iser_verbs.c revision adfaa888a292e7f38fb43668d8994f246e371f0f
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
49static void iser_cq_tasklet_fn(unsigned long data);
50static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
51static void iser_comp_error_worker(void *data);
52
53static void iser_cq_event_callback(struct ib_event *cause, void *context)
54{
55	iser_err("got cq event %d \n", cause->event);
56}
57
58static 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 */
70static 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,
92				   IB_ACCESS_LOCAL_WRITE);
93	if (IS_ERR(device->mr))
94		goto dma_mr_err;
95
96	return 0;
97
98dma_mr_err:
99	tasklet_kill(&device->cq_tasklet);
100cq_arm_err:
101	ib_destroy_cq(device->cq);
102cq_err:
103	ib_dealloc_pd(device->pd);
104pd_err:
105	iser_err("failed to allocate an IB resource\n");
106	return -1;
107}
108
109/**
110 * iser_free_device_ib_res - destory/dealloc/dereg the DMA MR,
111 * CQ and PD created with the device associated with the adapator.
112 */
113static void iser_free_device_ib_res(struct iser_device *device)
114{
115	BUG_ON(device->mr == NULL);
116
117	tasklet_kill(&device->cq_tasklet);
118
119	(void)ib_dereg_mr(device->mr);
120	(void)ib_destroy_cq(device->cq);
121	(void)ib_dealloc_pd(device->pd);
122
123	device->mr = NULL;
124	device->cq = NULL;
125	device->pd = NULL;
126}
127
128/**
129 * iser_create_ib_conn_res - Creates FMR pool and Queue-Pair (QP)
130 *
131 * returns 0 on success, -1 on failure
132 */
133static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
134{
135	struct iser_device	*device;
136	struct ib_qp_init_attr	init_attr;
137	int			ret;
138	struct ib_fmr_pool_param params;
139
140	BUG_ON(ib_conn->device == NULL);
141
142	device = ib_conn->device;
143
144	ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
145				    (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
146				    GFP_KERNEL);
147	if (!ib_conn->page_vec) {
148		ret = -ENOMEM;
149		goto alloc_err;
150	}
151	ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
152
153	params.page_shift        = PAGE_SHIFT;
154	/* when the first/last SG element are not start/end *
155	 * page aligned, the map whould be of N+1 pages     */
156	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
157	/* make the pool size twice the max number of SCSI commands *
158	 * the ML is expected to queue, watermark for unmap at 50%  */
159	params.pool_size	 = ISCSI_XMIT_CMDS_MAX * 2;
160	params.dirty_watermark	 = ISCSI_XMIT_CMDS_MAX;
161	params.cache		 = 0;
162	params.flush_function	 = NULL;
163	params.access		 = (IB_ACCESS_LOCAL_WRITE  |
164				    IB_ACCESS_REMOTE_WRITE |
165				    IB_ACCESS_REMOTE_READ);
166
167	ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);
168	if (IS_ERR(ib_conn->fmr_pool)) {
169		ret = PTR_ERR(ib_conn->fmr_pool);
170		goto fmr_pool_err;
171	}
172
173	memset(&init_attr, 0, sizeof init_attr);
174
175	init_attr.event_handler = iser_qp_event_callback;
176	init_attr.qp_context	= (void *)ib_conn;
177	init_attr.send_cq	= device->cq;
178	init_attr.recv_cq	= device->cq;
179	init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS;
180	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
181	init_attr.cap.max_send_sge = MAX_REGD_BUF_VECTOR_LEN;
182	init_attr.cap.max_recv_sge = 2;
183	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;
184	init_attr.qp_type	= IB_QPT_RC;
185
186	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
187	if (ret)
188		goto qp_err;
189
190	ib_conn->qp = ib_conn->cma_id->qp;
191	iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",
192		 ib_conn, ib_conn->cma_id,
193		 ib_conn->fmr_pool, ib_conn->cma_id->qp);
194	return ret;
195
196qp_err:
197	(void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
198fmr_pool_err:
199	kfree(ib_conn->page_vec);
200alloc_err:
201	iser_err("unable to alloc mem or create resource, err %d\n", ret);
202	return ret;
203}
204
205/**
206 * releases the FMR pool, QP and CMA ID objects, returns 0 on success,
207 * -1 on failure
208 */
209static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
210{
211	BUG_ON(ib_conn == NULL);
212
213	iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",
214		 ib_conn, ib_conn->cma_id,
215		 ib_conn->fmr_pool, ib_conn->qp);
216
217	/* qp is created only once both addr & route are resolved */
218	if (ib_conn->fmr_pool != NULL)
219		ib_destroy_fmr_pool(ib_conn->fmr_pool);
220
221	if (ib_conn->qp != NULL)
222		rdma_destroy_qp(ib_conn->cma_id);
223
224	if (ib_conn->cma_id != NULL)
225		rdma_destroy_id(ib_conn->cma_id);
226
227	ib_conn->fmr_pool = NULL;
228	ib_conn->qp	  = NULL;
229	ib_conn->cma_id   = NULL;
230	kfree(ib_conn->page_vec);
231
232	return 0;
233}
234
235/**
236 * based on the resolved device node GUID see if there already allocated
237 * device for this device. If there's no such, create one.
238 */
239static
240struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
241{
242	struct list_head    *p_list;
243	struct iser_device  *device = NULL;
244
245	mutex_lock(&ig.device_list_mutex);
246
247	p_list = ig.device_list.next;
248	while (p_list != &ig.device_list) {
249		device = list_entry(p_list, struct iser_device, ig_list);
250		/* find if there's a match using the node GUID */
251		if (device->ib_device->node_guid == cma_id->device->node_guid)
252			break;
253	}
254
255	if (device == NULL) {
256		device = kzalloc(sizeof *device, GFP_KERNEL);
257		if (device == NULL)
258			goto out;
259		/* assign this device to the device */
260		device->ib_device = cma_id->device;
261		/* init the device and link it into ig device list */
262		if (iser_create_device_ib_res(device)) {
263			kfree(device);
264			device = NULL;
265			goto out;
266		}
267		list_add(&device->ig_list, &ig.device_list);
268	}
269out:
270	BUG_ON(device == NULL);
271	device->refcount++;
272	mutex_unlock(&ig.device_list_mutex);
273	return device;
274}
275
276/* if there's no demand for this device, release it */
277static void iser_device_try_release(struct iser_device *device)
278{
279	mutex_lock(&ig.device_list_mutex);
280	device->refcount--;
281	iser_err("device %p refcount %d\n",device,device->refcount);
282	if (!device->refcount) {
283		iser_free_device_ib_res(device);
284		list_del(&device->ig_list);
285		kfree(device);
286	}
287	mutex_unlock(&ig.device_list_mutex);
288}
289
290int iser_conn_state_comp(struct iser_conn *ib_conn,
291			enum iser_ib_conn_state comp)
292{
293	int ret;
294
295	spin_lock_bh(&ib_conn->lock);
296	ret = (ib_conn->state == comp);
297	spin_unlock_bh(&ib_conn->lock);
298	return ret;
299}
300
301static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
302				     enum iser_ib_conn_state comp,
303				     enum iser_ib_conn_state exch)
304{
305	int ret;
306
307	spin_lock_bh(&ib_conn->lock);
308	if ((ret = (ib_conn->state == comp)))
309		ib_conn->state = exch;
310	spin_unlock_bh(&ib_conn->lock);
311	return ret;
312}
313
314/**
315 * triggers start of the disconnect procedures and wait for them to be done
316 */
317void iser_conn_terminate(struct iser_conn *ib_conn)
318{
319	int err = 0;
320
321	/* change the ib conn state only if the conn is UP, however always call
322	 * rdma_disconnect since this is the only way to cause the CMA to change
323	 * the QP state to ERROR
324	 */
325
326	iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
327	err = rdma_disconnect(ib_conn->cma_id);
328	if (err)
329		iser_err("Failed to disconnect, conn: 0x%p err %d\n",
330			 ib_conn,err);
331
332	wait_event_interruptible(ib_conn->wait,
333				 ib_conn->state == ISER_CONN_DOWN);
334
335	iser_conn_release(ib_conn);
336}
337
338static void iser_connect_error(struct rdma_cm_id *cma_id)
339{
340	struct iser_conn *ib_conn;
341	ib_conn = (struct iser_conn *)cma_id->context;
342
343	ib_conn->state = ISER_CONN_DOWN;
344	wake_up_interruptible(&ib_conn->wait);
345}
346
347static void iser_addr_handler(struct rdma_cm_id *cma_id)
348{
349	struct iser_device *device;
350	struct iser_conn   *ib_conn;
351	int    ret;
352
353	device = iser_device_find_by_ib_device(cma_id);
354	ib_conn = (struct iser_conn *)cma_id->context;
355	ib_conn->device = device;
356
357	ret = rdma_resolve_route(cma_id, 1000);
358	if (ret) {
359		iser_err("resolve route failed: %d\n", ret);
360		iser_connect_error(cma_id);
361	}
362	return;
363}
364
365static void iser_route_handler(struct rdma_cm_id *cma_id)
366{
367	struct rdma_conn_param conn_param;
368	int    ret;
369
370	ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
371	if (ret)
372		goto failure;
373
374	iser_dbg("path.mtu is %d setting it to %d\n",
375		 cma_id->route.path_rec->mtu, IB_MTU_1024);
376
377	/* we must set the MTU to 1024 as this is what the target is assuming */
378	if (cma_id->route.path_rec->mtu > IB_MTU_1024)
379		cma_id->route.path_rec->mtu = IB_MTU_1024;
380
381	memset(&conn_param, 0, sizeof conn_param);
382	conn_param.responder_resources = 4;
383	conn_param.initiator_depth     = 1;
384	conn_param.retry_count	       = 7;
385	conn_param.rnr_retry_count     = 6;
386
387	ret = rdma_connect(cma_id, &conn_param);
388	if (ret) {
389		iser_err("failure connecting: %d\n", ret);
390		goto failure;
391	}
392
393	return;
394failure:
395	iser_connect_error(cma_id);
396}
397
398static void iser_connected_handler(struct rdma_cm_id *cma_id)
399{
400	struct iser_conn *ib_conn;
401
402	ib_conn = (struct iser_conn *)cma_id->context;
403	ib_conn->state = ISER_CONN_UP;
404	wake_up_interruptible(&ib_conn->wait);
405}
406
407static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
408{
409	struct iser_conn *ib_conn;
410
411	ib_conn = (struct iser_conn *)cma_id->context;
412	ib_conn->disc_evt_flag = 1;
413
414	/* getting here when the state is UP means that the conn is being *
415	 * terminated asynchronously from the iSCSI layer's perspective.  */
416	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
417				      ISER_CONN_TERMINATING))
418		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
419				   ISCSI_ERR_CONN_FAILED);
420
421	/* Complete the termination process if no posts are pending */
422	if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&
423	    (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
424		ib_conn->state = ISER_CONN_DOWN;
425		wake_up_interruptible(&ib_conn->wait);
426	}
427}
428
429static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
430{
431	int ret = 0;
432
433	iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);
434
435	switch (event->event) {
436	case RDMA_CM_EVENT_ADDR_RESOLVED:
437		iser_addr_handler(cma_id);
438		break;
439	case RDMA_CM_EVENT_ROUTE_RESOLVED:
440		iser_route_handler(cma_id);
441		break;
442	case RDMA_CM_EVENT_ESTABLISHED:
443		iser_connected_handler(cma_id);
444		break;
445	case RDMA_CM_EVENT_ADDR_ERROR:
446	case RDMA_CM_EVENT_ROUTE_ERROR:
447	case RDMA_CM_EVENT_CONNECT_ERROR:
448	case RDMA_CM_EVENT_UNREACHABLE:
449	case RDMA_CM_EVENT_REJECTED:
450		iser_err("event: %d, error: %d\n", event->event, event->status);
451		iser_connect_error(cma_id);
452		break;
453	case RDMA_CM_EVENT_DISCONNECTED:
454		iser_disconnected_handler(cma_id);
455		break;
456	case RDMA_CM_EVENT_DEVICE_REMOVAL:
457		BUG();
458		break;
459	case RDMA_CM_EVENT_CONNECT_RESPONSE:
460		BUG();
461		break;
462	case RDMA_CM_EVENT_CONNECT_REQUEST:
463	default:
464		break;
465	}
466	return ret;
467}
468
469int iser_conn_init(struct iser_conn **ibconn)
470{
471	struct iser_conn *ib_conn;
472
473	ib_conn = kzalloc(sizeof *ib_conn, GFP_KERNEL);
474	if (!ib_conn) {
475		iser_err("can't alloc memory for struct iser_conn\n");
476		return -ENOMEM;
477	}
478	ib_conn->state = ISER_CONN_INIT;
479	init_waitqueue_head(&ib_conn->wait);
480	atomic_set(&ib_conn->post_recv_buf_count, 0);
481	atomic_set(&ib_conn->post_send_buf_count, 0);
482	INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker,
483		  ib_conn);
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 */
495int 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
546id_failure:
547	ib_conn->cma_id = NULL;
548addr_failure:
549	ib_conn->state = ISER_CONN_DOWN;
550connect_failure:
551	iser_conn_release(ib_conn);
552	return err;
553}
554
555/**
556 * Frees all conn objects and deallocs conn descriptor
557 */
558void 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	kfree(ib_conn);
574}
575
576
577/**
578 * iser_reg_page_vec - Register physical memory
579 *
580 * returns: 0 on success, errno code on failure
581 */
582int iser_reg_page_vec(struct iser_conn     *ib_conn,
583		      struct iser_page_vec *page_vec,
584		      struct iser_mem_reg  *mem_reg)
585{
586	struct ib_pool_fmr *mem;
587	u64		   io_addr;
588	u64		   *page_list;
589	int		   status;
590
591	page_list = page_vec->pages;
592	io_addr	  = page_list[0];
593
594	mem  = ib_fmr_pool_map_phys(ib_conn->fmr_pool,
595				    page_list,
596				    page_vec->length,
597				    io_addr);
598
599	if (IS_ERR(mem)) {
600		status = (int)PTR_ERR(mem);
601		iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
602		return status;
603	}
604
605	mem_reg->lkey  = mem->fmr->lkey;
606	mem_reg->rkey  = mem->fmr->rkey;
607	mem_reg->len   = page_vec->length * PAGE_SIZE;
608	mem_reg->va    = io_addr;
609	mem_reg->mem_h = (void *)mem;
610
611	mem_reg->va   += page_vec->offset;
612	mem_reg->len   = page_vec->data_size;
613
614	iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
615		 "entry[0]: (0x%08lx,%ld)] -> "
616		 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
617		 page_vec, page_vec->length,
618		 (unsigned long)page_vec->pages[0],
619		 (unsigned long)page_vec->data_size,
620		 (unsigned int)mem_reg->lkey, mem_reg->mem_h,
621		 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
622	return 0;
623}
624
625/**
626 * Unregister (previosuly registered) memory.
627 */
628void iser_unreg_mem(struct iser_mem_reg *reg)
629{
630	int ret;
631
632	iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
633
634	ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
635	if (ret)
636		iser_err("ib_fmr_pool_unmap failed %d\n", ret);
637
638	reg->mem_h = NULL;
639}
640
641/**
642 * iser_dto_to_iov - builds IOV from a dto descriptor
643 */
644static void iser_dto_to_iov(struct iser_dto *dto, struct ib_sge *iov, int iov_len)
645{
646	int		     i;
647	struct ib_sge	     *sge;
648	struct iser_regd_buf *regd_buf;
649
650	if (dto->regd_vector_len > iov_len) {
651		iser_err("iov size %d too small for posting dto of len %d\n",
652			 iov_len, dto->regd_vector_len);
653		BUG();
654	}
655
656	for (i = 0; i < dto->regd_vector_len; i++) {
657		sge	    = &iov[i];
658		regd_buf  = dto->regd[i];
659
660		sge->addr   = regd_buf->reg.va;
661		sge->length = regd_buf->reg.len;
662		sge->lkey   = regd_buf->reg.lkey;
663
664		if (dto->used_sz[i] > 0)  /* Adjust size */
665			sge->length = dto->used_sz[i];
666
667		/* offset and length should not exceed the regd buf length */
668		if (sge->length + dto->offset[i] > regd_buf->reg.len) {
669			iser_err("Used len:%ld + offset:%d, exceed reg.buf.len:"
670				 "%ld in dto:0x%p [%d], va:0x%08lX\n",
671				 (unsigned long)sge->length, dto->offset[i],
672				 (unsigned long)regd_buf->reg.len, dto, i,
673				 (unsigned long)sge->addr);
674			BUG();
675		}
676
677		sge->addr += dto->offset[i]; /* Adjust offset */
678	}
679}
680
681/**
682 * iser_post_recv - Posts a receive buffer.
683 *
684 * returns 0 on success, -1 on failure
685 */
686int iser_post_recv(struct iser_desc *rx_desc)
687{
688	int		  ib_ret, ret_val = 0;
689	struct ib_recv_wr recv_wr, *recv_wr_failed;
690	struct ib_sge	  iov[2];
691	struct iser_conn  *ib_conn;
692	struct iser_dto   *recv_dto = &rx_desc->dto;
693
694	/* Retrieve conn */
695	ib_conn = recv_dto->conn->ib_conn;
696
697	iser_dto_to_iov(recv_dto, iov, 2);
698
699	recv_wr.next	= NULL;
700	recv_wr.sg_list = iov;
701	recv_wr.num_sge = recv_dto->regd_vector_len;
702	recv_wr.wr_id	= (unsigned long)rx_desc;
703
704	atomic_inc(&ib_conn->post_recv_buf_count);
705	ib_ret	= ib_post_recv(ib_conn->qp, &recv_wr, &recv_wr_failed);
706	if (ib_ret) {
707		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
708		atomic_dec(&ib_conn->post_recv_buf_count);
709		ret_val = -1;
710	}
711
712	return ret_val;
713}
714
715/**
716 * iser_start_send - Initiate a Send DTO operation
717 *
718 * returns 0 on success, -1 on failure
719 */
720int iser_post_send(struct iser_desc *tx_desc)
721{
722	int		  ib_ret, ret_val = 0;
723	struct ib_send_wr send_wr, *send_wr_failed;
724	struct ib_sge	  iov[MAX_REGD_BUF_VECTOR_LEN];
725	struct iser_conn  *ib_conn;
726	struct iser_dto   *dto = &tx_desc->dto;
727
728	ib_conn = dto->conn->ib_conn;
729
730	iser_dto_to_iov(dto, iov, MAX_REGD_BUF_VECTOR_LEN);
731
732	send_wr.next	   = NULL;
733	send_wr.wr_id	   = (unsigned long)tx_desc;
734	send_wr.sg_list	   = iov;
735	send_wr.num_sge	   = dto->regd_vector_len;
736	send_wr.opcode	   = IB_WR_SEND;
737	send_wr.send_flags = dto->notify_enable ? IB_SEND_SIGNALED : 0;
738
739	atomic_inc(&ib_conn->post_send_buf_count);
740
741	ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
742	if (ib_ret) {
743		iser_err("Failed to start SEND DTO, dto: 0x%p, IOV len: %d\n",
744			 dto, dto->regd_vector_len);
745		iser_err("ib_post_send failed, ret:%d\n", ib_ret);
746		atomic_dec(&ib_conn->post_send_buf_count);
747		ret_val = -1;
748	}
749
750	return ret_val;
751}
752
753static void iser_comp_error_worker(void *data)
754{
755	struct iser_conn *ib_conn = data;
756
757	/* getting here when the state is UP means that the conn is being *
758	 * terminated asynchronously from the iSCSI layer's perspective.  */
759	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
760				      ISER_CONN_TERMINATING))
761		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
762					ISCSI_ERR_CONN_FAILED);
763
764	/* complete the termination process if disconnect event was delivered *
765	 * note there are no more non completed posts to the QP               */
766	if (ib_conn->disc_evt_flag) {
767		ib_conn->state = ISER_CONN_DOWN;
768		wake_up_interruptible(&ib_conn->wait);
769	}
770}
771
772static void iser_handle_comp_error(struct iser_desc *desc)
773{
774	struct iser_dto  *dto     = &desc->dto;
775	struct iser_conn *ib_conn = dto->conn->ib_conn;
776
777	iser_dto_buffs_release(dto);
778
779	if (desc->type == ISCSI_RX) {
780		kfree(desc->data);
781		kmem_cache_free(ig.desc_cache, desc);
782		atomic_dec(&ib_conn->post_recv_buf_count);
783	} else { /* type is TX control/command/dataout */
784		if (desc->type == ISCSI_TX_DATAOUT)
785			kmem_cache_free(ig.desc_cache, desc);
786		atomic_dec(&ib_conn->post_send_buf_count);
787	}
788
789	if (atomic_read(&ib_conn->post_recv_buf_count) == 0 &&
790	    atomic_read(&ib_conn->post_send_buf_count) == 0)
791		schedule_work(&ib_conn->comperror_work);
792}
793
794static void iser_cq_tasklet_fn(unsigned long data)
795{
796	 struct iser_device  *device = (struct iser_device *)data;
797	 struct ib_cq	     *cq = device->cq;
798	 struct ib_wc	     wc;
799	 struct iser_desc    *desc;
800	 unsigned long	     xfer_len;
801
802	while (ib_poll_cq(cq, 1, &wc) == 1) {
803		desc	 = (struct iser_desc *) (unsigned long) wc.wr_id;
804		BUG_ON(desc == NULL);
805
806		if (wc.status == IB_WC_SUCCESS) {
807			if (desc->type == ISCSI_RX) {
808				xfer_len = (unsigned long)wc.byte_len;
809				iser_rcv_completion(desc, xfer_len);
810			} else /* type == ISCSI_TX_CONTROL/SCSI_CMD/DOUT */
811				iser_snd_completion(desc);
812		} else {
813			iser_err("comp w. error op %d status %d\n",desc->type,wc.status);
814			iser_handle_comp_error(desc);
815		}
816	}
817	/* #warning "it is assumed here that arming CQ only once its empty" *
818	 * " would not cause interrupts to be missed"                       */
819	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
820}
821
822static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
823{
824	struct iser_device  *device = (struct iser_device *)cq_context;
825
826	tasklet_schedule(&device->cq_tasklet);
827}
828