drivers/infiniband/hw/ipath/ipath_srq.c - kernel/skids - Git at Google

 /*
  * 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;
 }
	/*
	* 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;
	}