target: Convert ->transport_wait_for_tasks usage to transport_generic_free_cmd

This patch converts se_cmd->transport_wait_for_tasks(se_cmd, 1) usage to use
transport_generic_free_cmd() directly in target-core and iscsi-target fabric
usage.  The includes:

*) Removal of the optional transport_generic_free_cmd() call from within
   transport_generic_wait_for_tasks()
*) Usage of existing SCF_SUPPORTED_SAM_OPCODE to determine when
   transport_generic_wait_for_tasks() processing may occur instead of
   checking se_cmd->transport_wait_for_tasks()
*) Move transport_generic_wait_for_tasks() call ahead of core_dec_lacl_count()
   and transport_lun_remove_cmd() in transport_generic_free_cmd() to follow
   existing logic for iscsi-target w/ se_cmd->transport_wait_for_tasks(se_cmd, 1)
*) Removal of se_cmd->transport_wait_for_tasks() function pointer
*) Rename transport_generic_wait_for_tasks() -> transport_wait_for_tasks(), and
   add docbook comment.
*) Add EXPORT_SYMBOL for transport_wait_for_tasks()

For the case in iscsi_target_erl2.c:iscsit_prepare_cmds_for_realligance()
where se_cmd->transport_wait_for_tasks(se_cmd, 0) is called, this patch
adds a direct call to transport_wait_for_tasks().

(hch: Fix transport_generic_free_cmd() usage in iscsit_release_commands_from_conn)
(nab: Add patch: Ensure that TMRs hit wait_for_tasks logic during release)

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 17 insertions, 36 deletions

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 354a833..e4b9ba2 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -3940,7 +3940,6 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
 {
 	struct iscsi_cmd *cmd = NULL, *cmd_tmp = NULL;
 	struct iscsi_session *sess = conn->sess;
-	struct se_cmd *se_cmd;
 	/*
 	 * We expect this function to only ever be called from either RX or TX
 	 * thread context via iscsit_close_connection() once the other context
@@ -3953,16 +3952,13 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
 			list_del(&cmd->i_list);
 			spin_unlock_bh(&conn->cmd_lock);
 			iscsit_increment_maxcmdsn(cmd, sess);
-			se_cmd = &cmd->se_cmd;
 			/*
 			 * 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 && se_cmd->transport_wait_for_tasks)
-				se_cmd->transport_wait_for_tasks(se_cmd, 1);
-			else if (cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD)
-				transport_release_cmd(se_cmd);
+			if (cmd->tmr_req)
+				transport_generic_free_cmd(&cmd->se_cmd, 1);
 			else
 				iscsit_release_cmd(cmd);
 
@@ -3973,10 +3969,8 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
 		spin_unlock_bh(&conn->cmd_lock);
 
 		iscsit_increment_maxcmdsn(cmd, sess);
-		se_cmd = &cmd->se_cmd;
 
-		if (se_cmd->transport_wait_for_tasks)
-			se_cmd->transport_wait_for_tasks(se_cmd, 1);
+		transport_generic_free_cmd(&cmd->se_cmd, 1);
 
 		spin_lock_bh(&conn->cmd_lock);
 	}
diff --git a/drivers/target/iscsi/iscsi_target_erl2.c b/drivers/target/iscsi/iscsi_target_erl2.c
index 000356b..c3803b2 100644
--- a/drivers/target/iscsi/iscsi_target_erl2.c
+++ b/drivers/target/iscsi/iscsi_target_erl2.c
@@ -143,12 +143,10 @@ 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) ||
-			    !(cmd->se_cmd.transport_wait_for_tasks))
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 				iscsit_release_cmd(cmd);
 			else
-				cmd->se_cmd.transport_wait_for_tasks(
-						&cmd->se_cmd, 1);
+				transport_generic_free_cmd(&cmd->se_cmd, 1);
 			spin_lock(&cr->conn_recovery_cmd_lock);
 		}
 		spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -170,12 +168,10 @@ 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) ||
-			    !(cmd->se_cmd.transport_wait_for_tasks))
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 				iscsit_release_cmd(cmd);
 			else
-				cmd->se_cmd.transport_wait_for_tasks(
-						&cmd->se_cmd, 1);
+				transport_generic_free_cmd(&cmd->se_cmd, 1);
 			spin_lock(&cr->conn_recovery_cmd_lock);
 		}
 		spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -260,12 +256,10 @@ 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) ||
-		    !(cmd->se_cmd.transport_wait_for_tasks))
+		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 			iscsit_release_cmd(cmd);
 		else
-			cmd->se_cmd.transport_wait_for_tasks(
-					&cmd->se_cmd, 1);
+			transport_generic_free_cmd(&cmd->se_cmd, 1);
 		spin_lock(&cr->conn_recovery_cmd_lock);
 	}
 	spin_unlock(&cr->conn_recovery_cmd_lock);
@@ -319,12 +313,10 @@ 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) ||
-		    !(cmd->se_cmd.transport_wait_for_tasks))
+		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 			iscsit_release_cmd(cmd);
 		else
-			cmd->se_cmd.transport_wait_for_tasks(
-					&cmd->se_cmd, 1);
+			transport_generic_free_cmd(&cmd->se_cmd, 1);
 		spin_lock_bh(&conn->cmd_lock);
 	}
 	spin_unlock_bh(&conn->cmd_lock);
@@ -378,12 +370,10 @@ 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) ||
-			    !(cmd->se_cmd.transport_wait_for_tasks))
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 				iscsit_release_cmd(cmd);
 			else
-				cmd->se_cmd.transport_wait_for_tasks(
-						&cmd->se_cmd, 1);
+				transport_generic_free_cmd(&cmd->se_cmd, 1);
 			spin_lock_bh(&conn->cmd_lock);
 			continue;
 		}
@@ -404,12 +394,10 @@ 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) ||
-			    !(cmd->se_cmd.transport_wait_for_tasks))
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD))
 				iscsit_release_cmd(cmd);
 			else
-				cmd->se_cmd.transport_wait_for_tasks(
-						&cmd->se_cmd, 1);
+				transport_generic_free_cmd(&cmd->se_cmd, 1);
 			spin_lock_bh(&conn->cmd_lock);
 			continue;
 		}
@@ -434,9 +422,8 @@ 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) &&
-		     cmd->se_cmd.transport_wait_for_tasks)
-			cmd->se_cmd.transport_wait_for_tasks(&cmd->se_cmd, 0);
+		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
 		 */