The patch titled
Subject: kernel/resource: allow region_intersects users to hold resource_lock
has been added to the -mm tree. Its filename is
kernel-resource-allow-region_intersects-users-to-hold-resource_lock.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kernel-resource-allow-region_intersects-users-to-hold-resource_lock.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kernel-resource-allow-region_intersects-users-to-hold-resource_lock.patch
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------------------------------------------------------
From: Alistair Popple <apopple@xxxxxxxxxx>
Subject: 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 is used in a future fix to
__request_free_mem_region().
Link: https://lkml.kernel.org/r/20210419070109.4780-1-apopple@xxxxxxxxxx
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Muchun Song <smuchun@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/resource.c | 52 ++++++++++++++++++++++++++------------------
1 file changed, 31 insertions(+), 21 deletions(-)
--- a/kernel/resource.c~kernel-resource-allow-region_intersects-users-to-hold-resource_lock
+++ a/kernel/resource.c
@@ -502,6 +502,34 @@ int __weak page_is_ram(unsigned long pfn
}
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;
+
+ 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);
_
Patches currently in -mm which might be from apopple@xxxxxxxxxx are
kernel-resource-allow-region_intersects-users-to-hold-resource_lock.patch
kernel-resource-refactor-__request_region-to-allow-external-locking.patch
kernel-resource-fix-locking-in-request_free_mem_region.patch
