[PATCH 4.10 32/81] scsi: scsi_dh_alua: Ensure that alua_activate() calls the completion function

Greg Kroah-Hartman
2017-04-06T08:55:20Z

From: Bart Van Assche <bart.vanassche@sandisk.com>

commit 7cb689fe42927281b8d98606ae5450173fcc66a9 upstream.

Callers of scsi_dh_activate(), e.g. dm-mpath, assume that this function
either returns an error code or calls the completion function. Make
alua_activate() call the completion function even if scsi_device_get()
fails.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Tang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/device_handler/scsi_dh_alua.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -113,7 +113,7 @@ struct alua_queue_data {
#define ALUA_POLICY_SWITCH_ALL 1

static void alua_rtpg_work(struct work_struct *work);
-static void 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);
static void alua_check(struct scsi_device *sdev, bool force);
@@ -866,7 +866,13 @@ static void alua_rtpg_work(struct work_s
kref_put(&pg->kref, release_port_group);
}

-static void alua_rtpg_queue(struct alua_port_group *pg,
+/**
+ * alua_rtpg_queue() - cause RTPG to be submitted asynchronously
+ *
+ * Returns true if and only if alua_rtpg_work() will be called asynchronously.
+ * That function is responsible for calling @qdata->fn().
+ */
+static bool alua_rtpg_queue(struct alua_port_group *pg,
struct scsi_device *sdev,
struct alua_queue_data *qdata, bool force)
{
@@ -875,7 +881,7 @@ static void alua_rtpg_queue(struct alua_
struct workqueue_struct *alua_wq = kaluad_wq;

if (!pg || scsi_device_get(sdev))
- return;
+ return false;

spin_lock_irqsave(&pg->lock, flags);
if (qdata) {
@@ -911,6 +917,8 @@ static void alua_rtpg_queue(struct alua_
}
if (sdev)
scsi_device_put(sdev);
+
+ return true;
}

/*
@@ -1011,11 +1019,13 @@ static int alua_activate(struct scsi_dev
mutex_unlock(&h->init_mutex);
goto out;
}
- fn = NULL;
rcu_read_unlock();
mutex_unlock(&h->init_mutex);

- alua_rtpg_queue(pg, sdev, qdata, true);
+ if (alua_rtpg_queue(pg, sdev, qdata, true))
+ fn = NULL;
+ else
+ err = SCSI_DH_DEV_OFFLINED;
kref_put(&pg->kref, release_port_group);
out:
if (fn)