Merge tag 'ftracetest-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...

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

diff --git a/kernel/resource.c b/kernel/resource.c
index da14b8d092961bf5680bf06004f980ad1ec43859..46322019ab7d388ad62029b42248d2c0a5ecaf72 100644 (file)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -351,15 +351,12 @@ static int find_next_iomem_res(struct resource *res, char *name,
        end = res->end;
        BUG_ON(start >= end);
 
-       read_lock(&resource_lock);
-
-       if (first_level_children_only) {
-               p = iomem_resource.child;
+       if (first_level_children_only)
                sibling_only = true;
-       } else
-               p = &iomem_resource;
 
-       while ((p = next_resource(p, sibling_only))) {
+       read_lock(&resource_lock);
+
+       for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
                if (p->flags != res->flags)
                        continue;
                if (name && strcmp(p->name, name))
@@ -1248,6 +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;