providers/mlx5/srq.c - linux-rdma/rdma-core - Git at Google

 /*
  * Copyright (c) 2012 Mellanox Technologies, 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 <config.h>

 #include <stdlib.h>
 #include <pthread.h>
 #include <string.h>
 #include <errno.h>

 #include "mlx5.h"
 #include "wqe.h"

 static void *get_wqe(struct mlx5_srq *srq, int n)
 {
 	return srq->buf.buf + (n << srq->wqe_shift);
 }

 int mlx5_copy_to_recv_srq(struct mlx5_srq *srq, int idx, void *buf, int size)
 {
 	struct mlx5_wqe_srq_next_seg *next;
 	struct mlx5_wqe_data_seg *scat;
 	int copy;
 	int i;
 	int max = 1 << (srq->wqe_shift - 4);

 	next = get_wqe(srq, idx);
 	scat = (struct mlx5_wqe_data_seg *) (next + 1);

 	for (i = 0; i < max; ++i) {
 		copy = min_t(long, size, be32toh(scat->byte_count));
 		memcpy((void *)(unsigned long)be64toh(scat->addr), buf, copy);
 		size -= copy;
 		if (size <= 0)
 			return IBV_WC_SUCCESS;

 		buf += copy;
 		++scat;
 	}
 	return IBV_WC_LOC_LEN_ERR;
 }

 void mlx5_free_srq_wqe(struct mlx5_srq *srq, int ind)
 {
 	struct mlx5_wqe_srq_next_seg *next;

 	mlx5_spin_lock(&srq->lock);

 	next = get_wqe(srq, srq->tail);
 	next->next_wqe_index = htobe16(ind);
 	srq->tail = ind;

 	mlx5_spin_unlock(&srq->lock);
 }

 /* Take an index and put it last in wait queue */
 static void srq_put_in_waitq(struct mlx5_srq *srq, int ind)
 {
 	struct mlx5_wqe_srq_next_seg *waitq_tail;

 	waitq_tail = get_wqe(srq, srq->waitq_tail);
 	waitq_tail->next_wqe_index = htobe16(ind);
 	srq->waitq_tail = ind;
 }

 /* Take first in wait queue and put in tail of SRQ */
 static void srq_get_from_waitq(struct mlx5_srq *srq)
 {
 	struct mlx5_wqe_srq_next_seg *tail;
 	struct mlx5_wqe_srq_next_seg *waitq_head;

 	tail = get_wqe(srq, srq->tail);
 	waitq_head = get_wqe(srq, srq->waitq_head);

 	tail->next_wqe_index = htobe16(srq->waitq_head);
 	srq->tail = srq->waitq_head;
 	srq->waitq_head = be16toh(waitq_head->next_wqe_index);
 }

 /* Put the given WQE that is in SW ownership at the end of the wait queue.
  * Take a WQE from the wait queue and add it to WQEs in SW ownership instead.
  */
 bool srq_cooldown_wqe(struct mlx5_srq *srq, int ind)
 {
 	if (!srq_has_waitq(srq))
 		return false;

 	srq_put_in_waitq(srq, ind);
 	srq_get_from_waitq(srq);
 	return true;
 }

 /* Post a WQE internally, based on a previous application post.
  * Copy a given WQE's data segments to the SRQ head, advance the head
  * and ring the HW doorbell.
  */
 static void srq_repost(struct mlx5_srq *srq, int ind)
 {
 	struct mlx5_wqe_srq_next_seg *src, *dst;
 	struct mlx5_wqe_data_seg *src_scat, *dst_scat;
 	int i;

 	srq->wrid[srq->head] = srq->wrid[ind];

 	src = get_wqe(srq, ind);
 	dst = get_wqe(srq, srq->head);
 	src_scat = (struct mlx5_wqe_data_seg *)(src + 1);
 	dst_scat = (struct mlx5_wqe_data_seg *)(dst + 1);

 	for (i = 0; i < srq->max_gs; ++i) {
 		dst_scat[i] = src_scat[i];

 		if (dst_scat[i].lkey == htobe32(MLX5_INVALID_LKEY))
 			break;
 	}

 	srq->head = be16toh(dst->next_wqe_index);
 	srq->counter++;
 	/* Flush descriptors */
 	udma_to_device_barrier();
 	*srq->db = htobe32(srq->counter);
 }

 void mlx5_complete_odp_fault(struct mlx5_srq *srq, int ind)
 {
 	mlx5_spin_lock(&srq->lock);

 	if (!srq_cooldown_wqe(srq, ind)) {
 		struct mlx5_wqe_srq_next_seg *tail = get_wqe(srq, srq->tail);

 		/* Without a wait queue put the page-faulted wqe
 		 * back in SRQ tail. The repost is still possible but
 		 * the risk of overriding the page-faulted WQE with a future
 		 * post_srq_recv() is now higher.
 		 */
 		tail->next_wqe_index = htobe16(ind);
 		srq->tail = ind;
 	}

 	srq_repost(srq, ind);

 	mlx5_spin_unlock(&srq->lock);
 }

 int mlx5_post_srq_recv(struct ibv_srq *ibsrq,
 		       struct ibv_recv_wr *wr,
 		       struct ibv_recv_wr **bad_wr)
 {
 	struct mlx5_srq *srq = to_msrq(ibsrq);
 	struct mlx5_wqe_srq_next_seg *next;
 	struct mlx5_wqe_data_seg *scat;
 	int err = 0;
 	int nreq;
 	int i;

 	mlx5_spin_lock(&srq->lock);

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

 		if (srq->head == srq->tail) {
 			/* SRQ is full*/
 			err = ENOMEM;
 			*bad_wr = wr;
 			break;
 		}

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

 		next      = get_wqe(srq, srq->head);
 		srq->head = be16toh(next->next_wqe_index);
 		scat      = (struct mlx5_wqe_data_seg *) (next + 1);

 		for (i = 0; i < wr->num_sge; ++i) {
 			scat[i].byte_count = htobe32(wr->sg_list[i].length);
 			scat[i].lkey       = htobe32(wr->sg_list[i].lkey);
 			scat[i].addr       = htobe64(wr->sg_list[i].addr);
 		}

 		if (i < srq->max_gs) {
 			scat[i].byte_count = 0;
 			scat[i].lkey       = htobe32(MLX5_INVALID_LKEY);
 			scat[i].addr       = 0;
 		}
 	}

 	if (nreq) {
 		srq->counter += nreq;

 		/*
 		 * Make sure that descriptors are written before
 		 * we write doorbell record.
 		 */
 		udma_to_device_barrier();

 		*srq->db = htobe32(srq->counter);
 	}

 	mlx5_spin_unlock(&srq->lock);

 	return err;
 }

 /* Build a linked list on an array of SRQ WQEs.
  * Since WQEs are always added to the tail and taken from the head
  * it doesn't matter where the last WQE points to.
  */
 static void set_srq_buf_ll(struct mlx5_srq *srq, int start, int end)
 {
 	struct mlx5_wqe_srq_next_seg *next;
 	int i;

 	for (i = start; i < end; ++i) {
 		next = get_wqe(srq, i);
 		next->next_wqe_index = htobe16(i + 1);
 	}
 }

 int mlx5_alloc_srq_buf(struct ibv_context *context, struct mlx5_srq *srq,
 		       uint32_t max_wr, struct ibv_pd *pd)
 {
 	int size;
 	int buf_size;
 	struct mlx5_context	   *ctx;
 	uint32_t orig_max_wr = max_wr;
 	bool have_wq = true;
 	enum mlx5_alloc_type alloc_type;

 	ctx = to_mctx(context);

 	if (srq->max_gs < 0) {
 		errno = EINVAL;
 		return -1;
 	}

 	/* At first, try to allocate more WQEs than requested so the extra will
 	 * be used for the wait queue.
 	 */
 	max_wr = orig_max_wr * 2 + 1;

 	if (max_wr > ctx->max_srq_recv_wr) {
 		/* Device limits are smaller than required
 		 * to provide a wait queue, continue without.
 		 */
 		max_wr = orig_max_wr + 1;
 		have_wq = false;
 	}

 	size = sizeof(struct mlx5_wqe_srq_next_seg) +
 		srq->max_gs * sizeof(struct mlx5_wqe_data_seg);
 	size = max(32, size);

 	size = roundup_pow_of_two(size);

 	if (size > ctx->max_recv_wr) {
 		errno = EINVAL;
 		return -1;
 	}
 	srq->max_gs = (size - sizeof(struct mlx5_wqe_srq_next_seg)) /
 		sizeof(struct mlx5_wqe_data_seg);

 	srq->wqe_shift = ilog32(size - 1);

 	srq->max = align_queue_size(max_wr);
 	buf_size = srq->max * size;

 	mlx5_get_alloc_type(ctx, pd, MLX5_SRQ_PREFIX, &alloc_type,
 			    MLX5_ALLOC_TYPE_ANON);

 	if (alloc_type == MLX5_ALLOC_TYPE_CUSTOM) {
 		srq->buf.mparent_domain = to_mparent_domain(pd);
 		srq->buf.req_alignment = to_mdev(context->device)->page_size;
 		srq->buf.resource_type = MLX5DV_RES_TYPE_SRQ;
 	}

 	if (mlx5_alloc_prefered_buf(ctx,
 				    &srq->buf, buf_size,
 				    to_mdev(context->device)->page_size,
 				    alloc_type,
 				    MLX5_SRQ_PREFIX))
 		return -1;

 	if (srq->buf.type != MLX5_ALLOC_TYPE_CUSTOM)
 		memset(srq->buf.buf, 0, buf_size);

 	srq->head = 0;
 	srq->tail = align_queue_size(orig_max_wr + 1) - 1;
 	if (have_wq)  {
 		srq->waitq_head = srq->tail + 1;
 		srq->waitq_tail = srq->max - 1;
 	} else {
 		srq->waitq_head = -1;
 		srq->waitq_tail = -1;
 	}

 	srq->wrid = malloc(srq->max * sizeof(*srq->wrid));
 	if (!srq->wrid) {
 		mlx5_free_actual_buf(ctx, &srq->buf);
 		return -1;
 	}

 	/*
 	 * Now initialize the SRQ buffer so that all of the WQEs are
 	 * linked into the list of free WQEs.
 	 */

 	set_srq_buf_ll(srq, srq->head, srq->tail);
 	if (have_wq)
 		set_srq_buf_ll(srq, srq->waitq_head, srq->waitq_tail);

 	return 0;
 }

 struct mlx5_srq *mlx5_find_srq(struct mlx5_context *ctx, uint32_t srqn)
 {
 	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

 	if (ctx->srq_table[tind].refcnt)
 		return ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK];
 	else
 		return NULL;
 }

 int mlx5_store_srq(struct mlx5_context *ctx, uint32_t srqn,
 		   struct mlx5_srq *srq)
 {
 	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

 	if (!ctx->srq_table[tind].refcnt) {
 		ctx->srq_table[tind].table = calloc(MLX5_SRQ_TABLE_MASK + 1,
 						   sizeof(struct mlx5_srq *));
 		if (!ctx->srq_table[tind].table)
 			return -1;
 	}

 	++ctx->srq_table[tind].refcnt;
 	ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK] = srq;
 	return 0;
 }

 void mlx5_clear_srq(struct mlx5_context *ctx, uint32_t srqn)
 {
 	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

 	if (!--ctx->srq_table[tind].refcnt)
 		free(ctx->srq_table[tind].table);
 	else
 		ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK] = NULL;
 }
	/*
	* Copyright (c) 2012 Mellanox Technologies, 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 <config.h>

	#include <stdlib.h>
	#include <pthread.h>
	#include <string.h>
	#include <errno.h>

	#include "mlx5.h"
	#include "wqe.h"

	static void get_wqe(struct mlx5_srq srq, int n)
	{
	return srq->buf.buf + (n << srq->wqe_shift);
	}

	int mlx5_copy_to_recv_srq(struct mlx5_srq srq, int idx, void buf, int size)
	{
	struct mlx5_wqe_srq_next_seg *next;
	struct mlx5_wqe_data_seg *scat;
	int copy;
	int i;
	int max = 1 << (srq->wqe_shift - 4);

	next = get_wqe(srq, idx);
	scat = (struct mlx5_wqe_data_seg *) (next + 1);

	for (i = 0; i < max; ++i) {
	copy = min_t(long, size, be32toh(scat->byte_count));
	memcpy((void *)(unsigned long)be64toh(scat->addr), buf, copy);
	size -= copy;
	if (size <= 0)
	return IBV_WC_SUCCESS;

	buf += copy;
	++scat;
	}
	return IBV_WC_LOC_LEN_ERR;
	}

	void mlx5_free_srq_wqe(struct mlx5_srq *srq, int ind)
	{
	struct mlx5_wqe_srq_next_seg *next;

	mlx5_spin_lock(&srq->lock);

	next = get_wqe(srq, srq->tail);
	next->next_wqe_index = htobe16(ind);
	srq->tail = ind;

	mlx5_spin_unlock(&srq->lock);
	}

	/* Take an index and put it last in wait queue */
	static void srq_put_in_waitq(struct mlx5_srq *srq, int ind)
	{
	struct mlx5_wqe_srq_next_seg *waitq_tail;

	waitq_tail = get_wqe(srq, srq->waitq_tail);
	waitq_tail->next_wqe_index = htobe16(ind);
	srq->waitq_tail = ind;
	}

	/* Take first in wait queue and put in tail of SRQ */
	static void srq_get_from_waitq(struct mlx5_srq *srq)
	{
	struct mlx5_wqe_srq_next_seg *tail;
	struct mlx5_wqe_srq_next_seg *waitq_head;

	tail = get_wqe(srq, srq->tail);
	waitq_head = get_wqe(srq, srq->waitq_head);

	tail->next_wqe_index = htobe16(srq->waitq_head);
	srq->tail = srq->waitq_head;
	srq->waitq_head = be16toh(waitq_head->next_wqe_index);
	}

	/* Put the given WQE that is in SW ownership at the end of the wait queue.
	* Take a WQE from the wait queue and add it to WQEs in SW ownership instead.
	*/
	bool srq_cooldown_wqe(struct mlx5_srq *srq, int ind)
	{
	if (!srq_has_waitq(srq))
	return false;

	srq_put_in_waitq(srq, ind);
	srq_get_from_waitq(srq);
	return true;
	}

	/* Post a WQE internally, based on a previous application post.
	* Copy a given WQE's data segments to the SRQ head, advance the head
	* and ring the HW doorbell.
	*/
	static void srq_repost(struct mlx5_srq *srq, int ind)
	{
	struct mlx5_wqe_srq_next_seg src, dst;
	struct mlx5_wqe_data_seg src_scat, dst_scat;
	int i;

	srq->wrid[srq->head] = srq->wrid[ind];

	src = get_wqe(srq, ind);
	dst = get_wqe(srq, srq->head);
	src_scat = (struct mlx5_wqe_data_seg *)(src + 1);
	dst_scat = (struct mlx5_wqe_data_seg *)(dst + 1);

	for (i = 0; i < srq->max_gs; ++i) {
	dst_scat[i] = src_scat[i];

	if (dst_scat[i].lkey == htobe32(MLX5_INVALID_LKEY))
	break;
	}

	srq->head = be16toh(dst->next_wqe_index);
	srq->counter++;
	/* Flush descriptors */
	udma_to_device_barrier();
	*srq->db = htobe32(srq->counter);
	}

	void mlx5_complete_odp_fault(struct mlx5_srq *srq, int ind)
	{
	mlx5_spin_lock(&srq->lock);

	if (!srq_cooldown_wqe(srq, ind)) {
	struct mlx5_wqe_srq_next_seg *tail = get_wqe(srq, srq->tail);

	/* Without a wait queue put the page-faulted wqe
	* back in SRQ tail. The repost is still possible but
	* the risk of overriding the page-faulted WQE with a future
	* post_srq_recv() is now higher.
	*/
	tail->next_wqe_index = htobe16(ind);
	srq->tail = ind;
	}

	srq_repost(srq, ind);

	mlx5_spin_unlock(&srq->lock);
	}

	int mlx5_post_srq_recv(struct ibv_srq *ibsrq,
	struct ibv_recv_wr *wr,
	struct ibv_recv_wr **bad_wr)
	{
	struct mlx5_srq *srq = to_msrq(ibsrq);
	struct mlx5_wqe_srq_next_seg *next;
	struct mlx5_wqe_data_seg *scat;
	int err = 0;
	int nreq;
	int i;

	mlx5_spin_lock(&srq->lock);

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

	if (srq->head == srq->tail) {
	/* SRQ is full*/
	err = ENOMEM;
	*bad_wr = wr;
	break;
	}

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

	next = get_wqe(srq, srq->head);
	srq->head = be16toh(next->next_wqe_index);
	scat = (struct mlx5_wqe_data_seg *) (next + 1);

	for (i = 0; i < wr->num_sge; ++i) {
	scat[i].byte_count = htobe32(wr->sg_list[i].length);
	scat[i].lkey = htobe32(wr->sg_list[i].lkey);
	scat[i].addr = htobe64(wr->sg_list[i].addr);
	}

	if (i < srq->max_gs) {
	scat[i].byte_count = 0;
	scat[i].lkey = htobe32(MLX5_INVALID_LKEY);
	scat[i].addr = 0;
	}
	}

	if (nreq) {
	srq->counter += nreq;

	/*
	* Make sure that descriptors are written before
	* we write doorbell record.
	*/
	udma_to_device_barrier();

	*srq->db = htobe32(srq->counter);
	}

	mlx5_spin_unlock(&srq->lock);

	return err;
	}

	/* Build a linked list on an array of SRQ WQEs.
	* Since WQEs are always added to the tail and taken from the head
	* it doesn't matter where the last WQE points to.
	*/
	static void set_srq_buf_ll(struct mlx5_srq *srq, int start, int end)
	{
	struct mlx5_wqe_srq_next_seg *next;
	int i;

	for (i = start; i < end; ++i) {
	next = get_wqe(srq, i);
	next->next_wqe_index = htobe16(i + 1);
	}
	}

	int mlx5_alloc_srq_buf(struct ibv_context context, struct mlx5_srq srq,
	uint32_t max_wr, struct ibv_pd *pd)
	{
	int size;
	int buf_size;
	struct mlx5_context *ctx;
	uint32_t orig_max_wr = max_wr;
	bool have_wq = true;
	enum mlx5_alloc_type alloc_type;

	ctx = to_mctx(context);

	if (srq->max_gs < 0) {
	errno = EINVAL;
	return -1;
	}

	/* At first, try to allocate more WQEs than requested so the extra will
	* be used for the wait queue.
	*/
	max_wr = orig_max_wr * 2 + 1;

	if (max_wr > ctx->max_srq_recv_wr) {
	/* Device limits are smaller than required
	* to provide a wait queue, continue without.
	*/
	max_wr = orig_max_wr + 1;
	have_wq = false;
	}

	size = sizeof(struct mlx5_wqe_srq_next_seg) +
	srq->max_gs * sizeof(struct mlx5_wqe_data_seg);
	size = max(32, size);

	size = roundup_pow_of_two(size);

	if (size > ctx->max_recv_wr) {
	errno = EINVAL;
	return -1;
	}
	srq->max_gs = (size - sizeof(struct mlx5_wqe_srq_next_seg)) /
	sizeof(struct mlx5_wqe_data_seg);

	srq->wqe_shift = ilog32(size - 1);

	srq->max = align_queue_size(max_wr);
	buf_size = srq->max * size;

	mlx5_get_alloc_type(ctx, pd, MLX5_SRQ_PREFIX, &alloc_type,
	MLX5_ALLOC_TYPE_ANON);

	if (alloc_type == MLX5_ALLOC_TYPE_CUSTOM) {
	srq->buf.mparent_domain = to_mparent_domain(pd);
	srq->buf.req_alignment = to_mdev(context->device)->page_size;
	srq->buf.resource_type = MLX5DV_RES_TYPE_SRQ;
	}

	if (mlx5_alloc_prefered_buf(ctx,
	&srq->buf, buf_size,
	to_mdev(context->device)->page_size,
	alloc_type,
	MLX5_SRQ_PREFIX))
	return -1;

	if (srq->buf.type != MLX5_ALLOC_TYPE_CUSTOM)
	memset(srq->buf.buf, 0, buf_size);

	srq->head = 0;
	srq->tail = align_queue_size(orig_max_wr + 1) - 1;
	if (have_wq) {
	srq->waitq_head = srq->tail + 1;
	srq->waitq_tail = srq->max - 1;
	} else {
	srq->waitq_head = -1;
	srq->waitq_tail = -1;
	}

	srq->wrid = malloc(srq->max * sizeof(*srq->wrid));
	if (!srq->wrid) {
	mlx5_free_actual_buf(ctx, &srq->buf);
	return -1;
	}

	/*
	* Now initialize the SRQ buffer so that all of the WQEs are
	* linked into the list of free WQEs.
	*/

	set_srq_buf_ll(srq, srq->head, srq->tail);
	if (have_wq)
	set_srq_buf_ll(srq, srq->waitq_head, srq->waitq_tail);

	return 0;
	}

	struct mlx5_srq mlx5_find_srq(struct mlx5_context ctx, uint32_t srqn)
	{
	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

	if (ctx->srq_table[tind].refcnt)
	return ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK];
	else
	return NULL;
	}

	int mlx5_store_srq(struct mlx5_context *ctx, uint32_t srqn,
	struct mlx5_srq *srq)
	{
	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

	if (!ctx->srq_table[tind].refcnt) {
	ctx->srq_table[tind].table = calloc(MLX5_SRQ_TABLE_MASK + 1,
	sizeof(struct mlx5_srq *));
	if (!ctx->srq_table[tind].table)
	return -1;
	}

	++ctx->srq_table[tind].refcnt;
	ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK] = srq;
	return 0;
	}

	void mlx5_clear_srq(struct mlx5_context *ctx, uint32_t srqn)
	{
	int tind = srqn >> MLX5_SRQ_TABLE_SHIFT;

	if (!--ctx->srq_table[tind].refcnt)
	free(ctx->srq_table[tind].table);
	else
	ctx->srq_table[tind].table[srqn & MLX5_SRQ_TABLE_MASK] = NULL;
	}