drivers/infiniband/hw/qib/qib_keys.c - kernel/bruno - Git at Google

 /*
  * Copyright (c) 2006, 2007, 2009 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 "qib.h"

 /**
  * qib_alloc_lkey - allocate an lkey
  * @mr: memory region that this lkey protects
  * @dma_region: 0->normal key, 1->restricted DMA key
  *
  * Returns 0 if successful, otherwise returns -errno.
  *
  * Increments mr reference count as required.
  *
  * Sets the lkey field mr for non-dma regions.
  *
  */

 int qib_alloc_lkey(struct qib_mregion *mr, int dma_region)
 {
 	unsigned long flags;
 	u32 r;
 	u32 n;
 	int ret = 0;
 	struct qib_ibdev *dev = to_idev(mr->pd->device);
 	struct qib_lkey_table *rkt = &dev->lk_table;

 	spin_lock_irqsave(&rkt->lock, flags);

 	/* special case for dma_mr lkey == 0 */
 	if (dma_region) {
 		struct qib_mregion *tmr;

 		tmr = rcu_access_pointer(dev->dma_mr);
 		if (!tmr) {
 			qib_get_mr(mr);
 			rcu_assign_pointer(dev->dma_mr, mr);
 			mr->lkey_published = 1;
 		}
 		goto success;
 	}

 	/* Find the next available LKEY */
 	r = rkt->next;
 	n = r;
 	for (;;) {
 		if (rkt->table[r] == NULL)
 			break;
 		r = (r + 1) & (rkt->max - 1);
 		if (r == n)
 			goto bail;
 	}
 	rkt->next = (r + 1) & (rkt->max - 1);
 	/*
 	 * Make sure lkey is never zero which is reserved to indicate an
 	 * unrestricted LKEY.
 	 */
 	rkt->gen++;
 	/*
 	 * bits are capped in qib_verbs.c to insure enough bits
 	 * for generation number
 	 */
 	mr->lkey = (r << (32 - ib_qib_lkey_table_size)) |
 		((((1 << (24 - ib_qib_lkey_table_size)) - 1) & rkt->gen)
 		 << 8);
 	if (mr->lkey == 0) {
 		mr->lkey |= 1 << 8;
 		rkt->gen++;
 	}
 	qib_get_mr(mr);
 	rcu_assign_pointer(rkt->table[r], mr);
 	mr->lkey_published = 1;
 success:
 	spin_unlock_irqrestore(&rkt->lock, flags);
 out:
 	return ret;
 bail:
 	spin_unlock_irqrestore(&rkt->lock, flags);
 	ret = -ENOMEM;
 	goto out;
 }

 /**
  * qib_free_lkey - free an lkey
  * @mr: mr to free from tables
  */
 void qib_free_lkey(struct qib_mregion *mr)
 {
 	unsigned long flags;
 	u32 lkey = mr->lkey;
 	u32 r;
 	struct qib_ibdev *dev = to_idev(mr->pd->device);
 	struct qib_lkey_table *rkt = &dev->lk_table;

 	spin_lock_irqsave(&rkt->lock, flags);
 	if (!mr->lkey_published)
 		goto out;
 	if (lkey == 0)
 		RCU_INIT_POINTER(dev->dma_mr, NULL);
 	else {
 		r = lkey >> (32 - ib_qib_lkey_table_size);
 		RCU_INIT_POINTER(rkt->table[r], NULL);
 	}
 	qib_put_mr(mr);
 	mr->lkey_published = 0;
 out:
 	spin_unlock_irqrestore(&rkt->lock, flags);
 }

 /**
  * qib_lkey_ok - check IB SGE for validity and initialize
  * @rkt: table containing lkey to check SGE against
  * @pd: protection domain
  * @isge: outgoing internal SGE
  * @sge: SGE to check
  * @acc: access flags
  *
  * Return 1 if valid and successful, otherwise returns 0.
  *
  * increments the reference count upon success
  *
  * Check the IB SGE for validity and initialize our internal version
  * of it.
  */
 int qib_lkey_ok(struct qib_lkey_table *rkt, struct qib_pd *pd,
 		struct qib_sge *isge, struct ib_sge *sge, int acc)
 {
 	struct qib_mregion *mr;
 	unsigned n, m;
 	size_t off;

 	/*
 	 * We use LKEY == zero for kernel virtual addresses
 	 * (see qib_get_dma_mr and qib_dma.c).
 	 */
 	rcu_read_lock();
 	if (sge->lkey == 0) {
 		struct qib_ibdev *dev = to_idev(pd->ibpd.device);

 		if (pd->user)
 			goto bail;
 		mr = rcu_dereference(dev->dma_mr);
 		if (!mr)
 			goto bail;
 		if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
 			goto bail;
 		rcu_read_unlock();

 		isge->mr = mr;
 		isge->vaddr = (void *) sge->addr;
 		isge->length = sge->length;
 		isge->sge_length = sge->length;
 		isge->m = 0;
 		isge->n = 0;
 		goto ok;
 	}
 	mr = rcu_dereference(
 		rkt->table[(sge->lkey >> (32 - ib_qib_lkey_table_size))]);
 	if (unlikely(!mr || mr->lkey != sge->lkey || mr->pd != &pd->ibpd))
 		goto bail;

 	off = sge->addr - mr->user_base;
 	if (unlikely(sge->addr < mr->user_base ||
 		     off + sge->length > mr->length ||
 		     (mr->access_flags & acc) != acc))
 		goto bail;
 	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
 		goto bail;
 	rcu_read_unlock();

 	off += mr->offset;
 	if (mr->page_shift) {
 		/*
 		page sizes are uniform power of 2 so no loop is necessary
 		entries_spanned_by_off is the number of times the loop below
 		would have executed.
 		*/
 		size_t entries_spanned_by_off;

 		entries_spanned_by_off = off >> mr->page_shift;
 		off -= (entries_spanned_by_off << mr->page_shift);
 		m = entries_spanned_by_off/QIB_SEGSZ;
 		n = entries_spanned_by_off%QIB_SEGSZ;
 	} else {
 		m = 0;
 		n = 0;
 		while (off >= mr->map[m]->segs[n].length) {
 			off -= mr->map[m]->segs[n].length;
 			n++;
 			if (n >= QIB_SEGSZ) {
 				m++;
 				n = 0;
 			}
 		}
 	}
 	isge->mr = mr;
 	isge->vaddr = mr->map[m]->segs[n].vaddr + off;
 	isge->length = mr->map[m]->segs[n].length - off;
 	isge->sge_length = sge->length;
 	isge->m = m;
 	isge->n = n;
 ok:
 	return 1;
 bail:
 	rcu_read_unlock();
 	return 0;
 }

 /**
  * qib_rkey_ok - check the IB virtual address, length, and RKEY
  * @qp: qp for validation
  * @sge: SGE state
  * @len: length of data
  * @vaddr: virtual address to place data
  * @rkey: rkey to check
  * @acc: access flags
  *
  * Return 1 if successful, otherwise 0.
  *
  * increments the reference count upon success
  */
 int qib_rkey_ok(struct qib_qp *qp, struct qib_sge *sge,
 		u32 len, u64 vaddr, u32 rkey, int acc)
 {
 	struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
 	struct qib_mregion *mr;
 	unsigned n, m;
 	size_t off;

 	/*
 	 * We use RKEY == zero for kernel virtual addresses
 	 * (see qib_get_dma_mr and qib_dma.c).
 	 */
 	rcu_read_lock();
 	if (rkey == 0) {
 		struct qib_pd *pd = to_ipd(qp->ibqp.pd);
 		struct qib_ibdev *dev = to_idev(pd->ibpd.device);

 		if (pd->user)
 			goto bail;
 		mr = rcu_dereference(dev->dma_mr);
 		if (!mr)
 			goto bail;
 		if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
 			goto bail;
 		rcu_read_unlock();

 		sge->mr = mr;
 		sge->vaddr = (void *) vaddr;
 		sge->length = len;
 		sge->sge_length = len;
 		sge->m = 0;
 		sge->n = 0;
 		goto ok;
 	}

 	mr = rcu_dereference(
 		rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))]);
 	if (unlikely(!mr || mr->lkey != rkey || qp->ibqp.pd != mr->pd))
 		goto bail;

 	off = vaddr - mr->iova;
 	if (unlikely(vaddr < mr->iova || off + len > mr->length ||
 		     (mr->access_flags & acc) == 0))
 		goto bail;
 	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
 		goto bail;
 	rcu_read_unlock();

 	off += mr->offset;
 	if (mr->page_shift) {
 		/*
 		page sizes are uniform power of 2 so no loop is necessary
 		entries_spanned_by_off is the number of times the loop below
 		would have executed.
 		*/
 		size_t entries_spanned_by_off;

 		entries_spanned_by_off = off >> mr->page_shift;
 		off -= (entries_spanned_by_off << mr->page_shift);
 		m = entries_spanned_by_off/QIB_SEGSZ;
 		n = entries_spanned_by_off%QIB_SEGSZ;
 	} else {
 		m = 0;
 		n = 0;
 		while (off >= mr->map[m]->segs[n].length) {
 			off -= mr->map[m]->segs[n].length;
 			n++;
 			if (n >= QIB_SEGSZ) {
 				m++;
 				n = 0;
 			}
 		}
 	}
 	sge->mr = mr;
 	sge->vaddr = mr->map[m]->segs[n].vaddr + off;
 	sge->length = mr->map[m]->segs[n].length - off;
 	sge->sge_length = len;
 	sge->m = m;
 	sge->n = n;
 ok:
 	return 1;
 bail:
 	rcu_read_unlock();
 	return 0;
 }

 /*
  * Initialize the memory region specified by the work request.
  */
 int qib_reg_mr(struct qib_qp *qp, struct ib_reg_wr *wr)
 {
 	struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
 	struct qib_pd *pd = to_ipd(qp->ibqp.pd);
 	struct qib_mr *mr = to_imr(wr->mr);
 	struct qib_mregion *mrg;
 	u32 key = wr->key;
 	unsigned i, n, m;
 	int ret = -EINVAL;
 	unsigned long flags;
 	u64 *page_list;
 	size_t ps;

 	spin_lock_irqsave(&rkt->lock, flags);
 	if (pd->user || key == 0)
 		goto bail;

 	mrg = rcu_dereference_protected(
 		rkt->table[(key >> (32 - ib_qib_lkey_table_size))],
 		lockdep_is_held(&rkt->lock));
 	if (unlikely(mrg == NULL || qp->ibqp.pd != mrg->pd))
 		goto bail;

 	if (mr->npages > mrg->max_segs)
 		goto bail;

 	ps = mr->ibmr.page_size;
 	if (mr->ibmr.length > ps * mr->npages)
 		goto bail;

 	mrg->user_base = mr->ibmr.iova;
 	mrg->iova = mr->ibmr.iova;
 	mrg->lkey = key;
 	mrg->length = mr->ibmr.length;
 	mrg->access_flags = wr->access;
 	page_list = mr->pages;
 	m = 0;
 	n = 0;
 	for (i = 0; i < mr->npages; i++) {
 		mrg->map[m]->segs[n].vaddr = (void *) page_list[i];
 		mrg->map[m]->segs[n].length = ps;
 		if (++n == QIB_SEGSZ) {
 			m++;
 			n = 0;
 		}
 	}

 	ret = 0;
 bail:
 	spin_unlock_irqrestore(&rkt->lock, flags);
 	return ret;
 }
	/*
	* Copyright (c) 2006, 2007, 2009 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 "qib.h"

	/**
	* qib_alloc_lkey - allocate an lkey
	* @mr: memory region that this lkey protects
	* @dma_region: 0->normal key, 1->restricted DMA key
	*
	* Returns 0 if successful, otherwise returns -errno.
	*
	* Increments mr reference count as required.
	*
	* Sets the lkey field mr for non-dma regions.
	*
	*/

	int qib_alloc_lkey(struct qib_mregion *mr, int dma_region)
	{
	unsigned long flags;
	u32 r;
	u32 n;
	int ret = 0;
	struct qib_ibdev *dev = to_idev(mr->pd->device);
	struct qib_lkey_table *rkt = &dev->lk_table;

	spin_lock_irqsave(&rkt->lock, flags);

	/* special case for dma_mr lkey == 0 */
	if (dma_region) {
	struct qib_mregion *tmr;

	tmr = rcu_access_pointer(dev->dma_mr);
	if (!tmr) {
	qib_get_mr(mr);
	rcu_assign_pointer(dev->dma_mr, mr);
	mr->lkey_published = 1;
	}
	goto success;
	}

	/* Find the next available LKEY */
	r = rkt->next;
	n = r;
	for (;;) {
	if (rkt->table[r] == NULL)
	break;
	r = (r + 1) & (rkt->max - 1);
	if (r == n)
	goto bail;
	}
	rkt->next = (r + 1) & (rkt->max - 1);
	/*
	* Make sure lkey is never zero which is reserved to indicate an
	* unrestricted LKEY.
	*/
	rkt->gen++;
	/*
	* bits are capped in qib_verbs.c to insure enough bits
	* for generation number
	*/
	mr->lkey = (r << (32 - ib_qib_lkey_table_size)) \|
	((((1 << (24 - ib_qib_lkey_table_size)) - 1) & rkt->gen)
	<< 8);
	if (mr->lkey == 0) {
	mr->lkey \|= 1 << 8;
	rkt->gen++;
	}
	qib_get_mr(mr);
	rcu_assign_pointer(rkt->table[r], mr);
	mr->lkey_published = 1;
	success:
	spin_unlock_irqrestore(&rkt->lock, flags);
	out:
	return ret;
	bail:
	spin_unlock_irqrestore(&rkt->lock, flags);
	ret = -ENOMEM;
	goto out;
	}

	/**
	* qib_free_lkey - free an lkey
	* @mr: mr to free from tables
	*/
	void qib_free_lkey(struct qib_mregion *mr)
	{
	unsigned long flags;
	u32 lkey = mr->lkey;
	u32 r;
	struct qib_ibdev *dev = to_idev(mr->pd->device);
	struct qib_lkey_table *rkt = &dev->lk_table;

	spin_lock_irqsave(&rkt->lock, flags);
	if (!mr->lkey_published)
	goto out;
	if (lkey == 0)
	RCU_INIT_POINTER(dev->dma_mr, NULL);
	else {
	r = lkey >> (32 - ib_qib_lkey_table_size);
	RCU_INIT_POINTER(rkt->table[r], NULL);
	}
	qib_put_mr(mr);
	mr->lkey_published = 0;
	out:
	spin_unlock_irqrestore(&rkt->lock, flags);
	}

	/**
	* qib_lkey_ok - check IB SGE for validity and initialize
	* @rkt: table containing lkey to check SGE against
	* @pd: protection domain
	* @isge: outgoing internal SGE
	* @sge: SGE to check
	* @acc: access flags
	*
	* Return 1 if valid and successful, otherwise returns 0.
	*
	* increments the reference count upon success
	*
	* Check the IB SGE for validity and initialize our internal version
	* of it.
	*/
	int qib_lkey_ok(struct qib_lkey_table rkt, struct qib_pd pd,
	struct qib_sge isge, struct ib_sge sge, int acc)
	{
	struct qib_mregion *mr;
	unsigned n, m;
	size_t off;

	/*
	* We use LKEY == zero for kernel virtual addresses
	* (see qib_get_dma_mr and qib_dma.c).
	*/
	rcu_read_lock();
	if (sge->lkey == 0) {
	struct qib_ibdev *dev = to_idev(pd->ibpd.device);

	if (pd->user)
	goto bail;
	mr = rcu_dereference(dev->dma_mr);
	if (!mr)
	goto bail;
	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
	goto bail;
	rcu_read_unlock();

	isge->mr = mr;
	isge->vaddr = (void *) sge->addr;
	isge->length = sge->length;
	isge->sge_length = sge->length;
	isge->m = 0;
	isge->n = 0;
	goto ok;
	}
	mr = rcu_dereference(
	rkt->table[(sge->lkey >> (32 - ib_qib_lkey_table_size))]);
	if (unlikely(!mr \|\| mr->lkey != sge->lkey \|\| mr->pd != &pd->ibpd))
	goto bail;

	off = sge->addr - mr->user_base;
	if (unlikely(sge->addr < mr->user_base \|\|
	off + sge->length > mr->length \|\|
	(mr->access_flags & acc) != acc))
	goto bail;
	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
	goto bail;
	rcu_read_unlock();

	off += mr->offset;
	if (mr->page_shift) {
	/*
	page sizes are uniform power of 2 so no loop is necessary
	entries_spanned_by_off is the number of times the loop below
	would have executed.
	*/
	size_t entries_spanned_by_off;

	entries_spanned_by_off = off >> mr->page_shift;
	off -= (entries_spanned_by_off << mr->page_shift);
	m = entries_spanned_by_off/QIB_SEGSZ;
	n = entries_spanned_by_off%QIB_SEGSZ;
	} else {
	m = 0;
	n = 0;
	while (off >= mr->map[m]->segs[n].length) {
	off -= mr->map[m]->segs[n].length;
	n++;
	if (n >= QIB_SEGSZ) {
	m++;
	n = 0;
	}
	}
	}
	isge->mr = mr;
	isge->vaddr = mr->map[m]->segs[n].vaddr + off;
	isge->length = mr->map[m]->segs[n].length - off;
	isge->sge_length = sge->length;
	isge->m = m;
	isge->n = n;
	ok:
	return 1;
	bail:
	rcu_read_unlock();
	return 0;
	}

	/**
	* qib_rkey_ok - check the IB virtual address, length, and RKEY
	* @qp: qp for validation
	* @sge: SGE state
	* @len: length of data
	* @vaddr: virtual address to place data
	* @rkey: rkey to check
	* @acc: access flags
	*
	* Return 1 if successful, otherwise 0.
	*
	* increments the reference count upon success
	*/
	int qib_rkey_ok(struct qib_qp qp, struct qib_sge sge,
	u32 len, u64 vaddr, u32 rkey, int acc)
	{
	struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
	struct qib_mregion *mr;
	unsigned n, m;
	size_t off;

	/*
	* We use RKEY == zero for kernel virtual addresses
	* (see qib_get_dma_mr and qib_dma.c).
	*/
	rcu_read_lock();
	if (rkey == 0) {
	struct qib_pd *pd = to_ipd(qp->ibqp.pd);
	struct qib_ibdev *dev = to_idev(pd->ibpd.device);

	if (pd->user)
	goto bail;
	mr = rcu_dereference(dev->dma_mr);
	if (!mr)
	goto bail;
	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
	goto bail;
	rcu_read_unlock();

	sge->mr = mr;
	sge->vaddr = (void *) vaddr;
	sge->length = len;
	sge->sge_length = len;
	sge->m = 0;
	sge->n = 0;
	goto ok;
	}

	mr = rcu_dereference(
	rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))]);
	if (unlikely(!mr \|\| mr->lkey != rkey \|\| qp->ibqp.pd != mr->pd))
	goto bail;

	off = vaddr - mr->iova;
	if (unlikely(vaddr < mr->iova \|\| off + len > mr->length \|\|
	(mr->access_flags & acc) == 0))
	goto bail;
	if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
	goto bail;
	rcu_read_unlock();

	off += mr->offset;
	if (mr->page_shift) {
	/*
	page sizes are uniform power of 2 so no loop is necessary
	entries_spanned_by_off is the number of times the loop below
	would have executed.
	*/
	size_t entries_spanned_by_off;

	entries_spanned_by_off = off >> mr->page_shift;
	off -= (entries_spanned_by_off << mr->page_shift);
	m = entries_spanned_by_off/QIB_SEGSZ;
	n = entries_spanned_by_off%QIB_SEGSZ;
	} else {
	m = 0;
	n = 0;
	while (off >= mr->map[m]->segs[n].length) {
	off -= mr->map[m]->segs[n].length;
	n++;
	if (n >= QIB_SEGSZ) {
	m++;
	n = 0;
	}
	}
	}
	sge->mr = mr;
	sge->vaddr = mr->map[m]->segs[n].vaddr + off;
	sge->length = mr->map[m]->segs[n].length - off;
	sge->sge_length = len;
	sge->m = m;
	sge->n = n;
	ok:
	return 1;
	bail:
	rcu_read_unlock();
	return 0;
	}

	/*
	* Initialize the memory region specified by the work request.
	*/
	int qib_reg_mr(struct qib_qp qp, struct ib_reg_wr wr)
	{
	struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
	struct qib_pd *pd = to_ipd(qp->ibqp.pd);
	struct qib_mr *mr = to_imr(wr->mr);
	struct qib_mregion *mrg;
	u32 key = wr->key;
	unsigned i, n, m;
	int ret = -EINVAL;
	unsigned long flags;
	u64 *page_list;
	size_t ps;

	spin_lock_irqsave(&rkt->lock, flags);
	if (pd->user \|\| key == 0)
	goto bail;

	mrg = rcu_dereference_protected(
	rkt->table[(key >> (32 - ib_qib_lkey_table_size))],
	lockdep_is_held(&rkt->lock));
	if (unlikely(mrg == NULL \|\| qp->ibqp.pd != mrg->pd))
	goto bail;

	if (mr->npages > mrg->max_segs)
	goto bail;

	ps = mr->ibmr.page_size;
	if (mr->ibmr.length > ps * mr->npages)
	goto bail;

	mrg->user_base = mr->ibmr.iova;
	mrg->iova = mr->ibmr.iova;
	mrg->lkey = key;
	mrg->length = mr->ibmr.length;
	mrg->access_flags = wr->access;
	page_list = mr->pages;
	m = 0;
	n = 0;
	for (i = 0; i < mr->npages; i++) {
	mrg->map[m]->segs[n].vaddr = (void *) page_list[i];
	mrg->map[m]->segs[n].length = ps;
	if (++n == QIB_SEGSZ) {
	m++;
	n = 0;
	}
	}

	ret = 0;
	bail:
	spin_unlock_irqrestore(&rkt->lock, flags);
	return ret;
	}