3 files changed, 26 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 0dcbab3203c9..8754b364f229 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -95,6 +95,7 @@ enum {
         IPOIB_MCAST_FLAG_ATTACHED = 3,
 
         MAX_SEND_CQE              = 16,
+        IPOIB_CM_COPYBREAK        = 256,
 };
 
 #define IPOIB_OP_RECV   (1ul << 31)
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 91c959299910..6223fc39af70 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -523,6 +523,7 @@ void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
         u64 mapping[IPOIB_CM_RX_SG];
         int frags;
         int has_srq;
+        struct sk_buff *small_skb;
 
         ipoib_dbg_data(priv, "cm recv completion: id %d, status: %d\n",
                        wr_id, wc->status);
@@ -577,6 +578,23 @@ void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
                 }
         }
 
+        if (wc->byte_len < IPOIB_CM_COPYBREAK) {
+                int dlen = wc->byte_len;
+
+                small_skb = dev_alloc_skb(dlen + 12);
+                if (small_skb) {
+                        skb_reserve(small_skb, 12);
+                        ib_dma_sync_single_for_cpu(priv->ca, rx_ring[wr_id].mapping[0],
+                                                   dlen, DMA_FROM_DEVICE);
+                        skb_copy_from_linear_data(skb, small_skb->data, dlen);
+                        ib_dma_sync_single_for_device(priv->ca, rx_ring[wr_id].mapping[0],
+                                                      dlen, DMA_FROM_DEVICE);
+                        skb_put(small_skb, dlen);
+                        skb = small_skb;
+                        goto copied;
+                }
+        }
+
         frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
                                               (unsigned)IPOIB_CM_HEAD_SIZE)) / PAGE_SIZE;
 
@@ -599,6 +617,7 @@ void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
 
         skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
 
+copied:
         skb->protocol = ((struct ipoib_header *) skb->data)->proto;
         skb_reset_mac_header(skb);
         skb_pull(skb, IPOIB_ENCAP_LEN);
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index f217b1edd0ac..bfe1dbf99207 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1302,6 +1302,12 @@ static int __init ipoib_init_module(void)
         ipoib_max_conn_qp = min(ipoib_max_conn_qp, IPOIB_CM_MAX_CONN_QP);
 #endif
 
+        /*
+         * When copying small received packets, we only copy from the
+         * linear data part of the SKB, so we rely on this condition.
+         */
+        BUILD_BUG_ON(IPOIB_CM_COPYBREAK > IPOIB_CM_HEAD_SIZE);
+
         ret = ipoib_register_debugfs();
         if (ret)
                 return ret;