aha/arch
Gautham R Shenoy 51badebdcf powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate
Currently the cpu-allocation/deallocation process comprises of two steps:
- Set the indicators and to update the device tree with DLPAR node
  information.

- Online/offline the allocated/deallocated CPU.

This is achieved by writing to the sysfs tunables "probe" during allocation
and "release" during deallocation.

At the sametime, the userspace can independently online/offline the CPUs of
the system using the sysfs tunable "online".

It is quite possible that when a userspace tool offlines a CPU
for the purpose of deallocation and is in the process of updating the device
tree, some other userspace tool could bring the CPU back online by writing to
the "online" sysfs tunable thereby causing the deallocate process to fail.

The solution to this is to serialize writes to the "probe/release" sysfs
tunable with the writes to the "online" sysfs tunable.

This patch employs a mutex to provide this serialization, which is a no-op on
all architectures except PPC_PSERIES

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-12-09 17:09:36 +11:00
..
alpha Merge branch 'hostprogs-wmissing-prototypes' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux-misc 2009-11-17 09:14:49 -08:00
arm Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 2009-11-18 15:00:21 -08:00
avr32 at91: at91sam9g45 family: identify several chip versions 2009-11-03 18:42:31 +01:00
blackfin headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
cris const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
frv frv: fix check on unsigned in do_signal() 2009-10-29 07:39:32 -07:00
h8300 h8300: Cleanup linker script using new linker script macros. 2009-09-24 17:16:22 -07:00
ia64 Revert "[IA64] fix percpu warnings" 2009-11-02 09:23:08 -08:00
m32r m32r: fix arch/m32r/boot/compressed/Makefile 2009-11-09 09:00:50 +09:00
m68k tty: Mark generic_serial users as BROKEN 2009-10-30 14:43:12 -07:00
m68knommu m68knommu: fix rename of pt_regs offset defines breakage 2009-09-30 10:06:07 +10:00
microblaze microblaze: Clear sticky FSR register after saving it to func parametr 2009-10-05 11:37:47 +02:00
mips MIPS: SMTC: Fix lockup in smtc_distribute_timer 2009-11-13 18:10:38 +01:00
mn10300 mn10300: fix kernel build failures when using gcc-4.x 2009-10-01 16:11:12 -07:00
parisc fcntl: Use consistent values for F_[GS]ETOWN_EX 2009-11-17 09:13:43 -08:00
powerpc powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate 2009-12-09 17:09:36 +11:00
s390 [S390] s390: fix single stepping on svc0 2009-11-13 15:45:03 +01:00
score Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next 2009-09-23 15:37:02 -07:00
sh sh: Fixup last users of irq_chip->typename 2009-11-18 10:50:22 +09:00
sparc Merge branch 'hostprogs-wmissing-prototypes' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux-misc 2009-11-17 09:14:49 -08:00
um headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
x86 [CPUFREQ] speedstep-ich: fix error caused by 394122ab14 2009-11-17 23:15:04 -05:00
xtensa headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
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