Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756619AbbHZMpG (ORCPT ); Wed, 26 Aug 2015 08:45:06 -0400 Received: from mail-qk0-f172.google.com ([209.85.220.172]:32866 "EHLO mail-qk0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756467AbbHZMpA (ORCPT ); Wed, 26 Aug 2015 08:45:00 -0400 Subject: Re: [PATCH 2/3] serial: 8250_omap: check how many bytes were injected To: Sebastian Andrzej Siewior References: <1439568064-7907-1-git-send-email-bigeasy@linutronix.de> <1439568064-7907-2-git-send-email-bigeasy@linutronix.de> Cc: linux-kernel@vger.kernel.org, nsekhar@ti.com, linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, john.ogness@linutronix.de, Greg Kroah-Hartman From: Peter Hurley Message-ID: <55DDB4C7.5070709@hurleysoftware.com> Date: Wed, 26 Aug 2015 08:44:55 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <1439568064-7907-2-git-send-email-bigeasy@linutronix.de> 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 Content-Length: 2030 Lines: 53 On 08/14/2015 12:01 PM, Sebastian Andrzej Siewior wrote: > The function tty_insert_flip_string() returns an int and as such it > might fail. So the result is that I kindly asked to insert 48 bytes and > the function only insterted 32. > I have no idea what to do with the remaining 16 so I think dropping them > is the only option. I also increase the buf_overrun counter so userpace > has a clue that we lost bytes. No objection to the patch but I'm curious whether this is something you've actually observed and under what circumstances. Regards, Peter Hurley > Cc: Greg Kroah-Hartman > Signed-off-by: Sebastian Andrzej Siewior > --- > drivers/tty/serial/8250/8250_omap.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c > index 2ac63c8bd946..933f7ef2c004 100644 > --- a/drivers/tty/serial/8250/8250_omap.c > +++ b/drivers/tty/serial/8250/8250_omap.c > @@ -738,6 +738,7 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error) > struct dma_tx_state state; > int count; > unsigned long flags; > + int ret; > > dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr, > dma->rx_size, DMA_FROM_DEVICE); > @@ -753,8 +754,10 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error) > > count = dma->rx_size - state.residue; > > - tty_insert_flip_string(tty_port, dma->rx_buf, count); > - p->port.icount.rx += count; > + ret = tty_insert_flip_string(tty_port, dma->rx_buf, count); > + > + p->port.icount.rx += ret; > + p->port.icount.buf_overrun += count - ret; > unlock: > spin_unlock_irqrestore(&priv->rx_dma_lock, flags); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/