This patch (as1290) adds some missing tests.  serial_down() isn't
supposed to do anything if the hardware hasn't been initialized, and
serial_close() isn't supposed to do anything if the tty has gotten a
hangup (because serial_hangup() takes care of shutting down the
hardware).

The patch also updates and adds a few debugging lines.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1289) renames serial_do_down() to serial_down() and
serial_do_free() to serial_release().  It also adds a missing call to
tty_shutdown() in serial_release().
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1288) fixes the initialization logic in
serial_install().  A new tty always needs to have a termios
initialized no matter what, not just in the case where the lower
driver will override the termios settings.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1287) makes serial_install() be reponsible for acquiring
references to the usb_serial structure and the driver module when a
tty is first used.  This is more sensible than having serial_open() do
it, because a tty can be opened many times whereas it is installed
only once, when it is created.  (Not to mention that these actions are
reversed when the tty is released, not when it is closed.)  Finally,
it is at install time that the TTY core takes its own reference to the
usb_serial module, so it is only fitting that we should act the same
way in regard to the lower-level serial driver.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1286) changes usb_serial_get_by_index().  Now the
routine will check whether the serial device has been disconnected; if
it has then the return value will be NULL.  If the device hasn't been
disconnected then the routine will return with serial->disc_mutex
held, so that the caller can use the structure without fear of racing
against driver unloads.

This permits the scope of table_mutex in destroy_serial() to be
reduced.  Instead of protecting the entire function, it suffices to
protect the part that actually uses serial_table[], i.e., the call to
return_serial().  There's no longer any danger of the refcount being
incremented after it reaches 0 (which was the reason for having the
large scope previously), because it can't reach 0 until the serial
device has been disconnected.

Also, the patch makes serial_install() check that serial is non-NULL
before attempting to use it.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1285) rearranges the subroutines in usb-serial.c
concerned with tty lifetimes into a more logical order: install, open,
hangup, close, release.  It also updates the formatting of the
kerneldoc comments.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1284) changes the referencing of the usb_serial and
usb_serial_port structures in usb-serial.c.  It's not feasible to make
the port structures keep a reference to the serial structure, because
the ports need to remain in existence when serial is released -- quite
a few of the drivers expect this.  Consequently taking a reference
to the port when the device file is open is insufficient; such a
reference would not pin serial.

To fix this, we now take a reference to serial when the device file is
opened.  The final put_device() for the ports occurs in
destroy_serial(), so that the ports will last as long as they are
needed.

The patch initializes all the port devices, including those in the
unused "fake" ports.  This makes the code more uniform because they
can all be released in the same way.  The error handling code in
usb_serial_probe() is much simplified by this approach; instead of
freeing everything by hand we can use a single usb_serial_put() call.

Also simplified is the port-release mechanism.  Instead of being two
separate routines, port_release() and port_free() can be combined into
one.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Various drivers have hacks to mangle termios structures. This stems from
the fact there is no nice setup hook for configuring the termios settings
when the port is created
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

And indeed none of them use it. Clean this up as it will make moving to a
standard open method rather easier.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The USB layer uses tty_hangup to deal with unplugs of the physical hardware
(analogous to loss of carrier) and then frees the resources. However the
tty_hangup is asynchronous. As the hangup can sleep we can use tty_vhangup
which is the non async version to avoid freeing resources too early.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This fixes
- locking bug that was hidden by ecc2e05e
- Regression #13821
- Spurious warning when closing and blocking for data write out

With these changes my PL2303 always ends up as ttyUSB0 when it should and
the module refcounts stay correct.

I'll do a more wholesale split & tidy of _open in the next release or two
as we get a standard tty_port_open and port->ops->init port->ops->shutdown
call backs.

Copy sent to Alan Stern and Carlos Mafra just to confirm it fixes all the
reports but it passes local testing with the same hardware as Alan Stern.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The port lock is used to protect the port state. However the port structure
is freed on a hangup, then the lock taken on a close. The right fix is to
drop the port on tty->shutdown() but we can't yet do that due to sleep v
non-sleeping rules. Instead do the next best thing and fix it up when we are
not in -rc season.
Reported-by: NDaniel Mack <daniel@caiaq.de>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Tested-by: NDaniel Mack <daniel@caiaq.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The commit 335f8514 introduced a
regression which stopped usb consoles from working correctly as a
kernel boot console as well as interactive login device.

The addition of the serial_close() which in turn calls
tty_port_close_start() will change the reference count of port.count
and warn about it.  The usb console code had previously incremented
the port.count to indicate it was making use of the device as a
console and the forced change causes a double open on the usb device
which leads to a non obvious kernel oops later on when the tty is
freed.

To fix the problem instead make use of port->console to track if the
port is in fact an active console port to avoid double initialization
of the usb serial device.  The port.count is incremented and
decremented only with in the scope of usb_console_setup() for the
purpose of the low level driver initialization.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

* 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: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit 335f8514 has stopped
properly checking if there is any usb serial associated with the tty in
the close function. It happens the close function is called by releasing
the terminal right after opening the device fails.

As an example, open fails with a non-existing device, when probe has
never been called, because the device has never been plugged. This is
common in systems with static modules and no udev.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch (as1254) splits up the shutdown method of usb_serial_driver
into a disconnect and a release method.

The problem is that the usb-serial core was calling shutdown during
disconnect handling, but drivers didn't expect it to be called until
after all the open file references had been closed.  The result was an
oops when the close method tried to use memory that had been
deallocated by shutdown.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1253) prevents the usb-serial core from calling a
driver's port_probe and port_remove methods more than once per port.
It also removes some unnecessary try_module_get() calls and adds a
missing port_remove method call in a failure path.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This allows us to clean stuff up, but is probably also going to cause
some app breakage with buggy apps as we now implement proper POSIX behaviour
for USB ports matching all the other ports. This does also mean other apps
that break on USB will now work properly.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch (as1244) fixes a crash in usb-serial that occurs when a
sub-driver returns a positive value from its attach method, indicating
that new firmware was loaded and the device will disconnect and
reconnect.  The usb-serial core then skips the step of registering the
port devices; when the disconnect occurs, the attempt to unregister
the ports fails dramatically.

This problem shows up with Keyspan devices and it might affect others
as well.

When the attach method returns a positive value, the patch sets
num_ports to 0.  This tells usb_serial_disconnect() not to try
unregistering any of the ports; instead they are cleaned up by
destroy_serial().
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1229) fixes a few lifetime and locking problems in the
usb-serial driver.  The main symptom is that an invalid kevent is
created when the serial device is unplugged while a connection is
active.

	Ports should be unregistered when device is disconnected,
	not when the parent usb_serial structure is deallocated.

	Each open file should hold a reference to the corresponding
	port structure, and the reference should be released when
	the file is closed.

	serial->disc_mutex should be acquired in serial_open(), to
	resolve the classic race between open and disconnect.

	serial_close() doesn't need to hold both serial->disc_mutex
	and port->mutex at the same time.

	Release the subdriver's module reference only after releasing
	all the other references, in case one of the release routines
	needs to invoke some code in the subdriver module.

	Replace a call to flush_scheduled_work() (which is prone to
	deadlocks) with cancel_work_sync().  Also, add a call to
	cancel_work_sync() in the disconnect routine.

	Reduce the scope of serial->disc_mutex in serial_disconnect().
	The only place it really needs to protect is where the
	"disconnected" flag is set.

This fixes the bug reported in

	http://bugs.freedesktop.org/show_bug.cgi?id=20703Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NDan Williams <dcbw@redhat.com>
Tested-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NOliver Neukum <oliver@neukum.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With "nousb" cmdline booting, built-in serial drivers (ie. airecable)
will trigger kernel oops.

Indeed, if nousb, usb_serial_init will failed, and the usb serial bus type
will not be registerd, then usb_serial_register call driver_register
which try to register the driver to a not registered bus.

Here add usb_disabled() check in usb_serial_register to fix it.
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

A USB-serial converter device is plugged into a system, and a process
opens it's device node.  If the device is physically removed whilst the
process still has its device node open, then other processes can
sucessfully open the now non-existent device's node.  I would expect
that open() on a device that has been physically removed should return
ENODEV.

This is manifesting itself with getty on my system.  I do the following:
1.  set up inittab to spawn getty on ttyUSB0, eg:
    T1:23:respawn:/sbin/getty -L ttyUSB0 115200 vt100
2.  Plug in USB-serial converter cable
3.  Wait for a login prompt on a terminal program attached to the serial
    cable
4.  Login
5.  Pull the USB-serial converter cable from the box
6.  getty doesn't realise that ttyUSB0 no longer exists as /dev/ttyUSB0
    can still be opened.
7.  Re-insert the USB-serial converter cable
8.  You should no longer get a login prompt over the serial cable, as
    the the USB-serial cable now shows up as /dev/ttyUSB1, and getty is
    trying to talk to /dev/ttyUSB0.

The attached patch will cause open("/dev/ttyUSB0", O_RDONLY) to return
ENODEV after the USB-serial converter has been pulled.  The patch was
created against 2.6.28.1.  I can supply it against something else if
needs be.  It is fairly simple, so should be OK.

I am using a pl2303 device, although I don't think that makes any
difference.


From: James Woodcock <James.Woodcock@ACULAB.COM>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This removes the fallback to the generic method. It is cleaner to
explicitely request it. Introducing this was my mistake. This will
be solved by an explicit test and the driver being allowed to request
what it needs to be done upon resumption.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch makes use of the generic method if a serial driver provides
no implementation. This simplifies implementing suspend/resume support
in serial drivers.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

USB: serial: introduce a flag into the usb serial layer to tell drivers that their URBs are killed due to suspension

This patch introduces a flag into the usb serial layer to tell drivers
that their URBs are killed due to suspension. That is necessary to let
drivers know whether they should report an error back.
Signed-off-by: NOliver Neukum <oneukum@suse.de>

Hi Greg,

this is for 2.6.30. Patches to use this in drivers are under development.

	Regards
		Oliver

Julia Lawell found a case where a NULL check was misplaced in the
usb-serial code. However as the object in question cannot be NULL the
check can simply be removed.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We don't need the BKL here any more so it can go. In a couple of spots the
driver requirements are not clear so push the lock down into the driver.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The underlying problem is that the device methods don't all correctly
handle disconnected status and some keep reporting bytes pending which
causes tcdrain to stall.

When the cable is unplugged they are definitely gone, and as this is true
for all USB cables we can fix it in the core usb serial code.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

USB serial has always had races where the tty port usage count can hit zero
during a receive event. The internal locking is a mutex so we can't use
that in the IRQ handlers.

With krefs we can tackle this differently but we still need to be careful.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we close we must clear the extra reference we got when we read
port->tty. Setting the port tty NULL will clear the kref held by the driver
but not the one we obtained ourselves while doing the lookup.
Signed-off-by: NAlan Cox <alan@redhat.com>
Tested-by: NHelge Hafting <helge.hafting@aitel.hist.no>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

err() is going away, so switch to dev_err() or printk() if it's really
needed.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

USB should not be having it's own printk macros, so remove info() and
use the system-wide standard of dev_info() wherever possible.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.

Contains two err->dev_err changes merged together to fix clashes in the
-next tree.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This hardware needs the pl2303 hack in order to work properly :(
Signed-off-by: NAndreas Bombe <aeb@debian.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1121) fixes a bug in the USB serial core.  When a device
is unregistered, the core will give back its minors -- even if the
device hasn't been assigned any!

The patch reserves the highest minor value (255) to mean that no minor
was assigned.  It also removes some dead code and does a small style
fixup.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

USB serial likes to use port->tty back pointers for the real work it does and
to do so without any actual locking. Unfortunately when you consider hangup
events, hangup/parallel reopen or even worse hangup followed by parallel close
events the tty->port and port->tty pointers are not guaranteed to be the same
as port->tty is the active tty while tty->port is the port the tty may or
may not still be attached to.

So rework the entire API to pass the tty struct. For console cases we need
to pass both for now. This shows up multiple drivers that immediately crash
with USB console some of which have been fixed in the process.

Longer term we need a proper tty as console abstraction
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>