[PATCH] catch valid mem range at onlining memory

[linux-block.git] / kernel / resource.c

diff --git a/kernel/resource.c b/kernel/resource.c
index e3080fcc66a3b1237e30326782eed2a8fd184323..2404f9b0bc4772411adf8a8e69076642e6ded487 100644 (file)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -232,6 +232,44 @@ int release_resource(struct resource *old)
 
 EXPORT_SYMBOL(release_resource);
 
+#ifdef CONFIG_MEMORY_HOTPLUG
+/*
+ * Finds the lowest memory reosurce exists within [res->start.res->end)
+ * the caller must specify res->start, res->end, res->flags.
+ * If found, returns 0, res is overwritten, if not found, returns -1.
+ */
+int find_next_system_ram(struct resource *res)
+{
+       resource_size_t start, end;
+       struct resource *p;
+
+       BUG_ON(!res);
+
+       start = res->start;
+       end = res->end;
+
+       read_lock(&resource_lock);
+       for (p = iomem_resource.child; p ; p = p->sibling) {
+               /* system ram is just marked as IORESOURCE_MEM */
+               if (p->flags != res->flags)
+                       continue;
+               if (p->start > end) {
+                       p = NULL;
+                       break;
+               }
+               if (p->start >= start)
+                       break;
+       }
+       read_unlock(&resource_lock);
+       if (!p)
+               return -1;
+       /* copy data */
+       res->start = p->start;
+       res->end = p->end;
+       return 0;
+}
+#endif
+
 /*
  * Find empty slot in the resource tree given range and alignment.
  */