5 files changed, 17 insertions, 7 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 89e4d4b145bb..1af022e63668 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3684,7 +3684,7 @@ F:	kernel/debug/
 
 KMEMCHECK
 M:      Vegard Nossum <vegardno@ifi.uio.no>
-M:      Pekka Enberg <penberg@cs.helsinki.fi>
+M:      Pekka Enberg <penberg@kernel.org>
 S:      Maintained
 F:      Documentation/kmemcheck.txt
 F:      arch/x86/include/asm/kmemcheck.h
@@ -5646,7 +5646,7 @@ F:	drivers/net/sky2.*
 
 SLAB ALLOCATOR
 M:      Christoph Lameter <cl@linux-foundation.org>
-M:      Pekka Enberg <penberg@cs.helsinki.fi>
+M:      Pekka Enberg <penberg@kernel.org>
 M:      Matt Mackall <mpm@selenic.com>
 L:      linux-mm@kvack.org
 S:      Maintained
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/slab.c b/mm/slab.c
index 264037449f08..37961d1f584f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -284,7 +284,7 @@ struct kmem_list3 {
  * Need this for bootstrapping a per node allocator.
  */
 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
-struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
+static struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
 #define CACHE_CACHE 0
 #define SIZE_AC MAX_NUMNODES
 #define SIZE_L3 (2 * MAX_NUMNODES)
@@ -4053,7 +4053,7 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
  * necessary. Note that the l3 listlock also protects the array_cache
  * if drain_array() is used on the shared array.
  */
-void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
+static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
                          struct array_cache *ac, int force, int node)
 {
         int tofree;
@@ -4317,7 +4317,7 @@ static const struct seq_operations slabinfo_op = {
  * @count: data length
  * @ppos: unused
  */
-ssize_t slabinfo_write(struct file *file, const char __user * buffer,
+static ssize_t slabinfo_write(struct file *file, const char __user *buffer,
                        size_t count, loff_t *ppos)
 {
         char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
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");
 }