Driver core: Add section count to memory_block struct

Add a section count property to the memory_block struct to track the number
of memory sections that have been added/removed from a memory block. This
allows us to know when the last memory section of a memory block has been
removed so we can remove the memory block.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Reviewed-by: Robin Holt <holt@sgi.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 13 insertions, 6 deletions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 5185bcff2de9..cafeaaf0428f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -490,6 +490,7 @@ static int add_memory_block(int nid, struct mem_section *section,
 
         mem->phys_index = __section_nr(section);
         mem->state = state;
+        mem->section_count++;
         mutex_init(&mem->state_mutex);
         start_pfn = section_nr_to_pfn(mem->phys_index);
         mem->phys_device = arch_get_memory_phys_device(start_pfn);
@@ -519,12 +520,16 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
 
         mutex_lock(&mem_sysfs_mutex);
         mem = find_memory_block(section);
-        unregister_mem_sect_under_nodes(mem);
-        mem_remove_simple_file(mem, phys_index);
-        mem_remove_simple_file(mem, state);
-        mem_remove_simple_file(mem, phys_device);
-        mem_remove_simple_file(mem, removable);
-        unregister_memory(mem, section);
+
+        mem->section_count--;
+        if (mem->section_count == 0) {
+                unregister_mem_sect_under_nodes(mem);
+                mem_remove_simple_file(mem, phys_index);
+                mem_remove_simple_file(mem, state);
+                mem_remove_simple_file(mem, phys_device);
+                mem_remove_simple_file(mem, removable);
+                unregister_memory(mem, section);
+        }
 
         mutex_unlock(&mem_sysfs_mutex);
         return 0;
diff --git a/include/linux/memory.h b/include/linux/memory.h
index c4f3127dbd48..06c1fa0a5c7b 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -23,6 +23,8 @@
 struct memory_block {
         unsigned long phys_index;
         unsigned long state;
+        int section_count;
+
         /*
          * This serializes all state change requests.  It isn't
          * held during creation because the control files are