arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{
	struct vm_area_struct *vma, *prev;
	struct mm_struct *mm = current->mm;
	unsigned long addr = addr0;
	int do_color_align, last_mmap;
	struct vm_unmapped_area_info info;

#ifdef CONFIG_64BIT
	/* This should only ever run for 32-bit processes.  */
	BUG_ON(!test_thread_flag(TIF_32BIT));
#endif

	/* requested length too big for entire address space */
	if (len > TASK_SIZE)
		return -ENOMEM;

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = 1;
	last_mmap = GET_LAST_MMAP(filp);

	if (flags & MAP_FIXED) {
		if ((flags & MAP_SHARED) && last_mmap &&
		    (addr - shared_align_offset(last_mmap, pgoff))
			& (SHM_COLOUR - 1))
			return -EINVAL;
		goto found_addr;
	}

	/* requesting a specific address */
	if (addr) {
		if (do_color_align && last_mmap)
			addr = COLOR_ALIGN(addr, last_mmap, pgoff);
		else
			addr = PAGE_ALIGN(addr);

		vma = find_vma_prev(mm, addr, &prev);
		if (TASK_SIZE - len >= addr &&
		    (!vma || addr + len <= vm_start_gap(vma)) &&
		    (!prev || addr >= vm_end_gap(prev)))
			goto found_addr;
	}

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	info.length = len;
	info.low_limit = PAGE_SIZE;
	info.high_limit = mm->mmap_base;
	info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
	info.align_offset = shared_align_offset(last_mmap, pgoff);
	addr = vm_unmapped_area(&info);
	if (!(addr & ~PAGE_MASK))
		goto found_addr;
	VM_BUG_ON(addr != -ENOMEM);

	/*
	 * A failed mmap() very likely causes application failure,
	 * so fall back to the bottom-up function here. This scenario
	 * can happen with large stack limits and large mmap()
	 * allocations.
	 */
	return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);

found_addr:
	if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
		SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));

	return addr;
}
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
			  const unsigned long len, const unsigned long pgoff,
			  const unsigned long flags)
{
	struct vm_area_struct *vma, *prev;
	struct mm_struct *mm = current->mm;
	unsigned long addr = addr0;
	int do_color_align, last_mmap;
	struct vm_unmapped_area_info info;

#ifdef CONFIG_64BIT
	 
	BUG_ON(!test_thread_flag(TIF_32BIT));
#endif

	 
	if (len > TASK_SIZE)
		return -ENOMEM;

	do_color_align = 0;
	if (filp || (flags & MAP_SHARED))
		do_color_align = 1;
	last_mmap = GET_LAST_MMAP(filp);

	if (flags & MAP_FIXED) {
		if ((flags & MAP_SHARED) && last_mmap &&
		    (addr - shared_align_offset(last_mmap, pgoff))
			& (SHM_COLOUR - 1))
			return -EINVAL;
		goto found_addr;
	}

	 
	if (addr) {
		if (do_color_align && last_mmap)
			addr = COLOR_ALIGN(addr, last_mmap, pgoff);
		else
			addr = PAGE_ALIGN(addr);

		vma = find_vma_prev(mm, addr, &prev);
		if (TASK_SIZE - len >= addr &&
		    (!vma || addr + len <= vm_start_gap(vma)) &&
		    (!prev || addr >= vm_end_gap(prev)))
			goto found_addr;
	}

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
	info.length = len;
	info.low_limit = PAGE_SIZE;
	info.high_limit = mm->mmap_base;
	info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
	info.align_offset = shared_align_offset(last_mmap, pgoff);
	addr = vm_unmapped_area(&info);
	if (!(addr & ~PAGE_MASK))
		goto found_addr;
	VM_BUG_ON(addr != -ENOMEM);

	 
	return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);

found_addr:
	if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
		SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));

	return addr;
}