linux-kernel - [PATCH] net: smc911x: Fix min() use in debug code

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Date:   Wed, 18 May 2022 11:04:19 +0200
From:   Geert Uytterhoeven <geert+renesas@...der.be>
To:     "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Guo Zhengkui <guozhengkui@...o.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH] net: smc911x: Fix min() use in debug code

If ENABLE_SMC_DEBUG_PKTS=1:

    drivers/net/ethernet/smsc/smc911x.c: In function ‘smc911x_hardware_send_pkt’:
    include/linux/minmax.h:20:28: error: comparison of distinct pointer types lacks a cast [-Werror]
       20 |  (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
	  |                            ^~
    drivers/net/ethernet/smsc/smc911x.c:483:17: note: in expansion of macro ‘min’
      483 |  PRINT_PKT(buf, min(len, 64));

Fix this by making the constant unsigned, to match the type of "len".
While at it, replace the other missed ternary operator by min(), too.

Convert the dummy PRINT_PKT() from a macro to a static inline function,
to catch mistakes like this without having to enable debug options
manually.

Fixes: 5ff0348b7f755aac ("net: smc911x: replace ternary operator with min()")
Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
---
 drivers/net/ethernet/smsc/smc911x.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smc911x.c b/drivers/net/ethernet/smsc/smc911x.c
index 2694287770e6cd8e..24d66af797d465ca 100644
--- a/drivers/net/ethernet/smsc/smc911x.c
+++ b/drivers/net/ethernet/smsc/smc911x.c
@@ -140,7 +140,7 @@ static void PRINT_PKT(u_char *buf, int length)
 	pr_cont("\n");
 }
 #else
-#define PRINT_PKT(x...)  do { } while (0)
+static inline void PRINT_PKT(u_char *buf, int length) { }
 #endif
 
 
@@ -430,7 +430,7 @@ static inline void	 smc911x_rcv(struct net_device *dev)
 		SMC_PULL_DATA(lp, data, pkt_len+2+3);
 
 		DBG(SMC_DEBUG_PKTS, dev, "Received packet\n");
-		PRINT_PKT(data, ((pkt_len - 4) <= 64) ? pkt_len - 4 : 64);
+		PRINT_PKT(data, min(pkt_len - 4, 64U));
 		skb->protocol = eth_type_trans(skb, dev);
 		netif_rx(skb);
 		dev->stats.rx_packets++;
@@ -480,7 +480,7 @@ static void smc911x_hardware_send_pkt(struct net_device *dev)
 	SMC_SET_TX_FIFO(lp, cmdB);
 
 	DBG(SMC_DEBUG_PKTS, dev, "Transmitted packet\n");
-	PRINT_PKT(buf, min(len, 64));
+	PRINT_PKT(buf, min(len, 64U));
 
 	/* Send pkt via PIO or DMA */
 #ifdef SMC_USE_DMA
-- 
2.25.1