fix memory leak in fixed btusb_close
[sfrench/cifs-2.6.git] / drivers / s390 / char / monreader.c
1 /*
2  * Character device driver for reading z/VM *MONITOR service records.
3  *
4  * Copyright IBM Corp. 2004, 2009
5  *
6  * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
7  */
8
9 #define KMSG_COMPONENT "monreader"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/init.h>
15 #include <linux/smp_lock.h>
16 #include <linux/errno.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/miscdevice.h>
20 #include <linux/ctype.h>
21 #include <linux/spinlock.h>
22 #include <linux/interrupt.h>
23 #include <linux/poll.h>
24 #include <linux/device.h>
25 #include <net/iucv/iucv.h>
26 #include <asm/uaccess.h>
27 #include <asm/ebcdic.h>
28 #include <asm/extmem.h>
29
30
31 #define MON_COLLECT_SAMPLE 0x80
32 #define MON_COLLECT_EVENT  0x40
33 #define MON_SERVICE        "*MONITOR"
34 #define MON_IN_USE         0x01
35 #define MON_MSGLIM         255
36
37 static char mon_dcss_name[9] = "MONDCSS\0";
38
39 struct mon_msg {
40         u32 pos;
41         u32 mca_offset;
42         struct iucv_message msg;
43         char msglim_reached;
44         char replied_msglim;
45 };
46
47 struct mon_private {
48         struct iucv_path *path;
49         struct mon_msg *msg_array[MON_MSGLIM];
50         unsigned int   write_index;
51         unsigned int   read_index;
52         atomic_t msglim_count;
53         atomic_t read_ready;
54         atomic_t iucv_connected;
55         atomic_t iucv_severed;
56 };
57
58 static unsigned long mon_in_use = 0;
59
60 static unsigned long mon_dcss_start;
61 static unsigned long mon_dcss_end;
62
63 static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
64 static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
65
66 static u8 user_data_connect[16] = {
67         /* Version code, must be 0x01 for shared mode */
68         0x01,
69         /* what to collect */
70         MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
71         /* DCSS name in EBCDIC, 8 bytes padded with blanks */
72         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
73         0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
74 };
75
76 static u8 user_data_sever[16] = {
77         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
78         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
79 };
80
81 static struct device *monreader_device;
82
83 /******************************************************************************
84  *                             helper functions                               *
85  *****************************************************************************/
86 /*
87  * Create the 8 bytes EBCDIC DCSS segment name from
88  * an ASCII name, incl. padding
89  */
90 static void dcss_mkname(char *ascii_name, char *ebcdic_name)
91 {
92         int i;
93
94         for (i = 0; i < 8; i++) {
95                 if (ascii_name[i] == '\0')
96                         break;
97                 ebcdic_name[i] = toupper(ascii_name[i]);
98         };
99         for (; i < 8; i++)
100                 ebcdic_name[i] = ' ';
101         ASCEBC(ebcdic_name, 8);
102 }
103
104 static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
105 {
106         return *(u32 *) &monmsg->msg.rmmsg;
107 }
108
109 static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
110 {
111         return *(u32 *) &monmsg->msg.rmmsg[4];
112 }
113
114 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
115 {
116         return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
117 }
118
119 static inline u32 mon_mca_size(struct mon_msg *monmsg)
120 {
121         return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
122 }
123
124 static inline u32 mon_rec_start(struct mon_msg *monmsg)
125 {
126         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
127 }
128
129 static inline u32 mon_rec_end(struct mon_msg *monmsg)
130 {
131         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
132 }
133
134 static int mon_check_mca(struct mon_msg *monmsg)
135 {
136         if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
137             (mon_rec_start(monmsg) < mon_dcss_start) ||
138             (mon_rec_end(monmsg) > mon_dcss_end) ||
139             (mon_mca_type(monmsg, 0) == 0) ||
140             (mon_mca_size(monmsg) % 12 != 0) ||
141             (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
142             (mon_mca_end(monmsg) > mon_dcss_end) ||
143             (mon_mca_start(monmsg) < mon_dcss_start) ||
144             ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
145                 return -EINVAL;
146         return 0;
147 }
148
149 static int mon_send_reply(struct mon_msg *monmsg,
150                           struct mon_private *monpriv)
151 {
152         int rc;
153
154         rc = iucv_message_reply(monpriv->path, &monmsg->msg,
155                                 IUCV_IPRMDATA, NULL, 0);
156         atomic_dec(&monpriv->msglim_count);
157         if (likely(!monmsg->msglim_reached)) {
158                 monmsg->pos = 0;
159                 monmsg->mca_offset = 0;
160                 monpriv->read_index = (monpriv->read_index + 1) %
161                                       MON_MSGLIM;
162                 atomic_dec(&monpriv->read_ready);
163         } else
164                 monmsg->replied_msglim = 1;
165         if (rc) {
166                 pr_err("Reading monitor data failed with rc=%i\n", rc);
167                 return -EIO;
168         }
169         return 0;
170 }
171
172 static void mon_free_mem(struct mon_private *monpriv)
173 {
174         int i;
175
176         for (i = 0; i < MON_MSGLIM; i++)
177                 if (monpriv->msg_array[i])
178                         kfree(monpriv->msg_array[i]);
179         kfree(monpriv);
180 }
181
182 static struct mon_private *mon_alloc_mem(void)
183 {
184         int i;
185         struct mon_private *monpriv;
186
187         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
188         if (!monpriv)
189                 return NULL;
190         for (i = 0; i < MON_MSGLIM; i++) {
191                 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
192                                                     GFP_KERNEL);
193                 if (!monpriv->msg_array[i]) {
194                         mon_free_mem(monpriv);
195                         return NULL;
196                 }
197         }
198         return monpriv;
199 }
200
201 static inline void mon_next_mca(struct mon_msg *monmsg)
202 {
203         if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
204                 return;
205         monmsg->mca_offset += 12;
206         monmsg->pos = 0;
207 }
208
209 static struct mon_msg *mon_next_message(struct mon_private *monpriv)
210 {
211         struct mon_msg *monmsg;
212
213         if (!atomic_read(&monpriv->read_ready))
214                 return NULL;
215         monmsg = monpriv->msg_array[monpriv->read_index];
216         if (unlikely(monmsg->replied_msglim)) {
217                 monmsg->replied_msglim = 0;
218                 monmsg->msglim_reached = 0;
219                 monmsg->pos = 0;
220                 monmsg->mca_offset = 0;
221                 monpriv->read_index = (monpriv->read_index + 1) %
222                                       MON_MSGLIM;
223                 atomic_dec(&monpriv->read_ready);
224                 return ERR_PTR(-EOVERFLOW);
225         }
226         return monmsg;
227 }
228
229
230 /******************************************************************************
231  *                               IUCV handler                                 *
232  *****************************************************************************/
233 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
234 {
235         struct mon_private *monpriv = path->private;
236
237         atomic_set(&monpriv->iucv_connected, 1);
238         wake_up(&mon_conn_wait_queue);
239 }
240
241 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
242 {
243         struct mon_private *monpriv = path->private;
244
245         pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
246                ipuser[0]);
247         iucv_path_sever(path, NULL);
248         atomic_set(&monpriv->iucv_severed, 1);
249         wake_up(&mon_conn_wait_queue);
250         wake_up_interruptible(&mon_read_wait_queue);
251 }
252
253 static void mon_iucv_message_pending(struct iucv_path *path,
254                                      struct iucv_message *msg)
255 {
256         struct mon_private *monpriv = path->private;
257
258         memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
259                msg, sizeof(*msg));
260         if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
261                 pr_warning("The read queue for monitor data is full\n");
262                 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
263         }
264         monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
265         atomic_inc(&monpriv->read_ready);
266         wake_up_interruptible(&mon_read_wait_queue);
267 }
268
269 static struct iucv_handler monreader_iucv_handler = {
270         .path_complete   = mon_iucv_path_complete,
271         .path_severed    = mon_iucv_path_severed,
272         .message_pending = mon_iucv_message_pending,
273 };
274
275 /******************************************************************************
276  *                               file operations                              *
277  *****************************************************************************/
278 static int mon_open(struct inode *inode, struct file *filp)
279 {
280         struct mon_private *monpriv;
281         int rc;
282
283         /*
284          * only one user allowed
285          */
286         lock_kernel();
287         rc = -EBUSY;
288         if (test_and_set_bit(MON_IN_USE, &mon_in_use))
289                 goto out;
290
291         rc = -ENOMEM;
292         monpriv = mon_alloc_mem();
293         if (!monpriv)
294                 goto out_use;
295
296         /*
297          * Connect to *MONITOR service
298          */
299         monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
300         if (!monpriv->path)
301                 goto out_priv;
302         rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
303                                MON_SERVICE, NULL, user_data_connect, monpriv);
304         if (rc) {
305                 pr_err("Connecting to the z/VM *MONITOR system service "
306                        "failed with rc=%i\n", rc);
307                 rc = -EIO;
308                 goto out_path;
309         }
310         /*
311          * Wait for connection confirmation
312          */
313         wait_event(mon_conn_wait_queue,
314                    atomic_read(&monpriv->iucv_connected) ||
315                    atomic_read(&monpriv->iucv_severed));
316         if (atomic_read(&monpriv->iucv_severed)) {
317                 atomic_set(&monpriv->iucv_severed, 0);
318                 atomic_set(&monpriv->iucv_connected, 0);
319                 rc = -EIO;
320                 goto out_path;
321         }
322         filp->private_data = monpriv;
323         dev_set_drvdata(monreader_device, monpriv);
324         unlock_kernel();
325         return nonseekable_open(inode, filp);
326
327 out_path:
328         iucv_path_free(monpriv->path);
329 out_priv:
330         mon_free_mem(monpriv);
331 out_use:
332         clear_bit(MON_IN_USE, &mon_in_use);
333 out:
334         unlock_kernel();
335         return rc;
336 }
337
338 static int mon_close(struct inode *inode, struct file *filp)
339 {
340         int rc, i;
341         struct mon_private *monpriv = filp->private_data;
342
343         /*
344          * Close IUCV connection and unregister
345          */
346         if (monpriv->path) {
347                 rc = iucv_path_sever(monpriv->path, user_data_sever);
348                 if (rc)
349                         pr_warning("Disconnecting the z/VM *MONITOR system "
350                                    "service failed with rc=%i\n", rc);
351                 iucv_path_free(monpriv->path);
352         }
353
354         atomic_set(&monpriv->iucv_severed, 0);
355         atomic_set(&monpriv->iucv_connected, 0);
356         atomic_set(&monpriv->read_ready, 0);
357         atomic_set(&monpriv->msglim_count, 0);
358         monpriv->write_index  = 0;
359         monpriv->read_index   = 0;
360
361         for (i = 0; i < MON_MSGLIM; i++)
362                 kfree(monpriv->msg_array[i]);
363         kfree(monpriv);
364         clear_bit(MON_IN_USE, &mon_in_use);
365         return 0;
366 }
367
368 static ssize_t mon_read(struct file *filp, char __user *data,
369                         size_t count, loff_t *ppos)
370 {
371         struct mon_private *monpriv = filp->private_data;
372         struct mon_msg *monmsg;
373         int ret;
374         u32 mce_start;
375
376         monmsg = mon_next_message(monpriv);
377         if (IS_ERR(monmsg))
378                 return PTR_ERR(monmsg);
379
380         if (!monmsg) {
381                 if (filp->f_flags & O_NONBLOCK)
382                         return -EAGAIN;
383                 ret = wait_event_interruptible(mon_read_wait_queue,
384                                         atomic_read(&monpriv->read_ready) ||
385                                         atomic_read(&monpriv->iucv_severed));
386                 if (ret)
387                         return ret;
388                 if (unlikely(atomic_read(&monpriv->iucv_severed)))
389                         return -EIO;
390                 monmsg = monpriv->msg_array[monpriv->read_index];
391         }
392
393         if (!monmsg->pos)
394                 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
395         if (mon_check_mca(monmsg))
396                 goto reply;
397
398         /* read monitor control element (12 bytes) first */
399         mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
400         if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
401                 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
402                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
403                                    count);
404                 if (ret)
405                         return -EFAULT;
406                 monmsg->pos += count;
407                 if (monmsg->pos == mce_start + 12)
408                         monmsg->pos = mon_rec_start(monmsg);
409                 goto out_copy;
410         }
411
412         /* read records */
413         if (monmsg->pos <= mon_rec_end(monmsg)) {
414                 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
415                                             + 1);
416                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
417                                    count);
418                 if (ret)
419                         return -EFAULT;
420                 monmsg->pos += count;
421                 if (monmsg->pos > mon_rec_end(monmsg))
422                         mon_next_mca(monmsg);
423                 goto out_copy;
424         }
425 reply:
426         ret = mon_send_reply(monmsg, monpriv);
427         return ret;
428
429 out_copy:
430         *ppos += count;
431         return count;
432 }
433
434 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
435 {
436         struct mon_private *monpriv = filp->private_data;
437
438         poll_wait(filp, &mon_read_wait_queue, p);
439         if (unlikely(atomic_read(&monpriv->iucv_severed)))
440                 return POLLERR;
441         if (atomic_read(&monpriv->read_ready))
442                 return POLLIN | POLLRDNORM;
443         return 0;
444 }
445
446 static const struct file_operations mon_fops = {
447         .owner   = THIS_MODULE,
448         .open    = &mon_open,
449         .release = &mon_close,
450         .read    = &mon_read,
451         .poll    = &mon_poll,
452 };
453
454 static struct miscdevice mon_dev = {
455         .name       = "monreader",
456         .fops       = &mon_fops,
457         .minor      = MISC_DYNAMIC_MINOR,
458 };
459
460
461 /******************************************************************************
462  *                              suspend / resume                              *
463  *****************************************************************************/
464 static int monreader_freeze(struct device *dev)
465 {
466         struct mon_private *monpriv = dev_get_drvdata(dev);
467         int rc;
468
469         if (!monpriv)
470                 return 0;
471         if (monpriv->path) {
472                 rc = iucv_path_sever(monpriv->path, user_data_sever);
473                 if (rc)
474                         pr_warning("Disconnecting the z/VM *MONITOR system "
475                                    "service failed with rc=%i\n", rc);
476                 iucv_path_free(monpriv->path);
477         }
478         atomic_set(&monpriv->iucv_severed, 0);
479         atomic_set(&monpriv->iucv_connected, 0);
480         atomic_set(&monpriv->read_ready, 0);
481         atomic_set(&monpriv->msglim_count, 0);
482         monpriv->write_index  = 0;
483         monpriv->read_index   = 0;
484         monpriv->path = NULL;
485         return 0;
486 }
487
488 static int monreader_thaw(struct device *dev)
489 {
490         struct mon_private *monpriv = dev_get_drvdata(dev);
491         int rc;
492
493         if (!monpriv)
494                 return 0;
495         rc = -ENOMEM;
496         monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
497         if (!monpriv->path)
498                 goto out;
499         rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
500                                MON_SERVICE, NULL, user_data_connect, monpriv);
501         if (rc) {
502                 pr_err("Connecting to the z/VM *MONITOR system service "
503                        "failed with rc=%i\n", rc);
504                 goto out_path;
505         }
506         wait_event(mon_conn_wait_queue,
507                    atomic_read(&monpriv->iucv_connected) ||
508                    atomic_read(&monpriv->iucv_severed));
509         if (atomic_read(&monpriv->iucv_severed))
510                 goto out_path;
511         return 0;
512 out_path:
513         rc = -EIO;
514         iucv_path_free(monpriv->path);
515         monpriv->path = NULL;
516 out:
517         atomic_set(&monpriv->iucv_severed, 1);
518         return rc;
519 }
520
521 static int monreader_restore(struct device *dev)
522 {
523         int rc;
524
525         segment_unload(mon_dcss_name);
526         rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
527                           &mon_dcss_start, &mon_dcss_end);
528         if (rc < 0) {
529                 segment_warning(rc, mon_dcss_name);
530                 panic("fatal monreader resume error: no monitor dcss\n");
531         }
532         return monreader_thaw(dev);
533 }
534
535 static struct dev_pm_ops monreader_pm_ops = {
536         .freeze  = monreader_freeze,
537         .thaw    = monreader_thaw,
538         .restore = monreader_restore,
539 };
540
541 static struct device_driver monreader_driver = {
542         .name = "monreader",
543         .bus  = &iucv_bus,
544         .pm   = &monreader_pm_ops,
545 };
546
547
548 /******************************************************************************
549  *                              module init/exit                              *
550  *****************************************************************************/
551 static int __init mon_init(void)
552 {
553         int rc;
554
555         if (!MACHINE_IS_VM) {
556                 pr_err("The z/VM *MONITOR record device driver cannot be "
557                        "loaded without z/VM\n");
558                 return -ENODEV;
559         }
560
561         /*
562          * Register with IUCV and connect to *MONITOR service
563          */
564         rc = iucv_register(&monreader_iucv_handler, 1);
565         if (rc) {
566                 pr_err("The z/VM *MONITOR record device driver failed to "
567                        "register with IUCV\n");
568                 return rc;
569         }
570
571         rc = driver_register(&monreader_driver);
572         if (rc)
573                 goto out_iucv;
574         monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
575         if (!monreader_device)
576                 goto out_driver;
577         dev_set_name(monreader_device, "monreader-dev");
578         monreader_device->bus = &iucv_bus;
579         monreader_device->parent = iucv_root;
580         monreader_device->driver = &monreader_driver;
581         monreader_device->release = (void (*)(struct device *))kfree;
582         rc = device_register(monreader_device);
583         if (rc) {
584                 put_device(monreader_device);
585                 goto out_driver;
586         }
587
588         rc = segment_type(mon_dcss_name);
589         if (rc < 0) {
590                 segment_warning(rc, mon_dcss_name);
591                 goto out_device;
592         }
593         if (rc != SEG_TYPE_SC) {
594                 pr_err("The specified *MONITOR DCSS %s does not have the "
595                        "required type SC\n", mon_dcss_name);
596                 rc = -EINVAL;
597                 goto out_device;
598         }
599
600         rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
601                           &mon_dcss_start, &mon_dcss_end);
602         if (rc < 0) {
603                 segment_warning(rc, mon_dcss_name);
604                 rc = -EINVAL;
605                 goto out_device;
606         }
607         dcss_mkname(mon_dcss_name, &user_data_connect[8]);
608
609         rc = misc_register(&mon_dev);
610         if (rc < 0 )
611                 goto out;
612         return 0;
613
614 out:
615         segment_unload(mon_dcss_name);
616 out_device:
617         device_unregister(monreader_device);
618 out_driver:
619         driver_unregister(&monreader_driver);
620 out_iucv:
621         iucv_unregister(&monreader_iucv_handler, 1);
622         return rc;
623 }
624
625 static void __exit mon_exit(void)
626 {
627         segment_unload(mon_dcss_name);
628         WARN_ON(misc_deregister(&mon_dev) != 0);
629         device_unregister(monreader_device);
630         driver_unregister(&monreader_driver);
631         iucv_unregister(&monreader_iucv_handler, 1);
632         return;
633 }
634
635
636 module_init(mon_init);
637 module_exit(mon_exit);
638
639 module_param_string(mondcss, mon_dcss_name, 9, 0444);
640 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
641                  "service, max. 8 chars. Default is MONDCSS");
642
643 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
644 MODULE_DESCRIPTION("Character device driver for reading z/VM "
645                    "monitor service records.");
646 MODULE_LICENSE("GPL");