[PATCH 2/4] x86/P2M: un-indent write_p2m_entry()

[Jan Beulich <jbeulich@xxxxxxxx>]

Drop the inner scope that was left from earlier if/else removal. Take
the opportunity and make the paging_unlock() invocation common to
success and error paths, though.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -110,49 +110,43 @@ static int write_p2m_entry(struct p2m_do
                            unsigned int level)
 {
     struct domain *d = p2m->domain;
-
+    unsigned int oflags;
+    mfn_t omfn;
+    int rc;
+
+    paging_lock(d);
+
+    if ( p2m->write_p2m_entry_pre && gfn != gfn_x(INVALID_GFN) )
+        p2m->write_p2m_entry_pre(d, gfn, *p, new, level);
+
+    oflags = l1e_get_flags(*p);
+    omfn = l1e_get_mfn(*p);
+
+    rc = p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
+                          p2m_flags_to_type(oflags), l1e_get_mfn(new),
+                          omfn, level);
+    if ( !rc )
     {
-        unsigned int oflags;
-        mfn_t omfn;
-        int rc;
-
-        paging_lock(d);
-
-        if ( p2m->write_p2m_entry_pre && gfn != gfn_x(INVALID_GFN) )
-            p2m->write_p2m_entry_pre(d, gfn, *p, new, level);
-
-        oflags = l1e_get_flags(*p);
-        omfn = l1e_get_mfn(*p);
-
-        rc = p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
-                              p2m_flags_to_type(oflags), l1e_get_mfn(new),
-                              omfn, level);
-        if ( rc )
-        {
-            paging_unlock(d);
-            return rc;
-        }
-
         safe_write_pte(p, new);
 
         if ( p2m->write_p2m_entry_post )
             p2m->write_p2m_entry_post(p2m, oflags);
+    }
 
-        paging_unlock(d);
+    paging_unlock(d);
 
-        if ( nestedhvm_enabled(d) && !p2m_is_nestedp2m(p2m) &&
-             (oflags & _PAGE_PRESENT) &&
-             !p2m_get_hostp2m(d)->defer_nested_flush &&
-             /*
-              * We are replacing a valid entry so we need to flush nested p2ms,
-              * unless the only change is an increase in access rights.
-              */
-             (!mfn_eq(omfn, l1e_get_mfn(new)) ||
-              !perms_strictly_increased(oflags, l1e_get_flags(new))) )
-            p2m_flush_nestedp2m(d);
-    }
+    if ( !rc && nestedhvm_enabled(d) && !p2m_is_nestedp2m(p2m) &&
+         (oflags & _PAGE_PRESENT) &&
+         !p2m_get_hostp2m(d)->defer_nested_flush &&
+         /*
+          * We are replacing a valid entry so we need to flush nested p2ms,
+          * unless the only change is an increase in access rights.
+          */
+         (!mfn_eq(omfn, l1e_get_mfn(new)) ||
+          !perms_strictly_increased(oflags, l1e_get_flags(new))) )
+        p2m_flush_nestedp2m(d);
 
-    return 0;
+    return rc;
 }
 
 // Find the next level's P2M entry, checking for out-of-range gfn's...