scsi: lpfc: Fix crash when cpu count is 1 and null irq affinity mask
[sfrench/cifs-2.6.git] / drivers / s390 / char / tape_core.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    basic function of the tape device driver
4  *
5  *  S390 and zSeries version
6  *    Copyright IBM Corp. 2001, 2009
7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
8  *               Michael Holzheu <holzheu@de.ibm.com>
9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
11  *               Stefan Bader <shbader@de.ibm.com>
12  */
13
14 #define KMSG_COMPONENT "tape"
15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
16
17 #include <linux/module.h>
18 #include <linux/init.h>      // for kernel parameters
19 #include <linux/kmod.h>      // for requesting modules
20 #include <linux/spinlock.h>  // for locks
21 #include <linux/vmalloc.h>
22 #include <linux/list.h>
23 #include <linux/slab.h>
24
25 #include <asm/types.h>       // for variable types
26
27 #define TAPE_DBF_AREA   tape_core_dbf
28
29 #include "tape.h"
30 #include "tape_std.h"
31
32 #define LONG_BUSY_TIMEOUT 180 /* seconds */
33
34 static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
35 static void tape_delayed_next_request(struct work_struct *);
36 static void tape_long_busy_timeout(struct timer_list *t);
37
38 /*
39  * One list to contain all tape devices of all disciplines, so
40  * we can assign the devices to minor numbers of the same major
41  * The list is protected by the rwlock
42  */
43 static LIST_HEAD(tape_device_list);
44 static DEFINE_RWLOCK(tape_device_lock);
45
46 /*
47  * Pointer to debug area.
48  */
49 debug_info_t *TAPE_DBF_AREA = NULL;
50 EXPORT_SYMBOL(TAPE_DBF_AREA);
51
52 /*
53  * Printable strings for tape enumerations.
54  */
55 const char *tape_state_verbose[TS_SIZE] =
56 {
57         [TS_UNUSED]   = "UNUSED",
58         [TS_IN_USE]   = "IN_USE",
59         [TS_BLKUSE]   = "BLKUSE",
60         [TS_INIT]     = "INIT  ",
61         [TS_NOT_OPER] = "NOT_OP"
62 };
63
64 const char *tape_op_verbose[TO_SIZE] =
65 {
66         [TO_BLOCK] = "BLK",     [TO_BSB] = "BSB",
67         [TO_BSF] = "BSF",       [TO_DSE] = "DSE",
68         [TO_FSB] = "FSB",       [TO_FSF] = "FSF",
69         [TO_LBL] = "LBL",       [TO_NOP] = "NOP",
70         [TO_RBA] = "RBA",       [TO_RBI] = "RBI",
71         [TO_RFO] = "RFO",       [TO_REW] = "REW",
72         [TO_RUN] = "RUN",       [TO_WRI] = "WRI",
73         [TO_WTM] = "WTM",       [TO_MSEN] = "MSN",
74         [TO_LOAD] = "LOA",      [TO_READ_CONFIG] = "RCF",
75         [TO_READ_ATTMSG] = "RAT",
76         [TO_DIS] = "DIS",       [TO_ASSIGN] = "ASS",
77         [TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
78         [TO_CRYPT_OFF] = "COF", [TO_KEKL_SET] = "KLS",
79         [TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
80 };
81
82 static int devid_to_int(struct ccw_dev_id *dev_id)
83 {
84         return dev_id->devno + (dev_id->ssid << 16);
85 }
86
87 /*
88  * Some channel attached tape specific attributes.
89  *
90  * FIXME: In the future the first_minor and blocksize attribute should be
91  *        replaced by a link to the cdev tree.
92  */
93 static ssize_t
94 tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
95 {
96         struct tape_device *tdev;
97
98         tdev = dev_get_drvdata(dev);
99         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
100 }
101
102 static
103 DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
104
105 static ssize_t
106 tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
107 {
108         struct tape_device *tdev;
109
110         tdev = dev_get_drvdata(dev);
111         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
112 }
113
114 static
115 DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
116
117 static ssize_t
118 tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
119 {
120         struct tape_device *tdev;
121
122         tdev = dev_get_drvdata(dev);
123         return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
124                 "OFFLINE" : tape_state_verbose[tdev->tape_state]);
125 }
126
127 static
128 DEVICE_ATTR(state, 0444, tape_state_show, NULL);
129
130 static ssize_t
131 tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
132 {
133         struct tape_device *tdev;
134         ssize_t rc;
135
136         tdev = dev_get_drvdata(dev);
137         if (tdev->first_minor < 0)
138                 return scnprintf(buf, PAGE_SIZE, "N/A\n");
139
140         spin_lock_irq(get_ccwdev_lock(tdev->cdev));
141         if (list_empty(&tdev->req_queue))
142                 rc = scnprintf(buf, PAGE_SIZE, "---\n");
143         else {
144                 struct tape_request *req;
145
146                 req = list_entry(tdev->req_queue.next, struct tape_request,
147                         list);
148                 rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
149         }
150         spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
151         return rc;
152 }
153
154 static
155 DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
156
157 static ssize_t
158 tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
159 {
160         struct tape_device *tdev;
161
162         tdev = dev_get_drvdata(dev);
163
164         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
165 }
166
167 static
168 DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
169
170 static struct attribute *tape_attrs[] = {
171         &dev_attr_medium_state.attr,
172         &dev_attr_first_minor.attr,
173         &dev_attr_state.attr,
174         &dev_attr_operation.attr,
175         &dev_attr_blocksize.attr,
176         NULL
177 };
178
179 static const struct attribute_group tape_attr_group = {
180         .attrs = tape_attrs,
181 };
182
183 /*
184  * Tape state functions
185  */
186 void
187 tape_state_set(struct tape_device *device, enum tape_state newstate)
188 {
189         const char *str;
190
191         if (device->tape_state == TS_NOT_OPER) {
192                 DBF_EVENT(3, "ts_set err: not oper\n");
193                 return;
194         }
195         DBF_EVENT(4, "ts. dev:  %x\n", device->first_minor);
196         DBF_EVENT(4, "old ts:\t\n");
197         if (device->tape_state < TS_SIZE && device->tape_state >=0 )
198                 str = tape_state_verbose[device->tape_state];
199         else
200                 str = "UNKNOWN TS";
201         DBF_EVENT(4, "%s\n", str);
202         DBF_EVENT(4, "new ts:\t\n");
203         if (newstate < TS_SIZE && newstate >= 0)
204                 str = tape_state_verbose[newstate];
205         else
206                 str = "UNKNOWN TS";
207         DBF_EVENT(4, "%s\n", str);
208         device->tape_state = newstate;
209         wake_up(&device->state_change_wq);
210 }
211
212 struct tape_med_state_work_data {
213         struct tape_device *device;
214         enum tape_medium_state state;
215         struct work_struct  work;
216 };
217
218 static void
219 tape_med_state_work_handler(struct work_struct *work)
220 {
221         static char env_state_loaded[] = "MEDIUM_STATE=LOADED";
222         static char env_state_unloaded[] = "MEDIUM_STATE=UNLOADED";
223         struct tape_med_state_work_data *p =
224                 container_of(work, struct tape_med_state_work_data, work);
225         struct tape_device *device = p->device;
226         char *envp[] = { NULL, NULL };
227
228         switch (p->state) {
229         case MS_UNLOADED:
230                 pr_info("%s: The tape cartridge has been successfully "
231                         "unloaded\n", dev_name(&device->cdev->dev));
232                 envp[0] = env_state_unloaded;
233                 kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
234                 break;
235         case MS_LOADED:
236                 pr_info("%s: A tape cartridge has been mounted\n",
237                         dev_name(&device->cdev->dev));
238                 envp[0] = env_state_loaded;
239                 kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
240                 break;
241         default:
242                 break;
243         }
244         tape_put_device(device);
245         kfree(p);
246 }
247
248 static void
249 tape_med_state_work(struct tape_device *device, enum tape_medium_state state)
250 {
251         struct tape_med_state_work_data *p;
252
253         p = kzalloc(sizeof(*p), GFP_ATOMIC);
254         if (p) {
255                 INIT_WORK(&p->work, tape_med_state_work_handler);
256                 p->device = tape_get_device(device);
257                 p->state = state;
258                 schedule_work(&p->work);
259         }
260 }
261
262 void
263 tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
264 {
265         enum tape_medium_state oldstate;
266
267         oldstate = device->medium_state;
268         if (oldstate == newstate)
269                 return;
270         device->medium_state = newstate;
271         switch(newstate){
272         case MS_UNLOADED:
273                 device->tape_generic_status |= GMT_DR_OPEN(~0);
274                 if (oldstate == MS_LOADED)
275                         tape_med_state_work(device, MS_UNLOADED);
276                 break;
277         case MS_LOADED:
278                 device->tape_generic_status &= ~GMT_DR_OPEN(~0);
279                 if (oldstate == MS_UNLOADED)
280                         tape_med_state_work(device, MS_LOADED);
281                 break;
282         default:
283                 break;
284         }
285         wake_up(&device->state_change_wq);
286 }
287
288 /*
289  * Stop running ccw. Has to be called with the device lock held.
290  */
291 static int
292 __tape_cancel_io(struct tape_device *device, struct tape_request *request)
293 {
294         int retries;
295         int rc;
296
297         /* Check if interrupt has already been processed */
298         if (request->callback == NULL)
299                 return 0;
300
301         rc = 0;
302         for (retries = 0; retries < 5; retries++) {
303                 rc = ccw_device_clear(device->cdev, (long) request);
304
305                 switch (rc) {
306                         case 0:
307                                 request->status = TAPE_REQUEST_DONE;
308                                 return 0;
309                         case -EBUSY:
310                                 request->status = TAPE_REQUEST_CANCEL;
311                                 schedule_delayed_work(&device->tape_dnr, 0);
312                                 return 0;
313                         case -ENODEV:
314                                 DBF_EXCEPTION(2, "device gone, retry\n");
315                                 break;
316                         case -EIO:
317                                 DBF_EXCEPTION(2, "I/O error, retry\n");
318                                 break;
319                         default:
320                                 BUG();
321                 }
322         }
323
324         return rc;
325 }
326
327 /*
328  * Add device into the sorted list, giving it the first
329  * available minor number.
330  */
331 static int
332 tape_assign_minor(struct tape_device *device)
333 {
334         struct tape_device *tmp;
335         int minor;
336
337         minor = 0;
338         write_lock(&tape_device_lock);
339         list_for_each_entry(tmp, &tape_device_list, node) {
340                 if (minor < tmp->first_minor)
341                         break;
342                 minor += TAPE_MINORS_PER_DEV;
343         }
344         if (minor >= 256) {
345                 write_unlock(&tape_device_lock);
346                 return -ENODEV;
347         }
348         device->first_minor = minor;
349         list_add_tail(&device->node, &tmp->node);
350         write_unlock(&tape_device_lock);
351         return 0;
352 }
353
354 /* remove device from the list */
355 static void
356 tape_remove_minor(struct tape_device *device)
357 {
358         write_lock(&tape_device_lock);
359         list_del_init(&device->node);
360         device->first_minor = -1;
361         write_unlock(&tape_device_lock);
362 }
363
364 /*
365  * Set a device online.
366  *
367  * This function is called by the common I/O layer to move a device from the
368  * detected but offline into the online state.
369  * If we return an error (RC < 0) the device remains in the offline state. This
370  * can happen if the device is assigned somewhere else, for example.
371  */
372 int
373 tape_generic_online(struct tape_device *device,
374                    struct tape_discipline *discipline)
375 {
376         int rc;
377
378         DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
379
380         if (device->tape_state != TS_INIT) {
381                 DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
382                 return -EINVAL;
383         }
384
385         timer_setup(&device->lb_timeout, tape_long_busy_timeout, 0);
386
387         /* Let the discipline have a go at the device. */
388         device->discipline = discipline;
389         if (!try_module_get(discipline->owner)) {
390                 return -EINVAL;
391         }
392
393         rc = discipline->setup_device(device);
394         if (rc)
395                 goto out;
396         rc = tape_assign_minor(device);
397         if (rc)
398                 goto out_discipline;
399
400         rc = tapechar_setup_device(device);
401         if (rc)
402                 goto out_minor;
403
404         tape_state_set(device, TS_UNUSED);
405
406         DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
407
408         return 0;
409
410 out_minor:
411         tape_remove_minor(device);
412 out_discipline:
413         device->discipline->cleanup_device(device);
414         device->discipline = NULL;
415 out:
416         module_put(discipline->owner);
417         return rc;
418 }
419
420 static void
421 tape_cleanup_device(struct tape_device *device)
422 {
423         tapechar_cleanup_device(device);
424         device->discipline->cleanup_device(device);
425         module_put(device->discipline->owner);
426         tape_remove_minor(device);
427         tape_med_state_set(device, MS_UNKNOWN);
428 }
429
430 /*
431  * Suspend device.
432  *
433  * Called by the common I/O layer if the drive should be suspended on user
434  * request. We refuse to suspend if the device is loaded or in use for the
435  * following reason:
436  * While the Linux guest is suspended, it might be logged off which causes
437  * devices to be detached. Tape devices are automatically rewound and unloaded
438  * during DETACH processing (unless the tape device was attached with the
439  * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
440  * resume the original state of the tape device, since we would need to
441  * manually re-load the cartridge which was active at suspend time.
442  */
443 int tape_generic_pm_suspend(struct ccw_device *cdev)
444 {
445         struct tape_device *device;
446
447         device = dev_get_drvdata(&cdev->dev);
448         if (!device) {
449                 return -ENODEV;
450         }
451
452         DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
453                 device->cdev_id, device);
454
455         if (device->medium_state != MS_UNLOADED) {
456                 pr_err("A cartridge is loaded in tape device %s, "
457                        "refusing to suspend\n", dev_name(&cdev->dev));
458                 return -EBUSY;
459         }
460
461         spin_lock_irq(get_ccwdev_lock(device->cdev));
462         switch (device->tape_state) {
463                 case TS_INIT:
464                 case TS_NOT_OPER:
465                 case TS_UNUSED:
466                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
467                         break;
468                 default:
469                         pr_err("Tape device %s is busy, refusing to "
470                                "suspend\n", dev_name(&cdev->dev));
471                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
472                         return -EBUSY;
473         }
474
475         DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
476         return 0;
477 }
478
479 /*
480  * Set device offline.
481  *
482  * Called by the common I/O layer if the drive should set offline on user
483  * request. We may prevent this by returning an error.
484  * Manual offline is only allowed while the drive is not in use.
485  */
486 int
487 tape_generic_offline(struct ccw_device *cdev)
488 {
489         struct tape_device *device;
490
491         device = dev_get_drvdata(&cdev->dev);
492         if (!device) {
493                 return -ENODEV;
494         }
495
496         DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
497                 device->cdev_id, device);
498
499         spin_lock_irq(get_ccwdev_lock(device->cdev));
500         switch (device->tape_state) {
501                 case TS_INIT:
502                 case TS_NOT_OPER:
503                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
504                         break;
505                 case TS_UNUSED:
506                         tape_state_set(device, TS_INIT);
507                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
508                         tape_cleanup_device(device);
509                         break;
510                 default:
511                         DBF_EVENT(3, "(%08x): Set offline failed "
512                                 "- drive in use.\n",
513                                 device->cdev_id);
514                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
515                         return -EBUSY;
516         }
517
518         DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
519         return 0;
520 }
521
522 /*
523  * Allocate memory for a new device structure.
524  */
525 static struct tape_device *
526 tape_alloc_device(void)
527 {
528         struct tape_device *device;
529
530         device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
531         if (device == NULL) {
532                 DBF_EXCEPTION(2, "ti:no mem\n");
533                 return ERR_PTR(-ENOMEM);
534         }
535         device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
536         if (device->modeset_byte == NULL) {
537                 DBF_EXCEPTION(2, "ti:no mem\n");
538                 kfree(device);
539                 return ERR_PTR(-ENOMEM);
540         }
541         mutex_init(&device->mutex);
542         INIT_LIST_HEAD(&device->req_queue);
543         INIT_LIST_HEAD(&device->node);
544         init_waitqueue_head(&device->state_change_wq);
545         init_waitqueue_head(&device->wait_queue);
546         device->tape_state = TS_INIT;
547         device->medium_state = MS_UNKNOWN;
548         *device->modeset_byte = 0;
549         device->first_minor = -1;
550         atomic_set(&device->ref_count, 1);
551         INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);
552
553         return device;
554 }
555
556 /*
557  * Get a reference to an existing device structure. This will automatically
558  * increment the reference count.
559  */
560 struct tape_device *
561 tape_get_device(struct tape_device *device)
562 {
563         int count;
564
565         count = atomic_inc_return(&device->ref_count);
566         DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
567         return device;
568 }
569
570 /*
571  * Decrease the reference counter of a devices structure. If the
572  * reference counter reaches zero free the device structure.
573  * The function returns a NULL pointer to be used by the caller
574  * for clearing reference pointers.
575  */
576 void
577 tape_put_device(struct tape_device *device)
578 {
579         int count;
580
581         count = atomic_dec_return(&device->ref_count);
582         DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
583         BUG_ON(count < 0);
584         if (count == 0) {
585                 kfree(device->modeset_byte);
586                 kfree(device);
587         }
588 }
589
590 /*
591  * Find tape device by a device index.
592  */
593 struct tape_device *
594 tape_find_device(int devindex)
595 {
596         struct tape_device *device, *tmp;
597
598         device = ERR_PTR(-ENODEV);
599         read_lock(&tape_device_lock);
600         list_for_each_entry(tmp, &tape_device_list, node) {
601                 if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
602                         device = tape_get_device(tmp);
603                         break;
604                 }
605         }
606         read_unlock(&tape_device_lock);
607         return device;
608 }
609
610 /*
611  * Driverfs tape probe function.
612  */
613 int
614 tape_generic_probe(struct ccw_device *cdev)
615 {
616         struct tape_device *device;
617         int ret;
618         struct ccw_dev_id dev_id;
619
620         device = tape_alloc_device();
621         if (IS_ERR(device))
622                 return -ENODEV;
623         ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
624                                      CCWDEV_DO_MULTIPATH);
625         ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
626         if (ret) {
627                 tape_put_device(device);
628                 return ret;
629         }
630         dev_set_drvdata(&cdev->dev, device);
631         cdev->handler = __tape_do_irq;
632         device->cdev = cdev;
633         ccw_device_get_id(cdev, &dev_id);
634         device->cdev_id = devid_to_int(&dev_id);
635         return ret;
636 }
637
638 static void
639 __tape_discard_requests(struct tape_device *device)
640 {
641         struct tape_request *   request;
642         struct list_head *      l, *n;
643
644         list_for_each_safe(l, n, &device->req_queue) {
645                 request = list_entry(l, struct tape_request, list);
646                 if (request->status == TAPE_REQUEST_IN_IO)
647                         request->status = TAPE_REQUEST_DONE;
648                 list_del(&request->list);
649
650                 /* Decrease ref_count for removed request. */
651                 request->device = NULL;
652                 tape_put_device(device);
653                 request->rc = -EIO;
654                 if (request->callback != NULL)
655                         request->callback(request, request->callback_data);
656         }
657 }
658
659 /*
660  * Driverfs tape remove function.
661  *
662  * This function is called whenever the common I/O layer detects the device
663  * gone. This can happen at any time and we cannot refuse.
664  */
665 void
666 tape_generic_remove(struct ccw_device *cdev)
667 {
668         struct tape_device *    device;
669
670         device = dev_get_drvdata(&cdev->dev);
671         if (!device) {
672                 return;
673         }
674         DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
675
676         spin_lock_irq(get_ccwdev_lock(device->cdev));
677         switch (device->tape_state) {
678                 case TS_INIT:
679                         tape_state_set(device, TS_NOT_OPER);
680                 case TS_NOT_OPER:
681                         /*
682                          * Nothing to do.
683                          */
684                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
685                         break;
686                 case TS_UNUSED:
687                         /*
688                          * Need only to release the device.
689                          */
690                         tape_state_set(device, TS_NOT_OPER);
691                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
692                         tape_cleanup_device(device);
693                         break;
694                 default:
695                         /*
696                          * There may be requests on the queue. We will not get
697                          * an interrupt for a request that was running. So we
698                          * just post them all as I/O errors.
699                          */
700                         DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
701                                 device->cdev_id);
702                         pr_warn("%s: A tape unit was detached while in use\n",
703                                 dev_name(&device->cdev->dev));
704                         tape_state_set(device, TS_NOT_OPER);
705                         __tape_discard_requests(device);
706                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
707                         tape_cleanup_device(device);
708         }
709
710         device = dev_get_drvdata(&cdev->dev);
711         if (device) {
712                 sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
713                 dev_set_drvdata(&cdev->dev, NULL);
714                 tape_put_device(device);
715         }
716 }
717
718 /*
719  * Allocate a new tape ccw request
720  */
721 struct tape_request *
722 tape_alloc_request(int cplength, int datasize)
723 {
724         struct tape_request *request;
725
726         BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
727
728         DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
729
730         request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
731         if (request == NULL) {
732                 DBF_EXCEPTION(1, "cqra nomem\n");
733                 return ERR_PTR(-ENOMEM);
734         }
735         /* allocate channel program */
736         if (cplength > 0) {
737                 request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
738                                           GFP_ATOMIC | GFP_DMA);
739                 if (request->cpaddr == NULL) {
740                         DBF_EXCEPTION(1, "cqra nomem\n");
741                         kfree(request);
742                         return ERR_PTR(-ENOMEM);
743                 }
744         }
745         /* alloc small kernel buffer */
746         if (datasize > 0) {
747                 request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
748                 if (request->cpdata == NULL) {
749                         DBF_EXCEPTION(1, "cqra nomem\n");
750                         kfree(request->cpaddr);
751                         kfree(request);
752                         return ERR_PTR(-ENOMEM);
753                 }
754         }
755         DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
756                 request->cpdata);
757
758         return request;
759 }
760
761 /*
762  * Free tape ccw request
763  */
764 void
765 tape_free_request (struct tape_request * request)
766 {
767         DBF_LH(6, "Free request %p\n", request);
768
769         if (request->device)
770                 tape_put_device(request->device);
771         kfree(request->cpdata);
772         kfree(request->cpaddr);
773         kfree(request);
774 }
775
776 static int
777 __tape_start_io(struct tape_device *device, struct tape_request *request)
778 {
779         int rc;
780
781         rc = ccw_device_start(
782                 device->cdev,
783                 request->cpaddr,
784                 (unsigned long) request,
785                 0x00,
786                 request->options
787         );
788         if (rc == 0) {
789                 request->status = TAPE_REQUEST_IN_IO;
790         } else if (rc == -EBUSY) {
791                 /* The common I/O subsystem is currently busy. Retry later. */
792                 request->status = TAPE_REQUEST_QUEUED;
793                 schedule_delayed_work(&device->tape_dnr, 0);
794                 rc = 0;
795         } else {
796                 /* Start failed. Remove request and indicate failure. */
797                 DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
798         }
799         return rc;
800 }
801
802 static void
803 __tape_start_next_request(struct tape_device *device)
804 {
805         struct list_head *l, *n;
806         struct tape_request *request;
807         int rc;
808
809         DBF_LH(6, "__tape_start_next_request(%p)\n", device);
810         /*
811          * Try to start each request on request queue until one is
812          * started successful.
813          */
814         list_for_each_safe(l, n, &device->req_queue) {
815                 request = list_entry(l, struct tape_request, list);
816
817                 /*
818                  * Avoid race condition if bottom-half was triggered more than
819                  * once.
820                  */
821                 if (request->status == TAPE_REQUEST_IN_IO)
822                         return;
823                 /*
824                  * Request has already been stopped. We have to wait until
825                  * the request is removed from the queue in the interrupt
826                  * handling.
827                  */
828                 if (request->status == TAPE_REQUEST_DONE)
829                         return;
830
831                 /*
832                  * We wanted to cancel the request but the common I/O layer
833                  * was busy at that time. This can only happen if this
834                  * function is called by delayed_next_request.
835                  * Otherwise we start the next request on the queue.
836                  */
837                 if (request->status == TAPE_REQUEST_CANCEL) {
838                         rc = __tape_cancel_io(device, request);
839                 } else {
840                         rc = __tape_start_io(device, request);
841                 }
842                 if (rc == 0)
843                         return;
844
845                 /* Set ending status. */
846                 request->rc = rc;
847                 request->status = TAPE_REQUEST_DONE;
848
849                 /* Remove from request queue. */
850                 list_del(&request->list);
851
852                 /* Do callback. */
853                 if (request->callback != NULL)
854                         request->callback(request, request->callback_data);
855         }
856 }
857
858 static void
859 tape_delayed_next_request(struct work_struct *work)
860 {
861         struct tape_device *device =
862                 container_of(work, struct tape_device, tape_dnr.work);
863
864         DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
865         spin_lock_irq(get_ccwdev_lock(device->cdev));
866         __tape_start_next_request(device);
867         spin_unlock_irq(get_ccwdev_lock(device->cdev));
868 }
869
870 static void tape_long_busy_timeout(struct timer_list *t)
871 {
872         struct tape_device *device = from_timer(device, t, lb_timeout);
873         struct tape_request *request;
874
875         spin_lock_irq(get_ccwdev_lock(device->cdev));
876         request = list_entry(device->req_queue.next, struct tape_request, list);
877         BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
878         DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
879         __tape_start_next_request(device);
880         tape_put_device(device);
881         spin_unlock_irq(get_ccwdev_lock(device->cdev));
882 }
883
884 static void
885 __tape_end_request(
886         struct tape_device *    device,
887         struct tape_request *   request,
888         int                     rc)
889 {
890         DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
891         if (request) {
892                 request->rc = rc;
893                 request->status = TAPE_REQUEST_DONE;
894
895                 /* Remove from request queue. */
896                 list_del(&request->list);
897
898                 /* Do callback. */
899                 if (request->callback != NULL)
900                         request->callback(request, request->callback_data);
901         }
902
903         /* Start next request. */
904         if (!list_empty(&device->req_queue))
905                 __tape_start_next_request(device);
906 }
907
908 /*
909  * Write sense data to dbf
910  */
911 void
912 tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
913                     struct irb *irb)
914 {
915         unsigned int *sptr;
916         const char* op;
917
918         if (request != NULL)
919                 op = tape_op_verbose[request->op];
920         else
921                 op = "---";
922         DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
923                   irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
924         DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
925         sptr = (unsigned int *) irb->ecw;
926         DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
927         DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
928         DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
929         DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
930 }
931
932 /*
933  * I/O helper function. Adds the request to the request queue
934  * and starts it if the tape is idle. Has to be called with
935  * the device lock held.
936  */
937 static int
938 __tape_start_request(struct tape_device *device, struct tape_request *request)
939 {
940         int rc;
941
942         switch (request->op) {
943                 case TO_MSEN:
944                 case TO_ASSIGN:
945                 case TO_UNASSIGN:
946                 case TO_READ_ATTMSG:
947                 case TO_RDC:
948                         if (device->tape_state == TS_INIT)
949                                 break;
950                         if (device->tape_state == TS_UNUSED)
951                                 break;
952                 default:
953                         if (device->tape_state == TS_BLKUSE)
954                                 break;
955                         if (device->tape_state != TS_IN_USE)
956                                 return -ENODEV;
957         }
958
959         /* Increase use count of device for the added request. */
960         request->device = tape_get_device(device);
961
962         if (list_empty(&device->req_queue)) {
963                 /* No other requests are on the queue. Start this one. */
964                 rc = __tape_start_io(device, request);
965                 if (rc)
966                         return rc;
967
968                 DBF_LH(5, "Request %p added for execution.\n", request);
969                 list_add(&request->list, &device->req_queue);
970         } else {
971                 DBF_LH(5, "Request %p add to queue.\n", request);
972                 request->status = TAPE_REQUEST_QUEUED;
973                 list_add_tail(&request->list, &device->req_queue);
974         }
975         return 0;
976 }
977
978 /*
979  * Add the request to the request queue, try to start it if the
980  * tape is idle. Return without waiting for end of i/o.
981  */
982 int
983 tape_do_io_async(struct tape_device *device, struct tape_request *request)
984 {
985         int rc;
986
987         DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
988
989         spin_lock_irq(get_ccwdev_lock(device->cdev));
990         /* Add request to request queue and try to start it. */
991         rc = __tape_start_request(device, request);
992         spin_unlock_irq(get_ccwdev_lock(device->cdev));
993         return rc;
994 }
995
996 /*
997  * tape_do_io/__tape_wake_up
998  * Add the request to the request queue, try to start it if the
999  * tape is idle and wait uninterruptible for its completion.
1000  */
1001 static void
1002 __tape_wake_up(struct tape_request *request, void *data)
1003 {
1004         request->callback = NULL;
1005         wake_up((wait_queue_head_t *) data);
1006 }
1007
1008 int
1009 tape_do_io(struct tape_device *device, struct tape_request *request)
1010 {
1011         int rc;
1012
1013         spin_lock_irq(get_ccwdev_lock(device->cdev));
1014         /* Setup callback */
1015         request->callback = __tape_wake_up;
1016         request->callback_data = &device->wait_queue;
1017         /* Add request to request queue and try to start it. */
1018         rc = __tape_start_request(device, request);
1019         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1020         if (rc)
1021                 return rc;
1022         /* Request added to the queue. Wait for its completion. */
1023         wait_event(device->wait_queue, (request->callback == NULL));
1024         /* Get rc from request */
1025         return request->rc;
1026 }
1027
1028 /*
1029  * tape_do_io_interruptible/__tape_wake_up_interruptible
1030  * Add the request to the request queue, try to start it if the
1031  * tape is idle and wait uninterruptible for its completion.
1032  */
1033 static void
1034 __tape_wake_up_interruptible(struct tape_request *request, void *data)
1035 {
1036         request->callback = NULL;
1037         wake_up_interruptible((wait_queue_head_t *) data);
1038 }
1039
1040 int
1041 tape_do_io_interruptible(struct tape_device *device,
1042                          struct tape_request *request)
1043 {
1044         int rc;
1045
1046         spin_lock_irq(get_ccwdev_lock(device->cdev));
1047         /* Setup callback */
1048         request->callback = __tape_wake_up_interruptible;
1049         request->callback_data = &device->wait_queue;
1050         rc = __tape_start_request(device, request);
1051         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1052         if (rc)
1053                 return rc;
1054         /* Request added to the queue. Wait for its completion. */
1055         rc = wait_event_interruptible(device->wait_queue,
1056                                       (request->callback == NULL));
1057         if (rc != -ERESTARTSYS)
1058                 /* Request finished normally. */
1059                 return request->rc;
1060
1061         /* Interrupted by a signal. We have to stop the current request. */
1062         spin_lock_irq(get_ccwdev_lock(device->cdev));
1063         rc = __tape_cancel_io(device, request);
1064         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1065         if (rc == 0) {
1066                 /* Wait for the interrupt that acknowledges the halt. */
1067                 do {
1068                         rc = wait_event_interruptible(
1069                                 device->wait_queue,
1070                                 (request->callback == NULL)
1071                         );
1072                 } while (rc == -ERESTARTSYS);
1073
1074                 DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
1075                 rc = -ERESTARTSYS;
1076         }
1077         return rc;
1078 }
1079
1080 /*
1081  * Stop running ccw.
1082  */
1083 int
1084 tape_cancel_io(struct tape_device *device, struct tape_request *request)
1085 {
1086         int rc;
1087
1088         spin_lock_irq(get_ccwdev_lock(device->cdev));
1089         rc = __tape_cancel_io(device, request);
1090         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1091         return rc;
1092 }
1093
1094 /*
1095  * Tape interrupt routine, called from the ccw_device layer
1096  */
1097 static void
1098 __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1099 {
1100         struct tape_device *device;
1101         struct tape_request *request;
1102         int rc;
1103
1104         device = dev_get_drvdata(&cdev->dev);
1105         if (device == NULL) {
1106                 return;
1107         }
1108         request = (struct tape_request *) intparm;
1109
1110         DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1111
1112         /* On special conditions irb is an error pointer */
1113         if (IS_ERR(irb)) {
1114                 /* FIXME: What to do with the request? */
1115                 switch (PTR_ERR(irb)) {
1116                         case -ETIMEDOUT:
1117                                 DBF_LH(1, "(%08x): Request timed out\n",
1118                                        device->cdev_id);
1119                         case -EIO:
1120                                 __tape_end_request(device, request, -EIO);
1121                                 break;
1122                         default:
1123                                 DBF_LH(1, "(%08x): Unexpected i/o error %li\n",
1124                                        device->cdev_id, PTR_ERR(irb));
1125                 }
1126                 return;
1127         }
1128
1129         /*
1130          * If the condition code is not zero and the start function bit is
1131          * still set, this is an deferred error and the last start I/O did
1132          * not succeed. At this point the condition that caused the deferred
1133          * error might still apply. So we just schedule the request to be
1134          * started later.
1135          */
1136         if (irb->scsw.cmd.cc != 0 &&
1137             (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
1138             (request->status == TAPE_REQUEST_IN_IO)) {
1139                 DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
1140                         device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
1141                 request->status = TAPE_REQUEST_QUEUED;
1142                 schedule_delayed_work(&device->tape_dnr, HZ);
1143                 return;
1144         }
1145
1146         /* May be an unsolicited irq */
1147         if(request != NULL)
1148                 request->rescnt = irb->scsw.cmd.count;
1149         else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
1150                  !list_empty(&device->req_queue)) {
1151                 /* Not Ready to Ready after long busy ? */
1152                 struct tape_request *req;
1153                 req = list_entry(device->req_queue.next,
1154                                  struct tape_request, list);
1155                 if (req->status == TAPE_REQUEST_LONG_BUSY) {
1156                         DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
1157                         if (del_timer(&device->lb_timeout)) {
1158                                 tape_put_device(device);
1159                                 __tape_start_next_request(device);
1160                         }
1161                         return;
1162                 }
1163         }
1164         if (irb->scsw.cmd.dstat != 0x0c) {
1165                 /* Set the 'ONLINE' flag depending on sense byte 1 */
1166                 if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1167                         device->tape_generic_status |= GMT_ONLINE(~0);
1168                 else
1169                         device->tape_generic_status &= ~GMT_ONLINE(~0);
1170
1171                 /*
1172                  * Any request that does not come back with channel end
1173                  * and device end is unusual. Log the sense data.
1174                  */
1175                 DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1176                 tape_dump_sense_dbf(device, request, irb);
1177         } else {
1178                 /* Upon normal completion the device _is_ online */
1179                 device->tape_generic_status |= GMT_ONLINE(~0);
1180         }
1181         if (device->tape_state == TS_NOT_OPER) {
1182                 DBF_EVENT(6, "tape:device is not operational\n");
1183                 return;
1184         }
1185
1186         /*
1187          * Request that were canceled still come back with an interrupt.
1188          * To detect these request the state will be set to TAPE_REQUEST_DONE.
1189          */
1190         if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1191                 __tape_end_request(device, request, -EIO);
1192                 return;
1193         }
1194
1195         rc = device->discipline->irq(device, request, irb);
1196         /*
1197          * rc < 0 : request finished unsuccessfully.
1198          * rc == TAPE_IO_SUCCESS: request finished successfully.
1199          * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1200          * rc == TAPE_IO_RETRY: request finished but needs another go.
1201          * rc == TAPE_IO_STOP: request needs to get terminated.
1202          */
1203         switch (rc) {
1204                 case TAPE_IO_SUCCESS:
1205                         /* Upon normal completion the device _is_ online */
1206                         device->tape_generic_status |= GMT_ONLINE(~0);
1207                         __tape_end_request(device, request, rc);
1208                         break;
1209                 case TAPE_IO_PENDING:
1210                         break;
1211                 case TAPE_IO_LONG_BUSY:
1212                         device->lb_timeout.expires = jiffies +
1213                                 LONG_BUSY_TIMEOUT * HZ;
1214                         DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
1215                         add_timer(&device->lb_timeout);
1216                         request->status = TAPE_REQUEST_LONG_BUSY;
1217                         break;
1218                 case TAPE_IO_RETRY:
1219                         rc = __tape_start_io(device, request);
1220                         if (rc)
1221                                 __tape_end_request(device, request, rc);
1222                         break;
1223                 case TAPE_IO_STOP:
1224                         rc = __tape_cancel_io(device, request);
1225                         if (rc)
1226                                 __tape_end_request(device, request, rc);
1227                         break;
1228                 default:
1229                         if (rc > 0) {
1230                                 DBF_EVENT(6, "xunknownrc\n");
1231                                 __tape_end_request(device, request, -EIO);
1232                         } else {
1233                                 __tape_end_request(device, request, rc);
1234                         }
1235                         break;
1236         }
1237 }
1238
1239 /*
1240  * Tape device open function used by tape_char frontend.
1241  */
1242 int
1243 tape_open(struct tape_device *device)
1244 {
1245         int rc;
1246
1247         spin_lock_irq(get_ccwdev_lock(device->cdev));
1248         if (device->tape_state == TS_NOT_OPER) {
1249                 DBF_EVENT(6, "TAPE:nodev\n");
1250                 rc = -ENODEV;
1251         } else if (device->tape_state == TS_IN_USE) {
1252                 DBF_EVENT(6, "TAPE:dbusy\n");
1253                 rc = -EBUSY;
1254         } else if (device->tape_state == TS_BLKUSE) {
1255                 DBF_EVENT(6, "TAPE:dbusy\n");
1256                 rc = -EBUSY;
1257         } else if (device->discipline != NULL &&
1258                    !try_module_get(device->discipline->owner)) {
1259                 DBF_EVENT(6, "TAPE:nodisc\n");
1260                 rc = -ENODEV;
1261         } else {
1262                 tape_state_set(device, TS_IN_USE);
1263                 rc = 0;
1264         }
1265         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1266         return rc;
1267 }
1268
1269 /*
1270  * Tape device release function used by tape_char frontend.
1271  */
1272 int
1273 tape_release(struct tape_device *device)
1274 {
1275         spin_lock_irq(get_ccwdev_lock(device->cdev));
1276         if (device->tape_state == TS_IN_USE)
1277                 tape_state_set(device, TS_UNUSED);
1278         module_put(device->discipline->owner);
1279         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1280         return 0;
1281 }
1282
1283 /*
1284  * Execute a magnetic tape command a number of times.
1285  */
1286 int
1287 tape_mtop(struct tape_device *device, int mt_op, int mt_count)
1288 {
1289         tape_mtop_fn fn;
1290         int rc;
1291
1292         DBF_EVENT(6, "TAPE:mtio\n");
1293         DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
1294         DBF_EVENT(6, "TAPE:arg:  %x\n", mt_count);
1295
1296         if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
1297                 return -EINVAL;
1298         fn = device->discipline->mtop_array[mt_op];
1299         if (fn == NULL)
1300                 return -EINVAL;
1301
1302         /* We assume that the backends can handle count up to 500. */
1303         if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
1304             mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
1305                 rc = 0;
1306                 for (; mt_count > 500; mt_count -= 500)
1307                         if ((rc = fn(device, 500)) != 0)
1308                                 break;
1309                 if (rc == 0)
1310                         rc = fn(device, mt_count);
1311         } else
1312                 rc = fn(device, mt_count);
1313         return rc;
1314
1315 }
1316
1317 /*
1318  * Tape init function.
1319  */
1320 static int
1321 tape_init (void)
1322 {
1323         TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
1324         debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
1325 #ifdef DBF_LIKE_HELL
1326         debug_set_level(TAPE_DBF_AREA, 6);
1327 #endif
1328         DBF_EVENT(3, "tape init\n");
1329         tape_proc_init();
1330         tapechar_init ();
1331         return 0;
1332 }
1333
1334 /*
1335  * Tape exit function.
1336  */
1337 static void
1338 tape_exit(void)
1339 {
1340         DBF_EVENT(6, "tape exit\n");
1341
1342         /* Get rid of the frontends */
1343         tapechar_exit();
1344         tape_proc_cleanup();
1345         debug_unregister (TAPE_DBF_AREA);
1346 }
1347
1348 MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
1349               "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
1350 MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
1351 MODULE_LICENSE("GPL");
1352
1353 module_init(tape_init);
1354 module_exit(tape_exit);
1355
1356 EXPORT_SYMBOL(tape_generic_remove);
1357 EXPORT_SYMBOL(tape_generic_probe);
1358 EXPORT_SYMBOL(tape_generic_online);
1359 EXPORT_SYMBOL(tape_generic_offline);
1360 EXPORT_SYMBOL(tape_generic_pm_suspend);
1361 EXPORT_SYMBOL(tape_put_device);
1362 EXPORT_SYMBOL(tape_get_device);
1363 EXPORT_SYMBOL(tape_state_verbose);
1364 EXPORT_SYMBOL(tape_op_verbose);
1365 EXPORT_SYMBOL(tape_state_set);
1366 EXPORT_SYMBOL(tape_med_state_set);
1367 EXPORT_SYMBOL(tape_alloc_request);
1368 EXPORT_SYMBOL(tape_free_request);
1369 EXPORT_SYMBOL(tape_dump_sense_dbf);
1370 EXPORT_SYMBOL(tape_do_io);
1371 EXPORT_SYMBOL(tape_do_io_async);
1372 EXPORT_SYMBOL(tape_do_io_interruptible);
1373 EXPORT_SYMBOL(tape_cancel_io);
1374 EXPORT_SYMBOL(tape_mtop);