op = &argp->ops[i];
                op->replay = NULL;
 
-               /*
-                * We can't use READ_BUF() here because we need to handle
-                * a missing opcode as an OP_WRITE + 1. So we need to check
-                * to see if we're truly at the end of our buffer or if there
-                * is another page we need to flip to.
-                */
-
-               if (argp->p == argp->end) {
-                       if (argp->pagelen < 4) {
-                               /* There isn't an opcode still on the wire */
-                               op->opnum = OP_WRITE + 1;
-                               op->status = nfserr_bad_xdr;
-                               argp->opcnt = i+1;
-                               break;
-                       }
-
-                       /*
-                        * False alarm. We just hit a page boundary, but there
-                        * is still data available.  Move pointer across page
-                        * boundary.  *snip from READ_BUF*
-                        */
-                       argp->p = page_address(argp->pagelist[0]);
-                       argp->pagelist++;
-                       if (argp->pagelen < PAGE_SIZE) {
-                               argp->end = argp->p + (argp->pagelen>>2);
-                               argp->pagelen = 0;
-                       } else {
-                               argp->end = argp->p + (PAGE_SIZE>>2);
-                               argp->pagelen -= PAGE_SIZE;
-                       }
-               }
-               op->opnum = ntohl(*argp->p++);
+               READ_BUF(4);
+               READ32(op->opnum);
 
                if (op->opnum >= FIRST_NFS4_OP && op->opnum <= LAST_NFS4_OP)
                        op->status = ops->decoders[op->opnum](argp, &op->u);