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

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Message-ID: <8d01ff6c-94bb-8b94-5f51-5d229b3e24e5@linux.intel.com>
Date:   Tue, 5 Mar 2019 13:45:31 +0800
From:   Like Xu <like.xu@...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()

On 2019/2/12 8:13, Wei Yang wrote:
> 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>
> 
> Hello~
> 
> Would someone like to take a look?

No semantic change and it looks good to me.

Reviewed-by: Like Xu <like.xu@...ux.intel.com>

You may use scripts/get_maintainer.pl to cc more maintainers.

> 
>> ---
>> 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
>