user/sven/linux.git/include/linux/tty.h, branch v4.0

tty: Remove external interface for tty_set_termios()

2015-02-02T18:11:28Z

tty_set_termios() is an internal helper intended for file scope use. UART drivers which are capable of driving the RTS pin must properly handle the tiocmset() method, regardless of termios settings. A failure to do so is a UART driver bug and should be fixed there. Do not use this interface to workaround UART driver bugs. Cc: Johan Hedberg Cc: Signed-off-by: Peter Hurley Acked-by: Marcel Holtmann Signed-off-by: Greg Kroah-Hartman

n_tty: Fix signal handling flushes

2015-02-02T18:11:27Z

BRKINT and ISIG requires input and output flush when a signal char is received. However, the order of operations is significant since parallel i/o may be ongoing. Merge the signal handling for BRKINT with ISIG handling. Process the signal first. This ensures any ongoing i/o is aborted; without this, a waiting writer may continue writing after the flush occurs and after the signal char has been echoed. Write lock the termios_rwsem, which excludes parallel writers from pushing new i/o until after the output buffers are flushed; claiming the write lock is necessary anyway to exclude parallel readers while the read buffer is flushed. Subclass the termios_rwsem for ptys since the slave pty performing the flush may appear to reorder the termios_rwsem->tty buffer lock lock order; adding annotation clarifies that slave tty_buffer lock-> slave termios_rwsem -> master tty_buffer lock is a valid lock order. Flush the echo buffer. In this context, the echo buffer is 'output'. Otherwise, the output will appear discontinuous because the output buffer was cleared which contains older output than the echo buffer. Open-code the read buffer flush since the input worker does not need kicking (this is the input worker). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

pty: Fix buffer flush deadlock

2015-02-02T18:11:27Z

The pty driver does not clear its write buffer when commanded. This is to avoid an apparent deadlock between parallel flushes from both pty ends; specifically when handling either BRK or INTR input. However, parallel flushes from this source is not possible since the pty master can never be set to BRKINT or ISIG. Parallel flushes from other sources are possible but these do not threaten deadlocks. Annotate the tty buffer mutex for lockdep to represent the nested tty_buffer locking which occurs when the pty slave is processing input (its buffer mutex held) and receives INTR or BRK and acquires the linked tty buffer mutex via tty_buffer_flush(). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Make lock subclasses available for other tty locks

2015-02-02T18:11:27Z

Besides nested legacy_mutex locking which is required on pty pair teardown, other nested pty operations require lock subclassing. Move lock subclass definition to tty interface header, include/linux/tty.h, and document its use. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Convert tty->closing to int

2014-11-06T22:57:27Z

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

2014-11-06T04:18:30Z

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

2014-11-06T04:18:30Z

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

2014-11-06T02:50:43Z

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

2014-11-06T02:50:42Z

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

2014-11-06T02:50:42Z

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