[PATCH v3 7/7] pmem: fix pmem_do_write() avoid writing to 'np' page

From: Jane Chu <jane.chu@oracle.com>
To: david@fromorbit.com, djwong@kernel.org, dan.j.williams@intel.com,
	hch@infradead.org, vishal.l.verma@intel.com,
	dave.jiang@intel.com, agk@redhat.com, snitzer@redhat.com,
	dm-devel@redhat.com, ira.weiny@intel.com, willy@infradead.org,
	vgoyal@redhat.com, linux-fsdevel@vger.kernel.org,
	nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org,
	linux-xfs@vger.kernel.org
Subject: [PATCH v3 7/7] pmem: fix pmem_do_write() avoid writing to 'np' page
Date: Tue, 11 Jan 2022 11:59:30 -0700	[thread overview]
Message-ID: <20220111185930.2601421-8-jane.chu@oracle.com> (raw)
In-Reply-To: <20220111185930.2601421-1-jane.chu@oracle.com>

Since poisoned page is marked as not-present, the first of the
two back-to-back write_pmem() calls can only be made when there
is no poison in the range, otherwise kernel Oops.

Signed-off-by: Jane Chu <jane.chu@oracle.com>
---
 drivers/nvdimm/pmem.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index dd2db4905c85..6e395014da5e 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -187,10 +187,15 @@ static blk_status_t pmem_do_write(struct pmem_device *pmem,
 	 * after clear poison.
 	 */
 	flush_dcache_page(page);
-	write_pmem(pmem_addr, page, page_off, len);
-	if (unlikely(bad_pmem)) {
-		rc = pmem_clear_poison(pmem, pmem_off, len);
+	if (!bad_pmem) {
 		write_pmem(pmem_addr, page, page_off, len);
+	} else {
+		rc = pmem_clear_poison(pmem, pmem_off, len);
+		if (rc == BLK_STS_OK)
+			write_pmem(pmem_addr, page, page_off, len);
+		else
+			pr_warn("%s: failed to clear poison\n",
+				__func__);
 	}
 
 	return rc;
-- 
2.18.4

