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

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Date:   Tue, 5 Mar 2019 13:49:53 +0800
From:   Wei Yang <richardw.yang@...ux.intel.com>
To:     Like Xu <like.xu@...ux.intel.com>
Cc:     Wei Yang <richardw.yang@...ux.intel.com>,
        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 Tue, Mar 05, 2019 at 01:45:31PM +0800, Like Xu wrote:
>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.
>

Yep, thanks for your suggestion :-)

>> 
>> > ---
>> > 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
>> 

-- 
Wei Yang
Help you, Help me