linux-kernel - [PATCH net-next] iavf: Avoid a memory allocation in iavf_print_link

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Message-Id: <966968bda15a7128a381b589329184dfea3e0548.1695471387.git.christophe.jaillet@wanadoo.fr>
Date:   Sat, 23 Sep 2023 14:17:05 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org
Subject: [PATCH net-next] iavf: Avoid a memory allocation in iavf_print_link_message()

IAVF_MAX_SPEED_STRLEN is only 13 and 'speed' is allocated and freed within
iavf_print_link_message().

'speed' is only used with some snprintf() and netdev_info() calls.

So there is no real use to kzalloc()/free() it. Use the stack instead.
This saves a memory allocation.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/net/ethernet/intel/iavf/iavf_virtchnl.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
index 8ce6389b5815..980dc69d7fbe 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
@@ -1389,18 +1389,14 @@ void iavf_disable_vlan_insertion_v2(struct iavf_adapter *adapter, u16 tpid)
 static void iavf_print_link_message(struct iavf_adapter *adapter)
 {
 	struct net_device *netdev = adapter->netdev;
+	char speed[IAVF_MAX_SPEED_STRLEN];
 	int link_speed_mbps;
-	char *speed;
 
 	if (!adapter->link_up) {
 		netdev_info(netdev, "NIC Link is Down\n");
 		return;
 	}
 
-	speed = kzalloc(IAVF_MAX_SPEED_STRLEN, GFP_KERNEL);
-	if (!speed)
-		return;
-
 	if (ADV_LINK_SUPPORT(adapter)) {
 		link_speed_mbps = adapter->link_speed_mbps;
 		goto print_link_msg;
@@ -1452,7 +1448,6 @@ static void iavf_print_link_message(struct iavf_adapter *adapter)
 	}
 
 	netdev_info(netdev, "NIC Link is Up Speed is %s Full Duplex\n", speed);
-	kfree(speed);
 }
 
 /**
-- 
2.34.1