Commit 
41151e77a4 ("powerpc: Hugetlb for BookE") added some
#ifdef CONFIG_MM_SLICES conditionals to hugetlb_get_unmapped_area()
and vma_mmu_pagesize().  Unfortunately this is not the correct config
symbol; it should be CONFIG_PPC_MM_SLICES.  The result is that
attempting to use hugetlbfs on 64-bit Power server processors results
in an infinite stack recursion between get_unmapped_area() and
hugetlb_get_unmapped_area().
This fixes it by changing the #ifdef to use CONFIG_PPC_MM_SLICES
in those functions and also in book3e_hugetlb_preload().
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
 
        if (unlikely(is_kernel_addr(ea)))
                return;
 
-#ifdef CONFIG_MM_SLICES
+#ifdef CONFIG_PPC_MM_SLICES
        psize = mmu_get_tsize(get_slice_psize(mm, ea));
        tsize = mmu_get_psize(psize);
        shift = mmu_psize_defs[psize].shift;
 
                                        unsigned long len, unsigned long pgoff,
                                        unsigned long flags)
 {
-#ifdef CONFIG_MM_SLICES
+#ifdef CONFIG_PPC_MM_SLICES
        struct hstate *hstate = hstate_file(file);
        int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
 
 
 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
 {
-#ifdef CONFIG_MM_SLICES
+#ifdef CONFIG_PPC_MM_SLICES
        unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
 
        return 1UL << mmu_psize_to_shift(psize);