tty: BKL pushdown
[pandora-kernel.git] / drivers / char / tty_io.c
index 613ec81..0b0354b 100644 (file)
@@ -152,8 +152,7 @@ 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);
@@ -1155,6 +1154,48 @@ 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->poll_init &&
+                               !p->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
@@ -1163,7 +1204,7 @@ 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: none - FIXME: review this
  */
 
 int tty_check_change(struct tty_struct *tty)
@@ -1205,8 +1246,8 @@ 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 +1263,7 @@ 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 +1276,7 @@ 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 +1289,7 @@ 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 +1301,7 @@ 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,
 };
@@ -1584,16 +1625,17 @@ 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 +1648,6 @@ void disassociate_ctty(int on_exit)
                        put_pid(old_pgrp);
                }
                mutex_unlock(&tty_mutex);
-               unlock_kernel();
                return;
        }
        if (tty_pgrp) {
@@ -1641,7 +1682,6 @@ void disassociate_ctty(int on_exit)
        read_lock(&tasklist_lock);
        session_clear_tty(task_session(current));
        read_unlock(&tasklist_lock);
-       unlock_kernel();
 }
 
 /**
@@ -1651,8 +1691,10 @@ 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);
 }
 
@@ -1672,19 +1714,24 @@ 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);
        }
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->driver->stop)
                (tty->driver->stop)(tty);
 }
@@ -1701,19 +1748,24 @@ 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);
        }
+       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->driver->start)
                (tty->driver->start)(tty);
        /* If we have a running line discipline it may need kicking */
@@ -1757,13 +1809,11 @@ 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);
        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 +1901,7 @@ 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;
@@ -2713,7 +2761,6 @@ got_driver:
                __proc_set_tty(current, tty);
        spin_unlock_irq(&current->sighand->siglock);
        mutex_unlock(&tty_mutex);
-       tty_audit_opening();
        return 0;
 }
 
@@ -2776,10 +2823,8 @@ static int ptmx_open(struct inode *inode, struct file *filp)
 
        check_tty_count(tty, "tty_open");
        retval = ptm_driver->open(tty, filp);
-       if (!retval) {
-               tty_audit_opening();
+       if (!retval)
                return 0;
-       }
 out1:
        release_dev(filp);
        return retval;
@@ -3031,10 +3076,13 @@ 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;
 }
 
@@ -3123,7 +3171,7 @@ 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
  */
 
 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -3198,10 +3246,16 @@ 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;
 }
 
 /**
@@ -3219,16 +3273,21 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
 
 static int send_break(struct tty_struct *tty, unsigned int duration)
 {
+       int retval = -EINTR;
+
+       lock_kernel();
        if (tty_write_lock(tty, 0) < 0)
-               return -EINTR;
+               goto out;
        tty->driver->break_ctl(tty, -1);
        if (!signal_pending(current))
                msleep_interruptible(duration);
        tty->driver->break_ctl(tty, 0);
        tty_write_unlock(tty);
-       if (signal_pending(current))
-               return -EINTR;
-       return 0;
+       if (!signal_pending(current))
+               retval = 0;
+out:
+       unlock_kernel();
+       return retval;
 }
 
 /**
@@ -3248,7 +3307,9 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
        int retval = -EINVAL;
 
        if (tty->driver->tiocmget) {
+               lock_kernel();
                retval = tty->driver->tiocmget(tty, file);
+               unlock_kernel();
 
                if (retval >= 0)
                        retval = put_user(retval, p);
@@ -3298,7 +3359,9 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int
                set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
                clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
 
+               lock_kernel();
                retval = tty->driver->tiocmset(tty, file, set, clear);
+               unlock_kernel();
        }
        return retval;
 }
@@ -3306,20 +3369,18 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int
 /*
  * 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)
@@ -3328,13 +3389,19 @@ int tty_ioctl(struct inode *inode, struct file *file,
        /*
         * Break handling by driver
         */
+
+       retval = -EINVAL;
+
        if (!tty->driver->break_ctl) {
                switch (cmd) {
                case TIOCSBRK:
                case TIOCCBRK:
-                       if (tty->driver->ioctl)
-                               return tty->driver->ioctl(tty, file, cmd, arg);
-                       return -EINVAL;
+                       if (tty->driver->ioctl) {
+                               lock_kernel();
+                               retval = tty->driver->ioctl(tty, file, cmd, arg);
+                               unlock_kernel();
+                       }
+                       return retval;
 
                /* These two ioctl's always return success; even if */
                /* the driver doesn't support them. */
@@ -3342,7 +3409,9 @@ int tty_ioctl(struct inode *inode, struct file *file,
                case TCSBRKP:
                        if (!tty->driver->ioctl)
                                return 0;
+                       lock_kernel();
                        retval = tty->driver->ioctl(tty, file, cmd, arg);
+                       unlock_kernel();
                        if (retval == -ENOIOCTLCMD)
                                retval = 0;
                        return retval;
@@ -3362,7 +3431,9 @@ int tty_ioctl(struct inode *inode, struct file *file,
                if (retval)
                        return retval;
                if (cmd != TIOCCBRK) {
+                       lock_kernel();
                        tty_wait_until_sent(tty, 0);
+                       unlock_kernel();
                        if (signal_pending(current))
                                return -EINTR;
                }
@@ -3412,11 +3483,15 @@ int tty_ioctl(struct inode *inode, struct file *file,
         * Break handling
         */
        case TIOCSBRK:  /* Turn break on, unconditionally */
+               lock_kernel();
                tty->driver->break_ctl(tty, -1);
+               unlock_kernel();
                return 0;
 
        case TIOCCBRK:  /* Turn break off, unconditionally */
+               lock_kernel();
                tty->driver->break_ctl(tty, 0);
+               unlock_kernel();
                return 0;
        case TCSBRK:   /* SVID version: non-zero arg --> no break */
                /* non-zero arg means wait for all output data
@@ -3446,14 +3521,18 @@ int tty_ioctl(struct inode *inode, struct file *file,
                break;
        }
        if (tty->driver->ioctl) {
+               lock_kernel();
                retval = (tty->driver->ioctl)(tty, file, cmd, arg);
+               unlock_kernel();
                if (retval != -ENOIOCTLCMD)
                        return retval;
        }
        ld = tty_ldisc_ref_wait(tty);
        retval = -EINVAL;
        if (ld->ioctl) {
+               lock_kernel();
                retval = ld->ioctl(tty, file, cmd, arg);
+               unlock_kernel();
                if (retval == -ENOIOCTLCMD)
                        retval = -EINVAL;
        }
@@ -3731,6 +3810,7 @@ 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);
 }
@@ -3850,6 +3930,11 @@ void tty_set_operations(struct tty_driver *driver,
        driver->write_proc = op->write_proc;
        driver->tiocmget = op->tiocmget;
        driver->tiocmset = op->tiocmset;
+#ifdef CONFIG_CONSOLE_POLL
+       driver->poll_init = op->poll_init;
+       driver->poll_get_char = op->poll_get_char;
+       driver->poll_put_char = op->poll_put_char;
+#endif
 }