[PATCH] sparsemem: fix crash in show_mem

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

Resend with proper subject. (old subject was "do not count pages in
holes with sparsemem"


With sparsemem, pfn should be checked by pfn_valid() before pfn_to_page().

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>

diff --git a/arch/mips/mm/pgtable.c b/arch/mips/mm/pgtable.c
index 792c6eb..c93aa6c 100644
--- a/arch/mips/mm/pgtable.c
+++ b/arch/mips/mm/pgtable.c
@@ -15,6 +15,8 @@ #ifndef CONFIG_NEED_MULTIPLE_NODES  /* X
        printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
        pfn = max_mapnr;
        while (pfn-- > 0) {
+               if (!pfn_valid(pfn))
+                       continue;
                page = pfn_to_page(pfn);
                total++;
                if (PageHighMem(page))