[PATCH 1/4] scsi: alua: Move a scsi_device_put() call out of alua_check_vpd()

[Bart Van Assche <bvanassche@acm.org>]

This patch fixes the following smatch warning:

drivers/scsi/device_handler/scsi_dh_alua.c:1013 alua_rtpg_queue() warn: sleeping in atomic context

alua_check_vpd() <- disables preempt
-> alua_rtpg_queue()
   -> scsi_device_put()

Cc: Hannes Reinecke <hare@suse.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 23 ++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 610a51538f03..f7bc81cc59ab 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -324,6 +324,7 @@ 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) {
@@ -373,11 +374,14 @@ 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);
 
-	alua_rtpg_queue(rcu_dereference_protected(h->pg,
+	put_sdev = 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);
 
@@ -968,9 +972,10 @@ 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().
+ * That function is responsible for calling @qdata->fn(). If this function
+ * returns true, the caller is responsible for invoking scsi_device_put(@sdev).
  */
-static bool alua_rtpg_queue(struct alua_port_group *pg,
+static bool __must_check alua_rtpg_queue(struct alua_port_group *pg,
 			    struct scsi_device *sdev,
 			    struct alua_queue_data *qdata, bool force)
 {
@@ -1009,8 +1014,6 @@ static bool alua_rtpg_queue(struct alua_port_group *pg,
 		else
 			kref_put(&pg->kref, release_port_group);
 	}
-	if (sdev)
-		scsi_device_put(sdev);
 
 	return true;
 }
@@ -1117,10 +1120,12 @@ static int alua_activate(struct scsi_device *sdev,
 	rcu_read_unlock();
 	mutex_unlock(&h->init_mutex);
 
-	if (alua_rtpg_queue(pg, sdev, qdata, true))
+	if (alua_rtpg_queue(pg, sdev, qdata, true)) {
+		scsi_device_put(sdev);
 		fn = NULL;
-	else
+	} else {
 		err = SCSI_DH_DEV_OFFLINED;
+	}
 	kref_put(&pg->kref, release_port_group);
 out:
 	if (fn)
@@ -1146,7 +1151,9 @@ static void alua_check(struct scsi_device *sdev, bool force)
 		return;
 	}
 	rcu_read_unlock();
-	alua_rtpg_queue(pg, sdev, NULL, force);
+
+	if (alua_rtpg_queue(pg, sdev, NULL, force))
+		scsi_device_put(sdev);
 	kref_put(&pg->kref, release_port_group);
 }