resource: Add resource_contains()

We have two identical copies of resource_contains() already, and more
places that could use it.  This moves it to ioport.h where it can be
shared.

resource_contains(struct resource *r1, struct resource *r2) returns true
iff r1 and r2 are the same type (most callers already checked this
separately) and the r1 address range completely contains r2.

In addition, the new resource_contains() checks that both r1 and r2 have
addresses assigned to them.  If a resource is IORESOURCE_UNSET, it doesn't
have a valid address and can't contain or be contained by another resource.
Some callers already check this or for res->start.

No functional change.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 89b7c24a36e9..9fcaac8bc4f6 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -169,6 +169,16 @@ static inline unsigned long resource_type(const struct resource *res)
 {
 	return res->flags & IORESOURCE_TYPE_BITS;
 }
+/* True iff r1 completely contains r2 */
+static inline bool resource_contains(struct resource *r1, struct resource *r2)
+{
+	if (resource_type(r1) != resource_type(r2))
+		return false;
+	if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
+		return false;
+	return r1->start <= r2->start && r1->end >= r2->end;
+}
+
 
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)		__request_region(&ioport_resource, (start), (n), (name), 0)