ulong lock_flags = 0;
        ulong lock_flags2 = 0;
 
-       if (tty == NULL)
+       if (!tty)
                return 0;
 
        un = tty->driver_data;
        struct channel_t *ch;
        struct un_t *un;
 
-       if (tty == NULL)
+       if (!tty)
                return bytes_available;
 
        un = tty->driver_data;
 
        brd->serial_ports = kcalloc(brd->nasync, sizeof(*brd->serial_ports),
                                        GFP_KERNEL);
-       if (brd->serial_ports == NULL)
+       if (!brd->serial_ports)
                return -ENOMEM;
 
        brd->printer_ports = kcalloc(brd->nasync, sizeof(*brd->printer_ports),
                                        GFP_KERNEL);
-       if (brd->printer_ports == NULL)
+       if (!brd->printer_ports)
                return -ENOMEM;
 
        for (i = 0; i < brd->nasync; i++) {
                                return -1;
                        }
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                                return -1;
                        }
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                                return -1;
                        }
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p->u.board.v_pcibus = 1;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                                return -1;
                        }
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                                return -1;
                        }
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                case NPORTS:    /* number of ports */
                        if (p->type == BNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                                p->u.board.v_nport = 1;
                        } else if (p->type == CNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                                p->u.conc.v_nport = 1;
                        } else if (p->type == MNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
 
                case ID:        /* letter ID used in tty name */
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                case STARTO:    /* start offset of ID */
                        if (p->type == BNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                                p->u.board.v_start = 1;
                        } else if (p->type == CNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                                p->u.conc.v_start = 1;
                        } else if (p->type == MNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                case LINE:      /* line information */
                        if (dgap_checknode(p))
                                return -1;
-                       if (brd == NULL) {
+                       if (!brd) {
                                dgap_err("must specify board before line info");
                                return -1;
                        }
                case CONC:      /* concentrator information */
                        if (dgap_checknode(p))
                                return -1;
-                       if (line == NULL) {
+                       if (!line) {
                                dgap_err("must specify line info before concentrator");
                                return -1;
                        }
                case MOD:       /* EBI module */
                        if (dgap_checknode(p))
                                return -1;
-                       if (brd == NULL) {
+                       if (!brd) {
                                dgap_err("must specify board info before EBI modules");
                                return -1;
                        }
                                linecnt = 0;
                                break;
                        default:
-                               if (conc == NULL) {
+                               if (!conc) {
                                        dgap_err("must specify concentrator info before EBI module");
                                        return -1;
                                }
                case SPEED:     /* sync line speed indication */
                        if (p->type == LNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                                p->u.line.v_speed = 1;
                        } else if (p->type == CNODE) {
                                s = dgap_getword(in);
-                               if (s == NULL) {
+                               if (!s) {
                                        dgap_err("unexpected end of file");
                                        return -1;
                                }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }
                        }
                        p = p->next;
                        s = dgap_getword(in);
-                       if (s == NULL) {
+                       if (!s) {
                                dgap_err("unexpected end of file");
                                return -1;
                        }