Merge branch 'locking-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / kernel / resource.c

diff --git a/kernel/resource.c b/kernel/resource.c
index 60c5a38..4632201 100644 (file)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1245,6 +1245,76 @@ int release_mem_region_adjustable(struct resource *parent,
 /*
  * Managed region resource
  */
+static void devm_resource_release(struct device *dev, void *ptr)
+{
+       struct resource **r = ptr;
+
+       release_resource(*r);
+}
+
+/**
+ * devm_request_resource() - request and reserve an I/O or memory resource
+ * @dev: device for which to request the resource
+ * @root: root of the resource tree from which to request the resource
+ * @new: descriptor of the resource to request
+ *
+ * This is a device-managed version of request_resource(). There is usually
+ * no need to release resources requested by this function explicitly since
+ * that will be taken care of when the device is unbound from its driver.
+ * If for some reason the resource needs to be released explicitly, because
+ * of ordering issues for example, drivers must call devm_release_resource()
+ * rather than the regular release_resource().
+ *
+ * When a conflict is detected between any existing resources and the newly
+ * requested resource, an error message will be printed.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int devm_request_resource(struct device *dev, struct resource *root,
+                         struct resource *new)
+{
+       struct resource *conflict, **ptr;
+
+       ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
+       if (!ptr)
+               return -ENOMEM;
+
+       *ptr = new;
+
+       conflict = request_resource_conflict(root, new);
+       if (conflict) {
+               dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
+                       new, conflict->name, conflict);
+               devres_free(ptr);
+               return -EBUSY;
+       }
+
+       devres_add(dev, ptr);
+       return 0;
+}
+EXPORT_SYMBOL(devm_request_resource);
+
+static int devm_resource_match(struct device *dev, void *res, void *data)
+{
+       struct resource **ptr = res;
+
+       return *ptr == data;
+}
+
+/**
+ * devm_release_resource() - release a previously requested resource
+ * @dev: device for which to release the resource
+ * @new: descriptor of the resource to release
+ *
+ * Releases a resource previously requested using devm_request_resource().
+ */
+void devm_release_resource(struct device *dev, struct resource *new)
+{
+       WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
+                              new));
+}
+EXPORT_SYMBOL(devm_release_resource);
+
 struct region_devres {
        struct resource *parent;
        resource_size_t start;