Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

[powerpc.git] / drivers / oprofile / buffer_sync.c

diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index 531b073..b2e8e49 100644 (file)
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -43,13 +43,16 @@ static void process_task_mortuary(void);
  * list for processing. Only after two full buffer syncs
  * does the task eventually get freed, because by then
  * we are sure we will not reference it again.
+ * Can be invoked from softirq via RCU callback due to
+ * call_rcu() of the task struct, hence the _irqsave.
  */
 static int task_free_notify(struct notifier_block * self, unsigned long val, void * data)
 {
+       unsigned long flags;
        struct task_struct * task = data;
-       spin_lock(&task_mortuary);
+       spin_lock_irqsave(&task_mortuary, flags);
        list_add(&task->tasks, &dying_tasks);
-       spin_unlock(&task_mortuary);
+       spin_unlock_irqrestore(&task_mortuary, flags);
        return NOTIFY_OK;
 }
 
@@ -431,25 +434,22 @@ static void increment_tail(struct oprofile_cpu_buffer * b)
  */
 static void process_task_mortuary(void)
 {
-       struct list_head * pos;
-       struct list_head * pos2;
+       unsigned long flags;
+       LIST_HEAD(local_dead_tasks);
        struct task_struct * task;
+       struct task_struct * ttask;
 
-       spin_lock(&task_mortuary);
+       spin_lock_irqsave(&task_mortuary, flags);
 
-       list_for_each_safe(pos, pos2, &dead_tasks) {
-               task = list_entry(pos, struct task_struct, tasks);
-               list_del(&task->tasks);
-               free_task(task);
-       }
+       list_splice_init(&dead_tasks, &local_dead_tasks);
+       list_splice_init(&dying_tasks, &dead_tasks);
 
-       list_for_each_safe(pos, pos2, &dying_tasks) {
-               task = list_entry(pos, struct task_struct, tasks);
+       spin_unlock_irqrestore(&task_mortuary, flags);
+
+       list_for_each_entry_safe(task, ttask, &local_dead_tasks, tasks) {
                list_del(&task->tasks);
-               list_add_tail(&task->tasks, &dead_tasks);
+               free_task(task);
        }
-
-       spin_unlock(&task_mortuary);
 }