drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c - linux - Git at Google

 /*
  * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of EITHER the GNU General Public License
  * version 2 as published by the Free Software Foundation or the BSD
  * 2-Clause License. This program is distributed in the hope that it
  * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  * See the GNU General Public License version 2 for more details at
  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program available in the file COPYING in the main
  * directory of this source tree.
  *
  * The BSD 2-Clause License
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <asm/page.h>
 #include <linux/io.h>
 #include <linux/wait.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib_smi.h>
 #include <rdma/ib_user_verbs.h>
 #include <rdma/uverbs_ioctl.h>

 #include "pvrdma.h"

 /**
  * pvrdma_req_notify_cq - request notification for a completion queue
  * @ibcq: the completion queue
  * @notify_flags: notification flags
  *
  * @return: 0 for success.
  */
 int pvrdma_req_notify_cq(struct ib_cq *ibcq,
 			 enum ib_cq_notify_flags notify_flags)
 {
 	struct pvrdma_dev *dev = to_vdev(ibcq->device);
 	struct pvrdma_cq *cq = to_vcq(ibcq);
 	u32 val = cq->cq_handle;
 	unsigned long flags;
 	int has_data = 0;

 	val |= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
 		PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;

 	spin_lock_irqsave(&cq->cq_lock, flags);

 	pvrdma_write_uar_cq(dev, val);

 	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
 		unsigned int head;

 		has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
 						    cq->ibcq.cqe, &head);
 		if (unlikely(has_data == PVRDMA_INVALID_IDX))
 			dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
 	}

 	spin_unlock_irqrestore(&cq->cq_lock, flags);

 	return has_data;
 }

 /**
  * pvrdma_create_cq - create completion queue
  * @ibcq: Allocated CQ
  * @attr: completion queue attributes
  * @udata: user data
  *
  * @return: 0 on success
  */
 int pvrdma_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
 		     struct ib_udata *udata)
 {
 	struct ib_device *ibdev = ibcq->device;
 	int entries = attr->cqe;
 	struct pvrdma_dev *dev = to_vdev(ibdev);
 	struct pvrdma_cq *cq = to_vcq(ibcq);
 	int ret;
 	int npages;
 	unsigned long flags;
 	union pvrdma_cmd_req req;
 	union pvrdma_cmd_resp rsp;
 	struct pvrdma_cmd_create_cq *cmd = &req.create_cq;
 	struct pvrdma_cmd_create_cq_resp *resp = &rsp.create_cq_resp;
 	struct pvrdma_create_cq_resp cq_resp = {};
 	struct pvrdma_create_cq ucmd;
 	struct pvrdma_ucontext *context = rdma_udata_to_drv_context(
 		udata, struct pvrdma_ucontext, ibucontext);

 	BUILD_BUG_ON(sizeof(struct pvrdma_cqe) != 64);

 	if (attr->flags)
 		return -EOPNOTSUPP;

 	entries = roundup_pow_of_two(entries);
 	if (entries < 1 || entries > dev->dsr->caps.max_cqe)
 		return -EINVAL;

 	if (!atomic_add_unless(&dev->num_cqs, 1, dev->dsr->caps.max_cq))
 		return -ENOMEM;

 	cq->ibcq.cqe = entries;
 	cq->is_kernel = !udata;

 	if (!cq->is_kernel) {
 		if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd))) {
 			ret = -EFAULT;
 			goto err_cq;
 		}

 		cq->umem = ib_umem_get(ibdev, ucmd.buf_addr, ucmd.buf_size,
 				       IB_ACCESS_LOCAL_WRITE);
 		if (IS_ERR(cq->umem)) {
 			ret = PTR_ERR(cq->umem);
 			goto err_cq;
 		}

 		npages = ib_umem_num_dma_blocks(cq->umem, PAGE_SIZE);
 	} else {
 		/* One extra page for shared ring state */
 		npages = 1 + (entries * sizeof(struct pvrdma_cqe) +
 			      PAGE_SIZE - 1) / PAGE_SIZE;

 		/* Skip header page. */
 		cq->offset = PAGE_SIZE;
 	}

 	if (npages < 0 || npages > PVRDMA_PAGE_DIR_MAX_PAGES) {
 		dev_warn(&dev->pdev->dev,
 			 "overflow pages in completion queue\n");
 		ret = -EINVAL;
 		goto err_umem;
 	}

 	ret = pvrdma_page_dir_init(dev, &cq->pdir, npages, cq->is_kernel);
 	if (ret) {
 		dev_warn(&dev->pdev->dev,
 			 "could not allocate page directory\n");
 		goto err_umem;
 	}

 	/* Ring state is always the first page. Set in library for user cq. */
 	if (cq->is_kernel)
 		cq->ring_state = cq->pdir.pages[0];
 	else
 		pvrdma_page_dir_insert_umem(&cq->pdir, cq->umem, 0);

 	refcount_set(&cq->refcnt, 1);
 	init_completion(&cq->free);
 	spin_lock_init(&cq->cq_lock);

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_CREATE_CQ;
 	cmd->nchunks = npages;
 	cmd->ctx_handle = context ? context->ctx_handle : 0;
 	cmd->cqe = entries;
 	cmd->pdir_dma = cq->pdir.dir_dma;
 	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_CQ_RESP);
 	if (ret < 0) {
 		dev_warn(&dev->pdev->dev,
 			 "could not create completion queue, error: %d\n", ret);
 		goto err_page_dir;
 	}

 	cq->ibcq.cqe = resp->cqe;
 	cq->cq_handle = resp->cq_handle;
 	cq_resp.cqn = resp->cq_handle;
 	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
 	dev->cq_tbl[cq->cq_handle % dev->dsr->caps.max_cq] = cq;
 	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

 	if (!cq->is_kernel) {
 		cq->uar = &context->uar;

 		/* Copy udata back. */
 		if (ib_copy_to_udata(udata, &cq_resp, sizeof(cq_resp))) {
 			dev_warn(&dev->pdev->dev,
 				 "failed to copy back udata\n");
 			pvrdma_destroy_cq(&cq->ibcq, udata);
 			return -EINVAL;
 		}
 	}

 	return 0;

 err_page_dir:
 	pvrdma_page_dir_cleanup(dev, &cq->pdir);
 err_umem:
 	ib_umem_release(cq->umem);
 err_cq:
 	atomic_dec(&dev->num_cqs);
 	return ret;
 }

 static void pvrdma_free_cq(struct pvrdma_dev *dev, struct pvrdma_cq *cq)
 {
 	if (refcount_dec_and_test(&cq->refcnt))
 		complete(&cq->free);
 	wait_for_completion(&cq->free);

 	ib_umem_release(cq->umem);

 	pvrdma_page_dir_cleanup(dev, &cq->pdir);
 }

 /**
  * pvrdma_destroy_cq - destroy completion queue
  * @cq: the completion queue to destroy.
  * @udata: user data or null for kernel object
  */
 int pvrdma_destroy_cq(struct ib_cq *cq, struct ib_udata *udata)
 {
 	struct pvrdma_cq *vcq = to_vcq(cq);
 	union pvrdma_cmd_req req;
 	struct pvrdma_cmd_destroy_cq *cmd = &req.destroy_cq;
 	struct pvrdma_dev *dev = to_vdev(cq->device);
 	unsigned long flags;
 	int ret;

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_CQ;
 	cmd->cq_handle = vcq->cq_handle;

 	ret = pvrdma_cmd_post(dev, &req, NULL, 0);
 	if (ret < 0)
 		dev_warn(&dev->pdev->dev,
 			 "could not destroy completion queue, error: %d\n",
 			 ret);

 	/* free cq's resources */
 	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
 	dev->cq_tbl[vcq->cq_handle] = NULL;
 	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

 	pvrdma_free_cq(dev, vcq);
 	atomic_dec(&dev->num_cqs);
 	return 0;
 }

 static inline struct pvrdma_cqe *get_cqe(struct pvrdma_cq *cq, int i)
 {
 	return (struct pvrdma_cqe *)pvrdma_page_dir_get_ptr(
 					&cq->pdir,
 					cq->offset +
 					sizeof(struct pvrdma_cqe) * i);
 }

 void _pvrdma_flush_cqe(struct pvrdma_qp *qp, struct pvrdma_cq *cq)
 {
 	unsigned int head;
 	int has_data;

 	if (!cq->is_kernel)
 		return;

 	/* Lock held */
 	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
 					    cq->ibcq.cqe, &head);
 	if (unlikely(has_data > 0)) {
 		int items;
 		int curr;
 		int tail = pvrdma_idx(&cq->ring_state->rx.prod_tail,
 				      cq->ibcq.cqe);
 		struct pvrdma_cqe *cqe;
 		struct pvrdma_cqe *curr_cqe;

 		items = (tail > head) ? (tail - head) :
 			(cq->ibcq.cqe - head + tail);
 		curr = --tail;
 		while (items-- > 0) {
 			if (curr < 0)
 				curr = cq->ibcq.cqe - 1;
 			if (tail < 0)
 				tail = cq->ibcq.cqe - 1;
 			curr_cqe = get_cqe(cq, curr);
 			if ((curr_cqe->qp & 0xFFFF) != qp->qp_handle) {
 				if (curr != tail) {
 					cqe = get_cqe(cq, tail);
 					*cqe = *curr_cqe;
 				}
 				tail--;
 			} else {
 				pvrdma_idx_ring_inc(
 					&cq->ring_state->rx.cons_head,
 					cq->ibcq.cqe);
 			}
 			curr--;
 		}
 	}
 }

 static int pvrdma_poll_one(struct pvrdma_cq *cq, struct pvrdma_qp **cur_qp,
 			   struct ib_wc *wc)
 {
 	struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
 	int has_data;
 	unsigned int head;
 	bool tried = false;
 	struct pvrdma_cqe *cqe;

 retry:
 	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
 					    cq->ibcq.cqe, &head);
 	if (has_data == 0) {
 		if (tried)
 			return -EAGAIN;

 		pvrdma_write_uar_cq(dev, cq->cq_handle | PVRDMA_UAR_CQ_POLL);

 		tried = true;
 		goto retry;
 	} else if (has_data == PVRDMA_INVALID_IDX) {
 		dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
 		return -EAGAIN;
 	}

 	cqe = get_cqe(cq, head);

 	/* Ensure cqe is valid. */
 	rmb();
 	if (dev->qp_tbl[cqe->qp & 0xffff])
 		*cur_qp = (struct pvrdma_qp *)dev->qp_tbl[cqe->qp & 0xffff];
 	else
 		return -EAGAIN;

 	wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
 	wc->status = pvrdma_wc_status_to_ib(cqe->status);
 	wc->wr_id = cqe->wr_id;
 	wc->qp = &(*cur_qp)->ibqp;
 	wc->byte_len = cqe->byte_len;
 	wc->ex.imm_data = cqe->imm_data;
 	wc->src_qp = cqe->src_qp;
 	wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
 	wc->pkey_index = cqe->pkey_index;
 	wc->slid = cqe->slid;
 	wc->sl = cqe->sl;
 	wc->dlid_path_bits = cqe->dlid_path_bits;
 	wc->port_num = cqe->port_num;
 	wc->vendor_err = cqe->vendor_err;
 	wc->network_hdr_type = pvrdma_network_type_to_ib(cqe->network_hdr_type);

 	/* Update shared ring state */
 	pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);

 	return 0;
 }

 /**
  * pvrdma_poll_cq - poll for work completion queue entries
  * @ibcq: completion queue
  * @num_entries: the maximum number of entries
  * @wc: pointer to work completion array
  *
  * @return: number of polled completion entries
  */
 int pvrdma_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
 {
 	struct pvrdma_cq *cq = to_vcq(ibcq);
 	struct pvrdma_qp *cur_qp = NULL;
 	unsigned long flags;
 	int npolled;

 	if (num_entries < 1 || wc == NULL)
 		return 0;

 	spin_lock_irqsave(&cq->cq_lock, flags);
 	for (npolled = 0; npolled < num_entries; ++npolled) {
 		if (pvrdma_poll_one(cq, &cur_qp, wc + npolled))
 			break;
 	}

 	spin_unlock_irqrestore(&cq->cq_lock, flags);

 	/* Ensure we do not return errors from poll_cq */
 	return npolled;
 }
	/*
	* Copyright (c) 2012-2016 VMware, Inc. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of EITHER the GNU General Public License
	* version 2 as published by the Free Software Foundation or the BSD
	* 2-Clause License. This program is distributed in the hope that it
	* will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
	* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	* See the GNU General Public License version 2 for more details at
	* http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program available in the file COPYING in the main
	* directory of this source tree.
	*
	* The BSD 2-Clause License
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above
	* copyright notice, this list of conditions and the following
	* disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials
	* provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
	* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
	* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	* OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <asm/page.h>
	#include <linux/io.h>
	#include <linux/wait.h>
	#include <rdma/ib_addr.h>
	#include <rdma/ib_smi.h>
	#include <rdma/ib_user_verbs.h>
	#include <rdma/uverbs_ioctl.h>

	#include "pvrdma.h"

	/**
	* pvrdma_req_notify_cq - request notification for a completion queue
	* @ibcq: the completion queue
	* @notify_flags: notification flags
	*
	* @return: 0 for success.
	*/
	int pvrdma_req_notify_cq(struct ib_cq *ibcq,
	enum ib_cq_notify_flags notify_flags)
	{
	struct pvrdma_dev *dev = to_vdev(ibcq->device);
	struct pvrdma_cq *cq = to_vcq(ibcq);
	u32 val = cq->cq_handle;
	unsigned long flags;
	int has_data = 0;

	val \|= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
	PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;

	spin_lock_irqsave(&cq->cq_lock, flags);

	pvrdma_write_uar_cq(dev, val);

	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
	unsigned int head;

	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
	cq->ibcq.cqe, &head);
	if (unlikely(has_data == PVRDMA_INVALID_IDX))
	dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
	}

	spin_unlock_irqrestore(&cq->cq_lock, flags);

	return has_data;
	}

	/**
	* pvrdma_create_cq - create completion queue
	* @ibcq: Allocated CQ
	* @attr: completion queue attributes
	* @udata: user data
	*
	* @return: 0 on success
	*/
	int pvrdma_create_cq(struct ib_cq ibcq, const struct ib_cq_init_attr attr,
	struct ib_udata *udata)
	{
	struct ib_device *ibdev = ibcq->device;
	int entries = attr->cqe;
	struct pvrdma_dev *dev = to_vdev(ibdev);
	struct pvrdma_cq *cq = to_vcq(ibcq);
	int ret;
	int npages;
	unsigned long flags;
	union pvrdma_cmd_req req;
	union pvrdma_cmd_resp rsp;
	struct pvrdma_cmd_create_cq *cmd = &req.create_cq;
	struct pvrdma_cmd_create_cq_resp *resp = &rsp.create_cq_resp;
	struct pvrdma_create_cq_resp cq_resp = {};
	struct pvrdma_create_cq ucmd;
	struct pvrdma_ucontext *context = rdma_udata_to_drv_context(
	udata, struct pvrdma_ucontext, ibucontext);

	BUILD_BUG_ON(sizeof(struct pvrdma_cqe) != 64);

	if (attr->flags)
	return -EOPNOTSUPP;

	entries = roundup_pow_of_two(entries);
	if (entries < 1 \|\| entries > dev->dsr->caps.max_cqe)
	return -EINVAL;

	if (!atomic_add_unless(&dev->num_cqs, 1, dev->dsr->caps.max_cq))
	return -ENOMEM;

	cq->ibcq.cqe = entries;
	cq->is_kernel = !udata;

	if (!cq->is_kernel) {
	if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd))) {
	ret = -EFAULT;
	goto err_cq;
	}

	cq->umem = ib_umem_get(ibdev, ucmd.buf_addr, ucmd.buf_size,
	IB_ACCESS_LOCAL_WRITE);
	if (IS_ERR(cq->umem)) {
	ret = PTR_ERR(cq->umem);
	goto err_cq;
	}

	npages = ib_umem_num_dma_blocks(cq->umem, PAGE_SIZE);
	} else {
	/* One extra page for shared ring state */
	npages = 1 + (entries * sizeof(struct pvrdma_cqe) +
	PAGE_SIZE - 1) / PAGE_SIZE;

	/* Skip header page. */
	cq->offset = PAGE_SIZE;
	}

	if (npages < 0 \|\| npages > PVRDMA_PAGE_DIR_MAX_PAGES) {
	dev_warn(&dev->pdev->dev,
	"overflow pages in completion queue\n");
	ret = -EINVAL;
	goto err_umem;
	}

	ret = pvrdma_page_dir_init(dev, &cq->pdir, npages, cq->is_kernel);
	if (ret) {
	dev_warn(&dev->pdev->dev,
	"could not allocate page directory\n");
	goto err_umem;
	}

	/* Ring state is always the first page. Set in library for user cq. */
	if (cq->is_kernel)
	cq->ring_state = cq->pdir.pages[0];
	else
	pvrdma_page_dir_insert_umem(&cq->pdir, cq->umem, 0);

	refcount_set(&cq->refcnt, 1);
	init_completion(&cq->free);
	spin_lock_init(&cq->cq_lock);

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_CREATE_CQ;
	cmd->nchunks = npages;
	cmd->ctx_handle = context ? context->ctx_handle : 0;
	cmd->cqe = entries;
	cmd->pdir_dma = cq->pdir.dir_dma;
	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_CQ_RESP);
	if (ret < 0) {
	dev_warn(&dev->pdev->dev,
	"could not create completion queue, error: %d\n", ret);
	goto err_page_dir;
	}

	cq->ibcq.cqe = resp->cqe;
	cq->cq_handle = resp->cq_handle;
	cq_resp.cqn = resp->cq_handle;
	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
	dev->cq_tbl[cq->cq_handle % dev->dsr->caps.max_cq] = cq;
	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

	if (!cq->is_kernel) {
	cq->uar = &context->uar;

	/* Copy udata back. */
	if (ib_copy_to_udata(udata, &cq_resp, sizeof(cq_resp))) {
	dev_warn(&dev->pdev->dev,
	"failed to copy back udata\n");
	pvrdma_destroy_cq(&cq->ibcq, udata);
	return -EINVAL;
	}
	}

	return 0;

	err_page_dir:
	pvrdma_page_dir_cleanup(dev, &cq->pdir);
	err_umem:
	ib_umem_release(cq->umem);
	err_cq:
	atomic_dec(&dev->num_cqs);
	return ret;
	}

	static void pvrdma_free_cq(struct pvrdma_dev dev, struct pvrdma_cq cq)
	{
	if (refcount_dec_and_test(&cq->refcnt))
	complete(&cq->free);
	wait_for_completion(&cq->free);

	ib_umem_release(cq->umem);

	pvrdma_page_dir_cleanup(dev, &cq->pdir);
	}

	/**
	* pvrdma_destroy_cq - destroy completion queue
	* @cq: the completion queue to destroy.
	* @udata: user data or null for kernel object
	*/
	int pvrdma_destroy_cq(struct ib_cq cq, struct ib_udata udata)
	{
	struct pvrdma_cq *vcq = to_vcq(cq);
	union pvrdma_cmd_req req;
	struct pvrdma_cmd_destroy_cq *cmd = &req.destroy_cq;
	struct pvrdma_dev *dev = to_vdev(cq->device);
	unsigned long flags;
	int ret;

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_CQ;
	cmd->cq_handle = vcq->cq_handle;

	ret = pvrdma_cmd_post(dev, &req, NULL, 0);
	if (ret < 0)
	dev_warn(&dev->pdev->dev,
	"could not destroy completion queue, error: %d\n",
	ret);

	/* free cq's resources */
	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
	dev->cq_tbl[vcq->cq_handle] = NULL;
	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);

	pvrdma_free_cq(dev, vcq);
	atomic_dec(&dev->num_cqs);
	return 0;
	}

	static inline struct pvrdma_cqe get_cqe(struct pvrdma_cq cq, int i)
	{
	return (struct pvrdma_cqe *)pvrdma_page_dir_get_ptr(
	&cq->pdir,
	cq->offset +
	sizeof(struct pvrdma_cqe) * i);
	}

	void _pvrdma_flush_cqe(struct pvrdma_qp qp, struct pvrdma_cq cq)
	{
	unsigned int head;
	int has_data;

	if (!cq->is_kernel)
	return;

	/* Lock held */
	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
	cq->ibcq.cqe, &head);
	if (unlikely(has_data > 0)) {
	int items;
	int curr;
	int tail = pvrdma_idx(&cq->ring_state->rx.prod_tail,
	cq->ibcq.cqe);
	struct pvrdma_cqe *cqe;
	struct pvrdma_cqe *curr_cqe;

	items = (tail > head) ? (tail - head) :
	(cq->ibcq.cqe - head + tail);
	curr = --tail;
	while (items-- > 0) {
	if (curr < 0)
	curr = cq->ibcq.cqe - 1;
	if (tail < 0)
	tail = cq->ibcq.cqe - 1;
	curr_cqe = get_cqe(cq, curr);
	if ((curr_cqe->qp & 0xFFFF) != qp->qp_handle) {
	if (curr != tail) {
	cqe = get_cqe(cq, tail);
	cqe = curr_cqe;
	}
	tail--;
	} else {
	pvrdma_idx_ring_inc(
	&cq->ring_state->rx.cons_head,
	cq->ibcq.cqe);
	}
	curr--;
	}
	}
	}

	static int pvrdma_poll_one(struct pvrdma_cq cq, struct pvrdma_qp *cur_qp,
	struct ib_wc *wc)
	{
	struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
	int has_data;
	unsigned int head;
	bool tried = false;
	struct pvrdma_cqe *cqe;

	retry:
	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
	cq->ibcq.cqe, &head);
	if (has_data == 0) {
	if (tried)
	return -EAGAIN;

	pvrdma_write_uar_cq(dev, cq->cq_handle \| PVRDMA_UAR_CQ_POLL);

	tried = true;
	goto retry;
	} else if (has_data == PVRDMA_INVALID_IDX) {
	dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
	return -EAGAIN;
	}

	cqe = get_cqe(cq, head);

	/* Ensure cqe is valid. */
	rmb();
	if (dev->qp_tbl[cqe->qp & 0xffff])
	cur_qp = (struct pvrdma_qp )dev->qp_tbl[cqe->qp & 0xffff];
	else
	return -EAGAIN;

	wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
	wc->status = pvrdma_wc_status_to_ib(cqe->status);
	wc->wr_id = cqe->wr_id;
	wc->qp = &(*cur_qp)->ibqp;
	wc->byte_len = cqe->byte_len;
	wc->ex.imm_data = cqe->imm_data;
	wc->src_qp = cqe->src_qp;
	wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
	wc->pkey_index = cqe->pkey_index;
	wc->slid = cqe->slid;
	wc->sl = cqe->sl;
	wc->dlid_path_bits = cqe->dlid_path_bits;
	wc->port_num = cqe->port_num;
	wc->vendor_err = cqe->vendor_err;
	wc->network_hdr_type = pvrdma_network_type_to_ib(cqe->network_hdr_type);

	/* Update shared ring state */
	pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);

	return 0;
	}

	/**
	* pvrdma_poll_cq - poll for work completion queue entries
	* @ibcq: completion queue
	* @num_entries: the maximum number of entries
	* @wc: pointer to work completion array
	*
	* @return: number of polled completion entries
	*/
	int pvrdma_poll_cq(struct ib_cq ibcq, int num_entries, struct ib_wc wc)
	{
	struct pvrdma_cq *cq = to_vcq(ibcq);
	struct pvrdma_qp *cur_qp = NULL;
	unsigned long flags;
	int npolled;

	if (num_entries < 1 \|\| wc == NULL)
	return 0;

	spin_lock_irqsave(&cq->cq_lock, flags);
	for (npolled = 0; npolled < num_entries; ++npolled) {
	if (pvrdma_poll_one(cq, &cur_qp, wc + npolled))
	break;
	}

	spin_unlock_irqrestore(&cq->cq_lock, flags);

	/* Ensure we do not return errors from poll_cq */
	return npolled;
	}