[PATCH v2 2/3] libnvdimm/security: the 'security' attr never show 'overwrite' state

[Jane Chu <jane.chu@oracle.com>]

'security' attribute displays the security state of an nvdimm.
During normal operation, the nvdimm state maybe one of 'disabled',
'unlocked' or 'locked'.  When an admin issues
  # ndctl sanitize-dimm nmem0 --overwrite
the attribute is expected to change to 'overwrite' until the overwrite
operation completes.

But tests on our systems show that 'overwrite' is never shown during
the overwrite operation. i.e.
  # cat /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/nmem0/security
  unlocked
the attribute remain 'unlocked' through out the operation, consequently
"ndctl wait-overwrite nmem0" command doesn't wait at all.

The driver tracks the state in 'nvdimm->sec.flags': when the operation
starts, it adds an overwrite bit to the flags; and when the operation
completes, it removes the bit. Hence security_show() should check the
'overwrite' bit first, in order to indicate the actual state when multiple
bits are set in the flags.

Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/nvdimm/dimm_devs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b7b77e8..5d72026 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -363,14 +363,14 @@ __weak ssize_t security_show(struct device *dev,
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
 
+	if (test_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags))
+		return sprintf(buf, "overwrite\n");
 	if (test_bit(NVDIMM_SECURITY_DISABLED, &nvdimm->sec.flags))
 		return sprintf(buf, "disabled\n");
 	if (test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.flags))
 		return sprintf(buf, "unlocked\n");
 	if (test_bit(NVDIMM_SECURITY_LOCKED, &nvdimm->sec.flags))
 		return sprintf(buf, "locked\n");
-	if (test_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags))
-		return sprintf(buf, "overwrite\n");
 	return -ENOTTY;
 }
 
-- 
1.8.3.1