Merge from vendor branch GDB:
[dragonfly.git] / sys / bus / cam / scsi / scsi_pass.c
1 /*
2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
3  * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions, and the following disclaimer,
11  *    without modification, immediately at the beginning of the file.
12  * 2. The name of the author may not be used to endorse or promote products
13  *    derived from this software without specific prior written permission.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
19  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD: src/sys/cam/scsi/scsi_pass.c,v 1.19 2000/01/17 06:27:37 mjacob Exp $
28  * $DragonFly: src/sys/bus/cam/scsi/scsi_pass.c,v 1.15 2006/03/24 18:35:27 dillon Exp $
29  */
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/types.h>
35 #include <sys/buf.h>
36 #include <sys/malloc.h>
37 #include <sys/fcntl.h>
38 #include <sys/stat.h>
39 #include <sys/conf.h>
40 #include <sys/buf.h>
41 #include <sys/proc.h>
42 #include <sys/errno.h>
43 #include <sys/devicestat.h>
44 #include <sys/proc.h>
45 #include <sys/buf2.h>
46 #include <sys/thread2.h>
47
48 #include "../cam.h"
49 #include "../cam_ccb.h"
50 #include "../cam_extend.h"
51 #include "../cam_periph.h"
52 #include "../cam_xpt_periph.h"
53 #include "../cam_debug.h"
54
55 #include "scsi_all.h"
56 #include "scsi_message.h"
57 #include "scsi_da.h"
58 #include "scsi_pass.h"
59
60 typedef enum {
61         PASS_FLAG_OPEN                  = 0x01,
62         PASS_FLAG_LOCKED                = 0x02,
63         PASS_FLAG_INVALID               = 0x04
64 } pass_flags;
65
66 typedef enum {
67         PASS_STATE_NORMAL
68 } pass_state;
69
70 typedef enum {
71         PASS_CCB_BUFFER_IO,
72         PASS_CCB_WAITING
73 } pass_ccb_types;
74
75 #define ccb_type        ppriv_field0
76 #define ccb_bio         ppriv_ptr1
77
78 struct pass_softc {
79         pass_state      state;
80         pass_flags      flags;
81         u_int8_t        pd_type;
82         struct          bio_queue_head bio_queue;
83         union ccb       saved_ccb;
84         struct devstat  device_stats;
85 };
86
87 #define PASS_CDEV_MAJOR 31
88
89 static  d_open_t        passopen;
90 static  d_close_t       passclose;
91 static  d_ioctl_t       passioctl;
92 static  d_strategy_t    passstrategy;
93
94 static  periph_init_t   passinit;
95 static  periph_ctor_t   passregister;
96 static  periph_oninv_t  passoninvalidate;
97 static  periph_dtor_t   passcleanup;
98 static  periph_start_t  passstart;
99 static  void            passasync(void *callback_arg, u_int32_t code,
100                                   struct cam_path *path, void *arg);
101 static  void            passdone(struct cam_periph *periph, 
102                                  union ccb *done_ccb);
103 static  int             passerror(union ccb *ccb, u_int32_t cam_flags, 
104                                   u_int32_t sense_flags);
105 static  int             passsendccb(struct cam_periph *periph, union ccb *ccb,
106                                     union ccb *inccb);
107
108 static struct periph_driver passdriver =
109 {
110         passinit, "pass",
111         TAILQ_HEAD_INITIALIZER(passdriver.units), /* generation */ 0
112 };
113
114 DATA_SET(periphdriver_set, passdriver);
115
116 static struct cdevsw pass_cdevsw = {
117         /* name */      "pass",
118         /* maj */       PASS_CDEV_MAJOR,
119         /* flags */     0,
120         /* port */      NULL,
121         /* clone */     NULL,
122
123         /* open */      passopen,
124         /* close */     passclose,
125         /* read */      physread,
126         /* write */     physwrite,
127         /* ioctl */     passioctl,
128         /* poll */      nopoll,
129         /* mmap */      nommap,
130         /* strategy */  passstrategy,
131         /* dump */      nodump,
132         /* psize */     nopsize
133 };
134
135 static struct extend_array *passperiphs;
136
137 static void
138 passinit(void)
139 {
140         cam_status status;
141         struct cam_path *path;
142
143         /*
144          * Create our extend array for storing the devices we attach to.
145          */
146         passperiphs = cam_extend_new();
147         if (passperiphs == NULL) {
148                 printf("passm: Failed to alloc extend array!\n");
149                 return;
150         }
151
152         /*
153          * Install a global async callback.  This callback will
154          * receive async callbacks like "new device found".
155          */
156         status = xpt_create_path(&path, /*periph*/NULL, CAM_XPT_PATH_ID,
157                                  CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
158
159         if (status == CAM_REQ_CMP) {
160                 struct ccb_setasync csa;
161
162                 xpt_setup_ccb(&csa.ccb_h, path, /*priority*/5);
163                 csa.ccb_h.func_code = XPT_SASYNC_CB;
164                 csa.event_enable = AC_FOUND_DEVICE;
165                 csa.callback = passasync;
166                 csa.callback_arg = NULL;
167                 xpt_action((union ccb *)&csa);
168                 status = csa.ccb_h.status;
169                 xpt_free_path(path);
170         }
171
172         if (status != CAM_REQ_CMP) {
173                 printf("pass: Failed to attach master async callback "
174                        "due to status 0x%x!\n", status);
175         }
176         
177 }
178
179 static void
180 passoninvalidate(struct cam_periph *periph)
181 {
182         struct pass_softc *softc;
183         struct buf *q_bp;
184         struct bio *q_bio;
185         struct ccb_setasync csa;
186
187         softc = (struct pass_softc *)periph->softc;
188
189         /*
190          * De-register any async callbacks.
191          */
192         xpt_setup_ccb(&csa.ccb_h, periph->path,
193                       /* priority */ 5);
194         csa.ccb_h.func_code = XPT_SASYNC_CB;
195         csa.event_enable = 0;
196         csa.callback = passasync;
197         csa.callback_arg = periph;
198         xpt_action((union ccb *)&csa);
199
200         softc->flags |= PASS_FLAG_INVALID;
201
202         /*
203          * We need to be in a critical section here to keep the buffer
204          * queue from being modified while we traverse it.
205          */
206         crit_enter();
207
208         /*
209          * Return all queued I/O with ENXIO.
210          * XXX Handle any transactions queued to the card
211          *     with XPT_ABORT_CCB.
212          */
213         while ((q_bio = bioq_first(&softc->bio_queue)) != NULL){
214                 bioq_remove(&softc->bio_queue, q_bio);
215                 q_bp = q_bio->bio_buf;
216                 q_bp->b_resid = q_bp->b_bcount;
217                 q_bp->b_error = ENXIO;
218                 q_bp->b_flags |= B_ERROR;
219                 biodone(q_bio);
220         }
221         crit_exit();
222
223         if (bootverbose) {
224                 xpt_print_path(periph->path);
225                 printf("lost device\n");
226         }
227
228 }
229
230 static void
231 passcleanup(struct cam_periph *periph)
232 {
233         struct pass_softc *softc;
234
235         softc = (struct pass_softc *)periph->softc;
236
237         devstat_remove_entry(&softc->device_stats);
238
239         cam_extend_release(passperiphs, periph->unit_number);
240
241         if (bootverbose) {
242                 xpt_print_path(periph->path);
243                 printf("removing device entry\n");
244         }
245         cdevsw_remove(&pass_cdevsw, -1, periph->unit_number);
246         free(softc, M_DEVBUF);
247 }
248
249 static void
250 passasync(void *callback_arg, u_int32_t code,
251           struct cam_path *path, void *arg)
252 {
253         struct cam_periph *periph;
254
255         periph = (struct cam_periph *)callback_arg;
256
257         switch (code) {
258         case AC_FOUND_DEVICE:
259         {
260                 struct ccb_getdev *cgd;
261                 cam_status status;
262  
263                 cgd = (struct ccb_getdev *)arg;
264
265                 /*
266                  * Allocate a peripheral instance for
267                  * this device and start the probe
268                  * process.
269                  */
270                 status = cam_periph_alloc(passregister, passoninvalidate,
271                                           passcleanup, passstart, "pass",
272                                           CAM_PERIPH_BIO, cgd->ccb_h.path,
273                                           passasync, AC_FOUND_DEVICE, cgd);
274
275                 if (status != CAM_REQ_CMP
276                  && status != CAM_REQ_INPROG)
277                         printf("passasync: Unable to attach new device "
278                                 "due to status 0x%x\n", status);
279
280                 break;
281         }
282         default:
283                 cam_periph_async(periph, code, path, arg);
284                 break;
285         }
286 }
287
288 static cam_status
289 passregister(struct cam_periph *periph, void *arg)
290 {
291         struct pass_softc *softc;
292         struct ccb_setasync csa;
293         struct ccb_getdev *cgd;
294
295         cgd = (struct ccb_getdev *)arg;
296         if (periph == NULL) {
297                 printf("passregister: periph was NULL!!\n");
298                 return(CAM_REQ_CMP_ERR);
299         }
300
301         if (cgd == NULL) {
302                 printf("passregister: no getdev CCB, can't register device\n");
303                 return(CAM_REQ_CMP_ERR);
304         }
305
306         softc = malloc(sizeof(*softc), M_DEVBUF, M_INTWAIT | M_ZERO);
307         softc->state = PASS_STATE_NORMAL;
308         softc->pd_type = SID_TYPE(&cgd->inq_data);
309         bioq_init(&softc->bio_queue);
310
311         periph->softc = softc;
312
313         cam_extend_set(passperiphs, periph->unit_number, periph);
314         /*
315          * We pass in 0 for a blocksize, since we don't 
316          * know what the blocksize of this device is, if 
317          * it even has a blocksize.
318          */
319         devstat_add_entry(&softc->device_stats, "pass", periph->unit_number,
320                           0, DEVSTAT_NO_BLOCKSIZE | DEVSTAT_NO_ORDERED_TAGS,
321                           softc->pd_type |
322                           DEVSTAT_TYPE_IF_SCSI |
323                           DEVSTAT_TYPE_PASS,
324                           DEVSTAT_PRIORITY_PASS);
325
326         /* Register the device */
327         cdevsw_add(&pass_cdevsw, -1, periph->unit_number);
328         make_dev(&pass_cdevsw, periph->unit_number, UID_ROOT,
329                   GID_OPERATOR, 0600, "%s%d", periph->periph_name,
330                   periph->unit_number);
331
332         /*
333          * Add an async callback so that we get
334          * notified if this device goes away.
335          */
336         xpt_setup_ccb(&csa.ccb_h, periph->path, /* priority */ 5);
337         csa.ccb_h.func_code = XPT_SASYNC_CB;
338         csa.event_enable = AC_LOST_DEVICE;
339         csa.callback = passasync;
340         csa.callback_arg = periph;
341         xpt_action((union ccb *)&csa);
342
343         if (bootverbose)
344                 xpt_announce_periph(periph, NULL);
345
346         return(CAM_REQ_CMP);
347 }
348
349 static int
350 passopen(dev_t dev, int flags, int fmt, struct thread *td)
351 {
352         struct cam_periph *periph;
353         struct pass_softc *softc;
354         int unit, error;
355
356         error = 0; /* default to no error */
357
358         /* unit = dkunit(dev); */
359         /* XXX KDM fix this */
360         unit = minor(dev) & 0xff;
361
362         periph = cam_extend_get(passperiphs, unit);
363
364         if (periph == NULL)
365                 return (ENXIO);
366
367         softc = (struct pass_softc *)periph->softc;
368
369         crit_enter();
370         if (softc->flags & PASS_FLAG_INVALID) {
371                 crit_exit();
372                 return(ENXIO);
373         }
374
375         /*
376          * Don't allow access when we're running at a high securelvel.
377          */
378         if (securelevel > 1) {
379                 crit_exit();
380                 return(EPERM);
381         }
382
383         /*
384          * Only allow read-write access.
385          */
386         if (((flags & FWRITE) == 0) || ((flags & FREAD) == 0)) {
387                 crit_exit();
388                 return(EPERM);
389         }
390
391         /*
392          * We don't allow nonblocking access.
393          */
394         if ((flags & O_NONBLOCK) != 0) {
395                 xpt_print_path(periph->path);
396                 printf("can't do nonblocking accesss\n");
397                 crit_exit();
398                 return(EINVAL);
399         }
400
401         if ((error = cam_periph_lock(periph, PCATCH)) != 0) {
402                 crit_exit();
403                 return (error);
404         }
405
406         crit_exit();
407
408         if ((softc->flags & PASS_FLAG_OPEN) == 0) {
409                 if (cam_periph_acquire(periph) != CAM_REQ_CMP)
410                         return(ENXIO);
411                 softc->flags |= PASS_FLAG_OPEN;
412         }
413
414         cam_periph_unlock(periph);
415
416         return (error);
417 }
418
419 static int
420 passclose(dev_t dev, int flag, int fmt, struct thread *td)
421 {
422         struct  cam_periph *periph;
423         struct  pass_softc *softc;
424         int     unit, error;
425
426         /* unit = dkunit(dev); */
427         /* XXX KDM fix this */
428         unit = minor(dev) & 0xff;
429
430         periph = cam_extend_get(passperiphs, unit);
431         if (periph == NULL)
432                 return (ENXIO); 
433
434         softc = (struct pass_softc *)periph->softc;
435
436         if ((error = cam_periph_lock(periph, 0)) != 0)
437                 return (error);
438
439         softc->flags &= ~PASS_FLAG_OPEN;
440
441         cam_periph_unlock(periph);
442         cam_periph_release(periph);
443
444         return (0);
445 }
446
447 /*
448  * Actually translate the requested transfer into one the physical driver
449  * can understand.  The transfer is described by a buf and will include
450  * only one physical transfer.
451  */
452 static void
453 passstrategy(dev_t dev, struct bio *bio)
454 {
455         struct buf *bp = bio->bio_buf;
456         struct cam_periph *periph;
457         struct pass_softc *softc;
458         u_int  unit;
459
460         /*
461          * The read/write interface for the passthrough driver doesn't
462          * really work right now.  So, we just pass back EINVAL to tell the
463          * user to go away.
464          */
465         bp->b_error = EINVAL;
466         goto bad;
467
468         /* unit = dkunit(dev); */
469         /* XXX KDM fix this */
470         unit = minor(dev) & 0xff;
471
472         periph = cam_extend_get(passperiphs, unit);
473         if (periph == NULL) {
474                 bp->b_error = ENXIO;
475                 goto bad;
476         }
477         softc = (struct pass_softc *)periph->softc;
478
479         /*
480          * Odd number of bytes or negative offset
481          */
482         /* valid request?  */
483         if (bio->bio_offset < 0) {
484                 bp->b_error = EINVAL;
485                 goto bad;
486         }
487         
488         /*
489          * Mask interrupts so that the pack cannot be invalidated until
490          * after we are in the queue.  Otherwise, we might not properly
491          * clean up one of the buffers.
492          */
493         crit_enter();
494         bioq_insert_tail(&softc->bio_queue, bio);
495         crit_exit();
496         
497         /*
498          * Schedule ourselves for performing the work.
499          */
500         xpt_schedule(periph, /* XXX priority */1);
501
502         return;
503 bad:
504         bp->b_flags |= B_ERROR;
505
506         /*
507          * Correctly set the buf to indicate a completed xfer
508          */
509         bp->b_resid = bp->b_bcount;
510         biodone(bio);
511 }
512
513 static void
514 passstart(struct cam_periph *periph, union ccb *start_ccb)
515 {
516         struct pass_softc *softc;
517
518         softc = (struct pass_softc *)periph->softc;
519
520         switch (softc->state) {
521         case PASS_STATE_NORMAL:
522         {
523                 struct buf *bp;
524                 struct bio *bio;
525
526                 crit_enter();
527                 bio = bioq_first(&softc->bio_queue);
528                 if (periph->immediate_priority <= periph->pinfo.priority) {
529                         start_ccb->ccb_h.ccb_type = PASS_CCB_WAITING;                   
530                         SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
531                                           periph_links.sle);
532                         periph->immediate_priority = CAM_PRIORITY_NONE;
533                         crit_exit();
534                         wakeup(&periph->ccb_list);
535                 } else if (bio == NULL) {
536                         crit_exit();
537                         xpt_release_ccb(start_ccb);
538                 } else {
539
540                         bioq_remove(&softc->bio_queue, bio);
541                         bp = bio->bio_buf;
542
543                         devstat_start_transaction(&softc->device_stats);
544
545                         /*
546                          * XXX JGibbs -
547                          * Interpret the contents of the bp as a CCB
548                          * and pass it to a routine shared by our ioctl
549                          * code and passtart.
550                          * For now, just biodone it with EIO so we don't
551                          * hang.
552                          */
553                         bp->b_error = EIO;
554                         bp->b_flags |= B_ERROR;
555                         bp->b_resid = bp->b_bcount;
556                         biodone(bio);
557                         bio = bioq_first(&softc->bio_queue);
558                         crit_exit();
559   
560                         xpt_action(start_ccb);
561
562                 }
563                 if (bio != NULL) {
564                         /* Have more work to do, so ensure we stay scheduled */
565                         xpt_schedule(periph, /* XXX priority */1);
566                 }
567                 break;
568         }
569         }
570 }
571 static void
572 passdone(struct cam_periph *periph, union ccb *done_ccb)
573
574         struct pass_softc *softc;
575         struct ccb_scsiio *csio;
576
577         softc = (struct pass_softc *)periph->softc;
578         csio = &done_ccb->csio;
579         switch (csio->ccb_h.ccb_type) {
580         case PASS_CCB_BUFFER_IO:
581         {
582                 struct bio              *bio;
583                 struct buf              *bp;
584                 cam_status              status;
585                 u_int8_t                scsi_status;
586                 devstat_trans_flags     ds_flags;
587
588                 status = done_ccb->ccb_h.status;
589                 scsi_status = done_ccb->csio.scsi_status;
590                 bio = (struct bio *)done_ccb->ccb_h.ccb_bio;
591                 bp = bio->bio_buf;
592
593                 /* XXX handle errors */
594                 if (!(((status & CAM_STATUS_MASK) == CAM_REQ_CMP)
595                   && (scsi_status == SCSI_STATUS_OK))) {
596                         int error;
597                         
598                         if ((error = passerror(done_ccb, 0, 0)) == ERESTART) {
599                                 /*
600                                  * A retry was scheuled, so
601                                  * just return.
602                                  */
603                                 return;
604                         }
605
606                         /*
607                          * XXX unfreeze the queue after we complete
608                          * the abort process
609                          */
610                         bp->b_error = error;
611                         bp->b_flags |= B_ERROR;
612                 }
613
614                 if ((done_ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_IN)
615                         ds_flags = DEVSTAT_READ;
616                 else if ((done_ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_OUT)
617                         ds_flags = DEVSTAT_WRITE;
618                 else
619                         ds_flags = DEVSTAT_NO_DATA;
620
621                 devstat_end_transaction_buf(&softc->device_stats, bp);
622                 biodone(bio);
623                 break;
624         }
625         case PASS_CCB_WAITING:
626         {
627                 /* Caller will release the CCB */
628                 wakeup(&done_ccb->ccb_h.cbfcnp);
629                 return;
630         }
631         }
632         xpt_release_ccb(done_ccb);
633 }
634
635 static int
636 passioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
637 {
638         struct  cam_periph *periph;
639         struct  pass_softc *softc;
640         u_int8_t unit;
641         int      error;
642
643
644         /* unit = dkunit(dev); */
645         /* XXX KDM fix this */
646         unit = minor(dev) & 0xff;
647
648         periph = cam_extend_get(passperiphs, unit);
649
650         if (periph == NULL)
651                 return(ENXIO);
652
653         softc = (struct pass_softc *)periph->softc;
654
655         error = 0;
656
657         switch (cmd) {
658
659         case CAMIOCOMMAND:
660         {
661                 union ccb *inccb;
662                 union ccb *ccb;
663                 int ccb_malloced;
664
665                 inccb = (union ccb *)addr;
666
667                 /*
668                  * Some CCB types, like scan bus and scan lun can only go
669                  * through the transport layer device.
670                  */
671                 if (inccb->ccb_h.func_code & XPT_FC_XPT_ONLY) {
672                         xpt_print_path(periph->path);
673                         printf("CCB function code %#x is restricted to the "
674                                "XPT device\n", inccb->ccb_h.func_code);
675                         error = ENODEV;
676                         break;
677                 }
678
679                 /*
680                  * Non-immediate CCBs need a CCB from the per-device pool
681                  * of CCBs, which is scheduled by the transport layer.
682                  * Immediate CCBs and user-supplied CCBs should just be
683                  * malloced.
684                  */
685                 if ((inccb->ccb_h.func_code & XPT_FC_QUEUED)
686                  && ((inccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0)) {
687                         ccb = cam_periph_getccb(periph,
688                                                 inccb->ccb_h.pinfo.priority);
689                         ccb_malloced = 0;
690                 } else {
691                         ccb = xpt_alloc_ccb();
692
693                         if (ccb != NULL)
694                                 xpt_setup_ccb(&ccb->ccb_h, periph->path,
695                                               inccb->ccb_h.pinfo.priority);
696                         ccb_malloced = 1;
697                 }
698
699                 if (ccb == NULL) {
700                         xpt_print_path(periph->path);
701                         printf("unable to allocate CCB\n");
702                         error = ENOMEM;
703                         break;
704                 }
705
706                 error = passsendccb(periph, ccb, inccb);
707
708                 if (ccb_malloced)
709                         xpt_free_ccb(ccb);
710                 else
711                         xpt_release_ccb(ccb);
712
713                 break;
714         }
715         default:
716                 error = cam_periph_ioctl(periph, cmd, addr, passerror);
717                 break;
718         }
719
720         return(error);
721 }
722
723 /*
724  * Generally, "ccb" should be the CCB supplied by the kernel.  "inccb"
725  * should be the CCB that is copied in from the user.
726  */
727 static int
728 passsendccb(struct cam_periph *periph, union ccb *ccb, union ccb *inccb)
729 {
730         struct pass_softc *softc;
731         struct cam_periph_map_info mapinfo;
732         int error, need_unmap;
733
734         softc = (struct pass_softc *)periph->softc;
735
736         need_unmap = 0;
737
738         /*
739          * There are some fields in the CCB header that need to be
740          * preserved, the rest we get from the user.
741          */
742         xpt_merge_ccb(ccb, inccb);
743
744         /*
745          * There's no way for the user to have a completion
746          * function, so we put our own completion function in here.
747          */
748         ccb->ccb_h.cbfcnp = passdone;
749
750         /*
751          * We only attempt to map the user memory into kernel space
752          * if they haven't passed in a physical memory pointer,
753          * and if there is actually an I/O operation to perform.
754          * Right now cam_periph_mapmem() only supports SCSI and device
755          * match CCBs.  For the SCSI CCBs, we only pass the CCB in if
756          * there's actually data to map.  cam_periph_mapmem() will do the
757          * right thing, even if there isn't data to map, but since CCBs
758          * without data are a reasonably common occurance (e.g. test unit
759          * ready), it will save a few cycles if we check for it here.
760          */
761         if (((ccb->ccb_h.flags & CAM_DATA_PHYS) == 0)
762          && (((ccb->ccb_h.func_code == XPT_SCSI_IO)
763             && ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE))
764           || (ccb->ccb_h.func_code == XPT_DEV_MATCH))) {
765
766                 bzero(&mapinfo, sizeof(mapinfo));
767
768                 error = cam_periph_mapmem(ccb, &mapinfo); 
769
770                 /*
771                  * cam_periph_mapmem returned an error, we can't continue.
772                  * Return the error to the user.
773                  */
774                 if (error)
775                         return(error);
776
777                 /*
778                  * We successfully mapped the memory in, so we need to
779                  * unmap it when the transaction is done.
780                  */
781                 need_unmap = 1;
782         }
783
784         /*
785          * If the user wants us to perform any error recovery, then honor
786          * that request.  Otherwise, it's up to the user to perform any
787          * error recovery.
788          */
789         error = cam_periph_runccb(ccb,
790                                   (ccb->ccb_h.flags & CAM_PASS_ERR_RECOVER) ?
791                                   passerror : NULL,
792                                   /* cam_flags */ 0,
793                                   /* sense_flags */SF_RETRY_UA | SF_RETRY_SELTO,
794                                   &softc->device_stats);
795
796         if (need_unmap != 0)
797                 cam_periph_unmapmem(ccb, &mapinfo);
798
799         ccb->ccb_h.cbfcnp = NULL;
800         ccb->ccb_h.periph_priv = inccb->ccb_h.periph_priv;
801         bcopy(ccb, inccb, sizeof(union ccb));
802
803         return(error);
804 }
805
806 static int
807 passerror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
808 {
809         struct cam_periph *periph;
810         struct pass_softc *softc;
811
812         periph = xpt_path_periph(ccb->ccb_h.path);
813         softc = (struct pass_softc *)periph->softc;
814         
815         return(cam_periph_error(ccb, cam_flags, sense_flags, 
816                                  &softc->saved_ccb));
817 }