rdma/siw: receive path

Broken up commit to add the Soft iWarp RDMA driver.
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/siw/siw_qp_rx.c

+// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
+
+/* Authors: Bernard Metzler <bmt@zurich.ibm.com> */
+/* Copyright (c) 2008-2019, IBM Corporation */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/scatterlist.h>
+#include <linux/highmem.h>
+
+#include <rdma/iw_cm.h>
+#include <rdma/ib_verbs.h>
+
+#include "siw.h"
+#include "siw_verbs.h"
+#include "siw_mem.h"
+
+/*
+ * siw_rx_umem()
+ *
+ * Receive data of @len into target referenced by @dest_addr.
+ *
+ * @srx:	Receive Context
+ * @umem:	siw representation of target memory
+ * @dest_addr:	user virtual address
+ * @len:	number of bytes to place
+ */
+static int siw_rx_umem(struct siw_rx_stream *srx, struct siw_umem *umem,
+		       u64 dest_addr, int len)
+{
+	int copied = 0;
+
+	while (len) {
+		struct page *p;
+		int pg_off, bytes, rv;
+		void *dest;
+
+		p = siw_get_upage(umem, dest_addr);
+		if (unlikely(!p)) {
+			pr_warn("siw: %s: [QP %u]: bogus addr: %p, %p\n",
+				__func__, qp_id(rx_qp(srx)),
+				(void *)dest_addr, (void *)umem->fp_addr);
+			/* siw internal error */
+			srx->skb_copied += copied;
+			srx->skb_new -= copied;
+
+			return -EFAULT;
+		}
+		pg_off = dest_addr & ~PAGE_MASK;
+		bytes = min(len, (int)PAGE_SIZE - pg_off);
+
+		siw_dbg_qp(rx_qp(srx), "page %p, bytes=%u\n", p, bytes);
+
+		dest = kmap_atomic(p);
+		rv = skb_copy_bits(srx->skb, srx->skb_offset, dest + pg_off,
+				   bytes);
+
+		if (unlikely(rv)) {
+			kunmap_atomic(dest);
+			srx->skb_copied += copied;
+			srx->skb_new -= copied;
+
+			pr_warn("siw: [QP %u]: %s, len %d, page %p, rv %d\n",
+				qp_id(rx_qp(srx)), __func__, len, p, rv);
+
+			return -EFAULT;
+		}
+		if (srx->mpa_crc_hd) {
+			if (rx_qp(srx)->kernel_verbs) {
+				crypto_shash_update(srx->mpa_crc_hd,
+					(u8 *)(dest + pg_off), bytes);
+				kunmap_atomic(dest);
+			} else {
+				kunmap_atomic(dest);
+				/*
+				 * Do CRC on original, not target buffer.
+				 * Some user land applications may
+				 * concurrently write the target buffer,
+				 * which would yield a broken CRC.
+				 * Walking the skb twice is very ineffcient.
+				 * Folding the CRC into skb_copy_bits()
+				 * would be much better, but is currently
+				 * not supported.
+				 */
+				siw_crc_skb(srx, bytes);
+			}
+		} else {
+			kunmap_atomic(dest);
+		}
+		srx->skb_offset += bytes;
+		copied += bytes;
+		len -= bytes;
+		dest_addr += bytes;
+		pg_off = 0;
+	}
+	srx->skb_copied += copied;
+	srx->skb_new -= copied;
+
+	return copied;
+}
+
+static int siw_rx_kva(struct siw_rx_stream *srx, void *kva, int len)
+{
+	int rv;
+
+	siw_dbg_qp(rx_qp(srx), "kva: 0x%p, len: %u\n", kva, len);
+
+	rv = skb_copy_bits(srx->skb, srx->skb_offset, kva, len);
+	if (unlikely(rv)) {
+		pr_warn("siw: [QP %u]: %s, len %d, kva 0x%p, rv %d\n",
+			qp_id(rx_qp(srx)), __func__, len, kva, rv);
+
+		return rv;
+	}
+	if (srx->mpa_crc_hd)
+		crypto_shash_update(srx->mpa_crc_hd, (u8 *)kva, len);
+
+	srx->skb_offset += len;
+	srx->skb_copied += len;
+	srx->skb_new -= len;
+
+	return len;
+}
+
+static int siw_rx_pbl(struct siw_rx_stream *srx, int *pbl_idx,
+		      struct siw_mem *mem, u64 addr, int len)
+{
+	struct siw_pbl *pbl = mem->pbl;
+	u64 offset = addr - mem->va;
+	int copied = 0;
+
+	while (len) {
+		int bytes;
+		u64 buf_addr =
+			siw_pbl_get_buffer(pbl, offset, &bytes, pbl_idx);
+		if (!buf_addr)
+			break;
+
+		bytes = min(bytes, len);
+		if (siw_rx_kva(srx, (void *)buf_addr, bytes) == bytes) {
+			copied += bytes;
+			offset += bytes;
+			len -= bytes;
+		} else {
+			break;
+		}
+	}
+	return copied;
+}
+
+/*
+ * siw_rresp_check_ntoh()
+ *
+ * Check incoming RRESP fragment header against expected
+ * header values and update expected values for potential next
+ * fragment.
+ *
+ * NOTE: This function must be called only if a RRESP DDP segment
+ *       starts but not for fragmented consecutive pieces of an
+ *       already started DDP segment.
+ */
+static int siw_rresp_check_ntoh(struct siw_rx_stream *srx,
+				struct siw_rx_fpdu *frx)
+{
+	struct iwarp_rdma_rresp *rresp = &srx->hdr.rresp;
+	struct siw_wqe *wqe = &frx->wqe_active;
+	enum ddp_ecode ecode;
+
+	u32 sink_stag = be32_to_cpu(rresp->sink_stag);
+	u64 sink_to = be64_to_cpu(rresp->sink_to);
+
+	if (frx->first_ddp_seg) {
+		srx->ddp_stag = wqe->sqe.sge[0].lkey;
+		srx->ddp_to = wqe->sqe.sge[0].laddr;
+		frx->pbl_idx = 0;
+	}
+	/* Below checks extend beyond the semantics of DDP, and
+	 * into RDMAP:
+	 * We check if the read response matches exactly the
+	 * read request which was send to the remote peer to
+	 * trigger this read response. RFC5040/5041 do not
+	 * always have a proper error code for the detected
+	 * error cases. We choose 'base or bounds error' for
+	 * cases where the inbound STag is valid, but offset
+	 * or length do not match our response receive state.
+	 */
+	if (unlikely(srx->ddp_stag != sink_stag)) {
+		pr_warn("siw: [QP %u]: rresp stag: %08x != %08x\n",
+			qp_id(rx_qp(srx)), sink_stag, srx->ddp_stag);
+		ecode = DDP_ECODE_T_INVALID_STAG;
+		goto error;
+	}
+	if (unlikely(srx->ddp_to != sink_to)) {
+		pr_warn("siw: [QP %u]: rresp off: %016llx != %016llx\n",
+			qp_id(rx_qp(srx)), (unsigned long long)sink_to,
+			(unsigned long long)srx->ddp_to);
+		ecode = DDP_ECODE_T_BASE_BOUNDS;
+		goto error;
+	}
+	if (unlikely(!frx->more_ddp_segs &&
+		     (wqe->processed + srx->fpdu_part_rem != wqe->bytes))) {
+		pr_warn("siw: [QP %u]: rresp len: %d != %d\n",
+			qp_id(rx_qp(srx)),
+			wqe->processed + srx->fpdu_part_rem, wqe->bytes);
+		ecode = DDP_ECODE_T_BASE_BOUNDS;
+		goto error;
+	}
+	return 0;
+error:
+	siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_DDP,
+			   DDP_ETYPE_TAGGED_BUF, ecode, 0);
+	return -EINVAL;
+}
+
+/*
+ * siw_write_check_ntoh()
+ *
+ * Check incoming WRITE fragment header against expected
+ * header values and update expected values for potential next
+ * fragment
+ *
+ * NOTE: This function must be called only if a WRITE DDP segment
+ *       starts but not for fragmented consecutive pieces of an
+ *       already started DDP segment.
+ */
+static int siw_write_check_ntoh(struct siw_rx_stream *srx,
+				struct siw_rx_fpdu *frx)
+{
+	struct iwarp_rdma_write *write = &srx->hdr.rwrite;
+	enum ddp_ecode ecode;
+
+	u32 sink_stag = be32_to_cpu(write->sink_stag);
+	u64 sink_to = be64_to_cpu(write->sink_to);
+
+	if (frx->first_ddp_seg) {
+		srx->ddp_stag = sink_stag;
+		srx->ddp_to = sink_to;
+		frx->pbl_idx = 0;
+	} else {
+		if (unlikely(srx->ddp_stag != sink_stag)) {
+			pr_warn("siw: [QP %u]: write stag: %08x != %08x\n",
+				qp_id(rx_qp(srx)), sink_stag,
+				srx->ddp_stag);
+			ecode = DDP_ECODE_T_INVALID_STAG;
+			goto error;
+		}
+		if (unlikely(srx->ddp_to != sink_to)) {
+			pr_warn("siw: [QP %u]: write off: %016llx != %016llx\n",
+				qp_id(rx_qp(srx)),
+				(unsigned long long)sink_to,
+				(unsigned long long)srx->ddp_to);
+			ecode = DDP_ECODE_T_BASE_BOUNDS;
+			goto error;
+		}
+	}
+	return 0;
+error:
+	siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_DDP,
+			   DDP_ETYPE_TAGGED_BUF, ecode, 0);
+	return -EINVAL;
+}
+
+/*
+ * siw_send_check_ntoh()
+ *
+ * Check incoming SEND fragment header against expected
+ * header values and update expected MSN if no next
+ * fragment expected
+ *
+ * NOTE: This function must be called only if a SEND DDP segment
+ *       starts but not for fragmented consecutive pieces of an
+ *       already started DDP segment.
+ */
+static int siw_send_check_ntoh(struct siw_rx_stream *srx,
+			       struct siw_rx_fpdu *frx)
+{
+	struct iwarp_send_inv *send = &srx->hdr.send_inv;
+	struct siw_wqe *wqe = &frx->wqe_active;
+	enum ddp_ecode ecode;
+
+	u32 ddp_msn = be32_to_cpu(send->ddp_msn);
+	u32 ddp_mo = be32_to_cpu(send->ddp_mo);
+	u32 ddp_qn = be32_to_cpu(send->ddp_qn);
+
+	if (unlikely(ddp_qn != RDMAP_UNTAGGED_QN_SEND)) {
+		pr_warn("siw: [QP %u]: invalid ddp qn %d for send\n",
+			qp_id(rx_qp(srx)), ddp_qn);
+		ecode = DDP_ECODE_UT_INVALID_QN;
+		goto error;
+	}
+	if (unlikely(ddp_msn != srx->ddp_msn[RDMAP_UNTAGGED_QN_SEND])) {
+		pr_warn("siw: [QP %u]: send msn: %u != %u\n",
+			qp_id(rx_qp(srx)), ddp_msn,
+			srx->ddp_msn[RDMAP_UNTAGGED_QN_SEND]);
+		ecode = DDP_ECODE_UT_INVALID_MSN_RANGE;
+		goto error;
+	}
+	if (unlikely(ddp_mo != wqe->processed)) {
+		pr_warn("siw: [QP %u], send mo: %u != %u\n",
+			qp_id(rx_qp(srx)), ddp_mo, wqe->processed);
+		ecode = DDP_ECODE_UT_INVALID_MO;
+		goto error;
+	}
+	if (frx->first_ddp_seg) {
+		/* initialize user memory write position */
+		frx->sge_idx = 0;
+		frx->sge_off = 0;
+		frx->pbl_idx = 0;
+
+		/* only valid for SEND_INV and SEND_SE_INV operations */
+		srx->inval_stag = be32_to_cpu(send->inval_stag);
+	}
+	if (unlikely(wqe->bytes < wqe->processed + srx->fpdu_part_rem)) {
+		siw_dbg_qp(rx_qp(srx), "receive space short: %d - %d < %d\n",
+			   wqe->bytes, wqe->processed, srx->fpdu_part_rem);
+		wqe->wc_status = SIW_WC_LOC_LEN_ERR;
+		ecode = DDP_ECODE_UT_INVALID_MSN_NOBUF;
+		goto error;
+	}
+	return 0;
+error:
+	siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_DDP,
+			   DDP_ETYPE_UNTAGGED_BUF, ecode, 0);
+	return -EINVAL;
+}
+
+static struct siw_wqe *siw_rqe_get(struct siw_qp *qp)
+{
+	struct siw_rqe *rqe;
+	struct siw_srq *srq;
+	struct siw_wqe *wqe = NULL;
+	bool srq_event = false;
+	unsigned long flags;
+
+	srq = qp->srq;
+	if (srq) {
+		spin_lock_irqsave(&srq->lock, flags);
+		if (unlikely(!srq->num_rqe))
+			goto out;
+
+		rqe = &srq->recvq[srq->rq_get % srq->num_rqe];
+	} else {
+		if (unlikely(!qp->recvq))
+			goto out;
+
+		rqe = &qp->recvq[qp->rq_get % qp->attrs.rq_size];
+	}
+	if (likely(rqe->flags == SIW_WQE_VALID)) {
+		int num_sge = rqe->num_sge;
+
+		if (likely(num_sge <= SIW_MAX_SGE)) {
+			int i = 0;
+
+			wqe = rx_wqe(&qp->rx_untagged);
+			rx_type(wqe) = SIW_OP_RECEIVE;
+			wqe->wr_status = SIW_WR_INPROGRESS;
+			wqe->bytes = 0;
+			wqe->processed = 0;
+
+			wqe->rqe.id = rqe->id;
+			wqe->rqe.num_sge = num_sge;
+
+			while (i < num_sge) {
+				wqe->rqe.sge[i].laddr = rqe->sge[i].laddr;
+				wqe->rqe.sge[i].lkey = rqe->sge[i].lkey;
+				wqe->rqe.sge[i].length = rqe->sge[i].length;
+				wqe->bytes += wqe->rqe.sge[i].length;
+				wqe->mem[i] = NULL;
+				i++;
+			}
+			/* can be re-used by appl */
+			smp_store_mb(rqe->flags, 0);
+		} else {
+			siw_dbg_qp(qp, "too many sge's: %d\n", rqe->num_sge);
+			if (srq)
+				spin_unlock_irqrestore(&srq->lock, flags);
+			return NULL;
+		}
+		if (!srq) {
+			qp->rq_get++;
+		} else {
+			if (srq->armed) {
+				/* Test SRQ limit */
+				u32 off = (srq->rq_get + srq->limit) %
+					  srq->num_rqe;
+				struct siw_rqe *rqe2 = &srq->recvq[off];
+
+				if (!(rqe2->flags & SIW_WQE_VALID)) {
+					srq->armed = 0;
+					srq_event = true;
+				}
+			}
+			srq->rq_get++;
+		}
+	}
+out:
+	if (srq) {
+		spin_unlock_irqrestore(&srq->lock, flags);
+		if (srq_event)
+			siw_srq_event(srq, IB_EVENT_SRQ_LIMIT_REACHED);
+	}
+	return wqe;
+}
+
+/*
+ * siw_proc_send:
+ *
+ * Process one incoming SEND and place data into memory referenced by
+ * receive wqe.
+ *
+ * Function supports partially received sends (suspending/resuming
+ * current receive wqe processing)
+ *
+ * return value:
+ *	0:       reached the end of a DDP segment
+ *	-EAGAIN: to be called again to finish the DDP segment
+ */
+int siw_proc_send(struct siw_qp *qp)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	struct siw_rx_fpdu *frx = &qp->rx_untagged;
+	struct siw_wqe *wqe;
+	u32 data_bytes; /* all data bytes available */
+	u32 rcvd_bytes; /* sum of data bytes rcvd */
+	int rv = 0;
+
+	if (frx->first_ddp_seg) {
+		wqe = siw_rqe_get(qp);
+		if (unlikely(!wqe)) {
+			siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+					   DDP_ETYPE_UNTAGGED_BUF,
+					   DDP_ECODE_UT_INVALID_MSN_NOBUF, 0);
+			return -ENOENT;
+		}
+	} else {
+		wqe = rx_wqe(frx);
+	}
+	if (srx->state == SIW_GET_DATA_START) {
+		rv = siw_send_check_ntoh(srx, frx);
+		if (unlikely(rv)) {
+			siw_qp_event(qp, IB_EVENT_QP_FATAL);
+			return rv;
+		}
+		if (!srx->fpdu_part_rem) /* zero length SEND */
+			return 0;
+	}
+	data_bytes = min(srx->fpdu_part_rem, srx->skb_new);
+	rcvd_bytes = 0;
+
+	/* A zero length SEND will skip below loop */
+	while (data_bytes) {
+		struct ib_pd *pd;
+		struct siw_mem **mem, *mem_p;
+		struct siw_sge *sge;
+		u32 sge_bytes; /* data bytes avail for SGE */
+
+		sge = &wqe->rqe.sge[frx->sge_idx];
+
+		if (!sge->length) {
+			/* just skip empty sge's */
+			frx->sge_idx++;
+			frx->sge_off = 0;
+			frx->pbl_idx = 0;
+			continue;
+		}
+		sge_bytes = min(data_bytes, sge->length - frx->sge_off);
+		mem = &wqe->mem[frx->sge_idx];
+
+		/*
+		 * check with QP's PD if no SRQ present, SRQ's PD otherwise
+		 */
+		pd = qp->srq == NULL ? qp->pd : qp->srq->base_srq.pd;
+
+		rv = siw_check_sge(pd, sge, mem, IB_ACCESS_LOCAL_WRITE,
+				   frx->sge_off, sge_bytes);
+		if (unlikely(rv)) {
+			siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+					   DDP_ETYPE_CATASTROPHIC,
+					   DDP_ECODE_CATASTROPHIC, 0);
+
+			siw_qp_event(qp, IB_EVENT_QP_ACCESS_ERR);
+			break;
+		}
+		mem_p = *mem;
+		if (mem_p->mem_obj == NULL)
+			rv = siw_rx_kva(srx,
+					(void *)(sge->laddr + frx->sge_off),
+					sge_bytes);
+		else if (!mem_p->is_pbl)
+			rv = siw_rx_umem(srx, mem_p->umem,
+					 sge->laddr + frx->sge_off, sge_bytes);
+		else
+			rv = siw_rx_pbl(srx, &frx->pbl_idx, mem_p,
+					sge->laddr + frx->sge_off, sge_bytes);
+
+		if (unlikely(rv != sge_bytes)) {
+			wqe->processed += rcvd_bytes;
+
+			siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+					   DDP_ETYPE_CATASTROPHIC,
+					   DDP_ECODE_CATASTROPHIC, 0);
+			return -EINVAL;
+		}
+		frx->sge_off += rv;
+
+		if (frx->sge_off == sge->length) {
+			frx->sge_idx++;
+			frx->sge_off = 0;
+			frx->pbl_idx = 0;
+		}
+		data_bytes -= rv;
+		rcvd_bytes += rv;
+
+		srx->fpdu_part_rem -= rv;
+		srx->fpdu_part_rcvd += rv;
+	}
+	wqe->processed += rcvd_bytes;
+
+	if (!srx->fpdu_part_rem)
+		return 0;
+
+	return (rv < 0) ? rv : -EAGAIN;
+}
+
+/*
+ * siw_proc_write:
+ *
+ * Place incoming WRITE after referencing and checking target buffer
+
+ * Function supports partially received WRITEs (suspending/resuming
+ * current receive processing)
+ *
+ * return value:
+ *	0:       reached the end of a DDP segment
+ *	-EAGAIN: to be called again to finish the DDP segment
+ */
+int siw_proc_write(struct siw_qp *qp)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	struct siw_rx_fpdu *frx = &qp->rx_tagged;
+	struct siw_mem *mem;
+	int bytes, rv;
+
+	if (srx->state == SIW_GET_DATA_START) {
+		if (!srx->fpdu_part_rem) /* zero length WRITE */
+			return 0;
+
+		rv = siw_write_check_ntoh(srx, frx);
+		if (unlikely(rv)) {
+			siw_qp_event(qp, IB_EVENT_QP_FATAL);
+			return rv;
+		}
+	}
+	bytes = min(srx->fpdu_part_rem, srx->skb_new);
+
+	if (frx->first_ddp_seg) {
+		struct siw_wqe *wqe = rx_wqe(frx);
+
+		rx_mem(frx) = siw_mem_id2obj(qp->sdev, srx->ddp_stag >> 8);
+		if (unlikely(!rx_mem(frx))) {
+			siw_dbg_qp(qp,
+				   "sink stag not found/invalid, stag 0x%08x\n",
+				   srx->ddp_stag);
+
+			siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+					   DDP_ETYPE_TAGGED_BUF,
+					   DDP_ECODE_T_INVALID_STAG, 0);
+			return -EINVAL;
+		}
+		wqe->rqe.num_sge = 1;
+		rx_type(wqe) = SIW_OP_WRITE;
+		wqe->wr_status = SIW_WR_INPROGRESS;
+	}
+	mem = rx_mem(frx);
+
+	/*
+	 * Check if application re-registered memory with different
+	 * key field of STag.
+	 */
+	if (unlikely(mem->stag != srx->ddp_stag)) {
+		siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+				   DDP_ETYPE_TAGGED_BUF,
+				   DDP_ECODE_T_INVALID_STAG, 0);
+		return -EINVAL;
+	}
+	rv = siw_check_mem(qp->pd, mem, srx->ddp_to + srx->fpdu_part_rcvd,
+			   IB_ACCESS_REMOTE_WRITE, bytes);
+	if (unlikely(rv)) {
+		siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+				   DDP_ETYPE_TAGGED_BUF, siw_tagged_error(-rv),
+				   0);
+
+		siw_qp_event(qp, IB_EVENT_QP_ACCESS_ERR);
+
+		return -EINVAL;
+	}
+
+	if (mem->mem_obj == NULL)
+		rv = siw_rx_kva(srx,
+				(void *)(srx->ddp_to + srx->fpdu_part_rcvd),
+				bytes);
+	else if (!mem->is_pbl)
+		rv = siw_rx_umem(srx, mem->umem,
+				 srx->ddp_to + srx->fpdu_part_rcvd, bytes);
+	else
+		rv = siw_rx_pbl(srx, &frx->pbl_idx, mem,
+				srx->ddp_to + srx->fpdu_part_rcvd, bytes);
+
+	if (unlikely(rv != bytes)) {
+		siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+				   DDP_ETYPE_CATASTROPHIC,
+				   DDP_ECODE_CATASTROPHIC, 0);
+		return -EINVAL;
+	}
+	srx->fpdu_part_rem -= rv;
+	srx->fpdu_part_rcvd += rv;
+
+	if (!srx->fpdu_part_rem) {
+		srx->ddp_to += srx->fpdu_part_rcvd;
+		return 0;
+	}
+	return -EAGAIN;
+}
+
+/*
+ * Inbound RREQ's cannot carry user data.
+ */
+int siw_proc_rreq(struct siw_qp *qp)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+
+	if (!srx->fpdu_part_rem)
+		return 0;
+
+	pr_warn("siw: [QP %u]: rreq with mpa len %d\n", qp_id(qp),
+		be16_to_cpu(srx->hdr.ctrl.mpa_len));
+
+	return -EPROTO;
+}
+
+/*
+ * siw_init_rresp:
+ *
+ * Process inbound RDMA READ REQ. Produce a pseudo READ RESPONSE WQE.
+ * Put it at the tail of the IRQ, if there is another WQE currently in
+ * transmit processing. If not, make it the current WQE to be processed
+ * and schedule transmit processing.
+ *
+ * Can be called from softirq context and from process
+ * context (RREAD socket loopback case!)
+ *
+ * return value:
+ *	0:      success,
+ *		failure code otherwise
+ */
+
+static int siw_init_rresp(struct siw_qp *qp, struct siw_rx_stream *srx)
+{
+	struct siw_wqe *tx_work = tx_wqe(qp);
+	struct siw_sqe *resp;
+
+	uint64_t raddr = be64_to_cpu(srx->hdr.rreq.sink_to),
+		 laddr = be64_to_cpu(srx->hdr.rreq.source_to);
+	uint32_t length = be32_to_cpu(srx->hdr.rreq.read_size),
+		 lkey = be32_to_cpu(srx->hdr.rreq.source_stag),
+		 rkey = be32_to_cpu(srx->hdr.rreq.sink_stag),
+		 msn = be32_to_cpu(srx->hdr.rreq.ddp_msn);
+
+	int run_sq = 1, rv = 0;
+	unsigned long flags;
+
+	if (unlikely(msn != srx->ddp_msn[RDMAP_UNTAGGED_QN_RDMA_READ])) {
+		siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+				   DDP_ETYPE_UNTAGGED_BUF,
+				   DDP_ECODE_UT_INVALID_MSN_RANGE, 0);
+		return -EPROTO;
+	}
+	spin_lock_irqsave(&qp->sq_lock, flags);
+
+	if (tx_work->wr_status == SIW_WR_IDLE) {
+		/*
+		 * immediately schedule READ response w/o
+		 * consuming IRQ entry: IRQ must be empty.
+		 */
+		tx_work->processed = 0;
+		tx_work->mem[0] = NULL;
+		tx_work->wr_status = SIW_WR_QUEUED;
+		resp = &tx_work->sqe;
+	} else {
+		resp = irq_alloc_free(qp);
+		run_sq = 0;
+	}
+	if (likely(resp)) {
+		resp->opcode = SIW_OP_READ_RESPONSE;
+
+		resp->sge[0].length = length;
+		resp->sge[0].laddr = laddr;
+		resp->sge[0].lkey = lkey;
+
+		/* Keep aside message sequence number for potential
+		 * error reporting during Read Response generation.
+		 */
+		resp->sge[1].length = msn;
+
+		resp->raddr = raddr;
+		resp->rkey = rkey;
+		resp->num_sge = length ? 1 : 0;
+
+		/* RRESP now valid as current TX wqe or placed into IRQ */
+		smp_store_mb(resp->flags, SIW_WQE_VALID);
+	} else {
+		pr_warn("siw: [QP %u]: irq %d exceeded %d\n", qp_id(qp),
+			qp->irq_put % qp->attrs.irq_size, qp->attrs.irq_size);
+
+		siw_init_terminate(qp, TERM_ERROR_LAYER_RDMAP,
+				   RDMAP_ETYPE_REMOTE_OPERATION,
+				   RDMAP_ECODE_CATASTROPHIC_STREAM, 0);
+		rv = -EPROTO;
+	}
+
+	spin_unlock_irqrestore(&qp->sq_lock, flags);
+
+	if (run_sq)
+		rv = siw_sq_start(qp);
+
+	return rv;
+}
+
+/*
+ * Only called at start of Read.Resonse processing.
+ * Transfer pending Read from tip of ORQ into currrent rx wqe,
+ * but keep ORQ entry valid until Read.Response processing done.
+ * No Queue locking needed.
+ */
+static int siw_orqe_start_rx(struct siw_qp *qp)
+{
+	struct siw_sqe *orqe;
+	struct siw_wqe *wqe = NULL;
+
+	/* make sure ORQ indices are current */
+	smp_mb();
+
+	orqe = orq_get_current(qp);
+	if (READ_ONCE(orqe->flags) & SIW_WQE_VALID) {
+		/* RRESP is a TAGGED RDMAP operation */
+		wqe = rx_wqe(&qp->rx_tagged);
+		wqe->sqe.id = orqe->id;
+		wqe->sqe.opcode = orqe->opcode;
+		wqe->sqe.sge[0].laddr = orqe->sge[0].laddr;
+		wqe->sqe.sge[0].lkey = orqe->sge[0].lkey;
+		wqe->sqe.sge[0].length = orqe->sge[0].length;
+		wqe->sqe.flags = orqe->flags;
+		wqe->sqe.num_sge = 1;
+		wqe->bytes = orqe->sge[0].length;
+		wqe->processed = 0;
+		wqe->mem[0] = NULL;
+		/* make sure WQE is completely written before valid */
+		smp_wmb();
+		wqe->wr_status = SIW_WR_INPROGRESS;
+
+		return 0;
+	}
+	return -EPROTO;
+}
+
+/*
+ * siw_proc_rresp:
+ *
+ * Place incoming RRESP data into memory referenced by RREQ WQE
+ * which is at the tip of the ORQ
+ *
+ * Function supports partially received RRESP's (suspending/resuming
+ * current receive processing)
+ */
+int siw_proc_rresp(struct siw_qp *qp)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	struct siw_rx_fpdu *frx = &qp->rx_tagged;
+	struct siw_wqe *wqe = rx_wqe(frx);
+	struct siw_mem **mem, *mem_p;
+	struct siw_sge *sge;
+	int bytes, rv;
+
+	if (frx->first_ddp_seg) {
+		if (unlikely(wqe->wr_status != SIW_WR_IDLE)) {
+			pr_warn("siw: [QP %u]: proc RRESP: status %d, op %d\n",
+				qp_id(qp), wqe->wr_status, wqe->sqe.opcode);
+			rv = -EPROTO;
+			goto error_term;
+		}
+		/*
+		 * fetch pending RREQ from orq
+		 */
+		rv = siw_orqe_start_rx(qp);
+		if (rv) {
+			pr_warn("siw: [QP %u]: ORQ empty at idx %d\n",
+				qp_id(qp), qp->orq_get % qp->attrs.orq_size);
+			goto error_term;
+		}
+		rv = siw_rresp_check_ntoh(srx, frx);
+		if (unlikely(rv)) {
+			siw_qp_event(qp, IB_EVENT_QP_FATAL);
+			return rv;
+		}
+	} else {
+		if (unlikely(wqe->wr_status != SIW_WR_INPROGRESS)) {
+			pr_warn("siw: [QP %u]: resume RRESP: status %d\n",
+				qp_id(qp), wqe->wr_status);
+			rv = -EPROTO;
+			goto error_term;
+		}
+	}
+	if (!srx->fpdu_part_rem) /* zero length RRESPONSE */
+		return 0;
+
+	sge = wqe->sqe.sge; /* there is only one */
+	mem = &wqe->mem[0];
+
+	if (!(*mem)) {
+		/*
+		 * check target memory which resolves memory on first fragment
+		 */
+		rv = siw_check_sge(qp->pd, sge, mem, IB_ACCESS_LOCAL_WRITE, 0,
+				   wqe->bytes);
+		if (unlikely(rv)) {
+			siw_dbg_qp(qp, "target mem check: %d\n", rv);
+			wqe->wc_status = SIW_WC_LOC_PROT_ERR;
+
+			siw_init_terminate(qp, TERM_ERROR_LAYER_DDP,
+					   DDP_ETYPE_TAGGED_BUF,
+					   siw_tagged_error(-rv), 0);
+
+			siw_qp_event(qp, IB_EVENT_QP_ACCESS_ERR);
+
+			return -EINVAL;
+		}
+	}
+	mem_p = *mem;
+
+	bytes = min(srx->fpdu_part_rem, srx->skb_new);
+
+	if (mem_p->mem_obj == NULL)
+		rv = siw_rx_kva(srx, (void *)(sge->laddr + wqe->processed),
+				bytes);
+	else if (!mem_p->is_pbl)
+		rv = siw_rx_umem(srx, mem_p->umem, sge->laddr + wqe->processed,
+				 bytes);
+	else
+		rv = siw_rx_pbl(srx, &frx->pbl_idx, mem_p,
+				sge->laddr + wqe->processed, bytes);
+	if (rv != bytes) {
+		wqe->wc_status = SIW_WC_GENERAL_ERR;
+		rv = -EINVAL;
+		goto error_term;
+	}
+	srx->fpdu_part_rem -= rv;
+	srx->fpdu_part_rcvd += rv;
+	wqe->processed += rv;
+
+	if (!srx->fpdu_part_rem) {
+		srx->ddp_to += srx->fpdu_part_rcvd;
+		return 0;
+	}
+	return -EAGAIN;
+
+error_term:
+	siw_init_terminate(qp, TERM_ERROR_LAYER_DDP, DDP_ETYPE_CATASTROPHIC,
+			   DDP_ECODE_CATASTROPHIC, 0);
+	return rv;
+}
+
+int siw_proc_terminate(struct siw_qp *qp)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	struct sk_buff *skb = srx->skb;
+	struct iwarp_terminate *term = &srx->hdr.terminate;
+	union iwarp_hdr term_info;
+	u8 *infop = (u8 *)&term_info;
+	enum rdma_opcode op;
+	u16 to_copy = sizeof(struct iwarp_ctrl);
+
+	pr_warn("siw: got TERMINATE. layer %d, type %d, code %d\n",
+		__rdmap_term_layer(term), __rdmap_term_etype(term),
+		__rdmap_term_ecode(term));
+
+	if (be32_to_cpu(term->ddp_qn) != RDMAP_UNTAGGED_QN_TERMINATE ||
+	    be32_to_cpu(term->ddp_msn) !=
+		    qp->rx_stream.ddp_msn[RDMAP_UNTAGGED_QN_TERMINATE] ||
+	    be32_to_cpu(term->ddp_mo) != 0) {
+		pr_warn("siw: rx bogus TERM [QN x%08x, MSN x%08x, MO x%08x]\n",
+			be32_to_cpu(term->ddp_qn), be32_to_cpu(term->ddp_msn),
+			be32_to_cpu(term->ddp_mo));
+		return -ECONNRESET;
+	}
+	/*
+	 * Receive remaining pieces of TERM if indicated
+	 */
+	if (!term->flag_m)
+		return -ECONNRESET;
+
+	/* Do not take the effort to reassemble a network fragmented
+	 * TERM message
+	 */
+	if (srx->skb_new < sizeof(struct iwarp_ctrl_tagged))
+		return -ECONNRESET;
+
+	memset(infop, 0, sizeof(term_info));
+
+	skb_copy_bits(skb, srx->skb_offset, infop, to_copy);
+
+	op = __rdmap_get_opcode(&term_info.ctrl);
+	if (op >= RDMAP_TERMINATE)
+		goto out;
+
+	infop += to_copy;
+	srx->skb_offset += to_copy;
+	srx->skb_new -= to_copy;
+	srx->skb_copied += to_copy;
+	srx->fpdu_part_rcvd += to_copy;
+	srx->fpdu_part_rem -= to_copy;
+
+	to_copy = iwarp_pktinfo[op].hdr_len - to_copy;
+
+	/* Again, no network fragmented TERM's */
+	if (to_copy + MPA_CRC_SIZE > srx->skb_new)
+		return -ECONNRESET;
+
+	skb_copy_bits(skb, srx->skb_offset, infop, to_copy);
+
+	if (term->flag_r) {
+		siw_dbg_qp(qp, "TERM reports RDMAP hdr type %u, len %u (%s)\n",
+			   op, be16_to_cpu(term_info.ctrl.mpa_len),
+			   term->flag_m ? "valid" : "invalid");
+	} else if (term->flag_d) {
+		siw_dbg_qp(qp, "TERM reports DDP hdr type %u, len %u (%s)\n",
+			   op, be16_to_cpu(term_info.ctrl.mpa_len),
+			   term->flag_m ? "valid" : "invalid");
+	}
+out:
+	srx->skb_new -= to_copy;
+	srx->skb_offset += to_copy;
+	srx->skb_copied += to_copy;
+	srx->fpdu_part_rcvd += to_copy;
+	srx->fpdu_part_rem -= to_copy;
+
+	return -ECONNRESET;
+}
+
+static int siw_get_trailer(struct siw_qp *qp, struct siw_rx_stream *srx)
+{
+	struct sk_buff *skb = srx->skb;
+	u8 *tbuf = (u8 *)&srx->trailer.crc - srx->pad;
+	__wsum crc_in, crc_own = 0;
+
+	siw_dbg_qp(qp, "expected %d, available %d, pad %u\n",
+		   srx->fpdu_part_rem, srx->skb_new, srx->pad);
+
+	if (srx->skb_new < srx->fpdu_part_rem)
+		return -EAGAIN;
+
+	skb_copy_bits(skb, srx->skb_offset, tbuf, srx->fpdu_part_rem);
+
+	if (srx->mpa_crc_hd && srx->pad)
+		crypto_shash_update(srx->mpa_crc_hd, tbuf, srx->pad);
+
+	srx->skb_new -= srx->fpdu_part_rem;
+	srx->skb_offset += srx->fpdu_part_rem;
+	srx->skb_copied += srx->fpdu_part_rem;
+
+	if (!srx->mpa_crc_hd)
+		return 0;
+
+	/*
+	 * CRC32 is computed, transmitted and received directly in NBO,
+	 * so there's never a reason to convert byte order.
+	 */
+	crypto_shash_final(srx->mpa_crc_hd, (u8 *)&crc_own);
+	crc_in = (__force __wsum)srx->trailer.crc;
+
+	if (unlikely(crc_in != crc_own)) {
+		pr_warn("siw: crc error. in: %08x, own %08x, op %u\n",
+			crc_in, crc_own, qp->rx_stream.rdmap_op);
+
+		siw_init_terminate(qp, TERM_ERROR_LAYER_LLP,
+				   LLP_ETYPE_MPA,
+				   LLP_ECODE_RECEIVED_CRC, 0);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#define MIN_DDP_HDR sizeof(struct iwarp_ctrl_tagged)
+
+static int siw_get_hdr(struct siw_rx_stream *srx)
+{
+	struct sk_buff *skb = srx->skb;
+	struct siw_qp *qp = rx_qp(srx);
+	struct iwarp_ctrl *c_hdr = &srx->hdr.ctrl;
+	struct siw_rx_fpdu *frx;
+	u8 opcode;
+	int bytes;
+
+	if (srx->fpdu_part_rcvd < MIN_DDP_HDR) {
+		/*
+		 * copy a mimimum sized (tagged) DDP frame control part
+		 */
+		bytes = min_t(int, srx->skb_new,
+			      MIN_DDP_HDR - srx->fpdu_part_rcvd);
+
+		skb_copy_bits(skb, srx->skb_offset,
+			      (char *)c_hdr + srx->fpdu_part_rcvd, bytes);
+
+		srx->fpdu_part_rcvd += bytes;
+
+		srx->skb_new -= bytes;
+		srx->skb_offset += bytes;
+		srx->skb_copied += bytes;
+
+		if (srx->fpdu_part_rcvd < MIN_DDP_HDR)
+			return -EAGAIN;
+
+		if (unlikely(__ddp_get_version(c_hdr) != DDP_VERSION)) {
+			enum ddp_etype etype;
+			enum ddp_ecode ecode;
+
+			pr_warn("siw: received ddp version unsupported %d\n",
+				__ddp_get_version(c_hdr));
+
+			if (c_hdr->ddp_rdmap_ctrl & DDP_FLAG_TAGGED) {
+				etype = DDP_ETYPE_TAGGED_BUF;
+				ecode = DDP_ECODE_T_VERSION;
+			} else {
+				etype = DDP_ETYPE_UNTAGGED_BUF;
+				ecode = DDP_ECODE_UT_VERSION;
+			}
+			siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_DDP,
+					   etype, ecode, 0);
+			return -EINVAL;
+		}
+		if (unlikely(__rdmap_get_version(c_hdr) != RDMAP_VERSION)) {
+			pr_warn("siw: received rdmap version unsupported %d\n",
+				__rdmap_get_version(c_hdr));
+
+			siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_RDMAP,
+					   RDMAP_ETYPE_REMOTE_OPERATION,
+					   RDMAP_ECODE_VERSION, 0);
+			return -EINVAL;
+		}
+		opcode = __rdmap_get_opcode(c_hdr);
+
+		if (opcode > RDMAP_TERMINATE) {
+			pr_warn("siw: received unknown packet type %u\n",
+				opcode);
+
+			siw_init_terminate(rx_qp(srx), TERM_ERROR_LAYER_RDMAP,
+					   RDMAP_ETYPE_REMOTE_OPERATION,
+					   RDMAP_ECODE_OPCODE, 0);
+			return -EINVAL;
+		}
+		siw_dbg_qp(rx_qp(srx), "new header, opcode %u\n", opcode);
+	} else {
+		opcode = __rdmap_get_opcode(c_hdr);
+	}
+	set_rx_fpdu_context(qp, opcode);
+	frx = qp->rx_fpdu;
+
+	/*
+	 * Figure out len of current hdr: variable length of
+	 * iwarp hdr may force us to copy hdr information in
+	 * two steps. Only tagged DDP messages are already
+	 * completely received.
+	 */
+	if (iwarp_pktinfo[opcode].hdr_len > sizeof(struct iwarp_ctrl_tagged)) {
+		bytes = iwarp_pktinfo[opcode].hdr_len - MIN_DDP_HDR;
+
+		if (srx->skb_new < bytes)
+			return -EAGAIN;
+
+		skb_copy_bits(skb, srx->skb_offset,
+			      (char *)c_hdr + srx->fpdu_part_rcvd, bytes);
+
+		srx->fpdu_part_rcvd += bytes;
+
+		srx->skb_new -= bytes;
+		srx->skb_offset += bytes;
+		srx->skb_copied += bytes;
+	}
+
+	/*
+	 * DDP/RDMAP header receive completed. Check if the current
+	 * DDP segment starts a new RDMAP message or continues a previously
+	 * started RDMAP message.
+	 *
+	 * Alternating reception of DDP segments (or FPDUs) from incomplete
+	 * tagged and untagged RDMAP messages is supported, as long as
+	 * the current tagged or untagged message gets eventually completed
+	 * w/o intersection from another message of the same type
+	 * (tagged/untagged). E.g., a WRITE can get intersected by a SEND,
+	 * but not by a READ RESPONSE etc.
+	 */
+	if (srx->mpa_crc_hd) {
+		/*
+		 * Restart CRC computation
+		 */
+		crypto_shash_init(srx->mpa_crc_hd);
+		crypto_shash_update(srx->mpa_crc_hd, (u8 *)c_hdr,
+				    srx->fpdu_part_rcvd);
+	}
+	if (frx->more_ddp_segs) {
+		frx->first_ddp_seg = 0;
+		if (frx->prev_rdmap_op != opcode) {
+			pr_warn("siw: packet intersection: %u : %u\n",
+				frx->prev_rdmap_op, opcode);
+			/*
+			 * The last inbound RDMA operation of same type
+			 * (tagged or untagged) is left unfinished.
+			 * To complete it in error, make it the current
+			 * operation again, even with the header already
+			 * overwritten. For error handling, only the opcode
+			 * and current rx context are relevant.
+			 */
+			set_rx_fpdu_context(qp, frx->prev_rdmap_op);
+			__rdmap_set_opcode(c_hdr, frx->prev_rdmap_op);
+			return -EPROTO;
+		}
+	} else {
+		frx->prev_rdmap_op = opcode;
+		frx->first_ddp_seg = 1;
+	}
+	frx->more_ddp_segs = c_hdr->ddp_rdmap_ctrl & DDP_FLAG_LAST ? 0 : 1;
+
+	return 0;
+}
+
+static int siw_check_tx_fence(struct siw_qp *qp)
+{
+	struct siw_wqe *tx_waiting = tx_wqe(qp);
+	struct siw_sqe *rreq;
+	int resume_tx = 0, rv = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&qp->orq_lock, flags);
+
+	rreq = orq_get_current(qp);
+
+	/* free current orq entry */
+	WRITE_ONCE(rreq->flags, 0);
+
+	if (qp->tx_ctx.orq_fence) {
+		if (unlikely(tx_waiting->wr_status != SIW_WR_QUEUED)) {
+			pr_warn("siw: [QP %u]: fence resume: bad status %d\n",
+				qp_id(qp), tx_waiting->wr_status);
+			rv = -EPROTO;
+			goto out;
+		}
+		/* resume SQ processing */
+		if (tx_waiting->sqe.opcode == SIW_OP_READ ||
+		    tx_waiting->sqe.opcode == SIW_OP_READ_LOCAL_INV) {
+			rreq = orq_get_tail(qp);
+			if (unlikely(!rreq)) {
+				pr_warn("siw: [QP %u]: no ORQE\n", qp_id(qp));
+				rv = -EPROTO;
+				goto out;
+			}
+			siw_read_to_orq(rreq, &tx_waiting->sqe);
+
+			qp->orq_put++;
+			qp->tx_ctx.orq_fence = 0;
+			resume_tx = 1;
+
+		} else if (siw_orq_empty(qp)) {
+			qp->tx_ctx.orq_fence = 0;
+			resume_tx = 1;
+		} else {
+			pr_warn("siw: [QP %u]: fence resume: orq idx: %d:%d\n",
+				qp_id(qp), qp->orq_get, qp->orq_put);
+			rv = -EPROTO;
+		}
+	}
+	qp->orq_get++;
+out:
+	spin_unlock_irqrestore(&qp->orq_lock, flags);
+
+	if (resume_tx)
+		rv = siw_sq_start(qp);
+
+	return rv;
+}
+
+/*
+ * siw_rdmap_complete()
+ *
+ * Complete processing of an RDMA message after receiving all
+ * DDP segmens or ABort processing after encountering error case.
+ *
+ *   o SENDs + RRESPs will need for completion,
+ *   o RREQs need for  READ RESPONSE initialization
+ *   o WRITEs need memory dereferencing
+ *
+ * TODO: Failed WRITEs need local error to be surfaced.
+ */
+static int siw_rdmap_complete(struct siw_qp *qp, int error)
+{
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	struct siw_wqe *wqe = rx_wqe(qp->rx_fpdu);
+	enum siw_wc_status wc_status = wqe->wc_status;
+	u8 opcode = __rdmap_get_opcode(&srx->hdr.ctrl);
+	int rv = 0;
+
+	switch (opcode) {
+	case RDMAP_SEND_SE:
+	case RDMAP_SEND_SE_INVAL:
+		wqe->rqe.flags |= SIW_WQE_SOLICITED;
+	case RDMAP_SEND:
+	case RDMAP_SEND_INVAL:
+		if (wqe->wr_status == SIW_WR_IDLE)
+			break;
+
+		srx->ddp_msn[RDMAP_UNTAGGED_QN_SEND]++;
+
+		if (error != 0 && wc_status == SIW_WC_SUCCESS)
+			wc_status = SIW_WC_GENERAL_ERR;
+		/*
+		 * Handle STag invalidation request
+		 */
+		if (wc_status == SIW_WC_SUCCESS &&
+		    (opcode == RDMAP_SEND_INVAL ||
+		     opcode == RDMAP_SEND_SE_INVAL)) {
+			rv = siw_invalidate_stag(qp->pd, srx->inval_stag);
+			if (rv) {
+				siw_init_terminate(
+					qp, TERM_ERROR_LAYER_RDMAP,
+					rv == -EACCES ?
+						RDMAP_ETYPE_REMOTE_PROTECTION :
+						RDMAP_ETYPE_REMOTE_OPERATION,
+					RDMAP_ECODE_CANNOT_INVALIDATE, 0);
+
+				wc_status = SIW_WC_REM_INV_REQ_ERR;
+			}
+			rv = siw_rqe_complete(qp, &wqe->rqe, wqe->processed,
+					      rv ? 0 : srx->inval_stag,
+					      wc_status);
+		} else {
+			rv = siw_rqe_complete(qp, &wqe->rqe, wqe->processed,
+					      0, wc_status);
+		}
+		siw_wqe_put_mem(wqe, SIW_OP_RECEIVE);
+		break;
+
+	case RDMAP_RDMA_READ_RESP:
+		if (wqe->wr_status == SIW_WR_IDLE)
+			break;
+
+		if (error != 0) {
+			if ((srx->state == SIW_GET_HDR &&
+			     qp->rx_fpdu->first_ddp_seg) || error == -ENODATA)
+				/* possible RREQ in ORQ left untouched */
+				break;
+
+			if (wc_status == SIW_WC_SUCCESS)
+				wc_status = SIW_WC_GENERAL_ERR;
+		} else if (qp->kernel_verbs &&
+			   rx_type(wqe) == SIW_OP_READ_LOCAL_INV) {
+			/*
+			 * Handle any STag invalidation request
+			 */
+			rv = siw_invalidate_stag(qp->pd, wqe->sqe.sge[0].lkey);
+			if (rv) {
+				siw_init_terminate(qp, TERM_ERROR_LAYER_RDMAP,
+						   RDMAP_ETYPE_CATASTROPHIC,
+						   RDMAP_ECODE_UNSPECIFIED, 0);
+
+				if (wc_status == SIW_WC_SUCCESS) {
+					wc_status = SIW_WC_GENERAL_ERR;
+					error = rv;
+				}
+			}
+		}
+		/*
+		 * All errors turn the wqe into signalled.
+		 */
+		if ((wqe->sqe.flags & SIW_WQE_SIGNALLED) || error != 0)
+			rv = siw_sqe_complete(qp, &wqe->sqe, wqe->processed,
+					      wc_status);
+		siw_wqe_put_mem(wqe, SIW_OP_READ);
+
+		if (!error)
+			rv = siw_check_tx_fence(qp);
+		else
+			/* Disable current ORQ eleement */
+			WRITE_ONCE(orq_get_current(qp)->flags, 0);
+		break;
+
+	case RDMAP_RDMA_READ_REQ:
+		if (!error) {
+			rv = siw_init_rresp(qp, srx);
+			srx->ddp_msn[RDMAP_UNTAGGED_QN_RDMA_READ]++;
+		}
+		break;
+
+	case RDMAP_RDMA_WRITE:
+		if (wqe->wr_status == SIW_WR_IDLE)
+			break;
+
+		/*
+		 * Free References from memory object if
+		 * attached to receive context (inbound WRITE).
+		 * While a zero-length WRITE is allowed,
+		 * no memory reference got created.
+		 */
+		if (rx_mem(&qp->rx_tagged)) {
+			siw_mem_put(rx_mem(&qp->rx_tagged));
+			rx_mem(&qp->rx_tagged) = NULL;
+		}
+		break;
+
+	default:
+		break;
+	}
+	wqe->wr_status = SIW_WR_IDLE;
+
+	return rv;
+}
+
+/*
+ * siw_tcp_rx_data()
+ *
+ * Main routine to consume inbound TCP payload
+ *
+ * @rd_desc:	read descriptor
+ * @skb:	socket buffer
+ * @off:	offset in skb
+ * @len:	skb->len - offset : payload in skb
+ */
+int siw_tcp_rx_data(read_descriptor_t *rd_desc, struct sk_buff *skb,
+		    unsigned int off, size_t len)
+{
+	struct siw_qp *qp = rd_desc->arg.data;
+	struct siw_rx_stream *srx = &qp->rx_stream;
+	int rv;
+
+	srx->skb = skb;
+	srx->skb_new = skb->len - off;
+	srx->skb_offset = off;
+	srx->skb_copied = 0;
+
+	siw_dbg_qp(qp, "new data, len %d\n", srx->skb_new);
+
+	while (srx->skb_new) {
+		int run_completion = 1;
+
+		if (unlikely(srx->rx_suspend)) {
+			/* Do not process any more data */
+			srx->skb_copied += srx->skb_new;
+			break;
+		}
+		switch (srx->state) {
+		case SIW_GET_HDR:
+			rv = siw_get_hdr(srx);
+			if (!rv) {
+				srx->fpdu_part_rem =
+					be16_to_cpu(srx->hdr.ctrl.mpa_len) -
+					srx->fpdu_part_rcvd + MPA_HDR_SIZE;
+
+				if (srx->fpdu_part_rem)
+					srx->pad = -srx->fpdu_part_rem & 0x3;
+				else
+					srx->pad = 0;
+
+				srx->state = SIW_GET_DATA_START;
+				srx->fpdu_part_rcvd = 0;
+			}
+			break;
+
+		case SIW_GET_DATA_MORE:
+			/*
+			 * Another data fragment of the same DDP segment.
+			 * Setting first_ddp_seg = 0 avoids repeating
+			 * initializations that shall occur only once per
+			 * DDP segment.
+			 */
+			qp->rx_fpdu->first_ddp_seg = 0;
+			/* Fall through */
+
+		case SIW_GET_DATA_START:
+			/*
+			 * Headers will be checked by the opcode-specific
+			 * data receive function below.
+			 */
+			rv = iwarp_pktinfo[qp->rx_stream.rdmap_op].rx_data(qp);
+			if (!rv) {
+				int mpa_len =
+					be16_to_cpu(srx->hdr.ctrl.mpa_len)
+					+ MPA_HDR_SIZE;
+
+				srx->fpdu_part_rem = (-mpa_len & 0x3)
+						      + MPA_CRC_SIZE;
+				srx->fpdu_part_rcvd = 0;
+				srx->state = SIW_GET_TRAILER;
+			} else {
+				if (unlikely(rv == -ECONNRESET))
+					run_completion = 0;
+				else
+					srx->state = SIW_GET_DATA_MORE;
+			}
+			break;
+
+		case SIW_GET_TRAILER:
+			/*
+			 * read CRC + any padding
+			 */
+			rv = siw_get_trailer(qp, srx);
+			if (likely(!rv)) {
+				/*
+				 * FPDU completed.
+				 * complete RDMAP message if last fragment
+				 */
+				srx->state = SIW_GET_HDR;
+				srx->fpdu_part_rcvd = 0;
+
+				if (!(srx->hdr.ctrl.ddp_rdmap_ctrl &
+				      DDP_FLAG_LAST))
+					/* more frags */
+					break;
+
+				rv = siw_rdmap_complete(qp, 0);
+				run_completion = 0;
+			}
+			break;
+
+		default:
+			pr_warn("QP[%u]: RX out of state\n", qp_id(qp));
+			rv = -EPROTO;
+			run_completion = 0;
+		}
+		if (unlikely(rv != 0 && rv != -EAGAIN)) {
+			if ((srx->state > SIW_GET_HDR ||
+			     qp->rx_fpdu->more_ddp_segs) && run_completion)
+				siw_rdmap_complete(qp, rv);
+
+			siw_dbg_qp(qp, "rx error %d, rx state %d\n", rv,
+				   srx->state);
+
+			siw_qp_cm_drop(qp, 1);
+
+			break;
+		}
+		if (rv) {
+			siw_dbg_qp(qp, "fpdu fragment, state %d, missing %d\n",
+				   srx->state, srx->fpdu_part_rem);
+			break;
+		}
+	}
+	return srx->skb_copied;
+}