x86: cpa, strict range check in try_preserve_large_page()
[sfrench/cifs-2.6.git] / arch / x86 / mm / pageattr.c
index e5d29a112d002f04898a9d32994cf1d4aefc0f17..440210a2277d3d6a710dcb713792e377f8306d89 100644 (file)
@@ -253,10 +253,10 @@ static int
 try_preserve_large_page(pte_t *kpte, unsigned long address,
                        struct cpa_data *cpa)
 {
-       unsigned long nextpage_addr, numpages, pmask, psize, flags;
+       unsigned long nextpage_addr, numpages, pmask, psize, flags, addr;
        pte_t new_pte, old_pte, *tmp;
        pgprot_t old_prot, new_prot;
-       int do_split = 1;
+       int i, do_split = 1;
        unsigned int level;
 
        spin_lock_irqsave(&pgd_lock, flags);
@@ -303,6 +303,19 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
        pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
        new_prot = static_protections(new_prot, address);
 
+       /*
+        * We need to check the full range, whether
+        * static_protection() requires a different pgprot for one of
+        * the pages in the range we try to preserve:
+        */
+       addr = address + PAGE_SIZE;
+       for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE) {
+               pgprot_t chk_prot = static_protections(new_prot, addr);
+
+               if (pgprot_val(chk_prot) != pgprot_val(new_prot))
+                       goto out_unlock;
+       }
+
        /*
         * If there are no changes, return. maxpages has been updated
         * above: