1 files changed, 12 insertions, 5 deletions

diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 309f51336fb9..7221a24e821b 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -327,12 +327,19 @@ struct iscsi_session {
         struct iscsi_transport  *tt;
         struct Scsi_Host        *host;
         struct iscsi_conn       *leadconn;      /* leading connection */
-        spinlock_t              lock;           /* protects session state, *
-                                                 * sequence numbers,       *
+        /* Between the forward and the backward locks exists a strict locking
+         * hierarchy. The mutual exclusion zone protected by the forward lock
+         * can enclose the mutual exclusion zone protected by the backward lock
+         * but not vice versa.
+         */
+        spinlock_t              frwd_lock;      /* protects session state, *
+                                                 * cmdsn, queued_cmdsn     *
                                                  * session resources:      *
-                                                 * - cmdpool,              *
-                                                 * - mgmtpool,             *
-                                                 * - r2tpool               */
+                                                 * - cmdpool kfifo_out ,   *
+                                                 * - mgmtpool,             */
+        spinlock_t              back_lock;      /* protects cmdsn_exp      *
+                                                 * cmdsn_max,              *
+                                                 * cmdpool kfifo_in        */
         int                     state;          /* session state           */
         int                     age;            /* counts session re-opens */