We really don't want to mark the pty as a low-latency device, because as
Alan points out, the ->write method can be called from an IRQ (ppp?),
and that means we can't use ->low_latency=1 as we take mutexes in the
low_latency case.
So rather than using low_latency to force the written data to be pushed
to the ldisc handling at 'write()' time, just make the reader side (or
the poll function) do the flush when it checks whether there is data to
be had.
This also fixes the problem with lost data in an emacs compile buffer
(bugzilla 13815), and we can thus revert the low_latency pty hack
(commit 3a54297478: "pty: quickfix for the
pty ENXIO timing problems").
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ Modified to do the tty_flush_to_ldisc() inside input_available_p() so
that it triggers for both read and poll() - Linus]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This also makes close stall in the normal case which is apparently
needed to fix emacs
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function does not have an error return and returning an error is
instead interpreted as having a lot of pending bytes.
Reported by Jeff Harris who provided a list of some of the remaining
offenders.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If spin_lock_irqsave is called twice in a row with the same second
argument, the interrupt state at the point of the second call overwrites
the value saved by the first call. Indeed, the second call does not
need to save the interrupt state, so it is changed to a simple
spin_lock.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
expression lock1,lock2;
expression flags;
@@
*spin_lock_irqsave(lock1,flags)
... when != flags
*spin_lock_irqsave(lock2,flags)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The buffer for the consoles are unconditionally allocated at con_init()
time, which miss the creation of the vcs(a) devices.
Since 2.6.30 (commit 4995f8ef9d, 'vcs:
hook sysfs devices into object lifetime instead of "binding"' to be
exact) these devices are no longer created at open() and removed on
close(), but controlled by the lifetime of the buffers.
Reported-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>
Tested-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>
Cc: stable@kernel.org
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Whoops.. fortunately not many people use this yet.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a tty in N_TTY mode with echo enabled manages to get itself into a state
where
- echo characters are pending
- FASYNC is enabled
- tty_write_wakeup is called from either
- a device write path (pty)
- an IRQ (serial)
then it either deadlocks or explodes taking a mutex in the IRQ path.
On the serial side it is almost impossible to reproduce because you have to
go from a full serial port to a near empty one with echo characters
pending. The pty case happens to have become possible to trigger using
emacs and ptys, the pty changes having created a scenario which shows up
this bug.
The code path is
n_tty:process_echoes() (takes mutex)
tty_io:tty_put_char()
pty:pty_write (or serial paths)
tty_wakeup (from pty_write or serial IRQ)
n_tty_write_wakeup()
process_echoes()
*KABOOM*
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't forget to drop a tty refererence on fail paths in
receive_data().
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bootmem is not used for the vt screen buffer anymore as slab is now
available at the time the console is initialized.
Get rid of the now superfluous distinction between slab and bootmem,
it's always slab.
This also fixes a kmalloc leak which Catalin described thusly:
Commit a5f4f52e ("vt: use kzalloc() instead of the bootmem allocator")
replaced the alloc_bootmem() with kzalloc() but didn't set vc_kmalloced to
1 and the memory block is later leaked. The corresponding kmemleak trace:
unreferenced object 0xdf828000 (size 8192):
comm "swapper", pid 0, jiffies 4294937296
backtrace:
[<c006d473>] __save_stack_trace+0x17/0x1c
[<c000d869>] log_early+0x55/0x84
[<c01cfa4b>] kmemleak_alloc+0x33/0x3c
[<c006c013>] __kmalloc+0xd7/0xe4
[<c00108c7>] con_init+0xbf/0x1b8
[<c0010149>] console_init+0x11/0x20
[<c0008797>] start_kernel+0x137/0x1e4
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can get a situation where a hangup occurs during or after a close. In
that case the ldisc gets disposed of by the close and the hangup then
explodes.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 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: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 5fd29d6ccb ("printk: clean up
handling of log-levels and newlines") changed printk semantics. printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.
<level> is now included in the output on each additional use.
Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes the ppp problems and various other issues with call locking
caused by one side of a pty called in one locking context trying to match
another with differing rules on the other side. We also get a big slack
space to work with that means we can bury the flow control deadlock case
for any conceivable real world situation.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we reinit the ldisc on final tty close which is what the old code
did to ensure that if the device retained its termios settings then it had the
right ldisc. tty_ldisc_reinit does that but also leaves us with the reset
ldisc reference which is then leaked.
At this point we know the port will be recycled so we can kill the ldisc
off completely rather than try and add another ldisc free up when the kref
count hits zero.
At this point it is safe to keep the ldisc closed as tty_ldisc waiting
methods are only used from the user side, and as the final close we are
the last such reference. Interrupt/driver side methods will always use the
non wait version and get back a NULL.
Found with kmemleak and investigated/identified by Catalin Marinas.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On Mon, Nov 17, 2008 at 01:26:13AM -0600, Sonny Rao wrote:
> On Fri, Nov 07, 2008 at 04:28:29PM +1100, Paul Mackerras wrote:
> > Sonny Rao writes:
> >
> > > Fix the BSR driver to allow small BSR devices, which are limited to a
> > > single 4k space, on a 64k page kernel. Previously the driver would
> > > reject the mmap since the size was smaller than PAGESIZE (or because
> > > the size was greater than the size of the device). Now, we check for
> > > this case use remap_4k_pfn(). Also, take out code to set vm_flags,
> > > as the remap_pfn functions will do this for us.
> >
> > Thanks.
> >
> > Do we know that the BSR size will always be 4k if it's not a multiple
> > of 64k? Is it possible that we could get 8k, 16k or 32k or BSRs?
> > If it is possible, what does the user need to be able to do? Do they
> > just want to map 4k, or might then want to map the whole thing?
>
>
> Hi Paul, I took a look at changing the driver to reject a request for
> mapping more than a single 4k page, however the only indication we get
> of the requested size in the mmap function is the vma size, and this
> is always one page at minimum. So, it's not possible to determine if
> the user wants one 4k page or more. As I noted in my first response,
> there is only one case where this is even possible and I don't think
> it is a significant concern.
>
> I did notice that I left out the check to see if the user is trying to
> map more than the device length, so I fixed that. Here's the revised
> patch.
Alright, I've reworked this now so that if we get one of these cases
where there's a bsr that's > 4k and < 64k on a 64k kernel we'll only
advertise that it is a 4k BSR to userspace. I think this is the best
solution since user programs are only supposed to look at sysfs to
determine how much can be mapped, and libbsr does this as well.
Please consider for 2.6.31 as a fix, thanks.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Add a 4096 byte BSR size which will be used on new machines. Also, remove
the warning when we run into an unknown size, as this can spam the kernel
log excessively.
Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The kernel oopses if this flag is set.
[and neither driver should set it as they call tty_flip_buffer_push from IRQ
paths so have always been buggy]
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 3e3b5c0877 ("tty: use
prepare/finish_wait"), tty_port_block_til_ready() is using
prepare_to_wait()/finish_wait(). Those functions require that the
wait_queue_t be initialised with .func=autoremove_wake_function, via
DEFINE_WAIT().
But the conversion from DECLARE_WAITQUEUE() to DEFINE_WAIT() was not made,
so this code will oops in finish_wait().
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix race condition when adding transmit data to active DMA buffer ring
that can cause transmit stall.
Update transmit timeout when adding data to active DMA buffer ring.
Base transmit timeout on amount of buffered data instead of using fixed
value.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add flush_buffer tty callback to flush rx buffers.
Add TCFLSH ioctl processing to flush tx buffers.
Increase default tx buffers from 1 to 3.
Remove unneeded flush_buffer call in open callback.
Remove vendor specific CVS version string.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't return from switch/case directly in vt_ioctl. Set ret and break
instead so that we unlock BKL.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't return from switch/case, break instead, so that we unlock BKL.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is omitted BKunL in r3964_read.
Centralize the paths to one point with one unlock.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The original patch garned some feedback and a v2 was posted, but that
version seems to have been missed when merging the driver.
At any rate, this cleans up the printk usage as suggested by Jiri Slaby.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit a90b037583, which
already got fixed as commit f0e8527726:
the same patch (trivial differences) got applied twice.
Requested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (35 commits)
Input: add driver for Synaptics I2C touchpad
Input: synaptics - add support for reporting x/y resolution
Input: ALPS - handle touchpoints buttons correctly
Input: gpio-keys - change timer to workqueue
Input: ads7846 - pin change interrupt support
Input: add support for touchscreen on W90P910 ARM platform
Input: appletouch - improve finger detection
Input: wacom - clear Intuos4 wheel data when finger leaves proximity
Input: ucb1400 - move static function from header into core
Input: add driver for EETI touchpanels
Input: ads7846 - more detailed model name in sysfs
Input: ads7846 - support swapping x and y axes
Input: ati_remote2 - use non-atomic bitops
Input: introduce lm8323 keypad driver
Input: psmouse - ESD workaround fix for OLPC XO touchpad
Input: tsc2007 - make sure platform provides get_pendown_state()
Input: uinput - flush all pending ff effects before destroying device
Input: simplify name handling for certain input handles
Input: serio - do not use deprecated dev.power.power_state
Input: wacom - add support for Intuos4 tablets
...
* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (24 commits)
agp/intel: Make intel_i965_mask_memory use dma_addr_t for physical addresses
agp: add user mapping support to ATI AGP bridge.
drm/i915: enable GEM on PAE.
drm/radeon: fix unused variables warning
agp: switch AGP to use page array instead of unsigned long array
agpgart: detected ALi M???? chipset with M1621
drm/radeon: command stream checker for r3xx-r5xx hardware
drm/radeon: Fully initialize LVDS info also when we can't get it from the ROM.
radeon: Fix CP byte order on big endian architectures with KMS.
agp/uninorth: Handle user memory types.
drm/ttm: Add some powerpc cache flush code.
radeon: Enable modesetting on non-x86.
drm/radeon: Respect AGP cant_use_aperture flag.
drm: EDID endianness fixes.
drm/radeon: this VRAM vs aperture test is wrong, just remove it.
drm/ttm: fix an error path to exit function correctly
drm: Apply "Memory fragmentation from lost alignment blocks"
ttm: Return -ERESTART when a signal interrupts bo eviction.
drm: Remove memory debugging infrastructure.
drm/i915: Clear fence register on tiling stride change.
...
Otherwise, the high bits to be stuffed in the unused lower bits of the
page address are lost.
Signed-off-by: Pierre Willenbrock <pierre@pirsoft.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
In moxa.c there are 32 minor numbers reserved for each device. The number
of ports actually available per device is stored in
moxa_board_conf->numPorts. This number is not considered in moxa_open().
Opening a port that is not available results in a kernel oops. This patch
adds a test to moxa_open() that prevents opening unavailable ports.
[akpm@linux-foundation.org: avoid multiple returns]
Signed-off-by: Dirk Eibach <eibach@gdsys.de>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The remove member of the pci_driver stli_pcidriver uses __devexit_p(), so
the remove function itself should be marked with __devexit. Even more so
considering the probe function is marked with __devinit.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With a postfix increment retries is incremented beyond DTLK_MAX_RETRIES so
the error message is not displayed correctly.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: James R. Van Zandt <jrv@vanzandt.mv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This switches AGP to use an array of pages for tracking the
pages allocated to the GART. This should enable GEM on PAE to work
a lot better as we can pass highmem pages to the PAT code and it will
do the right thing with them.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add M1621 chipset name to ali-agp, preventing "Detected ALi M???? chipset"
message.
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Currently the sysrq-c handler is bit over-engineered. Its behavior is
dependent on a few compile time and run time factors that alter its
behavior which is really unnecessecary.
If CONFIG_KEXEC is not configured, sysrq-c, crashes the system with a NULL
pointer dereference. If CONFIG_KEXEC is configured, it calls crash_kexec
directly, which implies that the kexec kernel will either be booted (if
its been previously loaded), or it will simply do nothing (the no kexec
kernel has been loaded).
It would be much easier to just simplify the whole thing to dereference a
NULL pointer all the time regardless of configuration. That way, it will
always try to crash the system, and if a kexec kernel has been loaded into
reserved space, it will still boot from the page fault trap handler
(assuming panic_on_oops is set appropriately).
[akpm@linux-foundation.org: build fix]
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Brayan Arraes <brayan@yack.com.br>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
One of my programs frequently grabs the parport, does something with it
and then drops it again. This results in spamming of the kernel log with
"... registered pardevice"
"... unregistered pardevice"
These messages are completely useless, except for debugging ppdev,
probably. So put them under DEBUG (or dynamic debug).
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix this:
isicom.c: In function `isicom_probe':
isicom.c:1587: warning: `signature' may be used uninitialized in this function
by uninitialized_var(), because if the signature is not initialized in
reset_card(), we won't use it.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory_open() ignores devlist and does a switch for each item, duplicating
code and conditional definitions.
Clean it up by adding backing_dev_info to devlist and use it to lookup for
the minor device.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Adriano dos Santos Fernandes <adrianosf@uol.com.br>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Blackfin platforms do not support the hardware which this driver drives.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] Convert ia64 to use int-ll64.h
[IA64] Fix build error in paravirt_patchlist.c
[IA64] ia64 does not need umount2() syscall
[IA64] hook up new rt_tgsigqueueinfo syscall
[IA64] msi_ia64.c dmar_msi_type should be static
[IA64] remove obsolete hw_interrupt_type
[IA64] remove obsolete irq_desc_t typedef
[IA64] remove obsolete no_irq_type
[IA64] unexport fpswa.h
It is generally agreed that it would be beneficial for u64 to be an
unsigned long long on all architectures. ia64 (in common with several
other 64-bit architectures) currently uses unsigned long. Migrating
piecemeal is too painful; this giant patch fixes all compilation warnings
and errors that come as a result of switching to use int-ll64.h.
Note that userspace will still see __u64 defined as unsigned long. This
is important as it affects C++ name mangling.
[Updated by Tony Luck to change efi.h:efi_freemem_callback_t to use
u64 for start/end rather than unsigned long]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch adds support for the integrated RNG of the TX4939 SoC.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* akpm: (182 commits)
fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset
fbdev: *bfin*: fix __dev{init,exit} markings
fbdev: *bfin*: drop unnecessary calls to memset
fbdev: bfin-t350mcqb-fb: drop unused local variables
fbdev: blackfin has __raw I/O accessors, so use them in fb.h
fbdev: s1d13xxxfb: add accelerated bitblt functions
tcx: use standard fields for framebuffer physical address and length
fbdev: add support for handoff from firmware to hw framebuffers
intelfb: fix a bug when changing video timing
fbdev: use framebuffer_release() for freeing fb_info structures
radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb?
s3c-fb: CPUFREQ frequency scaling support
s3c-fb: fix resource releasing on error during probing
carminefb: fix possible access beyond end of carmine_modedb[]
acornfb: remove fb_mmap function
mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF
mb862xxfb: restrict compliation of platform driver to PPC
Samsung SoC Framebuffer driver: add Alpha Channel support
atmel-lcdc: fix pixclock upper bound detection
offb: use framebuffer_alloc() to allocate fb_info struct
...
Manually fix up conflicts due to kmemcheck in mm/slab.c
The console blank timer is currently hardcoded to 10*60 seconds which
might be annoying on systems with no input devices attached to wake up the
console again. Especially during development, disabling the screen saver
can be handy - for example when debugging the root fs mount mechanism or
other scenarios where no userspace program could be started to do that at
runtime from userspace.
This patch defines a core_param for the variable in charge which allows
users to entirely disable the blank feature at boot time by setting it 0.
The value can still be overwritten at runtime using the standard ioctl
call - this just allows to conditionally change the default.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
