From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: [PATCH 2/3] serial: 8250_omap: check how many bytes were injected Date: Wed, 26 Aug 2015 08:44:55 -0400 Message-ID: <55DDB4C7.5070709@hurleysoftware.com> References: <1439568064-7907-1-git-send-email-bigeasy@linutronix.de> <1439568064-7907-2-git-send-email-bigeasy@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1439568064-7907-2-git-send-email-bigeasy@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org To: Sebastian Andrzej Siewior 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 List-Id: linux-omap@vger.kernel.org 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); > >