[PATCH 1/2] scsi: alua: Revert "Move a scsi_device_put() call out of alua_check_vpd()"

Bart Van Assche
2022-11-17T18:36:37Z

There is a bug in commit 0b25e17e9018 ("scsi: alua: Move a
scsi_device_put() call out of alua_check_vpd()"): that patch may cause
alua_rtpg_queue() callers to call scsi_device_put() even if that function
should not be called. Revert that commit to prepare for a different
solution.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Wilck <mwilck@suse.com>
Cc: Sachin Sant <sachinp@linux.ibm.com>
Cc: Benjamin Block <bblock@linux.ibm.com>
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Reported-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 23 ++++++++--------------
1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 693cd827e138..bd4ee294f5c7 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -324,7 +324,6 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
struct alua_port_group *pg, *old_pg = NULL;
bool pg_updated = false;
unsigned long flags;
- bool put_sdev;

group_id = scsi_vpd_tpg_id(sdev, &rel_port);
if (group_id < 0) {
@@ -374,14 +373,11 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
list_add_rcu(&h->node, &pg->dh_list);
spin_unlock_irqrestore(&pg->lock, flags);

- put_sdev = alua_rtpg_queue(rcu_dereference_protected(h->pg,
+ alua_rtpg_queue(rcu_dereference_protected(h->pg,
lockdep_is_held(&h->pg_lock)),
sdev, NULL, true);
spin_unlock(&h->pg_lock);

- if (put_sdev)
- scsi_device_put(sdev);
-
if (old_pg)
kref_put(&old_pg->kref, release_port_group);

@@ -982,10 +978,9 @@ static void alua_rtpg_work(struct work_struct *work)
* RTPG already has been scheduled.
*
* Returns true if and only if alua_rtpg_work() will be called asynchronously.
- * That function is responsible for calling @qdata->fn(). If this function
- * returns true, the caller is responsible for invoking scsi_device_put(@sdev).
+ * That function is responsible for calling @qdata->fn().
*/
-static bool __must_check alua_rtpg_queue(struct alua_port_group *pg,
+static bool alua_rtpg_queue(struct alua_port_group *pg,
struct scsi_device *sdev,
struct alua_queue_data *qdata, bool force)
{
@@ -1024,6 +1019,8 @@ static bool __must_check alua_rtpg_queue(struct alua_port_group *pg,
else
kref_put(&pg->kref, release_port_group);
}
+ if (sdev)
+ scsi_device_put(sdev);

return true;
}
@@ -1130,12 +1127,10 @@ static int alua_activate(struct scsi_device *sdev,
rcu_read_unlock();
mutex_unlock(&h->init_mutex);

- if (alua_rtpg_queue(pg, sdev, qdata, true)) {
- scsi_device_put(sdev);
+ if (alua_rtpg_queue(pg, sdev, qdata, true))
fn = NULL;
- } else {
+ else
err = SCSI_DH_DEV_OFFLINED;
- }
kref_put(&pg->kref, release_port_group);
out:
if (fn)
@@ -1161,9 +1156,7 @@ static void alua_check(struct scsi_device *sdev, bool force)
return;
}
rcu_read_unlock();
-
- if (alua_rtpg_queue(pg, sdev, NULL, force))
- scsi_device_put(sdev);
+ alua_rtpg_queue(pg, sdev, NULL, force);
kref_put(&pg->kref, release_port_group);
}