From c904375d4b15122c225c1073fd7a56bd541b0ce5 Mon Sep 17 00:00:00 2001 From: Frans Klaver Date: Thu, 6 Nov 2014 21:10:17 +0100 Subject: [PATCH] serial: 8250_core: actually limit char reads to max_count In serial8250_rx_chars(), max_count is set to 256. Due to the post-decrement operator used in the while() condition, the maximum number of iterations actually 257. This is not a problem, but it is mildly surprising if you're debugging. Use pre-decrement instead. Signed-off-by: Frans Klaver Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 30522d6..d0d0c3b 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1501,7 +1501,7 @@ serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr) ignore_char: lsr = serial_in(up, UART_LSR); - } while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0)); + } while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (--max_count > 0)); spin_unlock(&port->lock); tty_flip_buffer_push(&port->state->port); spin_lock(&port->lock); -- 2.7.4