Lars-Peter Clausen b91accafbb iio:event: Fix and cleanup locking ... The event code currently holds a spinlock with IRQs disabled while calling kfifo_to_user(). kfifo_to_user() can generate a page fault though, which means we have to be able to sleep, which is not possible if the interrupts are disabled. The good thing is that kfifo handles concurrent read and write access just fine as long as there is only one reader and one writer, so we do not any locking to protect against concurrent access from the read and writer thread. It is possible though that userspace is trying to read from the event FIFO from multiple concurrent threads, so we need to add locking to protect against this. This is done using a mutex. The mutex will only protect the kfifo_to_user() call, it will not protect the waitqueue. This means that multiple threads can be waiting for new data and once a new event is added to the FIFO all waiting threads will be woken up. If one of those threads is unable to read any data (because another thread already read all the data) it will go back to sleep. The only remaining issue is that now that the clearing of the BUSY flag and the emptying of the FIFO does no longer happen in one atomic step it is possible that a event is added to the FIFO after it has been emptied and this sample will be visible the next time a new event file descriptor is created. To avoid this rather move the emptying of the FIFO from iio_event_chrdev_release to iio_event_getfd(). Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>		2014-02-23 15:53:25 +00:00
..
accessibility
acpi	Merge branches 'acpi-processor', 'acpi-hotplug', 'acpi-init', 'acpi-pm' and 'acpica'	2014-01-29 11:47:18 +01:00
amba
ata	ACPI and power management updates for 3.14-rc1	2014-01-24 15:51:02 -08:00
atm
auxdisplay
base	regmap: Updates for v3.14	2014-01-25 13:18:00 -08:00
bcma	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2014-01-30 17:20:32 -08:00
block	Bug-fixes:	2014-01-31 08:38:18 -08:00
bluetooth
bus	drivers: bus: fix CCI driver kcalloc call parameters swap	2014-01-31 15:15:13 -08:00
cdrom	Merge branch 'for-3.14/drivers' of git://git.kernel.dk/linux-block	2014-01-30 11:40:10 -08:00
char	ipmi: Add missing rv in ipmi_parisc_probe()	2014-01-30 10:02:54 -08:00
clk	The second half of the clock framework pull requeust for 3.14 is	2014-01-28 18:44:53 -08:00
clocksource	clocksource: kona: Add basic use of external clock	2014-01-31 21:04:01 -08:00
connector
cpufreq	ACPI and power management fixes and cleanups for 3.14-rc1	2014-01-31 09:23:52 -08:00
cpuidle	powerpc/powernv/cpuidle: Back-end cpuidle driver for powernv platform.	2014-01-29 17:02:24 +11:00
crypto	ARM: driver updates for 3.14	2014-01-23 18:49:36 -08:00
dca
devfreq	Merge branches 'pm-cpufreq' and 'pm-devfreq'	2014-01-29 11:48:23 +01:00
dio
dma	Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma	2014-01-29 20:27:23 -08:00
edac	Merge branch 'x86-ras-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-20 12:10:27 -08:00
eisa	Revert "EISA: Initialize device before its resources"	2014-01-17 14:57:29 -07:00
extcon
firewire	firewire: Enable remote DMA above 4 GB	2014-01-20 01:11:13 +01:00
firmware	firmware/google: drop 'select EFI' to avoid recursive dependency	2014-01-27 21:02:40 -08:00
fmc
gpio	ARM: driver updates for 3.14	2014-01-23 18:49:36 -08:00
gpu	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2014-01-29 20:49:12 -08:00
hid	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2014-01-31 09:31:14 -08:00
hsi
hv	hyperv: Add support for physically discontinuous receive buffer	2014-01-27 16:40:45 -08:00
hwmon	hwmon: Fix SENSORS_TMP102 dependencies to eliminate build errors	2014-02-02 17:59:07 +01:00
hwspinlock
i2c	Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux	2014-01-29 19:56:20 -08:00
ide	drivers: ide: Include appropriate header file in ide-pio-blacklist.c	2014-01-28 23:35:09 -08:00
idle	ACPI and power management updates for 3.14-rc1	2014-01-24 15:51:02 -08:00
iio	iio:event: Fix and cleanup locking	2014-02-23 15:53:25 +00:00
infiniband	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2014-01-31 15:31:23 -08:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2014-01-24 17:17:30 -08:00
iommu	IOMMU Updates for Linux v3.14	2014-01-29 20:00:13 -08:00
ipack
irqchip	mvebu fixes for v3.13 (incremental #2)	2014-01-31 14:59:28 -08:00
isdn	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-01-25 11:17:34 -08:00
leds	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds	2014-01-28 18:53:01 -08:00
lguest
macintosh	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc	2014-01-27 21:11:26 -08:00
mailbox	drivers/mailbox/omap: make mbox->irq signed for error handling	2014-01-23 16:36:53 -08:00
md	Merge branch 'for-3.14/drivers' of git://git.kernel.dk/linux-block	2014-01-30 11:40:10 -08:00
media	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2014-01-31 09:31:14 -08:00
memory
memstick	drivers/memstick/host/rtsx_pci_ms.c: fix ms card data transfer bug	2014-01-23 16:37:04 -08:00
message	Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block	2014-01-30 11:19:05 -08:00
mfd	regulator: Updates for v3.14	2014-01-25 13:19:10 -08:00
misc	Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging	2014-01-29 18:56:27 -08:00
mmc	MMC highlights for 3.14:	2014-01-26 11:00:41 -08:00
mtd	* Improve the NOR erasure quirk - now it tries to do as little writes as	2014-01-30 20:04:09 -08:00
net	Merge branch 'akpm' (patches from Andrew Morton)	2014-01-30 18:44:44 -08:00
nfc
ntb
nubus
of	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-01-25 11:17:34 -08:00
oprofile
parisc
parport	TTY/Serial driver patches for 3.14-rc1	2014-01-20 16:05:23 -08:00
pci	Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"	2014-02-01 10:24:31 -08:00
pcmcia	PCI changes for the v3.14 merge window:	2014-01-22 16:39:28 -08:00
phy	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-01-25 11:17:34 -08:00
pinctrl	ARM: SoC DT updates for 3.14	2014-01-23 18:45:38 -08:00
platform	platform/chrome: Cleanups and improvements	2014-01-29 20:06:01 -08:00
pnp
power	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-01-25 11:17:34 -08:00
powercap
pps
ps3
ptp
pwm	pwm: Changes for v3.14-rc1	2014-01-27 08:15:51 -08:00
rapidio
regulator	regulator: Updates for v3.14	2014-01-25 13:19:10 -08:00
remoteproc
reset
rpmsg
rtc	Merge branch 'akpm' (incoming from Andrew)	2014-01-23 19:11:50 -08:00
s390	Second batch of KVM updates. Some minor x86 fixes,	2014-01-31 08:37:32 -08:00
sbus	sparc: delete non-required instances of include <linux/init.h>	2014-01-28 23:38:23 -08:00
scsi	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2014-01-31 15:31:23 -08:00
sfi
sh
sn
spi	Merge remote-tracking branch 'agust/next' into next	2014-01-29 16:53:55 +11:00
ssb	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2014-01-30 17:20:32 -08:00
staging	staging:iio:ad799x use regulator for vref	2014-02-18 08:43:33 +00:00
target	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2014-01-31 15:31:23 -08:00
tc
thermal	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux	2014-01-24 17:13:49 -08:00
tty	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2014-01-30 17:20:32 -08:00
uio
usb	staging: usbip: convert usbip-host driver to usb_device_driver	2014-02-07 10:54:30 -08:00
uwb
vfio	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc	2014-01-27 21:11:26 -08:00
vhost	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2014-01-31 15:31:23 -08:00
video	parisc/sti_console: prefer Linux fonts over built-in ROM fonts	2014-02-02 20:56:47 +01:00
virt
virtio	A few simple fixes. Quiet cycle.	2014-01-22 22:24:35 -08:00
vlynq	drivers/vlynq/vlynq.c: fix another resource size off by 1 error	2014-01-23 16:36:55 -08:00
vme
w1	drivers/w1/masters/w1-gpio.c: add strong pullup emulation	2014-01-23 16:37:04 -08:00
watchdog	watchdog: w83627hf_wdt: Reset watchdog trigger during initialization	2014-01-28 21:35:40 +01:00
xen	Bug-fixes:	2014-01-31 08:38:18 -08:00
zorro
Kconfig
Makefile