The ocfs2_extent_tree_operations structure gains a field prefix on its
members.  The ->eo_sanity_check() operation gains a wrapper function for
completeness.  All of the extent tree operation wrappers gain a
consistent name (ocfs2_et_*()).
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

This patch fixes the following build warnings:

fs/ocfs2/xattr.c: In function 'ocfs2_half_xattr_bucket':
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 7 has type 'long int'
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 8 has type 'long int'
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 7 has type 'long int'
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 8 has type 'long int'
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 7 has type 'long int'
fs/ocfs2/xattr.c:3282: warning: format '%d' expects type 'int', but argument 8 has type 'long int'
fs/ocfs2/xattr.c: In function 'ocfs2_xattr_set_entry_in_bucket':
fs/ocfs2/xattr.c:4092: warning: format '%d' expects type 'int', but argument 6 has type 'size_t'
fs/ocfs2/xattr.c:4092: warning: format '%d' expects type 'int', but argument 6 has type 'size_t'
fs/ocfs2/xattr.c:4092: warning: format '%d' expects type 'int', but argument 6 has type 'size_t'
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

This patch adds the s_incompat flag for extended attribute support. This
helps us ensure that older versions of Ocfs2 or ocfs2-tools will not be able
to mount a volume with xattr support.
Signed-off-by: Tiger Yang <tiger.yang@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

In inode removal, we need to iterate all the buckets, remove any
externally-stored EA values and delete the xattr buckets.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Where the previous patches added the ability of list/get xattr in buckets
for ocfs2, this patch enables ocfs2 to store large numbers of EAs.

The original design doc is written by Mark Fasheh, and it can be found in
http://oss.oracle.com/osswiki/OCFS2/DesignDocs/IndexedEATrees. I only had to
make small modifications to it.

First, because the bucket size is 4K, a new field named xh_free_start is added
in ocfs2_xattr_header to indicate the next valid name/value offset in a bucket.
It is used when we store new EA name/value. With this field, we can find the
place more quickly and what's more, we don't need to sort the name/value every
time to let the last entry indicate the next unused space. This makes the
insert operation more efficient for blocksizes smaller than 4k.

Because of the new xh_free_start, another field named as xh_name_value_len is
also added in ocfs2_xattr_header. It records the total length of all the
name/values in the bucket. We need this so that we can check it and defragment
the bucket if there is not enough contiguous free space.

An xattr insertion looks like this:
1. xattr_index_block_find: find the right bucket by the name_hash, say bucketA.
2. check whether there is enough space in bucketA. If yes, insert it directly
   and modify xh_free_start and xh_name_value_len accordingly. If not, check
   xh_name_value_len to see whether we can store this by defragment the bucket.
   If yes, defragment it and go on insertion.
3. If defragement doesn't work, check whether there is new empty bucket in
   the clusters within this extent record. If yes, init the new bucket and move
   all the buckets after bucketA one by one to the next bucket. Move half of the
   entries in bucketA to the next bucket and go on insertion.
4. If there is no new bucket, grow the extent tree.

As for xattr deletion, we will delete an xattr bucket when all it's xattrs
are removed and move all the buckets after it to the previous one. When all
the xattr buckets in an extend record are freed, free this extend records
from ocfs2_xattr_tree.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

In xattr bucket, we want to limit the maximum size of a btree leaf,
otherwise we'll lose the benefits of hashing because we'll have to search
large leaves.

So add a new field in ocfs2_extent_tree which indicates the maximum leaf cluster
size we want so that we can prevent ocfs2_insert_extent() from merging the leaf
record even if it is contiguous with an adjacent record.

Other btree types are not affected by this change.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Add code to lookup a given extended attribute in the xattr btree. Lookup
follows this general scheme:

1. Use ocfs2_xattr_get_rec to find the xattr extent record

2. Find the xattr bucket within the extent which may contain this xattr

3. Iterate the bucket to find the xattr. In ocfs2_xattr_block_get(), we need
   to recalcuate the block offset and name offset for the right position of
   name/value.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Ocfs2 breaks up xattr index tree leaves into 4k regions, called buckets.
Attributes are stored within a given bucket, depending on hash value.

After a discussion with Mark, we decided that the per-bucket index
(xe_entry[]) would only exist in the 1st block of a bucket. Likewise,
name/value pairs will not straddle more than one block. This allows the
majority of operations to work directly on the buffer heads in a leaf block.

This patch adds code to iterate the buckets in an EA. A new abstration of
ocfs2_xattr_bucket is added. It records the bhs in this bucket and
ocfs2_xattr_header. This keeps the code neat, improving readibility.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

When necessary, an ocfs2_xattr_block will embed an ocfs2_extent_list to
store large numbers of EAs. This patch adds a new type in
ocfs2_extent_tree_type and adds the implementation so that we can re-use the
b-tree code to handle the storage of many EAs.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

This patch implements storing extended attributes both in inode or a single
external block. We only store EA's in-inode when blocksize > 512 or that
inode block has free space for it. When an EA's value is larger than 80
bytes, we will store the value via b-tree outside inode or block.
Signed-off-by: Tiger Yang <tiger.yang@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Add the structures and helper functions we want for handling inline extended
attributes. We also update the inline-data handlers so that they properly
function in the event that we have both inline data and inline attributes
sharing an inode block.
Signed-off-by: Tiger Yang <tiger.yang@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Add some thin wrappers around ocfs2_insert_extent() for each of the 3
different btree types, ocfs2_inode_insert_extent(),
ocfs2_xattr_value_insert_extent() and ocfs2_xattr_tree_insert_extent(). The
last is for the xattr index btree, which will be used in a followup patch.

All the old callers in file.c etc will call ocfs2_dinode_insert_extent(),
while the other two handle the xattr issue. And the init of extent tree are
handled by these functions.

When storing xattr value which is too large, we will allocate some clusters
for it and here ocfs2_extent_list and ocfs2_extent_rec will also be used. In
order to re-use the b-tree operation code, a new parameter named "private"
is added into ocfs2_extent_tree and it is used to indicate the root of
ocfs2_exent_list. The reason is that we can't deduce the root from the
buffer_head now. It may be in an inode, an ocfs2_xattr_block or even worse,
in any place in an ocfs2_xattr_bucket.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

The old uptodate only handles the issue of removing one buffer_head from
ocfs2 inode's buffer cache. With xattr clusters, we may need to remove
multiple buffer_head's at a time.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Ocfs2 uses a very flexible structure for storing extended attributes on
disk. Small amount of attributes are stored directly in the inode block - up
to 256 bytes worth. If that fills up, attributes are also stored in an
external block, linked to from the inode block. That block can in turn
expand to a btree, capable of storing large numbers of attributes.

Individual attribute values are stored inline if they're small enough
(currently about 80 bytes, this can be changed though), and otherwise are
expanded to a btree. The theoretical limit to the size of an individual
attribute is about the same as an inode, though the kernel's upper bound on
the size of an attributes data is far smaller.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Factor out the non-inode specifics of ocfs2_do_extend_allocation() into a more generic
function, ocfs2_do_cluster_allocation(). ocfs2_do_extend_allocation calls
ocfs2_do_cluster_allocation() now, but the latter can be used for other
btree types as well.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

In the old extent tree operation, we take the hypothesis that we
are using the ocfs2_extent_list in ocfs2_dinode as the tree root.
As xattr will also use ocfs2_extent_list to store large value
for a xattr entry, we refactor the tree operation so that xattr
can use it directly.

The refactoring includes 4 steps:
1. Abstract set/get of last_eb_blk and update_clusters since they may
   be stored in different location for dinode and xattr.
2. Add a new structure named ocfs2_extent_tree to indicate the
   extent tree the operation will work on.
3. Remove all the use of fe_bh and di, use root_bh and root_el in
   extent tree instead. So now all the fe_bh is replaced with
   et->root_bh, el with root_el accordingly.
4. Make ocfs2_lock_allocators generic. Now it is limited to be only used
   in file extend allocation. But the whole function is useful when we want
   to store large EAs.

Note: This patch doesn't touch ocfs2_commit_truncate() since it is not used
for anything other than truncate inode data btrees.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

ocfs2_extend_meta_needed(), ocfs2_calc_extend_credits() and
ocfs2_reserve_new_metadata() are all useful for extent tree operations. But
they are all limited to an inode btree because they use a struct
ocfs2_dinode parameter. Change their parameter to struct ocfs2_extent_list
(the part of an ocfs2_dinode they actually use) so that the xattr btree code
can use these functions.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

ocfs2_num_free_extents() is used to find the number of free extent records
in an inode btree. Hence, it takes an "ocfs2_dinode" parameter. We want to
use this for extended attribute trees in the future, so genericize the
interface the take a buffer head. A future patch will allow that buffer_head
to contain any structure rooting an ocfs2 btree.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

A per-mount debugfs file, "local_alloc" is created which when read will
expose live state of the nodes local alloc file. Performance impact is
minimal, only a bit of memory overhead per mount point. Still, the code is
hidden behind CONFIG_OCFS2_FS_STATS. This feature will help us debug
local alloc performance problems on a live system.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Ocfs2's local allocator disables itself for the duration of a mount point
when it has trouble allocating a large enough area from the primary bitmap.
That can cause performance problems, especially for disks which were only
temporarily full or fragmented. This patch allows for the allocator to
shrink it's window first, before being disabled. Later, it can also be
re-enabled so that any performance drop is minimized.

To do this, we allow the value of osb->local_alloc_bits to be shrunk when
needed. The default value is recorded in a mostly read-only variable so that
we can re-initialize when required.

Locking had to be updated so that we could protect changes to
local_alloc_bits. Mostly this involves protecting various local alloc values
with the osb spinlock. A new state is also added, OCFS2_LA_THROTTLED, which
is used when the local allocator is has shrunk, but is not disabled. If the
available space dips below 1 megabyte, the local alloc file is disabled. In
either case, local alloc is re-enabled 30 seconds after the event, or when
an appropriate amount of bits is seen in the primary bitmap.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

Do this instead of tracking absolute local alloc size. This avoids
needless re-calculatiion of bits from bytes in localalloc.c. Additionally,
the value is now in a more natural unit for internal file system bitmap
work.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.

Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/blackfin-2.6: (60 commits)
  Blackfin arch: make sure we include the fix for SPORT hysteresis when reprogramming clocks
  Blackfin arch: Fix bogus str_ident check in gpio code
  Blackfin arch: AD7879 Touchscreen driver
  Blackfin arch: introducing bfin_addr_dcachable
  Blackfin arch: fix a typo in comments
  Blackfin arch: Remove useless head file
  Blackfin arch: make sure L2 start and length are always defined (fixes building on BF542)
  Blackfin arch: use the Blackfin on-chip ROM to do software reset when possible
  Blackfin arch: update anomaly headers to match the latest sheet
  Blackfin arch: bfin_reset() is an internal reboot function ... everyone should go through machine_restart()
  Blackfin arch: print out error/warning if you are running on the incorrect CPU type
  Blackfin arch: remove non-bf54x ifdef logic since this file is only compiled on bf54x parts
  Blackfin arch: update board defconfigs
  Blackfin arch: Add optional verbose debug
  Blackfin arch: emulate a TTY over the EMUDAT/JTAG interface
  Blackfin arch: have is_user_addr_valid() check for overflows (like when address is -1)
  Blackfin arch: ptrace - fix off-by-one check on end of memory regions
  Blackfin arch: Enable framebuffer support for the BF526-EZkit TFT LCD display
  Blackfin arch: flash memory map and dm9000 resources updating
  Blackfin arch: early prink code still use uart core console functions to parse and set configure option string
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  net/mac80211/rx.c: fix build error
  acpi: Make ACPI_TOSHIBA depend on INPUT.
  net/bfin_mac.c MDIO namespace fixes
  jme: remove unused #include <version.h>
  netfilter: remove unused #include <version.h>
  net: Fix off-by-one in skb_dma_map
  smc911x: Add support for LAN921{5,7,8} chips from SMSC
  qlge: remove duplicated #include
  wireless: remove duplicated #include
  net/au1000_eth.c MDIO namespace fixes
  net/tc35815.c: fix compilation
  sky2: Fix WOL regression
  r8169: NULL pointer dereference on r8169 load

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  chmc: Mark %ver register inline asm with __volatile__
  sparc64: Add missing notify_cpu_starting() call.
  sparc32: fix build errors

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: (33 commits)
  ALSA: ASoC codec: remove unused #include <version.h>
  ALSA: ASoC: update email address for Liam Girdwood
  ALSA: hda: corrected invalid mixer values
  ALSA: hda: add mixers for analog mixer on 92hd75xx codecs
  ALSA: ASoC: Add destination and source port for DMA on OMAP1
  ALSA: ASoC: Drop device registration from GTA01 lm4857 driver
  ALSA: ASoC: Fix build of GTA01 audio driver
  ALSA: ASoC: Add widgets before setting endpoints on GTA01
  ALSA: ASoC: Fix inverted input PGA mute bits in WM8903
  ALSA: ASoC: OMAP: Set DMA stream name at runtime in McBSP DAI driver
  ALSA: ASoC: OMAP: Add support for OMAP2430 and OMAP34xx in McBSP DAI driver
  ALSA: ASoC: OMAP: Add multilink support to McBSP DAI driver
  ALSA: ASoC: Make TLV320AIC26 user-visible
  ALSA: ASoC - clean up Kconfig for TLV320AIC2
  ALSA: ASoC: Make WM8510 microphone input a DAPM mixer
  ALSA: ASoC: Implement WM8510 bias level control
  ALSA: ASoC: Remove unused AUDIO_NAME define from codec drivers
  ALSA: ASoC: tlv320aic3x: Use uniform tlv320aic naming
  ALSA: ASoC: Add WM8510 SPI support
  ALSA: ASoC: Add WM8753 SPI support
  ...

* 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc:
  proc: remove kernel.maps_protect
  proc: remove now unneeded ADDBUF macro
  [PATCH] proc: show personality via /proc/pid/personality
  [PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock()
  proc: move PROC_PAGE_MONITOR to fs/proc/Kconfig
  proc: make grab_header() static
  proc: remove unused get_dma_list()
  proc: remove dummy vmcore_open()
  proc: proc_sys_root tweak
  proc: fix return value of proc_reg_open() in "too late" case

Fixed up trivial conflict in removed file arch/sparc/include/asm/dma_32.h

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (24 commits)
  integrity: special fs magic
  As pointed out by Jonathan Corbet, the timer must be deleted before
  ERROR: code indent should use tabs where possible
  The tpm_dev_release function is only called for platform devices, not pnp
  Protect tpm_chip_list when transversing it.
  Renames num_open to is_open, as only one process can open the file at a time.
  Remove the BKL calls from the TPM driver, which were added in the overall
  netlabel: Add configuration support for local labeling
  cipso: Add support for native local labeling and fixup mapping names
  netlabel: Changes to the NetLabel security attributes to allow LSMs to pass full contexts
  selinux: Cache NetLabel secattrs in the socket's security struct
  selinux: Set socket NetLabel based on connection endpoint
  netlabel: Add functionality to set the security attributes of a packet
  netlabel: Add network address selectors to the NetLabel/LSM domain mapping
  netlabel: Add a generic way to create ordered linked lists of network addrs
  netlabel: Replace protocol/NetLabel linking with refrerence counts
  smack: Fix missing calls to netlbl_skbuff_err()
  selinux: Fix missing calls to netlbl_skbuff_err()
  selinux: Fix a problem in security_netlbl_sid_to_secattr()
  selinux: Better local/forward check in selinux_ip_postroute()
  ...

* git://git.infradead.org/users/dwmw2/random-2.6:
  Fix autoloading of MacBook Pro backlight driver.
  Automatic MODULE_ALIAS() for DMI match tables.
  Remove asm/a.out.h files for all architectures without a.out support.
  Introduce HAVE_AOUT symbol to remove hard-coded arch list for BINFMT_AOUT
  Remove redundant CONFIG_ARCH_SUPPORTS_AOUT
  S390: Update comments about why we don't use <asm-generic/statfs.h>
  SPARC: Use <asm-generic/statfs.h>
  PowerPC: Use <asm-generic/statfs.h>
  PARISC: Use <asm-generic/statfs.h>
  x86_64: Use <asm-generic/statfs.h>
  IA64: Use <asm-generic/statfs.h>
  ARM: Use <asm-generic/statfs.h>
  Make <asm-generic/statfs.h> suitable for 64-bit platforms.
  Define and use PCI_DEVICE_ID_MARVELL_88ALP01_CCIC for CAFÉ camera driver
  [MTD] [NAND] Define and use PCI_DEVICE_ID_MARVELL_88ALP01_NAND for CAFÉ
  Use PCI_DEVICE_ID_88ALP01 for CAFÉ chip, rather than PCI_DEVICE_ID_CAFE.
  EFS: Don't set f_fsid in statfs().

Merges oprofile, timers/hpet, x86/traps, x86/time, and x86/core misc items.

* 'x86-core-v4-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (132 commits)
  x86: change early_ioremap to use slots instead of nesting
  x86: adjust dependencies for CONFIG_X86_CMOV
  dumpstack: x86: various small unification steps, fix
  x86: remove additional_cpus
  x86: remove additional_cpus configurability
  x86: improve UP kernel when CPU-hotplug and SMP is enabled
  dumpstack: x86: various small unification steps
  dumpstack: i386: make kstack= an early boot-param and add oops=panic
  dumpstack: x86: use log_lvl and unify trace formatting
  dumptrace: x86: consistently include loglevel, print stack switch
  dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stack
  dumpstack: x86: make printk_address equal
  dumpstack: x86: move die_nmi to dumpstack_32.c
  traps: x86: finalize unification of traps.c
  traps: x86: make traps_32.c and traps_64.c equal
  traps: x86: various noop-changes preparing for unification of traps_xx.c
  traps: x86_64: use task_pid_nr(tsk) instead of tsk->pid in do_general_protection
  traps: i386: expand clear_mem_error and remove from mach_traps.h
  traps: x86_64: make io_check_error equal to the one on i386
  traps: i386: use preempt_conditional_sti/cli in do_int3
  ...

Original idea for this from a patch by Rodolfo Giometti which merges various
bits of PPS support
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Drop the kernel lock further and also correct cases where we set rc to an
error code, and then return 0
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

get_current_tty now does internal locking and returns a referenced object,
thus our use of tty_mutex here can go away.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_io.c:1413:17: warning: symbol 'buf' shadows an earlier one
drivers/char/tty_io.c:1379:20: originally declared here
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The multiple drivers share the minor space occupied by a particular major
number, the actual index within the device name's space is indicated by
the tty_driver->name_base + uart_port->line

Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line

Use those to print the device names properly in such situations in
serial_core.c and 8250.c
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Closes bug #11408 by checking the card index range for command 0
Fixes the ioctl to return ENOTTY which is correct for unknown ioctls
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove/fix some bogus NULL checks, comment some locking etc
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Many tty drivers contain 'can't happen' checks against NULL pointers passed
in by the tty layer. These have never been possible to occur. Even more
importantly if they ever do occur we want to know as it would be a serious
bug.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Stephen's fixes reminded me that gigaset is still rather broken so fix it up
a bit
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>