IB/hfi1: Add functions to receive accelerated ipoib packets

Ipoib netdev will share receive contexts with existing VNIC netdev.
To achieve that, a dummy netdev is allocated with hfi1_devdata to
own the receive contexts, and ipoib and VNIC netdevs will be put
on top of it. Each receive context is associated with a single
NAPI object.

This patch adds the functions to receive incoming packets for
accelerated ipoib.

Link: https://lore.kernel.org/r/20200511160631.173205.54184.stgit@awfm-01.aw.intel.com
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Sadanand Warrier <sadanand.warrier@intel.com>
Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/ipoib_rx.c b/drivers/infiniband/hw/hfi1/ipoib_rx.c
new file mode 100644
index 000000000000..2485663032c7
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/ipoib_rx.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * Copyright(c) 2020 Intel Corporation.
+ *
+ */
+
+#include "netdev.h"
+#include "ipoib.h"
+
+#define HFI1_IPOIB_SKB_PAD ((NET_SKB_PAD) + (NET_IP_ALIGN))
+
+static void copy_ipoib_buf(struct sk_buff *skb, void *data, int size)
+{
+	void *dst_data;
+
+	skb_checksum_none_assert(skb);
+	skb->protocol = *((__be16 *)data);
+
+	dst_data = skb_put(skb, size);
+	memcpy(dst_data, data, size);
+	skb->mac_header = HFI1_IPOIB_PSEUDO_LEN;
+	skb_pull(skb, HFI1_IPOIB_ENCAP_LEN);
+}
+
+static struct sk_buff *prepare_frag_skb(struct napi_struct *napi, int size)
+{
+	struct sk_buff *skb;
+	int skb_size = SKB_DATA_ALIGN(size + HFI1_IPOIB_SKB_PAD);
+	void *frag;
+
+	skb_size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	skb_size = SKB_DATA_ALIGN(skb_size);
+	frag = napi_alloc_frag(skb_size);
+
+	if (unlikely(!frag))
+		return napi_alloc_skb(napi, size);
+
+	skb = build_skb(frag, skb_size);
+
+	if (unlikely(!skb)) {
+		skb_free_frag(frag);
+		return NULL;
+	}
+
+	skb_reserve(skb, HFI1_IPOIB_SKB_PAD);
+	return skb;
+}
+
+struct sk_buff *hfi1_ipoib_prepare_skb(struct hfi1_netdev_rxq *rxq,
+				       int size, void *data)
+{
+	struct napi_struct *napi = &rxq->napi;
+	int skb_size = size + HFI1_IPOIB_ENCAP_LEN;
+	struct sk_buff *skb;
+
+	/*
+	 * For smaller(4k + skb overhead) allocations we will go using
+	 * napi cache. Otherwise we will try to use napi frag cache.
+	 */
+	if (size <= SKB_WITH_OVERHEAD(PAGE_SIZE))
+		skb = napi_alloc_skb(napi, skb_size);
+	else
+		skb = prepare_frag_skb(napi, skb_size);
+
+	if (unlikely(!skb))
+		return NULL;
+
+	copy_ipoib_buf(skb, data, size);
+
+	return skb;
+}