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 <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For that purpose we have to temporarily introduce a second tty back
pointer into tty_port. It is because serial layer, and maybe others,
still do not use tty_port_tty_set/get. So that we cannot set the
tty_port->tty to NULL at will now.
Yes, the fix would be to convert whole serial layer and all its users
to tty_port_tty_set/get. However we are in the process of removing the
need of tty in most of the call sites, so this would lead to a
duplicated work.
Instead we have now tty_port->itty (internal tty) which will be used
only in flush_to_ldisc. For that one it is ensured that itty is valid
wherever the work is run. IOW, the work is synchronously cancelled
before we set itty to NULL and also before hangup is processed.
After we need only tty_port and not tty_struct in most code, this
shall be changed to tty_port_tty_set/get and itty removed completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here we start moving all the n_tty related bits from tty_struct to
the newly defined n_tty_data struct in n_tty proper.
In this patch primitive members and bits are moved. The rest will be
done per-partes in the next patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have control over tty->driver_data in pty, we can just
kill the /dev/pts/ in pty code too. Namely, in ->shutdown hook of
tty. For pty, this is called only once, for whichever end is closed
last. But we don't care, both driver_data are the inode as it used to
be till now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull vfs update from Al Viro:
- big one - consolidation of descriptor-related logics; almost all of
that is moved to fs/file.c
(BTW, I'm seriously tempted to rename the result to fd.c. As it is,
we have a situation when file_table.c is about handling of struct
file and file.c is about handling of descriptor tables; the reasons
are historical - file_table.c used to be about a static array of
struct file we used to have way back).
A lot of stray ends got cleaned up and converted to saner primitives,
disgusting mess in android/binder.c is still disgusting, but at least
doesn't poke so much in descriptor table guts anymore. A bunch of
relatively minor races got fixed in process, plus an ext4 struct file
leak.
- related thing - fget_light() partially unuglified; see fdget() in
there (and yes, it generates the code as good as we used to have).
- also related - bits of Cyrill's procfs stuff that got entangled into
that work; _not_ all of it, just the initial move to fs/proc/fd.c and
switch of fdinfo to seq_file.
- Alex's fs/coredump.c spiltoff - the same story, had been easier to
take that commit than mess with conflicts. The rest is a separate
pile, this was just a mechanical code movement.
- a few misc patches all over the place. Not all for this cycle,
there'll be more (and quite a few currently sit in akpm's tree)."
Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
MAX_LFS_FILESIZE should be a loff_t
compat: fs: Generic compat_sys_sendfile implementation
fs: push rcu_barrier() from deactivate_locked_super() to filesystems
btrfs: reada_extent doesn't need kref for refcount
coredump: move core dump functionality into its own file
coredump: prevent double-free on an error path in core dumper
usb/gadget: fix misannotations
fcntl: fix misannotations
ceph: don't abuse d_delete() on failure exits
hypfs: ->d_parent is never NULL or negative
vfs: delete surplus inode NULL check
switch simple cases of fget_light to fdget
new helpers: fdget()/fdput()
switch o2hb_region_dev_write() to fget_light()
proc_map_files_readdir(): don't bother with grabbing files
make get_file() return its argument
vhost_set_vring(): turn pollstart/pollstop into bool
switch prctl_set_mm_exe_file() to fget_light()
switch xfs_find_handle() to fget_light()
switch xfs_swapext() to fget_light()
...
iterates through the opened files in given descriptor table,
calling a supplied function; we stop once non-zero is returned.
Callback gets struct file *, descriptor number and const void *
argument passed to iterator. It is called with files->file_lock
held, so it is not allowed to block.
tty_io, netprio_cgroup and selinux flush_unauthorized_files()
converted to its use.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Added tty_device_create_release() and bound to dev->release in
tty_register_device_attr().
Added tty_port_register_device_attr() and used in uart_add_one_port()
instead of tty_register_device_attr().
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.
tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At commit 07d106d0, Linus pointed out that ENOIOCTLCMD should be
translated as ENOTTY to user mode.
For example:
fd = open("/dev/tty", O_RDWR);
ioctl(fd, -1, &argp);
then the errno should be ENOTTY but not EINVAL.
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
And if not, complain loudly. None in-kernel module should trigger
that, but let us find out for sure. On the other hand, all the
out-of-tree modules will hit that. Give them some time (maybe one
release) to catch up.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the /dev/ node not to be available before we call
tty_register_device. Otherwise we might race with open and
tty_struct->port might not be available at that time.
This is not an issue now, but would be a problem after "TTY: use
tty_port_register_device" is applied.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This allows drivers like ttyprintk to avoid hacks to create an
unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in
flags and call device_create on its own. That is incorrect, because
TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is
called explicitly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
So now, that we have flags and know everything needed, keep a promise
and move all the tables and ports allocation from tty_register_driver
to tty_alloc_driver.
Not only that it makes sense, but we need this for
tty_port_link_device which needs tty_driver->ports but is to be called
before tty_register_driver.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to allow drivers that use neither tty_port_install nor
tty_port_register_device to link a tty_port to a tty somehow. To
avoid a race with open, this has to be performed before
tty_register_device. But currently tty_driver->ports is allocated even
in tty_register_device because we do not know whether this is the PTY
driver. The PTY driver is special here due to an excessive count of
lines it declares to handle. We cannot handle tty_ports there this
way.
To circumvent this, we start passing tty_driver flags to
alloc_tty_driver already and we create tty_alloc_driver for this
purpose. There we can allocate tty_driver->ports and do all the magic
between tty_alloc_driver and tty_register_device. Later we will
introduce tty_port_link_device function for that purpose.
All drivers should eventually switch to this new tty driver allocation
interface.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.
This contains pieces folded in from the fixes made to the original patches
| From: Geert Uytterhoeven <geert@linux-m68k.org> (fix m68k)
| From: Paul Gortmaker <paul.gortmaker@windriver.com> (fix cris)
| From: Jiri Kosina <jkosina@suze.cz> (lockdep)
| From: Eric Dumazet <eric.dumazet@gmail.com> (lockdep)
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We sometimes pass NULL pointers to free_tty_struct(). One example where
it can happen is in the error handling code in pty_common_install().
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We're trying to save the termios state and we need to allocate a buffer
to do it. Smatch complains that the buffer is leaked at the end of the
function.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott found that the tty layer would explode with the right set of
parallel open and close operations. This is because we race in the
handling of tty->drivers->termios[].
Correct this by
Making tty_ldisc_release behave like nromal code (takes the lock,
does stuff, drops the lock)
Drop the tty lock earlier in tty_ldisc_release
Taking the tty mutex around the driver->termios update in all cases
Adding a WARN_ON to catch future screwups.
I also forgot to clean up the pty resources properly. With a pty pair we
need to pull both halves out of the tables.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we don't have tty->termios tied to drivers->tty we can untangle
the logic here. In addition we can push the removal logic out of the
destructor path.
At that point we can think about sorting out tty_port and console and all
the other ugly hangovers.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.
This contains pieces folded in from the fixes made to the original patches
| From: Geert Uytterhoeven <geert@linux-m68k.org> (fix m68k)
| From: Paul Gortmaker <paul.gortmaker@windriver.com> (fix cris)
| From: Jiri Kosina <jkosina@suze.cz> (lockdep)
| From: Eric Dumazet <eric.dumazet@gmail.com> (lockdep)
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It will hold tty_port structures for all drivers which do not want to
define tty->ops->install hook.
We ignore PTY here because it wants 1 million lines and it installs
tty_port in ->install anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, some failures are handled in if's false branches, some at
the end of tty_register_driver via goto-labels. Let us handle the
failures at the end of the functions to have the failure handling at
a single place. The only thing needed is to label the lines properly
and jump there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 d29f3ef39b ("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:
fde86d3108 - tty: add lockdep annotations
8f6576ad47 - tty: fix ldisc lock inversion trace
d3ca8b64b9 - pty: Fix lock inversion
b1d679afd7 - tty: drop the pty lock during hangup
abcefe5fc3 - tty/amiserial: Add missing argument for tty_unlock()
fd11b42e35 - cris: fix missing tty arg in wait_event_interruptible_tty call
d29f3ef39b - 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>
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>
get_current_tty has its own consistent locking. That means a pile of the
tty lock cases are not needed. As get_current_tty also keeps a reference the
tty object lifetime means we can propogate the lock removal out.
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 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>
This is from tty_reopen:
struct tty_driver *driver = tty->driver;
...
tty->driver = driver;
and it doesn't make sense at all. The driver is intended to be set in
initialize_tty_struct from tty_init_dev (initial open). So this set in
tty_reopen is not needed.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the useless local variable and return the value itself.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Like the rest of the kernel, make a stub from alloc_tty_driver which
calls __alloc_tty_driver with proper owner. This will save us one more
assignment on the driver side.
Also this fixes some drivers which didn't set the owner. This allowed
user to remove the module from the system even though a tty from the
driver is still open.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY buffer head and tail are initialized in tty_buffer_init. No need
to do it once again in initialize_tty_struct where tty_buffer_init is
called.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit d3bda5298a.
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>
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>
There are currently many cut&paste copies of what
tty_driver_install_tty does when custom ->install method is not
provided. Let's get rid of the copies and create a helper with this
setup code.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Havard Skinnemoen <hskinnemoen@google.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cleanup hack added in v2.6.27-3203-g15582d3
comment from that patch:
: pty: If the administrator creates a device for a ptmx slave we should not error
:
: The open path for ptmx slaves is via the ptmx device. Opening them any
: other way is not allowed. Vegard Nossum found that previously this was not
: the case and mknod foo c 128 42; cat foo would produce nasty diagnostics
:
: Signed-off-by: Alan Cox <alan@redhat.com>
: Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devpts_get_tty() returns non-null only for inodes on devpts, but there is no
inodes for master-devices, /dev/ptmx (/dev/pts/ptmx) is the only way to open them.
Thus we can completely forbid lookup for master-devices and eliminate that hack in
tty_init_dev() because tty_open() will get EIO from tty_driver_lookup_tty().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (65 commits)
tty: serial: imx: move del_timer_sync() to avoid potential deadlock
imx: add polled io uart methods
imx: Add save/restore functions for UART control regs
serial/imx: let probing fail for the dt case without a valid alias
serial/imx: propagate error from of_alias_get_id instead of using -ENODEV
tty: serial: imx: Allow UART to be a source for wakeup
serial: driver for m32 arch should not have DEC alpha errata
serial/documentation: fix documented name of DCD cpp symbol
atmel_serial: fix spinlock lockup in RS485 code
tty: Fix memory leak in virtual console when enable unicode translation
serial: use DIV_ROUND_CLOSEST instead of open coding it
serial: add support for 400 and 800 v3 series Titan cards
serial: bfin-uart: Remove ASYNC_CTS_FLOW flag for hardware automatic CTS.
serial: bfin-uart: Enable hardware automatic CTS only when CTS pin is available.
serial: make FSL errata depend on 8250_CONSOLE, not just 8250
serial: add irq handler for Freescale 16550 errata.
serial: manually inline serial8250_handle_port
serial: make 8250 timeout use the specified IRQ handler
serial: export the key functions for an 8250 IRQ handler
serial: clean up parameter passing for 8250 Rx IRQ handling
...
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There is no need to taint the tty_release code with paranoia
checking. So move it out of line to a separate function. Making thus
tty_release more readable.
[v2] don't introduce a hard to reproduce use after free (scheduled work would
need to preempt the current thread)
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The labels express more the nature of the decision tree. We returned
from each if with a driver. Now we do this at the end of the function
and the code flow is clear.
While at it, remove an obsolete comment (we already take the
reference).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move them to the end of the function and use gotos as usual.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The error handling in tty_open became unbearable. There were many
errors fixed recently. Extract the tty driver lookup from tty_open to
a separate function. This reduces the fail paths significantly and
makes tty_open more readable.
In the next patch we will move the fail path handling to the end of
the function.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This one is special to others (done in the next patch). We have the
tty directly, not its driver and index. So this will reside in a
separation function. In the next patch, the rest will be moved to
another function.
So now we set neither driver nor index. Hence we need to init driver
and check whether we are supposed to put a ref of that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move it to the only branch where tty_pgrp may be set. This is only a
cleanup which allows having tty_pgrp defined at that place.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (79 commits)
TTY: serial_core: Fix crash if DCD drop during suspend
tty/serial: atmel_serial: bootconsole removed from auto-enumerates
Revert "TTY: call tty_driver_lookup_tty unconditionally"
tty/serial: atmel_serial: add device tree support
tty/serial: atmel_serial: auto-enumerate ports
tty/serial: atmel_serial: whitespace and braces modifications
tty/serial: atmel_serial: change platform_data variable name
tty/serial: RS485 bindings for device tree
TTY: call tty_driver_lookup_tty unconditionally
TTY: pty, release tty in all ptmx_open fail paths
TTY: make tty_add_file non-failing
TTY: drop driver reference in tty_open fail path
8250_pci: Fix kernel panic when pch_uart is disabled
h8300: drivers/serial/Kconfig was moved
parport_pc: release IO region properly if unsupported ITE887x card is found
tty: Support compat_ioctl get/set termios_locked
hvc_console: display printk messages on console.
TTY: snyclinkmp: forever loop in tx_load_dma_buffer()
tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output
tty/n_gsm: fix a bug in gsm_dlci_data_output (adaption = 2 case)
...
Fix up Conflicts in:
- drivers/tty/serial/8250_pci.c
Trivial conflict with removed duplicate device ID
- drivers/tty/serial/atmel_serial.c
Annoying silly conflict between "specify the port num via
platform_data" and other changes to atmel_console_init
Commit 4a2b5fddd5 (Move tty lookup/reopen to caller) made the call to
tty_driver_lookup_tty conditional in tty_open. It doesn't look like it
was an intention. Or if it was, it was not documented in the changelog
and the code now looks weird. For example there would be no need to
remember the tty driver and tty index. Further the condition depends
on a tty which we drop a reference of already.
If I'm looking correctly, this should not matter thanks to the locking
currently done there. Thus, tty_driver->ttys[idx] cannot change under
our hands. But anyway, it makes sense to change that to the old
behaviour.
Introduced-in: v2.6.28-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
