]> Pileus Git - ~andy/linux/blobdiff - drivers/tty/n_tty.c
tty: add missing newlines to WARN_RATELIMIT
[~andy/linux] / drivers / tty / n_tty.c
index 8c0b7b42319c44d7038892d0026582797acad95a..19083efa2314660b25e0fb5bc793af6fb7e9af57 100644 (file)
 #define ECHO_OP_SET_CANON_COL 0x81
 #define ECHO_OP_ERASE_TAB 0x82
 
+struct n_tty_data {
+       unsigned int column;
+       unsigned long overrun_time;
+       int num_overrun;
+
+       unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
+       unsigned char echo_overrun:1;
+
+       DECLARE_BITMAP(process_char_map, 256);
+       DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
+
+       char *read_buf;
+       int read_head;
+       int read_tail;
+       int read_cnt;
+
+       unsigned char *echo_buf;
+       unsigned int echo_pos;
+       unsigned int echo_cnt;
+
+       int canon_data;
+       unsigned long canon_head;
+       unsigned int canon_column;
+
+       struct mutex atomic_read_lock;
+       struct mutex output_lock;
+       struct mutex echo_lock;
+       spinlock_t read_lock;
+};
+
 static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
                               unsigned char __user *ptr)
 {
-       tty_audit_add_data(tty, &x, 1);
+       struct n_tty_data *ldata = tty->disc_data;
+
+       tty_audit_add_data(tty, &x, 1, ldata->icanon);
        return put_user(x, ptr);
 }
 
@@ -92,17 +124,18 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
 
 static void n_tty_set_room(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int left;
        int old_left;
 
-       /* tty->read_cnt is not read locked ? */
+       /* ldata->read_cnt is not read locked ? */
        if (I_PARMRK(tty)) {
                /* Multiply read_cnt by 3, since each byte might take up to
                 * three times as many spaces when PARMRK is set (depending on
                 * its flags, e.g. parity error). */
-               left = N_TTY_BUF_SIZE - tty->read_cnt * 3 - 1;
+               left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1;
        } else
-               left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+               left = N_TTY_BUF_SIZE - ldata->read_cnt - 1;
 
        /*
         * If we are doing input canonicalization, and there are no
@@ -111,44 +144,47 @@ static void n_tty_set_room(struct tty_struct *tty)
         * characters will be beeped.
         */
        if (left <= 0)
-               left = tty->icanon && !tty->canon_data;
+               left = ldata->icanon && !ldata->canon_data;
        old_left = tty->receive_room;
        tty->receive_room = left;
 
        /* Did this open up the receive buffer? We may need to flip */
-       if (left && !old_left)
-               schedule_work(&tty->buf.work);
+       if (left && !old_left) {
+               WARN_RATELIMIT(tty->port->itty == NULL,
+                               "scheduling with invalid itty\n");
+               schedule_work(&tty->port->buf.work);
+       }
 }
 
-static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
+static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata)
 {
-       if (tty->read_cnt < N_TTY_BUF_SIZE) {
-               tty->read_buf[tty->read_head] = c;
-               tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
-               tty->read_cnt++;
+       if (ldata->read_cnt < N_TTY_BUF_SIZE) {
+               ldata->read_buf[ldata->read_head] = c;
+               ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1);
+               ldata->read_cnt++;
        }
 }
 
 /**
  *     put_tty_queue           -       add character to tty
  *     @c: character
- *     @tty: tty device
+ *     @ldata: n_tty data
  *
  *     Add a character to the tty read_buf queue. This is done under the
  *     read_lock to serialize character addition and also to protect us
  *     against parallel reads or flushes
  */
 
-static void put_tty_queue(unsigned char c, struct tty_struct *tty)
+static void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
 {
        unsigned long flags;
        /*
         *      The problem of stomping on the buffers ends here.
         *      Why didn't anyone see this one coming? --AJK
        */
-       spin_lock_irqsave(&tty->read_lock, flags);
-       put_tty_queue_nolock(c, tty);
-       spin_unlock_irqrestore(&tty->read_lock, flags);
+       spin_lock_irqsave(&ldata->read_lock, flags);
+       put_tty_queue_nolock(c, ldata);
+       spin_unlock_irqrestore(&ldata->read_lock, flags);
 }
 
 /**
@@ -179,18 +215,19 @@ static void check_unthrottle(struct tty_struct *tty)
 
 static void reset_buffer_flags(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        unsigned long flags;
 
-       spin_lock_irqsave(&tty->read_lock, flags);
-       tty->read_head = tty->read_tail = tty->read_cnt = 0;
-       spin_unlock_irqrestore(&tty->read_lock, flags);
+       spin_lock_irqsave(&ldata->read_lock, flags);
+       ldata->read_head = ldata->read_tail = ldata->read_cnt = 0;
+       spin_unlock_irqrestore(&ldata->read_lock, flags);
 
-       mutex_lock(&tty->echo_lock);
-       tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0;
-       mutex_unlock(&tty->echo_lock);
+       mutex_lock(&ldata->echo_lock);
+       ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0;
+       mutex_unlock(&ldata->echo_lock);
 
-       tty->canon_head = tty->canon_data = tty->erasing = 0;
-       memset(&tty->read_flags, 0, sizeof tty->read_flags);
+       ldata->canon_head = ldata->canon_data = ldata->erasing = 0;
+       bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
        n_tty_set_room(tty);
 }
 
@@ -235,18 +272,19 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
 
 static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        unsigned long flags;
        ssize_t n = 0;
 
-       spin_lock_irqsave(&tty->read_lock, flags);
-       if (!tty->icanon) {
-               n = tty->read_cnt;
-       } else if (tty->canon_data) {
-               n = (tty->canon_head > tty->read_tail) ?
-                       tty->canon_head - tty->read_tail :
-                       tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail);
+       spin_lock_irqsave(&ldata->read_lock, flags);
+       if (!ldata->icanon) {
+               n = ldata->read_cnt;
+       } else if (ldata->canon_data) {
+               n = (ldata->canon_head > ldata->read_tail) ?
+                       ldata->canon_head - ldata->read_tail :
+                       ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail);
        }
-       spin_unlock_irqrestore(&tty->read_lock, flags);
+       spin_unlock_irqrestore(&ldata->read_lock, flags);
        return n;
 }
 
@@ -301,6 +339,7 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
 
 static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int     spaces;
 
        if (!space)
@@ -309,48 +348,48 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
        switch (c) {
        case '\n':
                if (O_ONLRET(tty))
-                       tty->column = 0;
+                       ldata->column = 0;
                if (O_ONLCR(tty)) {
                        if (space < 2)
                                return -1;
-                       tty->canon_column = tty->column = 0;
+                       ldata->canon_column = ldata->column = 0;
                        tty->ops->write(tty, "\r\n", 2);
                        return 2;
                }
-               tty->canon_column = tty->column;
+               ldata->canon_column = ldata->column;
                break;
        case '\r':
-               if (O_ONOCR(tty) && tty->column == 0)
+               if (O_ONOCR(tty) && ldata->column == 0)
                        return 0;
                if (O_OCRNL(tty)) {
                        c = '\n';
                        if (O_ONLRET(tty))
-                               tty->canon_column = tty->column = 0;
+                               ldata->canon_column = ldata->column = 0;
                        break;
                }
-               tty->canon_column = tty->column = 0;
+               ldata->canon_column = ldata->column = 0;
                break;
        case '\t':
-               spaces = 8 - (tty->column & 7);
+               spaces = 8 - (ldata->column & 7);
                if (O_TABDLY(tty) == XTABS) {
                        if (space < spaces)
                                return -1;
-                       tty->column += spaces;
+                       ldata->column += spaces;
                        tty->ops->write(tty, "        ", spaces);
                        return spaces;
                }
-               tty->column += spaces;
+               ldata->column += spaces;
                break;
        case '\b':
-               if (tty->column > 0)
-                       tty->column--;
+               if (ldata->column > 0)
+                       ldata->column--;
                break;
        default:
                if (!iscntrl(c)) {
                        if (O_OLCUC(tty))
                                c = toupper(c);
                        if (!is_continuation(c, tty))
-                               tty->column++;
+                               ldata->column++;
                }
                break;
        }
@@ -375,14 +414,15 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
 
 static int process_output(unsigned char c, struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int     space, retval;
 
-       mutex_lock(&tty->output_lock);
+       mutex_lock(&ldata->output_lock);
 
        space = tty_write_room(tty);
        retval = do_output_char(c, tty, space);
 
-       mutex_unlock(&tty->output_lock);
+       mutex_unlock(&ldata->output_lock);
        if (retval < 0)
                return -1;
        else
@@ -411,15 +451,16 @@ static int process_output(unsigned char c, struct tty_struct *tty)
 static ssize_t process_output_block(struct tty_struct *tty,
                                    const unsigned char *buf, unsigned int nr)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int     space;
        int     i;
        const unsigned char *cp;
 
-       mutex_lock(&tty->output_lock);
+       mutex_lock(&ldata->output_lock);
 
        space = tty_write_room(tty);
        if (!space) {
-               mutex_unlock(&tty->output_lock);
+               mutex_unlock(&ldata->output_lock);
                return 0;
        }
        if (nr > space)
@@ -431,30 +472,30 @@ static ssize_t process_output_block(struct tty_struct *tty,
                switch (c) {
                case '\n':
                        if (O_ONLRET(tty))
-                               tty->column = 0;
+                               ldata->column = 0;
                        if (O_ONLCR(tty))
                                goto break_out;
-                       tty->canon_column = tty->column;
+                       ldata->canon_column = ldata->column;
                        break;
                case '\r':
-                       if (O_ONOCR(tty) && tty->column == 0)
+                       if (O_ONOCR(tty) && ldata->column == 0)
                                goto break_out;
                        if (O_OCRNL(tty))
                                goto break_out;
-                       tty->canon_column = tty->column = 0;
+                       ldata->canon_column = ldata->column = 0;
                        break;
                case '\t':
                        goto break_out;
                case '\b':
-                       if (tty->column > 0)
-                               tty->column--;
+                       if (ldata->column > 0)
+                               ldata->column--;
                        break;
                default:
                        if (!iscntrl(c)) {
                                if (O_OLCUC(tty))
                                        goto break_out;
                                if (!is_continuation(c, tty))
-                                       tty->column++;
+                                       ldata->column++;
                        }
                        break;
                }
@@ -462,7 +503,7 @@ static ssize_t process_output_block(struct tty_struct *tty,
 break_out:
        i = tty->ops->write(tty, buf, i);
 
-       mutex_unlock(&tty->output_lock);
+       mutex_unlock(&ldata->output_lock);
        return i;
 }
 
@@ -494,21 +535,22 @@ break_out:
 
 static void process_echoes(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int     space, nr;
        unsigned char c;
        unsigned char *cp, *buf_end;
 
-       if (!tty->echo_cnt)
+       if (!ldata->echo_cnt)
                return;
 
-       mutex_lock(&tty->output_lock);
-       mutex_lock(&tty->echo_lock);
+       mutex_lock(&ldata->output_lock);
+       mutex_lock(&ldata->echo_lock);
 
        space = tty_write_room(tty);
 
-       buf_end = tty->echo_buf + N_TTY_BUF_SIZE;
-       cp = tty->echo_buf + tty->echo_pos;
-       nr = tty->echo_cnt;
+       buf_end = ldata->echo_buf + N_TTY_BUF_SIZE;
+       cp = ldata->echo_buf + ldata->echo_pos;
+       nr = ldata->echo_cnt;
        while (nr > 0) {
                c = *cp;
                if (c == ECHO_OP_START) {
@@ -545,7 +587,7 @@ static void process_echoes(struct tty_struct *tty)
                                 * Otherwise, tab spacing is normal.
                                 */
                                if (!(num_chars & 0x80))
-                                       num_chars += tty->canon_column;
+                                       num_chars += ldata->canon_column;
                                num_bs = 8 - (num_chars & 7);
 
                                if (num_bs > space) {
@@ -555,22 +597,22 @@ static void process_echoes(struct tty_struct *tty)
                                space -= num_bs;
                                while (num_bs--) {
                                        tty_put_char(tty, '\b');
-                                       if (tty->column > 0)
-                                               tty->column--;
+                                       if (ldata->column > 0)
+                                               ldata->column--;
                                }
                                cp += 3;
                                nr -= 3;
                                break;
 
                        case ECHO_OP_SET_CANON_COL:
-                               tty->canon_column = tty->column;
+                               ldata->canon_column = ldata->column;
                                cp += 2;
                                nr -= 2;
                                break;
 
                        case ECHO_OP_MOVE_BACK_COL:
-                               if (tty->column > 0)
-                                       tty->column--;
+                               if (ldata->column > 0)
+                                       ldata->column--;
                                cp += 2;
                                nr -= 2;
                                break;
@@ -582,7 +624,7 @@ static void process_echoes(struct tty_struct *tty)
                                        break;
                                }
                                tty_put_char(tty, ECHO_OP_START);
-                               tty->column++;
+                               ldata->column++;
                                space--;
                                cp += 2;
                                nr -= 2;
@@ -604,7 +646,7 @@ static void process_echoes(struct tty_struct *tty)
                                }
                                tty_put_char(tty, '^');
                                tty_put_char(tty, op ^ 0100);
-                               tty->column += 2;
+                               ldata->column += 2;
                                space -= 2;
                                cp += 2;
                                nr -= 2;
@@ -635,20 +677,20 @@ static void process_echoes(struct tty_struct *tty)
        }
 
        if (nr == 0) {
-               tty->echo_pos = 0;
-               tty->echo_cnt = 0;
-               tty->echo_overrun = 0;
+               ldata->echo_pos = 0;
+               ldata->echo_cnt = 0;
+               ldata->echo_overrun = 0;
        } else {
-               int num_processed = tty->echo_cnt - nr;
-               tty->echo_pos += num_processed;
-               tty->echo_pos &= N_TTY_BUF_SIZE - 1;
-               tty->echo_cnt = nr;
+               int num_processed = ldata->echo_cnt - nr;
+               ldata->echo_pos += num_processed;
+               ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
+               ldata->echo_cnt = nr;
                if (num_processed > 0)
-                       tty->echo_overrun = 0;
+                       ldata->echo_overrun = 0;
        }
 
-       mutex_unlock(&tty->echo_lock);
-       mutex_unlock(&tty->output_lock);
+       mutex_unlock(&ldata->echo_lock);
+       mutex_unlock(&ldata->output_lock);
 
        if (tty->ops->flush_chars)
                tty->ops->flush_chars(tty);
@@ -657,72 +699,70 @@ static void process_echoes(struct tty_struct *tty)
 /**
  *     add_echo_byte   -       add a byte to the echo buffer
  *     @c: unicode byte to echo
- *     @tty: terminal device
+ *     @ldata: n_tty data
  *
  *     Add a character or operation byte to the echo buffer.
  *
  *     Should be called under the echo lock to protect the echo buffer.
  */
 
-static void add_echo_byte(unsigned char c, struct tty_struct *tty)
+static void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
 {
        int     new_byte_pos;
 
-       if (tty->echo_cnt == N_TTY_BUF_SIZE) {
+       if (ldata->echo_cnt == N_TTY_BUF_SIZE) {
                /* Circular buffer is already at capacity */
-               new_byte_pos = tty->echo_pos;
+               new_byte_pos = ldata->echo_pos;
 
                /*
                 * Since the buffer start position needs to be advanced,
                 * be sure to step by a whole operation byte group.
                 */
-               if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) {
-                       if (tty->echo_buf[(tty->echo_pos + 1) &
+               if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) {
+                       if (ldata->echo_buf[(ldata->echo_pos + 1) &
                                          (N_TTY_BUF_SIZE - 1)] ==
                                                ECHO_OP_ERASE_TAB) {
-                               tty->echo_pos += 3;
-                               tty->echo_cnt -= 2;
+                               ldata->echo_pos += 3;
+                               ldata->echo_cnt -= 2;
                        } else {
-                               tty->echo_pos += 2;
-                               tty->echo_cnt -= 1;
+                               ldata->echo_pos += 2;
+                               ldata->echo_cnt -= 1;
                        }
                } else {
-                       tty->echo_pos++;
+                       ldata->echo_pos++;
                }
-               tty->echo_pos &= N_TTY_BUF_SIZE - 1;
+               ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
 
-               tty->echo_overrun = 1;
+               ldata->echo_overrun = 1;
        } else {
-               new_byte_pos = tty->echo_pos + tty->echo_cnt;
+               new_byte_pos = ldata->echo_pos + ldata->echo_cnt;
                new_byte_pos &= N_TTY_BUF_SIZE - 1;
-               tty->echo_cnt++;
+               ldata->echo_cnt++;
        }
 
-       tty->echo_buf[new_byte_pos] = c;
+       ldata->echo_buf[new_byte_pos] = c;
 }
 
 /**
  *     echo_move_back_col      -       add operation to move back a column
- *     @tty: terminal device
+ *     @ldata: n_tty data
  *
  *     Add an operation to the echo buffer to move back one column.
  *
  *     Locking: echo_lock to protect the echo buffer
  */
 
-static void echo_move_back_col(struct tty_struct *tty)
+static void echo_move_back_col(struct n_tty_data *ldata)
 {
-       mutex_lock(&tty->echo_lock);
-
-       add_echo_byte(ECHO_OP_START, tty);
-       add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty);
-
-       mutex_unlock(&tty->echo_lock);
+       mutex_lock(&ldata->echo_lock);
+       add_echo_byte(ECHO_OP_START, ldata);
+       add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
+       mutex_unlock(&ldata->echo_lock);
 }
 
 /**
  *     echo_set_canon_col      -       add operation to set the canon column
- *     @tty: terminal device
+ *     @ldata: n_tty data
  *
  *     Add an operation to the echo buffer to set the canon column
  *     to the current column.
@@ -730,21 +770,19 @@ static void echo_move_back_col(struct tty_struct *tty)
  *     Locking: echo_lock to protect the echo buffer
  */
 
-static void echo_set_canon_col(struct tty_struct *tty)
+static void echo_set_canon_col(struct n_tty_data *ldata)
 {
-       mutex_lock(&tty->echo_lock);
-
-       add_echo_byte(ECHO_OP_START, tty);
-       add_echo_byte(ECHO_OP_SET_CANON_COL, tty);
-
-       mutex_unlock(&tty->echo_lock);
+       mutex_lock(&ldata->echo_lock);
+       add_echo_byte(ECHO_OP_START, ldata);
+       add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
+       mutex_unlock(&ldata->echo_lock);
 }
 
 /**
  *     echo_erase_tab  -       add operation to erase a tab
  *     @num_chars: number of character columns already used
  *     @after_tab: true if num_chars starts after a previous tab
- *     @tty: terminal device
+ *     @ldata: n_tty data
  *
  *     Add an operation to the echo buffer to erase a tab.
  *
@@ -758,12 +796,12 @@ static void echo_set_canon_col(struct tty_struct *tty)
  */
 
 static void echo_erase_tab(unsigned int num_chars, int after_tab,
-                          struct tty_struct *tty)
+                          struct n_tty_data *ldata)
 {
-       mutex_lock(&tty->echo_lock);
+       mutex_lock(&ldata->echo_lock);
 
-       add_echo_byte(ECHO_OP_START, tty);
-       add_echo_byte(ECHO_OP_ERASE_TAB, tty);
+       add_echo_byte(ECHO_OP_START, ldata);
+       add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
 
        /* We only need to know this modulo 8 (tab spacing) */
        num_chars &= 7;
@@ -772,9 +810,9 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
        if (after_tab)
                num_chars |= 0x80;
 
-       add_echo_byte(num_chars, tty);
+       add_echo_byte(num_chars, ldata);
 
-       mutex_unlock(&tty->echo_lock);
+       mutex_unlock(&ldata->echo_lock);
 }
 
 /**
@@ -790,18 +828,16 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
  *     Locking: echo_lock to protect the echo buffer
  */
 
-static void echo_char_raw(unsigned char c, struct tty_struct *tty)
+static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
 {
-       mutex_lock(&tty->echo_lock);
-
+       mutex_lock(&ldata->echo_lock);
        if (c == ECHO_OP_START) {
-               add_echo_byte(ECHO_OP_START, tty);
-               add_echo_byte(ECHO_OP_START, tty);
+               add_echo_byte(ECHO_OP_START, ldata);
+               add_echo_byte(ECHO_OP_START, ldata);
        } else {
-               add_echo_byte(c, tty);
+               add_echo_byte(c, ldata);
        }
-
-       mutex_unlock(&tty->echo_lock);
+       mutex_unlock(&ldata->echo_lock);
 }
 
 /**
@@ -820,30 +856,32 @@ static void echo_char_raw(unsigned char c, struct tty_struct *tty)
 
 static void echo_char(unsigned char c, struct tty_struct *tty)
 {
-       mutex_lock(&tty->echo_lock);
+       struct n_tty_data *ldata = tty->disc_data;
+
+       mutex_lock(&ldata->echo_lock);
 
        if (c == ECHO_OP_START) {
-               add_echo_byte(ECHO_OP_START, tty);
-               add_echo_byte(ECHO_OP_START, tty);
+               add_echo_byte(ECHO_OP_START, ldata);
+               add_echo_byte(ECHO_OP_START, ldata);
        } else {
                if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
-                       add_echo_byte(ECHO_OP_START, tty);
-               add_echo_byte(c, tty);
+                       add_echo_byte(ECHO_OP_START, ldata);
+               add_echo_byte(c, ldata);
        }
 
-       mutex_unlock(&tty->echo_lock);
+       mutex_unlock(&ldata->echo_lock);
 }
 
 /**
  *     finish_erasing          -       complete erase
- *     @tty: tty doing the erase
+ *     @ldata: n_tty data
  */
 
-static inline void finish_erasing(struct tty_struct *tty)
+static inline void finish_erasing(struct n_tty_data *ldata)
 {
-       if (tty->erasing) {
-               echo_char_raw('/', tty);
-               tty->erasing = 0;
+       if (ldata->erasing) {
+               echo_char_raw('/', ldata);
+               ldata->erasing = 0;
        }
 }
 
@@ -861,12 +899,13 @@ static inline void finish_erasing(struct tty_struct *tty)
 
 static void eraser(unsigned char c, struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        enum { ERASE, WERASE, KILL } kill_type;
        int head, seen_alnums, cnt;
        unsigned long flags;
 
        /* FIXME: locking needed ? */
-       if (tty->read_head == tty->canon_head) {
+       if (ldata->read_head == ldata->canon_head) {
                /* process_output('\a', tty); */ /* what do you think? */
                return;
        }
@@ -876,24 +915,24 @@ static void eraser(unsigned char c, struct tty_struct *tty)
                kill_type = WERASE;
        else {
                if (!L_ECHO(tty)) {
-                       spin_lock_irqsave(&tty->read_lock, flags);
-                       tty->read_cnt -= ((tty->read_head - tty->canon_head) &
+                       spin_lock_irqsave(&ldata->read_lock, flags);
+                       ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
                                          (N_TTY_BUF_SIZE - 1));
-                       tty->read_head = tty->canon_head;
-                       spin_unlock_irqrestore(&tty->read_lock, flags);
+                       ldata->read_head = ldata->canon_head;
+                       spin_unlock_irqrestore(&ldata->read_lock, flags);
                        return;
                }
                if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
-                       spin_lock_irqsave(&tty->read_lock, flags);
-                       tty->read_cnt -= ((tty->read_head - tty->canon_head) &
+                       spin_lock_irqsave(&ldata->read_lock, flags);
+                       ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
                                          (N_TTY_BUF_SIZE - 1));
-                       tty->read_head = tty->canon_head;
-                       spin_unlock_irqrestore(&tty->read_lock, flags);
-                       finish_erasing(tty);
+                       ldata->read_head = ldata->canon_head;
+                       spin_unlock_irqrestore(&ldata->read_lock, flags);
+                       finish_erasing(ldata);
                        echo_char(KILL_CHAR(tty), tty);
                        /* Add a newline if ECHOK is on and ECHOKE is off. */
                        if (L_ECHOK(tty))
-                               echo_char_raw('\n', tty);
+                               echo_char_raw('\n', ldata);
                        return;
                }
                kill_type = KILL;
@@ -901,14 +940,14 @@ static void eraser(unsigned char c, struct tty_struct *tty)
 
        seen_alnums = 0;
        /* FIXME: Locking ?? */
-       while (tty->read_head != tty->canon_head) {
-               head = tty->read_head;
+       while (ldata->read_head != ldata->canon_head) {
+               head = ldata->read_head;
 
                /* erase a single possibly multibyte character */
                do {
                        head = (head - 1) & (N_TTY_BUF_SIZE-1);
-                       c = tty->read_buf[head];
-               } while (is_continuation(c, tty) && head != tty->canon_head);
+                       c = ldata->read_buf[head];
+               } while (is_continuation(c, tty) && head != ldata->canon_head);
 
                /* do not partially erase */
                if (is_continuation(c, tty))
@@ -921,30 +960,31 @@ static void eraser(unsigned char c, struct tty_struct *tty)
                        else if (seen_alnums)
                                break;
                }
-               cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
-               spin_lock_irqsave(&tty->read_lock, flags);
-               tty->read_head = head;
-               tty->read_cnt -= cnt;
-               spin_unlock_irqrestore(&tty->read_lock, flags);
+               cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1);
+               spin_lock_irqsave(&ldata->read_lock, flags);
+               ldata->read_head = head;
+               ldata->read_cnt -= cnt;
+               spin_unlock_irqrestore(&ldata->read_lock, flags);
                if (L_ECHO(tty)) {
                        if (L_ECHOPRT(tty)) {
-                               if (!tty->erasing) {
-                                       echo_char_raw('\\', tty);
-                                       tty->erasing = 1;
+                               if (!ldata->erasing) {
+                                       echo_char_raw('\\', ldata);
+                                       ldata->erasing = 1;
                                }
                                /* if cnt > 1, output a multi-byte character */
                                echo_char(c, tty);
                                while (--cnt > 0) {
                                        head = (head+1) & (N_TTY_BUF_SIZE-1);
-                                       echo_char_raw(tty->read_buf[head], tty);
-                                       echo_move_back_col(tty);
+                                       echo_char_raw(ldata->read_buf[head],
+                                                       ldata);
+                                       echo_move_back_col(ldata);
                                }
                        } else if (kill_type == ERASE && !L_ECHOE(tty)) {
                                echo_char(ERASE_CHAR(tty), tty);
                        } else if (c == '\t') {
                                unsigned int num_chars = 0;
                                int after_tab = 0;
-                               unsigned long tail = tty->read_head;
+                               unsigned long tail = ldata->read_head;
 
                                /*
                                 * Count the columns used for characters
@@ -953,9 +993,9 @@ static void eraser(unsigned char c, struct tty_struct *tty)
                                 * This info is used to go back the correct
                                 * number of columns.
                                 */
-                               while (tail != tty->canon_head) {
+                               while (tail != ldata->canon_head) {
                                        tail = (tail-1) & (N_TTY_BUF_SIZE-1);
-                                       c = tty->read_buf[tail];
+                                       c = ldata->read_buf[tail];
                                        if (c == '\t') {
                                                after_tab = 1;
                                                break;
@@ -966,25 +1006,25 @@ static void eraser(unsigned char c, struct tty_struct *tty)
                                                num_chars++;
                                        }
                                }
-                               echo_erase_tab(num_chars, after_tab, tty);
+                               echo_erase_tab(num_chars, after_tab, ldata);
                        } else {
                                if (iscntrl(c) && L_ECHOCTL(tty)) {
-                                       echo_char_raw('\b', tty);
-                                       echo_char_raw(' ', tty);
-                                       echo_char_raw('\b', tty);
+                                       echo_char_raw('\b', ldata);
+                                       echo_char_raw(' ', ldata);
+                                       echo_char_raw('\b', ldata);
                                }
                                if (!iscntrl(c) || L_ECHOCTL(tty)) {
-                                       echo_char_raw('\b', tty);
-                                       echo_char_raw(' ', tty);
-                                       echo_char_raw('\b', tty);
+                                       echo_char_raw('\b', ldata);
+                                       echo_char_raw(' ', ldata);
+                                       echo_char_raw('\b', ldata);
                                }
                        }
                }
                if (kill_type == ERASE)
                        break;
        }
-       if (tty->read_head == tty->canon_head && L_ECHO(tty))
-               finish_erasing(tty);
+       if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
+               finish_erasing(ldata);
 }
 
 /**
@@ -1023,6 +1063,8 @@ static inline void isig(int sig, struct tty_struct *tty, int flush)
 
 static inline void n_tty_receive_break(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
+
        if (I_IGNBRK(tty))
                return;
        if (I_BRKINT(tty)) {
@@ -1030,10 +1072,10 @@ static inline void n_tty_receive_break(struct tty_struct *tty)
                return;
        }
        if (I_PARMRK(tty)) {
-               put_tty_queue('\377', tty);
-               put_tty_queue('\0', tty);
+               put_tty_queue('\377', ldata);
+               put_tty_queue('\0', ldata);
        }
-       put_tty_queue('\0', tty);
+       put_tty_queue('\0', ldata);
        wake_up_interruptible(&tty->read_wait);
 }
 
@@ -1052,16 +1094,17 @@ static inline void n_tty_receive_break(struct tty_struct *tty)
 
 static inline void n_tty_receive_overrun(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        char buf[64];
 
-       tty->num_overrun++;
-       if (time_before(tty->overrun_time, jiffies - HZ) ||
-                       time_after(tty->overrun_time, jiffies)) {
+       ldata->num_overrun++;
+       if (time_after(jiffies, ldata->overrun_time + HZ) ||
+                       time_after(ldata->overrun_time, jiffies)) {
                printk(KERN_WARNING "%s: %d input overrun(s)\n",
                        tty_name(tty, buf),
-                       tty->num_overrun);
-               tty->overrun_time = jiffies;
-               tty->num_overrun = 0;
+                       ldata->num_overrun);
+               ldata->overrun_time = jiffies;
+               ldata->num_overrun = 0;
        }
 }
 
@@ -1076,16 +1119,18 @@ static inline void n_tty_receive_overrun(struct tty_struct *tty)
 static inline void n_tty_receive_parity_error(struct tty_struct *tty,
                                              unsigned char c)
 {
+       struct n_tty_data *ldata = tty->disc_data;
+
        if (I_IGNPAR(tty))
                return;
        if (I_PARMRK(tty)) {
-               put_tty_queue('\377', tty);
-               put_tty_queue('\0', tty);
-               put_tty_queue(c, tty);
+               put_tty_queue('\377', ldata);
+               put_tty_queue('\0', ldata);
+               put_tty_queue(c, ldata);
        } else  if (I_INPCK(tty))
-               put_tty_queue('\0', tty);
+               put_tty_queue('\0', ldata);
        else
-               put_tty_queue(c, tty);
+               put_tty_queue(c, ldata);
        wake_up_interruptible(&tty->read_wait);
 }
 
@@ -1101,11 +1146,12 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty,
 
 static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        unsigned long flags;
        int parmrk;
 
-       if (tty->raw) {
-               put_tty_queue(c, tty);
+       if (ldata->raw) {
+               put_tty_queue(c, ldata);
                return;
        }
 
@@ -1115,7 +1161,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
                c = tolower(c);
 
        if (L_EXTPROC(tty)) {
-               put_tty_queue(c, tty);
+               put_tty_queue(c, ldata);
                return;
        }
 
@@ -1143,26 +1189,26 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
         * handle specially, do shortcut processing to speed things
         * up.
         */
-       if (!test_bit(c, tty->process_char_map) || tty->lnext) {
-               tty->lnext = 0;
+       if (!test_bit(c, ldata->process_char_map) || ldata->lnext) {
+               ldata->lnext = 0;
                parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
-               if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
+               if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
                        /* beep if no space */
                        if (L_ECHO(tty))
                                process_output('\a', tty);
                        return;
                }
                if (L_ECHO(tty)) {
-                       finish_erasing(tty);
+                       finish_erasing(ldata);
                        /* Record the column of first canon char. */
-                       if (tty->canon_head == tty->read_head)
-                               echo_set_canon_col(tty);
+                       if (ldata->canon_head == ldata->read_head)
+                               echo_set_canon_col(ldata);
                        echo_char(c, tty);
                        process_echoes(tty);
                }
                if (parmrk)
-                       put_tty_queue(c, tty);
-               put_tty_queue(c, tty);
+                       put_tty_queue(c, ldata);
+               put_tty_queue(c, ldata);
                return;
        }
 
@@ -1218,7 +1264,7 @@ send_signal:
        } else if (c == '\n' && I_INLCR(tty))
                c = '\r';
 
-       if (tty->icanon) {
+       if (ldata->icanon) {
                if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
                    (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
                        eraser(c, tty);
@@ -1226,12 +1272,12 @@ send_signal:
                        return;
                }
                if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
-                       tty->lnext = 1;
+                       ldata->lnext = 1;
                        if (L_ECHO(tty)) {
-                               finish_erasing(tty);
+                               finish_erasing(ldata);
                                if (L_ECHOCTL(tty)) {
-                                       echo_char_raw('^', tty);
-                                       echo_char_raw('\b', tty);
+                                       echo_char_raw('^', ldata);
+                                       echo_char_raw('\b', ldata);
                                        process_echoes(tty);
                                }
                        }
@@ -1239,34 +1285,34 @@ send_signal:
                }
                if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
                    L_IEXTEN(tty)) {
-                       unsigned long tail = tty->canon_head;
+                       unsigned long tail = ldata->canon_head;
 
-                       finish_erasing(tty);
+                       finish_erasing(ldata);
                        echo_char(c, tty);
-                       echo_char_raw('\n', tty);
-                       while (tail != tty->read_head) {
-                               echo_char(tty->read_buf[tail], tty);
+                       echo_char_raw('\n', ldata);
+                       while (tail != ldata->read_head) {
+                               echo_char(ldata->read_buf[tail], tty);
                                tail = (tail+1) & (N_TTY_BUF_SIZE-1);
                        }
                        process_echoes(tty);
                        return;
                }
                if (c == '\n') {
-                       if (tty->read_cnt >= N_TTY_BUF_SIZE) {
+                       if (ldata->read_cnt >= N_TTY_BUF_SIZE) {
                                if (L_ECHO(tty))
                                        process_output('\a', tty);
                                return;
                        }
                        if (L_ECHO(tty) || L_ECHONL(tty)) {
-                               echo_char_raw('\n', tty);
+                               echo_char_raw('\n', ldata);
                                process_echoes(tty);
                        }
                        goto handle_newline;
                }
                if (c == EOF_CHAR(tty)) {
-                       if (tty->read_cnt >= N_TTY_BUF_SIZE)
+                       if (ldata->read_cnt >= N_TTY_BUF_SIZE)
                                return;
-                       if (tty->canon_head != tty->read_head)
+                       if (ldata->canon_head != ldata->read_head)
                                set_bit(TTY_PUSH, &tty->flags);
                        c = __DISABLED_CHAR;
                        goto handle_newline;
@@ -1275,7 +1321,7 @@ send_signal:
                    (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
                        parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
                                 ? 1 : 0;
-                       if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
+                       if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
                                if (L_ECHO(tty))
                                        process_output('\a', tty);
                                return;
@@ -1285,8 +1331,8 @@ send_signal:
                         */
                        if (L_ECHO(tty)) {
                                /* Record the column of first canon char. */
-                               if (tty->canon_head == tty->read_head)
-                                       echo_set_canon_col(tty);
+                               if (ldata->canon_head == ldata->read_head)
+                                       echo_set_canon_col(ldata);
                                echo_char(c, tty);
                                process_echoes(tty);
                        }
@@ -1295,15 +1341,15 @@ send_signal:
                         * EOL_CHAR and EOL2_CHAR?
                         */
                        if (parmrk)
-                               put_tty_queue(c, tty);
+                               put_tty_queue(c, ldata);
 
 handle_newline:
-                       spin_lock_irqsave(&tty->read_lock, flags);
-                       set_bit(tty->read_head, tty->read_flags);
-                       put_tty_queue_nolock(c, tty);
-                       tty->canon_head = tty->read_head;
-                       tty->canon_data++;
-                       spin_unlock_irqrestore(&tty->read_lock, flags);
+                       spin_lock_irqsave(&ldata->read_lock, flags);
+                       set_bit(ldata->read_head, ldata->read_flags);
+                       put_tty_queue_nolock(c, ldata);
+                       ldata->canon_head = ldata->read_head;
+                       ldata->canon_data++;
+                       spin_unlock_irqrestore(&ldata->read_lock, flags);
                        kill_fasync(&tty->fasync, SIGIO, POLL_IN);
                        if (waitqueue_active(&tty->read_wait))
                                wake_up_interruptible(&tty->read_wait);
@@ -1312,29 +1358,29 @@ handle_newline:
        }
 
        parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
-       if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
+       if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
                /* beep if no space */
                if (L_ECHO(tty))
                        process_output('\a', tty);
                return;
        }
        if (L_ECHO(tty)) {
-               finish_erasing(tty);
+               finish_erasing(ldata);
                if (c == '\n')
-                       echo_char_raw('\n', tty);
+                       echo_char_raw('\n', ldata);
                else {
                        /* Record the column of first canon char. */
-                       if (tty->canon_head == tty->read_head)
-                               echo_set_canon_col(tty);
+                       if (ldata->canon_head == ldata->read_head)
+                               echo_set_canon_col(ldata);
                        echo_char(c, tty);
                }
                process_echoes(tty);
        }
 
        if (parmrk)
-               put_tty_queue(c, tty);
+               put_tty_queue(c, ldata);
 
-       put_tty_queue(c, tty);
+       put_tty_queue(c, ldata);
 }
 
 
@@ -1369,33 +1415,31 @@ static void n_tty_write_wakeup(struct tty_struct *tty)
 static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
                              char *fp, int count)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        const unsigned char *p;
        char *f, flags = TTY_NORMAL;
        int     i;
        char    buf[64];
        unsigned long cpuflags;
 
-       if (!tty->read_buf)
-               return;
-
-       if (tty->real_raw) {
-               spin_lock_irqsave(&tty->read_lock, cpuflags);
-               i = min(N_TTY_BUF_SIZE - tty->read_cnt,
-                       N_TTY_BUF_SIZE - tty->read_head);
+       if (ldata->real_raw) {
+               spin_lock_irqsave(&ldata->read_lock, cpuflags);
+               i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
+                       N_TTY_BUF_SIZE - ldata->read_head);
                i = min(count, i);
-               memcpy(tty->read_buf + tty->read_head, cp, i);
-               tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
-               tty->read_cnt += i;
+               memcpy(ldata->read_buf + ldata->read_head, cp, i);
+               ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
+               ldata->read_cnt += i;
                cp += i;
                count -= i;
 
-               i = min(N_TTY_BUF_SIZE - tty->read_cnt,
-                       N_TTY_BUF_SIZE - tty->read_head);
+               i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
+                       N_TTY_BUF_SIZE - ldata->read_head);
                i = min(count, i);
-               memcpy(tty->read_buf + tty->read_head, cp, i);
-               tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
-               tty->read_cnt += i;
-               spin_unlock_irqrestore(&tty->read_lock, cpuflags);
+               memcpy(ldata->read_buf + ldata->read_head, cp, i);
+               ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
+               ldata->read_cnt += i;
+               spin_unlock_irqrestore(&ldata->read_lock, cpuflags);
        } else {
                for (i = count, p = cp, f = fp; i; i--, p++) {
                        if (f)
@@ -1426,7 +1470,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 
        n_tty_set_room(tty);
 
-       if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) ||
+       if ((!ldata->icanon && (ldata->read_cnt >= tty->minimum_to_wake)) ||
                L_EXTPROC(tty)) {
                kill_fasync(&tty->fasync, SIGIO, POLL_IN);
                if (waitqueue_active(&tty->read_wait))
@@ -1470,25 +1514,25 @@ int is_ignored(int sig)
 
 static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int canon_change = 1;
-       BUG_ON(!tty);
 
        if (old)
                canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
        if (canon_change) {
-               memset(&tty->read_flags, 0, sizeof tty->read_flags);
-               tty->canon_head = tty->read_tail;
-               tty->canon_data = 0;
-               tty->erasing = 0;
+               bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
+               ldata->canon_head = ldata->read_tail;
+               ldata->canon_data = 0;
+               ldata->erasing = 0;
        }
 
-       if (canon_change && !L_ICANON(tty) && tty->read_cnt)
+       if (canon_change && !L_ICANON(tty) && ldata->read_cnt)
                wake_up_interruptible(&tty->read_wait);
 
-       tty->icanon = (L_ICANON(tty) != 0);
+       ldata->icanon = (L_ICANON(tty) != 0);
        if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
-               tty->raw = 1;
-               tty->real_raw = 1;
+               ldata->raw = 1;
+               ldata->real_raw = 1;
                n_tty_set_room(tty);
                return;
        }
@@ -1496,51 +1540,51 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
            I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
            I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
            I_PARMRK(tty)) {
-               memset(tty->process_char_map, 0, 256/8);
+               bitmap_zero(ldata->process_char_map, 256);
 
                if (I_IGNCR(tty) || I_ICRNL(tty))
-                       set_bit('\r', tty->process_char_map);
+                       set_bit('\r', ldata->process_char_map);
                if (I_INLCR(tty))
-                       set_bit('\n', tty->process_char_map);
+                       set_bit('\n', ldata->process_char_map);
 
                if (L_ICANON(tty)) {
-                       set_bit(ERASE_CHAR(tty), tty->process_char_map);
-                       set_bit(KILL_CHAR(tty), tty->process_char_map);
-                       set_bit(EOF_CHAR(tty), tty->process_char_map);
-                       set_bit('\n', tty->process_char_map);
-                       set_bit(EOL_CHAR(tty), tty->process_char_map);
+                       set_bit(ERASE_CHAR(tty), ldata->process_char_map);
+                       set_bit(KILL_CHAR(tty), ldata->process_char_map);
+                       set_bit(EOF_CHAR(tty), ldata->process_char_map);
+                       set_bit('\n', ldata->process_char_map);
+                       set_bit(EOL_CHAR(tty), ldata->process_char_map);
                        if (L_IEXTEN(tty)) {
                                set_bit(WERASE_CHAR(tty),
-                                       tty->process_char_map);
+                                       ldata->process_char_map);
                                set_bit(LNEXT_CHAR(tty),
-                                       tty->process_char_map);
+                                       ldata->process_char_map);
                                set_bit(EOL2_CHAR(tty),
-                                       tty->process_char_map);
+                                       ldata->process_char_map);
                                if (L_ECHO(tty))
                                        set_bit(REPRINT_CHAR(tty),
-                                               tty->process_char_map);
+                                               ldata->process_char_map);
                        }
                }
                if (I_IXON(tty)) {
-                       set_bit(START_CHAR(tty), tty->process_char_map);
-                       set_bit(STOP_CHAR(tty), tty->process_char_map);
+                       set_bit(START_CHAR(tty), ldata->process_char_map);
+                       set_bit(STOP_CHAR(tty), ldata->process_char_map);
                }
                if (L_ISIG(tty)) {
-                       set_bit(INTR_CHAR(tty), tty->process_char_map);
-                       set_bit(QUIT_CHAR(tty), tty->process_char_map);
-                       set_bit(SUSP_CHAR(tty), tty->process_char_map);
+                       set_bit(INTR_CHAR(tty), ldata->process_char_map);
+                       set_bit(QUIT_CHAR(tty), ldata->process_char_map);
+                       set_bit(SUSP_CHAR(tty), ldata->process_char_map);
                }
-               clear_bit(__DISABLED_CHAR, tty->process_char_map);
-               tty->raw = 0;
-               tty->real_raw = 0;
+               clear_bit(__DISABLED_CHAR, ldata->process_char_map);
+               ldata->raw = 0;
+               ldata->real_raw = 0;
        } else {
-               tty->raw = 1;
+               ldata->raw = 1;
                if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
                    (I_IGNPAR(tty) || !I_INPCK(tty)) &&
                    (tty->driver->flags & TTY_DRIVER_REAL_RAW))
-                       tty->real_raw = 1;
+                       ldata->real_raw = 1;
                else
-                       tty->real_raw = 0;
+                       ldata->real_raw = 0;
        }
        n_tty_set_room(tty);
        /* The termios change make the tty ready for I/O */
@@ -1560,15 +1604,13 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 
 static void n_tty_close(struct tty_struct *tty)
 {
+       struct n_tty_data *ldata = tty->disc_data;
+
        n_tty_flush_buffer(tty);
-       if (tty->read_buf) {
-               kfree(tty->read_buf);
-               tty->read_buf = NULL;
-       }
-       if (tty->echo_buf) {
-               kfree(tty->echo_buf);
-               tty->echo_buf = NULL;
-       }
+       kfree(ldata->read_buf);
+       kfree(ldata->echo_buf);
+       kfree(ldata);
+       tty->disc_data = NULL;
 }
 
 /**
@@ -1583,37 +1625,50 @@ static void n_tty_close(struct tty_struct *tty)
 
 static int n_tty_open(struct tty_struct *tty)
 {
-       if (!tty)
-               return -EINVAL;
+       struct n_tty_data *ldata;
+
+       ldata = kzalloc(sizeof(*ldata), GFP_KERNEL);
+       if (!ldata)
+               goto err;
+
+       ldata->overrun_time = jiffies;
+       mutex_init(&ldata->atomic_read_lock);
+       mutex_init(&ldata->output_lock);
+       mutex_init(&ldata->echo_lock);
+       spin_lock_init(&ldata->read_lock);
 
        /* These are ugly. Currently a malloc failure here can panic */
-       if (!tty->read_buf) {
-               tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
-               if (!tty->read_buf)
-                       return -ENOMEM;
-       }
-       if (!tty->echo_buf) {
-               tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
+       ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
+       ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
+       if (!ldata->read_buf || !ldata->echo_buf)
+               goto err_free_bufs;
 
-               if (!tty->echo_buf)
-                       return -ENOMEM;
-       }
+       tty->disc_data = ldata;
        reset_buffer_flags(tty);
        tty_unthrottle(tty);
-       tty->column = 0;
+       ldata->column = 0;
        n_tty_set_termios(tty, NULL);
        tty->minimum_to_wake = 1;
        tty->closing = 0;
+
        return 0;
+err_free_bufs:
+       kfree(ldata->read_buf);
+       kfree(ldata->echo_buf);
+       kfree(ldata);
+err:
+       return -ENOMEM;
 }
 
 static inline int input_available_p(struct tty_struct *tty, int amt)
 {
+       struct n_tty_data *ldata = tty->disc_data;
+
        tty_flush_to_ldisc(tty);
-       if (tty->icanon && !L_EXTPROC(tty)) {
-               if (tty->canon_data)
+       if (ldata->icanon && !L_EXTPROC(tty)) {
+               if (ldata->canon_data)
                        return 1;
-       } else if (tty->read_cnt >= (amt ? amt : 1))
+       } else if (ldata->read_cnt >= (amt ? amt : 1))
                return 1;
 
        return 0;
@@ -1632,7 +1687,7 @@ static inline int input_available_p(struct tty_struct *tty, int amt)
  *     buffer, and once to drain the space from the (physical) beginning of
  *     the buffer to head pointer.
  *
- *     Called under the tty->atomic_read_lock sem
+ *     Called under the ldata->atomic_read_lock sem
  *
  */
 
@@ -1641,29 +1696,31 @@ static int copy_from_read_buf(struct tty_struct *tty,
                                      size_t *nr)
 
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int retval;
        size_t n;
        unsigned long flags;
        bool is_eof;
 
        retval = 0;
-       spin_lock_irqsave(&tty->read_lock, flags);
-       n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail);
+       spin_lock_irqsave(&ldata->read_lock, flags);
+       n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail);
        n = min(*nr, n);
-       spin_unlock_irqrestore(&tty->read_lock, flags);
+       spin_unlock_irqrestore(&ldata->read_lock, flags);
        if (n) {
-               retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
+               retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n);
                n -= retval;
                is_eof = n == 1 &&
-                       tty->read_buf[tty->read_tail] == EOF_CHAR(tty);
-               tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
-               spin_lock_irqsave(&tty->read_lock, flags);
-               tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
-               tty->read_cnt -= n;
+                       ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty);
+               tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n,
+                               ldata->icanon);
+               spin_lock_irqsave(&ldata->read_lock, flags);
+               ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1);
+               ldata->read_cnt -= n;
                /* Turn single EOF into zero-length read */
-               if (L_EXTPROC(tty) && tty->icanon && is_eof && !tty->read_cnt)
+               if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt)
                        n = 0;
-               spin_unlock_irqrestore(&tty->read_lock, flags);
+               spin_unlock_irqrestore(&ldata->read_lock, flags);
                *b += n;
                *nr -= n;
        }
@@ -1730,6 +1787,7 @@ static int job_control(struct tty_struct *tty, struct file *file)
 static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
                         unsigned char __user *buf, size_t nr)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        unsigned char __user *b = buf;
        DECLARE_WAITQUEUE(wait, current);
        int c;
@@ -1741,17 +1799,13 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
        int packet;
 
 do_it_again:
-
-       if (WARN_ON(!tty->read_buf))
-               return -EAGAIN;
-
        c = job_control(tty, file);
        if (c < 0)
                return c;
 
        minimum = time = 0;
        timeout = MAX_SCHEDULE_TIMEOUT;
-       if (!tty->icanon) {
+       if (!ldata->icanon) {
                time = (HZ / 10) * TIME_CHAR(tty);
                minimum = MIN_CHAR(tty);
                if (minimum) {
@@ -1774,10 +1828,10 @@ do_it_again:
         *      Internal serialization of reads.
         */
        if (file->f_flags & O_NONBLOCK) {
-               if (!mutex_trylock(&tty->atomic_read_lock))
+               if (!mutex_trylock(&ldata->atomic_read_lock))
                        return -EAGAIN;
        } else {
-               if (mutex_lock_interruptible(&tty->atomic_read_lock))
+               if (mutex_lock_interruptible(&ldata->atomic_read_lock))
                        return -ERESTARTSYS;
        }
        packet = tty->packet;
@@ -1830,7 +1884,6 @@ do_it_again:
                        /* FIXME: does n_tty_set_room need locking ? */
                        n_tty_set_room(tty);
                        timeout = schedule_timeout(timeout);
-                       BUG_ON(!tty->read_buf);
                        continue;
                }
                __set_current_state(TASK_RUNNING);
@@ -1845,45 +1898,45 @@ do_it_again:
                        nr--;
                }
 
-               if (tty->icanon && !L_EXTPROC(tty)) {
+               if (ldata->icanon && !L_EXTPROC(tty)) {
                        /* N.B. avoid overrun if nr == 0 */
-                       spin_lock_irqsave(&tty->read_lock, flags);
-                       while (nr && tty->read_cnt) {
+                       spin_lock_irqsave(&ldata->read_lock, flags);
+                       while (nr && ldata->read_cnt) {
                                int eol;
 
-                               eol = test_and_clear_bit(tty->read_tail,
-                                               tty->read_flags);
-                               c = tty->read_buf[tty->read_tail];
-                               tty->read_tail = ((tty->read_tail+1) &
+                               eol = test_and_clear_bit(ldata->read_tail,
+                                               ldata->read_flags);
+                               c = ldata->read_buf[ldata->read_tail];
+                               ldata->read_tail = ((ldata->read_tail+1) &
                                                  (N_TTY_BUF_SIZE-1));
-                               tty->read_cnt--;
+                               ldata->read_cnt--;
                                if (eol) {
                                        /* this test should be redundant:
                                         * we shouldn't be reading data if
                                         * canon_data is 0
                                         */
-                                       if (--tty->canon_data < 0)
-                                               tty->canon_data = 0;
+                                       if (--ldata->canon_data < 0)
+                                               ldata->canon_data = 0;
                                }
-                               spin_unlock_irqrestore(&tty->read_lock, flags);
+                               spin_unlock_irqrestore(&ldata->read_lock, flags);
 
                                if (!eol || (c != __DISABLED_CHAR)) {
                                        if (tty_put_user(tty, c, b++)) {
                                                retval = -EFAULT;
                                                b--;
-                                               spin_lock_irqsave(&tty->read_lock, flags);
+                                               spin_lock_irqsave(&ldata->read_lock, flags);
                                                break;
                                        }
                                        nr--;
                                }
                                if (eol) {
                                        tty_audit_push(tty);
-                                       spin_lock_irqsave(&tty->read_lock, flags);
+                                       spin_lock_irqsave(&ldata->read_lock, flags);
                                        break;
                                }
-                               spin_lock_irqsave(&tty->read_lock, flags);
+                               spin_lock_irqsave(&ldata->read_lock, flags);
                        }
-                       spin_unlock_irqrestore(&tty->read_lock, flags);
+                       spin_unlock_irqrestore(&ldata->read_lock, flags);
                        if (retval)
                                break;
                } else {
@@ -1915,7 +1968,7 @@ do_it_again:
                if (time)
                        timeout = time;
        }
-       mutex_unlock(&tty->atomic_read_lock);
+       mutex_unlock(&ldata->atomic_read_lock);
        remove_wait_queue(&tty->read_wait, &wait);
 
        if (!waitqueue_active(&tty->read_wait))
@@ -2076,19 +2129,19 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
        return mask;
 }
 
-static unsigned long inq_canon(struct tty_struct *tty)
+static unsigned long inq_canon(struct n_tty_data *ldata)
 {
        int nr, head, tail;
 
-       if (!tty->canon_data)
+       if (!ldata->canon_data)
                return 0;
-       head = tty->canon_head;
-       tail = tty->read_tail;
+       head = ldata->canon_head;
+       tail = ldata->read_tail;
        nr = (head - tail) & (N_TTY_BUF_SIZE-1);
        /* Skip EOF-chars.. */
        while (head != tail) {
-               if (test_bit(tail, tty->read_flags) &&
-                   tty->read_buf[tail] == __DISABLED_CHAR)
+               if (test_bit(tail, ldata->read_flags) &&
+                   ldata->read_buf[tail] == __DISABLED_CHAR)
                        nr--;
                tail = (tail+1) & (N_TTY_BUF_SIZE-1);
        }
@@ -2098,6 +2151,7 @@ static unsigned long inq_canon(struct tty_struct *tty)
 static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
                       unsigned int cmd, unsigned long arg)
 {
+       struct n_tty_data *ldata = tty->disc_data;
        int retval;
 
        switch (cmd) {
@@ -2105,9 +2159,9 @@ static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
                return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
        case TIOCINQ:
                /* FIXME: Locking */
-               retval = tty->read_cnt;
+               retval = ldata->read_cnt;
                if (L_ICANON(tty))
-                       retval = inq_canon(tty);
+                       retval = inq_canon(ldata);
                return put_user(retval, (unsigned int __user *) arg);
        default:
                return n_tty_ioctl_helper(tty, file, cmd, arg);