[PATCH 5.15 080/779] scsi: qla2xxx: Zero undefined mailbox IN registers

[Greg Kroah-Hartman]

From: Bikash Hazarika <bhazarika@xxxxxxxxxxx>

commit 6c96a3c7d49593ef15805f5e497601c87695abc9 upstream.

While requesting a new mailbox command, driver does not write any data to
unused registers.  Initialize the unused register value to zero while
requesting a new mailbox command to prevent stale entry access by firmware.

Link: https://lore.kernel.org/r/20220713052045.10683-4-njavali@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Signed-off-by: Bikash Hazarika <bhazarika@xxxxxxxxxxx>
Signed-off-by: Quinn Tran <qutran@xxxxxxxxxxx>
Signed-off-by: Nilesh Javali <njavali@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/scsi/qla2xxx/qla_mbx.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/scsi/qla2xxx/qla_mbx.c
+++ b/drivers/scsi/qla2xxx/qla_mbx.c
@@ -238,6 +238,8 @@ qla2x00_mailbox_command(scsi_qla_host_t
 			ql_dbg(ql_dbg_mbx, vha, 0x1112,
 			    "mbox[%d]<-0x%04x\n", cnt, *iptr);
 			wrt_reg_word(optr, *iptr);
+		} else {
+			wrt_reg_word(optr, 0);
 		}
 
 		mboxes >>= 1;