edac,rcu: use synchronize_rcu() instead of call_rcu()+rcu_barrier()

synchronize_rcu() does the stuff as needed.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/edac/edac_core.h

@@ -421,10 +421,6 @@ struct mem_ctl_info {
 	u32 ce_count;		/* Total Correctable Errors for this MC */
 	unsigned long start_time;	/* mci load start time (in jiffies) */
 
-	/* this stuff is for safe removal of mc devices from global list while
-	 * NMI handlers may be traversing list
-	 */
-	struct rcu_head rcu;
 	struct completion complete;
 
 	/* edac sysfs device control */
@@ -620,10 +616,6 @@ struct edac_device_ctl_info {
 
 	unsigned long start_time;	/* edac_device load start time (jiffies) */
 
-	/* these are for safe removal of mc devices from global list while
-	 * NMI handlers may be traversing list
-	 */
-	struct rcu_head rcu;
 	struct completion removal_complete;
 
 	/* sysfs top name under 'edac' directory
@@ -722,10 +714,6 @@ struct edac_pci_ctl_info {
 
 	unsigned long start_time;	/* edac_pci load start time (jiffies) */
 
-	/* these are for safe removal of devices from global list while
-	 * NMI handlers may be traversing list
-	 */
-	struct rcu_head rcu;
 	struct completion complete;
 
 	/* sysfs top name under 'edac' directory

drivers/edac/edac_device.c

@@ -345,31 +345,19 @@ static int add_edac_dev_to_global_list(struct edac_device_ctl_info *edac_dev)
 	return 1;
 }
 
-/*
- * complete_edac_device_list_del
- *
- *	callback function when reference count is zero
- */
-static void complete_edac_device_list_del(struct rcu_head *head)
-{
-	struct edac_device_ctl_info *edac_dev;
-
-	edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
-	INIT_LIST_HEAD(&edac_dev->link);
-}
-
 /*
  * del_edac_device_from_global_list
- *
- *	remove the RCU, setup for a callback call,
- *	then wait for the callback to occur
  */
 static void del_edac_device_from_global_list(struct edac_device_ctl_info
 						*edac_device)
 {
 	list_del_rcu(&edac_device->link);
-	call_rcu(&edac_device->rcu, complete_edac_device_list_del);
-	rcu_barrier();
+
+	/* these are for safe removal of devices from global list while
+	 * NMI handlers may be traversing list
+	 */
+	synchronize_rcu();
+	INIT_LIST_HEAD(&edac_device->link);
 }
 
 /*

drivers/edac/edac_mc.c

@@ -447,20 +447,16 @@ static int add_mc_to_global_list(struct mem_ctl_info *mci)
 	return 1;
 }
 
-static void complete_mc_list_del(struct rcu_head *head)
-{
-	struct mem_ctl_info *mci;
-
-	mci = container_of(head, struct mem_ctl_info, rcu);
-	INIT_LIST_HEAD(&mci->link);
-}
-
 static void del_mc_from_global_list(struct mem_ctl_info *mci)
 {
 	atomic_dec(&edac_handlers);
 	list_del_rcu(&mci->link);
-	call_rcu(&mci->rcu, complete_mc_list_del);
-	rcu_barrier();
+
+	/* these are for safe removal of devices from global list while
+	 * NMI handlers may be traversing list
+	 */
+	synchronize_rcu();
+	INIT_LIST_HEAD(&mci->link);
 }
 
 /**

drivers/edac/edac_pci.c

@@ -163,19 +163,6 @@ static int add_edac_pci_to_global_list(struct edac_pci_ctl_info *pci)
 	return 1;
 }
 
-/*
- * complete_edac_pci_list_del
- *
- *	RCU completion callback to indicate item is deleted
- */
-static void complete_edac_pci_list_del(struct rcu_head *head)
-{
-	struct edac_pci_ctl_info *pci;
-
-	pci = container_of(head, struct edac_pci_ctl_info, rcu);
-	INIT_LIST_HEAD(&pci->link);
-}
-
 /*
  * del_edac_pci_from_global_list
  *
@@ -184,8 +171,12 @@ static void complete_edac_pci_list_del(struct rcu_head *head)
 static void del_edac_pci_from_global_list(struct edac_pci_ctl_info *pci)
 {
 	list_del_rcu(&pci->link);
-	call_rcu(&pci->rcu, complete_edac_pci_list_del);
-	rcu_barrier();
+
+	/* these are for safe removal of devices from global list while
+	 * NMI handlers may be traversing list
+	 */
+	synchronize_rcu();
+	INIT_LIST_HEAD(&pci->link);
 }
 
 #if 0