pud_req_readwrite
struct pud_req_readwrite *pr_rw;
struct pud_req_readwrite *pr_rw;
struct pud_req_readwrite *pc_rw;
allocsize = sizeof(struct pud_req_readwrite) + bp->b_bcount;
#define pud_creq_read pud_req_readwrite
#define pud_creq_write pud_req_readwrite