| Message ID | 1366235536-15744-6-git-send-email-bigeasy@linutronix.de |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On 4/18/2013 3:22 AM, Sebastian Andrzej Siewior wrote: > In case that we run into OOM during the allocation of the new rx-skb we > don't get one and we have one skb less than we used to have. If this > continues to happen then we end up with no rx-skbs at all. > This patch changes the following: > - if we fail to allocate the new skb, then we treat the currently > completed skb as the new one and so drop the currently received data. > - instead of testing multiple times if the device is gone we rely one > the status field which is set to -ENOSYS in case the channel is going > down and incomplete requests are purged. > cpdma_chan_stop() removes most of the packages with -ENOSYS. The > currently active packet which is removed has the "tear down" bit set. > So if that bit is set, we send ENOSYS as well otherwise we pass the > status bits which are required to figure out which of the two possible > just finished. > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > drivers/net/ethernet/ti/cpsw.c | 33 ++++++++++++------------------- > drivers/net/ethernet/ti/davinci_cpdma.c | 7 ++++++- > 2 files changed, 19 insertions(+), 21 deletions(-) > > diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c > index 559b020..f684e9b 100644 > --- a/drivers/net/ethernet/ti/cpsw.c > +++ b/drivers/net/ethernet/ti/cpsw.c > @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int status) > void cpsw_rx_handler(void *token, int len, int status) > { > struct sk_buff *skb = token; > + struct sk_buff *new_skb; > struct net_device *ndev = skb->dev; > struct cpsw_priv *priv = netdev_priv(ndev); > int ret = 0; > > cpsw_dual_emac_src_port_detect(status, priv, ndev, skb); > > - /* free and bail if we are shutting down */ > - if (unlikely(!netif_running(ndev)) || > - unlikely(!netif_carrier_ok(ndev))) { > + if (unlikely(status < 0)) { > + /* the interface is going down, skbs are purged */ > dev_kfree_skb_any(skb); > return; > } > - if (likely(status >= 0)) { > + > + new_skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max); > + if (new_skb) { > skb_put(skb, len); > cpts_rx_timestamp(priv->cpts, skb); > skb->protocol = eth_type_trans(skb, ndev); > netif_receive_skb(skb); > priv->stats.rx_bytes += len; > priv->stats.rx_packets++; > - skb = NULL; > - } > - > - if (unlikely(!netif_running(ndev))) { > - if (skb) > - dev_kfree_skb_any(skb); > - return; > + } else { > + priv->stats.rx_dropped++; > + new_skb = skb; Why you want to drop a successfully received packet as you memory alloc failed? Let the stack get it processed and there after you can continue with one less rx skb > } > > - if (likely(!skb)) { > - skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max); > - if (WARN_ON(!skb)) > - return; > - > - ret = cpdma_chan_submit(priv->rxch, skb, skb->data, > - skb_tailroom(skb), 0); > - } > - WARN_ON(ret < 0); > + ret = cpdma_chan_submit(priv->rxch, new_skb, new_skb->data, > + skb_tailroom(new_skb), 0); > + if (WARN_ON(ret < 0)) > + dev_kfree_skb_any(new_skb); > } > > static irqreturn_t cpsw_interrupt(int irq, void *dev_id) > diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c > index 3cc20e7..6b0a89f 100644 > --- a/drivers/net/ethernet/ti/davinci_cpdma.c > +++ b/drivers/net/ethernet/ti/davinci_cpdma.c > @@ -776,6 +776,7 @@ static int __cpdma_chan_process(struct cpdma_chan *chan) > struct cpdma_ctlr *ctlr = chan->ctlr; > struct cpdma_desc __iomem *desc; > int status, outlen; > + int cb_status = 0; > struct cpdma_desc_pool *pool = ctlr->pool; > dma_addr_t desc_dma; > unsigned long flags; > @@ -811,8 +812,12 @@ static int __cpdma_chan_process(struct cpdma_chan *chan) > } > > spin_unlock_irqrestore(&chan->lock, flags); > + if (unlikely(status & CPDMA_DESC_TD_COMPLETE)) > + cb_status = -ENOSYS; > + else > + cb_status = status; > > - __cpdma_chan_free(chan, desc, outlen, status); > + __cpdma_chan_free(chan, desc, outlen, cb_status); > return status; > > unlock_ret: Regards Mugunthan V N -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 04/18/2013 01:50 PM, Mugunthan V N wrote: >> diff --git a/drivers/net/ethernet/ti/cpsw.c >> b/drivers/net/ethernet/ti/cpsw.c >> index 559b020..f684e9b 100644 >> --- a/drivers/net/ethernet/ti/cpsw.c >> +++ b/drivers/net/ethernet/ti/cpsw.c >> @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int <snip> >> - if (unlikely(!netif_running(ndev))) { >> - if (skb) >> - dev_kfree_skb_any(skb); >> - return; >> + } else { >> + priv->stats.rx_dropped++; >> + new_skb = skb; > Why you want to drop a successfully received packet as you memory alloc > failed? > Let the stack get it processed and there after you can continue with one > less > rx skb Because, as I wrote, if this continues you end up without rx skbs. However, if you if you are under memory pressure it is possible that other callers in the stack have the same problem. > > Regards > Mugunthan V N Sebastian -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2013-04-18 at 17:20 +0530, Mugunthan V N wrote: > On 4/18/2013 3:22 AM, Sebastian Andrzej Siewior wrote: > > In case that we run into OOM during the allocation of the new rx-skb we > > don't get one and we have one skb less than we used to have. If this > > continues to happen then we end up with no rx-skbs at all. > > This patch changes the following: > > - if we fail to allocate the new skb, then we treat the currently > > completed skb as the new one and so drop the currently received data. > > - instead of testing multiple times if the device is gone we rely one > > the status field which is set to -ENOSYS in case the channel is going > > down and incomplete requests are purged. > > cpdma_chan_stop() removes most of the packages with -ENOSYS. The > > currently active packet which is removed has the "tear down" bit set. > > So if that bit is set, we send ENOSYS as well otherwise we pass the > > status bits which are required to figure out which of the two possible > > just finished. > > > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > > --- > > drivers/net/ethernet/ti/cpsw.c | 33 ++++++++++++------------------- > > drivers/net/ethernet/ti/davinci_cpdma.c | 7 ++++++- > > 2 files changed, 19 insertions(+), 21 deletions(-) > > > > diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c > > index 559b020..f684e9b 100644 > > --- a/drivers/net/ethernet/ti/cpsw.c > > +++ b/drivers/net/ethernet/ti/cpsw.c > > @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int status) > > void cpsw_rx_handler(void *token, int len, int status) > > { > > struct sk_buff *skb = token; > > + struct sk_buff *new_skb; > > struct net_device *ndev = skb->dev; > > struct cpsw_priv *priv = netdev_priv(ndev); > > int ret = 0; > > > > cpsw_dual_emac_src_port_detect(status, priv, ndev, skb); > > > > - /* free and bail if we are shutting down */ > > - if (unlikely(!netif_running(ndev)) || > > - unlikely(!netif_carrier_ok(ndev))) { > > + if (unlikely(status < 0)) { > > + /* the interface is going down, skbs are purged */ > > dev_kfree_skb_any(skb); > > return; > > } > > - if (likely(status >= 0)) { > > + > > + new_skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max); > > + if (new_skb) { > > skb_put(skb, len); > > cpts_rx_timestamp(priv->cpts, skb); > > skb->protocol = eth_type_trans(skb, ndev); > > netif_receive_skb(skb); > > priv->stats.rx_bytes += len; > > priv->stats.rx_packets++; > > - skb = NULL; > > - } > > - > > - if (unlikely(!netif_running(ndev))) { > > - if (skb) > > - dev_kfree_skb_any(skb); > > - return; > > + } else { > > + priv->stats.rx_dropped++; > > + new_skb = skb; > Why you want to drop a successfully received packet as you memory alloc > failed? > Let the stack get it processed and there after you can continue with one > less > rx skb Have you read the changelog at all ? This patch sounds quite correct to me. If you cannot allocate a new skb, then drop the incoming frame, instead of dealing with strange allocation retries later. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 4/18/2013 5:43 PM, Sebastian Andrzej Siewior wrote: > On 04/18/2013 01:50 PM, Mugunthan V N wrote: >>> diff --git a/drivers/net/ethernet/ti/cpsw.c >>> b/drivers/net/ethernet/ti/cpsw.c >>> index 559b020..f684e9b 100644 >>> --- a/drivers/net/ethernet/ti/cpsw.c >>> +++ b/drivers/net/ethernet/ti/cpsw.c >>> @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int > <snip> >>> - if (unlikely(!netif_running(ndev))) { >>> - if (skb) >>> - dev_kfree_skb_any(skb); >>> - return; >>> + } else { >>> + priv->stats.rx_dropped++; >>> + new_skb = skb; >> Why you want to drop a successfully received packet as you memory alloc >> failed? >> Let the stack get it processed and there after you can continue with one >> less >> rx skb > Because, as I wrote, if this continues you end up without rx skbs. > However, if you if you are under memory pressure it is possible that > other callers in the stack have the same problem. > I had gone through some other drivers and found that this patch is valid so add Acked-by: Mugunthan V N <mugunthanvnm@ti.com> Regards Mugunthan V N -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c index 559b020..f684e9b 100644 --- a/drivers/net/ethernet/ti/cpsw.c +++ b/drivers/net/ethernet/ti/cpsw.c @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int status) void cpsw_rx_handler(void *token, int len, int status) { struct sk_buff *skb = token; + struct sk_buff *new_skb; struct net_device *ndev = skb->dev; struct cpsw_priv *priv = netdev_priv(ndev); int ret = 0; cpsw_dual_emac_src_port_detect(status, priv, ndev, skb); - /* free and bail if we are shutting down */ - if (unlikely(!netif_running(ndev)) || - unlikely(!netif_carrier_ok(ndev))) { + if (unlikely(status < 0)) { + /* the interface is going down, skbs are purged */ dev_kfree_skb_any(skb); return; } - if (likely(status >= 0)) { + + new_skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max); + if (new_skb) { skb_put(skb, len); cpts_rx_timestamp(priv->cpts, skb); skb->protocol = eth_type_trans(skb, ndev); netif_receive_skb(skb); priv->stats.rx_bytes += len; priv->stats.rx_packets++; - skb = NULL; - } - - if (unlikely(!netif_running(ndev))) { - if (skb) - dev_kfree_skb_any(skb); - return; + } else { + priv->stats.rx_dropped++; + new_skb = skb; } - if (likely(!skb)) { - skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max); - if (WARN_ON(!skb)) - return; - - ret = cpdma_chan_submit(priv->rxch, skb, skb->data, - skb_tailroom(skb), 0); - } - WARN_ON(ret < 0); + ret = cpdma_chan_submit(priv->rxch, new_skb, new_skb->data, + skb_tailroom(new_skb), 0); + if (WARN_ON(ret < 0)) + dev_kfree_skb_any(new_skb); } static irqreturn_t cpsw_interrupt(int irq, void *dev_id) diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c index 3cc20e7..6b0a89f 100644 --- a/drivers/net/ethernet/ti/davinci_cpdma.c +++ b/drivers/net/ethernet/ti/davinci_cpdma.c @@ -776,6 +776,7 @@ static int __cpdma_chan_process(struct cpdma_chan *chan) struct cpdma_ctlr *ctlr = chan->ctlr; struct cpdma_desc __iomem *desc; int status, outlen; + int cb_status = 0; struct cpdma_desc_pool *pool = ctlr->pool; dma_addr_t desc_dma; unsigned long flags; @@ -811,8 +812,12 @@ static int __cpdma_chan_process(struct cpdma_chan *chan) } spin_unlock_irqrestore(&chan->lock, flags); + if (unlikely(status & CPDMA_DESC_TD_COMPLETE)) + cb_status = -ENOSYS; + else + cb_status = status; - __cpdma_chan_free(chan, desc, outlen, status); + __cpdma_chan_free(chan, desc, outlen, cb_status); return status; unlock_ret:
In case that we run into OOM during the allocation of the new rx-skb we don't get one and we have one skb less than we used to have. If this continues to happen then we end up with no rx-skbs at all. This patch changes the following: - if we fail to allocate the new skb, then we treat the currently completed skb as the new one and so drop the currently received data. - instead of testing multiple times if the device is gone we rely one the status field which is set to -ENOSYS in case the channel is going down and incomplete requests are purged. cpdma_chan_stop() removes most of the packages with -ENOSYS. The currently active packet which is removed has the "tear down" bit set. So if that bit is set, we send ENOSYS as well otherwise we pass the status bits which are required to figure out which of the two possible just finished. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/net/ethernet/ti/cpsw.c | 33 ++++++++++++------------------- drivers/net/ethernet/ti/davinci_cpdma.c | 7 ++++++- 2 files changed, 19 insertions(+), 21 deletions(-)