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 <[email protected]>
> AuthorDate: Fri, 13 Oct 2017 14:56:41 -0700
> Committer: Ingo Molnar <[email protected]>
> 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 <[email protected]>
> Reviewed-by: Thomas Gleixner <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Link: http://lkml.kernel.org/r/[email protected]
> Signed-off-by: Ingo Molnar <[email protected]>
> ---
> 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.
