ipath_srq.c

/*
 * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/err.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "ipath_verbs.h"

/**
 * ipath_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: the first WR to cause a problem is put here
 *
 * This may be called from interrupt context.
 */
int ipath_post_srq_receive(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
			   struct ib_recv_wr **bad_wr)
{
	struct ipath_srq *srq = to_isrq(ibsrq);
	struct ipath_rwq *wq;
	unsigned long flags;
	int ret;

	for (; wr; wr = wr->next) {
		struct ipath_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;
}

/**
 * ipath_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 libipathverbs when creating a user SRQ
 */
struct ib_srq *ipath_create_srq(struct ib_pd *ibpd,
				struct ib_srq_init_attr *srq_init_attr,
				struct ib_udata *udata)
{
	struct ipath_ibdev *dev = to_idev(ibpd->device);
	struct ipath_srq *srq;
	u32 sz;
	struct ib_srq *ret;

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

	if ((srq_init_attr->attr.max_sge > ib_ipath_max_srq_sges) ||
	    (srq_init_attr->attr.max_wr > ib_ipath_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 ipath_rwqe);
	srq->rq.wq = vmalloc_user(sizeof(struct ipath_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 ipath_mmap() for details.
	 */
	if (udata && udata->outlen >= sizeof(__u64)) {
		int err;
		u32 s = sizeof(struct ipath_rwq) + srq->rq.size * sz;

		srq->ip =
		    ipath_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 == ib_ipath_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;
}

/**
 * ipath_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 ipathverbs.so
 */
int ipath_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
		     enum ib_srq_attr_mask attr_mask,
		     struct ib_udata *udata)
{
	struct ipath_srq *srq = to_isrq(ibsrq);
	struct ipath_rwq *wq;
	int ret = 0;

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

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

		sz = sizeof(struct ipath_rwqe) +
			srq->rq.max_sge * sizeof(struct ib_sge);
		size = attr->max_wr + 1;
		wq = vmalloc_user(sizeof(struct ipath_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 pointer value and compute
		 * the number of remaining WQEs.
		 */
		owq = srq->rq.wq;
		head = owq->head;
		if (head >= srq->rq.size)
			head = 0;
		tail = owq->tail;
		if (tail >= srq->rq.size)
			tail = 0;
		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 ipath_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 ipath_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 ipath_mmap_info *ip = srq->ip;
			struct ipath_ibdev *dev = to_idev(srq->ibsrq.device);
			u32 s = sizeof(struct ipath_rwq) + size * sz;

			ipath_update_mmap_info(dev, ip, s, wq);

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

			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 ipath_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr)
{
	struct ipath_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;
}

/**
 * ipath_destroy_srq - destroy a shared receive queue
 * @ibsrq: the SRQ to destroy
 */
int ipath_destroy_srq(struct ib_srq *ibsrq)
{
	struct ipath_srq *srq = to_isrq(ibsrq);
	struct ipath_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, ipath_release_mmap_info);
	else
		vfree(srq->rq.wq);
	kfree(srq);

	return 0;
}