From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Fri, 30 Jun 2017 00:08:13 -0700
Subject: [PATCH] qla2xxx: Fix incorrect tcm_qla2xxx_free_cmd use during TMR ABORT (v2)
Git-commit: 6bcbb3174caa5f1ccc894f8ae077631659d5a629
Patch-Mainline: v4.13-rc5
References: bsc#1077989

This patch drops two incorrect usages of tcm_qla2xxx_free_cmd()
during TMR ABORT within tcm_qla2xxx_handle_data_work() and
tcm_qla2xxx_aborted_task(), which where attempting to dispatch
into workqueue context to do tcm_qla2xxx_complete_free() and
subsequently invoke transport_generic_free_cmd().

This is incorrect because during TMR ABORT target-core will
drop the outstanding se_cmd->cmd_kref references once it has
quiesced the se_cmd via transport_wait_for_tasks(), and in
the case of qla2xxx it should not attempt to do it's own
transport_generic_free_cmd() once the abort has occured.

As reported by Pascal, this was originally manifesting as a
BUG_ON(cmd->cmd_in_wq) in qlt_free_cmd() during TMR ABORT,
with a LIO backend that had sufficently high enough WRITE
latency to trigger a host side TMR ABORT_TASK.

(v2: Drop the qla_tgt_cmd->write_pending_abort_comp changes,
     as they will be addressed in a seperate series)

Reported-by: Pascal de Bruijn <p.debruijn@unilogic.nl>
Tested-by: Pascal de Bruijn <p.debruijn@unilogic.nl>
Cc: Pascal de Bruijn <p.debruijn@unilogic.nl>
Reported-by: Lukasz Engel <lukasz.engel@softax.pl>
Cc: Lukasz Engel <lukasz.engel@softax.pl>
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Cc: Quinn Tran <quinn.tran@cavium.com>
Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/qla2xxx/tcm_qla2xxx.c | 30 ------------------------------
 1 file changed, 30 deletions(-)

diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index b20da0d27ad7..3f82ea1b72dc 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -500,7 +500,6 @@ static int tcm_qla2xxx_handle_cmd(scsi_qla_host_t *vha, struct qla_tgt_cmd *cmd,
 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.
@@ -508,17 +507,6 @@ static void tcm_qla2xxx_handle_data_work(struct work_struct *work)
 	 */
 	cmd->cmd_in_wq = 0;
 
-	spin_lock_irqsave(&cmd->cmd_lock, flags);
-	cmd->data_work = 1;
-	if (cmd->aborted) {
-		cmd->data_work_free = 1;
-		spin_unlock_irqrestore(&cmd->cmd_lock, flags);
-
-		tcm_qla2xxx_free_cmd(cmd);
-		return;
-	}
-	spin_unlock_irqrestore(&cmd->cmd_lock, flags);
-
 	cmd->qpair->tgt_counters.qla_core_ret_ctio++;
 	if (!cmd->write_data_transferred) {
 		/*
@@ -765,31 +753,13 @@ static void tcm_qla2xxx_queue_tm_rsp(struct se_cmd *se_cmd)
 	qlt_xmit_tm_rsp(mcmd);
 }
 
-#define DATA_WORK_NOT_FREE(_cmd) (_cmd->data_work && !_cmd->data_work_free)
 static void tcm_qla2xxx_aborted_task(struct se_cmd *se_cmd)
 {
 	struct qla_tgt_cmd *cmd = container_of(se_cmd,
 				struct qla_tgt_cmd, se_cmd);
-	unsigned long flags;
 
 	if (qlt_abort_cmd(cmd))
 		return;
-
-	spin_lock_irqsave(&cmd->cmd_lock, flags);
-	if ((cmd->state == QLA_TGT_STATE_NEW)||
-	    ((cmd->state == QLA_TGT_STATE_DATA_IN) &&
-		DATA_WORK_NOT_FREE(cmd))) {
-		cmd->data_work_free = 1;
-		spin_unlock_irqrestore(&cmd->cmd_lock, flags);
-		/*
-		 * cmd has not reached fw, Use this trigger to free it.
-		 */
-		tcm_qla2xxx_free_cmd(cmd);
-		return;
-	}
-	spin_unlock_irqrestore(&cmd->cmd_lock, flags);
-	return;
-
 }
 
 static void tcm_qla2xxx_clear_sess_lookup(struct tcm_qla2xxx_lport *,
-- 
2.12.3