iser_verbs.c revision aae3c995ff74a183d15207436d383942485b2edd
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#include <linux/kernel.h>
34#include <linux/module.h>
35#include <linux/delay.h>
36
37#include "iscsi_iser.h"
38
39#define ISCSI_ISER_MAX_CONN	8
40#define ISER_MAX_RX_CQ_LEN	(ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
41#define ISER_MAX_TX_CQ_LEN	(ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)
42
43static void iser_cq_tasklet_fn(unsigned long data);
44static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
45
46static void iser_cq_event_callback(struct ib_event *cause, void *context)
47{
48	iser_err("got cq event %d \n", cause->event);
49}
50
51static void iser_qp_event_callback(struct ib_event *cause, void *context)
52{
53	iser_err("got qp event %d\n",cause->event);
54}
55
56/**
57 * iser_create_device_ib_res - creates Protection Domain (PD), Completion
58 * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
59 * the adapator.
60 *
61 * returns 0 on success, -1 on failure
62 */
63static int iser_create_device_ib_res(struct iser_device *device)
64{
65	device->pd = ib_alloc_pd(device->ib_device);
66	if (IS_ERR(device->pd))
67		goto pd_err;
68
69	device->rx_cq = ib_create_cq(device->ib_device,
70				  iser_cq_callback,
71				  iser_cq_event_callback,
72				  (void *)device,
73				  ISER_MAX_RX_CQ_LEN, 0);
74	if (IS_ERR(device->rx_cq))
75		goto rx_cq_err;
76
77	device->tx_cq = ib_create_cq(device->ib_device,
78				  NULL, iser_cq_event_callback,
79				  (void *)device,
80				  ISER_MAX_TX_CQ_LEN, 0);
81
82	if (IS_ERR(device->tx_cq))
83		goto tx_cq_err;
84
85	if (ib_req_notify_cq(device->rx_cq, IB_CQ_NEXT_COMP))
86		goto cq_arm_err;
87
88	tasklet_init(&device->cq_tasklet,
89		     iser_cq_tasklet_fn,
90		     (unsigned long)device);
91
92	device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
93				   IB_ACCESS_REMOTE_WRITE |
94				   IB_ACCESS_REMOTE_READ);
95	if (IS_ERR(device->mr))
96		goto dma_mr_err;
97
98	return 0;
99
100dma_mr_err:
101	tasklet_kill(&device->cq_tasklet);
102cq_arm_err:
103	ib_destroy_cq(device->tx_cq);
104tx_cq_err:
105	ib_destroy_cq(device->rx_cq);
106rx_cq_err:
107	ib_dealloc_pd(device->pd);
108pd_err:
109	iser_err("failed to allocate an IB resource\n");
110	return -1;
111}
112
113/**
114 * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
115 * CQ and PD created with the device associated with the adapator.
116 */
117static void iser_free_device_ib_res(struct iser_device *device)
118{
119	BUG_ON(device->mr == NULL);
120
121	tasklet_kill(&device->cq_tasklet);
122
123	(void)ib_dereg_mr(device->mr);
124	(void)ib_destroy_cq(device->tx_cq);
125	(void)ib_destroy_cq(device->rx_cq);
126	(void)ib_dealloc_pd(device->pd);
127
128	device->mr = NULL;
129	device->tx_cq = NULL;
130	device->rx_cq = NULL;
131	device->pd = NULL;
132}
133
134/**
135 * iser_create_ib_conn_res - Creates FMR pool and Queue-Pair (QP)
136 *
137 * returns 0 on success, -1 on failure
138 */
139static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
140{
141	struct iser_device	*device;
142	struct ib_qp_init_attr	init_attr;
143	int			ret = -ENOMEM;
144	struct ib_fmr_pool_param params;
145
146	BUG_ON(ib_conn->device == NULL);
147
148	device = ib_conn->device;
149
150	ib_conn->login_buf = kmalloc(ISER_RX_LOGIN_SIZE, GFP_KERNEL);
151	if (!ib_conn->login_buf) {
152		goto alloc_err;
153		ret = -ENOMEM;
154	}
155
156	ib_conn->login_dma = ib_dma_map_single(ib_conn->device->ib_device,
157				(void *)ib_conn->login_buf, ISER_RX_LOGIN_SIZE,
158				DMA_FROM_DEVICE);
159
160	ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
161				    (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
162				    GFP_KERNEL);
163	if (!ib_conn->page_vec) {
164		ret = -ENOMEM;
165		goto alloc_err;
166	}
167	ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
168
169	params.page_shift        = SHIFT_4K;
170	/* when the first/last SG element are not start/end *
171	 * page aligned, the map whould be of N+1 pages     */
172	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
173	/* make the pool size twice the max number of SCSI commands *
174	 * the ML is expected to queue, watermark for unmap at 50%  */
175	params.pool_size	 = ISCSI_DEF_XMIT_CMDS_MAX * 2;
176	params.dirty_watermark	 = ISCSI_DEF_XMIT_CMDS_MAX;
177	params.cache		 = 0;
178	params.flush_function	 = NULL;
179	params.access		 = (IB_ACCESS_LOCAL_WRITE  |
180				    IB_ACCESS_REMOTE_WRITE |
181				    IB_ACCESS_REMOTE_READ);
182
183	ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);
184	if (IS_ERR(ib_conn->fmr_pool)) {
185		ret = PTR_ERR(ib_conn->fmr_pool);
186		goto fmr_pool_err;
187	}
188
189	memset(&init_attr, 0, sizeof init_attr);
190
191	init_attr.event_handler = iser_qp_event_callback;
192	init_attr.qp_context	= (void *)ib_conn;
193	init_attr.send_cq	= device->tx_cq;
194	init_attr.recv_cq	= device->rx_cq;
195	init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS;
196	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
197	init_attr.cap.max_send_sge = 2;
198	init_attr.cap.max_recv_sge = 1;
199	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;
200	init_attr.qp_type	= IB_QPT_RC;
201
202	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
203	if (ret)
204		goto qp_err;
205
206	ib_conn->qp = ib_conn->cma_id->qp;
207	iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",
208		 ib_conn, ib_conn->cma_id,
209		 ib_conn->fmr_pool, ib_conn->cma_id->qp);
210	return ret;
211
212qp_err:
213	(void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
214fmr_pool_err:
215	kfree(ib_conn->page_vec);
216	kfree(ib_conn->login_buf);
217alloc_err:
218	iser_err("unable to alloc mem or create resource, err %d\n", ret);
219	return ret;
220}
221
222/**
223 * releases the FMR pool, QP and CMA ID objects, returns 0 on success,
224 * -1 on failure
225 */
226static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
227{
228	BUG_ON(ib_conn == NULL);
229
230	iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",
231		 ib_conn, ib_conn->cma_id,
232		 ib_conn->fmr_pool, ib_conn->qp);
233
234	/* qp is created only once both addr & route are resolved */
235	if (ib_conn->fmr_pool != NULL)
236		ib_destroy_fmr_pool(ib_conn->fmr_pool);
237
238	if (ib_conn->qp != NULL)
239		rdma_destroy_qp(ib_conn->cma_id);
240
241	if (ib_conn->cma_id != NULL)
242		rdma_destroy_id(ib_conn->cma_id);
243
244	ib_conn->fmr_pool = NULL;
245	ib_conn->qp	  = NULL;
246	ib_conn->cma_id   = NULL;
247	kfree(ib_conn->page_vec);
248
249	return 0;
250}
251
252/**
253 * based on the resolved device node GUID see if there already allocated
254 * device for this device. If there's no such, create one.
255 */
256static
257struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
258{
259	struct iser_device *device;
260
261	mutex_lock(&ig.device_list_mutex);
262
263	list_for_each_entry(device, &ig.device_list, ig_list)
264		/* find if there's a match using the node GUID */
265		if (device->ib_device->node_guid == cma_id->device->node_guid)
266			goto inc_refcnt;
267
268	device = kzalloc(sizeof *device, GFP_KERNEL);
269	if (device == NULL)
270		goto out;
271
272	/* assign this device to the device */
273	device->ib_device = cma_id->device;
274	/* init the device and link it into ig device list */
275	if (iser_create_device_ib_res(device)) {
276		kfree(device);
277		device = NULL;
278		goto out;
279	}
280	list_add(&device->ig_list, &ig.device_list);
281
282inc_refcnt:
283	device->refcount++;
284out:
285	mutex_unlock(&ig.device_list_mutex);
286	return device;
287}
288
289/* if there's no demand for this device, release it */
290static void iser_device_try_release(struct iser_device *device)
291{
292	mutex_lock(&ig.device_list_mutex);
293	device->refcount--;
294	iser_err("device %p refcount %d\n",device,device->refcount);
295	if (!device->refcount) {
296		iser_free_device_ib_res(device);
297		list_del(&device->ig_list);
298		kfree(device);
299	}
300	mutex_unlock(&ig.device_list_mutex);
301}
302
303static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
304				     enum iser_ib_conn_state comp,
305				     enum iser_ib_conn_state exch)
306{
307	int ret;
308
309	spin_lock_bh(&ib_conn->lock);
310	if ((ret = (ib_conn->state == comp)))
311		ib_conn->state = exch;
312	spin_unlock_bh(&ib_conn->lock);
313	return ret;
314}
315
316/**
317 * Frees all conn objects and deallocs conn descriptor
318 */
319static void iser_conn_release(struct iser_conn *ib_conn)
320{
321	struct iser_device  *device = ib_conn->device;
322
323	BUG_ON(ib_conn->state != ISER_CONN_DOWN);
324
325	mutex_lock(&ig.connlist_mutex);
326	list_del(&ib_conn->conn_list);
327	mutex_unlock(&ig.connlist_mutex);
328	iser_free_rx_descriptors(ib_conn);
329	iser_free_ib_conn_res(ib_conn);
330	ib_conn->device = NULL;
331	/* on EVENT_ADDR_ERROR there's no device yet for this conn */
332	if (device != NULL)
333		iser_device_try_release(device);
334	if (ib_conn->iser_conn)
335		ib_conn->iser_conn->ib_conn = NULL;
336	iscsi_destroy_endpoint(ib_conn->ep);
337}
338
339void iser_conn_get(struct iser_conn *ib_conn)
340{
341	atomic_inc(&ib_conn->refcount);
342}
343
344void iser_conn_put(struct iser_conn *ib_conn)
345{
346	if (atomic_dec_and_test(&ib_conn->refcount))
347		iser_conn_release(ib_conn);
348}
349
350/**
351 * triggers start of the disconnect procedures and wait for them to be done
352 */
353void iser_conn_terminate(struct iser_conn *ib_conn)
354{
355	int err = 0;
356
357	/* change the ib conn state only if the conn is UP, however always call
358	 * rdma_disconnect since this is the only way to cause the CMA to change
359	 * the QP state to ERROR
360	 */
361
362	iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
363	err = rdma_disconnect(ib_conn->cma_id);
364	if (err)
365		iser_err("Failed to disconnect, conn: 0x%p err %d\n",
366			 ib_conn,err);
367
368	wait_event_interruptible(ib_conn->wait,
369				 ib_conn->state == ISER_CONN_DOWN);
370
371	iser_conn_put(ib_conn);
372}
373
374static void iser_connect_error(struct rdma_cm_id *cma_id)
375{
376	struct iser_conn *ib_conn;
377	ib_conn = (struct iser_conn *)cma_id->context;
378
379	ib_conn->state = ISER_CONN_DOWN;
380	wake_up_interruptible(&ib_conn->wait);
381}
382
383static void iser_addr_handler(struct rdma_cm_id *cma_id)
384{
385	struct iser_device *device;
386	struct iser_conn   *ib_conn;
387	int    ret;
388
389	device = iser_device_find_by_ib_device(cma_id);
390	if (!device) {
391		iser_err("device lookup/creation failed\n");
392		iser_connect_error(cma_id);
393		return;
394	}
395
396	ib_conn = (struct iser_conn *)cma_id->context;
397	ib_conn->device = device;
398
399	ret = rdma_resolve_route(cma_id, 1000);
400	if (ret) {
401		iser_err("resolve route failed: %d\n", ret);
402		iser_connect_error(cma_id);
403	}
404}
405
406static void iser_route_handler(struct rdma_cm_id *cma_id)
407{
408	struct rdma_conn_param conn_param;
409	int    ret;
410
411	ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
412	if (ret)
413		goto failure;
414
415	memset(&conn_param, 0, sizeof conn_param);
416	conn_param.responder_resources = 4;
417	conn_param.initiator_depth     = 1;
418	conn_param.retry_count	       = 7;
419	conn_param.rnr_retry_count     = 6;
420
421	ret = rdma_connect(cma_id, &conn_param);
422	if (ret) {
423		iser_err("failure connecting: %d\n", ret);
424		goto failure;
425	}
426
427	return;
428failure:
429	iser_connect_error(cma_id);
430}
431
432static void iser_connected_handler(struct rdma_cm_id *cma_id)
433{
434	struct iser_conn *ib_conn;
435
436	ib_conn = (struct iser_conn *)cma_id->context;
437	ib_conn->state = ISER_CONN_UP;
438	wake_up_interruptible(&ib_conn->wait);
439}
440
441static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
442{
443	struct iser_conn *ib_conn;
444
445	ib_conn = (struct iser_conn *)cma_id->context;
446	ib_conn->disc_evt_flag = 1;
447
448	/* getting here when the state is UP means that the conn is being *
449	 * terminated asynchronously from the iSCSI layer's perspective.  */
450	if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
451				      ISER_CONN_TERMINATING))
452		iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
453				   ISCSI_ERR_CONN_FAILED);
454
455	/* Complete the termination process if no posts are pending */
456	if (ib_conn->post_recv_buf_count == 0 &&
457	    (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
458		ib_conn->state = ISER_CONN_DOWN;
459		wake_up_interruptible(&ib_conn->wait);
460	}
461}
462
463static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
464{
465	int ret = 0;
466
467	iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);
468
469	switch (event->event) {
470	case RDMA_CM_EVENT_ADDR_RESOLVED:
471		iser_addr_handler(cma_id);
472		break;
473	case RDMA_CM_EVENT_ROUTE_RESOLVED:
474		iser_route_handler(cma_id);
475		break;
476	case RDMA_CM_EVENT_ESTABLISHED:
477		iser_connected_handler(cma_id);
478		break;
479	case RDMA_CM_EVENT_ADDR_ERROR:
480	case RDMA_CM_EVENT_ROUTE_ERROR:
481	case RDMA_CM_EVENT_CONNECT_ERROR:
482	case RDMA_CM_EVENT_UNREACHABLE:
483	case RDMA_CM_EVENT_REJECTED:
484		iser_err("event: %d, error: %d\n", event->event, event->status);
485		iser_connect_error(cma_id);
486		break;
487	case RDMA_CM_EVENT_DISCONNECTED:
488	case RDMA_CM_EVENT_DEVICE_REMOVAL:
489	case RDMA_CM_EVENT_ADDR_CHANGE:
490		iser_disconnected_handler(cma_id);
491		break;
492	default:
493		iser_err("Unexpected RDMA CM event (%d)\n", event->event);
494		break;
495	}
496	return ret;
497}
498
499void iser_conn_init(struct iser_conn *ib_conn)
500{
501	ib_conn->state = ISER_CONN_INIT;
502	init_waitqueue_head(&ib_conn->wait);
503	ib_conn->post_recv_buf_count = 0;
504	atomic_set(&ib_conn->post_send_buf_count, 0);
505	atomic_set(&ib_conn->refcount, 1);
506	INIT_LIST_HEAD(&ib_conn->conn_list);
507	spin_lock_init(&ib_conn->lock);
508}
509
510 /**
511 * starts the process of connecting to the target
512 * sleeps until the connection is established or rejected
513 */
514int iser_connect(struct iser_conn   *ib_conn,
515		 struct sockaddr_in *src_addr,
516		 struct sockaddr_in *dst_addr,
517		 int                 non_blocking)
518{
519	struct sockaddr *src, *dst;
520	int err = 0;
521
522	sprintf(ib_conn->name, "%pI4:%d",
523		&dst_addr->sin_addr.s_addr, dst_addr->sin_port);
524
525	/* the device is known only --after-- address resolution */
526	ib_conn->device = NULL;
527
528	iser_err("connecting to: %pI4, port 0x%x\n",
529		 &dst_addr->sin_addr, dst_addr->sin_port);
530
531	ib_conn->state = ISER_CONN_PENDING;
532
533	ib_conn->cma_id = rdma_create_id(iser_cma_handler,
534					     (void *)ib_conn,
535					     RDMA_PS_TCP);
536	if (IS_ERR(ib_conn->cma_id)) {
537		err = PTR_ERR(ib_conn->cma_id);
538		iser_err("rdma_create_id failed: %d\n", err);
539		goto id_failure;
540	}
541
542	src = (struct sockaddr *)src_addr;
543	dst = (struct sockaddr *)dst_addr;
544	err = rdma_resolve_addr(ib_conn->cma_id, src, dst, 1000);
545	if (err) {
546		iser_err("rdma_resolve_addr failed: %d\n", err);
547		goto addr_failure;
548	}
549
550	if (!non_blocking) {
551		wait_event_interruptible(ib_conn->wait,
552					 (ib_conn->state != ISER_CONN_PENDING));
553
554		if (ib_conn->state != ISER_CONN_UP) {
555			err =  -EIO;
556			goto connect_failure;
557		}
558	}
559
560	mutex_lock(&ig.connlist_mutex);
561	list_add(&ib_conn->conn_list, &ig.connlist);
562	mutex_unlock(&ig.connlist_mutex);
563	return 0;
564
565id_failure:
566	ib_conn->cma_id = NULL;
567addr_failure:
568	ib_conn->state = ISER_CONN_DOWN;
569connect_failure:
570	iser_conn_release(ib_conn);
571	return err;
572}
573
574/**
575 * iser_reg_page_vec - Register physical memory
576 *
577 * returns: 0 on success, errno code on failure
578 */
579int iser_reg_page_vec(struct iser_conn     *ib_conn,
580		      struct iser_page_vec *page_vec,
581		      struct iser_mem_reg  *mem_reg)
582{
583	struct ib_pool_fmr *mem;
584	u64		   io_addr;
585	u64		   *page_list;
586	int		   status;
587
588	page_list = page_vec->pages;
589	io_addr	  = page_list[0];
590
591	mem  = ib_fmr_pool_map_phys(ib_conn->fmr_pool,
592				    page_list,
593				    page_vec->length,
594				    io_addr);
595
596	if (IS_ERR(mem)) {
597		status = (int)PTR_ERR(mem);
598		iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
599		return status;
600	}
601
602	mem_reg->lkey  = mem->fmr->lkey;
603	mem_reg->rkey  = mem->fmr->rkey;
604	mem_reg->len   = page_vec->length * SIZE_4K;
605	mem_reg->va    = io_addr;
606	mem_reg->is_fmr = 1;
607	mem_reg->mem_h = (void *)mem;
608
609	mem_reg->va   += page_vec->offset;
610	mem_reg->len   = page_vec->data_size;
611
612	iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
613		 "entry[0]: (0x%08lx,%ld)] -> "
614		 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
615		 page_vec, page_vec->length,
616		 (unsigned long)page_vec->pages[0],
617		 (unsigned long)page_vec->data_size,
618		 (unsigned int)mem_reg->lkey, mem_reg->mem_h,
619		 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
620	return 0;
621}
622
623/**
624 * Unregister (previosuly registered) memory.
625 */
626void iser_unreg_mem(struct iser_mem_reg *reg)
627{
628	int ret;
629
630	iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
631
632	ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
633	if (ret)
634		iser_err("ib_fmr_pool_unmap failed %d\n", ret);
635
636	reg->mem_h = NULL;
637}
638
639int iser_post_recvl(struct iser_conn *ib_conn)
640{
641	struct ib_recv_wr rx_wr, *rx_wr_failed;
642	struct ib_sge	  sge;
643	int ib_ret;
644
645	sge.addr   = ib_conn->login_dma;
646	sge.length = ISER_RX_LOGIN_SIZE;
647	sge.lkey   = ib_conn->device->mr->lkey;
648
649	rx_wr.wr_id   = (unsigned long)ib_conn->login_buf;
650	rx_wr.sg_list = &sge;
651	rx_wr.num_sge = 1;
652	rx_wr.next    = NULL;
653
654	ib_conn->post_recv_buf_count++;
655	ib_ret	= ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
656	if (ib_ret) {
657		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
658		ib_conn->post_recv_buf_count--;
659	}
660	return ib_ret;
661}
662
663int iser_post_recvm(struct iser_conn *ib_conn, int count)
664{
665	struct ib_recv_wr *rx_wr, *rx_wr_failed;
666	int i, ib_ret;
667	unsigned int my_rx_head = ib_conn->rx_desc_head;
668	struct iser_rx_desc *rx_desc;
669
670	for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
671		rx_desc		= &ib_conn->rx_descs[my_rx_head];
672		rx_wr->wr_id	= (unsigned long)rx_desc;
673		rx_wr->sg_list	= &rx_desc->rx_sg;
674		rx_wr->num_sge	= 1;
675		rx_wr->next	= rx_wr + 1;
676		my_rx_head = (my_rx_head + 1) & (ISER_QP_MAX_RECV_DTOS - 1);
677	}
678
679	rx_wr--;
680	rx_wr->next = NULL; /* mark end of work requests list */
681
682	ib_conn->post_recv_buf_count += count;
683	ib_ret	= ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
684	if (ib_ret) {
685		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
686		ib_conn->post_recv_buf_count -= count;
687	} else
688		ib_conn->rx_desc_head = my_rx_head;
689	return ib_ret;
690}
691
692
693/**
694 * iser_start_send - Initiate a Send DTO operation
695 *
696 * returns 0 on success, -1 on failure
697 */
698int iser_post_send(struct iser_conn *ib_conn, struct iser_tx_desc *tx_desc)
699{
700	int		  ib_ret;
701	struct ib_send_wr send_wr, *send_wr_failed;
702
703	ib_dma_sync_single_for_device(ib_conn->device->ib_device,
704		tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);
705
706	send_wr.next	   = NULL;
707	send_wr.wr_id	   = (unsigned long)tx_desc;
708	send_wr.sg_list	   = tx_desc->tx_sg;
709	send_wr.num_sge	   = tx_desc->num_sge;
710	send_wr.opcode	   = IB_WR_SEND;
711	send_wr.send_flags = IB_SEND_SIGNALED;
712
713	atomic_inc(&ib_conn->post_send_buf_count);
714
715	ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
716	if (ib_ret) {
717		iser_err("ib_post_send failed, ret:%d\n", ib_ret);
718		atomic_dec(&ib_conn->post_send_buf_count);
719	}
720	return ib_ret;
721}
722
723static void iser_handle_comp_error(struct iser_tx_desc *desc,
724				struct iser_conn *ib_conn)
725{
726	if (desc && desc->type == ISCSI_TX_DATAOUT)
727		kmem_cache_free(ig.desc_cache, desc);
728
729	if (ib_conn->post_recv_buf_count == 0 &&
730	    atomic_read(&ib_conn->post_send_buf_count) == 0) {
731		/* getting here when the state is UP means that the conn is *
732		 * being terminated asynchronously from the iSCSI layer's   *
733		 * perspective.                                             */
734		if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
735		    ISER_CONN_TERMINATING))
736			iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
737					   ISCSI_ERR_CONN_FAILED);
738
739		/* complete the termination process if disconnect event was delivered *
740		 * note there are no more non completed posts to the QP               */
741		if (ib_conn->disc_evt_flag) {
742			ib_conn->state = ISER_CONN_DOWN;
743			wake_up_interruptible(&ib_conn->wait);
744		}
745	}
746}
747
748static int iser_drain_tx_cq(struct iser_device  *device)
749{
750	struct ib_cq  *cq = device->tx_cq;
751	struct ib_wc  wc;
752	struct iser_tx_desc *tx_desc;
753	struct iser_conn *ib_conn;
754	int completed_tx = 0;
755
756	while (ib_poll_cq(cq, 1, &wc) == 1) {
757		tx_desc	= (struct iser_tx_desc *) (unsigned long) wc.wr_id;
758		ib_conn = wc.qp->qp_context;
759		if (wc.status == IB_WC_SUCCESS) {
760			if (wc.opcode == IB_WC_SEND)
761				iser_snd_completion(tx_desc, ib_conn);
762			else
763				iser_err("expected opcode %d got %d\n",
764					IB_WC_SEND, wc.opcode);
765		} else {
766			iser_err("tx id %llx status %d vend_err %x\n",
767				wc.wr_id, wc.status, wc.vendor_err);
768			atomic_dec(&ib_conn->post_send_buf_count);
769			iser_handle_comp_error(tx_desc, ib_conn);
770		}
771		completed_tx++;
772	}
773	return completed_tx;
774}
775
776
777static void iser_cq_tasklet_fn(unsigned long data)
778{
779	 struct iser_device  *device = (struct iser_device *)data;
780	 struct ib_cq	     *cq = device->rx_cq;
781	 struct ib_wc	     wc;
782	 struct iser_rx_desc *desc;
783	 unsigned long	     xfer_len;
784	struct iser_conn *ib_conn;
785	int completed_tx, completed_rx;
786	completed_tx = completed_rx = 0;
787
788	while (ib_poll_cq(cq, 1, &wc) == 1) {
789		desc	 = (struct iser_rx_desc *) (unsigned long) wc.wr_id;
790		BUG_ON(desc == NULL);
791		ib_conn = wc.qp->qp_context;
792		if (wc.status == IB_WC_SUCCESS) {
793			if (wc.opcode == IB_WC_RECV) {
794				xfer_len = (unsigned long)wc.byte_len;
795				iser_rcv_completion(desc, xfer_len, ib_conn);
796			} else
797				iser_err("expected opcode %d got %d\n",
798					IB_WC_RECV, wc.opcode);
799		} else {
800			if (wc.status != IB_WC_WR_FLUSH_ERR)
801				iser_err("rx id %llx status %d vend_err %x\n",
802					wc.wr_id, wc.status, wc.vendor_err);
803			ib_conn->post_recv_buf_count--;
804			iser_handle_comp_error(NULL, ib_conn);
805		}
806		completed_rx++;
807		if (!(completed_rx & 63))
808			completed_tx += iser_drain_tx_cq(device);
809	}
810	/* #warning "it is assumed here that arming CQ only once its empty" *
811	 * " would not cause interrupts to be missed"                       */
812	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
813
814	completed_tx += iser_drain_tx_cq(device);
815	iser_dbg("got %d rx %d tx completions\n", completed_rx, completed_tx);
816}
817
818static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
819{
820	struct iser_device  *device = (struct iser_device *)cq_context;
821
822	tasklet_schedule(&device->cq_tasklet);
823}
824