From: Arun Easi <aeasi@marvell.com>
Date: Tue, 12 Jul 2022 22:20:39 -0700
Subject: scsi: qla2xxx: Fix response queue handler reading stale packets
Patch-mainline: v5.20-rc1
Git-commit: b1f707146923335849fb70237eec27d4d1ae7d62
References: bsc#1201651

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.

Two module parameters are introduced:

  ql2xrspq_follow_inptr:

    When set, on newer adapters that has queue pointer shadowing, look for
    response packets only until response queue in pointer.

    When reset, response packets are read based on a signature pattern
    logic (old way).

  ql2xrspq_follow_inptr_legacy:

    Like ql2xrspq_follow_inptr, but for those adapters where there is no
    queue pointer shadowing.

Link: https://lore.kernel.org/r/20220713052045.10683-5-njavali@marvell.com
Cc: stable@vger.kernel.org
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/qla2xxx/qla_gbl.h |    2 ++
 drivers/scsi/qla2xxx/qla_isr.c |   24 +++++++++++++++++++++++-
 drivers/scsi/qla2xxx/qla_os.c  |    9 +++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

--- a/drivers/scsi/qla2xxx/qla_gbl.h
+++ b/drivers/scsi/qla2xxx/qla_gbl.h
@@ -195,6 +195,8 @@ extern int ql2xsecenable;
 extern int ql2xenforce_iocb_limit;
 extern int ql2xabts_wait_nvme;
 extern u32 ql2xnvme_queues;
+extern int ql2xrspq_follow_inptr;
+extern int ql2xrspq_follow_inptr_legacy;
 
 extern int qla2x00_loop_reset(scsi_qla_host_t *);
 extern void qla2x00_abort_all_cmds(scsi_qla_host_t *, int);
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -3790,6 +3790,8 @@ 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 rsp_in = 0;
+	int follow_inptr, is_shadow_hba;
 
 	if (!ha->flags.fw_started)
 		return;
@@ -3799,7 +3801,25 @@ 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(_update, _is_shadow_hba, _rsp, _rsp_in)		\
+	do {								\
+		if (_update) {						\
+			_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);
+	follow_inptr = is_shadow_hba ? ql2xrspq_follow_inptr :
+				ql2xrspq_follow_inptr_legacy;
+
+	__update_rsp_in(follow_inptr, is_shadow_hba, rsp, rsp_in);
+
+	while ((likely(follow_inptr &&
+		       rsp->ring_index != rsp_in &&
+		       rsp->ring_ptr->signature != RESPONSE_PROCESSED)) ||
+		       (!follow_inptr &&
+			rsp->ring_ptr->signature != RESPONSE_PROCESSED)) {
 		pkt = (struct sts_entry_24xx *)rsp->ring_ptr;
 
 		rsp->ring_index++;
@@ -3912,6 +3932,8 @@ void qla24xx_process_response_queue(stru
 				}
 				pure_item = qla27xx_copy_fpin_pkt(vha,
 							  (void **)&pkt, &rsp);
+				__update_rsp_in(follow_inptr, is_shadow_hba,
+						rsp, rsp_in);
 				if (!pure_item)
 					break;
 				qla24xx_queue_purex_item(vha, pure_item,
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -339,6 +339,15 @@ module_param(ql2xabts_wait_nvme, int, 04
 MODULE_PARM_DESC(ql2xabts_wait_nvme,
 		 "To wait for ABTS response on I/O timeouts for NVMe. (default: 1)");
 
+int ql2xrspq_follow_inptr = 1;
+module_param(ql2xrspq_follow_inptr, int, 0644);
+MODULE_PARM_DESC(ql2xrspq_follow_inptr,
+		 "Follow RSP IN pointer for RSP updates for HBAs 27xx and newer (default: 1).");
+
+int ql2xrspq_follow_inptr_legacy = 1;
+module_param(ql2xrspq_follow_inptr_legacy, int, 0644);
+MODULE_PARM_DESC(ql2xrspq_follow_inptr_legacy,
+		 "Follow RSP IN pointer for RSP updates for HBAs older than 27XX. (default: 1).");
 
 u32 ql2xdelay_before_pci_error_handling = 5;
 module_param(ql2xdelay_before_pci_error_handling, uint, 0644);
