From: Bart Van Assche <bvanassche@acm.org>
Date: Wed, 17 Apr 2019 14:44:32 -0700
Subject: scsi: qla2xxx: Remove unnecessary locking from the target code
Patch-mainline: v5.2-rc1
Git-commit: 1b1e68d2a940827725dbf666dd3e73ff12434b0c
References: bsc#1082635 bsc#1123034 bsc#1131304 bsc#1127988 bsc#1141340 bsc#1143706

All callbacks from the target core into the qla2xxx driver and also all I/O
completion functions are serialized per command. Since .cmd_sent_to_fw and
.trc_flags are only modified from inside these functions it is not
necessary to protect it with locking. Remove the superfluous locking.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Cc: Giridhar Malavali <gmalavali@marvell.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/qla2xxx/qla_target.c  |    4 ----
 drivers/scsi/qla2xxx/tcm_qla2xxx.c |   10 +---------
 2 files changed, 1 insertion(+), 13 deletions(-)

--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -3392,9 +3392,7 @@ int qlt_xmit_response(struct qla_tgt_cmd
 
 
 	cmd->state = QLA_TGT_STATE_PROCESSED; /* Mid-level is done processing */
-	spin_lock(&cmd->cmd_lock);
 	cmd->cmd_sent_to_fw = 1;
-	spin_unlock(&cmd->cmd_lock);
 	cmd->ctio_flags = le16_to_cpu(pkt->u.status0.flags);
 
 	/* Memory Barrier */
@@ -3475,9 +3473,7 @@ int qlt_rdy_to_xfer(struct qla_tgt_cmd *
 		qlt_load_data_segments(&prm);
 
 	cmd->state = QLA_TGT_STATE_NEED_DATA;
-	spin_lock(&cmd->cmd_lock);
 	cmd->cmd_sent_to_fw = 1;
-	spin_unlock(&cmd->cmd_lock);
 	cmd->ctio_flags = le16_to_cpu(pkt->u.status0.flags);
 
 	/* Memory Barrier */
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -271,17 +271,15 @@ static void tcm_qla2xxx_free_mcmd(struct
 static void tcm_qla2xxx_complete_free(struct work_struct *work)
 {
 	struct qla_tgt_cmd *cmd = container_of(work, struct qla_tgt_cmd, work);
-	unsigned long flags;
 
 	cmd->cmd_in_wq = 0;
 
 	WARN_ON(cmd->trc_flags & TRC_CMD_FREE);
 
-	spin_lock_irqsave(&cmd->cmd_lock, flags);
+	/* To do: protect all tgt_counters manipulations with proper locking. */
 	cmd->qpair->tgt_counters.qla_core_ret_sta_ctio++;
 	cmd->trc_flags |= TRC_CMD_FREE;
 	cmd->cmd_sent_to_fw = 0;
-	spin_unlock_irqrestore(&cmd->cmd_lock, flags);
 
 	transport_generic_free_cmd(&cmd->se_cmd, 0);
 }
@@ -503,24 +501,18 @@ static int tcm_qla2xxx_handle_cmd(scsi_q
 static void tcm_qla2xxx_handle_data_work(struct work_struct *work)
 {
 	struct qla_tgt_cmd *cmd = container_of(work, struct qla_tgt_cmd, work);
-	unsigned long flags;
 
 	/*
 	 * Ensure that the complete FCP WRITE payload has been received.
 	 * Otherwise return an exception via CHECK_CONDITION status.
 	 */
 	cmd->cmd_in_wq = 0;
-
-	spin_lock_irqsave(&cmd->cmd_lock, flags);
 	cmd->cmd_sent_to_fw = 0;
 	if (cmd->aborted) {
-		spin_unlock_irqrestore(&cmd->cmd_lock, flags);
-
 		transport_generic_request_failure(&cmd->se_cmd,
 			TCM_CHECK_CONDITION_ABORT_CMD);
 		return;
 	}
-	spin_unlock_irqrestore(&cmd->cmd_lock, flags);
 
 	cmd->qpair->tgt_counters.qla_core_ret_ctio++;
 	if (!cmd->write_data_transferred) {