#include <linux/export.h>
#include <linux/bvec.h>
#include <linux/uio.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/splice.h>
#include <net/checksum.h>
#define PIPE_PARANOIA /* for now */
#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
size_t left; \
size_t wanted =