Commit d486ccb2 authored by Alistair Popple's avatar Alistair Popple Committed by Linus Torvalds
Browse files

kernel/resource: allow region_intersects users to hold resource_lock 

Introduce a version of region_intersects() that can be called with the
resource_lock already held.

This will be used in a future fix to __request_free_mem_region().

[akpm@linux-foundation.org: make __region_intersects static]

Link: https://lkml.kernel.org/r/20210419070109.4780-1-apopple@nvidia.com


Signed-off-by: default avatarAlistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 97523a4e

kernel/resource.c

+31 −21
Original line number Diff line number Diff line
@@ -502,6 +502,34 @@ int __weak page_is_ram(unsigned long pfn) 
}

EXPORT_SYMBOL_GPL(page_is_ram);



static int __region_intersects(resource_size_t start, size_t size,

			unsigned long flags, unsigned long desc)

{

	struct resource res;

	int type = 0; int other = 0;

	struct resource *p;



	res.start = start;

	res.end = start + size - 1;



	for (p = iomem_resource.child; p ; p = p->sibling) {

		bool is_type = (((p->flags & flags) == flags) &&

				((desc == IORES_DESC_NONE) ||

				 (desc == p->desc)));



		if (resource_overlaps(p, &res))

			is_type ? type++ : other++;

	}



	if (type == 0)

		return REGION_DISJOINT;



	if (other == 0)

		return REGION_INTERSECTS;



	return REGION_MIXED;

}



/**

 * region_intersects() - determine intersection of region with known resources

 * @start: region start address
@@ -525,31 +553,13 @@ EXPORT_SYMBOL_GPL(page_is_ram); 
int region_intersects(resource_size_t start, size_t size, unsigned long flags,

		      unsigned long desc)

{

	struct resource res;

	int type = 0; int other = 0;

	struct resource *p;



	res.start = start;

	res.end = start + size - 1;

	int ret;



	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 (resource_overlaps(p, &res))

			is_type ? type++ : other++;

	}

	ret = __region_intersects(start, size, flags, desc);

	read_unlock(&resource_lock);



	if (type == 0)

		return REGION_DISJOINT;



	if (other == 0)

		return REGION_INTERSECTS;



	return REGION_MIXED;

	return ret;

}

EXPORT_SYMBOL_GPL(region_intersects);