1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
4  * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the
10  * OpenIB.org BSD license below:
11  *
12  *     Redistribution and use in source and binary forms, with or
13  *     without modification, are permitted provided that the following
14  *     conditions are met:
15  *
16  *	- Redistributions of source code must retain the above
17  *	  copyright notice, this list of conditions and the following
18  *	  disclaimer.
19  *
20  *	- Redistributions in binary form must reproduce the above
21  *	  copyright notice, this list of conditions and the following
22  *	  disclaimer in the documentation and/or other materials
23  *	  provided with the distribution.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32  * SOFTWARE.
33  */
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/slab.h>
37 #include <linux/delay.h>
38 
39 #include "iscsi_iser.h"
40 
41 #define ISCSI_ISER_MAX_CONN	8
42 #define ISER_MAX_RX_LEN		(ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
43 #define ISER_MAX_TX_LEN		(ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)
44 #define ISER_MAX_CQ_LEN		(ISER_MAX_RX_LEN + ISER_MAX_TX_LEN + \
45 				 ISCSI_ISER_MAX_CONN)
46 
47 static int iser_cq_poll_limit = 512;
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 
52 static void iser_cq_event_callback(struct ib_event *cause, void *context)
53 {
54 	iser_err("got cq event %d \n", cause->event);
55 }
56 
57 static void iser_qp_event_callback(struct ib_event *cause, void *context)
58 {
59 	iser_err("got qp event %d\n",cause->event);
60 }
61 
62 static void iser_event_handler(struct ib_event_handler *handler,
63 				struct ib_event *event)
64 {
65 	iser_err("async event %d on device %s port %d\n", event->event,
66 		event->device->name, event->element.port_num);
67 }
68 
69 /**
70  * iser_create_device_ib_res - creates Protection Domain (PD), Completion
71  * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
72  * the adapator.
73  *
74  * returns 0 on success, -1 on failure
75  */
76 static int iser_create_device_ib_res(struct iser_device *device)
77 {
78 	struct ib_device_attr *dev_attr = &device->dev_attr;
79 	int ret, i;
80 
81 	ret = ib_query_device(device->ib_device, dev_attr);
82 	if (ret) {
83 		pr_warn("Query device failed for %s\n", device->ib_device->name);
84 		return ret;
85 	}
86 
87 	/* Assign function handles  - based on FMR support */
88 	if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
89 	    device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
90 		iser_info("FMR supported, using FMR for registration\n");
91 		device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
92 		device->iser_free_rdma_reg_res = iser_free_fmr_pool;
93 		device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
94 		device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
95 	} else
96 	if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
97 		iser_info("FastReg supported, using FastReg for registration\n");
98 		device->iser_alloc_rdma_reg_res = iser_create_fastreg_pool;
99 		device->iser_free_rdma_reg_res = iser_free_fastreg_pool;
100 		device->iser_reg_rdma_mem = iser_reg_rdma_mem_fastreg;
101 		device->iser_unreg_rdma_mem = iser_unreg_mem_fastreg;
102 	} else {
103 		iser_err("IB device does not support FMRs nor FastRegs, can't register memory\n");
104 		return -1;
105 	}
106 
107 	device->comps_used = min(ISER_MAX_CQ,
108 				 device->ib_device->num_comp_vectors);
109 	iser_info("using %d CQs, device %s supports %d vectors\n",
110 		  device->comps_used, device->ib_device->name,
111 		  device->ib_device->num_comp_vectors);
112 
113 	device->pd = ib_alloc_pd(device->ib_device);
114 	if (IS_ERR(device->pd))
115 		goto pd_err;
116 
117 	for (i = 0; i < device->comps_used; i++) {
118 		struct iser_comp *comp = &device->comps[i];
119 
120 		comp->device = device;
121 		comp->cq = ib_create_cq(device->ib_device,
122 					iser_cq_callback,
123 					iser_cq_event_callback,
124 					(void *)comp,
125 					ISER_MAX_CQ_LEN, i);
126 		if (IS_ERR(comp->cq)) {
127 			comp->cq = NULL;
128 			goto cq_err;
129 		}
130 
131 		if (ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP))
132 			goto cq_err;
133 
134 		tasklet_init(&comp->tasklet, iser_cq_tasklet_fn,
135 			     (unsigned long)comp);
136 	}
137 
138 	device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
139 				   IB_ACCESS_REMOTE_WRITE |
140 				   IB_ACCESS_REMOTE_READ);
141 	if (IS_ERR(device->mr))
142 		goto dma_mr_err;
143 
144 	INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
145 				iser_event_handler);
146 	if (ib_register_event_handler(&device->event_handler))
147 		goto handler_err;
148 
149 	return 0;
150 
151 handler_err:
152 	ib_dereg_mr(device->mr);
153 dma_mr_err:
154 	for (i = 0; i < device->comps_used; i++)
155 		tasklet_kill(&device->comps[i].tasklet);
156 cq_err:
157 	for (i = 0; i < device->comps_used; i++) {
158 		struct iser_comp *comp = &device->comps[i];
159 
160 		if (comp->cq)
161 			ib_destroy_cq(comp->cq);
162 	}
163 	ib_dealloc_pd(device->pd);
164 pd_err:
165 	iser_err("failed to allocate an IB resource\n");
166 	return -1;
167 }
168 
169 /**
170  * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
171  * CQ and PD created with the device associated with the adapator.
172  */
173 static void iser_free_device_ib_res(struct iser_device *device)
174 {
175 	int i;
176 	BUG_ON(device->mr == NULL);
177 
178 	for (i = 0; i < device->comps_used; i++) {
179 		struct iser_comp *comp = &device->comps[i];
180 
181 		tasklet_kill(&comp->tasklet);
182 		ib_destroy_cq(comp->cq);
183 		comp->cq = NULL;
184 	}
185 
186 	(void)ib_unregister_event_handler(&device->event_handler);
187 	(void)ib_dereg_mr(device->mr);
188 	(void)ib_dealloc_pd(device->pd);
189 
190 	device->mr = NULL;
191 	device->pd = NULL;
192 }
193 
194 /**
195  * iser_create_fmr_pool - Creates FMR pool and page_vector
196  *
197  * returns 0 on success, or errno code on failure
198  */
199 int iser_create_fmr_pool(struct ib_conn *ib_conn, unsigned cmds_max)
200 {
201 	struct iser_device *device = ib_conn->device;
202 	struct ib_fmr_pool_param params;
203 	int ret = -ENOMEM;
204 
205 	ib_conn->fmr.page_vec = kmalloc(sizeof(*ib_conn->fmr.page_vec) +
206 					(sizeof(u64)*(ISCSI_ISER_SG_TABLESIZE + 1)),
207 					GFP_KERNEL);
208 	if (!ib_conn->fmr.page_vec)
209 		return ret;
210 
211 	ib_conn->fmr.page_vec->pages = (u64 *)(ib_conn->fmr.page_vec + 1);
212 
213 	params.page_shift        = SHIFT_4K;
214 	/* when the first/last SG element are not start/end *
215 	 * page aligned, the map whould be of N+1 pages     */
216 	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
217 	/* make the pool size twice the max number of SCSI commands *
218 	 * the ML is expected to queue, watermark for unmap at 50%  */
219 	params.pool_size	 = cmds_max * 2;
220 	params.dirty_watermark	 = cmds_max;
221 	params.cache		 = 0;
222 	params.flush_function	 = NULL;
223 	params.access		 = (IB_ACCESS_LOCAL_WRITE  |
224 				    IB_ACCESS_REMOTE_WRITE |
225 				    IB_ACCESS_REMOTE_READ);
226 
227 	ib_conn->fmr.pool = ib_create_fmr_pool(device->pd, &params);
228 	if (!IS_ERR(ib_conn->fmr.pool))
229 		return 0;
230 
231 	/* no FMR => no need for page_vec */
232 	kfree(ib_conn->fmr.page_vec);
233 	ib_conn->fmr.page_vec = NULL;
234 
235 	ret = PTR_ERR(ib_conn->fmr.pool);
236 	ib_conn->fmr.pool = NULL;
237 	if (ret != -ENOSYS) {
238 		iser_err("FMR allocation failed, err %d\n", ret);
239 		return ret;
240 	} else {
241 		iser_warn("FMRs are not supported, using unaligned mode\n");
242 		return 0;
243 	}
244 }
245 
246 /**
247  * iser_free_fmr_pool - releases the FMR pool and page vec
248  */
249 void iser_free_fmr_pool(struct ib_conn *ib_conn)
250 {
251 	iser_info("freeing conn %p fmr pool %p\n",
252 		  ib_conn, ib_conn->fmr.pool);
253 
254 	if (ib_conn->fmr.pool != NULL)
255 		ib_destroy_fmr_pool(ib_conn->fmr.pool);
256 
257 	ib_conn->fmr.pool = NULL;
258 
259 	kfree(ib_conn->fmr.page_vec);
260 	ib_conn->fmr.page_vec = NULL;
261 }
262 
263 static int
264 iser_create_fastreg_desc(struct ib_device *ib_device, struct ib_pd *pd,
265 			 bool pi_enable, struct fast_reg_descriptor *desc)
266 {
267 	int ret;
268 
269 	desc->data_frpl = ib_alloc_fast_reg_page_list(ib_device,
270 						      ISCSI_ISER_SG_TABLESIZE + 1);
271 	if (IS_ERR(desc->data_frpl)) {
272 		ret = PTR_ERR(desc->data_frpl);
273 		iser_err("Failed to allocate ib_fast_reg_page_list err=%d\n",
274 			 ret);
275 		return PTR_ERR(desc->data_frpl);
276 	}
277 
278 	desc->data_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE + 1);
279 	if (IS_ERR(desc->data_mr)) {
280 		ret = PTR_ERR(desc->data_mr);
281 		iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
282 		goto fast_reg_mr_failure;
283 	}
284 	desc->reg_indicators |= ISER_DATA_KEY_VALID;
285 
286 	if (pi_enable) {
287 		struct ib_mr_init_attr mr_init_attr = {0};
288 		struct iser_pi_context *pi_ctx = NULL;
289 
290 		desc->pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
291 		if (!desc->pi_ctx) {
292 			iser_err("Failed to allocate pi context\n");
293 			ret = -ENOMEM;
294 			goto pi_ctx_alloc_failure;
295 		}
296 		pi_ctx = desc->pi_ctx;
297 
298 		pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(ib_device,
299 						    ISCSI_ISER_SG_TABLESIZE);
300 		if (IS_ERR(pi_ctx->prot_frpl)) {
301 			ret = PTR_ERR(pi_ctx->prot_frpl);
302 			iser_err("Failed to allocate prot frpl ret=%d\n",
303 				 ret);
304 			goto prot_frpl_failure;
305 		}
306 
307 		pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd,
308 						ISCSI_ISER_SG_TABLESIZE + 1);
309 		if (IS_ERR(pi_ctx->prot_mr)) {
310 			ret = PTR_ERR(pi_ctx->prot_mr);
311 			iser_err("Failed to allocate prot frmr ret=%d\n",
312 				 ret);
313 			goto prot_mr_failure;
314 		}
315 		desc->reg_indicators |= ISER_PROT_KEY_VALID;
316 
317 		mr_init_attr.max_reg_descriptors = 2;
318 		mr_init_attr.flags |= IB_MR_SIGNATURE_EN;
319 		pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
320 		if (IS_ERR(pi_ctx->sig_mr)) {
321 			ret = PTR_ERR(pi_ctx->sig_mr);
322 			iser_err("Failed to allocate signature enabled mr err=%d\n",
323 				 ret);
324 			goto sig_mr_failure;
325 		}
326 		desc->reg_indicators |= ISER_SIG_KEY_VALID;
327 	}
328 	desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
329 
330 	iser_dbg("Create fr_desc %p page_list %p\n",
331 		 desc, desc->data_frpl->page_list);
332 
333 	return 0;
334 sig_mr_failure:
335 	ib_dereg_mr(desc->pi_ctx->prot_mr);
336 prot_mr_failure:
337 	ib_free_fast_reg_page_list(desc->pi_ctx->prot_frpl);
338 prot_frpl_failure:
339 	kfree(desc->pi_ctx);
340 pi_ctx_alloc_failure:
341 	ib_dereg_mr(desc->data_mr);
342 fast_reg_mr_failure:
343 	ib_free_fast_reg_page_list(desc->data_frpl);
344 
345 	return ret;
346 }
347 
348 /**
349  * iser_create_fastreg_pool - Creates pool of fast_reg descriptors
350  * for fast registration work requests.
351  * returns 0 on success, or errno code on failure
352  */
353 int iser_create_fastreg_pool(struct ib_conn *ib_conn, unsigned cmds_max)
354 {
355 	struct iser_device *device = ib_conn->device;
356 	struct fast_reg_descriptor *desc;
357 	int i, ret;
358 
359 	INIT_LIST_HEAD(&ib_conn->fastreg.pool);
360 	ib_conn->fastreg.pool_size = 0;
361 	for (i = 0; i < cmds_max; i++) {
362 		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
363 		if (!desc) {
364 			iser_err("Failed to allocate a new fast_reg descriptor\n");
365 			ret = -ENOMEM;
366 			goto err;
367 		}
368 
369 		ret = iser_create_fastreg_desc(device->ib_device, device->pd,
370 					       ib_conn->pi_support, desc);
371 		if (ret) {
372 			iser_err("Failed to create fastreg descriptor err=%d\n",
373 				 ret);
374 			kfree(desc);
375 			goto err;
376 		}
377 
378 		list_add_tail(&desc->list, &ib_conn->fastreg.pool);
379 		ib_conn->fastreg.pool_size++;
380 	}
381 
382 	return 0;
383 
384 err:
385 	iser_free_fastreg_pool(ib_conn);
386 	return ret;
387 }
388 
389 /**
390  * iser_free_fastreg_pool - releases the pool of fast_reg descriptors
391  */
392 void iser_free_fastreg_pool(struct ib_conn *ib_conn)
393 {
394 	struct fast_reg_descriptor *desc, *tmp;
395 	int i = 0;
396 
397 	if (list_empty(&ib_conn->fastreg.pool))
398 		return;
399 
400 	iser_info("freeing conn %p fr pool\n", ib_conn);
401 
402 	list_for_each_entry_safe(desc, tmp, &ib_conn->fastreg.pool, list) {
403 		list_del(&desc->list);
404 		ib_free_fast_reg_page_list(desc->data_frpl);
405 		ib_dereg_mr(desc->data_mr);
406 		if (desc->pi_ctx) {
407 			ib_free_fast_reg_page_list(desc->pi_ctx->prot_frpl);
408 			ib_dereg_mr(desc->pi_ctx->prot_mr);
409 			ib_destroy_mr(desc->pi_ctx->sig_mr);
410 			kfree(desc->pi_ctx);
411 		}
412 		kfree(desc);
413 		++i;
414 	}
415 
416 	if (i < ib_conn->fastreg.pool_size)
417 		iser_warn("pool still has %d regions registered\n",
418 			  ib_conn->fastreg.pool_size - i);
419 }
420 
421 /**
422  * iser_create_ib_conn_res - Queue-Pair (QP)
423  *
424  * returns 0 on success, -1 on failure
425  */
426 static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
427 {
428 	struct iser_device	*device;
429 	struct ib_qp_init_attr	init_attr;
430 	int			ret = -ENOMEM;
431 	int index, min_index = 0;
432 
433 	BUG_ON(ib_conn->device == NULL);
434 
435 	device = ib_conn->device;
436 
437 	memset(&init_attr, 0, sizeof init_attr);
438 
439 	mutex_lock(&ig.connlist_mutex);
440 	/* select the CQ with the minimal number of usages */
441 	for (index = 0; index < device->comps_used; index++) {
442 		if (device->comps[index].active_qps <
443 		    device->comps[min_index].active_qps)
444 			min_index = index;
445 	}
446 	ib_conn->comp = &device->comps[min_index];
447 	ib_conn->comp->active_qps++;
448 	mutex_unlock(&ig.connlist_mutex);
449 	iser_info("cq index %d used for ib_conn %p\n", min_index, ib_conn);
450 
451 	init_attr.event_handler = iser_qp_event_callback;
452 	init_attr.qp_context	= (void *)ib_conn;
453 	init_attr.send_cq	= ib_conn->comp->cq;
454 	init_attr.recv_cq	= ib_conn->comp->cq;
455 	init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
456 	init_attr.cap.max_send_sge = 2;
457 	init_attr.cap.max_recv_sge = 1;
458 	init_attr.sq_sig_type	= IB_SIGNAL_REQ_WR;
459 	init_attr.qp_type	= IB_QPT_RC;
460 	if (ib_conn->pi_support) {
461 		init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
462 		init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
463 	} else {
464 		init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS + 1;
465 	}
466 
467 	ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
468 	if (ret)
469 		goto out_err;
470 
471 	ib_conn->qp = ib_conn->cma_id->qp;
472 	iser_info("setting conn %p cma_id %p qp %p\n",
473 		  ib_conn, ib_conn->cma_id,
474 		  ib_conn->cma_id->qp);
475 	return ret;
476 
477 out_err:
478 	iser_err("unable to alloc mem or create resource, err %d\n", ret);
479 	return ret;
480 }
481 
482 /**
483  * based on the resolved device node GUID see if there already allocated
484  * device for this device. If there's no such, create one.
485  */
486 static
487 struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
488 {
489 	struct iser_device *device;
490 
491 	mutex_lock(&ig.device_list_mutex);
492 
493 	list_for_each_entry(device, &ig.device_list, ig_list)
494 		/* find if there's a match using the node GUID */
495 		if (device->ib_device->node_guid == cma_id->device->node_guid)
496 			goto inc_refcnt;
497 
498 	device = kzalloc(sizeof *device, GFP_KERNEL);
499 	if (device == NULL)
500 		goto out;
501 
502 	/* assign this device to the device */
503 	device->ib_device = cma_id->device;
504 	/* init the device and link it into ig device list */
505 	if (iser_create_device_ib_res(device)) {
506 		kfree(device);
507 		device = NULL;
508 		goto out;
509 	}
510 	list_add(&device->ig_list, &ig.device_list);
511 
512 inc_refcnt:
513 	device->refcount++;
514 out:
515 	mutex_unlock(&ig.device_list_mutex);
516 	return device;
517 }
518 
519 /* if there's no demand for this device, release it */
520 static void iser_device_try_release(struct iser_device *device)
521 {
522 	mutex_lock(&ig.device_list_mutex);
523 	device->refcount--;
524 	iser_info("device %p refcount %d\n", device, device->refcount);
525 	if (!device->refcount) {
526 		iser_free_device_ib_res(device);
527 		list_del(&device->ig_list);
528 		kfree(device);
529 	}
530 	mutex_unlock(&ig.device_list_mutex);
531 }
532 
533 /**
534  * Called with state mutex held
535  **/
536 static int iser_conn_state_comp_exch(struct iser_conn *iser_conn,
537 				     enum iser_conn_state comp,
538 				     enum iser_conn_state exch)
539 {
540 	int ret;
541 
542 	ret = (iser_conn->state == comp);
543 	if (ret)
544 		iser_conn->state = exch;
545 
546 	return ret;
547 }
548 
549 void iser_release_work(struct work_struct *work)
550 {
551 	struct iser_conn *iser_conn;
552 
553 	iser_conn = container_of(work, struct iser_conn, release_work);
554 
555 	/* Wait for conn_stop to complete */
556 	wait_for_completion(&iser_conn->stop_completion);
557 	/* Wait for IB resouces cleanup to complete */
558 	wait_for_completion(&iser_conn->ib_completion);
559 
560 	mutex_lock(&iser_conn->state_mutex);
561 	iser_conn->state = ISER_CONN_DOWN;
562 	mutex_unlock(&iser_conn->state_mutex);
563 
564 	iser_conn_release(iser_conn);
565 }
566 
567 /**
568  * iser_free_ib_conn_res - release IB related resources
569  * @iser_conn: iser connection struct
570  * @destroy_device: indicator if we need to try to release
571  *     the iser device (only iscsi shutdown and DEVICE_REMOVAL
572  *     will use this.
573  *
574  * This routine is called with the iser state mutex held
575  * so the cm_id removal is out of here. It is Safe to
576  * be invoked multiple times.
577  */
578 static void iser_free_ib_conn_res(struct iser_conn *iser_conn,
579 				  bool destroy_device)
580 {
581 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
582 	struct iser_device *device = ib_conn->device;
583 
584 	iser_info("freeing conn %p cma_id %p qp %p\n",
585 		  iser_conn, ib_conn->cma_id, ib_conn->qp);
586 
587 	iser_free_rx_descriptors(iser_conn);
588 
589 	if (ib_conn->qp != NULL) {
590 		ib_conn->comp->active_qps--;
591 		rdma_destroy_qp(ib_conn->cma_id);
592 		ib_conn->qp = NULL;
593 	}
594 
595 	if (destroy_device && device != NULL) {
596 		iser_device_try_release(device);
597 		ib_conn->device = NULL;
598 	}
599 }
600 
601 /**
602  * Frees all conn objects and deallocs conn descriptor
603  */
604 void iser_conn_release(struct iser_conn *iser_conn)
605 {
606 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
607 
608 	mutex_lock(&ig.connlist_mutex);
609 	list_del(&iser_conn->conn_list);
610 	mutex_unlock(&ig.connlist_mutex);
611 
612 	mutex_lock(&iser_conn->state_mutex);
613 	if (iser_conn->state != ISER_CONN_DOWN)
614 		iser_warn("iser conn %p state %d, expected state down.\n",
615 			  iser_conn, iser_conn->state);
616 	/*
617 	 * In case we never got to bind stage, we still need to
618 	 * release IB resources (which is safe to call more than once).
619 	 */
620 	iser_free_ib_conn_res(iser_conn, true);
621 	mutex_unlock(&iser_conn->state_mutex);
622 
623 	if (ib_conn->cma_id != NULL) {
624 		rdma_destroy_id(ib_conn->cma_id);
625 		ib_conn->cma_id = NULL;
626 	}
627 
628 	kfree(iser_conn);
629 }
630 
631 /**
632  * triggers start of the disconnect procedures and wait for them to be done
633  * Called with state mutex held
634  */
635 int iser_conn_terminate(struct iser_conn *iser_conn)
636 {
637 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
638 	struct ib_send_wr *bad_wr;
639 	int err = 0;
640 
641 	/* terminate the iser conn only if the conn state is UP */
642 	if (!iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
643 				       ISER_CONN_TERMINATING))
644 		return 0;
645 
646 	iser_info("iser_conn %p state %d\n", iser_conn, iser_conn->state);
647 
648 	/* suspend queuing of new iscsi commands */
649 	if (iser_conn->iscsi_conn)
650 		iscsi_suspend_queue(iser_conn->iscsi_conn);
651 
652 	/*
653 	 * In case we didn't already clean up the cma_id (peer initiated
654 	 * a disconnection), we need to Cause the CMA to change the QP
655 	 * state to ERROR.
656 	 */
657 	if (ib_conn->cma_id) {
658 		err = rdma_disconnect(ib_conn->cma_id);
659 		if (err)
660 			iser_err("Failed to disconnect, conn: 0x%p err %d\n",
661 				 iser_conn, err);
662 
663 		/* post an indication that all flush errors were consumed */
664 		err = ib_post_send(ib_conn->qp, &ib_conn->beacon, &bad_wr);
665 		if (err)
666 			iser_err("conn %p failed to post beacon", ib_conn);
667 
668 		wait_for_completion(&ib_conn->flush_comp);
669 	}
670 
671 	return 1;
672 }
673 
674 /**
675  * Called with state mutex held
676  **/
677 static void iser_connect_error(struct rdma_cm_id *cma_id)
678 {
679 	struct iser_conn *iser_conn;
680 
681 	iser_conn = (struct iser_conn *)cma_id->context;
682 	iser_conn->state = ISER_CONN_DOWN;
683 }
684 
685 /**
686  * Called with state mutex held
687  **/
688 static void iser_addr_handler(struct rdma_cm_id *cma_id)
689 {
690 	struct iser_device *device;
691 	struct iser_conn   *iser_conn;
692 	struct ib_conn   *ib_conn;
693 	int    ret;
694 
695 	iser_conn = (struct iser_conn *)cma_id->context;
696 	if (iser_conn->state != ISER_CONN_PENDING)
697 		/* bailout */
698 		return;
699 
700 	ib_conn = &iser_conn->ib_conn;
701 	device = iser_device_find_by_ib_device(cma_id);
702 	if (!device) {
703 		iser_err("device lookup/creation failed\n");
704 		iser_connect_error(cma_id);
705 		return;
706 	}
707 
708 	ib_conn->device = device;
709 
710 	/* connection T10-PI support */
711 	if (iser_pi_enable) {
712 		if (!(device->dev_attr.device_cap_flags &
713 		      IB_DEVICE_SIGNATURE_HANDOVER)) {
714 			iser_warn("T10-PI requested but not supported on %s, "
715 				  "continue without T10-PI\n",
716 				  ib_conn->device->ib_device->name);
717 			ib_conn->pi_support = false;
718 		} else {
719 			ib_conn->pi_support = true;
720 		}
721 	}
722 
723 	ret = rdma_resolve_route(cma_id, 1000);
724 	if (ret) {
725 		iser_err("resolve route failed: %d\n", ret);
726 		iser_connect_error(cma_id);
727 		return;
728 	}
729 }
730 
731 /**
732  * Called with state mutex held
733  **/
734 static void iser_route_handler(struct rdma_cm_id *cma_id)
735 {
736 	struct rdma_conn_param conn_param;
737 	int    ret;
738 	struct iser_cm_hdr req_hdr;
739 	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
740 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
741 	struct iser_device *device = ib_conn->device;
742 
743 	if (iser_conn->state != ISER_CONN_PENDING)
744 		/* bailout */
745 		return;
746 
747 	ret = iser_create_ib_conn_res(ib_conn);
748 	if (ret)
749 		goto failure;
750 
751 	memset(&conn_param, 0, sizeof conn_param);
752 	conn_param.responder_resources = device->dev_attr.max_qp_rd_atom;
753 	conn_param.initiator_depth     = 1;
754 	conn_param.retry_count	       = 7;
755 	conn_param.rnr_retry_count     = 6;
756 
757 	memset(&req_hdr, 0, sizeof(req_hdr));
758 	req_hdr.flags = (ISER_ZBVA_NOT_SUPPORTED |
759 			ISER_SEND_W_INV_NOT_SUPPORTED);
760 	conn_param.private_data		= (void *)&req_hdr;
761 	conn_param.private_data_len	= sizeof(struct iser_cm_hdr);
762 
763 	ret = rdma_connect(cma_id, &conn_param);
764 	if (ret) {
765 		iser_err("failure connecting: %d\n", ret);
766 		goto failure;
767 	}
768 
769 	return;
770 failure:
771 	iser_connect_error(cma_id);
772 }
773 
774 static void iser_connected_handler(struct rdma_cm_id *cma_id)
775 {
776 	struct iser_conn *iser_conn;
777 	struct ib_qp_attr attr;
778 	struct ib_qp_init_attr init_attr;
779 
780 	iser_conn = (struct iser_conn *)cma_id->context;
781 	if (iser_conn->state != ISER_CONN_PENDING)
782 		/* bailout */
783 		return;
784 
785 	(void)ib_query_qp(cma_id->qp, &attr, ~0, &init_attr);
786 	iser_info("remote qpn:%x my qpn:%x\n", attr.dest_qp_num, cma_id->qp->qp_num);
787 
788 	iser_conn->state = ISER_CONN_UP;
789 	complete(&iser_conn->up_completion);
790 }
791 
792 static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
793 {
794 	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
795 
796 	if (iser_conn_terminate(iser_conn)) {
797 		if (iser_conn->iscsi_conn)
798 			iscsi_conn_failure(iser_conn->iscsi_conn,
799 					   ISCSI_ERR_CONN_FAILED);
800 		else
801 			iser_err("iscsi_iser connection isn't bound\n");
802 	}
803 }
804 
805 static void iser_cleanup_handler(struct rdma_cm_id *cma_id,
806 				 bool destroy_device)
807 {
808 	struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
809 
810 	/*
811 	 * We are not guaranteed that we visited disconnected_handler
812 	 * by now, call it here to be safe that we handle CM drep
813 	 * and flush errors.
814 	 */
815 	iser_disconnected_handler(cma_id);
816 	iser_free_ib_conn_res(iser_conn, destroy_device);
817 	complete(&iser_conn->ib_completion);
818 };
819 
820 static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
821 {
822 	struct iser_conn *iser_conn;
823 	int ret = 0;
824 
825 	iser_conn = (struct iser_conn *)cma_id->context;
826 	iser_info("event %d status %d conn %p id %p\n",
827 		  event->event, event->status, cma_id->context, cma_id);
828 
829 	mutex_lock(&iser_conn->state_mutex);
830 	switch (event->event) {
831 	case RDMA_CM_EVENT_ADDR_RESOLVED:
832 		iser_addr_handler(cma_id);
833 		break;
834 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
835 		iser_route_handler(cma_id);
836 		break;
837 	case RDMA_CM_EVENT_ESTABLISHED:
838 		iser_connected_handler(cma_id);
839 		break;
840 	case RDMA_CM_EVENT_ADDR_ERROR:
841 	case RDMA_CM_EVENT_ROUTE_ERROR:
842 	case RDMA_CM_EVENT_CONNECT_ERROR:
843 	case RDMA_CM_EVENT_UNREACHABLE:
844 	case RDMA_CM_EVENT_REJECTED:
845 		iser_connect_error(cma_id);
846 		break;
847 	case RDMA_CM_EVENT_DISCONNECTED:
848 	case RDMA_CM_EVENT_ADDR_CHANGE:
849 		iser_disconnected_handler(cma_id);
850 		break;
851 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
852 		/*
853 		 * we *must* destroy the device as we cannot rely
854 		 * on iscsid to be around to initiate error handling.
855 		 * also implicitly destroy the cma_id.
856 		 */
857 		iser_cleanup_handler(cma_id, true);
858 		iser_conn->ib_conn.cma_id = NULL;
859 		ret = 1;
860 		break;
861 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
862 		iser_cleanup_handler(cma_id, false);
863 		break;
864 	default:
865 		iser_err("Unexpected RDMA CM event (%d)\n", event->event);
866 		break;
867 	}
868 	mutex_unlock(&iser_conn->state_mutex);
869 
870 	return ret;
871 }
872 
873 void iser_conn_init(struct iser_conn *iser_conn)
874 {
875 	iser_conn->state = ISER_CONN_INIT;
876 	iser_conn->ib_conn.post_recv_buf_count = 0;
877 	init_completion(&iser_conn->ib_conn.flush_comp);
878 	init_completion(&iser_conn->stop_completion);
879 	init_completion(&iser_conn->ib_completion);
880 	init_completion(&iser_conn->up_completion);
881 	INIT_LIST_HEAD(&iser_conn->conn_list);
882 	spin_lock_init(&iser_conn->ib_conn.lock);
883 	mutex_init(&iser_conn->state_mutex);
884 }
885 
886  /**
887  * starts the process of connecting to the target
888  * sleeps until the connection is established or rejected
889  */
890 int iser_connect(struct iser_conn   *iser_conn,
891 		 struct sockaddr    *src_addr,
892 		 struct sockaddr    *dst_addr,
893 		 int                 non_blocking)
894 {
895 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
896 	int err = 0;
897 
898 	mutex_lock(&iser_conn->state_mutex);
899 
900 	sprintf(iser_conn->name, "%pISp", dst_addr);
901 
902 	iser_info("connecting to: %s\n", iser_conn->name);
903 
904 	/* the device is known only --after-- address resolution */
905 	ib_conn->device = NULL;
906 
907 	iser_conn->state = ISER_CONN_PENDING;
908 
909 	ib_conn->beacon.wr_id = ISER_BEACON_WRID;
910 	ib_conn->beacon.opcode = IB_WR_SEND;
911 
912 	ib_conn->cma_id = rdma_create_id(iser_cma_handler,
913 					 (void *)iser_conn,
914 					 RDMA_PS_TCP, IB_QPT_RC);
915 	if (IS_ERR(ib_conn->cma_id)) {
916 		err = PTR_ERR(ib_conn->cma_id);
917 		iser_err("rdma_create_id failed: %d\n", err);
918 		goto id_failure;
919 	}
920 
921 	err = rdma_resolve_addr(ib_conn->cma_id, src_addr, dst_addr, 1000);
922 	if (err) {
923 		iser_err("rdma_resolve_addr failed: %d\n", err);
924 		goto addr_failure;
925 	}
926 
927 	if (!non_blocking) {
928 		wait_for_completion_interruptible(&iser_conn->up_completion);
929 
930 		if (iser_conn->state != ISER_CONN_UP) {
931 			err =  -EIO;
932 			goto connect_failure;
933 		}
934 	}
935 	mutex_unlock(&iser_conn->state_mutex);
936 
937 	mutex_lock(&ig.connlist_mutex);
938 	list_add(&iser_conn->conn_list, &ig.connlist);
939 	mutex_unlock(&ig.connlist_mutex);
940 	return 0;
941 
942 id_failure:
943 	ib_conn->cma_id = NULL;
944 addr_failure:
945 	iser_conn->state = ISER_CONN_DOWN;
946 connect_failure:
947 	mutex_unlock(&iser_conn->state_mutex);
948 	iser_conn_release(iser_conn);
949 	return err;
950 }
951 
952 /**
953  * iser_reg_page_vec - Register physical memory
954  *
955  * returns: 0 on success, errno code on failure
956  */
957 int iser_reg_page_vec(struct ib_conn *ib_conn,
958 		      struct iser_page_vec *page_vec,
959 		      struct iser_mem_reg  *mem_reg)
960 {
961 	struct ib_pool_fmr *mem;
962 	u64		   io_addr;
963 	u64		   *page_list;
964 	int		   status;
965 
966 	page_list = page_vec->pages;
967 	io_addr	  = page_list[0];
968 
969 	mem  = ib_fmr_pool_map_phys(ib_conn->fmr.pool,
970 				    page_list,
971 				    page_vec->length,
972 				    io_addr);
973 
974 	if (IS_ERR(mem)) {
975 		status = (int)PTR_ERR(mem);
976 		iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
977 		return status;
978 	}
979 
980 	mem_reg->lkey  = mem->fmr->lkey;
981 	mem_reg->rkey  = mem->fmr->rkey;
982 	mem_reg->len   = page_vec->length * SIZE_4K;
983 	mem_reg->va    = io_addr;
984 	mem_reg->is_mr = 1;
985 	mem_reg->mem_h = (void *)mem;
986 
987 	mem_reg->va   += page_vec->offset;
988 	mem_reg->len   = page_vec->data_size;
989 
990 	iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
991 		 "entry[0]: (0x%08lx,%ld)] -> "
992 		 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
993 		 page_vec, page_vec->length,
994 		 (unsigned long)page_vec->pages[0],
995 		 (unsigned long)page_vec->data_size,
996 		 (unsigned int)mem_reg->lkey, mem_reg->mem_h,
997 		 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
998 	return 0;
999 }
1000 
1001 /**
1002  * Unregister (previosuly registered using FMR) memory.
1003  * If memory is non-FMR does nothing.
1004  */
1005 void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
1006 			enum iser_data_dir cmd_dir)
1007 {
1008 	struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
1009 	int ret;
1010 
1011 	if (!reg->is_mr)
1012 		return;
1013 
1014 	iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
1015 
1016 	ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
1017 	if (ret)
1018 		iser_err("ib_fmr_pool_unmap failed %d\n", ret);
1019 
1020 	reg->mem_h = NULL;
1021 }
1022 
1023 void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
1024 			    enum iser_data_dir cmd_dir)
1025 {
1026 	struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
1027 	struct iser_conn *iser_conn = iser_task->iser_conn;
1028 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
1029 	struct fast_reg_descriptor *desc = reg->mem_h;
1030 
1031 	if (!reg->is_mr)
1032 		return;
1033 
1034 	reg->mem_h = NULL;
1035 	reg->is_mr = 0;
1036 	spin_lock_bh(&ib_conn->lock);
1037 	list_add_tail(&desc->list, &ib_conn->fastreg.pool);
1038 	spin_unlock_bh(&ib_conn->lock);
1039 }
1040 
1041 int iser_post_recvl(struct iser_conn *iser_conn)
1042 {
1043 	struct ib_recv_wr rx_wr, *rx_wr_failed;
1044 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
1045 	struct ib_sge	  sge;
1046 	int ib_ret;
1047 
1048 	sge.addr   = iser_conn->login_resp_dma;
1049 	sge.length = ISER_RX_LOGIN_SIZE;
1050 	sge.lkey   = ib_conn->device->mr->lkey;
1051 
1052 	rx_wr.wr_id   = (unsigned long)iser_conn->login_resp_buf;
1053 	rx_wr.sg_list = &sge;
1054 	rx_wr.num_sge = 1;
1055 	rx_wr.next    = NULL;
1056 
1057 	ib_conn->post_recv_buf_count++;
1058 	ib_ret	= ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
1059 	if (ib_ret) {
1060 		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1061 		ib_conn->post_recv_buf_count--;
1062 	}
1063 	return ib_ret;
1064 }
1065 
1066 int iser_post_recvm(struct iser_conn *iser_conn, int count)
1067 {
1068 	struct ib_recv_wr *rx_wr, *rx_wr_failed;
1069 	int i, ib_ret;
1070 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
1071 	unsigned int my_rx_head = iser_conn->rx_desc_head;
1072 	struct iser_rx_desc *rx_desc;
1073 
1074 	for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
1075 		rx_desc		= &iser_conn->rx_descs[my_rx_head];
1076 		rx_wr->wr_id	= (unsigned long)rx_desc;
1077 		rx_wr->sg_list	= &rx_desc->rx_sg;
1078 		rx_wr->num_sge	= 1;
1079 		rx_wr->next	= rx_wr + 1;
1080 		my_rx_head = (my_rx_head + 1) & iser_conn->qp_max_recv_dtos_mask;
1081 	}
1082 
1083 	rx_wr--;
1084 	rx_wr->next = NULL; /* mark end of work requests list */
1085 
1086 	ib_conn->post_recv_buf_count += count;
1087 	ib_ret	= ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
1088 	if (ib_ret) {
1089 		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1090 		ib_conn->post_recv_buf_count -= count;
1091 	} else
1092 		iser_conn->rx_desc_head = my_rx_head;
1093 	return ib_ret;
1094 }
1095 
1096 
1097 /**
1098  * iser_start_send - Initiate a Send DTO operation
1099  *
1100  * returns 0 on success, -1 on failure
1101  */
1102 int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc,
1103 		   bool signal)
1104 {
1105 	int		  ib_ret;
1106 	struct ib_send_wr send_wr, *send_wr_failed;
1107 
1108 	ib_dma_sync_single_for_device(ib_conn->device->ib_device,
1109 				      tx_desc->dma_addr, ISER_HEADERS_LEN,
1110 				      DMA_TO_DEVICE);
1111 
1112 	send_wr.next	   = NULL;
1113 	send_wr.wr_id	   = (unsigned long)tx_desc;
1114 	send_wr.sg_list	   = tx_desc->tx_sg;
1115 	send_wr.num_sge	   = tx_desc->num_sge;
1116 	send_wr.opcode	   = IB_WR_SEND;
1117 	send_wr.send_flags = signal ? IB_SEND_SIGNALED : 0;
1118 
1119 	ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
1120 	if (ib_ret)
1121 		iser_err("ib_post_send failed, ret:%d\n", ib_ret);
1122 
1123 	return ib_ret;
1124 }
1125 
1126 /**
1127  * is_iser_tx_desc - Indicate if the completion wr_id
1128  *     is a TX descriptor or not.
1129  * @iser_conn: iser connection
1130  * @wr_id: completion WR identifier
1131  *
1132  * Since we cannot rely on wc opcode in FLUSH errors
1133  * we must work around it by checking if the wr_id address
1134  * falls in the iser connection rx_descs buffer. If so
1135  * it is an RX descriptor, otherwize it is a TX.
1136  */
1137 static inline bool
1138 is_iser_tx_desc(struct iser_conn *iser_conn, void *wr_id)
1139 {
1140 	void *start = iser_conn->rx_descs;
1141 	int len = iser_conn->num_rx_descs * sizeof(*iser_conn->rx_descs);
1142 
1143 	if (wr_id >= start && wr_id < start + len)
1144 		return false;
1145 
1146 	return true;
1147 }
1148 
1149 /**
1150  * iser_handle_comp_error() - Handle error completion
1151  * @ib_conn:   connection RDMA resources
1152  * @wc:        work completion
1153  *
1154  * Notes: We may handle a FLUSH error completion and in this case
1155  *        we only cleanup in case TX type was DATAOUT. For non-FLUSH
1156  *        error completion we should also notify iscsi layer that
1157  *        connection is failed (in case we passed bind stage).
1158  */
1159 static void
1160 iser_handle_comp_error(struct ib_conn *ib_conn,
1161 		       struct ib_wc *wc)
1162 {
1163 	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
1164 						   ib_conn);
1165 
1166 	if (wc->status != IB_WC_WR_FLUSH_ERR)
1167 		if (iser_conn->iscsi_conn)
1168 			iscsi_conn_failure(iser_conn->iscsi_conn,
1169 					   ISCSI_ERR_CONN_FAILED);
1170 
1171 	if (is_iser_tx_desc(iser_conn, (void *)wc->wr_id)) {
1172 		struct iser_tx_desc *desc = (struct iser_tx_desc *)wc->wr_id;
1173 
1174 		if (desc->type == ISCSI_TX_DATAOUT)
1175 			kmem_cache_free(ig.desc_cache, desc);
1176 	} else {
1177 		ib_conn->post_recv_buf_count--;
1178 	}
1179 }
1180 
1181 /**
1182  * iser_handle_wc - handle a single work completion
1183  * @wc: work completion
1184  *
1185  * Soft-IRQ context, work completion can be either
1186  * SEND or RECV, and can turn out successful or
1187  * with error (or flush error).
1188  */
1189 static void iser_handle_wc(struct ib_wc *wc)
1190 {
1191 	struct ib_conn *ib_conn;
1192 	struct iser_tx_desc *tx_desc;
1193 	struct iser_rx_desc *rx_desc;
1194 
1195 	ib_conn = wc->qp->qp_context;
1196 	if (wc->status == IB_WC_SUCCESS) {
1197 		if (wc->opcode == IB_WC_RECV) {
1198 			rx_desc = (struct iser_rx_desc *)wc->wr_id;
1199 			iser_rcv_completion(rx_desc, wc->byte_len,
1200 					    ib_conn);
1201 		} else
1202 		if (wc->opcode == IB_WC_SEND) {
1203 			tx_desc = (struct iser_tx_desc *)wc->wr_id;
1204 			iser_snd_completion(tx_desc, ib_conn);
1205 		} else {
1206 			iser_err("Unknown wc opcode %d\n", wc->opcode);
1207 		}
1208 	} else {
1209 		if (wc->status != IB_WC_WR_FLUSH_ERR)
1210 			iser_err("wr id %llx status %d vend_err %x\n",
1211 				 wc->wr_id, wc->status, wc->vendor_err);
1212 		else
1213 			iser_dbg("flush error: wr id %llx\n", wc->wr_id);
1214 
1215 		if (wc->wr_id != ISER_FASTREG_LI_WRID &&
1216 		    wc->wr_id != ISER_BEACON_WRID)
1217 			iser_handle_comp_error(ib_conn, wc);
1218 
1219 		/* complete in case all flush errors were consumed */
1220 		if (wc->wr_id == ISER_BEACON_WRID)
1221 			complete(&ib_conn->flush_comp);
1222 	}
1223 }
1224 
1225 /**
1226  * iser_cq_tasklet_fn - iSER completion polling loop
1227  * @data: iSER completion context
1228  *
1229  * Soft-IRQ context, polling connection CQ until
1230  * either CQ was empty or we exausted polling budget
1231  */
1232 static void iser_cq_tasklet_fn(unsigned long data)
1233 {
1234 	struct iser_comp *comp = (struct iser_comp *)data;
1235 	struct ib_cq *cq = comp->cq;
1236 	struct ib_wc *const wcs = comp->wcs;
1237 	int i, n, completed = 0;
1238 
1239 	while ((n = ib_poll_cq(cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
1240 		for (i = 0; i < n; i++)
1241 			iser_handle_wc(&wcs[i]);
1242 
1243 		completed += n;
1244 		if (completed >= iser_cq_poll_limit)
1245 			break;
1246 	}
1247 
1248 	/*
1249 	 * It is assumed here that arming CQ only once its empty
1250 	 * would not cause interrupts to be missed.
1251 	 */
1252 	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
1253 
1254 	iser_dbg("got %d completions\n", completed);
1255 }
1256 
1257 static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
1258 {
1259 	struct iser_comp *comp = cq_context;
1260 
1261 	tasklet_schedule(&comp->tasklet);
1262 }
1263 
1264 u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
1265 			     enum iser_data_dir cmd_dir, sector_t *sector)
1266 {
1267 	struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
1268 	struct fast_reg_descriptor *desc = reg->mem_h;
1269 	unsigned long sector_size = iser_task->sc->device->sector_size;
1270 	struct ib_mr_status mr_status;
1271 	int ret;
1272 
1273 	if (desc && desc->reg_indicators & ISER_FASTREG_PROTECTED) {
1274 		desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
1275 		ret = ib_check_mr_status(desc->pi_ctx->sig_mr,
1276 					 IB_MR_CHECK_SIG_STATUS, &mr_status);
1277 		if (ret) {
1278 			pr_err("ib_check_mr_status failed, ret %d\n", ret);
1279 			goto err;
1280 		}
1281 
1282 		if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
1283 			sector_t sector_off = mr_status.sig_err.sig_err_offset;
1284 
1285 			do_div(sector_off, sector_size + 8);
1286 			*sector = scsi_get_lba(iser_task->sc) + sector_off;
1287 
1288 			pr_err("PI error found type %d at sector %llx "
1289 			       "expected %x vs actual %x\n",
1290 			       mr_status.sig_err.err_type,
1291 			       (unsigned long long)*sector,
1292 			       mr_status.sig_err.expected,
1293 			       mr_status.sig_err.actual);
1294 
1295 			switch (mr_status.sig_err.err_type) {
1296 			case IB_SIG_BAD_GUARD:
1297 				return 0x1;
1298 			case IB_SIG_BAD_REFTAG:
1299 				return 0x3;
1300 			case IB_SIG_BAD_APPTAG:
1301 				return 0x2;
1302 			}
1303 		}
1304 	}
1305 
1306 	return 0;
1307 err:
1308 	/* Not alot we can do here, return ambiguous guard error */
1309 	return 0x1;
1310 }
1311