drivers/infiniband/sw/rdmavt/cq.c - third_party/kernel - Git at Google

 /*
  * Copyright(c) 2016 - 2018 Intel Corporation.
  *
  * This file is provided under a dual BSD/GPLv2 license.  When using or
  * redistributing this file, you may do so under either license.
  *
  * GPL LICENSE SUMMARY
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
  * published by the Free Software Foundation.
  *
  * 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 for more details.
  *
  * BSD 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.
  *  - Neither the name of Intel Corporation nor the names of its
  *    contributors may be used to endorse or promote products derived
  *    from this software without specific prior written permission.
  *
  * 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
  * OWNER 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 <linux/slab.h>
 #include <linux/vmalloc.h>
 #include "cq.h"
 #include "vt.h"
 #include "trace.h"

 static struct workqueue_struct *comp_vector_wq;

 /**
  * rvt_cq_enter - add a new entry to the completion queue
  * @cq: completion queue
  * @entry: work completion entry to add
  * @solicited: true if @entry is solicited
  *
  * This may be called with qp->s_lock held.
  *
  * Return: return true on success, else return
  * false if cq is full.
  */
 bool rvt_cq_enter(struct rvt_cq *cq, struct ib_wc *entry, bool solicited)
 {
 	struct ib_uverbs_wc *uqueue = NULL;
 	struct ib_wc *kqueue = NULL;
 	struct rvt_cq_wc *u_wc = NULL;
 	struct rvt_k_cq_wc *k_wc = NULL;
 	unsigned long flags;
 	u32 head;
 	u32 next;
 	u32 tail;

 	spin_lock_irqsave(&cq->lock, flags);

 	if (cq->ip) {
 		u_wc = cq->queue;
 		uqueue = &u_wc->uqueue[0];
 		head = RDMA_READ_UAPI_ATOMIC(u_wc->head);
 		tail = RDMA_READ_UAPI_ATOMIC(u_wc->tail);
 	} else {
 		k_wc = cq->kqueue;
 		kqueue = &k_wc->kqueue[0];
 		head = k_wc->head;
 		tail = k_wc->tail;
 	}

 	/*
 	 * Note that the head pointer might be writable by
 	 * user processes.Take care to verify it is a sane value.
 	 */
 	if (head >= (unsigned)cq->ibcq.cqe) {
 		head = cq->ibcq.cqe;
 		next = 0;
 	} else {
 		next = head + 1;
 	}

 	if (unlikely(next == tail || cq->cq_full)) {
 		struct rvt_dev_info *rdi = cq->rdi;

 		if (!cq->cq_full)
 			rvt_pr_err_ratelimited(rdi, "CQ is full!\n");
 		cq->cq_full = true;
 		spin_unlock_irqrestore(&cq->lock, flags);
 		if (cq->ibcq.event_handler) {
 			struct ib_event ev;

 			ev.device = cq->ibcq.device;
 			ev.element.cq = &cq->ibcq;
 			ev.event = IB_EVENT_CQ_ERR;
 			cq->ibcq.event_handler(&ev, cq->ibcq.cq_context);
 		}
 		return false;
 	}
 	trace_rvt_cq_enter(cq, entry, head);
 	if (uqueue) {
 		uqueue[head].wr_id = entry->wr_id;
 		uqueue[head].status = entry->status;
 		uqueue[head].opcode = entry->opcode;
 		uqueue[head].vendor_err = entry->vendor_err;
 		uqueue[head].byte_len = entry->byte_len;
 		uqueue[head].ex.imm_data = entry->ex.imm_data;
 		uqueue[head].qp_num = entry->qp->qp_num;
 		uqueue[head].src_qp = entry->src_qp;
 		uqueue[head].wc_flags = entry->wc_flags;
 		uqueue[head].pkey_index = entry->pkey_index;
 		uqueue[head].slid = ib_lid_cpu16(entry->slid);
 		uqueue[head].sl = entry->sl;
 		uqueue[head].dlid_path_bits = entry->dlid_path_bits;
 		uqueue[head].port_num = entry->port_num;
 		/* Make sure entry is written before the head index. */
 		RDMA_WRITE_UAPI_ATOMIC(u_wc->head, next);
 	} else {
 		kqueue[head] = *entry;
 		k_wc->head = next;
 	}

 	if (cq->notify == IB_CQ_NEXT_COMP ||
 	    (cq->notify == IB_CQ_SOLICITED &&
 	     (solicited || entry->status != IB_WC_SUCCESS))) {
 		/*
 		 * This will cause send_complete() to be called in
 		 * another thread.
 		 */
 		cq->notify = RVT_CQ_NONE;
 		cq->triggered++;
 		queue_work_on(cq->comp_vector_cpu, comp_vector_wq,
 			      &cq->comptask);
 	}

 	spin_unlock_irqrestore(&cq->lock, flags);
 	return true;
 }
 EXPORT_SYMBOL(rvt_cq_enter);

 static void send_complete(struct work_struct *work)
 {
 	struct rvt_cq *cq = container_of(work, struct rvt_cq, comptask);

 	/*
 	 * The completion handler will most likely rearm the notification
 	 * and poll for all pending entries.  If a new completion entry
 	 * is added while we are in this routine, queue_work()
 	 * won't call us again until we return so we check triggered to
 	 * see if we need to call the handler again.
 	 */
 	for (;;) {
 		u8 triggered = cq->triggered;

 		/*
 		 * IPoIB connected mode assumes the callback is from a
 		 * soft IRQ. We simulate this by blocking "bottom halves".
 		 * See the implementation for ipoib_cm_handle_tx_wc(),
 		 * netif_tx_lock_bh() and netif_tx_lock().
 		 */
 		local_bh_disable();
 		cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);
 		local_bh_enable();

 		if (cq->triggered == triggered)
 			return;
 	}
 }

 /**
  * rvt_create_cq - create a completion queue
  * @ibcq: Allocated CQ
  * @attr: creation attributes
  * @udata: user data for libibverbs.so
  *
  * Called by ib_create_cq() in the generic verbs code.
  *
  * Return: 0 on success
  */
 int rvt_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
 		  struct ib_udata *udata)
 {
 	struct ib_device *ibdev = ibcq->device;
 	struct rvt_dev_info *rdi = ib_to_rvt(ibdev);
 	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
 	struct rvt_cq_wc *u_wc = NULL;
 	struct rvt_k_cq_wc *k_wc = NULL;
 	u32 sz;
 	unsigned int entries = attr->cqe;
 	int comp_vector = attr->comp_vector;
 	int err;

 	if (attr->flags)
 		return -EINVAL;

 	if (entries < 1 || entries > rdi->dparms.props.max_cqe)
 		return -EINVAL;

 	if (comp_vector < 0)
 		comp_vector = 0;

 	comp_vector = comp_vector % rdi->ibdev.num_comp_vectors;

 	/*
 	 * Allocate the completion queue entries and head/tail pointers.
 	 * This is allocated separately so that it can be resized and
 	 * also mapped into user space.
 	 * We need to use vmalloc() in order to support mmap and large
 	 * numbers of entries.
 	 */
 	if (udata && udata->outlen >= sizeof(__u64)) {
 		sz = sizeof(struct ib_uverbs_wc) * (entries + 1);
 		sz += sizeof(*u_wc);
 		u_wc = vmalloc_user(sz);
 		if (!u_wc)
 			return -ENOMEM;
 	} else {
 		sz = sizeof(struct ib_wc) * (entries + 1);
 		sz += sizeof(*k_wc);
 		k_wc = vzalloc_node(sz, rdi->dparms.node);
 		if (!k_wc)
 			return -ENOMEM;
 	}

 	/*
 	 * Return the address of the WC as the offset to mmap.
 	 * See rvt_mmap() for details.
 	 */
 	if (udata && udata->outlen >= sizeof(__u64)) {
 		cq->ip = rvt_create_mmap_info(rdi, sz, udata, u_wc);
 		if (IS_ERR(cq->ip)) {
 			err = PTR_ERR(cq->ip);
 			goto bail_wc;
 		}

 		err = ib_copy_to_udata(udata, &cq->ip->offset,
 				       sizeof(cq->ip->offset));
 		if (err)
 			goto bail_ip;
 	}

 	spin_lock_irq(&rdi->n_cqs_lock);
 	if (rdi->n_cqs_allocated == rdi->dparms.props.max_cq) {
 		spin_unlock_irq(&rdi->n_cqs_lock);
 		err = -ENOMEM;
 		goto bail_ip;
 	}

 	rdi->n_cqs_allocated++;
 	spin_unlock_irq(&rdi->n_cqs_lock);

 	if (cq->ip) {
 		spin_lock_irq(&rdi->pending_lock);
 		list_add(&cq->ip->pending_mmaps, &rdi->pending_mmaps);
 		spin_unlock_irq(&rdi->pending_lock);
 	}

 	/*
 	 * ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
 	 * The number of entries should be >= the number requested or return
 	 * an error.
 	 */
 	cq->rdi = rdi;
 	if (rdi->driver_f.comp_vect_cpu_lookup)
 		cq->comp_vector_cpu =
 			rdi->driver_f.comp_vect_cpu_lookup(rdi, comp_vector);
 	else
 		cq->comp_vector_cpu =
 			cpumask_first(cpumask_of_node(rdi->dparms.node));

 	cq->ibcq.cqe = entries;
 	cq->notify = RVT_CQ_NONE;
 	spin_lock_init(&cq->lock);
 	INIT_WORK(&cq->comptask, send_complete);
 	if (u_wc)
 		cq->queue = u_wc;
 	else
 		cq->kqueue = k_wc;

 	trace_rvt_create_cq(cq, attr);
 	return 0;

 bail_ip:
 	kfree(cq->ip);
 bail_wc:
 	vfree(u_wc);
 	vfree(k_wc);
 	return err;
 }

 /**
  * rvt_destroy_cq - destroy a completion queue
  * @ibcq: the completion queue to destroy.
  * @udata: user data or NULL for kernel object
  *
  * Called by ib_destroy_cq() in the generic verbs code.
  */
 void rvt_destroy_cq(struct ib_cq *ibcq, struct ib_udata *udata)
 {
 	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
 	struct rvt_dev_info *rdi = cq->rdi;

 	flush_work(&cq->comptask);
 	spin_lock_irq(&rdi->n_cqs_lock);
 	rdi->n_cqs_allocated--;
 	spin_unlock_irq(&rdi->n_cqs_lock);
 	if (cq->ip)
 		kref_put(&cq->ip->ref, rvt_release_mmap_info);
 	else
 		vfree(cq->kqueue);
 }

 /**
  * rvt_req_notify_cq - change the notification type for a completion queue
  * @ibcq: the completion queue
  * @notify_flags: the type of notification to request
  *
  * This may be called from interrupt context.  Also called by
  * ib_req_notify_cq() in the generic verbs code.
  *
  * Return: 0 for success.
  */
 int rvt_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags notify_flags)
 {
 	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
 	unsigned long flags;
 	int ret = 0;

 	spin_lock_irqsave(&cq->lock, flags);
 	/*
 	 * Don't change IB_CQ_NEXT_COMP to IB_CQ_SOLICITED but allow
 	 * any other transitions (see C11-31 and C11-32 in ch. 11.4.2.2).
 	 */
 	if (cq->notify != IB_CQ_NEXT_COMP)
 		cq->notify = notify_flags & IB_CQ_SOLICITED_MASK;

 	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
 		if (cq->queue) {
 			if (RDMA_READ_UAPI_ATOMIC(cq->queue->head) !=
 				RDMA_READ_UAPI_ATOMIC(cq->queue->tail))
 				ret = 1;
 		} else {
 			if (cq->kqueue->head != cq->kqueue->tail)
 				ret = 1;
 		}
 	}

 	spin_unlock_irqrestore(&cq->lock, flags);

 	return ret;
 }

 /**
  * rvt_resize_cq - change the size of the CQ
  * @ibcq: the completion queue
  *
  * Return: 0 for success.
  */
 int rvt_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
 {
 	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
 	u32 head, tail, n;
 	int ret;
 	u32 sz;
 	struct rvt_dev_info *rdi = cq->rdi;
 	struct rvt_cq_wc *u_wc = NULL;
 	struct rvt_cq_wc *old_u_wc = NULL;
 	struct rvt_k_cq_wc *k_wc = NULL;
 	struct rvt_k_cq_wc *old_k_wc = NULL;

 	if (cqe < 1 || cqe > rdi->dparms.props.max_cqe)
 		return -EINVAL;

 	/*
 	 * Need to use vmalloc() if we want to support large #s of entries.
 	 */
 	if (udata && udata->outlen >= sizeof(__u64)) {
 		sz = sizeof(struct ib_uverbs_wc) * (cqe + 1);
 		sz += sizeof(*u_wc);
 		u_wc = vmalloc_user(sz);
 		if (!u_wc)
 			return -ENOMEM;
 	} else {
 		sz = sizeof(struct ib_wc) * (cqe + 1);
 		sz += sizeof(*k_wc);
 		k_wc = vzalloc_node(sz, rdi->dparms.node);
 		if (!k_wc)
 			return -ENOMEM;
 	}
 	/* Check that we can write the offset to mmap. */
 	if (udata && udata->outlen >= sizeof(__u64)) {
 		__u64 offset = 0;

 		ret = ib_copy_to_udata(udata, &offset, sizeof(offset));
 		if (ret)
 			goto bail_free;
 	}

 	spin_lock_irq(&cq->lock);
 	/*
 	 * Make sure head and tail are sane since they
 	 * might be user writable.
 	 */
 	if (u_wc) {
 		old_u_wc = cq->queue;
 		head = RDMA_READ_UAPI_ATOMIC(old_u_wc->head);
 		tail = RDMA_READ_UAPI_ATOMIC(old_u_wc->tail);
 	} else {
 		old_k_wc = cq->kqueue;
 		head = old_k_wc->head;
 		tail = old_k_wc->tail;
 	}

 	if (head > (u32)cq->ibcq.cqe)
 		head = (u32)cq->ibcq.cqe;
 	if (tail > (u32)cq->ibcq.cqe)
 		tail = (u32)cq->ibcq.cqe;
 	if (head < tail)
 		n = cq->ibcq.cqe + 1 + head - tail;
 	else
 		n = head - tail;
 	if (unlikely((u32)cqe < n)) {
 		ret = -EINVAL;
 		goto bail_unlock;
 	}
 	for (n = 0; tail != head; n++) {
 		if (u_wc)
 			u_wc->uqueue[n] = old_u_wc->uqueue[tail];
 		else
 			k_wc->kqueue[n] = old_k_wc->kqueue[tail];
 		if (tail == (u32)cq->ibcq.cqe)
 			tail = 0;
 		else
 			tail++;
 	}
 	cq->ibcq.cqe = cqe;
 	if (u_wc) {
 		RDMA_WRITE_UAPI_ATOMIC(u_wc->head, n);
 		RDMA_WRITE_UAPI_ATOMIC(u_wc->tail, 0);
 		cq->queue = u_wc;
 	} else {
 		k_wc->head = n;
 		k_wc->tail = 0;
 		cq->kqueue = k_wc;
 	}
 	spin_unlock_irq(&cq->lock);

 	if (u_wc)
 		vfree(old_u_wc);
 	else
 		vfree(old_k_wc);

 	if (cq->ip) {
 		struct rvt_mmap_info *ip = cq->ip;

 		rvt_update_mmap_info(rdi, ip, sz, u_wc);

 		/*
 		 * Return the offset to mmap.
 		 * See rvt_mmap() for details.
 		 */
 		if (udata && udata->outlen >= sizeof(__u64)) {
 			ret = ib_copy_to_udata(udata, &ip->offset,
 					       sizeof(ip->offset));
 			if (ret)
 				return ret;
 		}

 		spin_lock_irq(&rdi->pending_lock);
 		if (list_empty(&ip->pending_mmaps))
 			list_add(&ip->pending_mmaps, &rdi->pending_mmaps);
 		spin_unlock_irq(&rdi->pending_lock);
 	}

 	return 0;

 bail_unlock:
 	spin_unlock_irq(&cq->lock);
 bail_free:
 	vfree(u_wc);
 	vfree(k_wc);

 	return ret;
 }

 /**
  * rvt_poll_cq - poll for work completion entries
  * @ibcq: the completion queue to poll
  * @num_entries: the maximum number of entries to return
  * @entry: pointer to array where work completions are placed
  *
  * This may be called from interrupt context.  Also called by ib_poll_cq()
  * in the generic verbs code.
  *
  * Return: the number of completion entries polled.
  */
 int rvt_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 {
 	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
 	struct rvt_k_cq_wc *wc;
 	unsigned long flags;
 	int npolled;
 	u32 tail;

 	/* The kernel can only poll a kernel completion queue */
 	if (cq->ip)
 		return -EINVAL;

 	spin_lock_irqsave(&cq->lock, flags);

 	wc = cq->kqueue;
 	tail = wc->tail;
 	if (tail > (u32)cq->ibcq.cqe)
 		tail = (u32)cq->ibcq.cqe;
 	for (npolled = 0; npolled < num_entries; ++npolled, ++entry) {
 		if (tail == wc->head)
 			break;
 		/* The kernel doesn't need a RMB since it has the lock. */
 		trace_rvt_cq_poll(cq, &wc->kqueue[tail], npolled);
 		*entry = wc->kqueue[tail];
 		if (tail >= cq->ibcq.cqe)
 			tail = 0;
 		else
 			tail++;
 	}
 	wc->tail = tail;

 	spin_unlock_irqrestore(&cq->lock, flags);

 	return npolled;
 }

 /**
  * rvt_driver_cq_init - Init cq resources on behalf of driver
  * @rdi: rvt dev structure
  *
  * Return: 0 on success
  */
 int rvt_driver_cq_init(void)
 {
 	comp_vector_wq = alloc_workqueue("%s", WQ_HIGHPRI | WQ_CPU_INTENSIVE,
 					 0, "rdmavt_cq");
 	if (!comp_vector_wq)
 		return -ENOMEM;

 	return 0;
 }

 /**
  * rvt_cq_exit - tear down cq reources
  * @rdi: rvt dev structure
  */
 void rvt_cq_exit(void)
 {
 	destroy_workqueue(comp_vector_wq);
 	comp_vector_wq = NULL;
 }
	/*
	* Copyright(c) 2016 - 2018 Intel Corporation.
	*
	* This file is provided under a dual BSD/GPLv2 license. When using or
	* redistributing this file, you may do so under either license.
	*
	* GPL LICENSE SUMMARY
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of version 2 of the GNU General Public License as
	* published by the Free Software Foundation.
	*
	* 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 for more details.
	*
	* BSD 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.
	* - Neither the name of Intel Corporation nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* 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
	* OWNER 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 <linux/slab.h>
	#include <linux/vmalloc.h>
	#include "cq.h"
	#include "vt.h"
	#include "trace.h"

	static struct workqueue_struct *comp_vector_wq;

	/**
	* rvt_cq_enter - add a new entry to the completion queue
	* @cq: completion queue
	* @entry: work completion entry to add
	* @solicited: true if @entry is solicited
	*
	* This may be called with qp->s_lock held.
	*
	* Return: return true on success, else return
	* false if cq is full.
	*/
	bool rvt_cq_enter(struct rvt_cq cq, struct ib_wc entry, bool solicited)
	{
	struct ib_uverbs_wc *uqueue = NULL;
	struct ib_wc *kqueue = NULL;
	struct rvt_cq_wc *u_wc = NULL;
	struct rvt_k_cq_wc *k_wc = NULL;
	unsigned long flags;
	u32 head;
	u32 next;
	u32 tail;

	spin_lock_irqsave(&cq->lock, flags);

	if (cq->ip) {
	u_wc = cq->queue;
	uqueue = &u_wc->uqueue[0];
	head = RDMA_READ_UAPI_ATOMIC(u_wc->head);
	tail = RDMA_READ_UAPI_ATOMIC(u_wc->tail);
	} else {
	k_wc = cq->kqueue;
	kqueue = &k_wc->kqueue[0];
	head = k_wc->head;
	tail = k_wc->tail;
	}

	/*
	* Note that the head pointer might be writable by
	* user processes.Take care to verify it is a sane value.
	*/
	if (head >= (unsigned)cq->ibcq.cqe) {
	head = cq->ibcq.cqe;
	next = 0;
	} else {
	next = head + 1;
	}

	if (unlikely(next == tail \|\| cq->cq_full)) {
	struct rvt_dev_info *rdi = cq->rdi;

	if (!cq->cq_full)
	rvt_pr_err_ratelimited(rdi, "CQ is full!\n");
	cq->cq_full = true;
	spin_unlock_irqrestore(&cq->lock, flags);
	if (cq->ibcq.event_handler) {
	struct ib_event ev;

	ev.device = cq->ibcq.device;
	ev.element.cq = &cq->ibcq;
	ev.event = IB_EVENT_CQ_ERR;
	cq->ibcq.event_handler(&ev, cq->ibcq.cq_context);
	}
	return false;
	}
	trace_rvt_cq_enter(cq, entry, head);
	if (uqueue) {
	uqueue[head].wr_id = entry->wr_id;
	uqueue[head].status = entry->status;
	uqueue[head].opcode = entry->opcode;
	uqueue[head].vendor_err = entry->vendor_err;
	uqueue[head].byte_len = entry->byte_len;
	uqueue[head].ex.imm_data = entry->ex.imm_data;
	uqueue[head].qp_num = entry->qp->qp_num;
	uqueue[head].src_qp = entry->src_qp;
	uqueue[head].wc_flags = entry->wc_flags;
	uqueue[head].pkey_index = entry->pkey_index;
	uqueue[head].slid = ib_lid_cpu16(entry->slid);
	uqueue[head].sl = entry->sl;
	uqueue[head].dlid_path_bits = entry->dlid_path_bits;
	uqueue[head].port_num = entry->port_num;
	/* Make sure entry is written before the head index. */
	RDMA_WRITE_UAPI_ATOMIC(u_wc->head, next);
	} else {
	kqueue[head] = *entry;
	k_wc->head = next;
	}

	if (cq->notify == IB_CQ_NEXT_COMP \|\|
	(cq->notify == IB_CQ_SOLICITED &&
	(solicited \|\| entry->status != IB_WC_SUCCESS))) {
	/*
	* This will cause send_complete() to be called in
	* another thread.
	*/
	cq->notify = RVT_CQ_NONE;
	cq->triggered++;
	queue_work_on(cq->comp_vector_cpu, comp_vector_wq,
	&cq->comptask);
	}

	spin_unlock_irqrestore(&cq->lock, flags);
	return true;
	}
	EXPORT_SYMBOL(rvt_cq_enter);

	static void send_complete(struct work_struct *work)
	{
	struct rvt_cq *cq = container_of(work, struct rvt_cq, comptask);

	/*
	* The completion handler will most likely rearm the notification
	* and poll for all pending entries. If a new completion entry
	* is added while we are in this routine, queue_work()
	* won't call us again until we return so we check triggered to
	* see if we need to call the handler again.
	*/
	for (;;) {
	u8 triggered = cq->triggered;

	/*
	* IPoIB connected mode assumes the callback is from a
	* soft IRQ. We simulate this by blocking "bottom halves".
	* See the implementation for ipoib_cm_handle_tx_wc(),
	* netif_tx_lock_bh() and netif_tx_lock().
	*/
	local_bh_disable();
	cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);
	local_bh_enable();

	if (cq->triggered == triggered)
	return;
	}
	}

	/**
	* rvt_create_cq - create a completion queue
	* @ibcq: Allocated CQ
	* @attr: creation attributes
	* @udata: user data for libibverbs.so
	*
	* Called by ib_create_cq() in the generic verbs code.
	*
	* Return: 0 on success
	*/
	int rvt_create_cq(struct ib_cq ibcq, const struct ib_cq_init_attr attr,
	struct ib_udata *udata)
	{
	struct ib_device *ibdev = ibcq->device;
	struct rvt_dev_info *rdi = ib_to_rvt(ibdev);
	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
	struct rvt_cq_wc *u_wc = NULL;
	struct rvt_k_cq_wc *k_wc = NULL;
	u32 sz;
	unsigned int entries = attr->cqe;
	int comp_vector = attr->comp_vector;
	int err;

	if (attr->flags)
	return -EINVAL;

	if (entries < 1 \|\| entries > rdi->dparms.props.max_cqe)
	return -EINVAL;

	if (comp_vector < 0)
	comp_vector = 0;

	comp_vector = comp_vector % rdi->ibdev.num_comp_vectors;

	/*
	* Allocate the completion queue entries and head/tail pointers.
	* This is allocated separately so that it can be resized and
	* also mapped into user space.
	* We need to use vmalloc() in order to support mmap and large
	* numbers of entries.
	*/
	if (udata && udata->outlen >= sizeof(__u64)) {
	sz = sizeof(struct ib_uverbs_wc) * (entries + 1);
	sz += sizeof(*u_wc);
	u_wc = vmalloc_user(sz);
	if (!u_wc)
	return -ENOMEM;
	} else {
	sz = sizeof(struct ib_wc) * (entries + 1);
	sz += sizeof(*k_wc);
	k_wc = vzalloc_node(sz, rdi->dparms.node);
	if (!k_wc)
	return -ENOMEM;
	}

	/*
	* Return the address of the WC as the offset to mmap.
	* See rvt_mmap() for details.
	*/
	if (udata && udata->outlen >= sizeof(__u64)) {
	cq->ip = rvt_create_mmap_info(rdi, sz, udata, u_wc);
	if (IS_ERR(cq->ip)) {
	err = PTR_ERR(cq->ip);
	goto bail_wc;
	}

	err = ib_copy_to_udata(udata, &cq->ip->offset,
	sizeof(cq->ip->offset));
	if (err)
	goto bail_ip;
	}

	spin_lock_irq(&rdi->n_cqs_lock);
	if (rdi->n_cqs_allocated == rdi->dparms.props.max_cq) {
	spin_unlock_irq(&rdi->n_cqs_lock);
	err = -ENOMEM;
	goto bail_ip;
	}

	rdi->n_cqs_allocated++;
	spin_unlock_irq(&rdi->n_cqs_lock);

	if (cq->ip) {
	spin_lock_irq(&rdi->pending_lock);
	list_add(&cq->ip->pending_mmaps, &rdi->pending_mmaps);
	spin_unlock_irq(&rdi->pending_lock);
	}

	/*
	* ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
	* The number of entries should be >= the number requested or return
	* an error.
	*/
	cq->rdi = rdi;
	if (rdi->driver_f.comp_vect_cpu_lookup)
	cq->comp_vector_cpu =
	rdi->driver_f.comp_vect_cpu_lookup(rdi, comp_vector);
	else
	cq->comp_vector_cpu =
	cpumask_first(cpumask_of_node(rdi->dparms.node));

	cq->ibcq.cqe = entries;
	cq->notify = RVT_CQ_NONE;
	spin_lock_init(&cq->lock);
	INIT_WORK(&cq->comptask, send_complete);
	if (u_wc)
	cq->queue = u_wc;
	else
	cq->kqueue = k_wc;

	trace_rvt_create_cq(cq, attr);
	return 0;

	bail_ip:
	kfree(cq->ip);
	bail_wc:
	vfree(u_wc);
	vfree(k_wc);
	return err;
	}

	/**
	* rvt_destroy_cq - destroy a completion queue
	* @ibcq: the completion queue to destroy.
	* @udata: user data or NULL for kernel object
	*
	* Called by ib_destroy_cq() in the generic verbs code.
	*/
	void rvt_destroy_cq(struct ib_cq ibcq, struct ib_udata udata)
	{
	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
	struct rvt_dev_info *rdi = cq->rdi;

	flush_work(&cq->comptask);
	spin_lock_irq(&rdi->n_cqs_lock);
	rdi->n_cqs_allocated--;
	spin_unlock_irq(&rdi->n_cqs_lock);
	if (cq->ip)
	kref_put(&cq->ip->ref, rvt_release_mmap_info);
	else
	vfree(cq->kqueue);
	}

	/**
	* rvt_req_notify_cq - change the notification type for a completion queue
	* @ibcq: the completion queue
	* @notify_flags: the type of notification to request
	*
	* This may be called from interrupt context. Also called by
	* ib_req_notify_cq() in the generic verbs code.
	*
	* Return: 0 for success.
	*/
	int rvt_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags notify_flags)
	{
	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&cq->lock, flags);
	/*
	* Don't change IB_CQ_NEXT_COMP to IB_CQ_SOLICITED but allow
	* any other transitions (see C11-31 and C11-32 in ch. 11.4.2.2).
	*/
	if (cq->notify != IB_CQ_NEXT_COMP)
	cq->notify = notify_flags & IB_CQ_SOLICITED_MASK;

	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
	if (cq->queue) {
	if (RDMA_READ_UAPI_ATOMIC(cq->queue->head) !=
	RDMA_READ_UAPI_ATOMIC(cq->queue->tail))
	ret = 1;
	} else {
	if (cq->kqueue->head != cq->kqueue->tail)
	ret = 1;
	}
	}

	spin_unlock_irqrestore(&cq->lock, flags);

	return ret;
	}

	/**
	* rvt_resize_cq - change the size of the CQ
	* @ibcq: the completion queue
	*
	* Return: 0 for success.
	*/
	int rvt_resize_cq(struct ib_cq ibcq, int cqe, struct ib_udata udata)
	{
	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
	u32 head, tail, n;
	int ret;
	u32 sz;
	struct rvt_dev_info *rdi = cq->rdi;
	struct rvt_cq_wc *u_wc = NULL;
	struct rvt_cq_wc *old_u_wc = NULL;
	struct rvt_k_cq_wc *k_wc = NULL;
	struct rvt_k_cq_wc *old_k_wc = NULL;

	if (cqe < 1 \|\| cqe > rdi->dparms.props.max_cqe)
	return -EINVAL;

	/*
	* Need to use vmalloc() if we want to support large #s of entries.
	*/
	if (udata && udata->outlen >= sizeof(__u64)) {
	sz = sizeof(struct ib_uverbs_wc) * (cqe + 1);
	sz += sizeof(*u_wc);
	u_wc = vmalloc_user(sz);
	if (!u_wc)
	return -ENOMEM;
	} else {
	sz = sizeof(struct ib_wc) * (cqe + 1);
	sz += sizeof(*k_wc);
	k_wc = vzalloc_node(sz, rdi->dparms.node);
	if (!k_wc)
	return -ENOMEM;
	}
	/* Check that we can write the offset to mmap. */
	if (udata && udata->outlen >= sizeof(__u64)) {
	__u64 offset = 0;

	ret = ib_copy_to_udata(udata, &offset, sizeof(offset));
	if (ret)
	goto bail_free;
	}

	spin_lock_irq(&cq->lock);
	/*
	* Make sure head and tail are sane since they
	* might be user writable.
	*/
	if (u_wc) {
	old_u_wc = cq->queue;
	head = RDMA_READ_UAPI_ATOMIC(old_u_wc->head);
	tail = RDMA_READ_UAPI_ATOMIC(old_u_wc->tail);
	} else {
	old_k_wc = cq->kqueue;
	head = old_k_wc->head;
	tail = old_k_wc->tail;
	}

	if (head > (u32)cq->ibcq.cqe)
	head = (u32)cq->ibcq.cqe;
	if (tail > (u32)cq->ibcq.cqe)
	tail = (u32)cq->ibcq.cqe;
	if (head < tail)
	n = cq->ibcq.cqe + 1 + head - tail;
	else
	n = head - tail;
	if (unlikely((u32)cqe < n)) {
	ret = -EINVAL;
	goto bail_unlock;
	}
	for (n = 0; tail != head; n++) {
	if (u_wc)
	u_wc->uqueue[n] = old_u_wc->uqueue[tail];
	else
	k_wc->kqueue[n] = old_k_wc->kqueue[tail];
	if (tail == (u32)cq->ibcq.cqe)
	tail = 0;
	else
	tail++;
	}
	cq->ibcq.cqe = cqe;
	if (u_wc) {
	RDMA_WRITE_UAPI_ATOMIC(u_wc->head, n);
	RDMA_WRITE_UAPI_ATOMIC(u_wc->tail, 0);
	cq->queue = u_wc;
	} else {
	k_wc->head = n;
	k_wc->tail = 0;
	cq->kqueue = k_wc;
	}
	spin_unlock_irq(&cq->lock);

	if (u_wc)
	vfree(old_u_wc);
	else
	vfree(old_k_wc);

	if (cq->ip) {
	struct rvt_mmap_info *ip = cq->ip;

	rvt_update_mmap_info(rdi, ip, sz, u_wc);

	/*
	* Return the offset to mmap.
	* See rvt_mmap() for details.
	*/
	if (udata && udata->outlen >= sizeof(__u64)) {
	ret = ib_copy_to_udata(udata, &ip->offset,
	sizeof(ip->offset));
	if (ret)
	return ret;
	}

	spin_lock_irq(&rdi->pending_lock);
	if (list_empty(&ip->pending_mmaps))
	list_add(&ip->pending_mmaps, &rdi->pending_mmaps);
	spin_unlock_irq(&rdi->pending_lock);
	}

	return 0;

	bail_unlock:
	spin_unlock_irq(&cq->lock);
	bail_free:
	vfree(u_wc);
	vfree(k_wc);

	return ret;
	}

	/**
	* rvt_poll_cq - poll for work completion entries
	* @ibcq: the completion queue to poll
	* @num_entries: the maximum number of entries to return
	* @entry: pointer to array where work completions are placed
	*
	* This may be called from interrupt context. Also called by ib_poll_cq()
	* in the generic verbs code.
	*
	* Return: the number of completion entries polled.
	*/
	int rvt_poll_cq(struct ib_cq ibcq, int num_entries, struct ib_wc entry)
	{
	struct rvt_cq *cq = ibcq_to_rvtcq(ibcq);
	struct rvt_k_cq_wc *wc;
	unsigned long flags;
	int npolled;
	u32 tail;

	/* The kernel can only poll a kernel completion queue */
	if (cq->ip)
	return -EINVAL;

	spin_lock_irqsave(&cq->lock, flags);

	wc = cq->kqueue;
	tail = wc->tail;
	if (tail > (u32)cq->ibcq.cqe)
	tail = (u32)cq->ibcq.cqe;
	for (npolled = 0; npolled < num_entries; ++npolled, ++entry) {
	if (tail == wc->head)
	break;
	/* The kernel doesn't need a RMB since it has the lock. */
	trace_rvt_cq_poll(cq, &wc->kqueue[tail], npolled);
	*entry = wc->kqueue[tail];
	if (tail >= cq->ibcq.cqe)
	tail = 0;
	else
	tail++;
	}
	wc->tail = tail;

	spin_unlock_irqrestore(&cq->lock, flags);

	return npolled;
	}

	/**
	* rvt_driver_cq_init - Init cq resources on behalf of driver
	* @rdi: rvt dev structure
	*
	* Return: 0 on success
	*/
	int rvt_driver_cq_init(void)
	{
	comp_vector_wq = alloc_workqueue("%s", WQ_HIGHPRI \| WQ_CPU_INTENSIVE,
	0, "rdmavt_cq");
	if (!comp_vector_wq)
	return -ENOMEM;

	return 0;
	}

	/**
	* rvt_cq_exit - tear down cq reources
	* @rdi: rvt dev structure
	*/
	void rvt_cq_exit(void)
	{
	destroy_workqueue(comp_vector_wq);
	comp_vector_wq = NULL;
	}