diff mbox

[09/24] ibtrs: server: main functionality

Message ID 20180202140904.2017-10-roman.penyaev@profitbricks.com (mailing list archive)
State New, archived
Headers show

Commit Message

Roman Pen Feb. 2, 2018, 2:08 p.m. UTC
This is main functionality of ibtrs-server module, which accepts
set of RDMA connections (so called IBTRS session), creates/destroys
sysfs entries associated with IBTRS session and notifies upper layer
(user of IBTRS API) about RDMA requests or link events.

Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Signed-off-by: Danil Kipnis <danil.kipnis@profitbricks.com>
Cc: Jack Wang <jinpu.wang@profitbricks.com>
---
 drivers/infiniband/ulp/ibtrs/ibtrs-srv.c | 1811 ++++++++++++++++++++++++++++++
 1 file changed, 1811 insertions(+)

Comments

Sagi Grimberg Feb. 5, 2018, 11:29 a.m. UTC | #1
Hi Roman,

Some comments below.

On 02/02/2018 04:08 PM, Roman Pen wrote:
> This is main functionality of ibtrs-server module, which accepts
> set of RDMA connections (so called IBTRS session), creates/destroys
> sysfs entries associated with IBTRS session and notifies upper layer
> (user of IBTRS API) about RDMA requests or link events.
> 
> Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
> Signed-off-by: Danil Kipnis <danil.kipnis@profitbricks.com>
> Cc: Jack Wang <jinpu.wang@profitbricks.com>
> ---
>   drivers/infiniband/ulp/ibtrs/ibtrs-srv.c | 1811 ++++++++++++++++++++++++++++++
>   1 file changed, 1811 insertions(+)
> 
> diff --git a/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
> new file mode 100644
> index 000000000000..0d1fc08bd821
> --- /dev/null
> +++ b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
> @@ -0,0 +1,1811 @@
> +/*
> + * InfiniBand Transport Layer
> + *
> + * Copyright (c) 2014 - 2017 ProfitBricks GmbH. All rights reserved.
> + * Authors: Fabian Holler <mail@fholler.de>
> + *          Jack Wang <jinpu.wang@profitbricks.com>
> + *          Kleber Souza <kleber.souza@profitbricks.com>
> + *          Danil Kipnis <danil.kipnis@profitbricks.com>
> + *          Roman Penyaev <roman.penyaev@profitbricks.com>
> + *          Milind Dumbare <Milind.dumbare@gmail.com>
> + *
> + * Copyright (c) 2017 - 2018 ProfitBricks GmbH. All rights reserved.
> + * Authors: Danil Kipnis <danil.kipnis@profitbricks.com>
> + *          Roman Penyaev <roman.penyaev@profitbricks.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * 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 for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#undef pr_fmt
> +#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
> +
> +#include <linux/module.h>
> +#include <linux/mempool.h>
> +
> +#include "ibtrs-srv.h"
> +#include "ibtrs-log.h"
> +
> +MODULE_AUTHOR("ibnbd@profitbricks.com");
> +MODULE_DESCRIPTION("IBTRS Server");
> +MODULE_VERSION(IBTRS_VER_STRING);
> +MODULE_LICENSE("GPL");
> +
> +#define DEFAULT_MAX_IO_SIZE_KB 128
> +#define DEFAULT_MAX_IO_SIZE (DEFAULT_MAX_IO_SIZE_KB * 1024)
> +#define MAX_REQ_SIZE PAGE_SIZE
> +#define MAX_SG_COUNT ((MAX_REQ_SIZE - sizeof(struct ibtrs_msg_rdma_read)) \
> +		      / sizeof(struct ibtrs_sg_desc))
> +
> +static int max_io_size = DEFAULT_MAX_IO_SIZE;
> +static int rcv_buf_size = DEFAULT_MAX_IO_SIZE + MAX_REQ_SIZE;
> +
> +static int max_io_size_set(const char *val, const struct kernel_param *kp)
> +{
> +	int err, ival;
> +
> +	err = kstrtoint(val, 0, &ival);
> +	if (err)
> +		return err;
> +
> +	if (ival < 4096 || ival + MAX_REQ_SIZE > (4096 * 1024) ||
> +	    (ival + MAX_REQ_SIZE) % 512 != 0) {
> +		pr_err("Invalid max io size value %d, has to be"
> +		       " > %d, < %d\n", ival, 4096, 4194304);
> +		return -EINVAL;
> +	}
> +
> +	max_io_size = ival;
> +	rcv_buf_size = max_io_size + MAX_REQ_SIZE;
> +	pr_info("max io size changed to %d\n", ival);
> +
> +	return 0;
> +}
> +
> +static const struct kernel_param_ops max_io_size_ops = {
> +	.set		= max_io_size_set,
> +	.get		= param_get_int,
> +};
> +module_param_cb(max_io_size, &max_io_size_ops, &max_io_size, 0444);
> +MODULE_PARM_DESC(max_io_size,
> +		 "Max size for each IO request, when change the unit is in byte"
> +		 " (default: " __stringify(DEFAULT_MAX_IO_SIZE_KB) "KB)");
> +
> +#define DEFAULT_SESS_QUEUE_DEPTH 512
> +static int sess_queue_depth = DEFAULT_SESS_QUEUE_DEPTH;
> +module_param_named(sess_queue_depth, sess_queue_depth, int, 0444);
> +MODULE_PARM_DESC(sess_queue_depth,
> +		 "Number of buffers for pending I/O requests to allocate"
> +		 " per session. Maximum: " __stringify(MAX_SESS_QUEUE_DEPTH)
> +		 " (default: " __stringify(DEFAULT_SESS_QUEUE_DEPTH) ")");
> +
> +/* We guarantee to serve 10 paths at least */
> +#define CHUNK_POOL_SIZE (DEFAULT_SESS_QUEUE_DEPTH * 10)
> +static mempool_t *chunk_pool;
> +
> +static int retry_count = 7;
> +
> +static int retry_count_set(const char *val, const struct kernel_param *kp)
> +{
> +	int err, ival;
> +
> +	err = kstrtoint(val, 0, &ival);
> +	if (err)
> +		return err;
> +
> +	if (ival < MIN_RTR_CNT || ival > MAX_RTR_CNT) {
> +		pr_err("Invalid retry count value %d, has to be"
> +		       " > %d, < %d\n", ival, MIN_RTR_CNT, MAX_RTR_CNT);
> +		return -EINVAL;
> +	}
> +
> +	retry_count = ival;
> +	pr_info("QP retry count changed to %d\n", ival);
> +
> +	return 0;
> +}
> +
> +static const struct kernel_param_ops retry_count_ops = {
> +	.set		= retry_count_set,
> +	.get		= param_get_int,
> +};
> +module_param_cb(retry_count, &retry_count_ops, &retry_count, 0644);
> +
> +MODULE_PARM_DESC(retry_count, "Number of times to send the message if the"
> +		 " remote side didn't respond with Ack or Nack (default: 3,"
> +		 " min: " __stringify(MIN_RTR_CNT) ", max: "
> +		 __stringify(MAX_RTR_CNT) ")");
> +
> +static char cq_affinity_list[256] = "";
> +static cpumask_t cq_affinity_mask = { CPU_BITS_ALL };
> +
> +static void init_cq_affinity(void)
> +{
> +	sprintf(cq_affinity_list, "0-%d", nr_cpu_ids - 1);
> +}
> +
> +static int cq_affinity_list_set(const char *val, const struct kernel_param *kp)
> +{
> +	int ret = 0, len = strlen(val);
> +	cpumask_var_t new_value;
> +
> +	if (!strlen(cq_affinity_list))
> +		init_cq_affinity();
> +
> +	if (len >= sizeof(cq_affinity_list))
> +		return -EINVAL;
> +	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
> +		return -ENOMEM;
> +
> +	ret = cpulist_parse(val, new_value);
> +	if (ret) {
> +		pr_err("Can't set cq_affinity_list \"%s\": %d\n", val,
> +		       ret);
> +		goto free_cpumask;
> +	}
> +
> +	strlcpy(cq_affinity_list, val, sizeof(cq_affinity_list));
> +	*strchrnul(cq_affinity_list, '\n') = '\0';
> +	cpumask_copy(&cq_affinity_mask, new_value);
> +
> +	pr_info("cq_affinity_list changed to %*pbl\n",
> +		cpumask_pr_args(&cq_affinity_mask));
> +free_cpumask:
> +	free_cpumask_var(new_value);
> +	return ret;
> +}
> +
> +static struct kparam_string cq_affinity_list_kparam_str = {
> +	.maxlen	= sizeof(cq_affinity_list),
> +	.string	= cq_affinity_list
> +};
> +
> +static const struct kernel_param_ops cq_affinity_list_ops = {
> +	.set	= cq_affinity_list_set,
> +	.get	= param_get_string,
> +};
> +
> +module_param_cb(cq_affinity_list, &cq_affinity_list_ops,
> +		&cq_affinity_list_kparam_str, 0644);
> +MODULE_PARM_DESC(cq_affinity_list, "Sets the list of cpus to use as cq vectors."
> +		 "(default: use all possible CPUs)");
> +

Can you explain why not using configfs?

> +static void ibtrs_srv_close_work(struct work_struct *work)
> +{
> +	struct ibtrs_srv_sess *sess;
> +	struct ibtrs_srv_ctx *ctx;
> +	struct ibtrs_srv_con *con;
> +	int i;
> +
> +	sess = container_of(work, typeof(*sess), close_work);
> +	ctx = sess->srv->ctx;
> +
> +	ibtrs_srv_destroy_sess_files(sess);
> +	ibtrs_srv_stop_hb(sess);
> +
> +	for (i = 0; i < sess->s.con_num; i++) {
> +		con = to_srv_con(sess->s.con[i]);
> +		if (!con)
> +			continue;
> +
> +		rdma_disconnect(con->c.cm_id);
> +		ib_drain_qp(con->c.qp);
> +	}
> +	/* Wait for all inflights */
> +	ibtrs_srv_wait_ops_ids(sess);
> +
> +	/* Notify upper layer if we are the last path */
> +	ibtrs_srv_sess_down(sess);
> +
> +	unmap_cont_bufs(sess);
> +	ibtrs_srv_free_ops_ids(sess);
> +
> +	for (i = 0; i < sess->s.con_num; i++) {
> +		con = to_srv_con(sess->s.con[i]);
> +		if (!con)
> +			continue;
> +
> +		ibtrs_cq_qp_destroy(&con->c);
> +		rdma_destroy_id(con->c.cm_id);
> +		kfree(con);
> +	}
> +	ibtrs_ib_dev_put(sess->s.ib_dev);
> +
> +	del_path_from_srv(sess);
> +	put_srv(sess->srv);
> +	sess->srv = NULL;
> +	ibtrs_srv_change_state(sess, IBTRS_SRV_CLOSED);
> +
> +	kfree(sess->rdma_addr);
> +	kfree(sess->s.con);
> +	kfree(sess);
> +}
> +
> +static int ibtrs_rdma_do_accept(struct ibtrs_srv_sess *sess,
> +				struct rdma_cm_id *cm_id)
> +{
> +	struct ibtrs_srv *srv = sess->srv;
> +	struct ibtrs_msg_conn_rsp msg;
> +	struct rdma_conn_param param;
> +	int err;
> +
> +	memset(&param, 0, sizeof(param));
> +	param.retry_count = retry_count;
> +	param.rnr_retry_count = 7;
> +	param.private_data = &msg;
> +	param.private_data_len = sizeof(msg);
> +
> +	memset(&msg, 0, sizeof(msg));
> +	msg.magic = cpu_to_le16(IBTRS_MAGIC);
> +	msg.version = cpu_to_le16(IBTRS_VERSION);
> +	msg.errno = 0;
> +	msg.queue_depth = cpu_to_le16(srv->queue_depth);
> +	msg.rkey = cpu_to_le32(sess->s.ib_dev->rkey);

As said, this cannot happen anymore...

> +static struct rdma_cm_id *ibtrs_srv_cm_init(struct ibtrs_srv_ctx *ctx,
> +					    struct sockaddr *addr,
> +					    enum rdma_port_space ps)
> +{
> +	struct rdma_cm_id *cm_id;
> +	int ret;
> +
> +	cm_id = rdma_create_id(&init_net, ibtrs_srv_rdma_cm_handler,
> +			       ctx, ps, IB_QPT_RC);
> +	if (IS_ERR(cm_id)) {
> +		ret = PTR_ERR(cm_id);
> +		pr_err("Creating id for RDMA connection failed, err: %d\n",
> +		       ret);
> +		goto err_out;
> +	}
> +	ret = rdma_bind_addr(cm_id, addr);
> +	if (ret) {
> +		pr_err("Binding RDMA address failed, err: %d\n", ret);
> +		goto err_cm;
> +	}
> +	ret = rdma_listen(cm_id, 64);
> +	if (ret) {
> +		pr_err("Listening on RDMA connection failed, err: %d\n",
> +		       ret);
> +		goto err_cm;
> +	}
> +
> +	switch (addr->sa_family) {
> +	case AF_INET:
> +		pr_debug("listening on port %u\n",
> +			 ntohs(((struct sockaddr_in *)addr)->sin_port));
> +		break;
> +	case AF_INET6:
> +		pr_debug("listening on port %u\n",
> +			 ntohs(((struct sockaddr_in6 *)addr)->sin6_port));
> +		break;
> +	case AF_IB:
> +		pr_debug("listening on service id 0x%016llx\n",
> +			 be64_to_cpu(rdma_get_service_id(cm_id, addr)));
> +		break;
> +	default:
> +		pr_debug("listening on address family %u\n", addr->sa_family);
> +	}

We already have printk that accepts address format...

> +
> +	return cm_id;
> +
> +err_cm:
> +	rdma_destroy_id(cm_id);
> +err_out:
> +
> +	return ERR_PTR(ret);
> +}
> +
> +static int ibtrs_srv_rdma_init(struct ibtrs_srv_ctx *ctx, unsigned int port)
> +{
> +	struct sockaddr_in6 sin = {
> +		.sin6_family	= AF_INET6,
> +		.sin6_addr	= IN6ADDR_ANY_INIT,
> +		.sin6_port	= htons(port),
> +	};
> +	struct sockaddr_ib sib = {
> +		.sib_family			= AF_IB,
> +		.sib_addr.sib_subnet_prefix	= 0ULL,
> +		.sib_addr.sib_interface_id	= 0ULL,
> +		.sib_sid	= cpu_to_be64(RDMA_IB_IP_PS_IB | port),
> +		.sib_sid_mask	= cpu_to_be64(0xffffffffffffffffULL),
> +		.sib_pkey	= cpu_to_be16(0xffff),
> +	};

ipv4?

> +	struct rdma_cm_id *cm_ip, *cm_ib;
> +	int ret;
> +
> +	/*
> +	 * We accept both IPoIB and IB connections, so we need to keep
> +	 * two cm id's, one for each socket type and port space.
> +	 * If the cm initialization of one of the id's fails, we abort
> +	 * everything.
> +	 */
> +	cm_ip = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sin, RDMA_PS_TCP);
> +	if (unlikely(IS_ERR(cm_ip)))
> +		return PTR_ERR(cm_ip);
> +
> +	cm_ib = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sib, RDMA_PS_IB);
> +	if (unlikely(IS_ERR(cm_ib))) {
> +		ret = PTR_ERR(cm_ib);
> +		goto free_cm_ip;
> +	}
> +
> +	ctx->cm_id_ip = cm_ip;
> +	ctx->cm_id_ib = cm_ib;
> +
> +	return 0;
> +
> +free_cm_ip:
> +	rdma_destroy_id(cm_ip);
> +
> +	return ret;
> +}
> +
> +static struct ibtrs_srv_ctx *alloc_srv_ctx(rdma_ev_fn *rdma_ev,
> +					   link_ev_fn *link_ev)
> +{
> +	struct ibtrs_srv_ctx *ctx;
> +
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return NULL;
> +
> +	ctx->rdma_ev = rdma_ev;
> +	ctx->link_ev = link_ev;
> +	mutex_init(&ctx->srv_mutex);
> +	INIT_LIST_HEAD(&ctx->srv_list);
> +
> +	return ctx;
> +}
> +
> +static void free_srv_ctx(struct ibtrs_srv_ctx *ctx)
> +{
> +	WARN_ON(!list_empty(&ctx->srv_list));
> +	kfree(ctx);
> +}
> +
> +struct ibtrs_srv_ctx *ibtrs_srv_open(rdma_ev_fn *rdma_ev, link_ev_fn *link_ev,
> +				     unsigned int port)
> +{
> +	struct ibtrs_srv_ctx *ctx;
> +	int err;
> +
> +	ctx = alloc_srv_ctx(rdma_ev, link_ev);
> +	if (unlikely(!ctx))
> +		return ERR_PTR(-ENOMEM);
> +
> +	err = ibtrs_srv_rdma_init(ctx, port);
> +	if (unlikely(err)) {
> +		free_srv_ctx(ctx);
> +		return ERR_PTR(err);
> +	}
> +	/* Do not let module be unloaded if server context is alive */
> +	__module_get(THIS_MODULE);
> +
> +	return ctx;
> +}
> +EXPORT_SYMBOL(ibtrs_srv_open);
> +
> +void ibtrs_srv_queue_close(struct ibtrs_srv_sess *sess)
> +{
> +	close_sess(sess);
> +}
> +
> +static void close_sess(struct ibtrs_srv_sess *sess)
> +{
> +	enum ibtrs_srv_state old_state;
> +
> +	if (ibtrs_srv_change_state_get_old(sess, IBTRS_SRV_CLOSING,
> +					   &old_state))
> +		queue_work(ibtrs_wq, &sess->close_work);
> +	WARN_ON(sess->state != IBTRS_SRV_CLOSING);
> +}
> +
> +static void close_sessions(struct ibtrs_srv *srv)
> +{
> +	struct ibtrs_srv_sess *sess;
> +
> +	mutex_lock(&srv->paths_mutex);
> +	list_for_each_entry(sess, &srv->paths_list, s.entry)
> +		close_sess(sess);
> +	mutex_unlock(&srv->paths_mutex);
> +}
> +
> +static void close_ctx(struct ibtrs_srv_ctx *ctx)
> +{
> +	struct ibtrs_srv *srv;
> +
> +	mutex_lock(&ctx->srv_mutex);
> +	list_for_each_entry(srv, &ctx->srv_list, ctx_list)
> +		close_sessions(srv);
> +	mutex_unlock(&ctx->srv_mutex);
> +	flush_workqueue(ibtrs_wq);
> +}
> +
> +void ibtrs_srv_close(struct ibtrs_srv_ctx *ctx)
> +{
> +	rdma_destroy_id(ctx->cm_id_ip);
> +	rdma_destroy_id(ctx->cm_id_ib);
> +	close_ctx(ctx);
> +	free_srv_ctx(ctx);
> +	module_put(THIS_MODULE);
> +}
> +EXPORT_SYMBOL(ibtrs_srv_close);
> +
> +static int check_module_params(void)
> +{
> +	if (sess_queue_depth < 1 || sess_queue_depth > MAX_SESS_QUEUE_DEPTH) {
> +		pr_err("Invalid sess_queue_depth parameter value\n");
> +		return -EINVAL;
> +	}
> +
> +	/* check if IB immediate data size is enough to hold the mem_id and the
> +	 * offset inside the memory chunk
> +	 */
> +	if (ilog2(sess_queue_depth - 1) + ilog2(rcv_buf_size - 1) >
> +	    MAX_IMM_PAYL_BITS) {
> +		pr_err("RDMA immediate size (%db) not enough to encode "
> +		       "%d buffers of size %dB. Reduce 'sess_queue_depth' "
> +		       "or 'max_io_size' parameters.\n", MAX_IMM_PAYL_BITS,
> +		       sess_queue_depth, rcv_buf_size);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int __init ibtrs_server_init(void)
> +{
> +	int err;
> +
> +	if (!strlen(cq_affinity_list))
> +		init_cq_affinity();
> +
> +	pr_info("Loading module %s, version: %s "
> +		"(retry_count: %d, cq_affinity_list: %s, "
> +		"max_io_size: %d, sess_queue_depth: %d)\n",
> +		KBUILD_MODNAME, IBTRS_VER_STRING, retry_count,
> +		cq_affinity_list, max_io_size, sess_queue_depth);
> +
> +	err = check_module_params();
> +	if (err) {
> +		pr_err("Failed to load module, invalid module parameters,"
> +		       " err: %d\n", err);
> +		return err;
> +	}
> +	chunk_pool = mempool_create_page_pool(CHUNK_POOL_SIZE,
> +					      get_order(rcv_buf_size));
> +	if (unlikely(!chunk_pool)) {
> +		pr_err("Failed preallocate pool of chunks\n");
> +		return -ENOMEM;
> +	}
> +	ibtrs_wq = alloc_workqueue("ibtrs_server_wq", WQ_MEM_RECLAIM, 0);
> +	if (!ibtrs_wq) {
> +		pr_err("Failed to load module, alloc ibtrs_server_wq failed\n");
> +		goto out_chunk_pool;
> +	}
> +	err = ibtrs_srv_create_sysfs_module_files();
> +	if (err) {
> +		pr_err("Failed to load module, can't create sysfs files,"
> +		       " err: %d\n", err);
> +		goto out_ibtrs_wq;
> +	}
> +
> +	return 0;
> +
> +out_ibtrs_wq:
> +	destroy_workqueue(ibtrs_wq);
> +out_chunk_pool:
> +	mempool_destroy(chunk_pool);
> +
> +	return err;
> +}
> +
> +static void __exit ibtrs_server_exit(void)
> +{
> +	ibtrs_srv_destroy_sysfs_module_files();
> +	destroy_workqueue(ibtrs_wq);
> +	mempool_destroy(chunk_pool);
> +}
> +
> +module_init(ibtrs_server_init);
> +module_exit(ibtrs_server_exit);
>
Roman Pen Feb. 6, 2018, 12:46 p.m. UTC | #2
On Mon, Feb 5, 2018 at 12:29 PM, Sagi Grimberg <sagi@grimberg.me> wrote:
> Hi Roman,
>
> Some comments below.
>
>
> On 02/02/2018 04:08 PM, Roman Pen wrote:
>>
>> This is main functionality of ibtrs-server module, which accepts
>> set of RDMA connections (so called IBTRS session), creates/destroys
>> sysfs entries associated with IBTRS session and notifies upper layer
>> (user of IBTRS API) about RDMA requests or link events.
>>
>> Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
>> Signed-off-by: Danil Kipnis <danil.kipnis@profitbricks.com>
>> Cc: Jack Wang <jinpu.wang@profitbricks.com>
>> ---
>>   drivers/infiniband/ulp/ibtrs/ibtrs-srv.c | 1811
>> ++++++++++++++++++++++++++++++
>>   1 file changed, 1811 insertions(+)
>>
>> diff --git a/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
>> b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
>> new file mode 100644
>> index 000000000000..0d1fc08bd821
>> --- /dev/null
>> +++ b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
>> @@ -0,0 +1,1811 @@
>> +/*
>> + * InfiniBand Transport Layer
>> + *
>> + * Copyright (c) 2014 - 2017 ProfitBricks GmbH. All rights reserved.
>> + * Authors: Fabian Holler <mail@fholler.de>
>> + *          Jack Wang <jinpu.wang@profitbricks.com>
>> + *          Kleber Souza <kleber.souza@profitbricks.com>
>> + *          Danil Kipnis <danil.kipnis@profitbricks.com>
>> + *          Roman Penyaev <roman.penyaev@profitbricks.com>
>> + *          Milind Dumbare <Milind.dumbare@gmail.com>
>> + *
>> + * Copyright (c) 2017 - 2018 ProfitBricks GmbH. All rights reserved.
>> + * Authors: Danil Kipnis <danil.kipnis@profitbricks.com>
>> + *          Roman Penyaev <roman.penyaev@profitbricks.com>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * as published by the Free Software Foundation; either version 2
>> + * of the License, or (at your option) any later version.
>> + *
>> + * 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 for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#undef pr_fmt
>> +#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
>> +
>> +#include <linux/module.h>
>> +#include <linux/mempool.h>
>> +
>> +#include "ibtrs-srv.h"
>> +#include "ibtrs-log.h"
>> +
>> +MODULE_AUTHOR("ibnbd@profitbricks.com");
>> +MODULE_DESCRIPTION("IBTRS Server");
>> +MODULE_VERSION(IBTRS_VER_STRING);
>> +MODULE_LICENSE("GPL");
>> +
>> +#define DEFAULT_MAX_IO_SIZE_KB 128
>> +#define DEFAULT_MAX_IO_SIZE (DEFAULT_MAX_IO_SIZE_KB * 1024)
>> +#define MAX_REQ_SIZE PAGE_SIZE
>> +#define MAX_SG_COUNT ((MAX_REQ_SIZE - sizeof(struct ibtrs_msg_rdma_read))
>> \
>> +                     / sizeof(struct ibtrs_sg_desc))
>> +
>> +static int max_io_size = DEFAULT_MAX_IO_SIZE;
>> +static int rcv_buf_size = DEFAULT_MAX_IO_SIZE + MAX_REQ_SIZE;
>> +
>> +static int max_io_size_set(const char *val, const struct kernel_param
>> *kp)
>> +{
>> +       int err, ival;
>> +
>> +       err = kstrtoint(val, 0, &ival);
>> +       if (err)
>> +               return err;
>> +
>> +       if (ival < 4096 || ival + MAX_REQ_SIZE > (4096 * 1024) ||
>> +           (ival + MAX_REQ_SIZE) % 512 != 0) {
>> +               pr_err("Invalid max io size value %d, has to be"
>> +                      " > %d, < %d\n", ival, 4096, 4194304);
>> +               return -EINVAL;
>> +       }
>> +
>> +       max_io_size = ival;
>> +       rcv_buf_size = max_io_size + MAX_REQ_SIZE;
>> +       pr_info("max io size changed to %d\n", ival);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct kernel_param_ops max_io_size_ops = {
>> +       .set            = max_io_size_set,
>> +       .get            = param_get_int,
>> +};
>> +module_param_cb(max_io_size, &max_io_size_ops, &max_io_size, 0444);
>> +MODULE_PARM_DESC(max_io_size,
>> +                "Max size for each IO request, when change the unit is in
>> byte"
>> +                " (default: " __stringify(DEFAULT_MAX_IO_SIZE_KB) "KB)");
>> +
>> +#define DEFAULT_SESS_QUEUE_DEPTH 512
>> +static int sess_queue_depth = DEFAULT_SESS_QUEUE_DEPTH;
>> +module_param_named(sess_queue_depth, sess_queue_depth, int, 0444);
>> +MODULE_PARM_DESC(sess_queue_depth,
>> +                "Number of buffers for pending I/O requests to allocate"
>> +                " per session. Maximum: "
>> __stringify(MAX_SESS_QUEUE_DEPTH)
>> +                " (default: " __stringify(DEFAULT_SESS_QUEUE_DEPTH) ")");
>> +
>> +/* We guarantee to serve 10 paths at least */
>> +#define CHUNK_POOL_SIZE (DEFAULT_SESS_QUEUE_DEPTH * 10)
>> +static mempool_t *chunk_pool;
>> +
>> +static int retry_count = 7;
>> +
>> +static int retry_count_set(const char *val, const struct kernel_param
>> *kp)
>> +{
>> +       int err, ival;
>> +
>> +       err = kstrtoint(val, 0, &ival);
>> +       if (err)
>> +               return err;
>> +
>> +       if (ival < MIN_RTR_CNT || ival > MAX_RTR_CNT) {
>> +               pr_err("Invalid retry count value %d, has to be"
>> +                      " > %d, < %d\n", ival, MIN_RTR_CNT, MAX_RTR_CNT);
>> +               return -EINVAL;
>> +       }
>> +
>> +       retry_count = ival;
>> +       pr_info("QP retry count changed to %d\n", ival);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct kernel_param_ops retry_count_ops = {
>> +       .set            = retry_count_set,
>> +       .get            = param_get_int,
>> +};
>> +module_param_cb(retry_count, &retry_count_ops, &retry_count, 0644);
>> +
>> +MODULE_PARM_DESC(retry_count, "Number of times to send the message if
>> the"
>> +                " remote side didn't respond with Ack or Nack (default:
>> 3,"
>> +                " min: " __stringify(MIN_RTR_CNT) ", max: "
>> +                __stringify(MAX_RTR_CNT) ")");
>> +
>> +static char cq_affinity_list[256] = "";
>> +static cpumask_t cq_affinity_mask = { CPU_BITS_ALL };
>> +
>> +static void init_cq_affinity(void)
>> +{
>> +       sprintf(cq_affinity_list, "0-%d", nr_cpu_ids - 1);
>> +}
>> +
>> +static int cq_affinity_list_set(const char *val, const struct
>> kernel_param *kp)
>> +{
>> +       int ret = 0, len = strlen(val);
>> +       cpumask_var_t new_value;
>> +
>> +       if (!strlen(cq_affinity_list))
>> +               init_cq_affinity();
>> +
>> +       if (len >= sizeof(cq_affinity_list))
>> +               return -EINVAL;
>> +       if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
>> +               return -ENOMEM;
>> +
>> +       ret = cpulist_parse(val, new_value);
>> +       if (ret) {
>> +               pr_err("Can't set cq_affinity_list \"%s\": %d\n", val,
>> +                      ret);
>> +               goto free_cpumask;
>> +       }
>> +
>> +       strlcpy(cq_affinity_list, val, sizeof(cq_affinity_list));
>> +       *strchrnul(cq_affinity_list, '\n') = '\0';
>> +       cpumask_copy(&cq_affinity_mask, new_value);
>> +
>> +       pr_info("cq_affinity_list changed to %*pbl\n",
>> +               cpumask_pr_args(&cq_affinity_mask));
>> +free_cpumask:
>> +       free_cpumask_var(new_value);
>> +       return ret;
>> +}
>> +
>> +static struct kparam_string cq_affinity_list_kparam_str = {
>> +       .maxlen = sizeof(cq_affinity_list),
>> +       .string = cq_affinity_list
>> +};
>> +
>> +static const struct kernel_param_ops cq_affinity_list_ops = {
>> +       .set    = cq_affinity_list_set,
>> +       .get    = param_get_string,
>> +};
>> +
>> +module_param_cb(cq_affinity_list, &cq_affinity_list_ops,
>> +               &cq_affinity_list_kparam_str, 0644);
>> +MODULE_PARM_DESC(cq_affinity_list, "Sets the list of cpus to use as cq
>> vectors."
>> +                "(default: use all possible CPUs)");
>> +
>
>
> Can you explain why not using configfs?

No reason, will switch.

>> +static void ibtrs_srv_close_work(struct work_struct *work)
>> +{
>> +       struct ibtrs_srv_sess *sess;
>> +       struct ibtrs_srv_ctx *ctx;
>> +       struct ibtrs_srv_con *con;
>> +       int i;
>> +
>> +       sess = container_of(work, typeof(*sess), close_work);
>> +       ctx = sess->srv->ctx;
>> +
>> +       ibtrs_srv_destroy_sess_files(sess);
>> +       ibtrs_srv_stop_hb(sess);
>> +
>> +       for (i = 0; i < sess->s.con_num; i++) {
>> +               con = to_srv_con(sess->s.con[i]);
>> +               if (!con)
>> +                       continue;
>> +
>> +               rdma_disconnect(con->c.cm_id);
>> +               ib_drain_qp(con->c.qp);
>> +       }
>> +       /* Wait for all inflights */
>> +       ibtrs_srv_wait_ops_ids(sess);
>> +
>> +       /* Notify upper layer if we are the last path */
>> +       ibtrs_srv_sess_down(sess);
>> +
>> +       unmap_cont_bufs(sess);
>> +       ibtrs_srv_free_ops_ids(sess);
>> +
>> +       for (i = 0; i < sess->s.con_num; i++) {
>> +               con = to_srv_con(sess->s.con[i]);
>> +               if (!con)
>> +                       continue;
>> +
>> +               ibtrs_cq_qp_destroy(&con->c);
>> +               rdma_destroy_id(con->c.cm_id);
>> +               kfree(con);
>> +       }
>> +       ibtrs_ib_dev_put(sess->s.ib_dev);
>> +
>> +       del_path_from_srv(sess);
>> +       put_srv(sess->srv);
>> +       sess->srv = NULL;
>> +       ibtrs_srv_change_state(sess, IBTRS_SRV_CLOSED);
>> +
>> +       kfree(sess->rdma_addr);
>> +       kfree(sess->s.con);
>> +       kfree(sess);
>> +}
>> +
>> +static int ibtrs_rdma_do_accept(struct ibtrs_srv_sess *sess,
>> +                               struct rdma_cm_id *cm_id)
>> +{
>> +       struct ibtrs_srv *srv = sess->srv;
>> +       struct ibtrs_msg_conn_rsp msg;
>> +       struct rdma_conn_param param;
>> +       int err;
>> +
>> +       memset(&param, 0, sizeof(param));
>> +       param.retry_count = retry_count;
>> +       param.rnr_retry_count = 7;
>> +       param.private_data = &msg;
>> +       param.private_data_len = sizeof(msg);
>> +
>> +       memset(&msg, 0, sizeof(msg));
>> +       msg.magic = cpu_to_le16(IBTRS_MAGIC);
>> +       msg.version = cpu_to_le16(IBTRS_VERSION);
>> +       msg.errno = 0;
>> +       msg.queue_depth = cpu_to_le16(srv->queue_depth);
>> +       msg.rkey = cpu_to_le32(sess->s.ib_dev->rkey);
>
>
> As said, this cannot happen anymore...

We've already planned to change that.  Would be interesting to see
the performance results.

>> +static struct rdma_cm_id *ibtrs_srv_cm_init(struct ibtrs_srv_ctx *ctx,
>> +                                           struct sockaddr *addr,
>> +                                           enum rdma_port_space ps)
>> +{
>> +       struct rdma_cm_id *cm_id;
>> +       int ret;
>> +
>> +       cm_id = rdma_create_id(&init_net, ibtrs_srv_rdma_cm_handler,
>> +                              ctx, ps, IB_QPT_RC);
>> +       if (IS_ERR(cm_id)) {
>> +               ret = PTR_ERR(cm_id);
>> +               pr_err("Creating id for RDMA connection failed, err:
>> %d\n",
>> +                      ret);
>> +               goto err_out;
>> +       }
>> +       ret = rdma_bind_addr(cm_id, addr);
>> +       if (ret) {
>> +               pr_err("Binding RDMA address failed, err: %d\n", ret);
>> +               goto err_cm;
>> +       }
>> +       ret = rdma_listen(cm_id, 64);
>> +       if (ret) {
>> +               pr_err("Listening on RDMA connection failed, err: %d\n",
>> +                      ret);
>> +               goto err_cm;
>> +       }
>> +
>> +       switch (addr->sa_family) {
>> +       case AF_INET:
>> +               pr_debug("listening on port %u\n",
>> +                        ntohs(((struct sockaddr_in *)addr)->sin_port));
>> +               break;
>> +       case AF_INET6:
>> +               pr_debug("listening on port %u\n",
>> +                        ntohs(((struct sockaddr_in6 *)addr)->sin6_port));
>> +               break;
>> +       case AF_IB:
>> +               pr_debug("listening on service id 0x%016llx\n",
>> +                        be64_to_cpu(rdma_get_service_id(cm_id, addr)));
>> +               break;
>> +       default:
>> +               pr_debug("listening on address family %u\n",
>> addr->sa_family);
>> +       }
>
>
> We already have printk that accepts address format...

Nice, thanks.

>> +
>> +       return cm_id;
>> +
>> +err_cm:
>> +       rdma_destroy_id(cm_id);
>> +err_out:
>> +
>> +       return ERR_PTR(ret);
>> +}
>> +
>> +static int ibtrs_srv_rdma_init(struct ibtrs_srv_ctx *ctx, unsigned int
>> port)
>> +{
>> +       struct sockaddr_in6 sin = {
>> +               .sin6_family    = AF_INET6,
>> +               .sin6_addr      = IN6ADDR_ANY_INIT,
>> +               .sin6_port      = htons(port),
>> +       };
>> +       struct sockaddr_ib sib = {
>> +               .sib_family                     = AF_IB,
>> +               .sib_addr.sib_subnet_prefix     = 0ULL,
>> +               .sib_addr.sib_interface_id      = 0ULL,
>> +               .sib_sid        = cpu_to_be64(RDMA_IB_IP_PS_IB | port),
>> +               .sib_sid_mask   = cpu_to_be64(0xffffffffffffffffULL),
>> +               .sib_pkey       = cpu_to_be16(0xffff),
>> +       };
>
>
> ipv4?

sockaddr_in6 accepts ipv4 also.

>> +       struct rdma_cm_id *cm_ip, *cm_ib;
>> +       int ret;
>> +
>> +       /*
>> +        * We accept both IPoIB and IB connections, so we need to keep
>> +        * two cm id's, one for each socket type and port space.
>> +        * If the cm initialization of one of the id's fails, we abort
>> +        * everything.
>> +        */
>> +       cm_ip = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sin,
>> RDMA_PS_TCP);
>> +       if (unlikely(IS_ERR(cm_ip)))
>> +               return PTR_ERR(cm_ip);
>> +
>> +       cm_ib = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sib,
>> RDMA_PS_IB);
>> +       if (unlikely(IS_ERR(cm_ib))) {
>> +               ret = PTR_ERR(cm_ib);
>> +               goto free_cm_ip;
>> +       }
>> +
>> +       ctx->cm_id_ip = cm_ip;
>> +       ctx->cm_id_ib = cm_ib;
>> +
>> +       return 0;
>> +
>> +free_cm_ip:
>> +       rdma_destroy_id(cm_ip);
>> +
>> +       return ret;
>> +}
>> +
>> +static struct ibtrs_srv_ctx *alloc_srv_ctx(rdma_ev_fn *rdma_ev,
>> +                                          link_ev_fn *link_ev)
>> +{
>> +       struct ibtrs_srv_ctx *ctx;
>> +
>> +       ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
>> +       if (!ctx)
>> +               return NULL;
>> +
>> +       ctx->rdma_ev = rdma_ev;
>> +       ctx->link_ev = link_ev;
>> +       mutex_init(&ctx->srv_mutex);
>> +       INIT_LIST_HEAD(&ctx->srv_list);
>> +
>> +       return ctx;
>> +}
>> +
>> +static void free_srv_ctx(struct ibtrs_srv_ctx *ctx)
>> +{
>> +       WARN_ON(!list_empty(&ctx->srv_list));
>> +       kfree(ctx);
>> +}
>> +
>> +struct ibtrs_srv_ctx *ibtrs_srv_open(rdma_ev_fn *rdma_ev, link_ev_fn
>> *link_ev,
>> +                                    unsigned int port)
>> +{
>> +       struct ibtrs_srv_ctx *ctx;
>> +       int err;
>> +
>> +       ctx = alloc_srv_ctx(rdma_ev, link_ev);
>> +       if (unlikely(!ctx))
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +       err = ibtrs_srv_rdma_init(ctx, port);
>> +       if (unlikely(err)) {
>> +               free_srv_ctx(ctx);
>> +               return ERR_PTR(err);
>> +       }
>> +       /* Do not let module be unloaded if server context is alive */
>> +       __module_get(THIS_MODULE);
>> +
>> +       return ctx;
>> +}
>> +EXPORT_SYMBOL(ibtrs_srv_open);
>> +
>> +void ibtrs_srv_queue_close(struct ibtrs_srv_sess *sess)
>> +{
>> +       close_sess(sess);
>> +}
>> +
>> +static void close_sess(struct ibtrs_srv_sess *sess)
>> +{
>> +       enum ibtrs_srv_state old_state;
>> +
>> +       if (ibtrs_srv_change_state_get_old(sess, IBTRS_SRV_CLOSING,
>> +                                          &old_state))
>> +               queue_work(ibtrs_wq, &sess->close_work);
>> +       WARN_ON(sess->state != IBTRS_SRV_CLOSING);
>> +}
>> +
>> +static void close_sessions(struct ibtrs_srv *srv)
>> +{
>> +       struct ibtrs_srv_sess *sess;
>> +
>> +       mutex_lock(&srv->paths_mutex);
>> +       list_for_each_entry(sess, &srv->paths_list, s.entry)
>> +               close_sess(sess);
>> +       mutex_unlock(&srv->paths_mutex);
>> +}
>> +
>> +static void close_ctx(struct ibtrs_srv_ctx *ctx)
>> +{
>> +       struct ibtrs_srv *srv;
>> +
>> +       mutex_lock(&ctx->srv_mutex);
>> +       list_for_each_entry(srv, &ctx->srv_list, ctx_list)
>> +               close_sessions(srv);
>> +       mutex_unlock(&ctx->srv_mutex);
>> +       flush_workqueue(ibtrs_wq);
>> +}
>> +
>> +void ibtrs_srv_close(struct ibtrs_srv_ctx *ctx)
>> +{
>> +       rdma_destroy_id(ctx->cm_id_ip);
>> +       rdma_destroy_id(ctx->cm_id_ib);
>> +       close_ctx(ctx);
>> +       free_srv_ctx(ctx);
>> +       module_put(THIS_MODULE);
>> +}
>> +EXPORT_SYMBOL(ibtrs_srv_close);
>> +
>> +static int check_module_params(void)
>> +{
>> +       if (sess_queue_depth < 1 || sess_queue_depth >
>> MAX_SESS_QUEUE_DEPTH) {
>> +               pr_err("Invalid sess_queue_depth parameter value\n");
>> +               return -EINVAL;
>> +       }
>> +
>> +       /* check if IB immediate data size is enough to hold the mem_id
>> and the
>> +        * offset inside the memory chunk
>> +        */
>> +       if (ilog2(sess_queue_depth - 1) + ilog2(rcv_buf_size - 1) >
>> +           MAX_IMM_PAYL_BITS) {
>> +               pr_err("RDMA immediate size (%db) not enough to encode "
>> +                      "%d buffers of size %dB. Reduce 'sess_queue_depth'
>> "
>> +                      "or 'max_io_size' parameters.\n",
>> MAX_IMM_PAYL_BITS,
>> +                      sess_queue_depth, rcv_buf_size);
>> +               return -EINVAL;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int __init ibtrs_server_init(void)
>> +{
>> +       int err;
>> +
>> +       if (!strlen(cq_affinity_list))
>> +               init_cq_affinity();
>> +
>> +       pr_info("Loading module %s, version: %s "
>> +               "(retry_count: %d, cq_affinity_list: %s, "
>> +               "max_io_size: %d, sess_queue_depth: %d)\n",
>> +               KBUILD_MODNAME, IBTRS_VER_STRING, retry_count,
>> +               cq_affinity_list, max_io_size, sess_queue_depth);
>> +
>> +       err = check_module_params();
>> +       if (err) {
>> +               pr_err("Failed to load module, invalid module parameters,"
>> +                      " err: %d\n", err);
>> +               return err;
>> +       }
>> +       chunk_pool = mempool_create_page_pool(CHUNK_POOL_SIZE,
>> +                                             get_order(rcv_buf_size));
>> +       if (unlikely(!chunk_pool)) {
>> +               pr_err("Failed preallocate pool of chunks\n");
>> +               return -ENOMEM;
>> +       }
>> +       ibtrs_wq = alloc_workqueue("ibtrs_server_wq", WQ_MEM_RECLAIM, 0);
>> +       if (!ibtrs_wq) {
>> +               pr_err("Failed to load module, alloc ibtrs_server_wq
>> failed\n");
>> +               goto out_chunk_pool;
>> +       }
>> +       err = ibtrs_srv_create_sysfs_module_files();
>> +       if (err) {
>> +               pr_err("Failed to load module, can't create sysfs files,"
>> +                      " err: %d\n", err);
>> +               goto out_ibtrs_wq;
>> +       }
>> +
>> +       return 0;
>> +
>> +out_ibtrs_wq:
>> +       destroy_workqueue(ibtrs_wq);
>> +out_chunk_pool:
>> +       mempool_destroy(chunk_pool);
>> +
>> +       return err;
>> +}
>> +
>> +static void __exit ibtrs_server_exit(void)
>> +{
>> +       ibtrs_srv_destroy_sysfs_module_files();
>> +       destroy_workqueue(ibtrs_wq);
>> +       mempool_destroy(chunk_pool);
>> +}
>> +
>> +module_init(ibtrs_server_init);
>> +module_exit(ibtrs_server_exit);
>>
>
diff mbox

Patch

diff --git a/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
new file mode 100644
index 000000000000..0d1fc08bd821
--- /dev/null
+++ b/drivers/infiniband/ulp/ibtrs/ibtrs-srv.c
@@ -0,0 +1,1811 @@ 
+/*
+ * InfiniBand Transport Layer
+ *
+ * Copyright (c) 2014 - 2017 ProfitBricks GmbH. All rights reserved.
+ * Authors: Fabian Holler <mail@fholler.de>
+ *          Jack Wang <jinpu.wang@profitbricks.com>
+ *          Kleber Souza <kleber.souza@profitbricks.com>
+ *          Danil Kipnis <danil.kipnis@profitbricks.com>
+ *          Roman Penyaev <roman.penyaev@profitbricks.com>
+ *          Milind Dumbare <Milind.dumbare@gmail.com>
+ *
+ * Copyright (c) 2017 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Authors: Danil Kipnis <danil.kipnis@profitbricks.com>
+ *          Roman Penyaev <roman.penyaev@profitbricks.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
+
+#include <linux/module.h>
+#include <linux/mempool.h>
+
+#include "ibtrs-srv.h"
+#include "ibtrs-log.h"
+
+MODULE_AUTHOR("ibnbd@profitbricks.com");
+MODULE_DESCRIPTION("IBTRS Server");
+MODULE_VERSION(IBTRS_VER_STRING);
+MODULE_LICENSE("GPL");
+
+#define DEFAULT_MAX_IO_SIZE_KB 128
+#define DEFAULT_MAX_IO_SIZE (DEFAULT_MAX_IO_SIZE_KB * 1024)
+#define MAX_REQ_SIZE PAGE_SIZE
+#define MAX_SG_COUNT ((MAX_REQ_SIZE - sizeof(struct ibtrs_msg_rdma_read)) \
+		      / sizeof(struct ibtrs_sg_desc))
+
+static int max_io_size = DEFAULT_MAX_IO_SIZE;
+static int rcv_buf_size = DEFAULT_MAX_IO_SIZE + MAX_REQ_SIZE;
+
+static int max_io_size_set(const char *val, const struct kernel_param *kp)
+{
+	int err, ival;
+
+	err = kstrtoint(val, 0, &ival);
+	if (err)
+		return err;
+
+	if (ival < 4096 || ival + MAX_REQ_SIZE > (4096 * 1024) ||
+	    (ival + MAX_REQ_SIZE) % 512 != 0) {
+		pr_err("Invalid max io size value %d, has to be"
+		       " > %d, < %d\n", ival, 4096, 4194304);
+		return -EINVAL;
+	}
+
+	max_io_size = ival;
+	rcv_buf_size = max_io_size + MAX_REQ_SIZE;
+	pr_info("max io size changed to %d\n", ival);
+
+	return 0;
+}
+
+static const struct kernel_param_ops max_io_size_ops = {
+	.set		= max_io_size_set,
+	.get		= param_get_int,
+};
+module_param_cb(max_io_size, &max_io_size_ops, &max_io_size, 0444);
+MODULE_PARM_DESC(max_io_size,
+		 "Max size for each IO request, when change the unit is in byte"
+		 " (default: " __stringify(DEFAULT_MAX_IO_SIZE_KB) "KB)");
+
+#define DEFAULT_SESS_QUEUE_DEPTH 512
+static int sess_queue_depth = DEFAULT_SESS_QUEUE_DEPTH;
+module_param_named(sess_queue_depth, sess_queue_depth, int, 0444);
+MODULE_PARM_DESC(sess_queue_depth,
+		 "Number of buffers for pending I/O requests to allocate"
+		 " per session. Maximum: " __stringify(MAX_SESS_QUEUE_DEPTH)
+		 " (default: " __stringify(DEFAULT_SESS_QUEUE_DEPTH) ")");
+
+/* We guarantee to serve 10 paths at least */
+#define CHUNK_POOL_SIZE (DEFAULT_SESS_QUEUE_DEPTH * 10)
+static mempool_t *chunk_pool;
+
+static int retry_count = 7;
+
+static int retry_count_set(const char *val, const struct kernel_param *kp)
+{
+	int err, ival;
+
+	err = kstrtoint(val, 0, &ival);
+	if (err)
+		return err;
+
+	if (ival < MIN_RTR_CNT || ival > MAX_RTR_CNT) {
+		pr_err("Invalid retry count value %d, has to be"
+		       " > %d, < %d\n", ival, MIN_RTR_CNT, MAX_RTR_CNT);
+		return -EINVAL;
+	}
+
+	retry_count = ival;
+	pr_info("QP retry count changed to %d\n", ival);
+
+	return 0;
+}
+
+static const struct kernel_param_ops retry_count_ops = {
+	.set		= retry_count_set,
+	.get		= param_get_int,
+};
+module_param_cb(retry_count, &retry_count_ops, &retry_count, 0644);
+
+MODULE_PARM_DESC(retry_count, "Number of times to send the message if the"
+		 " remote side didn't respond with Ack or Nack (default: 3,"
+		 " min: " __stringify(MIN_RTR_CNT) ", max: "
+		 __stringify(MAX_RTR_CNT) ")");
+
+static char cq_affinity_list[256] = "";
+static cpumask_t cq_affinity_mask = { CPU_BITS_ALL };
+
+static void init_cq_affinity(void)
+{
+	sprintf(cq_affinity_list, "0-%d", nr_cpu_ids - 1);
+}
+
+static int cq_affinity_list_set(const char *val, const struct kernel_param *kp)
+{
+	int ret = 0, len = strlen(val);
+	cpumask_var_t new_value;
+
+	if (!strlen(cq_affinity_list))
+		init_cq_affinity();
+
+	if (len >= sizeof(cq_affinity_list))
+		return -EINVAL;
+	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = cpulist_parse(val, new_value);
+	if (ret) {
+		pr_err("Can't set cq_affinity_list \"%s\": %d\n", val,
+		       ret);
+		goto free_cpumask;
+	}
+
+	strlcpy(cq_affinity_list, val, sizeof(cq_affinity_list));
+	*strchrnul(cq_affinity_list, '\n') = '\0';
+	cpumask_copy(&cq_affinity_mask, new_value);
+
+	pr_info("cq_affinity_list changed to %*pbl\n",
+		cpumask_pr_args(&cq_affinity_mask));
+free_cpumask:
+	free_cpumask_var(new_value);
+	return ret;
+}
+
+static struct kparam_string cq_affinity_list_kparam_str = {
+	.maxlen	= sizeof(cq_affinity_list),
+	.string	= cq_affinity_list
+};
+
+static const struct kernel_param_ops cq_affinity_list_ops = {
+	.set	= cq_affinity_list_set,
+	.get	= param_get_string,
+};
+
+module_param_cb(cq_affinity_list, &cq_affinity_list_ops,
+		&cq_affinity_list_kparam_str, 0644);
+MODULE_PARM_DESC(cq_affinity_list, "Sets the list of cpus to use as cq vectors."
+		 "(default: use all possible CPUs)");
+
+static struct workqueue_struct *ibtrs_wq;
+
+static void close_sess(struct ibtrs_srv_sess *sess);
+
+static inline struct ibtrs_srv_con *to_srv_con(struct ibtrs_con *c)
+{
+	if (unlikely(!c))
+		return NULL;
+
+	return container_of(c, struct ibtrs_srv_con, c);
+}
+
+static inline struct ibtrs_srv_sess *to_srv_sess(struct ibtrs_sess *s)
+{
+	if (unlikely(!s))
+		return NULL;
+
+	return container_of(s, struct ibtrs_srv_sess, s);
+}
+
+static bool __ibtrs_srv_change_state(struct ibtrs_srv_sess *sess,
+				     enum ibtrs_srv_state new_state)
+{
+	enum ibtrs_srv_state old_state;
+	bool changed = false;
+
+	old_state = sess->state;
+	switch (new_state) {
+	case IBTRS_SRV_CONNECTED:
+		switch (old_state) {
+		case IBTRS_SRV_CONNECTING:
+			changed = true;
+			/* FALLTHRU */
+		default:
+			break;
+		}
+		break;
+	case IBTRS_SRV_CLOSING:
+		switch (old_state) {
+		case IBTRS_SRV_CONNECTING:
+		case IBTRS_SRV_CONNECTED:
+			changed = true;
+			/* FALLTHRU */
+		default:
+			break;
+		}
+		break;
+	case IBTRS_SRV_CLOSED:
+		switch (old_state) {
+		case IBTRS_SRV_CLOSING:
+			changed = true;
+			/* FALLTHRU */
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+	if (changed)
+		sess->state = new_state;
+
+	return changed;
+}
+
+static bool ibtrs_srv_change_state_get_old(struct ibtrs_srv_sess *sess,
+					   enum ibtrs_srv_state new_state,
+					   enum ibtrs_srv_state *old_state)
+{
+	bool changed;
+
+	spin_lock_irq(&sess->state_lock);
+	*old_state = sess->state;
+	changed = __ibtrs_srv_change_state(sess, new_state);
+	spin_unlock_irq(&sess->state_lock);
+
+	return changed;
+}
+
+static bool ibtrs_srv_change_state(struct ibtrs_srv_sess *sess,
+				   enum ibtrs_srv_state new_state)
+{
+	enum ibtrs_srv_state old_state;
+
+	return ibtrs_srv_change_state_get_old(sess, new_state, &old_state);
+}
+
+static void free_id(struct ibtrs_srv_op *id)
+{
+	if (!id)
+		return;
+	kfree(id->tx_wr);
+	kfree(id->tx_sg);
+	kfree(id);
+}
+
+static void ibtrs_srv_free_ops_ids(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	int i;
+
+	WARN_ON(atomic_read(&sess->ids_inflight));
+	if (sess->ops_ids) {
+		for (i = 0; i < srv->queue_depth; i++)
+			free_id(sess->ops_ids[i]);
+		kfree(sess->ops_ids);
+		sess->ops_ids = NULL;
+	}
+}
+
+static int ibtrs_srv_alloc_ops_ids(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_op *id;
+	int i;
+
+	sess->ops_ids = kcalloc(srv->queue_depth, sizeof(*sess->ops_ids),
+				GFP_KERNEL);
+	if (unlikely(!sess->ops_ids))
+		goto err;
+
+	for (i = 0; i < srv->queue_depth; ++i) {
+		id = kzalloc(sizeof(*id), GFP_KERNEL);
+		if (unlikely(!id))
+			goto err;
+
+		sess->ops_ids[i] = id;
+		id->tx_wr = kcalloc(MAX_SG_COUNT, sizeof(*id->tx_wr),
+				    GFP_KERNEL);
+		if (unlikely(!id->tx_wr))
+			goto err;
+
+		id->tx_sg = kcalloc(MAX_SG_COUNT, sizeof(*id->tx_sg),
+				    GFP_KERNEL);
+		if (unlikely(!id->tx_sg))
+			goto err;
+	}
+	init_waitqueue_head(&sess->ids_waitq);
+	atomic_set(&sess->ids_inflight, 0);
+
+	return 0;
+
+err:
+	ibtrs_srv_free_ops_ids(sess);
+	return -ENOMEM;
+}
+
+static void ibtrs_srv_get_ops_ids(struct ibtrs_srv_sess *sess)
+{
+	atomic_inc(&sess->ids_inflight);
+}
+
+static void ibtrs_srv_put_ops_ids(struct ibtrs_srv_sess *sess)
+{
+	if (atomic_dec_and_test(&sess->ids_inflight))
+		wake_up(&sess->ids_waitq);
+}
+
+static void ibtrs_srv_wait_ops_ids(struct ibtrs_srv_sess *sess)
+{
+	wait_event(sess->ids_waitq, !atomic_read(&sess->ids_inflight));
+}
+
+static void ibtrs_srv_rdma_done(struct ib_cq *cq, struct ib_wc *wc);
+
+static struct ib_cqe io_comp_cqe = {
+	.done = ibtrs_srv_rdma_done
+};
+
+static int rdma_write_sg(struct ibtrs_srv_op *id)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(id->con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	struct ib_rdma_wr *wr = NULL;
+	struct ib_send_wr *bad_wr;
+	enum ib_send_flags flags;
+	size_t sg_cnt;
+	int err, i, offset;
+
+	sg_cnt = le32_to_cpu(id->msg->sg_cnt);
+	if (unlikely(!sg_cnt))
+		return -EINVAL;
+
+	offset = 0;
+	for (i = 0; i < sg_cnt; i++) {
+		struct ib_sge *list;
+
+		wr		= &id->tx_wr[i];
+		list		= &id->tx_sg[i];
+		list->addr	= id->data_dma_addr + offset;
+		list->length	= le32_to_cpu(id->msg->desc[i].len);
+
+		/* WR will fail with length error
+		 * if this is 0
+		 */
+		if (unlikely(list->length == 0)) {
+			ibtrs_err(sess, "Invalid RDMA-Write sg list length 0\n");
+			return -EINVAL;
+		}
+
+		list->lkey = sess->s.ib_dev->lkey;
+		offset += list->length;
+
+		wr->wr.wr_cqe	= &io_comp_cqe;
+		wr->wr.sg_list	= list;
+		wr->wr.num_sge	= 1;
+		wr->remote_addr	= le64_to_cpu(id->msg->desc[i].addr);
+		wr->rkey	= le32_to_cpu(id->msg->desc[i].key);
+
+		if (i < (sg_cnt - 1)) {
+			wr->wr.next	= &id->tx_wr[i + 1].wr;
+			wr->wr.opcode	= IB_WR_RDMA_WRITE;
+			wr->wr.ex.imm_data	= 0;
+			wr->wr.send_flags	= 0;
+		}
+	}
+	/*
+	 * From time to time we have to post signalled sends,
+	 * or send queue will fill up and only QP reset can help.
+	 */
+	flags = atomic_inc_return(&id->con->wr_cnt) % srv->queue_depth ?
+			0 : IB_SEND_SIGNALED;
+
+	wr->wr.wr_cqe = &io_comp_cqe;
+	wr->wr.opcode = IB_WR_RDMA_WRITE_WITH_IMM;
+	wr->wr.next = NULL;
+	wr->wr.send_flags = flags;
+	wr->wr.ex.imm_data = cpu_to_be32(ibtrs_to_io_rsp_imm(id->msg_id, 0));
+
+	err = ib_post_send(id->con->c.qp, &id->tx_wr[0].wr, &bad_wr);
+	if (unlikely(err))
+		ibtrs_err(sess,
+			  "Posting RDMA-Write-Request to QP failed, err: %d\n",
+			  err);
+
+	return err;
+}
+
+static int send_io_resp_imm(struct ibtrs_srv_con *con, int msg_id, s16 errno)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	enum ib_send_flags flags;
+	u32 imm;
+	int err;
+
+	/*
+	 * From time to time we have to post signalled sends,
+	 * or send queue will fill up and only QP reset can help.
+	 */
+	flags = atomic_inc_return(&con->wr_cnt) % srv->queue_depth ?
+			0 : IB_SEND_SIGNALED;
+	imm = ibtrs_to_io_rsp_imm(msg_id, errno);
+	err = ibtrs_post_rdma_write_imm_empty(&con->c, &io_comp_cqe,
+					      imm, flags);
+	if (unlikely(err))
+		ibtrs_err_rl(sess, "ib_post_send(), err: %d\n", err);
+
+	return err;
+}
+
+/*
+ * ibtrs_srv_resp_rdma() - sends response to the client.
+ *
+ * Context: any
+ */
+void ibtrs_srv_resp_rdma(struct ibtrs_srv_op *id, int status)
+{
+	struct ibtrs_srv_con *con = id->con;
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	int err;
+
+	if (WARN_ON(!id))
+		return;
+
+	if (unlikely(sess->state != IBTRS_SRV_CONNECTED)) {
+		ibtrs_err_rl(sess, "Sending I/O response failed, "
+			     " session is disconnected, sess state %s\n",
+			     ibtrs_srv_state_str(sess->state));
+		goto out;
+	}
+	if (status || id->dir == WRITE || !id->msg->sg_cnt)
+		err = send_io_resp_imm(con, id->msg_id, status);
+	else
+		err = rdma_write_sg(id);
+	if (unlikely(err)) {
+		ibtrs_err_rl(sess, "IO response failed: %d\n", err);
+		close_sess(sess);
+	}
+out:
+	ibtrs_srv_put_ops_ids(sess);
+}
+EXPORT_SYMBOL(ibtrs_srv_resp_rdma);
+
+void ibtrs_srv_set_sess_priv(struct ibtrs_srv *srv, void *priv)
+{
+	srv->priv = priv;
+}
+EXPORT_SYMBOL(ibtrs_srv_set_sess_priv);
+
+static void unmap_cont_bufs(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	int i;
+
+	for (i = 0; i < srv->queue_depth; i++)
+		ib_dma_unmap_page(sess->s.ib_dev->dev, sess->rdma_addr[i],
+				  rcv_buf_size, DMA_BIDIRECTIONAL);
+}
+
+static int map_cont_bufs(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	unsigned int chunk_bits;
+	dma_addr_t addr;
+	int i, err;
+
+	for (i = 0; i < srv->queue_depth; i++) {
+		addr = ib_dma_map_page(sess->s.ib_dev->dev, srv->chunks[i],
+				       0, rcv_buf_size, DMA_BIDIRECTIONAL);
+		if (unlikely(ib_dma_mapping_error(sess->s.ib_dev->dev, addr))) {
+			ibtrs_err(sess, "ib_dma_map_page() failed\n");
+			err = -EIO;
+			goto err_map;
+		}
+		sess->rdma_addr[i] = addr;
+	}
+	chunk_bits = ilog2(srv->queue_depth - 1) + 1;
+	sess->mem_bits = (MAX_IMM_PAYL_BITS - chunk_bits);
+
+	return 0;
+
+err_map:
+	while (i--)
+		ib_dma_unmap_page(sess->s.ib_dev->dev, sess->rdma_addr[i],
+				  rcv_buf_size, DMA_BIDIRECTIONAL);
+
+	return err;
+}
+
+static void ibtrs_srv_hb_err_handler(struct ibtrs_con *c, int err)
+{
+	(void)err;
+	close_sess(to_srv_sess(c->sess));
+}
+
+static void ibtrs_srv_init_hb(struct ibtrs_srv_sess *sess)
+{
+	ibtrs_init_hb(&sess->s, &io_comp_cqe,
+		      IBTRS_HB_INTERVAL_MS,
+		      IBTRS_HB_MISSED_MAX,
+		      ibtrs_srv_hb_err_handler,
+		      ibtrs_wq);
+}
+
+static void ibtrs_srv_start_hb(struct ibtrs_srv_sess *sess)
+{
+	ibtrs_start_hb(&sess->s);
+}
+
+static void ibtrs_srv_stop_hb(struct ibtrs_srv_sess *sess)
+{
+	ibtrs_stop_hb(&sess->s);
+}
+
+static void ibtrs_srv_info_rsp_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct ibtrs_srv_con *con = cq->cq_context;
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_iu *iu;
+
+	iu = container_of(wc->wr_cqe, struct ibtrs_iu, cqe);
+	ibtrs_iu_free(iu, DMA_TO_DEVICE, sess->s.ib_dev->dev);
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		ibtrs_err(sess, "Sess info response send failed: %s\n",
+			  ib_wc_status_msg(wc->status));
+		close_sess(sess);
+		return;
+	}
+	WARN_ON(wc->opcode != IB_WC_SEND);
+	ibtrs_srv_update_wc_stats(&sess->stats);
+}
+
+static void ibtrs_srv_sess_up(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_ctx *ctx = srv->ctx;
+	int up;
+
+	mutex_lock(&srv->paths_ev_mutex);
+	up = ++srv->paths_up;
+	if (up == 1)
+		ctx->link_ev(srv, IBTRS_SRV_LINK_EV_CONNECTED, NULL);
+	mutex_unlock(&srv->paths_ev_mutex);
+
+	/* Mark session as established */
+	sess->established = true;
+}
+
+static void ibtrs_srv_sess_down(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_ctx *ctx = srv->ctx;
+
+	if (!sess->established)
+		return;
+
+	sess->established = false;
+	mutex_lock(&srv->paths_ev_mutex);
+	WARN_ON(!srv->paths_up);
+	if (--srv->paths_up == 0)
+		ctx->link_ev(srv, IBTRS_SRV_LINK_EV_DISCONNECTED, srv->priv);
+	mutex_unlock(&srv->paths_ev_mutex);
+}
+
+static int post_recv_sess(struct ibtrs_srv_sess *sess);
+
+static int process_info_req(struct ibtrs_srv_con *con,
+			    struct ibtrs_msg_info_req *msg)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_msg_info_rsp *rsp;
+	struct ibtrs_iu *tx_iu;
+	size_t tx_sz;
+	int i, err;
+
+	err = post_recv_sess(sess);
+	if (unlikely(err)) {
+		ibtrs_err(sess, "post_recv_sess(), err: %d\n", err);
+		return err;
+	}
+	memcpy(sess->s.sessname, msg->sessname, sizeof(sess->s.sessname));
+
+	tx_sz  = sizeof(struct ibtrs_msg_info_rsp);
+	tx_sz += sizeof(u64) * srv->queue_depth;
+	tx_iu = ibtrs_iu_alloc(0, tx_sz, GFP_KERNEL, sess->s.ib_dev->dev,
+			       DMA_TO_DEVICE, ibtrs_srv_info_rsp_done);
+	if (unlikely(!tx_iu)) {
+		ibtrs_err(sess, "ibtrs_iu_alloc(), err: %d\n", -ENOMEM);
+		return -ENOMEM;
+	}
+
+	rsp = tx_iu->buf;
+	rsp->type = cpu_to_le16(IBTRS_MSG_INFO_RSP);
+	rsp->addr_num = cpu_to_le16(srv->queue_depth);
+	for (i = 0; i < srv->queue_depth; i++)
+		rsp->addr[i] = cpu_to_le64(sess->rdma_addr[i]);
+
+	err = ibtrs_srv_create_sess_files(sess);
+	if (unlikely(err))
+		goto iu_free;
+
+	ibtrs_srv_change_state(sess, IBTRS_SRV_CONNECTED);
+	ibtrs_srv_start_hb(sess);
+
+	/*
+	 * We do not account number of established connections at the current
+	 * moment, we rely on the client, which should send info request when
+	 * all connections are successfully established.  Thus, simply notify
+	 * listener with a proper event if we are the first path.
+	 */
+	ibtrs_srv_sess_up(sess);
+
+	/* Send info response */
+	err = ibtrs_iu_post_send(&con->c, tx_iu, tx_sz);
+	if (unlikely(err)) {
+		ibtrs_err(sess, "ibtrs_iu_post_send(), err: %d\n", err);
+iu_free:
+		ibtrs_iu_free(tx_iu, DMA_TO_DEVICE, sess->s.ib_dev->dev);
+	}
+
+	return err;
+}
+
+static void ibtrs_srv_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct ibtrs_srv_con *con = cq->cq_context;
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_msg_info_req *msg;
+	struct ibtrs_iu *iu;
+	int err;
+
+	WARN_ON(con->c.cid);
+
+	iu = container_of(wc->wr_cqe, struct ibtrs_iu, cqe);
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		ibtrs_err(sess, "Sess info request receive failed: %s\n",
+			  ib_wc_status_msg(wc->status));
+		goto close;
+	}
+	WARN_ON(wc->opcode != IB_WC_RECV);
+
+	if (unlikely(wc->byte_len < sizeof(*msg))) {
+		ibtrs_err(sess, "Sess info request is malformed: size %d\n",
+			  wc->byte_len);
+		goto close;
+	}
+	msg = iu->buf;
+	if (unlikely(le32_to_cpu(msg->type) != IBTRS_MSG_INFO_REQ)) {
+		ibtrs_err(sess, "Sess info request is malformed: type %d\n",
+			  le32_to_cpu(msg->type));
+		goto close;
+	}
+	err = process_info_req(con, msg);
+	if (unlikely(err))
+		goto close;
+
+out:
+	ibtrs_iu_free(iu, DMA_FROM_DEVICE, sess->s.ib_dev->dev);
+	return;
+close:
+	close_sess(sess);
+	goto out;
+}
+
+static int post_recv_info_req(struct ibtrs_srv_con *con)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_iu *rx_iu;
+	int err;
+
+	rx_iu = ibtrs_iu_alloc(0, sizeof(struct ibtrs_msg_info_req),
+			       GFP_KERNEL, sess->s.ib_dev->dev,
+			       DMA_FROM_DEVICE, ibtrs_srv_info_req_done);
+	if (unlikely(!rx_iu)) {
+		ibtrs_err(sess, "ibtrs_iu_alloc(): no memory\n");
+		return -ENOMEM;
+	}
+	/* Prepare for getting info response */
+	err = ibtrs_iu_post_recv(&con->c, rx_iu);
+	if (unlikely(err)) {
+		ibtrs_err(sess, "ibtrs_iu_post_recv(), err: %d\n", err);
+		ibtrs_iu_free(rx_iu, DMA_FROM_DEVICE, sess->s.ib_dev->dev);
+		return err;
+	}
+
+	return 0;
+}
+
+static int post_recv_io(struct ibtrs_srv_con *con)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	int i, err;
+
+	for (i = 0; i < srv->queue_depth; i++) {
+		err = ibtrs_post_recv_empty(&con->c, &io_comp_cqe);
+		if (unlikely(err))
+			return err;
+	}
+
+	return 0;
+}
+
+static int post_recv_sess(struct ibtrs_srv_sess *sess)
+{
+	int err, cid;
+
+	for (cid = 0; cid < sess->s.con_num; cid++) {
+		err = post_recv_io(to_srv_con(sess->s.con[cid]));
+		if (unlikely(err)) {
+			ibtrs_err(sess, "post_recv_io(), err: %d\n", err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void process_read(struct ibtrs_srv_con *con,
+			 struct ibtrs_msg_rdma_read *msg,
+			 u32 buf_id, u32 off)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_ctx *ctx = srv->ctx;
+	struct ibtrs_srv_op *id;
+
+	size_t usr_len, data_len;
+	void *data;
+	int ret;
+
+	if (unlikely(sess->state != IBTRS_SRV_CONNECTED)) {
+		ibtrs_err_rl(sess, "Processing read request failed, "
+			     " session is disconnected, sess state %s\n",
+			     ibtrs_srv_state_str(sess->state));
+		return;
+	}
+	ibtrs_srv_get_ops_ids(sess);
+	ibtrs_srv_update_rdma_stats(&sess->stats, off, READ);
+	id = sess->ops_ids[buf_id];
+	id->con		= con;
+	id->dir		= READ;
+	id->msg_id	= buf_id;
+	id->msg		= msg;
+	usr_len = le16_to_cpu(msg->usr_len);
+	data_len = off - usr_len;
+	data = page_address(srv->chunks[buf_id]);
+	id->data_dma_addr = sess->rdma_addr[buf_id];
+	ret = ctx->rdma_ev(srv, srv->priv, id, READ, data, data_len,
+			   data + data_len, usr_len);
+
+	if (unlikely(ret)) {
+		ibtrs_err_rl(sess, "Processing read request failed, user "
+			     "module cb reported for msg_id %d, err: %d\n",
+			     buf_id, ret);
+		goto send_err_msg;
+	}
+
+	return;
+
+send_err_msg:
+	ret = send_io_resp_imm(con, buf_id, ret);
+	if (ret < 0) {
+		ibtrs_err_rl(sess, "Sending err msg for failed RDMA-Write-Req"
+			     " failed, msg_id %d, err: %d\n", buf_id, ret);
+		close_sess(sess);
+	}
+	ibtrs_srv_put_ops_ids(sess);
+}
+
+static void process_write(struct ibtrs_srv_con *con,
+			  struct ibtrs_msg_rdma_write *req,
+			  u32 buf_id, u32 off)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_ctx *ctx = srv->ctx;
+	struct ibtrs_srv_op *id;
+
+	size_t data_len, usr_len;
+	void *data;
+	int ret;
+
+	if (unlikely(sess->state != IBTRS_SRV_CONNECTED)) {
+		ibtrs_err_rl(sess, "Processing write request failed, "
+			     " session is disconnected, sess state %s\n",
+			     ibtrs_srv_state_str(sess->state));
+		return;
+	}
+	ibtrs_srv_get_ops_ids(sess);
+	ibtrs_srv_update_rdma_stats(&sess->stats, off, WRITE);
+	id = sess->ops_ids[buf_id];
+	id->con    = con;
+	id->dir    = WRITE;
+	id->msg_id = buf_id;
+
+	usr_len = le16_to_cpu(req->usr_len);
+	data_len = off - usr_len;
+	data = page_address(srv->chunks[buf_id]);
+	ret = ctx->rdma_ev(srv, srv->priv, id, WRITE, data, data_len,
+			   data + data_len, usr_len);
+	if (unlikely(ret)) {
+		ibtrs_err_rl(sess, "Processing write request failed, user"
+			     " module callback reports err: %d\n", ret);
+		goto send_err_msg;
+	}
+
+	return;
+
+send_err_msg:
+	ret = send_io_resp_imm(con, buf_id, ret);
+	if (ret < 0) {
+		ibtrs_err_rl(sess, "Processing write request failed, sending"
+			     " I/O response failed, msg_id %d, err: %d\n",
+			     buf_id, ret);
+		close_sess(sess);
+	}
+	ibtrs_srv_put_ops_ids(sess);
+}
+
+static void process_io_req(struct ibtrs_srv_con *con, void *msg,
+			   u32 id, u32 off)
+{
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	unsigned int type;
+
+	type = le16_to_cpu(le16_to_cpu(*(__le16 *)msg));
+
+	switch (type) {
+	case IBTRS_MSG_WRITE:
+		process_write(con, msg, id, off);
+		break;
+	case IBTRS_MSG_READ:
+		process_read(con, msg, id, off);
+		break;
+	default:
+		ibtrs_err(sess, "Processing I/O request failed, "
+			  "unknown message type received: 0x%02x\n", type);
+		goto err;
+	}
+
+	return;
+
+err:
+	close_sess(sess);
+}
+
+static void ibtrs_srv_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct ibtrs_srv_con *con = cq->cq_context;
+	struct ibtrs_srv_sess *sess = to_srv_sess(con->c.sess);
+	struct ibtrs_srv *srv = sess->srv;
+	u32 imm_type, imm_payload;
+	int err;
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		if (wc->status != IB_WC_WR_FLUSH_ERR) {
+			ibtrs_err(sess, "%s (wr_cqe: %p,"
+				  " type: %s, vendor_err: 0x%x, len: %u)\n",
+				  ib_wc_status_msg(wc->status), wc->wr_cqe,
+				  ib_wc_opcode_str(wc->opcode),
+				  wc->vendor_err, wc->byte_len);
+			close_sess(sess);
+		}
+		return;
+	}
+	ibtrs_srv_update_wc_stats(&sess->stats);
+
+	switch (wc->opcode) {
+	case IB_WC_RDMA_WRITE:
+		/*
+		 * post_send() RDMA write completions of IO reqs (read/write)
+		 * and hb
+		 */
+		break;
+	case IB_WC_RECV_RDMA_WITH_IMM:
+		/*
+		 * post_recv() RDMA write completions of IO reqs (read/write)
+		 * and hb
+		 */
+		if (WARN_ON(wc->wr_cqe != &io_comp_cqe))
+			return;
+		err = ibtrs_post_recv_empty(&con->c, &io_comp_cqe);
+		if (unlikely(err)) {
+			ibtrs_err(sess, "ibtrs_post_recv(), err: %d\n", err);
+			close_sess(sess);
+			break;
+		}
+		ibtrs_from_imm(be32_to_cpu(wc->ex.imm_data),
+			       &imm_type, &imm_payload);
+		if (likely(imm_type == IBTRS_IO_REQ_IMM)) {
+			u32 msg_id, off;
+			void *data;
+
+			msg_id = imm_payload >> sess->mem_bits;
+			off = imm_payload & ((1 << sess->mem_bits) - 1);
+			if (unlikely(msg_id > srv->queue_depth ||
+				     off > rcv_buf_size)) {
+				ibtrs_err(sess, "Wrong msg_id %u, off %u\n",
+					  msg_id, off);
+				close_sess(sess);
+				return;
+			}
+			data = page_address(srv->chunks[msg_id]) + off;
+			process_io_req(con, data, msg_id, off);
+		} else if (imm_type == IBTRS_HB_MSG_IMM) {
+			WARN_ON(con->c.cid);
+			ibtrs_send_hb_ack(&sess->s);
+		} else if (imm_type == IBTRS_HB_ACK_IMM) {
+			WARN_ON(con->c.cid);
+			sess->s.hb_missed_cnt = 0;
+		} else {
+			ibtrs_wrn(sess, "Unknown IMM type %u\n", imm_type);
+		}
+		break;
+	default:
+		ibtrs_wrn(sess, "Unexpected WC type: %s\n",
+			  ib_wc_opcode_str(wc->opcode));
+		return;
+	}
+}
+
+int ibtrs_srv_get_sess_name(struct ibtrs_srv *srv, char *sessname, size_t len)
+{
+	struct ibtrs_srv_sess *sess;
+	int err = -ENOTCONN;
+
+	mutex_lock(&srv->paths_mutex);
+	list_for_each_entry(sess, &srv->paths_list, s.entry) {
+		if (sess->state != IBTRS_SRV_CONNECTED)
+			continue;
+		memcpy(sessname, sess->s.sessname,
+		       min_t(size_t, sizeof(sess->s.sessname), len));
+		err = 0;
+		break;
+	}
+	mutex_unlock(&srv->paths_mutex);
+
+	return err;
+}
+EXPORT_SYMBOL(ibtrs_srv_get_sess_name);
+
+int ibtrs_srv_get_queue_depth(struct ibtrs_srv *srv)
+{
+	return srv->queue_depth;
+}
+EXPORT_SYMBOL(ibtrs_srv_get_queue_depth);
+
+static int find_next_bit_ring(int cur)
+{
+	int v = cpumask_next(cur, &cq_affinity_mask);
+
+	if (v >= nr_cpu_ids)
+		v = cpumask_first(&cq_affinity_mask);
+	return v;
+}
+
+static int ibtrs_srv_get_next_cq_vector(struct ibtrs_srv_sess *sess)
+{
+	sess->cur_cq_vector = find_next_bit_ring(sess->cur_cq_vector);
+
+	return sess->cur_cq_vector;
+}
+
+static struct ibtrs_srv *__alloc_srv(struct ibtrs_srv_ctx *ctx,
+				     const uuid_t *paths_uuid)
+{
+	struct ibtrs_srv *srv;
+	int i;
+
+	srv = kzalloc(sizeof(*srv), GFP_KERNEL);
+	if  (unlikely(!srv))
+		return NULL;
+
+	refcount_set(&srv->refcount, 1);
+	INIT_LIST_HEAD(&srv->paths_list);
+	mutex_init(&srv->paths_mutex);
+	mutex_init(&srv->paths_ev_mutex);
+	uuid_copy(&srv->paths_uuid, paths_uuid);
+	srv->queue_depth = sess_queue_depth;
+	srv->ctx = ctx;
+
+	srv->chunks = kcalloc(srv->queue_depth, sizeof(*srv->chunks),
+			      GFP_KERNEL);
+	if (unlikely(!srv->chunks))
+		goto err_free_srv;
+
+	for (i = 0; i < srv->queue_depth; i++) {
+		srv->chunks[i] = mempool_alloc(chunk_pool, GFP_KERNEL);
+		if (unlikely(!srv->chunks[i])) {
+			pr_err("mempool_alloc() failed\n");
+			goto err_free_chunks;
+		}
+	}
+	list_add(&srv->ctx_list, &ctx->srv_list);
+
+	return srv;
+
+err_free_chunks:
+	while (i--)
+		mempool_free(srv->chunks[i], chunk_pool);
+	kfree(srv->chunks);
+
+err_free_srv:
+	kfree(srv);
+
+	return NULL;
+}
+
+static void free_srv(struct ibtrs_srv *srv)
+{
+	int i;
+
+	WARN_ON(refcount_read(&srv->refcount));
+	for (i = 0; i < srv->queue_depth; i++)
+		mempool_free(srv->chunks[i], chunk_pool);
+	kfree(srv->chunks);
+	kfree(srv);
+}
+
+static inline struct ibtrs_srv *__find_srv_and_get(struct ibtrs_srv_ctx *ctx,
+						   const uuid_t *paths_uuid)
+{
+	struct ibtrs_srv *srv;
+
+	list_for_each_entry(srv, &ctx->srv_list, ctx_list) {
+		if (uuid_equal(&srv->paths_uuid, paths_uuid) &&
+		    refcount_inc_not_zero(&srv->refcount))
+			return srv;
+	}
+
+	return NULL;
+}
+
+static struct ibtrs_srv *get_or_create_srv(struct ibtrs_srv_ctx *ctx,
+					   const uuid_t *paths_uuid)
+{
+	struct ibtrs_srv *srv;
+
+	mutex_lock(&ctx->srv_mutex);
+	srv = __find_srv_and_get(ctx, paths_uuid);
+	if (!srv)
+		srv = __alloc_srv(ctx, paths_uuid);
+	mutex_unlock(&ctx->srv_mutex);
+
+	return srv;
+}
+
+static void put_srv(struct ibtrs_srv *srv)
+{
+	if (refcount_dec_and_test(&srv->refcount)) {
+		struct ibtrs_srv_ctx *ctx = srv->ctx;
+
+		WARN_ON(srv->kobj.state_in_sysfs);
+		WARN_ON(srv->kobj_paths.state_in_sysfs);
+
+		mutex_lock(&ctx->srv_mutex);
+		list_del(&srv->ctx_list);
+		mutex_unlock(&ctx->srv_mutex);
+		free_srv(srv);
+	}
+}
+
+static void __add_path_to_srv(struct ibtrs_srv *srv,
+			      struct ibtrs_srv_sess *sess)
+{
+	list_add_tail(&sess->s.entry, &srv->paths_list);
+	srv->paths_num++;
+	WARN_ON(srv->paths_num >= MAX_PATHS_NUM);
+}
+
+static void del_path_from_srv(struct ibtrs_srv_sess *sess)
+{
+	struct ibtrs_srv *srv = sess->srv;
+
+	if (WARN_ON(!srv))
+		return;
+
+	mutex_lock(&srv->paths_mutex);
+	list_del(&sess->s.entry);
+	WARN_ON(!srv->paths_num);
+	srv->paths_num--;
+	mutex_unlock(&srv->paths_mutex);
+}
+
+static void ibtrs_srv_close_work(struct work_struct *work)
+{
+	struct ibtrs_srv_sess *sess;
+	struct ibtrs_srv_ctx *ctx;
+	struct ibtrs_srv_con *con;
+	int i;
+
+	sess = container_of(work, typeof(*sess), close_work);
+	ctx = sess->srv->ctx;
+
+	ibtrs_srv_destroy_sess_files(sess);
+	ibtrs_srv_stop_hb(sess);
+
+	for (i = 0; i < sess->s.con_num; i++) {
+		con = to_srv_con(sess->s.con[i]);
+		if (!con)
+			continue;
+
+		rdma_disconnect(con->c.cm_id);
+		ib_drain_qp(con->c.qp);
+	}
+	/* Wait for all inflights */
+	ibtrs_srv_wait_ops_ids(sess);
+
+	/* Notify upper layer if we are the last path */
+	ibtrs_srv_sess_down(sess);
+
+	unmap_cont_bufs(sess);
+	ibtrs_srv_free_ops_ids(sess);
+
+	for (i = 0; i < sess->s.con_num; i++) {
+		con = to_srv_con(sess->s.con[i]);
+		if (!con)
+			continue;
+
+		ibtrs_cq_qp_destroy(&con->c);
+		rdma_destroy_id(con->c.cm_id);
+		kfree(con);
+	}
+	ibtrs_ib_dev_put(sess->s.ib_dev);
+
+	del_path_from_srv(sess);
+	put_srv(sess->srv);
+	sess->srv = NULL;
+	ibtrs_srv_change_state(sess, IBTRS_SRV_CLOSED);
+
+	kfree(sess->rdma_addr);
+	kfree(sess->s.con);
+	kfree(sess);
+}
+
+static int ibtrs_rdma_do_accept(struct ibtrs_srv_sess *sess,
+				struct rdma_cm_id *cm_id)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_msg_conn_rsp msg;
+	struct rdma_conn_param param;
+	int err;
+
+	memset(&param, 0, sizeof(param));
+	param.retry_count = retry_count;
+	param.rnr_retry_count = 7;
+	param.private_data = &msg;
+	param.private_data_len = sizeof(msg);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.magic = cpu_to_le16(IBTRS_MAGIC);
+	msg.version = cpu_to_le16(IBTRS_VERSION);
+	msg.errno = 0;
+	msg.queue_depth = cpu_to_le16(srv->queue_depth);
+	msg.rkey = cpu_to_le32(sess->s.ib_dev->rkey);
+	msg.max_io_size = cpu_to_le32(max_io_size);
+	msg.max_req_size = cpu_to_le32(MAX_REQ_SIZE);
+	uuid_copy(&msg.uuid, &sess->s.uuid);
+
+	err = rdma_accept(cm_id, &param);
+	if (err)
+		pr_err("rdma_accept(), err: %d\n", err);
+
+	return err;
+}
+
+static int ibtrs_rdma_do_reject(struct rdma_cm_id *cm_id, int errno)
+{
+	struct ibtrs_msg_conn_rsp msg;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.magic = cpu_to_le16(IBTRS_MAGIC);
+	msg.version = cpu_to_le16(IBTRS_VERSION);
+	msg.errno = cpu_to_le16(errno);
+
+	err = rdma_reject(cm_id, &msg, sizeof(msg));
+	if (err)
+		pr_err("rdma_reject(), err: %d\n", err);
+
+	/* Bounce errno back */
+	return errno;
+}
+
+static struct ibtrs_srv_sess *
+__find_sess(struct ibtrs_srv *srv, const uuid_t *sess_uuid)
+{
+	struct ibtrs_srv_sess *sess;
+
+	list_for_each_entry(sess, &srv->paths_list, s.entry) {
+		if (uuid_equal(&sess->s.uuid, sess_uuid))
+			return sess;
+	}
+
+	return NULL;
+}
+
+static int create_con(struct ibtrs_srv_sess *sess,
+		      struct rdma_cm_id *cm_id,
+		      unsigned int cid)
+{
+	struct ibtrs_srv *srv = sess->srv;
+	struct ibtrs_srv_con *con;
+
+	u16 cq_size, wr_queue_size;
+	int err, cq_vector;
+
+	con = kzalloc(sizeof(*con), GFP_KERNEL);
+	if (unlikely(!con)) {
+		ibtrs_err(sess, "kzalloc() failed\n");
+		err = -ENOMEM;
+		goto err;
+	}
+
+	con->c.cm_id = cm_id;
+	con->c.sess = &sess->s;
+	con->c.cid = cid;
+	atomic_set(&con->wr_cnt, 0);
+
+	if (con->c.cid == 0) {
+		cq_size       = SERVICE_CON_QUEUE_DEPTH;
+		/* + 2 for drain and heartbeat */
+		wr_queue_size = SERVICE_CON_QUEUE_DEPTH + 2;
+	} else {
+		cq_size       = srv->queue_depth;
+		wr_queue_size = sess->s.ib_dev->attrs.max_qp_wr;
+	}
+
+	cq_vector = ibtrs_srv_get_next_cq_vector(sess);
+
+	/* TODO: SOFTIRQ can be faster, but be careful with softirq context */
+	err = ibtrs_cq_qp_create(&sess->s, &con->c, 1, cq_vector, cq_size,
+				 wr_queue_size, IB_POLL_WORKQUEUE);
+	if (unlikely(err)) {
+		ibtrs_err(sess, "ibtrs_cq_qp_create(), err: %d\n", err);
+		goto free_con;
+	}
+	if (con->c.cid == 0) {
+		err = post_recv_info_req(con);
+		if (unlikely(err))
+			goto free_cqqp;
+	}
+	WARN_ON(sess->s.con[cid]);
+	sess->s.con[cid] = &con->c;
+
+	/*
+	 * Change context from server to current connection.  The other
+	 * way is to use cm_id->qp->qp_context, which does not work on OFED.
+	 */
+	cm_id->context = &con->c;
+
+	return 0;
+
+free_cqqp:
+	ibtrs_cq_qp_destroy(&con->c);
+free_con:
+	kfree(con);
+
+err:
+	return err;
+}
+
+static struct ibtrs_srv_sess *__alloc_sess(struct ibtrs_srv *srv,
+					   struct rdma_cm_id *cm_id,
+					   unsigned int con_num,
+					   unsigned int recon_cnt,
+					   const uuid_t *uuid)
+{
+	struct ibtrs_srv_sess *sess;
+	int err = -ENOMEM;
+
+	if (unlikely(srv->paths_num >= MAX_PATHS_NUM)) {
+		err = -ECONNRESET;
+		goto err;
+	}
+	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
+	if (unlikely(!sess))
+		goto err;
+
+	sess->rdma_addr = kcalloc(srv->queue_depth, sizeof(*sess->rdma_addr),
+				  GFP_KERNEL);
+	if (unlikely(!sess->rdma_addr))
+		goto err_free_sess;
+
+	sess->s.con = kcalloc(con_num, sizeof(*sess->s.con), GFP_KERNEL);
+	if (unlikely(!sess->s.con))
+		goto err_free_rdma_addr;
+
+	sess->state = IBTRS_SRV_CONNECTING;
+	sess->srv = srv;
+	sess->cur_cq_vector = -1;
+	sess->s.dst_addr = cm_id->route.addr.dst_addr;
+	sess->s.con_num = con_num;
+	sess->s.recon_cnt = recon_cnt;
+	uuid_copy(&sess->s.uuid, uuid);
+	spin_lock_init(&sess->state_lock);
+	INIT_WORK(&sess->close_work, ibtrs_srv_close_work);
+	ibtrs_srv_init_hb(sess);
+
+	sess->s.ib_dev = ibtrs_ib_dev_find_get(cm_id);
+	if (unlikely(!sess->s.ib_dev)) {
+		err = -ENOMEM;
+		ibtrs_wrn(sess, "Failed to alloc ibtrs_device\n");
+		goto err_free_con;
+	}
+	err = map_cont_bufs(sess);
+	if (unlikely(err))
+		goto err_put_dev;
+
+	err = ibtrs_srv_alloc_ops_ids(sess);
+	if (unlikely(err))
+		goto err_unmap_bufs;
+
+	__add_path_to_srv(srv, sess);
+
+	return sess;
+
+err_unmap_bufs:
+	unmap_cont_bufs(sess);
+err_put_dev:
+	ibtrs_ib_dev_put(sess->s.ib_dev);
+err_free_con:
+	kfree(sess->s.con);
+err_free_rdma_addr:
+	kfree(sess->rdma_addr);
+err_free_sess:
+	kfree(sess);
+
+err:
+	return ERR_PTR(err);
+}
+
+static int ibtrs_rdma_connect(struct rdma_cm_id *cm_id,
+			      const struct ibtrs_msg_conn_req *msg,
+			      size_t len)
+{
+	struct ibtrs_srv_ctx *ctx = cm_id->context;
+	struct ibtrs_srv_sess *sess;
+	struct ibtrs_srv *srv;
+
+	u16 version, con_num, cid;
+	u16 recon_cnt;
+	int err;
+
+	if (unlikely(len < sizeof(*msg))) {
+		pr_err("Invalid IBTRS connection request");
+		goto reject_w_econnreset;
+	}
+	if (unlikely(le16_to_cpu(msg->magic) != IBTRS_MAGIC)) {
+		pr_err("Invalid IBTRS magic");
+		goto reject_w_econnreset;
+	}
+	version = le16_to_cpu(msg->version);
+	if (unlikely(version >> 8 != IBTRS_VER_MAJOR)) {
+		pr_err("Unsupported major IBTRS version: %d", version);
+		goto reject_w_econnreset;
+	}
+	con_num = le16_to_cpu(msg->cid_num);
+	if (unlikely(con_num > 4096)) {
+		/* Sanity check */
+		pr_err("Too many connections requested: %d\n", con_num);
+		goto reject_w_econnreset;
+	}
+	cid = le16_to_cpu(msg->cid);
+	if (unlikely(cid >= con_num)) {
+		/* Sanity check */
+		pr_err("Incorrect cid: %d >= %d\n", cid, con_num);
+		goto reject_w_econnreset;
+	}
+	recon_cnt = le16_to_cpu(msg->recon_cnt);
+	srv = get_or_create_srv(ctx, &msg->paths_uuid);
+	if (unlikely(!srv)) {
+		err = -ENOMEM;
+		goto reject_w_err;
+	}
+	mutex_lock(&srv->paths_mutex);
+	sess = __find_sess(srv, &msg->sess_uuid);
+	if (sess) {
+		/* Session already holds a reference */
+		put_srv(srv);
+
+		if (unlikely(sess->s.recon_cnt != recon_cnt)) {
+			ibtrs_err(sess, "Reconnect detected %d != %d, but "
+				  "previous session is still alive, reconnect "
+				  "later\n", sess->s.recon_cnt, recon_cnt);
+			mutex_unlock(&srv->paths_mutex);
+			goto reject_w_ebusy;
+		}
+		if (unlikely(sess->state != IBTRS_SRV_CONNECTING)) {
+			ibtrs_err(sess, "Session in wrong state: %s\n",
+				  ibtrs_srv_state_str(sess->state));
+			mutex_unlock(&srv->paths_mutex);
+			goto reject_w_econnreset;
+		}
+		/*
+		 * Sanity checks
+		 */
+		if (unlikely(con_num != sess->s.con_num ||
+			     cid >= sess->s.con_num)) {
+			ibtrs_err(sess, "Incorrect request: %d, %d\n",
+				  cid, con_num);
+			mutex_unlock(&srv->paths_mutex);
+			goto reject_w_econnreset;
+		}
+		if (unlikely(sess->s.con[cid])) {
+			ibtrs_err(sess, "Connection already exists: %d\n",
+				  cid);
+			mutex_unlock(&srv->paths_mutex);
+			goto reject_w_econnreset;
+		}
+	} else {
+		sess = __alloc_sess(srv, cm_id, con_num, recon_cnt,
+				    &msg->sess_uuid);
+		if (unlikely(IS_ERR(sess))) {
+			mutex_unlock(&srv->paths_mutex);
+			put_srv(srv);
+			err = PTR_ERR(sess);
+			goto reject_w_err;
+		}
+	}
+	err = create_con(sess, cm_id, cid);
+	if (unlikely(err)) {
+		(void)ibtrs_rdma_do_reject(cm_id, err);
+		/*
+		 * Since session has other connections we follow normal way
+		 * through workqueue, but still return an error to tell cma.c
+		 * to call rdma_destroy_id() for current connection.
+		 */
+		goto close_and_return_err;
+	}
+	err = ibtrs_rdma_do_accept(sess, cm_id);
+	if (unlikely(err)) {
+		(void)ibtrs_rdma_do_reject(cm_id, err);
+		/*
+		 * Since current connection was successfully added to the
+		 * session we follow normal way through workqueue to close the
+		 * session, thus return 0 to tell cma.c we call
+		 * rdma_destroy_id() ourselves.
+		 */
+		err = 0;
+		goto close_and_return_err;
+	}
+	mutex_unlock(&srv->paths_mutex);
+
+	return 0;
+
+reject_w_err:
+	return ibtrs_rdma_do_reject(cm_id, err);
+
+reject_w_econnreset:
+	return ibtrs_rdma_do_reject(cm_id, -ECONNRESET);
+
+reject_w_ebusy:
+	return ibtrs_rdma_do_reject(cm_id, -EBUSY);
+
+close_and_return_err:
+	close_sess(sess);
+	mutex_unlock(&srv->paths_mutex);
+
+	return err;
+}
+
+static int ibtrs_srv_rdma_cm_handler(struct rdma_cm_id *cm_id,
+				     struct rdma_cm_event *ev)
+{
+	struct ibtrs_srv_sess *sess = NULL;
+
+	if (ev->event != RDMA_CM_EVENT_CONNECT_REQUEST) {
+		struct ibtrs_con *c = cm_id->context;
+
+		sess = to_srv_sess(c->sess);
+	}
+
+	switch (ev->event) {
+	case RDMA_CM_EVENT_CONNECT_REQUEST:
+		/*
+		 * In case of error cma.c will destroy cm_id,
+		 * see cma_process_remove()
+		 */
+		return ibtrs_rdma_connect(cm_id, ev->param.conn.private_data,
+					  ev->param.conn.private_data_len);
+	case RDMA_CM_EVENT_ESTABLISHED:
+		/* Nothing here */
+		break;
+	case RDMA_CM_EVENT_REJECTED:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	case RDMA_CM_EVENT_UNREACHABLE:
+		ibtrs_err(sess, "CM error (CM event: %s, err: %d)\n",
+			  rdma_event_msg(ev->event), ev->status);
+		close_sess(sess);
+		break;
+	case RDMA_CM_EVENT_DISCONNECTED:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+		close_sess(sess);
+		break;
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+		close_sess(sess);
+		break;
+	default:
+		pr_err("Ignoring unexpected CM event %s, err %d\n",
+		       rdma_event_msg(ev->event), ev->status);
+		break;
+	}
+
+	return 0;
+}
+
+static struct rdma_cm_id *ibtrs_srv_cm_init(struct ibtrs_srv_ctx *ctx,
+					    struct sockaddr *addr,
+					    enum rdma_port_space ps)
+{
+	struct rdma_cm_id *cm_id;
+	int ret;
+
+	cm_id = rdma_create_id(&init_net, ibtrs_srv_rdma_cm_handler,
+			       ctx, ps, IB_QPT_RC);
+	if (IS_ERR(cm_id)) {
+		ret = PTR_ERR(cm_id);
+		pr_err("Creating id for RDMA connection failed, err: %d\n",
+		       ret);
+		goto err_out;
+	}
+	ret = rdma_bind_addr(cm_id, addr);
+	if (ret) {
+		pr_err("Binding RDMA address failed, err: %d\n", ret);
+		goto err_cm;
+	}
+	ret = rdma_listen(cm_id, 64);
+	if (ret) {
+		pr_err("Listening on RDMA connection failed, err: %d\n",
+		       ret);
+		goto err_cm;
+	}
+
+	switch (addr->sa_family) {
+	case AF_INET:
+		pr_debug("listening on port %u\n",
+			 ntohs(((struct sockaddr_in *)addr)->sin_port));
+		break;
+	case AF_INET6:
+		pr_debug("listening on port %u\n",
+			 ntohs(((struct sockaddr_in6 *)addr)->sin6_port));
+		break;
+	case AF_IB:
+		pr_debug("listening on service id 0x%016llx\n",
+			 be64_to_cpu(rdma_get_service_id(cm_id, addr)));
+		break;
+	default:
+		pr_debug("listening on address family %u\n", addr->sa_family);
+	}
+
+	return cm_id;
+
+err_cm:
+	rdma_destroy_id(cm_id);
+err_out:
+
+	return ERR_PTR(ret);
+}
+
+static int ibtrs_srv_rdma_init(struct ibtrs_srv_ctx *ctx, unsigned int port)
+{
+	struct sockaddr_in6 sin = {
+		.sin6_family	= AF_INET6,
+		.sin6_addr	= IN6ADDR_ANY_INIT,
+		.sin6_port	= htons(port),
+	};
+	struct sockaddr_ib sib = {
+		.sib_family			= AF_IB,
+		.sib_addr.sib_subnet_prefix	= 0ULL,
+		.sib_addr.sib_interface_id	= 0ULL,
+		.sib_sid	= cpu_to_be64(RDMA_IB_IP_PS_IB | port),
+		.sib_sid_mask	= cpu_to_be64(0xffffffffffffffffULL),
+		.sib_pkey	= cpu_to_be16(0xffff),
+	};
+	struct rdma_cm_id *cm_ip, *cm_ib;
+	int ret;
+
+	/*
+	 * We accept both IPoIB and IB connections, so we need to keep
+	 * two cm id's, one for each socket type and port space.
+	 * If the cm initialization of one of the id's fails, we abort
+	 * everything.
+	 */
+	cm_ip = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sin, RDMA_PS_TCP);
+	if (unlikely(IS_ERR(cm_ip)))
+		return PTR_ERR(cm_ip);
+
+	cm_ib = ibtrs_srv_cm_init(ctx, (struct sockaddr *)&sib, RDMA_PS_IB);
+	if (unlikely(IS_ERR(cm_ib))) {
+		ret = PTR_ERR(cm_ib);
+		goto free_cm_ip;
+	}
+
+	ctx->cm_id_ip = cm_ip;
+	ctx->cm_id_ib = cm_ib;
+
+	return 0;
+
+free_cm_ip:
+	rdma_destroy_id(cm_ip);
+
+	return ret;
+}
+
+static struct ibtrs_srv_ctx *alloc_srv_ctx(rdma_ev_fn *rdma_ev,
+					   link_ev_fn *link_ev)
+{
+	struct ibtrs_srv_ctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	ctx->rdma_ev = rdma_ev;
+	ctx->link_ev = link_ev;
+	mutex_init(&ctx->srv_mutex);
+	INIT_LIST_HEAD(&ctx->srv_list);
+
+	return ctx;
+}
+
+static void free_srv_ctx(struct ibtrs_srv_ctx *ctx)
+{
+	WARN_ON(!list_empty(&ctx->srv_list));
+	kfree(ctx);
+}
+
+struct ibtrs_srv_ctx *ibtrs_srv_open(rdma_ev_fn *rdma_ev, link_ev_fn *link_ev,
+				     unsigned int port)
+{
+	struct ibtrs_srv_ctx *ctx;
+	int err;
+
+	ctx = alloc_srv_ctx(rdma_ev, link_ev);
+	if (unlikely(!ctx))
+		return ERR_PTR(-ENOMEM);
+
+	err = ibtrs_srv_rdma_init(ctx, port);
+	if (unlikely(err)) {
+		free_srv_ctx(ctx);
+		return ERR_PTR(err);
+	}
+	/* Do not let module be unloaded if server context is alive */
+	__module_get(THIS_MODULE);
+
+	return ctx;
+}
+EXPORT_SYMBOL(ibtrs_srv_open);
+
+void ibtrs_srv_queue_close(struct ibtrs_srv_sess *sess)
+{
+	close_sess(sess);
+}
+
+static void close_sess(struct ibtrs_srv_sess *sess)
+{
+	enum ibtrs_srv_state old_state;
+
+	if (ibtrs_srv_change_state_get_old(sess, IBTRS_SRV_CLOSING,
+					   &old_state))
+		queue_work(ibtrs_wq, &sess->close_work);
+	WARN_ON(sess->state != IBTRS_SRV_CLOSING);
+}
+
+static void close_sessions(struct ibtrs_srv *srv)
+{
+	struct ibtrs_srv_sess *sess;
+
+	mutex_lock(&srv->paths_mutex);
+	list_for_each_entry(sess, &srv->paths_list, s.entry)
+		close_sess(sess);
+	mutex_unlock(&srv->paths_mutex);
+}
+
+static void close_ctx(struct ibtrs_srv_ctx *ctx)
+{
+	struct ibtrs_srv *srv;
+
+	mutex_lock(&ctx->srv_mutex);
+	list_for_each_entry(srv, &ctx->srv_list, ctx_list)
+		close_sessions(srv);
+	mutex_unlock(&ctx->srv_mutex);
+	flush_workqueue(ibtrs_wq);
+}
+
+void ibtrs_srv_close(struct ibtrs_srv_ctx *ctx)
+{
+	rdma_destroy_id(ctx->cm_id_ip);
+	rdma_destroy_id(ctx->cm_id_ib);
+	close_ctx(ctx);
+	free_srv_ctx(ctx);
+	module_put(THIS_MODULE);
+}
+EXPORT_SYMBOL(ibtrs_srv_close);
+
+static int check_module_params(void)
+{
+	if (sess_queue_depth < 1 || sess_queue_depth > MAX_SESS_QUEUE_DEPTH) {
+		pr_err("Invalid sess_queue_depth parameter value\n");
+		return -EINVAL;
+	}
+
+	/* check if IB immediate data size is enough to hold the mem_id and the
+	 * offset inside the memory chunk
+	 */
+	if (ilog2(sess_queue_depth - 1) + ilog2(rcv_buf_size - 1) >
+	    MAX_IMM_PAYL_BITS) {
+		pr_err("RDMA immediate size (%db) not enough to encode "
+		       "%d buffers of size %dB. Reduce 'sess_queue_depth' "
+		       "or 'max_io_size' parameters.\n", MAX_IMM_PAYL_BITS,
+		       sess_queue_depth, rcv_buf_size);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __init ibtrs_server_init(void)
+{
+	int err;
+
+	if (!strlen(cq_affinity_list))
+		init_cq_affinity();
+
+	pr_info("Loading module %s, version: %s "
+		"(retry_count: %d, cq_affinity_list: %s, "
+		"max_io_size: %d, sess_queue_depth: %d)\n",
+		KBUILD_MODNAME, IBTRS_VER_STRING, retry_count,
+		cq_affinity_list, max_io_size, sess_queue_depth);
+
+	err = check_module_params();
+	if (err) {
+		pr_err("Failed to load module, invalid module parameters,"
+		       " err: %d\n", err);
+		return err;
+	}
+	chunk_pool = mempool_create_page_pool(CHUNK_POOL_SIZE,
+					      get_order(rcv_buf_size));
+	if (unlikely(!chunk_pool)) {
+		pr_err("Failed preallocate pool of chunks\n");
+		return -ENOMEM;
+	}
+	ibtrs_wq = alloc_workqueue("ibtrs_server_wq", WQ_MEM_RECLAIM, 0);
+	if (!ibtrs_wq) {
+		pr_err("Failed to load module, alloc ibtrs_server_wq failed\n");
+		goto out_chunk_pool;
+	}
+	err = ibtrs_srv_create_sysfs_module_files();
+	if (err) {
+		pr_err("Failed to load module, can't create sysfs files,"
+		       " err: %d\n", err);
+		goto out_ibtrs_wq;
+	}
+
+	return 0;
+
+out_ibtrs_wq:
+	destroy_workqueue(ibtrs_wq);
+out_chunk_pool:
+	mempool_destroy(chunk_pool);
+
+	return err;
+}
+
+static void __exit ibtrs_server_exit(void)
+{
+	ibtrs_srv_destroy_sysfs_module_files();
+	destroy_workqueue(ibtrs_wq);
+	mempool_destroy(chunk_pool);
+}
+
+module_init(ibtrs_server_init);
+module_exit(ibtrs_server_exit);