linux-kernel - [PATCH v0] qed/qed_dev: guard against a possible division by zero

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Date:   Thu,  9 Feb 2023 13:38:13 +0300
From:   Daniil Tatianin <d-tatianin@...dex-team.ru>
To:     Ariel Elior <aelior@...vell.com>
Cc:     Daniil Tatianin <d-tatianin@...dex-team.ru>,
        Manish Chopra <manishc@...vell.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Yuval Mintz <Yuval.Mintz@...gic.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v0] qed/qed_dev: guard against a possible division by zero

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 explicitly checking for
zero when doing the division.

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@...dex-team.ru>
---
 drivers/net/ethernet/qlogic/qed/qed_dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_dev.c b/drivers/net/ethernet/qlogic/qed/qed_dev.c
index d61cd32ec3b6..90927f68c459 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_dev.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dev.c
@@ -5123,7 +5123,7 @@ static int qed_init_wfq_param(struct qed_hwfn *p_hwfn,
 
 	total_left_rate	= min_pf_rate - total_req_min_rate;
 
-	left_rate_per_vp = total_left_rate / non_requested_count;
+	left_rate_per_vp = total_left_rate / (non_requested_count ?: 1);
 	if (left_rate_per_vp <  min_pf_rate / QED_WFQ_UNIT) {
 		DP_VERBOSE(p_hwfn, NETIF_MSG_LINK,
 			   "Non WFQ configured vports rate [%d Mbps] is less than one percent of configured PF min rate[%d Mbps]\n",
-- 
2.25.1