1 /*
2  * iSCSI Initiator over iSER Data-Path
3  *
4  * Copyright (C) 2004 Dmitry Yusupov
5  * Copyright (C) 2004 Alex Aizman
6  * Copyright (C) 2005 Mike Christie
7  * Copyright (c) 2005, 2006 Voltaire, Inc. All rights reserved.
8  * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
9  * maintained by openib-general@openib.org
10  *
11  * This software is available to you under a choice of one of two
12  * licenses.  You may choose to be licensed under the terms of the GNU
13  * General Public License (GPL) Version 2, available from the file
14  * COPYING in the main directory of this source tree, or the
15  * OpenIB.org BSD license below:
16  *
17  *     Redistribution and use in source and binary forms, with or
18  *     without modification, are permitted provided that the following
19  *     conditions are met:
20  *
21  *	- Redistributions of source code must retain the above
22  *	  copyright notice, this list of conditions and the following
23  *	  disclaimer.
24  *
25  *	- Redistributions in binary form must reproduce the above
26  *	  copyright notice, this list of conditions and the following
27  *	  disclaimer in the documentation and/or other materials
28  *	  provided with the distribution.
29  *
30  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
31  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
32  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
33  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
34  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
35  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
36  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
37  * SOFTWARE.
38  *
39  * Credits:
40  *	Christoph Hellwig
41  *	FUJITA Tomonori
42  *	Arne Redlich
43  *	Zhenyu Wang
44  * Modified by:
45  *      Erez Zilber
46  */
47 
48 #include <linux/types.h>
49 #include <linux/list.h>
50 #include <linux/hardirq.h>
51 #include <linux/kfifo.h>
52 #include <linux/blkdev.h>
53 #include <linux/init.h>
54 #include <linux/ioctl.h>
55 #include <linux/cdev.h>
56 #include <linux/in.h>
57 #include <linux/net.h>
58 #include <linux/scatterlist.h>
59 #include <linux/delay.h>
60 #include <linux/slab.h>
61 #include <linux/module.h>
62 
63 #include <net/sock.h>
64 
65 #include <linux/uaccess.h>
66 
67 #include <scsi/scsi_cmnd.h>
68 #include <scsi/scsi_device.h>
69 #include <scsi/scsi_eh.h>
70 #include <scsi/scsi_tcq.h>
71 #include <scsi/scsi_host.h>
72 #include <scsi/scsi.h>
73 #include <scsi/scsi_transport_iscsi.h>
74 
75 #include "iscsi_iser.h"
76 
77 MODULE_DESCRIPTION("iSER (iSCSI Extensions for RDMA) Datamover");
78 MODULE_LICENSE("Dual BSD/GPL");
79 MODULE_AUTHOR("Alex Nezhinsky, Dan Bar Dov, Or Gerlitz");
80 
81 static struct scsi_host_template iscsi_iser_sht;
82 static struct iscsi_transport iscsi_iser_transport;
83 static struct scsi_transport_template *iscsi_iser_scsi_transport;
84 static struct workqueue_struct *release_wq;
85 static DEFINE_MUTEX(unbind_iser_conn_mutex);
86 struct iser_global ig;
87 
88 int iser_debug_level = 0;
89 module_param_named(debug_level, iser_debug_level, int, S_IRUGO | S_IWUSR);
90 MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:disabled)");
91 
92 static unsigned int iscsi_max_lun = 512;
93 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
94 MODULE_PARM_DESC(max_lun, "Max LUNs to allow per session (default:512");
95 
96 unsigned int iser_max_sectors = ISER_DEF_MAX_SECTORS;
97 module_param_named(max_sectors, iser_max_sectors, uint, S_IRUGO | S_IWUSR);
98 MODULE_PARM_DESC(max_sectors, "Max number of sectors in a single scsi command (default:1024");
99 
100 bool iser_always_reg = true;
101 module_param_named(always_register, iser_always_reg, bool, S_IRUGO);
102 MODULE_PARM_DESC(always_register,
103 		 "Always register memory, even for continuous memory regions (default:true)");
104 
105 bool iser_pi_enable = false;
106 module_param_named(pi_enable, iser_pi_enable, bool, S_IRUGO);
107 MODULE_PARM_DESC(pi_enable, "Enable T10-PI offload support (default:disabled)");
108 
109 int iser_pi_guard;
110 module_param_named(pi_guard, iser_pi_guard, int, S_IRUGO);
111 MODULE_PARM_DESC(pi_guard, "T10-PI guard_type [deprecated]");
112 
113 /*
114  * iscsi_iser_recv() - Process a successful recv completion
115  * @conn:         iscsi connection
116  * @hdr:          iscsi header
117  * @rx_data:      buffer containing receive data payload
118  * @rx_data_len:  length of rx_data
119  *
120  * Notes: In case of data length errors or iscsi PDU completion failures
121  *        this routine will signal iscsi layer of connection failure.
122  */
123 void
124 iscsi_iser_recv(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
125 		char *rx_data, int rx_data_len)
126 {
127 	int rc = 0;
128 	int datalen;
129 
130 	/* verify PDU length */
131 	datalen = ntoh24(hdr->dlength);
132 	if (datalen > rx_data_len || (datalen + 4) < rx_data_len) {
133 		iser_err("wrong datalen %d (hdr), %d (IB)\n",
134 			datalen, rx_data_len);
135 		rc = ISCSI_ERR_DATALEN;
136 		goto error;
137 	}
138 
139 	if (datalen != rx_data_len)
140 		iser_dbg("aligned datalen (%d) hdr, %d (IB)\n",
141 			datalen, rx_data_len);
142 
143 	rc = iscsi_complete_pdu(conn, hdr, rx_data, rx_data_len);
144 	if (rc && rc != ISCSI_ERR_NO_SCSI_CMD)
145 		goto error;
146 
147 	return;
148 error:
149 	iscsi_conn_failure(conn, rc);
150 }
151 
152 /**
153  * iscsi_iser_pdu_alloc() - allocate an iscsi-iser PDU
154  * @task:     iscsi task
155  * @opcode:   iscsi command opcode
156  *
157  * Netes: This routine can't fail, just assign iscsi task
158  *        hdr and max hdr size.
159  */
160 static int
161 iscsi_iser_pdu_alloc(struct iscsi_task *task, uint8_t opcode)
162 {
163 	struct iscsi_iser_task *iser_task = task->dd_data;
164 
165 	task->hdr = (struct iscsi_hdr *)&iser_task->desc.iscsi_header;
166 	task->hdr_max = sizeof(iser_task->desc.iscsi_header);
167 
168 	return 0;
169 }
170 
171 /**
172  * iser_initialize_task_headers() - Initialize task headers
173  * @task:       iscsi task
174  * @tx_desc:    iser tx descriptor
175  *
176  * Notes:
177  * This routine may race with iser teardown flow for scsi
178  * error handling TMFs. So for TMF we should acquire the
179  * state mutex to avoid dereferencing the IB device which
180  * may have already been terminated.
181  */
182 int
183 iser_initialize_task_headers(struct iscsi_task *task,
184 			     struct iser_tx_desc *tx_desc)
185 {
186 	struct iser_conn *iser_conn = task->conn->dd_data;
187 	struct iser_device *device = iser_conn->ib_conn.device;
188 	struct iscsi_iser_task *iser_task = task->dd_data;
189 	u64 dma_addr;
190 	const bool mgmt_task = !task->sc && !in_interrupt();
191 	int ret = 0;
192 
193 	if (unlikely(mgmt_task))
194 		mutex_lock(&iser_conn->state_mutex);
195 
196 	if (unlikely(iser_conn->state != ISER_CONN_UP)) {
197 		ret = -ENODEV;
198 		goto out;
199 	}
200 
201 	dma_addr = ib_dma_map_single(device->ib_device, (void *)tx_desc,
202 				ISER_HEADERS_LEN, DMA_TO_DEVICE);
203 	if (ib_dma_mapping_error(device->ib_device, dma_addr)) {
204 		ret = -ENOMEM;
205 		goto out;
206 	}
207 
208 	tx_desc->inv_wr.next = NULL;
209 	tx_desc->reg_wr.wr.next = NULL;
210 	tx_desc->mapped = true;
211 	tx_desc->dma_addr = dma_addr;
212 	tx_desc->tx_sg[0].addr   = tx_desc->dma_addr;
213 	tx_desc->tx_sg[0].length = ISER_HEADERS_LEN;
214 	tx_desc->tx_sg[0].lkey   = device->pd->local_dma_lkey;
215 
216 	iser_task->iser_conn = iser_conn;
217 out:
218 	if (unlikely(mgmt_task))
219 		mutex_unlock(&iser_conn->state_mutex);
220 
221 	return ret;
222 }
223 
224 /**
225  * iscsi_iser_task_init() - Initialize iscsi-iser task
226  * @task: iscsi task
227  *
228  * Initialize the task for the scsi command or mgmt command.
229  *
230  * Return: Returns zero on success or -ENOMEM when failing
231  *         to init task headers (dma mapping error).
232  */
233 static int
234 iscsi_iser_task_init(struct iscsi_task *task)
235 {
236 	struct iscsi_iser_task *iser_task = task->dd_data;
237 	int ret;
238 
239 	ret = iser_initialize_task_headers(task, &iser_task->desc);
240 	if (ret) {
241 		iser_err("Failed to init task %p, err = %d\n",
242 			 iser_task, ret);
243 		return ret;
244 	}
245 
246 	/* mgmt task */
247 	if (!task->sc)
248 		return 0;
249 
250 	iser_task->command_sent = 0;
251 	iser_task_rdma_init(iser_task);
252 	iser_task->sc = task->sc;
253 
254 	return 0;
255 }
256 
257 /**
258  * iscsi_iser_mtask_xmit() - xmit management (immediate) task
259  * @conn: iscsi connection
260  * @task: task management task
261  *
262  * Notes:
263  *	The function can return -EAGAIN in which case caller must
264  *	call it again later, or recover. '0' return code means successful
265  *	xmit.
266  *
267  **/
268 static int
269 iscsi_iser_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
270 {
271 	int error = 0;
272 
273 	iser_dbg("mtask xmit [cid %d itt 0x%x]\n", conn->id, task->itt);
274 
275 	error = iser_send_control(conn, task);
276 
277 	/* since iser xmits control with zero copy, tasks can not be recycled
278 	 * right after sending them.
279 	 * The recycling scheme is based on whether a response is expected
280 	 * - if yes, the task is recycled at iscsi_complete_pdu
281 	 * - if no,  the task is recycled at iser_snd_completion
282 	 */
283 	return error;
284 }
285 
286 static int
287 iscsi_iser_task_xmit_unsol_data(struct iscsi_conn *conn,
288 				 struct iscsi_task *task)
289 {
290 	struct iscsi_r2t_info *r2t = &task->unsol_r2t;
291 	struct iscsi_data hdr;
292 	int error = 0;
293 
294 	/* Send data-out PDUs while there's still unsolicited data to send */
295 	while (iscsi_task_has_unsol_data(task)) {
296 		iscsi_prep_data_out_pdu(task, r2t, &hdr);
297 		iser_dbg("Sending data-out: itt 0x%x, data count %d\n",
298 			   hdr.itt, r2t->data_count);
299 
300 		/* the buffer description has been passed with the command */
301 		/* Send the command */
302 		error = iser_send_data_out(conn, task, &hdr);
303 		if (error) {
304 			r2t->datasn--;
305 			goto iscsi_iser_task_xmit_unsol_data_exit;
306 		}
307 		r2t->sent += r2t->data_count;
308 		iser_dbg("Need to send %d more as data-out PDUs\n",
309 			   r2t->data_length - r2t->sent);
310 	}
311 
312 iscsi_iser_task_xmit_unsol_data_exit:
313 	return error;
314 }
315 
316 /**
317  * iscsi_iser_task_xmit() - xmit iscsi-iser task
318  * @task: iscsi task
319  *
320  * Return: zero on success or escalates $error on failure.
321  */
322 static int
323 iscsi_iser_task_xmit(struct iscsi_task *task)
324 {
325 	struct iscsi_conn *conn = task->conn;
326 	struct iscsi_iser_task *iser_task = task->dd_data;
327 	int error = 0;
328 
329 	if (!task->sc)
330 		return iscsi_iser_mtask_xmit(conn, task);
331 
332 	if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
333 		BUG_ON(scsi_bufflen(task->sc) == 0);
334 
335 		iser_dbg("cmd [itt %x total %d imm %d unsol_data %d\n",
336 			   task->itt, scsi_bufflen(task->sc),
337 			   task->imm_count, task->unsol_r2t.data_length);
338 	}
339 
340 	iser_dbg("ctask xmit [cid %d itt 0x%x]\n",
341 		   conn->id, task->itt);
342 
343 	/* Send the cmd PDU */
344 	if (!iser_task->command_sent) {
345 		error = iser_send_command(conn, task);
346 		if (error)
347 			goto iscsi_iser_task_xmit_exit;
348 		iser_task->command_sent = 1;
349 	}
350 
351 	/* Send unsolicited data-out PDU(s) if necessary */
352 	if (iscsi_task_has_unsol_data(task))
353 		error = iscsi_iser_task_xmit_unsol_data(conn, task);
354 
355  iscsi_iser_task_xmit_exit:
356 	return error;
357 }
358 
359 /**
360  * iscsi_iser_cleanup_task() - cleanup an iscsi-iser task
361  * @task: iscsi task
362  *
363  * Notes: In case the RDMA device is already NULL (might have
364  *        been removed in DEVICE_REMOVAL CM event it will bail-out
365  *        without doing dma unmapping.
366  */
367 static void iscsi_iser_cleanup_task(struct iscsi_task *task)
368 {
369 	struct iscsi_iser_task *iser_task = task->dd_data;
370 	struct iser_tx_desc *tx_desc = &iser_task->desc;
371 	struct iser_conn *iser_conn = task->conn->dd_data;
372 	struct iser_device *device = iser_conn->ib_conn.device;
373 
374 	/* DEVICE_REMOVAL event might have already released the device */
375 	if (!device)
376 		return;
377 
378 	if (likely(tx_desc->mapped)) {
379 		ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
380 				    ISER_HEADERS_LEN, DMA_TO_DEVICE);
381 		tx_desc->mapped = false;
382 	}
383 
384 	/* mgmt tasks do not need special cleanup */
385 	if (!task->sc)
386 		return;
387 
388 	if (iser_task->status == ISER_TASK_STATUS_STARTED) {
389 		iser_task->status = ISER_TASK_STATUS_COMPLETED;
390 		iser_task_rdma_finalize(iser_task);
391 	}
392 }
393 
394 /**
395  * iscsi_iser_check_protection() - check protection information status of task.
396  * @task:     iscsi task
397  * @sector:   error sector if exsists (output)
398  *
399  * Return: zero if no data-integrity errors have occured
400  *         0x1: data-integrity error occured in the guard-block
401  *         0x2: data-integrity error occured in the reference tag
402  *         0x3: data-integrity error occured in the application tag
403  *
404  *         In addition the error sector is marked.
405  */
406 static u8
407 iscsi_iser_check_protection(struct iscsi_task *task, sector_t *sector)
408 {
409 	struct iscsi_iser_task *iser_task = task->dd_data;
410 	enum iser_data_dir dir = iser_task->dir[ISER_DIR_IN] ?
411 					ISER_DIR_IN : ISER_DIR_OUT;
412 
413 	return iser_check_task_pi_status(iser_task, dir, sector);
414 }
415 
416 /**
417  * iscsi_iser_conn_create() - create a new iscsi-iser connection
418  * @cls_session: iscsi class connection
419  * @conn_idx:    connection index within the session (for MCS)
420  *
421  * Return: iscsi_cls_conn when iscsi_conn_setup succeeds or NULL
422  *         otherwise.
423  */
424 static struct iscsi_cls_conn *
425 iscsi_iser_conn_create(struct iscsi_cls_session *cls_session,
426 		       uint32_t conn_idx)
427 {
428 	struct iscsi_conn *conn;
429 	struct iscsi_cls_conn *cls_conn;
430 
431 	cls_conn = iscsi_conn_setup(cls_session, 0, conn_idx);
432 	if (!cls_conn)
433 		return NULL;
434 	conn = cls_conn->dd_data;
435 
436 	/*
437 	 * due to issues with the login code re iser sematics
438 	 * this not set in iscsi_conn_setup - FIXME
439 	 */
440 	conn->max_recv_dlength = ISER_RECV_DATA_SEG_LEN;
441 
442 	return cls_conn;
443 }
444 
445 /**
446  * iscsi_iser_conn_bind() - bind iscsi and iser connection structures
447  * @cls_session:     iscsi class session
448  * @cls_conn:        iscsi class connection
449  * @transport_eph:   transport end-point handle
450  * @is_leading:      indicate if this is the session leading connection (MCS)
451  *
452  * Return: zero on success, $error if iscsi_conn_bind fails and
453  *         -EINVAL in case end-point doesn't exsits anymore or iser connection
454  *         state is not UP (teardown already started).
455  */
456 static int
457 iscsi_iser_conn_bind(struct iscsi_cls_session *cls_session,
458 		     struct iscsi_cls_conn *cls_conn,
459 		     uint64_t transport_eph,
460 		     int is_leading)
461 {
462 	struct iscsi_conn *conn = cls_conn->dd_data;
463 	struct iser_conn *iser_conn;
464 	struct iscsi_endpoint *ep;
465 	int error;
466 
467 	error = iscsi_conn_bind(cls_session, cls_conn, is_leading);
468 	if (error)
469 		return error;
470 
471 	/* the transport ep handle comes from user space so it must be
472 	 * verified against the global ib connections list */
473 	ep = iscsi_lookup_endpoint(transport_eph);
474 	if (!ep) {
475 		iser_err("can't bind eph %llx\n",
476 			 (unsigned long long)transport_eph);
477 		return -EINVAL;
478 	}
479 	iser_conn = ep->dd_data;
480 
481 	mutex_lock(&iser_conn->state_mutex);
482 	if (iser_conn->state != ISER_CONN_UP) {
483 		error = -EINVAL;
484 		iser_err("iser_conn %p state is %d, teardown started\n",
485 			 iser_conn, iser_conn->state);
486 		goto out;
487 	}
488 
489 	error = iser_alloc_rx_descriptors(iser_conn, conn->session);
490 	if (error)
491 		goto out;
492 
493 	/* binds the iSER connection retrieved from the previously
494 	 * connected ep_handle to the iSCSI layer connection. exchanges
495 	 * connection pointers */
496 	iser_info("binding iscsi conn %p to iser_conn %p\n", conn, iser_conn);
497 
498 	conn->dd_data = iser_conn;
499 	iser_conn->iscsi_conn = conn;
500 
501 out:
502 	mutex_unlock(&iser_conn->state_mutex);
503 	return error;
504 }
505 
506 /**
507  * iscsi_iser_conn_start() - start iscsi-iser connection
508  * @cls_conn: iscsi class connection
509  *
510  * Notes: Here iser intialize (or re-initialize) stop_completion as
511  *        from this point iscsi must call conn_stop in session/connection
512  *        teardown so iser transport must wait for it.
513  */
514 static int
515 iscsi_iser_conn_start(struct iscsi_cls_conn *cls_conn)
516 {
517 	struct iscsi_conn *iscsi_conn;
518 	struct iser_conn *iser_conn;
519 
520 	iscsi_conn = cls_conn->dd_data;
521 	iser_conn = iscsi_conn->dd_data;
522 	reinit_completion(&iser_conn->stop_completion);
523 
524 	return iscsi_conn_start(cls_conn);
525 }
526 
527 /**
528  * iscsi_iser_conn_stop() - stop iscsi-iser connection
529  * @cls_conn:  iscsi class connection
530  * @flag:      indicate if recover or terminate (passed as is)
531  *
532  * Notes: Calling iscsi_conn_stop might theoretically race with
533  *        DEVICE_REMOVAL event and dereference a previously freed RDMA device
534  *        handle, so we call it under iser the state lock to protect against
535  *        this kind of race.
536  */
537 static void
538 iscsi_iser_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
539 {
540 	struct iscsi_conn *conn = cls_conn->dd_data;
541 	struct iser_conn *iser_conn = conn->dd_data;
542 
543 	iser_info("stopping iscsi_conn: %p, iser_conn: %p\n", conn, iser_conn);
544 
545 	/*
546 	 * Userspace may have goofed up and not bound the connection or
547 	 * might have only partially setup the connection.
548 	 */
549 	if (iser_conn) {
550 		mutex_lock(&iser_conn->state_mutex);
551 		mutex_lock(&unbind_iser_conn_mutex);
552 		iser_conn_terminate(iser_conn);
553 		iscsi_conn_stop(cls_conn, flag);
554 
555 		/* unbind */
556 		iser_conn->iscsi_conn = NULL;
557 		conn->dd_data = NULL;
558 		mutex_unlock(&unbind_iser_conn_mutex);
559 
560 		complete(&iser_conn->stop_completion);
561 		mutex_unlock(&iser_conn->state_mutex);
562 	} else {
563 		iscsi_conn_stop(cls_conn, flag);
564 	}
565 }
566 
567 /**
568  * iscsi_iser_session_destroy() - destroy iscsi-iser session
569  * @cls_session: iscsi class session
570  *
571  * Removes and free iscsi host.
572  */
573 static void
574 iscsi_iser_session_destroy(struct iscsi_cls_session *cls_session)
575 {
576 	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
577 
578 	iscsi_session_teardown(cls_session);
579 	iscsi_host_remove(shost);
580 	iscsi_host_free(shost);
581 }
582 
583 static inline unsigned int
584 iser_dif_prot_caps(int prot_caps)
585 {
586 	return ((prot_caps & IB_PROT_T10DIF_TYPE_1) ?
587 		SHOST_DIF_TYPE1_PROTECTION | SHOST_DIX_TYPE0_PROTECTION |
588 		SHOST_DIX_TYPE1_PROTECTION : 0) |
589 	       ((prot_caps & IB_PROT_T10DIF_TYPE_2) ?
590 		SHOST_DIF_TYPE2_PROTECTION | SHOST_DIX_TYPE2_PROTECTION : 0) |
591 	       ((prot_caps & IB_PROT_T10DIF_TYPE_3) ?
592 		SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE3_PROTECTION : 0);
593 }
594 
595 /**
596  * iscsi_iser_session_create() - create an iscsi-iser session
597  * @ep:             iscsi end-point handle
598  * @cmds_max:       maximum commands in this session
599  * @qdepth:         session command queue depth
600  * @initial_cmdsn:  initiator command sequnce number
601  *
602  * Allocates and adds a scsi host, expose DIF supprot if
603  * exists, and sets up an iscsi session.
604  */
605 static struct iscsi_cls_session *
606 iscsi_iser_session_create(struct iscsi_endpoint *ep,
607 			  uint16_t cmds_max, uint16_t qdepth,
608 			  uint32_t initial_cmdsn)
609 {
610 	struct iscsi_cls_session *cls_session;
611 	struct Scsi_Host *shost;
612 	struct iser_conn *iser_conn = NULL;
613 	struct ib_conn *ib_conn;
614 	struct ib_device *ib_dev;
615 	u32 max_fr_sectors;
616 
617 	shost = iscsi_host_alloc(&iscsi_iser_sht, 0, 0);
618 	if (!shost)
619 		return NULL;
620 	shost->transportt = iscsi_iser_scsi_transport;
621 	shost->cmd_per_lun = qdepth;
622 	shost->max_lun = iscsi_max_lun;
623 	shost->max_id = 0;
624 	shost->max_channel = 0;
625 	shost->max_cmd_len = 16;
626 
627 	/*
628 	 * older userspace tools (before 2.0-870) did not pass us
629 	 * the leading conn's ep so this will be NULL;
630 	 */
631 	if (ep) {
632 		iser_conn = ep->dd_data;
633 		shost->sg_tablesize = iser_conn->scsi_sg_tablesize;
634 		shost->can_queue = min_t(u16, cmds_max, iser_conn->max_cmds);
635 
636 		mutex_lock(&iser_conn->state_mutex);
637 		if (iser_conn->state != ISER_CONN_UP) {
638 			iser_err("iser conn %p already started teardown\n",
639 				 iser_conn);
640 			mutex_unlock(&iser_conn->state_mutex);
641 			goto free_host;
642 		}
643 
644 		ib_conn = &iser_conn->ib_conn;
645 		ib_dev = ib_conn->device->ib_device;
646 		if (ib_conn->pi_support) {
647 			u32 sig_caps = ib_dev->attrs.sig_prot_cap;
648 
649 			shost->sg_prot_tablesize = shost->sg_tablesize;
650 			scsi_host_set_prot(shost, iser_dif_prot_caps(sig_caps));
651 			scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP |
652 						   SHOST_DIX_GUARD_CRC);
653 		}
654 
655 		if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG))
656 			shost->virt_boundary_mask = SZ_4K - 1;
657 
658 		if (iscsi_host_add(shost, ib_dev->dev.parent)) {
659 			mutex_unlock(&iser_conn->state_mutex);
660 			goto free_host;
661 		}
662 		mutex_unlock(&iser_conn->state_mutex);
663 	} else {
664 		shost->can_queue = min_t(u16, cmds_max, ISER_DEF_XMIT_CMDS_MAX);
665 		if (iscsi_host_add(shost, NULL))
666 			goto free_host;
667 	}
668 
669 	max_fr_sectors = (shost->sg_tablesize * PAGE_SIZE) >> 9;
670 	shost->max_sectors = min(iser_max_sectors, max_fr_sectors);
671 
672 	iser_dbg("iser_conn %p, sg_tablesize %u, max_sectors %u\n",
673 		 iser_conn, shost->sg_tablesize,
674 		 shost->max_sectors);
675 
676 	if (shost->max_sectors < iser_max_sectors)
677 		iser_warn("max_sectors was reduced from %u to %u\n",
678 			  iser_max_sectors, shost->max_sectors);
679 
680 	cls_session = iscsi_session_setup(&iscsi_iser_transport, shost,
681 					  shost->can_queue, 0,
682 					  sizeof(struct iscsi_iser_task),
683 					  initial_cmdsn, 0);
684 	if (!cls_session)
685 		goto remove_host;
686 
687 	return cls_session;
688 
689 remove_host:
690 	iscsi_host_remove(shost);
691 free_host:
692 	iscsi_host_free(shost);
693 	return NULL;
694 }
695 
696 static int
697 iscsi_iser_set_param(struct iscsi_cls_conn *cls_conn,
698 		     enum iscsi_param param, char *buf, int buflen)
699 {
700 	int value;
701 
702 	switch (param) {
703 	case ISCSI_PARAM_MAX_RECV_DLENGTH:
704 		/* TBD */
705 		break;
706 	case ISCSI_PARAM_HDRDGST_EN:
707 		sscanf(buf, "%d", &value);
708 		if (value) {
709 			iser_err("DataDigest wasn't negotiated to None\n");
710 			return -EPROTO;
711 		}
712 		break;
713 	case ISCSI_PARAM_DATADGST_EN:
714 		sscanf(buf, "%d", &value);
715 		if (value) {
716 			iser_err("DataDigest wasn't negotiated to None\n");
717 			return -EPROTO;
718 		}
719 		break;
720 	case ISCSI_PARAM_IFMARKER_EN:
721 		sscanf(buf, "%d", &value);
722 		if (value) {
723 			iser_err("IFMarker wasn't negotiated to No\n");
724 			return -EPROTO;
725 		}
726 		break;
727 	case ISCSI_PARAM_OFMARKER_EN:
728 		sscanf(buf, "%d", &value);
729 		if (value) {
730 			iser_err("OFMarker wasn't negotiated to No\n");
731 			return -EPROTO;
732 		}
733 		break;
734 	default:
735 		return iscsi_set_param(cls_conn, param, buf, buflen);
736 	}
737 
738 	return 0;
739 }
740 
741 /**
742  * iscsi_iser_set_param() - set class connection parameter
743  * @cls_conn:    iscsi class connection
744  * @stats:       iscsi stats to output
745  *
746  * Output connection statistics.
747  */
748 static void
749 iscsi_iser_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
750 {
751 	struct iscsi_conn *conn = cls_conn->dd_data;
752 
753 	stats->txdata_octets = conn->txdata_octets;
754 	stats->rxdata_octets = conn->rxdata_octets;
755 	stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
756 	stats->dataout_pdus = conn->dataout_pdus_cnt;
757 	stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
758 	stats->datain_pdus = conn->datain_pdus_cnt; /* always 0 */
759 	stats->r2t_pdus = conn->r2t_pdus_cnt; /* always 0 */
760 	stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
761 	stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
762 	stats->custom_length = 0;
763 }
764 
765 static int iscsi_iser_get_ep_param(struct iscsi_endpoint *ep,
766 				   enum iscsi_param param, char *buf)
767 {
768 	struct iser_conn *iser_conn = ep->dd_data;
769 
770 	switch (param) {
771 	case ISCSI_PARAM_CONN_PORT:
772 	case ISCSI_PARAM_CONN_ADDRESS:
773 		if (!iser_conn || !iser_conn->ib_conn.cma_id)
774 			return -ENOTCONN;
775 
776 		return iscsi_conn_get_addr_param((struct sockaddr_storage *)
777 				&iser_conn->ib_conn.cma_id->route.addr.dst_addr,
778 				param, buf);
779 	default:
780 		break;
781 	}
782 	return -ENOSYS;
783 }
784 
785 /**
786  * iscsi_iser_ep_connect() - Initiate iSER connection establishment
787  * @shost:          scsi_host
788  * @dst_addr:       destination address
789  * @non_blocking:   indicate if routine can block
790  *
791  * Allocate an iscsi endpoint, an iser_conn structure and bind them.
792  * After that start RDMA connection establishment via rdma_cm. We
793  * don't allocate iser_conn embedded in iscsi_endpoint since in teardown
794  * the endpoint will be destroyed at ep_disconnect while iser_conn will
795  * cleanup its resources asynchronuously.
796  *
797  * Return: iscsi_endpoint created by iscsi layer or ERR_PTR(error)
798  *         if fails.
799  */
800 static struct iscsi_endpoint *
801 iscsi_iser_ep_connect(struct Scsi_Host *shost, struct sockaddr *dst_addr,
802 		      int non_blocking)
803 {
804 	int err;
805 	struct iser_conn *iser_conn;
806 	struct iscsi_endpoint *ep;
807 
808 	ep = iscsi_create_endpoint(0);
809 	if (!ep)
810 		return ERR_PTR(-ENOMEM);
811 
812 	iser_conn = kzalloc(sizeof(*iser_conn), GFP_KERNEL);
813 	if (!iser_conn) {
814 		err = -ENOMEM;
815 		goto failure;
816 	}
817 
818 	ep->dd_data = iser_conn;
819 	iser_conn->ep = ep;
820 	iser_conn_init(iser_conn);
821 
822 	err = iser_connect(iser_conn, NULL, dst_addr, non_blocking);
823 	if (err)
824 		goto failure;
825 
826 	return ep;
827 failure:
828 	iscsi_destroy_endpoint(ep);
829 	return ERR_PTR(err);
830 }
831 
832 /**
833  * iscsi_iser_ep_poll() - poll for iser connection establishment to complete
834  * @ep:            iscsi endpoint (created at ep_connect)
835  * @timeout_ms:    polling timeout allowed in ms.
836  *
837  * This routine boils down to waiting for up_completion signaling
838  * that cma_id got CONNECTED event.
839  *
840  * Return: 1 if succeeded in connection establishment, 0 if timeout expired
841  *         (libiscsi will retry will kick in) or -1 if interrupted by signal
842  *         or more likely iser connection state transitioned to TEMINATING or
843  *         DOWN during the wait period.
844  */
845 static int
846 iscsi_iser_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
847 {
848 	struct iser_conn *iser_conn = ep->dd_data;
849 	int rc;
850 
851 	rc = wait_for_completion_interruptible_timeout(&iser_conn->up_completion,
852 						       msecs_to_jiffies(timeout_ms));
853 	/* if conn establishment failed, return error code to iscsi */
854 	if (rc == 0) {
855 		mutex_lock(&iser_conn->state_mutex);
856 		if (iser_conn->state == ISER_CONN_TERMINATING ||
857 		    iser_conn->state == ISER_CONN_DOWN)
858 			rc = -1;
859 		mutex_unlock(&iser_conn->state_mutex);
860 	}
861 
862 	iser_info("iser conn %p rc = %d\n", iser_conn, rc);
863 
864 	if (rc > 0)
865 		return 1; /* success, this is the equivalent of EPOLLOUT */
866 	else if (!rc)
867 		return 0; /* timeout */
868 	else
869 		return rc; /* signal */
870 }
871 
872 /**
873  * iscsi_iser_ep_disconnect() - Initiate connection teardown process
874  * @ep:    iscsi endpoint handle
875  *
876  * This routine is not blocked by iser and RDMA termination process
877  * completion as we queue a deffered work for iser/RDMA destruction
878  * and cleanup or actually call it immediately in case we didn't pass
879  * iscsi conn bind/start stage, thus it is safe.
880  */
881 static void
882 iscsi_iser_ep_disconnect(struct iscsi_endpoint *ep)
883 {
884 	struct iser_conn *iser_conn = ep->dd_data;
885 
886 	iser_info("ep %p iser conn %p\n", ep, iser_conn);
887 
888 	mutex_lock(&iser_conn->state_mutex);
889 	iser_conn_terminate(iser_conn);
890 
891 	/*
892 	 * if iser_conn and iscsi_conn are bound, we must wait for
893 	 * iscsi_conn_stop and flush errors completion before freeing
894 	 * the iser resources. Otherwise we are safe to free resources
895 	 * immediately.
896 	 */
897 	if (iser_conn->iscsi_conn) {
898 		INIT_WORK(&iser_conn->release_work, iser_release_work);
899 		queue_work(release_wq, &iser_conn->release_work);
900 		mutex_unlock(&iser_conn->state_mutex);
901 	} else {
902 		iser_conn->state = ISER_CONN_DOWN;
903 		mutex_unlock(&iser_conn->state_mutex);
904 		iser_conn_release(iser_conn);
905 	}
906 
907 	iscsi_destroy_endpoint(ep);
908 }
909 
910 static umode_t iser_attr_is_visible(int param_type, int param)
911 {
912 	switch (param_type) {
913 	case ISCSI_HOST_PARAM:
914 		switch (param) {
915 		case ISCSI_HOST_PARAM_NETDEV_NAME:
916 		case ISCSI_HOST_PARAM_HWADDRESS:
917 		case ISCSI_HOST_PARAM_INITIATOR_NAME:
918 			return S_IRUGO;
919 		default:
920 			return 0;
921 		}
922 	case ISCSI_PARAM:
923 		switch (param) {
924 		case ISCSI_PARAM_MAX_RECV_DLENGTH:
925 		case ISCSI_PARAM_MAX_XMIT_DLENGTH:
926 		case ISCSI_PARAM_HDRDGST_EN:
927 		case ISCSI_PARAM_DATADGST_EN:
928 		case ISCSI_PARAM_CONN_ADDRESS:
929 		case ISCSI_PARAM_CONN_PORT:
930 		case ISCSI_PARAM_EXP_STATSN:
931 		case ISCSI_PARAM_PERSISTENT_ADDRESS:
932 		case ISCSI_PARAM_PERSISTENT_PORT:
933 		case ISCSI_PARAM_PING_TMO:
934 		case ISCSI_PARAM_RECV_TMO:
935 		case ISCSI_PARAM_INITIAL_R2T_EN:
936 		case ISCSI_PARAM_MAX_R2T:
937 		case ISCSI_PARAM_IMM_DATA_EN:
938 		case ISCSI_PARAM_FIRST_BURST:
939 		case ISCSI_PARAM_MAX_BURST:
940 		case ISCSI_PARAM_PDU_INORDER_EN:
941 		case ISCSI_PARAM_DATASEQ_INORDER_EN:
942 		case ISCSI_PARAM_TARGET_NAME:
943 		case ISCSI_PARAM_TPGT:
944 		case ISCSI_PARAM_USERNAME:
945 		case ISCSI_PARAM_PASSWORD:
946 		case ISCSI_PARAM_USERNAME_IN:
947 		case ISCSI_PARAM_PASSWORD_IN:
948 		case ISCSI_PARAM_FAST_ABORT:
949 		case ISCSI_PARAM_ABORT_TMO:
950 		case ISCSI_PARAM_LU_RESET_TMO:
951 		case ISCSI_PARAM_TGT_RESET_TMO:
952 		case ISCSI_PARAM_IFACE_NAME:
953 		case ISCSI_PARAM_INITIATOR_NAME:
954 		case ISCSI_PARAM_DISCOVERY_SESS:
955 			return S_IRUGO;
956 		default:
957 			return 0;
958 		}
959 	}
960 
961 	return 0;
962 }
963 
964 static struct scsi_host_template iscsi_iser_sht = {
965 	.module                 = THIS_MODULE,
966 	.name                   = "iSCSI Initiator over iSER",
967 	.queuecommand           = iscsi_queuecommand,
968 	.change_queue_depth	= scsi_change_queue_depth,
969 	.sg_tablesize           = ISCSI_ISER_DEF_SG_TABLESIZE,
970 	.cmd_per_lun            = ISER_DEF_CMD_PER_LUN,
971 	.eh_timed_out		= iscsi_eh_cmd_timed_out,
972 	.eh_abort_handler       = iscsi_eh_abort,
973 	.eh_device_reset_handler= iscsi_eh_device_reset,
974 	.eh_target_reset_handler = iscsi_eh_recover_target,
975 	.target_alloc		= iscsi_target_alloc,
976 	.proc_name              = "iscsi_iser",
977 	.this_id                = -1,
978 	.track_queue_depth	= 1,
979 };
980 
981 static struct iscsi_transport iscsi_iser_transport = {
982 	.owner                  = THIS_MODULE,
983 	.name                   = "iser",
984 	.caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_TEXT_NEGO,
985 	/* session management */
986 	.create_session         = iscsi_iser_session_create,
987 	.destroy_session        = iscsi_iser_session_destroy,
988 	/* connection management */
989 	.create_conn            = iscsi_iser_conn_create,
990 	.bind_conn              = iscsi_iser_conn_bind,
991 	.destroy_conn           = iscsi_conn_teardown,
992 	.attr_is_visible	= iser_attr_is_visible,
993 	.set_param              = iscsi_iser_set_param,
994 	.get_conn_param		= iscsi_conn_get_param,
995 	.get_ep_param		= iscsi_iser_get_ep_param,
996 	.get_session_param	= iscsi_session_get_param,
997 	.start_conn             = iscsi_iser_conn_start,
998 	.stop_conn              = iscsi_iser_conn_stop,
999 	/* iscsi host params */
1000 	.get_host_param		= iscsi_host_get_param,
1001 	.set_host_param		= iscsi_host_set_param,
1002 	/* IO */
1003 	.send_pdu		= iscsi_conn_send_pdu,
1004 	.get_stats		= iscsi_iser_conn_get_stats,
1005 	.init_task		= iscsi_iser_task_init,
1006 	.xmit_task		= iscsi_iser_task_xmit,
1007 	.cleanup_task		= iscsi_iser_cleanup_task,
1008 	.alloc_pdu		= iscsi_iser_pdu_alloc,
1009 	.check_protection	= iscsi_iser_check_protection,
1010 	/* recovery */
1011 	.session_recovery_timedout = iscsi_session_recovery_timedout,
1012 
1013 	.ep_connect             = iscsi_iser_ep_connect,
1014 	.ep_poll                = iscsi_iser_ep_poll,
1015 	.ep_disconnect          = iscsi_iser_ep_disconnect
1016 };
1017 
1018 static int __init iser_init(void)
1019 {
1020 	int err;
1021 
1022 	iser_dbg("Starting iSER datamover...\n");
1023 
1024 	if (iscsi_max_lun < 1) {
1025 		iser_err("Invalid max_lun value of %u\n", iscsi_max_lun);
1026 		return -EINVAL;
1027 	}
1028 
1029 	memset(&ig, 0, sizeof(struct iser_global));
1030 
1031 	ig.desc_cache = kmem_cache_create("iser_descriptors",
1032 					  sizeof(struct iser_tx_desc),
1033 					  0, SLAB_HWCACHE_ALIGN,
1034 					  NULL);
1035 	if (ig.desc_cache == NULL)
1036 		return -ENOMEM;
1037 
1038 	/* device init is called only after the first addr resolution */
1039 	mutex_init(&ig.device_list_mutex);
1040 	INIT_LIST_HEAD(&ig.device_list);
1041 	mutex_init(&ig.connlist_mutex);
1042 	INIT_LIST_HEAD(&ig.connlist);
1043 
1044 	release_wq = alloc_workqueue("release workqueue", 0, 0);
1045 	if (!release_wq) {
1046 		iser_err("failed to allocate release workqueue\n");
1047 		err = -ENOMEM;
1048 		goto err_alloc_wq;
1049 	}
1050 
1051 	iscsi_iser_scsi_transport = iscsi_register_transport(
1052 							&iscsi_iser_transport);
1053 	if (!iscsi_iser_scsi_transport) {
1054 		iser_err("iscsi_register_transport failed\n");
1055 		err = -EINVAL;
1056 		goto err_reg;
1057 	}
1058 
1059 	return 0;
1060 
1061 err_reg:
1062 	destroy_workqueue(release_wq);
1063 err_alloc_wq:
1064 	kmem_cache_destroy(ig.desc_cache);
1065 
1066 	return err;
1067 }
1068 
1069 static void __exit iser_exit(void)
1070 {
1071 	struct iser_conn *iser_conn, *n;
1072 	int connlist_empty;
1073 
1074 	iser_dbg("Removing iSER datamover...\n");
1075 	destroy_workqueue(release_wq);
1076 
1077 	mutex_lock(&ig.connlist_mutex);
1078 	connlist_empty = list_empty(&ig.connlist);
1079 	mutex_unlock(&ig.connlist_mutex);
1080 
1081 	if (!connlist_empty) {
1082 		iser_err("Error cleanup stage completed but we still have iser "
1083 			 "connections, destroying them anyway\n");
1084 		list_for_each_entry_safe(iser_conn, n, &ig.connlist,
1085 					 conn_list) {
1086 			iser_conn_release(iser_conn);
1087 		}
1088 	}
1089 
1090 	iscsi_unregister_transport(&iscsi_iser_transport);
1091 	kmem_cache_destroy(ig.desc_cache);
1092 }
1093 
1094 module_init(iser_init);
1095 module_exit(iser_exit);
1096