linux-stable.git/drivers/tty/n_tty.c, branch linux-3.9.y

TTY: Fix tty miss restart after we turn off flow-control

2013-06-07T19:52:25+00:00

commit dab73b4eb9ef924a2b90dab84e539076d82b256f upstream.

I meet emacs hang in start if I do the operation below:
  1: echo 3 > /proc/sys/vm/drop_caches
  2: emacs BigFile
  3: Press CTRL-S follow 2 immediately

Then emacs hang on, CTRL-Q can't resume, the terminal
hang on, you can do nothing with this terminal except
close it.

The reason is before emacs takeover control the tty,
we use CTRL-S to XOFF it. Then when emacs takeover the
control, it may don't use the flow-control, so emacs hang.
This patch fix it.

This patch will fix a kind of strange tty relation hang problem,
I believe I meet it with vim in ssh, and also see below bug report:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=465823

Signed-off-by: Wang YanQing 
Signed-off-by: Greg Kroah-Hartman

pps: Move timestamp read into PPS code proper

2013-02-13T18:13:58+00:00

The PPS (Pulse-Per-Second) line discipline has developed a number of
unhealthy attachments to core tty data and functions, ultimately leading
to its breakage.

The previous patches fixed the crashing.  This one reduces coupling further
by eliminating the timestamp parameter from the dcd_change ldisc method.
This reduces header file linkage and makes the extension more generic,
and the timestamp read is delayed only slightly, from just before the
ldisc->ops->dcd_change method call to just after.

Fix attendant build breakage in
    drivers/tty/n_tty.c
    drivers/tty/tty_buffer.c
    drivers/staging/speakup/selection.c
    drivers/staging/dgrp/dgrp_*.c

Cc: William Hubbs 
Cc: Chris Brannon 
Cc: Kirk Reiser 
Cc: Samuel Thibault 
Signed-off-by: Peter Hurley 
Signed-off-by: George Spelvin 
Acked-by: Rodolfo Giometti 
Signed-off-by: Greg Kroah-Hartman

tty: Use raw spin lock to protect the TTY read section

2013-02-04T23:05:04+00:00

The "normal" spin lock that guards the N_TTY line discipline read section
is replaced by a raw spin lock.

On a PREEMP_RT system this prevents unwanted scheduling overhead when data is
read at the same time as data is being received: while RX IRQ threaded handling
is busy a TTY read call is performed from a RT priority > threaded IRQ priority.
The read call tries to take the read section spin lock (held by the threaded
IRQ) which blocks and causes a context switch to/from the threaded IRQ handler
until the spin lock is unlocked.

Signed-off-by: Ivo Sieben 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Revert "n_tty: Unthrottle tty when flushing read buffer"

2013-01-30T04:35:35+00:00

This reverts commit 58f82be334ede87aa6ff6fa1afdb05552be907be.

This was fixed by a previous patch already.

Signed-off-by: Greg Kroah-Hartman

n_tty: Unthrottle tty when flushing read buffer

2013-01-25T16:52:23+00:00

When the tty input buffer is full and thereby throttled,
flushing/resetting the read buffer should unthrottle to allow more
data to be received.

Signed-off-by: Karthik Manamcheri 
Signed-off-by: Greg Kroah-Hartman

tty: add missing newlines to WARN_RATELIMIT

2012-10-25T18:30:27+00:00

WARN_RATELIMIT() expects the warning to end with a newline if one
is needed.

Not doing so results in odd looking warnings such as:

[ 1339.454272] tty is NULLPid: 7147, comm: kworker/4:0 Tainted: G        W    3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #75

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

TTY: move tty buffers to tty_port

2012-10-22T23:58:28+00:00

So this is it. The big step why we did all the work over the past
kernel releases. Now everything is prepared, so nothing protects us
from doing that big step.

           |  |            \  \ nnnn/^l      |  |
           |  |             \  /     /       |  |
           |  '-,.__   =>    \/   ,-`    =>  |  '-,.__
           | O __.´´)        (  .`           | O __.´´)
            ~~~   ~~          ``              ~~~   ~~
The buffers are now in the tty_port structure and we can start
teaching the buffer helpers (insert char/string, flip etc.) to use
tty_port instead of tty_struct all around.

Signed-off-by: Jiri Slaby 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: n_tty, propagate n_tty_data

2012-10-22T23:53:01+00:00

In some funtions we need only n_tty_data, so pass it down directly in
case tty is not needed there.

Signed-off-by: Jiri Slaby 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: move ldisc data from tty_struct: locks

2012-10-22T23:53:01+00:00

atomic_write_lock is not n_tty specific, so move it up in the
tty_struct.

And since these are the last ones to move, remove also the comment
saying there are some ldisc' members. There are none now.

Signed-off-by: Jiri Slaby 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: move ldisc data from tty_struct: read_* and echo_* and canon_* stuff

2012-10-22T23:53:01+00:00

All the ring-buffers...

Signed-off-by: Jiri Slaby 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman