[PATCH v4 4/4] scsi: st: Relock the door after a reset

[Laurence Oberman <loberman@redhat.com>]

With auto-lock enabled, st locks the door at the first read or write and
records ST_LOCKED_AUTO.  A device reset clears the drive's medium removal
prevention, but st keeps its state, so it never locks the door again and
the medium can be removed from the drive while it is in use.

Set the lock state to ST_UNLOCKED when a reset is recognized.  The door
is then locked again at the next read or write.

Suggested-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Assisted-by: Claude sashiko
Signed-off-by: Laurence Oberman <loberman@redhat.com>
---
v4: no changes.
v3: new patch (Kai Mäkisara).

 drivers/scsi/st.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index f548197..e089d3a 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -368,6 +368,8 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 	if (ctr != STp->por_ctr) {
 		STp->por_ctr = ctr;
 		STp->pos_unknown = 1; /* ASC => power on / reset */
+		/* The reset allowed medium removal; relock at next access */
+		STp->door_locked = ST_UNLOCKED;
 		st_printk(KERN_WARNING, STp, "Power on/reset recognized.");
 	}
 
@@ -426,6 +428,7 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 	if (cmdstatp->have_sense && scode == UNIT_ATTENTION &&
 		cmdstatp->sense_hdr.asc == 0x29 && !STp->pos_unknown) {
 		STp->pos_unknown = 1; /* ASC => power on / reset */
+		STp->door_locked = ST_UNLOCKED;
 		st_printk(KERN_WARNING, STp, "Power on/reset recognized.");
 	}
 
-- 
2.43.0