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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Provide a pstore intermediate backend, organized into kernel memory
4 * allocated zones that are then mapped and flushed into a single
5 * contiguous region on a storage backend of some kind (block, mtd, etc).
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/mount.h>
14#include <linux/printk.h>
15#include <linux/fs.h>
16#include <linux/pstore_zone.h>
17#include <linux/kdev_t.h>
18#include <linux/device.h>
19#include <linux/namei.h>
20#include <linux/fcntl.h>
21#include <linux/uio.h>
22#include <linux/writeback.h>
23#include "internal.h"
24
25/**
26 * struct psz_buffer - header of zone to flush to storage
27 *
28 * @sig: signature to indicate header (PSZ_SIG xor PSZONE-type value)
29 * @datalen: length of data in @data
30 * @start: offset into @data where the beginning of the stored bytes begin
31 * @data: zone data.
32 */
33struct psz_buffer {
34#define PSZ_SIG (0x43474244) /* DBGC */
35 uint32_t sig;
36 atomic_t datalen;
37 atomic_t start;
38 uint8_t data[];
39};
40
41/**
42 * struct psz_kmsg_header - kmsg dump-specific header to flush to storage
43 *
44 * @magic: magic num for kmsg dump header
45 * @time: kmsg dump trigger time
46 * @compressed: whether conpressed
47 * @counter: kmsg dump counter
48 * @reason: the kmsg dump reason (e.g. oops, panic, etc)
49 * @data: pointer to log data
50 *
51 * This is a sub-header for a kmsg dump, trailing after &psz_buffer.
52 */
53struct psz_kmsg_header {
54#define PSTORE_KMSG_HEADER_MAGIC 0x4dfc3ae5 /* Just a random number */
55 uint32_t magic;
56 struct timespec64 time;
57 bool compressed;
58 uint32_t counter;
59 enum kmsg_dump_reason reason;
60 uint8_t data[];
61};
62
63/**
64 * struct pstore_zone - single stored buffer
65 *
66 * @off: zone offset of storage
67 * @type: front-end type for this zone
68 * @name: front-end name for this zone
69 * @buffer: pointer to data buffer managed by this zone
70 * @oldbuf: pointer to old data buffer
71 * @buffer_size: bytes in @buffer->data
72 * @should_recover: whether this zone should recover from storage
73 * @dirty: whether the data in @buffer dirty
74 *
75 * zone structure in memory.
76 */
77struct pstore_zone {
78 loff_t off;
79 const char *name;
80 enum pstore_type_id type;
81
82 struct psz_buffer *buffer;
83 struct psz_buffer *oldbuf;
84 size_t buffer_size;
85 bool should_recover;
86 atomic_t dirty;
87};
88
89/**
90 * struct psz_context - all about running state of pstore/zone
91 *
92 * @kpszs: kmsg dump storage zones
93 * @ppsz: pmsg storage zone
94 * @cpsz: console storage zone
95 * @fpszs: ftrace storage zones
96 * @kmsg_max_cnt: max count of @kpszs
97 * @kmsg_read_cnt: counter of total read kmsg dumps
98 * @kmsg_write_cnt: counter of total kmsg dump writes
99 * @pmsg_read_cnt: counter of total read pmsg zone
100 * @console_read_cnt: counter of total read console zone
101 * @ftrace_max_cnt: max count of @fpszs
102 * @ftrace_read_cnt: counter of max read ftrace zone
103 * @oops_counter: counter of oops dumps
104 * @panic_counter: counter of panic dumps
105 * @recovered: whether finished recovering data from storage
106 * @on_panic: whether panic is happening
107 * @pstore_zone_info_lock: lock to @pstore_zone_info
108 * @pstore_zone_info: information from backend
109 * @pstore: structure for pstore
110 */
111struct psz_context {
112 struct pstore_zone **kpszs;
113 struct pstore_zone *ppsz;
114 struct pstore_zone *cpsz;
115 struct pstore_zone **fpszs;
116 unsigned int kmsg_max_cnt;
117 unsigned int kmsg_read_cnt;
118 unsigned int kmsg_write_cnt;
119 unsigned int pmsg_read_cnt;
120 unsigned int console_read_cnt;
121 unsigned int ftrace_max_cnt;
122 unsigned int ftrace_read_cnt;
123 /*
124 * These counters should be calculated during recovery.
125 * It records the oops/panic times after crashes rather than boots.
126 */
127 unsigned int oops_counter;
128 unsigned int panic_counter;
129 atomic_t recovered;
130 atomic_t on_panic;
131
132 /*
133 * pstore_zone_info_lock protects this entire structure during calls
134 * to register_pstore_zone()/unregister_pstore_zone().
135 */
136 struct mutex pstore_zone_info_lock;
137 struct pstore_zone_info *pstore_zone_info;
138 struct pstore_info pstore;
139};
140static struct psz_context pstore_zone_cxt;
141
142static void psz_flush_all_dirty_zones(struct work_struct *);
143static DECLARE_DELAYED_WORK(psz_cleaner, psz_flush_all_dirty_zones);
144
145/**
146 * enum psz_flush_mode - flush mode for psz_zone_write()
147 *
148 * @FLUSH_NONE: do not flush to storage but update data on memory
149 * @FLUSH_PART: just flush part of data including meta data to storage
150 * @FLUSH_META: just flush meta data of zone to storage
151 * @FLUSH_ALL: flush all of zone
152 */
153enum psz_flush_mode {
154 FLUSH_NONE = 0,
155 FLUSH_PART,
156 FLUSH_META,
157 FLUSH_ALL,
158};
159
160static inline int buffer_datalen(struct pstore_zone *zone)
161{
162 return atomic_read(&zone->buffer->datalen);
163}
164
165static inline int buffer_start(struct pstore_zone *zone)
166{
167 return atomic_read(&zone->buffer->start);
168}
169
170static inline bool is_on_panic(void)
171{
172 return atomic_read(&pstore_zone_cxt.on_panic);
173}
174
175static ssize_t psz_zone_read_buffer(struct pstore_zone *zone, char *buf,
176 size_t len, unsigned long off)
177{
178 if (!buf || !zone || !zone->buffer)
179 return -EINVAL;
180 if (off > zone->buffer_size)
181 return -EINVAL;
182 len = min_t(size_t, len, zone->buffer_size - off);
183 memcpy(buf, zone->buffer->data + off, len);
184 return len;
185}
186
187static int psz_zone_read_oldbuf(struct pstore_zone *zone, char *buf,
188 size_t len, unsigned long off)
189{
190 if (!buf || !zone || !zone->oldbuf)
191 return -EINVAL;
192 if (off > zone->buffer_size)
193 return -EINVAL;
194 len = min_t(size_t, len, zone->buffer_size - off);
195 memcpy(buf, zone->oldbuf->data + off, len);
196 return 0;
197}
198
199static int psz_zone_write(struct pstore_zone *zone,
200 enum psz_flush_mode flush_mode, const char *buf,
201 size_t len, unsigned long off)
202{
203 struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
204 ssize_t wcnt = 0;
205 ssize_t (*writeop)(const char *buf, size_t bytes, loff_t pos);
206 size_t wlen;
207
208 if (off > zone->buffer_size)
209 return -EINVAL;
210
211 wlen = min_t(size_t, len, zone->buffer_size - off);
212 if (buf && wlen) {
213 memcpy(zone->buffer->data + off, buf, wlen);
214 atomic_set(&zone->buffer->datalen, wlen + off);
215 }
216
217 /* avoid to damage old records */
218 if (!is_on_panic() && !atomic_read(&pstore_zone_cxt.recovered))
219 goto dirty;
220
221 writeop = is_on_panic() ? info->panic_write : info->write;
222 if (!writeop)
223 goto dirty;
224
225 switch (flush_mode) {
226 case FLUSH_NONE:
227 if (unlikely(buf && wlen))
228 goto dirty;
229 return 0;
230 case FLUSH_PART:
231 wcnt = writeop((const char *)zone->buffer->data + off, wlen,
232 zone->off + sizeof(*zone->buffer) + off);
233 if (wcnt != wlen)
234 goto dirty;
235 fallthrough;
236 case FLUSH_META:
237 wlen = sizeof(struct psz_buffer);
238 wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
239 if (wcnt != wlen)
240 goto dirty;
241 break;
242 case FLUSH_ALL:
243 wlen = zone->buffer_size + sizeof(*zone->buffer);
244 wcnt = writeop((const char *)zone->buffer, wlen, zone->off);
245 if (wcnt != wlen)
246 goto dirty;
247 break;
248 }
249
250 return 0;
251dirty:
252 /* no need to mark dirty if going to try next zone */
253 if (wcnt == -ENOMSG)
254 return -ENOMSG;
255 atomic_set(&zone->dirty, true);
256 /* flush dirty zones nicely */
257 if (wcnt == -EBUSY && !is_on_panic())
258 schedule_delayed_work(&psz_cleaner, msecs_to_jiffies(500));
259 return -EBUSY;
260}
261
262static int psz_flush_dirty_zone(struct pstore_zone *zone)
263{
264 int ret;
265
266 if (unlikely(!zone))
267 return -EINVAL;
268
269 if (unlikely(!atomic_read(&pstore_zone_cxt.recovered)))
270 return -EBUSY;
271
272 if (!atomic_xchg(&zone->dirty, false))
273 return 0;
274
275 ret = psz_zone_write(zone, FLUSH_ALL, NULL, 0, 0);
276 if (ret)
277 atomic_set(&zone->dirty, true);
278 return ret;
279}
280
281static int psz_flush_dirty_zones(struct pstore_zone **zones, unsigned int cnt)
282{
283 int i, ret;
284 struct pstore_zone *zone;
285
286 if (!zones)
287 return -EINVAL;
288
289 for (i = 0; i < cnt; i++) {
290 zone = zones[i];
291 if (!zone)
292 return -EINVAL;
293 ret = psz_flush_dirty_zone(zone);
294 if (ret)
295 return ret;
296 }
297 return 0;
298}
299
300static int psz_move_zone(struct pstore_zone *old, struct pstore_zone *new)
301{
302 const char *data = (const char *)old->buffer->data;
303 int ret;
304
305 ret = psz_zone_write(new, FLUSH_ALL, data, buffer_datalen(old), 0);
306 if (ret) {
307 atomic_set(&new->buffer->datalen, 0);
308 atomic_set(&new->dirty, false);
309 return ret;
310 }
311 atomic_set(&old->buffer->datalen, 0);
312 return 0;
313}
314
315static void psz_flush_all_dirty_zones(struct work_struct *work)
316{
317 struct psz_context *cxt = &pstore_zone_cxt;
318 int ret = 0;
319
320 if (cxt->ppsz)
321 ret |= psz_flush_dirty_zone(cxt->ppsz);
322 if (cxt->cpsz)
323 ret |= psz_flush_dirty_zone(cxt->cpsz);
324 if (cxt->kpszs)
325 ret |= psz_flush_dirty_zones(cxt->kpszs, cxt->kmsg_max_cnt);
326 if (cxt->fpszs)
327 ret |= psz_flush_dirty_zones(cxt->fpszs, cxt->ftrace_max_cnt);
328 if (ret && cxt->pstore_zone_info)
329 schedule_delayed_work(&psz_cleaner, msecs_to_jiffies(1000));
330}
331
332static int psz_kmsg_recover_data(struct psz_context *cxt)
333{
334 struct pstore_zone_info *info = cxt->pstore_zone_info;
335 struct pstore_zone *zone = NULL;
336 struct psz_buffer *buf;
337 unsigned long i;
338 ssize_t rcnt;
339
340 if (!info->read)
341 return -EINVAL;
342
343 for (i = 0; i < cxt->kmsg_max_cnt; i++) {
344 zone = cxt->kpszs[i];
345 if (unlikely(!zone))
346 return -EINVAL;
347 if (atomic_read(&zone->dirty)) {
348 unsigned int wcnt = cxt->kmsg_write_cnt;
349 struct pstore_zone *new = cxt->kpszs[wcnt];
350 int ret;
351
352 ret = psz_move_zone(zone, new);
353 if (ret) {
354 pr_err("move zone from %lu to %d failed\n",
355 i, wcnt);
356 return ret;
357 }
358 cxt->kmsg_write_cnt = (wcnt + 1) % cxt->kmsg_max_cnt;
359 }
360 if (!zone->should_recover)
361 continue;
362 buf = zone->buffer;
363 rcnt = info->read((char *)buf, zone->buffer_size + sizeof(*buf),
364 zone->off);
365 if (rcnt != zone->buffer_size + sizeof(*buf))
366 return rcnt < 0 ? rcnt : -EIO;
367 }
368 return 0;
369}
370
371static int psz_kmsg_recover_meta(struct psz_context *cxt)
372{
373 struct pstore_zone_info *info = cxt->pstore_zone_info;
374 struct pstore_zone *zone;
375 ssize_t rcnt, len;
376 struct psz_buffer *buf;
377 struct psz_kmsg_header *hdr;
378 struct timespec64 time = { };
379 unsigned long i;
380 /*
381 * Recover may on panic, we can't allocate any memory by kmalloc.
382 * So, we use local array instead.
383 */
384 char buffer_header[sizeof(*buf) + sizeof(*hdr)] = {0};
385
386 if (!info->read)
387 return -EINVAL;
388
389 len = sizeof(*buf) + sizeof(*hdr);
390 buf = (struct psz_buffer *)buffer_header;
391 for (i = 0; i < cxt->kmsg_max_cnt; i++) {
392 zone = cxt->kpszs[i];
393 if (unlikely(!zone))
394 return -EINVAL;
395
396 rcnt = info->read((char *)buf, len, zone->off);
397 if (rcnt == -ENOMSG) {
398 pr_debug("%s with id %lu may be broken, skip\n",
399 zone->name, i);
400 continue;
401 } else if (rcnt != len) {
402 pr_err("read %s with id %lu failed\n", zone->name, i);
403 return rcnt < 0 ? rcnt : -EIO;
404 }
405
406 if (buf->sig != zone->buffer->sig) {
407 pr_debug("no valid data in kmsg dump zone %lu\n", i);
408 continue;
409 }
410
411 if (zone->buffer_size < atomic_read(&buf->datalen)) {
412 pr_info("found overtop zone: %s: id %lu, off %lld, size %zu\n",
413 zone->name, i, zone->off,
414 zone->buffer_size);
415 continue;
416 }
417
418 hdr = (struct psz_kmsg_header *)buf->data;
419 if (hdr->magic != PSTORE_KMSG_HEADER_MAGIC) {
420 pr_info("found invalid zone: %s: id %lu, off %lld, size %zu\n",
421 zone->name, i, zone->off,
422 zone->buffer_size);
423 continue;
424 }
425
426 /*
427 * we get the newest zone, and the next one must be the oldest
428 * or unused zone, because we do write one by one like a circle.
429 */
430 if (hdr->time.tv_sec >= time.tv_sec) {
431 time.tv_sec = hdr->time.tv_sec;
432 cxt->kmsg_write_cnt = (i + 1) % cxt->kmsg_max_cnt;
433 }
434
435 if (hdr->reason == KMSG_DUMP_OOPS)
436 cxt->oops_counter =
437 max(cxt->oops_counter, hdr->counter);
438 else if (hdr->reason == KMSG_DUMP_PANIC)
439 cxt->panic_counter =
440 max(cxt->panic_counter, hdr->counter);
441
442 if (!atomic_read(&buf->datalen)) {
443 pr_debug("found erased zone: %s: id %lu, off %lld, size %zu, datalen %d\n",
444 zone->name, i, zone->off,
445 zone->buffer_size,
446 atomic_read(&buf->datalen));
447 continue;
448 }
449
450 if (!is_on_panic())
451 zone->should_recover = true;
452 pr_debug("found nice zone: %s: id %lu, off %lld, size %zu, datalen %d\n",
453 zone->name, i, zone->off,
454 zone->buffer_size, atomic_read(&buf->datalen));
455 }
456
457 return 0;
458}
459
460static int psz_kmsg_recover(struct psz_context *cxt)
461{
462 int ret;
463
464 if (!cxt->kpszs)
465 return 0;
466
467 ret = psz_kmsg_recover_meta(cxt);
468 if (ret)
469 goto recover_fail;
470
471 ret = psz_kmsg_recover_data(cxt);
472 if (ret)
473 goto recover_fail;
474
475 return 0;
476recover_fail:
477 pr_debug("psz_recover_kmsg failed\n");
478 return ret;
479}
480
481static int psz_recover_zone(struct psz_context *cxt, struct pstore_zone *zone)
482{
483 struct pstore_zone_info *info = cxt->pstore_zone_info;
484 struct psz_buffer *oldbuf, tmpbuf;
485 int ret = 0;
486 char *buf;
487 ssize_t rcnt, len, start, off;
488
489 if (!zone || zone->oldbuf)
490 return 0;
491
492 if (is_on_panic()) {
493 /* save data as much as possible */
494 psz_flush_dirty_zone(zone);
495 return 0;
496 }
497
498 if (unlikely(!info->read))
499 return -EINVAL;
500
501 len = sizeof(struct psz_buffer);
502 rcnt = info->read((char *)&tmpbuf, len, zone->off);
503 if (rcnt != len) {
504 pr_debug("read zone %s failed\n", zone->name);
505 return rcnt < 0 ? rcnt : -EIO;
506 }
507
508 if (tmpbuf.sig != zone->buffer->sig) {
509 pr_debug("no valid data in zone %s\n", zone->name);
510 return 0;
511 }
512
513 if (zone->buffer_size < atomic_read(&tmpbuf.datalen) ||
514 zone->buffer_size < atomic_read(&tmpbuf.start)) {
515 pr_info("found overtop zone: %s: off %lld, size %zu\n",
516 zone->name, zone->off, zone->buffer_size);
517 /* just keep going */
518 return 0;
519 }
520
521 if (!atomic_read(&tmpbuf.datalen)) {
522 pr_debug("found erased zone: %s: off %lld, size %zu, datalen %d\n",
523 zone->name, zone->off, zone->buffer_size,
524 atomic_read(&tmpbuf.datalen));
525 return 0;
526 }
527
528 pr_debug("found nice zone: %s: off %lld, size %zu, datalen %d\n",
529 zone->name, zone->off, zone->buffer_size,
530 atomic_read(&tmpbuf.datalen));
531
532 len = atomic_read(&tmpbuf.datalen) + sizeof(*oldbuf);
533 oldbuf = kzalloc(len, GFP_KERNEL);
534 if (!oldbuf)
535 return -ENOMEM;
536
537 memcpy(oldbuf, &tmpbuf, sizeof(*oldbuf));
538 buf = (char *)oldbuf + sizeof(*oldbuf);
539 len = atomic_read(&oldbuf->datalen);
540 start = atomic_read(&oldbuf->start);
541 off = zone->off + sizeof(*oldbuf);
542
543 /* get part of data */
544 rcnt = info->read(buf, len - start, off + start);
545 if (rcnt != len - start) {
546 pr_err("read zone %s failed\n", zone->name);
547 ret = rcnt < 0 ? rcnt : -EIO;
548 goto free_oldbuf;
549 }
550
551 /* get the rest of data */
552 rcnt = info->read(buf + len - start, start, off);
553 if (rcnt != start) {
554 pr_err("read zone %s failed\n", zone->name);
555 ret = rcnt < 0 ? rcnt : -EIO;
556 goto free_oldbuf;
557 }
558
559 zone->oldbuf = oldbuf;
560 psz_flush_dirty_zone(zone);
561 return 0;
562
563free_oldbuf:
564 kfree(oldbuf);
565 return ret;
566}
567
568static int psz_recover_zones(struct psz_context *cxt,
569 struct pstore_zone **zones, unsigned int cnt)
570{
571 int ret;
572 unsigned int i;
573 struct pstore_zone *zone;
574
575 if (!zones)
576 return 0;
577
578 for (i = 0; i < cnt; i++) {
579 zone = zones[i];
580 if (unlikely(!zone))
581 continue;
582 ret = psz_recover_zone(cxt, zone);
583 if (ret)
584 goto recover_fail;
585 }
586
587 return 0;
588recover_fail:
589 pr_debug("recover %s[%u] failed\n", zone->name, i);
590 return ret;
591}
592
593/**
594 * psz_recovery() - recover data from storage
595 * @cxt: the context of pstore/zone
596 *
597 * recovery means reading data back from storage after rebooting
598 *
599 * Return: 0 on success, others on failure.
600 */
601static inline int psz_recovery(struct psz_context *cxt)
602{
603 int ret;
604
605 if (atomic_read(&cxt->recovered))
606 return 0;
607
608 ret = psz_kmsg_recover(cxt);
609 if (ret)
610 goto out;
611
612 ret = psz_recover_zone(cxt, cxt->ppsz);
613 if (ret)
614 goto out;
615
616 ret = psz_recover_zone(cxt, cxt->cpsz);
617 if (ret)
618 goto out;
619
620 ret = psz_recover_zones(cxt, cxt->fpszs, cxt->ftrace_max_cnt);
621
622out:
623 if (unlikely(ret))
624 pr_err("recover failed\n");
625 else {
626 pr_debug("recover end!\n");
627 atomic_set(&cxt->recovered, 1);
628 }
629 return ret;
630}
631
632static int psz_pstore_open(struct pstore_info *psi)
633{
634 struct psz_context *cxt = psi->data;
635
636 cxt->kmsg_read_cnt = 0;
637 cxt->pmsg_read_cnt = 0;
638 cxt->console_read_cnt = 0;
639 cxt->ftrace_read_cnt = 0;
640 return 0;
641}
642
643static inline bool psz_old_ok(struct pstore_zone *zone)
644{
645 if (zone && zone->oldbuf && atomic_read(&zone->oldbuf->datalen))
646 return true;
647 return false;
648}
649
650static inline bool psz_ok(struct pstore_zone *zone)
651{
652 if (zone && zone->buffer && buffer_datalen(zone))
653 return true;
654 return false;
655}
656
657static inline int psz_kmsg_erase(struct psz_context *cxt,
658 struct pstore_zone *zone, struct pstore_record *record)
659{
660 struct psz_buffer *buffer = zone->buffer;
661 struct psz_kmsg_header *hdr =
662 (struct psz_kmsg_header *)buffer->data;
663 size_t size;
664
665 if (unlikely(!psz_ok(zone)))
666 return 0;
667
668 /* this zone is already updated, no need to erase */
669 if (record->count != hdr->counter)
670 return 0;
671
672 size = buffer_datalen(zone) + sizeof(*zone->buffer);
673 atomic_set(&zone->buffer->datalen, 0);
674 if (cxt->pstore_zone_info->erase)
675 return cxt->pstore_zone_info->erase(size, zone->off);
676 else
677 return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
678}
679
680static inline int psz_record_erase(struct psz_context *cxt,
681 struct pstore_zone *zone)
682{
683 if (unlikely(!psz_old_ok(zone)))
684 return 0;
685
686 kfree(zone->oldbuf);
687 zone->oldbuf = NULL;
688 /*
689 * if there are new data in zone buffer, that means the old data
690 * are already invalid. It is no need to flush 0 (erase) to
691 * block device.
692 */
693 if (!buffer_datalen(zone))
694 return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
695 psz_flush_dirty_zone(zone);
696 return 0;
697}
698
699static int psz_pstore_erase(struct pstore_record *record)
700{
701 struct psz_context *cxt = record->psi->data;
702
703 switch (record->type) {
704 case PSTORE_TYPE_DMESG:
705 if (record->id >= cxt->kmsg_max_cnt)
706 return -EINVAL;
707 return psz_kmsg_erase(cxt, cxt->kpszs[record->id], record);
708 case PSTORE_TYPE_PMSG:
709 return psz_record_erase(cxt, cxt->ppsz);
710 case PSTORE_TYPE_CONSOLE:
711 return psz_record_erase(cxt, cxt->cpsz);
712 case PSTORE_TYPE_FTRACE:
713 if (record->id >= cxt->ftrace_max_cnt)
714 return -EINVAL;
715 return psz_record_erase(cxt, cxt->fpszs[record->id]);
716 default: return -EINVAL;
717 }
718}
719
720static void psz_write_kmsg_hdr(struct pstore_zone *zone,
721 struct pstore_record *record)
722{
723 struct psz_context *cxt = record->psi->data;
724 struct psz_buffer *buffer = zone->buffer;
725 struct psz_kmsg_header *hdr =
726 (struct psz_kmsg_header *)buffer->data;
727
728 hdr->magic = PSTORE_KMSG_HEADER_MAGIC;
729 hdr->compressed = record->compressed;
730 hdr->time.tv_sec = record->time.tv_sec;
731 hdr->time.tv_nsec = record->time.tv_nsec;
732 hdr->reason = record->reason;
733 if (hdr->reason == KMSG_DUMP_OOPS)
734 hdr->counter = ++cxt->oops_counter;
735 else if (hdr->reason == KMSG_DUMP_PANIC)
736 hdr->counter = ++cxt->panic_counter;
737 else
738 hdr->counter = 0;
739}
740
741/*
742 * In case zone is broken, which may occur to MTD device, we try each zones,
743 * start at cxt->kmsg_write_cnt.
744 */
745static inline int notrace psz_kmsg_write_record(struct psz_context *cxt,
746 struct pstore_record *record)
747{
748 size_t size, hlen;
749 struct pstore_zone *zone;
750 unsigned int i;
751
752 for (i = 0; i < cxt->kmsg_max_cnt; i++) {
753 unsigned int zonenum, len;
754 int ret;
755
756 zonenum = (cxt->kmsg_write_cnt + i) % cxt->kmsg_max_cnt;
757 zone = cxt->kpszs[zonenum];
758 if (unlikely(!zone))
759 return -ENOSPC;
760
761 /* avoid destroying old data, allocate a new one */
762 len = zone->buffer_size + sizeof(*zone->buffer);
763 zone->oldbuf = zone->buffer;
764 zone->buffer = kzalloc(len, GFP_ATOMIC);
765 if (!zone->buffer) {
766 zone->buffer = zone->oldbuf;
767 return -ENOMEM;
768 }
769 zone->buffer->sig = zone->oldbuf->sig;
770
771 pr_debug("write %s to zone id %d\n", zone->name, zonenum);
772 psz_write_kmsg_hdr(zone, record);
773 hlen = sizeof(struct psz_kmsg_header);
774 size = min_t(size_t, record->size, zone->buffer_size - hlen);
775 ret = psz_zone_write(zone, FLUSH_ALL, record->buf, size, hlen);
776 if (likely(!ret || ret != -ENOMSG)) {
777 cxt->kmsg_write_cnt = zonenum + 1;
778 cxt->kmsg_write_cnt %= cxt->kmsg_max_cnt;
779 /* no need to try next zone, free last zone buffer */
780 kfree(zone->oldbuf);
781 zone->oldbuf = NULL;
782 return ret;
783 }
784
785 pr_debug("zone %u may be broken, try next dmesg zone\n",
786 zonenum);
787 kfree(zone->buffer);
788 zone->buffer = zone->oldbuf;
789 zone->oldbuf = NULL;
790 }
791
792 return -EBUSY;
793}
794
795static int notrace psz_kmsg_write(struct psz_context *cxt,
796 struct pstore_record *record)
797{
798 int ret;
799
800 /*
801 * Explicitly only take the first part of any new crash.
802 * If our buffer is larger than kmsg_bytes, this can never happen,
803 * and if our buffer is smaller than kmsg_bytes, we don't want the
804 * report split across multiple records.
805 */
806 if (record->part != 1)
807 return -ENOSPC;
808
809 if (!cxt->kpszs)
810 return -ENOSPC;
811
812 ret = psz_kmsg_write_record(cxt, record);
813 if (!ret && is_on_panic()) {
814 /* ensure all data are flushed to storage when panic */
815 pr_debug("try to flush other dirty zones\n");
816 psz_flush_all_dirty_zones(NULL);
817 }
818
819 /* always return 0 as we had handled it on buffer */
820 return 0;
821}
822
823static int notrace psz_record_write(struct pstore_zone *zone,
824 struct pstore_record *record)
825{
826 size_t start, rem;
827 bool is_full_data = false;
828 char *buf;
829 int cnt;
830
831 if (!zone || !record)
832 return -ENOSPC;
833
834 if (atomic_read(&zone->buffer->datalen) >= zone->buffer_size)
835 is_full_data = true;
836
837 cnt = record->size;
838 buf = record->buf;
839 if (unlikely(cnt > zone->buffer_size)) {
840 buf += cnt - zone->buffer_size;
841 cnt = zone->buffer_size;
842 }
843
844 start = buffer_start(zone);
845 rem = zone->buffer_size - start;
846 if (unlikely(rem < cnt)) {
847 psz_zone_write(zone, FLUSH_PART, buf, rem, start);
848 buf += rem;
849 cnt -= rem;
850 start = 0;
851 is_full_data = true;
852 }
853
854 atomic_set(&zone->buffer->start, cnt + start);
855 psz_zone_write(zone, FLUSH_PART, buf, cnt, start);
856
857 /**
858 * psz_zone_write will set datalen as start + cnt.
859 * It work if actual data length lesser than buffer size.
860 * If data length greater than buffer size, pmsg will rewrite to
861 * beginning of zone, which make buffer->datalen wrongly.
862 * So we should reset datalen as buffer size once actual data length
863 * greater than buffer size.
864 */
865 if (is_full_data) {
866 atomic_set(&zone->buffer->datalen, zone->buffer_size);
867 psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
868 }
869 return 0;
870}
871
872static int notrace psz_pstore_write(struct pstore_record *record)
873{
874 struct psz_context *cxt = record->psi->data;
875
876 if (record->type == PSTORE_TYPE_DMESG &&
877 record->reason == KMSG_DUMP_PANIC)
878 atomic_set(&cxt->on_panic, 1);
879
880 /*
881 * if on panic, do not write except panic records
882 * Fix case that panic_write prints log which wakes up console backend.
883 */
884 if (is_on_panic() && record->type != PSTORE_TYPE_DMESG)
885 return -EBUSY;
886
887 switch (record->type) {
888 case PSTORE_TYPE_DMESG:
889 return psz_kmsg_write(cxt, record);
890 case PSTORE_TYPE_CONSOLE:
891 return psz_record_write(cxt->cpsz, record);
892 case PSTORE_TYPE_PMSG:
893 return psz_record_write(cxt->ppsz, record);
894 case PSTORE_TYPE_FTRACE: {
895 int zonenum = smp_processor_id();
896
897 if (!cxt->fpszs)
898 return -ENOSPC;
899 return psz_record_write(cxt->fpszs[zonenum], record);
900 }
901 default:
902 return -EINVAL;
903 }
904}
905
906static struct pstore_zone *psz_read_next_zone(struct psz_context *cxt)
907{
908 struct pstore_zone *zone = NULL;
909
910 while (cxt->kmsg_read_cnt < cxt->kmsg_max_cnt) {
911 zone = cxt->kpszs[cxt->kmsg_read_cnt++];
912 if (psz_ok(zone))
913 return zone;
914 }
915
916 if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
917 /*
918 * No need psz_old_ok(). Let psz_ftrace_read() do so for
919 * combination. psz_ftrace_read() should traverse over
920 * all zones in case of some zone without data.
921 */
922 return cxt->fpszs[cxt->ftrace_read_cnt++];
923
924 if (cxt->pmsg_read_cnt == 0) {
925 cxt->pmsg_read_cnt++;
926 zone = cxt->ppsz;
927 if (psz_old_ok(zone))
928 return zone;
929 }
930
931 if (cxt->console_read_cnt == 0) {
932 cxt->console_read_cnt++;
933 zone = cxt->cpsz;
934 if (psz_old_ok(zone))
935 return zone;
936 }
937
938 return NULL;
939}
940
941static int psz_kmsg_read_hdr(struct pstore_zone *zone,
942 struct pstore_record *record)
943{
944 struct psz_buffer *buffer = zone->buffer;
945 struct psz_kmsg_header *hdr =
946 (struct psz_kmsg_header *)buffer->data;
947
948 if (hdr->magic != PSTORE_KMSG_HEADER_MAGIC)
949 return -EINVAL;
950 record->compressed = hdr->compressed;
951 record->time.tv_sec = hdr->time.tv_sec;
952 record->time.tv_nsec = hdr->time.tv_nsec;
953 record->reason = hdr->reason;
954 record->count = hdr->counter;
955 return 0;
956}
957
958static ssize_t psz_kmsg_read(struct pstore_zone *zone,
959 struct pstore_record *record)
960{
961 ssize_t size, hlen = 0;
962
963 size = buffer_datalen(zone);
964 /* Clear and skip this kmsg dump record if it has no valid header */
965 if (psz_kmsg_read_hdr(zone, record)) {
966 atomic_set(&zone->buffer->datalen, 0);
967 atomic_set(&zone->dirty, 0);
968 return -ENOMSG;
969 }
970 size -= sizeof(struct psz_kmsg_header);
971
972 if (!record->compressed) {
973 char *buf = kasprintf(GFP_KERNEL, "%s: Total %d times\n",
974 kmsg_dump_reason_str(record->reason),
975 record->count);
976 if (!buf)
977 return -ENOMEM;
978 hlen = strlen(buf);
979 record->buf = krealloc(buf, hlen + size, GFP_KERNEL);
980 if (!record->buf) {
981 kfree(buf);
982 return -ENOMEM;
983 }
984 } else {
985 record->buf = kmalloc(size, GFP_KERNEL);
986 if (!record->buf)
987 return -ENOMEM;
988 }
989
990 size = psz_zone_read_buffer(zone, record->buf + hlen, size,
991 sizeof(struct psz_kmsg_header));
992 if (unlikely(size < 0)) {
993 kfree(record->buf);
994 return -ENOMSG;
995 }
996
997 return size + hlen;
998}
999
1000/* try to combine all ftrace zones */
1001static ssize_t psz_ftrace_read(struct pstore_zone *zone,
1002 struct pstore_record *record)
1003{
1004 struct psz_context *cxt;
1005 struct psz_buffer *buf;
1006 int ret;
1007
1008 if (!zone || !record)
1009 return -ENOSPC;
1010
1011 if (!psz_old_ok(zone))
1012 goto out;
1013
1014 buf = (struct psz_buffer *)zone->oldbuf;
1015 if (!buf)
1016 return -ENOMSG;
1017
1018 ret = pstore_ftrace_combine_log(&record->buf, &record->size,
1019 (char *)buf->data, atomic_read(&buf->datalen));
1020 if (unlikely(ret))
1021 return ret;
1022
1023out:
1024 cxt = record->psi->data;
1025 if (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt)
1026 /* then, read next ftrace zone */
1027 return -ENOMSG;
1028 record->id = 0;
1029 return record->size ? record->size : -ENOMSG;
1030}
1031
1032static ssize_t psz_record_read(struct pstore_zone *zone,
1033 struct pstore_record *record)
1034{
1035 size_t len;
1036 struct psz_buffer *buf;
1037
1038 if (!zone || !record)
1039 return -ENOSPC;
1040
1041 buf = (struct psz_buffer *)zone->oldbuf;
1042 if (!buf)
1043 return -ENOMSG;
1044
1045 len = atomic_read(&buf->datalen);
1046 record->buf = kmalloc(len, GFP_KERNEL);
1047 if (!record->buf)
1048 return -ENOMEM;
1049
1050 if (unlikely(psz_zone_read_oldbuf(zone, record->buf, len, 0))) {
1051 kfree(record->buf);
1052 return -ENOMSG;
1053 }
1054
1055 return len;
1056}
1057
1058static ssize_t psz_pstore_read(struct pstore_record *record)
1059{
1060 struct psz_context *cxt = record->psi->data;
1061 ssize_t (*readop)(struct pstore_zone *zone,
1062 struct pstore_record *record);
1063 struct pstore_zone *zone;
1064 ssize_t ret;
1065
1066 /* before read, we must recover from storage */
1067 ret = psz_recovery(cxt);
1068 if (ret)
1069 return ret;
1070
1071next_zone:
1072 zone = psz_read_next_zone(cxt);
1073 if (!zone)
1074 return 0;
1075
1076 record->type = zone->type;
1077 switch (record->type) {
1078 case PSTORE_TYPE_DMESG:
1079 readop = psz_kmsg_read;
1080 record->id = cxt->kmsg_read_cnt - 1;
1081 break;
1082 case PSTORE_TYPE_FTRACE:
1083 readop = psz_ftrace_read;
1084 break;
1085 case PSTORE_TYPE_CONSOLE:
1086 case PSTORE_TYPE_PMSG:
1087 readop = psz_record_read;
1088 break;
1089 default:
1090 goto next_zone;
1091 }
1092
1093 ret = readop(zone, record);
1094 if (ret == -ENOMSG)
1095 goto next_zone;
1096 return ret;
1097}
1098
1099static struct psz_context pstore_zone_cxt = {
1100 .pstore_zone_info_lock =
1101 __MUTEX_INITIALIZER(pstore_zone_cxt.pstore_zone_info_lock),
1102 .recovered = ATOMIC_INIT(0),
1103 .on_panic = ATOMIC_INIT(0),
1104 .pstore = {
1105 .owner = THIS_MODULE,
1106 .open = psz_pstore_open,
1107 .read = psz_pstore_read,
1108 .write = psz_pstore_write,
1109 .erase = psz_pstore_erase,
1110 },
1111};
1112
1113static void psz_free_zone(struct pstore_zone **pszone)
1114{
1115 struct pstore_zone *zone = *pszone;
1116
1117 if (!zone)
1118 return;
1119
1120 kfree(zone->buffer);
1121 kfree(zone);
1122 *pszone = NULL;
1123}
1124
1125static void psz_free_zones(struct pstore_zone ***pszones, unsigned int *cnt)
1126{
1127 struct pstore_zone **zones = *pszones;
1128
1129 if (!zones)
1130 return;
1131
1132 while (*cnt > 0) {
1133 (*cnt)--;
1134 psz_free_zone(&(zones[*cnt]));
1135 }
1136 kfree(zones);
1137 *pszones = NULL;
1138}
1139
1140static void psz_free_all_zones(struct psz_context *cxt)
1141{
1142 if (cxt->kpszs)
1143 psz_free_zones(&cxt->kpszs, &cxt->kmsg_max_cnt);
1144 if (cxt->ppsz)
1145 psz_free_zone(&cxt->ppsz);
1146 if (cxt->cpsz)
1147 psz_free_zone(&cxt->cpsz);
1148 if (cxt->fpszs)
1149 psz_free_zones(&cxt->fpszs, &cxt->ftrace_max_cnt);
1150}
1151
1152static struct pstore_zone *psz_init_zone(enum pstore_type_id type,
1153 loff_t *off, size_t size)
1154{
1155 struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
1156 struct pstore_zone *zone;
1157 const char *name = pstore_type_to_name(type);
1158
1159 if (!size)
1160 return NULL;
1161
1162 if (*off + size > info->total_size) {
1163 pr_err("no room for %s (0x%zx@0x%llx over 0x%lx)\n",
1164 name, size, *off, info->total_size);
1165 return ERR_PTR(-ENOMEM);
1166 }
1167
1168 zone = kzalloc(sizeof(struct pstore_zone), GFP_KERNEL);
1169 if (!zone)
1170 return ERR_PTR(-ENOMEM);
1171
1172 zone->buffer = kmalloc(size, GFP_KERNEL);
1173 if (!zone->buffer) {
1174 kfree(zone);
1175 return ERR_PTR(-ENOMEM);
1176 }
1177 memset(zone->buffer, 0xFF, size);
1178 zone->off = *off;
1179 zone->name = name;
1180 zone->type = type;
1181 zone->buffer_size = size - sizeof(struct psz_buffer);
1182 zone->buffer->sig = type ^ PSZ_SIG;
1183 zone->oldbuf = NULL;
1184 atomic_set(&zone->dirty, 0);
1185 atomic_set(&zone->buffer->datalen, 0);
1186 atomic_set(&zone->buffer->start, 0);
1187
1188 *off += size;
1189
1190 pr_debug("pszone %s: off 0x%llx, %zu header, %zu data\n", zone->name,
1191 zone->off, sizeof(*zone->buffer), zone->buffer_size);
1192 return zone;
1193}
1194
1195static struct pstore_zone **psz_init_zones(enum pstore_type_id type,
1196 loff_t *off, size_t total_size, ssize_t record_size,
1197 unsigned int *cnt)
1198{
1199 struct pstore_zone_info *info = pstore_zone_cxt.pstore_zone_info;
1200 struct pstore_zone **zones, *zone;
1201 const char *name = pstore_type_to_name(type);
1202 int c, i;
1203
1204 *cnt = 0;
1205 if (!total_size || !record_size)
1206 return NULL;
1207
1208 if (*off + total_size > info->total_size) {
1209 pr_err("no room for zones %s (0x%zx@0x%llx over 0x%lx)\n",
1210 name, total_size, *off, info->total_size);
1211 return ERR_PTR(-ENOMEM);
1212 }
1213
1214 c = total_size / record_size;
1215 zones = kcalloc(c, sizeof(*zones), GFP_KERNEL);
1216 if (!zones) {
1217 pr_err("allocate for zones %s failed\n", name);
1218 return ERR_PTR(-ENOMEM);
1219 }
1220
1221 for (i = 0; i < c; i++) {
1222 zone = psz_init_zone(type, off, record_size);
1223 if (!zone || IS_ERR(zone)) {
1224 pr_err("initialize zones %s failed\n", name);
1225 psz_free_zones(&zones, &i);
1226 return (void *)zone;
1227 }
1228 zones[i] = zone;
1229 }
1230
1231 *cnt = c;
1232 return zones;
1233}
1234
1235static int psz_alloc_zones(struct psz_context *cxt)
1236{
1237 struct pstore_zone_info *info = cxt->pstore_zone_info;
1238 loff_t off = 0;
1239 int err;
1240 size_t off_size = 0;
1241
1242 off_size += info->pmsg_size;
1243 cxt->ppsz = psz_init_zone(PSTORE_TYPE_PMSG, &off, info->pmsg_size);
1244 if (IS_ERR(cxt->ppsz)) {
1245 err = PTR_ERR(cxt->ppsz);
1246 cxt->ppsz = NULL;
1247 goto free_out;
1248 }
1249
1250 off_size += info->console_size;
1251 cxt->cpsz = psz_init_zone(PSTORE_TYPE_CONSOLE, &off,
1252 info->console_size);
1253 if (IS_ERR(cxt->cpsz)) {
1254 err = PTR_ERR(cxt->cpsz);
1255 cxt->cpsz = NULL;
1256 goto free_out;
1257 }
1258
1259 off_size += info->ftrace_size;
1260 cxt->fpszs = psz_init_zones(PSTORE_TYPE_FTRACE, &off,
1261 info->ftrace_size,
1262 info->ftrace_size / nr_cpu_ids,
1263 &cxt->ftrace_max_cnt);
1264 if (IS_ERR(cxt->fpszs)) {
1265 err = PTR_ERR(cxt->fpszs);
1266 cxt->fpszs = NULL;
1267 goto free_out;
1268 }
1269
1270 cxt->kpszs = psz_init_zones(PSTORE_TYPE_DMESG, &off,
1271 info->total_size - off_size,
1272 info->kmsg_size, &cxt->kmsg_max_cnt);
1273 if (IS_ERR(cxt->kpszs)) {
1274 err = PTR_ERR(cxt->kpszs);
1275 cxt->kpszs = NULL;
1276 goto free_out;
1277 }
1278
1279 return 0;
1280free_out:
1281 psz_free_all_zones(cxt);
1282 return err;
1283}
1284
1285/**
1286 * register_pstore_zone() - register to pstore/zone
1287 *
1288 * @info: back-end driver information. See &struct pstore_zone_info.
1289 *
1290 * Only one back-end at one time.
1291 *
1292 * Return: 0 on success, others on failure.
1293 */
1294int register_pstore_zone(struct pstore_zone_info *info)
1295{
1296 int err = -EINVAL;
1297 struct psz_context *cxt = &pstore_zone_cxt;
1298
1299 if (info->total_size < 4096) {
1300 pr_warn("total_size must be >= 4096\n");
1301 return -EINVAL;
1302 }
1303 if (info->total_size > SZ_128M) {
1304 pr_warn("capping size to 128MiB\n");
1305 info->total_size = SZ_128M;
1306 }
1307
1308 if (!info->kmsg_size && !info->pmsg_size && !info->console_size &&
1309 !info->ftrace_size) {
1310 pr_warn("at least one record size must be non-zero\n");
1311 return -EINVAL;
1312 }
1313
1314 if (!info->name || !info->name[0])
1315 return -EINVAL;
1316
1317#define check_size(name, size) { \
1318 if (info->name > 0 && info->name < (size)) { \
1319 pr_err(#name " must be over %d\n", (size)); \
1320 return -EINVAL; \
1321 } \
1322 if (info->name & (size - 1)) { \
1323 pr_err(#name " must be a multiple of %d\n", \
1324 (size)); \
1325 return -EINVAL; \
1326 } \
1327 }
1328
1329 check_size(total_size, 4096);
1330 check_size(kmsg_size, SECTOR_SIZE);
1331 check_size(pmsg_size, SECTOR_SIZE);
1332 check_size(console_size, SECTOR_SIZE);
1333 check_size(ftrace_size, SECTOR_SIZE);
1334
1335#undef check_size
1336
1337 /*
1338 * the @read and @write must be applied.
1339 * if no @read, pstore may mount failed.
1340 * if no @write, pstore do not support to remove record file.
1341 */
1342 if (!info->read || !info->write) {
1343 pr_err("no valid general read/write interface\n");
1344 return -EINVAL;
1345 }
1346
1347 mutex_lock(&cxt->pstore_zone_info_lock);
1348 if (cxt->pstore_zone_info) {
1349 pr_warn("'%s' already loaded: ignoring '%s'\n",
1350 cxt->pstore_zone_info->name, info->name);
1351 mutex_unlock(&cxt->pstore_zone_info_lock);
1352 return -EBUSY;
1353 }
1354 cxt->pstore_zone_info = info;
1355
1356 pr_debug("register %s with properties:\n", info->name);
1357 pr_debug("\ttotal size : %ld Bytes\n", info->total_size);
1358 pr_debug("\tkmsg size : %ld Bytes\n", info->kmsg_size);
1359 pr_debug("\tpmsg size : %ld Bytes\n", info->pmsg_size);
1360 pr_debug("\tconsole size : %ld Bytes\n", info->console_size);
1361 pr_debug("\tftrace size : %ld Bytes\n", info->ftrace_size);
1362
1363 err = psz_alloc_zones(cxt);
1364 if (err) {
1365 pr_err("alloc zones failed\n");
1366 goto fail_out;
1367 }
1368
1369 if (info->kmsg_size) {
1370 cxt->pstore.bufsize = cxt->kpszs[0]->buffer_size -
1371 sizeof(struct psz_kmsg_header);
1372 cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
1373 if (!cxt->pstore.buf) {
1374 err = -ENOMEM;
1375 goto fail_free;
1376 }
1377 }
1378 cxt->pstore.data = cxt;
1379
1380 pr_info("registered %s as backend for", info->name);
1381 cxt->pstore.max_reason = info->max_reason;
1382 cxt->pstore.name = info->name;
1383 if (info->kmsg_size) {
1384 cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
1385 pr_cont(" kmsg(%s",
1386 kmsg_dump_reason_str(cxt->pstore.max_reason));
1387 if (cxt->pstore_zone_info->panic_write)
1388 pr_cont(",panic_write");
1389 pr_cont(")");
1390 }
1391 if (info->pmsg_size) {
1392 cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
1393 pr_cont(" pmsg");
1394 }
1395 if (info->console_size) {
1396 cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
1397 pr_cont(" console");
1398 }
1399 if (info->ftrace_size) {
1400 cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
1401 pr_cont(" ftrace");
1402 }
1403 pr_cont("\n");
1404
1405 err = pstore_register(&cxt->pstore);
1406 if (err) {
1407 pr_err("registering with pstore failed\n");
1408 goto fail_free;
1409 }
1410 mutex_unlock(&pstore_zone_cxt.pstore_zone_info_lock);
1411
1412 return 0;
1413
1414fail_free:
1415 kfree(cxt->pstore.buf);
1416 cxt->pstore.buf = NULL;
1417 cxt->pstore.bufsize = 0;
1418 psz_free_all_zones(cxt);
1419fail_out:
1420 pstore_zone_cxt.pstore_zone_info = NULL;
1421 mutex_unlock(&pstore_zone_cxt.pstore_zone_info_lock);
1422 return err;
1423}
1424EXPORT_SYMBOL_GPL(register_pstore_zone);
1425
1426/**
1427 * unregister_pstore_zone() - unregister to pstore/zone
1428 *
1429 * @info: back-end driver information. See struct pstore_zone_info.
1430 */
1431void unregister_pstore_zone(struct pstore_zone_info *info)
1432{
1433 struct psz_context *cxt = &pstore_zone_cxt;
1434
1435 mutex_lock(&cxt->pstore_zone_info_lock);
1436 if (!cxt->pstore_zone_info) {
1437 mutex_unlock(&cxt->pstore_zone_info_lock);
1438 return;
1439 }
1440
1441 /* Stop incoming writes from pstore. */
1442 pstore_unregister(&cxt->pstore);
1443
1444 /* Flush any pending writes. */
1445 psz_flush_all_dirty_zones(NULL);
1446 flush_delayed_work(&psz_cleaner);
1447
1448 /* Clean up allocations. */
1449 kfree(cxt->pstore.buf);
1450 cxt->pstore.buf = NULL;
1451 cxt->pstore.bufsize = 0;
1452 cxt->pstore_zone_info = NULL;
1453
1454 psz_free_all_zones(cxt);
1455
1456 /* Clear counters and zone state. */
1457 cxt->oops_counter = 0;
1458 cxt->panic_counter = 0;
1459 atomic_set(&cxt->recovered, 0);
1460 atomic_set(&cxt->on_panic, 0);
1461
1462 mutex_unlock(&cxt->pstore_zone_info_lock);
1463}
1464EXPORT_SYMBOL_GPL(unregister_pstore_zone);
1465
1466MODULE_LICENSE("GPL");
1467MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>");
1468MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
1469MODULE_DESCRIPTION("Storage Manager for pstore/blk");