iscsi-target: Remove SCF_SE_LUN_CMD flag abuses

This patch removes a number of SCF_SE_LUN_CMD flag abuses within iscsi-target
code to determine when iscsit_release_cmd() or transport_generic_free_cmd()
should be called while releasing an individual iscsi_cmd descriptor.

In the place of SCF_SE_LUN_CMD checks, this patch converts existing code to
use a new iscsit_free_cmd() that inspects iscsi_cmd->iscsi_opcode types to
determine which of the above functions should be invoked.  It also removes the
now unnecessary special case checking in iscsit_release_commands_from_conn().

(hch: Use iscsit_free_cmd instead of open-coded alternative)
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target.c

@@ -3538,16 +3538,8 @@ int iscsi_target_tx_thread(void *arg)
 				spin_lock_bh(&conn->cmd_lock);
 				list_del(&cmd->i_list);
 				spin_unlock_bh(&conn->cmd_lock);
-				/*
-				 * Determine if a struct se_cmd is assoicated with
-				 * this struct iscsi_cmd.
-				 */
-				if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) &&
-				    !(cmd->tmr_req))
-					iscsit_release_cmd(cmd);
-				else
-					transport_generic_free_cmd(&cmd->se_cmd,
-								1);
+
+				iscsit_free_cmd(cmd);
 				goto get_immediate;
 			case ISTATE_SEND_NOPIN_WANT_RESPONSE:
 				spin_unlock_bh(&cmd->istate_lock);
@@ -3947,30 +3939,13 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
 	 */
 	spin_lock_bh(&conn->cmd_lock);
 	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_list) {
-		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD)) {
-
-			list_del(&cmd->i_list);
-			spin_unlock_bh(&conn->cmd_lock);
-			iscsit_increment_maxcmdsn(cmd, sess);
-			/*
-			 * Special cases for active iSCSI TMR, and
-			 * transport_lookup_cmd_lun() failing from
-			 * iscsit_get_lun_for_cmd() in iscsit_handle_scsi_cmd().
-			 */
-			if (cmd->tmr_req)
-				transport_generic_free_cmd(&cmd->se_cmd, 1);
-			else
-				iscsit_release_cmd(cmd);
 
-			spin_lock_bh(&conn->cmd_lock);
-			continue;
-		}
 		list_del(&cmd->i_list);
 		spin_unlock_bh(&conn->cmd_lock);
 
 		iscsit_increment_maxcmdsn(cmd, sess);
 
-		transport_generic_free_cmd(&cmd->se_cmd, 1);
+		iscsit_free_cmd(cmd);
 
 		spin_lock_bh(&conn->cmd_lock);
 	}

drivers/target/iscsi/iscsi_target_erl2.c

@@ -143,10 +143,7 @@ void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
 			list_del(&cmd->i_list);
 			cmd->conn = NULL;
 			spin_unlock(&cr->conn_recovery_cmd_lock);
-			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-				iscsit_release_cmd(cmd);
-			else
-				transport_generic_free_cmd(&cmd->se_cmd, 1);
+			iscsit_free_cmd(cmd);
 			spin_lock(&cr->conn_recovery_cmd_lock);
 		}
 		spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -168,10 +165,7 @@ void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
 			list_del(&cmd->i_list);
 			cmd->conn = NULL;
 			spin_unlock(&cr->conn_recovery_cmd_lock);
-			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-				iscsit_release_cmd(cmd);
-			else
-				transport_generic_free_cmd(&cmd->se_cmd, 1);
+			iscsit_free_cmd(cmd);
 			spin_lock(&cr->conn_recovery_cmd_lock);
 		}
 		spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -256,10 +250,7 @@ void iscsit_discard_cr_cmds_by_expstatsn(
 		iscsit_remove_cmd_from_connection_recovery(cmd, sess);
 
 		spin_unlock(&cr->conn_recovery_cmd_lock);
-		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-			iscsit_release_cmd(cmd);
-		else
-			transport_generic_free_cmd(&cmd->se_cmd, 1);
+		iscsit_free_cmd(cmd);
 		spin_lock(&cr->conn_recovery_cmd_lock);
 	}
 	spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -313,10 +304,7 @@ int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
 		list_del(&cmd->i_list);
 
 		spin_unlock_bh(&conn->cmd_lock);
-		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-			iscsit_release_cmd(cmd);
-		else
-			transport_generic_free_cmd(&cmd->se_cmd, 1);
+		iscsit_free_cmd(cmd);
 		spin_lock_bh(&conn->cmd_lock);
 	}
 	spin_unlock_bh(&conn->cmd_lock);
@@ -369,11 +357,7 @@ int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
 
 			list_del(&cmd->i_list);
 			spin_unlock_bh(&conn->cmd_lock);
-
-			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-				iscsit_release_cmd(cmd);
-			else
-				transport_generic_free_cmd(&cmd->se_cmd, 1);
+			iscsit_free_cmd(cmd);
 			spin_lock_bh(&conn->cmd_lock);
 			continue;
 		}
@@ -393,11 +377,7 @@ int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
 		     (cmd->cmd_sn >= conn->sess->exp_cmd_sn)) {
 			list_del(&cmd->i_list);
 			spin_unlock_bh(&conn->cmd_lock);
-
-			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
-				iscsit_release_cmd(cmd);
-			else
-				transport_generic_free_cmd(&cmd->se_cmd, 1);
+			iscsit_free_cmd(cmd);
 			spin_lock_bh(&conn->cmd_lock);
 			continue;
 		}
@@ -422,7 +402,6 @@ int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
 
 		iscsit_free_all_datain_reqs(cmd);
 
-		if (cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD)
 		transport_wait_for_tasks(&cmd->se_cmd);
 		/*
 		 * Add the struct iscsi_cmd to the connection recovery cmd list

drivers/target/iscsi/iscsi_target_util.c

@@ -840,6 +840,23 @@ void iscsit_release_cmd(struct iscsi_cmd *cmd)
 	kmem_cache_free(lio_cmd_cache, cmd);
 }
 
+void iscsit_free_cmd(struct iscsi_cmd *cmd)
+{
+	/*
+	 * Determine if a struct se_cmd is assoicated with
+	 * this struct iscsi_cmd.
+	 */
+	switch (cmd->iscsi_opcode) {
+	case ISCSI_OP_SCSI_CMD:
+	case ISCSI_OP_SCSI_TMFUNC:
+		transport_generic_free_cmd(&cmd->se_cmd, 1);
+		break;
+	default:
+		iscsit_release_cmd(cmd);
+		break;
+	}
+}
+
 int iscsit_check_session_usage_count(struct iscsi_session *sess)
 {
 	spin_lock_bh(&sess->session_usage_lock);

drivers/target/iscsi/iscsi_target_util.h

@@ -30,6 +30,7 @@ extern struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_c
 extern void iscsit_remove_cmd_from_tx_queues(struct iscsi_cmd *, struct iscsi_conn *);
 extern void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *);
 extern void iscsit_release_cmd(struct iscsi_cmd *);
+extern void iscsit_free_cmd(struct iscsi_cmd *);
 extern int iscsit_check_session_usage_count(struct iscsi_session *);
 extern void iscsit_dec_session_usage_count(struct iscsi_session *);
 extern void iscsit_inc_session_usage_count(struct iscsi_session *);