resources: add resource_overlaps()

Add resource_overlaps(), which returns true if two resources overlap at all.

Use this to replace the complicated check in coalesce_windows().
Signed-Off-By: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/x86/pci/acpi.c

@@ -245,13 +245,6 @@ setup_resource(struct acpi_resource *acpi_res, void *data)
 	return AE_OK;
 }
 
-static bool resource_contains(struct resource *res, resource_size_t point)
-{
-	if (res->start <= point && point <= res->end)
-		return true;
-	return false;
-}
-
 static void coalesce_windows(struct pci_root_info *info, unsigned long type)
 {
 	int i, j;
@@ -272,10 +265,7 @@ static void coalesce_windows(struct pci_root_info *info, unsigned long type)
 			 * our resources no longer match the ACPI _CRS, but
 			 * the kernel resource tree doesn't allow overlaps.
 			 */
-			if (resource_contains(res1, res2->start) ||
-			    resource_contains(res1, res2->end) ||
-			    resource_contains(res2, res1->start) ||
-			    resource_contains(res2, res1->end)) {
+			if (resource_overlaps(res1, res2)) {
 				res1->start = min(res1->start, res2->start);
 				res1->end = max(res1->end, res2->end);
 				dev_info(&info->bridge->dev,

include/linux/ioport.h

@@ -223,5 +223,12 @@ extern int
 walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 		void *arg, int (*func)(unsigned long, unsigned long, void *));
 
+/* True if any part of r1 overlaps r2 */
+static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
+{
+       return (r1->start <= r2->end && r1->end >= r2->start);
+}
+
+
 #endif /* __ASSEMBLY__ */
 #endif	/* _LINUX_IOPORT_H */