[PATCH v5 1/3] kernel/resource: Allow region_intersects users to hold resource_lock

[Alistair Popple]

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().

Signed-off-by: Alistair Popple <apop...@nvidia.com>
---
 kernel/resource.c | 52 ++++++++++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 627e61b0c124..736768587d2d 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -523,6 +523,34 @@ 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
@@ -546,31 +574,13 @@ 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);
 
-- 
2.20.1