RE: [PATCH v4 4/7] x86, mm, pat: Add pgprot_writethrough() for WT

[Elliott, Robert (Server Storage)]

> -----Original Message-----
> From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Kani, Toshimitsu
> Sent: Monday, 27 October, 2014 5:56 PM
> To: hpa@xxxxxxxxx; tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; akpm@linux-
> foundation.org; arnd@xxxxxxxx
> Cc: linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> jgross@xxxxxxxx; stefan.bader@xxxxxxxxxxxxx; luto@xxxxxxxxxxxxxx;
> hmh@xxxxxxxxxx; yigal@xxxxxxxxxxxxx; konrad.wilk@xxxxxxxxxx; Kani,
> Toshimitsu
> Subject: [PATCH v4 4/7] x86, mm, pat: Add pgprot_writethrough() for
> WT
> 
> This patch adds pgprot_writethrough() for setting WT to a given
> pgprot_t.
> 
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
...
> diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> index a214f5a..a0264d3 100644
> --- a/arch/x86/mm/pat.c
> +++ b/arch/x86/mm/pat.c
> @@ -896,6 +896,16 @@ pgprot_t pgprot_writecombine(pgprot_t prot)
>  }
>  EXPORT_SYMBOL_GPL(pgprot_writecombine);
> 
> +pgprot_t pgprot_writethrough(pgprot_t prot)
> +{
> +	if (pat_enabled)
> +		return __pgprot(pgprot_val(prot) |
> +				cachemode2protval(_PAGE_CACHE_MODE_WT));
> +	else
> +		return pgprot_noncached(prot);
> +}
> +EXPORT_SYMBOL_GPL(pgprot_writethrough);
...

Would you be willing to use EXPORT_SYMBOL for the new 
pgprot_writethrough function to provide more flexibility
for modules to utilize the new feature?  In x86/mm, 18 of 60
current exports are GPL and 42 are not GPL.

---
Rob Elliott    HP Server Storage


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