diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 21:33:26 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-06 01:34:36 +0100 |
| commit | 54e8e5fcaae109f0303f52efb24f29bfac79ca86 (patch) | |
| tree | d0d4e39526384367fa195b61a5aa2de686170a7d /drivers/tty/pty.c | |
| parent | tty: Use spin_lock_irq() for ctrl_lock when interrupts enabled (diff) | |
| download | linux-54e8e5fcaae109f0303f52efb24f29bfac79ca86.tar.xz linux-54e8e5fcaae109f0303f52efb24f29bfac79ca86.zip | |
pty: Don't claim slave's ctrl_lock for master's packet mode
The slave's ctrl_lock serializes updates to the ctrl_status field
only, whereas the master's ctrl_lock serializes updates to the
packet mode enable (ie., the master does not have ctrl_status and
the slave does not have packet mode). Thus, claiming the slave's
ctrl_lock to access ->packet is useless.
Unlocked reads of ->packet are already smp-safe.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/pty.c')
| -rw-r--r-- | drivers/tty/pty.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 29b5eeb01856..e554393d5551 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -339,26 +339,26 @@ static void pty_start(struct tty_struct *tty) { unsigned long flags; - spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link && tty->link->packet) { + spin_lock_irqsave(&tty->ctrl_lock, flags); tty->ctrl_status &= ~TIOCPKT_STOP; tty->ctrl_status |= TIOCPKT_START; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); } static void pty_stop(struct tty_struct *tty) { unsigned long flags; - spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link && tty->link->packet) { + spin_lock_irqsave(&tty->ctrl_lock, flags); tty->ctrl_status &= ~TIOCPKT_START; tty->ctrl_status |= TIOCPKT_STOP; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); } /** |