scsi: qedi: Fix race during abort timeouts

If the SCSI cmd completes after qedi_tmf_work calls iscsi_itt_to_task then
the qedi qedi_cmd->task_id could be freed and used for another cmd. If we
then call qedi_iscsi_cleanup_task with that task_id we will be cleaning up
the wrong cmd.

Wait to release the task_id until the last put has been done on the
iscsi_task. Because libiscsi grabs a ref to the task when sending the
abort, we know that for the non-abort timeout case that the task_id we are
referencing is for the cmd that was supposed to be aborted.

A latter commit will fix the case where the abort times out while we are
running qedi_tmf_work.

Link: https://lore.kernel.org/r/20210525181821.7617-21-michael.christie@oracle.com
Reviewed-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
index 80f8d35b5900..5304a028db0a 100644
--- a/drivers/scsi/qedi/qedi_iscsi.c
+++ b/drivers/scsi/qedi/qedi_iscsi.c
@@ -783,7 +783,6 @@ static int qedi_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
 	}
 
 	cmd->conn = conn->dd_data;
-	cmd->scsi_cmd = NULL;
 	return qedi_iscsi_send_generic_request(task);
 }
 
@@ -794,6 +793,10 @@ static int qedi_task_xmit(struct iscsi_task *task)
 	struct qedi_cmd *cmd = task->dd_data;
 	struct scsi_cmnd *sc = task->sc;
 
+	/* Clear now so in cleanup_task we know it didn't make it */
+	cmd->scsi_cmd = NULL;
+	cmd->task_id = U16_MAX;
+
 	if (test_bit(QEDI_IN_SHUTDOWN, &qedi_conn->qedi->flags))
 		return -ENODEV;
 
@@ -1391,13 +1394,24 @@ static umode_t qedi_attr_is_visible(int param_type, int param)
 
 static void qedi_cleanup_task(struct iscsi_task *task)
 {
-	if (!task->sc || task->state == ISCSI_TASK_PENDING) {
+	struct qedi_cmd *cmd;
+
+	if (task->state == ISCSI_TASK_PENDING) {
 		QEDI_INFO(NULL, QEDI_LOG_IO, "Returning ref_cnt=%d\n",
 			  refcount_read(&task->refcount));
 		return;
 	}
 
-	qedi_iscsi_unmap_sg_list(task->dd_data);
+	if (task->sc)
+		qedi_iscsi_unmap_sg_list(task->dd_data);
+
+	cmd = task->dd_data;
+	if (cmd->task_id != U16_MAX)
+		qedi_clear_task_idx(iscsi_host_priv(task->conn->session->host),
+				    cmd->task_id);
+
+	cmd->task_id = U16_MAX;
+	cmd->scsi_cmd = NULL;
 }
 
 struct iscsi_transport qedi_iscsi_transport = {