IB/ipoib: Scatter-Gather support in connected mode

By default, IPoIB-CM driver uses 64k MTU. Larger MTU gives better
performance.
This MTU plus overhead puts the memory allocation for IP based packets at
32 4k pages (order 5), which have to be contiguous.
When the system memory under pressure, it was observed that allocating 128k
contiguous physical memory is difficult and causes serious errors (such as
system becomes unusable).

This enhancement resolve the issue by removing the physically contiguous
memory requirement using Scatter/Gather feature that exists in Linux stack.

With this fix Scatter-Gather will be supported also in connected mode.

This change reverts some of the change made in commit e112373fd6aa
("IPoIB/cm: Reduce connected mode TX object size").

The ability to use SG in IPoIB CM is possible because the coupling
between NETIF_F_SG and NETIF_F_CSUM was removed in commit
ec5f06156423 ("net: Kill link between CSUM and SG features.")

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Acked-by: Christian Marie <christian@ponies.io>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index bd94b0a6e9e535f8d8b4a9e1fa1428e0696e2947..79859c4d43c9c572f4946a364b87fdc74acf40a3 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -239,7 +239,7 @@ 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;
@@ -504,6 +504,33 @@ int ipoib_mcast_stop_thread(struct net_device *dev);
 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);
+void ipoib_dma_unmap_tx(struct ipoib_dev_priv *priv,
+                       struct ipoib_tx_buf *tx_req);
+
+static inline void ipoib_build_sge(struct ipoib_dev_priv *priv,
+                                  struct ipoib_tx_buf *tx_req)
+{
+       int i, off;
+       struct sk_buff *skb = tx_req->skb;
+       skb_frag_t *frags = skb_shinfo(skb)->frags;
+       int nr_frags = skb_shinfo(skb)->nr_frags;
+       u64 *mapping = tx_req->mapping;
+
+       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 = skb_frag_size(&frags[i]);
+       }
+       priv->tx_wr.num_sge          = nr_frags + off;
+}
+
 #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
 struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev);
 int ipoib_mcast_iter_next(struct ipoib_mcast_iter *iter);

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index cf32a778e7d0ccc0b6225d9c01442f5d2ec4cdb1..ee39be6ccfb0fdd9aa75ad408543e1f0b08ff1d4 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -694,14 +694,12 @@ repost:
 static inline int post_send(struct ipoib_dev_priv *priv,
                            struct ipoib_cm_tx *tx,
                            unsigned int wr_id,
-                           u64 addr, int len)
+                           struct ipoib_tx_buf *tx_req)
 {
        struct ib_send_wr *bad_wr;
 
-       priv->tx_sge[0].addr          = addr;
-       priv->tx_sge[0].length        = len;
+       ipoib_build_sge(priv, tx_req);
 
-       priv->tx_wr.num_sge     = 1;
        priv->tx_wr.wr_id       = wr_id | IPOIB_OP_CM;
 
        return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr);
@@ -710,8 +708,7 @@ static inline int post_send(struct ipoib_dev_priv *priv,
 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;
        int rc;
 
        if (unlikely(skb->len > tx->mtu)) {
@@ -735,24 +732,21 @@ 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))) {
+
+       if (unlikely(ipoib_dma_map_tx(priv->ca, tx_req))) {
                ++dev->stats.tx_errors;
                dev_kfree_skb_any(skb);
                return;
        }
 
-       tx_req->mapping = addr;
-
        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), tx_req);
        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_dma_unmap_tx(priv, tx_req);
                dev_kfree_skb_any(skb);
        } else {
                dev->trans_start = jiffies;
@@ -777,7 +771,7 @@ 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 +785,7 @@ 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_dma_unmap_tx(priv, tx_req);
 
        /* FIXME: is this right? Shouldn't we only increment on success? */
        ++dev->stats.tx_packets;
@@ -1036,6 +1030,9 @@ 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 +1167,7 @@ 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 +1194,7 @@ 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_dma_unmap_tx(priv, tx_req);
                dev_kfree_skb_any(tx_req->skb);
                ++p->tx_tail;
                netif_tx_lock_bh(p->dev);
@@ -1455,7 +1451,6 @@ static void ipoib_cm_stale_task(struct work_struct *work)
        spin_unlock_irq(&priv->lock);
 }
 
-
 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 058150ff5aa133e6053f7895f18078ba69a7dd9c..d266667ca9b82273dd4b7abb4856f69b29f65174 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -263,8 +263,7 @@ 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;
@@ -305,8 +304,8 @@ partial_error:
        return -EIO;
 }
 
-static void ipoib_dma_unmap_tx(struct ib_device *ca,
-                              struct ipoib_tx_buf *tx_req)
+void ipoib_dma_unmap_tx(struct ipoib_dev_priv *priv,
+                       struct ipoib_tx_buf *tx_req)
 {
        struct sk_buff *skb = tx_req->skb;
        u64 *mapping = tx_req->mapping;
@@ -314,7 +313,8 @@ static void ipoib_dma_unmap_tx(struct ib_device *ca,
        int off;
 
        if (skb_headlen(skb)) {
-               ib_dma_unmap_single(ca, mapping[0], skb_headlen(skb), DMA_TO_DEVICE);
+               ib_dma_unmap_single(priv->ca, mapping[0], skb_headlen(skb),
+                                   DMA_TO_DEVICE);
                off = 1;
        } else
                off = 0;
@@ -322,8 +322,8 @@ static void ipoib_dma_unmap_tx(struct ib_device *ca,
        for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
                const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
-               ib_dma_unmap_page(ca, mapping[i + off], skb_frag_size(frag),
-                                 DMA_TO_DEVICE);
+               ib_dma_unmap_page(priv->ca, mapping[i + off],
+                                 skb_frag_size(frag), DMA_TO_DEVICE);
        }
 }
 
@@ -389,7 +389,7 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 
        tx_req = &priv->tx_ring[wr_id];
 
-       ipoib_dma_unmap_tx(priv->ca, tx_req);
+       ipoib_dma_unmap_tx(priv, tx_req);
 
        ++dev->stats.tx_packets;
        dev->stats.tx_bytes += tx_req->skb->len;
@@ -514,24 +514,10 @@ static inline int post_send(struct ipoib_dev_priv *priv,
                            void *head, int hlen)
 {
        struct ib_send_wr *bad_wr;
-       int i, off;
        struct sk_buff *skb = tx_req->skb;
-       skb_frag_t *frags = skb_shinfo(skb)->frags;
-       int nr_frags = skb_shinfo(skb)->nr_frags;
-       u64 *mapping = tx_req->mapping;
 
-       if (skb_headlen(skb)) {
-               priv->tx_sge[0].addr         = mapping[0];
-               priv->tx_sge[0].length       = skb_headlen(skb);
-               off = 1;
-       } else
-               off = 0;
+       ipoib_build_sge(priv, tx_req);
 
-       for (i = 0; i < nr_frags; ++i) {
-               priv->tx_sge[i + off].addr = mapping[i + off];
-               priv->tx_sge[i + off].length = skb_frag_size(&frags[i]);
-       }
-       priv->tx_wr.num_sge          = nr_frags + off;
        priv->tx_wr.wr_id            = wr_id;
        priv->tx_wr.wr.ud.remote_qpn = qpn;
        priv->tx_wr.wr.ud.ah         = address;
@@ -617,7 +603,7 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb,
                ipoib_warn(priv, "post_send failed, error %d\n", rc);
                ++dev->stats.tx_errors;
                --priv->tx_outstanding;
-               ipoib_dma_unmap_tx(priv->ca, tx_req);
+               ipoib_dma_unmap_tx(priv, tx_req);
                dev_kfree_skb_any(skb);
                if (netif_queue_stopped(dev))
                        netif_wake_queue(dev);
@@ -868,7 +854,7 @@ int ipoib_ib_dev_stop(struct net_device *dev)
                        while ((int) priv->tx_tail - (int) priv->tx_head < 0) {
                                tx_req = &priv->tx_ring[priv->tx_tail &
                                                        (ipoib_sendq_size - 1)];
-                               ipoib_dma_unmap_tx(priv->ca, tx_req);
+                               ipoib_dma_unmap_tx(priv, tx_req);
                                dev_kfree_skb_any(tx_req->skb);
                                ++priv->tx_tail;
                                --priv->tx_outstanding;

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index da3e7e7d5e800afcd9811669d9cb7109c20635bb..59604a7e5e3e84f0d556ae09ea235acdb41ab542 100644 (file)
--- 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;
 }