On Tue, Oct 17, 2017 at 09:21:46AM -0700, tip-bot for Andi Kleen wrote:
> Commit-ID: cbe96375025e14fc76f9ed42ee5225120d7210f8
> Gitweb: https://git.kernel.org/tip/cbe96375025e14fc76f9ed42ee5225120d7210f8
> Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> AuthorDate: Fri, 13 Oct 2017 14:56:41 -0700
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Tue, 17 Oct 2017 17:14:56 +0200
>
> bitops: Add clear/set_bit32() to linux/bitops.h
>
> Add two simple wrappers around set_bit/clear_bit() that accept
> the common case of an u32 array. This avoids writing
> casts in all callers.
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/20171013215645.23166-2-andi@xxxxxxxxxxxxxx
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
> include/linux/bitops.h | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
...
> + * set_bit32 - Set a bit in memory for u32 array
> + * @nr: Bit to clear
> + * @addr: u32 * address of bitmap
> + *
> + * Same as set_bit, but avoids needing casts for u32 arrays.
> + */
> +
> +static __always_inline void set_bit32(long nr, volatile u32 *addr)
> +{
> + set_bit(nr, (volatile unsigned long *)addr);
> +}
This does not work at all on 64 bit big endian machines. If e.g. the array
would contain only one 32 bit member set_bit() would write to whatever is
behind the array.
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