BMC/Intel-BMC/linux.git/drivers/tty/tty_port.c, branch dev-4.6

tty: Remove ASYNC_CLOSING

2016-01-28T22:19:12+00:00

The tty core no longer provides nor uses ASYNC_CLOSING; remove from tty_port_close_start() and tty_port_close_end() as well as tty drivers which open-code these state changes. Unfortunately, even though the bit is masked from userspace, its inclusion in a uapi header precludes removing the macro. Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: linux-s390@vger.kernel.org Cc: Mikael Starvik Cc: Jesper Nilsson Cc: linux-cris-kernel@axis.com Cc: Samuel Ortiz Cc: "David S. Miller" Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Use termios c_*flag macros

2016-01-28T22:13:44+00:00

Expressions of the form "tty->termios.c_*flag & FLAG" are more clearly expressed with the termios flags macros, I_FLAG(), C_FLAG(), O_FLAG(), and L_FLAG(). Convert treewide. Signed-off-by: Peter Hurley Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

tty: Allow unreadable mess to be > 80 chars

2016-01-28T22:13:44+00:00

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

tty: Define tty_*() printk macros

2015-12-14T03:59:48+00:00

Since not all ttys are devices (eg., SysV ptys), dev_*() printk macros cannot be used. Define tty_*() printk macros that output in similar format to dev_*() macros (ie., : .....). Transform the most-trivial printk( LEVEL ...) usage to tty_*() usage. NB: The function name has been eliminated from messages with unique context, or prefixed to the format when given. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Abstract tty buffer work

2015-10-18T04:32:21+00:00

Introduce API functions to restart and cancel tty buffer work, rather than manipulate buffer work directly. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Remove tty_port::close_wait

2015-10-18T04:11:29+00:00

With the removal of tty_wait_until_sent_from_close(), tty drivers no longer wait during open for parallel closes to complete (instead, the tty core waits before calling the driver open() method). Thus, the close_wait waitqueue is no longer used for waiting. Remove struct tty_port::close_wait. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Remove ASYNC_CLOSING checks in open()/hangup() methods

2015-10-18T04:11:29+00:00

Since at least before 2.6.30, tty drivers that do not drop the tty lock while closing cannot observe ASYNC_CLOSING set while holding the tty lock; this includes the tty driver's open() and hangup() methods, since the tty core calls these methods holding the tty lock. For these drivers, waiting for ASYNC_CLOSING to clear while opening is not required, since this condition cannot occur. Similarly, even when the open() method drops and reacquires the tty lock after blocking, ASYNC_CLOSING cannot be set (again, for drivers that do not drop the tty lock while closing). Now that tty port drivers no longer drop the tty lock while closing (since 'tty: Remove tty_wait_until_sent_from_close()'), the same conditions apply: waiting for ASYNC_CLOSING to clear while opening is not required, nor is re-checking ASYNC_CLOSING after dropping and reacquiring the tty lock while blocking (eg., in *_block_til_ready()). Note: The ASYNC_CLOSING flag state is still maintained since several bitrotting drivers use it for (dubious) other purposes. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Remove tty_wait_until_sent_from_close()

2015-10-18T04:11:29+00:00

tty_wait_until_sent_from_close() drops the tty lock while waiting for the tty driver to finish sending previously accepted data (ie., data remaining in its write buffer and transmit fifo). tty_wait_until_sent_from_close() was added by commit a57a7bf3fc7e ("TTY: define tty_wait_until_sent_from_close") to prevent the entire tty subsystem from being unable to open new ttys while waiting for one tty to close while output drained. However, since commit 0911261d4cb6 ("tty: Don't take tty_mutex for tty count changes"), holding a tty lock while closing does not prevent other ttys from being opened/closed/hung up, but only prevents lifetime event changes for the tty under lock. Holding the tty lock while waiting for output to drain does prevent parallel non-blocking opens (O_NONBLOCK) from advancing or returning while the tty lock is held. However, all parallel opens _already_ block even if the tty lock is dropped while closing and the parallel open advances. Blocking in open has been in mainline since at least 2.6.29 (see tty_port_block_til_ready(); note the test for O_NONBLOCK is _after_ the wait while ASYNC_CLOSING). IOW, before this patch a non-blocking open will sleep anyway for the _entire_ duration of a parallel hardware shutdown, and when it wakes, the error return will cause a release of its tty, and it will restart with a fresh attempt to open. Similarly with a blocking open that is already waiting; when it's woken, the hardware shutdown has already completed to ASYNC_INITIALIZED is not set, which forces a release and restart as well. So, holding the tty lock across the _entire_ close (which is what this patch does), even while waiting for output to drain, is equivalent to the current outcome wrt parallel opens. Cc: Alan Cox Cc: David Laight CC: Arnd Bergmann CC: Karsten Keil CC: linuxppc-dev@lists.ozlabs.org Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Deletion of unnecessary checks before two function calls

2014-11-27T03:35:49+00:00

The functions put_device() and tty_kref_put() test whether their argument is NULL and then return immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring Signed-off-by: Greg Kroah-Hartman

tty: Flush tty buffers after hardware shutdown

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

The line discipline buffer and the tty buffers must be flushed again after hardware shutdown; otherwise, a brief window exists between the ldisc flush in tty_port_close_start() and the subsequent tty_port_shutdown(), during which more data could be received into the tty buffers. A racing open might then be able to receive data from the previous session. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman