/*
 *
 * 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
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * 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
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * 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/err.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "verbs.h"

/**
 * hfi1_post_srq_receive - post a receive on a shared receive queue
 * @ibsrq: the SRQ to post the receive on
 * @wr: the list of work requests to post
 * @bad_wr: A pointer to the first WR to cause a problem is put here
 *
 * This may be called from interrupt context.
 */
int hfi1_post_srq_receive(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
			  struct ib_recv_wr **bad_wr)
{
	struct hfi1_srq *srq = to_isrq(ibsrq);
	struct hfi1_rwq *wq;
	unsigned long flags;
	int ret;

	for (; wr; wr = wr->next) {
		struct hfi1_rwqe *wqe;
		u32 next;
		int i;

		if ((unsigned) wr->num_sge > srq->rq.max_sge) {
			*bad_wr = wr;
			ret = -EINVAL;
			goto bail;
		}

		spin_lock_irqsave(&srq->rq.lock, flags);
		wq = srq->rq.wq;
		next = wq->head + 1;
		if (next >= srq->rq.size)
			next = 0;
		if (next == wq->tail) {
			spin_unlock_irqrestore(&srq->rq.lock, flags);
			*bad_wr = wr;
			ret = -ENOMEM;
			goto bail;
		}

		wqe = get_rwqe_ptr(&srq->rq, wq->head);
		wqe->wr_id = wr->wr_id;
		wqe->num_sge = wr->num_sge;
		for (i = 0; i < wr->num_sge; i++)
			wqe->sg_list[i] = wr->sg_list[i];
		/* Make sure queue entry is written before the head index. */
		smp_wmb();
		wq->head = next;
		spin_unlock_irqrestore(&srq->rq.lock, flags);
	}
	ret = 0;

bail:
	return ret;
}

/**
 * hfi1_create_srq - create a shared receive queue
 * @ibpd: the protection domain of the SRQ to create
 * @srq_init_attr: the attributes of the SRQ
 * @udata: data from libibverbs when creating a user SRQ
 */
struct ib_srq *hfi1_create_srq(struct ib_pd *ibpd,
			       struct ib_srq_init_attr *srq_init_attr,
			       struct ib_udata *udata)
{
	struct hfi1_ibdev *dev = to_idev(ibpd->device);
	struct hfi1_srq *srq;
	u32 sz;
	struct ib_srq *ret;

	if (srq_init_attr->srq_type != IB_SRQT_BASIC) {
		ret = ERR_PTR(-ENOSYS);
		goto done;
	}

	if (srq_init_attr->attr.max_sge == 0 ||
	    srq_init_attr->attr.max_sge > hfi1_max_srq_sges ||
	    srq_init_attr->attr.max_wr == 0 ||
	    srq_init_attr->attr.max_wr > hfi1_max_srq_wrs) {
		ret = ERR_PTR(-EINVAL);
		goto done;
	}

	srq = kmalloc(sizeof(*srq), GFP_KERNEL);
	if (!srq) {
		ret = ERR_PTR(-ENOMEM);
		goto done;
	}

	/*
	 * Need to use vmalloc() if we want to support large #s of entries.
	 */
	srq->rq.size = srq_init_attr->attr.max_wr + 1;
	srq->rq.max_sge = srq_init_attr->attr.max_sge;
	sz = sizeof(struct ib_sge) * srq->rq.max_sge +
		sizeof(struct hfi1_rwqe);
	srq->rq.wq = vmalloc_user(sizeof(struct hfi1_rwq) + srq->rq.size * sz);
	if (!srq->rq.wq) {
		ret = ERR_PTR(-ENOMEM);
		goto bail_srq;
	}

	/*
	 * Return the address of the RWQ as the offset to mmap.
	 * See hfi1_mmap() for details.
	 */
	if (udata && udata->outlen >= sizeof(__u64)) {
		int err;
		u32 s = sizeof(struct hfi1_rwq) + srq->rq.size * sz;

		srq->ip =
		    hfi1_create_mmap_info(dev, s, ibpd->uobject->context,
					  srq->rq.wq);
		if (!srq->ip) {
			ret = ERR_PTR(-ENOMEM);
			goto bail_wq;
		}

		err = ib_copy_to_udata(udata, &srq->ip->offset,
				       sizeof(srq->ip->offset));
		if (err) {
			ret = ERR_PTR(err);
			goto bail_ip;
		}
	} else
		srq->ip = NULL;

	/*
	 * ib_create_srq() will initialize srq->ibsrq.
	 */
	spin_lock_init(&srq->rq.lock);
	srq->rq.wq->head = 0;
	srq->rq.wq->tail = 0;
	srq->limit = srq_init_attr->attr.srq_limit;

	spin_lock(&dev->n_srqs_lock);
	if (dev->n_srqs_allocated == hfi1_max_srqs) {
		spin_unlock(&dev->n_srqs_lock);
		ret = ERR_PTR(-ENOMEM);
		goto bail_ip;
	}

	dev->n_srqs_allocated++;
	spin_unlock(&dev->n_srqs_lock);

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

	ret = &srq->ibsrq;
	goto done;

bail_ip:
	kfree(srq->ip);
bail_wq:
	vfree(srq->rq.wq);
bail_srq:
	kfree(srq);
done:
	return ret;
}

/**
 * hfi1_modify_srq - modify a shared receive queue
 * @ibsrq: the SRQ to modify
 * @attr: the new attributes of the SRQ
 * @attr_mask: indicates which attributes to modify
 * @udata: user data for libibverbs.so
 */
int hfi1_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
		    enum ib_srq_attr_mask attr_mask,
		    struct ib_udata *udata)
{
	struct hfi1_srq *srq = to_isrq(ibsrq);
	struct hfi1_rwq *wq;
	int ret = 0;

	if (attr_mask & IB_SRQ_MAX_WR) {
		struct hfi1_rwq *owq;
		struct hfi1_rwqe *p;
		u32 sz, size, n, head, tail;

		/* Check that the requested sizes are below the limits. */
		if ((attr->max_wr > hfi1_max_srq_wrs) ||
		    ((attr_mask & IB_SRQ_LIMIT) ?
		     attr->srq_limit : srq->limit) > attr->max_wr) {
			ret = -EINVAL;
			goto bail;
		}

		sz = sizeof(struct hfi1_rwqe) +
			srq->rq.max_sge * sizeof(struct ib_sge);
		size = attr->max_wr + 1;
		wq = vmalloc_user(sizeof(struct hfi1_rwq) + size * sz);
		if (!wq) {
			ret = -ENOMEM;
			goto bail;
		}

		/* Check that we can write the offset to mmap. */
		if (udata && udata->inlen >= sizeof(__u64)) {
			__u64 offset_addr;
			__u64 offset = 0;

			ret = ib_copy_from_udata(&offset_addr, udata,
						 sizeof(offset_addr));
			if (ret)
				goto bail_free;
			udata->outbuf =
				(void __user *) (unsigned long) offset_addr;
			ret = ib_copy_to_udata(udata, &offset,
					       sizeof(offset));
			if (ret)
				goto bail_free;
		}

		spin_lock_irq(&srq->rq.lock);
		/*
		 * validate head and tail pointer values and compute
		 * the number of remaining WQEs.
		 */
		owq = srq->rq.wq;
		head = owq->head;
		tail = owq->tail;
		if (head >= srq->rq.size || tail >= srq->rq.size) {
			ret = -EINVAL;
			goto bail_unlock;
		}
		n = head;
		if (n < tail)
			n += srq->rq.size - tail;
		else
			n -= tail;
		if (size <= n) {
			ret = -EINVAL;
			goto bail_unlock;
		}
		n = 0;
		p = wq->wq;
		while (tail != head) {
			struct hfi1_rwqe *wqe;
			int i;

			wqe = get_rwqe_ptr(&srq->rq, tail);
			p->wr_id = wqe->wr_id;
			p->num_sge = wqe->num_sge;
			for (i = 0; i < wqe->num_sge; i++)
				p->sg_list[i] = wqe->sg_list[i];
			n++;
			p = (struct hfi1_rwqe *)((char *)p + sz);
			if (++tail >= srq->rq.size)
				tail = 0;
		}
		srq->rq.wq = wq;
		srq->rq.size = size;
		wq->head = n;
		wq->tail = 0;
		if (attr_mask & IB_SRQ_LIMIT)
			srq->limit = attr->srq_limit;
		spin_unlock_irq(&srq->rq.lock);

		vfree(owq);

		if (srq->ip) {
			struct hfi1_mmap_info *ip = srq->ip;
			struct hfi1_ibdev *dev = to_idev(srq->ibsrq.device);
			u32 s = sizeof(struct hfi1_rwq) + size * sz;

			hfi1_update_mmap_info(dev, ip, s, wq);

			/*
			 * Return the offset to mmap.
			 * See hfi1_mmap() for details.
			 */
			if (udata && udata->inlen >= sizeof(__u64)) {
				ret = ib_copy_to_udata(udata, &ip->offset,
						       sizeof(ip->offset));
				if (ret)
					goto bail;
			}

			/*
			 * Put user mapping info onto the pending list
			 * unless it already is on the list.
			 */
			spin_lock_irq(&dev->pending_lock);
			if (list_empty(&ip->pending_mmaps))
				list_add(&ip->pending_mmaps,
					 &dev->pending_mmaps);
			spin_unlock_irq(&dev->pending_lock);
		}
	} else if (attr_mask & IB_SRQ_LIMIT) {
		spin_lock_irq(&srq->rq.lock);
		if (attr->srq_limit >= srq->rq.size)
			ret = -EINVAL;
		else
			srq->limit = attr->srq_limit;
		spin_unlock_irq(&srq->rq.lock);
	}
	goto bail;

bail_unlock:
	spin_unlock_irq(&srq->rq.lock);
bail_free:
	vfree(wq);
bail:
	return ret;
}

int hfi1_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr)
{
	struct hfi1_srq *srq = to_isrq(ibsrq);

	attr->max_wr = srq->rq.size - 1;
	attr->max_sge = srq->rq.max_sge;
	attr->srq_limit = srq->limit;
	return 0;
}

/**
 * hfi1_destroy_srq - destroy a shared receive queue
 * @ibsrq: the SRQ to destroy
 */
int hfi1_destroy_srq(struct ib_srq *ibsrq)
{
	struct hfi1_srq *srq = to_isrq(ibsrq);
	struct hfi1_ibdev *dev = to_idev(ibsrq->device);

	spin_lock(&dev->n_srqs_lock);
	dev->n_srqs_allocated--;
	spin_unlock(&dev->n_srqs_lock);
	if (srq->ip)
		kref_put(&srq->ip->ref, hfi1_release_mmap_info);
	else
		vfree(srq->rq.wq);
	kfree(srq);

	return 0;
}