Re: [PATCH] kernel, resource: use resource_overlaps() to simplify region_intersects()

From: Yuan Yao
Date: Mon Feb 18 2019 - 22:24:25 EST


Looks good to me.

Reviewed-by: Yuan Yao <yuan.yao@xxxxxxxxxxxxxxx>


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@xxxxxxxxxxxxxxx>
> ---
> 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