drivers/infiniband/hw/vmw_pvrdma/pvrdma_mr.c - arm/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 <linux/list.h>
 #include <linux/slab.h>

 #include "pvrdma.h"

 /**
  * pvrdma_get_dma_mr - get a DMA memory region
  * @pd: protection domain
  * @acc: access flags
  *
  * @return: ib_mr pointer on success, otherwise returns an errno.
  */
 struct ib_mr *pvrdma_get_dma_mr(struct ib_pd *pd, int acc)
 {
 	struct pvrdma_dev *dev = to_vdev(pd->device);
 	struct pvrdma_user_mr *mr;
 	union pvrdma_cmd_req req;
 	union pvrdma_cmd_resp rsp;
 	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
 	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
 	int ret;

 	/* Support only LOCAL_WRITE flag for DMA MRs */
 	if (acc & ~IB_ACCESS_LOCAL_WRITE) {
 		dev_warn(&dev->pdev->dev,
 			 "unsupported dma mr access flags %#x\n", acc);
 		return ERR_PTR(-EOPNOTSUPP);
 	}

 	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
 	if (!mr)
 		return ERR_PTR(-ENOMEM);

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
 	cmd->pd_handle = to_vpd(pd)->pd_handle;
 	cmd->access_flags = acc;
 	cmd->flags = PVRDMA_MR_FLAG_DMA;

 	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
 	if (ret < 0) {
 		dev_warn(&dev->pdev->dev,
 			 "could not get DMA mem region, error: %d\n", ret);
 		kfree(mr);
 		return ERR_PTR(ret);
 	}

 	mr->mmr.mr_handle = resp->mr_handle;
 	mr->ibmr.lkey = resp->lkey;
 	mr->ibmr.rkey = resp->rkey;

 	return &mr->ibmr;
 }

 /**
  * pvrdma_reg_user_mr - register a userspace memory region
  * @pd: protection domain
  * @start: starting address
  * @length: length of region
  * @virt_addr: I/O virtual address
  * @access_flags: access flags for memory region
  * @udata: user data
  *
  * @return: ib_mr pointer on success, otherwise returns an errno.
  */
 struct ib_mr *pvrdma_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				 u64 virt_addr, int access_flags,
 				 struct ib_udata *udata)
 {
 	struct pvrdma_dev *dev = to_vdev(pd->device);
 	struct pvrdma_user_mr *mr = NULL;
 	struct ib_umem *umem;
 	union pvrdma_cmd_req req;
 	union pvrdma_cmd_resp rsp;
 	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
 	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
 	int nchunks;
 	int ret;
 	int entry;
 	struct scatterlist *sg;

 	if (length == 0 || length > dev->dsr->caps.max_mr_size) {
 		dev_warn(&dev->pdev->dev, "invalid mem region length\n");
 		return ERR_PTR(-EINVAL);
 	}

 	umem = ib_umem_get(pd->uobject->context, start,
 			   length, access_flags, 0);
 	if (IS_ERR(umem)) {
 		dev_warn(&dev->pdev->dev,
 			 "could not get umem for mem region\n");
 		return ERR_CAST(umem);
 	}

 	nchunks = 0;
 	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry)
 		nchunks += sg_dma_len(sg) >> PAGE_SHIFT;

 	if (nchunks < 0 || nchunks > PVRDMA_PAGE_DIR_MAX_PAGES) {
 		dev_warn(&dev->pdev->dev, "overflow %d pages in mem region\n",
 			 nchunks);
 		ret = -EINVAL;
 		goto err_umem;
 	}

 	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
 	if (!mr) {
 		ret = -ENOMEM;
 		goto err_umem;
 	}

 	mr->mmr.iova = virt_addr;
 	mr->mmr.size = length;
 	mr->umem = umem;

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

 	ret = pvrdma_page_dir_insert_umem(&mr->pdir, mr->umem, 0);
 	if (ret)
 		goto err_pdir;

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
 	cmd->start = start;
 	cmd->length = length;
 	cmd->pd_handle = to_vpd(pd)->pd_handle;
 	cmd->access_flags = access_flags;
 	cmd->nchunks = nchunks;
 	cmd->pdir_dma = mr->pdir.dir_dma;

 	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
 	if (ret < 0) {
 		dev_warn(&dev->pdev->dev,
 			 "could not register mem region, error: %d\n", ret);
 		goto err_pdir;
 	}

 	mr->mmr.mr_handle = resp->mr_handle;
 	mr->ibmr.lkey = resp->lkey;
 	mr->ibmr.rkey = resp->rkey;

 	return &mr->ibmr;

 err_pdir:
 	pvrdma_page_dir_cleanup(dev, &mr->pdir);
 err_umem:
 	ib_umem_release(umem);
 	kfree(mr);

 	return ERR_PTR(ret);
 }

 /**
  * pvrdma_alloc_mr - allocate a memory region
  * @pd: protection domain
  * @mr_type: type of memory region
  * @max_num_sg: maximum number of pages
  *
  * @return: ib_mr pointer on success, otherwise returns an errno.
  */
 struct ib_mr *pvrdma_alloc_mr(struct ib_pd *pd, enum ib_mr_type mr_type,
 			      u32 max_num_sg)
 {
 	struct pvrdma_dev *dev = to_vdev(pd->device);
 	struct pvrdma_user_mr *mr;
 	union pvrdma_cmd_req req;
 	union pvrdma_cmd_resp rsp;
 	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
 	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
 	int size = max_num_sg * sizeof(u64);
 	int ret;

 	if (mr_type != IB_MR_TYPE_MEM_REG ||
 	    max_num_sg > PVRDMA_MAX_FAST_REG_PAGES)
 		return ERR_PTR(-EINVAL);

 	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
 	if (!mr)
 		return ERR_PTR(-ENOMEM);

 	mr->pages = kzalloc(size, GFP_KERNEL);
 	if (!mr->pages) {
 		ret = -ENOMEM;
 		goto freemr;
 	}

 	ret = pvrdma_page_dir_init(dev, &mr->pdir, max_num_sg, false);
 	if (ret) {
 		dev_warn(&dev->pdev->dev,
 			 "failed to allocate page dir for mr\n");
 		ret = -ENOMEM;
 		goto freepages;
 	}

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
 	cmd->pd_handle = to_vpd(pd)->pd_handle;
 	cmd->access_flags = 0;
 	cmd->flags = PVRDMA_MR_FLAG_FRMR;
 	cmd->nchunks = max_num_sg;

 	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
 	if (ret < 0) {
 		dev_warn(&dev->pdev->dev,
 			 "could not create FR mem region, error: %d\n", ret);
 		goto freepdir;
 	}

 	mr->max_pages = max_num_sg;
 	mr->mmr.mr_handle = resp->mr_handle;
 	mr->ibmr.lkey = resp->lkey;
 	mr->ibmr.rkey = resp->rkey;
 	mr->page_shift = PAGE_SHIFT;
 	mr->umem = NULL;

 	return &mr->ibmr;

 freepdir:
 	pvrdma_page_dir_cleanup(dev, &mr->pdir);
 freepages:
 	kfree(mr->pages);
 freemr:
 	kfree(mr);
 	return ERR_PTR(ret);
 }

 /**
  * pvrdma_dereg_mr - deregister a memory region
  * @ibmr: memory region
  *
  * @return: 0 on success.
  */
 int pvrdma_dereg_mr(struct ib_mr *ibmr)
 {
 	struct pvrdma_user_mr *mr = to_vmr(ibmr);
 	struct pvrdma_dev *dev = to_vdev(ibmr->device);
 	union pvrdma_cmd_req req;
 	struct pvrdma_cmd_destroy_mr *cmd = &req.destroy_mr;
 	int ret;

 	memset(cmd, 0, sizeof(*cmd));
 	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_MR;
 	cmd->mr_handle = mr->mmr.mr_handle;
 	ret = pvrdma_cmd_post(dev, &req, NULL, 0);
 	if (ret < 0)
 		dev_warn(&dev->pdev->dev,
 			 "could not deregister mem region, error: %d\n", ret);

 	pvrdma_page_dir_cleanup(dev, &mr->pdir);
 	if (mr->umem)
 		ib_umem_release(mr->umem);

 	kfree(mr->pages);
 	kfree(mr);

 	return 0;
 }

 static int pvrdma_set_page(struct ib_mr *ibmr, u64 addr)
 {
 	struct pvrdma_user_mr *mr = to_vmr(ibmr);

 	if (mr->npages == mr->max_pages)
 		return -ENOMEM;

 	mr->pages[mr->npages++] = addr;
 	return 0;
 }

 int pvrdma_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg, int sg_nents,
 		     unsigned int *sg_offset)
 {
 	struct pvrdma_user_mr *mr = to_vmr(ibmr);
 	struct pvrdma_dev *dev = to_vdev(ibmr->device);
 	int ret;

 	mr->npages = 0;

 	ret = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, pvrdma_set_page);
 	if (ret < 0)
 		dev_warn(&dev->pdev->dev, "could not map sg to pages\n");

 	return ret;
 }
	/*
	* 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 <linux/list.h>
	#include <linux/slab.h>

	#include "pvrdma.h"

	/**
	* pvrdma_get_dma_mr - get a DMA memory region
	* @pd: protection domain
	* @acc: access flags
	*
	* @return: ib_mr pointer on success, otherwise returns an errno.
	*/
	struct ib_mr pvrdma_get_dma_mr(struct ib_pd pd, int acc)
	{
	struct pvrdma_dev *dev = to_vdev(pd->device);
	struct pvrdma_user_mr *mr;
	union pvrdma_cmd_req req;
	union pvrdma_cmd_resp rsp;
	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
	int ret;

	/* Support only LOCAL_WRITE flag for DMA MRs */
	if (acc & ~IB_ACCESS_LOCAL_WRITE) {
	dev_warn(&dev->pdev->dev,
	"unsupported dma mr access flags %#x\n", acc);
	return ERR_PTR(-EOPNOTSUPP);
	}

	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
	if (!mr)
	return ERR_PTR(-ENOMEM);

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
	cmd->pd_handle = to_vpd(pd)->pd_handle;
	cmd->access_flags = acc;
	cmd->flags = PVRDMA_MR_FLAG_DMA;

	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
	if (ret < 0) {
	dev_warn(&dev->pdev->dev,
	"could not get DMA mem region, error: %d\n", ret);
	kfree(mr);
	return ERR_PTR(ret);
	}

	mr->mmr.mr_handle = resp->mr_handle;
	mr->ibmr.lkey = resp->lkey;
	mr->ibmr.rkey = resp->rkey;

	return &mr->ibmr;
	}

	/**
	* pvrdma_reg_user_mr - register a userspace memory region
	* @pd: protection domain
	* @start: starting address
	* @length: length of region
	* @virt_addr: I/O virtual address
	* @access_flags: access flags for memory region
	* @udata: user data
	*
	* @return: ib_mr pointer on success, otherwise returns an errno.
	*/
	struct ib_mr pvrdma_reg_user_mr(struct ib_pd pd, u64 start, u64 length,
	u64 virt_addr, int access_flags,
	struct ib_udata *udata)
	{
	struct pvrdma_dev *dev = to_vdev(pd->device);
	struct pvrdma_user_mr *mr = NULL;
	struct ib_umem *umem;
	union pvrdma_cmd_req req;
	union pvrdma_cmd_resp rsp;
	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
	int nchunks;
	int ret;
	int entry;
	struct scatterlist *sg;

	if (length == 0 \|\| length > dev->dsr->caps.max_mr_size) {
	dev_warn(&dev->pdev->dev, "invalid mem region length\n");
	return ERR_PTR(-EINVAL);
	}

	umem = ib_umem_get(pd->uobject->context, start,
	length, access_flags, 0);
	if (IS_ERR(umem)) {
	dev_warn(&dev->pdev->dev,
	"could not get umem for mem region\n");
	return ERR_CAST(umem);
	}

	nchunks = 0;
	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry)
	nchunks += sg_dma_len(sg) >> PAGE_SHIFT;

	if (nchunks < 0 \|\| nchunks > PVRDMA_PAGE_DIR_MAX_PAGES) {
	dev_warn(&dev->pdev->dev, "overflow %d pages in mem region\n",
	nchunks);
	ret = -EINVAL;
	goto err_umem;
	}

	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
	if (!mr) {
	ret = -ENOMEM;
	goto err_umem;
	}

	mr->mmr.iova = virt_addr;
	mr->mmr.size = length;
	mr->umem = umem;

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

	ret = pvrdma_page_dir_insert_umem(&mr->pdir, mr->umem, 0);
	if (ret)
	goto err_pdir;

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
	cmd->start = start;
	cmd->length = length;
	cmd->pd_handle = to_vpd(pd)->pd_handle;
	cmd->access_flags = access_flags;
	cmd->nchunks = nchunks;
	cmd->pdir_dma = mr->pdir.dir_dma;

	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
	if (ret < 0) {
	dev_warn(&dev->pdev->dev,
	"could not register mem region, error: %d\n", ret);
	goto err_pdir;
	}

	mr->mmr.mr_handle = resp->mr_handle;
	mr->ibmr.lkey = resp->lkey;
	mr->ibmr.rkey = resp->rkey;

	return &mr->ibmr;

	err_pdir:
	pvrdma_page_dir_cleanup(dev, &mr->pdir);
	err_umem:
	ib_umem_release(umem);
	kfree(mr);

	return ERR_PTR(ret);
	}

	/**
	* pvrdma_alloc_mr - allocate a memory region
	* @pd: protection domain
	* @mr_type: type of memory region
	* @max_num_sg: maximum number of pages
	*
	* @return: ib_mr pointer on success, otherwise returns an errno.
	*/
	struct ib_mr pvrdma_alloc_mr(struct ib_pd pd, enum ib_mr_type mr_type,
	u32 max_num_sg)
	{
	struct pvrdma_dev *dev = to_vdev(pd->device);
	struct pvrdma_user_mr *mr;
	union pvrdma_cmd_req req;
	union pvrdma_cmd_resp rsp;
	struct pvrdma_cmd_create_mr *cmd = &req.create_mr;
	struct pvrdma_cmd_create_mr_resp *resp = &rsp.create_mr_resp;
	int size = max_num_sg * sizeof(u64);
	int ret;

	if (mr_type != IB_MR_TYPE_MEM_REG \|\|
	max_num_sg > PVRDMA_MAX_FAST_REG_PAGES)
	return ERR_PTR(-EINVAL);

	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
	if (!mr)
	return ERR_PTR(-ENOMEM);

	mr->pages = kzalloc(size, GFP_KERNEL);
	if (!mr->pages) {
	ret = -ENOMEM;
	goto freemr;
	}

	ret = pvrdma_page_dir_init(dev, &mr->pdir, max_num_sg, false);
	if (ret) {
	dev_warn(&dev->pdev->dev,
	"failed to allocate page dir for mr\n");
	ret = -ENOMEM;
	goto freepages;
	}

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_CREATE_MR;
	cmd->pd_handle = to_vpd(pd)->pd_handle;
	cmd->access_flags = 0;
	cmd->flags = PVRDMA_MR_FLAG_FRMR;
	cmd->nchunks = max_num_sg;

	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_MR_RESP);
	if (ret < 0) {
	dev_warn(&dev->pdev->dev,
	"could not create FR mem region, error: %d\n", ret);
	goto freepdir;
	}

	mr->max_pages = max_num_sg;
	mr->mmr.mr_handle = resp->mr_handle;
	mr->ibmr.lkey = resp->lkey;
	mr->ibmr.rkey = resp->rkey;
	mr->page_shift = PAGE_SHIFT;
	mr->umem = NULL;

	return &mr->ibmr;

	freepdir:
	pvrdma_page_dir_cleanup(dev, &mr->pdir);
	freepages:
	kfree(mr->pages);
	freemr:
	kfree(mr);
	return ERR_PTR(ret);
	}

	/**
	* pvrdma_dereg_mr - deregister a memory region
	* @ibmr: memory region
	*
	* @return: 0 on success.
	*/
	int pvrdma_dereg_mr(struct ib_mr *ibmr)
	{
	struct pvrdma_user_mr *mr = to_vmr(ibmr);
	struct pvrdma_dev *dev = to_vdev(ibmr->device);
	union pvrdma_cmd_req req;
	struct pvrdma_cmd_destroy_mr *cmd = &req.destroy_mr;
	int ret;

	memset(cmd, 0, sizeof(*cmd));
	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_MR;
	cmd->mr_handle = mr->mmr.mr_handle;
	ret = pvrdma_cmd_post(dev, &req, NULL, 0);
	if (ret < 0)
	dev_warn(&dev->pdev->dev,
	"could not deregister mem region, error: %d\n", ret);

	pvrdma_page_dir_cleanup(dev, &mr->pdir);
	if (mr->umem)
	ib_umem_release(mr->umem);

	kfree(mr->pages);
	kfree(mr);

	return 0;
	}

	static int pvrdma_set_page(struct ib_mr *ibmr, u64 addr)
	{
	struct pvrdma_user_mr *mr = to_vmr(ibmr);

	if (mr->npages == mr->max_pages)
	return -ENOMEM;

	mr->pages[mr->npages++] = addr;
	return 0;
	}

	int pvrdma_map_mr_sg(struct ib_mr ibmr, struct scatterlist sg, int sg_nents,
	unsigned int *sg_offset)
	{
	struct pvrdma_user_mr *mr = to_vmr(ibmr);
	struct pvrdma_dev *dev = to_vdev(ibmr->device);
	int ret;

	mr->npages = 0;

	ret = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, pvrdma_set_page);
	if (ret < 0)
	dev_warn(&dev->pdev->dev, "could not map sg to pages\n");

	return ret;
	}