1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
23  *
24  * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
25  */
26 
27 #include <sys/cpuvar.h>
28 #include <sys/types.h>
29 #include <sys/conf.h>
30 #include <sys/stat.h>
31 #include <sys/file.h>
32 #include <sys/ddi.h>
33 #include <sys/sunddi.h>
34 #include <sys/modctl.h>
35 #include <sys/sysmacros.h>
36 #include <sys/socket.h>
37 #include <sys/strsubr.h>
38 #include <sys/nvpair.h>
39 
40 #include <sys/stmf.h>
41 #include <sys/stmf_ioctl.h>
42 #include <sys/portif.h>
43 #include <sys/idm/idm.h>
44 #include <sys/idm/idm_conn_sm.h>
45 
46 #include "iscsit_isns.h"
47 #include "iscsit.h"
48 
49 #define	ISCSIT_VERSION		BUILD_DATE "-1.18dev"
50 #define	ISCSIT_NAME_VERSION	"COMSTAR ISCSIT v" ISCSIT_VERSION
51 
52 /*
53  * DDI entry points.
54  */
55 static int iscsit_drv_attach(dev_info_t *, ddi_attach_cmd_t);
56 static int iscsit_drv_detach(dev_info_t *, ddi_detach_cmd_t);
57 static int iscsit_drv_getinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
58 static int iscsit_drv_open(dev_t *, int, int, cred_t *);
59 static int iscsit_drv_close(dev_t, int, int, cred_t *);
60 static boolean_t iscsit_drv_busy(void);
61 static int iscsit_drv_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);
62 
63 extern struct mod_ops mod_miscops;
64 
65 
66 static struct cb_ops iscsit_cb_ops = {
67 	iscsit_drv_open,	/* cb_open */
68 	iscsit_drv_close,	/* cb_close */
69 	nodev,			/* cb_strategy */
70 	nodev,			/* cb_print */
71 	nodev,			/* cb_dump */
72 	nodev,			/* cb_read */
73 	nodev,			/* cb_write */
74 	iscsit_drv_ioctl,	/* cb_ioctl */
75 	nodev,			/* cb_devmap */
76 	nodev,			/* cb_mmap */
77 	nodev,			/* cb_segmap */
78 	nochpoll,		/* cb_chpoll */
79 	ddi_prop_op,		/* cb_prop_op */
80 	NULL,			/* cb_streamtab */
81 	D_MP,			/* cb_flag */
82 	CB_REV,			/* cb_rev */
83 	nodev,			/* cb_aread */
84 	nodev,			/* cb_awrite */
85 };
86 
87 static struct dev_ops iscsit_dev_ops = {
88 	DEVO_REV,		/* devo_rev */
89 	0,			/* devo_refcnt */
90 	iscsit_drv_getinfo,	/* devo_getinfo */
91 	nulldev,		/* devo_identify */
92 	nulldev,		/* devo_probe */
93 	iscsit_drv_attach,	/* devo_attach */
94 	iscsit_drv_detach,	/* devo_detach */
95 	nodev,			/* devo_reset */
96 	&iscsit_cb_ops,		/* devo_cb_ops */
97 	NULL,			/* devo_bus_ops */
98 	NULL,			/* devo_power */
99 	ddi_quiesce_not_needed,	/* quiesce */
100 };
101 
102 static struct modldrv modldrv = {
103 	&mod_driverops,
104 	"iSCSI Target",
105 	&iscsit_dev_ops,
106 };
107 
108 static struct modlinkage modlinkage = {
109 	MODREV_1,
110 	&modldrv,
111 	NULL,
112 };
113 
114 
115 iscsit_global_t iscsit_global;
116 
117 kmem_cache_t	*iscsit_status_pdu_cache;
118 
119 boolean_t	iscsit_sm_logging = B_FALSE;
120 
121 kmutex_t	login_sm_session_mutex;
122 
123 static idm_status_t iscsit_init(dev_info_t *dip);
124 static idm_status_t iscsit_enable_svc(iscsit_hostinfo_t *hostinfo);
125 static void iscsit_disable_svc(void);
126 
127 static int
128 iscsit_check_cmdsn_and_queue(idm_pdu_t *rx_pdu);
129 
130 static void
131 iscsit_add_pdu_to_queue(iscsit_sess_t *ist, idm_pdu_t *rx_pdu);
132 
133 static idm_pdu_t *
134 iscsit_remove_pdu_from_queue(iscsit_sess_t *ist, uint32_t cmdsn);
135 
136 static void
137 iscsit_process_pdu_in_queue(iscsit_sess_t *ist);
138 
139 static void
140 iscsit_rxpdu_queue_monitor_session(iscsit_sess_t *ist);
141 
142 static void
143 iscsit_rxpdu_queue_monitor(void *arg);
144 
145 static void
146 iscsit_post_staged_pdu(idm_pdu_t *rx_pdu);
147 
148 static void
149 iscsit_post_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu);
150 
151 static void
152 iscsit_op_scsi_task_mgmt(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
153 
154 static void
155 iscsit_pdu_op_noop(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
156 
157 static void
158 iscsit_pdu_op_login_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
159 
160 void
161 iscsit_pdu_op_text_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
162 
163 static void
164 iscsit_pdu_op_logout_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
165 
166 int iscsit_cmd_window();
167 
168 static  int
169 iscsit_sna_lt(uint32_t sn1, uint32_t sn2);
170 
171 void
172 iscsit_set_cmdsn(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
173 
174 static void
175 iscsit_deferred_dispatch(idm_pdu_t *rx_pdu);
176 
177 static void
178 iscsit_deferred(void *rx_pdu_void);
179 
180 static idm_status_t
181 iscsit_conn_accept(idm_conn_t *ic);
182 
183 static idm_status_t
184 iscsit_ffp_enabled(idm_conn_t *ic);
185 
186 static idm_status_t
187 iscsit_ffp_disabled(idm_conn_t *ic, idm_ffp_disable_t disable_class);
188 
189 static idm_status_t
190 iscsit_conn_lost(idm_conn_t *ic);
191 
192 static idm_status_t
193 iscsit_conn_destroy(idm_conn_t *ic);
194 
195 static stmf_data_buf_t *
196 iscsit_dbuf_alloc(scsi_task_t *task, uint32_t size, uint32_t *pminsize,
197     uint32_t flags);
198 
199 static void
200 iscsit_dbuf_free(stmf_dbuf_store_t *ds, stmf_data_buf_t *dbuf);
201 
202 static void
203 iscsit_buf_xfer_cb(idm_buf_t *idb, idm_status_t status);
204 
205 static void
206 iscsit_send_good_status_done(idm_pdu_t *pdu, idm_status_t status);
207 
208 static void
209 iscsit_send_status_done(idm_pdu_t *pdu, idm_status_t status);
210 
211 static stmf_status_t
212 iscsit_idm_to_stmf(idm_status_t idmrc);
213 
214 static iscsit_task_t *
215 iscsit_task_alloc(iscsit_conn_t *ict);
216 
217 static void
218 iscsit_task_free(iscsit_task_t *itask);
219 
220 static iscsit_task_t *
221 iscsit_tm_task_alloc(iscsit_conn_t *ict);
222 
223 static void
224 iscsit_tm_task_free(iscsit_task_t *itask);
225 
226 static idm_status_t
227 iscsit_task_start(iscsit_task_t *itask);
228 
229 static void
230 iscsit_task_done(iscsit_task_t *itask);
231 
232 static int
233 iscsit_status_pdu_constructor(void *pdu_void, void *arg, int flags);
234 
235 static void
236 iscsit_pp_cb(struct stmf_port_provider *pp, int cmd, void *arg, uint32_t flags);
237 
238 static it_cfg_status_t
239 iscsit_config_merge(it_config_t *cfg);
240 
241 static idm_status_t
242 iscsit_login_fail(idm_conn_t *ic);
243 
244 static boolean_t iscsit_cmdsn_in_window(iscsit_conn_t *ict, uint32_t cmdsn);
245 static void iscsit_send_direct_scsi_resp(iscsit_conn_t *ict, idm_pdu_t *rx_pdu,
246     uint8_t response, uint8_t cmd_status);
247 static void iscsit_send_task_mgmt_resp(idm_pdu_t *tm_resp_pdu,
248     uint8_t tm_status);
249 
250 /*
251  * MC/S: Out-of-order commands are staged on a session-wide wait
252  * queue until a system-tunable threshold is reached. A separate
253  * thread is used to scan the staging queue on all the session,
254  * If a delayed PDU does not arrive within a timeout, the target
255  * will advance to the staged PDU that is next in sequence, skipping
256  * over the missing PDU(s) to go past a hole in the sequence.
257  */
258 volatile int rxpdu_queue_threshold = ISCSIT_RXPDU_QUEUE_THRESHOLD;
259 
260 static kmutex_t		iscsit_rxpdu_queue_monitor_mutex;
261 kthread_t		*iscsit_rxpdu_queue_monitor_thr_id;
262 static kt_did_t		iscsit_rxpdu_queue_monitor_thr_did;
263 static boolean_t	iscsit_rxpdu_queue_monitor_thr_running;
264 static kcondvar_t	iscsit_rxpdu_queue_monitor_cv;
265 
266 int
267 _init(void)
268 {
269 	int rc;
270 
271 	rw_init(&iscsit_global.global_rwlock, NULL, RW_DRIVER, NULL);
272 	mutex_init(&iscsit_global.global_state_mutex, NULL,
273 	    MUTEX_DRIVER, NULL);
274 	iscsit_global.global_svc_state = ISE_DETACHED;
275 
276 	mutex_init(&iscsit_rxpdu_queue_monitor_mutex, NULL,
277 	    MUTEX_DRIVER, NULL);
278 	mutex_init(&login_sm_session_mutex, NULL, MUTEX_DRIVER, NULL);
279 	iscsit_rxpdu_queue_monitor_thr_id = NULL;
280 	iscsit_rxpdu_queue_monitor_thr_running = B_FALSE;
281 	cv_init(&iscsit_rxpdu_queue_monitor_cv, NULL, CV_DEFAULT, NULL);
282 
283 	if ((rc = mod_install(&modlinkage)) != 0) {
284 		mutex_destroy(&iscsit_global.global_state_mutex);
285 		rw_destroy(&iscsit_global.global_rwlock);
286 		return (rc);
287 	}
288 
289 	return (rc);
290 }
291 
292 int
293 _info(struct modinfo *modinfop)
294 {
295 	return (mod_info(&modlinkage, modinfop));
296 }
297 
298 int
299 _fini(void)
300 {
301 	int rc;
302 
303 	rc = mod_remove(&modlinkage);
304 
305 	if (rc == 0) {
306 		mutex_destroy(&iscsit_rxpdu_queue_monitor_mutex);
307 		mutex_destroy(&login_sm_session_mutex);
308 		cv_destroy(&iscsit_rxpdu_queue_monitor_cv);
309 		mutex_destroy(&iscsit_global.global_state_mutex);
310 		rw_destroy(&iscsit_global.global_rwlock);
311 	}
312 
313 	return (rc);
314 }
315 
316 /*
317  * DDI entry points.
318  */
319 
320 /* ARGSUSED */
321 static int
322 iscsit_drv_getinfo(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg,
323     void **result)
324 {
325 	ulong_t instance = getminor((dev_t)arg);
326 
327 	switch (cmd) {
328 	case DDI_INFO_DEVT2DEVINFO:
329 		*result = iscsit_global.global_dip;
330 		return (DDI_SUCCESS);
331 
332 	case DDI_INFO_DEVT2INSTANCE:
333 		*result = (void *)instance;
334 		return (DDI_SUCCESS);
335 
336 	default:
337 		break;
338 	}
339 
340 	return (DDI_FAILURE);
341 }
342 
343 static int
344 iscsit_drv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
345 {
346 	if (cmd != DDI_ATTACH) {
347 		return (DDI_FAILURE);
348 	}
349 
350 	if (ddi_get_instance(dip) != 0) {
351 		/* we only allow instance 0 to attach */
352 		return (DDI_FAILURE);
353 	}
354 
355 	/* create the minor node */
356 	if (ddi_create_minor_node(dip, ISCSIT_MODNAME, S_IFCHR, 0,
357 	    DDI_PSEUDO, 0) != DDI_SUCCESS) {
358 		cmn_err(CE_WARN, "iscsit_drv_attach: "
359 		    "failed creating minor node");
360 		return (DDI_FAILURE);
361 	}
362 
363 	if (iscsit_init(dip) != IDM_STATUS_SUCCESS) {
364 		cmn_err(CE_WARN, "iscsit_drv_attach: "
365 		    "failed to initialize");
366 		ddi_remove_minor_node(dip, NULL);
367 		return (DDI_FAILURE);
368 	}
369 
370 	iscsit_global.global_svc_state = ISE_DISABLED;
371 	iscsit_global.global_dip = dip;
372 
373 	return (DDI_SUCCESS);
374 }
375 
376 /*ARGSUSED*/
377 static int
378 iscsit_drv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
379 {
380 	if (cmd != DDI_DETACH)
381 		return (DDI_FAILURE);
382 
383 	/*
384 	 * drv_detach is called in a context that owns the
385 	 * device node for the /dev/pseudo device.  If this thread blocks
386 	 * for any resource, other threads that need the /dev/pseudo device
387 	 * may end up in a deadlock with this thread.Hence, we use a
388 	 * separate lock just for the structures that drv_detach needs
389 	 * to access.
390 	 */
391 	mutex_enter(&iscsit_global.global_state_mutex);
392 	if (iscsit_drv_busy()) {
393 		mutex_exit(&iscsit_global.global_state_mutex);
394 		return (EBUSY);
395 	}
396 
397 	iscsit_global.global_dip = NULL;
398 	ddi_remove_minor_node(dip, NULL);
399 
400 	ldi_ident_release(iscsit_global.global_li);
401 	iscsit_global.global_svc_state = ISE_DETACHED;
402 
403 	mutex_exit(&iscsit_global.global_state_mutex);
404 
405 	return (DDI_SUCCESS);
406 }
407 
408 /*ARGSUSED*/
409 static int
410 iscsit_drv_open(dev_t *devp, int flag, int otyp, cred_t *credp)
411 {
412 	return (0);
413 }
414 
415 /* ARGSUSED */
416 static int
417 iscsit_drv_close(dev_t dev, int flag, int otyp, cred_t *credp)
418 {
419 	return (0);
420 }
421 
422 static boolean_t
423 iscsit_drv_busy(void)
424 {
425 	ASSERT(MUTEX_HELD(&iscsit_global.global_state_mutex));
426 
427 	switch (iscsit_global.global_svc_state) {
428 	case ISE_DISABLED:
429 	case ISE_DETACHED:
430 		return (B_FALSE);
431 	default:
432 		return (B_TRUE);
433 	}
434 	/* NOTREACHED */
435 }
436 
437 /* ARGSUSED */
438 static int
439 iscsit_drv_ioctl(dev_t drv, int cmd, intptr_t argp, int flag, cred_t *cred,
440     int *retval)
441 {
442 	iscsit_ioc_set_config_t		setcfg;
443 	iscsit_ioc_set_config32_t	setcfg32;
444 	char				*cfg_pnvlist = NULL;
445 	nvlist_t			*cfg_nvlist = NULL;
446 	it_config_t			*cfg = NULL;
447 	idm_status_t			idmrc;
448 	int				rc = 0;
449 
450 	if (drv_priv(cred) != 0) {
451 		return (EPERM);
452 	}
453 
454 	mutex_enter(&iscsit_global.global_state_mutex);
455 
456 	/*
457 	 * Validate ioctl requests against global service state
458 	 */
459 	switch (iscsit_global.global_svc_state) {
460 	case ISE_ENABLED:
461 		if (cmd == ISCSIT_IOC_DISABLE_SVC) {
462 			iscsit_global.global_svc_state = ISE_DISABLING;
463 		} else if (cmd == ISCSIT_IOC_ENABLE_SVC) {
464 			/* Already enabled */
465 			mutex_exit(&iscsit_global.global_state_mutex);
466 			return (0);
467 		} else {
468 			iscsit_global.global_svc_state = ISE_BUSY;
469 		}
470 		break;
471 	case ISE_DISABLED:
472 		if (cmd == ISCSIT_IOC_ENABLE_SVC) {
473 			iscsit_global.global_svc_state = ISE_ENABLING;
474 		} else if (cmd == ISCSIT_IOC_DISABLE_SVC) {
475 			/* Already disabled */
476 			mutex_exit(&iscsit_global.global_state_mutex);
477 			return (0);
478 		} else {
479 			rc = EFAULT;
480 		}
481 		break;
482 	case ISE_BUSY:
483 	case ISE_ENABLING:
484 	case ISE_DISABLING:
485 		rc = EAGAIN;
486 		break;
487 	case ISE_DETACHED:
488 	default:
489 		rc = EFAULT;
490 		break;
491 	}
492 
493 	mutex_exit(&iscsit_global.global_state_mutex);
494 	if (rc != 0)
495 		return (rc);
496 
497 	/* Handle ioctl request (enable/disable have already been handled) */
498 	switch (cmd) {
499 	case ISCSIT_IOC_SET_CONFIG:
500 		/* Any errors must set state back to ISE_ENABLED */
501 		switch (ddi_model_convert_from(flag & FMODELS)) {
502 		case DDI_MODEL_ILP32:
503 			if (ddi_copyin((void *)argp, &setcfg32,
504 			    sizeof (iscsit_ioc_set_config32_t), flag) != 0) {
505 				rc = EFAULT;
506 				goto cleanup;
507 			}
508 
509 			setcfg.set_cfg_pnvlist =
510 			    (char *)((uintptr_t)setcfg32.set_cfg_pnvlist);
511 			setcfg.set_cfg_vers = setcfg32.set_cfg_vers;
512 			setcfg.set_cfg_pnvlist_len =
513 			    setcfg32.set_cfg_pnvlist_len;
514 			break;
515 		case DDI_MODEL_NONE:
516 			if (ddi_copyin((void *)argp, &setcfg,
517 			    sizeof (iscsit_ioc_set_config_t), flag) != 0) {
518 				rc = EFAULT;
519 				goto cleanup;
520 			}
521 			break;
522 		default:
523 			rc = EFAULT;
524 			goto cleanup;
525 		}
526 
527 		/* Check API version */
528 		if (setcfg.set_cfg_vers != ISCSIT_API_VERS0) {
529 			rc = EINVAL;
530 			goto cleanup;
531 		}
532 
533 		/* Config is in packed nvlist format so unpack it */
534 		cfg_pnvlist = kmem_alloc(setcfg.set_cfg_pnvlist_len,
535 		    KM_SLEEP);
536 		ASSERT(cfg_pnvlist != NULL);
537 
538 		if (ddi_copyin(setcfg.set_cfg_pnvlist, cfg_pnvlist,
539 		    setcfg.set_cfg_pnvlist_len, flag) != 0) {
540 			rc = EFAULT;
541 			goto cleanup;
542 		}
543 
544 		rc = nvlist_unpack(cfg_pnvlist, setcfg.set_cfg_pnvlist_len,
545 		    &cfg_nvlist, KM_SLEEP);
546 		if (rc != 0) {
547 			goto cleanup;
548 		}
549 
550 		/* Translate nvlist */
551 		rc = it_nv_to_config(cfg_nvlist, &cfg);
552 		if (rc != 0) {
553 			cmn_err(CE_WARN, "Configuration is invalid");
554 			goto cleanup;
555 		}
556 
557 		/* Update config */
558 		rc = iscsit_config_merge(cfg);
559 		/* FALLTHROUGH */
560 
561 cleanup:
562 		if (cfg)
563 			it_config_free_cmn(cfg);
564 		if (cfg_pnvlist)
565 			kmem_free(cfg_pnvlist, setcfg.set_cfg_pnvlist_len);
566 		if (cfg_nvlist)
567 			nvlist_free(cfg_nvlist);
568 
569 		/*
570 		 * Now that the reconfig is complete set our state back to
571 		 * enabled.
572 		 */
573 		mutex_enter(&iscsit_global.global_state_mutex);
574 		iscsit_global.global_svc_state = ISE_ENABLED;
575 		mutex_exit(&iscsit_global.global_state_mutex);
576 		break;
577 	case ISCSIT_IOC_ENABLE_SVC: {
578 		iscsit_hostinfo_t hostinfo;
579 
580 		if (ddi_copyin((void *)argp, &hostinfo.length,
581 		    sizeof (hostinfo.length), flag) != 0) {
582 			mutex_enter(&iscsit_global.global_state_mutex);
583 			iscsit_global.global_svc_state = ISE_DISABLED;
584 			mutex_exit(&iscsit_global.global_state_mutex);
585 			return (EFAULT);
586 		}
587 
588 		if (hostinfo.length > sizeof (hostinfo.fqhn))
589 			hostinfo.length = sizeof (hostinfo.fqhn);
590 
591 		if (ddi_copyin((void *)((caddr_t)argp +
592 		    sizeof (hostinfo.length)), &hostinfo.fqhn,
593 		    hostinfo.length, flag) != 0) {
594 			mutex_enter(&iscsit_global.global_state_mutex);
595 			iscsit_global.global_svc_state = ISE_DISABLED;
596 			mutex_exit(&iscsit_global.global_state_mutex);
597 			return (EFAULT);
598 		}
599 
600 		idmrc = iscsit_enable_svc(&hostinfo);
601 		mutex_enter(&iscsit_global.global_state_mutex);
602 		if (idmrc == IDM_STATUS_SUCCESS) {
603 			iscsit_global.global_svc_state = ISE_ENABLED;
604 		} else {
605 			rc = EIO;
606 			iscsit_global.global_svc_state = ISE_DISABLED;
607 		}
608 		mutex_exit(&iscsit_global.global_state_mutex);
609 		break;
610 	}
611 	case ISCSIT_IOC_DISABLE_SVC:
612 		iscsit_disable_svc();
613 		mutex_enter(&iscsit_global.global_state_mutex);
614 		iscsit_global.global_svc_state = ISE_DISABLED;
615 		mutex_exit(&iscsit_global.global_state_mutex);
616 		break;
617 
618 	default:
619 		rc = EINVAL;
620 		mutex_enter(&iscsit_global.global_state_mutex);
621 		iscsit_global.global_svc_state = ISE_ENABLED;
622 		mutex_exit(&iscsit_global.global_state_mutex);
623 	}
624 
625 	return (rc);
626 }
627 
628 static idm_status_t
629 iscsit_init(dev_info_t *dip)
630 {
631 	int			rc;
632 
633 	rc = ldi_ident_from_dip(dip, &iscsit_global.global_li);
634 	ASSERT(rc == 0);  /* Failure indicates invalid argument */
635 
636 	iscsit_global.global_svc_state = ISE_DISABLED;
637 
638 	return (IDM_STATUS_SUCCESS);
639 }
640 
641 /*
642  * iscsit_enable_svc
643  *
644  * registers all the configured targets and target portals with STMF
645  */
646 static idm_status_t
647 iscsit_enable_svc(iscsit_hostinfo_t *hostinfo)
648 {
649 	stmf_port_provider_t	*pp;
650 	stmf_dbuf_store_t	*dbuf_store;
651 	boolean_t		did_iscsit_isns_init;
652 	idm_status_t		retval = IDM_STATUS_SUCCESS;
653 
654 	ASSERT(iscsit_global.global_svc_state == ISE_ENABLING);
655 
656 	/*
657 	 * Make sure that can tell if we have partially allocated
658 	 * in case we need to exit and tear down anything allocated.
659 	 */
660 	iscsit_global.global_tsih_pool = NULL;
661 	iscsit_global.global_dbuf_store = NULL;
662 	iscsit_status_pdu_cache = NULL;
663 	pp = NULL;
664 	iscsit_global.global_pp = NULL;
665 	iscsit_global.global_default_tpg = NULL;
666 	did_iscsit_isns_init = B_FALSE;
667 	iscsit_global.global_dispatch_taskq = NULL;
668 
669 	/* Setup remaining fields in iscsit_global_t */
670 	idm_refcnt_init(&iscsit_global.global_refcnt,
671 	    &iscsit_global);
672 
673 	avl_create(&iscsit_global.global_discovery_sessions,
674 	    iscsit_sess_avl_compare, sizeof (iscsit_sess_t),
675 	    offsetof(iscsit_sess_t, ist_tgt_ln));
676 
677 	avl_create(&iscsit_global.global_target_list,
678 	    iscsit_tgt_avl_compare, sizeof (iscsit_tgt_t),
679 	    offsetof(iscsit_tgt_t, target_global_ln));
680 
681 	list_create(&iscsit_global.global_deleted_target_list,
682 	    sizeof (iscsit_tgt_t),
683 	    offsetof(iscsit_tgt_t, target_global_deleted_ln));
684 
685 	avl_create(&iscsit_global.global_tpg_list,
686 	    iscsit_tpg_avl_compare, sizeof (iscsit_tpg_t),
687 	    offsetof(iscsit_tpg_t, tpg_global_ln));
688 
689 	avl_create(&iscsit_global.global_ini_list,
690 	    iscsit_ini_avl_compare, sizeof (iscsit_ini_t),
691 	    offsetof(iscsit_ini_t, ini_global_ln));
692 
693 	iscsit_global.global_tsih_pool = vmem_create("iscsit_tsih_pool",
694 	    (void *)1, ISCSI_MAX_TSIH, 1, NULL, NULL, NULL, 0,
695 	    VM_SLEEP | VMC_IDENTIFIER);
696 
697 	/*
698 	 * Setup STMF dbuf store.  Our buffers are bound to a specific
699 	 * connection so we really can't let STMF cache buffers for us.
700 	 * Consequently we'll just allocate one global buffer store.
701 	 */
702 	dbuf_store = stmf_alloc(STMF_STRUCT_DBUF_STORE, 0, 0);
703 	if (dbuf_store == NULL) {
704 		retval = IDM_STATUS_FAIL;
705 		goto tear_down_and_return;
706 	}
707 	dbuf_store->ds_alloc_data_buf = iscsit_dbuf_alloc;
708 	dbuf_store->ds_free_data_buf = iscsit_dbuf_free;
709 	dbuf_store->ds_port_private = NULL;
710 	iscsit_global.global_dbuf_store = dbuf_store;
711 
712 	/* Status PDU cache */
713 	iscsit_status_pdu_cache = kmem_cache_create("iscsit_status_pdu_cache",
714 	    sizeof (idm_pdu_t) + sizeof (iscsi_scsi_rsp_hdr_t), 8,
715 	    &iscsit_status_pdu_constructor,
716 	    NULL, NULL, NULL, NULL, KM_SLEEP);
717 
718 	/* Default TPG and portal */
719 	iscsit_global.global_default_tpg = iscsit_tpg_createdefault();
720 	if (iscsit_global.global_default_tpg == NULL) {
721 		retval = IDM_STATUS_FAIL;
722 		goto tear_down_and_return;
723 	}
724 
725 	/* initialize isns client */
726 	(void) iscsit_isns_init(hostinfo);
727 	did_iscsit_isns_init = B_TRUE;
728 
729 	/* Register port provider */
730 	pp = stmf_alloc(STMF_STRUCT_PORT_PROVIDER, 0, 0);
731 	if (pp == NULL) {
732 		retval = IDM_STATUS_FAIL;
733 		goto tear_down_and_return;
734 	}
735 
736 	pp->pp_portif_rev = PORTIF_REV_1;
737 	pp->pp_instance = 0;
738 	pp->pp_name = ISCSIT_MODNAME;
739 	pp->pp_cb = iscsit_pp_cb;
740 
741 	iscsit_global.global_pp = pp;
742 
743 
744 	if (stmf_register_port_provider(pp) != STMF_SUCCESS) {
745 		retval = IDM_STATUS_FAIL;
746 		goto tear_down_and_return;
747 	}
748 
749 	iscsit_global.global_dispatch_taskq = taskq_create("iscsit_dispatch",
750 	    1, minclsyspri, 16, 16, TASKQ_PREPOPULATE);
751 
752 	/* Scan staged PDUs, meaningful in MC/S situations */
753 	iscsit_rxpdu_queue_monitor_start();
754 
755 	return (IDM_STATUS_SUCCESS);
756 
757 tear_down_and_return:
758 
759 	if (iscsit_global.global_dispatch_taskq) {
760 		taskq_destroy(iscsit_global.global_dispatch_taskq);
761 		iscsit_global.global_dispatch_taskq = NULL;
762 	}
763 
764 	if (did_iscsit_isns_init)
765 		iscsit_isns_fini();
766 
767 	if (iscsit_global.global_default_tpg) {
768 		iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);
769 		iscsit_global.global_default_tpg = NULL;
770 	}
771 
772 	if (iscsit_global.global_pp)
773 		iscsit_global.global_pp = NULL;
774 
775 	if (pp)
776 		stmf_free(pp);
777 
778 	if (iscsit_status_pdu_cache) {
779 		kmem_cache_destroy(iscsit_status_pdu_cache);
780 		iscsit_status_pdu_cache = NULL;
781 	}
782 
783 	if (iscsit_global.global_dbuf_store) {
784 		stmf_free(iscsit_global.global_dbuf_store);
785 		iscsit_global.global_dbuf_store = NULL;
786 	}
787 
788 	if (iscsit_global.global_tsih_pool) {
789 		vmem_destroy(iscsit_global.global_tsih_pool);
790 		iscsit_global.global_tsih_pool = NULL;
791 	}
792 
793 	avl_destroy(&iscsit_global.global_ini_list);
794 	avl_destroy(&iscsit_global.global_tpg_list);
795 	list_destroy(&iscsit_global.global_deleted_target_list);
796 	avl_destroy(&iscsit_global.global_target_list);
797 	avl_destroy(&iscsit_global.global_discovery_sessions);
798 
799 	idm_refcnt_destroy(&iscsit_global.global_refcnt);
800 
801 	return (retval);
802 }
803 
804 /*
805  * iscsit_disable_svc
806  *
807  * clean up all existing connections and deregister targets from STMF
808  */
809 static void
810 iscsit_disable_svc(void)
811 {
812 	iscsit_sess_t	*sess;
813 
814 	ASSERT(iscsit_global.global_svc_state == ISE_DISABLING);
815 
816 	iscsit_rxpdu_queue_monitor_stop();
817 
818 	/* tear down discovery sessions */
819 	for (sess = avl_first(&iscsit_global.global_discovery_sessions);
820 	    sess != NULL;
821 	    sess = AVL_NEXT(&iscsit_global.global_discovery_sessions, sess))
822 		iscsit_sess_close(sess);
823 
824 	/*
825 	 * Passing NULL to iscsit_config_merge tells it to go to an empty
826 	 * config.
827 	 */
828 	(void) iscsit_config_merge(NULL);
829 
830 	/*
831 	 * Wait until there are no more global references
832 	 */
833 	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
834 	idm_refcnt_destroy(&iscsit_global.global_refcnt);
835 
836 	/*
837 	 * Default TPG must be destroyed after global_refcnt is 0.
838 	 */
839 	iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);
840 
841 	avl_destroy(&iscsit_global.global_discovery_sessions);
842 	list_destroy(&iscsit_global.global_deleted_target_list);
843 	avl_destroy(&iscsit_global.global_target_list);
844 	avl_destroy(&iscsit_global.global_tpg_list);
845 	avl_destroy(&iscsit_global.global_ini_list);
846 
847 	taskq_destroy(iscsit_global.global_dispatch_taskq);
848 
849 	iscsit_isns_fini();
850 
851 	stmf_free(iscsit_global.global_dbuf_store);
852 	iscsit_global.global_dbuf_store = NULL;
853 
854 	(void) stmf_deregister_port_provider(iscsit_global.global_pp);
855 	stmf_free(iscsit_global.global_pp);
856 	iscsit_global.global_pp = NULL;
857 
858 	kmem_cache_destroy(iscsit_status_pdu_cache);
859 	iscsit_status_pdu_cache = NULL;
860 
861 	vmem_destroy(iscsit_global.global_tsih_pool);
862 	iscsit_global.global_tsih_pool = NULL;
863 }
864 
865 void
866 iscsit_global_hold()
867 {
868 	/*
869 	 * To take out a global hold, we must either own the global
870 	 * state mutex or we must be running inside of an ioctl that
871 	 * has set the global state to ISE_BUSY, ISE_DISABLING, or
872 	 * ISE_ENABLING.  We don't track the "owner" for these flags,
873 	 * so just checking if they are set is enough for now.
874 	 */
875 	ASSERT((iscsit_global.global_svc_state == ISE_ENABLING) ||
876 	    (iscsit_global.global_svc_state == ISE_DISABLING) ||
877 	    (iscsit_global.global_svc_state == ISE_BUSY) ||
878 	    MUTEX_HELD(&iscsit_global.global_state_mutex));
879 
880 	idm_refcnt_hold(&iscsit_global.global_refcnt);
881 }
882 
883 void
884 iscsit_global_rele()
885 {
886 	idm_refcnt_rele(&iscsit_global.global_refcnt);
887 }
888 
889 void
890 iscsit_global_wait_ref()
891 {
892 	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
893 }
894 
895 /*
896  * IDM callbacks
897  */
898 
899 /*ARGSUSED*/
900 void
901 iscsit_rx_pdu(idm_conn_t *ic, idm_pdu_t *rx_pdu)
902 {
903 	iscsit_conn_t *ict = ic->ic_handle;
904 	switch (IDM_PDU_OPCODE(rx_pdu)) {
905 	case ISCSI_OP_SCSI_CMD:
906 		ASSERT(0); /* Shouldn't happen */
907 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
908 		break;
909 	case ISCSI_OP_SNACK_CMD:
910 		/*
911 		 * We'll need to handle this when we support ERL1/2.  For
912 		 * now we treat it as a protocol error.
913 		 */
914 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
915 		idm_conn_event(ic, CE_TRANSPORT_FAIL, NULL);
916 		break;
917 	case ISCSI_OP_SCSI_TASK_MGT_MSG:
918 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
919 			iscsit_set_cmdsn(ict, rx_pdu);
920 			iscsit_op_scsi_task_mgmt(ict, rx_pdu);
921 		}
922 		break;
923 	case ISCSI_OP_NOOP_OUT:
924 	case ISCSI_OP_LOGIN_CMD:
925 	case ISCSI_OP_TEXT_CMD:
926 	case ISCSI_OP_LOGOUT_CMD:
927 		/*
928 		 * If/when we switch to userland processing these PDU's
929 		 * will be handled by iscsitd.
930 		 */
931 		iscsit_deferred_dispatch(rx_pdu);
932 		break;
933 	default:
934 		/* Protocol error */
935 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
936 		idm_conn_event(ic, CE_TRANSPORT_FAIL, NULL);
937 		break;
938 	}
939 }
940 
941 /*ARGSUSED*/
942 void
943 iscsit_rx_pdu_error(idm_conn_t *ic, idm_pdu_t *rx_pdu, idm_status_t status)
944 {
945 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
946 }
947 
948 void
949 iscsit_task_aborted(idm_task_t *idt, idm_status_t status)
950 {
951 	iscsit_task_t *itask = idt->idt_private;
952 
953 	switch (status) {
954 	case IDM_STATUS_SUSPENDED:
955 		break;
956 	case IDM_STATUS_ABORTED:
957 		mutex_enter(&itask->it_mutex);
958 		itask->it_aborted = B_TRUE;
959 		/*
960 		 * We rely on the fact that STMF tracks outstanding
961 		 * buffer transfers and will free all of our buffers
962 		 * before freeing the task so we don't need to
963 		 * explicitly free the buffers from iscsit/idm
964 		 */
965 		if (itask->it_stmf_abort) {
966 			mutex_exit(&itask->it_mutex);
967 			/*
968 			 * Task is no longer active
969 			 */
970 			iscsit_task_done(itask);
971 
972 			/*
973 			 * STMF has already asked for this task to be aborted
974 			 *
975 			 * STMF specification is wrong... says to return
976 			 * STMF_ABORTED, the code actually looks for
977 			 * STMF_ABORT_SUCCESS.
978 			 */
979 			stmf_task_lport_aborted(itask->it_stmf_task,
980 			    STMF_ABORT_SUCCESS, STMF_IOF_LPORT_DONE);
981 			return;
982 		} else {
983 			mutex_exit(&itask->it_mutex);
984 			/*
985 			 * Tell STMF to stop processing the task.
986 			 */
987 			stmf_abort(STMF_QUEUE_TASK_ABORT, itask->it_stmf_task,
988 			    STMF_ABORTED, NULL);
989 			return;
990 		}
991 		/*NOTREACHED*/
992 	default:
993 		ASSERT(0);
994 	}
995 }
996 
997 /*ARGSUSED*/
998 idm_status_t
999 iscsit_client_notify(idm_conn_t *ic, idm_client_notify_t icn,
1000     uintptr_t data)
1001 {
1002 	idm_status_t rc = IDM_STATUS_SUCCESS;
1003 
1004 	/*
1005 	 * IDM client notifications will never occur at interrupt level
1006 	 * since they are generated from the connection state machine which
1007 	 * running on taskq threads.
1008 	 *
1009 	 */
1010 	switch (icn) {
1011 	case CN_CONNECT_ACCEPT:
1012 		rc = iscsit_conn_accept(ic); /* No data */
1013 		break;
1014 	case CN_FFP_ENABLED:
1015 		rc = iscsit_ffp_enabled(ic); /* No data */
1016 		break;
1017 	case CN_FFP_DISABLED:
1018 		/*
1019 		 * Data indicates whether this was the result of an
1020 		 * explicit logout request.
1021 		 */
1022 		rc = iscsit_ffp_disabled(ic, (idm_ffp_disable_t)data);
1023 		break;
1024 	case CN_CONNECT_LOST:
1025 		rc = iscsit_conn_lost(ic);
1026 		break;
1027 	case CN_CONNECT_DESTROY:
1028 		rc = iscsit_conn_destroy(ic);
1029 		break;
1030 	case CN_LOGIN_FAIL:
1031 		/*
1032 		 * Force the login state machine to completion
1033 		 */
1034 		rc = iscsit_login_fail(ic);
1035 		break;
1036 	default:
1037 		rc = IDM_STATUS_REJECT;
1038 		break;
1039 	}
1040 
1041 	return (rc);
1042 }
1043 
1044 /*
1045  * iscsit_update_statsn is invoked for all the PDUs which have the StatSN
1046  * field in the header. The StatSN is incremented if the IDM_PDU_ADVANCE_STATSN
1047  * flag is set in the pdu flags field. The StatSN is connection-wide and is
1048  * protected by the mutex ict_statsn_mutex. For Data-In PDUs, if the flag
1049  * IDM_TASK_PHASECOLLAPSE_REQ is set, the status (phase-collapse) is also filled
1050  */
1051 void
1052 iscsit_update_statsn(idm_task_t *idm_task, idm_pdu_t *pdu)
1053 {
1054 	iscsi_scsi_rsp_hdr_t *rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1055 	iscsit_conn_t *ict = (iscsit_conn_t *)pdu->isp_ic->ic_handle;
1056 	iscsit_task_t *itask = NULL;
1057 	scsi_task_t *task = NULL;
1058 
1059 	mutex_enter(&ict->ict_statsn_mutex);
1060 	rsp->statsn = htonl(ict->ict_statsn);
1061 	if (pdu->isp_flags & IDM_PDU_ADVANCE_STATSN)
1062 		ict->ict_statsn++;
1063 	mutex_exit(&ict->ict_statsn_mutex);
1064 
1065 	/*
1066 	 * The last SCSI Data PDU passed for a command may also contain the
1067 	 * status if the status indicates termination with no expections, i.e.
1068 	 * no sense data or response involved. If the command completes with
1069 	 * an error, then the response and sense data will be sent in a
1070 	 * separate iSCSI Response PDU.
1071 	 */
1072 	if ((idm_task) && (idm_task->idt_flags & IDM_TASK_PHASECOLLAPSE_REQ)) {
1073 		itask = idm_task->idt_private;
1074 		task = itask->it_stmf_task;
1075 
1076 		rsp->cmd_status = task->task_scsi_status;
1077 		rsp->flags	|= ISCSI_FLAG_DATA_STATUS;
1078 		if (task->task_status_ctrl & TASK_SCTRL_OVER) {
1079 			rsp->flags |= ISCSI_FLAG_CMD_OVERFLOW;
1080 		} else if (task->task_status_ctrl & TASK_SCTRL_UNDER) {
1081 			rsp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
1082 		}
1083 		rsp->residual_count = htonl(task->task_resid);
1084 
1085 		/*
1086 		 * Removing the task from the session task list
1087 		 * just before the status is sent in the last
1088 		 * Data PDU transfer
1089 		 */
1090 		iscsit_task_done(itask);
1091 	}
1092 }
1093 
1094 void
1095 iscsit_build_hdr(idm_task_t *idm_task, idm_pdu_t *pdu, uint8_t opcode)
1096 {
1097 	iscsit_task_t *itask = idm_task->idt_private;
1098 	iscsi_data_rsp_hdr_t *dh = (iscsi_data_rsp_hdr_t *)pdu->isp_hdr;
1099 
1100 	/*
1101 	 * We acquired iscsit_sess_t.ist_sn_mutex in iscsit_xfer_scsi_data
1102 	 */
1103 	ASSERT(MUTEX_HELD(&itask->it_ict->ict_sess->ist_sn_mutex));
1104 	/*
1105 	 * On incoming data, the target transfer tag and Lun is only
1106 	 * provided by the target if the A bit is set, Since the target
1107 	 * does not currently support Error Recovery Level 1, the A
1108 	 * bit is never set.
1109 	 */
1110 	dh->opcode = opcode;
1111 	dh->itt = itask->it_itt;
1112 	dh->ttt = ((opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_SCSI_DATA_RSP) ?
1113 	    ISCSI_RSVD_TASK_TAG : itask->it_ttt;
1114 
1115 	dh->expcmdsn = htonl(itask->it_ict->ict_sess->ist_expcmdsn);
1116 	dh->maxcmdsn = htonl(itask->it_ict->ict_sess->ist_maxcmdsn);
1117 
1118 	/*
1119 	 * IDM must set:
1120 	 *
1121 	 * data.flags and rtt.flags
1122 	 * data.dlength
1123 	 * data.datasn
1124 	 * data.offset
1125 	 * statsn, residual_count and cmd_status (for phase collapse)
1126 	 * rtt.rttsn
1127 	 * rtt.data_offset
1128 	 * rtt.data_length
1129 	 */
1130 }
1131 
1132 void
1133 iscsit_keepalive(idm_conn_t *ic)
1134 {
1135 	idm_pdu_t		*nop_in_pdu;
1136 	iscsi_nop_in_hdr_t	*nop_in;
1137 	iscsit_conn_t		*ict = ic->ic_handle;
1138 
1139 	/*
1140 	 * IDM noticed the connection has been idle for too long so it's
1141 	 * time to provoke some activity.  Build and transmit an iSCSI
1142 	 * nop-in PDU -- when the initiator responds it will be counted
1143 	 * as "activity" and keep the connection alive.
1144 	 *
1145 	 * We don't actually care about the response here at the iscsit level
1146 	 * so we will just throw it away without looking at it when it arrives.
1147 	 */
1148 	nop_in_pdu = idm_pdu_alloc(sizeof (*nop_in), 0);
1149 	idm_pdu_init(nop_in_pdu, ic, NULL, NULL);
1150 	nop_in = (iscsi_nop_in_hdr_t *)nop_in_pdu->isp_hdr;
1151 	bzero(nop_in, sizeof (*nop_in));
1152 	nop_in->opcode = ISCSI_OP_NOOP_IN;
1153 	nop_in->flags = ISCSI_FLAG_FINAL;
1154 	nop_in->itt = ISCSI_RSVD_TASK_TAG;
1155 	/*
1156 	 * When the target sends a NOP-In as a Ping, the target transfer tag
1157 	 * is set to a valid (not reserved) value and the initiator task tag
1158 	 * is set to ISCSI_RSVD_TASK_TAG (0xffffffff). In this case the StatSN
1159 	 * will always contain the next sequence number but the StatSN for the
1160 	 * connection is not advanced after this PDU is sent.
1161 	 */
1162 	nop_in_pdu->isp_flags |= IDM_PDU_SET_STATSN;
1163 	/*
1164 	 * This works because we don't currently allocate ttt's anywhere else
1165 	 * in iscsit so as long as we stay out of IDM's range we are safe.
1166 	 * If we need to allocate ttt's for other PDU's in the future this will
1167 	 * need to be improved.
1168 	 */
1169 	mutex_enter(&ict->ict_mutex);
1170 	nop_in->ttt = ict->ict_keepalive_ttt;
1171 	ict->ict_keepalive_ttt++;
1172 	if (ict->ict_keepalive_ttt == ISCSI_RSVD_TASK_TAG)
1173 		ict->ict_keepalive_ttt = IDM_TASKIDS_MAX;
1174 	mutex_exit(&ict->ict_mutex);
1175 
1176 	iscsit_pdu_tx(nop_in_pdu);
1177 }
1178 
1179 static idm_status_t
1180 iscsit_conn_accept(idm_conn_t *ic)
1181 {
1182 	iscsit_conn_t *ict;
1183 
1184 	/*
1185 	 * We need to get a global hold here to ensure that the service
1186 	 * doesn't get shutdown prior to establishing a session. This
1187 	 * gets released in iscsit_conn_destroy().
1188 	 */
1189 	mutex_enter(&iscsit_global.global_state_mutex);
1190 	if (iscsit_global.global_svc_state != ISE_ENABLED) {
1191 		mutex_exit(&iscsit_global.global_state_mutex);
1192 		return (IDM_STATUS_FAIL);
1193 	}
1194 	iscsit_global_hold();
1195 	mutex_exit(&iscsit_global.global_state_mutex);
1196 
1197 	/*
1198 	 * Allocate an associated iscsit structure to represent this
1199 	 * connection.  We shouldn't really create a session until we
1200 	 * get the first login PDU.
1201 	 */
1202 	ict = kmem_zalloc(sizeof (*ict), KM_SLEEP);
1203 
1204 	ict->ict_ic = ic;
1205 	ict->ict_statsn = 1;
1206 	ict->ict_keepalive_ttt = IDM_TASKIDS_MAX; /* Avoid IDM TT range */
1207 	ic->ic_handle = ict;
1208 	mutex_init(&ict->ict_mutex, NULL, MUTEX_DRIVER, NULL);
1209 	mutex_init(&ict->ict_statsn_mutex, NULL, MUTEX_DRIVER, NULL);
1210 	idm_refcnt_init(&ict->ict_refcnt, ict);
1211 
1212 	/*
1213 	 * Initialize login state machine
1214 	 */
1215 	if (iscsit_login_sm_init(ict) != IDM_STATUS_SUCCESS) {
1216 		iscsit_global_rele();
1217 		/*
1218 		 * Cleanup the ict after idm notifies us about this failure
1219 		 */
1220 		return (IDM_STATUS_FAIL);
1221 	}
1222 
1223 	return (IDM_STATUS_SUCCESS);
1224 }
1225 
1226 idm_status_t
1227 iscsit_conn_reinstate(iscsit_conn_t *reinstate_ict, iscsit_conn_t *new_ict)
1228 {
1229 	idm_status_t	result;
1230 
1231 	/*
1232 	 * Note in new connection state that this connection is
1233 	 * reinstating an existing connection.
1234 	 */
1235 	new_ict->ict_reinstating = B_TRUE;
1236 	new_ict->ict_reinstate_conn = reinstate_ict;
1237 	new_ict->ict_statsn = reinstate_ict->ict_statsn;
1238 
1239 	/*
1240 	 * Now generate connection state machine event to existing connection
1241 	 * so that it starts the cleanup process.
1242 	 */
1243 	result = idm_conn_reinstate_event(reinstate_ict->ict_ic,
1244 	    new_ict->ict_ic);
1245 
1246 	return (result);
1247 }
1248 
1249 void
1250 iscsit_conn_hold(iscsit_conn_t *ict)
1251 {
1252 	idm_refcnt_hold(&ict->ict_refcnt);
1253 }
1254 
1255 void
1256 iscsit_conn_rele(iscsit_conn_t *ict)
1257 {
1258 	idm_refcnt_rele(&ict->ict_refcnt);
1259 }
1260 
1261 void
1262 iscsit_conn_dispatch_hold(iscsit_conn_t *ict)
1263 {
1264 	idm_refcnt_hold(&ict->ict_dispatch_refcnt);
1265 }
1266 
1267 void
1268 iscsit_conn_dispatch_rele(iscsit_conn_t *ict)
1269 {
1270 	idm_refcnt_rele(&ict->ict_dispatch_refcnt);
1271 }
1272 
1273 static idm_status_t
1274 iscsit_login_fail(idm_conn_t *ic)
1275 {
1276 	iscsit_conn_t *ict = ic->ic_handle;
1277 
1278 	/* Generate login state machine event */
1279 	iscsit_login_sm_event(ict, ILE_LOGIN_CONN_ERROR, NULL);
1280 
1281 	return (IDM_STATUS_SUCCESS);
1282 }
1283 
1284 static idm_status_t
1285 iscsit_ffp_enabled(idm_conn_t *ic)
1286 {
1287 	iscsit_conn_t *ict = ic->ic_handle;
1288 
1289 	/* Generate session state machine event */
1290 	iscsit_sess_sm_event(ict->ict_sess, SE_CONN_LOGGED_IN, ict);
1291 
1292 	return (IDM_STATUS_SUCCESS);
1293 }
1294 
1295 static idm_status_t
1296 iscsit_ffp_disabled(idm_conn_t *ic, idm_ffp_disable_t disable_class)
1297 {
1298 	iscsit_conn_t *ict = ic->ic_handle;
1299 
1300 	/* Generate session state machine event */
1301 	switch (disable_class) {
1302 	case FD_CONN_FAIL:
1303 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FFP_FAIL, ict);
1304 		break;
1305 	case FD_CONN_LOGOUT:
1306 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FFP_DISABLE, ict);
1307 		break;
1308 	case FD_SESS_LOGOUT:
1309 		iscsit_sess_sm_event(ict->ict_sess, SE_SESSION_CLOSE, ict);
1310 		break;
1311 	default:
1312 		ASSERT(0);
1313 	}
1314 
1315 	return (IDM_STATUS_SUCCESS);
1316 }
1317 
1318 static idm_status_t
1319 iscsit_conn_lost(idm_conn_t *ic)
1320 {
1321 	iscsit_conn_t	*ict	= ic->ic_handle;
1322 	iscsit_sess_t	*ist	= ict->ict_sess;
1323 	iscsit_cbuf_t	*cbuf;
1324 	idm_pdu_t	*rx_pdu;
1325 	int i;
1326 
1327 	mutex_enter(&ict->ict_mutex);
1328 	ict->ict_lost = B_TRUE;
1329 	mutex_exit(&ict->ict_mutex);
1330 	/*
1331 	 * scrub the staging queue for all PDUs on this connection
1332 	 */
1333 	if (ist != NULL) {
1334 		mutex_enter(&ist->ist_sn_mutex);
1335 		for (cbuf = ist->ist_rxpdu_queue, i = 0;
1336 		    ((cbuf->cb_num_elems > 0) && (i < ISCSIT_RXPDU_QUEUE_LEN));
1337 		    i++) {
1338 			if (((rx_pdu = cbuf->cb_buffer[i]) != NULL) &&
1339 			    (rx_pdu->isp_ic == ic)) {
1340 				/* conn is lost, drop the pdu */
1341 				DTRACE_PROBE3(scrubbing__staging__queue,
1342 				    iscsit_sess_t *, ist, idm_conn_t *, ic,
1343 				    idm_pdu_t *, rx_pdu);
1344 				idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
1345 				cbuf->cb_buffer[i] = NULL;
1346 				cbuf->cb_num_elems--;
1347 				iscsit_conn_dispatch_rele(ict);
1348 			}
1349 		}
1350 		mutex_exit(&ist->ist_sn_mutex);
1351 	}
1352 	/*
1353 	 * Make sure there aren't any PDU's transitioning from the receive
1354 	 * handler to the dispatch taskq.
1355 	 */
1356 	idm_refcnt_wait_ref(&ict->ict_dispatch_refcnt);
1357 
1358 	return (IDM_STATUS_SUCCESS);
1359 }
1360 
1361 static idm_status_t
1362 iscsit_conn_destroy(idm_conn_t *ic)
1363 {
1364 	iscsit_conn_t *ict = ic->ic_handle;
1365 
1366 	mutex_enter(&ict->ict_mutex);
1367 	ict->ict_destroyed = B_TRUE;
1368 	mutex_exit(&ict->ict_mutex);
1369 
1370 	/* Generate session state machine event */
1371 	if (ict->ict_sess != NULL) {
1372 		/*
1373 		 * Session state machine will call iscsit_conn_destroy_done()
1374 		 * when it has removed references to this connection.
1375 		 */
1376 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FAIL, ict);
1377 	}
1378 
1379 	idm_refcnt_wait_ref(&ict->ict_refcnt);
1380 	/*
1381 	 * The session state machine does not need to post
1382 	 * events to IDM any longer, so it is safe to set
1383 	 * the idm connection reference to NULL
1384 	 */
1385 	ict->ict_ic = NULL;
1386 
1387 	/* Reap the login state machine */
1388 	iscsit_login_sm_fini(ict);
1389 
1390 	/* Clean up any text command remnants */
1391 	iscsit_text_cmd_fini(ict);
1392 
1393 	mutex_destroy(&ict->ict_mutex);
1394 	idm_refcnt_destroy(&ict->ict_refcnt);
1395 	kmem_free(ict, sizeof (*ict));
1396 
1397 	iscsit_global_rele();
1398 
1399 	return (IDM_STATUS_SUCCESS);
1400 }
1401 
1402 void
1403 iscsit_conn_logout(iscsit_conn_t *ict)
1404 {
1405 	/*
1406 	 * If the iscsi connection is active, then
1407 	 * logout the IDM connection by sending a
1408 	 * CE_LOGOUT_SESSION_SUCCESS, else, no action
1409 	 * needs to be taken because the connection
1410 	 * is already in the teardown process.
1411 	 */
1412 	mutex_enter(&ict->ict_mutex);
1413 	if (ict->ict_lost == B_FALSE && ict->ict_destroyed == B_FALSE) {
1414 		idm_conn_event(ict->ict_ic, CE_LOGOUT_SESSION_SUCCESS, NULL);
1415 	}
1416 	mutex_exit(&ict->ict_mutex);
1417 }
1418 
1419 /*
1420  * STMF-related functions
1421  *
1422  * iSCSI to STMF mapping
1423  *
1424  * Session == ?
1425  * Connection == bound to local port but not itself a local port
1426  * Target
1427  * Target portal (group?) == local port (really but we're not going to do this)
1428  *	iscsit needs to map connections to local ports (whatever we decide
1429  * 	they are)
1430  * Target == ?
1431  */
1432 
1433 /*ARGSUSED*/
1434 static stmf_data_buf_t *
1435 iscsit_dbuf_alloc(scsi_task_t *task, uint32_t size, uint32_t *pminsize,
1436     uint32_t flags)
1437 {
1438 	iscsit_task_t *itask = task->task_port_private;
1439 	idm_buf_t *idm_buffer;
1440 	iscsit_buf_t	*ibuf;
1441 	stmf_data_buf_t *result;
1442 	uint32_t	bsize;
1443 
1444 	/*
1445 	 * If the requested size is larger than MaxBurstLength and the
1446 	 * given pminsize is also larger than MaxBurstLength, then the
1447 	 * allocation fails (dbuf = NULL) and pminsize is modified to
1448 	 * be equal to MaxBurstLength. stmf/sbd then should re-invoke
1449 	 * this function with the corrected values for transfer.
1450 	 */
1451 	ASSERT(pminsize);
1452 	if (size <= itask->it_ict->ict_op.op_max_burst_length) {
1453 		bsize = size;
1454 	} else if (*pminsize <= itask->it_ict->ict_op.op_max_burst_length) {
1455 		bsize = itask->it_ict->ict_op.op_max_burst_length;
1456 	} else {
1457 		*pminsize = itask->it_ict->ict_op.op_max_burst_length;
1458 		return (NULL);
1459 	}
1460 
1461 	/* Alloc buffer */
1462 	idm_buffer = idm_buf_alloc(itask->it_ict->ict_ic, NULL, bsize);
1463 	if (idm_buffer != NULL) {
1464 		result = stmf_alloc(STMF_STRUCT_DATA_BUF,
1465 		    sizeof (iscsit_buf_t), 0);
1466 		if (result != NULL) {
1467 			/* Fill in stmf_data_buf_t */
1468 			ibuf = result->db_port_private;
1469 			ibuf->ibuf_idm_buf = idm_buffer;
1470 			ibuf->ibuf_stmf_buf = result;
1471 			ibuf->ibuf_is_immed = B_FALSE;
1472 			result->db_flags = DB_DONT_CACHE;
1473 			result->db_buf_size = bsize;
1474 			result->db_data_size = bsize;
1475 			result->db_sglist_length = 1;
1476 			result->db_sglist[0].seg_addr = idm_buffer->idb_buf;
1477 			result->db_sglist[0].seg_length =
1478 			    idm_buffer->idb_buflen;
1479 			return (result);
1480 		}
1481 
1482 		/* Couldn't get the stmf_data_buf_t so free the buffer */
1483 		idm_buf_free(idm_buffer);
1484 	}
1485 
1486 	return (NULL);
1487 }
1488 
1489 /*ARGSUSED*/
1490 static void
1491 iscsit_dbuf_free(stmf_dbuf_store_t *ds, stmf_data_buf_t *dbuf)
1492 {
1493 	iscsit_buf_t *ibuf = dbuf->db_port_private;
1494 
1495 	if (ibuf->ibuf_is_immed) {
1496 		/*
1497 		 * The iscsit_buf_t structure itself will be freed with its
1498 		 * associated task.  Here we just need to free the PDU that
1499 		 * held the immediate data.
1500 		 */
1501 		idm_pdu_complete(ibuf->ibuf_immed_data_pdu, IDM_STATUS_SUCCESS);
1502 		ibuf->ibuf_immed_data_pdu = 0;
1503 	} else {
1504 		idm_buf_free(ibuf->ibuf_idm_buf);
1505 		stmf_free(dbuf);
1506 	}
1507 }
1508 
1509 /*ARGSUSED*/
1510 stmf_status_t
1511 iscsit_xfer_scsi_data(scsi_task_t *task, stmf_data_buf_t *dbuf,
1512     uint32_t ioflags)
1513 {
1514 	iscsit_task_t *iscsit_task = task->task_port_private;
1515 	iscsit_sess_t *ict_sess = iscsit_task->it_ict->ict_sess;
1516 	iscsit_buf_t *ibuf = dbuf->db_port_private;
1517 	int idm_rc;
1518 
1519 	/*
1520 	 * If we are aborting then we can ignore this request
1521 	 */
1522 	if (iscsit_task->it_stmf_abort) {
1523 		return (STMF_SUCCESS);
1524 	}
1525 
1526 	/*
1527 	 * If it's not immediate data then start the transfer
1528 	 */
1529 	ASSERT(ibuf->ibuf_is_immed == B_FALSE);
1530 	if (dbuf->db_flags & DB_DIRECTION_TO_RPORT) {
1531 		/*
1532 		 * The DB_SEND_STATUS_GOOD flag in the STMF data buffer allows
1533 		 * the port provider to phase-collapse, i.e. send the status
1534 		 * along with the final data PDU for the command. The port
1535 		 * provider passes this request to the transport layer by
1536 		 * setting a flag IDM_TASK_PHASECOLLAPSE_REQ in the task.
1537 		 */
1538 		if (dbuf->db_flags & DB_SEND_STATUS_GOOD)
1539 			iscsit_task->it_idm_task->idt_flags |=
1540 			    IDM_TASK_PHASECOLLAPSE_REQ;
1541 		/*
1542 		 * IDM will call iscsit_build_hdr so lock now to serialize
1543 		 * access to the SN values.  We need to lock here to enforce
1544 		 * lock ordering
1545 		 */
1546 		mutex_enter(&ict_sess->ist_sn_mutex);
1547 		idm_rc = idm_buf_tx_to_ini(iscsit_task->it_idm_task,
1548 		    ibuf->ibuf_idm_buf, dbuf->db_relative_offset,
1549 		    dbuf->db_data_size, &iscsit_buf_xfer_cb, dbuf);
1550 		mutex_exit(&ict_sess->ist_sn_mutex);
1551 
1552 		return (iscsit_idm_to_stmf(idm_rc));
1553 	} else if (dbuf->db_flags & DB_DIRECTION_FROM_RPORT) {
1554 		/* Grab the SN lock (see comment above) */
1555 		mutex_enter(&ict_sess->ist_sn_mutex);
1556 		idm_rc = idm_buf_rx_from_ini(iscsit_task->it_idm_task,
1557 		    ibuf->ibuf_idm_buf, dbuf->db_relative_offset,
1558 		    dbuf->db_data_size, &iscsit_buf_xfer_cb, dbuf);
1559 		mutex_exit(&ict_sess->ist_sn_mutex);
1560 
1561 		return (iscsit_idm_to_stmf(idm_rc));
1562 	}
1563 
1564 	/* What are we supposed to do if there is no direction? */
1565 	return (STMF_INVALID_ARG);
1566 }
1567 
1568 static void
1569 iscsit_buf_xfer_cb(idm_buf_t *idb, idm_status_t status)
1570 {
1571 	iscsit_task_t *itask = idb->idb_task_binding->idt_private;
1572 	stmf_data_buf_t *dbuf = idb->idb_cb_arg;
1573 
1574 	dbuf->db_xfer_status = iscsit_idm_to_stmf(status);
1575 
1576 	/*
1577 	 * If the task has been aborted then we don't need to call STMF
1578 	 */
1579 	if (itask->it_stmf_abort) {
1580 		return;
1581 	}
1582 
1583 	/*
1584 	 * For ISCSI over TCP (not iSER), the last SCSI Data PDU passed
1585 	 * for a successful command contains the status as requested by
1586 	 * by COMSTAR (via the DB_SEND_STATUS_GOOD flag). But the iSER
1587 	 * transport does not support phase-collapse. So pretend we are
1588 	 * COMSTAR and send the status in a separate PDU now.
1589 	 */
1590 	if (idb->idb_task_binding->idt_flags & IDM_TASK_PHASECOLLAPSE_SUCCESS) {
1591 		/*
1592 		 * Mark task complete and notify COMSTAR
1593 		 * that the status has been sent.
1594 		 */
1595 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1596 		stmf_send_status_done(itask->it_stmf_task,
1597 		    iscsit_idm_to_stmf(status), STMF_IOF_LPORT_DONE);
1598 	} else if ((dbuf->db_flags & DB_SEND_STATUS_GOOD) &&
1599 	    status == IDM_STATUS_SUCCESS) {
1600 
1601 		/*
1602 		 * The iscsi target port provider - for iSER, emulates the
1603 		 * DB_SEND_STATUS_GOOD optimization if requested by STMF;
1604 		 * it sends the status in a separate PDU after the data
1605 		 * transfer. In this case the port provider should first
1606 		 * call stmf_data_xfer_done() to mark the transfer complete
1607 		 * and then send the status. Although STMF will free the
1608 		 * buffer at the time the task is freed, even if the transfer
1609 		 * is not marked complete, this behavior makes statistics
1610 		 * gathering and task state tracking more difficult than it
1611 		 * needs to be.
1612 		 */
1613 		stmf_data_xfer_done(itask->it_stmf_task, dbuf, 0);
1614 		if (iscsit_send_scsi_status(itask->it_stmf_task, 0)
1615 		    != STMF_SUCCESS) {
1616 			stmf_send_status_done(itask->it_stmf_task,
1617 			    STMF_FAILURE, STMF_IOF_LPORT_DONE);
1618 		}
1619 	} else {
1620 		stmf_data_xfer_done(itask->it_stmf_task, dbuf, 0);
1621 		/* don't touch dbuf after stmf_data_xfer_done */
1622 	}
1623 }
1624 
1625 
1626 /*ARGSUSED*/
1627 stmf_status_t
1628 iscsit_send_scsi_status(scsi_task_t *task, uint32_t ioflags)
1629 {
1630 	iscsit_task_t *itask = task->task_port_private;
1631 	iscsi_scsi_rsp_hdr_t *rsp;
1632 	idm_pdu_t *pdu;
1633 	int resp_datalen;
1634 
1635 	/*
1636 	 * If this task is aborted then we don't need to respond.
1637 	 */
1638 	if (itask->it_stmf_abort) {
1639 		return (STMF_SUCCESS);
1640 	}
1641 
1642 	/*
1643 	 * If this is a task management status, handle it elsewhere.
1644 	 */
1645 	if (task->task_mgmt_function != TM_NONE) {
1646 		/*
1647 		 * Don't wait for the PDU completion to tell STMF
1648 		 * the task is done -- it doesn't really matter and
1649 		 * it makes life complicated if STMF later asks us to
1650 		 * abort the request and we don't know whether the
1651 		 * status has been sent or not.
1652 		 */
1653 		itask->it_tm_responded = B_TRUE;
1654 		iscsit_send_task_mgmt_resp(itask->it_tm_pdu,
1655 		    (task->task_completion_status == STMF_SUCCESS) ?
1656 		    SCSI_TCP_TM_RESP_COMPLETE : SCSI_TCP_TM_RESP_FUNC_NOT_SUPP);
1657 		stmf_send_status_done(task, STMF_SUCCESS,
1658 		    STMF_IOF_LPORT_DONE);
1659 		return (STMF_SUCCESS);
1660 	}
1661 
1662 	/*
1663 	 * Remove the task from the session task list
1664 	 */
1665 	iscsit_task_done(itask);
1666 
1667 	/*
1668 	 * Send status
1669 	 */
1670 	mutex_enter(&itask->it_idm_task->idt_mutex);
1671 	if ((itask->it_idm_task->idt_state == TASK_ACTIVE) &&
1672 	    (task->task_completion_status == STMF_SUCCESS) &&
1673 	    (task->task_sense_length == 0) &&
1674 	    (task->task_resid == 0)) {
1675 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1676 		/* PDU callback releases task hold */
1677 		idm_task_hold(itask->it_idm_task);
1678 		mutex_exit(&itask->it_idm_task->idt_mutex);
1679 		/*
1680 		 * Fast path.  Cached status PDU's are already
1681 		 * initialized.  We just need to fill in
1682 		 * connection and task information. StatSN is
1683 		 * incremented by 1 for every status sent a
1684 		 * connection.
1685 		 */
1686 		pdu = kmem_cache_alloc(iscsit_status_pdu_cache, KM_SLEEP);
1687 		pdu->isp_ic = itask->it_ict->ict_ic;
1688 		pdu->isp_private = itask;
1689 		pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
1690 
1691 		rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1692 		rsp->itt = itask->it_itt;
1693 		/*
1694 		 * ExpDataSN is the number of R2T and Data-In (read)
1695 		 * PDUs the target has sent for the SCSI command.
1696 		 *
1697 		 * Since there is no support for bidirectional transfer
1698 		 * yet, either idt_exp_datasn or idt_exp_rttsn, but not
1699 		 * both is valid at any time
1700 		 */
1701 		rsp->expdatasn = (itask->it_idm_task->idt_exp_datasn != 0) ?
1702 		    htonl(itask->it_idm_task->idt_exp_datasn):
1703 		    htonl(itask->it_idm_task->idt_exp_rttsn);
1704 		rsp->cmd_status = task->task_scsi_status;
1705 		iscsit_pdu_tx(pdu);
1706 		return (STMF_SUCCESS);
1707 	} else {
1708 		if (itask->it_idm_task->idt_state != TASK_ACTIVE) {
1709 			mutex_exit(&itask->it_idm_task->idt_mutex);
1710 			return (STMF_FAILURE);
1711 		}
1712 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1713 		/* PDU callback releases task hold */
1714 		idm_task_hold(itask->it_idm_task);
1715 		mutex_exit(&itask->it_idm_task->idt_mutex);
1716 
1717 		resp_datalen = (task->task_sense_length == 0) ? 0 :
1718 		    (task->task_sense_length + sizeof (uint16_t));
1719 
1720 		pdu = idm_pdu_alloc(sizeof (iscsi_hdr_t), resp_datalen);
1721 		idm_pdu_init(pdu, itask->it_ict->ict_ic, itask,
1722 		    iscsit_send_status_done);
1723 		pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
1724 
1725 		rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1726 		bzero(rsp, sizeof (*rsp));
1727 		rsp->opcode = ISCSI_OP_SCSI_RSP;
1728 
1729 		rsp->flags = ISCSI_FLAG_FINAL;
1730 		if (task->task_status_ctrl & TASK_SCTRL_OVER) {
1731 			rsp->flags |= ISCSI_FLAG_CMD_OVERFLOW;
1732 		} else if (task->task_status_ctrl & TASK_SCTRL_UNDER) {
1733 			rsp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
1734 		}
1735 
1736 		rsp->bi_residual_count = 0;
1737 		rsp->residual_count = htonl(task->task_resid);
1738 		rsp->itt = itask->it_itt;
1739 		rsp->response = ISCSI_STATUS_CMD_COMPLETED;
1740 		rsp->expdatasn = (itask->it_idm_task->idt_exp_datasn != 0) ?
1741 		    htonl(itask->it_idm_task->idt_exp_datasn):
1742 		    htonl(itask->it_idm_task->idt_exp_rttsn);
1743 		rsp->cmd_status = task->task_scsi_status;
1744 		if (task->task_sense_length != 0) {
1745 			/*
1746 			 * Add a byte to provide the sense length in
1747 			 * the response
1748 			 */
1749 			*(uint16_t *)((void *)pdu->isp_data) =
1750 			    htons(task->task_sense_length);
1751 			bcopy(task->task_sense_data,
1752 			    (uint8_t *)pdu->isp_data +
1753 			    sizeof (uint16_t),
1754 			    task->task_sense_length);
1755 			hton24(rsp->dlength, resp_datalen);
1756 		}
1757 
1758 		DTRACE_PROBE5(iscsi__scsi__response,
1759 		    iscsit_conn_t *, itask->it_ict,
1760 		    uint8_t, rsp->response,
1761 		    uint8_t, rsp->cmd_status,
1762 		    idm_pdu_t *, pdu,
1763 		    scsi_task_t *, task);
1764 
1765 		iscsit_pdu_tx(pdu);
1766 
1767 		return (STMF_SUCCESS);
1768 	}
1769 }
1770 
1771 /*ARGSUSED*/
1772 static void
1773 iscsit_send_good_status_done(idm_pdu_t *pdu, idm_status_t status)
1774 {
1775 	iscsit_task_t	*itask;
1776 	boolean_t	aborted;
1777 
1778 	itask = pdu->isp_private;
1779 	aborted = itask->it_stmf_abort;
1780 
1781 	/*
1782 	 * After releasing the hold the task may be freed at any time so
1783 	 * don't touch it.
1784 	 */
1785 	idm_task_rele(itask->it_idm_task);
1786 	if (!aborted) {
1787 		stmf_send_status_done(itask->it_stmf_task,
1788 		    iscsit_idm_to_stmf(pdu->isp_status), STMF_IOF_LPORT_DONE);
1789 	}
1790 	kmem_cache_free(iscsit_status_pdu_cache, pdu);
1791 }
1792 
1793 /*ARGSUSED*/
1794 static void
1795 iscsit_send_status_done(idm_pdu_t *pdu, idm_status_t status)
1796 {
1797 	iscsit_task_t	 *itask;
1798 	boolean_t	aborted;
1799 
1800 	itask = pdu->isp_private;
1801 	aborted = itask->it_stmf_abort;
1802 
1803 	/*
1804 	 * After releasing the hold the task may be freed at any time so
1805 	 * don't touch it.
1806 	 */
1807 	idm_task_rele(itask->it_idm_task);
1808 	if (!aborted) {
1809 		stmf_send_status_done(itask->it_stmf_task,
1810 		    iscsit_idm_to_stmf(pdu->isp_status), STMF_IOF_LPORT_DONE);
1811 	}
1812 	idm_pdu_free(pdu);
1813 }
1814 
1815 
1816 void
1817 iscsit_lport_task_free(scsi_task_t *task)
1818 {
1819 	iscsit_task_t *itask = task->task_port_private;
1820 
1821 	/* We only call idm_task_start for regular tasks, not task management */
1822 	if (task->task_mgmt_function == TM_NONE) {
1823 		idm_task_done(itask->it_idm_task);
1824 		iscsit_task_free(itask);
1825 		return;
1826 	} else {
1827 		iscsit_tm_task_free(itask);
1828 	}
1829 }
1830 
1831 /*ARGSUSED*/
1832 stmf_status_t
1833 iscsit_abort(stmf_local_port_t *lport, int abort_cmd, void *arg, uint32_t flags)
1834 {
1835 	scsi_task_t	*st = (scsi_task_t *)arg;
1836 	iscsit_task_t	*iscsit_task;
1837 	idm_task_t	*idt;
1838 
1839 	/*
1840 	 * If this is a task management request then there's really not much to
1841 	 * do.
1842 	 */
1843 	if (st->task_mgmt_function != TM_NONE) {
1844 		return (STMF_ABORT_SUCCESS);
1845 	}
1846 
1847 	/*
1848 	 * Regular task, start cleaning up
1849 	 */
1850 	iscsit_task = st->task_port_private;
1851 	idt = iscsit_task->it_idm_task;
1852 	mutex_enter(&iscsit_task->it_mutex);
1853 	iscsit_task->it_stmf_abort = B_TRUE;
1854 	if (iscsit_task->it_aborted) {
1855 		mutex_exit(&iscsit_task->it_mutex);
1856 		/*
1857 		 * Task is no longer active
1858 		 */
1859 		iscsit_task_done(iscsit_task);
1860 
1861 		/*
1862 		 * STMF specification is wrong... says to return
1863 		 * STMF_ABORTED, the code actually looks for
1864 		 * STMF_ABORT_SUCCESS.
1865 		 */
1866 		return (STMF_ABORT_SUCCESS);
1867 	} else {
1868 		mutex_exit(&iscsit_task->it_mutex);
1869 		/*
1870 		 * Call IDM to abort the task.  Due to a variety of
1871 		 * circumstances the task may already be in the process of
1872 		 * aborting.
1873 		 * We'll let IDM worry about rationalizing all that except
1874 		 * for one particular instance.  If the state of the task
1875 		 * is TASK_COMPLETE, we need to indicate to the framework
1876 		 * that we are in fact done.  This typically happens with
1877 		 * framework-initiated task management type requests
1878 		 * (e.g. abort task).
1879 		 */
1880 		if (idt->idt_state == TASK_COMPLETE) {
1881 			idm_refcnt_wait_ref(&idt->idt_refcnt);
1882 			return (STMF_ABORT_SUCCESS);
1883 		} else {
1884 			idm_task_abort(idt->idt_ic, idt, AT_TASK_MGMT_ABORT);
1885 			return (STMF_SUCCESS);
1886 		}
1887 	}
1888 
1889 	/*NOTREACHED*/
1890 }
1891 
1892 /*ARGSUSED*/
1893 void
1894 iscsit_ctl(stmf_local_port_t *lport, int cmd, void *arg)
1895 {
1896 	iscsit_tgt_t		*iscsit_tgt;
1897 
1898 	ASSERT((cmd == STMF_CMD_LPORT_ONLINE) ||
1899 	    (cmd == STMF_ACK_LPORT_ONLINE_COMPLETE) ||
1900 	    (cmd == STMF_CMD_LPORT_OFFLINE) ||
1901 	    (cmd == STMF_ACK_LPORT_OFFLINE_COMPLETE));
1902 
1903 	iscsit_tgt = (iscsit_tgt_t *)lport->lport_port_private;
1904 
1905 	switch (cmd) {
1906 	case STMF_CMD_LPORT_ONLINE:
1907 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_ONLINE_REQ);
1908 		break;
1909 	case STMF_CMD_LPORT_OFFLINE:
1910 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_OFFLINE_REQ);
1911 		break;
1912 	case STMF_ACK_LPORT_ONLINE_COMPLETE:
1913 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_ONLINE_COMPLETE_ACK);
1914 		break;
1915 	case STMF_ACK_LPORT_OFFLINE_COMPLETE:
1916 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_OFFLINE_COMPLETE_ACK);
1917 		break;
1918 
1919 	default:
1920 		break;
1921 	}
1922 }
1923 
1924 static stmf_status_t
1925 iscsit_idm_to_stmf(idm_status_t idmrc)
1926 {
1927 	switch (idmrc) {
1928 	case IDM_STATUS_SUCCESS:
1929 		return (STMF_SUCCESS);
1930 	default:
1931 		return (STMF_FAILURE);
1932 	}
1933 	/*NOTREACHED*/
1934 }
1935 
1936 void
1937 iscsit_op_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu)
1938 {
1939 	iscsit_conn_t		*ict = ic->ic_handle;
1940 
1941 	if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
1942 		iscsit_post_scsi_cmd(ic, rx_pdu);
1943 	}
1944 	iscsit_process_pdu_in_queue(ict->ict_sess);
1945 }
1946 
1947 /*
1948  * ISCSI protocol
1949  */
1950 
1951 void
1952 iscsit_post_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu)
1953 {
1954 	iscsit_conn_t		*ict;
1955 	iscsit_task_t		*itask;
1956 	scsi_task_t		*task;
1957 	iscsit_buf_t		*ibuf;
1958 	iscsi_scsi_cmd_hdr_t	*iscsi_scsi =
1959 	    (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
1960 	iscsi_addl_hdr_t	*ahs_hdr;
1961 	uint16_t		addl_cdb_len = 0;
1962 
1963 	ict = ic->ic_handle;
1964 
1965 	itask = iscsit_task_alloc(ict);
1966 	if (itask == NULL) {
1967 		/* Finish processing request */
1968 		iscsit_set_cmdsn(ict, rx_pdu);
1969 
1970 		iscsit_send_direct_scsi_resp(ict, rx_pdu,
1971 		    ISCSI_STATUS_CMD_COMPLETED, STATUS_BUSY);
1972 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
1973 		return;
1974 	}
1975 
1976 	/*
1977 	 * Note CmdSN and ITT in task.  IDM will have already validated this
1978 	 * request against the connection state so we don't need to check
1979 	 * that (the connection may have changed state in the meantime but
1980 	 * we will catch that when we try to send a response)
1981 	 */
1982 	itask->it_cmdsn = ntohl(iscsi_scsi->cmdsn);
1983 	itask->it_itt = iscsi_scsi->itt;
1984 
1985 	/*
1986 	 * Check for extended CDB AHS
1987 	 */
1988 	if (iscsi_scsi->hlength > 0) {
1989 		ahs_hdr = (iscsi_addl_hdr_t *)iscsi_scsi;
1990 		addl_cdb_len = ((ahs_hdr->ahs_hlen_hi << 8) |
1991 		    ahs_hdr->ahs_hlen_lo) - 1; /* Adjust for reserved byte */
1992 		if (((addl_cdb_len + 4) / sizeof (uint32_t)) >
1993 		    iscsi_scsi->hlength) {
1994 			/* Mangled header info, drop it */
1995 			idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
1996 			return;
1997 		}
1998 	}
1999 
2000 	ict = rx_pdu->isp_ic->ic_handle; /* IDM client private */
2001 
2002 	/*
2003 	 * Add task to session list.  This function will also check to
2004 	 * ensure that the task does not already exist.
2005 	 */
2006 	if (iscsit_task_start(itask) != IDM_STATUS_SUCCESS) {
2007 		/*
2008 		 * Task exists, free all resources and reject.  Don't
2009 		 * update expcmdsn in this case because RFC 3720 says
2010 		 * "The CmdSN of the rejected command PDU (if it is a
2011 		 * non-immediate command) MUST NOT be considered received
2012 		 * by the target (i.e., a command sequence gap must be
2013 		 * assumed for the CmdSN), even though the CmdSN of the
2014 		 * rejected command PDU may be reliably ascertained.  Upon
2015 		 * receiving the Reject, the initiator MUST plug the CmdSN
2016 		 * gap in order to continue to use the session.  The gap
2017 		 * may be plugged either by transmitting a command PDU
2018 		 * with the same CmdSN, or by aborting the task (see section
2019 		 * 6.9 on how an abort may plug a CmdSN gap)." (Section 6.3)
2020 		 */
2021 		iscsit_task_free(itask);
2022 		iscsit_send_reject(ict, rx_pdu, ISCSI_REJECT_TASK_IN_PROGRESS);
2023 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2024 		return;
2025 	}
2026 
2027 	/* Update sequence numbers */
2028 	iscsit_set_cmdsn(ict, rx_pdu);
2029 
2030 	/*
2031 	 * Allocate STMF task
2032 	 */
2033 	itask->it_stmf_task = stmf_task_alloc(
2034 	    itask->it_ict->ict_sess->ist_lport,
2035 	    itask->it_ict->ict_sess->ist_stmf_sess, iscsi_scsi->lun,
2036 	    16 + addl_cdb_len, 0);
2037 	if (itask->it_stmf_task == NULL) {
2038 		/*
2039 		 * Either stmf really couldn't get memory for a task or,
2040 		 * more likely, the LU is currently in reset.  Either way
2041 		 * we have no choice but to fail the request.
2042 		 */
2043 		iscsit_task_done(itask);
2044 		iscsit_task_free(itask);
2045 		iscsit_send_direct_scsi_resp(ict, rx_pdu,
2046 		    ISCSI_STATUS_CMD_COMPLETED, STATUS_BUSY);
2047 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2048 		return;
2049 	}
2050 
2051 	task = itask->it_stmf_task;
2052 	task->task_port_private = itask;
2053 
2054 	bcopy(iscsi_scsi->lun, task->task_lun_no, sizeof (task->task_lun_no));
2055 
2056 	/*
2057 	 * iSCSI and Comstar use the same values.  Should we rely on this
2058 	 * or translate them bit-wise?
2059 	 */
2060 
2061 	task->task_flags =
2062 	    (((iscsi_scsi->flags & ISCSI_FLAG_CMD_READ) ? TF_READ_DATA : 0) |
2063 	    ((iscsi_scsi->flags & ISCSI_FLAG_CMD_WRITE) ? TF_WRITE_DATA : 0) |
2064 	    ((rx_pdu->isp_datalen == 0) ? 0 : TF_INITIAL_BURST));
2065 
2066 	switch (iscsi_scsi->flags & ISCSI_FLAG_CMD_ATTR_MASK) {
2067 	case ISCSI_ATTR_UNTAGGED:
2068 		break;
2069 	case ISCSI_ATTR_SIMPLE:
2070 		task->task_additional_flags |= TF_ATTR_SIMPLE_QUEUE;
2071 		break;
2072 	case ISCSI_ATTR_ORDERED:
2073 		task->task_additional_flags |= TF_ATTR_ORDERED_QUEUE;
2074 		break;
2075 	case ISCSI_ATTR_HEAD_OF_QUEUE:
2076 		task->task_additional_flags |= TF_ATTR_HEAD_OF_QUEUE;
2077 		break;
2078 	case ISCSI_ATTR_ACA:
2079 		task->task_additional_flags |= TF_ATTR_ACA;
2080 		break;
2081 	default:
2082 		/* Protocol error but just take it, treat as untagged */
2083 		break;
2084 	}
2085 
2086 
2087 	task->task_additional_flags = 0;
2088 	task->task_priority = 0;
2089 	task->task_mgmt_function = TM_NONE;
2090 
2091 	/*
2092 	 * This "task_max_nbufs" doesn't map well to BIDI.  We probably need
2093 	 * parameter for each direction.  "MaxOutstandingR2T" may very well
2094 	 * be set to one which could prevent us from doing simultaneous
2095 	 * transfers in each direction.
2096 	 */
2097 	task->task_max_nbufs = (iscsi_scsi->flags & ISCSI_FLAG_CMD_WRITE) ?
2098 	    ict->ict_op.op_max_outstanding_r2t : STMF_BUFS_MAX;
2099 	task->task_cmd_seq_no = ntohl(iscsi_scsi->itt);
2100 	task->task_expected_xfer_length = ntohl(iscsi_scsi->data_length);
2101 
2102 	/* Copy CDB */
2103 	bcopy(iscsi_scsi->scb, task->task_cdb, 16);
2104 	if (addl_cdb_len > 0) {
2105 		bcopy(ahs_hdr->ahs_extscb, task->task_cdb + 16, addl_cdb_len);
2106 	}
2107 
2108 	DTRACE_ISCSI_3(scsi__command, idm_conn_t *, ic,
2109 	    iscsi_scsi_cmd_hdr_t *, (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr,
2110 	    scsi_task_t *, task);
2111 
2112 	/*
2113 	 * Copy the transport header into the task handle from the PDU
2114 	 * handle. The transport header describes this task's remote tagged
2115 	 * buffer.
2116 	 */
2117 	if (rx_pdu->isp_transport_hdrlen != 0) {
2118 		bcopy(rx_pdu->isp_transport_hdr,
2119 		    itask->it_idm_task->idt_transport_hdr,
2120 		    rx_pdu->isp_transport_hdrlen);
2121 	}
2122 
2123 	/*
2124 	 * Tell IDM about our new active task
2125 	 */
2126 	idm_task_start(itask->it_idm_task, (uintptr_t)itask->it_itt);
2127 
2128 	/*
2129 	 * If we have any immediate data then setup the immediate buffer
2130 	 * context that comes with the task
2131 	 */
2132 	if (rx_pdu->isp_datalen) {
2133 		ibuf = itask->it_immed_data;
2134 		ibuf->ibuf_immed_data_pdu = rx_pdu;
2135 		ibuf->ibuf_stmf_buf->db_data_size = rx_pdu->isp_datalen;
2136 		ibuf->ibuf_stmf_buf->db_buf_size = rx_pdu->isp_datalen;
2137 		ibuf->ibuf_stmf_buf->db_relative_offset = 0;
2138 		ibuf->ibuf_stmf_buf->db_sglist[0].seg_length =
2139 		    rx_pdu->isp_datalen;
2140 		ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr = rx_pdu->isp_data;
2141 
2142 		DTRACE_ISCSI_8(xfer__start, idm_conn_t *, ic,
2143 		    uintptr_t, ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr,
2144 		    uint32_t, ibuf->ibuf_stmf_buf->db_relative_offset,
2145 		    uint64_t, 0, uint32_t, 0, uint32_t, 0, /* no raddr */
2146 		    uint32_t, rx_pdu->isp_datalen, int, XFER_BUF_TX_TO_INI);
2147 
2148 		/*
2149 		 * For immediate data transfer, there is no callback from
2150 		 * stmf to indicate that the initial burst of data is
2151 		 * transferred successfully. In some cases, the task can
2152 		 * get freed before execution returns from stmf_post_task.
2153 		 * Although this xfer-start/done probe accurately tracks
2154 		 * the size of the transfer, it does only provide a best
2155 		 * effort on the timing of the transfer.
2156 		 */
2157 		DTRACE_ISCSI_8(xfer__done, idm_conn_t *, ic,
2158 		    uintptr_t, ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr,
2159 		    uint32_t, ibuf->ibuf_stmf_buf->db_relative_offset,
2160 		    uint64_t, 0, uint32_t, 0, uint32_t, 0, /* no raddr */
2161 		    uint32_t, rx_pdu->isp_datalen, int, XFER_BUF_TX_TO_INI);
2162 		stmf_post_task(task, ibuf->ibuf_stmf_buf);
2163 	} else {
2164 
2165 		stmf_post_task(task, NULL);
2166 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2167 	}
2168 }
2169 
2170 void
2171 iscsit_deferred_dispatch(idm_pdu_t *rx_pdu)
2172 {
2173 	iscsit_conn_t *ict = rx_pdu->isp_ic->ic_handle;
2174 
2175 	/*
2176 	 * If this isn't a login packet, we need a session.  Otherwise
2177 	 * this is a protocol error (perhaps one IDM should've caught?).
2178 	 */
2179 	if (IDM_PDU_OPCODE(rx_pdu) != ISCSI_OP_LOGIN_CMD &&
2180 	    ict->ict_sess == NULL) {
2181 		DTRACE_PROBE2(iscsi__idm__deferred__no__session,
2182 		    iscsit_conn_t *, ict, idm_pdu_t *, rx_pdu);
2183 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2184 		return;
2185 	}
2186 
2187 	/*
2188 	 * If the connection has been lost then ignore new PDU's
2189 	 */
2190 	mutex_enter(&ict->ict_mutex);
2191 	if (ict->ict_lost) {
2192 		mutex_exit(&ict->ict_mutex);
2193 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2194 		return;
2195 	}
2196 
2197 	/*
2198 	 * Grab a hold on the connection to prevent it from going away
2199 	 * between now and when the taskq function is called.
2200 	 */
2201 	iscsit_conn_dispatch_hold(ict);
2202 	mutex_exit(&ict->ict_mutex);
2203 
2204 	taskq_dispatch_ent(iscsit_global.global_dispatch_taskq,
2205 	    iscsit_deferred, rx_pdu, 0, &rx_pdu->isp_tqent);
2206 }
2207 
2208 static void
2209 iscsit_deferred(void *rx_pdu_void)
2210 {
2211 	idm_pdu_t		*rx_pdu = rx_pdu_void;
2212 	idm_conn_t		*ic = rx_pdu->isp_ic;
2213 	iscsit_conn_t		*ict = ic->ic_handle;
2214 
2215 	/*
2216 	 * NOP and Task Management Commands can be marked for immediate
2217 	 * delivery. Commands marked as 'Immediate' are to be considered
2218 	 * for execution as soon as they arrive on the target. So these
2219 	 * should not be checked for sequence order and put in a queue.
2220 	 * The CmdSN is not advanced for Immediate Commands.
2221 	 */
2222 	switch (IDM_PDU_OPCODE(rx_pdu)) {
2223 	case ISCSI_OP_NOOP_OUT:
2224 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2225 			iscsit_set_cmdsn(ict, rx_pdu);
2226 			iscsit_pdu_op_noop(ict, rx_pdu);
2227 		}
2228 		break;
2229 	case ISCSI_OP_LOGIN_CMD:
2230 		iscsit_pdu_op_login_cmd(ict, rx_pdu);
2231 		iscsit_conn_dispatch_rele(ict);
2232 		return;
2233 	case ISCSI_OP_TEXT_CMD:
2234 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2235 			iscsit_set_cmdsn(ict, rx_pdu);
2236 			iscsit_pdu_op_text_cmd(ict, rx_pdu);
2237 		}
2238 		break;
2239 	case ISCSI_OP_LOGOUT_CMD:
2240 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2241 			iscsit_set_cmdsn(ict, rx_pdu);
2242 			iscsit_pdu_op_logout_cmd(ict, rx_pdu);
2243 		}
2244 		break;
2245 	default:
2246 		/* Protocol error.  IDM should have caught this */
2247 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2248 		ASSERT(0);
2249 		break;
2250 	}
2251 	/*
2252 	 * Check if there are other PDUs in the session staging queue
2253 	 * waiting to be posted to SCSI layer.
2254 	 */
2255 	iscsit_process_pdu_in_queue(ict->ict_sess);
2256 
2257 	iscsit_conn_dispatch_rele(ict);
2258 }
2259 
2260 static void
2261 iscsit_send_direct_scsi_resp(iscsit_conn_t *ict, idm_pdu_t *rx_pdu,
2262     uint8_t response, uint8_t cmd_status)
2263 {
2264 	idm_pdu_t			*rsp_pdu;
2265 	idm_conn_t			*ic;
2266 	iscsi_scsi_rsp_hdr_t		*resp;
2267 	iscsi_scsi_cmd_hdr_t		*req =
2268 	    (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
2269 
2270 	ic = ict->ict_ic;
2271 
2272 	rsp_pdu = idm_pdu_alloc(sizeof (iscsi_scsi_rsp_hdr_t), 0);
2273 	idm_pdu_init(rsp_pdu, ic, NULL, NULL);
2274 	/*
2275 	 * StatSN is incremented by 1 for every response sent on
2276 	 * a connection except for responses sent as a result of
2277 	 * a retry or SNACK
2278 	 */
2279 	rsp_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2280 
2281 	resp = (iscsi_scsi_rsp_hdr_t *)rsp_pdu->isp_hdr;
2282 
2283 	resp->opcode = ISCSI_OP_SCSI_RSP;
2284 	resp->flags = ISCSI_FLAG_FINAL;
2285 	resp->response = response;
2286 	resp->cmd_status = cmd_status;
2287 	resp->itt = req->itt;
2288 	if ((response == ISCSI_STATUS_CMD_COMPLETED) &&
2289 	    (req->data_length != 0) &&
2290 	    ((req->flags & ISCSI_FLAG_CMD_READ) ||
2291 	    (req->flags & ISCSI_FLAG_CMD_WRITE))) {
2292 		resp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
2293 		resp->residual_count = req->data_length;
2294 	}
2295 
2296 	DTRACE_PROBE4(iscsi__scsi__direct__response,
2297 	    iscsit_conn_t *, ict,
2298 	    uint8_t, resp->response,
2299 	    uint8_t, resp->cmd_status,
2300 	    idm_pdu_t *, rsp_pdu);
2301 
2302 	iscsit_pdu_tx(rsp_pdu);
2303 }
2304 
2305 void
2306 iscsit_send_task_mgmt_resp(idm_pdu_t *tm_resp_pdu, uint8_t tm_status)
2307 {
2308 	iscsi_scsi_task_mgt_rsp_hdr_t	*tm_resp;
2309 
2310 	/*
2311 	 * The target must take note of the last-sent StatSN.
2312 	 * The StatSN is to be incremented after sending a
2313 	 * task management response. Digest recovery can only
2314 	 * work if StatSN is incremented.
2315 	 */
2316 	tm_resp_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2317 	tm_resp = (iscsi_scsi_task_mgt_rsp_hdr_t *)tm_resp_pdu->isp_hdr;
2318 	tm_resp->response = tm_status;
2319 
2320 	DTRACE_PROBE3(iscsi__scsi__tm__response,
2321 	    iscsit_conn_t *, tm_resp_pdu->isp_ic->ic_handle,
2322 	    uint8_t, tm_resp->response,
2323 	    idm_pdu_t *, tm_resp_pdu);
2324 	iscsit_pdu_tx(tm_resp_pdu);
2325 }
2326 
2327 void
2328 iscsit_op_scsi_task_mgmt(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2329 {
2330 	idm_pdu_t			*tm_resp_pdu;
2331 	iscsit_task_t			*itask;
2332 	iscsit_task_t			*tm_itask;
2333 	scsi_task_t			*task;
2334 	iscsi_scsi_task_mgt_hdr_t 	*iscsi_tm =
2335 	    (iscsi_scsi_task_mgt_hdr_t *)rx_pdu->isp_hdr;
2336 	iscsi_scsi_task_mgt_rsp_hdr_t 	*iscsi_tm_rsp =
2337 	    (iscsi_scsi_task_mgt_rsp_hdr_t *)rx_pdu->isp_hdr;
2338 	uint32_t			rtt, cmdsn, refcmdsn;
2339 	uint8_t				tm_func;
2340 
2341 	/*
2342 	 * Setup response PDU (response field will get filled in later)
2343 	 */
2344 	tm_resp_pdu = idm_pdu_alloc(sizeof (iscsi_scsi_task_mgt_rsp_hdr_t), 0);
2345 	if (tm_resp_pdu == NULL) {
2346 		/* Can't respond, just drop it */
2347 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2348 		return;
2349 	}
2350 	idm_pdu_init(tm_resp_pdu, ict->ict_ic, NULL, NULL);
2351 	iscsi_tm_rsp = (iscsi_scsi_task_mgt_rsp_hdr_t *)tm_resp_pdu->isp_hdr;
2352 	bzero(iscsi_tm_rsp, sizeof (iscsi_scsi_task_mgt_rsp_hdr_t));
2353 	iscsi_tm_rsp->opcode = ISCSI_OP_SCSI_TASK_MGT_RSP;
2354 	iscsi_tm_rsp->flags = ISCSI_FLAG_FINAL;
2355 	iscsi_tm_rsp->itt = rx_pdu->isp_hdr->itt;
2356 
2357 	/*
2358 	 * Figure out what we're being asked to do.
2359 	 */
2360 	DTRACE_PROBE4(iscsi__scsi__tm__request,
2361 	    iscsit_conn_t *, ict,
2362 	    uint8_t, (iscsi_tm->function & ISCSI_FLAG_TASK_MGMT_FUNCTION_MASK),
2363 	    uint32_t, iscsi_tm->rtt,
2364 	    idm_pdu_t *, rx_pdu);
2365 	switch (iscsi_tm->function & ISCSI_FLAG_TASK_MGMT_FUNCTION_MASK) {
2366 	case ISCSI_TM_FUNC_ABORT_TASK:
2367 		/*
2368 		 * STMF doesn't currently support the "abort task" task
2369 		 * management command although it does support aborting
2370 		 * an individual task.  We'll get STMF to abort the task
2371 		 * for us but handle the details of the task management
2372 		 * command ourselves.
2373 		 *
2374 		 * Find the task associated with the referenced task tag.
2375 		 */
2376 		rtt = iscsi_tm->rtt;
2377 		itask = (iscsit_task_t *)idm_task_find_by_handle(ict->ict_ic,
2378 		    (uintptr_t)rtt);
2379 
2380 		if (itask == NULL) {
2381 			cmdsn = ntohl(iscsi_tm->cmdsn);
2382 			refcmdsn = ntohl(iscsi_tm->refcmdsn);
2383 
2384 			/*
2385 			 * Task was not found. But the SCSI command could be
2386 			 * on the rxpdu wait queue. If RefCmdSN is within
2387 			 * the CmdSN window and less than CmdSN of the TM
2388 			 * function, return "Function Complete". Otherwise,
2389 			 * return "Task Does Not Exist".
2390 			 */
2391 
2392 			if (iscsit_cmdsn_in_window(ict, refcmdsn) &&
2393 			    iscsit_sna_lt(refcmdsn, cmdsn)) {
2394 				mutex_enter(&ict->ict_sess->ist_sn_mutex);
2395 				(void) iscsit_remove_pdu_from_queue(
2396 				    ict->ict_sess, refcmdsn);
2397 				iscsit_conn_dispatch_rele(ict);
2398 				mutex_exit(&ict->ict_sess->ist_sn_mutex);
2399 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2400 				    SCSI_TCP_TM_RESP_COMPLETE);
2401 			} else {
2402 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2403 				    SCSI_TCP_TM_RESP_NO_TASK);
2404 			}
2405 		} else {
2406 
2407 			/*
2408 			 * Tell STMF to abort the task.  This will do no harm
2409 			 * if the task is already complete.
2410 			 */
2411 			stmf_abort(STMF_QUEUE_TASK_ABORT, itask->it_stmf_task,
2412 			    STMF_ABORTED, NULL);
2413 
2414 			/*
2415 			 * Make sure the task hasn't already completed
2416 			 */
2417 			mutex_enter(&itask->it_idm_task->idt_mutex);
2418 			if ((itask->it_idm_task->idt_state == TASK_COMPLETE) ||
2419 			    (itask->it_idm_task->idt_state == TASK_IDLE)) {
2420 				/*
2421 				 * Task is complete, return "Task Does Not
2422 				 * Exist"
2423 				 */
2424 				mutex_exit(&itask->it_idm_task->idt_mutex);
2425 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2426 				    SCSI_TCP_TM_RESP_NO_TASK);
2427 			} else {
2428 				/*
2429 				 * STMF is now aborting the task, return
2430 				 * "Function Complete"
2431 				 */
2432 				mutex_exit(&itask->it_idm_task->idt_mutex);
2433 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2434 				    SCSI_TCP_TM_RESP_COMPLETE);
2435 			}
2436 			idm_task_rele(itask->it_idm_task);
2437 		}
2438 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2439 		return;
2440 
2441 	case ISCSI_TM_FUNC_ABORT_TASK_SET:
2442 		tm_func = TM_ABORT_TASK_SET;
2443 		break;
2444 
2445 	case ISCSI_TM_FUNC_CLEAR_ACA:
2446 		tm_func = TM_CLEAR_ACA;
2447 		break;
2448 
2449 	case ISCSI_TM_FUNC_CLEAR_TASK_SET:
2450 		tm_func = TM_CLEAR_TASK_SET;
2451 		break;
2452 
2453 	case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
2454 		tm_func = TM_LUN_RESET;
2455 		break;
2456 
2457 	case ISCSI_TM_FUNC_TARGET_WARM_RESET:
2458 		tm_func = TM_TARGET_WARM_RESET;
2459 		break;
2460 
2461 	case ISCSI_TM_FUNC_TARGET_COLD_RESET:
2462 		tm_func = TM_TARGET_COLD_RESET;
2463 		break;
2464 
2465 	case ISCSI_TM_FUNC_TASK_REASSIGN:
2466 		/*
2467 		 * We do not currently support allegiance reassignment.  When
2468 		 * we start supporting ERL1+, we will need to.
2469 		 */
2470 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2471 		    SCSI_TCP_TM_RESP_NO_ALLG_REASSN);
2472 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2473 		return;
2474 
2475 	default:
2476 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2477 		    SCSI_TCP_TM_RESP_REJECTED);
2478 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2479 		return;
2480 	}
2481 
2482 	tm_itask = iscsit_tm_task_alloc(ict);
2483 	if (tm_itask == NULL) {
2484 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2485 		    SCSI_TCP_TM_RESP_REJECTED);
2486 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2487 		return;
2488 	}
2489 
2490 
2491 	task = stmf_task_alloc(ict->ict_sess->ist_lport,
2492 	    ict->ict_sess->ist_stmf_sess, iscsi_tm->lun,
2493 	    0, STMF_TASK_EXT_NONE);
2494 	if (task == NULL) {
2495 		/*
2496 		 * If this happens, either the LU is in reset, couldn't
2497 		 * get memory, or some other condition in which we simply
2498 		 * can't complete this request.  It would be nice to return
2499 		 * an error code like "busy" but the closest we have is
2500 		 * "rejected".
2501 		 */
2502 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2503 		    SCSI_TCP_TM_RESP_REJECTED);
2504 		iscsit_tm_task_free(tm_itask);
2505 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2506 		return;
2507 	}
2508 
2509 	tm_itask->it_tm_pdu = tm_resp_pdu;
2510 	tm_itask->it_stmf_task = task;
2511 	task->task_port_private = tm_itask;
2512 	task->task_mgmt_function = tm_func;
2513 	task->task_additional_flags = TASK_AF_NO_EXPECTED_XFER_LENGTH;
2514 	task->task_priority = 0;
2515 	task->task_max_nbufs = STMF_BUFS_MAX;
2516 	task->task_cmd_seq_no = iscsi_tm->itt;
2517 	task->task_expected_xfer_length = 0;
2518 
2519 	stmf_post_task(task, NULL);
2520 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2521 }
2522 
2523 static void
2524 iscsit_pdu_op_noop(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2525 {
2526 	iscsi_nop_out_hdr_t *out = (iscsi_nop_out_hdr_t *)rx_pdu->isp_hdr;
2527 	iscsi_nop_in_hdr_t *in;
2528 	int resp_datalen;
2529 	idm_pdu_t *resp;
2530 
2531 	/* Ignore the response from initiator */
2532 	if ((out->itt == ISCSI_RSVD_TASK_TAG) ||
2533 	    (out->ttt != ISCSI_RSVD_TASK_TAG)) {
2534 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2535 		return;
2536 	}
2537 
2538 	/* Allocate a PDU to respond */
2539 	resp_datalen = ntoh24(out->dlength);
2540 	resp = idm_pdu_alloc(sizeof (iscsi_hdr_t), resp_datalen);
2541 	idm_pdu_init(resp, ict->ict_ic, NULL, NULL);
2542 	if (resp_datalen > 0) {
2543 		bcopy(rx_pdu->isp_data, resp->isp_data, resp_datalen);
2544 	}
2545 
2546 	/*
2547 	 * When sending a NOP-In as a response to a NOP-Out from the initiator,
2548 	 * the target must respond with the same initiator task tag that was
2549 	 * provided in the NOP-Out request, the target transfer tag must be
2550 	 * ISCSI_RSVD_TASK_TAG (0xffffffff) and StatSN will contain the next
2551 	 * status sequence number. The StatSN for the connection is advanced
2552 	 * after this PDU is sent.
2553 	 */
2554 	in = (iscsi_nop_in_hdr_t *)resp->isp_hdr;
2555 	bzero(in, sizeof (*in));
2556 	in->opcode = ISCSI_OP_NOOP_IN;
2557 	in->flags = ISCSI_FLAG_FINAL;
2558 	bcopy(out->lun, in->lun, 8);
2559 	in->itt		= out->itt;
2560 	in->ttt		= ISCSI_RSVD_TASK_TAG;
2561 	hton24(in->dlength, resp_datalen);
2562 	resp->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2563 	/* Any other field in resp to be set? */
2564 	iscsit_pdu_tx(resp);
2565 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2566 }
2567 
2568 static void
2569 iscsit_pdu_op_login_cmd(iscsit_conn_t	*ict, idm_pdu_t *rx_pdu)
2570 {
2571 
2572 	/*
2573 	 * Submit PDU to login state machine.  State machine will free the
2574 	 * PDU.
2575 	 */
2576 	iscsit_login_sm_event(ict, ILE_LOGIN_RCV, rx_pdu);
2577 }
2578 
2579 void
2580 iscsit_pdu_op_logout_cmd(iscsit_conn_t	*ict, idm_pdu_t *rx_pdu)
2581 {
2582 	iscsi_logout_hdr_t 	*logout_req =
2583 	    (iscsi_logout_hdr_t *)rx_pdu->isp_hdr;
2584 	iscsi_logout_rsp_hdr_t	*logout_rsp;
2585 	idm_pdu_t *resp;
2586 
2587 	/* Allocate a PDU to respond */
2588 	resp = idm_pdu_alloc(sizeof (iscsi_hdr_t), 0);
2589 	idm_pdu_init(resp, ict->ict_ic, NULL, NULL);
2590 	/*
2591 	 * The StatSN is to be sent to the initiator,
2592 	 * it is not required to increment the number
2593 	 * as the connection is terminating.
2594 	 */
2595 	resp->isp_flags |= IDM_PDU_SET_STATSN;
2596 	/*
2597 	 * Logout results in the immediate termination of all tasks except
2598 	 * if the logout reason is ISCSI_LOGOUT_REASON_RECOVERY.  The
2599 	 * connection state machine will drive this task cleanup automatically
2600 	 * so we don't need to handle that here.
2601 	 */
2602 	logout_rsp = (iscsi_logout_rsp_hdr_t *)resp->isp_hdr;
2603 	bzero(logout_rsp, sizeof (*logout_rsp));
2604 	logout_rsp->opcode = ISCSI_OP_LOGOUT_RSP;
2605 	logout_rsp->flags = ISCSI_FLAG_FINAL;
2606 	logout_rsp->itt = logout_req->itt;
2607 	if ((logout_req->flags & ISCSI_FLAG_LOGOUT_REASON_MASK) >
2608 	    ISCSI_LOGOUT_REASON_RECOVERY) {
2609 		logout_rsp->response = ISCSI_LOGOUT_RECOVERY_UNSUPPORTED;
2610 	} else {
2611 		logout_rsp->response = ISCSI_LOGOUT_SUCCESS;
2612 	}
2613 
2614 	iscsit_pdu_tx(resp);
2615 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2616 }
2617 
2618 /*
2619  * Calculate the number of outstanding commands we can process
2620  */
2621 int
2622 iscsit_cmd_window()
2623 {
2624 	/*
2625 	 * Instead of using a pre-defined constant for the command window,
2626 	 * it should be made confiurable and dynamic. With MC/S, sequence
2627 	 * numbers will be used up at a much faster rate than with SC/S.
2628 	 */
2629 	return	(ISCSIT_MAX_WINDOW);
2630 }
2631 
2632 /*
2633  * Set local registers based on incoming PDU
2634  */
2635 void
2636 iscsit_set_cmdsn(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2637 {
2638 	iscsit_sess_t *ist;
2639 	iscsi_scsi_cmd_hdr_t *req;
2640 
2641 	ist = ict->ict_sess;
2642 
2643 	req = (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
2644 	if (req->opcode & ISCSI_OP_IMMEDIATE) {
2645 		/* no cmdsn increment for immediate PDUs */
2646 		return;
2647 	}
2648 
2649 	/* Ensure that the ExpCmdSN advances in an orderly manner */
2650 	mutex_enter(&ist->ist_sn_mutex);
2651 	ist->ist_expcmdsn = ntohl(req->cmdsn) + 1;
2652 	ist->ist_maxcmdsn = ntohl(req->cmdsn) + iscsit_cmd_window();
2653 	mutex_exit(&ist->ist_sn_mutex);
2654 }
2655 
2656 /*
2657  * Wrapper funtion, calls iscsi_calc_rspsn and idm_pdu_tx
2658  */
2659 void
2660 iscsit_pdu_tx(idm_pdu_t *pdu)
2661 {
2662 	iscsit_conn_t *ict = pdu->isp_ic->ic_handle;
2663 	iscsi_scsi_rsp_hdr_t *rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
2664 	iscsit_sess_t *ist = ict->ict_sess;
2665 
2666 	/*
2667 	 * The command sequence numbers are session-wide and must stay
2668 	 * consistent across the transfer, so protect the cmdsn with a
2669 	 * mutex lock on the session. The status sequence number will
2670 	 * be updated just before the transport layer transmits the PDU.
2671 	 */
2672 
2673 	mutex_enter(&ict->ict_sess->ist_sn_mutex);
2674 	/* Set ExpCmdSN and MaxCmdSN */
2675 	rsp->maxcmdsn = htonl(ist->ist_maxcmdsn);
2676 	rsp->expcmdsn = htonl(ist->ist_expcmdsn);
2677 	idm_pdu_tx(pdu);
2678 	mutex_exit(&ict->ict_sess->ist_sn_mutex);
2679 }
2680 
2681 /*
2682  * Internal functions
2683  */
2684 
2685 void
2686 iscsit_send_async_event(iscsit_conn_t *ict, uint8_t event)
2687 {
2688 	idm_pdu_t		*abt;
2689 	iscsi_async_evt_hdr_t	*async_abt;
2690 
2691 	/*
2692 	 * Get a PDU to build the abort request.
2693 	 */
2694 	abt = idm_pdu_alloc(sizeof (iscsi_hdr_t), 0);
2695 	if (abt == NULL) {
2696 		idm_conn_event(ict->ict_ic, CE_TRANSPORT_FAIL, NULL);
2697 		return;
2698 	}
2699 
2700 	/*
2701 	 * A asynchronous message is sent by the target to request a logout.
2702 	 * The StatSN for the connection is advanced after the PDU is sent
2703 	 * to allow for initiator and target state synchronization.
2704 	 */
2705 	idm_pdu_init(abt, ict->ict_ic, NULL, NULL);
2706 	abt->isp_datalen = 0;
2707 	abt->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2708 
2709 	async_abt = (iscsi_async_evt_hdr_t *)abt->isp_hdr;
2710 	bzero(async_abt, sizeof (*async_abt));
2711 	async_abt->opcode = ISCSI_OP_ASYNC_EVENT;
2712 	async_abt->async_event = event;
2713 	async_abt->flags = ISCSI_FLAG_FINAL;
2714 	async_abt->rsvd4[0] = 0xff;
2715 	async_abt->rsvd4[1] = 0xff;
2716 	async_abt->rsvd4[2] = 0xff;
2717 	async_abt->rsvd4[3] = 0xff;
2718 
2719 	switch (event) {
2720 	case ISCSI_ASYNC_EVENT_REQUEST_LOGOUT:
2721 		async_abt->param3 = htons(IDM_LOGOUT_SECONDS);
2722 		break;
2723 	case ISCSI_ASYNC_EVENT_SCSI_EVENT:
2724 	case ISCSI_ASYNC_EVENT_DROPPING_CONNECTION:
2725 	case ISCSI_ASYNC_EVENT_DROPPING_ALL_CONNECTIONS:
2726 	case ISCSI_ASYNC_EVENT_PARAM_NEGOTIATION:
2727 	default:
2728 		ASSERT(0);
2729 	}
2730 
2731 	iscsit_pdu_tx(abt);
2732 }
2733 
2734 void
2735 iscsit_send_reject(iscsit_conn_t *ict, idm_pdu_t *rejected_pdu, uint8_t reason)
2736 {
2737 	idm_pdu_t		*reject_pdu;
2738 	iscsi_reject_rsp_hdr_t	*reject;
2739 
2740 	/*
2741 	 * Get a PDU to build the abort request.
2742 	 */
2743 	reject_pdu = idm_pdu_alloc(sizeof (iscsi_hdr_t),
2744 	    rejected_pdu->isp_hdrlen);
2745 	if (reject_pdu == NULL) {
2746 		idm_conn_event(ict->ict_ic, CE_TRANSPORT_FAIL, NULL);
2747 		return;
2748 	}
2749 	idm_pdu_init(reject_pdu, ict->ict_ic, NULL, NULL);
2750 	/* StatSN is advanced after a Reject PDU */
2751 	reject_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2752 	reject_pdu->isp_datalen = rejected_pdu->isp_hdrlen;
2753 	bcopy(rejected_pdu->isp_hdr, reject_pdu->isp_data,
2754 	    rejected_pdu->isp_hdrlen);
2755 
2756 	reject = (iscsi_reject_rsp_hdr_t *)reject_pdu->isp_hdr;
2757 	bzero(reject, sizeof (*reject));
2758 	reject->opcode = ISCSI_OP_REJECT_MSG;
2759 	reject->reason = reason;
2760 	reject->flags = ISCSI_FLAG_FINAL;
2761 	hton24(reject->dlength, rejected_pdu->isp_hdrlen);
2762 	reject->must_be_ff[0] = 0xff;
2763 	reject->must_be_ff[1] = 0xff;
2764 	reject->must_be_ff[2] = 0xff;
2765 	reject->must_be_ff[3] = 0xff;
2766 
2767 	iscsit_pdu_tx(reject_pdu);
2768 }
2769 
2770 
2771 static iscsit_task_t *
2772 iscsit_task_alloc(iscsit_conn_t *ict)
2773 {
2774 	iscsit_task_t *itask;
2775 	iscsit_buf_t *immed_ibuf;
2776 
2777 	/*
2778 	 * Possible items to pre-alloc if we cache iscsit_task_t's:
2779 	 *
2780 	 * Status PDU w/ sense buffer
2781 	 * stmf_data_buf_t for immediate data
2782 	 */
2783 	itask = kmem_alloc(sizeof (iscsit_task_t) + sizeof (iscsit_buf_t) +
2784 	    sizeof (stmf_data_buf_t), KM_NOSLEEP);
2785 	if (itask != NULL) {
2786 		mutex_init(&itask->it_mutex, NULL, MUTEX_DRIVER, NULL);
2787 		itask->it_aborted = itask->it_stmf_abort =
2788 		    itask->it_tm_task = 0;
2789 
2790 		immed_ibuf = (iscsit_buf_t *)(itask + 1);
2791 		bzero(immed_ibuf, sizeof (*immed_ibuf));
2792 		immed_ibuf->ibuf_is_immed = B_TRUE;
2793 		immed_ibuf->ibuf_stmf_buf = (stmf_data_buf_t *)(immed_ibuf + 1);
2794 
2795 		bzero(immed_ibuf->ibuf_stmf_buf, sizeof (stmf_data_buf_t));
2796 		immed_ibuf->ibuf_stmf_buf->db_port_private = immed_ibuf;
2797 		immed_ibuf->ibuf_stmf_buf->db_sglist_length = 1;
2798 		immed_ibuf->ibuf_stmf_buf->db_flags = DB_DIRECTION_FROM_RPORT |
2799 		    DB_DONT_CACHE;
2800 		itask->it_immed_data = immed_ibuf;
2801 		itask->it_idm_task = idm_task_alloc(ict->ict_ic);
2802 		if (itask->it_idm_task != NULL) {
2803 			itask->it_idm_task->idt_private = itask;
2804 			itask->it_ict = ict;
2805 			itask->it_ttt = itask->it_idm_task->idt_tt;
2806 			return (itask);
2807 		} else {
2808 			kmem_free(itask, sizeof (iscsit_task_t) +
2809 			    sizeof (iscsit_buf_t) + sizeof (stmf_data_buf_t));
2810 		}
2811 	}
2812 
2813 	return (NULL);
2814 }
2815 
2816 static void
2817 iscsit_task_free(iscsit_task_t *itask)
2818 {
2819 	idm_task_free(itask->it_idm_task);
2820 	mutex_destroy(&itask->it_mutex);
2821 	kmem_free(itask, sizeof (iscsit_task_t) +
2822 	    sizeof (iscsit_buf_t) + sizeof (stmf_data_buf_t));
2823 }
2824 
2825 static iscsit_task_t *
2826 iscsit_tm_task_alloc(iscsit_conn_t *ict)
2827 {
2828 	iscsit_task_t *itask;
2829 
2830 	itask = kmem_zalloc(sizeof (iscsit_task_t), KM_NOSLEEP);
2831 	if (itask != NULL) {
2832 		idm_conn_hold(ict->ict_ic);
2833 		mutex_init(&itask->it_mutex, NULL, MUTEX_DRIVER, NULL);
2834 		itask->it_aborted = itask->it_stmf_abort =
2835 		    itask->it_tm_responded = 0;
2836 		itask->it_tm_pdu = NULL;
2837 		itask->it_tm_task = 1;
2838 		itask->it_ict = ict;
2839 	}
2840 
2841 	return (itask);
2842 }
2843 
2844 static void
2845 iscsit_tm_task_free(iscsit_task_t *itask)
2846 {
2847 	/*
2848 	 * If we responded then the call to idm_pdu_complete will free the
2849 	 * PDU.  Otherwise we got aborted before the TM function could
2850 	 * complete and we need to free the PDU explicitly.
2851 	 */
2852 	if (itask->it_tm_pdu != NULL && !itask->it_tm_responded)
2853 		idm_pdu_free(itask->it_tm_pdu);
2854 	idm_conn_rele(itask->it_ict->ict_ic);
2855 	mutex_destroy(&itask->it_mutex);
2856 	kmem_free(itask, sizeof (iscsit_task_t));
2857 }
2858 
2859 static idm_status_t
2860 iscsit_task_start(iscsit_task_t *itask)
2861 {
2862 	iscsit_sess_t *ist = itask->it_ict->ict_sess;
2863 	avl_index_t		where;
2864 
2865 	/*
2866 	 * Sanity check the ITT and ensure that this task does not already
2867 	 * exist.  If not then add the task to the session task list.
2868 	 */
2869 	mutex_enter(&ist->ist_mutex);
2870 	mutex_enter(&itask->it_mutex);
2871 	itask->it_active = 1;
2872 	if (avl_find(&ist->ist_task_list, itask, &where) == NULL) {
2873 		/* New task, add to AVL */
2874 		avl_insert(&ist->ist_task_list, itask, where);
2875 		mutex_exit(&itask->it_mutex);
2876 		mutex_exit(&ist->ist_mutex);
2877 		return (IDM_STATUS_SUCCESS);
2878 	}
2879 	mutex_exit(&itask->it_mutex);
2880 	mutex_exit(&ist->ist_mutex);
2881 
2882 	return (IDM_STATUS_REJECT);
2883 }
2884 
2885 static void
2886 iscsit_task_done(iscsit_task_t *itask)
2887 {
2888 	iscsit_sess_t *ist = itask->it_ict->ict_sess;
2889 
2890 	mutex_enter(&ist->ist_mutex);
2891 	mutex_enter(&itask->it_mutex);
2892 	if (itask->it_active) {
2893 		avl_remove(&ist->ist_task_list, itask);
2894 		itask->it_active = 0;
2895 	}
2896 	mutex_exit(&itask->it_mutex);
2897 	mutex_exit(&ist->ist_mutex);
2898 }
2899 
2900 /*
2901  * iscsit status PDU cache
2902  */
2903 
2904 /*ARGSUSED*/
2905 static int
2906 iscsit_status_pdu_constructor(void *pdu_void, void *arg, int flags)
2907 {
2908 	idm_pdu_t *pdu = pdu_void;
2909 	iscsi_scsi_rsp_hdr_t *rsp;
2910 
2911 	bzero(pdu, sizeof (idm_pdu_t));
2912 	pdu->isp_callback = iscsit_send_good_status_done;
2913 	pdu->isp_magic = IDM_PDU_MAGIC;
2914 	pdu->isp_hdr = (iscsi_hdr_t *)(pdu + 1); /* Ptr arithmetic */
2915 	pdu->isp_hdrlen = sizeof (iscsi_hdr_t);
2916 
2917 	/* Setup status response */
2918 	rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
2919 	bzero(rsp, sizeof (*rsp));
2920 	rsp->opcode = ISCSI_OP_SCSI_RSP;
2921 	rsp->flags = ISCSI_FLAG_FINAL;
2922 	rsp->response = ISCSI_STATUS_CMD_COMPLETED;
2923 
2924 	return (0);
2925 }
2926 
2927 /*
2928  * iscsit private data handler
2929  */
2930 
2931 /*ARGSUSED*/
2932 static void
2933 iscsit_pp_cb(struct stmf_port_provider *pp, int cmd, void *arg, uint32_t flags)
2934 {
2935 	it_config_t		*cfg;
2936 	nvlist_t		*nvl;
2937 	iscsit_service_enabled_t	old_state;
2938 
2939 	if ((cmd != STMF_PROVIDER_DATA_UPDATED) || (arg == NULL)) {
2940 		return;
2941 	}
2942 
2943 	nvl = (nvlist_t *)arg;
2944 
2945 	/* Translate nvlist */
2946 	if (it_nv_to_config(nvl, &cfg) != 0) {
2947 		cmn_err(CE_WARN, "Configuration is invalid");
2948 		return;
2949 	}
2950 
2951 	/* Check that no iSCSI ioctl is currently running */
2952 	mutex_enter(&iscsit_global.global_state_mutex);
2953 	old_state = iscsit_global.global_svc_state;
2954 	switch (iscsit_global.global_svc_state) {
2955 	case ISE_ENABLED:
2956 	case ISE_DISABLED:
2957 		iscsit_global.global_svc_state = ISE_BUSY;
2958 		break;
2959 	case ISE_ENABLING:
2960 		/*
2961 		 * It is OK for the iscsit_pp_cb to be called from inside of
2962 		 * an iSCSI ioctl only if we are currently executing inside
2963 		 * of stmf_register_port_provider.
2964 		 */
2965 		ASSERT((flags & STMF_PCB_PREG_COMPLETE) != 0);
2966 		break;
2967 	default:
2968 		cmn_err(CE_WARN, "iscsit_pp_cb called when global_svc_state"
2969 		    " is not ENABLED(0x%x) -- ignoring",
2970 		    iscsit_global.global_svc_state);
2971 		mutex_exit(&iscsit_global.global_state_mutex);
2972 		it_config_free_cmn(cfg);
2973 		return;
2974 	}
2975 	mutex_exit(&iscsit_global.global_state_mutex);
2976 
2977 	/* Update config */
2978 	(void) iscsit_config_merge(cfg);
2979 
2980 	it_config_free_cmn(cfg);
2981 
2982 	/* Restore old iSCSI driver global state */
2983 	mutex_enter(&iscsit_global.global_state_mutex);
2984 	ASSERT(iscsit_global.global_svc_state == ISE_BUSY ||
2985 	    iscsit_global.global_svc_state == ISE_ENABLING);
2986 	iscsit_global.global_svc_state = old_state;
2987 	mutex_exit(&iscsit_global.global_state_mutex);
2988 }
2989 
2990 
2991 static it_cfg_status_t
2992 iscsit_config_merge(it_config_t *in_cfg)
2993 {
2994 	it_cfg_status_t	status;
2995 	it_config_t	*cfg;
2996 	it_config_t	tmp_cfg;
2997 	list_t		tpg_del_list;
2998 
2999 	if (in_cfg) {
3000 		cfg = in_cfg;
3001 	} else {
3002 		/* Make empty config */
3003 		bzero(&tmp_cfg, sizeof (tmp_cfg));
3004 		cfg = &tmp_cfg;
3005 	}
3006 
3007 	list_create(&tpg_del_list,  sizeof (iscsit_tpg_t),
3008 	    offsetof(iscsit_tpg_t, tpg_delete_ln));
3009 
3010 	/*
3011 	 * Update targets, initiator contexts, target portal groups,
3012 	 * and iSNS client
3013 	 */
3014 	ISCSIT_GLOBAL_LOCK(RW_WRITER);
3015 	if (((status = iscsit_config_merge_tpg(cfg, &tpg_del_list))
3016 	    != 0) ||
3017 	    ((status = iscsit_config_merge_tgt(cfg)) != 0) ||
3018 	    ((status = iscsit_config_merge_ini(cfg)) != 0) ||
3019 	    ((status = isnst_config_merge(cfg)) != 0)) {
3020 		ISCSIT_GLOBAL_UNLOCK();
3021 		return (status);
3022 	}
3023 
3024 	/* Update other global config parameters */
3025 	if (iscsit_global.global_props) {
3026 		nvlist_free(iscsit_global.global_props);
3027 		iscsit_global.global_props = NULL;
3028 	}
3029 	if (in_cfg) {
3030 		(void) nvlist_dup(cfg->config_global_properties,
3031 		    &iscsit_global.global_props, KM_SLEEP);
3032 	}
3033 	ISCSIT_GLOBAL_UNLOCK();
3034 
3035 	iscsit_config_destroy_tpgs(&tpg_del_list);
3036 
3037 	list_destroy(&tpg_del_list);
3038 
3039 	return (ITCFG_SUCCESS);
3040 }
3041 
3042 /*
3043  * iscsit_sna_lt[e]
3044  *
3045  * Compare serial numbers using serial number arithmetic as defined in
3046  * RFC 1982.
3047  *
3048  * NOTE: This code is duplicated in the isns server. It ought to be common.
3049  */
3050 
3051 static int
3052 iscsit_sna_lt(uint32_t sn1, uint32_t sn2)
3053 {
3054 	return ((sn1 != sn2) &&
3055 	    (((sn1 < sn2) && ((sn2 - sn1) < ISCSIT_SNA32_CHECK)) ||
3056 	    ((sn1 > sn2) && ((sn1 - sn2) > ISCSIT_SNA32_CHECK))));
3057 }
3058 
3059 static int
3060 iscsit_sna_lte(uint32_t sn1, uint32_t sn2)
3061 {
3062 	return ((sn1 == sn2) ||
3063 	    (((sn1 < sn2) && ((sn2 - sn1) < ISCSIT_SNA32_CHECK)) ||
3064 	    ((sn1 > sn2) && ((sn1 - sn2) > ISCSIT_SNA32_CHECK))));
3065 }
3066 
3067 
3068 static boolean_t
3069 iscsit_cmdsn_in_window(iscsit_conn_t *ict, uint32_t cmdsn)
3070 {
3071 	iscsit_sess_t	*ist = ict->ict_sess;
3072 	int		rval = B_TRUE;
3073 
3074 	ist = ict->ict_sess;
3075 
3076 	mutex_enter(&ist->ist_sn_mutex);
3077 
3078 	/*
3079 	 * If cmdsn is less than ist_expcmdsn - iscsit_cmd_window() or
3080 	 * greater than ist_expcmdsn, it's not in the window.
3081 	 */
3082 
3083 	if (iscsit_sna_lt(cmdsn, (ist->ist_expcmdsn - iscsit_cmd_window())) ||
3084 	    !iscsit_sna_lte(cmdsn, ist->ist_expcmdsn)) {
3085 		rval = B_FALSE;
3086 	}
3087 
3088 	mutex_exit(&ist->ist_sn_mutex);
3089 
3090 	return (rval);
3091 }
3092 
3093 /*
3094  * iscsit_check_cmdsn_and_queue
3095  *
3096  * Independent of the order in which the iSCSI target receives non-immediate
3097  * command PDU across the entire session and any multiple connections within
3098  * the session, the target must deliver the commands to the SCSI layer in
3099  * CmdSN order. So out-of-order non-immediate commands are queued up on a
3100  * session-wide wait queue. Duplicate commands are ignored.
3101  *
3102  */
3103 static int
3104 iscsit_check_cmdsn_and_queue(idm_pdu_t *rx_pdu)
3105 {
3106 	idm_conn_t		*ic = rx_pdu->isp_ic;
3107 	iscsit_conn_t		*ict = ic->ic_handle;
3108 	iscsit_sess_t		*ist = ict->ict_sess;
3109 	iscsi_scsi_cmd_hdr_t	*hdr = (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
3110 
3111 	mutex_enter(&ist->ist_sn_mutex);
3112 	if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
3113 		/* do not queue, handle it immediately */
3114 		DTRACE_PROBE2(immediate__cmd, iscsit_sess_t *, ist,
3115 		    idm_pdu_t *, rx_pdu);
3116 		mutex_exit(&ist->ist_sn_mutex);
3117 		return (ISCSIT_CMDSN_EQ_EXPCMDSN);
3118 	}
3119 	if (iscsit_sna_lt(ist->ist_expcmdsn, ntohl(hdr->cmdsn))) {
3120 		/*
3121 		 * Out-of-order commands (cmdSN higher than ExpCmdSN)
3122 		 * are staged on a fixed-size circular buffer until
3123 		 * the missing command is delivered to the SCSI layer.
3124 		 * Irrespective of the order of insertion into the
3125 		 * staging queue, the commands are processed out of the
3126 		 * queue in cmdSN order only.
3127 		 */
3128 		rx_pdu->isp_queue_time = ddi_get_time();
3129 		iscsit_add_pdu_to_queue(ist, rx_pdu);
3130 		mutex_exit(&ist->ist_sn_mutex);
3131 		return (ISCSIT_CMDSN_GT_EXPCMDSN);
3132 	} else if (iscsit_sna_lt(ntohl(hdr->cmdsn), ist->ist_expcmdsn)) {
3133 		DTRACE_PROBE3(cmdsn__lt__expcmdsn, iscsit_sess_t *, ist,
3134 		    iscsit_conn_t *, ict, idm_pdu_t *, rx_pdu);
3135 		mutex_exit(&ist->ist_sn_mutex);
3136 		return (ISCSIT_CMDSN_LT_EXPCMDSN);
3137 	} else {
3138 		mutex_exit(&ist->ist_sn_mutex);
3139 		return (ISCSIT_CMDSN_EQ_EXPCMDSN);
3140 	}
3141 }
3142 
3143 /*
3144  * iscsit_add_pdu_to_queue() adds PDUs into the array indexed by
3145  * their cmdsn value. The length of the array is kept above the
3146  * maximum window size. The window keeps the cmdsn within a range
3147  * such that there are no collisons. e.g. the assumption is that
3148  * the windowing checks make it impossible to receive PDUs that
3149  * index into the same location in the array.
3150  */
3151 static void
3152 iscsit_add_pdu_to_queue(iscsit_sess_t *ist, idm_pdu_t *rx_pdu)
3153 {
3154 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3155 	iscsit_conn_t	*ict 	= rx_pdu->isp_ic->ic_handle;
3156 	uint32_t	cmdsn	=
3157 	    ((iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr)->cmdsn;
3158 	uint32_t	index;
3159 
3160 	ASSERT(MUTEX_HELD(&ist->ist_sn_mutex));
3161 	/*
3162 	 * If the connection is being torn down, then
3163 	 * don't add the PDU to the staging queue
3164 	 */
3165 	mutex_enter(&ict->ict_mutex);
3166 	if (ict->ict_lost) {
3167 		mutex_exit(&ict->ict_mutex);
3168 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
3169 		return;
3170 	}
3171 	iscsit_conn_dispatch_hold(ict);
3172 	mutex_exit(&ict->ict_mutex);
3173 
3174 	index = ntohl(cmdsn) % ISCSIT_RXPDU_QUEUE_LEN;
3175 	/*
3176 	 * In the normal case, assuming that the Initiator is not
3177 	 * buggy and that we don't have packet duplication occuring,
3178 	 * the entry in the array will be NULL.  However, we may have
3179 	 * received a duplicate PDU with cmdsn > expsn , and in that
3180 	 * case we just ignore this PDU -- the previously received one
3181 	 * remains queued for processing.  We need to be careful not
3182 	 * to leak this one however.
3183 	 */
3184 	if (cbuf->cb_buffer[index] != NULL) {
3185 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
3186 	} else {
3187 		cbuf->cb_buffer[index] = rx_pdu;
3188 		cbuf->cb_num_elems++;
3189 	}
3190 }
3191 
3192 static idm_pdu_t *
3193 iscsit_remove_pdu_from_queue(iscsit_sess_t *ist, uint32_t cmdsn)
3194 {
3195 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3196 	idm_pdu_t	*pdu	= NULL;
3197 	uint32_t	index;
3198 
3199 	ASSERT(MUTEX_HELD(&ist->ist_sn_mutex));
3200 	index = cmdsn % ISCSIT_RXPDU_QUEUE_LEN;
3201 	if ((pdu = cbuf->cb_buffer[index]) != NULL) {
3202 		ASSERT(cmdsn ==
3203 		    ntohl(((iscsi_scsi_cmd_hdr_t *)pdu->isp_hdr)->cmdsn));
3204 		cbuf->cb_buffer[index] = NULL;
3205 		cbuf->cb_num_elems--;
3206 		return (pdu);
3207 	}
3208 	return (NULL);
3209 }
3210 
3211 /*
3212  * iscsit_process_pdu_in_queue() finds the next pdu in sequence
3213  * and posts it to the SCSI layer
3214  */
3215 static void
3216 iscsit_process_pdu_in_queue(iscsit_sess_t *ist)
3217 {
3218 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3219 	idm_pdu_t	*pdu = NULL;
3220 	uint32_t	expcmdsn;
3221 
3222 	for (;;) {
3223 		mutex_enter(&ist->ist_sn_mutex);
3224 		if (cbuf->cb_num_elems == 0) {
3225 			mutex_exit(&ist->ist_sn_mutex);
3226 			break;
3227 		}
3228 		expcmdsn = ist->ist_expcmdsn;
3229 		if ((pdu = iscsit_remove_pdu_from_queue(ist, expcmdsn))
3230 		    == NULL) {
3231 			mutex_exit(&ist->ist_sn_mutex);
3232 			break;
3233 		}
3234 		mutex_exit(&ist->ist_sn_mutex);
3235 		iscsit_post_staged_pdu(pdu);
3236 	}
3237 }
3238 
3239 static void
3240 iscsit_post_staged_pdu(idm_pdu_t *rx_pdu)
3241 {
3242 	iscsit_conn_t	*ict	= rx_pdu->isp_ic->ic_handle;
3243 
3244 	/* Post the PDU to the SCSI layer */
3245 	switch (IDM_PDU_OPCODE(rx_pdu)) {
3246 	case ISCSI_OP_NOOP_OUT:
3247 		iscsit_set_cmdsn(ict, rx_pdu);
3248 		iscsit_pdu_op_noop(ict, rx_pdu);
3249 		break;
3250 	case ISCSI_OP_TEXT_CMD:
3251 		iscsit_set_cmdsn(ict, rx_pdu);
3252 		iscsit_pdu_op_text_cmd(ict, rx_pdu);
3253 		break;
3254 	case ISCSI_OP_SCSI_TASK_MGT_MSG:
3255 		iscsit_set_cmdsn(ict, rx_pdu);
3256 		iscsit_op_scsi_task_mgmt(ict, rx_pdu);
3257 		break;
3258 	case ISCSI_OP_SCSI_CMD:
3259 		/* cmdSN will be incremented after creating itask */
3260 		iscsit_post_scsi_cmd(rx_pdu->isp_ic, rx_pdu);
3261 		break;
3262 	case ISCSI_OP_LOGOUT_CMD:
3263 		iscsit_set_cmdsn(ict, rx_pdu);
3264 		iscsit_pdu_op_logout_cmd(ict, rx_pdu);
3265 		break;
3266 	default:
3267 		/* No other PDUs should be placed on the queue */
3268 		ASSERT(0);
3269 	}
3270 	iscsit_conn_dispatch_rele(ict); /* release hold on the conn */
3271 }
3272 
3273 /* ARGSUSED */
3274 void
3275 iscsit_rxpdu_queue_monitor_start(void)
3276 {
3277 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3278 	if (iscsit_rxpdu_queue_monitor_thr_running) {
3279 		mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3280 		return;
3281 	}
3282 	iscsit_rxpdu_queue_monitor_thr_id =
3283 	    thread_create(NULL, 0, iscsit_rxpdu_queue_monitor, NULL,
3284 	    0, &p0, TS_RUN, minclsyspri);
3285 	while (!iscsit_rxpdu_queue_monitor_thr_running) {
3286 		cv_wait(&iscsit_rxpdu_queue_monitor_cv,
3287 		    &iscsit_rxpdu_queue_monitor_mutex);
3288 	}
3289 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3290 
3291 }
3292 
3293 /* ARGSUSED */
3294 void
3295 iscsit_rxpdu_queue_monitor_stop(void)
3296 {
3297 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3298 	if (iscsit_rxpdu_queue_monitor_thr_running) {
3299 		iscsit_rxpdu_queue_monitor_thr_running = B_FALSE;
3300 		cv_signal(&iscsit_rxpdu_queue_monitor_cv);
3301 		mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3302 
3303 		thread_join(iscsit_rxpdu_queue_monitor_thr_did);
3304 		return;
3305 	}
3306 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3307 }
3308 
3309 /*
3310  * A separate thread is used to scan the staging queue on all the
3311  * sessions, If a delayed PDU does not arrive within a timeout, the
3312  * target will advance to the staged PDU that is next in sequence
3313  * and exceeded the threshold wait time. It is up to the initiator
3314  * to note that the target has not acknowledged a particular cmdsn
3315  * and take appropriate action.
3316  */
3317 /* ARGSUSED */
3318 static void
3319 iscsit_rxpdu_queue_monitor(void *arg)
3320 {
3321 	iscsit_tgt_t	*tgt;
3322 	iscsit_sess_t	*ist;
3323 
3324 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3325 	iscsit_rxpdu_queue_monitor_thr_did = curthread->t_did;
3326 	iscsit_rxpdu_queue_monitor_thr_running = B_TRUE;
3327 	cv_signal(&iscsit_rxpdu_queue_monitor_cv);
3328 
3329 	while (iscsit_rxpdu_queue_monitor_thr_running) {
3330 		ISCSIT_GLOBAL_LOCK(RW_READER);
3331 		for (tgt = avl_first(&iscsit_global.global_target_list);
3332 		    tgt != NULL;
3333 		    tgt = AVL_NEXT(&iscsit_global.global_target_list, tgt)) {
3334 			mutex_enter(&tgt->target_mutex);
3335 			for (ist = avl_first(&tgt->target_sess_list);
3336 			    ist != NULL;
3337 			    ist = AVL_NEXT(&tgt->target_sess_list, ist)) {
3338 
3339 				iscsit_rxpdu_queue_monitor_session(ist);
3340 			}
3341 			mutex_exit(&tgt->target_mutex);
3342 		}
3343 		ISCSIT_GLOBAL_UNLOCK();
3344 		if (iscsit_rxpdu_queue_monitor_thr_running == B_FALSE) {
3345 			break;
3346 		}
3347 		(void) cv_reltimedwait(&iscsit_rxpdu_queue_monitor_cv,
3348 		    &iscsit_rxpdu_queue_monitor_mutex,
3349 		    ISCSIT_RXPDU_QUEUE_MONITOR_INTERVAL * drv_usectohz(1000000),
3350 		    TR_CLOCK_TICK);
3351 	}
3352 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3353 	thread_exit();
3354 }
3355 
3356 static void
3357 iscsit_rxpdu_queue_monitor_session(iscsit_sess_t *ist)
3358 {
3359 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3360 	idm_pdu_t	*next_pdu = NULL;
3361 	uint32_t	index, next_cmdsn, i;
3362 
3363 	/*
3364 	 * Assume that all PDUs in the staging queue have a cmdsn >= expcmdsn.
3365 	 * Starting with the expcmdsn, iterate over the staged PDUs to find
3366 	 * the next PDU with a wait time greater than the threshold. If found
3367 	 * advance the staged PDU to the SCSI layer, skipping over the missing
3368 	 * PDU(s) to get past the hole in the command sequence. It is up to
3369 	 * the initiator to note that the target has not acknowledged a cmdsn
3370 	 * and take appropriate action.
3371 	 *
3372 	 * Since the PDU(s) arrive in any random order, it is possible that
3373 	 * that the actual wait time for a particular PDU is much longer than
3374 	 * the defined threshold. e.g. Consider a case where commands are sent
3375 	 * over 4 different connections, and cmdsn = 1004 arrives first, then
3376 	 * 1003, and 1002 and 1001 are lost due to a connection failure.
3377 	 * So now 1003 is waiting for 1002 to be delivered, and although the
3378 	 * wait time of 1004 > wait time of 1003, only 1003 will be considered
3379 	 * by the monitor thread. 1004 will be automatically processed by
3380 	 * iscsit_process_pdu_in_queue() once the scan is complete and the
3381 	 * expcmdsn becomes current.
3382 	 */
3383 	mutex_enter(&ist->ist_sn_mutex);
3384 	cbuf = ist->ist_rxpdu_queue;
3385 	if (cbuf->cb_num_elems == 0) {
3386 		mutex_exit(&ist->ist_sn_mutex);
3387 		return;
3388 	}
3389 	for (next_pdu = NULL, i = 0; ; i++) {
3390 		next_cmdsn = ist->ist_expcmdsn + i; /* start at expcmdsn */
3391 		index = next_cmdsn % ISCSIT_RXPDU_QUEUE_LEN;
3392 		if ((next_pdu = cbuf->cb_buffer[index]) != NULL) {
3393 			/*
3394 			 * If the PDU wait time has not exceeded threshold
3395 			 * stop scanning the staging queue until the timer
3396 			 * fires again
3397 			 */
3398 			if ((ddi_get_time() - next_pdu->isp_queue_time)
3399 			    < rxpdu_queue_threshold) {
3400 				mutex_exit(&ist->ist_sn_mutex);
3401 				return;
3402 			}
3403 			/*
3404 			 * Remove the next PDU from the queue and post it
3405 			 * to the SCSI layer, skipping over the missing
3406 			 * PDU. Stop scanning the staging queue until
3407 			 * the monitor timer fires again
3408 			 */
3409 			(void) iscsit_remove_pdu_from_queue(ist, next_cmdsn);
3410 			mutex_exit(&ist->ist_sn_mutex);
3411 			DTRACE_PROBE3(advanced__to__blocked__cmdsn,
3412 			    iscsit_sess_t *, ist, idm_pdu_t *, next_pdu,
3413 			    uint32_t, next_cmdsn);
3414 			iscsit_post_staged_pdu(next_pdu);
3415 			/* Deliver any subsequent PDUs immediately */
3416 			iscsit_process_pdu_in_queue(ist);
3417 			return;
3418 		}
3419 		/*
3420 		 * Skipping over i PDUs, e.g. a case where commands 1001 and
3421 		 * 1002 are lost in the network, skip over both and post 1003
3422 		 * expcmdsn then becomes 1004 at the end of the scan.
3423 		 */
3424 		DTRACE_PROBE2(skipping__over__cmdsn, iscsit_sess_t *, ist,
3425 		    uint32_t, next_cmdsn);
3426 	}
3427 	/*
3428 	 * following the assumption, staged cmdsn >= expcmdsn, this statement
3429 	 * is never reached.
3430 	 */
3431 }
3432