xref: /onnv-gate/usr/src/uts/common/io/comstar/port/iscsit/iscsit.c (revision 12571:05943d9c379f)
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 
25 #include <sys/cpuvar.h>
26 #include <sys/types.h>
27 #include <sys/conf.h>
28 #include <sys/stat.h>
29 #include <sys/file.h>
30 #include <sys/ddi.h>
31 #include <sys/sunddi.h>
32 #include <sys/modctl.h>
33 #include <sys/sysmacros.h>
34 #include <sys/socket.h>
35 #include <sys/strsubr.h>
36 #include <sys/nvpair.h>
37 
38 #include <sys/stmf.h>
39 #include <sys/stmf_ioctl.h>
40 #include <sys/portif.h>
41 #include <sys/idm/idm.h>
42 #include <sys/idm/idm_conn_sm.h>
43 
44 #include "iscsit_isns.h"
45 #include "iscsit.h"
46 
47 #define	ISCSIT_VERSION		BUILD_DATE "-1.18dev"
48 #define	ISCSIT_NAME_VERSION	"COMSTAR ISCSIT v" ISCSIT_VERSION
49 
50 /*
51  * DDI entry points.
52  */
53 static int iscsit_drv_attach(dev_info_t *, ddi_attach_cmd_t);
54 static int iscsit_drv_detach(dev_info_t *, ddi_detach_cmd_t);
55 static int iscsit_drv_getinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
56 static int iscsit_drv_open(dev_t *, int, int, cred_t *);
57 static int iscsit_drv_close(dev_t, int, int, cred_t *);
58 static boolean_t iscsit_drv_busy(void);
59 static int iscsit_drv_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);
60 
61 extern struct mod_ops mod_miscops;
62 
63 
64 static struct cb_ops iscsit_cb_ops = {
65 	iscsit_drv_open,	/* cb_open */
66 	iscsit_drv_close,	/* cb_close */
67 	nodev,			/* cb_strategy */
68 	nodev,			/* cb_print */
69 	nodev,			/* cb_dump */
70 	nodev,			/* cb_read */
71 	nodev,			/* cb_write */
72 	iscsit_drv_ioctl,	/* cb_ioctl */
73 	nodev,			/* cb_devmap */
74 	nodev,			/* cb_mmap */
75 	nodev,			/* cb_segmap */
76 	nochpoll,		/* cb_chpoll */
77 	ddi_prop_op,		/* cb_prop_op */
78 	NULL,			/* cb_streamtab */
79 	D_MP,			/* cb_flag */
80 	CB_REV,			/* cb_rev */
81 	nodev,			/* cb_aread */
82 	nodev,			/* cb_awrite */
83 };
84 
85 static struct dev_ops iscsit_dev_ops = {
86 	DEVO_REV,		/* devo_rev */
87 	0,			/* devo_refcnt */
88 	iscsit_drv_getinfo,	/* devo_getinfo */
89 	nulldev,		/* devo_identify */
90 	nulldev,		/* devo_probe */
91 	iscsit_drv_attach,	/* devo_attach */
92 	iscsit_drv_detach,	/* devo_detach */
93 	nodev,			/* devo_reset */
94 	&iscsit_cb_ops,		/* devo_cb_ops */
95 	NULL,			/* devo_bus_ops */
96 	NULL,			/* devo_power */
97 	ddi_quiesce_not_needed,	/* quiesce */
98 };
99 
100 static struct modldrv modldrv = {
101 	&mod_driverops,
102 	"iSCSI Target",
103 	&iscsit_dev_ops,
104 };
105 
106 static struct modlinkage modlinkage = {
107 	MODREV_1,
108 	&modldrv,
109 	NULL,
110 };
111 
112 
113 iscsit_global_t iscsit_global;
114 
115 kmem_cache_t	*iscsit_status_pdu_cache;
116 
117 boolean_t	iscsit_sm_logging = B_FALSE;
118 
119 static idm_status_t iscsit_init(dev_info_t *dip);
120 static idm_status_t iscsit_enable_svc(iscsit_hostinfo_t *hostinfo);
121 static void iscsit_disable_svc(void);
122 
123 static int
124 iscsit_check_cmdsn_and_queue(idm_pdu_t *rx_pdu);
125 
126 static void
127 iscsit_add_pdu_to_queue(iscsit_sess_t *ist, idm_pdu_t *rx_pdu);
128 
129 static idm_pdu_t *
130 iscsit_remove_pdu_from_queue(iscsit_sess_t *ist, uint32_t cmdsn);
131 
132 static void
133 iscsit_process_pdu_in_queue(iscsit_sess_t *ist);
134 
135 static void
136 iscsit_rxpdu_queue_monitor_session(iscsit_sess_t *ist);
137 
138 static void
139 iscsit_rxpdu_queue_monitor(void *arg);
140 
141 static void
142 iscsit_post_staged_pdu(idm_pdu_t *rx_pdu);
143 
144 static void
145 iscsit_post_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu);
146 
147 static void
148 iscsit_op_scsi_task_mgmt(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
149 
150 static void
151 iscsit_pdu_op_noop(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
152 
153 static void
154 iscsit_pdu_op_login_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
155 
156 void
157 iscsit_pdu_op_text_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
158 
159 static void
160 iscsit_pdu_op_logout_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
161 
162 int iscsit_cmd_window();
163 
164 static  int
165 iscsit_sna_lt(uint32_t sn1, uint32_t sn2);
166 
167 void
168 iscsit_set_cmdsn(iscsit_conn_t *ict, idm_pdu_t *rx_pdu);
169 
170 static void
171 iscsit_deferred_dispatch(idm_pdu_t *rx_pdu);
172 
173 static void
174 iscsit_deferred(void *rx_pdu_void);
175 
176 static idm_status_t
177 iscsit_conn_accept(idm_conn_t *ic);
178 
179 static idm_status_t
180 iscsit_ffp_enabled(idm_conn_t *ic);
181 
182 static idm_status_t
183 iscsit_ffp_disabled(idm_conn_t *ic, idm_ffp_disable_t disable_class);
184 
185 static idm_status_t
186 iscsit_conn_lost(idm_conn_t *ic);
187 
188 static idm_status_t
189 iscsit_conn_destroy(idm_conn_t *ic);
190 
191 static stmf_data_buf_t *
192 iscsit_dbuf_alloc(scsi_task_t *task, uint32_t size, uint32_t *pminsize,
193     uint32_t flags);
194 
195 static void
196 iscsit_dbuf_free(stmf_dbuf_store_t *ds, stmf_data_buf_t *dbuf);
197 
198 static void
199 iscsit_buf_xfer_cb(idm_buf_t *idb, idm_status_t status);
200 
201 static void
202 iscsit_send_good_status_done(idm_pdu_t *pdu, idm_status_t status);
203 
204 static void
205 iscsit_send_status_done(idm_pdu_t *pdu, idm_status_t status);
206 
207 static stmf_status_t
208 iscsit_idm_to_stmf(idm_status_t idmrc);
209 
210 static iscsit_task_t *
211 iscsit_task_alloc(iscsit_conn_t *ict);
212 
213 static void
214 iscsit_task_free(iscsit_task_t *itask);
215 
216 static iscsit_task_t *
217 iscsit_tm_task_alloc(iscsit_conn_t *ict);
218 
219 static void
220 iscsit_tm_task_free(iscsit_task_t *itask);
221 
222 static idm_status_t
223 iscsit_task_start(iscsit_task_t *itask);
224 
225 static void
226 iscsit_task_done(iscsit_task_t *itask);
227 
228 static int
229 iscsit_status_pdu_constructor(void *pdu_void, void *arg, int flags);
230 
231 static void
232 iscsit_pp_cb(struct stmf_port_provider *pp, int cmd, void *arg, uint32_t flags);
233 
234 static it_cfg_status_t
235 iscsit_config_merge(it_config_t *cfg);
236 
237 static idm_status_t
238 iscsit_login_fail(idm_conn_t *ic);
239 
240 static boolean_t iscsit_cmdsn_in_window(iscsit_conn_t *ict, uint32_t cmdsn);
241 static void iscsit_send_direct_scsi_resp(iscsit_conn_t *ict, idm_pdu_t *rx_pdu,
242     uint8_t response, uint8_t cmd_status);
243 static void iscsit_send_task_mgmt_resp(idm_pdu_t *tm_resp_pdu,
244     uint8_t tm_status);
245 
246 /*
247  * MC/S: Out-of-order commands are staged on a session-wide wait
248  * queue until a system-tunable threshold is reached. A separate
249  * thread is used to scan the staging queue on all the session,
250  * If a delayed PDU does not arrive within a timeout, the target
251  * will advance to the staged PDU that is next in sequence, skipping
252  * over the missing PDU(s) to go past a hole in the sequence.
253  */
254 volatile int rxpdu_queue_threshold = ISCSIT_RXPDU_QUEUE_THRESHOLD;
255 
256 static kmutex_t		iscsit_rxpdu_queue_monitor_mutex;
257 kthread_t		*iscsit_rxpdu_queue_monitor_thr_id;
258 static kt_did_t		iscsit_rxpdu_queue_monitor_thr_did;
259 static boolean_t	iscsit_rxpdu_queue_monitor_thr_running;
260 static kcondvar_t	iscsit_rxpdu_queue_monitor_cv;
261 
262 int
263 _init(void)
264 {
265 	int rc;
266 
267 	rw_init(&iscsit_global.global_rwlock, NULL, RW_DRIVER, NULL);
268 	mutex_init(&iscsit_global.global_state_mutex, NULL,
269 	    MUTEX_DRIVER, NULL);
270 	iscsit_global.global_svc_state = ISE_DETACHED;
271 
272 	mutex_init(&iscsit_rxpdu_queue_monitor_mutex, NULL,
273 	    MUTEX_DRIVER, NULL);
274 	iscsit_rxpdu_queue_monitor_thr_id = NULL;
275 	iscsit_rxpdu_queue_monitor_thr_running = B_FALSE;
276 	cv_init(&iscsit_rxpdu_queue_monitor_cv, NULL, CV_DEFAULT, NULL);
277 
278 	if ((rc = mod_install(&modlinkage)) != 0) {
279 		mutex_destroy(&iscsit_global.global_state_mutex);
280 		rw_destroy(&iscsit_global.global_rwlock);
281 		return (rc);
282 	}
283 
284 	return (rc);
285 }
286 
287 int
288 _info(struct modinfo *modinfop)
289 {
290 	return (mod_info(&modlinkage, modinfop));
291 }
292 
293 int
294 _fini(void)
295 {
296 	int rc;
297 
298 	rc = mod_remove(&modlinkage);
299 
300 	if (rc == 0) {
301 		mutex_destroy(&iscsit_rxpdu_queue_monitor_mutex);
302 		cv_destroy(&iscsit_rxpdu_queue_monitor_cv);
303 		mutex_destroy(&iscsit_global.global_state_mutex);
304 		rw_destroy(&iscsit_global.global_rwlock);
305 	}
306 
307 	return (rc);
308 }
309 
310 /*
311  * DDI entry points.
312  */
313 
314 /* ARGSUSED */
315 static int
316 iscsit_drv_getinfo(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg,
317     void **result)
318 {
319 	ulong_t instance = getminor((dev_t)arg);
320 
321 	switch (cmd) {
322 	case DDI_INFO_DEVT2DEVINFO:
323 		*result = iscsit_global.global_dip;
324 		return (DDI_SUCCESS);
325 
326 	case DDI_INFO_DEVT2INSTANCE:
327 		*result = (void *)instance;
328 		return (DDI_SUCCESS);
329 
330 	default:
331 		break;
332 	}
333 
334 	return (DDI_FAILURE);
335 }
336 
337 static int
338 iscsit_drv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
339 {
340 	if (cmd != DDI_ATTACH) {
341 		return (DDI_FAILURE);
342 	}
343 
344 	if (ddi_get_instance(dip) != 0) {
345 		/* we only allow instance 0 to attach */
346 		return (DDI_FAILURE);
347 	}
348 
349 	/* create the minor node */
350 	if (ddi_create_minor_node(dip, ISCSIT_MODNAME, S_IFCHR, 0,
351 	    DDI_PSEUDO, 0) != DDI_SUCCESS) {
352 		cmn_err(CE_WARN, "iscsit_drv_attach: "
353 		    "failed creating minor node");
354 		return (DDI_FAILURE);
355 	}
356 
357 	if (iscsit_init(dip) != IDM_STATUS_SUCCESS) {
358 		cmn_err(CE_WARN, "iscsit_drv_attach: "
359 		    "failed to initialize");
360 		ddi_remove_minor_node(dip, NULL);
361 		return (DDI_FAILURE);
362 	}
363 
364 	iscsit_global.global_svc_state = ISE_DISABLED;
365 	iscsit_global.global_dip = dip;
366 
367 	return (DDI_SUCCESS);
368 }
369 
370 /*ARGSUSED*/
371 static int
372 iscsit_drv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
373 {
374 	if (cmd != DDI_DETACH)
375 		return (DDI_FAILURE);
376 
377 	/*
378 	 * drv_detach is called in a context that owns the
379 	 * device node for the /dev/pseudo device.  If this thread blocks
380 	 * for any resource, other threads that need the /dev/pseudo device
381 	 * may end up in a deadlock with this thread.Hence, we use a
382 	 * separate lock just for the structures that drv_detach needs
383 	 * to access.
384 	 */
385 	mutex_enter(&iscsit_global.global_state_mutex);
386 	if (iscsit_drv_busy()) {
387 		mutex_exit(&iscsit_global.global_state_mutex);
388 		return (EBUSY);
389 	}
390 
391 	iscsit_global.global_dip = NULL;
392 	ddi_remove_minor_node(dip, NULL);
393 
394 	ldi_ident_release(iscsit_global.global_li);
395 	iscsit_global.global_svc_state = ISE_DETACHED;
396 
397 	mutex_exit(&iscsit_global.global_state_mutex);
398 
399 	return (DDI_SUCCESS);
400 }
401 
402 /*ARGSUSED*/
403 static int
404 iscsit_drv_open(dev_t *devp, int flag, int otyp, cred_t *credp)
405 {
406 	return (0);
407 }
408 
409 /* ARGSUSED */
410 static int
411 iscsit_drv_close(dev_t dev, int flag, int otyp, cred_t *credp)
412 {
413 	return (0);
414 }
415 
416 static boolean_t
417 iscsit_drv_busy(void)
418 {
419 	ASSERT(MUTEX_HELD(&iscsit_global.global_state_mutex));
420 
421 	switch (iscsit_global.global_svc_state) {
422 	case ISE_DISABLED:
423 	case ISE_DETACHED:
424 		return (B_FALSE);
425 	default:
426 		return (B_TRUE);
427 	}
428 	/* NOTREACHED */
429 }
430 
431 /* ARGSUSED */
432 static int
433 iscsit_drv_ioctl(dev_t drv, int cmd, intptr_t argp, int flag, cred_t *cred,
434     int *retval)
435 {
436 	iscsit_ioc_set_config_t		setcfg;
437 	iscsit_ioc_set_config32_t	setcfg32;
438 	char				*cfg_pnvlist = NULL;
439 	nvlist_t			*cfg_nvlist = NULL;
440 	it_config_t			*cfg = NULL;
441 	idm_status_t			idmrc;
442 	int				rc = 0;
443 
444 	if (drv_priv(cred) != 0) {
445 		return (EPERM);
446 	}
447 
448 	mutex_enter(&iscsit_global.global_state_mutex);
449 
450 	/*
451 	 * Validate ioctl requests against global service state
452 	 */
453 	switch (iscsit_global.global_svc_state) {
454 	case ISE_ENABLED:
455 		if (cmd == ISCSIT_IOC_DISABLE_SVC) {
456 			iscsit_global.global_svc_state = ISE_DISABLING;
457 		} else if (cmd == ISCSIT_IOC_ENABLE_SVC) {
458 			/* Already enabled */
459 			mutex_exit(&iscsit_global.global_state_mutex);
460 			return (0);
461 		} else {
462 			iscsit_global.global_svc_state = ISE_BUSY;
463 		}
464 		break;
465 	case ISE_DISABLED:
466 		if (cmd == ISCSIT_IOC_ENABLE_SVC) {
467 			iscsit_global.global_svc_state = ISE_ENABLING;
468 		} else if (cmd == ISCSIT_IOC_DISABLE_SVC) {
469 			/* Already disabled */
470 			mutex_exit(&iscsit_global.global_state_mutex);
471 			return (0);
472 		} else {
473 			rc = EFAULT;
474 		}
475 		break;
476 	case ISE_BUSY:
477 	case ISE_ENABLING:
478 	case ISE_DISABLING:
479 		rc = EAGAIN;
480 		break;
481 	case ISE_DETACHED:
482 	default:
483 		rc = EFAULT;
484 		break;
485 	}
486 
487 	mutex_exit(&iscsit_global.global_state_mutex);
488 	if (rc != 0)
489 		return (rc);
490 
491 	/* Handle ioctl request (enable/disable have already been handled) */
492 	switch (cmd) {
493 	case ISCSIT_IOC_SET_CONFIG:
494 		/* Any errors must set state back to ISE_ENABLED */
495 		switch (ddi_model_convert_from(flag & FMODELS)) {
496 		case DDI_MODEL_ILP32:
497 			if (ddi_copyin((void *)argp, &setcfg32,
498 			    sizeof (iscsit_ioc_set_config32_t), flag) != 0) {
499 				rc = EFAULT;
500 				goto cleanup;
501 			}
502 
503 			setcfg.set_cfg_pnvlist =
504 			    (char *)((uintptr_t)setcfg32.set_cfg_pnvlist);
505 			setcfg.set_cfg_vers = setcfg32.set_cfg_vers;
506 			setcfg.set_cfg_pnvlist_len =
507 			    setcfg32.set_cfg_pnvlist_len;
508 			break;
509 		case DDI_MODEL_NONE:
510 			if (ddi_copyin((void *)argp, &setcfg,
511 			    sizeof (iscsit_ioc_set_config_t), flag) != 0) {
512 				rc = EFAULT;
513 				goto cleanup;
514 			}
515 			break;
516 		default:
517 			rc = EFAULT;
518 			goto cleanup;
519 		}
520 
521 		/* Check API version */
522 		if (setcfg.set_cfg_vers != ISCSIT_API_VERS0) {
523 			rc = EINVAL;
524 			goto cleanup;
525 		}
526 
527 		/* Config is in packed nvlist format so unpack it */
528 		cfg_pnvlist = kmem_alloc(setcfg.set_cfg_pnvlist_len,
529 		    KM_SLEEP);
530 		ASSERT(cfg_pnvlist != NULL);
531 
532 		if (ddi_copyin(setcfg.set_cfg_pnvlist, cfg_pnvlist,
533 		    setcfg.set_cfg_pnvlist_len, flag) != 0) {
534 			rc = EFAULT;
535 			goto cleanup;
536 		}
537 
538 		rc = nvlist_unpack(cfg_pnvlist, setcfg.set_cfg_pnvlist_len,
539 		    &cfg_nvlist, KM_SLEEP);
540 		if (rc != 0) {
541 			goto cleanup;
542 		}
543 
544 		/* Translate nvlist */
545 		rc = it_nv_to_config(cfg_nvlist, &cfg);
546 		if (rc != 0) {
547 			cmn_err(CE_WARN, "Configuration is invalid");
548 			goto cleanup;
549 		}
550 
551 		/* Update config */
552 		rc = iscsit_config_merge(cfg);
553 		/* FALLTHROUGH */
554 
555 cleanup:
556 		if (cfg)
557 			it_config_free_cmn(cfg);
558 		if (cfg_pnvlist)
559 			kmem_free(cfg_pnvlist, setcfg.set_cfg_pnvlist_len);
560 		if (cfg_nvlist)
561 			nvlist_free(cfg_nvlist);
562 
563 		/*
564 		 * Now that the reconfig is complete set our state back to
565 		 * enabled.
566 		 */
567 		mutex_enter(&iscsit_global.global_state_mutex);
568 		iscsit_global.global_svc_state = ISE_ENABLED;
569 		mutex_exit(&iscsit_global.global_state_mutex);
570 		break;
571 	case ISCSIT_IOC_ENABLE_SVC: {
572 		iscsit_hostinfo_t hostinfo;
573 
574 		if (ddi_copyin((void *)argp, &hostinfo.length,
575 		    sizeof (hostinfo.length), flag) != 0) {
576 			mutex_enter(&iscsit_global.global_state_mutex);
577 			iscsit_global.global_svc_state = ISE_DISABLED;
578 			mutex_exit(&iscsit_global.global_state_mutex);
579 			return (EFAULT);
580 		}
581 
582 		if (hostinfo.length > sizeof (hostinfo.fqhn))
583 			hostinfo.length = sizeof (hostinfo.fqhn);
584 
585 		if (ddi_copyin((void *)((caddr_t)argp +
586 		    sizeof (hostinfo.length)), &hostinfo.fqhn,
587 		    hostinfo.length, flag) != 0) {
588 			mutex_enter(&iscsit_global.global_state_mutex);
589 			iscsit_global.global_svc_state = ISE_DISABLED;
590 			mutex_exit(&iscsit_global.global_state_mutex);
591 			return (EFAULT);
592 		}
593 
594 		idmrc = iscsit_enable_svc(&hostinfo);
595 		mutex_enter(&iscsit_global.global_state_mutex);
596 		if (idmrc == IDM_STATUS_SUCCESS) {
597 			iscsit_global.global_svc_state = ISE_ENABLED;
598 		} else {
599 			rc = EIO;
600 			iscsit_global.global_svc_state = ISE_DISABLED;
601 		}
602 		mutex_exit(&iscsit_global.global_state_mutex);
603 		break;
604 	}
605 	case ISCSIT_IOC_DISABLE_SVC:
606 		iscsit_disable_svc();
607 		mutex_enter(&iscsit_global.global_state_mutex);
608 		iscsit_global.global_svc_state = ISE_DISABLED;
609 		mutex_exit(&iscsit_global.global_state_mutex);
610 		break;
611 
612 	default:
613 		rc = EINVAL;
614 		mutex_enter(&iscsit_global.global_state_mutex);
615 		iscsit_global.global_svc_state = ISE_ENABLED;
616 		mutex_exit(&iscsit_global.global_state_mutex);
617 	}
618 
619 	return (rc);
620 }
621 
622 static idm_status_t
623 iscsit_init(dev_info_t *dip)
624 {
625 	int			rc;
626 
627 	rc = ldi_ident_from_dip(dip, &iscsit_global.global_li);
628 	ASSERT(rc == 0);  /* Failure indicates invalid argument */
629 
630 	iscsit_global.global_svc_state = ISE_DISABLED;
631 
632 	return (IDM_STATUS_SUCCESS);
633 }
634 
635 /*
636  * iscsit_enable_svc
637  *
638  * registers all the configured targets and target portals with STMF
639  */
640 static idm_status_t
641 iscsit_enable_svc(iscsit_hostinfo_t *hostinfo)
642 {
643 	stmf_port_provider_t	*pp;
644 	stmf_dbuf_store_t	*dbuf_store;
645 	boolean_t		did_iscsit_isns_init;
646 	idm_status_t		retval = IDM_STATUS_SUCCESS;
647 
648 	ASSERT(iscsit_global.global_svc_state == ISE_ENABLING);
649 
650 	/*
651 	 * Make sure that can tell if we have partially allocated
652 	 * in case we need to exit and tear down anything allocated.
653 	 */
654 	iscsit_global.global_tsih_pool = NULL;
655 	iscsit_global.global_dbuf_store = NULL;
656 	iscsit_status_pdu_cache = NULL;
657 	pp = NULL;
658 	iscsit_global.global_pp = NULL;
659 	iscsit_global.global_default_tpg = NULL;
660 	did_iscsit_isns_init = B_FALSE;
661 	iscsit_global.global_dispatch_taskq = NULL;
662 
663 	/* Setup remaining fields in iscsit_global_t */
664 	idm_refcnt_init(&iscsit_global.global_refcnt,
665 	    &iscsit_global);
666 
667 	avl_create(&iscsit_global.global_discovery_sessions,
668 	    iscsit_sess_avl_compare, sizeof (iscsit_sess_t),
669 	    offsetof(iscsit_sess_t, ist_tgt_ln));
670 
671 	avl_create(&iscsit_global.global_target_list,
672 	    iscsit_tgt_avl_compare, sizeof (iscsit_tgt_t),
673 	    offsetof(iscsit_tgt_t, target_global_ln));
674 
675 	list_create(&iscsit_global.global_deleted_target_list,
676 	    sizeof (iscsit_tgt_t),
677 	    offsetof(iscsit_tgt_t, target_global_deleted_ln));
678 
679 	avl_create(&iscsit_global.global_tpg_list,
680 	    iscsit_tpg_avl_compare, sizeof (iscsit_tpg_t),
681 	    offsetof(iscsit_tpg_t, tpg_global_ln));
682 
683 	avl_create(&iscsit_global.global_ini_list,
684 	    iscsit_ini_avl_compare, sizeof (iscsit_ini_t),
685 	    offsetof(iscsit_ini_t, ini_global_ln));
686 
687 	iscsit_global.global_tsih_pool = vmem_create("iscsit_tsih_pool",
688 	    (void *)1, ISCSI_MAX_TSIH, 1, NULL, NULL, NULL, 0,
689 	    VM_SLEEP | VMC_IDENTIFIER);
690 
691 	/*
692 	 * Setup STMF dbuf store.  Our buffers are bound to a specific
693 	 * connection so we really can't let STMF cache buffers for us.
694 	 * Consequently we'll just allocate one global buffer store.
695 	 */
696 	dbuf_store = stmf_alloc(STMF_STRUCT_DBUF_STORE, 0, 0);
697 	if (dbuf_store == NULL) {
698 		retval = IDM_STATUS_FAIL;
699 		goto tear_down_and_return;
700 	}
701 	dbuf_store->ds_alloc_data_buf = iscsit_dbuf_alloc;
702 	dbuf_store->ds_free_data_buf = iscsit_dbuf_free;
703 	dbuf_store->ds_port_private = NULL;
704 	iscsit_global.global_dbuf_store = dbuf_store;
705 
706 	/* Status PDU cache */
707 	iscsit_status_pdu_cache = kmem_cache_create("iscsit_status_pdu_cache",
708 	    sizeof (idm_pdu_t) + sizeof (iscsi_scsi_rsp_hdr_t), 8,
709 	    &iscsit_status_pdu_constructor,
710 	    NULL, NULL, NULL, NULL, KM_SLEEP);
711 
712 	/* Default TPG and portal */
713 	iscsit_global.global_default_tpg = iscsit_tpg_createdefault();
714 	if (iscsit_global.global_default_tpg == NULL) {
715 		retval = IDM_STATUS_FAIL;
716 		goto tear_down_and_return;
717 	}
718 
719 	/* initialize isns client */
720 	(void) iscsit_isns_init(hostinfo);
721 	did_iscsit_isns_init = B_TRUE;
722 
723 	/* Register port provider */
724 	pp = stmf_alloc(STMF_STRUCT_PORT_PROVIDER, 0, 0);
725 	if (pp == NULL) {
726 		retval = IDM_STATUS_FAIL;
727 		goto tear_down_and_return;
728 	}
729 
730 	pp->pp_portif_rev = PORTIF_REV_1;
731 	pp->pp_instance = 0;
732 	pp->pp_name = ISCSIT_MODNAME;
733 	pp->pp_cb = iscsit_pp_cb;
734 
735 	iscsit_global.global_pp = pp;
736 
737 
738 	if (stmf_register_port_provider(pp) != STMF_SUCCESS) {
739 		retval = IDM_STATUS_FAIL;
740 		goto tear_down_and_return;
741 	}
742 
743 	iscsit_global.global_dispatch_taskq = taskq_create("iscsit_dispatch",
744 	    1, minclsyspri, 16, 16, TASKQ_PREPOPULATE);
745 
746 	/* Scan staged PDUs, meaningful in MC/S situations */
747 	iscsit_rxpdu_queue_monitor_start();
748 
749 	return (IDM_STATUS_SUCCESS);
750 
751 tear_down_and_return:
752 
753 	if (iscsit_global.global_dispatch_taskq) {
754 		taskq_destroy(iscsit_global.global_dispatch_taskq);
755 		iscsit_global.global_dispatch_taskq = NULL;
756 	}
757 
758 	if (did_iscsit_isns_init)
759 		iscsit_isns_fini();
760 
761 	if (iscsit_global.global_default_tpg) {
762 		iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);
763 		iscsit_global.global_default_tpg = NULL;
764 	}
765 
766 	if (iscsit_global.global_pp)
767 		iscsit_global.global_pp = NULL;
768 
769 	if (pp)
770 		stmf_free(pp);
771 
772 	if (iscsit_status_pdu_cache) {
773 		kmem_cache_destroy(iscsit_status_pdu_cache);
774 		iscsit_status_pdu_cache = NULL;
775 	}
776 
777 	if (iscsit_global.global_dbuf_store) {
778 		stmf_free(iscsit_global.global_dbuf_store);
779 		iscsit_global.global_dbuf_store = NULL;
780 	}
781 
782 	if (iscsit_global.global_tsih_pool) {
783 		vmem_destroy(iscsit_global.global_tsih_pool);
784 		iscsit_global.global_tsih_pool = NULL;
785 	}
786 
787 	avl_destroy(&iscsit_global.global_ini_list);
788 	avl_destroy(&iscsit_global.global_tpg_list);
789 	list_destroy(&iscsit_global.global_deleted_target_list);
790 	avl_destroy(&iscsit_global.global_target_list);
791 	avl_destroy(&iscsit_global.global_discovery_sessions);
792 
793 	idm_refcnt_destroy(&iscsit_global.global_refcnt);
794 
795 	return (retval);
796 }
797 
798 /*
799  * iscsit_disable_svc
800  *
801  * clean up all existing connections and deregister targets from STMF
802  */
803 static void
804 iscsit_disable_svc(void)
805 {
806 	iscsit_sess_t	*sess;
807 
808 	ASSERT(iscsit_global.global_svc_state == ISE_DISABLING);
809 
810 	iscsit_rxpdu_queue_monitor_stop();
811 
812 	/* tear down discovery sessions */
813 	for (sess = avl_first(&iscsit_global.global_discovery_sessions);
814 	    sess != NULL;
815 	    sess = AVL_NEXT(&iscsit_global.global_discovery_sessions, sess))
816 		iscsit_sess_close(sess);
817 
818 	/*
819 	 * Passing NULL to iscsit_config_merge tells it to go to an empty
820 	 * config.
821 	 */
822 	(void) iscsit_config_merge(NULL);
823 
824 	/*
825 	 * Wait until there are no more global references
826 	 */
827 	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
828 	idm_refcnt_destroy(&iscsit_global.global_refcnt);
829 
830 	/*
831 	 * Default TPG must be destroyed after global_refcnt is 0.
832 	 */
833 	iscsit_tpg_destroydefault(iscsit_global.global_default_tpg);
834 
835 	avl_destroy(&iscsit_global.global_discovery_sessions);
836 	list_destroy(&iscsit_global.global_deleted_target_list);
837 	avl_destroy(&iscsit_global.global_target_list);
838 	avl_destroy(&iscsit_global.global_tpg_list);
839 	avl_destroy(&iscsit_global.global_ini_list);
840 
841 	taskq_destroy(iscsit_global.global_dispatch_taskq);
842 
843 	iscsit_isns_fini();
844 
845 	stmf_free(iscsit_global.global_dbuf_store);
846 	iscsit_global.global_dbuf_store = NULL;
847 
848 	(void) stmf_deregister_port_provider(iscsit_global.global_pp);
849 	stmf_free(iscsit_global.global_pp);
850 	iscsit_global.global_pp = NULL;
851 
852 	kmem_cache_destroy(iscsit_status_pdu_cache);
853 	iscsit_status_pdu_cache = NULL;
854 
855 	vmem_destroy(iscsit_global.global_tsih_pool);
856 	iscsit_global.global_tsih_pool = NULL;
857 }
858 
859 void
860 iscsit_global_hold()
861 {
862 	/*
863 	 * To take out a global hold, we must either own the global
864 	 * state mutex or we must be running inside of an ioctl that
865 	 * has set the global state to ISE_BUSY, ISE_DISABLING, or
866 	 * ISE_ENABLING.  We don't track the "owner" for these flags,
867 	 * so just checking if they are set is enough for now.
868 	 */
869 	ASSERT((iscsit_global.global_svc_state == ISE_ENABLING) ||
870 	    (iscsit_global.global_svc_state == ISE_DISABLING) ||
871 	    (iscsit_global.global_svc_state == ISE_BUSY) ||
872 	    MUTEX_HELD(&iscsit_global.global_state_mutex));
873 
874 	idm_refcnt_hold(&iscsit_global.global_refcnt);
875 }
876 
877 void
878 iscsit_global_rele()
879 {
880 	idm_refcnt_rele(&iscsit_global.global_refcnt);
881 }
882 
883 void
884 iscsit_global_wait_ref()
885 {
886 	idm_refcnt_wait_ref(&iscsit_global.global_refcnt);
887 }
888 
889 /*
890  * IDM callbacks
891  */
892 
893 /*ARGSUSED*/
894 void
895 iscsit_rx_pdu(idm_conn_t *ic, idm_pdu_t *rx_pdu)
896 {
897 	iscsit_conn_t *ict = ic->ic_handle;
898 	switch (IDM_PDU_OPCODE(rx_pdu)) {
899 	case ISCSI_OP_SCSI_CMD:
900 		ASSERT(0); /* Shouldn't happen */
901 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
902 		break;
903 	case ISCSI_OP_SNACK_CMD:
904 		/*
905 		 * We'll need to handle this when we support ERL1/2.  For
906 		 * now we treat it as a protocol error.
907 		 */
908 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
909 		idm_conn_event(ic, CE_TRANSPORT_FAIL, NULL);
910 		break;
911 	case ISCSI_OP_SCSI_TASK_MGT_MSG:
912 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
913 			iscsit_set_cmdsn(ict, rx_pdu);
914 			iscsit_op_scsi_task_mgmt(ict, rx_pdu);
915 		}
916 		break;
917 	case ISCSI_OP_NOOP_OUT:
918 	case ISCSI_OP_LOGIN_CMD:
919 	case ISCSI_OP_TEXT_CMD:
920 	case ISCSI_OP_LOGOUT_CMD:
921 		/*
922 		 * If/when we switch to userland processing these PDU's
923 		 * will be handled by iscsitd.
924 		 */
925 		iscsit_deferred_dispatch(rx_pdu);
926 		break;
927 	default:
928 		/* Protocol error */
929 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
930 		idm_conn_event(ic, CE_TRANSPORT_FAIL, NULL);
931 		break;
932 	}
933 }
934 
935 /*ARGSUSED*/
936 void
937 iscsit_rx_pdu_error(idm_conn_t *ic, idm_pdu_t *rx_pdu, idm_status_t status)
938 {
939 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
940 }
941 
942 void
943 iscsit_task_aborted(idm_task_t *idt, idm_status_t status)
944 {
945 	iscsit_task_t *itask = idt->idt_private;
946 
947 	switch (status) {
948 	case IDM_STATUS_SUSPENDED:
949 		break;
950 	case IDM_STATUS_ABORTED:
951 		mutex_enter(&itask->it_mutex);
952 		itask->it_aborted = B_TRUE;
953 		/*
954 		 * We rely on the fact that STMF tracks outstanding
955 		 * buffer transfers and will free all of our buffers
956 		 * before freeing the task so we don't need to
957 		 * explicitly free the buffers from iscsit/idm
958 		 */
959 		if (itask->it_stmf_abort) {
960 			mutex_exit(&itask->it_mutex);
961 			/*
962 			 * Task is no longer active
963 			 */
964 			iscsit_task_done(itask);
965 
966 			/*
967 			 * STMF has already asked for this task to be aborted
968 			 *
969 			 * STMF specification is wrong... says to return
970 			 * STMF_ABORTED, the code actually looks for
971 			 * STMF_ABORT_SUCCESS.
972 			 */
973 			stmf_task_lport_aborted(itask->it_stmf_task,
974 			    STMF_ABORT_SUCCESS, STMF_IOF_LPORT_DONE);
975 			return;
976 		} else {
977 			mutex_exit(&itask->it_mutex);
978 			/*
979 			 * Tell STMF to stop processing the task.
980 			 */
981 			stmf_abort(STMF_QUEUE_TASK_ABORT, itask->it_stmf_task,
982 			    STMF_ABORTED, NULL);
983 			return;
984 		}
985 		/*NOTREACHED*/
986 	default:
987 		ASSERT(0);
988 	}
989 }
990 
991 /*ARGSUSED*/
992 idm_status_t
993 iscsit_client_notify(idm_conn_t *ic, idm_client_notify_t icn,
994     uintptr_t data)
995 {
996 	idm_status_t rc = IDM_STATUS_SUCCESS;
997 
998 	/*
999 	 * IDM client notifications will never occur at interrupt level
1000 	 * since they are generated from the connection state machine which
1001 	 * running on taskq threads.
1002 	 *
1003 	 */
1004 	switch (icn) {
1005 	case CN_CONNECT_ACCEPT:
1006 		rc = iscsit_conn_accept(ic); /* No data */
1007 		break;
1008 	case CN_FFP_ENABLED:
1009 		rc = iscsit_ffp_enabled(ic); /* No data */
1010 		break;
1011 	case CN_FFP_DISABLED:
1012 		/*
1013 		 * Data indicates whether this was the result of an
1014 		 * explicit logout request.
1015 		 */
1016 		rc = iscsit_ffp_disabled(ic, (idm_ffp_disable_t)data);
1017 		break;
1018 	case CN_CONNECT_LOST:
1019 		rc = iscsit_conn_lost(ic);
1020 		break;
1021 	case CN_CONNECT_DESTROY:
1022 		rc = iscsit_conn_destroy(ic);
1023 		break;
1024 	case CN_LOGIN_FAIL:
1025 		/*
1026 		 * Force the login state machine to completion
1027 		 */
1028 		rc = iscsit_login_fail(ic);
1029 		break;
1030 	default:
1031 		rc = IDM_STATUS_REJECT;
1032 		break;
1033 	}
1034 
1035 	return (rc);
1036 }
1037 
1038 /*
1039  * iscsit_update_statsn is invoked for all the PDUs which have the StatSN
1040  * field in the header. The StatSN is incremented if the IDM_PDU_ADVANCE_STATSN
1041  * flag is set in the pdu flags field. The StatSN is connection-wide and is
1042  * protected by the mutex ict_statsn_mutex. For Data-In PDUs, if the flag
1043  * IDM_TASK_PHASECOLLAPSE_REQ is set, the status (phase-collapse) is also filled
1044  */
1045 void
1046 iscsit_update_statsn(idm_task_t *idm_task, idm_pdu_t *pdu)
1047 {
1048 	iscsi_scsi_rsp_hdr_t *rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1049 	iscsit_conn_t *ict = (iscsit_conn_t *)pdu->isp_ic->ic_handle;
1050 	iscsit_task_t *itask = NULL;
1051 	scsi_task_t *task = NULL;
1052 
1053 	mutex_enter(&ict->ict_statsn_mutex);
1054 	rsp->statsn = htonl(ict->ict_statsn);
1055 	if (pdu->isp_flags & IDM_PDU_ADVANCE_STATSN)
1056 		ict->ict_statsn++;
1057 	mutex_exit(&ict->ict_statsn_mutex);
1058 
1059 	/*
1060 	 * The last SCSI Data PDU passed for a command may also contain the
1061 	 * status if the status indicates termination with no expections, i.e.
1062 	 * no sense data or response involved. If the command completes with
1063 	 * an error, then the response and sense data will be sent in a
1064 	 * separate iSCSI Response PDU.
1065 	 */
1066 	if ((idm_task) && (idm_task->idt_flags & IDM_TASK_PHASECOLLAPSE_REQ)) {
1067 		itask = idm_task->idt_private;
1068 		task = itask->it_stmf_task;
1069 
1070 		rsp->cmd_status = task->task_scsi_status;
1071 		rsp->flags	|= ISCSI_FLAG_DATA_STATUS;
1072 		if (task->task_status_ctrl & TASK_SCTRL_OVER) {
1073 			rsp->flags |= ISCSI_FLAG_CMD_OVERFLOW;
1074 		} else if (task->task_status_ctrl & TASK_SCTRL_UNDER) {
1075 			rsp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
1076 		}
1077 		rsp->residual_count = htonl(task->task_resid);
1078 
1079 		/*
1080 		 * Removing the task from the session task list
1081 		 * just before the status is sent in the last
1082 		 * Data PDU transfer
1083 		 */
1084 		iscsit_task_done(itask);
1085 	}
1086 }
1087 
1088 void
1089 iscsit_build_hdr(idm_task_t *idm_task, idm_pdu_t *pdu, uint8_t opcode)
1090 {
1091 	iscsit_task_t *itask = idm_task->idt_private;
1092 	iscsi_data_rsp_hdr_t *dh = (iscsi_data_rsp_hdr_t *)pdu->isp_hdr;
1093 
1094 	/*
1095 	 * We acquired iscsit_sess_t.ist_sn_mutex in iscsit_xfer_scsi_data
1096 	 */
1097 	ASSERT(MUTEX_HELD(&itask->it_ict->ict_sess->ist_sn_mutex));
1098 	/*
1099 	 * Lun is only required if the opcode == ISCSI_OP_SCSI_DATA_RSP
1100 	 * and the 'A' bit is to be set
1101 	 */
1102 	dh->opcode = opcode;
1103 	dh->itt = itask->it_itt;
1104 	dh->ttt = itask->it_ttt;
1105 
1106 	dh->expcmdsn = htonl(itask->it_ict->ict_sess->ist_expcmdsn);
1107 	dh->maxcmdsn = htonl(itask->it_ict->ict_sess->ist_maxcmdsn);
1108 
1109 	/*
1110 	 * IDM must set:
1111 	 *
1112 	 * data.flags and rtt.flags
1113 	 * data.dlength
1114 	 * data.datasn
1115 	 * data.offset
1116 	 * statsn, residual_count and cmd_status (for phase collapse)
1117 	 * rtt.rttsn
1118 	 * rtt.data_offset
1119 	 * rtt.data_length
1120 	 */
1121 }
1122 
1123 void
1124 iscsit_keepalive(idm_conn_t *ic)
1125 {
1126 	idm_pdu_t		*nop_in_pdu;
1127 	iscsi_nop_in_hdr_t	*nop_in;
1128 	iscsit_conn_t		*ict = ic->ic_handle;
1129 
1130 	/*
1131 	 * IDM noticed the connection has been idle for too long so it's
1132 	 * time to provoke some activity.  Build and transmit an iSCSI
1133 	 * nop-in PDU -- when the initiator responds it will be counted
1134 	 * as "activity" and keep the connection alive.
1135 	 *
1136 	 * We don't actually care about the response here at the iscsit level
1137 	 * so we will just throw it away without looking at it when it arrives.
1138 	 */
1139 	nop_in_pdu = idm_pdu_alloc(sizeof (*nop_in), 0);
1140 	idm_pdu_init(nop_in_pdu, ic, NULL, NULL);
1141 	nop_in = (iscsi_nop_in_hdr_t *)nop_in_pdu->isp_hdr;
1142 	bzero(nop_in, sizeof (*nop_in));
1143 	nop_in->opcode = ISCSI_OP_NOOP_IN;
1144 	nop_in->flags = ISCSI_FLAG_FINAL;
1145 	nop_in->itt = ISCSI_RSVD_TASK_TAG;
1146 	/*
1147 	 * When the target sends a NOP-In as a Ping, the target transfer tag
1148 	 * is set to a valid (not reserved) value and the initiator task tag
1149 	 * is set to ISCSI_RSVD_TASK_TAG (0xffffffff). In this case the StatSN
1150 	 * will always contain the next sequence number but the StatSN for the
1151 	 * connection is not advanced after this PDU is sent.
1152 	 */
1153 	nop_in_pdu->isp_flags |= IDM_PDU_SET_STATSN;
1154 	/*
1155 	 * This works because we don't currently allocate ttt's anywhere else
1156 	 * in iscsit so as long as we stay out of IDM's range we are safe.
1157 	 * If we need to allocate ttt's for other PDU's in the future this will
1158 	 * need to be improved.
1159 	 */
1160 	mutex_enter(&ict->ict_mutex);
1161 	nop_in->ttt = ict->ict_keepalive_ttt;
1162 	ict->ict_keepalive_ttt++;
1163 	if (ict->ict_keepalive_ttt == ISCSI_RSVD_TASK_TAG)
1164 		ict->ict_keepalive_ttt = IDM_TASKIDS_MAX;
1165 	mutex_exit(&ict->ict_mutex);
1166 
1167 	iscsit_pdu_tx(nop_in_pdu);
1168 }
1169 
1170 static idm_status_t
1171 iscsit_conn_accept(idm_conn_t *ic)
1172 {
1173 	iscsit_conn_t *ict;
1174 
1175 	/*
1176 	 * We need to get a global hold here to ensure that the service
1177 	 * doesn't get shutdown prior to establishing a session. This
1178 	 * gets released in iscsit_conn_destroy().
1179 	 */
1180 	mutex_enter(&iscsit_global.global_state_mutex);
1181 	if (iscsit_global.global_svc_state != ISE_ENABLED) {
1182 		mutex_exit(&iscsit_global.global_state_mutex);
1183 		return (IDM_STATUS_FAIL);
1184 	}
1185 	iscsit_global_hold();
1186 	mutex_exit(&iscsit_global.global_state_mutex);
1187 
1188 	/*
1189 	 * Allocate an associated iscsit structure to represent this
1190 	 * connection.  We shouldn't really create a session until we
1191 	 * get the first login PDU.
1192 	 */
1193 	ict = kmem_zalloc(sizeof (*ict), KM_SLEEP);
1194 
1195 	ict->ict_ic = ic;
1196 	ict->ict_statsn = 1;
1197 	ict->ict_keepalive_ttt = IDM_TASKIDS_MAX; /* Avoid IDM TT range */
1198 	ic->ic_handle = ict;
1199 	mutex_init(&ict->ict_mutex, NULL, MUTEX_DRIVER, NULL);
1200 	mutex_init(&ict->ict_statsn_mutex, NULL, MUTEX_DRIVER, NULL);
1201 	idm_refcnt_init(&ict->ict_refcnt, ict);
1202 
1203 	/*
1204 	 * Initialize login state machine
1205 	 */
1206 	if (iscsit_login_sm_init(ict) != IDM_STATUS_SUCCESS) {
1207 		iscsit_global_rele();
1208 		/*
1209 		 * Cleanup the ict after idm notifies us about this failure
1210 		 */
1211 		return (IDM_STATUS_FAIL);
1212 	}
1213 
1214 	return (IDM_STATUS_SUCCESS);
1215 }
1216 
1217 idm_status_t
1218 iscsit_conn_reinstate(iscsit_conn_t *reinstate_ict, iscsit_conn_t *new_ict)
1219 {
1220 	idm_status_t	result;
1221 
1222 	/*
1223 	 * Note in new connection state that this connection is
1224 	 * reinstating an existing connection.
1225 	 */
1226 	new_ict->ict_reinstating = B_TRUE;
1227 	new_ict->ict_reinstate_conn = reinstate_ict;
1228 	new_ict->ict_statsn = reinstate_ict->ict_statsn;
1229 
1230 	/*
1231 	 * Now generate connection state machine event to existing connection
1232 	 * so that it starts the cleanup process.
1233 	 */
1234 	result = idm_conn_reinstate_event(reinstate_ict->ict_ic,
1235 	    new_ict->ict_ic);
1236 
1237 	return (result);
1238 }
1239 
1240 void
1241 iscsit_conn_hold(iscsit_conn_t *ict)
1242 {
1243 	idm_refcnt_hold(&ict->ict_refcnt);
1244 }
1245 
1246 void
1247 iscsit_conn_rele(iscsit_conn_t *ict)
1248 {
1249 	idm_refcnt_rele(&ict->ict_refcnt);
1250 }
1251 
1252 void
1253 iscsit_conn_dispatch_hold(iscsit_conn_t *ict)
1254 {
1255 	idm_refcnt_hold(&ict->ict_dispatch_refcnt);
1256 }
1257 
1258 void
1259 iscsit_conn_dispatch_rele(iscsit_conn_t *ict)
1260 {
1261 	idm_refcnt_rele(&ict->ict_dispatch_refcnt);
1262 }
1263 
1264 static idm_status_t
1265 iscsit_login_fail(idm_conn_t *ic)
1266 {
1267 	iscsit_conn_t *ict = ic->ic_handle;
1268 
1269 	/* Generate login state machine event */
1270 	iscsit_login_sm_event(ict, ILE_LOGIN_CONN_ERROR, NULL);
1271 
1272 	return (IDM_STATUS_SUCCESS);
1273 }
1274 
1275 static idm_status_t
1276 iscsit_ffp_enabled(idm_conn_t *ic)
1277 {
1278 	iscsit_conn_t *ict = ic->ic_handle;
1279 
1280 	/* Generate session state machine event */
1281 	iscsit_sess_sm_event(ict->ict_sess, SE_CONN_LOGGED_IN, ict);
1282 
1283 	return (IDM_STATUS_SUCCESS);
1284 }
1285 
1286 static idm_status_t
1287 iscsit_ffp_disabled(idm_conn_t *ic, idm_ffp_disable_t disable_class)
1288 {
1289 	iscsit_conn_t *ict = ic->ic_handle;
1290 
1291 	/* Generate session state machine event */
1292 	switch (disable_class) {
1293 	case FD_CONN_FAIL:
1294 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FFP_FAIL, ict);
1295 		break;
1296 	case FD_CONN_LOGOUT:
1297 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FFP_DISABLE, ict);
1298 		break;
1299 	case FD_SESS_LOGOUT:
1300 		iscsit_sess_sm_event(ict->ict_sess, SE_SESSION_CLOSE, ict);
1301 		break;
1302 	default:
1303 		ASSERT(0);
1304 	}
1305 
1306 	return (IDM_STATUS_SUCCESS);
1307 }
1308 
1309 static idm_status_t
1310 iscsit_conn_lost(idm_conn_t *ic)
1311 {
1312 	iscsit_conn_t	*ict	= ic->ic_handle;
1313 	iscsit_sess_t	*ist	= ict->ict_sess;
1314 	iscsit_cbuf_t	*cbuf;
1315 	idm_pdu_t	*rx_pdu;
1316 	int i;
1317 
1318 	mutex_enter(&ict->ict_mutex);
1319 	ict->ict_lost = B_TRUE;
1320 	mutex_exit(&ict->ict_mutex);
1321 	/*
1322 	 * scrub the staging queue for all PDUs on this connection
1323 	 */
1324 	if (ist != NULL) {
1325 		mutex_enter(&ist->ist_sn_mutex);
1326 		for (cbuf = ist->ist_rxpdu_queue, i = 0;
1327 		    ((cbuf->cb_num_elems > 0) && (i < ISCSIT_RXPDU_QUEUE_LEN));
1328 		    i++) {
1329 			if (((rx_pdu = cbuf->cb_buffer[i]) != NULL) &&
1330 			    (rx_pdu->isp_ic == ic)) {
1331 				/* conn is lost, drop the pdu */
1332 				DTRACE_PROBE3(scrubbing__staging__queue,
1333 				    iscsit_sess_t *, ist, idm_conn_t *, ic,
1334 				    idm_pdu_t *, rx_pdu);
1335 				idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
1336 				cbuf->cb_buffer[i] = NULL;
1337 				cbuf->cb_num_elems--;
1338 				iscsit_conn_dispatch_rele(ict);
1339 			}
1340 		}
1341 		mutex_exit(&ist->ist_sn_mutex);
1342 	}
1343 	/*
1344 	 * Make sure there aren't any PDU's transitioning from the receive
1345 	 * handler to the dispatch taskq.
1346 	 */
1347 	idm_refcnt_wait_ref(&ict->ict_dispatch_refcnt);
1348 
1349 	return (IDM_STATUS_SUCCESS);
1350 }
1351 
1352 static idm_status_t
1353 iscsit_conn_destroy(idm_conn_t *ic)
1354 {
1355 	iscsit_conn_t *ict = ic->ic_handle;
1356 
1357 	mutex_enter(&ict->ict_mutex);
1358 	ict->ict_destroyed = B_TRUE;
1359 	mutex_exit(&ict->ict_mutex);
1360 
1361 	/* Generate session state machine event */
1362 	if (ict->ict_sess != NULL) {
1363 		/*
1364 		 * Session state machine will call iscsit_conn_destroy_done()
1365 		 * when it has removed references to this connection.
1366 		 */
1367 		iscsit_sess_sm_event(ict->ict_sess, SE_CONN_FAIL, ict);
1368 	}
1369 
1370 	ict->ict_ic = NULL;
1371 
1372 	idm_refcnt_wait_ref(&ict->ict_refcnt);
1373 
1374 	/* Reap the login state machine */
1375 	iscsit_login_sm_fini(ict);
1376 
1377 	/* Clean up any text command remnants */
1378 	iscsit_text_cmd_fini(ict);
1379 
1380 	mutex_destroy(&ict->ict_mutex);
1381 	idm_refcnt_destroy(&ict->ict_refcnt);
1382 	kmem_free(ict, sizeof (*ict));
1383 
1384 	iscsit_global_rele();
1385 
1386 	return (IDM_STATUS_SUCCESS);
1387 }
1388 
1389 /*
1390  * STMF-related functions
1391  *
1392  * iSCSI to STMF mapping
1393  *
1394  * Session == ?
1395  * Connection == bound to local port but not itself a local port
1396  * Target
1397  * Target portal (group?) == local port (really but we're not going to do this)
1398  *	iscsit needs to map connections to local ports (whatever we decide
1399  * 	they are)
1400  * Target == ?
1401  */
1402 
1403 /*ARGSUSED*/
1404 static stmf_data_buf_t *
1405 iscsit_dbuf_alloc(scsi_task_t *task, uint32_t size, uint32_t *pminsize,
1406     uint32_t flags)
1407 {
1408 	iscsit_task_t *itask = task->task_port_private;
1409 	idm_buf_t *idm_buffer;
1410 	iscsit_buf_t	*ibuf;
1411 	stmf_data_buf_t *result;
1412 	uint32_t	bsize;
1413 
1414 	/*
1415 	 * If the requested size is larger than MaxBurstLength and the
1416 	 * given pminsize is also larger than MaxBurstLength, then the
1417 	 * allocation fails (dbuf = NULL) and pminsize is modified to
1418 	 * be equal to MaxBurstLength. stmf/sbd then should re-invoke
1419 	 * this function with the corrected values for transfer.
1420 	 */
1421 	ASSERT(pminsize);
1422 	if (size <= itask->it_ict->ict_op.op_max_burst_length) {
1423 		bsize = size;
1424 	} else if (*pminsize <= itask->it_ict->ict_op.op_max_burst_length) {
1425 		bsize = itask->it_ict->ict_op.op_max_burst_length;
1426 	} else {
1427 		*pminsize = itask->it_ict->ict_op.op_max_burst_length;
1428 		return (NULL);
1429 	}
1430 
1431 	/* Alloc buffer */
1432 	idm_buffer = idm_buf_alloc(itask->it_ict->ict_ic, NULL, bsize);
1433 	if (idm_buffer != NULL) {
1434 		result = stmf_alloc(STMF_STRUCT_DATA_BUF,
1435 		    sizeof (iscsit_buf_t), 0);
1436 		if (result != NULL) {
1437 			/* Fill in stmf_data_buf_t */
1438 			ibuf = result->db_port_private;
1439 			ibuf->ibuf_idm_buf = idm_buffer;
1440 			ibuf->ibuf_stmf_buf = result;
1441 			ibuf->ibuf_is_immed = B_FALSE;
1442 			result->db_flags = DB_DONT_CACHE;
1443 			result->db_buf_size = bsize;
1444 			result->db_data_size = bsize;
1445 			result->db_sglist_length = 1;
1446 			result->db_sglist[0].seg_addr = idm_buffer->idb_buf;
1447 			result->db_sglist[0].seg_length =
1448 			    idm_buffer->idb_buflen;
1449 			return (result);
1450 		}
1451 
1452 		/* Couldn't get the stmf_data_buf_t so free the buffer */
1453 		idm_buf_free(idm_buffer);
1454 	}
1455 
1456 	return (NULL);
1457 }
1458 
1459 /*ARGSUSED*/
1460 static void
1461 iscsit_dbuf_free(stmf_dbuf_store_t *ds, stmf_data_buf_t *dbuf)
1462 {
1463 	iscsit_buf_t *ibuf = dbuf->db_port_private;
1464 
1465 	if (ibuf->ibuf_is_immed) {
1466 		/*
1467 		 * The iscsit_buf_t structure itself will be freed with its
1468 		 * associated task.  Here we just need to free the PDU that
1469 		 * held the immediate data.
1470 		 */
1471 		idm_pdu_complete(ibuf->ibuf_immed_data_pdu, IDM_STATUS_SUCCESS);
1472 		ibuf->ibuf_immed_data_pdu = 0;
1473 	} else {
1474 		idm_buf_free(ibuf->ibuf_idm_buf);
1475 		stmf_free(dbuf);
1476 	}
1477 }
1478 
1479 /*ARGSUSED*/
1480 stmf_status_t
1481 iscsit_xfer_scsi_data(scsi_task_t *task, stmf_data_buf_t *dbuf,
1482     uint32_t ioflags)
1483 {
1484 	iscsit_task_t *iscsit_task = task->task_port_private;
1485 	iscsit_sess_t *ict_sess = iscsit_task->it_ict->ict_sess;
1486 	iscsit_buf_t *ibuf = dbuf->db_port_private;
1487 	int idm_rc;
1488 
1489 	/*
1490 	 * If we are aborting then we can ignore this request
1491 	 */
1492 	if (iscsit_task->it_stmf_abort) {
1493 		return (STMF_SUCCESS);
1494 	}
1495 
1496 	/*
1497 	 * If it's not immediate data then start the transfer
1498 	 */
1499 	ASSERT(ibuf->ibuf_is_immed == B_FALSE);
1500 	if (dbuf->db_flags & DB_DIRECTION_TO_RPORT) {
1501 		/*
1502 		 * The DB_SEND_STATUS_GOOD flag in the STMF data buffer allows
1503 		 * the port provider to phase-collapse, i.e. send the status
1504 		 * along with the final data PDU for the command. The port
1505 		 * provider passes this request to the transport layer by
1506 		 * setting a flag IDM_TASK_PHASECOLLAPSE_REQ in the task.
1507 		 */
1508 		if (dbuf->db_flags & DB_SEND_STATUS_GOOD)
1509 			iscsit_task->it_idm_task->idt_flags |=
1510 			    IDM_TASK_PHASECOLLAPSE_REQ;
1511 		/*
1512 		 * IDM will call iscsit_build_hdr so lock now to serialize
1513 		 * access to the SN values.  We need to lock here to enforce
1514 		 * lock ordering
1515 		 */
1516 		mutex_enter(&ict_sess->ist_sn_mutex);
1517 		idm_rc = idm_buf_tx_to_ini(iscsit_task->it_idm_task,
1518 		    ibuf->ibuf_idm_buf, dbuf->db_relative_offset,
1519 		    dbuf->db_data_size, &iscsit_buf_xfer_cb, dbuf);
1520 		mutex_exit(&ict_sess->ist_sn_mutex);
1521 
1522 		return (iscsit_idm_to_stmf(idm_rc));
1523 	} else if (dbuf->db_flags & DB_DIRECTION_FROM_RPORT) {
1524 		/* Grab the SN lock (see comment above) */
1525 		mutex_enter(&ict_sess->ist_sn_mutex);
1526 		idm_rc = idm_buf_rx_from_ini(iscsit_task->it_idm_task,
1527 		    ibuf->ibuf_idm_buf, dbuf->db_relative_offset,
1528 		    dbuf->db_data_size, &iscsit_buf_xfer_cb, dbuf);
1529 		mutex_exit(&ict_sess->ist_sn_mutex);
1530 
1531 		return (iscsit_idm_to_stmf(idm_rc));
1532 	}
1533 
1534 	/* What are we supposed to do if there is no direction? */
1535 	return (STMF_INVALID_ARG);
1536 }
1537 
1538 static void
1539 iscsit_buf_xfer_cb(idm_buf_t *idb, idm_status_t status)
1540 {
1541 	iscsit_task_t *itask = idb->idb_task_binding->idt_private;
1542 	stmf_data_buf_t *dbuf = idb->idb_cb_arg;
1543 
1544 	dbuf->db_xfer_status = iscsit_idm_to_stmf(status);
1545 
1546 	/*
1547 	 * If the task has been aborted then we don't need to call STMF
1548 	 */
1549 	if (itask->it_stmf_abort) {
1550 		return;
1551 	}
1552 
1553 	/*
1554 	 * For ISCSI over TCP (not iSER), the last SCSI Data PDU passed
1555 	 * for a successful command contains the status as requested by
1556 	 * by COMSTAR (via the DB_SEND_STATUS_GOOD flag). But the iSER
1557 	 * transport does not support phase-collapse. So pretend we are
1558 	 * COMSTAR and send the status in a separate PDU now.
1559 	 */
1560 	if (idb->idb_task_binding->idt_flags & IDM_TASK_PHASECOLLAPSE_SUCCESS) {
1561 		/*
1562 		 * Mark task complete and notify COMSTAR
1563 		 * that the status has been sent.
1564 		 */
1565 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1566 		stmf_send_status_done(itask->it_stmf_task,
1567 		    iscsit_idm_to_stmf(status), STMF_IOF_LPORT_DONE);
1568 	} else if ((dbuf->db_flags & DB_SEND_STATUS_GOOD) &&
1569 	    status == IDM_STATUS_SUCCESS) {
1570 
1571 		/*
1572 		 * The iscsi target port provider - for iSER, emulates the
1573 		 * DB_SEND_STATUS_GOOD optimization if requested by STMF;
1574 		 * it sends the status in a separate PDU after the data
1575 		 * transfer. In this case the port provider should first
1576 		 * call stmf_data_xfer_done() to mark the transfer complete
1577 		 * and then send the status. Although STMF will free the
1578 		 * buffer at the time the task is freed, even if the transfer
1579 		 * is not marked complete, this behavior makes statistics
1580 		 * gathering and task state tracking more difficult than it
1581 		 * needs to be.
1582 		 */
1583 		stmf_data_xfer_done(itask->it_stmf_task, dbuf, 0);
1584 		if (iscsit_send_scsi_status(itask->it_stmf_task, 0)
1585 		    != STMF_SUCCESS) {
1586 			stmf_send_status_done(itask->it_stmf_task,
1587 			    STMF_FAILURE, STMF_IOF_LPORT_DONE);
1588 		}
1589 	} else {
1590 		stmf_data_xfer_done(itask->it_stmf_task, dbuf, 0);
1591 		/* don't touch dbuf after stmf_data_xfer_done */
1592 	}
1593 }
1594 
1595 
1596 /*ARGSUSED*/
1597 stmf_status_t
1598 iscsit_send_scsi_status(scsi_task_t *task, uint32_t ioflags)
1599 {
1600 	iscsit_task_t *itask = task->task_port_private;
1601 	iscsi_scsi_rsp_hdr_t *rsp;
1602 	idm_pdu_t *pdu;
1603 	int resp_datalen;
1604 
1605 	/*
1606 	 * If this task is aborted then we don't need to respond.
1607 	 */
1608 	if (itask->it_stmf_abort) {
1609 		return (STMF_SUCCESS);
1610 	}
1611 
1612 	/*
1613 	 * If this is a task management status, handle it elsewhere.
1614 	 */
1615 	if (task->task_mgmt_function != TM_NONE) {
1616 		/*
1617 		 * Don't wait for the PDU completion to tell STMF
1618 		 * the task is done -- it doesn't really matter and
1619 		 * it makes life complicated if STMF later asks us to
1620 		 * abort the request and we don't know whether the
1621 		 * status has been sent or not.
1622 		 */
1623 		itask->it_tm_responded = B_TRUE;
1624 		iscsit_send_task_mgmt_resp(itask->it_tm_pdu,
1625 		    (task->task_completion_status == STMF_SUCCESS) ?
1626 		    SCSI_TCP_TM_RESP_COMPLETE : SCSI_TCP_TM_RESP_FUNC_NOT_SUPP);
1627 		stmf_send_status_done(task, STMF_SUCCESS,
1628 		    STMF_IOF_LPORT_DONE);
1629 		return (STMF_SUCCESS);
1630 	}
1631 
1632 	/*
1633 	 * Remove the task from the session task list
1634 	 */
1635 	iscsit_task_done(itask);
1636 
1637 	/*
1638 	 * Send status
1639 	 */
1640 	mutex_enter(&itask->it_idm_task->idt_mutex);
1641 	if ((itask->it_idm_task->idt_state == TASK_ACTIVE) &&
1642 	    (task->task_completion_status == STMF_SUCCESS) &&
1643 	    (task->task_sense_length == 0) &&
1644 	    (task->task_resid == 0)) {
1645 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1646 		/* PDU callback releases task hold */
1647 		idm_task_hold(itask->it_idm_task);
1648 		mutex_exit(&itask->it_idm_task->idt_mutex);
1649 		/*
1650 		 * Fast path.  Cached status PDU's are already
1651 		 * initialized.  We just need to fill in
1652 		 * connection and task information. StatSN is
1653 		 * incremented by 1 for every status sent a
1654 		 * connection.
1655 		 */
1656 		pdu = kmem_cache_alloc(iscsit_status_pdu_cache, KM_SLEEP);
1657 		pdu->isp_ic = itask->it_ict->ict_ic;
1658 		pdu->isp_private = itask;
1659 		pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
1660 
1661 		rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1662 		rsp->itt = itask->it_itt;
1663 		/*
1664 		 * ExpDataSN is the number of R2T and Data-In (read)
1665 		 * PDUs the target has sent for the SCSI command.
1666 		 *
1667 		 * Since there is no support for bidirectional transfer
1668 		 * yet, either idt_exp_datasn or idt_exp_rttsn, but not
1669 		 * both is valid at any time
1670 		 */
1671 		rsp->expdatasn = (itask->it_idm_task->idt_exp_datasn != 0) ?
1672 		    htonl(itask->it_idm_task->idt_exp_datasn):
1673 		    htonl(itask->it_idm_task->idt_exp_rttsn);
1674 		rsp->cmd_status = task->task_scsi_status;
1675 		iscsit_pdu_tx(pdu);
1676 		return (STMF_SUCCESS);
1677 	} else {
1678 		if (itask->it_idm_task->idt_state != TASK_ACTIVE) {
1679 			mutex_exit(&itask->it_idm_task->idt_mutex);
1680 			return (STMF_FAILURE);
1681 		}
1682 		itask->it_idm_task->idt_state = TASK_COMPLETE;
1683 		/* PDU callback releases task hold */
1684 		idm_task_hold(itask->it_idm_task);
1685 		mutex_exit(&itask->it_idm_task->idt_mutex);
1686 
1687 		resp_datalen = (task->task_sense_length == 0) ? 0 :
1688 		    (task->task_sense_length + sizeof (uint16_t));
1689 
1690 		pdu = idm_pdu_alloc(sizeof (iscsi_hdr_t), resp_datalen);
1691 		idm_pdu_init(pdu, itask->it_ict->ict_ic, itask,
1692 		    iscsit_send_status_done);
1693 		pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
1694 
1695 		rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
1696 		bzero(rsp, sizeof (*rsp));
1697 		rsp->opcode = ISCSI_OP_SCSI_RSP;
1698 
1699 		rsp->flags = ISCSI_FLAG_FINAL;
1700 		if (task->task_status_ctrl & TASK_SCTRL_OVER) {
1701 			rsp->flags |= ISCSI_FLAG_CMD_OVERFLOW;
1702 		} else if (task->task_status_ctrl & TASK_SCTRL_UNDER) {
1703 			rsp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
1704 		}
1705 
1706 		rsp->bi_residual_count = 0;
1707 		rsp->residual_count = htonl(task->task_resid);
1708 		rsp->itt = itask->it_itt;
1709 		rsp->response = ISCSI_STATUS_CMD_COMPLETED;
1710 		rsp->expdatasn = (itask->it_idm_task->idt_exp_datasn != 0) ?
1711 		    htonl(itask->it_idm_task->idt_exp_datasn):
1712 		    htonl(itask->it_idm_task->idt_exp_rttsn);
1713 		rsp->cmd_status = task->task_scsi_status;
1714 		if (task->task_sense_length != 0) {
1715 			/*
1716 			 * Add a byte to provide the sense length in
1717 			 * the response
1718 			 */
1719 			*(uint16_t *)((void *)pdu->isp_data) =
1720 			    htons(task->task_sense_length);
1721 			bcopy(task->task_sense_data,
1722 			    (uint8_t *)pdu->isp_data +
1723 			    sizeof (uint16_t),
1724 			    task->task_sense_length);
1725 			hton24(rsp->dlength, resp_datalen);
1726 		}
1727 
1728 		DTRACE_PROBE5(iscsi__scsi__response,
1729 		    iscsit_conn_t *, itask->it_ict,
1730 		    uint8_t, rsp->response,
1731 		    uint8_t, rsp->cmd_status,
1732 		    idm_pdu_t *, pdu,
1733 		    scsi_task_t *, task);
1734 
1735 		iscsit_pdu_tx(pdu);
1736 
1737 		return (STMF_SUCCESS);
1738 	}
1739 }
1740 
1741 /*ARGSUSED*/
1742 static void
1743 iscsit_send_good_status_done(idm_pdu_t *pdu, idm_status_t status)
1744 {
1745 	iscsit_task_t	*itask;
1746 	boolean_t	aborted;
1747 
1748 	itask = pdu->isp_private;
1749 	aborted = itask->it_stmf_abort;
1750 
1751 	/*
1752 	 * After releasing the hold the task may be freed at any time so
1753 	 * don't touch it.
1754 	 */
1755 	idm_task_rele(itask->it_idm_task);
1756 	if (!aborted) {
1757 		stmf_send_status_done(itask->it_stmf_task,
1758 		    iscsit_idm_to_stmf(pdu->isp_status), STMF_IOF_LPORT_DONE);
1759 	}
1760 	kmem_cache_free(iscsit_status_pdu_cache, pdu);
1761 }
1762 
1763 /*ARGSUSED*/
1764 static void
1765 iscsit_send_status_done(idm_pdu_t *pdu, idm_status_t status)
1766 {
1767 	iscsit_task_t	 *itask;
1768 	boolean_t	aborted;
1769 
1770 	itask = pdu->isp_private;
1771 	aborted = itask->it_stmf_abort;
1772 
1773 	/*
1774 	 * After releasing the hold the task may be freed at any time so
1775 	 * don't touch it.
1776 	 */
1777 	idm_task_rele(itask->it_idm_task);
1778 	if (!aborted) {
1779 		stmf_send_status_done(itask->it_stmf_task,
1780 		    iscsit_idm_to_stmf(pdu->isp_status), STMF_IOF_LPORT_DONE);
1781 	}
1782 	idm_pdu_free(pdu);
1783 }
1784 
1785 
1786 void
1787 iscsit_lport_task_free(scsi_task_t *task)
1788 {
1789 	iscsit_task_t *itask = task->task_port_private;
1790 
1791 	/* We only call idm_task_start for regular tasks, not task management */
1792 	if (task->task_mgmt_function == TM_NONE) {
1793 		idm_task_done(itask->it_idm_task);
1794 		iscsit_task_free(itask);
1795 		return;
1796 	} else {
1797 		iscsit_tm_task_free(itask);
1798 	}
1799 }
1800 
1801 /*ARGSUSED*/
1802 stmf_status_t
1803 iscsit_abort(stmf_local_port_t *lport, int abort_cmd, void *arg, uint32_t flags)
1804 {
1805 	scsi_task_t	*st = (scsi_task_t *)arg;
1806 	iscsit_task_t	*iscsit_task;
1807 	idm_task_t	*idt;
1808 
1809 	/*
1810 	 * If this is a task management request then there's really not much to
1811 	 * do.
1812 	 */
1813 	if (st->task_mgmt_function != TM_NONE) {
1814 		return (STMF_ABORT_SUCCESS);
1815 	}
1816 
1817 	/*
1818 	 * Regular task, start cleaning up
1819 	 */
1820 	iscsit_task = st->task_port_private;
1821 	idt = iscsit_task->it_idm_task;
1822 	mutex_enter(&iscsit_task->it_mutex);
1823 	iscsit_task->it_stmf_abort = B_TRUE;
1824 	if (iscsit_task->it_aborted) {
1825 		mutex_exit(&iscsit_task->it_mutex);
1826 		/*
1827 		 * Task is no longer active
1828 		 */
1829 		iscsit_task_done(iscsit_task);
1830 
1831 		/*
1832 		 * STMF specification is wrong... says to return
1833 		 * STMF_ABORTED, the code actually looks for
1834 		 * STMF_ABORT_SUCCESS.
1835 		 */
1836 		return (STMF_ABORT_SUCCESS);
1837 	} else {
1838 		mutex_exit(&iscsit_task->it_mutex);
1839 		/*
1840 		 * Call IDM to abort the task.  Due to a variety of
1841 		 * circumstances the task may already be in the process of
1842 		 * aborting.
1843 		 * We'll let IDM worry about rationalizing all that except
1844 		 * for one particular instance.  If the state of the task
1845 		 * is TASK_COMPLETE, we need to indicate to the framework
1846 		 * that we are in fact done.  This typically happens with
1847 		 * framework-initiated task management type requests
1848 		 * (e.g. abort task).
1849 		 */
1850 		if (idt->idt_state == TASK_COMPLETE) {
1851 			idm_refcnt_wait_ref(&idt->idt_refcnt);
1852 			return (STMF_ABORT_SUCCESS);
1853 		} else {
1854 			idm_task_abort(idt->idt_ic, idt, AT_TASK_MGMT_ABORT);
1855 			return (STMF_SUCCESS);
1856 		}
1857 	}
1858 
1859 	/*NOTREACHED*/
1860 }
1861 
1862 /*ARGSUSED*/
1863 void
1864 iscsit_ctl(stmf_local_port_t *lport, int cmd, void *arg)
1865 {
1866 	iscsit_tgt_t		*iscsit_tgt;
1867 
1868 	ASSERT((cmd == STMF_CMD_LPORT_ONLINE) ||
1869 	    (cmd == STMF_ACK_LPORT_ONLINE_COMPLETE) ||
1870 	    (cmd == STMF_CMD_LPORT_OFFLINE) ||
1871 	    (cmd == STMF_ACK_LPORT_OFFLINE_COMPLETE));
1872 
1873 	iscsit_tgt = (iscsit_tgt_t *)lport->lport_port_private;
1874 
1875 	switch (cmd) {
1876 	case STMF_CMD_LPORT_ONLINE:
1877 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_ONLINE_REQ);
1878 		break;
1879 	case STMF_CMD_LPORT_OFFLINE:
1880 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_OFFLINE_REQ);
1881 		break;
1882 	case STMF_ACK_LPORT_ONLINE_COMPLETE:
1883 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_ONLINE_COMPLETE_ACK);
1884 		break;
1885 	case STMF_ACK_LPORT_OFFLINE_COMPLETE:
1886 		iscsit_tgt_sm_event(iscsit_tgt, TE_STMF_OFFLINE_COMPLETE_ACK);
1887 		break;
1888 
1889 	default:
1890 		break;
1891 	}
1892 }
1893 
1894 static stmf_status_t
1895 iscsit_idm_to_stmf(idm_status_t idmrc)
1896 {
1897 	switch (idmrc) {
1898 	case IDM_STATUS_SUCCESS:
1899 		return (STMF_SUCCESS);
1900 	default:
1901 		return (STMF_FAILURE);
1902 	}
1903 	/*NOTREACHED*/
1904 }
1905 
1906 void
1907 iscsit_op_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu)
1908 {
1909 	iscsit_conn_t		*ict = ic->ic_handle;
1910 
1911 	if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
1912 		iscsit_post_scsi_cmd(ic, rx_pdu);
1913 	}
1914 	iscsit_process_pdu_in_queue(ict->ict_sess);
1915 }
1916 
1917 /*
1918  * ISCSI protocol
1919  */
1920 
1921 void
1922 iscsit_post_scsi_cmd(idm_conn_t *ic, idm_pdu_t *rx_pdu)
1923 {
1924 	iscsit_conn_t		*ict;
1925 	iscsit_task_t		*itask;
1926 	scsi_task_t		*task;
1927 	iscsit_buf_t		*ibuf;
1928 	iscsi_scsi_cmd_hdr_t	*iscsi_scsi =
1929 	    (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
1930 	iscsi_addl_hdr_t	*ahs_hdr;
1931 	uint16_t		addl_cdb_len = 0;
1932 
1933 	ict = ic->ic_handle;
1934 
1935 	itask = iscsit_task_alloc(ict);
1936 	if (itask == NULL) {
1937 		/* Finish processing request */
1938 		iscsit_set_cmdsn(ict, rx_pdu);
1939 
1940 		iscsit_send_direct_scsi_resp(ict, rx_pdu,
1941 		    ISCSI_STATUS_CMD_COMPLETED, STATUS_BUSY);
1942 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
1943 		return;
1944 	}
1945 
1946 	/*
1947 	 * Note CmdSN and ITT in task.  IDM will have already validated this
1948 	 * request against the connection state so we don't need to check
1949 	 * that (the connection may have changed state in the meantime but
1950 	 * we will catch that when we try to send a response)
1951 	 */
1952 	itask->it_cmdsn = ntohl(iscsi_scsi->cmdsn);
1953 	itask->it_itt = iscsi_scsi->itt;
1954 
1955 	/*
1956 	 * Check for extended CDB AHS
1957 	 */
1958 	if (iscsi_scsi->hlength > 0) {
1959 		ahs_hdr = (iscsi_addl_hdr_t *)iscsi_scsi;
1960 		addl_cdb_len = ((ahs_hdr->ahs_hlen_hi << 8) |
1961 		    ahs_hdr->ahs_hlen_lo) - 1; /* Adjust for reserved byte */
1962 		if (((addl_cdb_len + 4) / sizeof (uint32_t)) >
1963 		    iscsi_scsi->hlength) {
1964 			/* Mangled header info, drop it */
1965 			idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
1966 			return;
1967 		}
1968 	}
1969 
1970 	ict = rx_pdu->isp_ic->ic_handle; /* IDM client private */
1971 
1972 	/*
1973 	 * Add task to session list.  This function will also check to
1974 	 * ensure that the task does not already exist.
1975 	 */
1976 	if (iscsit_task_start(itask) != IDM_STATUS_SUCCESS) {
1977 		/*
1978 		 * Task exists, free all resources and reject.  Don't
1979 		 * update expcmdsn in this case because RFC 3720 says
1980 		 * "The CmdSN of the rejected command PDU (if it is a
1981 		 * non-immediate command) MUST NOT be considered received
1982 		 * by the target (i.e., a command sequence gap must be
1983 		 * assumed for the CmdSN), even though the CmdSN of the
1984 		 * rejected command PDU may be reliably ascertained.  Upon
1985 		 * receiving the Reject, the initiator MUST plug the CmdSN
1986 		 * gap in order to continue to use the session.  The gap
1987 		 * may be plugged either by transmitting a command PDU
1988 		 * with the same CmdSN, or by aborting the task (see section
1989 		 * 6.9 on how an abort may plug a CmdSN gap)." (Section 6.3)
1990 		 */
1991 		iscsit_task_free(itask);
1992 		iscsit_send_reject(ict, rx_pdu, ISCSI_REJECT_TASK_IN_PROGRESS);
1993 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
1994 		return;
1995 	}
1996 
1997 	/* Update sequence numbers */
1998 	iscsit_set_cmdsn(ict, rx_pdu);
1999 
2000 	/*
2001 	 * Allocate STMF task
2002 	 */
2003 	itask->it_stmf_task = stmf_task_alloc(
2004 	    itask->it_ict->ict_sess->ist_lport,
2005 	    itask->it_ict->ict_sess->ist_stmf_sess, iscsi_scsi->lun,
2006 	    16 + addl_cdb_len, 0);
2007 	if (itask->it_stmf_task == NULL) {
2008 		/*
2009 		 * Either stmf really couldn't get memory for a task or,
2010 		 * more likely, the LU is currently in reset.  Either way
2011 		 * we have no choice but to fail the request.
2012 		 */
2013 		iscsit_task_done(itask);
2014 		iscsit_task_free(itask);
2015 		iscsit_send_direct_scsi_resp(ict, rx_pdu,
2016 		    ISCSI_STATUS_CMD_COMPLETED, STATUS_BUSY);
2017 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2018 		return;
2019 	}
2020 
2021 	task = itask->it_stmf_task;
2022 	task->task_port_private = itask;
2023 
2024 	bcopy(iscsi_scsi->lun, task->task_lun_no, sizeof (task->task_lun_no));
2025 
2026 	/*
2027 	 * iSCSI and Comstar use the same values.  Should we rely on this
2028 	 * or translate them bit-wise?
2029 	 */
2030 
2031 	task->task_flags =
2032 	    (((iscsi_scsi->flags & ISCSI_FLAG_CMD_READ) ? TF_READ_DATA : 0) |
2033 	    ((iscsi_scsi->flags & ISCSI_FLAG_CMD_WRITE) ? TF_WRITE_DATA : 0) |
2034 	    ((rx_pdu->isp_datalen == 0) ? 0 : TF_INITIAL_BURST));
2035 
2036 	switch (iscsi_scsi->flags & ISCSI_FLAG_CMD_ATTR_MASK) {
2037 	case ISCSI_ATTR_UNTAGGED:
2038 		break;
2039 	case ISCSI_ATTR_SIMPLE:
2040 		task->task_additional_flags |= TF_ATTR_SIMPLE_QUEUE;
2041 		break;
2042 	case ISCSI_ATTR_ORDERED:
2043 		task->task_additional_flags |= TF_ATTR_ORDERED_QUEUE;
2044 		break;
2045 	case ISCSI_ATTR_HEAD_OF_QUEUE:
2046 		task->task_additional_flags |= TF_ATTR_HEAD_OF_QUEUE;
2047 		break;
2048 	case ISCSI_ATTR_ACA:
2049 		task->task_additional_flags |= TF_ATTR_ACA;
2050 		break;
2051 	default:
2052 		/* Protocol error but just take it, treat as untagged */
2053 		break;
2054 	}
2055 
2056 
2057 	task->task_additional_flags = 0;
2058 	task->task_priority = 0;
2059 	task->task_mgmt_function = TM_NONE;
2060 
2061 	/*
2062 	 * This "task_max_nbufs" doesn't map well to BIDI.  We probably need
2063 	 * parameter for each direction.  "MaxOutstandingR2T" may very well
2064 	 * be set to one which could prevent us from doing simultaneous
2065 	 * transfers in each direction.
2066 	 */
2067 	task->task_max_nbufs = (iscsi_scsi->flags & ISCSI_FLAG_CMD_WRITE) ?
2068 	    ict->ict_op.op_max_outstanding_r2t : STMF_BUFS_MAX;
2069 	task->task_cmd_seq_no = ntohl(iscsi_scsi->itt);
2070 	task->task_expected_xfer_length = ntohl(iscsi_scsi->data_length);
2071 
2072 	/* Copy CDB */
2073 	bcopy(iscsi_scsi->scb, task->task_cdb, 16);
2074 	if (addl_cdb_len > 0) {
2075 		bcopy(ahs_hdr->ahs_extscb, task->task_cdb + 16, addl_cdb_len);
2076 	}
2077 
2078 	DTRACE_ISCSI_3(scsi__command, idm_conn_t *, ic,
2079 	    iscsi_scsi_cmd_hdr_t *, (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr,
2080 	    scsi_task_t *, task);
2081 
2082 	/*
2083 	 * Copy the transport header into the task handle from the PDU
2084 	 * handle. The transport header describes this task's remote tagged
2085 	 * buffer.
2086 	 */
2087 	if (rx_pdu->isp_transport_hdrlen != 0) {
2088 		bcopy(rx_pdu->isp_transport_hdr,
2089 		    itask->it_idm_task->idt_transport_hdr,
2090 		    rx_pdu->isp_transport_hdrlen);
2091 	}
2092 
2093 	/*
2094 	 * Tell IDM about our new active task
2095 	 */
2096 	idm_task_start(itask->it_idm_task, (uintptr_t)itask->it_itt);
2097 
2098 	/*
2099 	 * If we have any immediate data then setup the immediate buffer
2100 	 * context that comes with the task
2101 	 */
2102 	if (rx_pdu->isp_datalen) {
2103 		ibuf = itask->it_immed_data;
2104 		ibuf->ibuf_immed_data_pdu = rx_pdu;
2105 		ibuf->ibuf_stmf_buf->db_data_size = rx_pdu->isp_datalen;
2106 		ibuf->ibuf_stmf_buf->db_buf_size = rx_pdu->isp_datalen;
2107 		ibuf->ibuf_stmf_buf->db_relative_offset = 0;
2108 		ibuf->ibuf_stmf_buf->db_sglist[0].seg_length =
2109 		    rx_pdu->isp_datalen;
2110 		ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr = rx_pdu->isp_data;
2111 
2112 		DTRACE_ISCSI_8(xfer__start, idm_conn_t *, ic,
2113 		    uintptr_t, ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr,
2114 		    uint32_t, ibuf->ibuf_stmf_buf->db_relative_offset,
2115 		    uint64_t, 0, uint32_t, 0, uint32_t, 0, /* no raddr */
2116 		    uint32_t, rx_pdu->isp_datalen, int, XFER_BUF_TX_TO_INI);
2117 
2118 		/*
2119 		 * For immediate data transfer, there is no callback from
2120 		 * stmf to indicate that the initial burst of data is
2121 		 * transferred successfully. In some cases, the task can
2122 		 * get freed before execution returns from stmf_post_task.
2123 		 * Although this xfer-start/done probe accurately tracks
2124 		 * the size of the transfer, it does only provide a best
2125 		 * effort on the timing of the transfer.
2126 		 */
2127 		DTRACE_ISCSI_8(xfer__done, idm_conn_t *, ic,
2128 		    uintptr_t, ibuf->ibuf_stmf_buf->db_sglist[0].seg_addr,
2129 		    uint32_t, ibuf->ibuf_stmf_buf->db_relative_offset,
2130 		    uint64_t, 0, uint32_t, 0, uint32_t, 0, /* no raddr */
2131 		    uint32_t, rx_pdu->isp_datalen, int, XFER_BUF_TX_TO_INI);
2132 		stmf_post_task(task, ibuf->ibuf_stmf_buf);
2133 	} else {
2134 
2135 		stmf_post_task(task, NULL);
2136 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2137 	}
2138 }
2139 
2140 /*ARGSUSED*/
2141 void
2142 iscsit_deferred_dispatch(idm_pdu_t *rx_pdu)
2143 {
2144 	iscsit_conn_t *ict = rx_pdu->isp_ic->ic_handle;
2145 
2146 	/*
2147 	 * If the connection has been lost then ignore new PDU's
2148 	 */
2149 	mutex_enter(&ict->ict_mutex);
2150 	if (ict->ict_lost) {
2151 		mutex_exit(&ict->ict_mutex);
2152 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2153 		return;
2154 	}
2155 
2156 	/*
2157 	 * Grab a hold on the connection to prevent it from going away
2158 	 * between now and when the taskq function is called.
2159 	 */
2160 	iscsit_conn_dispatch_hold(ict);
2161 	mutex_exit(&ict->ict_mutex);
2162 
2163 	if (taskq_dispatch(iscsit_global.global_dispatch_taskq,
2164 	    iscsit_deferred, rx_pdu, DDI_NOSLEEP) == NULL) {
2165 		/*
2166 		 * In the unlikely scenario that we couldn't get the resources
2167 		 * to dispatch the PDU then just drop it.
2168 		 */
2169 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2170 		idm_conn_event(ict->ict_ic, CE_TRANSPORT_FAIL, NULL);
2171 		iscsit_conn_dispatch_rele(ict);
2172 	}
2173 }
2174 
2175 static void
2176 iscsit_deferred(void *rx_pdu_void)
2177 {
2178 	idm_pdu_t		*rx_pdu = rx_pdu_void;
2179 	idm_conn_t		*ic = rx_pdu->isp_ic;
2180 	iscsit_conn_t		*ict = ic->ic_handle;
2181 
2182 	/*
2183 	 * NOP and Task Management Commands can be marked for immediate
2184 	 * delivery. Commands marked as 'Immediate' are to be considered
2185 	 * for execution as soon as they arrive on the target. So these
2186 	 * should not be checked for sequence order and put in a queue.
2187 	 * The CmdSN is not advanced for Immediate Commands.
2188 	 */
2189 	switch (IDM_PDU_OPCODE(rx_pdu)) {
2190 	case ISCSI_OP_NOOP_OUT:
2191 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2192 			iscsit_set_cmdsn(ict, rx_pdu);
2193 			iscsit_pdu_op_noop(ict, rx_pdu);
2194 		}
2195 		break;
2196 	case ISCSI_OP_LOGIN_CMD:
2197 		iscsit_pdu_op_login_cmd(ict, rx_pdu);
2198 		iscsit_conn_dispatch_rele(ict);
2199 		return;
2200 	case ISCSI_OP_TEXT_CMD:
2201 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2202 			iscsit_set_cmdsn(ict, rx_pdu);
2203 			iscsit_pdu_op_text_cmd(ict, rx_pdu);
2204 		}
2205 		break;
2206 	case ISCSI_OP_LOGOUT_CMD:
2207 		if (iscsit_check_cmdsn_and_queue(rx_pdu)) {
2208 			iscsit_set_cmdsn(ict, rx_pdu);
2209 			iscsit_pdu_op_logout_cmd(ict, rx_pdu);
2210 		}
2211 		break;
2212 	default:
2213 		/* Protocol error.  IDM should have caught this */
2214 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
2215 		ASSERT(0);
2216 		break;
2217 	}
2218 	/*
2219 	 * Check if there are other PDUs in the session staging queue
2220 	 * waiting to be posted to SCSI layer.
2221 	 */
2222 	iscsit_process_pdu_in_queue(ict->ict_sess);
2223 
2224 	iscsit_conn_dispatch_rele(ict);
2225 }
2226 
2227 static void
2228 iscsit_send_direct_scsi_resp(iscsit_conn_t *ict, idm_pdu_t *rx_pdu,
2229     uint8_t response, uint8_t cmd_status)
2230 {
2231 	idm_pdu_t			*rsp_pdu;
2232 	idm_conn_t			*ic;
2233 	iscsi_scsi_rsp_hdr_t		*resp;
2234 	iscsi_scsi_cmd_hdr_t		*req =
2235 	    (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
2236 
2237 	ic = ict->ict_ic;
2238 
2239 	rsp_pdu = idm_pdu_alloc(sizeof (iscsi_scsi_rsp_hdr_t), 0);
2240 	idm_pdu_init(rsp_pdu, ic, NULL, NULL);
2241 	/*
2242 	 * StatSN is incremented by 1 for every response sent on
2243 	 * a connection except for responses sent as a result of
2244 	 * a retry or SNACK
2245 	 */
2246 	rsp_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2247 
2248 	resp = (iscsi_scsi_rsp_hdr_t *)rsp_pdu->isp_hdr;
2249 
2250 	resp->opcode = ISCSI_OP_SCSI_RSP;
2251 	resp->flags = ISCSI_FLAG_FINAL;
2252 	resp->response = response;
2253 	resp->cmd_status = cmd_status;
2254 	resp->itt = req->itt;
2255 	if ((response == ISCSI_STATUS_CMD_COMPLETED) &&
2256 	    (req->data_length != 0) &&
2257 	    ((req->flags & ISCSI_FLAG_CMD_READ) ||
2258 	    (req->flags & ISCSI_FLAG_CMD_WRITE))) {
2259 		resp->flags |= ISCSI_FLAG_CMD_UNDERFLOW;
2260 		resp->residual_count = req->data_length;
2261 	}
2262 
2263 	DTRACE_PROBE4(iscsi__scsi__direct__response,
2264 	    iscsit_conn_t *, ict,
2265 	    uint8_t, resp->response,
2266 	    uint8_t, resp->cmd_status,
2267 	    idm_pdu_t *, rsp_pdu);
2268 
2269 	iscsit_pdu_tx(rsp_pdu);
2270 }
2271 
2272 void
2273 iscsit_send_task_mgmt_resp(idm_pdu_t *tm_resp_pdu, uint8_t tm_status)
2274 {
2275 	iscsi_scsi_task_mgt_rsp_hdr_t	*tm_resp;
2276 
2277 	/*
2278 	 * The target must take note of the last-sent StatSN.
2279 	 * The StatSN is to be incremented after sending a
2280 	 * task management response. Digest recovery can only
2281 	 * work if StatSN is incremented.
2282 	 */
2283 	tm_resp_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2284 	tm_resp = (iscsi_scsi_task_mgt_rsp_hdr_t *)tm_resp_pdu->isp_hdr;
2285 	tm_resp->response = tm_status;
2286 
2287 	DTRACE_PROBE3(iscsi__scsi__tm__response,
2288 	    iscsit_conn_t *, tm_resp_pdu->isp_ic->ic_handle,
2289 	    uint8_t, tm_resp->response,
2290 	    idm_pdu_t *, tm_resp_pdu);
2291 	iscsit_pdu_tx(tm_resp_pdu);
2292 }
2293 
2294 void
2295 iscsit_op_scsi_task_mgmt(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2296 {
2297 	idm_pdu_t			*tm_resp_pdu;
2298 	iscsit_task_t			*itask;
2299 	iscsit_task_t			*tm_itask;
2300 	scsi_task_t			*task;
2301 	iscsi_scsi_task_mgt_hdr_t 	*iscsi_tm =
2302 	    (iscsi_scsi_task_mgt_hdr_t *)rx_pdu->isp_hdr;
2303 	iscsi_scsi_task_mgt_rsp_hdr_t 	*iscsi_tm_rsp =
2304 	    (iscsi_scsi_task_mgt_rsp_hdr_t *)rx_pdu->isp_hdr;
2305 	uint32_t			rtt, cmdsn, refcmdsn;
2306 	uint8_t				tm_func;
2307 
2308 	/*
2309 	 * Setup response PDU (response field will get filled in later)
2310 	 */
2311 	tm_resp_pdu = idm_pdu_alloc(sizeof (iscsi_scsi_task_mgt_rsp_hdr_t), 0);
2312 	if (tm_resp_pdu == NULL) {
2313 		/* Can't respond, just drop it */
2314 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2315 		return;
2316 	}
2317 	idm_pdu_init(tm_resp_pdu, ict->ict_ic, NULL, NULL);
2318 	iscsi_tm_rsp = (iscsi_scsi_task_mgt_rsp_hdr_t *)tm_resp_pdu->isp_hdr;
2319 	bzero(iscsi_tm_rsp, sizeof (iscsi_scsi_task_mgt_rsp_hdr_t));
2320 	iscsi_tm_rsp->opcode = ISCSI_OP_SCSI_TASK_MGT_RSP;
2321 	iscsi_tm_rsp->flags = ISCSI_FLAG_FINAL;
2322 	iscsi_tm_rsp->itt = rx_pdu->isp_hdr->itt;
2323 
2324 	/*
2325 	 * Figure out what we're being asked to do.
2326 	 */
2327 	DTRACE_PROBE4(iscsi__scsi__tm__request,
2328 	    iscsit_conn_t *, ict,
2329 	    uint8_t, (iscsi_tm->function & ISCSI_FLAG_TASK_MGMT_FUNCTION_MASK),
2330 	    uint32_t, iscsi_tm->rtt,
2331 	    idm_pdu_t *, rx_pdu);
2332 	switch (iscsi_tm->function & ISCSI_FLAG_TASK_MGMT_FUNCTION_MASK) {
2333 	case ISCSI_TM_FUNC_ABORT_TASK:
2334 		/*
2335 		 * STMF doesn't currently support the "abort task" task
2336 		 * management command although it does support aborting
2337 		 * an individual task.  We'll get STMF to abort the task
2338 		 * for us but handle the details of the task management
2339 		 * command ourselves.
2340 		 *
2341 		 * Find the task associated with the referenced task tag.
2342 		 */
2343 		rtt = iscsi_tm->rtt;
2344 		itask = (iscsit_task_t *)idm_task_find_by_handle(ict->ict_ic,
2345 		    (uintptr_t)rtt);
2346 
2347 		if (itask == NULL) {
2348 			cmdsn = ntohl(iscsi_tm->cmdsn);
2349 			refcmdsn = ntohl(iscsi_tm->refcmdsn);
2350 
2351 			/*
2352 			 * Task was not found. But the SCSI command could be
2353 			 * on the rxpdu wait queue. If RefCmdSN is within
2354 			 * the CmdSN window and less than CmdSN of the TM
2355 			 * function, return "Function Complete". Otherwise,
2356 			 * return "Task Does Not Exist".
2357 			 */
2358 
2359 			if (iscsit_cmdsn_in_window(ict, refcmdsn) &&
2360 			    iscsit_sna_lt(refcmdsn, cmdsn)) {
2361 				mutex_enter(&ict->ict_sess->ist_sn_mutex);
2362 				(void) iscsit_remove_pdu_from_queue(
2363 				    ict->ict_sess, refcmdsn);
2364 				iscsit_conn_dispatch_rele(ict);
2365 				mutex_exit(&ict->ict_sess->ist_sn_mutex);
2366 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2367 				    SCSI_TCP_TM_RESP_COMPLETE);
2368 			} else {
2369 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2370 				    SCSI_TCP_TM_RESP_NO_TASK);
2371 			}
2372 		} else {
2373 
2374 			/*
2375 			 * Tell STMF to abort the task.  This will do no harm
2376 			 * if the task is already complete.
2377 			 */
2378 			stmf_abort(STMF_QUEUE_TASK_ABORT, itask->it_stmf_task,
2379 			    STMF_ABORTED, NULL);
2380 
2381 			/*
2382 			 * Make sure the task hasn't already completed
2383 			 */
2384 			mutex_enter(&itask->it_idm_task->idt_mutex);
2385 			if ((itask->it_idm_task->idt_state == TASK_COMPLETE) ||
2386 			    (itask->it_idm_task->idt_state == TASK_IDLE)) {
2387 				/*
2388 				 * Task is complete, return "Task Does Not
2389 				 * Exist"
2390 				 */
2391 				mutex_exit(&itask->it_idm_task->idt_mutex);
2392 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2393 				    SCSI_TCP_TM_RESP_NO_TASK);
2394 			} else {
2395 				/*
2396 				 * STMF is now aborting the task, return
2397 				 * "Function Complete"
2398 				 */
2399 				mutex_exit(&itask->it_idm_task->idt_mutex);
2400 				iscsit_send_task_mgmt_resp(tm_resp_pdu,
2401 				    SCSI_TCP_TM_RESP_COMPLETE);
2402 			}
2403 			idm_task_rele(itask->it_idm_task);
2404 		}
2405 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2406 		return;
2407 
2408 	case ISCSI_TM_FUNC_ABORT_TASK_SET:
2409 		tm_func = TM_ABORT_TASK_SET;
2410 		break;
2411 
2412 	case ISCSI_TM_FUNC_CLEAR_ACA:
2413 		tm_func = TM_CLEAR_ACA;
2414 		break;
2415 
2416 	case ISCSI_TM_FUNC_CLEAR_TASK_SET:
2417 		tm_func = TM_CLEAR_TASK_SET;
2418 		break;
2419 
2420 	case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
2421 		tm_func = TM_LUN_RESET;
2422 		break;
2423 
2424 	case ISCSI_TM_FUNC_TARGET_WARM_RESET:
2425 		tm_func = TM_TARGET_WARM_RESET;
2426 		break;
2427 
2428 	case ISCSI_TM_FUNC_TARGET_COLD_RESET:
2429 		tm_func = TM_TARGET_COLD_RESET;
2430 		break;
2431 
2432 	case ISCSI_TM_FUNC_TASK_REASSIGN:
2433 		/*
2434 		 * We do not currently support allegiance reassignment.  When
2435 		 * we start supporting ERL1+, we will need to.
2436 		 */
2437 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2438 		    SCSI_TCP_TM_RESP_NO_ALLG_REASSN);
2439 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2440 		return;
2441 
2442 	default:
2443 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2444 		    SCSI_TCP_TM_RESP_REJECTED);
2445 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2446 		return;
2447 	}
2448 
2449 	tm_itask = iscsit_tm_task_alloc(ict);
2450 	if (tm_itask == NULL) {
2451 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2452 		    SCSI_TCP_TM_RESP_REJECTED);
2453 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2454 		return;
2455 	}
2456 
2457 
2458 	task = stmf_task_alloc(ict->ict_sess->ist_lport,
2459 	    ict->ict_sess->ist_stmf_sess, iscsi_tm->lun,
2460 	    0, STMF_TASK_EXT_NONE);
2461 	if (task == NULL) {
2462 		/*
2463 		 * If this happens, either the LU is in reset, couldn't
2464 		 * get memory, or some other condition in which we simply
2465 		 * can't complete this request.  It would be nice to return
2466 		 * an error code like "busy" but the closest we have is
2467 		 * "rejected".
2468 		 */
2469 		iscsit_send_task_mgmt_resp(tm_resp_pdu,
2470 		    SCSI_TCP_TM_RESP_REJECTED);
2471 		iscsit_tm_task_free(tm_itask);
2472 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2473 		return;
2474 	}
2475 
2476 	tm_itask->it_tm_pdu = tm_resp_pdu;
2477 	tm_itask->it_stmf_task = task;
2478 	task->task_port_private = tm_itask;
2479 	task->task_mgmt_function = tm_func;
2480 	task->task_additional_flags = TASK_AF_NO_EXPECTED_XFER_LENGTH;
2481 	task->task_priority = 0;
2482 	task->task_max_nbufs = STMF_BUFS_MAX;
2483 	task->task_cmd_seq_no = iscsi_tm->itt;
2484 	task->task_expected_xfer_length = 0;
2485 
2486 	stmf_post_task(task, NULL);
2487 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2488 }
2489 
2490 static void
2491 iscsit_pdu_op_noop(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2492 {
2493 	iscsi_nop_out_hdr_t *out = (iscsi_nop_out_hdr_t *)rx_pdu->isp_hdr;
2494 	iscsi_nop_in_hdr_t *in;
2495 	int resp_datalen;
2496 	idm_pdu_t *resp;
2497 
2498 	/* Ignore the response from initiator */
2499 	if ((out->itt == ISCSI_RSVD_TASK_TAG) ||
2500 	    (out->ttt != ISCSI_RSVD_TASK_TAG)) {
2501 		idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2502 		return;
2503 	}
2504 
2505 	/* Allocate a PDU to respond */
2506 	resp_datalen = ntoh24(out->dlength);
2507 	resp = idm_pdu_alloc(sizeof (iscsi_hdr_t), resp_datalen);
2508 	idm_pdu_init(resp, ict->ict_ic, NULL, NULL);
2509 	if (resp_datalen > 0) {
2510 		bcopy(rx_pdu->isp_data, resp->isp_data, resp_datalen);
2511 	}
2512 
2513 	/*
2514 	 * When sending a NOP-In as a response to a NOP-Out from the initiator,
2515 	 * the target must respond with the same initiator task tag that was
2516 	 * provided in the NOP-Out request, the target transfer tag must be
2517 	 * ISCSI_RSVD_TASK_TAG (0xffffffff) and StatSN will contain the next
2518 	 * status sequence number. The StatSN for the connection is advanced
2519 	 * after this PDU is sent.
2520 	 */
2521 	in = (iscsi_nop_in_hdr_t *)resp->isp_hdr;
2522 	bzero(in, sizeof (*in));
2523 	in->opcode = ISCSI_OP_NOOP_IN;
2524 	in->flags = ISCSI_FLAG_FINAL;
2525 	bcopy(out->lun, in->lun, 8);
2526 	in->itt		= out->itt;
2527 	in->ttt		= ISCSI_RSVD_TASK_TAG;
2528 	hton24(in->dlength, resp_datalen);
2529 	resp->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2530 	/* Any other field in resp to be set? */
2531 	iscsit_pdu_tx(resp);
2532 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2533 }
2534 
2535 static void
2536 iscsit_pdu_op_login_cmd(iscsit_conn_t	*ict, idm_pdu_t *rx_pdu)
2537 {
2538 
2539 	/*
2540 	 * Submit PDU to login state machine.  State machine will free the
2541 	 * PDU.
2542 	 */
2543 	iscsit_login_sm_event(ict, ILE_LOGIN_RCV, rx_pdu);
2544 }
2545 
2546 void
2547 iscsit_pdu_op_logout_cmd(iscsit_conn_t	*ict, idm_pdu_t *rx_pdu)
2548 {
2549 	iscsi_logout_hdr_t 	*logout_req =
2550 	    (iscsi_logout_hdr_t *)rx_pdu->isp_hdr;
2551 	iscsi_logout_rsp_hdr_t	*logout_rsp;
2552 	idm_pdu_t *resp;
2553 
2554 	/* Allocate a PDU to respond */
2555 	resp = idm_pdu_alloc(sizeof (iscsi_hdr_t), 0);
2556 	idm_pdu_init(resp, ict->ict_ic, NULL, NULL);
2557 	/*
2558 	 * The StatSN is to be sent to the initiator,
2559 	 * it is not required to increment the number
2560 	 * as the connection is terminating.
2561 	 */
2562 	resp->isp_flags |= IDM_PDU_SET_STATSN;
2563 	/*
2564 	 * Logout results in the immediate termination of all tasks except
2565 	 * if the logout reason is ISCSI_LOGOUT_REASON_RECOVERY.  The
2566 	 * connection state machine will drive this task cleanup automatically
2567 	 * so we don't need to handle that here.
2568 	 */
2569 	logout_rsp = (iscsi_logout_rsp_hdr_t *)resp->isp_hdr;
2570 	bzero(logout_rsp, sizeof (*logout_rsp));
2571 	logout_rsp->opcode = ISCSI_OP_LOGOUT_RSP;
2572 	logout_rsp->flags = ISCSI_FLAG_FINAL;
2573 	logout_rsp->itt = logout_req->itt;
2574 	if ((logout_req->flags & ISCSI_FLAG_LOGOUT_REASON_MASK) >
2575 	    ISCSI_LOGOUT_REASON_RECOVERY) {
2576 		logout_rsp->response = ISCSI_LOGOUT_RECOVERY_UNSUPPORTED;
2577 	} else {
2578 		logout_rsp->response = ISCSI_LOGOUT_SUCCESS;
2579 	}
2580 
2581 	iscsit_pdu_tx(resp);
2582 	idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
2583 }
2584 
2585 /*
2586  * Calculate the number of outstanding commands we can process
2587  */
2588 int
2589 iscsit_cmd_window()
2590 {
2591 	/*
2592 	 * Instead of using a pre-defined constant for the command window,
2593 	 * it should be made confiurable and dynamic. With MC/S, sequence
2594 	 * numbers will be used up at a much faster rate than with SC/S.
2595 	 */
2596 	return	(ISCSIT_MAX_WINDOW);
2597 }
2598 
2599 /*
2600  * Set local registers based on incoming PDU
2601  */
2602 void
2603 iscsit_set_cmdsn(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
2604 {
2605 	iscsit_sess_t *ist;
2606 	iscsi_scsi_cmd_hdr_t *req;
2607 
2608 	ist = ict->ict_sess;
2609 
2610 	req = (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
2611 	if (req->opcode & ISCSI_OP_IMMEDIATE) {
2612 		/* no cmdsn increment for immediate PDUs */
2613 		return;
2614 	}
2615 
2616 	/* Ensure that the ExpCmdSN advances in an orderly manner */
2617 	mutex_enter(&ist->ist_sn_mutex);
2618 	ist->ist_expcmdsn = ntohl(req->cmdsn) + 1;
2619 	ist->ist_maxcmdsn = ntohl(req->cmdsn) + iscsit_cmd_window();
2620 	mutex_exit(&ist->ist_sn_mutex);
2621 }
2622 
2623 /*
2624  * Wrapper funtion, calls iscsi_calc_rspsn and idm_pdu_tx
2625  */
2626 void
2627 iscsit_pdu_tx(idm_pdu_t *pdu)
2628 {
2629 	iscsit_conn_t *ict = pdu->isp_ic->ic_handle;
2630 	iscsi_scsi_rsp_hdr_t *rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
2631 	iscsit_sess_t *ist = ict->ict_sess;
2632 
2633 	/*
2634 	 * The command sequence numbers are session-wide and must stay
2635 	 * consistent across the transfer, so protect the cmdsn with a
2636 	 * mutex lock on the session. The status sequence number will
2637 	 * be updated just before the transport layer transmits the PDU.
2638 	 */
2639 
2640 	mutex_enter(&ict->ict_sess->ist_sn_mutex);
2641 	/* Set ExpCmdSN and MaxCmdSN */
2642 	rsp->maxcmdsn = htonl(ist->ist_maxcmdsn);
2643 	rsp->expcmdsn = htonl(ist->ist_expcmdsn);
2644 	idm_pdu_tx(pdu);
2645 	mutex_exit(&ict->ict_sess->ist_sn_mutex);
2646 }
2647 
2648 /*
2649  * Internal functions
2650  */
2651 
2652 void
2653 iscsit_send_async_event(iscsit_conn_t *ict, uint8_t event)
2654 {
2655 	idm_pdu_t		*abt;
2656 	iscsi_async_evt_hdr_t	*async_abt;
2657 
2658 	/*
2659 	 * Get a PDU to build the abort request.
2660 	 */
2661 	abt = idm_pdu_alloc(sizeof (iscsi_hdr_t), 0);
2662 	if (abt == NULL) {
2663 		idm_conn_event(ict->ict_ic, CE_TRANSPORT_FAIL, NULL);
2664 		return;
2665 	}
2666 
2667 	/*
2668 	 * A asynchronous message is sent by the target to request a logout.
2669 	 * The StatSN for the connection is advanced after the PDU is sent
2670 	 * to allow for initiator and target state synchronization.
2671 	 */
2672 	idm_pdu_init(abt, ict->ict_ic, NULL, NULL);
2673 	abt->isp_datalen = 0;
2674 	abt->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2675 
2676 	async_abt = (iscsi_async_evt_hdr_t *)abt->isp_hdr;
2677 	bzero(async_abt, sizeof (*async_abt));
2678 	async_abt->opcode = ISCSI_OP_ASYNC_EVENT;
2679 	async_abt->async_event = event;
2680 	async_abt->flags = ISCSI_FLAG_FINAL;
2681 	async_abt->rsvd4[0] = 0xff;
2682 	async_abt->rsvd4[1] = 0xff;
2683 	async_abt->rsvd4[2] = 0xff;
2684 	async_abt->rsvd4[3] = 0xff;
2685 
2686 	switch (event) {
2687 	case ISCSI_ASYNC_EVENT_REQUEST_LOGOUT:
2688 		async_abt->param3 = htons(IDM_LOGOUT_SECONDS);
2689 		break;
2690 	case ISCSI_ASYNC_EVENT_SCSI_EVENT:
2691 	case ISCSI_ASYNC_EVENT_DROPPING_CONNECTION:
2692 	case ISCSI_ASYNC_EVENT_DROPPING_ALL_CONNECTIONS:
2693 	case ISCSI_ASYNC_EVENT_PARAM_NEGOTIATION:
2694 	default:
2695 		ASSERT(0);
2696 	}
2697 
2698 	iscsit_pdu_tx(abt);
2699 }
2700 
2701 void
2702 iscsit_send_reject(iscsit_conn_t *ict, idm_pdu_t *rejected_pdu, uint8_t reason)
2703 {
2704 	idm_pdu_t		*reject_pdu;
2705 	iscsi_reject_rsp_hdr_t	*reject;
2706 
2707 	/*
2708 	 * Get a PDU to build the abort request.
2709 	 */
2710 	reject_pdu = idm_pdu_alloc(sizeof (iscsi_hdr_t),
2711 	    rejected_pdu->isp_hdrlen);
2712 	if (reject_pdu == NULL) {
2713 		idm_conn_event(ict->ict_ic, CE_TRANSPORT_FAIL, NULL);
2714 		return;
2715 	}
2716 	idm_pdu_init(reject_pdu, ict->ict_ic, NULL, NULL);
2717 	/* StatSN is advanced after a Reject PDU */
2718 	reject_pdu->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
2719 	reject_pdu->isp_datalen = rejected_pdu->isp_hdrlen;
2720 	bcopy(rejected_pdu->isp_hdr, reject_pdu->isp_data,
2721 	    rejected_pdu->isp_hdrlen);
2722 
2723 	reject = (iscsi_reject_rsp_hdr_t *)reject_pdu->isp_hdr;
2724 	bzero(reject, sizeof (*reject));
2725 	reject->opcode = ISCSI_OP_REJECT_MSG;
2726 	reject->reason = reason;
2727 	reject->flags = ISCSI_FLAG_FINAL;
2728 	hton24(reject->dlength, rejected_pdu->isp_hdrlen);
2729 	reject->must_be_ff[0] = 0xff;
2730 	reject->must_be_ff[1] = 0xff;
2731 	reject->must_be_ff[2] = 0xff;
2732 	reject->must_be_ff[3] = 0xff;
2733 
2734 	iscsit_pdu_tx(reject_pdu);
2735 }
2736 
2737 
2738 static iscsit_task_t *
2739 iscsit_task_alloc(iscsit_conn_t *ict)
2740 {
2741 	iscsit_task_t *itask;
2742 	iscsit_buf_t *immed_ibuf;
2743 
2744 	/*
2745 	 * Possible items to pre-alloc if we cache iscsit_task_t's:
2746 	 *
2747 	 * Status PDU w/ sense buffer
2748 	 * stmf_data_buf_t for immediate data
2749 	 */
2750 	itask = kmem_alloc(sizeof (iscsit_task_t) + sizeof (iscsit_buf_t) +
2751 	    sizeof (stmf_data_buf_t), KM_NOSLEEP);
2752 	if (itask != NULL) {
2753 		mutex_init(&itask->it_mutex, NULL, MUTEX_DRIVER, NULL);
2754 		itask->it_aborted = itask->it_stmf_abort =
2755 		    itask->it_tm_task = 0;
2756 
2757 		immed_ibuf = (iscsit_buf_t *)(itask + 1);
2758 		bzero(immed_ibuf, sizeof (*immed_ibuf));
2759 		immed_ibuf->ibuf_is_immed = B_TRUE;
2760 		immed_ibuf->ibuf_stmf_buf = (stmf_data_buf_t *)(immed_ibuf + 1);
2761 
2762 		bzero(immed_ibuf->ibuf_stmf_buf, sizeof (stmf_data_buf_t));
2763 		immed_ibuf->ibuf_stmf_buf->db_port_private = immed_ibuf;
2764 		immed_ibuf->ibuf_stmf_buf->db_sglist_length = 1;
2765 		immed_ibuf->ibuf_stmf_buf->db_flags = DB_DIRECTION_FROM_RPORT |
2766 		    DB_DONT_CACHE;
2767 		itask->it_immed_data = immed_ibuf;
2768 		itask->it_idm_task = idm_task_alloc(ict->ict_ic);
2769 		if (itask->it_idm_task != NULL) {
2770 			itask->it_idm_task->idt_private = itask;
2771 			itask->it_ict = ict;
2772 			itask->it_ttt = itask->it_idm_task->idt_tt;
2773 			return (itask);
2774 		} else {
2775 			kmem_free(itask, sizeof (iscsit_task_t) +
2776 			    sizeof (iscsit_buf_t) + sizeof (stmf_data_buf_t));
2777 		}
2778 	}
2779 
2780 	return (NULL);
2781 }
2782 
2783 static void
2784 iscsit_task_free(iscsit_task_t *itask)
2785 {
2786 	idm_task_free(itask->it_idm_task);
2787 	mutex_destroy(&itask->it_mutex);
2788 	kmem_free(itask, sizeof (iscsit_task_t) +
2789 	    sizeof (iscsit_buf_t) + sizeof (stmf_data_buf_t));
2790 }
2791 
2792 static iscsit_task_t *
2793 iscsit_tm_task_alloc(iscsit_conn_t *ict)
2794 {
2795 	iscsit_task_t *itask;
2796 
2797 	itask = kmem_zalloc(sizeof (iscsit_task_t), KM_NOSLEEP);
2798 	if (itask != NULL) {
2799 		idm_conn_hold(ict->ict_ic);
2800 		mutex_init(&itask->it_mutex, NULL, MUTEX_DRIVER, NULL);
2801 		itask->it_aborted = itask->it_stmf_abort =
2802 		    itask->it_tm_responded = 0;
2803 		itask->it_tm_pdu = NULL;
2804 		itask->it_tm_task = 1;
2805 		itask->it_ict = ict;
2806 	}
2807 
2808 	return (itask);
2809 }
2810 
2811 static void
2812 iscsit_tm_task_free(iscsit_task_t *itask)
2813 {
2814 	/*
2815 	 * If we responded then the call to idm_pdu_complete will free the
2816 	 * PDU.  Otherwise we got aborted before the TM function could
2817 	 * complete and we need to free the PDU explicitly.
2818 	 */
2819 	if (itask->it_tm_pdu != NULL && !itask->it_tm_responded)
2820 		idm_pdu_free(itask->it_tm_pdu);
2821 	idm_conn_rele(itask->it_ict->ict_ic);
2822 	mutex_destroy(&itask->it_mutex);
2823 	kmem_free(itask, sizeof (iscsit_task_t));
2824 }
2825 
2826 static idm_status_t
2827 iscsit_task_start(iscsit_task_t *itask)
2828 {
2829 	iscsit_sess_t *ist = itask->it_ict->ict_sess;
2830 	avl_index_t		where;
2831 
2832 	/*
2833 	 * Sanity check the ITT and ensure that this task does not already
2834 	 * exist.  If not then add the task to the session task list.
2835 	 */
2836 	mutex_enter(&ist->ist_mutex);
2837 	mutex_enter(&itask->it_mutex);
2838 	itask->it_active = 1;
2839 	if (avl_find(&ist->ist_task_list, itask, &where) == NULL) {
2840 		/* New task, add to AVL */
2841 		avl_insert(&ist->ist_task_list, itask, where);
2842 		mutex_exit(&itask->it_mutex);
2843 		mutex_exit(&ist->ist_mutex);
2844 		return (IDM_STATUS_SUCCESS);
2845 	}
2846 	mutex_exit(&itask->it_mutex);
2847 	mutex_exit(&ist->ist_mutex);
2848 
2849 	return (IDM_STATUS_REJECT);
2850 }
2851 
2852 static void
2853 iscsit_task_done(iscsit_task_t *itask)
2854 {
2855 	iscsit_sess_t *ist = itask->it_ict->ict_sess;
2856 
2857 	mutex_enter(&ist->ist_mutex);
2858 	mutex_enter(&itask->it_mutex);
2859 	if (itask->it_active) {
2860 		avl_remove(&ist->ist_task_list, itask);
2861 		itask->it_active = 0;
2862 	}
2863 	mutex_exit(&itask->it_mutex);
2864 	mutex_exit(&ist->ist_mutex);
2865 }
2866 
2867 /*
2868  * iscsit status PDU cache
2869  */
2870 
2871 /*ARGSUSED*/
2872 static int
2873 iscsit_status_pdu_constructor(void *pdu_void, void *arg, int flags)
2874 {
2875 	idm_pdu_t *pdu = pdu_void;
2876 	iscsi_scsi_rsp_hdr_t *rsp;
2877 
2878 	bzero(pdu, sizeof (idm_pdu_t));
2879 	pdu->isp_callback = iscsit_send_good_status_done;
2880 	pdu->isp_magic = IDM_PDU_MAGIC;
2881 	pdu->isp_hdr = (iscsi_hdr_t *)(pdu + 1); /* Ptr arithmetic */
2882 	pdu->isp_hdrlen = sizeof (iscsi_hdr_t);
2883 
2884 	/* Setup status response */
2885 	rsp = (iscsi_scsi_rsp_hdr_t *)pdu->isp_hdr;
2886 	bzero(rsp, sizeof (*rsp));
2887 	rsp->opcode = ISCSI_OP_SCSI_RSP;
2888 	rsp->flags = ISCSI_FLAG_FINAL;
2889 	rsp->response = ISCSI_STATUS_CMD_COMPLETED;
2890 
2891 	return (0);
2892 }
2893 
2894 /*
2895  * iscsit private data handler
2896  */
2897 
2898 /*ARGSUSED*/
2899 static void
2900 iscsit_pp_cb(struct stmf_port_provider *pp, int cmd, void *arg, uint32_t flags)
2901 {
2902 	it_config_t		*cfg;
2903 	nvlist_t		*nvl;
2904 	iscsit_service_enabled_t	old_state;
2905 
2906 	if ((cmd != STMF_PROVIDER_DATA_UPDATED) || (arg == NULL)) {
2907 		return;
2908 	}
2909 
2910 	nvl = (nvlist_t *)arg;
2911 
2912 	/* Translate nvlist */
2913 	if (it_nv_to_config(nvl, &cfg) != 0) {
2914 		cmn_err(CE_WARN, "Configuration is invalid");
2915 		return;
2916 	}
2917 
2918 	/* Check that no iSCSI ioctl is currently running */
2919 	mutex_enter(&iscsit_global.global_state_mutex);
2920 	old_state = iscsit_global.global_svc_state;
2921 	switch (iscsit_global.global_svc_state) {
2922 	case ISE_ENABLED:
2923 	case ISE_DISABLED:
2924 		iscsit_global.global_svc_state = ISE_BUSY;
2925 		break;
2926 	case ISE_ENABLING:
2927 		/*
2928 		 * It is OK for the iscsit_pp_cb to be called from inside of
2929 		 * an iSCSI ioctl only if we are currently executing inside
2930 		 * of stmf_register_port_provider.
2931 		 */
2932 		ASSERT((flags & STMF_PCB_PREG_COMPLETE) != 0);
2933 		break;
2934 	default:
2935 		cmn_err(CE_WARN, "iscsit_pp_cb called when global_svc_state"
2936 		    " is not ENABLED(0x%x) -- ignoring",
2937 		    iscsit_global.global_svc_state);
2938 		mutex_exit(&iscsit_global.global_state_mutex);
2939 		it_config_free_cmn(cfg);
2940 		return;
2941 	}
2942 	mutex_exit(&iscsit_global.global_state_mutex);
2943 
2944 	/* Update config */
2945 	(void) iscsit_config_merge(cfg);
2946 
2947 	it_config_free_cmn(cfg);
2948 
2949 	/* Restore old iSCSI driver global state */
2950 	mutex_enter(&iscsit_global.global_state_mutex);
2951 	ASSERT(iscsit_global.global_svc_state == ISE_BUSY ||
2952 	    iscsit_global.global_svc_state == ISE_ENABLING);
2953 	iscsit_global.global_svc_state = old_state;
2954 	mutex_exit(&iscsit_global.global_state_mutex);
2955 }
2956 
2957 
2958 static it_cfg_status_t
2959 iscsit_config_merge(it_config_t *in_cfg)
2960 {
2961 	it_cfg_status_t	status;
2962 	it_config_t	*cfg;
2963 	it_config_t	tmp_cfg;
2964 	list_t		tpg_del_list;
2965 
2966 	if (in_cfg) {
2967 		cfg = in_cfg;
2968 	} else {
2969 		/* Make empty config */
2970 		bzero(&tmp_cfg, sizeof (tmp_cfg));
2971 		cfg = &tmp_cfg;
2972 	}
2973 
2974 	list_create(&tpg_del_list,  sizeof (iscsit_tpg_t),
2975 	    offsetof(iscsit_tpg_t, tpg_delete_ln));
2976 
2977 	/*
2978 	 * Update targets, initiator contexts, target portal groups,
2979 	 * and iSNS client
2980 	 */
2981 	ISCSIT_GLOBAL_LOCK(RW_WRITER);
2982 	if (((status = iscsit_config_merge_tpg(cfg, &tpg_del_list))
2983 	    != 0) ||
2984 	    ((status = iscsit_config_merge_tgt(cfg)) != 0) ||
2985 	    ((status = iscsit_config_merge_ini(cfg)) != 0) ||
2986 	    ((status = isnst_config_merge(cfg)) != 0)) {
2987 		ISCSIT_GLOBAL_UNLOCK();
2988 		return (status);
2989 	}
2990 
2991 	/* Update other global config parameters */
2992 	if (iscsit_global.global_props) {
2993 		nvlist_free(iscsit_global.global_props);
2994 		iscsit_global.global_props = NULL;
2995 	}
2996 	if (in_cfg) {
2997 		(void) nvlist_dup(cfg->config_global_properties,
2998 		    &iscsit_global.global_props, KM_SLEEP);
2999 	}
3000 	ISCSIT_GLOBAL_UNLOCK();
3001 
3002 	iscsit_config_destroy_tpgs(&tpg_del_list);
3003 
3004 	list_destroy(&tpg_del_list);
3005 
3006 	return (ITCFG_SUCCESS);
3007 }
3008 
3009 /*
3010  * iscsit_sna_lt[e]
3011  *
3012  * Compare serial numbers using serial number arithmetic as defined in
3013  * RFC 1982.
3014  *
3015  * NOTE: This code is duplicated in the isns server. It ought to be common.
3016  */
3017 
3018 static int
3019 iscsit_sna_lt(uint32_t sn1, uint32_t sn2)
3020 {
3021 	return ((sn1 != sn2) &&
3022 	    (((sn1 < sn2) && ((sn2 - sn1) < ISCSIT_SNA32_CHECK)) ||
3023 	    ((sn1 > sn2) && ((sn1 - sn2) > ISCSIT_SNA32_CHECK))));
3024 }
3025 
3026 static int
3027 iscsit_sna_lte(uint32_t sn1, uint32_t sn2)
3028 {
3029 	return ((sn1 == sn2) ||
3030 	    (((sn1 < sn2) && ((sn2 - sn1) < ISCSIT_SNA32_CHECK)) ||
3031 	    ((sn1 > sn2) && ((sn1 - sn2) > ISCSIT_SNA32_CHECK))));
3032 }
3033 
3034 
3035 static boolean_t
3036 iscsit_cmdsn_in_window(iscsit_conn_t *ict, uint32_t cmdsn)
3037 {
3038 	iscsit_sess_t	*ist = ict->ict_sess;
3039 	int		rval = B_TRUE;
3040 
3041 	ist = ict->ict_sess;
3042 
3043 	mutex_enter(&ist->ist_sn_mutex);
3044 
3045 	/*
3046 	 * If cmdsn is less than ist_expcmdsn - iscsit_cmd_window() or
3047 	 * greater than ist_expcmdsn, it's not in the window.
3048 	 */
3049 
3050 	if (iscsit_sna_lt(cmdsn, (ist->ist_expcmdsn - iscsit_cmd_window())) ||
3051 	    !iscsit_sna_lte(cmdsn, ist->ist_expcmdsn)) {
3052 		rval = B_FALSE;
3053 	}
3054 
3055 	mutex_exit(&ist->ist_sn_mutex);
3056 
3057 	return (rval);
3058 }
3059 
3060 /*
3061  * iscsit_check_cmdsn_and_queue
3062  *
3063  * Independent of the order in which the iSCSI target receives non-immediate
3064  * command PDU across the entire session and any multiple connections within
3065  * the session, the target must deliver the commands to the SCSI layer in
3066  * CmdSN order. So out-of-order non-immediate commands are queued up on a
3067  * session-wide wait queue. Duplicate commands are ignored.
3068  *
3069  */
3070 static int
3071 iscsit_check_cmdsn_and_queue(idm_pdu_t *rx_pdu)
3072 {
3073 	idm_conn_t		*ic = rx_pdu->isp_ic;
3074 	iscsit_conn_t		*ict = ic->ic_handle;
3075 	iscsit_sess_t		*ist = ict->ict_sess;
3076 	iscsi_scsi_cmd_hdr_t	*hdr = (iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr;
3077 
3078 	mutex_enter(&ist->ist_sn_mutex);
3079 	if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
3080 		/* do not queue, handle it immediately */
3081 		DTRACE_PROBE2(immediate__cmd, iscsit_sess_t *, ist,
3082 		    idm_pdu_t *, rx_pdu);
3083 		mutex_exit(&ist->ist_sn_mutex);
3084 		return (ISCSIT_CMDSN_EQ_EXPCMDSN);
3085 	}
3086 	if (iscsit_sna_lt(ist->ist_expcmdsn, ntohl(hdr->cmdsn))) {
3087 		/*
3088 		 * Out-of-order commands (cmdSN higher than ExpCmdSN)
3089 		 * are staged on a fixed-size circular buffer until
3090 		 * the missing command is delivered to the SCSI layer.
3091 		 * Irrespective of the order of insertion into the
3092 		 * staging queue, the commands are processed out of the
3093 		 * queue in cmdSN order only.
3094 		 */
3095 		rx_pdu->isp_queue_time = ddi_get_time();
3096 		iscsit_add_pdu_to_queue(ist, rx_pdu);
3097 		mutex_exit(&ist->ist_sn_mutex);
3098 		return (ISCSIT_CMDSN_GT_EXPCMDSN);
3099 	} else if (iscsit_sna_lt(ntohl(hdr->cmdsn), ist->ist_expcmdsn)) {
3100 		DTRACE_PROBE3(cmdsn__lt__expcmdsn, iscsit_sess_t *, ist,
3101 		    iscsit_conn_t *, ict, idm_pdu_t *, rx_pdu);
3102 		mutex_exit(&ist->ist_sn_mutex);
3103 		return (ISCSIT_CMDSN_LT_EXPCMDSN);
3104 	} else {
3105 		mutex_exit(&ist->ist_sn_mutex);
3106 		return (ISCSIT_CMDSN_EQ_EXPCMDSN);
3107 	}
3108 }
3109 
3110 /*
3111  * iscsit_add_pdu_to_queue() adds PDUs into the array indexed by
3112  * their cmdsn value. The length of the array is kept above the
3113  * maximum window size. The window keeps the cmdsn within a range
3114  * such that there are no collisons. e.g. the assumption is that
3115  * the windowing checks make it impossible to receive PDUs that
3116  * index into the same location in the array.
3117  */
3118 static void
3119 iscsit_add_pdu_to_queue(iscsit_sess_t *ist, idm_pdu_t *rx_pdu)
3120 {
3121 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3122 	iscsit_conn_t	*ict 	= rx_pdu->isp_ic->ic_handle;
3123 	uint32_t	cmdsn	=
3124 	    ((iscsi_scsi_cmd_hdr_t *)rx_pdu->isp_hdr)->cmdsn;
3125 	uint32_t	index;
3126 
3127 	ASSERT(MUTEX_HELD(&ist->ist_sn_mutex));
3128 	/*
3129 	 * If the connection is being torn down, then
3130 	 * don't add the PDU to the staging queue
3131 	 */
3132 	mutex_enter(&ict->ict_mutex);
3133 	if (ict->ict_lost) {
3134 		mutex_exit(&ict->ict_mutex);
3135 		idm_pdu_complete(rx_pdu, IDM_STATUS_FAIL);
3136 		return;
3137 	}
3138 	iscsit_conn_dispatch_hold(ict);
3139 	mutex_exit(&ict->ict_mutex);
3140 
3141 	index = ntohl(cmdsn) % ISCSIT_RXPDU_QUEUE_LEN;
3142 	ASSERT(cbuf->cb_buffer[index] == NULL);
3143 	cbuf->cb_buffer[index] = rx_pdu;
3144 	cbuf->cb_num_elems++;
3145 }
3146 
3147 static idm_pdu_t *
3148 iscsit_remove_pdu_from_queue(iscsit_sess_t *ist, uint32_t cmdsn)
3149 {
3150 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3151 	idm_pdu_t	*pdu	= NULL;
3152 	uint32_t	index;
3153 
3154 	ASSERT(MUTEX_HELD(&ist->ist_sn_mutex));
3155 	index = cmdsn % ISCSIT_RXPDU_QUEUE_LEN;
3156 	if ((pdu = cbuf->cb_buffer[index]) != NULL) {
3157 		ASSERT(cmdsn ==
3158 		    ntohl(((iscsi_scsi_cmd_hdr_t *)pdu->isp_hdr)->cmdsn));
3159 		cbuf->cb_buffer[index] = NULL;
3160 		cbuf->cb_num_elems--;
3161 		return (pdu);
3162 	}
3163 	return (NULL);
3164 }
3165 
3166 /*
3167  * iscsit_process_pdu_in_queue() finds the next pdu in sequence
3168  * and posts it to the SCSI layer
3169  */
3170 static void
3171 iscsit_process_pdu_in_queue(iscsit_sess_t *ist)
3172 {
3173 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3174 	idm_pdu_t	*pdu = NULL;
3175 	uint32_t	expcmdsn;
3176 
3177 	for (;;) {
3178 		mutex_enter(&ist->ist_sn_mutex);
3179 		if (cbuf->cb_num_elems == 0) {
3180 			mutex_exit(&ist->ist_sn_mutex);
3181 			break;
3182 		}
3183 		expcmdsn = ist->ist_expcmdsn;
3184 		if ((pdu = iscsit_remove_pdu_from_queue(ist, expcmdsn))
3185 		    == NULL) {
3186 			mutex_exit(&ist->ist_sn_mutex);
3187 			break;
3188 		}
3189 		mutex_exit(&ist->ist_sn_mutex);
3190 		iscsit_post_staged_pdu(pdu);
3191 	}
3192 }
3193 
3194 static void
3195 iscsit_post_staged_pdu(idm_pdu_t *rx_pdu)
3196 {
3197 	iscsit_conn_t	*ict	= rx_pdu->isp_ic->ic_handle;
3198 
3199 	/* Post the PDU to the SCSI layer */
3200 	switch (IDM_PDU_OPCODE(rx_pdu)) {
3201 	case ISCSI_OP_NOOP_OUT:
3202 		iscsit_set_cmdsn(ict, rx_pdu);
3203 		iscsit_pdu_op_noop(ict, rx_pdu);
3204 		break;
3205 	case ISCSI_OP_TEXT_CMD:
3206 		iscsit_set_cmdsn(ict, rx_pdu);
3207 		iscsit_pdu_op_text_cmd(ict, rx_pdu);
3208 		break;
3209 	case ISCSI_OP_SCSI_TASK_MGT_MSG:
3210 		iscsit_set_cmdsn(ict, rx_pdu);
3211 		iscsit_op_scsi_task_mgmt(ict, rx_pdu);
3212 		break;
3213 	case ISCSI_OP_SCSI_CMD:
3214 		/* cmdSN will be incremented after creating itask */
3215 		iscsit_post_scsi_cmd(rx_pdu->isp_ic, rx_pdu);
3216 		break;
3217 	case ISCSI_OP_LOGOUT_CMD:
3218 		iscsit_set_cmdsn(ict, rx_pdu);
3219 		iscsit_pdu_op_logout_cmd(ict, rx_pdu);
3220 		break;
3221 	default:
3222 		/* No other PDUs should be placed on the queue */
3223 		ASSERT(0);
3224 	}
3225 	iscsit_conn_dispatch_rele(ict); /* release hold on the conn */
3226 }
3227 
3228 /* ARGSUSED */
3229 void
3230 iscsit_rxpdu_queue_monitor_start(void)
3231 {
3232 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3233 	if (iscsit_rxpdu_queue_monitor_thr_running) {
3234 		mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3235 		return;
3236 	}
3237 	iscsit_rxpdu_queue_monitor_thr_id =
3238 	    thread_create(NULL, 0, iscsit_rxpdu_queue_monitor, NULL,
3239 	    0, &p0, TS_RUN, minclsyspri);
3240 	while (!iscsit_rxpdu_queue_monitor_thr_running) {
3241 		cv_wait(&iscsit_rxpdu_queue_monitor_cv,
3242 		    &iscsit_rxpdu_queue_monitor_mutex);
3243 	}
3244 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3245 
3246 }
3247 
3248 /* ARGSUSED */
3249 void
3250 iscsit_rxpdu_queue_monitor_stop(void)
3251 {
3252 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3253 	if (iscsit_rxpdu_queue_monitor_thr_running) {
3254 		iscsit_rxpdu_queue_monitor_thr_running = B_FALSE;
3255 		cv_signal(&iscsit_rxpdu_queue_monitor_cv);
3256 		mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3257 
3258 		thread_join(iscsit_rxpdu_queue_monitor_thr_did);
3259 		return;
3260 	}
3261 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3262 }
3263 
3264 /*
3265  * A separate thread is used to scan the staging queue on all the
3266  * sessions, If a delayed PDU does not arrive within a timeout, the
3267  * target will advance to the staged PDU that is next in sequence
3268  * and exceeded the threshold wait time. It is up to the initiator
3269  * to note that the target has not acknowledged a particular cmdsn
3270  * and take appropriate action.
3271  */
3272 /* ARGSUSED */
3273 static void
3274 iscsit_rxpdu_queue_monitor(void *arg)
3275 {
3276 	iscsit_tgt_t	*tgt;
3277 	iscsit_sess_t	*ist;
3278 
3279 	mutex_enter(&iscsit_rxpdu_queue_monitor_mutex);
3280 	iscsit_rxpdu_queue_monitor_thr_did = curthread->t_did;
3281 	iscsit_rxpdu_queue_monitor_thr_running = B_TRUE;
3282 	cv_signal(&iscsit_rxpdu_queue_monitor_cv);
3283 
3284 	while (iscsit_rxpdu_queue_monitor_thr_running) {
3285 		ISCSIT_GLOBAL_LOCK(RW_READER);
3286 		for (tgt = avl_first(&iscsit_global.global_target_list);
3287 		    tgt != NULL;
3288 		    tgt = AVL_NEXT(&iscsit_global.global_target_list, tgt)) {
3289 			mutex_enter(&tgt->target_mutex);
3290 			for (ist = avl_first(&tgt->target_sess_list);
3291 			    ist != NULL;
3292 			    ist = AVL_NEXT(&tgt->target_sess_list, ist)) {
3293 
3294 				iscsit_rxpdu_queue_monitor_session(ist);
3295 			}
3296 			mutex_exit(&tgt->target_mutex);
3297 		}
3298 		ISCSIT_GLOBAL_UNLOCK();
3299 		if (iscsit_rxpdu_queue_monitor_thr_running == B_FALSE) {
3300 			break;
3301 		}
3302 		(void) cv_reltimedwait(&iscsit_rxpdu_queue_monitor_cv,
3303 		    &iscsit_rxpdu_queue_monitor_mutex,
3304 		    ISCSIT_RXPDU_QUEUE_MONITOR_INTERVAL * drv_usectohz(1000000),
3305 		    TR_CLOCK_TICK);
3306 	}
3307 	mutex_exit(&iscsit_rxpdu_queue_monitor_mutex);
3308 	thread_exit();
3309 }
3310 
3311 static void
3312 iscsit_rxpdu_queue_monitor_session(iscsit_sess_t *ist)
3313 {
3314 	iscsit_cbuf_t	*cbuf	= ist->ist_rxpdu_queue;
3315 	idm_pdu_t	*next_pdu = NULL;
3316 	uint32_t	index, next_cmdsn, i;
3317 
3318 	/*
3319 	 * Assume that all PDUs in the staging queue have a cmdsn >= expcmdsn.
3320 	 * Starting with the expcmdsn, iterate over the staged PDUs to find
3321 	 * the next PDU with a wait time greater than the threshold. If found
3322 	 * advance the staged PDU to the SCSI layer, skipping over the missing
3323 	 * PDU(s) to get past the hole in the command sequence. It is up to
3324 	 * the initiator to note that the target has not acknowledged a cmdsn
3325 	 * and take appropriate action.
3326 	 *
3327 	 * Since the PDU(s) arrive in any random order, it is possible that
3328 	 * that the actual wait time for a particular PDU is much longer than
3329 	 * the defined threshold. e.g. Consider a case where commands are sent
3330 	 * over 4 different connections, and cmdsn = 1004 arrives first, then
3331 	 * 1003, and 1002 and 1001 are lost due to a connection failure.
3332 	 * So now 1003 is waiting for 1002 to be delivered, and although the
3333 	 * wait time of 1004 > wait time of 1003, only 1003 will be considered
3334 	 * by the monitor thread. 1004 will be automatically processed by
3335 	 * iscsit_process_pdu_in_queue() once the scan is complete and the
3336 	 * expcmdsn becomes current.
3337 	 */
3338 	mutex_enter(&ist->ist_sn_mutex);
3339 	cbuf = ist->ist_rxpdu_queue;
3340 	if (cbuf->cb_num_elems == 0) {
3341 		mutex_exit(&ist->ist_sn_mutex);
3342 		return;
3343 	}
3344 	for (next_pdu = NULL, i = 0; ; i++) {
3345 		next_cmdsn = ist->ist_expcmdsn + i; /* start at expcmdsn */
3346 		index = next_cmdsn % ISCSIT_RXPDU_QUEUE_LEN;
3347 		if ((next_pdu = cbuf->cb_buffer[index]) != NULL) {
3348 			/*
3349 			 * If the PDU wait time has not exceeded threshold
3350 			 * stop scanning the staging queue until the timer
3351 			 * fires again
3352 			 */
3353 			if ((ddi_get_time() - next_pdu->isp_queue_time)
3354 			    < rxpdu_queue_threshold) {
3355 				mutex_exit(&ist->ist_sn_mutex);
3356 				return;
3357 			}
3358 			/*
3359 			 * Remove the next PDU from the queue and post it
3360 			 * to the SCSI layer, skipping over the missing
3361 			 * PDU. Stop scanning the staging queue until
3362 			 * the monitor timer fires again
3363 			 */
3364 			(void) iscsit_remove_pdu_from_queue(ist, next_cmdsn);
3365 			mutex_exit(&ist->ist_sn_mutex);
3366 			DTRACE_PROBE3(advanced__to__blocked__cmdsn,
3367 			    iscsit_sess_t *, ist, idm_pdu_t *, next_pdu,
3368 			    uint32_t, next_cmdsn);
3369 			iscsit_post_staged_pdu(next_pdu);
3370 			/* Deliver any subsequent PDUs immediately */
3371 			iscsit_process_pdu_in_queue(ist);
3372 			return;
3373 		}
3374 		/*
3375 		 * Skipping over i PDUs, e.g. a case where commands 1001 and
3376 		 * 1002 are lost in the network, skip over both and post 1003
3377 		 * expcmdsn then becomes 1004 at the end of the scan.
3378 		 */
3379 		DTRACE_PROBE2(skipping__over__cmdsn, iscsit_sess_t *, ist,
3380 		    uint32_t, next_cmdsn);
3381 	}
3382 	/*
3383 	 * following the assumption, staged cmdsn >= expcmdsn, this statement
3384 	 * is never reached.
3385 	 */
3386 }
3387