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

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Date:   Tue, 12 Feb 2019 08:13:08 +0800
From:   Wei Yang <richardw.yang@...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 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?

>---
> 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