tree 4cbc38474b5ab6dfe8591f0b490686315a6aaa26
parent 7b6666530e2736f190a2629c8abe34275054449f
author John Hawkes <hawkes@sgi.com> 1134756024 -0800
committer Tony Luck <tony.luck@intel.com> 1134756024 -0800

[IA64] disable preemption in udelay()

The udelay() inline for ia64 uses the ITC.  If CONFIG_PREEMPT is enabled
and the platform has unsynchronized ITCs and the calling task migrates
to another CPU while doing the udelay loop, then the effective delay may
be too short or very, very long.

This patch disables preemption around 100 usec chunks of the overall
desired udelay time.  This minimizes preemption-holdoffs.

udelay() is now too big to be inline, move it out of line and export it.

Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>