Commit Graph

8 Commits

Author SHA1 Message Date
Alan Cox 852e99d22f tty: bring ldisc into CodingStyle
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox f2c4c65c83 tty: Move ldisc_flush
We have a tty_ldisc file now so put tty_ldisc_flush in the right place

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox c65c9bc3ef tty: rewrite the ldisc locking
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 <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox e8b70e7d3e tty: Extract various bits of ldisc code
Before trying to tackle the ldisc bugs the code needs to be a good deal
more readable, so do the simple extractions of routines first.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Al Viro e5824c97a9 Trim includes of fdtable.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31 23:00:28 -04:00
Alan Cox c9b3976e3f tty: Fix PPP hang under load
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 10:19:38 -08:00
Eugeniy Meshcheryakov 3ab36ab685 try harder to load tty ldisc driver
Currently function tty_ldisc_get() tries to load an ldisc driver module
only when tty_ldisc_try_get() returns -EAGAIN. This happens only if
module is being unloaded. If ldisc module is not loaded
tty_ldisc_try_get() returns -EINVAL and this case is not handled in
tty_ldisc_get(), so request_module() is not called.

Attached patch fixes this by calling request_module() if
tty_ldisc_try_get() returned any error code.

I discovered this when my UMTS modem stopped working with 2.6.27-rc1
because module ppp_async was not loaded.

Signed-off-by: Eugeniy Meshcheryakov <eugen@debian.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-01 12:50:15 -07:00
Alan Cox 01e1abb2c2 tty: Split ldisc code into its own file
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-22 13:03:27 -07:00