From: Bhupesh Sharma <bhsharma@redhat.com>
Date: Mon, 11 May 2020 15:41:42 +0530
Subject: net: qed: Disable SRIOV functionality inside kdump kernel
Patch-mainline: v5.8-rc1
Git-commit: 37d4f8a6b41f622608671ab8434194c819a5e444
References: jsc#SLE-15143

Since we have kdump kernel(s) running under severe memory constraint
it makes sense to disable the qed SRIOV functionality when running the
kdump kernel as kdump configurations on several distributions don't
support SRIOV targets for saving the vmcore (see [1] for example).

Currently the qed SRIOV functionality ends up consuming memory in
the kdump kernel, when we don't really use the same.

An example log seen in the kdump kernel with the SRIOV functionality
enabled can be seen below (obtained via memstrack tool, see [2]):
 dracut-pre-pivot[676]: ======== Report format module_summary: ========
 dracut-pre-pivot[676]: Module qed using 149.6MB (2394 pages), peak allocation 149.6MB (2394 pages)

This patch disables the SRIOV functionality inside kdump kernel and with
the same applied the memory consumption goes down:
 dracut-pre-pivot[671]: ======== Report format module_summary: ========
 dracut-pre-pivot[671]: Module qed using 124.6MB (1993 pages), peak allocation 124.7MB (1995 pages)

[1]. https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_monitoring_and_updating_the_kernel/installing-and-configuring-kdump_managing-monitoring-and-updating-the-kernel#supported-kdump-targets_supported-kdump-configurations-and-targets
[2]. Memstrack tool: https://github.com/ryncsn/memstrack

Cc: kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Ariel Elior <aelior@marvell.com>
Cc: GR-everest-linux-l2@marvell.com
Cc: Manish Chopra <manishc@marvell.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/qlogic/qed/qed_sriov.h  |   10 +++++++---
 drivers/net/ethernet/qlogic/qede/qede_main.c |    2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/qlogic/qed/qed_sriov.h
+++ b/drivers/net/ethernet/qlogic/qed/qed_sriov.h
@@ -32,6 +32,7 @@
 
 #ifndef _QED_SRIOV_H
 #define _QED_SRIOV_H
+#include <linux/crash_dump.h>
 #include <linux/types.h>
 #include "qed_vf.h"
 
@@ -40,9 +41,12 @@
 #define QED_VF_ARRAY_LENGTH (3)
 
 #ifdef CONFIG_QED_SRIOV
-#define IS_VF(cdev)             ((cdev)->b_is_vf)
-#define IS_PF(cdev)             (!((cdev)->b_is_vf))
-#define IS_PF_SRIOV(p_hwfn)     (!!((p_hwfn)->cdev->p_iov_info))
+#define IS_VF(cdev)             (is_kdump_kernel() ? \
+				 (0) : ((cdev)->b_is_vf))
+#define IS_PF(cdev)             (is_kdump_kernel() ? \
+				 (1) : !((cdev)->b_is_vf))
+#define IS_PF_SRIOV(p_hwfn)     (is_kdump_kernel() ? \
+				 (0) : !!((p_hwfn)->cdev->p_iov_info))
 #else
 #define IS_VF(cdev)             (0)
 #define IS_PF(cdev)             (1)
--- a/drivers/net/ethernet/qlogic/qede/qede_main.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
@@ -1214,7 +1214,7 @@ static int qede_probe(struct pci_dev *pd
 	case QEDE_PRIVATE_VF:
 		if (debug & QED_LOG_VERBOSE_MASK)
 			dev_err(&pdev->dev, "Probing a VF\n");
-		is_vf = true;
+		is_vf = is_kdump_kernel() ? false : true;
 		break;
 	default:
 		if (debug & QED_LOG_VERBOSE_MASK)