From 2a85caea22752506b8c8deb9edce0f41ffe1d02e Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 6 Jun 2011 12:20:33 +0200
Subject: sched-mmdrop-delayed.patch

Needs thread context (pgd_lock) -> ifdeffed. workqueues wont work with
RT

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/mm_types.h |  4 ++++
 include/linux/sched.h    | 12 ++++++++++++
 2 files changed, 16 insertions(+)

(limited to 'include')

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 1ec126f23eaa..c303a27981fe 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -12,6 +12,7 @@
 #include <linux/completion.h>
 #include <linux/cpumask.h>
 #include <linux/page-debug-flags.h>
+#include <linux/rcupdate.h>
 #include <asm/page.h>
 #include <asm/mmu.h>
 
@@ -393,6 +394,9 @@ struct mm_struct {
 #ifdef CONFIG_CPUMASK_OFFSTACK
 	struct cpumask cpumask_allocation;
 #endif
+#ifdef CONFIG_PREEMPT_RT_BASE
+	struct rcu_head delayed_drop;
+#endif
 };
 
 static inline void mm_init_cpumask(struct mm_struct *mm)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index fb5e51fc5af6..e6f37cacf751 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2268,12 +2268,24 @@ extern struct mm_struct * mm_alloc(void);
 
 /* mmdrop drops the mm and the page tables */
 extern void __mmdrop(struct mm_struct *);
+
 static inline void mmdrop(struct mm_struct * mm)
 {
 	if (unlikely(atomic_dec_and_test(&mm->mm_count)))
 		__mmdrop(mm);
 }
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+extern void __mmdrop_delayed(struct rcu_head *rhp);
+static inline void mmdrop_delayed(struct mm_struct *mm)
+{
+	if (atomic_dec_and_test(&mm->mm_count))
+		call_rcu(&mm->delayed_drop, __mmdrop_delayed);
+}
+#else
+# define mmdrop_delayed(mm)	mmdrop(mm)
+#endif
+
 /* mmput gets rid of the mappings and all user-space */
 extern void mmput(struct mm_struct *);
 /* Grab a reference to a task's mm, if it is not already going away */
-- 
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