On Wed, Jul 18, 2018 at 5:49 AM, Baoquan He [off-list ref] wrote:

reparent_resources() is duplicated in arch/microblaze/pci/pci-common.c
and arch/powerpc/kernel/pci-common.c, so move it to kernel/resource.c
so that it's shared.

Some minor stuff.

+/**
+ * reparent_resources - reparent resource children of parent that res covers
+ * @parent: parent resource descriptor
+ * @res: resource descriptor desired by caller
+ *
+ * Returns 0 on success, -ENOTSUPP if child resource is not completely
+ * contained by 'res', -ECANCELED if no any conflicting entry found.

'res' -> @res

+ *
+ * Reparent resource children of 'parent' that conflict with 'res'

Ditto + 'parent' -> @parent

+ * under 'res', and make 'res' replace those children.

Ditto.

+ */
+int reparent_resources(struct resource *parent, struct resource *res)
+{
+       struct resource *p, **pp;
+       struct resource **firstpp = NULL;
+
+       for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
+               if (p->end < res->start)
+                       continue;
+               if (res->end < p->start)
+                       break;
+               if (p->start < res->start || p->end > res->end)
+                       return -ENOTSUPP;       /* not completely contained */
+               if (firstpp == NULL)
+                       firstpp = pp;
+       }
+       if (firstpp == NULL)
+               return -ECANCELED; /* didn't find any conflicting entries? */
+       res->parent = parent;
+       res->child = *firstpp;
+       res->sibling = *pp;
+       *firstpp = res;
+       *pp = NULL;
+       for (p = res->child; p != NULL; p = p->sibling) {
+               p->parent = res;

+               pr_debug("PCI: Reparented %s %pR under %s\n",
+                        p->name, p, res->name);

Now, PCI is a bit confusing here.

+       }
+       return 0;
+}
+EXPORT_SYMBOL(reparent_resources);
+
 static void __init __reserve_region_with_split(struct resource *root,
                resource_size_t start, resource_size_t end,
                const char *name)
--
2.13.6

-- 
With Best Regards,
Andy Shevchenko