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From:   "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@kernel.org>,
        Max Staudt <max@enpas.org>,
        Wolfgang Grandegger <wg@grandegger.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-can@vger.kernel.org
Subject: [PATCH 14/36] tty: can327, move overflow test inside can327_ldisc_rx()'s loop
Date:   Thu, 10 Aug 2023 11:14:48 +0200
Message-ID: <20230810091510.13006-15-jirislaby@kernel.org>
In-Reply-To: <20230810091510.13006-1-jirislaby@kernel.org>
References: <20230810091510.13006-1-jirislaby@kernel.org>
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The 'count' is going to be unsigned and the 'count >= 0' test would be
always true then. Move the condition to the loop where this is easier to
check.

It looks as is easier to follow after all too.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Max Staudt <max@enpas.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-can@vger.kernel.org
---
 drivers/net/can/can327.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/net/can/can327.c b/drivers/net/can/can327.c
index 05e9c035e8f6..4533dc00f215 100644
--- a/drivers/net/can/can327.c
+++ b/drivers/net/can/can327.c
@@ -901,7 +901,13 @@ static void can327_ldisc_rx(struct tty_struct *tty, const unsigned char *cp,
 	 */
 	first_new_char_idx = elm->rxfill;
 
-	while (count-- && elm->rxfill < CAN327_SIZE_RXBUF) {
+	while (count--) {
+		if (elm->rxfill >= CAN327_SIZE_RXBUF) {
+			netdev_err(elm->dev,
+				   "Receive buffer overflowed. Bad chip or wiring? count = %i",
+				   count);
+			goto uart_failure;
+		}
 		if (fp && *fp++) {
 			netdev_err(elm->dev,
 				   "Error in received character stream. Check your wiring.");
@@ -930,13 +936,6 @@ static void can327_ldisc_rx(struct tty_struct *tty, const unsigned char *cp,
 		cp++;
 	}
 
-	if (count >= 0) {
-		netdev_err(elm->dev,
-			   "Receive buffer overflowed. Bad chip or wiring? count = %i",
-			   count);
-		goto uart_failure;
-	}
-
 	can327_parse_rxbuf(elm, first_new_char_idx);
 	spin_unlock_bh(&elm->lock);
 
-- 
2.41.0