linux-kernel - Re: [PATCH] mm: fix 'size' alignment in devm_memremap

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Message-ID: <1457486191.15454.532.camel@hpe.com>
Date:	Tue, 08 Mar 2016 18:16:31 -0700
From:	Toshi Kani <toshi.kani@....com>
To:	Dan Williams <dan.j.williams@...el.com>, akpm@...ux-foundation.org
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: fix 'size' alignment in devm_memremap_pages()

On Tue, 2016-03-08 at 14:32 -0800, Dan Williams wrote:
> We need to align the end address, not just the size.
> 
> Cc: Toshi Kani <toshi.kani@....com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>

The change looks good.

Reviewed-by: Toshi Kani <toshi.kani@....com>

Thanks,
-Toshi

> ---
> Hi Andrew, one more fixup to devm_memremap_pages().  I was discussing
> patch "mm: fix mixed zone detection in devm_memremap_pages" with Toshi
> and noticed that it was mishandling the end-of-range alignment.  Please
> apply or fold this into the existing patch.
> 
>  kernel/memremap.c |   12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index c0f11a498a5a..60baf4d3401e 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -270,14 +270,16 @@ struct dev_pagemap
> *find_dev_pagemap(resource_size_t phys)
>  void *devm_memremap_pages(struct device *dev, struct resource *res,
>  		struct percpu_ref *ref, struct vmem_altmap *altmap)
>  {
> -	resource_size_t align_start = res->start & ~(SECTION_SIZE - 1);
> -	resource_size_t align_size = ALIGN(resource_size(res),
> SECTION_SIZE);
> -	int is_ram = region_intersects(align_start, align_size, "System
> RAM");
> -	resource_size_t key, align_end;
> +	resource_size_t key, align_start, align_size, align_end;
>  	struct dev_pagemap *pgmap;
>  	struct page_map *page_map;
> +	int error, nid, is_ram;
>  	unsigned long pfn;
> -	int error, nid;
> +
> +	align_start = res->start & ~(SECTION_SIZE - 1);
> +	align_size = ALIGN(res->start + resource_size(res),
> SECTION_SIZE)
> +		- align_start;
> +	is_ram = region_intersects(align_start, align_size, "System
> RAM");
>  
>  	if (is_ram == REGION_MIXED) {
>  		WARN_ONCE(1, "%s attempted on mixed region %pr\n",
>