linux-kernel - [PATCH 20/53] sched/headers: Move in_vfork() from <linux/sched.h> to <linux/sched/mm.h>

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Message-Id: <1486579524-14901-21-git-send-email-mingo@kernel.org>
Date:   Wed,  8 Feb 2017 19:44:51 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Galbraith <efault@....de>,
        Oleg Nesterov <oleg@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 20/53] sched/headers: Move in_vfork() from <linux/sched.h> to <linux/sched/mm.h>

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

Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mike Galbraith <efault@....de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.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