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 for <linuxppc-dev@lists.ozlabs.org> from <aneeshkumar.opensource@gmail.com>;
 Mon, 30 Oct 2017 10:03:53 -0600
Subject: Re: [rfc] powerpc/npu: Cleanup MMIO ATSD flushing
To: Balbir Singh <bsingharora@gmail.com>, alistair@popple.id.au,
 mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org, arbab@linux.vnet.ibm.com
References: <20171030123820.29392-1-bsingharora@gmail.com>
From: "Aneesh Kumar K.V" <aneeshkumar.opensource@gmail.com>
Date: Mon, 30 Oct 2017 21:33:46 +0530
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On 10/30/2017 06:08 PM, Balbir Singh wrote:
> +
> +static void pnv_npu2_invalidate_helper(struct npu_context *npu_context,
> +		struct mm_struct *mm, unsigned long start,
> +		unsigned long end, bool flush)
> +{
> +	unsigned long address;
> +	bool is_thp;
> +	unsigned int hshift, shift;
> +
> +	address = start;
> +	do {
> +		local_irq_disable();
> +		find_linux_pte(mm->pgd, address, &is_thp, &hshift);
> +		if (!is_thp)
> +			shift = PAGE_SHIFT;
> +		else
> +			shift = hshift;

Is that correct? if is_thp is 0 can we derive shift from hshift? IIUC we 
set hshift only
if it is a hugepage.

> +		mmio_invalidate(npu_context, address > 0, address, flush,
> +				shift);
> +		local_irq_enable();
> +		address += (1ull << shift);
> +	} while (address < end);
>   }
>   
>

-aneesh