IB/iser: iSER RDMA CM (CMA) and IB verbs interaction

/*

 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.

 * Copyright (c) 2005, 2006 Cisco Systems.  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.

 *

 * $Id: iser_verbs.c 7051 2006-05-10 12:29:11Z ogerlitz $

 */

#include <asm/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/smp_lock.h>

#include <linux/delay.h>

#include <linux/version.h>

#include "iscsi_iser.h"

#define ISCSI_ISER_MAX_CONN	8

#define ISER_MAX_CQ_LEN		((ISER_QP_MAX_RECV_DTOS + \

				ISER_QP_MAX_REQ_DTOS) *   \

				 ISCSI_ISER_MAX_CONN)

static void iser_cq_tasklet_fn(unsigned long data);

static void iser_cq_callback(struct ib_cq *cq, void *cq_context);

static void iser_comp_error_worker(void *data);

static void iser_cq_event_callback(struct ib_event *cause, void *context)

{

	iser_err("got cq event %d \n", cause->event);

}

static void iser_qp_event_callback(struct ib_event *cause, void *context)

{

	iser_err("got qp event %d\n",cause->event);

}

/**

 * iser_create_device_ib_res - creates Protection Domain (PD), Completion

 * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with

 * the adapator.

 *

 * returns 0 on success, -1 on failure

 */

static int iser_create_device_ib_res(struct iser_device *device)

{

	device->pd = ib_alloc_pd(device->ib_device);

	if (IS_ERR(device->pd))

		goto pd_err;

	device->cq = ib_create_cq(device->ib_device,

				  iser_cq_callback,

				  iser_cq_event_callback,

				  (void *)device,

				  ISER_MAX_CQ_LEN);

	if (IS_ERR(device->cq))

		goto cq_err;

	if (ib_req_notify_cq(device->cq, IB_CQ_NEXT_COMP))

		goto cq_arm_err;

	tasklet_init(&device->cq_tasklet,

		     iser_cq_tasklet_fn,

		     (unsigned long)device);

	device->mr = ib_get_dma_mr(device->pd,

				   IB_ACCESS_LOCAL_WRITE);

	if (IS_ERR(device->mr))

		goto dma_mr_err;

	return 0;

dma_mr_err:

	tasklet_kill(&device->cq_tasklet);

cq_arm_err:

	ib_destroy_cq(device->cq);

cq_err:

	ib_dealloc_pd(device->pd);

pd_err:

	iser_err("failed to allocate an IB resource\n");

	return -1;

}

/**

 * iser_free_device_ib_res - destory/dealloc/dereg the DMA MR,

 * CQ and PD created with the device associated with the adapator.

 */

static void iser_free_device_ib_res(struct iser_device *device)

{

	BUG_ON(device->mr == NULL);

	tasklet_kill(&device->cq_tasklet);

	(void)ib_dereg_mr(device->mr);

	(void)ib_destroy_cq(device->cq);

	(void)ib_dealloc_pd(device->pd);

	device->mr = NULL;

	device->cq = NULL;

	device->pd = NULL;

}

/**

 * iser_create_ib_conn_res - Creates FMR pool and Queue-Pair (QP)

 *

 * returns 0 on success, -1 on failure

 */

static int iser_create_ib_conn_res(struct iser_conn *ib_conn)

{

	struct iser_device	*device;

	struct ib_qp_init_attr	init_attr;

	int			ret;

	struct ib_fmr_pool_param params;

	BUG_ON(ib_conn->device == NULL);

	device = ib_conn->device;

	ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +

				    (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),

				    GFP_KERNEL);

	if (!ib_conn->page_vec) {

		ret = -ENOMEM;

		goto alloc_err;

	}

	ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);

	params.page_shift        = PAGE_SHIFT;

	/* when the first/last SG element are not start/end *

	 * page aligned, the map whould be of N+1 pages     */

	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;

	/* make the pool size twice the max number of SCSI commands *

	 * the ML is expected to queue, watermark for unmap at 50%  */

	params.pool_size	 = ISCSI_XMIT_CMDS_MAX * 2;

	params.dirty_watermark	 = ISCSI_XMIT_CMDS_MAX;

	params.cache		 = 0;

	params.flush_function	 = NULL;

	params.access		 = (IB_ACCESS_LOCAL_WRITE  |

				    IB_ACCESS_REMOTE_WRITE |

				    IB_ACCESS_REMOTE_READ);

	ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);

	if (IS_ERR(ib_conn->fmr_pool)) {

		ret = PTR_ERR(ib_conn->fmr_pool);

		goto fmr_pool_err;

	}

	memset(&init_attr, 0, sizeof init_attr);

	init_attr.event_handler = iser_qp_event_callback;

	init_attr.qp_context	= (void *)ib_conn;

	init_attr.send_cq	= device->cq;

	init_attr.recv_cq	= device->cq;

	init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS;

	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;

	init_attr.cap.max_send_sge = MAX_REGD_BUF_VECTOR_LEN;

	init_attr.cap.max_recv_sge = 2;

	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;

	init_attr.qp_type	= IB_QPT_RC;

	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);

	if (ret)

		goto qp_err;

	ib_conn->qp = ib_conn->cma_id->qp;

	iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",

		 ib_conn, ib_conn->cma_id,

		 ib_conn->fmr_pool, ib_conn->cma_id->qp);

	return ret;

qp_err:

	(void)ib_destroy_fmr_pool(ib_conn->fmr_pool);

fmr_pool_err:

	kfree(ib_conn->page_vec);

alloc_err:

	iser_err("unable to alloc mem or create resource, err %d\n", ret);

	return ret;

}

/**

 * releases the FMR pool, QP and CMA ID objects, returns 0 on success,

 * -1 on failure

 */

static int iser_free_ib_conn_res(struct iser_conn *ib_conn)

{

	BUG_ON(ib_conn == NULL);

	iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",

		 ib_conn, ib_conn->cma_id,

		 ib_conn->fmr_pool, ib_conn->qp);

	/* qp is created only once both addr & route are resolved */

	if (ib_conn->fmr_pool != NULL)

		ib_destroy_fmr_pool(ib_conn->fmr_pool);

	if (ib_conn->qp != NULL)

		rdma_destroy_qp(ib_conn->cma_id);

	if (ib_conn->cma_id != NULL)

		rdma_destroy_id(ib_conn->cma_id);

	ib_conn->fmr_pool = NULL;

	ib_conn->qp	  = NULL;

	ib_conn->cma_id   = NULL;

	kfree(ib_conn->page_vec);

	return 0;

}

/**

 * based on the resolved device node GUID see if there already allocated

 * device for this device. If there's no such, create one.

 */

static

struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)

{

	struct list_head    *p_list;

	struct iser_device  *device = NULL;

	mutex_lock(&ig.device_list_mutex);

	p_list = ig.device_list.next;

	while (p_list != &ig.device_list) {

		device = list_entry(p_list, struct iser_device, ig_list);

		/* find if there's a match using the node GUID */

		if (device->ib_device->node_guid == cma_id->device->node_guid)

			break;

	}

	if (device == NULL) {

		device = kzalloc(sizeof *device, GFP_KERNEL);

		if (device == NULL)

			goto out;

		/* assign this device to the device */

		device->ib_device = cma_id->device;

		/* init the device and link it into ig device list */

		if (iser_create_device_ib_res(device)) {

			kfree(device);

			device = NULL;

			goto out;

		}

		list_add(&device->ig_list, &ig.device_list);

	}

out:

	BUG_ON(device == NULL);

	device->refcount++;

	mutex_unlock(&ig.device_list_mutex);

	return device;

}

/* if there's no demand for this device, release it */

static void iser_device_try_release(struct iser_device *device)

{

	mutex_lock(&ig.device_list_mutex);

	device->refcount--;

	iser_err("device %p refcount %d\n",device,device->refcount);

	if (!device->refcount) {

		iser_free_device_ib_res(device);

		list_del(&device->ig_list);

		kfree(device);

	}

	mutex_unlock(&ig.device_list_mutex);

}

int iser_conn_state_comp(struct iser_conn *ib_conn,

			enum iser_ib_conn_state comp)

{

	int ret;

	spin_lock_bh(&ib_conn->lock);

	ret = (ib_conn->state == comp);

	spin_unlock_bh(&ib_conn->lock);

	return ret;

}

static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,

				     enum iser_ib_conn_state comp,

				     enum iser_ib_conn_state exch)

{

	int ret;

	spin_lock_bh(&ib_conn->lock);

	if ((ret = (ib_conn->state == comp)))

		ib_conn->state = exch;

	spin_unlock_bh(&ib_conn->lock);

	return ret;

}

/**

 * triggers start of the disconnect procedures and wait for them to be done

 */

void iser_conn_terminate(struct iser_conn *ib_conn)

{

	int err = 0;

	/* change the ib conn state only if the conn is UP, however always call

	 * rdma_disconnect since this is the only way to cause the CMA to change

	 * the QP state to ERROR

	 */

	iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);

	err = rdma_disconnect(ib_conn->cma_id);

	if (err)

		iser_err("Failed to disconnect, conn: 0x%p err %d\n",

			 ib_conn,err);

	wait_event_interruptible(ib_conn->wait,

				 ib_conn->state == ISER_CONN_DOWN);

	iser_conn_release(ib_conn);

}

static void iser_connect_error(struct rdma_cm_id *cma_id)

{

	struct iser_conn *ib_conn;

	ib_conn = (struct iser_conn *)cma_id->context;

	ib_conn->state = ISER_CONN_DOWN;

	wake_up_interruptible(&ib_conn->wait);

}

static void iser_addr_handler(struct rdma_cm_id *cma_id)

{

	struct iser_device *device;

	struct iser_conn   *ib_conn;

	int    ret;

	device = iser_device_find_by_ib_device(cma_id);

	ib_conn = (struct iser_conn *)cma_id->context;

	ib_conn->device = device;

	ret = rdma_resolve_route(cma_id, 1000);

	if (ret) {

		iser_err("resolve route failed: %d\n", ret);

		iser_connect_error(cma_id);

	}

	return;

}

static void iser_route_handler(struct rdma_cm_id *cma_id)

{

	struct rdma_conn_param conn_param;

	int    ret;

	ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);

	if (ret)

		goto failure;

	iser_dbg("path.mtu is %d setting it to %d\n",

		 cma_id->route.path_rec->mtu, IB_MTU_1024);

	/* we must set the MTU to 1024 as this is what the target is assuming */

	if (cma_id->route.path_rec->mtu > IB_MTU_1024)

		cma_id->route.path_rec->mtu = IB_MTU_1024;

	memset(&conn_param, 0, sizeof conn_param);

	conn_param.responder_resources = 4;

	conn_param.initiator_depth     = 1;

	conn_param.retry_count	       = 7;

	conn_param.rnr_retry_count     = 6;

	ret = rdma_connect(cma_id, &conn_param);

	if (ret) {

		iser_err("failure connecting: %d\n", ret);

		goto failure;

	}

	return;

failure:

	iser_connect_error(cma_id);

}

static void iser_connected_handler(struct rdma_cm_id *cma_id)

{

	struct iser_conn *ib_conn;

	ib_conn = (struct iser_conn *)cma_id->context;

	ib_conn->state = ISER_CONN_UP;

	wake_up_interruptible(&ib_conn->wait);

}

static void iser_disconnected_handler(struct rdma_cm_id *cma_id)

{

	struct iser_conn *ib_conn;

	ib_conn = (struct iser_conn *)cma_id->context;

	ib_conn->disc_evt_flag = 1;

	/* getting here when the state is UP means that the conn is being *

	 * terminated asynchronously from the iSCSI layer's perspective.  */

	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,

				      ISER_CONN_TERMINATING))

		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,

				   ISCSI_ERR_CONN_FAILED);

	/* Complete the termination process if no posts are pending */

	if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&

	    (atomic_read(&ib_conn->post_send_buf_count) == 0)) {

		ib_conn->state = ISER_CONN_DOWN;

		wake_up_interruptible(&ib_conn->wait);

	}

}

static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)

{

	int ret = 0;

	iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);

	switch (event->event) {

	case RDMA_CM_EVENT_ADDR_RESOLVED:

		iser_addr_handler(cma_id);

		break;

	case RDMA_CM_EVENT_ROUTE_RESOLVED:

		iser_route_handler(cma_id);

		break;

	case RDMA_CM_EVENT_ESTABLISHED:

		iser_connected_handler(cma_id);

		break;

	case RDMA_CM_EVENT_ADDR_ERROR:

	case RDMA_CM_EVENT_ROUTE_ERROR:

	case RDMA_CM_EVENT_CONNECT_ERROR:

	case RDMA_CM_EVENT_UNREACHABLE:

	case RDMA_CM_EVENT_REJECTED:

		iser_err("event: %d, error: %d\n", event->event, event->status);

		iser_connect_error(cma_id);

		break;

	case RDMA_CM_EVENT_DISCONNECTED:

		iser_disconnected_handler(cma_id);

		break;

	case RDMA_CM_EVENT_DEVICE_REMOVAL:

		BUG();

		break;

	case RDMA_CM_EVENT_CONNECT_RESPONSE:

		BUG();

		break;

	case RDMA_CM_EVENT_CONNECT_REQUEST:

	default:

		break;

	}

	return ret;

}

int iser_conn_init(struct iser_conn **ibconn)

{

	struct iser_conn *ib_conn;

	ib_conn = kzalloc(sizeof *ib_conn, GFP_KERNEL);

	if (!ib_conn) {

		iser_err("can't alloc memory for struct iser_conn\n");

		return -ENOMEM;

	}

	ib_conn->state = ISER_CONN_INIT;

	init_waitqueue_head(&ib_conn->wait);

	atomic_set(&ib_conn->post_recv_buf_count, 0);

	atomic_set(&ib_conn->post_send_buf_count, 0);

	INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker,

		  ib_conn);

	INIT_LIST_HEAD(&ib_conn->conn_list);

	spin_lock_init(&ib_conn->lock);

	*ibconn = ib_conn;

	return 0;

}

 /**

 * starts the process of connecting to the target

 * sleeps untill the connection is established or rejected

 */

int iser_connect(struct iser_conn   *ib_conn,

		 struct sockaddr_in *src_addr,

		 struct sockaddr_in *dst_addr,

		 int                 non_blocking)

{

	struct sockaddr *src, *dst;

	int err = 0;

	sprintf(ib_conn->name,"%d.%d.%d.%d:%d",

		NIPQUAD(dst_addr->sin_addr.s_addr), dst_addr->sin_port);

	/* the device is known only --after-- address resolution */

	ib_conn->device = NULL;

	iser_err("connecting to: %d.%d.%d.%d, port 0x%x\n",

		 NIPQUAD(dst_addr->sin_addr), dst_addr->sin_port);

	ib_conn->state = ISER_CONN_PENDING;

	ib_conn->cma_id = rdma_create_id(iser_cma_handler,

					     (void *)ib_conn,

					     RDMA_PS_TCP);

	if (IS_ERR(ib_conn->cma_id)) {

		err = PTR_ERR(ib_conn->cma_id);

		iser_err("rdma_create_id failed: %d\n", err);

		goto id_failure;

	}

	src = (struct sockaddr *)src_addr;

	dst = (struct sockaddr *)dst_addr;

	err = rdma_resolve_addr(ib_conn->cma_id, src, dst, 1000);

	if (err) {

		iser_err("rdma_resolve_addr failed: %d\n", err);

		goto addr_failure;

	}

	if (!non_blocking) {

		wait_event_interruptible(ib_conn->wait,

					 (ib_conn->state != ISER_CONN_PENDING));

		if (ib_conn->state != ISER_CONN_UP) {

			err =  -EIO;

			goto connect_failure;

		}

	}

	mutex_lock(&ig.connlist_mutex);

	list_add(&ib_conn->conn_list, &ig.connlist);

	mutex_unlock(&ig.connlist_mutex);

	return 0;

id_failure:

	ib_conn->cma_id = NULL;

addr_failure:

	ib_conn->state = ISER_CONN_DOWN;

connect_failure:

	iser_conn_release(ib_conn);

	return err;

}

/**

 * Frees all conn objects and deallocs conn descriptor

 */

void iser_conn_release(struct iser_conn *ib_conn)

{

	struct iser_device  *device = ib_conn->device;

	BUG_ON(ib_conn->state != ISER_CONN_DOWN);

	mutex_lock(&ig.connlist_mutex);

	list_del(&ib_conn->conn_list);

	mutex_unlock(&ig.connlist_mutex);

	iser_free_ib_conn_res(ib_conn);

	ib_conn->device = NULL;

	/* on EVENT_ADDR_ERROR there's no device yet for this conn */

	if (device != NULL)

		iser_device_try_release(device);

	kfree(ib_conn);

}

/**

 * iser_reg_page_vec - Register physical memory

 *

 * returns: 0 on success, errno code on failure

 */

int iser_reg_page_vec(struct iser_conn     *ib_conn,

		      struct iser_page_vec *page_vec,

		      struct iser_mem_reg  *mem_reg)

{

	struct ib_pool_fmr *mem;

	u64		   io_addr;

	u64		   *page_list;

	int		   status;

	page_list = page_vec->pages;

	io_addr	  = page_list[0];

	mem  = ib_fmr_pool_map_phys(ib_conn->fmr_pool,

				    page_list,

				    page_vec->length,

				    &io_addr);

	if (IS_ERR(mem)) {

		status = (int)PTR_ERR(mem);

		iser_err("ib_fmr_pool_map_phys failed: %d\n", status);

		return status;

	}

	mem_reg->lkey  = mem->fmr->lkey;

	mem_reg->rkey  = mem->fmr->rkey;

	mem_reg->len   = page_vec->length * PAGE_SIZE;

	mem_reg->va    = io_addr;

	mem_reg->mem_h = (void *)mem;

	mem_reg->va   += page_vec->offset;

	mem_reg->len   = page_vec->data_size;

	iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "

		 "entry[0]: (0x%08lx,%ld)] -> "

		 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",

		 page_vec, page_vec->length,

		 (unsigned long)page_vec->pages[0],

		 (unsigned long)page_vec->data_size,

		 (unsigned int)mem_reg->lkey, mem_reg->mem_h,

		 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);

	return 0;

}

/**

 * Unregister (previosuly registered) memory.

 */

void iser_unreg_mem(struct iser_mem_reg *reg)

{

	int ret;

	iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);

	ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);

	if (ret)

		iser_err("ib_fmr_pool_unmap failed %d\n", ret);

	reg->mem_h = NULL;

}

/**

 * iser_dto_to_iov - builds IOV from a dto descriptor

 */

static void iser_dto_to_iov(struct iser_dto *dto, struct ib_sge *iov, int iov_len)

{

	int		     i;

	struct ib_sge	     *sge;

	struct iser_regd_buf *regd_buf;

	if (dto->regd_vector_len > iov_len) {

		iser_err("iov size %d too small for posting dto of len %d\n",

			 iov_len, dto->regd_vector_len);

		BUG();

	}

	for (i = 0; i < dto->regd_vector_len; i++) {

		sge	    = &iov[i];

		regd_buf  = dto->regd[i];

		sge->addr   = regd_buf->reg.va;

		sge->length = regd_buf->reg.len;

		sge->lkey   = regd_buf->reg.lkey;

		if (dto->used_sz[i] > 0)  /* Adjust size */

			sge->length = dto->used_sz[i];

		/* offset and length should not exceed the regd buf length */

		if (sge->length + dto->offset[i] > regd_buf->reg.len) {

			iser_err("Used len:%ld + offset:%d, exceed reg.buf.len:"

				 "%ld in dto:0x%p [%d], va:0x%08lX\n",

				 (unsigned long)sge->length, dto->offset[i],

				 (unsigned long)regd_buf->reg.len, dto, i,

				 (unsigned long)sge->addr);

			BUG();

		}

		sge->addr += dto->offset[i]; /* Adjust offset */

	}

}

/**

 * iser_post_recv - Posts a receive buffer.

 *

 * returns 0 on success, -1 on failure

 */

int iser_post_recv(struct iser_desc *rx_desc)

{

	int		  ib_ret, ret_val = 0;

	struct ib_recv_wr recv_wr, *recv_wr_failed;

	struct ib_sge	  iov[2];

	struct iser_conn  *ib_conn;

	struct iser_dto   *recv_dto = &rx_desc->dto;

	/* Retrieve conn */

	ib_conn = recv_dto->conn->ib_conn;

	iser_dto_to_iov(recv_dto, iov, 2);

	recv_wr.next	= NULL;

	recv_wr.sg_list = iov;

	recv_wr.num_sge = recv_dto->regd_vector_len;

	recv_wr.wr_id	= (unsigned long)rx_desc;

	atomic_inc(&ib_conn->post_recv_buf_count);

	ib_ret	= ib_post_recv(ib_conn->qp, &recv_wr, &recv_wr_failed);

	if (ib_ret) {

		iser_err("ib_post_recv failed ret=%d\n", ib_ret);

		atomic_dec(&ib_conn->post_recv_buf_count);

		ret_val = -1;

	}

	return ret_val;