linux-kernel - Re: [PATCH 07/10] x86, xen, mm: Do not need to check if page table is ioremap

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Date:	Tue, 9 Oct 2012 12:13:09 -0400
From:	Konrad Rzeszutek Wilk <konrad@...nel.org>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>, Jacob Shin <jacob.shin@....com>,
	Tejun Heo <tj@...nel.org>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	linux-kernel@...r.kernel.org,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Jeremy Fitzhardinge <jeremy@...p.org>
Subject: Re: [PATCH 07/10] x86, xen, mm: Do not need to check if page table
 is ioremap

On Mon, Oct 08, 2012 at 09:39:15PM -0700, Yinghai Lu wrote:
> All page table buf are pre-mapped, and could use _va to access them.

"__va", not "_va". And can you also include the name of the patch
that makes them pre-mapped?

> 
> Remove the not needed checking.

<sigh>
"Remove the ioremap check."

> 
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Cc: Jeremy Fitzhardinge <jeremy@...p.org>
> ---
>  arch/x86/xen/mmu.c |    8 ++------
>  1 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 7a769b7..9c0956c 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -1412,13 +1412,9 @@ static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
>  
>  	/*
>  	 * If the new pfn is within the range of the newly allocated
> -	 * kernel pagetable, and it isn't being mapped into an
> -	 * early_ioremap fixmap slot as a freshly allocated page, make sure
> -	 * it is RO.
> +	 * kernel pagetable, make sure it is RO.
>  	 */
> -	if (((!is_early_ioremap_ptep(ptep) &&
> -			pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
> -			(is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
> +	if (pfn >= pgt_buf_start && pfn < pgt_buf_top)
>  		pte = pte_wrprotect(pte);
>  
>  	return pte;
> -- 
> 1.7.7
> 
> --
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