1 files changed, 266 insertions, 275 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index bb0d9199e994..4044c864fdd4 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -109,13 +109,15 @@
 #define TTY_PARANOIA_CHECK 1
 #define CHECK_TTY_COUNT 1
 
-struct termios tty_std_termios = {      /* for the benefit of tty drivers  */
+struct ktermios tty_std_termios = {     /* for the benefit of tty drivers  */
         .c_iflag = ICRNL | IXON,
         .c_oflag = OPOST | ONLCR,
         .c_cflag = B38400 | CS8 | CREAD | HUPCL,
         .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
                    ECHOCTL | ECHOKE | IEXTEN,
-        .c_cc = INIT_C_CC
+        .c_cc = INIT_C_CC,
+        .c_ispeed = 38400,
+        .c_ospeed = 38400
 };
 
 EXPORT_SYMBOL(tty_std_termios);
@@ -126,9 +128,10 @@ EXPORT_SYMBOL(tty_std_termios);
    
 LIST_HEAD(tty_drivers);                 /* linked list of tty drivers */
 
-/* Semaphore to protect creating and releasing a tty. This is shared with
+/* Mutex to protect creating and releasing a tty. This is shared with
    vt.c for deeply disgusting hack reasons */
 DEFINE_MUTEX(tty_mutex);
+EXPORT_SYMBOL(tty_mutex);
 
 #ifdef CONFIG_UNIX98_PTYS
 extern struct tty_driver *ptm_driver;   /* Unix98 pty masters; for /dev/ptmx */
@@ -160,17 +163,11 @@ static void release_mem(struct tty_struct *tty, int idx);
  *      been initialized in any way but has been zeroed
  *
  *      Locking: none
- *      FIXME: use kzalloc
  */
 
 static struct tty_struct *alloc_tty_struct(void)
 {
-        struct tty_struct *tty;
-
-        tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL);
-        if (tty)
-                memset(tty, 0, sizeof(struct tty_struct));
-        return tty;
+        return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
 }
 
 static void tty_buffer_free_all(struct tty_struct *);
@@ -255,7 +252,7 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
                                     "!= #fd's(%d) in %s\n",
                        tty->name, tty->count, count, routine);
                 return count;
-       }        
+        }
 #endif
         return 0;
 }
@@ -264,18 +261,6 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
  * Tty buffer allocation management
  */
 
-
-/**
- *      tty_buffer_free_all             -       free buffers used by a tty
- *      @tty: tty to free from
- *
- *      Remove all the buffers pending on a tty whether queued with data
- *      or in the free ring. Must be called when the tty is no longer in use
- *
- *      Locking: none
- */
-
-
 /**
  *      tty_buffer_free_all             -       free buffers used by a tty
  *      @tty: tty to free from
@@ -483,10 +468,9 @@ int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars,
                 tb->used += space;
                 copied += space;
                 chars += space;
-        }
-        /* There is a small chance that we need to split the data over
-           several buffers. If this is the case we must loop */
-        while (unlikely(size > copied));
+                /* There is a small chance that we need to split the data over
+                   several buffers. If this is the case we must loop */
+        } while (unlikely(size > copied));
         return copied;
 }
 EXPORT_SYMBOL(tty_insert_flip_string);
@@ -521,10 +505,9 @@ int tty_insert_flip_string_flags(struct tty_struct *tty,
                 copied += space;
                 chars += space;
                 flags += space;
-        }
-        /* There is a small chance that we need to split the data over
-           several buffers. If this is the case we must loop */
-        while (unlikely(size > copied));
+                /* There is a small chance that we need to split the data over
+                   several buffers. If this is the case we must loop */
+        } while (unlikely(size > copied));
         return copied;
 }
 EXPORT_SYMBOL(tty_insert_flip_string_flags);
@@ -621,14 +604,14 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
  *      they are not on hot paths so a little discipline won't do 
  *      any harm.
  *
- *      Locking: takes termios_sem
+ *      Locking: takes termios_mutex
  */
  
 static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 {
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
         tty->termios->c_line = num;
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
 }
 
 /*
@@ -922,7 +905,7 @@ static void tty_ldisc_enable(struct tty_struct *tty)
  *      context.
  *
  *      Locking: takes tty_ldisc_lock.
- *              called functions take termios_sem
+ *               called functions take termios_mutex
  */
  
 static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
@@ -1258,10 +1241,26 @@ void tty_ldisc_flush(struct tty_struct *tty)
 }
 
 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
+
+/**
+ *      tty_reset_termios       -       reset terminal state
+ *      @tty: tty to reset
+ *
+ *      Restore a terminal to the driver default state
+ */
+
+static void tty_reset_termios(struct tty_struct *tty)
+{
+        mutex_lock(&tty->termios_mutex);
+        *tty->termios = tty->driver->init_termios;
+        tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
+        tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
+        mutex_unlock(&tty->termios_mutex);
+}
         
 /**
  *      do_tty_hangup           -       actual handler for hangup events
- *      @data: tty device
+ *      @work: tty device
  *
  *      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
@@ -1274,16 +1273,17 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
  *
  *      Locking:
  *              BKL
- *              redirect lock for undoing redirection
- *              file list lock for manipulating list of ttys
- *              tty_ldisc_lock from called functions
- *              termios_sem resetting termios data
- *              tasklist_lock to walk task list for hangup event
- *
+ *                redirect lock for undoing redirection
+ *                file list lock for manipulating list of ttys
+ *                tty_ldisc_lock from called functions
+ *                termios_mutex resetting termios data
+ *                tasklist_lock to walk task list for hangup event
+ *                  ->siglock to protect ->signal/->sighand
  */
-static void do_tty_hangup(void *data)
+static void do_tty_hangup(struct work_struct *work)
 {
-        struct tty_struct *tty = (struct tty_struct *) data;
+        struct tty_struct *tty =
+                container_of(work, struct tty_struct, hangup_work);
         struct file * cons_filp = NULL;
         struct file *filp, *f = NULL;
         struct task_struct *p;
@@ -1345,11 +1345,7 @@ static void do_tty_hangup(void *data)
          * N_TTY.
          */
         if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
-        {
-                down(&tty->termios_sem);
-                *tty->termios = tty->driver->init_termios;
-                up(&tty->termios_sem);
-        }
+                tty_reset_termios(tty);
         
         /* Defer ldisc switch */
         /* tty_deferred_ldisc_switch(N_TTY);
@@ -1360,14 +1356,18 @@ static void do_tty_hangup(void *data)
         read_lock(&tasklist_lock);
         if (tty->session > 0) {
                 do_each_task_pid(tty->session, PIDTYPE_SID, p) {
+                        spin_lock_irq(&p->sighand->siglock);
                         if (p->signal->tty == tty)
                                 p->signal->tty = NULL;
-                        if (!p->signal->leader)
+                        if (!p->signal->leader) {
+                                spin_unlock_irq(&p->sighand->siglock);
                                 continue;
-                        group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
-                        group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
+                        }
+                        __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
+                        __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
                         if (tty->pgrp > 0)
                                 p->signal->tty_old_pgrp = tty->pgrp;
+                        spin_unlock_irq(&p->sighand->siglock);
                 } while_each_task_pid(tty->session, PIDTYPE_SID, p);
         }
         read_unlock(&tasklist_lock);
@@ -1440,7 +1440,7 @@ void tty_vhangup(struct tty_struct * tty)
 
         printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
 #endif
-        do_tty_hangup((void *) tty);
+        do_tty_hangup(&tty->hangup_work);
 }
 EXPORT_SYMBOL(tty_vhangup);
 
@@ -1459,6 +1459,14 @@ int tty_hung_up_p(struct file * filp)
 
 EXPORT_SYMBOL(tty_hung_up_p);
 
+static void session_clear_tty(pid_t session)
+{
+        struct task_struct *p;
+        do_each_task_pid(session, PIDTYPE_SID, p) {
+                proc_clear_tty(p);
+        } while_each_task_pid(session, PIDTYPE_SID, p);
+}
+
 /**
  *      disassociate_ctty       -       disconnect controlling tty
  *      @on_exit: true if exiting so need to "hang up" the session
@@ -1475,31 +1483,35 @@ EXPORT_SYMBOL(tty_hung_up_p);
  *      The argument on_exit is set to 1 if called when a process is
  *      exiting; it is 0 if called by the ioctl TIOCNOTTY.
  *
- *      Locking: tty_mutex is taken to protect current->signal->tty
+ *      Locking:
  *              BKL is taken for hysterical raisins
- *              Tasklist lock is taken (under tty_mutex) to walk process
- *              lists for the session.
+ *                tty_mutex is taken to protect tty
+ *                ->siglock is taken to protect ->signal/->sighand
+ *                tasklist_lock is taken to walk process list for sessions
+ *                  ->siglock is taken to protect ->signal/->sighand
  */
 
 void disassociate_ctty(int on_exit)
 {
         struct tty_struct *tty;
-        struct task_struct *p;
         int tty_pgrp = -1;
+        int session;
 
         lock_kernel();
 
         mutex_lock(&tty_mutex);
-        tty = current->signal->tty;
+        tty = get_current_tty();
         if (tty) {
                 tty_pgrp = tty->pgrp;
                 mutex_unlock(&tty_mutex);
+                /* XXX: here we race, there is nothing protecting tty */
                 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
                         tty_vhangup(tty);
         } else {
-                if (current->signal->tty_old_pgrp) {
-                        kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
-                        kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
+                pid_t old_pgrp = current->signal->tty_old_pgrp;
+                if (old_pgrp) {
+                        kill_pg(old_pgrp, SIGHUP, on_exit);
+                        kill_pg(old_pgrp, SIGCONT, on_exit);
                 }
                 mutex_unlock(&tty_mutex);
                 unlock_kernel();        
@@ -1511,19 +1523,29 @@ void disassociate_ctty(int on_exit)
                         kill_pg(tty_pgrp, SIGCONT, on_exit);
         }
 
-        /* Must lock changes to tty_old_pgrp */
-        mutex_lock(&tty_mutex);
+        spin_lock_irq(&current->sighand->siglock);
         current->signal->tty_old_pgrp = 0;
-        tty->session = 0;
-        tty->pgrp = -1;
+        session = process_session(current);
+        spin_unlock_irq(&current->sighand->siglock);
+
+        mutex_lock(&tty_mutex);
+        /* It is possible that do_tty_hangup has free'd this tty */
+        tty = get_current_tty();
+        if (tty) {
+                tty->session = 0;
+                tty->pgrp = 0;
+        } else {
+#ifdef TTY_DEBUG_HANGUP
+                printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
+                       " = NULL", tty);
+#endif
+        }
+        mutex_unlock(&tty_mutex);
 
         /* Now clear signal->tty under the lock */
         read_lock(&tasklist_lock);
-        do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
-                p->signal->tty = NULL;
-        } while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
+        session_clear_tty(session);
         read_unlock(&tasklist_lock);
-        mutex_unlock(&tty_mutex);
         unlock_kernel();
 }
 
@@ -1621,7 +1643,7 @@ static ssize_t tty_read(struct file * file, char __user * buf, size_t count,
         struct tty_ldisc *ld;
 
         tty = (struct tty_struct *)file->private_data;
-        inode = file->f_dentry->d_inode;
+        inode = file->f_path.dentry->d_inode;
         if (tty_paranoia_check(tty, inode, "tty_read"))
                 return -EIO;
         if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
@@ -1724,7 +1746,7 @@ static inline ssize_t do_tty_write(
                 cond_resched();
         }
         if (written) {
-                struct inode *inode = file->f_dentry->d_inode;
+                struct inode *inode = file->f_path.dentry->d_inode;
                 inode->i_mtime = current_fs_time(inode->i_sb);
                 ret = written;
         }
@@ -1755,7 +1777,7 @@ static ssize_t tty_write(struct file * file, const char __user * buf, size_t cou
                          loff_t *ppos)
 {
         struct tty_struct * tty;
-        struct inode *inode = file->f_dentry->d_inode;
+        struct inode *inode = file->f_path.dentry->d_inode;
         ssize_t ret;
         struct tty_ldisc *ld;
         
@@ -1862,8 +1884,8 @@ static int init_dev(struct tty_driver *driver, int idx,
         struct tty_struct **ret_tty)
 {
         struct tty_struct *tty, *o_tty;
-        struct termios *tp, **tp_loc, *o_tp, **o_tp_loc;
-        struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
+        struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
+        struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
         int retval = 0;
 
         /* check whether we're reopening an existing tty */
@@ -1910,7 +1932,7 @@ static int init_dev(struct tty_driver *driver, int idx,
         }
 
         if (!*tp_loc) {
-                tp = (struct termios *) kmalloc(sizeof(struct termios),
+                tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
                                                 GFP_KERNEL);
                 if (!tp)
                         goto free_mem_out;
@@ -1918,11 +1940,11 @@ static int init_dev(struct tty_driver *driver, int idx,
         }
 
         if (!*ltp_loc) {
-                ltp = (struct termios *) kmalloc(sizeof(struct termios),
+                ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
                                                  GFP_KERNEL);
                 if (!ltp)
                         goto free_mem_out;
-                memset(ltp, 0, sizeof(struct termios));
+                memset(ltp, 0, sizeof(struct ktermios));
         }
 
         if (driver->type == TTY_DRIVER_TYPE_PTY) {
@@ -1943,19 +1965,19 @@ static int init_dev(struct tty_driver *driver, int idx,
                 }
 
                 if (!*o_tp_loc) {
-                        o_tp = (struct termios *)
-                                kmalloc(sizeof(struct termios), GFP_KERNEL);
+                        o_tp = (struct ktermios *)
+                                kmalloc(sizeof(struct ktermios), GFP_KERNEL);
                         if (!o_tp)
                                 goto free_mem_out;
                         *o_tp = driver->other->init_termios;
                 }
 
                 if (!*o_ltp_loc) {
-                        o_ltp = (struct termios *)
-                                kmalloc(sizeof(struct termios), GFP_KERNEL);
+                        o_ltp = (struct ktermios *)
+                                kmalloc(sizeof(struct ktermios), GFP_KERNEL);
                         if (!o_ltp)
                                 goto free_mem_out;
-                        memset(o_ltp, 0, sizeof(struct termios));
+                        memset(o_ltp, 0, sizeof(struct ktermios));
                 }
 
                 /*
@@ -1994,6 +2016,9 @@ static int init_dev(struct tty_driver *driver, int idx,
                 *ltp_loc = ltp;
         tty->termios = *tp_loc;
         tty->termios_locked = *ltp_loc;
+        /* Compatibility until drivers always set this */
+        tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
+        tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
         driver->refcount++;
         tty->count++;
 
@@ -2072,8 +2097,9 @@ fail_no_mem:
 
         /* call the tty release_mem routine to clean out this slot */
 release_mem_out:
-        printk(KERN_INFO "init_dev: ldisc open failed, "
-                         "clearing slot %d\n", idx);
+        if (printk_ratelimit())
+                printk(KERN_INFO "init_dev: ldisc open failed, "
+                                 "clearing slot %d\n", idx);
         release_mem(tty, idx);
         goto end_init;
 }
@@ -2095,7 +2121,7 @@ release_mem_out:
 static void release_mem(struct tty_struct *tty, int idx)
 {
         struct tty_struct *o_tty;
-        struct termios *tp;
+        struct ktermios *tp;
         int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM;
 
         if ((o_tty = tty->link) != NULL) {
@@ -2161,7 +2187,7 @@ static void release_dev(struct file * filp)
         unsigned long flags;
         
         tty = (struct tty_struct *)filp->private_data;
-        if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "release_dev"))
+        if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev"))
                 return;
 
         check_tty_count(tty, "release_dev");
@@ -2342,16 +2368,10 @@ static void release_dev(struct file * filp)
          * tty.
          */
         if (tty_closing || o_tty_closing) {
-                struct task_struct *p;
-
                 read_lock(&tasklist_lock);
-                do_each_task_pid(tty->session, PIDTYPE_SID, p) {
-                        p->signal->tty = NULL;
-                } while_each_task_pid(tty->session, PIDTYPE_SID, p);
+                session_clear_tty(tty->session);
                 if (o_tty)
-                        do_each_task_pid(o_tty->session, PIDTYPE_SID, p) {
-                                p->signal->tty = NULL;
-                        } while_each_task_pid(o_tty->session, PIDTYPE_SID, p);
+                        session_clear_tty(o_tty->session);
                 read_unlock(&tasklist_lock);
         }
 
@@ -2448,9 +2468,9 @@ static void release_dev(struct file * filp)
  *      The termios state of a pty is reset on first open so that
  *      settings don't persist across reuse.
  *
- *      Locking: tty_mutex protects current->signal->tty, get_tty_driver and
- *              init_dev work. tty->count should protect the rest.
- *              task_lock is held to update task details for sessions
+ *      Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
+ *               tty->count should protect the rest.
+ *               ->siglock protects ->signal/->sighand
  */
 
 static int tty_open(struct inode * inode, struct file * filp)
@@ -2472,12 +2492,13 @@ retry_open:
         mutex_lock(&tty_mutex);
 
         if (device == MKDEV(TTYAUX_MAJOR,0)) {
-                if (!current->signal->tty) {
+                tty = get_current_tty();
+                if (!tty) {
                         mutex_unlock(&tty_mutex);
                         return -ENXIO;
                 }
-                driver = current->signal->tty->driver;
-                index = current->signal->tty->index;
+                driver = tty->driver;
+                index = tty->index;
                 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
                 /* noctty = 1; */
                 goto got_driver;
@@ -2552,17 +2573,16 @@ got_driver:
                         filp->f_op = &tty_fops;
                 goto retry_open;
         }
+
+        mutex_lock(&tty_mutex);
+        spin_lock_irq(&current->sighand->siglock);
         if (!noctty &&
             current->signal->leader &&
             !current->signal->tty &&
-            tty->session == 0) {
-                task_lock(current);
-                current->signal->tty = tty;
-                task_unlock(current);
-                current->signal->tty_old_pgrp = 0;
-                tty->session = current->signal->session;
-                tty->pgrp = process_group(current);
-        }
+            tty->session == 0)
+                __proc_set_tty(current, tty);
+        spin_unlock_irq(&current->sighand->siglock);
+        mutex_unlock(&tty_mutex);
         return 0;
 }
 
@@ -2677,7 +2697,7 @@ static unsigned int tty_poll(struct file * filp, poll_table * wait)
         int ret = 0;
 
         tty = (struct tty_struct *)filp->private_data;
-        if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll"))
+        if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
                 return 0;
                 
         ld = tty_ldisc_ref_wait(tty);
@@ -2693,7 +2713,7 @@ static int tty_fasync(int fd, struct file * filp, int on)
         int retval;
 
         tty = (struct tty_struct *)filp->private_data;
-        if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_fasync"))
+        if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
                 return 0;
         
         retval = fasync_helper(fd, filp, on, &tty->fasync);
@@ -2726,6 +2746,8 @@ static int tty_fasync(int fd, struct file * filp, int on)
  *      Locking:
  *              Called functions take tty_ldisc_lock
  *              current->signal->tty check is safe without locks
+ *
+ *      FIXME: may race normal receive processing
  */
 
 static int tiocsti(struct tty_struct *tty, char __user *p)
@@ -2748,18 +2770,21 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
  *      @tty; tty
  *      @arg: user buffer for result
  *
- *      Copies the kernel idea of the window size into the user buffer. No
- *      locking is done.
+ *      Copies the kernel idea of the window size into the user buffer.
  *
- *      FIXME: Returning random values racing a window size set is wrong
- *      should lock here against that
+ *      Locking: tty->termios_mutex is taken to ensure the winsize data
+ *              is consistent.
  */
 
 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
 {
-        if (copy_to_user(arg, &tty->winsize, sizeof(*arg)))
-                return -EFAULT;
-        return 0;
+        int err;
+
+        mutex_lock(&tty->termios_mutex);
+        err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
+        mutex_unlock(&tty->termios_mutex);
+
+        return err ? -EFAULT: 0;
 }
 
 /**
@@ -2772,12 +2797,11 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
  *      actually has driver level meaning and triggers a VC resize.
  *
  *      Locking:
- *              The console_sem is used to ensure we do not try and resize
- *      the console twice at once.
- *      FIXME: Two racing size sets may leave the console and kernel
- *              parameters disagreeing. Is this exploitable ?
- *      FIXME: Random values racing a window size get is wrong
- *      should lock here against that
+ *              Called function use the console_sem is used to ensure we do
+ *      not try and resize the console twice at once.
+ *              The tty->termios_mutex is used to ensure we don't double
+ *      resize and get confused. Lock order - tty->termios_mutex before
+ *      console sem
  */
 
 static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
@@ -2787,17 +2811,18 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
 
         if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
                 return -EFAULT;
+
+        mutex_lock(&tty->termios_mutex);
         if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg)))
-                return 0;
+                goto done;
+
 #ifdef CONFIG_VT
         if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) {
-                int rc;
-
-                acquire_console_sem();
-                rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row);
-                release_console_sem();
-                if (rc)
-                        return -ENXIO;
+                if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col,
+                                        tmp_ws.ws_row)) {
+                        mutex_unlock(&tty->termios_mutex);
+                        return -ENXIO;
+                }
         }
 #endif
         if (tty->pgrp > 0)
@@ -2806,6 +2831,8 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
                 kill_pg(real_tty->pgrp, SIGWINCH, 1);
         tty->winsize = tmp_ws;
         real_tty->winsize = tmp_ws;
+done:
+        mutex_unlock(&tty->termios_mutex);
         return 0;
 }
 
@@ -2878,27 +2905,28 @@ static int fionbio(struct file *file, int __user *p)
  *      leader to set this tty as the controlling tty for the session.
  *
  *      Locking:
- *              Takes tasklist lock internally to walk sessions
- *              Takes task_lock() when updating signal->tty
- *
- *      FIXME: tty_mutex is needed to protect signal->tty references.
- *      FIXME: why task_lock on the signal->tty reference ??
- *
+ *              Takes tty_mutex() to protect tty instance
+ *              Takes tasklist_lock internally to walk sessions
+ *              Takes ->siglock() when updating signal->tty
  */
 
 static int tiocsctty(struct tty_struct *tty, int arg)
 {
-        struct task_struct *p;
-
+        int ret = 0;
         if (current->signal->leader &&
-            (current->signal->session == tty->session))
-                return 0;
+                        (process_session(current) == tty->session))
+                return ret;
+
+        mutex_lock(&tty_mutex);
         /*
          * The process must be a session leader and
          * not have a controlling tty already.
          */
-        if (!current->signal->leader || current->signal->tty)
-                return -EPERM;
+        if (!current->signal->leader || current->signal->tty) {
+                ret = -EPERM;
+                goto unlock;
+        }
+
         if (tty->session > 0) {
                 /*
                  * This tty is already the controlling
@@ -2908,22 +2936,18 @@ static int tiocsctty(struct tty_struct *tty, int arg)
                         /*
                          * Steal it away
                          */
-
                         read_lock(&tasklist_lock);
-                        do_each_task_pid(tty->session, PIDTYPE_SID, p) {
-                                p->signal->tty = NULL;
-                        } while_each_task_pid(tty->session, PIDTYPE_SID, p);
+                        session_clear_tty(tty->session);
                         read_unlock(&tasklist_lock);
-                } else
-                        return -EPERM;
+                } else {
+                        ret = -EPERM;
+                        goto unlock;
+                }
         }
-        task_lock(current);
-        current->signal->tty = tty;
-        task_unlock(current);
-        current->signal->tty_old_pgrp = 0;
-        tty->session = current->signal->session;
-        tty->pgrp = process_group(current);
-        return 0;
+        proc_set_tty(current, tty);
+unlock:
+        mutex_unlock(&tty_mutex);
+        return ret;
 }
 
 /**
@@ -2935,7 +2959,7 @@ static int tiocsctty(struct tty_struct *tty, int arg)
  *      Obtain the process group of the tty. If there is no process group
  *      return an error.
  *
- *      Locking: none. Reference to ->signal->tty is safe.
+ *      Locking: none. Reference to current->signal->tty is safe.
  */
 
 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -2959,8 +2983,6 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
  *      permitted where the tty session is our session.
  *
  *      Locking: None
- *
- *      FIXME: current->signal->tty referencing is unsafe.
  */
 
 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -2974,13 +2996,13 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
                 return retval;
         if (!current->signal->tty ||
             (current->signal->tty != real_tty) ||
-            (real_tty->session != current->signal->session))
+            (real_tty->session != process_session(current)))
                 return -ENOTTY;
         if (get_user(pgrp, p))
                 return -EFAULT;
         if (pgrp < 0)
                 return -EINVAL;
-        if (session_of_pgrp(pgrp) != current->signal->session)
+        if (session_of_pgrp(pgrp) != process_session(current))
                 return -EPERM;
         real_tty->pgrp = pgrp;
         return 0;
@@ -2995,7 +3017,7 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
  *      Obtain the session id of the tty. If there is no session
  *      return an error.
  *
- *      Locking: none. Reference to ->signal->tty is safe.
+ *      Locking: none. Reference to current->signal->tty is safe.
  */
 
 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -3039,19 +3061,20 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
  *      timed break functionality.
  *
  *      Locking:
- *              None
+ *              atomic_write_lock serializes
  *
- *      FIXME:
- *              What if two overlap
  */
 
 static int send_break(struct tty_struct *tty, unsigned int duration)
 {
+        if (mutex_lock_interruptible(&tty->atomic_write_lock))
+                return -EINTR;
         tty->driver->break_ctl(tty, -1);
         if (!signal_pending(current)) {
                 msleep_interruptible(duration);
         }
         tty->driver->break_ctl(tty, 0);
+        mutex_unlock(&tty->atomic_write_lock);
         if (signal_pending(current))
                 return -EINTR;
         return 0;
@@ -3144,6 +3167,8 @@ int tty_ioctl(struct inode * inode, struct file * file,
         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)
@@ -3211,14 +3236,11 @@ int tty_ioctl(struct inode * inode, struct file * file,
                         clear_bit(TTY_EXCLUSIVE, &tty->flags);
                         return 0;
                 case TIOCNOTTY:
-                        /* FIXME: taks lock or tty_mutex ? */
                         if (current->signal->tty != tty)
                                 return -ENOTTY;
                         if (current->signal->leader)
                                 disassociate_ctty(0);
-                        task_lock(current);
-                        current->signal->tty = NULL;
-                        task_unlock(current);
+                        proc_clear_tty(current);
                         return 0;
                 case TIOCSCTTY:
                         return tiocsctty(tty, arg);
@@ -3302,12 +3324,13 @@ int tty_ioctl(struct inode * inode, struct file * file,
  * Nasty bug: do_SAK is being called in interrupt context.  This can
  * deadlock.  We punt it up to process context.  AKPM - 16Mar2001
  */
-static void __do_SAK(void *arg)
+static void __do_SAK(struct work_struct *work)
 {
+        struct tty_struct *tty =
+                container_of(work, struct tty_struct, SAK_work);
 #ifdef TTY_SOFT_SAK
         tty_hangup(tty);
 #else
-        struct tty_struct *tty = arg;
         struct task_struct *g, *p;
         int session;
         int             i;
@@ -3317,7 +3340,7 @@ static void __do_SAK(void *arg)
         
         if (!tty)
                 return;
-        session  = tty->session;
+        session = tty->session;
         
         /* We don't want an ldisc switch during this */
         disc = tty_ldisc_ref(tty);
@@ -3332,7 +3355,7 @@ static void __do_SAK(void *arg)
         /* Kill the entire session */
         do_each_task_pid(session, PIDTYPE_SID, p) {
                 printk(KERN_NOTICE "SAK: killed process %d"
-                        " (%s): p->signal->session==tty->session\n",
+                        " (%s): process_session(p)==tty->session\n",
                         p->pid, p->comm);
                 send_sig(SIGKILL, p, 1);
         } while_each_task_pid(session, PIDTYPE_SID, p);
@@ -3342,7 +3365,7 @@ static void __do_SAK(void *arg)
         do_each_thread(g, p) {
                 if (p->signal->tty == tty) {
                         printk(KERN_NOTICE "SAK: killed process %d"
-                            " (%s): p->signal->session==tty->session\n",
+                            " (%s): process_session(p)==tty->session\n",
                             p->pid, p->comm);
                         send_sig(SIGKILL, p, 1);
                         continue;
@@ -3386,7 +3409,7 @@ void do_SAK(struct tty_struct *tty)
 {
         if (!tty)
                 return;
-        PREPARE_WORK(&tty->SAK_work, __do_SAK, tty);
+        PREPARE_WORK(&tty->SAK_work, __do_SAK);
         schedule_work(&tty->SAK_work);
 }
 
@@ -3394,7 +3417,7 @@ EXPORT_SYMBOL(do_SAK);
 
 /**
  *      flush_to_ldisc
- *      @private_: tty structure passed from work queue.
+ *      @work: tty structure passed from work queue.
  *
  *      This routine is called out of the software interrupt to flush data
  *      from the buffer chain to the line discipline.
@@ -3404,9 +3427,10 @@ EXPORT_SYMBOL(do_SAK);
  *      receive_buf method is single threaded for each tty instance.
  */
  
-static void flush_to_ldisc(void *private_)
+static void flush_to_ldisc(struct work_struct *work)
 {
-        struct tty_struct *tty = (struct tty_struct *) private_;
+        struct tty_struct *tty =
+                container_of(work, struct tty_struct, buf.work.work);
         unsigned long   flags;
         struct tty_ldisc *disc;
         struct tty_buffer *tbuf, *head;
@@ -3451,84 +3475,6 @@ static void flush_to_ldisc(void *private_)
         tty_ldisc_deref(disc);
 }
 
-/*
- * Routine which returns the baud rate of the tty
- *
- * Note that the baud_table needs to be kept in sync with the
- * include/asm/termbits.h file.
- */
-static int baud_table[] = {
-        0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
-        9600, 19200, 38400, 57600, 115200, 230400, 460800,
-#ifdef __sparc__
-        76800, 153600, 307200, 614400, 921600
-#else
-        500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
-        2500000, 3000000, 3500000, 4000000
-#endif
-};
-
-static int n_baud_table = ARRAY_SIZE(baud_table);
-
-/**
- *      tty_termios_baud_rate
- *      @termios: termios structure
- *
- *      Convert termios baud rate data into a speed. This should be called
- *      with the termios lock held if this termios is a terminal termios
- *      structure. May change the termios data.
- *
- *      Locking: none
- */
- 
-int tty_termios_baud_rate(struct termios *termios)
-{
-        unsigned int cbaud;
-        
-        cbaud = termios->c_cflag & CBAUD;
-
-        if (cbaud & CBAUDEX) {
-                cbaud &= ~CBAUDEX;
-
-                if (cbaud < 1 || cbaud + 15 > n_baud_table)
-                        termios->c_cflag &= ~CBAUDEX;
-                else
-                        cbaud += 15;
-        }
-        return baud_table[cbaud];
-}
-
-EXPORT_SYMBOL(tty_termios_baud_rate);
-
-/**
- *      tty_get_baud_rate       -       get tty bit rates
- *      @tty: tty to query
- *
- *      Returns the baud rate as an integer for this terminal. The
- *      termios lock must be held by the caller and the terminal bit
- *      flags may be updated.
- *
- *      Locking: none
- */
- 
-int tty_get_baud_rate(struct tty_struct *tty)
-{
-        int baud = tty_termios_baud_rate(tty->termios);
-
-        if (baud == 38400 && tty->alt_speed) {
-                if (!tty->warned) {
-                        printk(KERN_WARNING "Use of setserial/setrocket to "
-                                            "set SPD_* flags is deprecated\n");
-                        tty->warned = 1;
-                }
-                baud = tty->alt_speed;
-        }
-        
-        return baud;
-}
-
-EXPORT_SYMBOL(tty_get_baud_rate);
-
 /**
  *      tty_flip_buffer_push    -       terminal
  *      @tty: tty to push
@@ -3551,7 +3497,7 @@ void tty_flip_buffer_push(struct tty_struct *tty)
         spin_unlock_irqrestore(&tty->buf.lock, flags);
 
         if (tty->low_latency)
-                flush_to_ldisc((void *) tty);
+                flush_to_ldisc(&tty->buf.work.work);
         else
                 schedule_delayed_work(&tty->buf.work, 1);
 }
@@ -3578,17 +3524,17 @@ static void initialize_tty_struct(struct tty_struct *tty)
         tty->overrun_time = jiffies;
         tty->buf.head = tty->buf.tail = NULL;
         tty_buffer_init(tty);
-        INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
+        INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc);
         init_MUTEX(&tty->buf.pty_sem);
-        init_MUTEX(&tty->termios_sem);
+        mutex_init(&tty->termios_mutex);
         init_waitqueue_head(&tty->write_wait);
         init_waitqueue_head(&tty->read_wait);
-        INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
+        INIT_WORK(&tty->hangup_work, do_tty_hangup);
         mutex_init(&tty->atomic_read_lock);
         mutex_init(&tty->atomic_write_lock);
         spin_lock_init(&tty->read_lock);
         INIT_LIST_HEAD(&tty->tty_files);
-        INIT_WORK(&tty->SAK_work, NULL, NULL);
+        INIT_WORK(&tty->SAK_work, NULL);
 }
 
 /*
@@ -3610,7 +3556,8 @@ static struct class *tty_class;
  *              This field is optional, if there is no known struct device
  *              for this tty device it can be set to NULL safely.
  *
- *      Returns a pointer to the class device (or ERR_PTR(-EFOO) on error).
+ *      Returns a pointer to the struct device for this tty device
+ *      (or ERR_PTR(-EFOO) on error).
  *
  *      This call is required to be made to register an individual tty device
  *      if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set.  If
@@ -3620,8 +3567,8 @@ static struct class *tty_class;
  *      Locking: ??
  */
 
-struct class_device *tty_register_device(struct tty_driver *driver,
-                                         unsigned index, struct device *device)
+struct device *tty_register_device(struct tty_driver *driver, unsigned index,
+                                   struct device *device)
 {
         char name[64];
         dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
@@ -3637,7 +3584,7 @@ struct class_device *tty_register_device(struct tty_driver *driver,
         else
                 tty_line_name(driver, index, name);
 
-        return class_device_create(tty_class, NULL, dev, device, "%s", name);
+        return device_create(tty_class, device, dev, name);
 }
 
 /**
@@ -3653,7 +3600,7 @@ struct class_device *tty_register_device(struct tty_driver *driver,
 
 void tty_unregister_device(struct tty_driver *driver, unsigned index)
 {
-        class_device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index);
+        device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index);
 }
 
 EXPORT_SYMBOL(tty_register_device);
@@ -3678,7 +3625,8 @@ void put_tty_driver(struct tty_driver *driver)
         kfree(driver);
 }
 
-void tty_set_operations(struct tty_driver *driver, struct tty_operations *op)
+void tty_set_operations(struct tty_driver *driver,
+                        const struct tty_operations *op)
 {
         driver->open = op->open;
         driver->close = op->close;
@@ -3749,8 +3697,8 @@ int tty_register_driver(struct tty_driver *driver)
 
         if (p) {
                 driver->ttys = (struct tty_struct **)p;
-                driver->termios = (struct termios **)(p + driver->num);
-                driver->termios_locked = (struct termios **)(p + driver->num * 2);
+                driver->termios = (struct ktermios **)(p + driver->num);
+                driver->termios_locked = (struct ktermios **)(p + driver->num * 2);
         } else {
                 driver->ttys = NULL;
                 driver->termios = NULL;
@@ -3789,7 +3737,7 @@ EXPORT_SYMBOL(tty_register_driver);
 int tty_unregister_driver(struct tty_driver *driver)
 {
         int i;
-        struct termios *tp;
+        struct ktermios *tp;
         void *p;
 
         if (driver->refcount)
@@ -3827,9 +3775,52 @@ int tty_unregister_driver(struct tty_driver *driver)
         cdev_del(&driver->cdev);
         return 0;
 }
-
 EXPORT_SYMBOL(tty_unregister_driver);
 
+dev_t tty_devnum(struct tty_struct *tty)
+{
+        return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
+}
+EXPORT_SYMBOL(tty_devnum);
+
+void proc_clear_tty(struct task_struct *p)
+{
+        spin_lock_irq(&p->sighand->siglock);
+        p->signal->tty = NULL;
+        spin_unlock_irq(&p->sighand->siglock);
+}
+EXPORT_SYMBOL(proc_clear_tty);
+
+void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
+{
+        if (tty) {
+                tty->session = process_session(tsk);
+                tty->pgrp = process_group(tsk);
+        }
+        tsk->signal->tty = tty;
+        tsk->signal->tty_old_pgrp = 0;
+}
+
+void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
+{
+        spin_lock_irq(&tsk->sighand->siglock);
+        __proc_set_tty(tsk, tty);
+        spin_unlock_irq(&tsk->sighand->siglock);
+}
+
+struct tty_struct *get_current_tty(void)
+{
+        struct tty_struct *tty;
+        WARN_ON_ONCE(!mutex_is_locked(&tty_mutex));
+        tty = current->signal->tty;
+        /*
+         * session->tty can be changed/cleared from under us, make sure we
+         * issue the load. The obtained pointer, when not NULL, is valid as
+         * long as we hold tty_mutex.
+         */
+        barrier();
+        return tty;
+}
 
 /*
  * Initialize the console device. This is called *early*, so
@@ -3892,20 +3883,20 @@ 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");
-        class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
+        device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "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");
-        class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console");
+        device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "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");
-        class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
+        device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx");
 #endif
 
 #ifdef CONFIG_VT
@@ -3913,7 +3904,7 @@ 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");
-        class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
+        device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0");
 
         vty_init();
 #endif