2 files changed, 51 insertions, 9 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index a7c6e70f4ef8..9584cbc082fe 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -179,16 +179,15 @@ EXPORT_SYMBOL_GPL(iscsi_prep_scsi_cmd_pdu);
 
 /**
  * iscsi_complete_command - return command back to scsi-ml
- * @session: iscsi session
  * @ctask: iscsi cmd task
  *
  * Must be called with session lock.
  * This function returns the scsi command to scsi-ml and returns
  * the cmd task to the pool of available cmd tasks.
  */
-static void iscsi_complete_command(struct iscsi_session *session,
-                                   struct iscsi_cmd_task *ctask)
+static void iscsi_complete_command(struct iscsi_cmd_task *ctask)
 {
+        struct iscsi_session *session = ctask->conn->session;
         struct scsi_cmnd *sc = ctask->sc;
 
         ctask->state = ISCSI_TASK_COMPLETED;
@@ -198,6 +197,35 @@ static void iscsi_complete_command(struct iscsi_session *session,
         sc->scsi_done(sc);
 }
 
+static void __iscsi_get_ctask(struct iscsi_cmd_task *ctask)
+{
+        atomic_inc(&ctask->refcount);
+}
+
+static void iscsi_get_ctask(struct iscsi_cmd_task *ctask)
+{
+        spin_lock_bh(&ctask->conn->session->lock);
+        __iscsi_get_ctask(ctask);
+        spin_unlock_bh(&ctask->conn->session->lock);
+}
+
+static void __iscsi_put_ctask(struct iscsi_cmd_task *ctask)
+{
+        struct iscsi_conn *conn = ctask->conn;
+
+        if (atomic_dec_and_test(&ctask->refcount)) {
+                conn->session->tt->cleanup_cmd_task(conn, ctask);
+                iscsi_complete_command(ctask);
+        }
+}
+
+static void iscsi_put_ctask(struct iscsi_cmd_task *ctask)
+{
+        spin_lock_bh(&ctask->conn->session->lock);
+        __iscsi_put_ctask(ctask);
+        spin_unlock_bh(&ctask->conn->session->lock);
+}
+
 /**
  * iscsi_cmd_rsp - SCSI Command Response processing
  * @conn: iscsi connection
@@ -274,7 +302,7 @@ out:
                    (long)sc, sc->result, ctask->itt);
         conn->scsirsp_pdus_cnt++;
 
-        iscsi_complete_command(conn->session, ctask);
+        __iscsi_put_ctask(ctask);
         return rc;
 }
 
@@ -338,7 +366,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                         BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
                         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
                                 conn->scsirsp_pdus_cnt++;
-                                iscsi_complete_command(session, ctask);
+                                __iscsi_put_ctask(ctask);
                         }
                         break;
                 case ISCSI_OP_R2T:
@@ -563,7 +591,9 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
         BUG_ON(conn->ctask && conn->mtask);
 
         if (conn->ctask) {
+                iscsi_get_ctask(conn->ctask);
                 rc = tt->xmit_cmd_task(conn, conn->ctask);
+                iscsi_put_ctask(conn->ctask);
                 if (rc)
                         goto again;
                 /* done with this in-progress ctask */
@@ -604,12 +634,19 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
                                          struct iscsi_cmd_task, running);
                 conn->ctask->state = ISCSI_TASK_RUNNING;
                 list_move_tail(conn->xmitqueue.next, &conn->run_list);
+                __iscsi_get_ctask(conn->ctask);
                 spin_unlock_bh(&conn->session->lock);
 
                 rc = tt->xmit_cmd_task(conn, conn->ctask);
                 if (rc)
                         goto again;
+
                 spin_lock_bh(&conn->session->lock);
+                __iscsi_put_ctask(conn->ctask);
+                if (rc) {
+                        spin_unlock_bh(&conn->session->lock);
+                        goto again;
+                }
         }
         spin_unlock_bh(&conn->session->lock);
         /* done with this ctask */
@@ -659,6 +696,7 @@ enum {
         FAILURE_SESSION_FAILED,
         FAILURE_SESSION_FREED,
         FAILURE_WINDOW_CLOSED,
+        FAILURE_OOM,
         FAILURE_SESSION_TERMINATE,
         FAILURE_SESSION_IN_RECOVERY,
         FAILURE_SESSION_RECOVERY_TIMEOUT,
@@ -717,10 +755,15 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
 
         conn = session->leadconn;
 
-        __kfifo_get(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
+        if (!__kfifo_get(session->cmdpool.queue, (void*)&ctask,
+                         sizeof(void*))) {
+                reason = FAILURE_OOM;
+                goto reject;
+        }
         sc->SCp.phase = session->age;
         sc->SCp.ptr = (char *)ctask;
 
+        atomic_set(&ctask->refcount, 1);
         ctask->state = ISCSI_TASK_PENDING;
         ctask->mtask = NULL;
         ctask->conn = conn;
@@ -1057,13 +1100,11 @@ static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
         sc = ctask->sc;
         if (!sc)
                 return;
-
-        conn->session->tt->cleanup_cmd_task(conn, ctask);
         iscsi_ctask_mtask_cleanup(ctask);
 
         sc->result = err;
         sc->resid = sc->request_bufflen;
-        iscsi_complete_command(conn->session, ctask);
+        __iscsi_put_ctask(ctask);
 }
 
 int iscsi_eh_abort(struct scsi_cmnd *sc)
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 4900650bd081..401192e56e50 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -112,6 +112,7 @@ struct iscsi_cmd_task {
 
         /* state set/tested under session->lock */
         int                     state;
+        atomic_t                refcount;
         struct list_head        running;        /* running cmd list */
         void                    *dd_data;       /* driver/transport data */
 };