Alexander Gordeev
3003d55b59
pps: fix race in PPS_FETCH handler ...
There was a race in PPS_FETCH ioctl handler when several processes want to
obtain PPS data simultaneously using sleeping PPS_FETCH. They all sleep
most of the time in the system call.
With the old approach when the first process waiting on the pps queue is
waken up it makes new system call right away and zeroes pps->go. So other
processes continue to sleep. This is a clear race condition because of
the global 'go' variable.
With the new approach pps->last_ev holds some value increasing at each PPS
event. PPS_FETCH ioctl handler saves current value to the local variable
at the very beginning so it can safely check that there is a new event by
just comparing both variables.
Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:19 -08:00
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2011-01-07 17:02:58 -08:00
Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
2011-01-10 08:22:33 -08:00
Madge Ambassador ATM Adapter driver: Always release_firmware() in ucode_init() and don't leak memory.
2011-01-09 15:45:48 -08:00
Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
2011-01-10 16:10:33 -08:00
Merge branch 'stable/xenbus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
2011-01-12 08:37:35 -08:00
cs5535: deprecate older cs5535_gpio driver
2011-01-13 08:03:13 -08:00
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2011-01-07 17:02:58 -08:00
dca: remove unneeded NULL check
2011-01-13 08:03:09 -08:00
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
2011-01-11 16:31:41 -08:00
Merge branch 'mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp
2011-01-07 14:54:03 -08:00
gpio/ml_ioh_gpio: ML7213 GPIO driver
2011-01-13 08:03:14 -08:00
drm/i915/execbuffer: Reorder binding of objects to favour restrictions
2011-01-11 22:55:48 +00:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
2011-01-10 08:15:37 -08:00
hwmon: Support for Dallas Semiconductor DS620
2011-01-09 09:10:10 -08:00
i2c: Constify i2c_client where possible
2011-01-10 22:11:23 +01:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband
2011-01-11 16:30:08 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
2011-01-10 08:15:37 -08:00
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2011-01-07 16:58:04 -08:00
leds: add output inversion option to backlight trigger
2011-01-13 08:03:06 -08:00
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
2011-01-11 16:31:41 -08:00
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2011-01-07 16:58:04 -08:00
mfd: sh_mobile_sdhi: activate SDIO IRQ for tmio_mmc
2011-01-08 23:52:31 -05:00
Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6
2011-01-10 08:57:03 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
2011-01-11 11:01:24 -08:00
kmsg_dump: constrain mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC
2011-01-13 08:03:07 -08:00
Merge branch 'stable/xenbus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
2011-01-12 08:37:35 -08:00
NFC: Driver for NXP Semiconductors PN544 NFC chip.
2011-01-13 08:03:19 -08:00
Merge remote branch 'gcl/next' into next
2011-01-11 15:10:08 +11:00
Merge branch 'stable/xenbus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
2011-01-12 08:37:35 -08:00
Merge branch 'devel-stable' into devel
2011-01-06 22:33:32 +00:00
sony-laptop: support new hotkeys on the P, Z and EC series
2011-01-10 12:00:22 -05:00
pps: fix race in PPS_FETCH handler
2011-01-13 08:03:19 -08:00
rapidio: add new idt sRIO switches
2011-01-13 08:03:18 -08:00
rtc: rtc-max6902 - set driver data in max6902_probe()
2011-01-13 08:03:12 -08:00
headers: kobject.h redux
2011-01-10 08:51:44 -08:00
Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
2011-01-10 08:22:33 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin
2011-01-10 17:06:08 -08:00
headers: kobject.h redux
2011-01-10 08:51:44 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
2011-01-10 08:14:53 -08:00
cs5535: deprecate older cs5535_gpio driver
2011-01-13 08:03:13 -08:00
drivers/telephony/ixj.c: fix warning
2011-01-13 08:03:15 -08:00
Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
2011-01-07 14:39:20 -08:00
Merge branch 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6
2011-01-10 16:04:53 -08:00
vgacon: check for efi machine
2011-01-13 08:03:12 -08:00
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2011-01-11 11:02:13 -08:00
Merge branch 'stable/xenbus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
2011-01-12 08:37:35 -08:00
NFC: Driver for NXP Semiconductors PN544 NFC chip.
2011-01-13 08:03:19 -08:00
NFC: Driver for NXP Semiconductors PN544 NFC chip.
2011-01-13 08:03:19 -08:00
3003d55b59