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kernel/resource: allow region_intersects users to hold resource_lock

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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: Alistair 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alistair Popple 2021-05-06 18:05:24 -07:00 committed by Linus Torvalds
parent 97523a4edb
commit d486ccb252
1 changed files with 31 additions and 21 deletions
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52
kernel/resource.c
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@ -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);