[deliverable/linux.git] / drivers / infiniband / hw / mlx4 / srq.c

/*
 * Copyright (c) 2007 Cisco Systems, 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/mlx4/qp.h>
#include <linux/mlx4/srq.h>

#include "mlx4_ib.h"
#include "user.h"

static void *get_wqe(struct mlx4_ib_srq *srq, int n)
{
	return mlx4_buf_offset(&srq->buf, n << srq->msrq.wqe_shift);
}

static void mlx4_ib_srq_event(struct mlx4_srq *srq, enum mlx4_event type)
{
	struct ib_event event;
	struct ib_srq *ibsrq = &to_mibsrq(srq)->ibsrq;

	if (ibsrq->event_handler) {
		event.device      = ibsrq->device;
		event.element.srq = ibsrq;
		switch (type) {
		case MLX4_EVENT_TYPE_SRQ_LIMIT:
			event.event = IB_EVENT_SRQ_LIMIT_REACHED;
			break;
		case MLX4_EVENT_TYPE_SRQ_CATAS_ERROR:
			event.event = IB_EVENT_SRQ_ERR;
			break;
		default:
			printk(KERN_WARNING "mlx4_ib: Unexpected event type %d "
			       "on SRQ %06x\n", type, srq->srqn);
			return;
		}

		ibsrq->event_handler(&event, ibsrq->srq_context);
	}
}

struct ib_srq *mlx4_ib_create_srq(struct ib_pd *pd,
				  struct ib_srq_init_attr *init_attr,
				  struct ib_udata *udata)
{
	struct mlx4_ib_dev *dev = to_mdev(pd->device);
	struct mlx4_ib_srq *srq;
	struct mlx4_wqe_srq_next_seg *next;
	int desc_size;
	int buf_size;
	int err;
	int i;

	/* Sanity check SRQ size before proceeding */
	if (init_attr->attr.max_wr  >= dev->dev->caps.max_srq_wqes ||
	    init_attr->attr.max_sge >  dev->dev->caps.max_srq_sge)
		return ERR_PTR(-EINVAL);

	srq = kmalloc(sizeof *srq, GFP_KERNEL);
	if (!srq)
		return ERR_PTR(-ENOMEM);

	mutex_init(&srq->mutex);
	spin_lock_init(&srq->lock);
	srq->msrq.max    = roundup_pow_of_two(init_attr->attr.max_wr + 1);
	srq->msrq.max_gs = init_attr->attr.max_sge;

	desc_size = max(32UL,
			roundup_pow_of_two(sizeof (struct mlx4_wqe_srq_next_seg) +
					   srq->msrq.max_gs *
					   sizeof (struct mlx4_wqe_data_seg)));
	srq->msrq.wqe_shift = ilog2(desc_size);

	buf_size = srq->msrq.max * desc_size;

	if (pd->uobject) {
		struct mlx4_ib_create_srq ucmd;

		if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) {
			err = -EFAULT;
			goto err_srq;
		}

		srq->umem = ib_umem_get(pd->uobject->context, ucmd.buf_addr,
					buf_size, 0);
		if (IS_ERR(srq->umem)) {
			err = PTR_ERR(srq->umem);
			goto err_srq;
		}

		err = mlx4_mtt_init(dev->dev, ib_umem_page_count(srq->umem),
				    ilog2(srq->umem->page_size), &srq->mtt);
		if (err)
			goto err_buf;

		err = mlx4_ib_umem_write_mtt(dev, &srq->mtt, srq->umem);
		if (err)
			goto err_mtt;

		err = mlx4_ib_db_map_user(to_mucontext(pd->uobject->context),
					  ucmd.db_addr, &srq->db);
		if (err)
			goto err_mtt;
	} else {
		err = mlx4_ib_db_alloc(dev, &srq->db, 0);
		if (err)
			goto err_srq;

		*srq->db.db = 0;

		if (mlx4_buf_alloc(dev->dev, buf_size, PAGE_SIZE * 2, &srq->buf)) {
			err = -ENOMEM;
			goto err_db;
		}

		srq->head    = 0;
		srq->tail    = srq->msrq.max - 1;
		srq->wqe_ctr = 0;

		for (i = 0; i < srq->msrq.max; ++i) {
			next = get_wqe(srq, i);
			next->next_wqe_index =
				cpu_to_be16((i + 1) & (srq->msrq.max - 1));
		}

		err = mlx4_mtt_init(dev->dev, srq->buf.npages, srq->buf.page_shift,
				    &srq->mtt);
		if (err)
			goto err_buf;

		err = mlx4_buf_write_mtt(dev->dev, &srq->mtt, &srq->buf);
		if (err)
			goto err_mtt;

		srq->wrid = kmalloc(srq->msrq.max * sizeof (u64), GFP_KERNEL);
		if (!srq->wrid) {
			err = -ENOMEM;
			goto err_mtt;
		}
	}

	err = mlx4_srq_alloc(dev->dev, to_mpd(pd)->pdn, &srq->mtt,
			     srq->db.dma, &srq->msrq);
	if (err)
		goto err_wrid;

	srq->msrq.event = mlx4_ib_srq_event;

	if (pd->uobject)
		if (ib_copy_to_udata(udata, &srq->msrq.srqn, sizeof (__u32))) {
			err = -EFAULT;
			goto err_wrid;
		}

	init_attr->attr.max_wr = srq->msrq.max - 1;

	return &srq->ibsrq;

err_wrid:
	if (pd->uobject)
		mlx4_ib_db_unmap_user(to_mucontext(pd->uobject->context), &srq->db);
	else
		kfree(srq->wrid);

err_mtt:
	mlx4_mtt_cleanup(dev->dev, &srq->mtt);

err_buf:
	if (pd->uobject)
		ib_umem_release(srq->umem);
	else
		mlx4_buf_free(dev->dev, buf_size, &srq->buf);

err_db:
	if (!pd->uobject)
		mlx4_ib_db_free(dev, &srq->db);

err_srq:
	kfree(srq);

	return ERR_PTR(err);
}

int mlx4_ib_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
		       enum ib_srq_attr_mask attr_mask, struct ib_udata *udata)
{
	struct mlx4_ib_dev *dev = to_mdev(ibsrq->device);
	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
	int ret;

	/* We don't support resizing SRQs (yet?) */
	if (attr_mask & IB_SRQ_MAX_WR)
		return -EINVAL;

	if (attr_mask & IB_SRQ_LIMIT) {
		if (attr->srq_limit >= srq->msrq.max)
			return -EINVAL;

		mutex_lock(&srq->mutex);
		ret = mlx4_srq_arm(dev->dev, &srq->msrq, attr->srq_limit);
		mutex_unlock(&srq->mutex);

		if (ret)
			return ret;
	}

	return 0;
}

int mlx4_ib_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
{
	struct mlx4_ib_dev *dev = to_mdev(ibsrq->device);
	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
	int ret;
	int limit_watermark;

	ret = mlx4_srq_query(dev->dev, &srq->msrq, &limit_watermark);
	if (ret)
		return ret;

	srq_attr->srq_limit = limit_watermark;
	srq_attr->max_wr    = srq->msrq.max - 1;
	srq_attr->max_sge   = srq->msrq.max_gs;

	return 0;
}

int mlx4_ib_destroy_srq(struct ib_srq *srq)
{
	struct mlx4_ib_dev *dev = to_mdev(srq->device);
	struct mlx4_ib_srq *msrq = to_msrq(srq);

	mlx4_srq_free(dev->dev, &msrq->msrq);
	mlx4_mtt_cleanup(dev->dev, &msrq->mtt);

	if (srq->uobject) {
		mlx4_ib_db_unmap_user(to_mucontext(srq->uobject->context), &msrq->db);
		ib_umem_release(msrq->umem);
	} else {
		kfree(msrq->wrid);
		mlx4_buf_free(dev->dev, msrq->msrq.max << msrq->msrq.wqe_shift,
			      &msrq->buf);
		mlx4_ib_db_free(dev, &msrq->db);
	}

	kfree(msrq);

	return 0;
}

void mlx4_ib_free_srq_wqe(struct mlx4_ib_srq *srq, int wqe_index)
{
	struct mlx4_wqe_srq_next_seg *next;

	/* always called with interrupts disabled. */
	spin_lock(&srq->lock);

	next = get_wqe(srq, srq->tail);
	next->next_wqe_index = cpu_to_be16(wqe_index);
	srq->tail = wqe_index;

	spin_unlock(&srq->lock);
}

int mlx4_ib_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
			  struct ib_recv_wr **bad_wr)
{
	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
	struct mlx4_wqe_srq_next_seg *next;
	struct mlx4_wqe_data_seg *scat;
	unsigned long flags;
	int err = 0;
	int nreq;
	int i;

	spin_lock_irqsave(&srq->lock, flags);

	for (nreq = 0; wr; ++nreq, wr = wr->next) {
		if (unlikely(wr->num_sge > srq->msrq.max_gs)) {
			err = -EINVAL;
			*bad_wr = wr;
			break;
		}

		if (unlikely(srq->head == srq->tail)) {
			err = -ENOMEM;
			*bad_wr = wr;
			break;
		}

		srq->wrid[srq->head] = wr->wr_id;

		next      = get_wqe(srq, srq->head);
		srq->head = be16_to_cpu(next->next_wqe_index);
		scat      = (struct mlx4_wqe_data_seg *) (next + 1);

		for (i = 0; i < wr->num_sge; ++i) {
			scat[i].byte_count = cpu_to_be32(wr->sg_list[i].length);
			scat[i].lkey       = cpu_to_be32(wr->sg_list[i].lkey);
			scat[i].addr       = cpu_to_be64(wr->sg_list[i].addr);
		}

		if (i < srq->msrq.max_gs) {
			scat[i].byte_count = 0;
			scat[i].lkey       = cpu_to_be32(MLX4_INVALID_LKEY);
			scat[i].addr       = 0;
		}
	}

	if (likely(nreq)) {
		srq->wqe_ctr += nreq;

		/*
		 * Make sure that descriptors are written before
		 * doorbell record.
		 */
		wmb();

		*srq->db.db = cpu_to_be32(srq->wqe_ctr);
	}

	spin_unlock_irqrestore(&srq->lock, flags);

	return err;
}
Commit	Line	Data
225c7b1f RD	1	/*
	2	* Copyright (c) 2007 Cisco Systems, Inc. All rights reserved.
	3	*
	4	* This software is available to you under a choice of one of two
	5	* licenses. You may choose to be licensed under the terms of the GNU
	6	* General Public License (GPL) Version 2, available from the file
	7	* COPYING in the main directory of this source tree, or the
	8	* OpenIB.org BSD license below:
	9	*
	10	* Redistribution and use in source and binary forms, with or
	11	* without modification, are permitted provided that the following
	12	* conditions are met:
	13	*
	14	* - Redistributions of source code must retain the above
	15	* copyright notice, this list of conditions and the following
	16	* disclaimer.
	17	*
	18	* - Redistributions in binary form must reproduce the above
	19	* copyright notice, this list of conditions and the following
	20	* disclaimer in the documentation and/or other materials
	21	* provided with the distribution.
	22	*
	23	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	24	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	25	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	26	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	27	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	28	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	29	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	30	* SOFTWARE.
	31	*/
	32
	33	#include <linux/mlx4/qp.h>
	34	#include <linux/mlx4/srq.h>
	35
	36	#include "mlx4_ib.h"
	37	#include "user.h"
	38
	39	static void get_wqe(struct mlx4_ib_srq srq, int n)
	40	{
1c69fc2a	41	return mlx4_buf_offset(&srq->buf, n << srq->msrq.wqe_shift);
225c7b1f RD	42	}
	43
	44	static void mlx4_ib_srq_event(struct mlx4_srq *srq, enum mlx4_event type)
	45	{
	46	struct ib_event event;
	47	struct ib_srq *ibsrq = &to_mibsrq(srq)->ibsrq;
	48
	49	if (ibsrq->event_handler) {
	50	event.device = ibsrq->device;
	51	event.element.srq = ibsrq;
	52	switch (type) {
	53	case MLX4_EVENT_TYPE_SRQ_LIMIT:
	54	event.event = IB_EVENT_SRQ_LIMIT_REACHED;
	55	break;
	56	case MLX4_EVENT_TYPE_SRQ_CATAS_ERROR:
	57	event.event = IB_EVENT_SRQ_ERR;
	58	break;
	59	default:
	60	printk(KERN_WARNING "mlx4_ib: Unexpected event type %d "
	61	"on SRQ %06x\n", type, srq->srqn);
	62	return;
	63	}
	64
	65	ibsrq->event_handler(&event, ibsrq->srq_context);
	66	}
	67	}
	68
	69	struct ib_srq mlx4_ib_create_srq(struct ib_pd pd,
	70	struct ib_srq_init_attr *init_attr,
	71	struct ib_udata *udata)
	72	{
	73	struct mlx4_ib_dev *dev = to_mdev(pd->device);
	74	struct mlx4_ib_srq *srq;
	75	struct mlx4_wqe_srq_next_seg *next;
	76	int desc_size;
	77	int buf_size;
	78	int err;
	79	int i;
	80
	81	/* Sanity check SRQ size before proceeding */
	82	if (init_attr->attr.max_wr >= dev->dev->caps.max_srq_wqes \|\|
	83	init_attr->attr.max_sge > dev->dev->caps.max_srq_sge)
	84	return ERR_PTR(-EINVAL);
	85
	86	srq = kmalloc(sizeof *srq, GFP_KERNEL);
	87	if (!srq)
	88	return ERR_PTR(-ENOMEM);
	89
	90	mutex_init(&srq->mutex);
	91	spin_lock_init(&srq->lock);
	92	srq->msrq.max = roundup_pow_of_two(init_attr->attr.max_wr + 1);
	93	srq->msrq.max_gs = init_attr->attr.max_sge;
	94
	95	desc_size = max(32UL,
	96	roundup_pow_of_two(sizeof (struct mlx4_wqe_srq_next_seg) +
	97	srq->msrq.max_gs *
	98	sizeof (struct mlx4_wqe_data_seg)));
	99	srq->msrq.wqe_shift = ilog2(desc_size);
	100
	101	buf_size = srq->msrq.max * desc_size;
	102
	103	if (pd->uobject) {
	104	struct mlx4_ib_create_srq ucmd;
	105
106	if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) {
107	err = -EFAULT;
108	goto err_srq;
109	}
110
111	srq->umem = ib_umem_get(pd->uobject->context, ucmd.buf_addr,
112	buf_size, 0);
113	if (IS_ERR(srq->umem)) {
114	err = PTR_ERR(srq->umem);
115	goto err_srq;
116	}
117
118	err = mlx4_mtt_init(dev->dev, ib_umem_page_count(srq->umem),
119	ilog2(srq->umem->page_size), &srq->mtt);
120	if (err)
121	goto err_buf;
122
123	err = mlx4_ib_umem_write_mtt(dev, &srq->mtt, srq->umem);
124	if (err)
125	goto err_mtt;
126
127	err = mlx4_ib_db_map_user(to_mucontext(pd->uobject->context),
128	ucmd.db_addr, &srq->db);
129	if (err)
130	goto err_mtt;
131	} else {
132	err = mlx4_ib_db_alloc(dev, &srq->db, 0);
133	if (err)
134	goto err_srq;
135
136	*srq->db.db = 0;
137
138	if (mlx4_buf_alloc(dev->dev, buf_size, PAGE_SIZE * 2, &srq->buf)) {
139	err = -ENOMEM;
140	goto err_db;
141	}
142
143	srq->head = 0;
144	srq->tail = srq->msrq.max - 1;
145	srq->wqe_ctr = 0;
146
147	for (i = 0; i < srq->msrq.max; ++i) {
148	next = get_wqe(srq, i);
149	next->next_wqe_index =
150	cpu_to_be16((i + 1) & (srq->msrq.max - 1));
151	}
152
153	err = mlx4_mtt_init(dev->dev, srq->buf.npages, srq->buf.page_shift,
154	&srq->mtt);
155	if (err)
156	goto err_buf;
157
158	err = mlx4_buf_write_mtt(dev->dev, &srq->mtt, &srq->buf);
159	if (err)
160	goto err_mtt;
161
162	srq->wrid = kmalloc(srq->msrq.max * sizeof (u64), GFP_KERNEL);
163	if (!srq->wrid) {
164	err = -ENOMEM;
165	goto err_mtt;
166	}
167	}
168
169	err = mlx4_srq_alloc(dev->dev, to_mpd(pd)->pdn, &srq->mtt,
170	srq->db.dma, &srq->msrq);
171	if (err)
172	goto err_wrid;
173
174	srq->msrq.event = mlx4_ib_srq_event;
175
176	if (pd->uobject)
177	if (ib_copy_to_udata(udata, &srq->msrq.srqn, sizeof (__u32))) {
178	err = -EFAULT;
179	goto err_wrid;
180	}
181
182	init_attr->attr.max_wr = srq->msrq.max - 1;
183
184	return &srq->ibsrq;
185
186	err_wrid:
187	if (pd->uobject)
188	mlx4_ib_db_unmap_user(to_mucontext(pd->uobject->context), &srq->db);
189	else
190	kfree(srq->wrid);
191
192	err_mtt:
193	mlx4_mtt_cleanup(dev->dev, &srq->mtt);
194
195	err_buf:
196	if (pd->uobject)
197	ib_umem_release(srq->umem);
198	else
199	mlx4_buf_free(dev->dev, buf_size, &srq->buf);
200
201	err_db:
202	if (!pd->uobject)
203	mlx4_ib_db_free(dev, &srq->db);
204
205	err_srq:
206	kfree(srq);
207
208	return ERR_PTR(err);
209	}
210
211	int mlx4_ib_modify_srq(struct ib_srq ibsrq, struct ib_srq_attr attr,
212	enum ib_srq_attr_mask attr_mask, struct ib_udata *udata)
213	{
214	struct mlx4_ib_dev *dev = to_mdev(ibsrq->device);
215	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
216	int ret;
217
218	/* We don't support resizing SRQs (yet?) */
219	if (attr_mask & IB_SRQ_MAX_WR)
220	return -EINVAL;
221
222	if (attr_mask & IB_SRQ_LIMIT) {
223	if (attr->srq_limit >= srq->msrq.max)
224	return -EINVAL;
225
226	mutex_lock(&srq->mutex);
227	ret = mlx4_srq_arm(dev->dev, &srq->msrq, attr->srq_limit);
228	mutex_unlock(&srq->mutex);
229
230	if (ret)
231	return ret;
232	}
233
234	return 0;
235	}
236
65541cb7 JM	237	int mlx4_ib_query_srq(struct ib_srq ibsrq, struct ib_srq_attr srq_attr)
	238	{
	239	struct mlx4_ib_dev *dev = to_mdev(ibsrq->device);
	240	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
	241	int ret;
	242	int limit_watermark;
	243
	244	ret = mlx4_srq_query(dev->dev, &srq->msrq, &limit_watermark);
	245	if (ret)
	246	return ret;
	247
d7dc3ccb	248	srq_attr->srq_limit = limit_watermark;
65541cb7 JM	249	srq_attr->max_wr = srq->msrq.max - 1;
	250	srq_attr->max_sge = srq->msrq.max_gs;
	251
	252	return 0;
	253	}
	254
225c7b1f RD	255	int mlx4_ib_destroy_srq(struct ib_srq *srq)
	256	{
	257	struct mlx4_ib_dev *dev = to_mdev(srq->device);
	258	struct mlx4_ib_srq *msrq = to_msrq(srq);
	259
	260	mlx4_srq_free(dev->dev, &msrq->msrq);
	261	mlx4_mtt_cleanup(dev->dev, &msrq->mtt);
	262
	263	if (srq->uobject) {
	264	mlx4_ib_db_unmap_user(to_mucontext(srq->uobject->context), &msrq->db);
	265	ib_umem_release(msrq->umem);
	266	} else {
	267	kfree(msrq->wrid);
	268	mlx4_buf_free(dev->dev, msrq->msrq.max << msrq->msrq.wqe_shift,
	269	&msrq->buf);
	270	mlx4_ib_db_free(dev, &msrq->db);
	271	}
	272
	273	kfree(msrq);
	274
	275	return 0;
	276	}
	277
	278	void mlx4_ib_free_srq_wqe(struct mlx4_ib_srq *srq, int wqe_index)
	279	{
	280	struct mlx4_wqe_srq_next_seg *next;
	281
	282	/* always called with interrupts disabled. */
	283	spin_lock(&srq->lock);
	284
	285	next = get_wqe(srq, srq->tail);
	286	next->next_wqe_index = cpu_to_be16(wqe_index);
	287	srq->tail = wqe_index;
	288
	289	spin_unlock(&srq->lock);
	290	}
	291
	292	int mlx4_ib_post_srq_recv(struct ib_srq ibsrq, struct ib_recv_wr wr,
	293	struct ib_recv_wr **bad_wr)
	294	{
	295	struct mlx4_ib_srq *srq = to_msrq(ibsrq);
	296	struct mlx4_wqe_srq_next_seg *next;
	297	struct mlx4_wqe_data_seg *scat;
	298	unsigned long flags;
	299	int err = 0;
	300	int nreq;
	301	int i;
	302
	303	spin_lock_irqsave(&srq->lock, flags);
	304
	305	for (nreq = 0; wr; ++nreq, wr = wr->next) {
	306	if (unlikely(wr->num_sge > srq->msrq.max_gs)) {
	307	err = -EINVAL;
	308	*bad_wr = wr;
	309	break;
	310	}
	311
56a8c8b6 RD	312	if (unlikely(srq->head == srq->tail)) {
	313	err = -ENOMEM;
	314	*bad_wr = wr;
	315	break;
	316	}
	317
225c7b1f RD	318	srq->wrid[srq->head] = wr->wr_id;
	319
	320	next = get_wqe(srq, srq->head);
	321	srq->head = be16_to_cpu(next->next_wqe_index);
	322	scat = (struct mlx4_wqe_data_seg *) (next + 1);
	323
	324	for (i = 0; i < wr->num_sge; ++i) {
	325	scat[i].byte_count = cpu_to_be32(wr->sg_list[i].length);
	326	scat[i].lkey = cpu_to_be32(wr->sg_list[i].lkey);
	327	scat[i].addr = cpu_to_be64(wr->sg_list[i].addr);
	328	}
	329
	330	if (i < srq->msrq.max_gs) {
	331	scat[i].byte_count = 0;
	332	scat[i].lkey = cpu_to_be32(MLX4_INVALID_LKEY);
	333	scat[i].addr = 0;
	334	}
	335	}
	336
	337	if (likely(nreq)) {
	338	srq->wqe_ctr += nreq;
	339
	340	/*
	341	* Make sure that descriptors are written before
	342	* doorbell record.
	343	*/
	344	wmb();
	345
	346	*srq->db.db = cpu_to_be32(srq->wqe_ctr);
	347	}
	348
	349	spin_unlock_irqrestore(&srq->lock, flags);
	350
	351	return err;
	352	}