[PATCH] tty: make __proc_set_tty static
[linux-drm-fsl-dcu.git] / drivers / char / tty_io.c
index b3cfc8bc613c7bbfeee7ef7ce037e638793f32a0..b9fce77c8f032ce0f7af9803eee6d9f6ba20e79d 100644 (file)
 #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);
@@ -126,7 +128,7 @@ 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);
@@ -152,7 +154,8 @@ static int tty_release(struct inode *, struct file *);
 int tty_ioctl(struct inode * inode, struct file * file,
              unsigned int cmd, unsigned long arg);
 static int tty_fasync(int fd, struct file * filp, int on);
-static void release_mem(struct tty_struct *tty, int idx);
+static void release_tty(struct tty_struct *tty, int idx);
+static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
 
 /**
  *     alloc_tty_struct        -       allocate a tty object
@@ -250,7 +253,7 @@ 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;
 }
@@ -259,18 +262,6 @@ 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
@@ -614,7 +605,7 @@ 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)
@@ -915,7 +906,7 @@ 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)
@@ -1251,6 +1242,22 @@ 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
@@ -1267,12 +1274,12 @@ 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(struct work_struct *work)
 {
@@ -1339,11 +1346,7 @@ static void do_tty_hangup(struct work_struct *work)
         * N_TTY.
         */
        if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
-       {
-               mutex_lock(&tty->termios_mutex);
-               *tty->termios = tty->driver->init_termios;
-               mutex_unlock(&tty->termios_mutex);
-       }
+               tty_reset_termios(tty);
        
        /* Defer ldisc switch */
        /* tty_deferred_ldisc_switch(N_TTY);
@@ -1354,14 +1357,18 @@ static void do_tty_hangup(struct work_struct *work)
        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);
@@ -1453,6 +1460,14 @@ 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
@@ -1469,31 +1484,35 @@ 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();        
@@ -1505,19 +1524,29 @@ 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();
 }
 
@@ -1584,7 +1613,6 @@ void start_tty(struct tty_struct *tty)
 
        /* If we have a running line discipline it may need kicking */
        tty_wakeup(tty);
-       wake_up_interruptible(&tty->write_wait);
 }
 
 EXPORT_SYMBOL(start_tty);
@@ -1615,7 +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)))
@@ -1718,7 +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;
        }
@@ -1749,7 +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;
        
@@ -1856,8 +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 */
@@ -1904,7 +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;
@@ -1912,11 +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) {
@@ -1937,19 +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));
                }
 
                /*
@@ -1975,7 +2003,7 @@ static int init_dev(struct tty_driver *driver, int idx,
 
        /* 
         * All structures have been allocated, so now we install them.
-        * Failures after this point use release_mem to clean up, so 
+        * Failures after this point use release_tty to clean up, so
         * there's no need to null out the local pointers.
         */
        if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
@@ -1988,13 +2016,16 @@ 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++;
 
        /* 
         * Structures all installed ... call the ldisc open routines.
-        * If we fail here just call release_mem to clean up.  No need
-        * to decrement the use counts, as release_mem doesn't care.
+        * If we fail here just call release_tty to clean up.  No need
+        * to decrement the use counts, as release_tty doesn't care.
         */
 
        if (tty->ldisc.open) {
@@ -2064,17 +2095,17 @@ fail_no_mem:
        retval = -ENOMEM;
        goto end_init;
 
-       /* call the tty release_mem routine to clean out this slot */
+       /* call the tty release_tty routine to clean out this slot */
 release_mem_out:
        if (printk_ratelimit())
                printk(KERN_INFO "init_dev: ldisc open failed, "
                                 "clearing slot %d\n", idx);
-       release_mem(tty, idx);
+       release_tty(tty, idx);
        goto end_init;
 }
 
 /**
- *     release_mem             -       release tty structure memory
+ *     release_one_tty         -       release tty structure memory
  *
  *     Releases memory associated with a tty structure, and clears out the
  *     driver table slots. This function is called when a device is no longer
@@ -2086,37 +2117,14 @@ release_mem_out:
  *     of ttys that the driver keeps.
  *             FIXME: should we require tty_mutex is held here ??
  */
-
-static void release_mem(struct tty_struct *tty, int idx)
+static void release_one_tty(struct tty_struct *tty, int idx)
 {
-       struct tty_struct *o_tty;
-       struct termios *tp;
        int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM;
-
-       if ((o_tty = tty->link) != NULL) {
-               if (!devpts)
-                       o_tty->driver->ttys[idx] = NULL;
-               if (o_tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
-                       tp = o_tty->termios;
-                       if (!devpts)
-                               o_tty->driver->termios[idx] = NULL;
-                       kfree(tp);
-
-                       tp = o_tty->termios_locked;
-                       if (!devpts)
-                               o_tty->driver->termios_locked[idx] = NULL;
-                       kfree(tp);
-               }
-               o_tty->magic = 0;
-               o_tty->driver->refcount--;
-               file_list_lock();
-               list_del_init(&o_tty->tty_files);
-               file_list_unlock();
-               free_tty_struct(o_tty);
-       }
+       struct ktermios *tp;
 
        if (!devpts)
                tty->driver->ttys[idx] = NULL;
+
        if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
                tp = tty->termios;
                if (!devpts)
@@ -2129,15 +2137,39 @@ static void release_mem(struct tty_struct *tty, int idx)
                kfree(tp);
        }
 
+
        tty->magic = 0;
        tty->driver->refcount--;
+
        file_list_lock();
        list_del_init(&tty->tty_files);
        file_list_unlock();
-       module_put(tty->driver->owner);
+
        free_tty_struct(tty);
 }
 
+/**
+ *     release_tty             -       release tty structure memory
+ *
+ *     Release both @tty and a possible linked partner (think pty pair),
+ *     and decrement the refcount of the backing module.
+ *
+ *     Locking:
+ *             tty_mutex - sometimes only
+ *             takes the file list lock internally when working on the list
+ *     of ttys that the driver keeps.
+ *             FIXME: should we require tty_mutex is held here ??
+ */
+static void release_tty(struct tty_struct *tty, int idx)
+{
+       struct tty_driver *driver = tty->driver;
+
+       if (tty->link)
+               release_one_tty(tty->link, idx);
+       release_one_tty(tty, idx);
+       module_put(driver->owner);
+}
+
 /*
  * Even releasing the tty structures is a tricky business.. We have
  * to be very careful that the structures are all released at the
@@ -2156,7 +2188,7 @@ 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");
@@ -2337,16 +2369,10 @@ 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);
        }
 
@@ -2411,10 +2437,10 @@ static void release_dev(struct file * filp)
                tty_set_termios_ldisc(o_tty,N_TTY); 
        }
        /*
-        * The release_mem function takes care of the details of clearing
+        * The release_tty function takes care of the details of clearing
         * the slots and preserving the termios structure.
         */
-       release_mem(tty, idx);
+       release_tty(tty, idx);
 
 #ifdef CONFIG_UNIX98_PTYS
        /* Make this pty number available for reallocation */
@@ -2443,9 +2469,9 @@ 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)
@@ -2467,12 +2493,13 @@ 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;
@@ -2547,17 +2574,16 @@ 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;
 }
 
@@ -2672,7 +2698,7 @@ 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);
@@ -2688,7 +2714,7 @@ 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);
@@ -2747,7 +2773,7 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
  *
  *     Copies the kernel idea of the window size into the user buffer.
  *
- *     Locking: tty->termios_sem is taken to ensure the winsize data
+ *     Locking: tty->termios_mutex is taken to ensure the winsize data
  *             is consistent.
  */
 
@@ -2774,8 +2800,8 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
  *     Locking:
  *             Called function use the console_sem is used to ensure we do
  *     not try and resize the console twice at once.
- *             The tty->termios_sem is used to ensure we don't double
- *     resize and get confused. Lock order - tty->termios.sem before
+ *             The tty->termios_mutex is used to ensure we don't double
+ *     resize and get confused. Lock order - tty->termios_mutex before
  *     console sem
  */
 
@@ -2880,25 +2906,28 @@ 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
  *             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
@@ -2908,24 +2937,18 @@ 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;
+               }
        }
-       mutex_lock(&tty_mutex);
-       task_lock(current);
-       current->signal->tty = tty;
-       task_unlock(current);
+       proc_set_tty(current, tty);
+unlock:
        mutex_unlock(&tty_mutex);
-       current->signal->tty_old_pgrp = 0;
-       tty->session = current->signal->session;
-       tty->pgrp = process_group(current);
-       return 0;
+       return ret;
 }
 
 /**
@@ -2937,7 +2960,7 @@ 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)
@@ -2974,13 +2997,13 @@ 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 +3018,7 @@ 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)
@@ -3214,14 +3237,11 @@ 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);
@@ -3305,10 +3325,8 @@ 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(struct work_struct *work)
+void __do_SAK(struct tty_struct *tty)
 {
-       struct tty_struct *tty =
-               container_of(work, struct tty_struct, SAK_work);
 #ifdef TTY_SOFT_SAK
        tty_hangup(tty);
 #else
@@ -3316,18 +3334,13 @@ static void __do_SAK(struct work_struct *work)
        int session;
        int             i;
        struct file     *filp;
-       struct tty_ldisc *disc;
        struct fdtable *fdt;
        
        if (!tty)
                return;
-       session  = tty->session;
+       session = tty->session;
        
-       /* We don't want an ldisc switch during this */
-       disc = tty_ldisc_ref(tty);
-       if (disc && disc->flush_buffer)
-               disc->flush_buffer(tty);
-       tty_ldisc_deref(disc);
+       tty_ldisc_flush(tty);
 
        if (tty->driver->flush_buffer)
                tty->driver->flush_buffer(tty);
@@ -3336,7 +3349,7 @@ static void __do_SAK(struct work_struct *work)
        /* 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);
@@ -3346,7 +3359,7 @@ static void __do_SAK(struct work_struct *work)
        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;
@@ -3380,6 +3393,13 @@ static void __do_SAK(struct work_struct *work)
 #endif
 }
 
+static void do_SAK_work(struct work_struct *work)
+{
+       struct tty_struct *tty =
+               container_of(work, struct tty_struct, SAK_work);
+       __do_SAK(tty);
+}
+
 /*
  * The tq handling here is a little racy - tty->SAK_work may already be queued.
  * Fortunately we don't need to worry, because if ->SAK_work is already queued,
@@ -3390,7 +3410,7 @@ void do_SAK(struct tty_struct *tty)
 {
        if (!tty)
                return;
-       PREPARE_WORK(&tty->SAK_work, __do_SAK);
+       PREPARE_WORK(&tty->SAK_work, do_SAK_work);
        schedule_work(&tty->SAK_work);
 }
 
@@ -3456,84 +3476,6 @@ static void flush_to_ldisc(struct work_struct *work)
        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
@@ -3756,8 +3698,8 @@ 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;
@@ -3796,7 +3738,7 @@ 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)
@@ -3834,9 +3776,53 @@ 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);
+
+static 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;
+}
+EXPORT_SYMBOL_GPL(get_current_tty);
 
 /*
  * Initialize the console device. This is called *early*, so