From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755361AbZFVQoS (ORCPT ); Mon, 22 Jun 2009 12:44:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752863AbZFVQn7 (ORCPT ); Mon, 22 Jun 2009 12:43:59 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:37480 "EHLO t61.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752427AbZFVQn6 (ORCPT ); Mon, 22 Jun 2009 12:43:58 -0400 From: Alan Cox Subject: [PATCH 04/15] serial: fix off by one errors To: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Date: Mon, 22 Jun 2009 18:41:56 +0100 Message-ID: <20090622174152.25341.62978.stgit@t61.ukuu.org.uk> In-Reply-To: <20090622172929.25341.31151.stgit@t61.ukuu.org.uk> References: <20090622172929.25341.31151.stgit@t61.ukuu.org.uk> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Roel Kluin In zs_console_putchar() occurs: if (zs_transmit_drain(zport, irq)) write_zsdata(zport, ch); However if in zs_transmit_drain() no empty Tx Buffer occurs, limit reaches -1 => true, and the write still occurs. This patch changes postfix to prefix decrements in this and similar functions to prevent similar mistakes in the future. This decreases the iterations with one but the chosen loop count was arbitrary anyway. In sunhv limit reaches -1, not 0, so the test is off by one. Signed-off-by: Roel Kluin Acked-by: David S. Miller Acked-by: Maciej W. Rozycki Signed-off-by: Andrew Morton Signed-off-by: Alan Cox --- drivers/serial/sb1250-duart.c | 6 +++--- drivers/serial/sunhv.c | 2 +- drivers/serial/zs.c | 6 +++--- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/serial/sb1250-duart.c b/drivers/serial/sb1250-duart.c index a4fb343..319e8b8 100644 --- a/drivers/serial/sb1250-duart.c +++ b/drivers/serial/sb1250-duart.c @@ -204,7 +204,7 @@ static int sbd_receive_drain(struct sbd_port *sport) { int loops = 10000; - while (sbd_receive_ready(sport) && loops--) + while (sbd_receive_ready(sport) && --loops) read_sbdchn(sport, R_DUART_RX_HOLD); return loops; } @@ -218,7 +218,7 @@ static int __maybe_unused sbd_transmit_drain(struct sbd_port *sport) { int loops = 10000; - while (!sbd_transmit_ready(sport) && loops--) + while (!sbd_transmit_ready(sport) && --loops) udelay(2); return loops; } @@ -232,7 +232,7 @@ static int sbd_line_drain(struct sbd_port *sport) { int loops = 10000; - while (!sbd_transmit_empty(sport) && loops--) + while (!sbd_transmit_empty(sport) && --loops) udelay(2); return loops; } diff --git a/drivers/serial/sunhv.c b/drivers/serial/sunhv.c index a94a2ab..1df5325 100644 --- a/drivers/serial/sunhv.c +++ b/drivers/serial/sunhv.c @@ -461,7 +461,7 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign break; udelay(1); } - if (limit <= 0) + if (limit < 0) break; page_bytes -= written; ra += written; diff --git a/drivers/serial/zs.c b/drivers/serial/zs.c index 9e6a873..d8c2809 100644 --- a/drivers/serial/zs.c +++ b/drivers/serial/zs.c @@ -231,7 +231,7 @@ static int zs_receive_drain(struct zs_port *zport) { int loops = 10000; - while ((read_zsreg(zport, R0) & Rx_CH_AV) && loops--) + while ((read_zsreg(zport, R0) & Rx_CH_AV) && --loops) read_zsdata(zport); return loops; } @@ -241,7 +241,7 @@ static int zs_transmit_drain(struct zs_port *zport, int irq) struct zs_scc *scc = zport->scc; int loops = 10000; - while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && loops--) { + while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && --loops) { zs_spin_unlock_cond_irq(&scc->zlock, irq); udelay(2); zs_spin_lock_cond_irq(&scc->zlock, irq); @@ -254,7 +254,7 @@ static int zs_line_drain(struct zs_port *zport, int irq) struct zs_scc *scc = zport->scc; int loops = 10000; - while (!(read_zsreg(zport, R1) & ALL_SNT) && loops--) { + while (!(read_zsreg(zport, R1) & ALL_SNT) && --loops) { zs_spin_unlock_cond_irq(&scc->zlock, irq); udelay(2); zs_spin_lock_cond_irq(&scc->zlock, irq);