linux/arch/sparc
Thomas Gleixner ea875ec94e sparc/sysfs: Replace racy task affinity logic
The mmustat_enable sysfs file accessor functions must run code on the
target CPU. This is achieved by temporarily setting the affinity of the
calling user space thread to the requested CPU and reset it to the original
affinity afterwards.

That's racy vs. concurrent affinity settings for that thread resulting in
code executing on the wrong CPU and overwriting the new affinity setting.

Replace it by using work_on_cpu() which guarantees to run the code on the
requested CPU.

Protection against CPU hotplug is not required as the open sysfs file
already prevents the removal from the CPU offline callback. Using the
hotplug protected version would actually be wrong because it would deadlock
against a CPU hotplug operation of the CPU associated to the sysfs file in
progress.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: herbert@gondor.apana.org.au
Cc: rjw@rjwysocki.net
Cc: peterz@infradead.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: jiangshanlai@gmail.com
Cc: sparclinux@vger.kernel.org
Cc: viresh.kumar@linaro.org
Cc: mpe@ellerman.id.au
Cc: tj@kernel.org
Cc: lenb@kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704131001270.2408@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-15 12:20:54 +02:00
..
boot sparc: Add "install" target 2014-08-04 20:45:59 -07:00
configs sparc64:Support User Probes for sparc 2016-12-11 18:01:51 -08:00
crypto crypto: sparc - initialize blkcipher.ivsize 2015-10-08 21:36:48 +08:00
include sparc: remove unused wp_works_ok macro 2017-04-06 12:03:30 -07:00
kernel sparc/sysfs: Replace racy task affinity logic 2017-04-15 12:20:54 +02:00
lib arch/sparc: Avoid DCTI Couples 2017-03-27 21:51:40 -07:00
math-emu Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mm sparc32: Export vac_cache_size to fix build error 2017-04-06 12:03:30 -07:00
net sparc: Fix misspellings in comments. 2016-03-20 21:28:58 -07:00
oprofile
power Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2014-10-11 20:36:34 -04:00
prom sparc: fixing ident and beautifying code 2016-10-06 01:46:40 -04:00
Kbuild
Kconfig net:add one common config ARCH_WANT_RELAX_ORDER to support relax ordering 2017-01-18 16:33:00 -05:00
Kconfig.debug
Makefile sparc32: Add -Wa,-Av8 to KBUILD_CFLAGS. 2016-03-01 00:24:04 -05:00