/* Note: the +2 is for the destination buffers of the ddf/raid6 case where we calculate over all devices (not just the data blocks), using zeros in place of the P and Q blocks.  */
static size_t scribble_len(int num)
/* Note: the +2 is for the destination buffers of the ddf/raid6 case where we calculate over all devices (not just the data blocks), using zeros in place of the P and Q blocks.  */
static size_t scribble_len(int num)
{
	size_t len;
	len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
	return len;
}