[PATCH] PPC64 mmu_context_init needs to run earlier

Using idr_get_new_above in init_new_context lets us get rid of an
awkward init function which wasn't running early enough in boot
anyway.
Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/mm/init.c

@@ -489,7 +489,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 		return -ENOMEM;
 
 	spin_lock(&mmu_context_lock);
-	err = idr_get_new(&mmu_context_idr, NULL, &index);
+	err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index);
 	spin_unlock(&mmu_context_lock);
 
 	if (err == -EAGAIN)
@@ -518,19 +518,6 @@ void destroy_context(struct mm_struct *mm)
 	hugetlb_mm_free_pgd(mm);
 }
 
-static int __init mmu_context_init(void)
-{
-	int index;
-
-	/* Reserve the first (invalid) context*/
-	idr_pre_get(&mmu_context_idr, GFP_KERNEL);
-	idr_get_new(&mmu_context_idr, NULL, &index);
-	BUG_ON(0 != index);
-
-	return 0;
-}
-arch_initcall(mmu_context_init);
-
 /*
  * Do very early mm setup.
  */