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    Subject[PATCH] Minor fixes to generic do_div

    While tracking down a problem recently, I noticed the description of
    do_div() is not quite right. We also don't check that 'n' is 64-bit
    when running on a 64-bit machine (this would have caused warnings to
    appear on more configurations if we had). And finally, the indentation
    of the \ characters in the 64-bit case don't match those in the 32-bit case,
    so change those to match.

    Signed-off-by: Matthew Wilcox <matthew@wil.cx>

    diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
    index 8f4e319..0edfb96 100644
    --- a/include/asm-generic/div64.h
    +++ b/include/asm-generic/div64.h
    @@ -6,10 +6,10 @@ #define _ASM_GENERIC_DIV64_H
    *
    * The semantics of do_div() are:
    *
    - * uint32_t do_div(uint64_t *n, uint32_t base)
    + * uint32_t do_div(uint64_t n, uint32_t base)
    * {
    - * uint32_t remainder = *n % base;
    - * *n = *n / base;
    + * uint32_t remainder = n % base;
    + * n = n / base;
    * return remainder;
    * }
    *
    @@ -22,12 +22,16 @@ #include <linux/compiler.h>

    #if BITS_PER_LONG == 64

    -# define do_div(n,base) ({ \
    - uint32_t __base = (base); \
    - uint32_t __rem; \
    - __rem = ((uint64_t)(n)) % __base; \
    - (n) = ((uint64_t)(n)) / __base; \
    - __rem; \
    +/* The unnecessary pointer compare is there
    + * to check for type safety (n must be 64bit)
    + */
    +# define do_div(n,base) ({ \
    + uint32_t __base = (base); \
    + uint32_t __rem; \
    + (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
    + __rem = ((uint64_t)(n)) % __base; \
    + (n) = ((uint64_t)(n)) / __base; \
    + __rem; \
    })

    #elif BITS_PER_LONG == 32
    -
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      Last update: 2006-10-20 05:37    [W:0.023 / U:60.176 seconds]
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