s390/vtime: correct idle time calculation
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 28 Oct 2013 11:15:32 +0000 (12:15 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Thu, 31 Oct 2013 08:52:52 +0000 (09:52 +0100)
commit4560e7c3317c7a2b370e36dadd3a3bac2ed70818
treeb0fd4d8705f388783dd893a472105013b702991d
parent7ab64a85e1a009046f97413a573e83fd85f7804d
s390/vtime: correct idle time calculation

Use the ACCESS_ONCE macro for both accesses to idle->sequence in the
loops to calculate the idle time. If only one access uses the macro,
the compiler is free to cache the value for the second access which
can cause endless loops.

Cc: stable@vger.kernel.org # 3.6+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/smp.c
arch/s390/kernel/vtime.c