There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.

This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
  later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking

There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.

This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded

and probably a few other of the mysterious ldisc race reports.

I'm sure it also adds the odd new one.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Before trying to tackle the ldisc bugs the code needs to be a good deal
more readable, so do the simple extractions of routines first.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Costantino Leandro found a bug in tty_find_polling_driver and provided a
patch that fixed the crash but not the underlying bug. This fixes the
underlying bug where the list walk corrupts the values it is using on a
match but then reuses them if the open fails.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We fixed the globals, so now fix the comment
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The tty throttling code can race due to the lock drops. It takes very high
loads but this has been observed and verified by Rob Duncan.

The basic problem is that on an SMP box we can go

	CPU #1				CPU #2
	need to throttle ?
	suppose we should		buffer space cleared
					are we throttled
					yes ? - unthrottle
	call throttle method

This changeet take the termios lock to protect against this. The termios
lock isn't the initial obvious candidate but many implementations of throttle
methods already need to poke around their own termios structures (and nobody
really locks them against a racing change of flow control).

This does mean that anyone who is setting tty->low_latency = 1 and then
calling tty_flip_buffer_push from their unthrottle method is going to end up
collapsing in a pile of locks. However we've removed all the known bogus
users of low_latency = 1 and such use isn't safe anyway for other reasons so
catching it would be an improvement.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The legacy TCSETA{,W,F} ioctls failed to set the termio->c_line field
on x86. This adds a missing get_user.

The same ioctls also fail to report faulting user pointers, which
we keep ignoring.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds support for the following serial controller chip:
Oxford Semiconductor OXCB950 for PCI Cardbus interface
http://www.transdimension.com/products/serial/OXCB950.html

on this card:
ExSys EX-1370 1 port high-speed serial card for ExpressCard/34 slot
Signed-off-by: NAndre Przywara <andre.przywara@amd.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Switch from ASYNC_* to ASYNCB_*, because test_bit expects
bit number, not mask.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Switch from ASYNC_* to ASYNCB_*, because {test,set}_bit expect
bit number, not mask.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Define ASYNCB_* flags which are bit numbers of the ASYNC_* flags.
This is useful for {test,set,clear}_bit.

Also convert each ASYNC_% to be (1 << ASYNCB_%) and define masks
with the macros, not constants.

Tested with:
#include "PATH_TO_KERNEL/include/linux/serial.h"
static struct {
        unsigned int new, old;
} as[] = {
        { ASYNC_HUP_NOTIFY, 0x0001 },
        { ASYNC_FOURPORT, 0x0002 },
...
	{ ASYNC_BOOT_ONLYMCA, 0x00400000 },
        { ASYNC_INTERNAL_FLAGS, 0xFFC00000 }
};
...
        for (a = 0; a < ARRAY_SIZE(as); a++)
                if (as[a].old != as[a].new)
                        printf("%.8x != %.8x\n", as[a].old, as[a].new);
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Or at least most of it. There are further clean ups possible and there are
are also thing checkpatch moans about that would be silly to "fix".

Also note some FIXME points found as the cleanup was done.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now we have a port structure begin using the fields and kref counts
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Set up ports right after FW load so that we won't allocate maximal
(64) ports when we use few.

Also remove reading of nports in irq context, since we know it from
initialisation now.

This also fixes a tty ports unregistration on some fail paths and for
Ze which registered 64 and unregistered real port count.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

They are unused anyway.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove ugly macros and add inlines instead of them. This improves
readability and type checking a much.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Store HW version locally to not read it all the time in interrupts
and alike.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove ugly all-over-the-code casts of ctl_addr to 9060 space.
Add an union to the cyclades_card structure, which contains
a pointer to both 9050 and 9060 spaces.

The 9050 space layout is unknown, so let it still as a void
__iomem pointer.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add receive programmed IO mode to reduce receive latency
when using low data rates. The receive FIFO trigger
level of 128 bytes used in DMA mode creates excessive latency
when operating at low data rates. PIO mode is selected when user
application requests data in blocks of less than 128 bytes.
Signed-off-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The CDC ACM driver uses the tty layer correctly so needs conversion. Start by
adding and initializing the port structures.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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>

We need this for devices that cannot flush and wait, but which do not order
data and modem events. Without it we will hang up before all the data
clears the hardware. Needed for the USB changes.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some drivers implement this internally, others miss it out. Push the
behaviour into the core code as that way everyone will do it consistently.

Update the dtr rts method to raise or lower depending upon flags. Having a
single method in this style fits most of the implementations more cleanly than
two funtions.

We need this in place before we tackle the USB side
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

No need to check if dev_id is NULL, it never is.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Don't reset the PLX chip after FW load, which effectively kills
the FW, so that user had to boot manually.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Ze needs firmware to be loaded as well as Zo. Move cyz_load_fw one
level upper to achieve that.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's a bug in the mxser kernel module that still appears in the
2.6.29.4 kernel.

mxser_get_ISA_conf takes a ioaddress as its first argument, by passing the
not of the ioaddr, you're effectively passing 0 which means it won't be
able to talk to an ISA card.  I have tested this, and removing the !
fixes the problem.

Cc: "Peter Botha" <peterb@goldcircle.co.za>
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Acked-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit code, we scan buffers attached to a transaction.  During this
scan, we sometimes have to drop j_list_lock and then we recheck whether
the journal buffer head didn't get freed by journal_try_to_free_buffers().
 But checking for buffer_jbd(bh) isn't enough because a new journal head
could get attached to our buffer head.  So add a check whether the journal
head remained the same and whether it's still at the same transaction and
list.

This is a nasty bug and can cause problems like memory corruption (use after
free) or trigger various assertions in JBD code (observed).
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The recent ->lookup() deadlock correction required the directory inode
mutex to be dropped while waiting for expire completion.  We were
concerned about side effects from this change and one has been identified.

I saw several error messages.

They cause autofs to become quite confused and don't really point to the
actual problem.

Things like:

handle_packet_missing_direct:1376: can't find map entry for (43,1827932)

which is usually totally fatal (although in this case it wouldn't be
except that I treat is as such because it normally is).

do_mount_direct: direct trigger not valid or already mounted
/test/nested/g3c/s1/ss1

which is recoverable, however if this problem is at play it can cause
autofs to become quite confused as to the dependencies in the mount tree
because mount triggers end up mounted multiple times.  It's hard to
accurately check for this over mounting case and automount shouldn't need
to if the kernel module is doing its job.

There was one other message, similar in consequence of this last one but I
can't locate a log example just now.

When checking if a mount has already completed prior to adding a new mount
request to the wait queue we check if the dentry is hashed and, if so, if
it is a mount point.  But, if a mount successfully completed while we
slept on the wait queue mutex the dentry must exist for the mount to have
completed so the test is not really needed.

Mounts can also be done on top of a global root dentry, so for the above
case, where a mount request completes and the wait queue entry has already
been removed, the hashed test returning false can cause an incorrect
callback to the daemon.  Also, d_mountpoint() is not sufficient to check
if a mount has completed for the multi-mount case when we don't have a
real mount at the base of the tree.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The massive nommu update (8feae131) resulted in these warnings:
ipc/shm.c: In function `sys_shmdt':
ipc/shm.c:974: warning: unused variable `size'
ipc/shm.c:972: warning: unused variable `next'
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  kvm: fix kvm reboot crash when MAXSMP is used
  cpumask: alloc zeroed cpumask for static cpumask_var_ts
  cpumask: introduce zalloc_cpumask_var

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  bsg: setting rq->bio to NULL

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  cls_cgroup: Fix oops when user send improperly 'tc filter add' request
  r8169: fix crash when large packets are received

* 'for-linus' of git://neil.brown.name/md:
  md/raid5: fix bug in reshape code when chunk_size decreases.
  md/raid5 - avoid deadlocks in get_active_stripe during reshape
  md/raid5: use conf->raid_disks in preference to mddev->raid_disk

Due to commit 1cd96c24 ("block: WARN
in __blk_put_request() for potential bio leak"), BSG SMP requests get
the false warnings:

WARNING: at block/blk-core.c:1068 __blk_put_request+0x52/0xc0()

This sets rq->bio to NULL to avoid that false warnings.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

one system was found there is crash during reboot then kvm/MAXSMP
Sending all processes the KILL signal...                              done
Please stand by while rebooting the system...
[ 1721.856538] md: stopping all md devices.
[ 1722.852139] kvm: exiting hardware virtualization
[ 1722.854601] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 1722.872219] IP: [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1722.877955] PGD 0
[ 1722.880042] Oops: 0000 [#1] SMP
[ 1722.892548] last sysfs file: /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/host0/target0:2:0/0:2:0:0/vendor
[ 1722.900977] CPU 9
[ 1722.912606] Modules linked in:
[ 1722.914226] Pid: 0, comm: swapper Not tainted 2.6.30-rc7-tip-01843-g2305324-dirty #299 ...
[ 1722.932589] RIP: 0010:[<ffffffff8102c6b6>]  [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1722.942709] RSP: 0018:ffffc900010b6ed8  EFLAGS: 00010046
[ 1722.956121] RAX: 0000000000000000 RBX: ffffc9000e253140 RCX: 0000000000000009
[ 1722.972202] RDX: 000000000000b020 RSI: ffffc900010c3220 RDI: ffffffffffffd790
[ 1722.977399] RBP: ffffc900010b6f08 R08: 0000000000000000 R09: 0000000000000000
[ 1722.995149] R10: 00000000000004b8 R11: 966912b6c78fddbd R12: 0000000000000009
[ 1723.011551] R13: 000000000000b020 R14: 0000000000000009 R15: 0000000000000000
[ 1723.019898] FS:  0000000000000000(0000) GS:ffffc900010b3000(0000) knlGS:0000000000000000
[ 1723.034389] CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
[ 1723.041164] CR2: 0000000000000000 CR3: 0000000001001000 CR4: 00000000000006e0
[ 1723.056192] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1723.072546] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1723.080562] Process swapper (pid: 0, threadinfo ffff88107e464000, task ffff88047e5a2550)
[ 1723.096144] Stack:
[ 1723.099071]  0000000000000046 ffffc9000e253168 966912b6c78fddbd ffffc9000e253140
[ 1723.115471]  ffff880c7d4304d0 ffffc9000e253168 ffffc900010b6f28 ffffffff81011022
[ 1723.132428]  ffffc900010b6f48 966912b6c78fddbd ffffc900010b6f48 ffffffff8100b83b
[ 1723.141973] Call Trace:
[ 1723.142981]  <IRQ> <0> [<ffffffff81011022>] kvm_arch_hardware_disable+0x26/0x3c
[ 1723.158153]  [<ffffffff8100b83b>] hardware_disable+0x3f/0x55
[ 1723.172168]  [<ffffffff810b95f6>] generic_smp_call_function_interrupt+0x76/0x13c
[ 1723.178836]  [<ffffffff8104cbea>] smp_call_function_interrupt+0x3a/0x5e
[ 1723.194689]  [<ffffffff81035bf3>] call_function_interrupt+0x13/0x20
[ 1723.199750]  <EOI> <0> [<ffffffff814ad3b4>] ? acpi_idle_enter_c1+0xd3/0xf4
[ 1723.217508]  [<ffffffff814ad3ae>] ? acpi_idle_enter_c1+0xcd/0xf4
[ 1723.232172]  [<ffffffff814ad4bc>] ? acpi_idle_enter_bm+0xe7/0x2ce
[ 1723.235141]  [<ffffffff81a8d93f>] ? __atomic_notifier_call_chain+0x0/0xac
[ 1723.253381]  [<ffffffff818c3dff>] ? menu_select+0x58/0xd2
[ 1723.258179]  [<ffffffff818c2c9d>] ? cpuidle_idle_call+0xa4/0xf3
[ 1723.272828]  [<ffffffff81034085>] ? cpu_idle+0xb8/0x101
[ 1723.277085]  [<ffffffff81a80163>] ? start_secondary+0x1bc/0x1d7
[ 1723.293708] Code: b0 00 00 65 48 8b 04 25 28 00 00 00 48 89 45 e0 31 c0 48 8b 04 cd 30 ee 27 82 49 89 cc 49 89 d5 48 8b 04 10 48 8d b8 90 d7 ff ff <48> 8b 87 70 28 00 00 48 8d 98 90 d7 ff ff eb 16 e8 e9 fe ff ff
[ 1723.335524] RIP  [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1723.342076]  RSP <ffffc900010b6ed8>
[ 1723.352021] CR2: 0000000000000000
[ 1723.354348] ---[ end trace e2aec53dae150aa1 ]---

it turns out that we need clear cpus_hardware_enabled in that case.
Reported-and-tested-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

These are defined as static cpumask_var_t so if MAXSMP is not used,
they are cleared already.  Avoid surprises when MAXSMP is enabled.
Signed-off-by: NYinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

So can get cpumask_var with cpumask_clear
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>