Merge branch 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj...

[firefly-linux-kernel-4.4.55.git] / arch / x86 / mm / pat.c

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index f11729fd019c6899e61e2989ed17a1619a46239d..3d68ef6d2266cb66b3d07c578191b80c5348e0e2 100644 (file)
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -158,31 +158,47 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
        return req_type;
 }
 
+struct pagerange_state {
+       unsigned long           cur_pfn;
+       int                     ram;
+       int                     not_ram;
+};
+
+static int
+pagerange_is_ram_callback(unsigned long initial_pfn, unsigned long total_nr_pages, void *arg)
+{
+       struct pagerange_state *state = arg;
+
+       state->not_ram  |= initial_pfn > state->cur_pfn;
+       state->ram      |= total_nr_pages > 0;
+       state->cur_pfn   = initial_pfn + total_nr_pages;
+
+       return state->ram && state->not_ram;
+}
+
 static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
 {
-       int ram_page = 0, not_rampage = 0;
-       unsigned long page_nr;
+       int ret = 0;
+       unsigned long start_pfn = start >> PAGE_SHIFT;
+       unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+       struct pagerange_state state = {start_pfn, 0, 0};
 
-       for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
-            ++page_nr) {
-               /*
-                * For legacy reasons, physical address range in the legacy ISA
-                * region is tracked as non-RAM. This will allow users of
-                * /dev/mem to map portions of legacy ISA region, even when
-                * some of those portions are listed(or not even listed) with
-                * different e820 types(RAM/reserved/..)
-                */
-               if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
-                   page_is_ram(page_nr))
-                       ram_page = 1;
-               else
-                       not_rampage = 1;
-
-               if (ram_page == not_rampage)
-                       return -1;
+       /*
+        * For legacy reasons, physical address range in the legacy ISA
+        * region is tracked as non-RAM. This will allow users of
+        * /dev/mem to map portions of legacy ISA region, even when
+        * some of those portions are listed(or not even listed) with
+        * different e820 types(RAM/reserved/..)
+        */
+       if (start_pfn < ISA_END_ADDRESS >> PAGE_SHIFT)
+               start_pfn = ISA_END_ADDRESS >> PAGE_SHIFT;
+
+       if (start_pfn < end_pfn) {
+               ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
+                               &state, pagerange_is_ram_callback);
        }
 
-       return ram_page;
+       return (ret > 0) ? -1 : (state.ram ? 1 : 0);
 }
 
 /*