xen, cpupools: Fix cpupool-move to make more consistent

The full order for creating new private data structures when moving
from one pool to another is now:
* Allocate all new structures
 - Allocate a new private domain structure (but don't point there yet)
 - Allocate per-vcpu data structures (but don't point there yet)
* Remove old structures
 - Remove each vcpu, freeing the associated data structure
 - Free the domain data structure
* Switch to the new structures
 - Set the domain to the new cpupool, with the new private domain
 structure
 - Set each vcpu to the respective new structure, and insert

This is in line with a (fairly reasonable) assumption in credit2 that
the private structure of the domain will be the private structure
pointed to by the per-vcpu private structure.

Also fix a bug, in which insert_vcpu was called with the *old* vcpu
ops rather than the new ones.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Committed-by: Keir Fraser <keir@xen.org>

xen/common/schedule.c

@@ -261,6 +261,18 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
 
     domain_pause(d);
 
+    for_each_vcpu ( d, v )
+    {
+        SCHED_OP(VCPU2OP(v), remove_vcpu, v);
+        SCHED_OP(VCPU2OP(v), free_vdata, v->sched_priv);
+        v->sched_priv = NULL;
+    }
+
+    SCHED_OP(DOM2OP(d), free_domdata, d->sched_priv);
+
+    d->cpupool = c;
+    d->sched_priv = domdata;
+
     new_p = cpumask_first(c->cpu_valid);
     for_each_vcpu ( d, v )
     {
@@ -268,9 +280,6 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
         migrate_timer(&v->singleshot_timer, new_p);
         migrate_timer(&v->poll_timer, new_p);
 
-        SCHED_OP(VCPU2OP(v), remove_vcpu, v);
-        SCHED_OP(VCPU2OP(v), free_vdata, v->sched_priv);
-
         cpumask_setall(v->cpu_affinity);
         v->processor = new_p;
         v->sched_priv = vcpu_priv[v->vcpu_id];
@@ -278,13 +287,9 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
 
         new_p = cpumask_cycle(new_p, c->cpu_valid);
 
-        SCHED_OP(VCPU2OP(v), insert_vcpu, v);
+        SCHED_OP(c->sched, insert_vcpu, v);
     }
 
-    d->cpupool = c;
-    SCHED_OP(DOM2OP(d), free_domdata, d->sched_priv);
-    d->sched_priv = domdata;
-
     domain_update_node_affinity(d);
 
     domain_unpause(d);