mm: /proc/pid/pagemap: inspect _PAGE_SOFT_DIRTY only on present pages

commit e9cdd6e771580e6ff872e5c64e8b766972c7d1bc upstream.

If a page we are inspecting is in swap we may occasionally report it as
having soft dirty bit (even if it is clean).  The pte_soft_dirty helper
should be called on present pte only.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 107d026f5d6e0cbebc068fce65f201f167c425c5..7a9e255f195d50fd0a6a897532c2320a9cf5add8 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -938,6 +938,8 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
                frame = pte_pfn(pte);
                flags = PM_PRESENT;
                page = vm_normal_page(vma, addr, pte);
+               if (pte_soft_dirty(pte))
+                       flags2 |= __PM_SOFT_DIRTY;
        } else if (is_swap_pte(pte)) {
                swp_entry_t entry;
                if (pte_swp_soft_dirty(pte))
@@ -955,8 +957,6 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
 
        if (page && !PageAnon(page))
                flags |= PM_FILE;
-       if (pte_soft_dirty(pte))
-               flags2 |= __PM_SOFT_DIRTY;
 
        *pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
 }