[3/8] v2 Add mutex for adding/removing memory blocks

Submitted by Nathan Fontenot on Sept. 27, 2010, 7:23 p.m.

Details

Message ID 4CA0EF45.3000601@austin.ibm.com
State Not Applicable
Headers show

Commit Message

Nathan Fontenot Sept. 27, 2010, 7:23 p.m. 
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>

---
 drivers/base/memory.c |    7 +++++++
 1 file changed, 7 insertions(+)

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Index: linux-next/drivers/base/memory.c
===================================================================
--- linux-next.orig/drivers/base/memory.c	2010-09-27 09:31:35.000000000 -0500
+++ linux-next/drivers/base/memory.c	2010-09-27 09:31:57.000000000 -0500
@@ -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 = {
@@ -476,6 +478,8 @@ 
 	if (!mem)
 		return -ENOMEM;
 
+	mutex_lock(&mem_sysfs_mutex);
+
 	mem->phys_index = __section_nr(section);
 	mem->state = state;
 	atomic_inc(&mem->section_count);
@@ -497,6 +501,7 @@ 
 			ret = register_mem_sect_under_node(mem, nid);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return ret;
 }
 
@@ -505,6 +510,7 @@ 
 {
 	struct memory_block *mem;
 
+	mutex_lock(&mem_sysfs_mutex);
 	mem = find_memory_block(section);
 
 	if (atomic_dec_and_test(&mem->section_count)) {
@@ -516,6 +522,7 @@ 
 		unregister_memory(mem, section);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return 0;
 }