[IA64] Fix another IA64 preemption problem

There's another problem shown up by Ingo's recent patch to make
smp_processor_id() complain if it's called with preemption enabled.
local_finish_flush_tlb_mm() calls activate_context() in a situation
where it could be rescheduled to another processor.  This patch
disables preemption around the call.

Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 6 insertions, 0 deletions

diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index b49d4ddaab93..0166a9847095 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -231,13 +231,16 @@ smp_flush_tlb_all (void)
 void
 smp_flush_tlb_mm (struct mm_struct *mm)
 {
+        preempt_disable();
         /* this happens for the common case of a single-threaded fork():  */
         if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
         {
                 local_finish_flush_tlb_mm(mm);
+                preempt_enable();
                 return;
         }
 
+        preempt_enable();
         /*
          * We could optimize this further by using mm->cpu_vm_mask to track which CPUs
          * have been running in the address space.  It's not clear that this is worth the
diff --git a/include/asm-ia64/mmu_context.h b/include/asm-ia64/mmu_context.h
index 0096e7e05012..e3e5fededb04 100644
--- a/include/asm-ia64/mmu_context.h
+++ b/include/asm-ia64/mmu_context.h
@@ -132,6 +132,9 @@ reload_context (mm_context_t context)
         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 }
 
+/*
+ * Must be called with preemption off
+ */
 static inline void
 activate_context (struct mm_struct *mm)
 {