The design of uplink flow control in the mux driver is
that for constipated channels data will backup into the
per-channel fifos, and any messages that make it to the
outbound message queue will still go out.
Code was added to also stop messages that were in the outbound
queue but this requires filtering through all the messages on the
queue for stopped dlcis and changes some of the mux logic unneccessarily.

The message fiiltering was removed to be in line w/ the original design
as the message filtering does not provide any solution.
Extra debug messages used during investigation were also removed.
Signed-off-by: Nsamix.lebsir <samix.lebsir@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: Dressage <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

- Correcting handling of FCon/FCoff in order to respect 27.010 spec
- Consider FCon/off will overide all dlci flow control except for
  dlci0 as we must be able to send control frames.
- Dlci constipated handling according to FC, RTC and RTR values.
- Modifying gsm_dlci_data_kick and gsm_dlci_data_sweep according
  to dlci constipated value
Signed-off-by: NFrederic Berat <fredericx.berat@intel.com>
Signed-off-by: NRuss Gorby <russ.gorby@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

gsm_dlci_data_kick will not call any output function if tx_bytes > THRESH_LO
furthermore it will call the output function only once if tx_bytes == 0
If the size of the IP writes are on the order of THRESH_LO
we can get into a situation where skbs accumulate on the outbound list
being starved for events to call the output function.

gsm_dlci_data_kick now calls the sweep function when tx_bytes==0
Signed-off-by: NRuss Gorby <russ.gorby@intel.com>
Tested-by: NKappel, LaurentX <laurentx.kappel@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: Hay and Water <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In 3GPP27.010 5.8.1, it defined:
The TE multiplexer initiates the establishment of the multiplexer control channel by sending a SABM frame on DLCI 0 using the procedures of clause 5.4.1.
Once the multiplexer channel is established other DLCs may be established using the procedures of clause 5.4.1.
This patch implement 5.8.1 in MUX level, it make sure DLC0 is the first channel to be setup.

[or for those not familiar with the specification: it was possible to try
 and open a data connection while the control channel was not yet fully
 open, which is a spec violation and confuses some modems]
Signed-off-by: Nxiaojin <jin.xiao@intel.com>
Tested-by: NYin, Fengwei <fengwei.yin@intel.com>
[tweaked the order we check things and error code]
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: The Horsebox <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Change the BUG_ON to WARN_ON and return in case of tty->read_buf==NULL. We want to track a
couple of long standing reports of this but at the same time we can avoid killing the box.
Signed-off-by: NStanislav Kozina <skozina@redhat.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: Horses <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAlan Cox <alan@linux.intel.com>
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=22502Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The changes in linux-next removing serial8250_register_port() cause
OCTEON to fail to compile.

Lets make OCTEON use the new serial8250_register_8250_port() instead.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit "TTY: synclink_cs, use dynamic tty devices" added a call to
tty_port_register_device with a proper device as the last argument.
But it was not correct and it causes build failures:
synclink_cs.c: In function ‘mgslpc_add_device’:
synclink_cs.c:2735:16: error: request for member ‘dev’ in something not a structure or union

info->p_dev is a pointer, so act as that.

I wonder why my build scripts did not notice. I have to re-check them.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

444 means 0674 and we do not definitely want that. Use S_IRUGO which
is much more safer.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Reported-by: NRusty Russell <rusty@ozlabs.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

>From now on, we only increase the reference count in ->install (and
decrease in ->cleanup).
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make the code of hvcs_open a bit more readable by:
- moving all assignments out of if's
- redoing fail paths so that corresponding pieces are nearby
- we need only one of retval and rc
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

Since we take a reference to a port in ->install, we need also
->cleanup to drop that reference.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

In this case ->install is the only thing we want to do. We do not need
->open at all. See the tty->count > 1 check.

And since we take a reference in ->install, we need also ->cleanup to
drop the reference to a view.

Final note, see that we leave raw3270_find_view in place. It is
because views are removed even from module_exit.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NJiri Slaby <jslaby@suse.cz>
Cc: Samuel Ortiz <samuel@sortiz.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

The "tty->port = port" assignment is not needed anymore since it
happens in tty_port_install implicitly.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NJiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

raw3215[line] is set in probe, but not unset in remove. This will lead
to random crashes if the device is removed and the corresponding tty
opened later. open would dereference freed memory.

So set raw3215[line] to NULL in remove to fix that.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Every tty driver needs tty_port for each line. So let us add one to
nfcon too. And link it so that the tty layer knows about it.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows us to provide the tty layer with information about
tty_port for each link.

We also provide a tty_port for the service port. For this one we allow
only ioctl, so this is pretty ugly.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* use <tab> for indentation
* add KERN_* to printks
* no more assignments in if's like if ((rc = function()))
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows us to provide the tty layer with information about
tty_port for each link. And it also allows us to get rid of the
remove_device loop in synclink_cs_exit because we had to reorder
pcmcia and tty driver registration in init. This was because we need
to have serial_driver initialized when calling
tty_port_register_device from pcmcia ->probe.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We will need to change the order of tty and pcmcia drivers
initializations (see the reason later in this series). And the fail
path handling is currently performed in a separate function that as
well takes care of proper deinitialization in module_exit. It is hard
to read and will need to be adjusted by our changes anyway. Instead,
get rid of this helper function and do the fail paths handling
directly in the init function. (And move the body of the function to
module_exit.)
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

So now for those drivers that can use neither tty_port_install nor
tty_port_register_driver but still have tty_port available before
tty_register_driver we use newly added tty_port_link_device.

The rest of the drivers that still do not provide tty_struct <->
tty_port link will have to be converted to implement
tty->ops->install.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is for those drivers which do not have dynamic device creation
(do not call tty_port_register_device) and do not want to implement
tty->ops->install (will not call tty_port_install). They still have to
provide the link somehow though.

And this newly added function is exactly to serve that purpose.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I forgot to document tty_port_register_device and tty_port_install
when they were added. Fix it now.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This looks like it was a mistake not to create device nodes for these
drivers. Let us create them from now on.

It will be necessary to call tty_register_device some way, either by
tty_register_driver implicitly or to call tty_register_device proper.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: netdev@vger.kernel.org
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Cc: linux-cris-kernel@axis.com
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently we have no way to assign tty->port while performing tty
installation. There are two ways to provide the link tty_struct =>
tty_port. Either by calling tty_port_install from tty->ops->install or
tty_port_register_device called instead of tty_register_device when
the device is being set up after connected.

In this patch we modify most of the drivers to do the latter. When the
drivers use tty_register_device and we have tty_port already, we
switch to tty_port_register_device. So we have the tty_struct =>
tty_port link for free for those.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg 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: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg 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: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg 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: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switch to the new driver allocation interface, as this is one of the
special call-sites. Here, we need TTY_DRIVER_DYNAMIC_ALLOC to not
allocate tty_driver->ports, cdevs and potentially other structures
because we reserve too many lines in pty. Instead, it provides the
tty_port<->tty_struct link in tty->ops->install already.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg 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: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On module unload, in tty3270_exit, we forgot to free the tty driver.
Add there a call to put_tty_driver.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After tty_register_driver is called, it is too late to initialize a
guy with which we operate in open. When a process already called
open(2) on that node, the structures may be in use uninitialized.

Move the initialization prior to tty_register_driver.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Samo Pogacnik <samo_pogacnik@t-2.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If a user provides a buffer larger than a tty->write_buf chunk and
passes '\r' at the end of the buffer, we touch an out-of-bound memory.

Add a check there to prevent this.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: stable@vger.kernel.org (everything maintained past v2.6.37)
Cc: Samo Pogacnik <samo_pogacnik@t-2.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the tty_printk driver fails to create a node in sysfs, the system
crashes. It is because the driver registers a tty driver and frees it
without deregistering it first. The fix is easy: add a call to
tty_unregister_driver to the fail path.

This is very unlikely to happen in usual environment => no need for
stable.

The crash occurs at some place where we iterate over tty drivers
first. It may look like this:
BUG: unable to handle kernel paging request at ffffffffffffff84
IP: [<ffffffff81278d56>] tty_open+0xd6/0x650
PGD 1a0d067 PUD 1a0e067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU 0
Pid: 1183, comm: boot.localnet Tainted: G        W    3.5.0-rc7-next-20120716+ #369 Bochs Bochs
RIP: 0010:[<ffffffff81278d56>]  [<ffffffff81278d56>] tty_open+0xd6/0x650
RSP: 0018:ffff8800162b3b98  EFLAGS: 00010207
RAX: 0000000000000000 RBX: ffff880016ba6200 RCX: 0000000000002208
RDX: 0000000000000000 RSI: 00000000000000d0 RDI: ffffffff81a35080
RBP: ffff8800162b3c08 R08: ffffffff81276f42 R09: 0000000000400040
R10: ffff8800161dc005 R11: ffff8800188ee048 R12: 0000000000000000
R13: ffffffffffffff58 R14: 0000000000400040 R15: 0000000000008000
FS:  00007f3684abd700(0000) GS:ffff880018e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffff84 CR3: 000000001503e000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process boot.localnet (pid: 1183, threadinfo ffff8800162b2000, task ffff8800188c5880)
Stack:
 ffff8800162b3c08 ffffffff81363d63 ffffffff81a62940 ffff8800189b4e88
 ffff8800188c5880 ffffffff81123180 0000000000000000 ffffffff18b20600
 0000000000000000 ffff8800189b4e88 ffff880016ba6200 ffff880018b20600
Call Trace:
 [<ffffffff81363d63>] ? kobj_lookup+0x103/0x160
 [<ffffffff81123180>] ? mount_fs+0x110/0x110
 [<ffffffff81123a9c>] chrdev_open+0x9c/0x1a0
 [<ffffffff81123a00>] ? cdev_put+0x30/0x30
 [<ffffffff8111de76>] do_dentry_open.isra.19+0x1e6/0x270
 [<ffffffff8111df65>] finish_open+0x65/0xa0
 [<ffffffff8112dc9e>] do_last.isra.52+0x26e/0xd80
 [<ffffffff8112b163>] ? inode_permission+0x13/0x50
 [<ffffffff8112b203>] ? link_path_walk+0x63/0x940
 [<ffffffff8112e85b>] path_openat+0xab/0x3d0
 [<ffffffff8112ef5d>] do_filp_open+0x3d/0xa0
 [<ffffffff8113ba72>] ? alloc_fd+0xd2/0x120
 [<ffffffff8111eee3>] do_sys_open+0xf3/0x1d0
 [<ffffffff8111efdc>] sys_open+0x1c/0x20
 [<ffffffff815b5fe2>] system_call_fastpath+0x16/0x1b
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Samo Pogacnik <samo_pogacnik@t-2.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For many cards, this saves some IO space because interrupt status port
has precedence over the rest of ports on the card. Hence it can be
mapped to a hole in I/O ports.

Here we add a kernel parameter which allows that if a user wants to.
But they need to explicitly enable it by a module parameter.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>