xref: /linux/drivers/infiniband/ulp/iser/iser_verbs.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *	- Redistributions of source code must retain the above
16  *	  copyright notice, this list of conditions and the following
17  *	  disclaimer.
18  *
19  *	- Redistributions in binary form must reproduce the above
20  *	  copyright notice, this list of conditions and the following
21  *	  disclaimer in the documentation and/or other materials
22  *	  provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  *
33  * $Id: iser_verbs.c 7051 2006-05-10 12:29:11Z ogerlitz $
34  */
35 #include <asm/io.h>
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/smp_lock.h>
39 #include <linux/delay.h>
40 #include <linux/version.h>
41 
42 #include "iscsi_iser.h"
43 
44 #define ISCSI_ISER_MAX_CONN	8
45 #define ISER_MAX_CQ_LEN		((ISER_QP_MAX_RECV_DTOS + \
46 				ISER_QP_MAX_REQ_DTOS) *   \
47 				 ISCSI_ISER_MAX_CONN)
48 
49 static void iser_cq_tasklet_fn(unsigned long data);
50 static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
51 static void iser_comp_error_worker(struct work_struct *work);
52 
53 static void iser_cq_event_callback(struct ib_event *cause, void *context)
54 {
55 	iser_err("got cq event %d \n", cause->event);
56 }
57 
58 static void iser_qp_event_callback(struct ib_event *cause, void *context)
59 {
60 	iser_err("got qp event %d\n",cause->event);
61 }
62 
63 /**
64  * iser_create_device_ib_res - creates Protection Domain (PD), Completion
65  * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
66  * the adapator.
67  *
68  * returns 0 on success, -1 on failure
69  */
70 static int iser_create_device_ib_res(struct iser_device *device)
71 {
72 	device->pd = ib_alloc_pd(device->ib_device);
73 	if (IS_ERR(device->pd))
74 		goto pd_err;
75 
76 	device->cq = ib_create_cq(device->ib_device,
77 				  iser_cq_callback,
78 				  iser_cq_event_callback,
79 				  (void *)device,
80 				  ISER_MAX_CQ_LEN);
81 	if (IS_ERR(device->cq))
82 		goto cq_err;
83 
84 	if (ib_req_notify_cq(device->cq, IB_CQ_NEXT_COMP))
85 		goto cq_arm_err;
86 
87 	tasklet_init(&device->cq_tasklet,
88 		     iser_cq_tasklet_fn,
89 		     (unsigned long)device);
90 
91 	device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
92 				   IB_ACCESS_REMOTE_WRITE |
93 				   IB_ACCESS_REMOTE_READ);
94 	if (IS_ERR(device->mr))
95 		goto dma_mr_err;
96 
97 	return 0;
98 
99 dma_mr_err:
100 	tasklet_kill(&device->cq_tasklet);
101 cq_arm_err:
102 	ib_destroy_cq(device->cq);
103 cq_err:
104 	ib_dealloc_pd(device->pd);
105 pd_err:
106 	iser_err("failed to allocate an IB resource\n");
107 	return -1;
108 }
109 
110 /**
111  * iser_free_device_ib_res - destory/dealloc/dereg the DMA MR,
112  * CQ and PD created with the device associated with the adapator.
113  */
114 static void iser_free_device_ib_res(struct iser_device *device)
115 {
116 	BUG_ON(device->mr == NULL);
117 
118 	tasklet_kill(&device->cq_tasklet);
119 
120 	(void)ib_dereg_mr(device->mr);
121 	(void)ib_destroy_cq(device->cq);
122 	(void)ib_dealloc_pd(device->pd);
123 
124 	device->mr = NULL;
125 	device->cq = NULL;
126 	device->pd = NULL;
127 }
128 
129 /**
130  * iser_create_ib_conn_res - Creates FMR pool and Queue-Pair (QP)
131  *
132  * returns 0 on success, -1 on failure
133  */
134 static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
135 {
136 	struct iser_device	*device;
137 	struct ib_qp_init_attr	init_attr;
138 	int			ret;
139 	struct ib_fmr_pool_param params;
140 
141 	BUG_ON(ib_conn->device == NULL);
142 
143 	device = ib_conn->device;
144 
145 	ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
146 				    (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
147 				    GFP_KERNEL);
148 	if (!ib_conn->page_vec) {
149 		ret = -ENOMEM;
150 		goto alloc_err;
151 	}
152 	ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
153 
154 	params.page_shift        = SHIFT_4K;
155 	/* when the first/last SG element are not start/end *
156 	 * page aligned, the map whould be of N+1 pages     */
157 	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
158 	/* make the pool size twice the max number of SCSI commands *
159 	 * the ML is expected to queue, watermark for unmap at 50%  */
160 	params.pool_size	 = ISCSI_XMIT_CMDS_MAX * 2;
161 	params.dirty_watermark	 = ISCSI_XMIT_CMDS_MAX;
162 	params.cache		 = 0;
163 	params.flush_function	 = NULL;
164 	params.access		 = (IB_ACCESS_LOCAL_WRITE  |
165 				    IB_ACCESS_REMOTE_WRITE |
166 				    IB_ACCESS_REMOTE_READ);
167 
168 	ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);
169 	if (IS_ERR(ib_conn->fmr_pool)) {
170 		ret = PTR_ERR(ib_conn->fmr_pool);
171 		goto fmr_pool_err;
172 	}
173 
174 	memset(&init_attr, 0, sizeof init_attr);
175 
176 	init_attr.event_handler = iser_qp_event_callback;
177 	init_attr.qp_context	= (void *)ib_conn;
178 	init_attr.send_cq	= device->cq;
179 	init_attr.recv_cq	= device->cq;
180 	init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS;
181 	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
182 	init_attr.cap.max_send_sge = MAX_REGD_BUF_VECTOR_LEN;
183 	init_attr.cap.max_recv_sge = 2;
184 	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;
185 	init_attr.qp_type	= IB_QPT_RC;
186 
187 	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
188 	if (ret)
189 		goto qp_err;
190 
191 	ib_conn->qp = ib_conn->cma_id->qp;
192 	iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",
193 		 ib_conn, ib_conn->cma_id,
194 		 ib_conn->fmr_pool, ib_conn->cma_id->qp);
195 	return ret;
196 
197 qp_err:
198 	(void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
199 fmr_pool_err:
200 	kfree(ib_conn->page_vec);
201 alloc_err:
202 	iser_err("unable to alloc mem or create resource, err %d\n", ret);
203 	return ret;
204 }
205 
206 /**
207  * releases the FMR pool, QP and CMA ID objects, returns 0 on success,
208  * -1 on failure
209  */
210 static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
211 {
212 	BUG_ON(ib_conn == NULL);
213 
214 	iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",
215 		 ib_conn, ib_conn->cma_id,
216 		 ib_conn->fmr_pool, ib_conn->qp);
217 
218 	/* qp is created only once both addr & route are resolved */
219 	if (ib_conn->fmr_pool != NULL)
220 		ib_destroy_fmr_pool(ib_conn->fmr_pool);
221 
222 	if (ib_conn->qp != NULL)
223 		rdma_destroy_qp(ib_conn->cma_id);
224 
225 	if (ib_conn->cma_id != NULL)
226 		rdma_destroy_id(ib_conn->cma_id);
227 
228 	ib_conn->fmr_pool = NULL;
229 	ib_conn->qp	  = NULL;
230 	ib_conn->cma_id   = NULL;
231 	kfree(ib_conn->page_vec);
232 
233 	return 0;
234 }
235 
236 /**
237  * based on the resolved device node GUID see if there already allocated
238  * device for this device. If there's no such, create one.
239  */
240 static
241 struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
242 {
243 	struct list_head    *p_list;
244 	struct iser_device  *device = NULL;
245 
246 	mutex_lock(&ig.device_list_mutex);
247 
248 	p_list = ig.device_list.next;
249 	while (p_list != &ig.device_list) {
250 		device = list_entry(p_list, struct iser_device, ig_list);
251 		/* find if there's a match using the node GUID */
252 		if (device->ib_device->node_guid == cma_id->device->node_guid)
253 			break;
254 	}
255 
256 	if (device == NULL) {
257 		device = kzalloc(sizeof *device, GFP_KERNEL);
258 		if (device == NULL)
259 			goto out;
260 		/* assign this device to the device */
261 		device->ib_device = cma_id->device;
262 		/* init the device and link it into ig device list */
263 		if (iser_create_device_ib_res(device)) {
264 			kfree(device);
265 			device = NULL;
266 			goto out;
267 		}
268 		list_add(&device->ig_list, &ig.device_list);
269 	}
270 out:
271 	BUG_ON(device == NULL);
272 	device->refcount++;
273 	mutex_unlock(&ig.device_list_mutex);
274 	return device;
275 }
276 
277 /* if there's no demand for this device, release it */
278 static void iser_device_try_release(struct iser_device *device)
279 {
280 	mutex_lock(&ig.device_list_mutex);
281 	device->refcount--;
282 	iser_err("device %p refcount %d\n",device,device->refcount);
283 	if (!device->refcount) {
284 		iser_free_device_ib_res(device);
285 		list_del(&device->ig_list);
286 		kfree(device);
287 	}
288 	mutex_unlock(&ig.device_list_mutex);
289 }
290 
291 int iser_conn_state_comp(struct iser_conn *ib_conn,
292 			enum iser_ib_conn_state comp)
293 {
294 	int ret;
295 
296 	spin_lock_bh(&ib_conn->lock);
297 	ret = (ib_conn->state == comp);
298 	spin_unlock_bh(&ib_conn->lock);
299 	return ret;
300 }
301 
302 static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
303 				     enum iser_ib_conn_state comp,
304 				     enum iser_ib_conn_state exch)
305 {
306 	int ret;
307 
308 	spin_lock_bh(&ib_conn->lock);
309 	if ((ret = (ib_conn->state == comp)))
310 		ib_conn->state = exch;
311 	spin_unlock_bh(&ib_conn->lock);
312 	return ret;
313 }
314 
315 /**
316  * triggers start of the disconnect procedures and wait for them to be done
317  */
318 void iser_conn_terminate(struct iser_conn *ib_conn)
319 {
320 	int err = 0;
321 
322 	/* change the ib conn state only if the conn is UP, however always call
323 	 * rdma_disconnect since this is the only way to cause the CMA to change
324 	 * the QP state to ERROR
325 	 */
326 
327 	iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
328 	err = rdma_disconnect(ib_conn->cma_id);
329 	if (err)
330 		iser_err("Failed to disconnect, conn: 0x%p err %d\n",
331 			 ib_conn,err);
332 
333 	wait_event_interruptible(ib_conn->wait,
334 				 ib_conn->state == ISER_CONN_DOWN);
335 
336 	iser_conn_release(ib_conn);
337 }
338 
339 static void iser_connect_error(struct rdma_cm_id *cma_id)
340 {
341 	struct iser_conn *ib_conn;
342 	ib_conn = (struct iser_conn *)cma_id->context;
343 
344 	ib_conn->state = ISER_CONN_DOWN;
345 	wake_up_interruptible(&ib_conn->wait);
346 }
347 
348 static void iser_addr_handler(struct rdma_cm_id *cma_id)
349 {
350 	struct iser_device *device;
351 	struct iser_conn   *ib_conn;
352 	int    ret;
353 
354 	device = iser_device_find_by_ib_device(cma_id);
355 	ib_conn = (struct iser_conn *)cma_id->context;
356 	ib_conn->device = device;
357 
358 	ret = rdma_resolve_route(cma_id, 1000);
359 	if (ret) {
360 		iser_err("resolve route failed: %d\n", ret);
361 		iser_connect_error(cma_id);
362 	}
363 	return;
364 }
365 
366 static void iser_route_handler(struct rdma_cm_id *cma_id)
367 {
368 	struct rdma_conn_param conn_param;
369 	int    ret;
370 
371 	ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
372 	if (ret)
373 		goto failure;
374 
375 	iser_dbg("path.mtu is %d setting it to %d\n",
376 		 cma_id->route.path_rec->mtu, IB_MTU_1024);
377 
378 	/* we must set the MTU to 1024 as this is what the target is assuming */
379 	if (cma_id->route.path_rec->mtu > IB_MTU_1024)
380 		cma_id->route.path_rec->mtu = IB_MTU_1024;
381 
382 	memset(&conn_param, 0, sizeof conn_param);
383 	conn_param.responder_resources = 4;
384 	conn_param.initiator_depth     = 1;
385 	conn_param.retry_count	       = 7;
386 	conn_param.rnr_retry_count     = 6;
387 
388 	ret = rdma_connect(cma_id, &conn_param);
389 	if (ret) {
390 		iser_err("failure connecting: %d\n", ret);
391 		goto failure;
392 	}
393 
394 	return;
395 failure:
396 	iser_connect_error(cma_id);
397 }
398 
399 static void iser_connected_handler(struct rdma_cm_id *cma_id)
400 {
401 	struct iser_conn *ib_conn;
402 
403 	ib_conn = (struct iser_conn *)cma_id->context;
404 	ib_conn->state = ISER_CONN_UP;
405 	wake_up_interruptible(&ib_conn->wait);
406 }
407 
408 static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
409 {
410 	struct iser_conn *ib_conn;
411 
412 	ib_conn = (struct iser_conn *)cma_id->context;
413 	ib_conn->disc_evt_flag = 1;
414 
415 	/* getting here when the state is UP means that the conn is being *
416 	 * terminated asynchronously from the iSCSI layer's perspective.  */
417 	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
418 				      ISER_CONN_TERMINATING))
419 		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
420 				   ISCSI_ERR_CONN_FAILED);
421 
422 	/* Complete the termination process if no posts are pending */
423 	if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&
424 	    (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
425 		ib_conn->state = ISER_CONN_DOWN;
426 		wake_up_interruptible(&ib_conn->wait);
427 	}
428 }
429 
430 static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
431 {
432 	int ret = 0;
433 
434 	iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);
435 
436 	switch (event->event) {
437 	case RDMA_CM_EVENT_ADDR_RESOLVED:
438 		iser_addr_handler(cma_id);
439 		break;
440 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
441 		iser_route_handler(cma_id);
442 		break;
443 	case RDMA_CM_EVENT_ESTABLISHED:
444 		iser_connected_handler(cma_id);
445 		break;
446 	case RDMA_CM_EVENT_ADDR_ERROR:
447 	case RDMA_CM_EVENT_ROUTE_ERROR:
448 	case RDMA_CM_EVENT_CONNECT_ERROR:
449 	case RDMA_CM_EVENT_UNREACHABLE:
450 	case RDMA_CM_EVENT_REJECTED:
451 		iser_err("event: %d, error: %d\n", event->event, event->status);
452 		iser_connect_error(cma_id);
453 		break;
454 	case RDMA_CM_EVENT_DISCONNECTED:
455 		iser_disconnected_handler(cma_id);
456 		break;
457 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
458 		BUG();
459 		break;
460 	case RDMA_CM_EVENT_CONNECT_RESPONSE:
461 		BUG();
462 		break;
463 	case RDMA_CM_EVENT_CONNECT_REQUEST:
464 	default:
465 		break;
466 	}
467 	return ret;
468 }
469 
470 int iser_conn_init(struct iser_conn **ibconn)
471 {
472 	struct iser_conn *ib_conn;
473 
474 	ib_conn = kzalloc(sizeof *ib_conn, GFP_KERNEL);
475 	if (!ib_conn) {
476 		iser_err("can't alloc memory for struct iser_conn\n");
477 		return -ENOMEM;
478 	}
479 	ib_conn->state = ISER_CONN_INIT;
480 	init_waitqueue_head(&ib_conn->wait);
481 	atomic_set(&ib_conn->post_recv_buf_count, 0);
482 	atomic_set(&ib_conn->post_send_buf_count, 0);
483 	INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker);
484 	INIT_LIST_HEAD(&ib_conn->conn_list);
485 	spin_lock_init(&ib_conn->lock);
486 
487 	*ibconn = ib_conn;
488 	return 0;
489 }
490 
491  /**
492  * starts the process of connecting to the target
493  * sleeps untill the connection is established or rejected
494  */
495 int iser_connect(struct iser_conn   *ib_conn,
496 		 struct sockaddr_in *src_addr,
497 		 struct sockaddr_in *dst_addr,
498 		 int                 non_blocking)
499 {
500 	struct sockaddr *src, *dst;
501 	int err = 0;
502 
503 	sprintf(ib_conn->name,"%d.%d.%d.%d:%d",
504 		NIPQUAD(dst_addr->sin_addr.s_addr), dst_addr->sin_port);
505 
506 	/* the device is known only --after-- address resolution */
507 	ib_conn->device = NULL;
508 
509 	iser_err("connecting to: %d.%d.%d.%d, port 0x%x\n",
510 		 NIPQUAD(dst_addr->sin_addr), dst_addr->sin_port);
511 
512 	ib_conn->state = ISER_CONN_PENDING;
513 
514 	ib_conn->cma_id = rdma_create_id(iser_cma_handler,
515 					     (void *)ib_conn,
516 					     RDMA_PS_TCP);
517 	if (IS_ERR(ib_conn->cma_id)) {
518 		err = PTR_ERR(ib_conn->cma_id);
519 		iser_err("rdma_create_id failed: %d\n", err);
520 		goto id_failure;
521 	}
522 
523 	src = (struct sockaddr *)src_addr;
524 	dst = (struct sockaddr *)dst_addr;
525 	err = rdma_resolve_addr(ib_conn->cma_id, src, dst, 1000);
526 	if (err) {
527 		iser_err("rdma_resolve_addr failed: %d\n", err);
528 		goto addr_failure;
529 	}
530 
531 	if (!non_blocking) {
532 		wait_event_interruptible(ib_conn->wait,
533 					 (ib_conn->state != ISER_CONN_PENDING));
534 
535 		if (ib_conn->state != ISER_CONN_UP) {
536 			err =  -EIO;
537 			goto connect_failure;
538 		}
539 	}
540 
541 	mutex_lock(&ig.connlist_mutex);
542 	list_add(&ib_conn->conn_list, &ig.connlist);
543 	mutex_unlock(&ig.connlist_mutex);
544 	return 0;
545 
546 id_failure:
547 	ib_conn->cma_id = NULL;
548 addr_failure:
549 	ib_conn->state = ISER_CONN_DOWN;
550 connect_failure:
551 	iser_conn_release(ib_conn);
552 	return err;
553 }
554 
555 /**
556  * Frees all conn objects and deallocs conn descriptor
557  */
558 void iser_conn_release(struct iser_conn *ib_conn)
559 {
560 	struct iser_device  *device = ib_conn->device;
561 
562 	BUG_ON(ib_conn->state != ISER_CONN_DOWN);
563 
564 	mutex_lock(&ig.connlist_mutex);
565 	list_del(&ib_conn->conn_list);
566 	mutex_unlock(&ig.connlist_mutex);
567 
568 	iser_free_ib_conn_res(ib_conn);
569 	ib_conn->device = NULL;
570 	/* on EVENT_ADDR_ERROR there's no device yet for this conn */
571 	if (device != NULL)
572 		iser_device_try_release(device);
573 	if (ib_conn->iser_conn)
574 		ib_conn->iser_conn->ib_conn = NULL;
575 	kfree(ib_conn);
576 }
577 
578 
579 /**
580  * iser_reg_page_vec - Register physical memory
581  *
582  * returns: 0 on success, errno code on failure
583  */
584 int iser_reg_page_vec(struct iser_conn     *ib_conn,
585 		      struct iser_page_vec *page_vec,
586 		      struct iser_mem_reg  *mem_reg)
587 {
588 	struct ib_pool_fmr *mem;
589 	u64		   io_addr;
590 	u64		   *page_list;
591 	int		   status;
592 
593 	page_list = page_vec->pages;
594 	io_addr	  = page_list[0];
595 
596 	mem  = ib_fmr_pool_map_phys(ib_conn->fmr_pool,
597 				    page_list,
598 				    page_vec->length,
599 				    io_addr);
600 
601 	if (IS_ERR(mem)) {
602 		status = (int)PTR_ERR(mem);
603 		iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
604 		return status;
605 	}
606 
607 	mem_reg->lkey  = mem->fmr->lkey;
608 	mem_reg->rkey  = mem->fmr->rkey;
609 	mem_reg->len   = page_vec->length * SIZE_4K;
610 	mem_reg->va    = io_addr;
611 	mem_reg->is_fmr = 1;
612 	mem_reg->mem_h = (void *)mem;
613 
614 	mem_reg->va   += page_vec->offset;
615 	mem_reg->len   = page_vec->data_size;
616 
617 	iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
618 		 "entry[0]: (0x%08lx,%ld)] -> "
619 		 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
620 		 page_vec, page_vec->length,
621 		 (unsigned long)page_vec->pages[0],
622 		 (unsigned long)page_vec->data_size,
623 		 (unsigned int)mem_reg->lkey, mem_reg->mem_h,
624 		 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
625 	return 0;
626 }
627 
628 /**
629  * Unregister (previosuly registered) memory.
630  */
631 void iser_unreg_mem(struct iser_mem_reg *reg)
632 {
633 	int ret;
634 
635 	iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
636 
637 	ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
638 	if (ret)
639 		iser_err("ib_fmr_pool_unmap failed %d\n", ret);
640 
641 	reg->mem_h = NULL;
642 }
643 
644 /**
645  * iser_dto_to_iov - builds IOV from a dto descriptor
646  */
647 static void iser_dto_to_iov(struct iser_dto *dto, struct ib_sge *iov, int iov_len)
648 {
649 	int		     i;
650 	struct ib_sge	     *sge;
651 	struct iser_regd_buf *regd_buf;
652 
653 	if (dto->regd_vector_len > iov_len) {
654 		iser_err("iov size %d too small for posting dto of len %d\n",
655 			 iov_len, dto->regd_vector_len);
656 		BUG();
657 	}
658 
659 	for (i = 0; i < dto->regd_vector_len; i++) {
660 		sge	    = &iov[i];
661 		regd_buf  = dto->regd[i];
662 
663 		sge->addr   = regd_buf->reg.va;
664 		sge->length = regd_buf->reg.len;
665 		sge->lkey   = regd_buf->reg.lkey;
666 
667 		if (dto->used_sz[i] > 0)  /* Adjust size */
668 			sge->length = dto->used_sz[i];
669 
670 		/* offset and length should not exceed the regd buf length */
671 		if (sge->length + dto->offset[i] > regd_buf->reg.len) {
672 			iser_err("Used len:%ld + offset:%d, exceed reg.buf.len:"
673 				 "%ld in dto:0x%p [%d], va:0x%08lX\n",
674 				 (unsigned long)sge->length, dto->offset[i],
675 				 (unsigned long)regd_buf->reg.len, dto, i,
676 				 (unsigned long)sge->addr);
677 			BUG();
678 		}
679 
680 		sge->addr += dto->offset[i]; /* Adjust offset */
681 	}
682 }
683 
684 /**
685  * iser_post_recv - Posts a receive buffer.
686  *
687  * returns 0 on success, -1 on failure
688  */
689 int iser_post_recv(struct iser_desc *rx_desc)
690 {
691 	int		  ib_ret, ret_val = 0;
692 	struct ib_recv_wr recv_wr, *recv_wr_failed;
693 	struct ib_sge	  iov[2];
694 	struct iser_conn  *ib_conn;
695 	struct iser_dto   *recv_dto = &rx_desc->dto;
696 
697 	/* Retrieve conn */
698 	ib_conn = recv_dto->ib_conn;
699 
700 	iser_dto_to_iov(recv_dto, iov, 2);
701 
702 	recv_wr.next	= NULL;
703 	recv_wr.sg_list = iov;
704 	recv_wr.num_sge = recv_dto->regd_vector_len;
705 	recv_wr.wr_id	= (unsigned long)rx_desc;
706 
707 	atomic_inc(&ib_conn->post_recv_buf_count);
708 	ib_ret	= ib_post_recv(ib_conn->qp, &recv_wr, &recv_wr_failed);
709 	if (ib_ret) {
710 		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
711 		atomic_dec(&ib_conn->post_recv_buf_count);
712 		ret_val = -1;
713 	}
714 
715 	return ret_val;
716 }
717 
718 /**
719  * iser_start_send - Initiate a Send DTO operation
720  *
721  * returns 0 on success, -1 on failure
722  */
723 int iser_post_send(struct iser_desc *tx_desc)
724 {
725 	int		  ib_ret, ret_val = 0;
726 	struct ib_send_wr send_wr, *send_wr_failed;
727 	struct ib_sge	  iov[MAX_REGD_BUF_VECTOR_LEN];
728 	struct iser_conn  *ib_conn;
729 	struct iser_dto   *dto = &tx_desc->dto;
730 
731 	ib_conn = dto->ib_conn;
732 
733 	iser_dto_to_iov(dto, iov, MAX_REGD_BUF_VECTOR_LEN);
734 
735 	send_wr.next	   = NULL;
736 	send_wr.wr_id	   = (unsigned long)tx_desc;
737 	send_wr.sg_list	   = iov;
738 	send_wr.num_sge	   = dto->regd_vector_len;
739 	send_wr.opcode	   = IB_WR_SEND;
740 	send_wr.send_flags = dto->notify_enable ? IB_SEND_SIGNALED : 0;
741 
742 	atomic_inc(&ib_conn->post_send_buf_count);
743 
744 	ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
745 	if (ib_ret) {
746 		iser_err("Failed to start SEND DTO, dto: 0x%p, IOV len: %d\n",
747 			 dto, dto->regd_vector_len);
748 		iser_err("ib_post_send failed, ret:%d\n", ib_ret);
749 		atomic_dec(&ib_conn->post_send_buf_count);
750 		ret_val = -1;
751 	}
752 
753 	return ret_val;
754 }
755 
756 static void iser_comp_error_worker(struct work_struct *work)
757 {
758 	struct iser_conn *ib_conn =
759 		container_of(work, struct iser_conn, comperror_work);
760 
761 	/* getting here when the state is UP means that the conn is being *
762 	 * terminated asynchronously from the iSCSI layer's perspective.  */
763 	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
764 				      ISER_CONN_TERMINATING))
765 		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
766 					ISCSI_ERR_CONN_FAILED);
767 
768 	/* complete the termination process if disconnect event was delivered *
769 	 * note there are no more non completed posts to the QP               */
770 	if (ib_conn->disc_evt_flag) {
771 		ib_conn->state = ISER_CONN_DOWN;
772 		wake_up_interruptible(&ib_conn->wait);
773 	}
774 }
775 
776 static void iser_handle_comp_error(struct iser_desc *desc)
777 {
778 	struct iser_dto  *dto     = &desc->dto;
779 	struct iser_conn *ib_conn = dto->ib_conn;
780 
781 	iser_dto_buffs_release(dto);
782 
783 	if (desc->type == ISCSI_RX) {
784 		kfree(desc->data);
785 		kmem_cache_free(ig.desc_cache, desc);
786 		atomic_dec(&ib_conn->post_recv_buf_count);
787 	} else { /* type is TX control/command/dataout */
788 		if (desc->type == ISCSI_TX_DATAOUT)
789 			kmem_cache_free(ig.desc_cache, desc);
790 		atomic_dec(&ib_conn->post_send_buf_count);
791 	}
792 
793 	if (atomic_read(&ib_conn->post_recv_buf_count) == 0 &&
794 	    atomic_read(&ib_conn->post_send_buf_count) == 0)
795 		schedule_work(&ib_conn->comperror_work);
796 }
797 
798 static void iser_cq_tasklet_fn(unsigned long data)
799 {
800 	 struct iser_device  *device = (struct iser_device *)data;
801 	 struct ib_cq	     *cq = device->cq;
802 	 struct ib_wc	     wc;
803 	 struct iser_desc    *desc;
804 	 unsigned long	     xfer_len;
805 
806 	while (ib_poll_cq(cq, 1, &wc) == 1) {
807 		desc	 = (struct iser_desc *) (unsigned long) wc.wr_id;
808 		BUG_ON(desc == NULL);
809 
810 		if (wc.status == IB_WC_SUCCESS) {
811 			if (desc->type == ISCSI_RX) {
812 				xfer_len = (unsigned long)wc.byte_len;
813 				iser_rcv_completion(desc, xfer_len);
814 			} else /* type == ISCSI_TX_CONTROL/SCSI_CMD/DOUT */
815 				iser_snd_completion(desc);
816 		} else {
817 			iser_err("comp w. error op %d status %d\n",desc->type,wc.status);
818 			iser_handle_comp_error(desc);
819 		}
820 	}
821 	/* #warning "it is assumed here that arming CQ only once its empty" *
822 	 * " would not cause interrupts to be missed"                       */
823 	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
824 }
825 
826 static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
827 {
828 	struct iser_device  *device = (struct iser_device *)cq_context;
829 
830 	tasklet_schedule(&device->cq_tasklet);
831 }
832