linux-stable.git/include/linux/tty.h, branch v3.19.3

tty: Convert tty->closing to int

2014-11-06T22:57:27+00:00

tty->closing is a bitfield member; prevent corruption from non-atomic
update by assigning a unique memory location.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove defunct serial_console_init() declaration

2014-11-06T04:18:30+00:00

serial_console_init() is not defined by the tty core; remove
declaration.

Note that the powerpc arch boot code contains a serial_console_init()
declaration in arch/powerpc/boot/ops.h which is restricted to
the powerpc arch boot.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove defunct pcxe_open() declaration

2014-11-06T04:18:30+00:00

pcxe_open() has no definition in mainline; remove declaration.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Flush ldisc buffer atomically with tty flip buffers

2014-11-06T02:50:43+00:00

tty_ldisc_flush() first clears the line discipline input buffer,
then clears the tty flip buffers. However, this allows for existing
data in the tty flip buffers to be added after the ldisc input
buffer has been cleared, but before the flip buffers have been cleared.

Add an optional ldisc parameter to tty_buffer_flush() to allow
tty_ldisc_flush() to pass the ldisc to clear.

NB: Initially, the plan was to do this automatically in
tty_buffer_flush(). However, an audit of the behavior of existing
line disciplines showed that performing a ldisc buffer flush on
ioctl(TCFLSH) was not always the outcome. For example, some line
disciplines have flush_buffer() methods but not ioctl() methods,
so a ->flush_buffer() command would be unexpected.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove tty_unhangup() declaration

2014-11-06T02:50:42+00:00

The tty_unhangup() function is not defined.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Preset lock subclass for nested tty locks

2014-11-06T02:50:42+00:00

Eliminate the requirement of specifying the tty lock nesting at
lock time; instead, set the lock subclass for slave ptys at pty
install (normal ttys and master ptys use subclass 0).

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Change tty lock order to master->slave

2014-11-06T02:50:42+00:00

When releasing the master pty, the slave pty also needs to be locked
to prevent concurrent tty count changes for the slave pty and to
ensure that only one parallel master and slave release observe the
final close, and proceed to destruct the pty pair. Conversely, when
releasing the slave pty, locking the master pty is not necessary
(since the master's state can be inferred by the slave tty count).

Introduce tty_lock_slave()/tty_unlock_slave() which acquires/releases
the tty lock of the slave pty. Remove tty_lock_pair()/tty_unlock_pair().

Dropping the tty_lock is no longer required to re-establish a stable
lock order.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Simplify tty_ldisc_release() interface

2014-11-06T02:42:46+00:00

Passing the 'other' tty to tty_ldisc_release() only makes sense
for a pty pair; make o_tty function local instead.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove TTY_CLOSING

2014-11-06T02:24:10+00:00

Now that re-open is not permitted for a legacy BSD pty master,
using TTY_CLOSING to indicate when a tty can be torn-down is
no longer necessary.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove TTY_HUPPING

2014-11-06T02:24:10+00:00

Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.

Remove TTY_HUPPING bit definition.

Reviewed-by: Alan Cox 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman