diff options
| author | Alan Cox <alan@lxorguk.ukuu.org.uk> | 2008-04-30 11:53:29 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 19:29:40 +0400 |
| commit | 04f378b198da233ca0aca341b113dc6579d46123 (patch) | |
| tree | 696e7bd401125cee71ecaa2047c4273f38732554 /drivers/char/tty_ioctl.c | |
| parent | e52384426064bca0669a954736206adca7595d48 (diff) | |
| download | linux-04f378b198da233ca0aca341b113dc6579d46123.tar.xz | |
tty: BKL pushdown
- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
on the paths that historically held the lock
BKL now primarily protects open/close/ldisc change in the tty layer
[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/tty_ioctl.c')
| -rw-r--r-- | drivers/char/tty_ioctl.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c index f95a80b2265f..d6353d89b451 100644 --- a/drivers/char/tty_ioctl.c +++ b/drivers/char/tty_ioctl.c @@ -395,6 +395,7 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios) int canon_change; struct ktermios old_termios = *tty->termios; struct tty_ldisc *ld; + unsigned long flags; /* * Perform the actual termios internal changes under lock. @@ -429,11 +430,13 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios) STOP_CHAR(tty) == '\023' && START_CHAR(tty) == '\021'); if (old_flow != new_flow) { + spin_lock_irqsave(&tty->ctrl_lock, flags); tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); if (new_flow) tty->ctrl_status |= TIOCPKT_DOSTOP; else tty->ctrl_status |= TIOCPKT_NOSTOP; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); wake_up_interruptible(&tty->link->read_wait); } } @@ -905,6 +908,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { struct tty_struct *real_tty; + unsigned long flags; int retval; if (tty->driver->type == TTY_DRIVER_TYPE_PTY && @@ -963,6 +967,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, return -ENOTTY; if (get_user(pktmode, (int __user *) arg)) return -EFAULT; + spin_lock_irqsave(&tty->ctrl_lock, flags); if (pktmode) { if (!tty->packet) { tty->packet = 1; @@ -970,6 +975,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, } } else tty->packet = 0; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); return 0; } default: |