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c4e773764c
android_kernel_xiaomi_sm8350/drivers
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Stefani Seibold c4e773764c mtd: fix a huge latency problem in the MTD CFI and LPDDR flash drivers. 
The use of a memcpy() during a spinlock operation will cause very long
thread context switch delays if the flash chip bandwidth is low and the
data to be copied large, because a spinlock will disable preemption.

For example: A flash with 6,5 MB/s bandwidth will cause under ubifs,
which request sometimes 128 KiB (the flash erase size), a preemption delay of
20 milliseconds. High priority threads will not be served during this
time, regardless whether this threads access the flash or not. This behavior
breaks real time.

The patch changes all the use of spin_lock operations for xxxx->mutex
into mutex operations, which is exact what the name says and means.

I have checked the code of the drivers and there is no use of atomic
pathes like interrupt or timers. The mtdoops facility will also not be used
by this drivers. So it is dave to replace the spin_lock against mutex.

There is no performance regression since the mutex is normally not
acquired.

Changelog:
 06.03.2010 First release
 26.03.2010 Fix mutex[1] issue and tested it for compile failure

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-05-10 14:22:30 +01:00
..
accessibility
acpi backlight: Allow properties to be passed at registration 2010-03-16 19:47:54 +00:00
amba
ata ahci: pp->active_link is not reliable when FBS is enabled 2010-03-17 15:54:55 -04:00
atm atm: use for_each_set_bit() 2010-03-15 16:00:47 -07:00
auxdisplay auxdisplay: move cfag12864bfb's probe function to .devinit.text 2010-03-07 17:04:50 -08:00
base Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2010-03-19 13:39:42 -07:00
block Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-03-12 16:04:50 -08:00
bluetooth
cdrom
char Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2010-03-19 13:40:03 -07:00
clocksource
connector
cpufreq Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
cpuidle Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
crypto Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
dca
dio
dma Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-03-12 16:04:50 -08:00
edac edac: e752x: add dram scrubbing support 2010-03-12 15:52:40 -08:00
eisa
firewire Driver core: create lock/unlock functions for struct device 2010-03-07 17:04:52 -08:00
firmware Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
gpio driver-core: Add attribute argument to class_attribute show/store 2010-03-07 17:04:48 -08:00
gpu backlight: Allow properties to be passed at registration 2010-03-16 19:47:54 +00:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2010-03-18 16:52:31 -07:00
hwmon
i2c Add include to i2c-xii.c to fix build error 2010-03-14 11:14:58 -07:00
ide
idle
ieee1394 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-03-12 16:04:50 -08:00
ieee802154
infiniband Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2010-03-19 13:39:42 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-03-14 11:13:54 -07:00
isdn gigaset: fix build failure 2010-03-17 14:22:07 -07:00
leds leds: Fix race between LED device uevent and actual attributes creation 2010-03-16 20:27:25 +00:00
lguest
macintosh backlight: Allow properties to be passed at registration 2010-03-16 19:47:54 +00:00
mca
md Merge branch 'for-linus' of git://neil.brown.name/md 2010-03-18 16:55:24 -07:00
media Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-03-14 11:13:54 -07:00
memstick
message Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
mfd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6 2010-03-12 16:41:09 -08:00
misc init dynamic bin_attribute structures 2010-03-14 20:28:39 -07:00
mmc Merge branch 'msm-mmc_sdcc' of git://codeaurora.org/quic/kernel/dwalker/linux-msm 2010-03-12 16:21:24 -08:00
mtd mtd: fix a huge latency problem in the MTD CFI and LPDDR flash drivers. 2010-05-10 14:22:30 +01:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2010-03-19 13:39:42 -07:00
nubus
of
oprofile
parisc Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
parport Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
pci Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2010-03-19 13:39:42 -07:00
pcmcia PCMCIA: resource, fix lock imbalance 2010-03-16 17:54:58 +01:00
platform backlight: panasonic-laptop - Fix incomplete registration failure handling 2010-03-16 20:13:31 +00:00
pnp PNPACPI: add bus number support 2010-03-14 20:08:38 -04:00
power Merge branches 'battery-2.6.34', 'bugzilla-10805', 'bugzilla-14668', 'bugzilla-531916-power-state', 'ht-warn-2.6.34', 'pnp', 'processor-rename', 'sony-2.6.34', 'suse-bugzilla-531547', 'tz-check', 'video' and 'misc-2.6.34' into release 2010-03-14 21:30:17 -04:00
pps pps: serial clients support 2010-03-12 15:52:43 -08:00
ps3
rapidio
regulator
rtc init dynamic bin_attribute structures 2010-03-14 20:28:39 -07:00
s390 memory hotplug/s390: set phys_device 2010-03-17 18:43:47 -07:00
sbus
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2010-03-18 16:54:31 -07:00
serial Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 2010-03-19 18:16:20 -07:00
sfi
sh Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 2010-03-19 18:16:20 -07:00
sn
spi Merge branch 'merge' of git://git.secretlab.ca/git/linux-2.6 2010-03-18 17:01:19 -07:00
ssb
staging backlight: Allow properties to be passed at registration 2010-03-16 19:47:54 +00:00
tc
telephony
thermal
uio UIO: Remove SMX Cryptengine driver 2010-03-07 17:04:51 -08:00
usb Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2010-03-19 13:40:03 -07:00
uwb Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/dvrabel/uwb 2010-03-19 18:14:22 -07:00
vhost
video Merge master.kernel.org:/home/rmk/linux-2.6-arm 2010-03-18 16:59:10 -07:00
virtio
vlynq
w1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-03-12 16:04:50 -08:00
watchdog [WATCHDOG] i6300esb.c: change platform_driver to pci_driver 2010-03-08 13:48:01 +00:00
xen Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
zorro
Kconfig
Makefile Merge branch 'origin' into devel-stable 2010-03-08 20:21:04 +00:00