[Xen-devel] [PATCH 3/4] x86: reduce code duplication in guest_remove_page()

["Jan Beulich" <JBeulich@xxxxxxxx>]

Quite a bit of duplicate code has accumulated on the "paging" types
special case path. Re-use what can be re-used from the common path.

Since it needs touching anyway, slightly re-format and extend the
gdprintk() on the common path as well.

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

--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -320,30 +320,15 @@ int guest_remove_page(struct domain *d,
         if ( p2mt == p2m_ram_paging_out )
         {
             ASSERT(mfn_valid(mfn));
-            page = mfn_to_page(mfn);
-            rc = -ENXIO;
-            if ( !get_page(page, d) )
-                goto out_put_gfn;
+            goto obtain_page;
         }
-        else
-            page = NULL;
 
         rc = guest_physmap_remove_page(d, _gfn(gmfn), mfn, 0);
         if ( rc )
-        {
-            if ( page )
-                put_page(page);
             goto out_put_gfn;
-        }
 
         put_gfn(d, gmfn);
 
-        if ( page )
-        {
-            if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
-                put_page(page);
-            put_page(page);
-        }
         p2m_mem_paging_drop_page(d, gmfn, p2mt);
 
         return 0;
@@ -385,11 +370,16 @@ int guest_remove_page(struct domain *d,
     }
 #endif /* CONFIG_X86 */
 
+ obtain_page: __maybe_unused;
     page = mfn_to_page(mfn);
     if ( unlikely(!get_page(page, d)) )
     {
         put_gfn(d, gmfn);
-        gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id);
+#ifdef CONFIG_X86
+        if ( !p2m_is_paging(p2mt) )
+#endif
+            gdprintk(XENLOG_INFO, "Bad page free for Dom%u GFN %lx\n",
+                     d->domain_id, gmfn);
 
         return -ENXIO;
     }





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