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Commit 78a50a5e authored by Hans Westgaard Ry's avatar Hans Westgaard Ry Committed by Doug Ledford
Browse files

IB/ipoib: Add handling for sending of skb with many frags 



IPoIB converts skb-fragments to sge adding 1 extra sge when SG 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
sges. The assumptions also lead to requesting a fixed number of sge
when IPoIB creates queue-pairs with SG 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: default avatarHans Westgaard Ry <hans.westgaard.ry@oracle.com>
Reviewed-by: default avatarHåkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: default avatarWei Lin Guay <wei.lin.guay@oracle.com>
Reviewed-by: default avatarYuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent fc77dbd3

drivers/infiniband/ulp/ipoib/ipoib.h

+2 −0
Original line number Diff line number Diff line
@@ -244,6 +244,7 @@ struct ipoib_cm_tx { 
	unsigned	     tx_tail;

	unsigned long	     flags;

	u32		     mtu;

	unsigned             max_send_sge;

};



struct ipoib_cm_rx_buf {
@@ -390,6 +391,7 @@ struct ipoib_dev_priv { 
	int	hca_caps;

	struct ipoib_ethtool_st ethtool;

	struct timer_list poll_timer;

	unsigned max_send_sge;

};



struct ipoib_ah {

drivers/infiniband/ulp/ipoib/ipoib_cm.c

+21 −2
Original line number Diff line number Diff line
@@ -710,6 +710,7 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_ 
	struct ipoib_dev_priv *priv = netdev_priv(dev);

	struct ipoib_tx_buf *tx_req;

	int rc;

	unsigned usable_sge = tx->max_send_sge - !!skb_headlen(skb);



	if (unlikely(skb->len > tx->mtu)) {

		ipoib_warn(priv, "packet len %d (> %d) too long to send, dropping\n",
@@ -719,7 +720,23 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_ 
		ipoib_cm_skb_too_long(dev, skb, tx->mtu - IPOIB_ENCAP_LEN);

		return;

	}



	if (skb_shinfo(skb)->nr_frags > usable_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;

		}

		/* Does skb_linearize return ok without reducing nr_frags? */

		if (skb_shinfo(skb)->nr_frags > usable_sge) {

			ipoib_warn(priv, "too many frags after skb linearize\n");

			++dev->stats.tx_dropped;

			++dev->stats.tx_errors;

			dev_kfree_skb_any(skb);

			return;

		}

	}

	ipoib_dbg_data(priv, "sending packet: head 0x%x length %d connection 0x%x\n",

		       tx->tx_head, skb->len, tx->qp->qp_num);
@@ -1031,7 +1048,8 @@ 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) {
@@ -1040,6 +1058,7 @@ static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_ 
		attr.create_flags &= ~IB_QP_CREATE_USE_GFP_NOIO;

		tx_qp = ib_create_qp(priv->pd, &attr);

	}

	tx->max_send_sge = attr.cap.max_send_sge;

	return tx_qp;

}

drivers/infiniband/ulp/ipoib/ipoib_ib.c

+18 −0
Original line number Diff line number Diff line
@@ -538,6 +538,7 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb, 
	struct ipoib_tx_buf *tx_req;

	int hlen, rc;

	void *phead;

	unsigned usable_sge = priv->max_send_sge - !!skb_headlen(skb);



	if (skb_is_gso(skb)) {

		hlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
@@ -561,6 +562,23 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb, 
		phead = NULL;

		hlen  = 0;

	}

	if (skb_shinfo(skb)->nr_frags > usable_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;

		}

		/* Does skb_linearize return ok without reducing nr_frags? */

		if (skb_shinfo(skb)->nr_frags > usable_sge) {

			ipoib_warn(priv, "too many frags after skb linearize\n");

			++dev->stats.tx_dropped;

			++dev->stats.tx_errors;

			dev_kfree_skb_any(skb);

			return;

		}

	}



	ipoib_dbg_data(priv, "sending packet, length=%d address=%p qpn=0x%06x\n",

		       skb->len, address, qpn);

drivers/infiniband/ulp/ipoib/ipoib_verbs.c

+4 −1
Original line number Diff line number Diff line
@@ -206,7 +206,8 @@ 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)) {
@@ -233,6 +234,8 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca) 
	priv->rx_wr.next = NULL;

	priv->rx_wr.sg_list = priv->rx_sge;



	priv->max_send_sge = init_attr.cap.max_send_sge;



	return 0;



out_free_send_cq: