Re: [Qemu-devel] [PATCH v3 1/5] bitops: introduce change_bit_atomic

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* guangrong.xiao@gmail.com (guangrong.xiao@gmail.com) wrote:
> From: Xiao Guangrong <xiaoguangrong@tencent.com>
> 
> It will be used by threaded workqueue
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  include/qemu/bitops.h | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
> index 3f0926cf40..c522958852 100644
> --- a/include/qemu/bitops.h
> +++ b/include/qemu/bitops.h
> @@ -79,6 +79,19 @@ static inline void change_bit(long nr, unsigned long *addr)
>      *p ^= mask;
>  }
>  
> +/**
> + * change_bit_atomic - Toggle a bit in memory atomically
> + * @nr: Bit to change
> + * @addr: Address to start counting from
> + */
> +static inline void change_bit_atomic(long nr, unsigned long *addr)
> +{
> +    unsigned long mask = BIT_MASK(nr);
> +    unsigned long *p = addr + BIT_WORD(nr);
> +
> +    atomic_xor(p, mask);
> +}
> +
>  /**
>   * test_and_set_bit - Set a bit and return its old value
>   * @nr: Bit to set
> -- 
> 2.14.5
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK