litmus-rt.git/drivers/char/n_hdlc.c, branch 2010.2

headers: smp_lock.h redux

2009-07-12T19:22:34+00:00

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Linus Torvalds

tty: n_hdlc add buffer flushing

2009-06-22T18:32:24+00:00

Add flush_buffer tty callback to flush rx buffers.
Add TCFLSH ioctl processing to flush tx buffers.
Increase default tx buffers from 1 to 3.
Remove unneeded flush_buffer call in open callback.
Remove vendor specific CVS version string.

Signed-off-by: Paul Fulghum 
Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

tty: rewrite the ldisc locking

2009-06-11T15:51:01+00:00

There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.

This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
  later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking

There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.

This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded

and probably a few other of the mysterious ldisc race reports.

I'm sure it also adds the odd new one.

Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

tty: some ICANON magic is in the wrong places

2008-10-13T16:51:44+00:00

Move the set up on ldisc change into the ldisc
Move the INQ/OUTQ cases into the driver not in shared ioctl code where it
gives bogus answers for other ldisc values

Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

n_hdlc: honor O_NONBLOCK on write

2008-07-22T20:03:28+00:00

Make n_hdlc line discipline honor the O_NONBLOCK file flag on write.

Signed-off-by: Paul Fulghum 
Signed-off-by: Andrew Morton 
Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

tty: Ldisc revamp

2008-07-21T00:12:34+00:00

Move the line disciplines towards a conventional ->ops arrangement.  For
the moment the actual 'tty_ldisc' struct in the tty is kept as part of
the tty struct but this can then be changed if it turns out that when it
all settles down we want to refcount ldiscs separately to the tty.

Pull the ldisc code out of /proc and put it with our ldisc code.

Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

tty: The big operations rework

2008-04-30T15:29:47+00:00

- Operations are now a shared const function block as with most other Linux
  objects

- Introduce wrappers for some optional functions to get consistent behaviour

- Wrap put_char which used to be patched by the tty layer

- Document which functions are needed/optional

- Make put_char report success/fail

- Cache the driver->ops pointer in the tty as tty->ops

- Remove various surplus lock calls we no longer need

- Remove proc_write method as noted by Alexey Dobriyan

- Introduce some missing sanity checks where certain driver/ldisc
  combinations would oops as they didn't check needed methods were present

[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox 
Acked-by: Greg Kroah-Hartman 
Cc: Jason Wessel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tty: BKL pushdown

2008-04-30T15:29:40+00:00

- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
  on the paths that historically held the lock

BKL now primarily protects open/close/ldisc change in the tty layer

[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: Alan Cox 
Signed-off-by: Jiri Slaby 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers: fix integer as NULL pointer warnings

2008-04-29T00:31:13+00:00

Signed-off-by: Harvey Harrison 
Signed-off-by: Linus Torvalds

n_hdlc.c: fix check-after-use

2007-10-17T15:42:55+00:00

The Coverity checker spotted that we'd have already oops'ed if "tty"
was NULL.

Since "tty" can't be NULL when we reach this line of code this patch
removes the NULL check.

Signed-off-by: Adrian Bunk 
Acked-by: Alan Cox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds