[PATCH v3 05/15] mm,hwpoison-inject: don't pin for hwpoison_filter

nao.horiguchi
2020-06-24T15:02:53Z

From: Naoya Horiguchi <naoya.horiguchi@nec.com>

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>
---
mm/hwpoison-inject.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)

diff --git v5.8-rc1-mmots-2020-06-20-21-44/mm/hwpoison-inject.c v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/hwpoison-inject.c
index e488876b168a..1ae1ebc2b9b1 100644
--- v5.8-rc1-mmots-2020-06-20-21-44/mm/hwpoison-inject.c
+++ v5.8-rc1-mmots-2020-06-20-21-44_patched/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)
--
2.17.1