diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 23:33:26 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-06 03:34:36 +0300 |
| commit | 54e8e5fcaae109f0303f52efb24f29bfac79ca86 (patch) | |
| tree | d0d4e39526384367fa195b61a5aa2de686170a7d | |
| parent | 6054c16e80318d32ee084a0f5620a863ae8cea33 (diff) | |
| download | linux-54e8e5fcaae109f0303f52efb24f29bfac79ca86.tar.xz | |
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>
| -rw-r--r-- | drivers/tty/n_tty.c | 4 | ||||
| -rw-r--r-- | drivers/tty/pty.c | 8 |
2 files changed, 6 insertions, 6 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index d521058ee55a..cd725cc6e21e 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -351,13 +351,13 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty) { unsigned long flags; - spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link->packet) { + spin_lock_irqsave(&tty->ctrl_lock, flags); tty->ctrl_status |= TIOCPKT_FLUSHREAD; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (waitqueue_active(&tty->link->read_wait)) wake_up_interruptible(&tty->link->read_wait); } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); } /** 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); } /** |