resources: add interfaces that return conflict information
request_resource() and insert_resource() only return success or failure,
which no information about what existing resource conflicted with the
proposed new reservation. This patch adds request_resource_conflict()
and insert_resource_conflict(), which return the conflicting resource.
Callers may use this for better error messages or to adjust the new
resource and retry the request.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 71ab79d..26fad18 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -112,12 +112,14 @@
extern struct resource ioport_resource;
extern struct resource iomem_resource;
+extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
void release_child_resources(struct resource *new);
extern void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name);
+extern struct resource *insert_resource_conflict(struct resource *parent, struct resource *new);
extern int insert_resource(struct resource *parent, struct resource *new);
extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
extern int allocate_resource(struct resource *root, struct resource *new,
diff --git a/kernel/resource.c b/kernel/resource.c
index 2d5be5d..9c358e2 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -219,6 +219,23 @@
}
/**
+ * request_resource_conflict - request and reserve an I/O or memory resource
+ * @root: root resource descriptor
+ * @new: resource descriptor desired by caller
+ *
+ * Returns 0 for success, conflict resource on error.
+ */
+struct resource *request_resource_conflict(struct resource *root, struct resource *new)
+{
+ struct resource *conflict;
+
+ write_lock(&resource_lock);
+ conflict = __request_resource(root, new);
+ write_unlock(&resource_lock);
+ return conflict;
+}
+
+/**
* request_resource - request and reserve an I/O or memory resource
* @root: root resource descriptor
* @new: resource descriptor desired by caller
@@ -229,9 +246,7 @@
{
struct resource *conflict;
- write_lock(&resource_lock);
- conflict = __request_resource(root, new);
- write_unlock(&resource_lock);
+ conflict = request_resource_conflict(root, new);
return conflict ? -EBUSY : 0;
}
@@ -474,25 +489,40 @@
}
/**
- * insert_resource - Inserts a resource in the resource tree
+ * insert_resource_conflict - Inserts resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
- * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ * Returns 0 on success, conflict resource if the resource can't be inserted.
*
- * This function is equivalent to request_resource when no conflict
+ * This function is equivalent to request_resource_conflict when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
*/
-int insert_resource(struct resource *parent, struct resource *new)
+struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __insert_resource(parent, new);
write_unlock(&resource_lock);
+ return conflict;
+}
+
+/**
+ * insert_resource - Inserts a resource in the resource tree
+ * @parent: parent of the new resource
+ * @new: new resource to insert
+ *
+ * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ */
+int insert_resource(struct resource *parent, struct resource *new)
+{
+ struct resource *conflict;
+
+ conflict = insert_resource_conflict(parent, new);
return conflict ? -EBUSY : 0;
}