1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 91636cd8b6c9..43fa90b837ee 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/mm.h>
+#include <linux/memory.h>
 #include <linux/node.h>
 #include <linux/hugetlb.h>
 #include <linux/cpumask.h>
@@ -248,6 +249,105 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
         return 0;
 }
 
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+#define page_initialized(page)  (page->lru.next)
+
+static int get_nid_for_pfn(unsigned long pfn)
+{
+        struct page *page;
+
+        if (!pfn_valid_within(pfn))
+                return -1;
+        page = pfn_to_page(pfn);
+        if (!page_initialized(page))
+                return -1;
+        return pfn_to_nid(pfn);
+}
+
+/* register memory section under specified node if it spans that node */
+int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
+{
+        unsigned long pfn, sect_start_pfn, sect_end_pfn;
+
+        if (!mem_blk)
+                return -EFAULT;
+        if (!node_online(nid))
+                return 0;
+        sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
+        sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
+        for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
+                int page_nid;
+
+                page_nid = get_nid_for_pfn(pfn);
+                if (page_nid < 0)
+                        continue;
+                if (page_nid != nid)
+                        continue;
+                return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
+                                        &mem_blk->sysdev.kobj,
+                                        kobject_name(&mem_blk->sysdev.kobj));
+        }
+        /* mem section does not span the specified node */
+        return 0;
+}
+
+/* unregister memory section under all nodes that it spans */
+int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
+{
+        nodemask_t unlinked_nodes;
+        unsigned long pfn, sect_start_pfn, sect_end_pfn;
+
+        if (!mem_blk)
+                return -EFAULT;
+        nodes_clear(unlinked_nodes);
+        sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
+        sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
+        for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
+                unsigned int nid;
+
+                nid = get_nid_for_pfn(pfn);
+                if (nid < 0)
+                        continue;
+                if (!node_online(nid))
+                        continue;
+                if (node_test_and_set(nid, unlinked_nodes))
+                        continue;
+                sysfs_remove_link(&node_devices[nid].sysdev.kobj,
+                         kobject_name(&mem_blk->sysdev.kobj));
+        }
+        return 0;
+}
+
+static int link_mem_sections(int nid)
+{
+        unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+        unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+        unsigned long pfn;
+        int err = 0;
+
+        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+                unsigned long section_nr = pfn_to_section_nr(pfn);
+                struct mem_section *mem_sect;
+                struct memory_block *mem_blk;
+                int ret;
+
+                if (!present_section_nr(section_nr))
+                        continue;
+                mem_sect = __nr_to_section(section_nr);
+                mem_blk = find_memory_block(mem_sect);
+                ret = register_mem_sect_under_node(mem_blk, nid);
+                if (!err)
+                        err = ret;
+
+                /* discard ref obtained in find_memory_block() */
+                kobject_put(&mem_blk->sysdev.kobj);
+        }
+        return err;
+}
+#else
+static int link_mem_sections(int nid) { return 0; }
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
 int register_one_node(int nid)
 {
         int error = 0;
@@ -267,6 +367,9 @@ int register_one_node(int nid)
                         if (cpu_to_node(cpu) == nid)
                                 register_cpu_under_node(cpu, nid);
                 }
+
+                /* link memory sections under this node */
+                error = link_mem_sections(nid);
         }
 
         return error;