arm: mm: Don't free prohibited memmap entries

The VM subsystem assumes that there are valid memmap entries to
the bank end aligned to MAX_ORDER_NR_PAGES. It will try and read
these page structs, and so we cannot free any memmap entries that
it may inspect.

Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index f6a9994..e18c7ce 100644 (file)
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -495,28 +495,27 @@ static void __init free_unused_memmap_node(int node, struct meminfo *mi)
        unsigned int i;
 
        /*
-        * [FIXME] This relies on each bank being in address order.  This
-        * may not be the case, especially if the user has provided the
-        * information on the command line.
+        * This relies on each bank being in address order.
+        * The banks are sorted previously in bootmem_init().
         */
        for_each_nodebank(i, mi, node) {
                struct membank *bank = &mi->bank[i];
 
                bank_start = bank_pfn_start(bank);
-               if (bank_start < prev_bank_end) {
-                       printk(KERN_ERR "MEM: unordered memory banks.  "
-                               "Not freeing memmap.\n");
-                       break;
-               }
 
                /*
                 * If we had a previous bank, and there is a space
                 * between the current bank and the previous, free it.
                 */
-               if (prev_bank_end && prev_bank_end != bank_start)
+               if (prev_bank_end && prev_bank_end < bank_start)
                        free_memmap(node, prev_bank_end, bank_start);
 
-               prev_bank_end = bank_pfn_end(bank);
+               /*
+                * Align up here since the VM subsystem insists that the
+                * memmap entries are valid from the bank end aligned to
+                * MAX_ORDER_NR_PAGES.
+                */
+               prev_bank_end = ALIGN(bank_pfn_end(bank), MAX_ORDER_NR_PAGES);
        }
 }