scsi: libiscsi: Fix locking in __iscsi_conn_send_pdu

Jitendra Bhivare · martinkpetersen · commit 4fa507992f0a · 2016-10-17T13:34:44.000-04:00
The code at free_task label in __iscsi_conn_send_pdu can get executed
from blk_timeout_work which takes queue_lock using spin_lock_irq.
back_lock taken with spin_unlock_bh will cause WARN_ON_ONCE.  The code
gets executed either with bottom half or IRQ disabled hence using
spin_lock/spin_unlock for back_lock is safe.

Signed-off-by: Jitendra Bhivare &lt;jitendra.bhivare@broadcom.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.com&gt;
Reviewed-by: Chris Leech &lt;cleech@redhat.com&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
@@ -791,9 +791,9 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 
 free_task:
 	/* regular RX path uses back_lock */
-	spin_lock_bh(&session->back_lock);
+	spin_lock(&session->back_lock);
 	__iscsi_put_task(task);
-	spin_unlock_bh(&session->back_lock);
+	spin_unlock(&session->back_lock);
 	return NULL;
 }
 
