[PATCH for-next 13/17] RDMA/rxe: Extend rxe_init_req_packet() for frags

[Bob Pearson <rpearsonhpe@xxxxxxxxx>]

Add code to rxe_build_req_packet() to allocate space for the
pad and icrc if the skb is fragmented.

This is in preparation for supporting fragmented skbs.

Signed-off-by: Bob Pearson <rpearsonhpe@xxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_loc.h |  9 +++-
 drivers/infiniband/sw/rxe/rxe_req.c | 74 ++++++++++++++++++++++++-----
 2 files changed, 71 insertions(+), 12 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 12fd5811cd79..cab6acad7a83 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -179,8 +179,15 @@ void rxe_srq_cleanup(struct rxe_pool_elem *elem);
 
 void rxe_dealloc(struct ib_device *ib_dev);
 
-int rxe_completer(void *arg);
+/* rxe_req.c */
+int rxe_prepare_pad_icrc(struct rxe_pkt_info *pkt, struct sk_buff *skb,
+			  int payload, bool frag);
 int rxe_requester(void *arg);
+
+/* rxe_comp.c */
+int rxe_completer(void *arg);
+
+/* rxe_resp.c */
 int rxe_responder(void *arg);
 
 /* rxe_icrc.c */
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index b4bbccc3c008..ea9ab63a2dc1 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -438,27 +438,79 @@ static void rxe_init_roce_hdrs(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 }
 
 static int rxe_init_payload(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
-			    struct rxe_pkt_info *pkt, u32 payload,
-			    struct sk_buff *skb)
+			    struct rxe_pkt_info *pkt, int pad, u32 payload,
+			    struct sk_buff *skb, bool frag)
 {
+	int len = skb_tailroom(skb);
+	int tot_len = payload + pad + RXE_ICRC_SIZE;
+	int access = 0;
 	int skb_offset = 0;
+	int op;
+	void *addr;
 	void *data;
 	int err = 0;
 
 	if (wqe->wr.send_flags & IB_SEND_INLINE) {
+		if (WARN_ON(frag))
+			return -EINVAL;
+		if (len < tot_len)
+			return -EINVAL;
 		data = &wqe->dma.inline_data[wqe->dma.sge_offset];
 		memcpy(payload_addr(pkt), data, payload);
 		wqe->dma.resid -= payload;
 		wqe->dma.sge_offset += payload;
 	} else {
-		err = rxe_copy_dma_data(skb, qp->pd, 0, &wqe->dma,
-					payload_addr(pkt), skb_offset,
-					payload, RXE_COPY_FROM_MR);
+		op = frag ? RXE_FRAG_FROM_MR : RXE_COPY_FROM_MR;
+		addr = frag ? NULL : payload_addr(pkt);
+		err = rxe_copy_dma_data(skb, qp->pd, access, &wqe->dma,
+					addr, skb_offset, payload, op);
 	}
 
 	return err;
 }
 
+/**
+ * rxe_prepare_pad_icrc() - Alloc space if fragmented and init pad and icrc
+ * @pkt: packet info
+ * @skb: packet buffer
+ * @payload: roce payload
+ * @frag: true if skb is fragmented
+ *
+ * Returns: 0 on success else an error
+ */
+int rxe_prepare_pad_icrc(struct rxe_pkt_info *pkt, struct sk_buff *skb,
+			 int payload, bool frag)
+{
+	struct rxe_phys_buf dmabuf;
+	size_t offset;
+	u64 iova;
+	u8 *addr;
+	int err = 0;
+	int pad = (-payload) & 0x3;
+
+	if (frag) {
+		/* allocate bytes at the end of the skb linear buffer
+		 * and build a frag pointing at it
+		 */
+		WARN_ON((skb->end - skb->tail) < 8);
+		addr = skb_end_pointer(skb) - RXE_ICRC_SIZE - pad;
+		iova = (uintptr_t)addr;
+		dmabuf.addr = iova & PAGE_MASK;
+		offset = iova & ~PAGE_MASK;
+		err = rxe_add_frag(skb, &dmabuf, pad + RXE_ICRC_SIZE, offset);
+		if (err)
+			goto err;
+	} else {
+		addr = payload_addr(pkt) + payload;
+	}
+
+	/* init pad and icrc to zero */
+	memset(addr, 0, pad + RXE_ICRC_SIZE);
+
+err:
+	return err;
+}
+
 static struct sk_buff *rxe_init_req_packet(struct rxe_qp *qp,
 					   struct rxe_send_wqe *wqe,
 					   int opcode, u32 payload,
@@ -468,9 +520,9 @@ static struct sk_buff *rxe_init_req_packet(struct rxe_qp *qp,
 	struct sk_buff *skb;
 	struct rxe_av *av;
 	struct rxe_ah *ah;
-	void *padp;
 	int pad;
 	int err = -EINVAL;
+	bool frag = false;
 
 	pkt->rxe = rxe;
 	pkt->opcode = opcode;
@@ -498,15 +550,15 @@ static struct sk_buff *rxe_init_req_packet(struct rxe_qp *qp,
 	rxe_init_roce_hdrs(qp, wqe, pkt, pad);
 
 	if (pkt->mask & RXE_WRITE_OR_SEND_MASK) {
-		err = rxe_init_payload(qp, wqe, pkt, payload, skb);
+		err = rxe_init_payload(qp, wqe, pkt, pad, payload, skb, frag);
 		if (err)
 			goto err_out;
 	}
 
-	if (pad) {
-		padp = payload_addr(pkt) + payload;
-		memset(padp, 0, pad);
-	}
+	/* handle pad and icrc */
+	err = rxe_prepare_pad_icrc(pkt, skb, payload, frag);
+	if (err)
+		goto err_out;
 
 	/* IP and UDP network headers */
 	err = rxe_prepare(av, pkt, skb);
-- 
2.34.1