resource: Add __resource_contains_unbound() for internal contains checks

__find_resource_space() currently uses resource_contains() but for
tentative resources that are not yet crafted into the resource tree. As
resource_contains() checks that IORESOURCE_UNSET is not set for either of
the resources, the caller has to hack around this problem by clearing the
IORESOURCE_UNSET flag (essentially lying to resource_contains()).

Instead of the hack, introduce __resource_contains_unbound() for cases like
this.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Xifer <xiferdev@gmail.com>
Link: https://patch.msgid.link/20260324165633.4583-2-ilpo.jarvinen@linux.intel.com

2 files changed, 19 insertions, 5 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 5533a5debf3f..19d5e04564d9 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -304,14 +304,28 @@ static inline unsigned long resource_ext_type(const struct resource *res)
 {
 	return res->flags & IORESOURCE_EXT_TYPE_BITS;
 }
-/* True iff r1 completely contains r2 */
-static inline bool resource_contains(const struct resource *r1, const struct resource *r2)
+
+/*
+ * For checking if @r1 completely contains @r2 for resources that have real
+ * addresses but are not yet crafted into the resource tree. Normally
+ * resource_contains() should be used instead of this function as it checks
+ * also IORESOURCE_UNSET flag.
+ */
+static inline bool __resource_contains_unbound(const struct resource *r1,
+					       const struct resource *r2)
 {
 	if (resource_type(r1) != resource_type(r2))
 		return false;
+
+	return r1->start <= r2->start && r1->end >= r2->end;
+}
+/* True iff r1 completely contains r2 */
+static inline bool resource_contains(const struct resource *r1, const struct resource *r2)
+{
 	if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
 		return false;
-	return r1->start <= r2->start && r1->end >= r2->end;
+
+	return __resource_contains_unbound(r1, r2);
 }
 
 /* True if any part of r1 overlaps r2 */
diff --git a/kernel/resource.c b/kernel/resource.c
index bb966699da31..1e2f1dfc0edd 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -754,7 +754,7 @@ static int __find_resource_space(struct resource *root, struct resource *old,
 		/* Check for overflow after ALIGN() */
 		avail.start = ALIGN(tmp.start, constraint->align);
 		avail.end = tmp.end;
-		avail.flags = new->flags & ~IORESOURCE_UNSET;
+		avail.flags = new->flags;
 		if (avail.start >= tmp.start) {
 			alloc.flags = avail.flags;
 			if (alignf) {
@@ -765,7 +765,7 @@ static int __find_resource_space(struct resource *root, struct resource *old,
 			}
 			alloc.end = alloc.start + size - 1;
 			if (alloc.start <= alloc.end &&
-			    resource_contains(&avail, &alloc)) {
+			    __resource_contains_unbound(&avail, &alloc)) {
 				new->start = alloc.start;
 				new->end = alloc.end;
 				return 0;