device create: char: convert device_create to device_create_drvdata
[safe/jmp/linux-2.6] / drivers / char / tty_io.c
index 613ec81..dc9202d 100644 (file)
@@ -78,6 +78,7 @@
 #include <linux/tty_flip.h>
 #include <linux/devpts_fs.h>
 #include <linux/file.h>
+#include <linux/fdtable.h>
 #include <linux/console.h>
 #include <linux/timer.h>
 #include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>
 #include <linux/device.h>
-#include <linux/idr.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
+#include <linux/seq_file.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <asm/system.h>
 
 #include <linux/kbd_kern.h>
@@ -137,9 +138,6 @@ EXPORT_SYMBOL(tty_mutex);
 
 #ifdef CONFIG_UNIX98_PTYS
 extern struct tty_driver *ptm_driver;  /* Unix98 pty masters; for /dev/ptmx */
-extern int pty_limit;                  /* Config limit on Unix98 ptys */
-static DEFINE_IDR(allocated_ptys);
-static DEFINE_MUTEX(allocated_ptys_lock);
 static int ptmx_open(struct inode *, struct file *);
 #endif
 
@@ -152,8 +150,7 @@ ssize_t redirected_tty_write(struct file *, const char __user *,
 static unsigned int tty_poll(struct file *, poll_table *);
 static int tty_open(struct inode *, struct file *);
 static int tty_release(struct inode *, struct file *);
-int tty_ioctl(struct inode *inode, struct file *file,
-             unsigned int cmd, unsigned long arg);
+long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 #ifdef CONFIG_COMPAT
 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
                                unsigned long arg);
@@ -686,7 +683,7 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 static DEFINE_SPINLOCK(tty_ldisc_lock);
 static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
 /* Line disc dispatch table */
-static struct tty_ldisc tty_ldiscs[NR_LDISCS];
+static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
 
 /**
  *     tty_register_ldisc      -       install a line discipline
@@ -701,7 +698,7 @@ static struct tty_ldisc tty_ldiscs[NR_LDISCS];
  *             takes tty_ldisc_lock to guard against ldisc races
  */
 
-int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
+int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc)
 {
        unsigned long flags;
        int ret = 0;
@@ -710,10 +707,9 @@ int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
                return -EINVAL;
 
        spin_lock_irqsave(&tty_ldisc_lock, flags);
-       tty_ldiscs[disc] = *new_ldisc;
-       tty_ldiscs[disc].num = disc;
-       tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
-       tty_ldiscs[disc].refcount = 0;
+       tty_ldiscs[disc] = new_ldisc;
+       new_ldisc->num = disc;
+       new_ldisc->refcount = 0;
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
 
        return ret;
@@ -741,19 +737,56 @@ int tty_unregister_ldisc(int disc)
                return -EINVAL;
 
        spin_lock_irqsave(&tty_ldisc_lock, flags);
-       if (tty_ldiscs[disc].refcount)
+       if (tty_ldiscs[disc]->refcount)
                ret = -EBUSY;
        else
-               tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED;
+               tty_ldiscs[disc] = NULL;
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
 
        return ret;
 }
 EXPORT_SYMBOL(tty_unregister_ldisc);
 
+
+/**
+ *     tty_ldisc_try_get       -       try and reference an ldisc
+ *     @disc: ldisc number
+ *     @ld: tty ldisc structure to complete
+ *
+ *     Attempt to open and lock a line discipline into place. Return
+ *     the line discipline refcounted and assigned in ld. On an error
+ *     report the error code back
+ */
+
+static int tty_ldisc_try_get(int disc, struct tty_ldisc *ld)
+{
+       unsigned long flags;
+       struct tty_ldisc_ops *ldops;
+       int err = -EINVAL;
+       
+       spin_lock_irqsave(&tty_ldisc_lock, flags);
+       ld->ops = NULL;
+       ldops = tty_ldiscs[disc];
+       /* Check the entry is defined */
+       if (ldops) {
+               /* If the module is being unloaded we can't use it */
+               if (!try_module_get(ldops->owner))
+                       err = -EAGAIN;
+               else {
+                       /* lock it */
+                       ldops->refcount++;
+                       ld->ops = ldops;
+                       err = 0;
+               }
+       }
+       spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+       return err;
+}
+
 /**
  *     tty_ldisc_get           -       take a reference to an ldisc
  *     @disc: ldisc number
+ *     @ld: tty line discipline structure to use
  *
  *     Takes a reference to a line discipline. Deals with refcounts and
  *     module locking counts. Returns NULL if the discipline is not available.
@@ -764,32 +797,20 @@ EXPORT_SYMBOL(tty_unregister_ldisc);
  *             takes tty_ldisc_lock to guard against ldisc races
  */
 
-struct tty_ldisc *tty_ldisc_get(int disc)
+static int tty_ldisc_get(int disc, struct tty_ldisc *ld)
 {
-       unsigned long flags;
-       struct tty_ldisc *ld;
+       int err;
 
        if (disc < N_TTY || disc >= NR_LDISCS)
-               return NULL;
-
-       spin_lock_irqsave(&tty_ldisc_lock, flags);
-
-       ld = &tty_ldiscs[disc];
-       /* Check the entry is defined */
-       if (ld->flags & LDISC_FLAG_DEFINED) {
-               /* If the module is being unloaded we can't use it */
-               if (!try_module_get(ld->owner))
-                       ld = NULL;
-               else /* lock it */
-                       ld->refcount++;
-       } else
-               ld = NULL;
-       spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-       return ld;
+               return -EINVAL;
+       err = tty_ldisc_try_get(disc, ld);
+       if (err == -EAGAIN) {
+               request_module("tty-ldisc-%d", disc);
+               err = tty_ldisc_try_get(disc, ld);
+       }
+       return err;
 }
 
-EXPORT_SYMBOL_GPL(tty_ldisc_get);
-
 /**
  *     tty_ldisc_put           -       drop ldisc reference
  *     @disc: ldisc number
@@ -801,22 +822,67 @@ EXPORT_SYMBOL_GPL(tty_ldisc_get);
  *             takes tty_ldisc_lock to guard against ldisc races
  */
 
-void tty_ldisc_put(int disc)
+static void tty_ldisc_put(struct tty_ldisc_ops *ld)
 {
-       struct tty_ldisc *ld;
        unsigned long flags;
+       int disc = ld->num;
 
        BUG_ON(disc < N_TTY || disc >= NR_LDISCS);
 
        spin_lock_irqsave(&tty_ldisc_lock, flags);
-       ld = &tty_ldiscs[disc];
+       ld = tty_ldiscs[disc];
        BUG_ON(ld->refcount == 0);
        ld->refcount--;
        module_put(ld->owner);
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
 }
 
-EXPORT_SYMBOL_GPL(tty_ldisc_put);
+static void * tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos)
+{
+       return (*pos < NR_LDISCS) ? pos : NULL;
+}
+
+static void * tty_ldiscs_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+       (*pos)++;
+       return (*pos < NR_LDISCS) ? pos : NULL;
+}
+
+static void tty_ldiscs_seq_stop(struct seq_file *m, void *v)
+{
+}
+
+static int tty_ldiscs_seq_show(struct seq_file *m, void *v)
+{
+       int i = *(loff_t *)v;
+       struct tty_ldisc ld;
+       
+       if (tty_ldisc_get(i, &ld) < 0)
+               return 0;
+       seq_printf(m, "%-10s %2d\n", ld.ops->name ? ld.ops->name : "???", i);
+       tty_ldisc_put(ld.ops);
+       return 0;
+}
+
+static const struct seq_operations tty_ldiscs_seq_ops = {
+       .start  = tty_ldiscs_seq_start,
+       .next   = tty_ldiscs_seq_next,
+       .stop   = tty_ldiscs_seq_stop,
+       .show   = tty_ldiscs_seq_show,
+};
+
+static int proc_tty_ldiscs_open(struct inode *inode, struct file *file)
+{
+       return seq_open(file, &tty_ldiscs_seq_ops);
+}
+
+const struct file_operations tty_ldiscs_proc_fops = {
+       .owner          = THIS_MODULE,
+       .open           = proc_tty_ldiscs_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release,
+};
 
 /**
  *     tty_ldisc_assign        -       set ldisc on a tty
@@ -833,8 +899,8 @@ EXPORT_SYMBOL_GPL(tty_ldisc_put);
 
 static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld)
 {
+       ld->refcount = 0;
        tty->ldisc = *ld;
-       tty->ldisc.refcount = 0;
 }
 
 /**
@@ -958,6 +1024,41 @@ static void tty_ldisc_enable(struct tty_struct *tty)
 }
 
 /**
+ *     tty_ldisc_restore       -       helper for tty ldisc change
+ *     @tty: tty to recover
+ *     @old: previous ldisc
+ *
+ *     Restore the previous line discipline or N_TTY when a line discipline
+ *     change fails due to an open error
+ */
+
+static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
+{
+       char buf[64];
+       struct tty_ldisc new_ldisc;
+
+       /* There is an outstanding reference here so this is safe */
+       tty_ldisc_get(old->ops->num, old);
+       tty_ldisc_assign(tty, old);
+       tty_set_termios_ldisc(tty, old->ops->num);
+       if (old->ops->open && (old->ops->open(tty) < 0)) {
+               tty_ldisc_put(old->ops);
+               /* This driver is always present */
+               if (tty_ldisc_get(N_TTY, &new_ldisc) < 0)
+                       panic("n_tty: get");
+               tty_ldisc_assign(tty, &new_ldisc);
+               tty_set_termios_ldisc(tty, N_TTY);
+               if (new_ldisc.ops->open) {
+                       int r = new_ldisc.ops->open(tty);
+                               if (r < 0)
+                               panic("Couldn't open N_TTY ldisc for "
+                                     "%s --- error %d.",
+                                     tty_name(tty, buf), r);
+               }
+       }
+}
+
+/**
  *     tty_set_ldisc           -       set line discipline
  *     @tty: the terminal to set
  *     @ldisc: the line discipline
@@ -971,28 +1072,18 @@ static void tty_ldisc_enable(struct tty_struct *tty)
 
 static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 {
-       int retval = 0;
-       struct tty_ldisc o_ldisc;
-       char buf[64];
+       int retval;
+       struct tty_ldisc o_ldisc, new_ldisc;
        int work;
        unsigned long flags;
-       struct tty_ldisc *ld;
        struct tty_struct *o_tty;
 
-       if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS))
-               return -EINVAL;
-
 restart:
-
-       ld = tty_ldisc_get(ldisc);
-       /* Eduardo Blanco <ejbs@cs.cs.com.uy> */
-       /* Cyrus Durgin <cider@speakeasy.org> */
-       if (ld == NULL) {
-               request_module("tty-ldisc-%d", ldisc);
-               ld = tty_ldisc_get(ldisc);
-       }
-       if (ld == NULL)
-               return -EINVAL;
+       /* This is a bit ugly for now but means we can break the 'ldisc
+          is part of the tty struct' assumption later */
+       retval = tty_ldisc_get(ldisc, &new_ldisc);
+       if (retval)
+               return retval;
 
        /*
         *      Problem: What do we do if this blocks ?
@@ -1000,8 +1091,8 @@ restart:
 
        tty_wait_until_sent(tty, 0);
 
-       if (tty->ldisc.num == ldisc) {
-               tty_ldisc_put(ldisc);
+       if (tty->ldisc.ops->num == ldisc) {
+               tty_ldisc_put(new_ldisc.ops);
                return 0;
        }
 
@@ -1028,7 +1119,7 @@ restart:
                        /* Free the new ldisc we grabbed. Must drop the lock
                           first. */
                        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-                       tty_ldisc_put(ldisc);
+                       tty_ldisc_put(o_ldisc.ops);
                        /*
                         * There are several reasons we may be busy, including
                         * random momentary I/O traffic. We must therefore
@@ -1042,7 +1133,7 @@ restart:
                }
                if (o_tty && o_tty->ldisc.refcount) {
                        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-                       tty_ldisc_put(ldisc);
+                       tty_ldisc_put(o_tty->ldisc.ops);
                        if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0)
                                return -ERESTARTSYS;
                        goto restart;
@@ -1053,8 +1144,9 @@ restart:
         *      another ldisc change
         */
        if (!test_bit(TTY_LDISC, &tty->flags)) {
+               struct tty_ldisc *ld;
                spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-               tty_ldisc_put(ldisc);
+               tty_ldisc_put(new_ldisc.ops);
                ld = tty_ldisc_ref_wait(tty);
                tty_ldisc_deref(ld);
                goto restart;
@@ -1064,7 +1156,7 @@ restart:
        if (o_tty)
                clear_bit(TTY_LDISC, &o_tty->flags);
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-
+       
        /*
         *      From this point on we know nobody has an ldisc
         *      usage reference, nor can they obtain one until
@@ -1074,45 +1166,30 @@ restart:
        work = cancel_delayed_work(&tty->buf.work);
        /*
         * Wait for ->hangup_work and ->buf.work handlers to terminate
+        * MUST NOT hold locks here.
         */
        flush_scheduled_work();
        /* Shutdown the current discipline. */
-       if (tty->ldisc.close)
-               (tty->ldisc.close)(tty);
+       if (o_ldisc.ops->close)
+               (o_ldisc.ops->close)(tty);
 
        /* Now set up the new line discipline. */
-       tty_ldisc_assign(tty, ld);
+       tty_ldisc_assign(tty, &new_ldisc);
        tty_set_termios_ldisc(tty, ldisc);
-       if (tty->ldisc.open)
-               retval = (tty->ldisc.open)(tty);
+       if (new_ldisc.ops->open)
+               retval = (new_ldisc.ops->open)(tty);
        if (retval < 0) {
-               tty_ldisc_put(ldisc);
-               /* There is an outstanding reference here so this is safe */
-               tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num));
-               tty_set_termios_ldisc(tty, tty->ldisc.num);
-               if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) {
-                       tty_ldisc_put(o_ldisc.num);
-                       /* This driver is always present */
-                       tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
-                       tty_set_termios_ldisc(tty, N_TTY);
-                       if (tty->ldisc.open) {
-                               int r = tty->ldisc.open(tty);
-
-                               if (r < 0)
-                                       panic("Couldn't open N_TTY ldisc for "
-                                             "%s --- error %d.",
-                                             tty_name(tty, buf), r);
-                       }
-               }
+               tty_ldisc_put(new_ldisc.ops);
+               tty_ldisc_restore(tty, &o_ldisc);
        }
        /* At this point we hold a reference to the new ldisc and a
           a reference to the old ldisc. If we ended up flipping back
           to the existing ldisc we have two references to it */
 
-       if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc)
-               tty->driver->set_ldisc(tty);
+       if (tty->ldisc.ops->num != o_ldisc.ops->num && tty->ops->set_ldisc)
+               tty->ops->set_ldisc(tty);
 
-       tty_ldisc_put(o_ldisc.num);
+       tty_ldisc_put(o_ldisc.ops);
 
        /*
         *      Allow ldisc referencing to occur as soon as the driver
@@ -1155,6 +1232,47 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
        return NULL;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+
+/**
+ *     tty_find_polling_driver -       find device of a polled tty
+ *     @name: name string to match
+ *     @line: pointer to resulting tty line nr
+ *
+ *     This routine returns a tty driver structure, given a name
+ *     and the condition that the tty driver is capable of polled
+ *     operation.
+ */
+struct tty_driver *tty_find_polling_driver(char *name, int *line)
+{
+       struct tty_driver *p, *res = NULL;
+       int tty_line = 0;
+       char *str;
+
+       mutex_lock(&tty_mutex);
+       /* Search through the tty devices to look for a match */
+       list_for_each_entry(p, &tty_drivers, tty_drivers) {
+               str = name + strlen(p->name);
+               tty_line = simple_strtoul(str, &str, 10);
+               if (*str == ',')
+                       str++;
+               if (*str == '\0')
+                       str = NULL;
+
+               if (tty_line >= 0 && tty_line <= p->num && p->ops &&
+                   p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) {
+                       res = p;
+                       *line = tty_line;
+                       break;
+               }
+       }
+       mutex_unlock(&tty_mutex);
+
+       return res;
+}
+EXPORT_SYMBOL_GPL(tty_find_polling_driver);
+#endif
+
 /**
  *     tty_check_change        -       check for POSIX terminal changes
  *     @tty: tty to check
@@ -1163,26 +1281,40 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
  *     not in the foreground, send a SIGTTOU.  If the signal is blocked or
  *     ignored, go ahead and perform the operation.  (POSIX 7.2)
  *
- *     Locking: none
+ *     Locking: ctrl_lock
  */
 
 int tty_check_change(struct tty_struct *tty)
 {
+       unsigned long flags;
+       int ret = 0;
+
        if (current->signal->tty != tty)
                return 0;
+
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
+
        if (!tty->pgrp) {
                printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
-               return 0;
+               goto out_unlock;
        }
        if (task_pgrp(current) == tty->pgrp)
-               return 0;
+               goto out_unlock;
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (is_ignored(SIGTTOU))
-               return 0;
-       if (is_current_pgrp_orphaned())
-               return -EIO;
+               goto out;
+       if (is_current_pgrp_orphaned()) {
+               ret = -EIO;
+               goto out;
+       }
        kill_pgrp(task_pgrp(current), SIGTTOU, 1);
        set_thread_flag(TIF_SIGPENDING);
-       return -ERESTARTSYS;
+       ret = -ERESTARTSYS;
+out:
+       return ret;
+out_unlock:
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       return ret;
 }
 
 EXPORT_SYMBOL(tty_check_change);
@@ -1205,8 +1337,8 @@ static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
        return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
 }
 
-static int hung_up_tty_ioctl(struct inode *inode, struct file *file,
-                            unsigned int cmd, unsigned long arg)
+static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
+               unsigned long arg)
 {
        return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
 }
@@ -1222,7 +1354,7 @@ static const struct file_operations tty_fops = {
        .read           = tty_read,
        .write          = tty_write,
        .poll           = tty_poll,
-       .ioctl          = tty_ioctl,
+       .unlocked_ioctl = tty_ioctl,
        .compat_ioctl   = tty_compat_ioctl,
        .open           = tty_open,
        .release        = tty_release,
@@ -1235,7 +1367,7 @@ static const struct file_operations ptmx_fops = {
        .read           = tty_read,
        .write          = tty_write,
        .poll           = tty_poll,
-       .ioctl          = tty_ioctl,
+       .unlocked_ioctl = tty_ioctl,
        .compat_ioctl   = tty_compat_ioctl,
        .open           = ptmx_open,
        .release        = tty_release,
@@ -1248,7 +1380,7 @@ static const struct file_operations console_fops = {
        .read           = tty_read,
        .write          = redirected_tty_write,
        .poll           = tty_poll,
-       .ioctl          = tty_ioctl,
+       .unlocked_ioctl = tty_ioctl,
        .compat_ioctl   = tty_compat_ioctl,
        .open           = tty_open,
        .release        = tty_release,
@@ -1260,7 +1392,7 @@ static const struct file_operations hung_up_tty_fops = {
        .read           = hung_up_tty_read,
        .write          = hung_up_tty_write,
        .poll           = hung_up_tty_poll,
-       .ioctl          = hung_up_tty_ioctl,
+       .unlocked_ioctl = hung_up_tty_ioctl,
        .compat_ioctl   = hung_up_tty_compat_ioctl,
        .release        = tty_release,
 };
@@ -1284,8 +1416,8 @@ void tty_wakeup(struct tty_struct *tty)
        if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
                ld = tty_ldisc_ref(tty);
                if (ld) {
-                       if (ld->write_wakeup)
-                               ld->write_wakeup(tty);
+                       if (ld->ops->write_wakeup)
+                               ld->ops->write_wakeup(tty);
                        tty_ldisc_deref(ld);
                }
        }
@@ -1306,8 +1438,8 @@ void tty_ldisc_flush(struct tty_struct *tty)
 {
        struct tty_ldisc *ld = tty_ldisc_ref(tty);
        if (ld) {
-               if (ld->flush_buffer)
-                       ld->flush_buffer(tty);
+               if (ld->ops->flush_buffer)
+                       ld->ops->flush_buffer(tty);
                tty_ldisc_deref(ld);
        }
        tty_buffer_flush(tty);
@@ -1335,7 +1467,7 @@ static void tty_reset_termios(struct tty_struct *tty)
  *     do_tty_hangup           -       actual handler for hangup events
  *     @work: tty device
  *
- *     This can be called by the "eventd" kernel thread.  That is process
+k *    This can be called by the "eventd" kernel thread.  That is process
  *     synchronous but doesn't hold any locks, so we need to make sure we
  *     have the appropriate locks for what we're doing.
  *
@@ -1362,6 +1494,7 @@ static void do_tty_hangup(struct work_struct *work)
        struct task_struct *p;
        struct tty_ldisc *ld;
        int    closecount = 0, n;
+       unsigned long flags;
 
        if (!tty)
                return;
@@ -1397,15 +1530,14 @@ static void do_tty_hangup(struct work_struct *work)
        ld = tty_ldisc_ref(tty);
        if (ld != NULL) {
                /* We may have no line discipline at this point */
-               if (ld->flush_buffer)
-                       ld->flush_buffer(tty);
-               if (tty->driver->flush_buffer)
-                       tty->driver->flush_buffer(tty);
+               if (ld->ops->flush_buffer)
+                       ld->ops->flush_buffer(tty);
+               tty_driver_flush_buffer(tty);
                if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
-                   ld->write_wakeup)
-                       ld->write_wakeup(tty);
-               if (ld->hangup)
-                       ld->hangup(tty);
+                   ld->ops->write_wakeup)
+                       ld->ops->write_wakeup(tty);
+               if (ld->ops->hangup)
+                       ld->ops->hangup(tty);
        }
        /*
         * FIXME: Once we trust the LDISC code better we can wait here for
@@ -1438,19 +1570,24 @@ static void do_tty_hangup(struct work_struct *work)
                        __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
                        __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
                        put_pid(p->signal->tty_old_pgrp);  /* A noop */
+                       spin_lock_irqsave(&tty->ctrl_lock, flags);
                        if (tty->pgrp)
                                p->signal->tty_old_pgrp = get_pid(tty->pgrp);
+                       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                        spin_unlock_irq(&p->sighand->siglock);
                } while_each_pid_task(tty->session, PIDTYPE_SID, p);
        }
        read_unlock(&tasklist_lock);
 
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
        tty->flags = 0;
        put_pid(tty->session);
        put_pid(tty->pgrp);
        tty->session = NULL;
        tty->pgrp = NULL;
        tty->ctrl_status = 0;
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
        /*
         * If one of the devices matches a console pointer, we
         * cannot just call hangup() because that will cause
@@ -1458,11 +1595,11 @@ static void do_tty_hangup(struct work_struct *work)
         * So we just call close() the right number of times.
         */
        if (cons_filp) {
-               if (tty->driver->close)
+               if (tty->ops->close)
                        for (n = 0; n < closecount; n++)
-                               tty->driver->close(tty, cons_filp);
-       } else if (tty->driver->hangup)
-               (tty->driver->hangup)(tty);
+                               tty->ops->close(tty, cons_filp);
+       } else if (tty->ops->hangup)
+               (tty->ops->hangup)(tty);
        /*
         * We don't want to have driver/ldisc interactions beyond
         * the ones we did here. The driver layer expects no
@@ -1584,16 +1721,17 @@ void disassociate_ctty(int on_exit)
        struct tty_struct *tty;
        struct pid *tty_pgrp = NULL;
 
-       lock_kernel();
 
        mutex_lock(&tty_mutex);
        tty = get_current_tty();
        if (tty) {
                tty_pgrp = get_pid(tty->pgrp);
                mutex_unlock(&tty_mutex);
+               lock_kernel();
                /* XXX: here we race, there is nothing protecting tty */
                if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
                        tty_vhangup(tty);
+               unlock_kernel();
        } else if (on_exit) {
                struct pid *old_pgrp;
                spin_lock_irq(&current->sighand->siglock);
@@ -1606,7 +1744,6 @@ void disassociate_ctty(int on_exit)
                        put_pid(old_pgrp);
                }
                mutex_unlock(&tty_mutex);
-               unlock_kernel();
                return;
        }
        if (tty_pgrp) {
@@ -1625,10 +1762,13 @@ void disassociate_ctty(int on_exit)
        /* It is possible that do_tty_hangup has free'd this tty */
        tty = get_current_tty();
        if (tty) {
+               unsigned long flags;
+               spin_lock_irqsave(&tty->ctrl_lock, flags);
                put_pid(tty->session);
                put_pid(tty->pgrp);
                tty->session = NULL;
                tty->pgrp = NULL;
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        } else {
 #ifdef TTY_DEBUG_HANGUP
                printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
@@ -1641,7 +1781,6 @@ void disassociate_ctty(int on_exit)
        read_lock(&tasklist_lock);
        session_clear_tty(task_session(current));
        read_unlock(&tasklist_lock);
-       unlock_kernel();
 }
 
 /**
@@ -1651,8 +1790,10 @@ void disassociate_ctty(int on_exit)
 void no_tty(void)
 {
        struct task_struct *tsk = current;
+       lock_kernel();
        if (tsk->signal->leader)
                disassociate_ctty(0);
+       unlock_kernel();
        proc_clear_tty(tsk);
 }
 
@@ -1672,21 +1813,26 @@ void no_tty(void)
  *     but not always.
  *
  *     Locking:
- *             Broken. Relies on BKL which is unsafe here.
+ *             Uses the tty control lock internally
  */
 
 void stop_tty(struct tty_struct *tty)
 {
-       if (tty->stopped)
+       unsigned long flags;
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
+       if (tty->stopped) {
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                return;
+       }
        tty->stopped = 1;
        if (tty->link && tty->link->packet) {
                tty->ctrl_status &= ~TIOCPKT_START;
                tty->ctrl_status |= TIOCPKT_STOP;
                wake_up_interruptible(&tty->link->read_wait);
        }
-       if (tty->driver->stop)
-               (tty->driver->stop)(tty);
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (tty->ops->stop)
+               (tty->ops->stop)(tty);
 }
 
 EXPORT_SYMBOL(stop_tty);
@@ -1701,21 +1847,26 @@ EXPORT_SYMBOL(stop_tty);
  *     driver start method is invoked and the line discipline woken.
  *
  *     Locking:
- *             Broken. Relies on BKL which is unsafe here.
+ *             ctrl_lock
  */
 
 void start_tty(struct tty_struct *tty)
 {
-       if (!tty->stopped || tty->flow_stopped)
+       unsigned long flags;
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
+       if (!tty->stopped || tty->flow_stopped) {
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                return;
+       }
        tty->stopped = 0;
        if (tty->link && tty->link->packet) {
                tty->ctrl_status &= ~TIOCPKT_STOP;
                tty->ctrl_status |= TIOCPKT_START;
                wake_up_interruptible(&tty->link->read_wait);
        }
-       if (tty->driver->start)
-               (tty->driver->start)(tty);
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (tty->ops->start)
+               (tty->ops->start)(tty);
        /* If we have a running line discipline it may need kicking */
        tty_wakeup(tty);
 }
@@ -1733,10 +1884,8 @@ EXPORT_SYMBOL(start_tty);
  *     for hung up devices before calling the line discipline method.
  *
  *     Locking:
- *             Locks the line discipline internally while needed
- *             For historical reasons the line discipline read method is
- *     invoked under the BKL. This will go away in time so do not rely on it
- *     in new code. Multiple read calls may be outstanding in parallel.
+ *             Locks the line discipline internally while needed. Multiple
+ *     read calls may be outstanding in parallel.
  */
 
 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
@@ -1757,13 +1906,11 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
        /* We want to wait for the line discipline to sort out in this
           situation */
        ld = tty_ldisc_ref_wait(tty);
-       lock_kernel();
-       if (ld->read)
-               i = (ld->read)(tty, file, buf, count);
+       if (ld->ops->read)
+               i = (ld->ops->read)(tty, file, buf, count);
        else
                i = -EIO;
        tty_ldisc_deref(ld);
-       unlock_kernel();
        if (i > 0)
                inode->i_atime = current_fs_time(inode->i_sb);
        return i;
@@ -1851,9 +1998,7 @@ static inline ssize_t do_tty_write(
                ret = -EFAULT;
                if (copy_from_user(tty->write_buf, buf, size))
                        break;
-               lock_kernel();
                ret = write(tty, file, tty->write_buf, size);
-               unlock_kernel();
                if (ret <= 0)
                        break;
                written += ret;
@@ -1906,15 +2051,18 @@ static ssize_t tty_write(struct file *file, const char __user *buf,
        tty = (struct tty_struct *)file->private_data;
        if (tty_paranoia_check(tty, inode, "tty_write"))
                return -EIO;
-       if (!tty || !tty->driver->write ||
+       if (!tty || !tty->ops->write ||
                (test_bit(TTY_IO_ERROR, &tty->flags)))
                        return -EIO;
-
+       /* Short term debug to catch buggy drivers */
+       if (tty->ops->write_room == NULL)
+               printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
+                       tty->driver->name);
        ld = tty_ldisc_ref_wait(tty);
-       if (!ld->write)
+       if (!ld->ops->write)
                ret = -EIO;
        else
-               ret = do_tty_write(ld->write, tty, file, buf, count);
+               ret = do_tty_write(ld->ops->write, tty, file, buf, count);
        tty_ldisc_deref(ld);
        return ret;
 }
@@ -1940,6 +2088,42 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf,
        return tty_write(file, buf, count, ppos);
 }
 
+void tty_port_init(struct tty_port *port)
+{
+       memset(port, 0, sizeof(*port));
+       init_waitqueue_head(&port->open_wait);
+       init_waitqueue_head(&port->close_wait);
+       mutex_init(&port->mutex);
+       port->close_delay = (50 * HZ) / 100;
+       port->closing_wait = (3000 * HZ) / 100;
+}
+EXPORT_SYMBOL(tty_port_init);
+
+int tty_port_alloc_xmit_buf(struct tty_port *port)
+{
+       /* We may sleep in get_zeroed_page() */
+       mutex_lock(&port->mutex);
+       if (port->xmit_buf == NULL)
+               port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
+       mutex_unlock(&port->mutex);
+       if (port->xmit_buf == NULL)
+               return -ENOMEM;
+       return 0;
+}
+EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
+
+void tty_port_free_xmit_buf(struct tty_port *port)
+{
+       mutex_lock(&port->mutex);
+       if (port->xmit_buf != NULL) {
+               free_page((unsigned long)port->xmit_buf);
+               port->xmit_buf = NULL;
+       }
+       mutex_unlock(&port->mutex);
+}
+EXPORT_SYMBOL(tty_port_free_xmit_buf);
+
+
 static char ptychar[] = "pqrstuvwxyzabcde";
 
 /**
@@ -2009,6 +2193,7 @@ static int init_dev(struct tty_driver *driver, int idx,
        struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
        struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
        int retval = 0;
+       struct tty_ldisc *ld;
 
        /* check whether we're reopening an existing tty */
        if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
@@ -2056,6 +2241,7 @@ static int init_dev(struct tty_driver *driver, int idx,
                goto fail_no_mem;
        initialize_tty_struct(tty);
        tty->driver = driver;
+       tty->ops = driver->ops;
        tty->index = idx;
        tty_line_name(driver, idx, tty->name);
 
@@ -2086,6 +2272,7 @@ static int init_dev(struct tty_driver *driver, int idx,
                        goto free_mem_out;
                initialize_tty_struct(o_tty);
                o_tty->driver = driver->other;
+               o_tty->ops = driver->ops;
                o_tty->index = idx;
                tty_line_name(driver->other, idx, o_tty->name);
 
@@ -2155,17 +2342,19 @@ static int init_dev(struct tty_driver *driver, int idx,
         * If we fail here just call release_tty to clean up.  No need
         * to decrement the use counts, as release_tty doesn't care.
         */
+        
+       ld = &tty->ldisc;
 
-       if (tty->ldisc.open) {
-               retval = (tty->ldisc.open)(tty);
+       if (ld->ops->open) {
+               retval = (ld->ops->open)(tty);
                if (retval)
                        goto release_mem_out;
        }
-       if (o_tty && o_tty->ldisc.open) {
-               retval = (o_tty->ldisc.open)(o_tty);
+       if (o_tty && o_tty->ldisc.ops->open) {
+               retval = (o_tty->ldisc.ops->open)(o_tty);
                if (retval) {
-                       if (tty->ldisc.close)
-                               (tty->ldisc.close)(tty);
+                       if (ld->ops->close)
+                               (ld->ops->close)(tty);
                        goto release_mem_out;
                }
                tty_ldisc_enable(o_tty);
@@ -2309,6 +2498,7 @@ static void release_tty(struct tty_struct *tty, int idx)
 static void release_dev(struct file *filp)
 {
        struct tty_struct *tty, *o_tty;
+       struct tty_ldisc ld;
        int     pty_master, tty_closing, o_tty_closing, do_sleep;
        int     devpts;
        int     idx;
@@ -2390,8 +2580,8 @@ static void release_dev(struct file *filp)
                }
        }
 #endif
-       if (tty->driver->close)
-               tty->driver->close(tty, filp);
+       if (tty->ops->close)
+               tty->ops->close(tty, filp);
 
        /*
         * Sanity check: if tty->count is going to zero, there shouldn't be
@@ -2542,26 +2732,27 @@ static void release_dev(struct file *filp)
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
        /*
         * Shutdown the current line discipline, and reset it to N_TTY.
-        * N.B. why reset ldisc when we're releasing the memory??
         *
         * FIXME: this MUST get fixed for the new reflocking
         */
-       if (tty->ldisc.close)
-               (tty->ldisc.close)(tty);
-       tty_ldisc_put(tty->ldisc.num);
+       if (tty->ldisc.ops->close)
+               (tty->ldisc.ops->close)(tty);
+       tty_ldisc_put(tty->ldisc.ops);
 
        /*
         *      Switch the line discipline back
         */
-       tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
+       WARN_ON(tty_ldisc_get(N_TTY, &ld));
+       tty_ldisc_assign(tty, &ld);
        tty_set_termios_ldisc(tty, N_TTY);
        if (o_tty) {
                /* FIXME: could o_tty be in setldisc here ? */
                clear_bit(TTY_LDISC, &o_tty->flags);
-               if (o_tty->ldisc.close)
-                       (o_tty->ldisc.close)(o_tty);
-               tty_ldisc_put(o_tty->ldisc.num);
-               tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY));
+               if (o_tty->ldisc.ops->close)
+                       (o_tty->ldisc.ops->close)(o_tty);
+               tty_ldisc_put(o_tty->ldisc.ops);
+               WARN_ON(tty_ldisc_get(N_TTY, &ld));
+               tty_ldisc_assign(o_tty, &ld);
                tty_set_termios_ldisc(o_tty, N_TTY);
        }
        /*
@@ -2570,15 +2761,9 @@ static void release_dev(struct file *filp)
         */
        release_tty(tty, idx);
 
-#ifdef CONFIG_UNIX98_PTYS
        /* Make this pty number available for reallocation */
-       if (devpts) {
-               mutex_lock(&allocated_ptys_lock);
-               idr_remove(&allocated_ptys, idx);
-               mutex_unlock(&allocated_ptys_lock);
-       }
-#endif
-
+       if (devpts)
+               devpts_kill_index(idx);
 }
 
 /**
@@ -2602,7 +2787,7 @@ static void release_dev(struct file *filp)
  *              ->siglock protects ->signal/->sighand
  */
 
-static int tty_open(struct inode *inode, struct file *filp)
+static int __tty_open(struct inode *inode, struct file *filp)
 {
        struct tty_struct *tty;
        int noctty, retval;
@@ -2674,8 +2859,8 @@ got_driver:
        printk(KERN_DEBUG "opening %s...", tty->name);
 #endif
        if (!retval) {
-               if (tty->driver->open)
-                       retval = tty->driver->open(tty, filp);
+               if (tty->ops->open)
+                       retval = tty->ops->open(tty, filp);
                else
                        retval = -ENODEV;
        }
@@ -2713,10 +2898,22 @@ got_driver:
                __proc_set_tty(current, tty);
        spin_unlock_irq(&current->sighand->siglock);
        mutex_unlock(&tty_mutex);
-       tty_audit_opening();
        return 0;
 }
 
+/* BKL pushdown: scary code avoidance wrapper */
+static int tty_open(struct inode *inode, struct file *filp)
+{
+       int ret;
+
+       lock_kernel();
+       ret = __tty_open(inode, filp);
+       unlock_kernel();
+       return ret;
+}
+
+
+
 #ifdef CONFIG_UNIX98_PTYS
 /**
  *     ptmx_open               -       open a unix 98 pty master
@@ -2730,34 +2927,18 @@ got_driver:
  *             allocated_ptys_lock handles the list of free pty numbers
  */
 
-static int ptmx_open(struct inode *inode, struct file *filp)
+static int __ptmx_open(struct inode *inode, struct file *filp)
 {
        struct tty_struct *tty;
        int retval;
        int index;
-       int idr_ret;
 
        nonseekable_open(inode, filp);
 
        /* find a device that is not in use. */
-       mutex_lock(&allocated_ptys_lock);
-       if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
-               mutex_unlock(&allocated_ptys_lock);
-               return -ENOMEM;
-       }
-       idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
-       if (idr_ret < 0) {
-               mutex_unlock(&allocated_ptys_lock);
-               if (idr_ret == -EAGAIN)
-                       return -ENOMEM;
-               return -EIO;
-       }
-       if (index >= pty_limit) {
-               idr_remove(&allocated_ptys, index);
-               mutex_unlock(&allocated_ptys_lock);
-               return -EIO;
-       }
-       mutex_unlock(&allocated_ptys_lock);
+       index = devpts_new_index();
+       if (index < 0)
+               return index;
 
        mutex_lock(&tty_mutex);
        retval = init_dev(ptm_driver, index, &tty);
@@ -2770,25 +2951,31 @@ static int ptmx_open(struct inode *inode, struct file *filp)
        filp->private_data = tty;
        file_move(filp, &tty->tty_files);
 
-       retval = -ENOMEM;
-       if (devpts_pty_new(tty->link))
+       retval = devpts_pty_new(tty->link);
+       if (retval)
                goto out1;
 
-       check_tty_count(tty, "tty_open");
-       retval = ptm_driver->open(tty, filp);
-       if (!retval) {
-               tty_audit_opening();
+       check_tty_count(tty, "ptmx_open");
+       retval = ptm_driver->ops->open(tty, filp);
+       if (!retval)
                return 0;
-       }
 out1:
        release_dev(filp);
        return retval;
 out:
-       mutex_lock(&allocated_ptys_lock);
-       idr_remove(&allocated_ptys, index);
-       mutex_unlock(&allocated_ptys_lock);
+       devpts_kill_index(index);
        return retval;
 }
+
+static int ptmx_open(struct inode *inode, struct file *filp)
+{
+       int ret;
+
+       lock_kernel();
+       ret = __ptmx_open(inode, filp);
+       unlock_kernel();
+       return ret;
+}
 #endif
 
 /**
@@ -2834,8 +3021,8 @@ static unsigned int tty_poll(struct file *filp, poll_table *wait)
                return 0;
 
        ld = tty_ldisc_ref_wait(tty);
-       if (ld->poll)
-               ret = (ld->poll)(tty, filp, wait);
+       if (ld->ops->poll)
+               ret = (ld->ops->poll)(tty, filp, wait);
        tty_ldisc_deref(ld);
        return ret;
 }
@@ -2843,21 +3030,24 @@ static unsigned int tty_poll(struct file *filp, poll_table *wait)
 static int tty_fasync(int fd, struct file *filp, int on)
 {
        struct tty_struct *tty;
-       int retval;
+       unsigned long flags;
+       int retval = 0;
 
+       lock_kernel();
        tty = (struct tty_struct *)filp->private_data;
        if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
-               return 0;
+               goto out;
 
        retval = fasync_helper(fd, filp, on, &tty->fasync);
        if (retval <= 0)
-               return retval;
+               goto out;
 
        if (on) {
                enum pid_type type;
                struct pid *pid;
                if (!waitqueue_active(&tty->read_wait))
                        tty->minimum_to_wake = 1;
+               spin_lock_irqsave(&tty->ctrl_lock, flags);
                if (tty->pgrp) {
                        pid = tty->pgrp;
                        type = PIDTYPE_PGID;
@@ -2865,14 +3055,18 @@ static int tty_fasync(int fd, struct file *filp, int on)
                        pid = task_pid(current);
                        type = PIDTYPE_PID;
                }
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                retval = __f_setown(filp, pid, type, 0);
                if (retval)
-                       return retval;
+                       goto out;
        } else {
                if (!tty->fasync && !waitqueue_active(&tty->read_wait))
                        tty->minimum_to_wake = N_TTY_BUF_SIZE;
        }
-       return 0;
+       retval = 0;
+out:
+       unlock_kernel();
+       return retval;
 }
 
 /**
@@ -2902,7 +3096,7 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
        if (get_user(ch, p))
                return -EFAULT;
        ld = tty_ldisc_ref_wait(tty);
-       ld->receive_buf(tty, &ch, &mbz, 1);
+       ld->ops->receive_buf(tty, &ch, &mbz, 1);
        tty_ldisc_deref(ld);
        return 0;
 }
@@ -2950,6 +3144,8 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
        struct winsize __user *arg)
 {
        struct winsize tmp_ws;
+       struct pid *pgrp, *rpgrp;
+       unsigned long flags;
 
        if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
                return -EFAULT;
@@ -2967,10 +3163,21 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
                }
        }
 #endif
-       if (tty->pgrp)
-               kill_pgrp(tty->pgrp, SIGWINCH, 1);
-       if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp)
-               kill_pgrp(real_tty->pgrp, SIGWINCH, 1);
+       /* Get the PID values and reference them so we can
+          avoid holding the tty ctrl lock while sending signals */
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
+       pgrp = get_pid(tty->pgrp);
+       rpgrp = get_pid(real_tty->pgrp);
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+       if (pgrp)
+               kill_pgrp(pgrp, SIGWINCH, 1);
+       if (rpgrp != pgrp && rpgrp)
+               kill_pgrp(rpgrp, SIGWINCH, 1);
+
+       put_pid(pgrp);
+       put_pid(rpgrp);
+
        tty->winsize = tmp_ws;
        real_tty->winsize = tmp_ws;
 done:
@@ -3031,10 +3238,13 @@ static int fionbio(struct file *file, int __user *p)
        if (get_user(nonblock, p))
                return -EFAULT;
 
+       /* file->f_flags is still BKL protected in the fs layer - vomit */
+       lock_kernel();
        if (nonblock)
                file->f_flags |= O_NONBLOCK;
        else
                file->f_flags &= ~O_NONBLOCK;
+       unlock_kernel();
        return 0;
 }
 
@@ -3092,6 +3302,27 @@ unlock:
 }
 
 /**
+ *     tty_get_pgrp    -       return a ref counted pgrp pid
+ *     @tty: tty to read
+ *
+ *     Returns a refcounted instance of the pid struct for the process
+ *     group controlling the tty.
+ */
+
+struct pid *tty_get_pgrp(struct tty_struct *tty)
+{
+       unsigned long flags;
+       struct pid *pgrp;
+
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
+       pgrp = get_pid(tty->pgrp);
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+       return pgrp;
+}
+EXPORT_SYMBOL_GPL(tty_get_pgrp);
+
+/**
  *     tiocgpgrp               -       get process group
  *     @tty: tty passed by user
  *     @real_tty: tty side of the tty pased by the user if a pty else the tty
@@ -3105,13 +3336,18 @@ unlock:
 
 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
 {
+       struct pid *pid;
+       int ret;
        /*
         * (tty == real_tty) is a cheap way of
         * testing if the tty is NOT a master pty.
         */
        if (tty == real_tty && current->signal->tty != real_tty)
                return -ENOTTY;
-       return put_user(pid_vnr(real_tty->pgrp), p);
+       pid = tty_get_pgrp(real_tty);
+       ret =  put_user(pid_vnr(pid), p);
+       put_pid(pid);
+       return ret;
 }
 
 /**
@@ -3123,7 +3359,7 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
  *     Set the process group of the tty to the session passed. Only
  *     permitted where the tty session is our session.
  *
- *     Locking: None
+ *     Locking: RCU, ctrl lock
  */
 
 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -3131,6 +3367,7 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
        struct pid *pgrp;
        pid_t pgrp_nr;
        int retval = tty_check_change(real_tty);
+       unsigned long flags;
 
        if (retval == -EIO)
                return -ENOTTY;
@@ -3153,8 +3390,10 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
        if (session_of_pgrp(pgrp) != task_session(current))
                goto out_unlock;
        retval = 0;
+       spin_lock_irqsave(&tty->ctrl_lock, flags);
        put_pid(real_tty->pgrp);
        real_tty->pgrp = get_pid(pgrp);
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 out_unlock:
        rcu_read_unlock();
        return retval;
@@ -3198,10 +3437,16 @@ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t _
 static int tiocsetd(struct tty_struct *tty, int __user *p)
 {
        int ldisc;
+       int ret;
 
        if (get_user(ldisc, p))
                return -EFAULT;
-       return tty_set_ldisc(tty, ldisc);
+
+       lock_kernel();
+       ret = tty_set_ldisc(tty, ldisc);
+       unlock_kernel();
+
+       return ret;
 }
 
 /**
@@ -3221,10 +3466,10 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
 {
        if (tty_write_lock(tty, 0) < 0)
                return -EINTR;
-       tty->driver->break_ctl(tty, -1);
+       tty->ops->break_ctl(tty, -1);
        if (!signal_pending(current))
                msleep_interruptible(duration);
-       tty->driver->break_ctl(tty, 0);
+       tty->ops->break_ctl(tty, 0);
        tty_write_unlock(tty);
        if (signal_pending(current))
                return -EINTR;
@@ -3232,7 +3477,7 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
 }
 
 /**
- *     tiocmget                -       get modem status
+ *     tty_tiocmget            -       get modem status
  *     @tty: tty device
  *     @file: user file pointer
  *     @p: pointer to result
@@ -3247,8 +3492,8 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
 {
        int retval = -EINVAL;
 
-       if (tty->driver->tiocmget) {
-               retval = tty->driver->tiocmget(tty, file);
+       if (tty->ops->tiocmget) {
+               retval = tty->ops->tiocmget(tty, file);
 
                if (retval >= 0)
                        retval = put_user(retval, p);
@@ -3257,7 +3502,7 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
 }
 
 /**
- *     tiocmset                -       set modem status
+ *     tty_tiocmset            -       set modem status
  *     @tty: tty device
  *     @file: user file pointer
  *     @cmd: command - clear bits, set bits or set all
@@ -3272,54 +3517,48 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
             unsigned __user *p)
 {
-       int retval = -EINVAL;
-
-       if (tty->driver->tiocmset) {
-               unsigned int set, clear, val;
-
-               retval = get_user(val, p);
-               if (retval)
-                       return retval;
-
-               set = clear = 0;
-               switch (cmd) {
-               case TIOCMBIS:
-                       set = val;
-                       break;
-               case TIOCMBIC:
-                       clear = val;
-                       break;
-               case TIOCMSET:
-                       set = val;
-                       clear = ~val;
-                       break;
-               }
+       int retval;
+       unsigned int set, clear, val;
 
-               set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
-               clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
+       if (tty->ops->tiocmset == NULL)
+               return -EINVAL;
 
-               retval = tty->driver->tiocmset(tty, file, set, clear);
+       retval = get_user(val, p);
+       if (retval)
+               return retval;
+       set = clear = 0;
+       switch (cmd) {
+       case TIOCMBIS:
+               set = val;
+               break;
+       case TIOCMBIC:
+               clear = val;
+               break;
+       case TIOCMSET:
+               set = val;
+               clear = ~val;
+               break;
        }
-       return retval;
+       set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
+       clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
+       return tty->ops->tiocmset(tty, file, set, clear);
 }
 
 /*
  * Split this up, as gcc can choke on it otherwise..
  */
-int tty_ioctl(struct inode *inode, struct file *file,
-             unsigned int cmd, unsigned long arg)
+long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        struct tty_struct *tty, *real_tty;
        void __user *p = (void __user *)arg;
        int retval;
        struct tty_ldisc *ld;
+       struct inode *inode = file->f_dentry->d_inode;
 
        tty = (struct tty_struct *)file->private_data;
        if (tty_paranoia_check(tty, inode, "tty_ioctl"))
                return -EINVAL;
 
-       /* CHECKME: is this safe as one end closes ? */
-
        real_tty = tty;
        if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
            tty->driver->subtype == PTY_TYPE_MASTER)
@@ -3328,21 +3567,28 @@ int tty_ioctl(struct inode *inode, struct file *file,
        /*
         * Break handling by driver
         */
-       if (!tty->driver->break_ctl) {
+
+       retval = -EINVAL;
+
+       if (!tty->ops->break_ctl) {
                switch (cmd) {
                case TIOCSBRK:
                case TIOCCBRK:
-                       if (tty->driver->ioctl)
-                               return tty->driver->ioctl(tty, file, cmd, arg);
-                       return -EINVAL;
+                       if (tty->ops->ioctl)
+                               retval = tty->ops->ioctl(tty, file, cmd, arg);
+                       if (retval != -EINVAL && retval != -ENOIOCTLCMD)
+                               printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
+                       return retval;
 
                /* These two ioctl's always return success; even if */
                /* the driver doesn't support them. */
                case TCSBRK:
                case TCSBRKP:
-                       if (!tty->driver->ioctl)
+                       if (!tty->ops->ioctl)
                                return 0;
-                       retval = tty->driver->ioctl(tty, file, cmd, arg);
+                       retval = tty->ops->ioctl(tty, file, cmd, arg);
+                       if (retval != -EINVAL && retval != -ENOIOCTLCMD)
+                               printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
                        if (retval == -ENOIOCTLCMD)
                                retval = 0;
                        return retval;
@@ -3400,8 +3646,7 @@ int tty_ioctl(struct inode *inode, struct file *file,
        case TIOCGSID:
                return tiocgsid(tty, real_tty, p);
        case TIOCGETD:
-               /* FIXME: check this is ok */
-               return put_user(tty->ldisc.num, (int __user *)p);
+               return put_user(tty->ldisc.ops->num, (int __user *)p);
        case TIOCSETD:
                return tiocsetd(tty, p);
 #ifdef CONFIG_VT
@@ -3412,11 +3657,13 @@ int tty_ioctl(struct inode *inode, struct file *file,
         * Break handling
         */
        case TIOCSBRK:  /* Turn break on, unconditionally */
-               tty->driver->break_ctl(tty, -1);
+               if (tty->ops->break_ctl)
+                       tty->ops->break_ctl(tty, -1);
                return 0;
 
        case TIOCCBRK:  /* Turn break off, unconditionally */
-               tty->driver->break_ctl(tty, 0);
+               if (tty->ops->break_ctl)
+                       tty->ops->break_ctl(tty, 0);
                return 0;
        case TCSBRK:   /* SVID version: non-zero arg --> no break */
                /* non-zero arg means wait for all output data
@@ -3445,15 +3692,15 @@ int tty_ioctl(struct inode *inode, struct file *file,
                }
                break;
        }
-       if (tty->driver->ioctl) {
-               retval = (tty->driver->ioctl)(tty, file, cmd, arg);
+       if (tty->ops->ioctl) {
+               retval = (tty->ops->ioctl)(tty, file, cmd, arg);
                if (retval != -ENOIOCTLCMD)
                        return retval;
        }
        ld = tty_ldisc_ref_wait(tty);
        retval = -EINVAL;
-       if (ld->ioctl) {
-               retval = ld->ioctl(tty, file, cmd, arg);
+       if (ld->ops->ioctl) {
+               retval = ld->ops->ioctl(tty, file, cmd, arg);
                if (retval == -ENOIOCTLCMD)
                        retval = -EINVAL;
        }
@@ -3473,15 +3720,15 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
        if (tty_paranoia_check(tty, inode, "tty_ioctl"))
                return -EINVAL;
 
-       if (tty->driver->compat_ioctl) {
-               retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg);
+       if (tty->ops->compat_ioctl) {
+               retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
                if (retval != -ENOIOCTLCMD)
                        return retval;
        }
 
        ld = tty_ldisc_ref_wait(tty);
-       if (ld->compat_ioctl)
-               retval = ld->compat_ioctl(tty, file, cmd, arg);
+       if (ld->ops->compat_ioctl)
+               retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
        tty_ldisc_deref(ld);
 
        return retval;
@@ -3524,8 +3771,7 @@ void __do_SAK(struct tty_struct *tty)
 
        tty_ldisc_flush(tty);
 
-       if (tty->driver->flush_buffer)
-               tty->driver->flush_buffer(tty);
+       tty_driver_flush_buffer(tty);
 
        read_lock(&tasklist_lock);
        /* Kill the entire session */
@@ -3654,7 +3900,8 @@ static void flush_to_ldisc(struct work_struct *work)
                        flag_buf = head->flag_buf_ptr + head->read;
                        head->read += count;
                        spin_unlock_irqrestore(&tty->buf.lock, flags);
-                       disc->receive_buf(tty, char_buf, flag_buf, count);
+                       disc->ops->receive_buf(tty, char_buf,
+                                                       flag_buf, count);
                        spin_lock_irqsave(&tty->buf.lock, flags);
                }
                /* Restore the queue head */
@@ -3715,9 +3962,12 @@ EXPORT_SYMBOL(tty_flip_buffer_push);
 
 static void initialize_tty_struct(struct tty_struct *tty)
 {
+       struct tty_ldisc ld;
        memset(tty, 0, sizeof(struct tty_struct));
        tty->magic = TTY_MAGIC;
-       tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
+       if (tty_ldisc_get(N_TTY, &ld) < 0)
+               panic("n_tty: init_tty");
+       tty_ldisc_assign(tty, &ld);
        tty->session = NULL;
        tty->pgrp = NULL;
        tty->overrun_time = jiffies;
@@ -3731,19 +3981,32 @@ static void initialize_tty_struct(struct tty_struct *tty)
        mutex_init(&tty->atomic_read_lock);
        mutex_init(&tty->atomic_write_lock);
        spin_lock_init(&tty->read_lock);
+       spin_lock_init(&tty->ctrl_lock);
        INIT_LIST_HEAD(&tty->tty_files);
        INIT_WORK(&tty->SAK_work, do_SAK_work);
 }
 
-/*
- * The default put_char routine if the driver did not define one.
+/**
+ *     tty_put_char    -       write one character to a tty
+ *     @tty: tty
+ *     @ch: character
+ *
+ *     Write one byte to the tty using the provided put_char method
+ *     if present. Returns the number of characters successfully output.
+ *
+ *     Note: the specific put_char operation in the driver layer may go
+ *     away soon. Don't call it directly, use this method
  */
 
-static void tty_default_put_char(struct tty_struct *tty, unsigned char ch)
+int tty_put_char(struct tty_struct *tty, unsigned char ch)
 {
-       tty->driver->write(tty, &ch, 1);
+       if (tty->ops->put_char)
+               return tty->ops->put_char(tty, ch);
+       return tty->ops->write(tty, &ch, 1);
 }
 
+EXPORT_SYMBOL_GPL(tty_put_char);
+
 static struct class *tty_class;
 
 /**
@@ -3782,7 +4045,7 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index,
        else
                tty_line_name(driver, index, name);
 
-       return device_create(tty_class, device, dev, name);
+       return device_create_drvdata(tty_class, device, dev, NULL, name);
 }
 
 /**
@@ -3826,32 +4089,8 @@ void put_tty_driver(struct tty_driver *driver)
 void tty_set_operations(struct tty_driver *driver,
                        const struct tty_operations *op)
 {
-       driver->open = op->open;
-       driver->close = op->close;
-       driver->write = op->write;
-       driver->put_char = op->put_char;
-       driver->flush_chars = op->flush_chars;
-       driver->write_room = op->write_room;
-       driver->chars_in_buffer = op->chars_in_buffer;
-       driver->ioctl = op->ioctl;
-       driver->compat_ioctl = op->compat_ioctl;
-       driver->set_termios = op->set_termios;
-       driver->throttle = op->throttle;
-       driver->unthrottle = op->unthrottle;
-       driver->stop = op->stop;
-       driver->start = op->start;
-       driver->hangup = op->hangup;
-       driver->break_ctl = op->break_ctl;
-       driver->flush_buffer = op->flush_buffer;
-       driver->set_ldisc = op->set_ldisc;
-       driver->wait_until_sent = op->wait_until_sent;
-       driver->send_xchar = op->send_xchar;
-       driver->read_proc = op->read_proc;
-       driver->write_proc = op->write_proc;
-       driver->tiocmget = op->tiocmget;
-       driver->tiocmset = op->tiocmset;
-}
-
+       driver->ops = op;
+};
 
 EXPORT_SYMBOL(alloc_tty_driver);
 EXPORT_SYMBOL(put_tty_driver);
@@ -3914,9 +4153,6 @@ int tty_register_driver(struct tty_driver *driver)
                return error;
        }
 
-       if (!driver->put_char)
-               driver->put_char = tty_default_put_char;
-
        mutex_lock(&tty_mutex);
        list_add(&driver->tty_drivers, &tty_drivers);
        mutex_unlock(&tty_mutex);
@@ -3992,14 +4228,19 @@ void proc_clear_tty(struct task_struct *p)
 }
 EXPORT_SYMBOL(proc_clear_tty);
 
+/* Called under the sighand lock */
+
 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
 {
        if (tty) {
-               /* We should not have a session or pgrp to here but.... */
+               unsigned long flags;
+               /* We should not have a session or pgrp to put here but.... */
+               spin_lock_irqsave(&tty->ctrl_lock, flags);
                put_pid(tty->session);
                put_pid(tty->pgrp);
-               tty->session = get_pid(task_session(tsk));
                tty->pgrp = get_pid(task_pgrp(tsk));
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+               tty->session = get_pid(task_session(tsk));
        }
        put_pid(tsk->signal->tty_old_pgrp);
        tsk->signal->tty = tty;
@@ -4082,20 +4323,22 @@ static int __init tty_init(void)
        if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
            register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
                panic("Couldn't register /dev/tty driver\n");
-       device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty");
+       device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
+                             "tty");
 
        cdev_init(&console_cdev, &console_fops);
        if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
            register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
                panic("Couldn't register /dev/console driver\n");
-       device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console");
+       device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
+                             "console");
 
 #ifdef CONFIG_UNIX98_PTYS
        cdev_init(&ptmx_cdev, &ptmx_fops);
        if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
            register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
                panic("Couldn't register /dev/ptmx driver\n");
-       device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx");
+       device_create_drvdata(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 #endif
 
 #ifdef CONFIG_VT
@@ -4103,7 +4346,7 @@ static int __init tty_init(void)
        if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
            register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
                panic("Couldn't register /dev/tty0 driver\n");
-       device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0");
+       device_create_drvdata(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
 
        vty_init();
 #endif