[PATCH 1/8] scsi: hisi_sas: Avoid accessing to SSP task for SMP IOs

[John Garry]

From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>

In function hisi_sas_slot_task_free(), it accesses to SSP task for
non-ATA task. But if it is SMP task here, it accesses to wrong structure
though it may not cause any issue.

To avoid it, only access to ssp task when slot->n_elem_dif is not 0
which indicates this is SSP task.

Signed-off-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/scsi/hisi_sas/hisi_sas_main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 11caa4b0d797..fdf5f0f1b60b 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -229,17 +229,18 @@ void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba, struct sas_task *task,
 		task->lldd_task = NULL;
 
 		if (!sas_protocol_ata(task->task_proto)) {
-			struct sas_ssp_task *ssp_task = &task->ssp_task;
-			struct scsi_cmnd *scsi_cmnd = ssp_task->cmd;
-
 			if (slot->n_elem)
 				dma_unmap_sg(dev, task->scatter,
 					     task->num_scatter,
 					     task->data_dir);
-			if (slot->n_elem_dif)
+			if (slot->n_elem_dif) {
+				struct sas_ssp_task *ssp_task = &task->ssp_task;
+				struct scsi_cmnd *scsi_cmnd = ssp_task->cmd;
+
 				dma_unmap_sg(dev, scsi_prot_sglist(scsi_cmnd),
 					     scsi_prot_sg_count(scsi_cmnd),
 					     task->data_dir);
+			}
 		}
 	}
 
-- 
2.26.2