[PATCH 20/53] sched/headers: Move in_vfork() from to

Ingo Molnar
2017-02-08T18:46:57Z

The in_vfork() function deals with task->mm, so it better belongs
into <linux/sched/mm.h>.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched.h | 26 --------------------------
include/linux/sched/mm.h | 26 ++++++++++++++++++++++++++
2 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0ba8596a4977..2e410594579c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1238,32 +1238,6 @@ static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
#define TNF_FAULT_LOCAL 0x08
#define TNF_MIGRATE_FAIL 0x10

-static inline bool in_vfork(struct task_struct *tsk)
-{
- bool ret;
-
- /*
- * need RCU to access ->real_parent if CLONE_VM was used along with
- * CLONE_PARENT.
- *
- * We check real_parent->mm == tsk->mm because CLONE_VFORK does not
- * imply CLONE_VM
- *
- * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus
- * ->real_parent is not necessarily the task doing vfork(), so in
- * theory we can't rely on task_lock() if we want to dereference it.
- *
- * And in this case we can't trust the real_parent->mm == tsk->mm
- * check, it can be false negative. But we do not care, if init or
- * another oom-unkillable task does this it should blame itself.
- */
- rcu_read_lock();
- ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm;
- rcu_read_unlock();
-
- return ret;
-}
-
#ifdef CONFIG_NUMA_BALANCING
extern void task_numa_fault(int last_node, int node, int pages, int flags);
extern pid_t task_numa_group_id(struct task_struct *p);
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 8fd3152bfeaa..5a01104e3e47 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -78,4 +78,30 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
#endif

+static inline bool in_vfork(struct task_struct *tsk)
+{
+ bool ret;
+
+ /*
+ * need RCU to access ->real_parent if CLONE_VM was used along with
+ * CLONE_PARENT.
+ *
+ * We check real_parent->mm == tsk->mm because CLONE_VFORK does not
+ * imply CLONE_VM
+ *
+ * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus
+ * ->real_parent is not necessarily the task doing vfork(), so in
+ * theory we can't rely on task_lock() if we want to dereference it.
+ *
+ * And in this case we can't trust the real_parent->mm == tsk->mm
+ * check, it can be false negative. But we do not care, if init or
+ * another oom-unkillable task does this it should blame itself.
+ */
+ rcu_read_lock();
+ ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm;
+ rcu_read_unlock();
+
+ return ret;
+}
+
#endif /* _LINUX_SCHED_MM_H */
--
2.7.4