From: Daniil Tatianin <d-tatianin@yandex-team.ru>
Date: Thu, 9 Mar 2023 23:15:56 +0300
Subject: qed/qed_dev: guard against a possible division by zero
Patch-mainline: v6.3-rc3
Git-commit: 1a9dc5610ef89d807acdcfbff93a558f341a44da
References: jsc#SLE-19001

Previously we would divide total_left_rate by zero if num_vports
happened to be 1 because non_requested_count is calculated as
num_vports - req_count. Guard against this by validating num_vports at
the beginning and returning an error otherwise.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.

Fixes: bcd197c81f63 ("qed: Add vport WFQ configuration APIs")
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230309201556.191392-1-d-tatianin@yandex-team.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/qlogic/qed/qed_dev.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/net/ethernet/qlogic/qed/qed_dev.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dev.c
@@ -5080,6 +5080,11 @@ static int qed_init_wfq_param(struct qed
 
 	num_vports = p_hwfn->qm_info.num_vports;
 
+	if (num_vports < 2) {
+		DP_NOTICE(p_hwfn, "Unexpected num_vports: %d\n", num_vports);
+		return -EINVAL;
+	}
+
 	/* Accounting for the vports which are configured for WFQ explicitly */
 	for (i = 0; i < num_vports; i++) {
 		u32 tmp_speed;