[PATCH v1 3/7] resource: Introduce resource_union() for overlapping resources

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Some already present users may utilize resource_union() helper.
Provide it for them and for wider use in the future.

Deliberately avoid min()/max() macro as they are still parts of
kernel.h which is quite a burden to be included here in order
to avoid circular dependencies.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
---
 include/linux/ioport.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 0193987b9968..c98df0ec7422 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -232,6 +232,16 @@ static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
        return (r1->start <= r2->end && r1->end >= r2->start);
 }
 
+static inline bool
+resource_union(struct resource *r1, struct resource *r2, struct resource *r)
+{
+	if (!resource_overlaps(r1, r2))
+		return false;
+	r->start = r2->start < r1->start ? r2->start : r1->start;
+	r->end = r2->end > r1->end ? r2->end : r1->end;
+	return true;
+}
+
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)		__request_region(&ioport_resource, (start), (n), (name), 0)
 #define request_muxed_region(start,n,name)	__request_region(&ioport_resource, (start), (n), (name), IORESOURCE_MUXED)
-- 
2.28.0