rdma/siw: completion queue methods

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_cq.c

@@ -0,0 +1,101 @@
+// 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 <rdma/ib_verbs.h>
+
+#include "siw.h"
+
+static int map_wc_opcode[SIW_NUM_OPCODES] = {
+	[SIW_OP_WRITE] = IB_WC_RDMA_WRITE,
+	[SIW_OP_SEND] = IB_WC_SEND,
+	[SIW_OP_SEND_WITH_IMM] = IB_WC_SEND,
+	[SIW_OP_READ] = IB_WC_RDMA_READ,
+	[SIW_OP_READ_LOCAL_INV] = IB_WC_RDMA_READ,
+	[SIW_OP_COMP_AND_SWAP] = IB_WC_COMP_SWAP,
+	[SIW_OP_FETCH_AND_ADD] = IB_WC_FETCH_ADD,
+	[SIW_OP_INVAL_STAG] = IB_WC_LOCAL_INV,
+	[SIW_OP_REG_MR] = IB_WC_REG_MR,
+	[SIW_OP_RECEIVE] = IB_WC_RECV,
+	[SIW_OP_READ_RESPONSE] = -1 /* not used */
+};
+
+static struct {
+	enum siw_opcode siw;
+	enum ib_wc_status ib;
+} map_cqe_status[SIW_NUM_WC_STATUS] = {
+	{ SIW_WC_SUCCESS, IB_WC_SUCCESS },
+	{ SIW_WC_LOC_LEN_ERR, IB_WC_LOC_LEN_ERR },
+	{ SIW_WC_LOC_PROT_ERR, IB_WC_LOC_PROT_ERR },
+	{ SIW_WC_LOC_QP_OP_ERR, IB_WC_LOC_QP_OP_ERR },
+	{ SIW_WC_WR_FLUSH_ERR, IB_WC_WR_FLUSH_ERR },
+	{ SIW_WC_BAD_RESP_ERR, IB_WC_BAD_RESP_ERR },
+	{ SIW_WC_LOC_ACCESS_ERR, IB_WC_LOC_ACCESS_ERR },
+	{ SIW_WC_REM_ACCESS_ERR, IB_WC_REM_ACCESS_ERR },
+	{ SIW_WC_REM_INV_REQ_ERR, IB_WC_REM_INV_REQ_ERR },
+	{ SIW_WC_GENERAL_ERR, IB_WC_GENERAL_ERR }
+};
+
+/*
+ * Reap one CQE from the CQ. Only used by kernel clients
+ * during CQ normal operation. Might be called during CQ
+ * flush for user mapped CQE array as well.
+ */
+int siw_reap_cqe(struct siw_cq *cq, struct ib_wc *wc)
+{
+	struct siw_cqe *cqe;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cq->lock, flags);
+
+	cqe = &cq->queue[cq->cq_get % cq->num_cqe];
+	if (READ_ONCE(cqe->flags) & SIW_WQE_VALID) {
+		memset(wc, 0, sizeof(*wc));
+		wc->wr_id = cqe->id;
+		wc->status = map_cqe_status[cqe->status].ib;
+		wc->opcode = map_wc_opcode[cqe->opcode];
+		wc->byte_len = cqe->bytes;
+
+		/*
+		 * During CQ flush, also user land CQE's may get
+		 * reaped here, which do not hold a QP reference
+		 * and do not qualify for memory extension verbs.
+		 */
+		if (likely(cq->kernel_verbs)) {
+			if (cqe->flags & SIW_WQE_REM_INVAL) {
+				wc->ex.invalidate_rkey = cqe->inval_stag;
+				wc->wc_flags = IB_WC_WITH_INVALIDATE;
+			}
+			wc->qp = cqe->base_qp;
+			siw_dbg_cq(cq, "idx %u, type %d, flags %2x, id 0x%p\n",
+				   cq->cq_get % cq->num_cqe, cqe->opcode,
+				   cqe->flags, (void *)cqe->id);
+		}
+		WRITE_ONCE(cqe->flags, 0);
+		cq->cq_get++;
+
+		spin_unlock_irqrestore(&cq->lock, flags);
+
+		return 1;
+	}
+	spin_unlock_irqrestore(&cq->lock, flags);
+
+	return 0;
+}
+
+/*
+ * siw_cq_flush()
+ *
+ * Flush all CQ elements.
+ */
+void siw_cq_flush(struct siw_cq *cq)
+{
+	struct ib_wc wc;
+
+	while (siw_reap_cqe(cq, &wc))
+		;
+}