target: Remove core TRANSPORT_FREE_CMD_INTR usage

This patch drops TRANSPORT_FREE_CMD_INTR usage from target core, which
includes the removal of transport_generic_free_cmd_intr() symbol,
TRANSPORT_FREE_CMD_INTR usage in transport_processing_thread(), and
special case LUN_RESET handling to skip TRANSPORT_FREE_CMD_INTR processing
in core_tmr_drain_cmd_list(). We now expect that fabric modules will
use an internal workqueue to provide process context when releasing
se_cmd descriptor resources via transport_generic_free_cmd().

Reported-by: Christoph Hellwig <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Roland Dreier <[e-mail]>
Cc: Madhuranath Iyengar <[e-mail]>
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/target/target_core_tmr.c

···
 		 */
 		if (prout_cmd == cmd)
 			continue;
-		/*
-		 * Skip direct processing of TRANSPORT_FREE_CMD_INTR for
-		 * HW target mode fabrics.
-		 */
-		spin_lock(&cmd->t_state_lock);
-		if (cmd->t_state == TRANSPORT_FREE_CMD_INTR) {
-			spin_unlock(&cmd->t_state_lock);
-			continue;
-		}
-		spin_unlock(&cmd->t_state_lock);
 
 		atomic_set(&cmd->t_transport_queue_active, 0);
 		atomic_dec(&qobj->queue_cnt);

drivers/target/target_core_transport.c

···
 }
 EXPORT_SYMBOL(transport_generic_handle_tmr);
 
-void transport_generic_free_cmd_intr(
-	struct se_cmd *cmd)
-{
-	transport_add_cmd_to_queue(cmd, TRANSPORT_FREE_CMD_INTR, false);
-}
-EXPORT_SYMBOL(transport_generic_free_cmd_intr);
-
 /*
  * If the task is active, request it to be stopped and sleep until it
  * has completed.
···
 			break;
 		case TRANSPORT_PROCESS_WRITE:
 			transport_generic_process_write(cmd);
-			break;
-		case TRANSPORT_FREE_CMD_INTR:
-			transport_generic_free_cmd(cmd, 0);
 			break;
 		case TRANSPORT_PROCESS_TMR:
 			transport_generic_do_tmr(cmd);

include/target/target_core_base.h

···
 	TRANSPORT_PROCESS_TMR	= 9,
 	TRANSPORT_ISTATE_PROCESSING = 11,
 	TRANSPORT_NEW_CMD_MAP	= 16,
-	TRANSPORT_FREE_CMD_INTR = 17,
 	TRANSPORT_COMPLETE_QF_WP = 18,
 	TRANSPORT_COMPLETE_QF_OK = 19,
 };

include/target/target_core_transport.h

···
 extern int transport_generic_handle_data(struct se_cmd *);
 extern void transport_new_cmd_failure(struct se_cmd *);
 extern int transport_generic_handle_tmr(struct se_cmd *);
-extern void transport_generic_free_cmd_intr(struct se_cmd *);
 extern bool target_stop_task(struct se_task *task, unsigned long *flags);
 extern int transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *, u32,
 				struct scatterlist *, u32);