[PATCH] memory: avoid pointless continuation in xenmem_add_to_physmap()

[Jan Beulich]

Adjust so we uniformly avoid needlessly arranging for a continuation on
the last iteration.

Fixes: 5777a3742d88 ("IOMMU: hold page ref until after deferred TLB flush")
Signed-off-by: Jan Beulich <jbeul...@suse.com>

--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -854,8 +854,9 @@ int xenmem_add_to_physmap(struct domain
             ++extra.ppage;
 
         /* Check for continuation if it's not the last iteration. */
-        if ( (++done >= ARRAY_SIZE(pages) && extra.ppage) ||
-             (xatp->size > done && hypercall_preempt_check()) )
+        if ( xatp->size > ++done &&
+             ((done >= ARRAY_SIZE(pages) && extra.ppage) ||
+              hypercall_preempt_check()) )
         {
             rc = start + done;
             break;