[PATCH for-next 05/17] RDMA/rxe: Add rxe_add_frag() to rxe_mr.c

[Bob Pearson <rpearsonhpe@gmail.com>]

Add the subroutine rxe_add_frag() to add a fragment to an skb.

This is in preparation for supporting fragmented skbs.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_loc.h |  2 ++
 drivers/infiniband/sw/rxe/rxe_mr.c  | 34 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index ff803a957ac1..81a611778d44 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -68,6 +68,8 @@ void rxe_mr_init_dma(int access, struct rxe_mr *mr);
 int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 		     int access, struct rxe_mr *mr);
 int rxe_mr_init_fast(int max_pages, struct rxe_mr *mr);
+int rxe_add_frag(struct sk_buff *skb, struct rxe_phys_buf *buf,
+		 int length, int offset);
 int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 		enum rxe_mr_copy_op op);
 int copy_data(struct rxe_pd *pd, int access, struct rxe_dma_info *dma,
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 1cb997caa292..cf39412cac54 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -286,6 +286,40 @@ void *iova_to_vaddr(struct rxe_mr *mr, u64 iova, int length)
 	return addr;
 }
 
+/**
+ * rxe_add_frag() - Add a frag to a nonlinear packet
+ * @skb: The packet buffer
+ * @buf: Kernel buffer info
+ * @length: Length of fragment
+ * @offset: Offset of fragment in buf
+ *
+ * Returns: 0 on success else a negative errno
+ */
+int rxe_add_frag(struct sk_buff *skb, struct rxe_phys_buf *buf,
+		 int length, int offset)
+{
+	int nr_frags = skb_shinfo(skb)->nr_frags;
+	skb_frag_t *frag = &skb_shinfo(skb)->frags[nr_frags];
+
+	if (nr_frags >= MAX_SKB_FRAGS) {
+		pr_debug("%s: nr_frags (%d) >= MAX_SKB_FRAGS\n",
+			__func__, nr_frags);
+		return -EINVAL;
+	}
+
+	frag->bv_len = length;
+	frag->bv_offset = offset;
+	frag->bv_page = virt_to_page(buf->addr);
+	/* because kfree_skb will call put_page() */
+	get_page(frag->bv_page);
+	skb_shinfo(skb)->nr_frags++;
+
+	skb->data_len += length;
+	skb->len += length;
+
+	return 0;
+}
+
 /* copy data from a range (vaddr, vaddr+length-1) to or from
  * a mr object starting at iova.
  */
-- 
2.34.1