tty: some ICANON magic is in the wrong places

Move the set up on ldisc change into the ldisc
Move the INQ/OUTQ cases into the driver not in shared ioctl code where it
gives bogus answers for other ldisc values

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 54 insertions, 43 deletions

diff --git a/drivers/char/n_hdlc.c b/drivers/char/n_hdlc.c
index 69ec6399c714..bacb3e2872ae 100644
--- a/drivers/char/n_hdlc.c
+++ b/drivers/char/n_hdlc.c
@@ -764,7 +764,7 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
                 break;
 
         default:
-                error = n_tty_ioctl (tty, file, cmd, arg);
+                error = n_tty_ioctl_helper(tty, file, cmd, arg);
                 break;
         }
         return error;
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 708c2b1dbe51..b4f5dccad2a6 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1011,8 +1011,20 @@ int is_ignored(int sig)
 
 static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 {
-        if (!tty)
-                return;
+        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;
+        }
+
+        if (canon_change && !L_ICANON(tty) && tty->read_cnt)
+                wake_up_interruptible(&tty->read_wait);
 
         tty->icanon = (L_ICANON(tty) != 0);
         if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
@@ -1573,6 +1585,43 @@ static unsigned int normal_poll(struct tty_struct *tty, struct file *file,
         return mask;
 }
 
+static unsigned long inq_canon(struct tty_struct *tty)
+{
+        int nr, head, tail;
+
+        if (!tty->canon_data || !tty->read_buf)
+                return 0;
+        head = tty->canon_head;
+        tail = tty->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)
+                        nr--;
+                tail = (tail+1) & (N_TTY_BUF_SIZE-1);
+        }
+        return nr;
+}
+
+static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+                       unsigned int cmd, unsigned long arg)
+{
+        int retval;
+
+        switch (cmd) {
+        case TIOCOUTQ:
+                return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
+        case TIOCINQ:
+                retval = tty->read_cnt;
+                if (L_ICANON(tty))
+                        retval = inq_canon(tty);
+                return put_user(retval, (unsigned int __user *) arg);
+        default:
+                return n_tty_ioctl_helper(tty, file, cmd, arg);
+        }
+}
+
 struct tty_ldisc_ops tty_ldisc_N_TTY = {
         .magic           = TTY_LDISC_MAGIC,
         .name            = "n_tty",
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 14cc19c344cc..a408c8e487ec 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -489,7 +489,6 @@ EXPORT_SYMBOL(tty_termios_hw_change);
 
 static void change_termios(struct tty_struct *tty, struct ktermios *new_termios)
 {
-        int canon_change;
         struct ktermios old_termios;
         struct tty_ldisc *ld;
         unsigned long flags;
@@ -505,18 +504,6 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios)
         old_termios = *tty->termios;
         *tty->termios = *new_termios;
         unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
-        canon_change = (old_termios.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;
-        }
-
-        /* This bit should be in the ldisc code */
-        if (canon_change && !L_ICANON(tty) && tty->read_cnt)
-                /* Get characters left over from canonical mode. */
-                wake_up_interruptible(&tty->read_wait);
 
         /* See if packet mode change of state. */
         if (tty->link && tty->link->packet) {
@@ -677,24 +664,6 @@ static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
 
 #endif
 
-static unsigned long inq_canon(struct tty_struct *tty)
-{
-        int nr, head, tail;
-
-        if (!tty->canon_data || !tty->read_buf)
-                return 0;
-        head = tty->canon_head;
-        tail = tty->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)
-                        nr--;
-                tail = (tail+1) & (N_TTY_BUF_SIZE-1);
-        }
-        return nr;
-}
 
 #ifdef TIOCGETP
 /*
@@ -1110,7 +1079,7 @@ int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
 }
 EXPORT_SYMBOL_GPL(tty_perform_flush);
 
-int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
                        unsigned int cmd, unsigned long arg)
 {
         unsigned long flags;
@@ -1148,13 +1117,6 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file,
                 return 0;
         case TCFLSH:
                 return tty_perform_flush(tty, arg);
-        case TIOCOUTQ:
-                return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
-        case TIOCINQ:
-                retval = tty->read_cnt;
-                if (L_ICANON(tty))
-                        retval = inq_canon(tty);
-                return put_user(retval, (unsigned int __user *) arg);
         case TIOCPKT:
         {
                 int pktmode;
@@ -1180,4 +1142,4 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file,
                 return tty_mode_ioctl(tty, file, cmd, arg);
         }
 }
-EXPORT_SYMBOL(n_tty_ioctl);
+EXPORT_SYMBOL(n_tty_ioctl_helper);