x86: reorganize cpa_process_alias()

Reorganize cpa_process_alias() so that new alias condition can be
added easily.

Jan Beulich spotted problem in the original cleanup thread which
incorrectly assumed the two existing conditions were mutially
exclusive.

[ Impact: code reorganization ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>

1 files changed, 23 insertions, 27 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 3cfe9ced8a4c..2ab058b0947d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -681,8 +681,9 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias);
 static int cpa_process_alias(struct cpa_data *cpa)
 {
         struct cpa_data alias_cpa;
-        int ret = 0;
-        unsigned long temp_cpa_vaddr, vaddr;
+        unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT);
+        unsigned long vaddr;
+        int ret;
 
         if (cpa->pfn >= max_pfn_mapped)
                 return 0;
@@ -706,42 +707,37 @@ static int cpa_process_alias(struct cpa_data *cpa)
                     PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT)))) {
 
                 alias_cpa = *cpa;
-                temp_cpa_vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT);
-                alias_cpa.vaddr = &temp_cpa_vaddr;
+                alias_cpa.vaddr = &laddr;
                 alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
 
-
                 ret = __change_page_attr_set_clr(&alias_cpa, 0);
+                if (ret)
+                        return ret;
         }
 
 #ifdef CONFIG_X86_64
-        if (ret)
-                return ret;
         /*
-         * No need to redo, when the primary call touched the high
-         * mapping already:
-         */
-        if (within(vaddr, (unsigned long) _text, _brk_end))
-                return 0;
-
-        /*
-         * If the physical address is inside the kernel map, we need
+         * If the primary call didn't touch the high mapping already
+         * and the physical address is inside the kernel map, we need
          * to touch the high mapped kernel as well:
          */
-        if (!within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn()))
-                return 0;
-
-        alias_cpa = *cpa;
-        temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + __START_KERNEL_map - phys_base;
-        alias_cpa.vaddr = &temp_cpa_vaddr;
-        alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
+        if (!within(vaddr, (unsigned long)_text, _brk_end) &&
+            within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn())) {
+                unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) +
+                                               __START_KERNEL_map - phys_base;
+                alias_cpa = *cpa;
+                alias_cpa.vaddr = &temp_cpa_vaddr;
+                alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
 
-        /*
-         * The high mapping range is imprecise, so ignore the return value.
-         */
-        __change_page_attr_set_clr(&alias_cpa, 0);
+                /*
+                 * The high mapping range is imprecise, so ignore the
+                 * return value.
+                 */
+                __change_page_attr_set_clr(&alias_cpa, 0);
+        }
 #endif
-        return ret;
+
+        return 0;
 }
 
 static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias)