Patch "sched/core: Add switch_mm_irqs_off() and use it in the scheduler" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

sched/core: Add switch_mm_irqs_off() and use it in the scheduler

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
sched-core-add-switch_mm_irqs_off-and-use-it-in-the-scheduler.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Andy Lutomirski <[email protected]>
Date: Tue, 26 Apr 2016 09:39:06 -0700
Subject: sched/core: Add switch_mm_irqs_off() and use it in the scheduler

From: Andy Lutomirski <[email protected]>

commit f98db6013c557c216da5038d9c52045be55cd039 upstream.

By default, this is the same thing as switch_mm().

x86 will override it as an optimization.

---
 include/linux/mmu_context.h |    7 +++++++
 kernel/sched/core.c         |    6 +++---
 2 files changed, 10 insertions(+), 3 deletions(-)

@@ -1,9 +1,16 @@
 #ifndef _LINUX_MMU_CONTEXT_H
 #define _LINUX_MMU_CONTEXT_H
 
+#include <asm/mmu_context.h>
+
 struct mm_struct;
 
 void use_mm(struct mm_struct *mm);
 void unuse_mm(struct mm_struct *mm);
 
+/* Architectures that care about IRQ state in switch_mm can override this. */
+#ifndef switch_mm_irqs_off
+# define switch_mm_irqs_off switch_mm
+#endif
+
 #endif

@@ -32,7 +32,7 @@
 #include <linux/init.h>
 #include <linux/uaccess.h>
 #include <linux/highmem.h>
-#include <asm/mmu_context.h>
+#include <linux/mmu_context.h>
 #include <linux/interrupt.h>
 #include <linux/capability.h>
 #include <linux/completion.h>

@@ -2708,7 +2708,7 @@ context_switch(struct rq *rq, struct tas
 		atomic_inc(&oldmm->mm_count);
 		enter_lazy_tlb(oldmm, next);
 	} else
-		switch_mm(oldmm, mm, next);
+		switch_mm_irqs_off(oldmm, mm, next);
 
 	if (!prev->mm) {
 		prev->active_mm = NULL;

@@ -5206,7 +5206,7 @@ void idle_task_exit(void)
 	BUG_ON(cpu_online(smp_processor_id()));
 
 	if (mm != &init_mm) {
-		switch_mm(mm, &init_mm, current);
+		switch_mm_irqs_off(mm, &init_mm, current);
 		finish_arch_post_lock_switch();
 	}
 	mmdrop(mm);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/x86-mm-sched-core-uninline-switch_mm.patch queue-4.4/x86-mm-add-a-noinvpcid-boot-option-to-turn-off-invpcid.patch queue-4.4/x86-irq-do-not-substract-irq_tlb_count-from-irq_call_count.patch queue-4.4/x86-mm-if-invpcid-is-available-use-it-to-flush-global-mappings.patch queue-4.4/x86-mm-add-invpcid-helpers.patch queue-4.4/sched-core-add-switch_mm_irqs_off-and-use-it-in-the-scheduler.patch queue-4.4/arm-hide-finish_arch_post_lock_switch-from-modules.patch queue-4.4/x86-mm-sched-core-turn-off-irqs-in-switch_mm.patch queue-4.4/mm-mmu_context-sched-core-fix-mmu_context.h-assumption.patch queue-4.4/x86-mm-build-arch-x86-mm-tlb.c-even-on-smp.patch queue-4.4/sched-core-idle_task_exit-shouldn-t-use-switch_mm_irqs_off.patch