IPoIB: Handle 4K IB MTU for UD (datagram) mode

This patch enables IPoIB to use 4K UD messages (when the underlying
device and fabrics support a 4K MTU) by using two scatter buffers when
PAGE_SIZE is less than or equal to thhe HCA IB MTU size.  The first
buffer is for IPoIB header + GRH header, and the second buffer is the
IPoIB payload, which is 4K-4.

Signed-off-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 73b2b17..f1f142d 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -56,11 +56,11 @@
 /* constants */
 
 enum {
-       IPOIB_PACKET_SIZE         = 2048,
-       IPOIB_BUF_SIZE            = IPOIB_PACKET_SIZE + IB_GRH_BYTES,
-
        IPOIB_ENCAP_LEN           = 4,
 
+       IPOIB_UD_HEAD_SIZE        = IB_GRH_BYTES + IPOIB_ENCAP_LEN,
+       IPOIB_UD_RX_SG            = 2, /* max buffer needed for 4K mtu */
+
        IPOIB_CM_MTU              = 0x10000 - 0x10, /* padding to align header to 16 */
        IPOIB_CM_BUF_SIZE         = IPOIB_CM_MTU  + IPOIB_ENCAP_LEN,
        IPOIB_CM_HEAD_SIZE        = IPOIB_CM_BUF_SIZE % PAGE_SIZE,
@@ -139,7 +139,7 @@ struct ipoib_mcast {
 
 struct ipoib_rx_buf {
        struct sk_buff *skb;
-       u64             mapping;
+       u64             mapping[IPOIB_UD_RX_SG];
 };
 
 struct ipoib_tx_buf {
@@ -294,6 +294,7 @@ struct ipoib_dev_priv {
 
        unsigned int admin_mtu;
        unsigned int mcast_mtu;
+       unsigned int max_ib_mtu;
 
        struct ipoib_rx_buf *rx_ring;
 
@@ -305,6 +306,9 @@ struct ipoib_dev_priv {
        struct ib_send_wr    tx_wr;
        unsigned             tx_outstanding;
 
+       struct ib_recv_wr    rx_wr;
+       struct ib_sge        rx_sge[IPOIB_UD_RX_SG];
+
        struct ib_wc ibwc[IPOIB_NUM_WC];
 
        struct list_head dead_ahs;
@@ -366,6 +370,14 @@ struct ipoib_neigh {
        struct list_head    list;
 };
 
+#define IPOIB_UD_MTU(ib_mtu)           (ib_mtu - IPOIB_ENCAP_LEN)
+#define IPOIB_UD_BUF_SIZE(ib_mtu)      (ib_mtu + IB_GRH_BYTES)
+
+static inline int ipoib_ud_need_sg(unsigned int ib_mtu)
+{
+       return IPOIB_UD_BUF_SIZE(ib_mtu) > PAGE_SIZE;
+}
+
 /*
  * We stash a pointer to our private neighbour information after our
  * hardware address in neigh->ha.  The ALIGN() expression here makes

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 0205eb7..7cf1fa7 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -89,28 +89,59 @@ void ipoib_free_ah(struct kref *kref)
        spin_unlock_irqrestore(&priv->lock, flags);
 }
 
+static void ipoib_ud_dma_unmap_rx(struct ipoib_dev_priv *priv,
+                                 u64 mapping[IPOIB_UD_RX_SG])
+{
+       if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
+               ib_dma_unmap_single(priv->ca, mapping[0], IPOIB_UD_HEAD_SIZE,
+                                   DMA_FROM_DEVICE);
+               ib_dma_unmap_page(priv->ca, mapping[1], PAGE_SIZE,
+                                 DMA_FROM_DEVICE);
+       } else
+               ib_dma_unmap_single(priv->ca, mapping[0],
+                                   IPOIB_UD_BUF_SIZE(priv->max_ib_mtu),
+                                   DMA_FROM_DEVICE);
+}
+
+static void ipoib_ud_skb_put_frags(struct ipoib_dev_priv *priv,
+                                  struct sk_buff *skb,
+                                  unsigned int length)
+{
+       if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
+               skb_frag_t *frag = &skb_shinfo(skb)->frags[0];
+               unsigned int size;
+               /*
+                * There is only two buffers needed for max_payload = 4K,
+                * first buf size is IPOIB_UD_HEAD_SIZE
+                */
+               skb->tail += IPOIB_UD_HEAD_SIZE;
+               skb->len  += length;
+
+               size = length - IPOIB_UD_HEAD_SIZE;
+
+               frag->size     = size;
+               skb->data_len += size;
+               skb->truesize += size;
+       } else
+               skb_put(skb, length);
+
+}
+
 static int ipoib_ib_post_receive(struct net_device *dev, int id)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
-       struct ib_sge list;
-       struct ib_recv_wr param;
        struct ib_recv_wr *bad_wr;
        int ret;
 
-       list.addr     = priv->rx_ring[id].mapping;
-       list.length   = IPOIB_BUF_SIZE;
-       list.lkey     = priv->mr->lkey;
+       priv->rx_wr.wr_id   = id | IPOIB_OP_RECV;
+       priv->rx_sge[0].addr = priv->rx_ring[id].mapping[0];
+       priv->rx_sge[1].addr = priv->rx_ring[id].mapping[1];
 
-       param.next    = NULL;
-       param.wr_id   = id | IPOIB_OP_RECV;
-       param.sg_list = &list;
-       param.num_sge = 1;
 
-       ret = ib_post_recv(priv->qp, &param, &bad_wr);
+       ret = ib_post_recv(priv->qp, &priv->rx_wr, &bad_wr);
        if (unlikely(ret)) {
                ipoib_warn(priv, "receive failed for buf %d (%d)\n", id, ret);
-               ib_dma_unmap_single(priv->ca, priv->rx_ring[id].mapping,
-                                   IPOIB_BUF_SIZE, DMA_FROM_DEVICE);
+               ipoib_ud_dma_unmap_rx(priv, priv->rx_ring[id].mapping);
                dev_kfree_skb_any(priv->rx_ring[id].skb);
                priv->rx_ring[id].skb = NULL;
        }
@@ -118,15 +149,21 @@ static int ipoib_ib_post_receive(struct net_device *dev, int id)
        return ret;
 }
 
-static int ipoib_alloc_rx_skb(struct net_device *dev, int id)
+static struct sk_buff *ipoib_alloc_rx_skb(struct net_device *dev, int id)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct sk_buff *skb;
-       u64 addr;
+       int buf_size;
+       u64 *mapping;
 
-       skb = dev_alloc_skb(IPOIB_BUF_SIZE + 4);
-       if (!skb)
-               return -ENOMEM;
+       if (ipoib_ud_need_sg(priv->max_ib_mtu))
+               buf_size = IPOIB_UD_HEAD_SIZE;
+       else
+               buf_size = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);
+
+       skb = dev_alloc_skb(buf_size + 4);
+       if (unlikely(!skb))
+               return NULL;
 
        /*
         * IB will leave a 40 byte gap for a GRH and IPoIB adds a 4 byte
@@ -135,17 +172,32 @@ static int ipoib_alloc_rx_skb(struct net_device *dev, int id)
         */
        skb_reserve(skb, 4);
 
-       addr = ib_dma_map_single(priv->ca, skb->data, IPOIB_BUF_SIZE,
-                                DMA_FROM_DEVICE);
-       if (unlikely(ib_dma_mapping_error(priv->ca, addr))) {
-               dev_kfree_skb_any(skb);
-               return -EIO;
+       mapping = priv->rx_ring[id].mapping;
+       mapping[0] = ib_dma_map_single(priv->ca, skb->data, buf_size,
+                                      DMA_FROM_DEVICE);
+       if (unlikely(ib_dma_mapping_error(priv->ca, mapping[0])))
+               goto error;
+
+       if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
+               struct page *page = alloc_page(GFP_ATOMIC);
+               if (!page)
+                       goto partial_error;
+               skb_fill_page_desc(skb, 0, page, 0, PAGE_SIZE);
+               mapping[1] =
+                       ib_dma_map_page(priv->ca, skb_shinfo(skb)->frags[0].page,
+                                       0, PAGE_SIZE, DMA_FROM_DEVICE);
+               if (unlikely(ib_dma_mapping_error(priv->ca, mapping[1])))
+                       goto partial_error;
        }
 
-       priv->rx_ring[id].skb     = skb;
-       priv->rx_ring[id].mapping = addr;
+       priv->rx_ring[id].skb = skb;
+       return skb;
 
-       return 0;
+partial_error:
+       ib_dma_unmap_single(priv->ca, mapping[0], buf_size, DMA_FROM_DEVICE);
+error:
+       dev_kfree_skb_any(skb);
+       return NULL;
 }
 
 static int ipoib_ib_post_receives(struct net_device *dev)
@@ -154,7 +206,7 @@ static int ipoib_ib_post_receives(struct net_device *dev)
        int i;
 
        for (i = 0; i < ipoib_recvq_size; ++i) {
-               if (ipoib_alloc_rx_skb(dev, i)) {
+               if (!ipoib_alloc_rx_skb(dev, i)) {
                        ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
                        return -ENOMEM;
                }
@@ -172,7 +224,7 @@ static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        unsigned int wr_id = wc->wr_id & ~IPOIB_OP_RECV;
        struct sk_buff *skb;
-       u64 addr;
+       u64 mapping[IPOIB_UD_RX_SG];
 
        ipoib_dbg_data(priv, "recv completion: id %d, status: %d\n",
                       wr_id, wc->status);
@@ -184,15 +236,13 @@ static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
        }
 
        skb  = priv->rx_ring[wr_id].skb;
-       addr = priv->rx_ring[wr_id].mapping;
 
        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        ipoib_warn(priv, "failed recv event "
                                   "(status=%d, wrid=%d vend_err %x)\n",
                                   wc->status, wr_id, wc->vendor_err);
-               ib_dma_unmap_single(priv->ca, addr,
-                                   IPOIB_BUF_SIZE, DMA_FROM_DEVICE);
+               ipoib_ud_dma_unmap_rx(priv, priv->rx_ring[wr_id].mapping);
                dev_kfree_skb_any(skb);
                priv->rx_ring[wr_id].skb = NULL;
                return;
@@ -205,11 +255,14 @@ static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
        if (wc->slid == priv->local_lid && wc->src_qp == priv->qp->qp_num)
                goto repost;
 
+       memcpy(mapping, priv->rx_ring[wr_id].mapping,
+              IPOIB_UD_RX_SG * sizeof *mapping);
+
        /*
         * If we can't allocate a new RX buffer, dump
         * this packet and reuse the old buffer.
         */
-       if (unlikely(ipoib_alloc_rx_skb(dev, wr_id))) {
+       if (unlikely(!ipoib_alloc_rx_skb(dev, wr_id))) {
                ++dev->stats.rx_dropped;
                goto repost;
        }
@@ -217,9 +270,9 @@ static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
        ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
                       wc->byte_len, wc->slid);
 
-       ib_dma_unmap_single(priv->ca, addr, IPOIB_BUF_SIZE, DMA_FROM_DEVICE);
+       ipoib_ud_dma_unmap_rx(priv, mapping);
+       ipoib_ud_skb_put_frags(priv, skb, wc->byte_len);
 
-       skb_put(skb, wc->byte_len);
        skb_pull(skb, IB_GRH_BYTES);
 
        skb->protocol = ((struct ipoib_header *) skb->data)->proto;
@@ -733,10 +786,8 @@ int ipoib_ib_dev_stop(struct net_device *dev, int flush)
                                rx_req = &priv->rx_ring[i];
                                if (!rx_req->skb)
                                        continue;
-                               ib_dma_unmap_single(priv->ca,
-                                                   rx_req->mapping,
-                                                   IPOIB_BUF_SIZE,
-                                                   DMA_FROM_DEVICE);
+                               ipoib_ud_dma_unmap_rx(priv,
+                                                     priv->rx_ring[i].mapping);
                                dev_kfree_skb_any(rx_req->skb);
                                rx_req->skb = NULL;
                        }

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index bd07f02..7a4ed9d 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -195,7 +195,7 @@ static int ipoib_change_mtu(struct net_device *dev, int new_mtu)
                return 0;
        }
 
-       if (new_mtu > IPOIB_PACKET_SIZE - IPOIB_ENCAP_LEN)
+       if (new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu))
                return -EINVAL;
 
        priv->admin_mtu = new_mtu;
@@ -971,10 +971,6 @@ static void ipoib_setup(struct net_device *dev)
                                    NETIF_F_LLTX                |
                                    NETIF_F_HIGHDMA);
 
-       /* MTU will be reset when mcast join happens */
-       dev->mtu                 = IPOIB_PACKET_SIZE - IPOIB_ENCAP_LEN;
-       priv->mcast_mtu          = priv->admin_mtu = dev->mtu;
-
        memcpy(dev->broadcast, ipv4_bcast_addr, INFINIBAND_ALEN);
 
        netif_carrier_off(dev);
@@ -1107,6 +1103,7 @@ static struct net_device *ipoib_add_port(const char *format,
 {
        struct ipoib_dev_priv *priv;
        struct ib_device_attr *device_attr;
+       struct ib_port_attr attr;
        int result = -ENOMEM;
 
        priv = ipoib_intf_alloc(format);
@@ -1115,6 +1112,18 @@ static struct net_device *ipoib_add_port(const char *format,
 
        SET_NETDEV_DEV(priv->dev, hca->dma_device);
 
+       if (!ib_query_port(hca, port, &attr))
+               priv->max_ib_mtu = ib_mtu_enum_to_int(attr.max_mtu);
+       else {
+               printk(KERN_WARNING "%s: ib_query_port %d failed\n",
+                      hca->name, port);
+               goto device_init_failed;
+       }
+
+       /* MTU will be reset when mcast join happens */
+       priv->dev->mtu  = IPOIB_UD_MTU(priv->max_ib_mtu);
+       priv->mcast_mtu  = priv->admin_mtu = priv->dev->mtu;
+
        result = ib_query_pkey(hca, port, 0, &priv->pkey);
        if (result) {
                printk(KERN_WARNING "%s: ib_query_pkey port %d failed (ret = %d)\n",

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 31a53c5..d00a2c1 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -567,8 +567,7 @@ void ipoib_mcast_join_task(struct work_struct *work)
                return;
        }
 
-       priv->mcast_mtu = ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu) -
-               IPOIB_ENCAP_LEN;
+       priv->mcast_mtu = IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
 
        if (!ipoib_cm_admin_enabled(dev))
                dev->mtu = min(priv->mcast_mtu, priv->admin_mtu);

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index 8a20e37..07c03f1 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -150,7 +150,7 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
                        .max_send_wr  = ipoib_sendq_size,
                        .max_recv_wr  = ipoib_recvq_size,
                        .max_send_sge = 1,
-                       .max_recv_sge = 1
+                       .max_recv_sge = IPOIB_UD_RX_SG
                },
                .sq_sig_type = IB_SIGNAL_ALL_WR,
                .qp_type     = IB_QPT_UD
@@ -215,6 +215,19 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
        priv->tx_wr.sg_list     = priv->tx_sge;
        priv->tx_wr.send_flags  = IB_SEND_SIGNALED;
 
+       priv->rx_sge[0].lkey = priv->mr->lkey;
+       if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
+               priv->rx_sge[0].length = IPOIB_UD_HEAD_SIZE;
+               priv->rx_sge[1].length = PAGE_SIZE;
+               priv->rx_sge[1].lkey = priv->mr->lkey;
+               priv->rx_wr.num_sge = IPOIB_UD_RX_SG;
+       } else {
+               priv->rx_sge[0].length = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);
+               priv->rx_wr.num_sge = 1;
+       }
+       priv->rx_wr.next = NULL;
+       priv->rx_wr.sg_list = priv->rx_sge;
+
        return 0;
 
 out_free_cq:

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
index 293f5b8..431fdea 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -89,6 +89,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
                goto err;
        }
 
+       priv->max_ib_mtu = ppriv->max_ib_mtu;
        set_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags);
 
        priv->pkey = pkey;