[PATCH 6.0 12/34] scsi: qla2xxx: Fix response queue handler reading stale packets

[Greg Kroah-Hartman]

From: Arun Easi <aeasi@xxxxxxxxxxx>

commit e4f8a29deb3ba30e414dfb6b09e3ae3bf6dbe74a upstream.

On some platforms, the current logic of relying on finding new packet
solely based on signature pattern can lead to driver reading stale
packets. Though this is a bug in those platforms, reduce such exposures by
limiting reading packets until the IN pointer.

Link: https://lore.kernel.org/r/20220826102559.17474-3-njavali@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Signed-off-by: Arun Easi <aeasi@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_isr.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -3763,7 +3763,8 @@ void qla24xx_process_response_queue(stru
 	struct qla_hw_data *ha = vha->hw;
 	struct purex_entry_24xx *purex_entry;
 	struct purex_item *pure_item;
-	u16 cur_ring_index;
+	u16 rsp_in = 0, cur_ring_index;
+	int is_shadow_hba;
 
 	if (!ha->flags.fw_started)
 		return;
@@ -3773,7 +3774,18 @@ void qla24xx_process_response_queue(stru
 		qla_cpu_update(rsp->qpair, smp_processor_id());
 	}
 
-	while (rsp->ring_ptr->signature != RESPONSE_PROCESSED) {
+#define __update_rsp_in(_is_shadow_hba, _rsp, _rsp_in)			\
+	do {								\
+		_rsp_in = _is_shadow_hba ? *(_rsp)->in_ptr :		\
+				rd_reg_dword_relaxed((_rsp)->rsp_q_in);	\
+	} while (0)
+
+	is_shadow_hba = IS_SHADOW_REG_CAPABLE(ha);
+
+	__update_rsp_in(is_shadow_hba, rsp, rsp_in);
+
+	while (rsp->ring_index != rsp_in &&
+		       rsp->ring_ptr->signature != RESPONSE_PROCESSED) {
 		pkt = (struct sts_entry_24xx *)rsp->ring_ptr;
 		cur_ring_index = rsp->ring_index;
 
@@ -3887,6 +3899,7 @@ process_err:
 				}
 				pure_item = qla27xx_copy_fpin_pkt(vha,
 							  (void **)&pkt, &rsp);
+				__update_rsp_in(is_shadow_hba, rsp, rsp_in);
 				if (!pure_item)
 					break;
 				qla24xx_queue_purex_item(vha, pure_item,