Driver core: Add mutex for adding/removing memory blocks

Add a new mutex for use in adding and removing of memory blocks.  This
is needed to avoid any race conditions in which the same memory block could
be added and removed at the same time.

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>

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 63c25601572de00c98a331cea3d82666bad90c7a..5185bcff2de91f5216decd1c4614e9f1ab123cf1 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -27,6 +27,8 @@
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 
+static DEFINE_MUTEX(mem_sysfs_mutex);
+
 #define MEMORY_CLASS_NAME      "memory"
 
 static struct sysdev_class memory_sysdev_class = {
@@ -484,6 +486,8 @@ static int add_memory_block(int nid, struct mem_section *section,
        if (!mem)
                return -ENOMEM;
 
+       mutex_lock(&mem_sysfs_mutex);
+
        mem->phys_index = __section_nr(section);
        mem->state = state;
        mutex_init(&mem->state_mutex);
@@ -504,6 +508,7 @@ static int add_memory_block(int nid, struct mem_section *section,
                        ret = register_mem_sect_under_node(mem, nid);
        }
 
+       mutex_unlock(&mem_sysfs_mutex);
        return ret;
 }
 
@@ -512,6 +517,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
 {
        struct memory_block *mem;
 
+       mutex_lock(&mem_sysfs_mutex);
        mem = find_memory_block(section);
        unregister_mem_sect_under_nodes(mem);
        mem_remove_simple_file(mem, phys_index);
@@ -520,6 +526,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
        mem_remove_simple_file(mem, removable);
        unregister_memory(mem, section);
 
+       mutex_unlock(&mem_sysfs_mutex);
        return 0;
 }