X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Ffreezer.c;h=a8900a3bc27a895b65580a23a144e581bfe0149d;hb=574b2e2aff5afc7a38d1ce3ac5912733fff1670e;hp=bd733f6e610d053fbe857aca9828a9c9a8e30706;hpb=13beb8851e931b3cfb3403c3a62bfee9ab27a60c;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/freezer.c b/kernel/freezer.c
index bd733f6e610d..a8900a3bc27a 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -39,7 +39,7 @@ static DEFINE_SPINLOCK(freezer_lock);
  */
 bool freezing_slow_path(struct task_struct *p)
 {
-	if (p->flags & PF_NOFREEZE)
+	if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
 		return false;
 
 	if (test_thread_flag(TIF_MEMDIE))
@@ -119,6 +119,18 @@ bool freeze_task(struct task_struct *p)
 {
 	unsigned long flags;
 
+	/*
+	 * This check can race with freezer_do_not_count, but worst case that
+	 * will result in an extra wakeup being sent to the task.  It does not
+	 * race with freezer_count(), the barriers in freezer_count() and
+	 * freezer_should_skip() ensure that either freezer_count() sees
+	 * freezing == true in try_to_freeze() and freezes, or
+	 * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
+	 * normally.
+	 */
+	if (freezer_should_skip(p))
+		return false;
+
 	spin_lock_irqsave(&freezer_lock, flags);
 	if (!freezing(p) || frozen(p)) {
 		spin_unlock_irqrestore(&freezer_lock, flags);
@@ -138,12 +150,6 @@ void __thaw_task(struct task_struct *p)
 {
 	unsigned long flags;
 
-	/*
-	 * Clear freezing and kick @p if FROZEN.  Clearing is guaranteed to
-	 * be visible to @p as waking up implies wmb.  Waking up inside
-	 * freezer_lock also prevents wakeups from leaking outside
-	 * refrigerator.
-	 */
 	spin_lock_irqsave(&freezer_lock, flags);
 	if (frozen(p))
 		wake_up_process(p);