Merge branch 'slub/hotplug' into slab/urgent

3 files changed, 12 insertions, 2 deletions

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 24376fe7ee68..8122018d3000 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -165,6 +165,12 @@ extern void register_page_bootmem_info_node(struct pglist_data *pgdat);
 extern void put_page_bootmem(struct page *page);
 #endif
 
+/*
+ * Lock for memory hotplug guarantees 1) all callbacks for memory hotplug
+ * notifier will be called under this. 2) offline/online/add/remove memory
+ * will not run simultaneously.
+ */
+
 void lock_memory_hotplug(void);
 void unlock_memory_hotplug(void);
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e92f04749fcb..321fc7455df7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -409,6 +409,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
         int ret;
         struct memory_notify arg;
 
+        lock_memory_hotplug();
         arg.start_pfn = pfn;
         arg.nr_pages = nr_pages;
         arg.status_change_nid = -1;
@@ -421,6 +422,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
         ret = notifier_to_errno(ret);
         if (ret) {
                 memory_notify(MEM_CANCEL_ONLINE, &arg);
+                unlock_memory_hotplug();
                 return ret;
         }
         /*
@@ -445,6 +447,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
                 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
                         nr_pages, pfn);
                 memory_notify(MEM_CANCEL_ONLINE, &arg);
+                unlock_memory_hotplug();
                 return ret;
         }
 
@@ -469,6 +472,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
 
         if (onlined_pages)
                 memory_notify(MEM_ONLINE, &arg);
+        unlock_memory_hotplug();
 
         return 0;
 }
diff --git a/mm/slub.c b/mm/slub.c
index c7ef0070dd86..e15aa7f193c9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3797,7 +3797,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
                 }
         }
 
-        down_read(&slub_lock);
+        lock_memory_hotplug();
 #ifdef CONFIG_SLUB_DEBUG
         if (flags & SO_ALL) {
                 for_each_node_state(node, N_NORMAL_MEMORY) {
@@ -3838,7 +3838,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
                         x += sprintf(buf + x, " N%d=%lu",
                                         node, nodes[node]);
 #endif
-        up_read(&slub_lock);
+        unlock_memory_hotplug();
         kfree(nodes);
         return x + sprintf(buf + x, "\n");
 }