mm,hwpoison-inject: don't pin for hwpoison_filter

Another memory error injection interface debugfs:hwpoison/corrupt-pfn also
takes bogus refcount for hwpoison_filter().  It's justified because this
does a coarse filter, expecting that memory_failure() redoes the check for
sure.

Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-4-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index e488876..1ae1ebc 100644 (file)
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -26,11 +26,6 @@ static int hwpoison_inject(void *data, u64 val)
 
        p = pfn_to_page(pfn);
        hpage = compound_head(p);
-       /*
-        * This implies unable to support free buddy pages.
-        */
-       if (!get_hwpoison_page(p))
-               return 0;
 
        if (!hwpoison_filter_enable)
                goto inject;
@@ -40,23 +35,20 @@ static int hwpoison_inject(void *data, u64 val)
         * This implies unable to support non-LRU pages.
         */
        if (!PageLRU(hpage) && !PageHuge(p))
-               goto put_out;
+               return 0;
 
        /*
-        * do a racy check with elevated page count, to make sure PG_hwpoison
-        * will only be set for the targeted owner (or on a free page).
+        * do a racy check to make sure PG_hwpoison will only be set for
+        * the targeted owner (or on a free page).
         * memory_failure() will redo the check reliably inside page lock.
         */
        err = hwpoison_filter(hpage);
        if (err)
-               goto put_out;
+               return 0;
 
 inject:
        pr_info("Injecting memory failure at pfn %#lx\n", pfn);
-       return memory_failure(pfn, MF_COUNT_INCREASED);
-put_out:
-       put_hwpoison_page(p);
-       return 0;
+       return memory_failure(pfn, 0);
 }
 
 static int hwpoison_unpoison(void *data, u64 val)