[PATCH v7 15/22] freezer: Add frozen_or_skipped() helper function

Will Deacon
2021-05-25T15:29:37Z

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@kernel.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
--
2.31.1.818.g46aad6cb9e-goog