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Subject: Re: [PATCH v4 1/2] mm/hmm: make full use of walk_page_range()
To:     Christoph Hellwig <hch@lst.de>
CC:     Jerome Glisse <jglisse@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Shuah Khan <shuah@kernel.org>, <linux-rdma@vger.kernel.org>,
        <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <linux-kselftest@vger.kernel.org>
References: <20191104222141.5173-1-rcampbell@nvidia.com>
 <20191104222141.5173-2-rcampbell@nvidia.com> <20191112151856.GB12550@lst.de>
From:   Ralph Campbell <rcampbell@nvidia.com>
Message-ID: <3e2da09f-a305-14b7-c116-77e4d1b9e3f2@nvidia.com>
Date:   Tue, 12 Nov 2019 14:21:19 -0800
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On 11/12/19 7:18 AM, Christoph Hellwig wrote:
> Looks good,
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> Although we could clean this up a tidbit more by removing the start
> variable:
> 
> diff --git a/mm/hmm.c b/mm/hmm.c
> index d4984a08ed9b..b5b1ed646c2f 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -667,10 +667,9 @@ static const struct mm_walk_ops hmm_walk_ops = {
>    */
>   long hmm_range_fault(struct hmm_range *range, unsigned int flags)
>   {
> -	unsigned long start = range->start;
>   	struct hmm_vma_walk hmm_vma_walk = {
>   		.range = range,
> -		.last = start,
> +		.last = range->start,
>   		.flags = flags,
>   	};
>   	struct mm_struct *mm = range->notifier->mm;
> @@ -682,9 +681,8 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
>   		/* If range is no longer valid force retry. */
>   		if (mmu_range_check_retry(range->notifier, range->notifier_seq))
>   			return -EBUSY;
> -		ret = walk_page_range(mm, start, range->end, &hmm_walk_ops,
> -				      &hmm_vma_walk);
> -		start = hmm_vma_walk.last;
> +		ret = walk_page_range(mm, hmm_vma_walk.last, range->end,
> +				      &hmm_walk_ops, &hmm_vma_walk);
>   	} while (ret == -EBUSY);
>   
>   	if (ret)
> 

Thanks for the review.
I'll add this to patch 1 since I need to send a v5 for patch 2.