From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thor Thayer Subject: Re: [PATCH v2 net-next 01/10] net: eth: altera: tse_start_xmit ignores tx_buffer call response Date: Tue, 18 Dec 2018 09:32:54 -0600 Message-ID: References: <20181213175252.21143-1-dalon.westergreen@linux.intel.com> <20181213175252.21143-2-dalon.westergreen@linux.intel.com> Reply-To: thor.thayer@linux.intel.com Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181213175252.21143-2-dalon.westergreen@linux.intel.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org To: dwesterg@gmail.com, netdev@vger.kernel.org, dinguyen@kernel.org, richardcochran@gmail.com, davem@davemloft.net, vbridger@opensource.altera.com, robh+dt@kernel.org, "mark.rutland@arm.commark.rutland"@arm.com, devicetree@vger.kernel.org, hean.loong.ong@intel.com Cc: Dalon Westergreen List-Id: devicetree@vger.kernel.org Hi Dalon, On 12/13/18 11:52 AM, dwesterg@gmail.com wrote: > From: Dalon Westergreen > > The return from tx_buffer call in tse_start_xmit is > inapropriately ignored. tse_buffer calls should return > 0 for success or NETDEV_TX_BUSY. tse_start_xmit should > return not report a successful transmit when the tse_buffer > call returns an error condition. > > In addition to the above, the msgdma and sgdma do not return > the same value on success or failure. The sgdma_tx_buffer > returned 0 on failure and a positive number of transmitted > packets on success. Given that it only ever sends 1 packet, > this made no sense. The msgdma implementation msgdma_tx_buffer > returns 0 on success. > > -> Don't ignore the return from tse_buffer calls > -> Fix sgdma tse_buffer call to return 0 on success > and NETDEV_TX_BUSY on failure. > > Signed-off-by: Dalon Westergreen > --- > drivers/net/ethernet/altera/altera_sgdma.c | 14 ++++++++------ > drivers/net/ethernet/altera/altera_tse_main.c | 4 +++- > 2 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/altera/altera_sgdma.c b/drivers/net/ethernet/altera/altera_sgdma.c > index 88ef67a998b4..eb47b9b820bb 100644 > --- a/drivers/net/ethernet/altera/altera_sgdma.c > +++ b/drivers/net/ethernet/altera/altera_sgdma.c > @@ -15,6 +15,7 @@ > */ > > #include > +#include > #include "altera_utils.h" > #include "altera_tse.h" > #include "altera_sgdmahw.h" > @@ -170,10 +171,11 @@ void sgdma_clear_txirq(struct altera_tse_private *priv) > SGDMA_CTRLREG_CLRINT); > } > > -/* transmits buffer through SGDMA. Returns number of buffers > - * transmitted, 0 if not possible. > - * > - * tx_lock is held by the caller > +/* transmits buffer through SGDMA. > + * original behavior returned the number of transmitted packets (always 1) & > + * returned 0 on error. This differs from the msgdma. the calling function > + * will now actually look at the code, so from now, 0 is good and return > + * NETDEV_TX_BUSY when busy. > */ > int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) > { > @@ -185,7 +187,7 @@ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) > > /* wait 'til the tx sgdma is ready for the next transmit request */ > if (sgdma_txbusy(priv)) > - return 0; > + return NETDEV_TX_BUSY; > > sgdma_setup_descrip(cdesc, /* current descriptor */ > ndesc, /* next descriptor */ > @@ -202,7 +204,7 @@ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) > /* enqueue the request to the pending transmit queue */ > queue_tx(priv, buffer); > > - return 1; > + return 0; > } > > > diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c > index baca8f704a45..dcb330129e23 100644 > --- a/drivers/net/ethernet/altera/altera_tse_main.c > +++ b/drivers/net/ethernet/altera/altera_tse_main.c > @@ -606,7 +606,9 @@ static int tse_start_xmit(struct sk_buff *skb, struct net_device *dev) > buffer->dma_addr = dma_addr; > buffer->len = nopaged_len; > > - priv->dmaops->tx_buffer(priv, buffer); > + ret = priv->dmaops->tx_buffer(priv, buffer); > + if (ret) > + goto out; > > skb_tx_timestamp(skb); > > If the content hasn't changed, you can just include my previous Acked-by under your Signed-off-by in the subsequent versions. For now though, Acked-by: Thor Thayer