[PATCH 14/36] tty: can327, move overflow test inside can327_ldisc_rx()'s loop

From: Jiri Slaby (SUSE)
Date: Thu Aug 10 2023 - 05:16:24 EST


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@xxxxxxxxxx>
Cc: Max Staudt <max@xxxxxxxxx>
Cc: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
Cc: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: linux-can@xxxxxxxxxxxxxxx
---
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