IPoIB converts skb-fragments to sge adding 1 extra sge when offloading is enabled. Current codepath assumes that the max number of sge a device support is at least MAX_SKB_FRAGS+1, there is no interaction with upper layers to limit number of fragments in an skb if a device suports fewer sge. The assumptions also lead to requesting a fixed number ot sge when IPoIB creates queue-pairs with scatter/gather enabled.
A fallback/slowpath is implemented using skb_linearize to handle cases where the conversion would result in more sges than supported. Signed-off-by: Hans Westgaard Ry <[email protected]> Reviewed-by: Håkon Bugge <[email protected]> Reviewed-by: Wei Lin Guay <[email protected]> --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 4 +++- drivers/infiniband/ulp/ipoib/ipoib_ib.c | 9 +++++++++ drivers/infiniband/ulp/ipoib/ipoib_verbs.c | 4 +++- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 917e46e..0a2bd43 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -1031,7 +1031,9 @@ 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; + attr.cap.max_send_sge = min_t(u32, + priv->ca->attrs.max_sge, + MAX_SKB_FRAGS + 1); tx_qp = ib_create_qp(priv->pd, &attr); if (PTR_ERR(tx_qp) == -EINVAL) { diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c index 5ea0c14..b4f2240 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c @@ -541,6 +541,15 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb, int hlen, rc; void *phead; + if (skb_shinfo(skb)->nr_frags >= priv->ca->attrs.max_sge) { + if (skb_linearize(skb) != 0) { + ipoib_warn(priv, "skb could not be linearized\n"); + ++dev->stats.tx_dropped; + ++dev->stats.tx_errors; + dev_kfree_skb_any(skb); + return; + } + } if (skb_is_gso(skb)) { hlen = skb_transport_offset(skb) + tcp_hdrlen(skb); phead = skb->data; diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c index d48c5ba..62f8ec3 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c @@ -206,7 +206,9 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca) init_attr.create_flags |= IB_QP_CREATE_NETIF_QP; if (dev->features & NETIF_F_SG) - init_attr.cap.max_send_sge = MAX_SKB_FRAGS + 1; + init_attr.cap.max_send_sge = min_t(u32, + priv->ca->attrs.max_sge, + MAX_SKB_FRAGS + 1); priv->qp = ib_create_qp(priv->pd, &init_attr); if (IS_ERR(priv->qp)) { -- 2.4.3
