linux-kernel - Re: [PATCH] kernel, resource: use resource_overlaps() to simplify region

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Message-ID: <20190219032133.GA14023@yy-desk-7060>
Date:   Tue, 19 Feb 2019 11:21:33 +0800
From:   Yuan Yao <yuan.yao@...ux.intel.com>
To:     Wei Yang <richardw.yang@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, jack@...e.cz,
        dan.j.williams@...el.com
Subject: Re: [PATCH] kernel, resource: use resource_overlaps() to simplify
 region_intersects()

Looks good to me.

Reviewed-by: Yuan Yao <yuan.yao@...ux.intel.com>


On Mon, Jan 21, 2019 at 09:20:28AM +0800, Wei Yang wrote:
> The three checks in region_intersects() is to see whether two resources
> overlap. This means it could be simplified with one resource_overlaps().
> 
> Also fix two typo in related function.
> 
> Signed-off-by: Wei Yang <richardw.yang@...ux.intel.com>
> ---
>  kernel/iomem.c    |  4 ++--
>  kernel/resource.c | 11 +++++------
>  2 files changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/iomem.c b/kernel/iomem.c
> index f7525e14ebc6..93c264444510 100644
> --- a/kernel/iomem.c
> +++ b/kernel/iomem.c
> @@ -55,7 +55,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size,
>   *
>   * MEMREMAP_WB - matches the default mapping for System RAM on
>   * the architecture.  This is usually a read-allocate write-back cache.
> - * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
> + * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM
>   * memremap() will bypass establishing a new mapping and instead return
>   * a pointer into the direct map.
>   *
> @@ -86,7 +86,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
>  	/* Try all mapping types requested until one returns non-NULL */
>  	if (flags & MEMREMAP_WB) {
>  		/*
> -		 * MEMREMAP_WB is special in that it can be satisifed
> +		 * MEMREMAP_WB is special in that it can be satisfied
>  		 * from the direct map.  Some archs depend on the
>  		 * capability of memremap() to autodetect cases where
>  		 * the requested range is potentially in System RAM.
> diff --git a/kernel/resource.c b/kernel/resource.c
> index b0fbf685c77a..34dfb94305bb 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -521,21 +521,20 @@ EXPORT_SYMBOL_GPL(page_is_ram);
>  int region_intersects(resource_size_t start, size_t size, unsigned long flags,
>  		      unsigned long desc)
>  {
> -	resource_size_t end = start + size - 1;
> +	struct resource res;
>  	int type = 0; int other = 0;
>  	struct resource *p;
>  
> +	res.start = start;
> +	res.end = start + size - 1;
> +
>  	read_lock(&resource_lock);
>  	for (p = iomem_resource.child; p ; p = p->sibling) {
>  		bool is_type = (((p->flags & flags) == flags) &&
>  				((desc == IORES_DESC_NONE) ||
>  				 (desc == p->desc)));
>  
> -		if (start >= p->start && start <= p->end)
> -			is_type ? type++ : other++;
> -		if (end >= p->start && end <= p->end)
> -			is_type ? type++ : other++;
> -		if (p->start >= start && p->end <= end)
> +		if (resource_overlaps(p, &res))
>  			is_type ? type++ : other++;
>  	}
>  	read_unlock(&resource_lock);
> -- 
> 2.19.1