Commit Graph

31 Commits

Author SHA1 Message Date
Peter Hurley e359a4e38d tty: Remove tty_hung_up_p() tests from tty drivers' open()
Since at least before 2.6.30, it has not been possible to observe
a hung up file pointer in a tty driver's open() method unless/until
the driver open() releases the tty_lock() (eg., before blocking).

This is because tty_open() adds the file pointer while holding
the tty_lock() _and_ doesn't release the lock until after calling
the tty driver's open() method. [ Before tty_lock(), this was
lock_kernel(). ]

Since __tty_hangup() first waits on the tty_lock() before
enumerating and hanging up the open file pointers, either
__tty_hangup() will wait for the tty_lock() or tty_open() will
not yet have added the file pointer. For example,

CPU 0                          |  CPU 1
                               |
tty_open                       |  __tty_hangup
  ..                           |    ..
  tty_lock                     |    ..
  tty_reopen                   |    tty_lock  / blocks
  ..                           |
  tty_add_file(tty, filp)      |
  ..                           |
  tty->ops->open(tty, filp)    |
    tty_port_open              |
      tty_port_block_til_ready |
        ..                     |
        while (1)              |
          ..                   |
          tty_unlock           |    / unblocks
          schedule             |    for each filp on tty->tty_files
                               |      f_ops = tty_hung_up_fops;
                               |    ..
                               |    tty_unlock
          tty_lock             |
  ..                           |
  tty_unlock                   |

Note that since tty_port_block_til_ready() and similar drop
the tty_lock while blocking, when woken, the file pointer
must then be tested for having been hung up.

Also, fix bit-rotted drivers that used extra_count to track the
port->count bump.

CC: Mikael Starvik <starvik@axis.com>
CC: Samuel Ortiz <samuel@sortiz.org>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-10 16:06:49 -07:00
Salva Peiró b19a47e060 synclink: fix info leak in ioctl
The hdlcdev_ioctl() code fails to initialize the two padding bytes of
struct sync_serial_settings after the ->loopback member. Add an explicit
memset(0) before filling the structure to avoid the info leak.

Signed-off-by: Salva Peiró <speiro@ai2.upv.es>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-03-17 16:13:23 -07:00
Arnd Bergmann b8c98ae49e tty: synclink: avoid sleep_on race
The four variants of the synclink driver use the same code in their
open() callback to wait for a port in process of being closed,
using interruptible_sleep_on, which is racy and going away soon.

Making things worse, these functions hold the BTM while doing so,
which means that if we ever enter this code path, we cannot actually
continue since the other thread that is in process of closing the
port can no longer get the BTM.

This addresses both issues by using wait_event_interruptible_tty()
instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-07 17:05:21 -08:00
Alexandru Juncu e06922aa83 TTY: synclink: replace bitmasks add operation with OR operation.
Found with coccinelle, manually fixed and verified.

Signed-off-by: Alexandru Juncu <alexj@rosedu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-29 12:47:37 -07:00
Johan Hovold 78c6cccadb TTY: synclink: fix DTR being raised on hang up
Make sure to check ASYNC_INITIALISED before raising DTR when waking up
from blocked open in block_til_ready.

Currently DTR could get raised at hang up as a blocked process would
raise DTR unconditionally before checking for hang up and returning.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-12 14:08:17 -07:00
Jiri Slaby 049b539b39 TTY: synclink, remove superfluous check
info is obtained by container_of. It can never be NULL. So do not test
that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:17:20 -07:00
Joe Perches 9fe8074b82 TTY: synclink: Convert + to | for bit operations
Dan Carpenter noticed a missing set of parentheses
around a multiple field addition.

https://lkml.org/lkml/2013/1/27/166

His original commit message:

There is a kind of precedence problem here, but it doesn't affect how
the code works because ->serial_signals is unsigned char.  We want to
clear two flags here.

#define SerialSignal_RTS            0x20     /* Request to Send */
#define SerialSignal_DTR            0x80     /* Data Terminal Ready */

Without the parenthesis then it does:

	info->serial_signals &= 0x5f;

With the parenthesis it does:

	info->serial_signals &= 0xffffff5f;

info->serial_signals is an unsigned char so the two statements are
equivalent, but it's cleaner to add the parenthesis.  In other dtr_rts()
functions the parenthesis are there so this makes it more consistent.

Other changes:

Convert all + uses to | for these bit operations.

Reorder the multiple fields for consistency.
Update the comments too.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-30 00:09:58 -05:00
Jiri Slaby 2e124b4a39 TTY: switch tty_flip_buffer_push
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-15 22:30:15 -08:00
Jiri Slaby d6c53c0e9b TTY: move low_latency to tty_port
One point is to have less places where we actually need tty pointer.
The other is that low_latency is bound to buffer processing and
buffers are now in tty_port. So it makes sense to move low_latency to
tty_port too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-15 22:23:16 -08:00
Jiri Slaby 92a19f9cec TTY: switch tty_insert_flip_char
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

tty_insert_flip_char is the next one to proceed. This one is used all
over the code, so the patch is huge.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-15 22:21:36 -08:00
Paul Fulghum a6b68a69fa synclink fix ldisc buffer argument
Fix call to line discipline receive_buf by synclink drivers.
Dummy flag buffer argument is ignored by N_HDLC line discipline but might
be of insufficient size if accessed by a different line discipline
selected by mistake. flag buffer allocation now matches max size of data
buffer. Unused char_buf buffers are removed.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-15 21:52:23 -08:00
Bill Pemberton ae8d8a1467 tty: remove use of __devexit
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-21 15:27:46 -08:00
Bill Pemberton 9671f09921 tty: remove use of __devinit
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-21 15:22:52 -08:00
Bill Pemberton 91116cba5d tty: remove use of __devexit_p
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-21 15:19:52 -08:00
Jiri Slaby 191c5f1027 TTY: call tty_port_destroy in the rest of drivers
After commit "TTY: move tty buffers to tty_port", the tty buffers are
not freed in some drivers. This is because tty_port_destructor is not
called whenever a tty_port is freed. This was an assumption I counted
with but was unfortunately untrue. So fix the drivers to fulfil this
assumption.

To be sure, the TTY buffers (and later some stuff) are gone along with
the tty_port, we have to call tty_port_destroy at tear-down places.
This is mostly where the structure containing a tty_port is freed.
This patch does exactly that -- put tty_port_destroy at those places.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-15 17:20:58 -08:00
Huang Shijie f21ec3d2d4 serial: add a new helper function
In most of the time, the driver needs to check if the cts flow control
is enabled. But now, the driver checks the ASYNC_CTS_FLOW flag manually,
which is not a grace way. So add a new wraper function to make the code
tidy and clean.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-05 13:28:35 -07:00
Jiri Slaby 8a3ad10475 TTY: synclink, add tty install
This has two outcomes:
* we give the TTY layer a tty_port
* we do not find the info structure every time open is called on that
  tty

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>
2012-08-13 16:53:13 -07:00
Alan Cox 89c8d91e31 tty: localise the lock
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>
2012-08-10 12:55:47 -07:00
Alan Cox adc8d746ca tty: move the termios object into the tty
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>
2012-07-16 13:00:41 -07:00
Alan Cox 6d31a88cb2 tty: revert incorrectly applied lock patch
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>
2012-07-16 12:58:12 -07:00
Alan Cox f5e3bcc504 tty: localise the lock
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>
2012-07-06 14:24:52 -07:00
Linus Torvalds f309532bf3 tty: Revert the tty locking series, it needs more work
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>
2012-06-02 15:21:43 -07:00
Alan Cox d29f3ef39b tty_lock: Localise the lock
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>
2012-05-04 16:58:47 -07:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
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>
2012-03-28 18:30:03 +01:00
Jiri Slaby 410235fd4d TTY: remove unneeded tty->index checks
Checking if tty->index is in bounds is not needed. The tty has the
index set in the initial open. This is done in get_tty_driver. And it
can be only in interval <0,driver->num).

So remove the tests which check exactly this interval. Some are
left untouched as they check against the current backing device count.
(Leaving apart that the check is racy in most of the cases.)

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08 11:42:21 -08:00
Jiri Slaby 2f16669d32 TTY: remove re-assignments to tty_driver members
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>
2012-03-08 11:37:58 -08:00
Rusty Russell 90ab5ee941 module_param: make bool parameters really bool (drivers & misc)
module_param(bool) used to counter-intuitively take an int.  In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option.  For this version
it'll simply give a warning, but it'll break next kernel version.

Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-13 09:32:20 +10:30
Edwin van Vliet ae8dbd3eb9 drivers/tty/synclink: remove double comment
Redundant comment line was removed

Signed-off-by: Edwin van Vliet <edwin@cheatah.nl>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-23 10:32:56 -07:00
Jovi Zhang 99edb3d10a tty: remove invalid location line in file header
remove invalid location line in each file header after location
moved from driver/char to driver/tty

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:33:36 -07:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Greg Kroah-Hartman a6afd9f3e8 tty: move a number of tty drivers from drivers/char/ to drivers/tty/
As planned by Arnd Bergmann, this moves the following drivers from
drivers/char/ to drivers/tty/ as that's where they really belong:
	amiserial
	nozomi
	synclink
	rocket
	cyclades
	moxa
	mxser
	isicom
	bfin_jtag_comm

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-22 16:14:56 -08:00