linux-stable.git/drivers/tty/pty.c, branch v3.5 Linux kernel stable tree tty: Revert the tty locking series, it needs more work 2012-06-02T22:21:43+00:00 Linus Torvalds torvalds@linux-foundation.org 2012-06-02T22:21:43+00:00 f309532bf3e1cc1b787403d84e3039812a7dbe50 This reverts the tty layer change to use per-tty locking, because it's not correct yet, and fixing it will require some more deep surgery. The main revert is d29f3ef39be4 ("tty_lock: Localise the lock"), but there are several smaller commits that built upon it, they also get reverted here. The list of reverted commits is: fde86d310886 - tty: add lockdep annotations 8f6576ad476b - tty: fix ldisc lock inversion trace d3ca8b64b97e - pty: Fix lock inversion b1d679afd766 - tty: drop the pty lock during hangup abcefe5fc357 - tty/amiserial: Add missing argument for tty_unlock() fd11b42e3598 - cris: fix missing tty arg in wait_event_interruptible_tty call d29f3ef39be4 - tty_lock: Localise the lock The revert had a trivial conflict in the 68360serial.c staging driver that got removed in the meantime. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This reverts the tty layer change to use per-tty locking, because it's
not correct yet, and fixing it will require some more deep surgery.

The main revert is d29f3ef39be4 ("tty_lock: Localise the lock"), but
there are several smaller commits that built upon it, they also get
reverted here. The list of reverted commits is:

  fde86d310886 - tty: add lockdep annotations
  8f6576ad476b - tty: fix ldisc lock inversion trace
  d3ca8b64b97e - pty: Fix lock inversion
  b1d679afd766 - tty: drop the pty lock during hangup
  abcefe5fc357 - tty/amiserial: Add missing argument for tty_unlock()
  fd11b42e3598 - cris: fix missing tty arg in wait_event_interruptible_tty call
  d29f3ef39be4 - tty_lock: Localise the lock

The revert had a trivial conflict in the 68360serial.c staging driver
that got removed in the meantime.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pty: Fix lock inversion 2012-05-29T17:42:13+00:00 Alan Cox alan@linux.intel.com 2012-05-29T12:45:01+00:00 d3ca8b64b97ef4dc54d7bb0b88bbc01a1fca8cb9 The ptmx_open path takes the tty and devpts locks in the wrong order because tty_init_dev locks and returns a locked tty. As far as I can tell this is actually safe anyway because the tty being returned is new so nobody can get a reference to lock it at this point. However we don't even need the devpts lock at this point, it's only held as a byproduct of the way the locks were pushe down. Signed-off-by: Alan Cox <alan@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The ptmx_open path takes the tty and devpts locks in the wrong order
because tty_init_dev locks and returns a locked tty.  As far as I can
tell this is actually safe anyway because the tty being returned is new
so nobody can get a reference to lock it at this point.

However we don't even need the devpts lock at this point, it's only held
as a byproduct of the way the locks were pushe down.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
tty: drop the pty lock during hangup 2012-05-09T21:40:27+00:00 Alan Cox alan@linux.intel.com 2012-05-09T16:03:19+00:00 b1d679afd766cf425ba1cd2a0fd17451bd212f4a In theory we don't need it, in practice we are hitting some ill understood deadlock when we don't drop it. The old code dropped it here so we are not undoing anything problematic for pty. If pty could be unloaded it would be a problem but it can't. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
In theory we don't need it, in practice we are hitting some ill understood
deadlock when we don't drop it. The old code dropped it here so we are not
undoing anything problematic for pty. If pty could be unloaded it would be
a problem but it can't.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_lock: Localise the lock 2012-05-04T23:58:47+00:00 Alan Cox alan@linux.intel.com 2012-05-03T21:24:08+00:00 d29f3ef39be4eec0362b985305fc526d9be318cf In each remaining case the tty_lock is associated with a specific tty. This means we can now lock on a per tty basis. We do need tty_lock_pair() for the pty case. Uglier but still a step in the right direction. [fixed up calls in 3 missing drivers - gregkh] Signed-off-by: Alan Cox <alan@linux.intel.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
In each remaining case the tty_lock is associated with a specific tty. This
means we can now lock on a per tty basis. We do need tty_lock_pair() for
the pty case. Uglier but still a step in the right direction.

[fixed up calls in 3 missing drivers - gregkh]

Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pty: Lock the devpts bits privately 2012-05-04T23:48:37+00:00 Alan Cox alan@linux.intel.com 2012-05-03T21:22:09+00:00 d739e65bb21d34f0f5d3bf4048410e534fbec148 This is a private pty affair, we don't want to tangle it with the tty_lock any more as we know all the other non tty locking is now handled by the vfs so we too can move. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This is a private pty affair, we don't want to tangle it with the tty_lock
any more as we know all the other non tty locking is now handled by the vfs
so we too can move.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove all #inclusions of asm/system.h 2012-03-28T17:30:03+00:00 David Howells dhowells@redhat.com 2012-03-28T17:30:03+00:00 9ffc93f203c18a70623f21950f1dd473c9ec48cd Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com> 
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
TTY: remove re-assignments to tty_driver members 2012-03-08T19:37:58+00:00 Jiri Slaby jslaby@suse.cz 2012-03-05T13:51:52+00:00 2f16669d322e05171c9e1cfd94f402f7399bd2a3 All num, magic and owner are set by alloc_tty_driver. No need to re-set them on each allocation site. pti driver sets something different to what it passes to alloc_tty_driver. It is not a bug, since we don't use the lines parameter in any way. Anyway this is fixed, and now we do the right thing. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.

pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "TTY: pty, remove superfluous ptm test" 2012-02-24T21:56:36+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2012-02-24T21:56:36+00:00 ce1000ddca01c81684da844be4676eac50a70c2a This reverts commit a50f724a432997321cabb6c9e665c28e34850f78. Sasha reported that this causes problems, so revert it. Cc: Alan Cox <alan@linux.intel.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit a50f724a432997321cabb6c9e665c28e34850f78.

Sasha reported that this causes problems, so revert it.

Cc: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "TTY: get rid of BTM around devpts_*" 2012-02-24T21:55:54+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2012-02-24T21:55:54+00:00 0ef1698e4d6282a1665207c40b115ec78fceda9b This reverts commit d3bda5298aad98c7a27678bdd0dd9d008ab9e685. Sasha reported that this causes problems, so revert it. Cc: Sasha Levin <levinsasha928@gmail.com> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit d3bda5298aad98c7a27678bdd0dd9d008ab9e685.

Sasha reported that this causes problems, so revert it.

Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY: get rid of BTM around devpts_* 2012-02-02T23:10:46+00:00 Jiri Slaby jslaby@suse.cz 2012-01-30T20:14:32+00:00 d3bda5298aad98c7a27678bdd0dd9d008ab9e685 devpts operations are protected by inode mutexes and dentry refcounting. There is no need to hold BTM. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
devpts operations are protected by inode mutexes and dentry
refcounting. There is no need to hold BTM.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>