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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2008-04-30 00:53:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:40 -0700
commit04f378b198da233ca0aca341b113dc6579d46123 (patch)
tree696e7bd401125cee71ecaa2047c4273f38732554 /drivers/char/pty.c
parente52384426064bca0669a954736206adca7595d48 (diff)
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/pty.c')
-rw-r--r--drivers/char/pty.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 706ff34728f1..6288356b769d 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -181,6 +181,7 @@ static int pty_set_lock(struct tty_struct *tty, int __user * arg)
static void pty_flush_buffer(struct tty_struct *tty)
{
struct tty_struct *to = tty->link;
+ unsigned long flags;
if (!to)
return;
@@ -189,8 +190,10 @@ static void pty_flush_buffer(struct tty_struct *tty)
to->ldisc.flush_buffer(to);
if (to->packet) {
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
wake_up_interruptible(&to->read_wait);
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
}
}