Hi,

Le mardi 27 janvier 2015 à 03:21 -0800, Yuval Shaia a écrit :
> With this fix Scatter-Gather will be supported also in connected mode
> 

Please explain the issue with current kernel and the advantage
of the proposed fix in the commit message. Perhaps benchmarks
against various HCAs would be welcome.

> Signed-off-by: Yuval Shaia <[email protected]>
> ---
>  drivers/infiniband/ulp/ipoib/ipoib.h      |    8 +--
>  drivers/infiniband/ulp/ipoib/ipoib_cm.c   |  107 
> +++++++++++++++++++++++------
>  drivers/infiniband/ulp/ipoib/ipoib_ib.c   |    3 +-
>  drivers/infiniband/ulp/ipoib/ipoib_main.c |    3 +-
>  4 files changed, 91 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h 
> b/drivers/infiniband/ulp/ipoib/ipoib.h
> index d7562be..fb42834 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib.h
> +++ b/drivers/infiniband/ulp/ipoib/ipoib.h
> @@ -170,11 +170,6 @@ struct ipoib_tx_buf {
>       u64             mapping[MAX_SKB_FRAGS + 1];
>  };
>  
> -struct ipoib_cm_tx_buf {
> -     struct sk_buff *skb;
> -     u64             mapping;
> -};
> -
>  struct ib_cm_id;
>  
>  struct ipoib_cm_data {
> @@ -233,7 +228,7 @@ struct ipoib_cm_tx {
>       struct net_device   *dev;
>       struct ipoib_neigh  *neigh;
>       struct ipoib_path   *path;
> -     struct ipoib_cm_tx_buf *tx_ring;
> +     struct ipoib_tx_buf *tx_ring;
>       unsigned             tx_head;
>       unsigned             tx_tail;
>       unsigned long        flags;
> @@ -496,6 +491,7 @@ int ipoib_mcast_stop_thread(struct net_device *dev, int 
> flush);
>  
>  void ipoib_mcast_dev_down(struct net_device *dev);
>  void ipoib_mcast_dev_flush(struct net_device *dev);
> +int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req);
>  
>  #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
>  struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev);
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c 
> b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> index 933efce..056e4d2 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> @@ -88,6 +88,31 @@ static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv 
> *priv, int frags,
>               ib_dma_unmap_page(priv->ca, mapping[i + 1], PAGE_SIZE, 
> DMA_FROM_DEVICE);
>  }
>  
> +static void ipoib_cm_dma_unmap_tx(struct ipoib_dev_priv *priv,
> +                               struct ipoib_tx_buf *tx_req)
> +{
> +     struct sk_buff *skb;
> +     int i, offs;
> +
> +     skb = tx_req->skb;
> +     if (skb_shinfo(skb)->nr_frags) {
> +             offs = 0;
> +             if (skb_headlen(skb)) {
> +                     ib_dma_unmap_single(priv->ca, tx_req->mapping[0],
> +                                         skb_headlen(skb), DMA_TO_DEVICE);
> +                     offs = 1;
> +             }
> +             for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
> +                     const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
> +
> +                     ib_dma_unmap_single(priv->ca, tx_req->mapping[i + offs],
> +                                         skb_frag_size(frag), DMA_TO_DEVICE);
> +             }
> +     } else
> +             ib_dma_unmap_single(priv->ca, tx_req->mapping[0], skb->len,
> +                                 DMA_TO_DEVICE);
> +}
> +
>  static int ipoib_cm_post_receive_srq(struct net_device *dev, int id)
>  {
>       struct ipoib_dev_priv *priv = netdev_priv(dev);
> @@ -707,11 +732,39 @@ static inline int post_send(struct ipoib_dev_priv *priv,
>       return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr);
>  }
>  
> +static inline int post_send_sg(struct ipoib_dev_priv *priv,
> +                            struct ipoib_cm_tx *tx,
> +                            unsigned int wr_id,
> +                            struct sk_buff *skb,
> +                            u64 mapping[MAX_SKB_FRAGS + 1])
> +{
> +     struct ib_send_wr *bad_wr;
> +     int i, off;
> +     skb_frag_t *frags = skb_shinfo(skb)->frags;
> +     int nr_frags = skb_shinfo(skb)->nr_frags;
> +
> +     if (skb_headlen(skb)) {
> +             priv->tx_sge[0].addr = mapping[0];
> +             priv->tx_sge[0].length = skb_headlen(skb);
> +             off = 1;
> +     } else
> +             off = 0;
> +
> +     for (i = 0; i < nr_frags; ++i) {
> +             priv->tx_sge[i + off].addr = mapping[i + off];
> +             priv->tx_sge[i + off].length = frags[i].size;
> +     }
> +     priv->tx_wr.num_sge = nr_frags + off;
> +     priv->tx_wr.wr_id = wr_id | IPOIB_OP_CM;
> +
> +     return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr);
> +}
> +
>  void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct 
> ipoib_cm_tx *tx)
>  {
>       struct ipoib_dev_priv *priv = netdev_priv(dev);
> -     struct ipoib_cm_tx_buf *tx_req;
> -     u64 addr;
> +     struct ipoib_tx_buf *tx_req;
> +     u64 addr = 0;
>       int rc;
>  
>       if (unlikely(skb->len > tx->mtu)) {
> @@ -735,24 +788,37 @@ void ipoib_cm_send(struct net_device *dev, struct 
> sk_buff *skb, struct ipoib_cm_
>        */
>       tx_req = &tx->tx_ring[tx->tx_head & (ipoib_sendq_size - 1)];
>       tx_req->skb = skb;
> -     addr = ib_dma_map_single(priv->ca, skb->data, skb->len, DMA_TO_DEVICE);
> -     if (unlikely(ib_dma_mapping_error(priv->ca, addr))) {
> -             ++dev->stats.tx_errors;
> -             dev_kfree_skb_any(skb);
> -             return;
> -     }
>  
> -     tx_req->mapping = addr;
> +     if (skb_shinfo(skb)->nr_frags) {
> +             if (unlikely(ipoib_dma_map_tx(priv->ca, tx_req))) {
> +                     ++dev->stats.tx_errors;
> +                     dev_kfree_skb_any(skb);
> +                     return;
> +             }
> +             rc = post_send_sg(priv, tx, tx->tx_head &
> +                               (ipoib_sendq_size - 1),
> +                               skb, tx_req->mapping);
> +     } else {
> +             addr = ib_dma_map_single(priv->ca, skb->data, skb->len,
> +                                      DMA_TO_DEVICE);
> +             if (unlikely(ib_dma_mapping_error(priv->ca, addr))) {
> +                     ++dev->stats.tx_errors;
> +                     dev_kfree_skb_any(skb);
> +                     return;
> +             }
> +
> +             tx_req->mapping[0] = addr;
>  
> -     skb_orphan(skb);
> -     skb_dst_drop(skb);
> +             skb_orphan(skb);
> +             skb_dst_drop(skb);
>  
> -     rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1),
> -                    addr, skb->len);
> +             rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1),
> +                            addr, skb->len);
> +     }
>       if (unlikely(rc)) {
>               ipoib_warn(priv, "post_send failed, error %d\n", rc);
>               ++dev->stats.tx_errors;
> -             ib_dma_unmap_single(priv->ca, addr, skb->len, DMA_TO_DEVICE);
> +             ipoib_cm_dma_unmap_tx(priv, tx_req);
>               dev_kfree_skb_any(skb);
>       } else {
>               dev->trans_start = jiffies;
> @@ -777,7 +843,7 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct 
> ib_wc *wc)
>       struct ipoib_dev_priv *priv = netdev_priv(dev);
>       struct ipoib_cm_tx *tx = wc->qp->qp_context;
>       unsigned int wr_id = wc->wr_id & ~IPOIB_OP_CM;
> -     struct ipoib_cm_tx_buf *tx_req;
> +     struct ipoib_tx_buf *tx_req;
>       unsigned long flags;
>  
>       ipoib_dbg_data(priv, "cm send completion: id %d, status: %d\n",
> @@ -791,7 +857,7 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct 
> ib_wc *wc)
>  
>       tx_req = &tx->tx_ring[wr_id];
>  
> -     ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len, 
> DMA_TO_DEVICE);
> +     ipoib_cm_dma_unmap_tx(priv, tx_req);
>  
>       /* FIXME: is this right? Shouldn't we only increment on success? */
>       ++dev->stats.tx_packets;
> @@ -1036,6 +1102,9 @@ static struct ib_qp *ipoib_cm_create_tx_qp(struct 
> net_device *dev, struct ipoib_
>  
>       struct ib_qp *tx_qp;
>  
> +     if (dev->features & NETIF_F_SG)
> +             attr.cap.max_send_sge = MAX_SKB_FRAGS + 1;
> +
>       tx_qp = ib_create_qp(priv->pd, &attr);
>       if (PTR_ERR(tx_qp) == -EINVAL) {
>               ipoib_warn(priv, "can't use GFP_NOIO for QPs on device %s, 
> using GFP_KERNEL\n",
> @@ -1170,7 +1239,7 @@ err_tx:
>  static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
>  {
>       struct ipoib_dev_priv *priv = netdev_priv(p->dev);
> -     struct ipoib_cm_tx_buf *tx_req;
> +     struct ipoib_tx_buf *tx_req;
>       unsigned long begin;
>  
>       ipoib_dbg(priv, "Destroy active connection 0x%x head 0x%x tail 0x%x\n",
> @@ -1197,8 +1266,7 @@ timeout:
>  
>       while ((int) p->tx_tail - (int) p->tx_head < 0) {
>               tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)];
> -             ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len,
> -                                 DMA_TO_DEVICE);
> +             ipoib_cm_dma_unmap_tx(priv, tx_req);
>               dev_kfree_skb_any(tx_req->skb);
>               ++p->tx_tail;
>               netif_tx_lock_bh(p->dev);
> @@ -1455,7 +1523,6 @@ static void ipoib_cm_stale_task(struct work_struct 
> *work)
>       spin_unlock_irq(&priv->lock);
>  }
>  
> -

No need to remove this line.

>  static ssize_t show_mode(struct device *d, struct device_attribute *attr,
>                        char *buf)
>  {
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c 
> b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
> index 72626c3..9e11447 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
> @@ -312,8 +312,7 @@ repost:
>                          "for buf %d\n", wr_id);
>  }
>  
> -static int ipoib_dma_map_tx(struct ib_device *ca,
> -                         struct ipoib_tx_buf *tx_req)
> +int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req)
>  {
>       struct sk_buff *skb = tx_req->skb;
>       u64 *mapping = tx_req->mapping;
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c 
> b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> index 58b5aa3..f9314c6 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> @@ -190,7 +190,7 @@ static netdev_features_t ipoib_fix_features(struct 
> net_device *dev, netdev_featu
>       struct ipoib_dev_priv *priv = netdev_priv(dev);
>  
>       if (test_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags))
> -             features &= ~(NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO);
> +             features &= ~(NETIF_F_IP_CSUM | NETIF_F_TSO);
>  
>       return features;
>  }
> @@ -233,7 +233,6 @@ int ipoib_set_mode(struct net_device *dev, const char 
> *buf)
>                          "will cause multicast packet drops\n");
>               netdev_update_features(dev);
>               rtnl_unlock();
> -             priv->tx_wr.send_flags &= ~IB_SEND_IP_CSUM;

Sure about this removal ? I don't see it related to scatter-gather.

>  
>               ipoib_flush_paths(dev);
>               rtnl_lock();

Regards.

-- 
Yann Droneaud
OPTEYA


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