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| | | Subject | Re: [PATCH v4 01/10] net: eth: altera: tse_start_xmit ignores tx_buffer call response | From | Thor Thayer <> | Date | Thu, 23 Jul 2020 11:32:00 -0500 |
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On 7/8/20 2:23 AM, Ooi, Joyce wrote: > From: Dalon Westergreen <dalon.westergreen@intel.com> > > 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 <dalon.westergreen@intel.com> > Signed-off-by: Joyce Ooi <joyce.ooi@intel.com> > --- > v2: no change > v3: queue is stopped before returning NETDEV_TX_BUSY > v4: no change > --- > drivers/net/ethernet/altera/altera_sgdma.c | 19 ++++++++++++------- > drivers/net/ethernet/altera/altera_tse_main.c | 4 +++- > 2 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/ethernet/altera/altera_sgdma.c b/drivers/net/ethernet/altera/altera_sgdma.c > index db97170da8c7..fe6276c7e4a3 100644 > --- a/drivers/net/ethernet/altera/altera_sgdma.c > +++ b/drivers/net/ethernet/altera/altera_sgdma.c > @@ -4,6 +4,7 @@ > */ > > #include <linux/list.h> > +#include <linux/netdevice.h> > #include "altera_utils.h" > #include "altera_tse.h" > #include "altera_sgdmahw.h" > @@ -159,10 +160,11 @@ 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) > { > @@ -173,8 +175,11 @@ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) > struct sgdma_descrip __iomem *ndesc = &descbase[1]; > > /* wait 'til the tx sgdma is ready for the next transmit request */ > - if (sgdma_txbusy(priv)) > - return 0; > + if (sgdma_txbusy(priv)) { > + if (!netif_queue_stopped(priv->dev)) > + netif_stop_queue(priv->dev); > + return NETDEV_TX_BUSY; > + } > > sgdma_setup_descrip(cdesc, /* current descriptor */ > ndesc, /* next descriptor */ > @@ -191,7 +196,7 @@ 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 907125abef2c..ec2b36e05c3f 100644 > --- a/drivers/net/ethernet/altera/altera_tse_main.c > +++ b/drivers/net/ethernet/altera/altera_tse_main.c > @@ -595,7 +595,9 @@ static netdev_tx_t 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); > > Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>
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