[Xen-changelog] [xen-unstable] stop_machine: Allow specified function to run on all CPUs.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxx>
# Date 1295014564 0
# Node ID 2d4fe1a048cd8ae4c8aa0a50f65d0211c8ecf4d2
# Parent  6c9bcfb0fb84c18dd65e2304309f4d857a1ca4d3
stop_machine: Allow specified function to run on all CPUs.

Signed-off-by: Keir Fraser <keir@xxxxxxx>
---
 xen/common/stop_machine.c      |   15 ++++++++++++---
 xen/include/xen/stop_machine.h |    2 +-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff -r 6c9bcfb0fb84 -r 2d4fe1a048cd xen/common/stop_machine.c
--- a/xen/common/stop_machine.c Fri Jan 14 14:07:39 2011 +0000
+++ b/xen/common/stop_machine.c Fri Jan 14 14:16:04 2011 +0000
@@ -61,6 +61,10 @@ static void stopmachine_set_state(enum s
     atomic_set(&stopmachine_data.done, 0);
     smp_wmb();
     stopmachine_data.state = state;
+}
+
+static void stopmachine_wait_state(void)
+{
     while ( atomic_read(&stopmachine_data.done) != stopmachine_data.nr_cpus )
         cpu_relax();
 }
@@ -101,16 +105,20 @@ int stop_machine_run(int (*fn)(void *), 
         tasklet_schedule_on_cpu(&per_cpu(stopmachine_tasklet, i), i);
 
     stopmachine_set_state(STOPMACHINE_PREPARE);
+    stopmachine_wait_state();
 
     local_irq_disable();
     stopmachine_set_state(STOPMACHINE_DISABLE_IRQ);
+    stopmachine_wait_state();
 
-    if ( cpu == smp_processor_id() )
+    stopmachine_set_state(STOPMACHINE_INVOKE);
+    if ( (cpu == smp_processor_id()) || (cpu == NR_CPUS) )
         stopmachine_data.fn_result = (*fn)(data);
-    stopmachine_set_state(STOPMACHINE_INVOKE);
+    stopmachine_wait_state();
     ret = stopmachine_data.fn_result;
 
     stopmachine_set_state(STOPMACHINE_EXIT);
+    stopmachine_wait_state();
     local_irq_enable();
 
     spin_unlock(&stopmachine_lock);
@@ -140,7 +148,8 @@ static void stopmachine_action(unsigned 
             local_irq_disable();
             break;
         case STOPMACHINE_INVOKE:
-            if ( stopmachine_data.fn_cpu == smp_processor_id() )
+            if ( (stopmachine_data.fn_cpu == smp_processor_id()) ||
+                 (stopmachine_data.fn_cpu == NR_CPUS) )
                 stopmachine_data.fn_result =
                     stopmachine_data.fn(stopmachine_data.fn_data);
             break;
diff -r 6c9bcfb0fb84 -r 2d4fe1a048cd xen/include/xen/stop_machine.h
--- a/xen/include/xen/stop_machine.h    Fri Jan 14 14:07:39 2011 +0000
+++ b/xen/include/xen/stop_machine.h    Fri Jan 14 14:16:04 2011 +0000
@@ -5,7 +5,7 @@
  * stop_machine_run: freeze the machine on all CPUs and run this function
  * @fn: the function to run
  * @data: the data ptr for the @fn()
- * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS).
+ * @cpu: the cpu to run @fn() on (or all, if @cpu == NR_CPUS).
  *
  * Description: This causes every other cpu to enter a safe point, with
  * each of which disables interrupts, and finally interrupts are disabled

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