A good watchdog driver is supposed to report when it was responsible
for resetting the system. Implement this for the s3c2410, at least on
exynos5250 and exynos5420 where we already have a pointer to the PMU
registers to read the information.
Note that exynos4 SoCs also provide the reset status, but providing
that is left as an exercise for future changes and is not plumbed up
in this patch series. Also note the exynos4 SoCs don't appear to need
any PMU config, which is why this patch separates the concepts of
having PMU Registers vs. needing PMU Config.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Add device tree support for exynos5250 and 5420 SoCs and use syscon regmap interface
to configure AUTOMATIC_WDT_RESET_DISABLE and MASK_WDT_RESET_REQUEST registers of PMU
to mask/unmask enable/disable of watchdog in probe and s2r scenarios.
Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The existing watchdog timeout worked OK but didn't deal with
rounding in an ideal way when dividing out all of its clocks.
Specifically if you had a timeout of 32 seconds and an input clock of
66666666, you'd end up setting a timeout of 31.9998 seconds and
reporting a timeout of 31 seconds.
Specifically DBG printouts showed:
s3c2410wdt_set_heartbeat: count=16666656, timeout=32, freq=520833
s3c2410wdt_set_heartbeat: timeout=32, divisor=255, count=16666656 (0000ff4f)
and the final timeout reported to the user was:
((count / divisor) * divisor) / freq
(0xff4f * 255) / 520833 = 31 (truncated from 31.9998)
the technically "correct" value is:
(0xff4f * 255) / (66666666.0 / 128) = 31.9998
By using "DIV_ROUND_UP" we can be a little more correct.
s3c2410wdt_set_heartbeat: count=16666688, timeout=32, freq=520834
s3c2410wdt_set_heartbeat: timeout=32, divisor=255, count=16666688 (0000ff50)
and the final timeout reported to the user:
(0xff50 * 255) / 520834 = 32
the technically "correct" value is:
(0xff50 * 255) / (66666666.0 / 128) = 32.0003
We'll use a DIV_ROUND_UP to solve this, generally erroring on the side
of reporting shorter values to the user and setting the watchdog to
slightly longer than requested:
* Round input frequency up to assume watchdog is counting faster.
* Round divisions by divisor up to give us extra time.
At the same time we can avoid a for loop by just doing the right math.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
On modern SoCs the watchdog timer is parented on a clock that doesn't
change every time we have a cpufreq change. That means we don't need
to constantly adjust the watchdog timer, so avoid registering for and
dealing with cpufreq transitions unless we've actually got
CONFIG_ARM_S3C24XX_CPUFREQ defined.
Note that this is more than just an optimization. The s3c2410
watchdog driver actually pats the watchdog on every CPU frequency
change. On modern systems these happen many times per second (even in
a system where "nothing" is happening). That effectively makes any
userspace watchdog program useless (the watchdog is constantly patted
by the kernel). If we need ARM_S3C24XX_CPUFREQ defined on a
multiplatform kernel we'll need to make sure that kernel supports
common clock and change this to user common clock framework.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.
Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.
Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.
On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!
If defining char-major-10-130 is needed then it should happen in
user-space.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
Remove unneeded error handling on the result of a call to
platform_get_resource when the value is passed to devm_ioremap_resource.
Move the call to platform_get_resource adjacent to the call to
devm_ioremap_resource to make the connection between them more clear.
A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
expression pdev,res,n,e,e1;
expression ret != 0;
identifier l;
@@
- res = platform_get_resource(pdev, IORESOURCE_MEM, n);
... when != res
- if (res == NULL) { ... \(goto l;\|return ret;\) }
... when != res
+ res = platform_get_resource(pdev, IORESOURCE_MEM, n);
e = devm_ioremap_resource(e1, res);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch removes the global variables in the driver file and
group them into a structure.
Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Instead of using legacy suspend/resume methods, using newer
dev_pm_ops structure allows better control over power management.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
dev_err()/dev_info() are more preferred than pr_err()/pr_info().
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch moves register and bitfield definitions to the driver itself,
removing remaining dependencies on plat/ and mach/ headers.
Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Use the newly introduced devm_ioremap_resource() instead of
devm_request_and_ioremap() which provides more consistent error handling.
devm_ioremap_resource() provides its own error messages; so all explicit
error messages can be removed from the failure code paths.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
this patchset add the timeout-sec property to the following drivers:
orion_wdt, pnx4008_wdt, s3c2410_wdt and at91sam9_wdt.
The at91sam9_wdt is tested on evk-pr3,
the other drivers are compile tested only.
Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Use devm_* functions to make cleanup paths more simple.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
calls as required by common clock framework.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
module_platform_driver() replaces module_init() and module_exit()
and makes the code simpler.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
While rebasing my "watchdog_dev: Let the driver update the timeout field on
set_timeout success" patch (before I noticed it was already picked up by Wim),
I noticed that the s3c2410_wdt driver may not always have a 1 second
resolution, this patch changes s3c2410wdt_set_heartbeat to update the
timeout to the actually achieved timeout.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Joe's patch(watchdog: Use pr_<fmt> and pr_<level>) missed parenthesis in s3c2410_wdt.c.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Since we changed the behaviour of the set_timeout operation in the
watchdog API, we need to change the allready converted drivers so
that they update the timeout field at the end of the set_timeout
operation.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Use the current logging styles.
Make sure all output has a prefix.
Add missing newlines.
Remove now unnecessary PFX, NAME, and miscellaneous other #defines.
Coalesce formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Probe function of s3c2410 watchdog calls request_irq before initializing
required value (wdt_count). This incurs resetting watchdog counter value
and watchdog-reboot during booting up.
This patch addresses such an issue by calling request_irq later.
Error handling in probe function and calling oder in remove function are
also revised accordingly.
Reported-by: Chanwoo Park <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Add two nowayout helpers for the Watchdog Timer Driver Kernel API.
And apply this to the already converted drivers.
Note: s3c2410_wdt lost the nowayout feature during the conversion.
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Looks like a typo creeped in, and driver prints
s3c2410-wdt s3c2410-wdt: watchdog active, reset abled, irq abled
instead of
s3c2410-wdt s3c2410-wdt: watchdog active, reset enabled, irq enabled
Also it may completely disinform about irq status, as it prints
"irq enabled" when S3C2410_WTCON_INTEN is in fact 0.
Fix it.
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Make this driver a user of the watchdog framework and remove now
centrally handled parts. Tested on a mini2440.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch adds the of_match_table to enable s3c2410-wdt driver
to be probed when watchdog device node is found in the device tree.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Request_mem_region should be used with release_mem_region, not
release_resource.
The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression x,E;
@@
*x = request_mem_region(...)
... when != release_mem_region(x)
when != x = E
* release_resource(x);
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: stable <stable@kernel.org>
When removing the watchdog platform device, we need to
disable the access to userspace first. It makes no sense
to remove the drivers clock, irq's, ... and then disable
userspace access.
the order of removal has also been changed so that it
is the reverse of probing (this way the clock is also
disabled sooner).
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
If the request for wdt_mem region fails, this patch modifies the driver
such that, it does not try to release the wdt_mem region on exit.
Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Fix MODULE_PARM_DESC() strings in several watchdog drivers.
Some are simple as add a parenthesis.
Others are problems from __stringify() being used on a
variable name instead of a macro name, so the variable name
is produced in the string instead of its build-time value.
In these cases, create a macro for the value so that the
module param description string is useful.
Only pc87413_wdt has been built (due to toolchains).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Use resource_size().
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Kevin Hilman <khilman@ti.deeprootsystems.com>
Cc: Ulrik Bech Hald <ubh@ti.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Vincent Sanders <support@simtec.co.uk>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add support for CPU frequency scaling to the S3C24XX Watchdog
driver.
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Remove the changelog from the top of the driver, which
is redundant as this information is more accurately
represented from the revision control holding the
file.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Fix comparison of a pointer to 0, instead of using
NULL for a invalid pointer.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
These patches from Adrian fix:
- ixp4xx_wdt: 20d35f3e50
CC drivers/watchdog/ixp4xx_wdt.o
ixp4xx_wdt.c:32: error: expected '=', ',', ';', 'asm' or '__attribute__'
ixp4xx_wdt.c: In function 'wdt_enable':
ixp4xx_wdt.c:41: error: 'wdt_lock' undeclared (first use in this
ixp4xx_wdt.c:41: error: (Each undeclared identifier is reported only
ixp4xx_wdt.c:41: error: for each function it appears in.)
ixp4xx_wdt.c: In function 'wdt_disable':
ixp4xx_wdt.c:52: error: 'wdt_lock' undeclared (first use in this
ixp4xx_wdt.c: In function 'ixp4xx_wdt_init':
ixp4xx_wdt.c:186: error: 'wdt_lock' undeclared (first use in this
make[3]: *** [drivers/watchdog/ixp4xx_wdt.o] Error 1
- at91rm9200_wdt: 2760600da2
CC drivers/watchdog/at91rm9200_wdt.o
at91rm9200_wdt.c:188: error: 'at91_wdt_ioctl' undeclared here (not in a
make[3]: *** [drivers/watchdog/at91rm9200_wdt.o] Error 1
- wdt285: d0e58eed05
CC [M] drivers/watchdog/wdt285.o
wdt285.c: In function 'footbridge_watchdog_init':
wdt285.c:211: error: 'KERN_WARN' undeclared (first use in this function)
wdt285.c:211: error: (Each undeclared identifier is reported only once
wdt285.c:211: error: for each function it appears in.)
wdt285.c:212: error: expected ')' before string constant
make[3]: *** [drivers/watchdog/wdt285.o] Error 1
And this patch from rmk:
- s3c2410_wdt: 41dc8b72e3
CC drivers/watchdog/s3c2410_wdt.o
s3c2410_wdt.c: In function `s3c2410wdt_start':
s3c2410_wdt.c:161: warning: `return' with a value, in function returning void
Reported-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Looks like somebody didn't get enough sleep.
Noticed-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This brings the watchdog drivers into line with coding style.
This patch takes cares of the indentation as described in chapter 1.
Main changes:
* Re-structure the ioctl switch call for all drivers as follows:
switch (cmd) {
case WDIOC_GETSUPPORT:
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
case WDIOC_GETTEMP:
case WDIOC_SETOPTIONS:
case WDIOC_KEEPALIVE:
case WDIOC_SETTIMEOUT:
case WDIOC_GETTIMEOUT:
case WDIOC_GETTIMELEFT:
default:
}
This to make the migration from the drivers to the uniform watchdog
device driver easier in the future.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Kill off use of semaphores.
Fix ioctl races and locking holes.
From: Alan Cox <alan@redhat.com>
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>
Doug Anderson