Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / mm / mmu_context.c

diff --git a/kernel/mm/mmu_context.c b/kernel/mm/mmu_context.c
new file mode 100644 (file)
index 0000000..b1b6f23
--- /dev/null
+++ b/kernel/mm/mmu_context.c
@@ -0,0 +1,64 @@
+/* Copyright (C) 2009 Red Hat, Inc.
+ *
+ * See ../COPYING for licensing terms.
+ */
+
+#include <linux/mm.h>
+#include <linux/mmu_context.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+
+#include <asm/mmu_context.h>
+
+/*
+ * use_mm
+ *     Makes the calling kernel thread take on the specified
+ *     mm context.
+ *     (Note: this routine is intended to be called only
+ *     from a kernel thread context)
+ */
+void use_mm(struct mm_struct *mm)
+{
+       struct mm_struct *active_mm;
+       struct task_struct *tsk = current;
+
+       task_lock(tsk);
+       preempt_disable_rt();
+       active_mm = tsk->active_mm;
+       if (active_mm != mm) {
+               atomic_inc(&mm->mm_count);
+               tsk->active_mm = mm;
+       }
+       tsk->mm = mm;
+       switch_mm(active_mm, mm, tsk);
+       preempt_enable_rt();
+       task_unlock(tsk);
+#ifdef finish_arch_post_lock_switch
+       finish_arch_post_lock_switch();
+#endif
+
+       if (active_mm != mm)
+               mmdrop(active_mm);
+}
+EXPORT_SYMBOL_GPL(use_mm);
+
+/*
+ * unuse_mm
+ *     Reverses the effect of use_mm, i.e. releases the
+ *     specified mm context which was earlier taken on
+ *     by the calling kernel thread
+ *     (Note: this routine is intended to be called only
+ *     from a kernel thread context)
+ */
+void unuse_mm(struct mm_struct *mm)
+{
+       struct task_struct *tsk = current;
+
+       task_lock(tsk);
+       sync_mm_rss(mm);
+       tsk->mm = NULL;
+       /* active_mm is still 'mm' */
+       enter_lazy_tlb(mm, tsk);
+       task_unlock(tsk);
+}
+EXPORT_SYMBOL_GPL(unuse_mm);