure.

    Yes, it enables type checking by compiler, which is good thing.
    You can't supply other pointer to this API, like

    unsigned char *bar = kmalloc(BITS_PER_LONGS(nbits) * sizeof(unsigned
    long), GFP_KERNEL);
    ...

    bitmap_free(bar); //<< compiler will not pass this silently!

    Or other way around:

    unsigned char *foo = bitmap_alloc(nbits, GFP_KERNEL); //<< wrong types!

    --
    With Best Regards,
    Andy Shevchenko

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