Patchwork [4/8] Add mutex for adding/removing memory blocks

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Submitter Nathan Fontenot
Date Sept. 22, 2010, 2:32 p.m.
Message ID <4C9A1360.6030800@austin.ibm.com>
Download mbox | patch
Permalink /patch/65425/
State Superseded
Headers show

Comments

Nathan Fontenot - Sept. 22, 2010, 2:32 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(+)

Patch

Index: linux-next/drivers/base/memory.c
===================================================================
--- linux-next.orig/drivers/base/memory.c	2010-09-21 12:36:45.000000000 -0500
+++ linux-next/drivers/base/memory.c	2010-09-21 12:37:03.000000000 -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 = {
@@ -485,6 +487,8 @@  static int add_memory_block(int nid, str
 	if (!mem)
 		return -ENOMEM;
 
+	mutex_lock(&mem_sysfs_mutex);
+
 	mem->start_phys_index = __section_nr(section);
 	mem->state = state;
 	atomic_inc(&mem->section_count);
@@ -508,6 +512,7 @@  static int add_memory_block(int nid, str
 			ret = register_mem_sect_under_node(mem, nid);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return ret;
 }
 
@@ -516,6 +521,7 @@  int remove_memory_block(unsigned long no
 {
 	struct memory_block *mem;
 
+	mutex_lock(&mem_sysfs_mutex);
 	mem = find_memory_block(section);
 
 	if (atomic_dec_and_test(&mem->section_count)) {
@@ -528,6 +534,7 @@  int remove_memory_block(unsigned long no
 		unregister_memory(mem, section);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return 0;
 }