scsi: alua: Move a scsi_device_put() call out of alua_rtpg_select_sdev()

Move a scsi_device_put() call from alua_rtpg_select_sdev() to its
callers. Fixes the following smatch complaint:

drivers/scsi/device_handler/scsi_dh_alua.c:853 alua_rtpg_select_sdev() warn: sleeping in atomic context

alua_rtpg_work() <- disables preempt
-> alua_rtpg_select_sdev()
   -> 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>
Link: https://lore.kernel.org/r/20221031224728.2607760-3-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index f7bc81cc59ab56b1186ae30324c1bb262bffb242..693cd827e138416dc59a58d2e7fc7256bc6926b6 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -815,14 +815,19 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
        return SCSI_DH_RETRY;
 }
 
-static bool alua_rtpg_select_sdev(struct alua_port_group *pg)
+/*
+ * The caller must call scsi_device_put() on the returned pointer if it is not
+ * NULL.
+ */
+static struct scsi_device * __must_check
+alua_rtpg_select_sdev(struct alua_port_group *pg)
 {
        struct alua_dh_data *h;
-       struct scsi_device *sdev = NULL;
+       struct scsi_device *sdev = NULL, *prev_sdev;
 
        lockdep_assert_held(&pg->lock);
        if (WARN_ON(!pg->rtpg_sdev))
-               return false;
+               return NULL;
 
        /*
         * RCU protection isn't necessary for dh_list here
@@ -849,22 +854,22 @@ static bool alua_rtpg_select_sdev(struct alua_port_group *pg)
                pr_warn("%s: no device found for rtpg\n",
                        (pg->device_id_len ?
                         (char *)pg->device_id_str : "(nameless PG)"));
-               return false;
+               return NULL;
        }
 
        sdev_printk(KERN_INFO, sdev, "rtpg retry on different device\n");
 
-       scsi_device_put(pg->rtpg_sdev);
+       prev_sdev = pg->rtpg_sdev;
        pg->rtpg_sdev = sdev;
 
-       return true;
+       return prev_sdev;
 }
 
 static void alua_rtpg_work(struct work_struct *work)
 {
        struct alua_port_group *pg =
                container_of(work, struct alua_port_group, rtpg_work.work);
-       struct scsi_device *sdev;
+       struct scsi_device *sdev, *prev_sdev = NULL;
        LIST_HEAD(qdata_list);
        int err = SCSI_DH_OK;
        struct alua_queue_data *qdata, *tmp;
@@ -905,7 +910,7 @@ static void alua_rtpg_work(struct work_struct *work)
 
                /* If RTPG failed on the current device, try using another */
                if (err == SCSI_DH_RES_TEMP_UNAVAIL &&
-                   alua_rtpg_select_sdev(pg))
+                   (prev_sdev = alua_rtpg_select_sdev(pg)))
                        err = SCSI_DH_IMM_RETRY;
 
                if (err == SCSI_DH_RETRY || err == SCSI_DH_IMM_RETRY ||
@@ -917,9 +922,7 @@ static void alua_rtpg_work(struct work_struct *work)
                                pg->interval = ALUA_RTPG_RETRY_DELAY;
                        pg->flags |= ALUA_PG_RUN_RTPG;
                        spin_unlock_irqrestore(&pg->lock, flags);
-                       queue_delayed_work(kaluad_wq, &pg->rtpg_work,
-                                          pg->interval * HZ);
-                       return;
+                       goto queue_rtpg;
                }
                if (err != SCSI_DH_OK)
                        pg->flags &= ~ALUA_PG_RUN_STPG;
@@ -934,9 +937,7 @@ static void alua_rtpg_work(struct work_struct *work)
                        pg->interval = 0;
                        pg->flags &= ~ALUA_PG_RUNNING;
                        spin_unlock_irqrestore(&pg->lock, flags);
-                       queue_delayed_work(kaluad_wq, &pg->rtpg_work,
-                                          pg->interval * HZ);
-                       return;
+                       goto queue_rtpg;
                }
        }
 
@@ -950,6 +951,9 @@ static void alua_rtpg_work(struct work_struct *work)
        pg->rtpg_sdev = NULL;
        spin_unlock_irqrestore(&pg->lock, flags);
 
+       if (prev_sdev)
+               scsi_device_put(prev_sdev);
+
        list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
                list_del(&qdata->entry);
                if (qdata->callback_fn)
@@ -961,6 +965,12 @@ static void alua_rtpg_work(struct work_struct *work)
        spin_unlock_irqrestore(&pg->lock, flags);
        scsi_device_put(sdev);
        kref_put(&pg->kref, release_port_group);
+       return;
+
+queue_rtpg:
+       if (prev_sdev)
+               scsi_device_put(prev_sdev);
+       queue_delayed_work(kaluad_wq, &pg->rtpg_work, pg->interval * HZ);
 }
 
 /**