[PATCH] xen: Fold exit paths in find_text_region()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Despite rcu_read_unlock() being fully inlineable, the optimiser cannot fold
these exit paths, because of the various compiler barriers providing RCU
safety.  Help the compiler out.

This compiles to marginally better code in all cases.  No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
---
 xen/common/virtual_region.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/xen/common/virtual_region.c b/xen/common/virtual_region.c
index 30b0b4ab9c85..5ecdba9c08ed 100644
--- a/xen/common/virtual_region.c
+++ b/xen/common/virtual_region.c
@@ -40,20 +40,20 @@ static DEFINE_RCU_READ_LOCK(rcu_virtual_region_lock);
 
 const struct virtual_region *find_text_region(unsigned long addr)
 {
-    const struct virtual_region *region;
+    const struct virtual_region *iter, *region = NULL;
 
     rcu_read_lock(&rcu_virtual_region_lock);
-    list_for_each_entry_rcu( region, &virtual_region_list, list )
+    list_for_each_entry_rcu ( iter, &virtual_region_list, list )
     {
-        if ( (void *)addr >= region->start && (void *)addr < region->end )
+        if ( (void *)addr >= iter->start && (void *)addr < iter->end )
         {
-            rcu_read_unlock(&rcu_virtual_region_lock);
-            return region;
+            region = iter;
+            break;
         }
     }
     rcu_read_unlock(&rcu_virtual_region_lock);
 
-    return NULL;
+    return region;
 }
 
 void register_virtual_region(struct virtual_region *r)
-- 
2.30.2