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Re: [PATCH] x86: squash lines for simple wrapper functions

From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH] x86: squash lines for simple wrapper functions
Date 2016-09-08 08:40 +0200
Message-ID <sf1a9-2fT-7@gated-at.bofh.it> (permalink)
References <semJH-1kY-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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* Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> Remove unneeded variables and assignments.  I am also removing
> unnecessary parentheses while I am here.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
> 
>  arch/x86/kernel/apic/apic_flat_64.c  | 16 +++-------------
>  arch/x86/kernel/apic/apic_numachip.c |  5 +----
>  arch/x86/kernel/apic/x2apic_uv_x.c   |  5 +----
>  arch/x86/mm/pat_rbtree.c             |  4 +---
>  arch/x86/platform/uv/bios_uv.c       |  7 ++-----
>  arch/x86/platform/uv/tlb_uv.c        |  6 +-----
>  6 files changed, 9 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
> index 5b2ae10..c7228f9 100644
> --- a/arch/x86/kernel/apic/apic_flat_64.c
> +++ b/arch/x86/kernel/apic/apic_flat_64.c
> @@ -116,27 +116,17 @@ static void flat_send_IPI_all(int vector)
>  
>  static unsigned int flat_get_apic_id(unsigned long x)
>  {
> -	unsigned int id;
> -
> -	id = (((x)>>24) & 0xFFu);
> -
> -	return id;
> +	return ((x) >> 24) & 0xFFu;

So while we are removing unnecessary things, exactly why does the 'x' need 
parentheses?

>  static unsigned long set_apic_id(unsigned int id)
>  {
> -	unsigned long x;
> -
> -	x = ((id & 0xFFu)<<24);
> -	return x;
> +	return (id & 0xFFu) << 24;

'id' is already unsigned, why does the 'u' have to be stressed in the literal? 
(Ditto for other places as well)

>  static unsigned long numachip1_set_apic_id(unsigned int id)
>  {
> -	unsigned long x;
> -
> -	x = ((id & 0xffU) << 24);
> -	return x;
> +	return (id & 0xffU) << 24;
>  }

Why is the spelling of the literal inconsistent here with the other patterns?

> +++ b/arch/x86/kernel/apic/x2apic_uv_x.c
> @@ -533,11 +533,8 @@ static unsigned int x2apic_get_apic_id(unsigned long x)
>  
>  static unsigned long set_apic_id(unsigned int id)
>  {
> -	unsigned long x;
> -
>  	/* maskout x2apic_extra_bits ? */
> -	x = id;
> -	return x;
> +	return id;
>  }

This was clearly left there to document a quirk and as a placeholder for future 
changes.

Thanks,

	Ingo

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[PATCH] x86: squash lines for simple wrapper functions Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-09-06 13:30 +0200
  Re: [PATCH] x86: squash lines for simple wrapper functions Ingo Molnar <mingo@kernel.org> - 2016-09-08 08:40 +0200

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