linux-kernel - [PATCH v6 14/21] freezer: Add frozen_or

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Date:   Tue, 18 May 2021 10:47:18 +0100
From:   Will Deacon <will@...nel.org>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Marc Zyngier <maz@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Qais Yousef <qais.yousef@....com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Quentin Perret <qperret@...gle.com>, Tejun Heo <tj@...nel.org>,
        Li Zefan <lizefan@...wei.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Ingo Molnar <mingo@...hat.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, kernel-team@...roid.com
Subject: [PATCH v6 14/21] freezer: Add frozen_or_skipped() helper function

Occasionally it is necessary to see if a task is either frozen or
sleeping in the PF_FREEZER_SKIP state. In preparation for adding
additional users of this check, introduce a frozen_or_skipped() helper
function and convert the hung task detector over to using it.

Signed-off-by: Will Deacon <will@...nel.org>
---
 include/linux/freezer.h | 6 ++++++
 kernel/hung_task.c      | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 0621c5f86c39..b9e1e4200101 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -27,6 +27,11 @@ static inline bool frozen(struct task_struct *p)
 	return p->flags & PF_FROZEN;
 }
 
+static inline bool frozen_or_skipped(struct task_struct *p)
+{
+	return p->flags & (PF_FROZEN | PF_FREEZER_SKIP);
+}
+
 extern bool freezing_slow_path(struct task_struct *p);
 
 /*
@@ -270,6 +275,7 @@ static inline int freezable_schedule_hrtimeout_range(ktime_t *expires,
 
 #else /* !CONFIG_FREEZER */
 static inline bool frozen(struct task_struct *p) { return false; }
+static inline bool frozen_or_skipped(struct task_struct *p) { return false; }
 static inline bool freezing(struct task_struct *p) { return false; }
 static inline void __thaw_task(struct task_struct *t) {}
 
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 396ebaebea3f..d2d4c4159b23 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -92,8 +92,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 	 * Ensure the task is not frozen.
 	 * Also, skip vfork and any other user process that freezer should skip.
 	 */
-	if (unlikely(t->flags & (PF_FROZEN | PF_FREEZER_SKIP)))
-	    return;
+	if (unlikely(frozen_or_skipped(t)))
+		return;
 
 	/*
 	 * When a freshly created task is scheduled once, changes its state to
-- 
2.31.1.751.gd2f1c929bd-goog